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Interesting Excerpts
The following excerpts are from articles or books that I have recently read. They caught my interest and I hope that you will find them worth reading. If one does spark an action on your part and you want to learn more or you choose to cite it, I urge you to actually read the article or source so that you better understand the perspective of the author(s).
Tackling the Toughest Tech

[These excerpts are from an article by Wade Roush in the April 2020 issue of Scientifi American.]

      Some global crises, such as climate change, are too big to overcome through individual action or even through government-level policy change. To survive this century, we are also going to need some huge science and engineering breakthroughs—especially in areas such as energy and transportation. Unfortunately, the systems we have built to encourage innovation are in a dismal state.

      Federal investment in R&D as a share of the overall economy is lower than at any point in the past 60 years. And venture capital—the industry that is supposed to take risky ideas from government or university laboratories and turn them into valuable businesses—has instead spent the past decade investing in low-stakes tech that helps us order takeout, avoid taxis, swap seines and overpay for desk space. Many of Silicon Valley’s “unicorns” are doing no more to improve the world than their mythical namesakes….

      There is, however, at least one bright spot in the world of tech investing. I got a glimpse of it on a recent visit to The Engine, a for-profit venture firm set up in 2016 by the Massachusetts Institute of Technology. It is designed to fund ambitious ideas in areas it calls “tough tech”: energy, nanotechnology, quantum computing, immunotherapy and other fields where the technical and regulatory challenges are too daunting for most venture capitalists.

      A case in point: Commonwealth Fusion Systems. The Engine-backed start-up has turned a former Radio Shack down the street from M.I.T. into a lab where it tests components for future fusion reactors that could produce nearly inexhaustible, economical, carbon-free energy with vastly less radioactive waste than conventional nukes—an elusive goal that scientists have been trying in vain to accomplish for more than half a century. Chief operating officer Steve Renter says Commonwealth’s “Kitty Hawk moment”—when it proves its demonstration machine can generate more energy than it consumes—could come as soon as 2025….

      Part of what sets The Engine apart is the timescale of its $200-million fund. Limited-partner investors know they might not get their money back for 18 years or more, compared with the eight- to 12-year life of a typical venture fund. Plus, the firm provides lab space and equipment in addition to mentorship and networking. And it welcomes companies that hopscotch across disciplines in ways that might puzzle other investors….

      There are 20 start-ups at The Engine right now, and the firm is renovating an old Polaroid building that will soon hold 100 companies and 800 entrepreneurs. Researchers come to The Engine not because they are trying to make a quick buck but because they have an idea they can't bring alive anywhere else….

DNA Trap

[These excerpts are from an article by Harini Barath in the April 2020 issue of Scientific American.]

      Scientists have crafted a trap for the dengue virus using a scaffold made from fragments of DNA. The star-shaped structure is engineered to single out the virus in the bloodstream and latch on to it with precision, providing a powerful yet simple test to detect the mosquito-transmitted disease.

      Dengue is the world’s fastest-growing vector-borne disease, with multiple serious outbreaks in 2019. In its severe forms, it can cause internal bleeding and is sometimes fatal_ There is no widely accepted vaccine or targeted treatment for dengue, so accurate early detection is crucial.

      The spherical surface of the dengue virus is peppered with antigens, special proteins the virus uses to attach to the cells it infects. Scientists…constructed a flexible scaffold using DNA nanotechnology to mirror the proteins’ arrangement on a hemisphere of the viral surface. The tips and vertices of this five-pointed “DNA star” align with the antigens and carry molecules that they glom on to. The multiple attachment points make the binding strong and very precise…the DNA star targets only viruses with that particular pattern. Once binding occurs, the star fluoresces, or lights up….

      Current gold-standard dengue tests require sophisticated laboratory set-ups and training. “Our technology is very sim-ple; we need only one to two minutes, and the cost is only 50 cents for each test”….the researchers compare their technology with current clinical tests and make a case for its superior sensitivity and accuracy. It should work before symptoms appear, and the DNA nanostructures are nontoxic and friendly to human tissue, the researchers say.

Vanquishing False Idols, Then and Now

[These excerpts are from an article by Kevin P. Weinfurt in the 30 March 2020 issue of Science.]

      In the early 17th century, the English philosopher and statesman Francis Bacon envisioned a bold, multiphase program to accumulate knowledge of the natural world. A critical part of this plan was Novum Organum, which celebrates its 400th anniversary this year. In this work, Bacon attempted to undo the centuries-old dominance of Aristotelian forms of inquiry, encouraging readers to instead apply inductive reasoning to carefully curated observations of the natural world.

      “Book One” of Novum Organum addressed why so little progress had thus far been made in understanding nature. Here, Bacon cautioned against “idols and false notions” that can interfere with the quest for scientific knowledge, providing the first and possibly the most comprehensive catalog of human foibles that can threaten the integrity of science….

      Bacon, a contemporary of Galileo and Shakespeare, wrote Novum Organum at a time when many still believed that truths about the world were handed down by monarchs and ministers. He spoke for the burgeoning empirical sciences, encouraging readers to use the inductive method to throw off the shackles of authority. But if we are to realize his vision for a practice of science that frees people from the shackles of both authority and their own minds, it might be a good idea to update the idols to reflect the modern challenges threatening the scientific enterprise today….

      One year after the publication of Novum Organum, Bacon, who was seriously in debt, was accused of corruption, briefly jailed in the Tower of London, and barred from Parliament for life. It took several decades before his work began to receive wide praise, and in 1660 it inspired the creation of the Royal Society. A modern reader might be similarly inspired by Novum Organum’s subtlety of thought, commitment to understanding nature as it is, and excitement about the potential for science to be a liberating force for humankind.

Sexism and the Stars

[These excerpts are from a book review by Jennifer Carson in the 30 March 2020 issue of Science.]

      In the early 20th century, astronomers believed in a uniformity principle that held that all objects in the universe were made of the same elements, in approximately the same amounts. In 1925, however, Cecilia Payne, a Ph.D. student at Harvard, discovered that stars are composed of a million times more hydrogen than was previously assumed. But because she was young and female, the scientific community rejected her findings. It would take several decades before Payne-Gaposchldn received Lthe recognition she was due….

      The reader meets physics luminaries and future Nobel Prize winners in the Cavendish laboratory, where Payne-Gaposchkin trained as an undergraduate. The lab was directed by J. J. Thomson when she arrived and Ernest Rutherford when she left. (Thomson, incidentally, believed that women “simply did not have the intellectual capacity to be world-class physicists.”) Payne-Gaposchkin was also taught by Niels Bohr, whose quantum theory of atomic structure would enable her to come to her own revolutionary conclusions.

      By the end of her time at Cambridge, it had become clear to Payne-Gaposchkin that she would never be employed as an astronomer in England. So she secured a fellowship at the Harvard Observatory and moved to America. Here, she was granted research opportunities, but the discrimination she had experienced at home continued.

      One of the most egregious perpetrators of this discrimination was Harvard’s president, Abbott Lawrence Lowell, who declared that Payne-Gaposchkin would never be named a professor as long as he was alive. “Lowell had tried to limit Jewish enrollment at Harvard to 15 percent, and he tried to ban black students from living in the freshman dorms. In both instances, the Harvard Board of Overseers overruled him.” writes Moore. “The board did not overrule him, however, when he decreed in 1928 that women should not receive teaching appointments from the Harvard Corporation.” Payne-Gaposchkin was devastated…

      Despite these and other hardships, Payne-Gaposchkin’s accomplishments were remarkable. She wrote several books and more than 270 journal articles, was elected to both the Royal and American Astronomical Societies and the American Philosophical Society, earned an honorary doctorate from Smith College, and was the first woman to receive the American Astronomical Society’s lifetime achievement award. In 1956, after Lowell’s death, she was named the first female professor at Harvard. She died just before the election that would have admitted her to the National Academy of Sciences.

      …This is a view Payne-Gaposchkin echoed in her own memoir: “Do not undertake a scientific career in quest of fame or money. There are easier and better ways to reach them. Undertake it only if nothing else will satisfy you; for nothing else is probably what you will receive.”

How I Faced My Coronavirus Anxiety

[These excerpts are from an article by Kai Liu in the 30 March 2020 issue of Science.]

      In early February, I was working from home when I received a message informing me—and all the other professors at my university in China—that courses would be taught online because of the novel coronavirus. I was already feeling anxious about the mounting epidemic, and my university had locked its doors a few days earlier. Then, when I realized I’d have to teach students online, my anxiety level grew. I didn’t have any experience with online teaching platforms. I was also skeptical about how effective they’d be. “How will I gauge the students’ reactions to my lectures through a computer screen?” I wondered. “Will they learn anything?”

      …Years ago, I’d heard that Taoism philosophies were helpful for finding internal peace. So, I decided to listen to a few recordings. One instructed listeners to “govern [yourself] by doing nothing that goes against nature.” That resonated with me because I realized that I’d been trying to push my anxieties aside and force myself to concentrate on work—an approach that wasn’t working because it didn't feel natural. From then on, I told myself that it was OK to feel anxious, even if it impeded my work. That helped to lessen my internal struggles.

      Over the past 2 months, I’ve also learned how to teach courses online, and I have found unexpected joy in that process—even though I struggled at first….

      My first lecture was especially difficult because I couldn’t see the students’ faces. I was accustomed to lecturing in front of an audience. Online, I felt like I was speaking at my students but not getting anything in return. I communicated with a few of them afterward to get their feedback and they agreed with me, saying that I needed to find a way to make my lectures more interactive. So, I started to encourage my students to leave questions for me in the platform’s comment section during my lectures.

      Almost immediately, my students started peppering me with questions. I was surprised by the level of engagement. In a normal classroom setting, they are afraid to raise their hands; most wait until after the lecture is over to approach me and ask a question. But online, students were more comfortable sharing their questions in front of the entire class. That was a great outcome because if one student has a question, it’s likely that another student has the same question and would benefit from hearing the answer. I’ve also been pleased to see from the homework assignments that they are following my teaching well….

Time to Pull Together

[These excerpts are from an editorial by H. Holden Thorp in the 30 March 2020 issue of Science.]

      It is now hard to imagine a world that isn’t permanently changed by coronavirus disease 2019 (COVID-19). We don't know whether this is an event like 9/11 or the 2008 global financial crisis—where life will mostly go back to the way it was—or whether the institutions and practices of the future will transform in ways that we can’t yet imagine. The success of the world's scientists—along with strong political and social leadership—will determine which scenarios unfold, so it is time to focus on what we can all do to help.

      On the political front, there is finally some progress as exceptional public servants have emerged as the face of the crisis….as the steadfast and consistent messengers during this crisis is reassuring for citizens and for the experts who are working tirelessly to find answers.

      And indeed, there are very important questions to answer. Will recovery from the first infection confer lasting immunity? Will the first vaccine that proves it works cause side effects that undermine its value? Will the vaccines under development trigger neutralizing antibodies? Do widely used inhibitors of angiotensin-converting enzyme promote or inhibit infection? Will the broad-spectrum antiviral drug remdesivir or viral protease inhibitors thwart the virus?

      Then there are also public health and epidemiology questions. Do school closings help or hurt? What happens if hospitals become overwhelmed? If we discover an effective vaccine or drug, can enough be made and delivered to everyone? What are the long-term effects of this crisis on mental health, social well-being, and the economy? What happens when social restrictions, like those in China, are lifted?

      We can draw hope from the science at work….The only way questions will be answered is if scientists can do their work, because scientific knowledge is often the key to knowing what actions to take. So, institutions need to do everything possible to allow these folks to get to the lab safely. Research institutions need to shut down all functions except for clinical care, research on the virus, and public health communication. To support these vital operations, institutions need to provide childcare for scientists and staff whose children are now home from school. And they need to alleviate concerns about the future for these staff by extending tenure clocks, guaranteeing status in graduate school, and extending postdoctoral contracts.

      As for the scientific community who are not working on the virus—we know well that other major problems still exist, such as climate change, inequality, and other diseases. It is understandably very difficult to pause research in other arenas for an indefinite amount of time. This crisis is calling for extraordinary measures….Working from home will make it safer for those who must be in buildings and laboratories to do work related to the virus—fewer people in the hallways, lunchrooms, and other public areas will slow the spread of the virus so that work on COVID-19 can continue….

      On so many fronts, this is a battle of a lifetime and a test of our responsibilities for each other and the strength of our compassion….

A Cut Above

[This excerpt is from an article by Jillian Kramer in the April 2020 issue of Scientific American.]

      Hemorrhage—blood escaping profusely from a ruptured vessel—is a leading cause of potentially preventable death. Bandages often fail to stop the bleeding. But researchers say they have developed a better kind of dressing: one that repels blood and bacteria, promotes quick clotting and detaches without reopening the initial wound.

      While developing blood-repelling coat-ings for medical devices, scientists…found that one mixture of carbon nanofibers and silicone had an unexpected effect: it boosted blood clotting. So they sprayed the mixture onto conventional cotton gauze and applied heat to make it stick. In laboratory tests and experiments with rats, they observed that this new bandage promoted the production of fibrins, proteins that form a meshlike network at wound sites to aid clotting. The bandage also stayed dry, repelling blood, which made it easy to pull away from a wound—and an investigation using Escherichia coil showed that bacteria in a solution could not adhere to the material….

      …more tests are needed to understand why the nanofibers encourage fibrin formation. But…producing the material is inexpensive and could be replicated on a larger scale.…

      …human trials would be needed to prove the bandage’s real capabilities….

If You Learn A, Will You Be Better Able to Learn B?

[These excerpts are from an article by Pedro De Bruyckere, Paul A. Kirschner and Casper Hulshof in the Spring 2020 iissue of American Educator.]

      …Transfer of learning is seen as the use of knowledge, skills, and/or attitudesthat you’ve learned in one situation in a different situation. This new situation can be either a similar situation (near transfer) or a dissimilar situation (far transfer). In recent years, we’ve encountered numerous different forms that claim to be examples of far transfer:

   • Learn how to program, so that you can more easily learn mathematics.

   • Learn Latin, so that you can better learn other languages.

   • Learn music, so that you can better learn arithmetic.

   • Learn chess, so that you can better learn to do just about everything!

      But are these claims justified? Are they really examples of far transfer?

      …Far transfer was an idea first examined in 1923 by Edward Thorndike….

      To explain such situations, Thorndike formulated his theory of identical elements, which posits that near and far transfer can best be regarded as a continuum. Or to paraphrase his basic conclusion: transfer is easier in relation to the extent that there are more similar or identical elements between what has already been learned and what needs to be learned in the future. Accordingly, he argued that near transfer is, by definition, much easier than far transfer. If we were to take the precepts of this “old” theory at face value, the outlook for the advocates of far transfer might be fairly pessimistic….

      In 2011, chess became a compulsory subject in Armenian schools. Armenian authorities were convinced that chess is the key to success at school and in life. By making chess mandatory. they hoped to teach children how to think creatively and strategically. As a result, they will become more intelligent and be better able to solve problems. What's more, this does not just mean chess problems, but all problems in all other school subjects, as well as in later life. If true, this is extremely far transfer. There are indeed research studies that demonstrate a link between chess mastery and improved cognitive skills and work performance.

      In essence, what the Armenian Ministry of Education was saying is that learning how to play chess not only is the key to developing general skills (in particular, problem solving), but also has a crucial impact on general character traits, such as emotional stability, intellect, memory, alertness, and, above all, creativity….

      Creativity is not a skill, and it cannot be taught or learned. Creativity is a quality or characteristic that a person possesses….Viewed in these terms, it’s not simply that creativity can’t be learned; it’s also very difficult to influence. All that teachers can do is to provide a learning climate that offers psychological safety—a climate in which learners feel sufficiently secure—so that they have the courage and the confidence to do things and say things that, at first glance, perhaps seem odd or not completely right. In other words, teachers can provide an environment that encourages students to take risks, safe in the knowledge that their mistakes will be tolerated with understanding. We call this psychological safety.

      Memory is also a trait, so it, too, cannot be learned. This does not mean that it cannot be trained or improved, but such training needs to be highly focused and demands a huge investment in time. Consequently, this is not something that can be achieved “en passant” simply by learning to play chess.

      …According to Robinson, creativity is “the process of having original ideas that have value.” The key word here is “value.”

      Without knowledge and skills, it’s impossible—except by sheer luck—to create something of value. In fact, if you don’t have the requisite knowledge, you are not even in a position to assess the value of what you have done….

      …The idea that music can have a positive effect on executive functions is nothing new, although it’s still far from clear how long this effect lasts….

      And it doesn’t just have to be chess. Imagine that something else comes along—the use of classroom rituals, for example—that is proven to have a more significant impact on improved executive functions than music. If music is regarded purely as a means to an end rather than as an end in itself, this might even lead to its removal from the curriculum!...

      Apart from a huge fortune in the bank, what do Harry Potter author J. K. Rowling and Facebook guru Mark Zuckerberg have in common? They both learned Latin in schoo1. Various universities still use Latin names to add a certain cachet to the study of classics and classical languages. It is as though they seem to say that knowledge of Latin is the secret to success!...

      As far as the second question is concerned-can learning Latin help you to think better?-very little meaningful research has been conducted, largely because it’s so difficult to define what we mean by “thinking” to everyone’s satisfaction. Be that as it may, one study concluded that there was no relationship between the skills needed to learn Latin and the skills needed to learn other languages or mathematics. But that is more or less as far as the research goes at this stage. In other words, there is nothing to suggest a link between “learning Latin” and “better thinking.”

      If it’s unlikely that Latin makes it possible to learn other languages more easily, and if Thorndike’s theory suggests that far transfer is equally improbable, we can then reasonably ask the same question that we asked of music: Should Latin still be taught because of any intrinsic value of its own? Up to a point, the answer is yes. There are indications that learning Latin can lead to greater self-confidence and a deeper appreciation for other cultures, although this can just as easily be said for many other foreign languages, such as Chinese.

      The British classicist Mary Beard offers a more specific reason for learning Latin: it gives young people access to the literary tradition that forms the basis of Western culture. Again, this might well be the case, but it’s open to discussion as to whether that argument alone is sufficient to merit including Latin in the curriculum. In fact, all the “old” arguments in favor of Latin—that it has specific characteristics that make it easier to learn other languages and also improves a student’s general ability to think—no longer seem relevant or credible in this modern day and age.

      …This is not to say that there is no evidence whatsoever for far transfer, but it's very clear that the level of reliable evidence decreases in relation to the quality of the research: the better the research, the scanter the evidence….

The Origin of Federal Air Pollution Policy

[These excerpts are from an article by Jen Reidel in the March 2020 issue of The Science Teacher.]

      …On October 27, 1948, a thick smog covered Donora, a Pennsylvania city of 13,000 residents, most of whom worked in steel factories. Over four days, Donora experienced one of the worst air pollution disasters in American history. The smog caused nineteen deaths, negatively affected the health of over 1,440 people, and caused mild symptoms in another 4,470 residents. Factory officials convinced the United States Public Health Service (USPHS) to study the disaster. The initial USPHS report released in 1949 did not assign sole blame to the factories, but did highlight effects of air pollution and became a catalyst for federal attention.

      In December 1949, President Harry Truman directed his executive departments to co-sponsor a conference on air pollution. Truman’s request resulted in the federal government hosting the first ever United States Technical Conference on Air Pollution, May 3-5, 1950, assembling 500 experts representing a cross section of industries, who identified causes and impacts of pollution on Americans….Conference recommendations resulted in the passage of the Federal Air Pollution Control Act of 1955 providing money for scientific research on air pollution and lead to subsequent Clean Air Acts….

Transgender Perspectives in the Biology Classroom

[These excerpts are from an article by Elizabeth Hobbs in the March 2020 issue of The Science Teacher.]

      …Please be aware that I am not telling these stories to create the idea that trans people and/or students are victims, or to encourage a deficit mindset in teachers. I am telling these stories to create empathy and reliability so that teachers are moved to action….

      I verbally follow up with, “Everybody is different, everyone is unique, and everyone is struggling in their own way. It is important, no matter whatever else, that if a person looks or speaks differently, to always be kind. Always be kind. Treat them how you would want to be treated.” If you do not say it, students will not assume it….

      I point out gender assumptions during direct instruction. For example, most students have the misconception that larger mammals are male, and smaller ones are female. For many organisms, it is the opposite—females are larger than males—and we talk about reasons why during the ecology unit. At some point our cultural definitions of gender break down in the biological world.

      Some students simply want to “pass” (their gender identity and physical appearance match), as opposed to being “clocked” (physical appearance and gender expression are different to the observer). I never talk about a person’s gender expression or identity in class, and I police group interactions so that gender-complex students know they are safe.

      If I am unsure about a student’s gender, I ask, “What is your preferred/ affirmed pronoun?” Some preferred pronouns may be plural like “They/ Theirs”….I make sure to use their preferred pronoun and ensure that other students in the classroom use it Using the wrong pronoun is a microaggression—a comment or action that subtly and often unconsciously expresses a prejudiced attitude toward a member of a marginalized group. If you do misgender someone and they correct you, simply say “thank you for the correction, I will do better next time,” instead of apologizing. When someone hears constant apologies, they can infer that their gender identity is a weight or a burden….

      Students may or may not he changing clothes when they get to school or before they return home. Parents may be completely unaware of their child’s gender identity and expression, or they can he very supportive and well-informed. It is important to note that parents have gone, or arc going through, a grief process of losing the ideas they had for their child related to the sex that was assigned at birth.

      At some point parents can begin to see the new possibilities and the exciting reality of their child becoming their more-authentic self. I do make sure to keep parents up-to-date on any symptoms that are indicative of a change in mental health. Once I make contact, a parent will usually reveal what they know….

      One of the best questions I have been asked is: “What do you say to a colleague who refuses to use the right pronouns or name for a student?” My response is: “We teach all kinds of students we fundamentally disagree with, even bullies and bigots. As teachers in public school, we are required to meet students’ needs, not teachers’ pedagogical ideology. This student has made some specific requests and is asking nicely to be treated kindly by meeting chose requests.”

      …Many teachers might assume they only need to recognize that gender is a spectrum in the genetics unit, and only when there is a trans or gender-complex student in the class. Making trans and gender-complex students feel recognized and safe to be their authentic self is the main goal, but it is not the only goal. I fee] that every cis-gender (gender identity and gender expression culturally match sex assigned at birth) student also needs to hear and have adults model this recognition. In the future, whether it’s during the next class period, in the next year, at college, or in the workforce, students need a baseline of understanding. Then, they can correct others when misgendering occurs and help create a culture where violence and discrimination against trans people is simply past history.

      …Many teachers may be hesitant to explain these issues, answer questions, or incorporate these practices. However, people are dying because of trans discrimination. Twenty-eight people died in the United States in 2017 from violent assaults due to their gender identity….We cannot continue to teach while ignoring the damage our hidden curriculum does to the outside world. As biology teachers, the vast majority of us are advocates for environmental justice. It is an easy value and stance to advocate. But I am calling for social justice—the kind that recognizes and respects all students in the classroom.

Being Unique or Being Identical

[These excerpts are from an article by Paul G. Hewitt in the March 2020 issue of The Science Teacher.]

      When I was a child and my mother wished to be alone for a little while, she’d tell me to go out on the lawn and not to come back until I found a four-leaf clover. It was a fun activity, for they’re not as rare as people think. What nobody at the time knew was that if Mom had asked me to find two identical leaves, whether in groups of three or four, I would have been unsuccessful—no two clover leaves in the world are truly identical.

      …The same is true of the leaves of any plant, including trees! What many people don’t realize is that scientists have determined that in all the world, no two leaves of any plants are identical. Each is one of a kind—unique. This is astounding!...

      We see in photographs and videos huge numbers of penguins in Antarctica that appear to be identical. We don’t recognize differences within a species that would be obvious if we spent time with these fascinating birds. Similarly, when people first meet people of a different ethnicity, they see the others as all looking alike. This occurs both ways until a time of familiarity when differences become apparent.

      Distinguishing among penguin faces isn’t a problem for penguins who leave the colony for months in search of food; upon returning they clearly recognize their mates. VOice recognition helps, for each communicates with its own distinctive sound. Their calls to one another are recognized among the noise of many. Perhaps their sense of smell aids identification. In any event, each penguin is unique, with no two being exactly the same….

      One main reason for uniqueness has to do with physical composition. Leaves, faces, ladybugs, and other entities we see in nature are composed of constituent parts. Variations in the arrangement of these parts, however subtle, contribute to their differences. So we ask, are there any groups in which the members are identical—the same from one member to another? The answer is yes—the fundamental particles of physics, the most familiar of which is the electron!

      …Electrons are one group in the family of fundamental particles. Other fundamental particles include quarks, muons, and neutrinos, all of which are indistinguishable from one another—all are the same. The electrons that travel in wires, carry power to our homes, and vibrate in our smartphones are the same electrons as the electrons that surround the atomic nucleus. One electron is the same as any other electron: they are truly clones….

      Being unique is common in the macroworld. The structures of one-of-a-kind things are generally complex, having many structural parts. Things composed of dozens (or millions) of individual parts typically have so many ways of arranging the parts that no two arrangements will be identical. However, in the subatomic world where identical things exist, structures are simple, having no smaller parts.

      Under certain conditions, some composite particles—particles made up of smaller particles—can be identical as well. For example, hydrogen atoms in their ground state, or lowest energy state, are identical. But identical composite particles tend to be no more complex than a simple molecule. We don’t have to go very far up the complexity scale before being identical, although possible in principle, becomes less and less likely. So the uniqueness of every leaf, every face, and the pattern of spots on a ladybug can be understood in terms of the complexity of their structure at the atomic scale.

Genome Analyses Help Track Coronavirus’ Moves

[These excerpts are from an article by Kai Kupferschmidt in the 13 March 2020 issue of Science.]

      …They offer clues to how the virus, named SARS-CoV-2, is spreading and evolving. But because the sequences represent a tiny fraction of cases and show few telltale differences, they are easy to overinterpret….

      …is also studying the genome of SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2). But for now, scientists who analyze genomes can only make “suggestions”….

      The very first SARS-CoV-2 sequence, in early January, answered the most basic question about the disease: What pathogen is causing it? The genomes that followed were almost identical, suggesting the virus, which originated in an animal, had crossed into the human population just once. If it had jumped the species barrier multiple times, the first human cases would show more variety.

      Some diversity is now emerging. Over the length of its 30,000-base-pair genome, SARS-CoV-2 accumulates an average of about one to two mutations per month….

      …Still, the wealth of genomes is just a tiny sample of the more than 100,000 cases worldwide, and it's uneven. On 9 March, Chinese scientists uploaded 50 new genome sequences—some of them partial—from COVID-19 patients in Guangdong province; most previous ones were from Hubei province. But overall, less than half of the published genomes are from China, which accounts for 80% of all COVID-19 cases. And sequences from around the world are still very similar, which makes drawing firm conclusions hard….

      Scientists will also be scouring the genomic diversity for signs that the virus is getting more dangerous. There, too, caution is warranted….they fell into one of two distinct types, named S and L, distinguished by two mutations. Because 70% of sequenced SARS-CoV-2 genomes belong to L, the newer type, the authors concluded that this type has evolved to become more aggressive and to spread faster.

      …Some researchers have called for the paper to be retracted. “The claims made in it are clearly unfounded and risk spreading dangerous misinformation at a crucial time in the outbreak”….

      Most genomic changes don’t alter the behavior of the virus….The only way to confirm that a mutation has an effect is to study it in the lab and show, for instance, that it has become better at entering cells or transmitting….So far, the world has been spared that piece of bad news.

Do Us a Favor

[These excerpts are from an editorial by H. Holden Thorp in the 13 March 2020 issue of Science.]

      “Do me a favor, speed it up, speed it up." This is what U.S. President Donald Trump told the National Association of Counties Legislative Conference, recounting what he said to pharmaceutical executives about the progress toward a vaccine for severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2), the virus that causes coronavirus disease 2019 (COVID-19). Anthony Fauci, the long-time leader of the National Institute of Allergy and Infectious Diseases, has been telling the president repeatedly that developing the vaccine will take at least a year and a half—the same message conveyed by pharmaceutical executives. Apparently, Trump thought that simply repeating his request would change the outcome.

      China has rightfully taken criticism for squelching attempts by scientists to report information during the outbreak. Now, the United States government is doing similar things. Informing Fauci and other government scientists that they must clear all public comments with Vice President Mike Pence is unacceptable. This is not a time for someone who denies evolution, climate change, and the dangers of smoking to shape the public message. Thank goodness Fauci, Francis Collins [director of the U.S. National Institutes of Health (NIH)], and their colleagues across federal agencies are willing to soldier on and are gradually getting the message out.

      While scientists are trying to share facts about the epidemic, the administration either blocks those facts or restates them with contradictions. Transmission rates and death rates are not measurements that can be changed with will and an extroverted presentation. The administration has repeatedly said—as it did last week—that virus spread in the United States is contained, when it is clear from genomic evidence that community spread is occurring in Washington state and beyond. That kind of distortion and denial is dangerous and almost certainly contributed to the federal government’s sluggish response. After 3 years of debating whether the words of this administration matter, the words are now clearly a matter of life and death….

      I don’t expect politicians to know Maxwell’s equations for electromagnetism or the Diels-Alder chemical reaction (although I can dream). But you can’t insult science when you don’t like it and then suddenly insist on something that science can't give on demand. For the past 4 years, President Trump's budgets have made deep cuts to science, including cuts to funding for the Centers for Disease Control and Prevention and the NIH. With this administration’s disregard for science of the Environmental Protection Agency and the National Oceanic and Atmospheric Administration, and the stalled naming of a director for the Office of Science and Technology Policy—all to support political goals—the nation has had nearly 4 years of harming and ignoring science.

      Now, the president suddenly needs science. But the centuries spent elucidating fundamental principles that govern the natural world—evolution, gravity, quantum mechanics—involved laying the groundwork for knowing what we can and cannot do. The ways that scientists accumulate and analyze evidence, apply inductive reasoning, and subject findings to scrutiny by peers have been proven over the years to give rise to robust knowledge. These processes are being applied to the COVID-19 crisis through international collaboration at breakneck, unprecedented speed….But the same concepts that are used to describe nature are used to create new tools. So, asking for a vaccine and distorting the science at the same time are shockingly dissonant.

      A vaccine has to have a fundamental scientific basis. It has to be manufacturable. It has to be safe. This could take a year and a half—or much longer. Pharmaceutical executives have every incentive to get there quickly—they will be selling the vaccine after all—but thankfully, they also know that you can't break the laws of nature to get there.

      Maybe we should be happy. Three years ago, the president declared his skepticism of vaccines and tried to launch an antivaccine task force. Now he suddenly loves vaccines.

      But do us a favor, Mr. President. If you want something, start treating science and its principles with respect.

Education and Presidential Politics

[These excerpts are from an article by Maria Ferguson in the March 2020 issue of Phi Delta Kappan.]

      …Some candidates have offered plans to raise teacher pay and eliminate student debt. Others have promised to end standardized testing or make schools safer for students and teachers.

      But even for those with the best of intentions, making good on any large-scale education promise is not as simple as it sounds. Despite an annual education budget of just under $73 billion, presidents and their administrations have limited power over hot-button issues like teacher compensation, testing, and school safety. These issues make for excellent campaign fodder, but in reality, they are controlled by a large and often unwieldy cast of state and local leaders who may or may not care what the president thinks.

      Since President Donald Trump has never demonstrated much interest in or a compelling vision for public education, this is likely not something that keeps him up at night. Education Secretary Betsy DeVos, however, learned the limits of her power early on in the administration. Despite her zeal for deregulation and a choice-driven U.S. education system, DeVos has not transformed the operational landscape of public education in any significant way. All of her bu-get proposals and her efforts to garner support for privately funded “Education Freedom Scholarships” — which would allow students to attend private or religious schools by way of an annual tax credit — have garnered little support. And her efforts to paint U.S. public schools as flaming cauldrons of doom and despair have not really stoked a school choice revolution.

      Whatever impact DeVos has had comes in the form of damage, not progress. By rolling back several important Obama-era rules regarding student debt protections and civil rights enforcement, DeVos has eliminated some much-needed and hard-earned safeguards for students. This leaves the 2020 Democratic candidate with the challenging task of determining how to repair the damage….

      For both political and emotional reasons, the plight of teachers is always a theme in presidential elections. Teacher unions are a powerful force in politics, and their support can either buoy a candidate or drown them. At the same time, teachers represent a kind of hopeful selflessness that resonates with many Americans. Almost everyone has a favorite teacher who supported and believed in them, so when a candidate paints a picture of an increasingly beleaguered profession that is struggling to attract young talent, voters are eager to hear how they will change all that when they are president. Several candidates have laid out plans to increase teacher pay, especially for teachers in high-need, low-income schools; and some have talked about making more competitive teacher salaries a requirement for additional Title I funds.

      But perhaps the best rule of thumb for any candidate seeking teacher support would be to first do no harm, something recent education secretaries should also have considered….When it comes to teachers, presidential candidates should embrace the power of the bully pulpit to remind Americans how challenging the profession can be. Then they should take the time to learn which policies truly promote and support excellent teaching.…

      As the primaries continue, education issues, and whatever small controversies they may create, will fade into the background. This is the predictable arc of a presidential campaign. Education issues always surface in the early stages of the campaign as candidates scramble for support among key interest groups and state and local leaders….

      Presidential candidates quickly learn that voters care about education only up to a point, and sometimes it is easier and safer for them just to avoid the issue and focus on something else. This is unfortunate because even if education is, for the most part, a local issue, its impact on our country is tremendous. In recent years, we have seen what happens when our electorate does not have a full and accurate understanding of its own democracy. If our country is to maintain the principles of a free and fair society, a high-quality education should and must matter to everyone, no matter how complicated the issues are. As Americans we should expect no less from our candidates and ourselves.

The Landmark Case that Almost Never Was

[These excerpts are from a book review by Michael B. Gerrard in the 6 March 2020 issue of Science.]

      The U.S. Supreme Court’s 2007 decision in Massachusetts v. Environmental Protection Agency is widely seen as the most important U.S. environmental ruling of all time. But the suit, which led to a ruling that the Clean Air Act of 1970 empowered the U.S. Environmental Protection Agency (EPA) to regulate greenhouse gases, was almost never brought. Richard J. Lazarus’s wonderful new book, The Rule of Five, is the inside story of how this case came to be, how its lawyers struggled and fought over theories and roles, and how the late Justice John Paul Stevens patched together the five votes needed to secure a majority.

      Lazarus is ideally suited to tell this story. A law professor at Harvard, he has represented the government and environmental groups in 40 Supreme Court cases and presented oral argument in 14….

      The case in question was the brainchild of Joe Mendelson, a lawyer working for a little-known environmental group in Washington, D.C., called the International Center for Technology Assessment. In 1998, he drafted a 35-page petition to the EPA, arguing that it was the agency’s responsibility to regulate carbon dioxide and other greenhouse gases as pollutants, and put it in a drawer, awaiting the right time to file. A year later he decided that the time had come, but leaders of other environmental organizations pleaded and then pressured him not to file, thinking it would be better to wait for the expected ascension of a climate champion, Vice President Al Gore, to the presidency in January 2001. Mendelson filed anyway.

      The EPA sat on the petition until after the November 2000 election….

      …to everyone’s shock—the Supreme Court took the case….

      …In the months that followed, Justice Stevens found ways to persuade his colleague Anthony Kennedy to give him the crucial fifth vote needed to prevail.

      Lazarus walks readers through all of the procedural steps and legal theories that surrounded this case, using lucid prose that is easy for non-lawyers to follow. The book is a master class in how the Supreme Court works and, more broadly, how major cases navigate through the legal system.

      The Massachusetts v. EPA decision was the basis for almost all of the Obama administration’s actions on climate change, which included stricter regulations of emissions from motor vehicles and power plants. These actions, in turn, gave President Obama the legitimacy to press fellow world leaders to reach a landmark agreement on climate change in Paris in December 2015. However, in February 2016, the Supreme Court put Obama’s Clean Power Plan on hold, and President Trump has pressed to repeal it, to weaken the motor vehicle rule, and to pull the United States out of the Paris Agreement. As Lazarus rightly concludes, the most important legal decisions are made not in the courtroom, but at the ballot box.

Can China’s COVID-19 Strategy Work Elsewhere?

[These excerpts are from an article by Kai Kupferschmidt and Jon Cohen in the 6 March 2020 issue of Science.]

      Chinese hospitals overflowing with COVID-19 patients a few weeks ago now have empty beds. Trials of experimental drugs ca’n’t find enough eligible patients. And the number of new cases reported each day in China is dropping precipitously.

      These are some of the startling observations in a report released on 28 February by a team of 12 Chinese and 13 foreign scientists who toured five cities in China to study the state of the COVID-19 epidemic and the effectiveness of the country’s response. Even some on the team, organized jointly by the World Health Organization (WHO) and the Chinese government, say they were surprised….

      But the report is unequivocal. “China’s bold approach to contain the rapid spread of this new respiratory pathogen has changed the course of a rapidly escalat-ing and deadly epidemic,” it says….

      Members of the task force say the rest of the world should learn from China. But critics say the report failed to acknowledge the human rights costs of the most severe measures imposed by China’s authoritarian government: massive lockdowns and electronic surveillance of millions of people….Many also worry that a resurgence of the disease will occur after the country lifts some of its strictest control measures and restarts its economy, which has taken a huge hit.

      The report comes at a critical time in what many epidemiologists now consider a nascent pandemic. The number of affected countries is rising rapidly—it stood at 72 as Science went to press….

      But cases have plummeted in China. On 10 February, the first day of the mission, the country reported 2478 new cases. Two weeks later, when the foreign experts packed their bags, the daily number of new cases had dropped to 409. (On 3 March it had dropped further to 129 new cases, compared with 1848 in the rest of the world.) China’s epidemic appears to have peaked in late January, according to the report.

      Members of the team traveled to Beijing, Shenzhen, Guangzhou, Chengdu, and the hardest hit city, Wuhan. They visited hospitals, laboratories, companies, live animal markets, train stations, and local government offices….

      As part of the effort, Chinese scientists have compiled a massive data set that gives the best available picture of the disease. The mission report says about 80% of infected people had mild to moderate disease, marked by fever and a dry cough; 13.8% had severe symptoms; and 6.1% had life-threatening episodes of respiratory failure, septic shock, or organ failure. The case fatality rate was highest for people over age 80 (21.9%), and people who had heart disease, diabetes, or hypertension, but 3.8% overall. Children made up a mere 2.4% of the cases, and almost none was severely ill. People with mild and moderate illness took 2 weeks on average to recover.

      The report highlights how China achieved what many public health experts thought was impossible: containing the spread of a widely circulating respiratory virus….The most dramatic—and controversial—measure was the lockdown of Wuhan and nearby cities in Hubei province, putting at least 50 million people under a mandatory quarantine since 23 January. That has “effectively prevented further exportation of infected individuals to the rest of the country,” the report concludes. Most of China did not face such severe measures: People were asked, but not required, to quarantine themselves if they felt ill, and neighborhood leaders moni-tored their movements.

      Chinese authorities also built two dedicated hospitals in Wuhan in about 1 week, sent health care workers from all over China to Hubei, and launched an unprecedented effort to trace contacts of confirmed cases. In Wuhan alone, more than 1800 teams traced tens of thousands of contacts. Aggressive “social distancing” measures implemented in the entire country included canceling sporting events and shuttering theaters, schools, and businesses. Anyone who went outdoors had to wear a mask.

      Two widely used mobile phone apps, AliPay and WeChat—which in recent years have replaced cash in China—have helped enforce the restrictions, because they allow the government to keep track of people’s movements and even stop people with con-- firmed infections from traveling….Color codes on mobile phone screens—in which green, yellow, or red designate a person's health status—let guards at train stations and re. other checkpoints know who to let through.

      “As a consequence of all of these measures, public life is very reduced,” the report notes. But the measures did work. In the end, infected people rarely spread the virus to anyone except members of their own household….Once all the people living together were exposed, the virus had nowhere else to go and chains of transmission ended. “That’s how the epidemic truly came under control,” Leung says.

      It’s debatable how much of this could be done elsewhere….

      And the benefit may be short-lived. “There’s no question they suppressed the outbreak,” says Mike Osterholm….Reducing the peak number of cases buys a health system time to deal with later ones, public health experts say. But once the restrictions are lifted, “It’ll come roaring right back,” Osterholm predicts….

Making the Complex Work of Teaching Visible

[These excerpts are from an article by Pam Grossman in the March 2020 issue of Phi Delta Kappan.]

      …Unfortunately, things have not improved over the past two decades. The number of children facing challenges associated with living in poverty has only increased, making the work of teaching only more complex. Yet, despite the now widespread recognition that teachers represent the most important school-level influence on student achievement, teachers have continued to lose earning power; currently, according to economist Eric Hanushek, teachers are underpaid by at least 20%...

      Not surprisingly, college graduates are increasingly opting out of teaching as a career option. In the past 10 years, both the total enrollment in teacher education programs and the number of individuals completing a preparation program dropped by almost a third; in some states, such as Pennsylvania, enrollments dropped by more than 50%....Black male teachers still represent only 2% of the teaching force, even as evidence mounts that having a teacher of the same race supports student achievement….

      So how do we turn this tide? How might re-envisioning the narrative of teaching as a profession help restore the image of teaching as both intellectual and relational work, central to achieving equitable opportunities for young people and critical to the future of our fractured society?

      …The move toward requiring master’s degrees for teachers, the definition of pedagogical content knowledge, and the creation of the National Board for Professional Teaching Standards in the 1980s and 1990s were all explicit efforts to professionalize teaching by following the lead of the high-status fields of medicine, law, and architecture.

      However, critics have argued that teaching has few of the hallmarks of a profession — a specialized knowledge base, the ability to practice autonomously, and the right to control entry into the field. Others have argued against the very idea of professionalization, preferring to emphasize the artisanal nature of teaching as more a result of individual craft rather than collective expertise. Still others argue that the very idea of professionalism creates distance between teachers and the people they serve and may undermine the relational nature of teaching practice. Indeed, these sociological definitions of professionalism focus mainly on the organizational structures that define an occupation, and they say little about the work that people do.

      Recent decades have also seen the emergence of a countertrend, focusing on the creation of professional networks that put teachers and teaching at the center of efforts to professionalize teaching….

      …All too often, teachers have been portrayed and even valorized as isolated artisans, each doing their own thing in the classroom. New teachers are urged to create their own materials, chart their own paths, and reject professional education in favor of learning from their own experience.

      The assumption that teaching is highly individualistic has often been used to resist efforts at specifying — or, some fear, prescribing or oversimplifying — what accomplished teachers actually do in the classroom….

      But, some might argue, if we try to specify precisely what accomplished teachers do, don’t we risk framing instruction as a purely technical practice — a series of moves and behaviors — ignoring the relational aspects of the work? To the contrary, the more closely we describe successful teaching, the more clear it becomes that the work of teaching is deeply interpersonal. To engage students in learning, teachers need to build positive relationships with them….And building such relationships —across cultural and racial differences in crowded classrooms with students who have not chosen to be in a teachers’ class — is complex and difficult work that requires knowledge, skill, judgment, and the negotiation of personal identity. Highlighting this feature of teachers' work makes it more, rather than less, visible….

Carbon-Cutting Cuds

[These excerpts are from an article by Jennifer Walter in the March/April 2020 issue of Discover.]

      …The cows’ special diet includes small portions of a red seaweed called Asparagopsis armata. It contains a compound called bromoform, which inhibits the action of an enzyme that produces methane during the cows’ digestion. Less methane means less burping. And, on a global scale, less burping could mean slowing down climate change….

      The EPA estimates that methane from livestock, especially cows and other ruminants (cud-chewers) like sheep, makes up almost one-third of agricultural emissions in the U.S. And although agriculture accounts for a smaller percentage of total greenhouse gas production than sectors like transportation and energy, it produces more methane, which warms the Earth up to 86 times as much as CO2.

      When cows eat, they burp food back, up, chew it as cud and swallow it again to make it easier to digest. But during that process, which cows repeat dozens of times throughout the day, an enzyme made by microorganisms in their gut produces methane as a byproduct.

      …it wasn’t until 2016 that researchers in Australia finally homed in on a strand called Asparagopsis taxiformis. In lab models, they found that grass feed that was 2 percent seaweed could cut methane emissions by nearly 99 percent….But questions remained about the seaweed's effectiveness in actual cow stomachs.

      …When they tested a similar species, A. armata, at low levels in the diets of lactating dairy cows, they found that a diet of just 0.5 percent seaweed led to a 26-percent decrease in methane A 1-percent seaweed diet produced 67 percent less methane….

      Researchers still need to ensure the burp-curbing compounds, which are sensitive to heat and light, will be shelf-stable and remain effective in real-world applications. And even if the seaweed succeeds, methane from livestock account for just 5 percent of greenhouse gas production in the U.S., so the overall picture won’t improve much….

An Elegy for Cash

[These excerpts are from an article by Mike Orcutt in the March/April 2020 issue of MIT Technology Review.]

      …This is a feature of physical cash that payment cards and apps do not have: freedom. Called “bearer instruments,” banknotes and coins are presumed to be owned by whoever holds them. We can use them to transact with another person without a third party getting in the way. Companies cannot build advertising profiles or credit ratings out of our data, and governments cannot track our spending or our movements….

      We shouldn’t take this freedom for granted. Much of our commerce now happens online. It relies on banks and financial technology companies to serve as middlemen. Transactions are going digital in the physical world, too: electronic payment tools, from debit cards to Apple Pay to Alipay, are increasingly replacing cash. While notes and coins remain popular in many countries, including the US, Japan, and Germany, in others they are nearing obsolescence.

      This trend has civil liberties groups worried….

      However, there’s no evidence that any governments are even thinking about deploying tools like this. And regardless, can any government—even Sweden's—really be trusted to blind itself?

      That’s wishful thinking….While you may trust your government or think you've got nothing to hide, that might not always remain true. Politics evolves, governments get pushed out by elections or other events, what constitutes a “crime” changes, and civil liberties are not guaranteed….

      But in some places people just need something that works, however imperfectly. Take Venezuela. Cash in the crisis-ridden country is scarce, and the Venezuelan bolivar is constantly losing value to hyperinflation. Many Venezuelans seek refuge in US dollars, storing them under the proverbial (and literal) mattress, but that also makes them vulnerable to thieves.

      What many people want is access to stable cash in digital form, and there’s no easy way to get that….Owing to government-imposed capital controls, Venezuelan banks have largely been cut off from foreign banks….

      How big a problem is this? That depends on where you live, how much you trust your government and your fellow citizens, and why you wish to use cash. And if you’d rather keep that to yourself, you’re in luck. For now.

Air Pollution’s Systemic Effects

[These excerpts are from an article by Jonathan Shaw in the March/April 2020 issue of Harvard Magazine.]

      Breathing fine particles suspended in the air is harmful for everyone—and can kill those with cardiovascular or respiratory vulnerabilities, a fact known since the 1990s. Now a study of 95 million Medicare hospitaliation claims from 2000 to 2012 links as many as 12 additional diseases, including kidney failure, urinary tract and blood infections, and fluid and electrolyte disorders, to such fine-particle air pollution for the first time. The research demonstrates that even small, short-term increases in exposure can be harmful to health, and quantifies the economic impact of the resulting hospitalizations and lives lost.

      Fine particles (known as PM2.5 because they are smaller than 2.5 microns in diameter) can slip past the human respiratory system’s copious mucosal defenses in the nose and upper airways. These tiny byproducts of combustion, principally of fossil fuels such as coal and oil, land in the thin-membraned alveolar sacs deep in the lungs where oxygen exchange occurs. From there, they can pass into the blood. But the full extent of the systemic harm they cause is not well understood….

      To do so, the researchers used a “big-data” approach, aligning Medicare-patient hospital admissions by time and geography with known levels of PM2.5 pollution on the previous day. That information was modeled using satellite and temperature data, and verified with actual measurements from thousands of ground-based monitoring stations….

      …satellite data for air pollution is provided in one-square-kilometer grids, whereas temperature and weather data cover areas of 32 square kilometers. And patient zip code records must be aligned with both these measures. Overcoming such hurdles so that the data sources can all talk to each other is challenging, but worthwhile….

      To the known effects on the cardiovascular, respiratory, and nervous systems, the team’s work has added pathologies of the blood, gut, skin, and kidney….

      The research demonstrates that every microgram-per-cubic-meter increase in PM2.5 within a 24-hour period has an incremental effect on human health. Even when starting from zero (perfectly clean air), each such increase of one microgram in concentration was associated with an annual increase of 634 deaths and 5,692 hospitalizations, as well as 32,314 patient-days in hospital. In the United States, such increases in pollution occur on more than 122 days a year in every geographic region. In lay terms…this represents “one additional hospitalization per day for every zip code for half of the year.” These data correspond to $100 million in annual inpatient and post-acute care costs, and an estimated $6.5 billion in lost value of human life. In the United States, where fine particle pollution began rising again in 2016 after a long-term decline, Environmental Protection Agency regulations specify that exposures greater than 35 micrograms of PM2.5 or less in a 24-hour period are unhealthy. (The target for annual, or long-term, limit of exposure, averaged over three years, is 12 micrograms per cubic meter.)

      …these findings understate the economic impact of fine-par-ticle pollution in several ways. The study captured only effects that led to hospitalization, and not prior visits to a doctor or the costs of previously prescribed medication, or costs after discharge (including readmission, outpatient, and drug costs). And it captured only fee-for-service patients, not those covered in HMOs. It didn’t capture effects on mental health, or in fact “any encounter with the healthcare system that did not lead to a billing record in the hospital.” And it did not capture data for any-Lone under the age of 65….

      Older people may be more vulnerable to air pollution than young people with eakhy immune systems, …but everyone is affected….

      …there is another common benefit to controlling PM2.5 that is often overlooked in discussions of air pollution: “There is a direct linkage between the sources of fine particulate matter and the sources of greenhouse gases. Most are the same.”

Healthy Plate, Healthy Planet

[These excerpts are from an article by Jacob Sweet in the March/April 2020 issue of Harvard Magazine.]

      …In 1980, seven years before that first KFC, the prevalence of Type 2 (adult onset) diabetes in China was less than 1 percent of the population. In 2001, that had risen to 5.5 percent. Now, with an estimated 116 million diabetics in the country, the number is 12 percent—and still rising.

      …It’s one thing to know that among large populations, heavy consumers of red meat are at a greater risk of Type 2 diabetes, cardiovascular disease, certain cancers, and premature death. It's another to know how red meat, compared to plant proteins like nuts and legumes, increases blood levels of low-density lipoprotein cholesterol, which clogs arteries and can lead to atherosclerotic cardiovascular disease….

      Hu was one of the first in his field to stress the potential importance of metabolomics—the study of the chemical by-products specific cellular processes leave behind—which may allow for better diet measurements and earlier disease-risk identification When media sources need an expert on any nutrition topic, Hu often receives a call. The New York Times has asked him to comment on the health impacts of eggs, fish, red meat, walnuts, the Mediterranean diet, calorie restriction, carbohydrate as a replacement for fat, fats as a replacement for carbohydrates, and instant noodles.

      Right now, no one study or topic is as pressing to Hu as the intersection of three threats: obesity, undernutrition, and climate change. Of the seven and a half billion people in the world, about two billion are overweight, and two billion more are undernour-ished. "Both overnutrition and undernutrition are affected by climate change….When the temperature rises—when carbon dioxide increases—that can actually reduce the amount of zinc, iron, protein, and other nutrients in crops like rice or wheat...and that can further exacerbate the problem of undernutrition in the poor regions of the world.”…Animal agriculture, the second-largest contributor of human-made greenhouse gas (GHG) emissions worsens the problem.

      An increase in food production during the past 50 years has helped decrease world hunger and increase life expectancy. But a shift to “Western-style dietary patterns”—high in calories, highly processed foods, and meat—is unsustainable…because it damages not only individual and population health, but also the environment.

      Since 1963, global meat consumption has risen by 62 percent. In developing nations, the increase has been about five times that, with China increasing its meat consumption nine-fold. The more meat, the greater the cost to the environment. Food production is the world’s largest cause of biodiversity loss, responsible for 80 percent of deforestation, more than 70 percent of fresh-water use, and 30 percent of human-generated GHG emissions….Animal products play an outsized role: meat and dairy production accounts for more than 8o percent of the food sector's GHG emissions, and requires n times more fossil fuels to supply a single unit of protein than grain-based sources….Red meat is especially inefficient. Producing 50 grams of beef protein yields 17.7 kilograms of carbon dioxide on average. For tofu, beans, and nuts, it’s 1.0, .4, and .1 kilograms, respectively.

      If eating red meat were clearly healthy, nutrition scientists might face a predicament. But…red meat—and processed red meat in particular—isn’t….

      …Contrary to popular belief,…plant-based diets do not have to be vegan or vegetarian. For most people, complete elimination of meat or animal products is unrealistic and not necessary for improving health….Hu also pushes for public-health strategies to make healthier diets cheaper and more accessible—from soda taxes and agricultural subsidies to fast-food marketing and zoning restrictions that could make junk food less appealing and ubiquitous, to public-education campaigns and reforms to the Supplemental Nutrition Assistance Program (formerly known as food stamps).

      …Just as observational studies made it clear that smoking increased disease risk, he believes that obesity, chronic disease, and climate change present challenges too severe to be pushed to the future….

When Life Meets Research

[These excerpts are from aa book review by Janet Rossant in the 28 February 2020 issue of Science.]

      …Developmental biologists have studied the progression of the fertilized mammalian egg through its early cleavage divisions to the formation of the 100-cell blastocyst for many years. Such studies have suggested that there is a gradual segregation of cell fate influenced by cell polarity, cell position (inside or outside), and mechanical signals and that the embryo is able to regulate for loss, gain, or rearrangement of cells right up to the blastocyst stage. However, none of these studies really addressed the question of whether there might be asymmetries in the egg or early embryo that could bias later cell fate.

      …She describes her work on defin-ing early asymmetries in the mouse embryo and their role in informing later development in careful detail, recounting how she used tools such as cell marking, live imaging, and gene manipulation to determine that early blastomeres show a bias toward different regions and cell types of the blastocyst. However, other researchers—using different techniques—found less evidence for early differences, leading to some vigorous debates, as described in the book.

      This controversy compelled researchers who had set aside work on the early embryo to reenter the fray, bringing new tools and ideas. And, although it is still not clear what initiates asymmetries after fertilization, it is increasingly clear that by the four-cell stage, there are differences in chromatin modification and transcription factor activity among the cells that, while not permanently specifying cell fate, may bias I their future lineage contributions.

What Is Killing the Monarchs?

[These excerpts are from an article by Gabriel Popkin in the March 2020 issue of Scientific American.]

      …That forest is the start of a remarkable annual migration that sends monarchs as far north as Canada during the summer and brings them back to Mexico every winter….Farmers were dousing corn and soybean fields there with the weed killer Roundup to wipe out many nuisance plants. But the chemical also kills a plant precious to the monarchs: milkweed, on which adult butterflies lay the eggs and the only plant that monarch caterpillars eat….Roundup was imperiling the great monarch butterfly migration.'

      The public and many monarch scientists were galvanized by the idea. It made sense—a major food all worried about source was vanishing just as Mexico’s butterfly population was crashing. In the winter of Oberhauser’s visit, there had been about 300 million butterflies, but just over a decade later there were fewer than 100 million. The remedy, Oberhauser and others said, was to plant milkweed in large amounts to make up for the losses….Environmental groups peti-tioned the U.S. Fish and Wildlife Service to list the monarch butterfly, Danaus plexippus plexippus, as a threatened species to give it more habitat protection.

      But since then, some scientific cracks have emerged in the milkweed case. Monarch censuses taken in the U.S. both during and after the summer breeding season showed no steady decline, even as Mexican numbers plummeted. And many Mexican butterflies came from U.S. areas without many Roundup-soaked crop fields, other data suggested. Skeptical scientists asserted that the insects were breeding fine in northern climes but that something was taking them out on their way to Mexico….

      The identity of that something, however, remains an elusive and troubling mystery. Some data have suggest-ed that landscapes have lost nectar-giving plants that adult monarchs feed on during their southward journey and that the all-important forests at the end of the migratory route have been degraded. Scientists have also speculated that a parasite infection might be cut-ting down the migrants. (A smaller monarch population that winters on the California coast has also crashed recently. Entomologists are concerned about this group, but its habitat does not overlap with that of the eastern population, so scientists think the causes of this crash are probably different.)

      Virtually everyone agrees that overall, despite spikes and dips from one year to the next, the winter population in Mexico has been heading down for most of the past three decades. That is not good news for the monarchs. What to do about it, though, depends on the cause….But the other evidence adds confusing and complex twists to what once seemed like a straightforward story with a ready-made villain. That means helping the insects has become more complicated, too.

      …female monarchs alight on more than 70 species of milkweed plants (genus Asclepias) to feed and to lay eggs. One adult female can lay up to 500 eggs. When that job is done, she dies. From her eggs hatch caterpillars that turn into butterflies; the cycle repeats four to five times during a year.

      Monarchs that overwinter in Mexico fly north and lay eggs near the Texas border in the spring. Their offspring live two to six weeks and spawn generations that move to the Midwest and South and ultimately all the way into the Great Lakes states, New England and Canada. As the days shorten in the fall, the last butterfly generation, dubbed the “super generation,” appears. These insects can live as long as eight months because their metabolism slows down and they do not spend precious energy on reproduction. Instead they travel south—all the way from higher latitudes to Mexico, covering up to 160 kilometers in a day. By December the insects that have survived the trip are huddled on Mexican firs. They live there until early spring, when they begin their own journey north, and their children continue the odyssey.

      In the late 1970s, after a long search, biologists discovered the tiny mountainside forests where monarchs were overwintering in Mexico….

      …Agricultural chemical company Monsanto had engineered corn and soy plants with a gene that allowed them to survive exposure to the herbicide glyphosate, better known by its trade name, Roundup. That meant Roundup could be sprayed liberally, leaving money-making crops unharmed while killing nearly everything else in a field. For farmers, “Roundup Ready” corn and soy were boons. For other plants that took up space among harvest rows, they were a death sentence. By 2007 nearly all the farmed soy and more than half of the corn in the U.S. were Roundup Ready.

      …between 1999 and 2010 the overall number of Midwestern milkweed plants had declined by 58 percent….within that time span, overwintering monarch populations had fallen steeply. In fact, during the winter of 2009-2010 the occupied area of Mexican forest decreased to less than half of what it had been the previous year and dipped below two hectares for the first time since record keeping began in the early 1990s. The link between the two trends seemed inescapable….

      …But the monarch butterfly has a special place in the hearts of people in three North American nations. The insect's bright-orange color and large size, the gentle loops of its flight and, most of all, its spectacular migration have made the monarch a much loved celebrity.

      And the story had a bad guy that the public was already primed to hate. Roundup's manufacturer, Monsanto (now part of the conglomerate Bayer), embodied many people's fears about genetic engineering and corporate control of agriculture. So the idea that Monsanto’s flagship product was killing America’s flag-ship insect made big news….

      But even as the wilkweed limitation hypothesis gained public support, some scientists suspected it was being built on a flimsy foundation….the numbers did not show a steady decline but bounced up and down year to year, as is typical of insect populations.

      …Although there may still be enough total milkweed across North America to support a healthy monarch population…the use of Roundup may have shifted the milkweed distribution in ways that could do harm. If the chemical’s effect has been to concentrate milkweed plants in smaller areas outside farm fields, female monarchs may have to lay all their eggs closer to one another, forcing more caterpillars to compete for the same food and stressing the population….

      Then, in the spring of 2019, a separate team of researchers found two likely suspects: harm to nectar-producing plants along the migratory route and changes in forest density in Mexico….It was the first investigation to divide the winter monarchs into their 19 individual colonies rather than lumping all the forested areas together. Colonies with more dense forest cover, it turned out, nosted more butterflies….

      …When the southern U.S. was greener in the fall, more monarchs arrived in Mexico; when it was browner, as happened during droughts, healthier plants produced more nectar capable of sustaining migrating monarchs….

      The new evidence could indicate that there may be multiple culprits in the monarch decline, not just one….

      All sides agree that helping the monarch cannot wait until the science is settled. The area of Mexican forest occupied by monarchs plummeted in 2013 to a spot barely larger than a standard soccer pitch, a record low. Although the migratory population has rebounded somewhat since then, most researchers still view its status as precarious. The U.S. Fish and Wildlife Service says it will rule on the endangered species petition later this year….

Silky Seeds

[These excerpts are from an article by David L. Chandler in the March/April 2020 issue of MIT News.]

      Coating seeds with specially treated silk could make it possible to grow crops in otherwise unproductive soils, according to new research at MIT.

      The silk, which protects the seeds from soil that would normally be too salty, also contains a kind of bacteria that naturally produce a nitrogen fertilizer. Lab tests have shown that the seeds grow successfully in these salty conditions.

      …Such fertilizers use microbes that convert nitrogen from the air into a form plants can readily take up. They avoid the drawbacks of conventional nitrogen fertilizers, which he says may degrade soil quality and are very energy intensive to produce.

      Although nitrogen-fixing bacteria occur naturally in soils around the world, they are very hard to preserve outside their native environment. But…mixing them with silk derived from silkworm cocoons…and a type of sugar did the trick. In practice, the treated silk could be simple to apply to seeds by either dipping or spray coating, they say. Legumes such as beans and chickpeas have been the focus of the research so far, but it may be possible to adapt the technique to other crops.

      The researchers are now working on coatings that could also make seeds more resistant to drought. They plan outdoor tests in Morocco this year.

Potato Signals

[These excerpts are from an article by Priyanka Runwal in the March 2020 issue of Scientific American.]

      When nibbled, the leaves of one type of sweet potato release a strong-smelling chemical warning that prompts other leaves—on the same plant and those nearby—to produce defensive proteins that make them hard to digest. New research tracks this odorous alert system.

      …Other plants have chemical warning systems that prompt neighbors to prepare for attack, but individual leaves often wait to manufacture defensive compounds until bitten themselves. But this plant’s leaves produce the compound immediately when neighbors are bitten….

      To investigate this response, Mithofer and his colleagues released caterpillars on the pest-resistant sweet potato strain Tainong (TN) 57 and its more susceptible cous-in TN66, both native to Taiwan. Each “exhaled” at least 40 chemicals when attacked, but the TN57 leaves released twice the amount of a compound called DMNT, also found in other plant-defense responses.

      Next, the scientists placed a healthy TN57 plant in a closed glass tank with one whose leaves had been pierced with tweezers. Within 24 hours high levels of a protein called sporamin formed in both plants’ uninjured leaves. Sporamin, also found in sweet potato tubers themselves, is what makes it difficult for humans to digest them un-cooked—and it causes trouble in insect guts, too. When researchers released synthesized DMNT into a tank with healthy plants, the. leaves again readily formed sporamin….

What’s Missing from Medical Training

[These excerpts are from an editorial by Erin Paquette and Angira Patel in the August 2020 issue of Scientific American.]

      …many physicians, ourselves included, think social issues should be at the heart of medical education.

      Formal medical school typically takes four years, followed by several years of residency and often a fellowship, and during that short time students have a myriad of competing requirements. They must learn complex biological and chemical pathways that explain disease and health. They must be educated on how to read the scientific literature and apply it to their patients. They must master many therapies and know how to adapt them to patients’ varied disease states. On top of all this, they must learn to communicate effectively and compassionately with patients and colleagues.

      Being a good doctor also demands that we understand the reasons behind poor health. Our mission is not simply to diagnose, manage and treat. Physicians should act to prevent the root causes of illness and improve well-being….

      Worldwide, life expectancy and health are directly linked with national spending on public health programs. The U.S., despite spending more on the treatment of individuals, ranks lower in life expectancy than nations that have similar overall health expenses -but choose to direct funds to population-level interventions. Our own experiences underlie our perspective that teaching this is important. Practicing in Chicago, where people living only miles apart have different life expectancies—where black mothers disproportionately experience poor obstetrical outcomes and premature births as compared with their white counterparts, where residents name stress, drug abuse and depression as the greatest health threats to local children—we see the impact of social determinants of health on our patients. For individual patients, research tells us that high levels of toxic stress and adverse experiences create epigenetic changes that raise the risk of problems such as heart disease….

      We work daily to understand the best ways to teach medical students about social determinants of health. We offer classes on health equity and advocacy designed to place medicine in its larger social context. We lead bioethics curricula that guide students in making ethical decisions while incorporating principles of social justice, public health and population health. And we work with groups…where the goal is to find and share best practices. It is through this kind of medical education and holistic understanding of systems that physicians begin to think about the total set of circumstances that brought the patient in front of us. As doctors, scientists and community members, what we want most is to prevent it from happening again.

      Physicians are trained to tackle problems at their root. System-and structural-level social issues are also drivers of poor health, and it is our duty to address them. Rather than veering out of this lane, we should find ways to engage students here without sacrificing education in other areas. Medical training must evolve to produce doctors who are able to treat the individual but also understand the larger influencers of health….

Strange Bedfellows for Human Ancestors

[These excerpts are from an article by Ann Gibbons in the 21 February 2020 issue of Science.]

      The story of human evolution is full of ancient trysts. Genes from fossils have shown that the ancestors of many living people mated with Neanderthals and with Denisovans, a mysterious group of extinct humans who lived in Asia. Now, a flurry of papers suggests the ancestors of all three groups mixed at least twice with even older “ghost” lineages of unknown extinct hominins. One candidate partner: Homo erectus, an early human who left Africa by 1.8 million years ago, spread around the world, and could have mated with later waves of human ancestors.

      The new genomic studies rely on complex models of inheritance and population mixing, and they have many uncertainties, not least the precise identities of our ancestors’ strange bedfellows and when and where the encounters took place. But, taken together, they build a strong case that even before modem humans left Africa, it was not uncommon for different human ances-tors to meet and mate….

      The gold standard for detecting interbreeding with archaic humans is to sequence ancient DNA from fossils of the archaic group, then look for traces of it in modern genomes. Researchers have done just that with Neanderthal and Denisovan genomes up to 200,000 years old from Eurasia. But no one has been able to extract full genomes from more ancient human ancestors. So population geneticists have developed statistical tools to find unusually ancient DNA in genomes of living people. After almost a decade of tantalizing but unproven sightings, several teams now seem to be converging on at least two distinct episodes of Lvery ancient interbreeding.

      …the ancestors of Neanderthals and Denisovans—whom they call Neandersovans — interbred with a “super-archaic” population that separated from other humans about 2 million years ago. Likely candidates include early members of our genus, such as H. erectus or one of its contemporaries. The mixing likely happened outside of Africa, because that’s where both Neanderthals and Denisovans emerged, and it could have taken place at least 600,000 years ago.

      …One challenge is reconciling it with new results from other researchers that show modern human ancestors mixed with super-archaic groups more recently, in Africa….

      This ghost species may have been late H. erectus, H. heidelbergensis, or a close relative. One or more late-surviving members of this ancient group met and mated with the ancestors of living Africans sometime in the past 124,000 years, the modern genomes suggest….

      Today, H. sapiens doesn’t have the possibility of quickly grabbing a load of diversity by mating with another group: For perhaps the first time in our history, we’re the only humans on the planet. It’s another reason to miss our extinct cousins, says population geneticist Carina Schlebusch of Uppsala University. “To have such a large densely spread species with ... so little ge-netic diversity ... is a dangerous situation,” hshe says.

The Art of Misleading the Public

[These excerpts are from a book review by Sheril Kirshenbaum in the 14 February 2020 issue of Science.]

      At the dawn of a new decade and in a pivotal election year, we face unprecedented challenges that threaten the environment, public health, and security. Meanwhile, dark money is being funneled through powerful lobbyists, plaguing the process of enacting informed, evidence-based policies. David Michaels’s new book, The Triumph of Doubt, is a tour de force that examines how frequently, and easily, science has been manipulated to discredit expertise and accountability on issues ranging from obesity and concussions to opioids and climate change….

      His book offers account after account of unethical bad actors working against the public good on issues ranging from asbestos to climate change. Powerful firms and individuals seeking personal gain repeat the tactics of a well-worn playbook of denial and misdirection proven effective by Big Tobacco more than 50 years ago. Michaels pulls no punches, naming the corporations and people responsible for fraud, deception, and even what he terms “climate terrorism.” He reveals the dirty ways that industries have succeeded at shaping their own narratives regarding safety and health by producing articles and diversions designed to deny and distort science while confusing the public.

      When a Boston University brain study found that 110 of 111 National Football League (NFL) players' brains showed pathologies consistent with the rare disease chronic traumatic encephalopathy (CIE), the NFL hired its own conflicted scientists to counter and discredit these troubling findings. When reports from the International Agency for Research on Cancer, the U.S. National Toxicology Program, and the World Health Organization independently linked alcohol consumption to certain cancers, the alcoholic beverage industry claimed that these associations were not real and doubled down on its messaging that moderate drinking is good for us. When the opioid epidemic hit the United States, ravaging families and communities, well-documented evidence suggests that drug companies suppressed research and misrepresented the clear science demonstrating that opioids are addictive and easily abused.

      What is most striking in The Triumph of Doubt is that Michaels is not merely reporting on how corporations and industries manufacture uncertainty. Rather, he provides an insider’s perspective on the machinations taking place in the nation's capital, in courtrooms, and across the country. He offers firsthand accounts of where and when science is for sale, instances in which data have been reanalyzed to promote uncertainty and misrepresent findings, as well as the establishment of groups that advance corporate interests while hiding their involvement….

Life without Ice

[These excerpts are from an editorial by Mark C. Urban in the 14 February 2020 issue of Science.]

      For millions of years, Arctic sea ice has expanded and retracted in a rhythmic dance with the summer sun. Humans evolved in this icy world, and civilization relied on it for climatic, ecological, and political stability. But the world creeps ever closer to a future without ice. Last year, new reports documented how record Arctic warmth is rapidly eroding sea ice….

      …last year’s minimum Arctic sea ice extent was the second lowest on record….2019 ended with the second lowest Arctic sea ice volume on record. The sea ice is now 40% smaller than it was 40 years ago, and the remaining ice is younger, thinner, and more temporary. Arctic summers could become mostly ice-free in 30 years, and possibly sooner if current trends continue.

      Although most people have never seen the sea ice, its effects are never far away. By reflecting sunlight, Arctic ice acts as Earth’s air conditioner. Once dark water replaces brilliant ice, Earth could warm substantially, equivalent to the warming triggered by the additional release of a trillion tons of carbon dioxide into the atmosphere. The ice also determines who gets rain. Loss of Arctic sea ice can make it rain in Spain, dry out Scandinavian hydropower, and set California ablaze. And declining sea ice threatens wildlife, from the iconic polar bear to algae that grow beneath the sea ice, supporting an abundance of marine life.

      Unfortunately, the sea ice conceals not just algae, but also 90 billion barrels of oil and 1.7 trillion cubic feet of natural gas that neighboring countries would like to claim. If extracted and burned, these fossil fuels would exacerbate climate change greatly. Arctic nations are now racing to find undersea evidence that extends their continental shelves poleward, which would allow them to control these resources and substantiate military claims. If conflicts over Arctic ownership intensify, the thawing ice cap could spark a new—more aptly named—cold war….

      Sixty years later, we must now save the Arctic….

What If Aging Were a Disease?

[These excerpts are from an article by David Adam in the September/October 2019 issue of MIT Technology Review.]

      …Since ancient times, aging has been viewed as simply inevitable, unstoppable, nature’s way. “Natural causes” have long been blamed for deaths among the old, even if they died of a recognized pathological condition. The medical writer Galen argued back in the second century AD that aging is a natural process.

      His view, the acceptance that one can die simply of old age, has dominated ever since. We think of aging as the accumulation of all the other conditions that get more common as we get older—cancer, dementia, physical frailty. All that tells us, though, is that we’re going to sicken and die; it doesn’t give us a way to change it….

      But a growing number of scientists are questioning our basic conception of aging. What if you could challenge your death—or even prevent it altogether? What if the panoply of diseases that strike us in old age are symptoms, not causes? What would change if we classified aging itself as the disease?

      …Medicine…should view aging not as a natural consequence of growing older, but as a condition in and of itself. Old age…is simply a pathology—and, like all pathologies, can be successfully treated. If we labeled aging differently, it would give us a far greater ability to tackle it in itself, rather than just treating the diseases that accompany it….

      It is a subtle shift, but one with big implications. How disease is classified and viewed by public health groups such as the World Health Organization (WHO) helps set priorities for governments and those who control funds. Regulators, including the US Food and Drug Administration (FDA), have strict rules that guide what conditions a drug can be licensed to act on, and so what conditions it can be prescribed and sold for. Today aging isn’t on the list….

      Nature suggests that endless life might not be inconceivable. Most famously, perhaps, the bristlecone pine trees of North America are considered biologically immortal. They can die—chopped down by an ax or zapped by a lightning bolt—but left undisturbed, they typically won’t simply fall over because they get old. Some are reckoned to be 5,000 years young; age, quite literally, does not wither them. Their secret remains a mystery. Other species appear to show signs of biological immortality as well, including some sea creatures.

      Such observations have led many to contend that life span can be dramatically extended with the right interventions. But in 2016, a high-profile study published in Nature argued that human life has a hard limit of about 115 years. This estimate is based on global demographic data showing that improvements in survival with age tend to decline after 100, and that the record for human longevity hasn't increased since the 1990s. Other researchers have disputed the way the analysis was done….

      Whether or not they believe in either the disease hypothesis or maximum life spans, most experts agree that something has to change in the way we deal with aging….

      One thing that may underlie the growing calls to reclassify aging as a disease is a shift in social attitudes….

      One promising treatment is metformin. It’s a common diabetes drug that has been around for many years, but animal studies suggest it could also protect against frailty, Alzheimer’s, and cancer. Giving it to healthy people might help delay aging, but without official guidance doctors are reluctant to prescribe it that way….

      Metformin is one of a broader class of drugs called mTOR inhibitors. These interfere with a cell protein involved in division and growth. By turning the protein’s activity down, scientists think they can mimic the known benefits of calorie restriction diets. These diets can make animals live longer; it’s thought that the body may respond to the lack of food by taking protective measures. Preliminary human tests suggest the drugs can boost older people’s immune systems and stop them from catching infectious bugs.

      Other researchers are looking at why organs start to pack up as their cells age, a process called senescence. Among the leading candidates for targeting and removing these decrepit cells from otherwise healthy tissues is a class of compounds called senolytics. These encourage the aged cells to selectively self-destruct so the immune system can clean them out. Studies have found that older mice on these drugs age more slowly. In humans, senescent cells are blamed for diseases ranging from atherosclerosis and cataracts to Parkinson’s and osteoarthritis. Small human trials of senolytics are under way, although they aren't officially aimed at aging itself, but on the recognized illnesses of osteoarthritis and a lung disease called idiopathic pulmonary fibrosis.

      Research on these drugs has highlighted a key question about aging: Is there a common mechanism by which different tissues change and decline? If so, could we find drugs to target that mechanism instead of playing what Harvard’s David Sinclair rails “whack-a-mole” medicine, treating individual diseases as they emerge? He believes there is, and that he has found a stunning new way to rewind the aging clock.

      In unpublished work described in his coming book Lifespan, he says the key to his lab’s work in this area is epigenetics. This fast-moving field focuses on how changes to the way genes are expressed, rather than mutations to the DNA itself, can produce physiological changes such as disease. Some of the body’s own epigenetic mechanisms work to protect its cells, repairing damage to DNA…

      Because aging isn’t officially a disease, most research on these drugs exists in a gray area: they don’t—or can’t—officially tackle aging….

Getting Ready for the Next Flood

[These excerpts are from an article by Shanti Menon in the Winter 2020 issue of EDF’s Solutions.]

      Climate change is making storms more frequent and mow damaging. Few places have made dlat fact more painfully obvious in recent years than North Carolina, where Hurricanes Matthew and Florence walloped the state with two “500-year” floods in 2016 and 2018. Florence took 43 lives and caused $17 billion in damage. One month later, tropical storm Michael hit. Then in September 2019, Hurricane Dorian pummeled the coast….

      In a state where the previous governor once said climate change was “in God’s hands,” the dialogue on climate change is changing….

      …In 2008, widespread flooding caused $10 billion of damage in Iowa, submerging nearly 3 million acres of farmland and inundating towns. Ten square miles of Cedar Rapids, Iowa, lay underwater, displacing 18,000 people. In response, Iowa invested in a comprehensive effort to reduce future flood damage….

      More than 10,000 acres of private land in the Middle Cedar River watershed are now using practices like buffers, ponds and keeping the soil covered with crops year-round to reduce flood risk and protect soil and water quality. Research from the Iowa Flood Center at the University of Iowa shows that these strategies, if used on a large scale, could have reduced Cedar Rapids flooding in 2008 by 7 inches — the difference between water at the doorstep and water inside homes. IFC experts are testing this approach in eight watersheds across the state and are planning a reciprocal visit to North Carolina.

      In the In years since its inception in the wake of the floods, IFC has built a network of 300 stream sensors, rain gauges and hydrologic stations, created floodplain maps for all 99 Iowa counties and developed sophisticated computer flood modeling systems, all of which allow it to make. real-time, publicly accessible flood forecasts for more than 1,000 communities. In 2016, IFC predictions helped Cedar Rapids prepare for its second biggest flood in histmr, greatly reducing flood damage….

The Rise of Clean Cars

[These excerpts are from an article by Charlie Miller in the Winter 2020 issue of EDF’s Solutions.]

      At the height of the Second World War, in July 1943, a chocking mist descended on Los Angeles. Residents reported that their eyes and throats stung and families piled into their cars and headed for the mountains. A rumor spread that the Japanese had launched a chemical attack.

      In fact, it was Los Angeles’ first brush with smog, a problem that would only grow worse in the coming decades. But if you compare a photo of Los Angeles in 1970 to one taken yesterday, you’ll see a big difference. The modern picture shows much cleaner air.

      This success is due to the 1970 Clean Air Act, which started the country along a path toward healthier air. Automakers were required to build cleaner cars, and they did, although not without a fight.…Today’s vehicles produce 99% less conventional pollution than those of 60 years ago.

      But the reduction in climate pollution was far less. The emergence of climate change as a critical issue, and the ongoing threat of air pollution to public health, demand that cars become even cleaner. So, in 2012, former President Obama finalized stringent new clean air standards. The standards, which would nearly double our current fuel economy by 2025, were adopted with broad support from automakers, labor and consumers. In poll after poll, Americans still support the initiative. Over the life of the program, cleaner cars will save consumers $1.7 trillion, save lives and lower climate pollution.

      The technology automakers need to make cars cleaner is ready, such as cylinder deactivation. Car companies are investing heavily in electric vehicles, and General Motors is spending $2 billion on a battery factory in Ohio.

      The Trump administration has put all this progress at risk. Deploying misleading and false analysis, the administration is poised to unveil its proposal to roll back the clean car standards….

      The administration has now taken the fight to the next level, moving to quash California’s long-established authority to set its own, stricter clean car standards. Under the Clean Air Act, California has the right to set its ownstandards and has often done so. Other states have the option of following California’s lead, and 24 states have, most recently Colorado….

      Remarkably, Ford, Honda, BMW and Volkwagen have all announced that they will adhere to California’s stronger standards. (GM, Chrysler and Toyota have sided with the administration.)

      …Clean cars save consumers money, cut climate pollution and protect human health. Even many car companies oppose the rollback. So who supports it, besides Chrysler, GM and Toyota? Just the Trump administration and some oil companies, which stand to sell more gasoline. They are on the losing side of history.

In the Heartland, Clean Energy Shines

[These excerpts are from an article by Shanti Menon in the Winter 2020 issue of EDF’s Solutions.]

      …Illinois added 1,300 solar jobs in 2018, a 37% surge driven largely by the state’s r landmark Future Energy Jobs Act….Now the state is set to expand on that law with the most comprehensive package of climate legislation in the country. The Clean Energy Jobs Act will increase renewable energy, boost electric vehicles and ensure that all communities benefit from the transition to a cleaner economy….

      Trump’s rollbacks have not impeded climate momentum across the country. States like Colorado and Pennsylvania and major utilities like Xcel Energy are also taking climate action that is helping set the stage for federal climate legislation….introduce a climate bill that will transition the country to a 100% clean economy — one that produces no more pollution than we can remove — by 2050. It’s an ambitious plan, but it’s in line with what scientists say the world needs to do in order to avoid the worst impacts of climate change. More than 150 lawmakers have co-sponsored the 100% Clean Economy Act….

      Colorado made history in May 2019 when it passed a law mandating a 90% cut in climate pollution across its economy by 2050 and at least 50% by 2030….

      Duke Energy, one of America’s largest utilities, with 7.7 million customers in the South and the Midwest, as well as Michigan’s DTE Energy plan to cut their carbon pollution 50% by 2030 and reach net-zero by 2050. These three utility commitments will create a yearly climate benefit by 2050 equivalent to closing 45 coal-fired power plants….

      …And New Mexico, which overlies part of the Permian Basin, the world’s top oil-producing region, has committed to at least a 45% reduction in climate pollution by 2030….

      Progress in places like these makes it clear that climate leadership is not limited by geography or long-standing links to fossil fuels. States, businesses and communities across the country are seeing the benefits of a clean economy that cuts pollution and creates prosperity….

      Illinois’ Clean Energy Jobs Act will grow the state's renewable electricity supply to 46% by 2030 and 100% by 2050. (The current target is 25% by 2025.) It will improve energy efficiency in buildings and offer incentives for electric buses and charging stations for cars and trucks. It will remove a subsidy that keeps dirty coal power plants — often in low-income neighborhoods — online. Other provisions will help protect displaced fossil fuel workers and expand clean energy job training.

      Instead of being rewarded for selling more energy, utilities will get paid for improving efficiency and reducing consumer demand during peak hours. This lays the groundwork for a clean, flexible grid that can accommodate a rise in electric vehicle charging and even the use of EVs as batteries to store clean energy….

Electric Trucks Pick up Speed

[These excerpts are from an article by Tasha Kosviner in the Winter 2020 issue of EDF’s Solutions.]

      Every day, more than 15,000 trucks pound through the neighborhood of Hunts Point in the Bronx, many bound for NewYork’s produce markets, spewing pollution as they go. It’s no coincidence that this area of New York City has some of the worst air quality and highest levels of childhood asthma in the city….

      Amid the diesel-belching behemoths clogging the road, their truck remains a novelty. EDF intends to change that. Alongside our work to shape the next federal diesel engine standards, we are working with businesses, utilities and governments to power up a rapid expansion in electric vehicles. Through our Truck and Bus Initiative, we envision the electrification of one-third of all new trucks and buses in the United States, China and Europe in the next 10 years. By 2040, that figure, for U.S. vehicles, must rise to 100%.

      The transition couldn’t be more urgent. Of the 385,000 premature deaths associated with global tailpipe pollution in 2015, diesel vehicles accounted for nearly half -- by far the largest contributor. Globally, emissions from trucks and buses are expected to double in the next 30 years. Yet to stay below the critical two degree global warming threshold established by the Intergovernmental Panel on Climate Change, the vast majority of global fleets must be zero-emission by 2050.

      …Electric trucks currently comprise less than 0.5% of the global vehicle fleet. To transform the industry, EDF needs to overcome the skepticism of fleet owners accustomed to diesel engines. We must drive down the cost of purchase — currently up to triple that of diesels — galvanize business demand and bolster manufacturer confidence. We must promote green electricity, work with utilities to manage increased power needs and engage policymakers at the city, state and federal levels. And all this must be done while ensuring that communities that suffer most from traffic pollution…also reap the benefits….

      To jump-start the initiative, EDF will launch pilot projects in Houston, Los Angeles and New York. In each city, we will partner with commercial and municipal fleet operators, utilities, regulators and others to establish prototype electric fleets. These fleets, and the network of private entities and public policies that support them, will serve as blueprints for a second phase of projects in more cities. Similar work will follow in London and China. Together, China, the United States and Europe comprise 65% of the global truck and bus market….

      A major barrier for early adopters is cost. Battery prices dropped 87% between 2010 and 2019 and they continue to fall. But at point of purchase, electric trucks and buses are unlikely to reach price parity with internal combustion engines for many years to come. Yet EDF modeling has shown that lower fuel costs and reduced maintenance mean that over the course of their lifetime, electric buses and some trucks are, in many circumstances, already cheaper than diesel. At an electric vehicle expo in New York City’s Union Square last fall, a salesman demonstrated why. Popping the hood of a truck, he pointed out the low number of moving parts. He showed how braking recharges the battery, reducing wear on the brakes. With typical New York swagger, he proclaimed he didn’t know how long it would take the brakes to wear out: It has never happened.

      In North Carolina, EDF is now using this fact to develop a plan to finance electric transit and school buses. Under this plan, utilities would fund the additional upfront cost of the vehicles and the school district or municipality would pay back the difference through its utility bills. Repayments would be set to never exceed the savings made….

      In a further innovation, the plan would see the utility retaining ownership of the batteries and charging infrastructure. When the buses are not in use, the utility could use the batteries to either feed back into the grid or — in a plan that will interest other storm-battered states as power sources during outages….

      Having more electric vehicles requires a greater supply of electricity. Even if companies and transit agencies want to commit to electrification, they are limited by what their utility can provide….

      With just 36 buses, power demand at the Port Authority of New York and New Jersey is relatively low. Larger fleets, or those that require high-speed charging, will need their utilities to provide the extra power. That can require major infrastructure works, which can take years.

      There are solutions at hand.

      In California, EDF worked with the Public Utilities Commission to develop cheaper off-peak charging rates that reduce stress on the grid and the need for additional infrastructure. We also advised on rules for operating big charging systems. The work is already having an impact. Among the state’s largest utilities, Southern California Edison is running a pilot to install hundreds of millions of dollars’ worth of charging infrastructure. And PG&E recently launched the nation’s first rate specifically for charging commercial electric vehicles….

      But what of the emissions from generating that power? The good news is that U.S. electricity generation is getting cleaner every year. And looking at how electricity is generated today, electric buses are already cleaner than diesel in every state.

      More must be done to grow renewable energy but vehicle electrification cannot wait. Companies typically upgrade vehicles every 10 to 12 years, so each new die-sel sel vehicle locks in emissions for a decade at least….

      For anyone living near busy roads, electric engines are far healthier….residents living near roads with heavy truck traffic had eight times higher exposure to air pollution than those living just a few blocks away and suffered higher rates of asthma, stroke and heart disease….

      There are clear signs that the transition to electric trucks is already underway. In 2019, 43 states took actions relating to vehivle electrification. California, Colorado, New York and North Carolina all have electrification plans tied to their climate goals. In Michigan, Nevada and Virginia, students will soon join peers in new York and California by going to school on electric buses….

Assessment in the Science Classroom

[These excerpts are from an editorial by Ann Haley MacKenzie in the February 2020 issue of The Science Teacher.]

      The word assessment conjures up so many questions for science teachers. Is it a necessary evil? When is it helpful and beneficial? What is lost during the mandatory weeks of proctoring standardized exams to our overtested, stressed, and, sometimes, apathetic students?

      …a test brought about by lawmakers who have never taught, but who believe it is their duty to often wreak havoc on teacher and students’ lives.

      There are districts losing weeks of instructional time each year while their students take a plethora of standardized tests. These weeks do not include all the time some teachers spend preparing their students for these exams. I believe time is better spent doing science rather than testing the curiosity and wonder out of our students.

      …What if you have a high school student functioning at the elementary level? What if you have students for whom English is a second language? The tests are often inequitable in these situations, even when students are provided support.

      We as teachers seem to be silent when it comes to arguing what should be going on in our science classrooms. NSTA provides a solid platform for expressing the concerns of science teachers in front of politicians, the media, and other sources needing to hear from us.

      Authentic assessments, unlike standardized tests, have a vital role. They can demonstrate growth over time in the students. Utilizing authentic assessments that play to students’ strengths is an important area of consideration….

      One size of assessment does not fit all. Play to your students’ strengths….Give them the opportunity to decide just how they will demonstrate their knowledge. Adolescent learners need choices; their voices need to be part of the decision-making process for how they will be assessed. By providing them with various ways to demonstrate their understandings and conceptual knowledge, we can better determine the gaps and strengths in our teaching practices.

      After all, assessment means “the evaluation or estimation of the nature, quality, or ability of someone or something.” Do our assessments address the abilities of our students….

Hidden Figures

[These excerpts are from a book review by William P. O’Hare in the 7 February 2020 issue of Science.]

      …focuses on the extent to which many marginalized populations are often not counted in official statistics and the extent to which wealthy individuals and families are often able to hide their financial resources, properties, and holdings from the government to paying taxes on these assets.

      Cobham documents a range of situations where people are missed or undercounted in official statistics, from United Nations figures to country surveys. More often than not, the most frequently missed groups are those that are economically and socially marginalized. When such groups are not accounted for, it often leads to reduced political power as well as reduced economic well-being.

      Many marginalized groups have rela-tively high net undercount rates in the U.S. census…, and areas with high concentrations of these groups often do not receive their fair share of government aid….

      The political overtones of how power can be used to deliberately undercount marginalized groups was on full display in the buildup to the 2020 U.S. census. The Trump administration, acting through the U.S. Department of Commerce, tried to add a question to the 2020 U.S. census regarding citizenship status, knowing that it would depress participation of populations with large numbers of immigrants. This attempt—which was eventually struck down by the U.S. Supreme Court but was then the subject of an executive order with similar goals—was made despite the objections of the experts at the Census Bureau, all living former Census Bureau directors, and many other statistical experts.

      Cobham next turns his attention to uncounted money and the extent to which people can hide their resources from the authorities. Hidden resources not only deprive countries of their fair share of tax revenue, they mask the real extent of economic inequality.

      Here, Cobham documents efforts currently under way to make the financial world more transparent. While such efforts are still young, they appear to be having mixed success….

      Throughout the book, Cobham argues that a lack of good data on population and finances is a major hindrance to good governance. Without good data…we have little idea if a policy or program is having a positive or negative impact.

      …Cobham makes the case for several changes in law and regulations that could help us get a more accurate assessment of populations and resources that currently go uncounted….

The Road to a 100% Clean Economy

[These excerpts are from an editorial by Fred Krupp in the Winter 2020 issue of EDF’s Solutions.]

      As we enter a new decade, the reality of cli-mate change is hitting home….

      Limiting climate change is a daunting task. Global emissions are still on the rise, but I'm encouraged by some recent developments. Young people around the world, who have the greatest stake in the future, are bringing new energy and passion to the cause. They understand the urgent need for action. In the U.S., cities and states are stepping up as never before to do their part.

      In Washington, D.C., too, legislators are beginning to wake up. In late November, the 100% Clean Economy Act was introduced in the House with the support of more than 150 co-sponsors….It’s a bold plan to slash climate pollution to net zero by 2050 at the latest, which is the ambitious but achievable climate goal we need.

      We’ve made good progress in the U.S. electric power sector: emissions are down over the past decade as coal-burning power plants close. But we can't get to an economy that’s 100% clean without going further on electricity and addressing every source of climate pollution, including transportation, now the country's number one source (see cover story….

      We’re off to a good start. In 2018, the global electric car market was 5.1 million, up 2 million from 2017. And EDF is working with citizens, utilities and governments to rapidly expand deployment of electric trucks and buses. This is critical because trucks are among the fastest-growing pollution sources globally.

      Airplanes and ships will also be getting cleaner. The International Civil Aviation Organization has agreed to cap carbon emissions from international flights beginning in 2021, with more than 80 nations participating….

      But we’re facing strong headwinds from the Trump administration, in the form of furious efforts to roll back popular clean car standards for automobiles….

Cryptic Predators

[Theis excerpt is from an article by Sandrine Ceurstemont in the February 2020 issue of Scientific American.]

      When ecologist Jose Valdez and his team released 10,000 tadpoles to populate a new conservation site in Newcastle, Australia, they surrounded the area with a mesh fence to keep out hungry snakes, birds and mammals. But they hadn’t considered much smaller predators: diving beetles. The researchers soon began to witness the insects’ violent attacks, and three years later only a handful of frogs remained….

      Predators are usually larger than their prey, with vertebrates such as amphibians typically doing the eating when it comes to insects. Although role reversal has been reported—such as praying mantises consuming lizards—scientists consider this rare. Valdez suspects insects' predatory behavior has been underestimated, however….

      It is unusual to see insects hunting in packs. But while monitoring one pond at night, Valdez saw about 12 adult diving beetles surround a tadpole and quickly pull it apart….

      The researchers also noticed that certain diving beetles laid their eggs inside frog egg clutches, seemingly timed to hatch so the insect larvae could hunt down newborn tadpoles. The beetle larvae killed up to three tadpoles an hour, often discarding a half-eaten one if another was close by. “None of these behaviors were documented before,” Valdez says….

      Because insects are small, their predatory behavior is easy to miss—and they often attack in difficult-to-observe settings, such as at night or underwater. But such assaults are emerging from the shadows: recent studies have documented praying mantises regularly eating small birds, as well as giant water bugs consuming vertebrates such as turtles, frogs and snakes in Japanese rice fields.

      Insect predation could play a hidden role in declining amphibian populations. The International Union for Conservation of Nature estimates that at least 40 percent of amphibian species are threatened with extinction….

      Next, Valdez plans to quantify diving beetle predation on various amphibians. He will analyze insect gut contents and use cameras to capture more of the behavior….

Profits, Prejudice, and Plant Patents

[These excerpts are from a book review by Helen Anne Curry in the 31 January 2020 issue of Science.]

      …In 2016, the conviction of a Florida physicist on charges of conspiring to steal trade secrets confirmed that seed theft had also become, at least to those who influence U.S. federal policies and procedures, a national security threat….

      The U.S. Federal Bureau of Investigation (FBI) spared little expense in developing a case against Mo. A 2-year period saw 73 agents devote time to the effort, 17,000 emails intercepted, hundreds of hours of audio recorded and transcribed, and more. All of this was done to defend the intellectual property of two extremely profitable, world-leading agribusinesses —"American industry”—against the haphazardly organized incursions of an expanding Beijing-based animal feed corporation that did not even have the expertise in place to efficiently exploit stolen seeds—"unfair foreign competition.”

      To understand why the U.S. government devotes a substantial amount of taxpayer dollars to investigating and litigating on behalf of Monsanto…one really needs to appreciate global politics.

      Hvistendahl considers factors that range from the FBI's post-Cold War refashioning, which contributed to a new narrative of industrial espionage as a national security threat, to the effects that greater meat consumption in China have had on demand for feed corn and, therefore, seed corn. The consolidation of agribusiness features prominently as well, a factor that both explains, and is explained by, the dogged defense of patents on corn and other crop varieties described above.

      …For nearly two decades, the FBI and other U.S. agencies have expounded an account of China's espionage strategy in which the Chinese government is said to rely on “a dispersed network of nontraditional collectors” rather than professional agents. This vision of a “'human wave' of students, scientists, and engineers...who gather intelligence ad hoc” wrongly implicates all ethnic Chinese working in the United States as potential spies for the Communist Party.

      Hvistendahl provides evidence that this characterization, which evokes old racist fears of “the yellow peril,” not only is fundamentally inaccurate with respect to China’s state-led spy operations but also produces racially motivated suspicion, hostility, and harm. Wrongful investigations have ruined careers and lives.

      Is American industry really at risk? Or is it values such as tolerance, openness, and justice that are truly in danger?...

Game Over

[These excerpts are from a book review by Stacie L. Pettyjohn in the 31 January 2020 issue of Science.]

      …an overview of German Admiral Karl Doenitz’s plan to use a fleet of U-boats to cut off commerce to the United Kingdom, which the island nation needed to stay in the war. Although a similar strategy had been tried unsuccessfully in World War I, Doenitz believed that improved communications would enable groups of U-boats to operate together, like a wolf pack, and allow them nate and defeat escorted convoys.

      Doenitz’s plan, devised in 1937, was not realized until June 1940, when Germany’s occupation of France gave it Atlantic bases. Nazis called this the “happy time” because their U-boats roamed the seas with impunity, sinking civilian vessels carrying cargo….According to Parkin, this success was largely due to bold tactics developed by German Captain Otto Kretschmer, who launched night attacks within the columns of a convoy, firing torpedoes at point-blank range, then submerging until the convoy dispersed.

      In January 1942, Winston Churchill enlisted Captain Gilbert Roberts to lead a small organization—the Western Approaches Tactical Unit (WATU)—charged with identifying U-boat tactics, developing effective countermeasures, and teaching British sailors to use new countermaneuvers. Lacking competent men to staff WATU, Roberts turned to the Women’s Royal Naval Service (known as the “Wrens”), which assigned women who had a “keen mind for numbers” to build and run a game modeling a two-sided tactical fight between British escorts and German U-boats.

      During this game, the two sides maneuvered their respective vessels, dropped depth charges, and fired torpedoes on a linoleum floor, where each 10-inch square represented one nautical mile. The British team commanded their escorts from behind white sheets designed to limit their line of sight to replicate the view from a ship's bridge. While British ships were outlined in conspicuous white chalk, the U-boats were marked in green, rendering them invisible. Throughout the game, the Wrens measured and marked the ships' movements, provided intelligence, guided discussions, and played as the German team. Roberts presided over the game and the postgame discussion.

      Parkin nicely highlights how this war game was used for multiple purposes at different times during the war. Roberts and the Wrens first used the game to uncover Kretschmer’s tactical innovation, for example. They then used it to develop and test countermeasures. Additionally, the game was used to teach skeptical audiences the superiority of WATU’s countermeasures when compared with existing tactics. By the war’s end, nearly 5000 sailors had taken WATU’s weeklong course covering four different battle scenarios.

      …when British convoys used WATU-developed tactics and, bolstered by aircraft and naval support groups, fended off the largest wolf-pack attacks of World War II. After 41 U-boats were sunk in May 1943, the Battle of the Atlantic turned decisively toward the Allies….

      Sadly, the Wrens were an anomaly, reflecting a brief moment when women were war games out of necessity, operating in a field that to this day is dominated by men. Yet gender diversity has been shown to yield better and more innovative solutions in such settings, and achieving it should be a priority.

A Microbiome Silver Bullet for Honey Bees

[These excerpts are from an article by Robert J. Paxton in the 31 January 2020 issue of Science.]

      The western honey bee (Apis mellifera) brings tangible benefits to humans as an important pollinator and insights into social evolution as a model organism. Yet, despite close scientific scrutiny, it is under global threat from a range of stressors…that are unlikely to diminish with global change. Chief among these are pests and pathogens, remedies to which are either ineffective, short-term, expensive, or impractical….Leonard…reveal a hidden microbiological key to fight these pests and pathogens: genetically modified honey bee gut bacteria tailored to induce host RNA interference (RNA1)-based defense…that is effective, long-term, potentially cheap, and easy to apply. This important approach may not only provide a solution to many of the honey bee's woes, it also offers a new functional genomic toolkit with which to dissect the molecular intricacies of honey bees and their societies.

      Originally brought to the Americas by early European settlers, the honey bee is now globally distributed and indispensable in agriculture. Yet its success—and intercontinental transport—has been accompanied by the spread of its numerous pests and pathogens, foremost among which are the exotic Varroa destructor (hereafter “varroa”) ectoparasitic mite and deformed wing virus (DWV), a killer pathogen transmitted by varroa mites….The varroa-DWV nexus is widely blamed for increased honey bee mortality across the temperate world and both mite and virus are nowadays ubiquitous, infecting more or less every hive…; colony collapse is the outcome. Current treatments include a range of natural and synthetic miticides to kill varroa or high-tech solutions that induce a natural innate host defense mechanism, RNAi, to reduce pathogen (including viral) burden….But the former has limited efficacy because mites soon evolve resistance; moreover, miticides can enter the human food chain through contamination of honey. The latter, by contrast, has proven effective in controlling DWV…but is expensive and the benefits are temporary—on the order of days or weeks. Now, Leonard…have genetically modified one honey bee gut bacterium, Snodgrassella alvi, thereby refining a system to induce RNAi within hosts. This approach seems to offer bees sustainable protection from varroa or DWV. Could this be a silver bullet for the honey bee?

      RNAi is a biological process found in most eukaryotes that regulates endogenous as well as exogenous (foreign) RNA, such as that of viruses. Introducing exogenous double-stranded RNA (dsRNA) into a host cell causes that cell's molecular machinery to degrade like-sequenced RNA. This can reduce the expression of a corresponding host gene (so-called gene “knockdown”) or lead to the destruction of a viral RNA, resulting in viral control….But there is a catch—dsRNA is expensive to produce in large quantities, inherently unstable, and difficult to direct into host cells, where it is needed.

      …an insect’s gut bacteria—its microbiome—can be engineered to express copious dsRNA in a stable manner that acts systemically in insect hosts. Leonard…have perfected this approach by engineering S. alvi to express varroa or viral genes and feeding the engineered bacteria to honey bees. When the corresponding varroa or viral dsRNA was produced by the ingested bacteria (and then taken up by the host—in the case of varroa, even passed on to mites feeding on honey bee tissue), the host's RNAi machinery was activated to destroy those RNA sequences—self-destruction in the case of varroa. Thus, when treated honey bees were subsequently challenged with varroa or DWV, mites died and viral replication was suppressed: a major breakthrough in their control….

      …laboratory-based experiments used handfuls of worker honey bees. The next step is to scale up with full-sized colonies, which contain up to 50,000 individuals, to demonstrate field-realistic feasibility….

      Other major problems facing honey bees include insecticide (mis)use and loss of flower-rich habitat….Honey bee gut bacteria engineered to alter host expression of genes involved in detoxification or pollen digestion might go some way to resolving these problems, too. As well as promising insights into fundamental aspects of biology….approach has great potential to improve bee—and even our own—health….

Beating Back Extinction

[These excerpts are from an article by Jason G. Goldman in the Febuary 2020 issue of Scientific American.]

      Scientists, conservation organizations and governments trying to stem the tide of extinction often focus efforts on protected areas such as national parks and wildlife preserves. But with as many as a million species at risk, this strategy may not be enough to conserve wildlife, especially in a world increasingly disrupted by climate change.

      Slowing the mass extinction that now appears to be underway will require more creative means of coexisting alongside wild plants and animals. A new study underscores the effectiveness of some such approaches by examining indigenous-managed lands….

      Schuster and his team analyzed more than 15,000 areas in Australia, Brazil and Canada. They found that the total diversity of birds, mammals, amphibians and reptiles was highest on lands either managed or comanaged by indigenous groups, whereas randomly selected locations with no formal protection were the least biodiverse. For threatened species in particular, indigenous lands scored slightly higher than protected lands on overall species richness in Brazil and Canada, as well as higher for threatened amphibians and reptiles in Australia, mammals in Brazil, and birds and reptiles in Canada….

      Each country has a different geography, climate and colonization history. Yet remarkably, Schuster says, the best indicator for species diversity is whether a given area was managed by an indigenous community. He points out that practices such as sustainable hunting, fishing and foraging, as well as pre-cribed burning, are more likely to occur in such areas….

Weight Is Not Enough

[These excerpts are from an editorial by the editors in the Febuary 2020 issue of Scientific American.]

      …Higher body masses are associated with increased risk for hypertension, diabetes and coronary disease. Many epidemiological studies of hundreds of thousands (in some cases, millions) of patients have shown that heavier people are at higher risk for these illnesses. But the big picture is not the whole picture. Researchers have identified a subset of obese people considered to be “metabolically healthy”—meaning they do not exhibit elevated blood pressure or the diabetes precursor called insulin resistance, for example. Although the numbers vary greatly depend-ing on the study, the metabolically healthy population could comprise anywhere from 6 to 75 percent of obese individuals.

      One intriguing report published in 2016 found that a higher body mass index (or BMI, the ratio of weight to height) “only moderately increased the risks for diabetes among healthy subjects” and that unhealthy thin people were twice as likely to get diabetes as healthy fat people. Clearly, there is more to the equation than weight. Although the association between excess weight and disease is very real, individual experience can vary greatly and hinges on personal physiology and behavior.

      Despite such findings, doctors routinely recommend dieting for weight loss as a means to “treat” poor health indicators such as high cholesterol and insomnia in obese patients—an approach with an abysmal success rate. Virtually no diet works in the long term….Spending years trapped in a cycle of losing weight, regaining it, then losing it again is associated with poorer cardiovascular health outcomes and contributes to hypertension, insulin resistance and high cholesterol. It is time that doctors ditch the scale-centric health care practice and focus on behaviors that have proven positive outcomes for health. Lifestyle changes, such as enhancing on’'s nutrition by eating fruits, vegetables and whole grains, along with increased physical activity and smoking cessation, can improve blood pressure, blood lipid levels and insulin sensitivity—often independently of changes in body weight.

      Among the more insidious by-products of weight-centric health care are the increased stigma and shame experienced by the overweight. The well-reported anecdotal experience of innumerable fat people is that doctors often prescribe weight loss without examining them, running tests or performing other normal procedures for conditions that thin people would be screened for automatically….

      …And research suggests that the chronic stress of living with the shame of being a heavy person may underlie metabolic changes that increase the storage of fat, elevate blood pressure and drive up blood lipid levels….

The EPA Hits a New Low

[These excerpts are from an article by Andrew Rosenberg in the Febuary 2020 issue of Scientific American.]

      The U.S. Environmental Protection Agency has one job: to protect public health and safety and the environment we live in, with the best available science. It is a mission that saves lives. But that mission could end if EPA administrator Andrew Wheeler succeeds in restricting the science that the agency can use.

      …It sounds like a small change, but it has the potential to do enormous damage.

      An attempt to add this rule in 2018 was met with widespread condemnation from public health experts and the science community. A supplemental proposal is a new effort by Wheeler to abandon science-based protections that have worked effectively for decades to deliver cleaner air, cleaner water and healthier communities. So what does the rule do in its “clarified” form?...

      It is a political change made to achieve political goals. Far from a move toward transparency, this rule was designed by political staff on the basis of proposals long pushed by lobbyists for the tobacco industry and fossil-fuel extractors. The EPA's own scientific experts were secondary to the process, and its Science Advisory Board was given very little opportunity to review it. Worse, the EPA administrator can pick and choose when the rule does and does not apply—the exact opposite of a transparent or science-based process. The EPA got nearly 600,000 critical comments on the original proposal, including opposition from major scientific societies, public health groups and universities. It largely ignored them.

      This proposal puts a set of handcuffs on the agency, with industry-linked political appointees holding the key. It will make it harder for the EPA to protect communities or to hold polluters accountable. It is a declaration by Wheeler and his deputies that they don't care about public health.

The Pollinators: A Different Kind of Bee Movie

[These excerpts are from a movie review by Jacob Clark Blickenstaff in the Febuary 2020 issue of NSTA Reports.]

      …Bees have been getting attention for the last 10-15 years because of significant die-off events that threaten commercial agriculture worldwide. The 2019 documentary The Pollinators gives a detailed picture of the commercial bee industry in the United States, and examines the ongoing threats to bees….The documentary includes suggestions for how individuals can make choices in their daily lives to support both managed and native pollinators.

      Many of the fruits and vegetables we expect to regularly find in the supermarket rely on insects for pollination. Recall that pollen from a male flower has to get to a female flower to produce a fruit, and that what a botanist defines as a “fruit” includes a lot of produce a dietician would call a “vegetable,” including peppers and tomatoes. Bees are so important for the pollination of nut trees like almonds that millions upon millions of bees are trucked to California every year for the short pollination season. Once that season ends, the bees are packed up and moved to other parts of the country to pollinate other crops like apples, cherries, and blueberries. Some beekeepers move their hives more than 20 times each year, following the flowering /pollinating schedules of different crops.

      Many separate threats to bees have combined in recent years to make it especially hard for both managed and native bees to survive. Farmers have switched to pesticides that are less harmful to people, which is good. Unfortunately, the newer pesticides take longer to degrade in the environment, so once the pesticide is on a field, it can be toxic to bees for years to come. Other chemicals used on farms are also harmful, including fungicides to control fungus on crops and herbicides to control weeds.

      When one kind of crop takes over large areas of land, only a short window of time occurs when that crop produces the nectar and pollen that bees need for food. Managed bees are fed or moved on to another crop, but local native bees have nothing to eat when the crop is not blooming. With little or no food, the hive is severely weakened.

      Bee colonies can also become infested with an even smaller insect, the verroa mite, a bee parasite. It attaches to the body of a young pupa or adult bee and sucks out essential nutrients. If several mites attach to one bee, they might kill it outright. The mites also carry viruses harmful to bees, causing even greater damage.

      While a healthy colony could probably handle any one of these three threats, two or more could be fatal. A feedback loop exists in which the one problem weakens the colony, making it more susceptible to additional threats.

      …Native bees and other pollinators can’t move away from pesticides or from areas where crops replace seasonal forage, so they are even more susceptible to these hazards….

      No field can be used repeatedly without periodic “rest.” Some farmers are planting a bee-friendly cover crop that flowers during much of the year. That way, local bees can find food outside of the bloom time for the farmer's main crop.

      Another method to limit pesticide use is to try to concentrate the pest insects in one place. Some plants are especially attractive to the pest bugs, so a narrow strip of those “bait” plants can collect a lot of the pests, and the pesticide can be applied in that small area, rather than over the whole field. (This strategy is also much less expensive for the farmer, another big plus.)

      We as individual consumers can take several other measures that can support bees and other pollinators:

      • Plant a pollinator garden to provide forage for most of the year….

      • Avoid using pesticides unless absolutely necessary….

      • Buy local honey to support local beekeepers.

      • Consider purchasing fruits and vegetables that are less than “perfect” so that farmers will have a market for crops that use fewer chemicals in their production….

United Kingdom Breaks from EU Farm Subsidies

[These excerpts are from an article by Erik Stokstad in the 24 January 2020 issue of Science.]

      …the U.K. government proposed radical changes to £3 billion a year in agricultural spending that will focus the money on benefits to climate, ecosystems, and the public. “It’s dramatic and utterly critical,” says Dieter Helm, an economist at the University of Oxford. “This is an agricultural revolution.”

      …farmers will be given subsidies not simply for cultivating land—the current EU system—but only for delivering “public goods.” These include sequestering carbon in trees or soil, enhancing habitat with pollinator-friendly flowers, and improving public access to the countryside. To ease the transition, direct subsidies will be phased out over 7 years beginning in 2021, and new payments for environmental services will be tested in pilot projects….

      After the destruction and starvation of World War II, European tariffs helped protect farmers from foreign competition while subsidies boosted their yields….New lands were brought under the plow and hedgerows were ripped up, leading to erosion. Excessive fertilizer and pesticides polluted air and water. And the loss of habitat harmed pollinators and ther wildlife….

      …The new bill addresses only England, because the United Kingdom allows Wales, Scotland, and Northern Ireland to determine their own agriculture policies….

      …But Helm sees lifelines for some of these farms, such as payments for sequestering carbon with tree plantations or restored peatlands. Grants for restoring heritage buildings or enhancing landscape beauty could also help sustain farms while boosting tourism. Other payments will help farmers adapt to climate change or reduce their environmental impact. Subsidies for equipment to inject manure into the soil, for example, could reduce both air pollution and the need for chemical fertilizers.

      About one-eighth of existing U.K. farm subsidies pay for environmentally friendly activities such as maintaining hedgerows and other habitat, and those efforts will expand….

      …figuring out how to maximize the benefits will require research. Carbon sequestration payments could backfire if used in the wrong places. For example, planting trees in peatlands can dry them out, releasing more greenhouse gases than would ever be sequestered by the trees….

      Other countries will be watching closely….

Overhaul Environmental Risk Assessment for Pesticides

[These excerpts are from an article by C.J. Topping, A. Aldrich and P. Berny in the 24 January 2020 issue of Science.]

      Among aspects of agricultural intensification that have been criticized for negative impacts on biodiversity…, pesticides have been linked to declines in insects, birds, and biodiversity in aquatic systems….If pesticide use is to blame, even partially, then this raises questions both about pesticide use and the regulatory procedures that are used to protect the environment….Environmental risk assessment (ERA) of pesticides does not account for many stressors that have intensified in recent years, such as climate change, habitat destruction, and increasing landscape homogeneity, the combination of which can aggravate effects of pesticides in nature….

      The aim of ERA is to determine whether use of a pesticide can be made safe for a receiving environment. The current regulatory procedure evaluates each product separately for each agronomic use—a single-product, single-crop assessment, resulting in authorization or nonauthorization of the product for that use. This approach makes the regulatory scheme tractable, and if the risk is managed appropriately and the product applied accordingly, then pesticides should not pose an unacceptable threat….

      Risk assessments are based on the use of a single pesticide in a specific crop. Yet, the number of mixtures and sequential treatments with pesticides in the landscape can be very high…and is the norm across Europe….Similar situations are described in the United. States, Australia, and elsewhere. Any organism spending time in a single field is unlikely to face a single-product scenario, necessitating the consideration of the application sequence in the ERA. The current approach also ignores scale of use; hence, once approved for a crop, the area over which that crop is grown is not considered.

      …Where direct exposure to nontarget organisms makes harm unavoidable (for example, insecticides applied to kill insect pests may kill nontarget insects), the ERA requires recovery experiments to demonstrate recovery potential. For most species, recovery in the contaminated area is by emigration from source habitats. However, this assumes a balanced source-sink dynamic that does not reflect intensive modern agriculture. The experiment, conducted for single fields or plots within an untreated area, does not represent the real ratio of source and sink habitat, something constantly changing because of continued agricultural intensification. The consequence is an underestimation of the risk in the long term…as source areas become depleted owing to dispersal of organisms into the sinks contaminated with pesticides.

      In addition, in a mosaic of pesticide applications, wide-ranging animals (such as honey bees) are exposed to a cocktail of pesticides even more diverse than that applied to a single field. Current ERA also does not consider temporal dynamics. A declining population will be less resilient to future stressors, and thus, a spiral of decline may ensue. ERA ensures that assumptions regarding population health will be incorrect because multiple (regulated and nonregulated) stressors are ig-nored entirely.

      …The sensitivity of a few surrogate species is assumed to reflect the sensitivity of all organisms. Often, the choice of surrogate species is based on which species can be reared in the laboratory….

      Policy goals for ERA are changing, yet ERA ractice does not reflect this….

      Overall, the risks must be communicated to the public, whose choices will ultimately determine the future of agricultural production and landscapes. Recent studies about the plight of biodiversity have already alerted the public, which is now putting pressure on industry, farmers, and regulators. The time is therefore right. This future view of pesticide ERA and regulation cannot address all concerns nor remove all uncertainties. However, we should not let the perfect be the enemy of good. We can retarget ERA to address better the key environmental questions. This will always be a compromise that needs to be balanced with input from all stakeholders. However, it is feasible, and the need for action is urgent.

Drop the Chalk

[These excerpts are from an editorial by H. Holden Thorp in the 24 January 2020 issue of Science.]

      …Despite evidence to the contrary, most science departments believe that the only way to produce scientists is to bludgeon young people with too much material, in the wrong setting, at the wrong time, and with the wrong kinds of assessments. The rationale is that only by mastering an abundance of facts and quantitative skills can someone become a scientist—and that’s where one must start, not finish.

      I understand the people who make this case because I used to be one of them, a professor filled with righteousness about all of the things that students had to learn. Then I went into administration, saw the data on how poorly universities were doing, and changed my mind. A smart social science colleague told me that instead of weeding out, we should be weeding in. That rocked my world. Even so, I mostly failed at getting the PowerPoint and the big chalk out of the hands of my colleagues who were convinced that the old way was the right way.

      …Lots of research on learning supports the idea that we learn new things best when we need them….

      …active learning that is heavy on group work and discussion creates a better opportunity for students of all identities to succeed in science. Yet 55% of all science instruction in the United States is still traditional lecturing. Only 27% has a modest intervention such as multiple-choice questions with clickers to engage students during class. And only 18% is designed for students to work through problems together in class after learning didactic material in advance. This is the face of modern science education, even when a Nobel laureate has shown that lectures don't work effectively.

      Whom do lectures work for? They work for those who love to memorize facts and equations and can “plug and chug” on exams. They work for those who are not subjected to social cues that make sitting in a large lecture hall and taking high-stakes tests intimidating. They work for those who look like the people who were in the classrooms when this method of teaching was invented. That’s not fair and it’s not going to cut it for the future of science and the planet….

Just Say No!

[These excerpts are from an article by Andrew Zucker, Pendred Noyce and Andrew McCullough in the January 2020 issue of The Science Teacher.]

      …As the use of social media increases-45% of teens say they are online “almost constantly…”—misinformation spreads faster and further. Even as schools continue to provide accurate information to young people, science teachers now also need to teach students how to judge the quality of supposedly “scientific” information they encounter online, on TV or radio, from friends, or anywhere.

      …reading the newspaper makes it obvious that scientific misinformation is a serious problem that requires teachers’ attention. Moreover, science—with its accepted methods for verifying new claims and building common knowledge—provides an ideal domain for honing the skills needed to be a critical consumer of information.

      Moreover, social science research shows it is possible to “inoculate” people against misinformation; in other words, teachers can use experimentally tested approaches that will help students learn to separate science fact from science fiction….

      There are several other reasons it has become important to teach students how to judge the accuracy of allegedly “scientific” claims. For one thing, research shows that some people, such as climate change skeptics, accept scientific misinformation not from a lack of knowledge but from cultural polarization….Furthermore, there are too many false “scientific” claims for teachers to focus separately on each of them. More than ever, then, students need to be taught how to think critically about dubious claims.

      In addition, studies confirm what many teachers already know: students typically are not good at searching for reliable information online. Many students are unaccustomed to questioning the first online resource they encounter, even if it is wholly unreliable….

Scientific Media Literacy

[These excerpts are from an editorial by Ann Haley MacKenzie in the January 2020 issue of The Science Teacher.]

      Fake news. Pseudoscience. Bad Science. Never before has so much information, both good and bad, been available to us. One study of students' online reasoning skills found that “96 percent of students did not consider why ties between a climate change website and the fossil fuel industry might lessen that website's credibility. Instead of investigating who was behind the site, students focused on superficial markers of credibility…."

      Another study…found that students could not discern fact from fiction when exposed to scientific posts on social media. For most of us, this finding is probably not surprising. But what are we doing to counteract this situation in our science teaching? Do we focus on media literacy in our classrooms? What activities do we do to make our students better consumers of science information?

      …If our students graduate knowing the steps of the Krebs cycle but cannot read and interpret scientific reports and social media posts, then we have failed. Our students are consumers of the plethora of information present in today’s world. They are future voters on vital issues, such as climate change, bioengineering, and other scientific phenomena. It is paramount that they understand the science behind these issues.

      In 2007 it was estimated that “70 per-cent of Americans can’t read and understand the science section of the New York Times.” Although this statistic is dated, my hunch is that the percentage is most likely about the same. Currently, 69 percent of U.S. adults say their trust in the news media has decreased in the past decade….With this mistrust in the media and with the huge amounts of new scientific information surfacing daily, it is imperative that we move media literacy near the top of what we do as science educators. Factoids come and go but scientific literacy is a lifelong skill we must help our students master.

Born in China, Taught by AI

[These excerpts are from an article by Karen Hao in the January/February 2020 issue of MIT Technology Review.]

      …Experts agree AI will be important in 21st-century education—but how? While academics have puzzled over best practices, China hasn’t waited around….

      But experts worry about the direction this rush to AI in education is taking. At best, they say, AI can help teachers foster their students' interests and strengths. At worst, it could further entrench a global trend toward standardized learning and testing, leaving the next generation ill prepared to adapt in a rapidly changing world of work.

      As one of the largest AI education companies in China, Squirrel highlights this tension. And as one of the best poised to spread overseas, it offers a window into how China’s experiments could shape the rest of the world….

      Every educational expert I spoke to for this story began by making the same point: to understand how AI could improve teaching and learning, you need to think about how it is reshaping the nature of work. As machines become better at rote tasks, humans will need to focus on the skills that remain unique to them: creativity, collaboration, communication, and problem-solving. They will also need to adapt quickly as more and more skills fall prey to automation. This means the 21st-century classroom should bring out the strengths and interests of each person, rather than impart a canonical set of knowledge more suited for the industrial age.

      AI, in theory, could make this easier. It could take over certain rote tasks in the classroom, freeing teachers up to pay more attention to each student….

No Computer Left Behind

[These excerpts are from an article by Natalie Wexler in the January/February 2020 issue of MIT Technology Review.]

      …Schools across the country have jumped on the education technology bandwagon in recent years….As older education reform strategies like school choice and attempts to improve teacher quality have failed to bear fruit, educators have pinned their hopes on the idea that instructional software and online tutorials and games can help narrow the massive test-score gap between students at the top and bottom of the socioeconomic scale. A recent Gallup report found that 89% of students in the United States (from third to 12th grade) say they use digital learning tools in school at least a few days a week.

      Gallup also found near-universal enthusiasm for technology on the part of educators. Among administrators and principals, 96% fully or somewhat support “the increased use of digital learning tools in their school,” with almost as much support (85%) coming from teach-ers. But it's not clear this fervor is based in evidence. When asked if “there is a lot of information available about the effectiveness” of the digital tools they used, only 18% of administrators said yes, along with about a quarter of teachers and principals. Another quarter of teachers said they had little or no information.

      In fact, the evidence is equivocal at best. Some studies have found positive effects, at least from moderate amounts of computer use, especially in math. But much of the data shows a negative impact at a range of grade levels….college students in the US who used laptops or digital devices in their classes did worse on exams. Eighth graders who took Algebra I online did much worse than those who took the course in person. And fourth graders who used tablets in all or almost all their classes had, on average, reading scores 14 points lower than those who never used them—a differential equivalent to an entire grade level. In some states, the gap was significantly larger….

      Judging from the evidence, the most vulnerable students can be harmed the most by a heavy dose of 'technology—or, at best, not helped….. A flipped college math class resulted in short-term gains for white students, male students, and those who were already strong in math. Others saw no benefit, with the result that performance gaps became wider.

      Even more troubling, there’s evidence that vulnerable students are spending more time on digital devices than their more privileged counterparts. High school students in questionable online “credit recovery” courses are disproportionately likely to be poor or members of minority groups (or both)….

      The dangers of relying on technology are also particularly pronounced in literacy education and at early L grade levels….

      Why are these devices so unhelpful for learning? Various explanations have been offered. When students read text from a screen, it's been shown, they absorb less information than when they read it on paper. Another frequently cited culprit is the distraction the devices afford….

      …while technology can do a credible job of imparting information, it’s not so good at demonstrating the “social usefulness” of knowledge….

      In addition to sapping motivation, technology can drain a classroom of the communal aspect of learning. The vision of some ed tech advocates is that each child should sit in front of a screen that delivers lessons tailored to individual ability levels and interests, often on subjects chosen by the students themselves. But a vital part of education is different kids bouncing their ideas off each other….

      Still, recognition seems to be growing that technology can be counterproductive….

      Educators and reformers aiming to advance educational equity also need to consider the mounting evidence of technology’s flaws. Much attention has been focused on the so-called digital divide—the relative lack of access that lower-income Americans have to technology and the internet….But let’s not create a digital divide of the opposite kind by outsourcing their education to devices that purport to build “skills” while their peers in richer neighborhoods enjoy the benefits of being taught by human beings.

It Gets Worse

[These excerpts are from an article by Malcolm Harris in the January/February 2020 issue of MIT Technology Review.]

      …In a famous essay from the early 1930s called “Economic Possibilities for Our Grandchildren,” Keynes imagined the world 100 years in the future. He spotted phenomena like job automation (which he called “technological unemployment”) coming, but those changes, he believed, augured progress: progress toward a better society, progress toward collective liberation from work….

      Instead of progress toward a labor-free utopia, America has experienced disappearing jobs as a kind of economic climate change. Apocalyptic forecasts loom while poor and working-class communities take the brunt of the early impacts: wage stagnation, deregulated and unsafe workplaces, an epidemic of opioid addiction. The increasingly profligate wealth on the other end of society is no less disturbing….

      Rather than relieving workers from toil, improvements in technology grind out their efficiencies by molding laborers into unreasonable shapes. Across departments, Amazon workers report being forced by the circumstances of their jobs to urinate in bottles and trash cans. Using layers of subcontracting agreements, the largest firms insulate themselves from responsibility to and for their lowest-wage workers. Recent investigations into Amazon’s last-mile shipping reveal exhausted drivers whose required carelessness has, predictably, been known to kill people. The company remains, as far as the business community is concerned, exemplary.

      Everywhere, the idea of liberation from work seems like a dream. Workers making parts for iPhones have been exposed to toxic chemicals; Taiwanese manufacturing giant Foxconn is regularly under the microscope for poor labor conditions….

      …According to the Economic Policy Institute, while worker productivity increased 69.6% between 1979 and 2019, hourly pay has risen a measly 11.6%. “The income, wages, and wealth generated over the last four decades have failed to ‘trickle down’ to the vast majority largely because policy choices made on behalf of those with the most income, wealth, and power have exacerbated inequality,” the EPI says. The difference between produc-tivity and pay is an increase in exploitation: workers doing more and getting less….

      Here all pursue their individual interests, and together that adds up to the best of all possible worlds—at least as long as the government stays out of the way….The trickle-down theory has fared worst of all; the rich pocket, rather than reinvest, their tax cuts.) Most people bought the libertarian hype, and when the global financial crisis hit in 2008, many were surprised to find out markets weren’t actually self-regulating the way they had been told.

      The subsequent bailouts, however, made it difficult to argue that governments could only ever get in the way of the economy’s proper functioning….

      …For Keynes the most dangerous kind of avarice was not trying to make money, but holding it in your pockets for too long….

      …he never identified the mechanism that would end the capitalist accumulation game. Even if we did produce enough stuff to pass the finish line, how would we know? And who's going to make the rich share, or even just stop taking more? He knew that we could keep growing along these lines for only so long, but he ruled out revolution….

      And workers weren’t the only thing Marx saw getting used up: “All progress in capitalistic agriculture is a progress in the art, not only of robbing the labourer, but of robbing the soil,” he wrote. “All progress in increasing the fertility of the soil for a given time, is a progress towards ruining the lasting sources of that fertility.” Environmentalism was not a basic tenet of Marx’s thought, but unlike the economists, he understood intuitively that extractive production had natural limits….

      …In October 2018, the Intergovernmental Panel on Climate Change concluded that global warming is likely to reach 1.5 °C between 2030 and 2052 if temperatures continue to increase at the current rate. In the event we do hit that mark, experts predict a rise of between 26 and 77 centimeters (10 and 30 inches) in sea level, a rapid increase in species extinctions, hundreds of millions more people experiencing water and food shortages, and sustained extreme weather the likes of which the modern human species has never encountered. We have been stockpiling not just wealth, but disasters.

      One protest sign at the youth climate strike put it succinctly: “You’ll die of old age. W’'ll die of climate change…."

      …We need to get the carbon out of the atmosphere and the plastics out of the ocean, keep the oil in the ground and the undomesticated species we have left alive. Anything else is a catastrophic failure….

      The kids recognize that capitalism has been using up human and natural resources rather than building a better society. Rather than a mere reaction to the housing crash and global warming, we can see a deep, emergent understanding. Much to everyone’s surprise, Keynes’s grandchildren have become Marxists….

      Like football, where the increasing size and strength of the players has made brain damage almost certain at the highest levels of the game, capitalist production has become an objective hazard for the entirety of human society….

Knowledge in the Anthropocene

[This excerpt is from a book report by Deborah R. Coen in the 17 January 2020 issue of Science.]

      Can science save humanity? In the face of runaway climate change and massive species extinction, some say that we already know all we need to know to fix these problems: Further research is a distraction and what we need now is action. Others anticipate a feat of technical ingenuity that will catapult us out of our current crisis. In their view, the “Anthropos” of the Anthropocene is well on the way to mastering the Earth system. A middle ground between these positions hardly seems to exist….

      Renn argues that the crisis of the Anthropocene is indeed a problem of knowledge, but he sharply distinguishes himself from those hunting for a technical fix. Knowledge, for Renn, is a broad and varied concept, with crucial experiential and ethical dimensions. Modern science, although uniquely efficacious, is just one facet of the evolution of human knowledge. Understanding this evolutionary process, he argues, is the key to reorienting science for the Anthropocene.

      Taking a cue from biologists, Renn thinks of knowledge as an adaptive system, one that gradually transforms the material and cultural conditions of its own existence. Knowledge evolves through a slow, piecemeal process akin to ecological succession. If we want to guide the future evolution of science, we had better get familiar with its past.

      Renn’s history of knowledge is alternately triumphant and tragic. On the bright side, he traces the development of techniques of representation that have increasingly allowed for reflective engagement with knowledge-making. His foremost example is the internet. With the proper oversight, he proposes, the internet has the potential to “optimize the current knowledge economy toward a global coproduction of knowledge,” building new connections be-tween local stores of knowledge and new opportunities to put knowledge into action. What’s more, science has evolved unprecedented power to reshape the “cultural abstractions” that govern human behavior—as, for instance, in the idea of an ecological footprint.

      Yet this history of modern science is also a story of loss. Market forces have distorted science’s ambitions, diverting it from the humanitarian aims of earlier centuries. The globalization of science has suppressed local forms of knowledge and alienated nonexpert populations. Renn thus returns to the past in part to remind readers of the value of natural knowledge produced in other eras, by a panoply of human cultures, even by nonliterate societies.

      …He argues that modern science, rather than striving to be value-free, should embrace ethical projects of the sort usually associated with religion. Fully aware of the atrocities that could result from turning science into a religion, he nonetheless proposes that we “seek out the eschatological dimensions of science itself and cultivate its role as a guide in a fragile world whose future depends on it.”

      Ours is hardly the first era to witness calls for a wholesale reform of natural knowledge. From Francis Bacon in the 17th century to Vannevar Bush in the 20th, modern science has had its fair share of visionary reformers….

Do Bans Help Modern Public Health?

[These excerpts are from an editorial by Lawrence O. Gostin in the 17 January 2020 issue of Science.]

      …A prohibition on hazardous activities is a blunt tool because products often have both public health risks and benefits. Using illicit drugs is addictive and harmful, but needle exchanges can reduce harms. E-cigarettes can cause acute and longer-term hazards, but they can help cigarette smokers to quit. If government bans a product, it cannot tax it, thus forgoing vital revenues. Lawful marijuana sales in the United States, for example, have financed public services, such as education.

      There are no easy answers, but strict regulation of unsafe products is a more flexible tool ± to decrease behavioral risks, while avoiding social harms (a black market or discriminatory enforcement)….

      Tobacco control offers a paradigmatic case of effective '' rules. A suite of measures, including taxes, age limits for purchasing, marketing restrictions, graphic warnings, and public smoking curbs, has greatly reduced smoking rates….Similar public health benefits could be achieved by controlling other unhealthy products, including alcoholic beverages, “junk” foods, and sugar-sweetened beverages. Taxes, for example, have been shown to reduce consumption of the latter. Gradually reducing sodium in packaged foods could lower hypertension rates.

      Government sometimes criminalizes activities without any evidence of harm….

      Marijuana laws stir public/ controversy, but there is also incomplete evidence regarding the health benefits and harms. Government strategies are inconsistent: U.S. federal law bans all marijuana use, whereas many states allow marijuana for personal use or require a medical prescription. The majority of drug arrests in the United States are for marijuana, and mostly for simple possession. Discriminatory enforcement has led to disproportionate incarceration rates among African Americans.

      Bans have another downside. Researchers can assess the effectiveness of regulations, but once government prohibits an activity, it becomes hard to evaluate….

      Prohibition taught society to be cautious about bans. It is deceptively simple to criminalize a hazardous activity. But bans can create unforeseen social and political risks. The public does not support a government that tells individuals what they can or cannot do for their health. Yet government's greatest responsibility is to safeguard the public’s health. It can do that through a well-regulated society—that is, with evidence-based interventions to “nudge” the public to adopt healthier and safer behaviors.

A Beacon of Hope on Climate Change

[These excerpts are from an editorial by Randi Weingarten in the Winter 2019/2020 issue of American Educator.]

      …One of the foremost purposes of education is to prepare young people for the possibilities and responsibilities of citizenship. This goes way beyond the memorization and regurgitation of facts. Teachers guide their students to develop judgment and discernment to be engaged and empowered participants in society.

      …It’s why we reject lockstep pacing calendars, so we can have extended classroom discussions and debates. Teachers need this latitude to help their students develop the confidence to make their voices heard, the courage to challenge injustice, and knowledge of the levers that can bring about change.

      All this is necessary to prepare this and future generations to address the enormous crises of our age—extreme economic inequality; dangerous assaults on our democracy; polarization, bigotry, bullying, and divisiveness; and…escistential climate change….

      Young Americans have grown up in an age of the earth warming, seas rising, devastating wildfires, and frequent “once in a century” storms. They are taking their future into their own hands. They understand their power to bring about change. But they need people already in power to act now to address the worsening climate crisis. Beyond demonstrations, people must use the political process to change policy.

      Today, even as the focus of the environmental movement has evolved from concerns about pollution to fear of possible extinction, proponents and opponents of tackling climate change largely take their places along party lines. But safeguarding the environment was not always a partisan matter. The Environmental Protection Agency was established during the Nixon administration, and President Richard Nixon planted a tree on the South Lawn of the White House to recognize the first Earth Day. The Senate passed the Clean Air Act in 1970 without a single nay vote.

      In the decades since, environmental regulations and enforcement have helped clean up rivers so polluted with toxins that they once caught on fire, and reduced smog and acid rain. Wind and solar energy are booming. Cleaning up our environment is not a choice between jobs and the environment. As new green technologies show, we can grow the economy, sustain good jobs, and save our planet.

      The disastrous effects of climate change are outpacing policy changes to combat them. Corporations and opponents of government regulations have leveraged their fortunes and influence to undo environmental protections. Communities of color and low-income people suffer disproportionately from environmental degradation and climate change. President Trump has withdrawn from the Paris climate agreement, and his administration has reversed many efforts to safeguard the environment. Trump and his administration have abandoned the once bipartisan leadership of the United States in addressing global climate change.

      People want a better life and a better future. But we need the means. That is why it is so important that individuals—not just the most powerful—have a voice in our democracy. Young voters increasingly name protecting the environment as one of their top concerns. People too young to vote are raising their voices in other ways---walking out in climate strikes, standing up, and speaking out.

      Young people recognize the urgency of the climate crisis that their elders failed to summon. We must join them--pushing for bold political and policy initiatives to reverse climate change and reduce the intertwining issue of economic inequality. Our youth have lit a spark and given us a beacon of hope. We must follow heir lead.

Teaching Climate Change

[These excerpts are from an article by Daniel P. Shepardson and Andrew S. Hirsch in the Winter 2019/2020 issue of American Educator.]

      Heat waves and wildfires in the West, severe storms and tornadoes in the South, intense hurricanes along the coasts, and extreme rainfall and flooding in the Midwest and Great Plains. As more and more people personally experience severe and extreme weather events, they are increasingly likely to believe in climate change. Yet, many still deny or fail to understand how human activity, especially the burning of fossil fuels, is causing global warming and climate change. Thus, there is a need to educate today’s students, tomorrow's leaders and decision makers, about global warming and climate change. It is, however, a challenging subject to teach. This is in part because: (1) climate change is an interdisciplinary subject; (2) it requires students to analyze scientific data and connect it to scientific models; (3) student learning is influenced by prior knowledge and experiences; and (4) it lacks a well-developed conceptual framework and learning progression….

      The scientific community agrees that the earth is warming and that this is due to human activity, primarily the burning of fossil fuels (coal, oil, and natural gas), which alters the atmospheric composition of greenhouse gases. Greenhouse gas emissions, particularly carbon dioxide (CO2), from energy use has increased global atmospheric concentrations of CO2 to historic levels, 412 parts per million. This, in turn, has resulted in an increase in global radiative forcing, caus ing the earth’s average surface temperature to increase by about 1.6 degrees Fahrenheit since the late 19th century….This global warming has caused regional changes in temperature, precipitation, and extreme weather events. In other words, the earth’s climates are changing. Natural climate variations alone, whether due to changes in the sun’s radiance, the earth’s orbit, or volcanic eruptions, cannot account for the degree of warming measured over the last 50 years….

      We should note that global warming and climate change are two distinct phenomena that are closely linked. Global warming refers to the measured increase in the global average temperature of the earth, and this warming is causing the earth's climates to change. Climate change is the statistically significant change in the atmospheric conditions due to human activity, of which global warming is one factor.

      …Weather is the short-term (hours, days, weeks) conditions of the atmosphere described in terms of temperature, precipitation, humidity, wind, cloudiness, visibility, and air pressure. Weather is inherently variable, changing from day to day and season to season, with atmospheric conditions fluctuating naturally within a given range for a specific time and place.

      Climate is the average of this variability in weather for a 30-year or longer time period. It is the “smoothing” of the variation in weather. While the “average” climate is most often talked about, long-term climate data also help us describe the range of expected conditions for a location, the frequency of extreme weather, and the likelihood of certain types of weather events. Climate data are essential for understanding patterns, trends, and changes in our long-term climate. To reiterate, climate change is the statistically significant change in atmospheric conditions due to human activity….

      When it comes down to it, human-driven climate change is really an energy problem. The use of fossil fuels as an energy source results in the emission of CO2 into the atmosphere….CO2 is the key driver of global warming and climate change….

      In 2016, fossil fuels provided about 81 percent of the energy used in the United States, and accounted for about 94 percent of CO2 emissions….

Stick to Science

[These excerpts are from an editorial by H. Holden Thorp in the 10 January 2020 issue of Science.]

      …It turns out that “stick to science” is a tired-but-very-much-still-alive political talking point used to suppress scientific advice L. and expertise….The scientific community should not let this cycle continue because facts that have stood up to, in some cases, years of scrutiny are being suppressed Lin the service of politics….

      The scientific community needs to step out of its labs and support evidence-based decision-making in a much more public way. The good news is that over the past few years, scientists have increasingly engaged with the public and policy-makers on all levels, from participating in local science cafes, to contacting local representatives and protesting in the international March for Science in 2017 and 2018….

      Scientists must speak up. In June 2019, Patrick Gonzalez, the principal climate change scientist of the U.S. National Park Service, testified to Congress on the risks of climate change even after he was sent a cease-and-desist letter by the administration (which later agreed that he was free to testify as a private citizen). That's the kind of gumption that deserves the attention of the greater scientific community. There are many more examples of folks leading federal agencies and working on science throughout the government. When their roles in promoting science to support decision-making are diminished, the scientific community needs to raise its voice in loud objection….

Hush

[These excerpts are from an article by Dorian Fox in the Winter 2020 issue of National Parks.]

      For humans, finding natural quiet — periods of natural sounds without the intrusion of human-made noise — has become increasingly difficult. Today, around 80% of land area in the contiguous U.S. is less than a mile from a road. Tens of thousands of flights hum across the skies each day. In oceans, ships drone, and military sonar pulses. Our phones won’t stop pinging.

      Research has shown that the modern whir not only affects the behavior of wild animals, it’s also making us sick. High noise levels have been linked to heart disease, stroke, sleep disturbance and reduced workplace productivity. A 2011 World Health Organization report suggested that traffic noise significantly cut healthy life expectancy among Western Europeans.

      In recent decades, concerns over the loss of quiet have spurred a growing coalition of ecologists, techni-cians, researchers and advocates to push for change…. first-line artemisinin-based combination therapies (ACTs)….

      A joint study by the Park Service and Colorado State University, published in “Science” in 2017, found that manmade noise doubled background sound levels in a majority of U.S. protected lands and caused a tenfold increase in 21% of those lands. Also, in 12% of wilderness areas — which make up 53% of the park system and are the most protected public lands in America — noise pollution doubled natural ambient sound levels….

Long Live the KIng

[These excerpts are from an article by Nicolas Brulliard in the Winter 2020 issue of National Parks.]

      …While monarchs can still appear in any suitable backyard or meadow, the likelihood of spotting one is not what it used to be. Populations fluctuate from year to year, but overall numbers have been on a steady downward trend over the last couple of decades. The decline has been particularly pronounced among monarchs that overwinter on the California coast; their numbers i have dropped more than 99% since the 1980s….

      In 2014, the Center for Biological Diversity…filed a petition to list the monarch as a threatened species under the Endangered Species Act. The U.S. Fish and Wildlife Service has put off making a decision on the petition until late 2020. The petitioners agreed to the delay so that the latest data could be taken into account….

      …warming temperatures have added to the woes of the butterflies, which have at times migrated north before the emergence of the milkweed, the only host plants for monarch caterpillars. Moreover, while monarchs have always been sensitive to weather fluctuations, extreme events such as unseasonal cold snaps are becoming more frequent and can have devastating effects. Since 2002, winter storms have decimated the population of monarchs overwintering in the mountains of central Mexico on four separate occasions….

      Habitat loss to development and agriculture is also contributing to declines in the monarch population. That problem, which isn’t new, has been compounded by the planting of genetically modified corn and soybean crops, which have been engineered to resist glyphosate herbicides. These herbicides kill pretty much everything else, including milkweed. In addition, a federal mandate to boost the production of plant-based fuels has led to the destruction of millions of acres of grasslands….

Mussel Power

[These excerpts are from an article by Rona Kobell in the Winter 2020 issue of National Parks.]

      Washington, D.C., recently welcomed some new neighbors — about 8,700 of them.

      That’s how many mussels just were released into the Anacostia River. And residents will have to get used to them because thousands more are on the way. The adjustment shouldn't be too taxing since the new arrivals are there to be upstanding community members: They are serving as the latest reinforcements in the decades-long battle for cleaner water in the meandering 8.4-mile river.…

      Like their bivalve cousins, the oysters, mussels filter excess pollution that comes off the land — either from farm fields, sewage treatment plants or storm runoff. Some urban areas, including New York City, have turned to oysters to filter their waterways and build reefs to boost resilience to storms. But the fresh waters of the Anacostia aren’t suitable for oysters….

      …High concentrations of heavy metals, chemicals and sediment can kill mussels, but if the conditions are right, the mollusks absorb excess nitrogen and phosphorus and settle sediment. The hope is that with the mussels on the job, the Anacostia’s waters will be clearer and aquatic grasses will prosper, creating additional habitat for all manner of creatures. In addition, if all goes well, the new mussels will help revive the population that was already there, increasing their impact….

      A cleaner waterway benefits nearby neighborhoods, wildlife and the public lands along the river….

Our Tiny Inner Pharmacists

[These excerpts are from an article by Claudia Wallis in the January 2020 issue of Scientific American.]

      Next time you swallow a pill, think about this: you may not be the only one digesting it. You might not even be the first. By now most people are aware that our gastrointestinal tract is teeming with microbes that live mostly in harmony with us, helping us break down food, synthesize vitamins, resist germs, and relay chemical signals to our brain and immune system. But an emerging field of research with a mouthful of a name—pharmacomicrobiomics—is demonstrating that our tiny inner denizens can process our drugs in ways that both help and harm us….

      Microbes can also sabotage the classic cardiac drug digoxin, which is used to treat arrhythmias and heart failure. Doctors have long known that about 10 percent of patients who take it do not benefit, because so much of the drug—more than 50 percent in some cases—is inactivated by a gut bacterium called Eggerthella lenta….only a few specific strains of E. lenta have this talent.

      Our inner microbes can work in our favor, too. The drug sulfasalazine, widely used for rheumatoid arthritis, Crohn’s disease and ulcerative colitis, does nothing unless gut bacteria metabolize it into an active form by breaking a chemical bond. This is also true of multiple oral antibiotics in the class known as sulfa drugs.

      Another drug that gets a microbial helping hand is metformin, the first-line medication for type 2 diabetes. In this case, it’s more of a two-way interaction. Recent studies show the drug somehow alters the mix of gut microbes in ways that make metformin more effective….

      Perhaps the most exciting work in this nascent field concerns irinotecan, used as part of a cocktail of drugs to fight advanced colon and pancreatic cancers. Irinotecan is a powerful killer of tumor cells but provokes such severe diarrhea and intestinal damage that many patients cannot tolerate enough of it to treat their disease—a phenomenon known as dose-limiting toxicity. Chemist Matthew Redinbo of the University of North Carolina at Chapel Hill has traced the issue to a family of bugs called Enterobacteriaceae (members include Salmonella and Escherichia coil). The drug, given intravenously, circulates to the tumor and gets tagged for excretion in the liver, where it is rendered harmless by the addition of a simple sugar. Unfortunately, Redinbo explains, “microbes love sugar” so when the neutralized drug hits the GI tract on its way out of the body, the bugs pick off the sugar, reactivating the toxic drug, which then proceeds to “rip the GI tract apart.”

      Motivated in part by a young colleague’s battle with colon cancer and with irinotecan's side effects, Redinbo has developed a small molecule that stops the microbes from eating the sugar so that the drug passes harmlessly through the gut….

      If Redinbo and his colleagues succeed, they will have opened the door to a class of drugs that can modify microbes with great precision….

Neighborhood Threats

[These excerpts are from an article by Melinda Wenner Moyer in the January 2020 issue of Scientific American.]

      Over the past five decades mosquito populations in parts of the U.S. have skyrocketed by a factor of 10—a situation with worrying implications for the spread of diseases such as West Nile virus, dengue and chikungunya. And some places are apparently more nerable than others. A new study…found that in Baltimore, low-income neighborhoods bear the biggest burden: they have not only more mosquitoes but also larger ones, which often survive longer. The problem most likely is rooted in the fact that Baltimore has nearly 17,000 abandoned buildings, which are concentrated in economically disadvantaged areas and serve as convenient mosquito-breeding zones. To effectively combat mosquitoes and the diseases they carry, the study suggests, cities Iwill need to account for urban infrastructure.

      …Aedes albopictus (better known as Asian tiger mosquitoes)…, introduced to the U.S. in 1987, is now the most common in many American cities. When the researchers measured the mosquitoes’ wing lengths, a proxy for body size, they found that the insects grew larger in lower-income blocks. Bigger mosquitoes are not just a bigger annoyance: the larger they are, the longer they tend to live—and the more times each one can bite. Because mosquitoes have to bite at least once to become infected with disease-causing microorganisms and again to pass them on to people, bigger mosquitoes could pose higher disease risks. Larger mosquitoes also lay more eggs, setting the stage for higher numbers later on….

      The researchers say low-income blocks produce more and larger mosquitoes because they have more abandoned buildings than affluent blocks do and are more heavily littered with discarded containers that collect standing water. And water that pools in degraded buildings is protected by shade—which helps mosquitoes grow larger. Some cities' well-intentioned efforts to plant trees in low-income blocks may worsen the problem: trees and shrubs not only shade outdoor breeding pools but also shed leaves into the water and feed the mosquito larvae, helping them grow bigger….

      Fortunately, mosquito borne diseases are not a massive problem in the U.S. for now. From January through October 2019, the Centers for Disease Control and Prevention reported 777 cases of West Nile virus and 614 cases of dengue (and most of the latter occurred in people infected outside the U.S.). But climate change could worsen the country’s disease landscape by broadening habitats and lengthening the time every summer that mosquitoes can breed and survive.

      …And low-income areas affected by natural disasters such as hurricanes can also become mosquito-breeding grounds. Research has shown that disasters disproportionately damage low-income housing, which also tends to be rebuilt slowly, if at all.

      Cities may, then, need to focus more mosquito-control efforts on these areas. Urban health departments typically educate homeowners about the importance of emptying water out of outdoor containers such as pet bowls, as well as trash and recycling bins. But nobody empties such receptacles in or around abandoned buildings, and so far most municipalities have not been willing to take on the job….

Time’s Up for “Anti-Gay Therapy”

[These excerpts are from an editorial by the editors in the January 2020 issue of Scientific American.]

      …The reason no minor should be subjected to this practice has nothing to do with partisan politics or religious beliefs. The putative therapy should be discarded because it is rooted in bad science. Its origins are tied to both rejected concepts about sexuality and therapies based on those discredited notions.

      Homosexuality—once explained erroneously as the result of an overbearing mother—was classified as a form of mental illness in psychiatry's first diagnostic manual, published in 1952. In the past, treatments to “cure” it included electroshock, chemical therapies such as the forced hormone treatments infamously inflicted on British mathematician Alan M. Turing, and the hiring of prostitutes for “behavioral” interventions. But milder versions persist today in the form of aggressive counseling and, at times, the administration of measures that induce nausea or vomiting.

      Trying to alter an individual’s sexual identity should be banned simply because of the irreparable harm it causes….

      The medical establishment, thankfully, has become a solid critic of anti-gay conversion. The American Medical Association, the American Psychological Association and other organizations characterize it as useless and injurious. The public is also opposed: a 2019 Reuters/Ipsos national poll found that 56 percent of U.S. adults think conversion therapy should be illegal.

      Although medical and psychological associations have asked explicitly that Congress and state governments ban anti-gay conversion, there has been a backlash from groups such as the Liberty Counsel, which promotes ”evangelical values….”

Asimov at 100

[These excerpts are from an article by James Gunn in the 3 January 2020 issue of Science.]

      The year 1939 was also when Asimov’s first science fiction story was published in the magazine Astounding Science Fiction. The sale of his stories paid for his college expenses, including the master's degree he would later earn in chemistry (He was rejected twice for medical school but would go on to earn his doctorate, again in chemistry.)

      In 1942, Asimov began research as a chem-ist at the Philadelphia Navy Yard. Meanwhile, he continued to sell stories but considered himself a third-rate writer until his novelette “Nightfall” received a cover story in Astounding Science Fiction in 1941. The following year, the first story of his Foundation series was published. During this period, he began the first of his robot stories, which were published together in 1950 as I, Robot….

      Kurt Vonnegut is reported to have once asked Asimov how it felt to be the man who knows everything, to which Asimov is said to have replied that he only knew how it felt /to have the reputation of omniscience….

      A case can be made that, like H. G. Wells, Asimov came along at the right time. (Wells once commented that he made his writing debut in the 1890s, when the public was looking for new writers.) But Asimov also had a restless and productive mind. His early experience of reading, and then writ-ing, science fiction gave his popular science writing a rare narrative model, while his fiction similarly benefited from his scientific training.

      Some of Asimov’s critics complained that his writing lacked style. He responded by asserting that he had a style: clarity. But it also was true that he was able to adopt new methods, particularly in his later works.

      Asimov’s fiction was based on the presumption that humanity would solve its problems by thinking coolly and logically. In his nonfiction writing, he often grappled with the messier realities of human nature. There are no records of how many minds he influenced with the latter, but his ability to communicate difficult scientific es. ideas in simple language has not been equaled since….

Study Pushes Emergence of Measles Back to Antiquity

[These excerpts are from an article by Kal Kupferschmidt in the 3 January 2020 issue of Science.]

      …Measles, which killed an estimated 142,000 people in 2017, is one of the most infectious human diseases. But when, where, and how it became a human pathogen is still debated. The closest relative of the measles virus is one that causes rinderpest, a disease that affected cattle, deer, buffalo, and other even-toed ungulate species before it was eradicated in 2011. Most researchers believe both viruses had a common ancestor that infected cattle….

      Because measles spreads so fast and infection confers lifelong immunity, scientists estimate it needs populations of 250,000 to a half-million people to avoid burning itself out. Historians believe that the largest cities reached that size around the fourth century B.C.E. But when researchers in Japan used available genomes of the measles and rinderpest viruses to build a phylogenetic tree, enabling them to date the branches, they concluded in 2010 that measles didn’t emerge until the 11th or 12th century C.E.

      The uncertainty stems in part from a surprising lack of historic sequences. Only three genomes from measles viruses occurring before 1990 are known; the oldest is one isolated in 1954 that was turned into the first measles vaccine. So Calvignac-Spencer turned to the Berlin museum, whose shelves are filled with thousands of tissues and organs floating in formalin-filled glass cases, like aquariums of human anatomy.

      Formalin fixes tissue by cross-linking proteins and other large molecules, including RNA, which the measles genome is made of. To extract RNA from such samples, scientists use techniques pioneered about 10 years ago by cancer researchers interested in formalin-fixed biopsies….

      Calvignac-Spencer’s team drew up a new phylogenetic tree using the 1912 genome as well as a new one from 1960, pieced together from a sample in another collection, and other available genomes. The resulting tree suggests the disease could have jumped to humans as early as 345 B.C.E.--- right around the time human populations reached the critical size.

      The earlier date for measles' emergence also reflects the models that the team used to analyze the viral sequences. When drawing up a family tree using differences in genomes, researchers must estimate the speed at which viral genomes diverge. In the past, their estimates were often too high, because some deleterious mutations tend to disappear over time. The new model accounts for this effect, called purifying selection. It pushes back the divergence of measles and rinderpest even without including the 1912 genome. But the genome strengthens the new timeline, Calvignac-Spencer says.

      The researchers can’t rule out that the measles virus first circulated in humans and then jumped to cattle, but that seems unlikely….And the closest relative of the two viruses, which is even older, causes peste des petits ruminants, a sheep and goat disease that probably crossed to cattle more easily than to humans….

The Higher Education Crisis

[These excerpts are from an article by Maria Ferguson in the December 2019/January 2020 issue of Phi Delta Kappan.]

      For most high school seniors (and their long-suffering parents), the holiday season is definitely not the most wonderful time of year. Soon-to-be graduates are deep in the throes of trying to figure out their next steps after graduation while their parents are busy trying to navigate costs, expectations, and lots of drama. Although not all students plan to attend college after high school, more students are pursuing a college education than ever before….almost 20 million students attended either a two- or four-year college this past fall, the highest enrollment rate ever.

      While the road to college is not easy for anyone, it can be especially challenging for low-income students. A recently released book about college admissions and the pursuit of equity in higher education sheds light on just how fundamentally inequitable thigher education can be….

      …Paul Tough…focuses on the unsavory truths about the college admissions process and how it undermines efforts to make higher education more Laccessible to low-income students….

      Tough hones in on issues many of us know well: the lingering inequities of standardized tests like the SAT and ACT; the outsized influence of the U.S. News and World Report college rankings; and the almighty algorithms that help ensure colleges and universities always meet their tuition targets. Taken together, these powerful forces form a virtually insurmountable elitist wall around higher education that calls into question the very nature of how institutions assess a student's performance and potential. We all may want to believe that U.S. education is a meritocratic endeavor, but the facts on the ground indicate otherwise. Starting with the admissions process and continuing right on through their years on campus, the inequities students of color and those who come from poverty face are formidable.

      …the College Board made a range of free test-prep resources available online after studies showed that wealthier students had a competitive edge because of the many test-prep resources their families could afford….

      …Months (years!) of discussions and negotiations have not produced any meaningful results, and the general atmosphere on the Hill is, well, not conducive to compromise….

      All of this inaction is playing out against a backdrop of mounting student debt. According to the Federal Reserve, student loan debt in the U.S. has now reached $1.6 trillion. When the words “trillion” and “debt” are used in the same sentence, one would think it is time for serious action, but the Trump administration seems to believe otherwise. Aside from a plan floated earlier this year to cap student loans (an idea most experts agree would do little to address the root causes of the debt crisis), the administration has offered no real plan to address the crisis. The one concrete step the administration did take actually works against students who are trying to avoid the curse of student debt. Earlier this year, Secretary of Education Betsy DeVos repealed the Obama-era gainful employment rule, which was developed to better protect students from predatory for-profit education providers. With its repeal, the secretary actually made it easier for profit-hungry education providers to take advantage of unwitting students.

      When looking at all these issues comprehensively, it’s hard not to believe U.S. higher education is a hot mess. But should we expect anything different when our nation’s level of income inequality is at an all-time high?...Looking ahead, it seems that if our country has indeed evolved into a knowledge-based economy, then we better get our act together when it comes to making higher education a feasible goal for most students. But righting this ship is going to take leadership, vision, and commitment, none of which seems to be present within the current administration and Congress. We have an opportunity in 2020 to bring some new ideas and energy to the problem. Let's hope U.S. voters help deliver us from this mess we are in.

Student Growth Measures: What We’ve Been Missing

[These excerpts are from an article by Doris A. Santoro in the December 2019/January 2020 issue of Phi Delta Kappan.]

      …However, NCLB [No Child Left Behind] possessed at least one major blind spot: It did little to measure students' actual academic growth. By punishing and rewarding schools on the basis of a narrow definition of proficiency — whether their students were mastering grade-level content — the law neglected other key indicators of student learning, such [as] how much progress students were making on other standards. As a result, the entire educational ecosystem, including class-room instruction, was oriented around a single and very limited measure of student performance.

      President Barack Obama’s modified version of NCLB, the Every Student Succeeds Act (ESSA), took a step to correct this problem by directing states to capture student “growth or another valid or reliable measure” as part of their accountability systems. For many, this was a positive development. In the stakeholder meetings held throughout the country to help guide the decision making for ESSA, representatives from 48 states told the Obama administration that it was important to measure growth more accurately.

      …current assessment and accountability sys-tems still fail to measure how much students actually learn….all states are still testing students and measuring instructional effectiveness on the basis of grade-level performance. As a result, these assessments measure only a slice of student learning and cannot precisely demonstrate how much or how little a student has learned. It’s like an iceberg, where only a very small amount of information is visible, while the bulk of the information remains hidden from view. Our accountability and assessment systems unfortunately measure just one tiny portion of students’ knowledge. Meanwhile, the real truth of what students are learning — or not learning —remains hidden. Because assessments and accountability focus narrowly on grade-level proficiency, teachers tend to focus their instruction only on grade-level proficiency, instead of meeting students where they are….

The Problem with Stories about Teacher “Burnout”

[These excerpts are from an article by Doris A. Santoro December 2019/January 2020 issue of Phi Delta Kappan.]

      The expressions of concern about teacher burnout correctly imply that something is amiss in many of our public schools….If teachers are burning out, it is because they are asked to do too much with insufficient support and low salaries; school resources do not come close to meeting students’ needs; and reform efforts come fast and furious, without enough time for anyone to adjust, implement, assess, and reflect.

      And yet, calling it “burnout” tells the wrong story about the kinds of pain educators are experiencing because it suggests that the problem lies within individual teachers themselves. To say they've burned out is to portray them as weak and exhausted, defeated by the pressure, with little hope for rejuvenation. Not only does this diagnosis lead policy makers to prescribe ineffectual remedies, but it likely contributes to the more significant problem I call teacher demoralization.

      …But as I use it, the term describes teachers’ feelings about the moral and ethical challenges they face. Many teachers become dissatisfied not because they’re exhausted and worn down but because they care deeply about students and the profession and they realize that school policies and conditions make it impossible for them to do what is good, right, and just.

      …If the work cannot be done ethically, then its social value and purpose are compromised, and its practitioners, such as teachers, become demoralized.

      As a teacher educator and public school advocate, I question the idea that teachers leave simply because they've burned out. The better and more accurate story is that teachers want to engage in good work that benefits students, communities, and the profession, and they become frustrated when they cannot do so. Like the story about teacher burnout, the story of teacher demoralization can be depressing because it acknowledges that many educators are unhappy with their jobs and have considered leaving the profession. But, unlike the burnout narrative, it allows for hope and possibility. To say that teachers are burned out is to imply that they are spent and done. However, to say that they are demoralized is to acknowledge that they remain passionate and energetic and would love to be given opportunities to teach in ways that are just and good….

Helping Preservice Teachers Separate Fact from Fiction

[These excerpts are from an article by Jeremy Delamarter in the December 2019/January 2020 issue of Phi Delta Kappan.]

      …Almost from the moment we are old enough to recognize the world around us, we are bombarded with images of teachers and teaching. They are in the books we read, in the childhood games of toddlers, in newspapers, and in magazines. Images of teachers “spill out into television studios, movie theaters, homes, and playgrounds, infiltrating all arenas of human activity….”

      This same hand-me-down phenomenon happens with preservice teachers. Like the rest of us, aspiring teachers have been saturated with images of teachers and classrooms.

      On one hand, these images of teaching can paint teaching in a flattering and inspiring light that can draw people into the profession. Teacher movies, for example, are essentially scripted highlight reels, showcasing three or four pivotal moments over the course of a year foregrounding relationship building and, often, racial catharsis. The teacher is the hero, the cowboy of the Wild West riding into town to save the day. No one cares for the students like this teacher does, and, consequently, his or her students’ lives are changed forever. The familiar tropes of the Hollywood teacher movie are well-worn and comfortable. Despite the fact that numerous studies have documented just how unrealistic these portrayals often are…, their appeal is undiminished, and people are often drawn to teaching in part because of these films’ implicit promises that teachers can singlehandedly change students' lives.

      On the other hand, these same images of teaching can lead to frustration and emotional turmoil, especially when new teachers enter the field and begin to face the realities of classroom practice. Our cultural images of teachers are too often one-dimensional, fictionalized accounts of a fantastically complex three-dimensional reality. In the movies, good teachers often begin the year by discarding standards-based instruction in favor of “life lessons” — there may even be a scene where the teacher literally throws the curriculum away. Imagine the fate of the new teacher who enters the classroom convinced that it’s more important to teach students to love math than it is to make sure that they can do math.

      Although changing students’ lives and fostering academic excellence are not mutually exclusive goals, the images of teaching that surround us often insist that teachers must, in fact, choose between them….

      Secondhand images of teaching are not the only shadows that get mistaken for reality, however. Even preservice teachers' own firsthand experiences as K-12 students can lead to unrealistic and incomplete expectations of teaching. Time spent in classrooms as students does not, in and of itself, prepare one for the realities of teaching. Though preservice teachers may have spent much of their lives observing their own teachers in action, the picture they have is incomplete….

      Even the most attentive K-12 student does not have access to what takes place behind the scenes. Students don't observe the meetings, trainings, and other collaborative activities that constitute much of a teacher's work. They don't see the planning, grading, or any of the other countless steps that it takes to implement effective instruction. They witness neither the self-doubt that accompanies a failed lesson nor the frustration of explaining the same thing for the third time in a row.

      …Because students don’t think like a teacher thinks, they don’t recognize the intentionality and structure behind much of what takes place in a well-run classroom. They experience it, but they don't necessarily see it for what it is.

      …Creating a thriving teacher workforce requires a willingness to guide future teachers through the sticky work of reconciling their expectations with reality. Closing the expectation gap is not supplemental to basic teacher education; it is a necessary step in the process of becoming a teacher. It is not enough for aspiring teachers to learn something new; they have to become something new, as well.

Telling New Stories about School

[These excerpts are from an article by Sarah M. Stitzlein and Kathleen Knight Abowitz in the December 2019/January 2020 issue of Phi Delta Kappan.]

      The stories we tell about schools influence our collective imagination about what schooling is and can be. They are much more than just tales we tell; they actually shape our pV beliefs and the realities that result from them….

      When we tell the story that going to school and working hard is the path to a good and lucrative job, we are promoting a set of beliefs that may lead to specific actions and outcomes, such as seeking a school that maximizes one's money-making potential. And so those stories mold the educational landscape through the policy makers we select (those who promise a strong return on our taxpayer investments in schools); the sorts of schools we offer (those aimed at preparation for well-paid careers, especially in areas high in social and economic capital); and the ways we go about assessing their quality (through tests that weed out poor-quality teachers and distinguish the best and brightest students). Our stories about education matter; they shape our preferences in the voting booth and actions on educational policies. They produce real political out-comes….

      Narratives celebrating economic aims are not new Americans have long emphasized the economic aims of education, whether those be earning certifications that lead to lucrative employment or inculcating the skills needed to succeed in a hierarchical marketplace….Since the late 19th century, business and education leaders have often been united in their expression of the idea that schools would be viewed as irrelevant and even wasteful if they could not directly link education to future job preparation and outcomes….

      Those advocating for market-based approaches tell stories with a purpose. And their stories are powerful in part because they obfuscate the interests and ideologies at play behind them. An image of happily selecting a school from an array of good choices — much as one does when selecting cereal — emphasizes the power of the consumer, but not the monetary benefit to those whose product is selected, or the harm to those who were left behind or unable to make the same choices. Policy makers…can employ such stories about school choice to increase privatization, reduce government oversight, and advance market-based reforms. Such stories have agency; they are not neutral, but rather act to bring about change, often working with the interests of school privatizers….

      …The current choice-based climate is replete with narratives that foster little reflection on public schooling's value as a public institution, its role in sustaining democracy, or its history of working to bring equal educational opportunity to more chil-dren — all of which are key aspects of the common school model and its democratic aims in early America.

      …If citizens want to shape schools with democratic purposes in mind, citizens and public education advocates need to intentionally craft new stories about present and future policy choices, resisting narratives of competition and the individualistic values driving them. Telling new stories that foreground the public or shared purposes of public education may lead us to choose candidates and back policies that better serve our children and our communities.

      …a parent who deems childrens' happiness as important may decide to support a school levy or budget to fund extracurricular activities that bring children joy, even though it is costly to taxpayers and may not deliver specific job skills….

The Toxic Twin

[These excerpts are from an article in the Winter 2020 issue of Rotunda, the member magazine of te American Museum of Natural History.]

      Our planet Earth has a twin: Venus. The second planet from the Sun and our immediate neighbor has astoundingly similar qualities to our own world. It's close in size and mass, with an internal iron core and silicate mantle and crust. Its dense atmosphere has active weather-like phenomena.

      This world also once had conditions that were very similar to those of early Earth. For 2 to 3 billion years, an active volcanic surface carved out vast plains and a mountainous landscape. Average temperatures ranged between 68 and 122 degrees Fahrenheit, and there may have even been shallow seas filled with liquid water.

      But around 700 million years ago, when multicellular life was flourishing on Earth, large amounts of carbon dioxide filled Venus' atmosphere. Today, its punishing conditions are in stark contrast with those of our own blue-and-green Earth, with its perfect setting for hosting life. Why did these two worlds diverge?

      More than 40 spacecraft have visited Venus through the years, starting with the U.S.. Mariner 2 in 1962. Currently, the Japanese mission Akatsuki is in orbit around Venus, studying atmospheric weather patterns such as the presence of lightning and looking for active signs of volcanism on the surface. But it was NASA’s Magellan mission, from 1989 to 1994, that marked a turning point in our understanding of what was then a still-“elusive” planet.

      When scientists received the first high-resolution images of the Venusian surface captured using Magellan’s Synthetic Aperture Radar “they whooped with delight at the astonishing detail captured by the spacecraft’s radar eyes,” according to The Washington Post.

      Magellan showed that Venus’ mysterious surface is complex and unique. It features thousands of volcanoes, a uniform distribution of craters formed through violent impacts of meteorites, and deep channels and wide valleys formed by ancient lava flows.

      But it’s now been 25 years since we last took a close look at Venus’ surface….

      When we do return, we’ll need to send robots in our stead. While Venus has a gravity similar to Earth's, the conditions on the ground would be deadly for human explorers. Its atmosphere is almost entirely made up of carbon dioxide, so thick that the pressure on the human body would feel like swimming 3,000 feet below the oceans’ surface. Venus, which is closer to the Sun than Earth by 26 million miles, also receives about twice as much sunlight per day.

      There’s another invisible but vital difference between Venus and Earth—a magnetic field.

      On Earth, the magnetic field created by our planet’s churning liquid iron core acts like a shield, deflecting solar wind particles. Venus, by comparison, rotates at an extremely slow rate, which is likely why it never formed a magnetic field. Without this powerful barrier against solar winds, its shallow seas dried up. With its water finally stripped away, the buildup of carbon dioxide in Venus’ atmosphere reached a point of no return, trapping solar energy as scorching heat. Temperatures soared to nearly 900 degrees Fahrenheit—hot enough to melt lead—and created thick, toxic clouds of sulfuric acid that move so furiously they circle the planet every five days….

Engineering Life

[These excerpts are from an article by Jonathan Shaw in the January/February 2020 issue of Harvard Magazine.]

      Synthetic biology, or the application of engineering principles to the design of life, presents world-changing prospects. Could components of a living cell function as tiny switches or circuits? How would that allow biomedical engineers to build biological “smart devices”—from sensors deployed inside the body to portable medical kits able to produce vaccines and antibiotics on demand? Could bacterial “factories” replace the fossil-fueled industries that produce plastics, foods, and fertilizers? Will the secrets of living creatures that enter suspended animation during periods of drought and extreme cold be harnessed to keep human victims of trauma alive? And is the genetic information preserved in long-frozen or fossilized extinct species, like woolly mammoths, sufficiently recoverable to help save living species?

      These ideas, once the stuff of science fiction, are now the stuff of science. Some aren’t yet functioning realities, but others have launched business applications, whether in medicine (such as hospital gowns that signal exposure to infection) or in land remediation (where bacterial “factories” powered by the sun capture nitrogen from the atmosphere to help plants grow). Someday, engineered forms of life that store carbon may even be one of the solutions to Earth’s climate-change problem….

      Propelling the science forward are scores of innovations in biological science, with new discoveries coming every month. Among the most important are advances in genetic editing, including improvements in accuracy, and the ability to make hundreds of changes at once. Another is computer-aided design, widely used to model biological systems, and to build new proteins by combining amino acids in ways never seen in nature. Advances in molecular engineering are driving the construction of ever-more complex circuits made from biological materials. And the ability to freeze-dry cellular transcription machinery outside the confines of cells has enabled scientists to easily manufacture proteins at will, at any time and place….

      Many of the earliest biological switches were crude and prone to accidental triggering. The inside of even a single-celled bacterium such as E. coli, where engineered synthetic circuits are often introduced and tested, is very busy….

      Agriculture is one area of critical need: a growing world population must be fed….devised a process to manufacture inexpensively one of the most energy-intensive products farmers use: fertilizer, which provides the nitrogen that plants need to grow.

      The work builds on an artificial leaf…that harnesses solar energy to split water (H2O) in order to produce hydrogen, an energy source. To create fertilizer, Silver helped connect the artificial leaf to a strain of bacteria that can “fix” both atmospheric carbon dioxide and nitrogen, converting them to organic forms that can be used by living organisms. Provided with an unlimited supply of hydrogen from the artificial leaf, the bacteria combine the hydrogen with carbon pulled from the atmosphere to create a solid fuel that the bacteria store internally, as a long-term energy supply….

      The bacteria are then mixed into the soil, where some remain, and others form associations directly with plant roots. Drawing from their stored energy reserves, they begin fixing atmospheric nitrogen, thus fertilizing the plants. (Because the carbon in the bacteria remains sequestered in the soil even after the bacteria deplete their energy stores and die, the process has the added advantage of being atmospheric carbon-negative.) On test fields, Nocera reports “big increases in crop yields” with almost no run-off, an environmentally poisonous side effect of water-soluble chemical fertilizers….

(Re)New and Improved

[These excerpts are from an article by Sarah Nightingale in the Winter 2019 issue of USC Trojan Family.]

      …Their guide on this behind-the-scenes tour, a local restaurant owner, points to what they've been looking for: a grease-splattered metal container filled with used cooking oil….

      Trying not to draw unwanted attention—they’re not there to steal anything, and questions would just slow them down—he snaps a few pictures of the grease traps. He is careful to capture the contact information for the company that promises to empty them.

      You might ask why two USC researchers care where greasy spoons dump the contents of their deep-fat fryers. The simple answer lies in the power of chemistry. They’re finding ways to transform that waste product into a much-needed renewable fuel—and make the world a cleaner place.

      …These researchers are giving a second life to byproducts and discarded materials, employing recycling and upcycling to keep waste out of landfills. Oftentimes these processes reduce the need to manufacture materials from scratch, cutting down on greenhouse gas emissions and water pollution. Ultimately, their work has a modest but increasingly important goal: to get the most out of resources with the minimum amount of waste.

      The world has a trash problem. People toss out more than 2 billion tons of garbage each year according to a World Bank report. The Environmental Protection Agency reports that the U.S. share of that pile is 262 million tons per year. Paper makes up most of it, followed by food, yard trimmings and plastic.

      The recycling of discarded plastic—which can take 1,000 years to decompose—peaked at about 9% in 2018, with the rest diverted to landfills and incinerators or simply left on the ground. That unimpressive figure nose-dived a year ago when China, long the world’s biggest importer of recyclable waste, opted out of the plastics recycling business. It feared being overwhelmed by other countries’ trash. While scientists and policymakers have contemplated creative solutions to disposing of humanity’s garbage, including launching it into space, the down-to-earth solution likely involves creating fewer single-use products and reusing the materials in the goods we do make.

      …They knew of the potential of biofuels, which burn cleaner than their petroleum-based counterparts and may reduce our dependence on foreign oil, according to the U.S. Energy Information Administration. One problem is the cost of making biofuel—an issue that has thwarted the biodiesel industry for decades. While soybeans are the biggest source of oils for the industry, the combined energy needed to grow them, extract their oils and use the oils to make biodiesel is too expensive to compete with the petroleum industry. Starting with waste cooking oil reduces the cost, but not enough to make it profitable….

      As Williams explains, the most common way to turn vegetable oil into biodiesel is a chemical reaction that produces glycerol as a byproduct. But glycerol has little use, so it’s cheap. If they’re lucky, biofuel manufacturers can sell it for a few cents per pound to livestock producers, who spray it on the ground to keep dust down. In Southeast Asia, many producers dump it into rivers….

      At USC Loker, Lu discovered a way to convert glycerol into something valuable: sodium lactate. Used in the food processing industry, the market for this non-toxic, environmentally friendly chemical is $1.5 billion and growing….

      Increasingly used by commercial air-craft manufacturers like Boeing and Airbus, carbon fiber reinforced polymer composites consist of long woven strands of carbon fibers combined with a matrix, or resin. The material’s structural marriage offers exceptional strength without substantial weight, making the composites popular for airplanes and other vehicles. Composites account for half of the weight of the world’s best-selling passenger plane, Boeing’s 787 Dreamliner, and the carbon composite chassis of BMW's popular i3 electric car is so light it can easily be lifted by two people. Compared with traditional manufacturing materials—even lightweight metals like aluminum—the weight savings offered by composites make a tangible difference in fuel efficiency.

      But there are downsides to composites: their cost, the wasteful manufacturing process and their resistance to traditional recycling….

      The process…involves cutting scraps of composite sheets into thin strips of various shapes and sizes, pressing them in molds and heating them to form new composite parts. It’s a concept he likens to the production of plywood or fiberboard.

      …While the new sheets won’t be used as major load-bearing structures in airplanes in the near future, the reclaimed composites can be crafted into structures in planes that bear less of a load, like dividers, seats and luggage compartments. They can be used for cars and buildings, too….

The Chicxulub Asteroid

[This excerpt is from chapter 9 of The Rise and Fall of the Dinosaurs, written by Steve Brusatte in 2018.]

      What happened on that day—when the Cretaceous ended with a bang and the dinosaurs' death warrant was signed—was a catastrophe of unimaginable scale that, thankfully, humankind has never experienced. A comet or an asteroid—we aren’t sure which—collided with the Earth, hitting what is now the Yucatan Peninsula of Mexico. It was about six miles…wide, or about the size of Mount Everest. It was proba-bly moving at a speed of around 67,000 miles per hour…, more than a hundred times faster than a jet airliner. When it slammed into our planet, it hit with the force of over 100 trillion tons of TNT, somewhere in the vicinity of a billion nuclear bombs’ worth of energy. It plowed some twenty-five miles…through the crust and into the mantle, leaving a crater that was over 100 miles…wide.

      The impact made an atom bomb look like a Fourth of July cherry bomb. It was a bad time to be alive.

Tyrannosaurus rex

[This excerpt is from chapter 6 of The Rise and Fall of the Dinosaurs, written by Steve Brusatte in 2018.]

      T. rex was able to gnash through most anything that it wanted to eat, whether it was splurging on a forty-foot-long Edmontosaurus or snacking on smaller contemporaries like the donkey-size ornithischian Thescelosaurus. But how did it capture its food?

      Not, as it turns out, with exceptional speed. T. rex was a special dinosaur in many ways, but one thing it could not do is move very fast. There’s a famous scene in Jurassic Park where the bloodthirsty T. rex, convulsed by its insatiable appetite for human flesh, chases down a jeep driving at highway speeds. Don’t believe the movie magic—the real T. rex likely would have been left in the dust once the jeep got up to third gear. It’s not that Rex was a plodding slouch that waddled through the forest. Far from it—T. rex was agile and energetic, and it moved with purpose, its head and tail balancing each other as it tiptoed through the trees, stalking its prey. But its maximum speed was probably in the ballpark of ten to twenty-five miles per hour. That’s faster than we can run, but it’s not as quick as a racehorse or, certainly, a car on the open road.

Explaining the Size of Sauropods

[This excerpt is from chapter 3 of The Rise and Fall of the Dinosaurs, written by Steve Brusatte in 2018.]

      Our computer modeling study and more traditional studies based on limb-bone measurements come to the same conclusion: sauropod dinosaurs were really, really big. The primitive proto-sauropods like Plateosaurus began to experiment with relatively large sizes in the Triassic, as some of them got up to about two or three tons in weight. That's roughly equivalent to a giraffe or two. But after Pangea started to split, the volcanoes erupted, and the Triassic turned into the Jurassic, the true sauropods got much larger. The ones that left tracks in the Scottish lagoon weighed about ten to twenty tons, and later in the Jurassic, famous beasties like Brontosaurus and Brachiosaurus expanded to more than thirty tons. But that was nothing compared to some supersize Cretaceous species like Dreadnoughtus, Patagotitan, Argentinosaurus—members of an aptly named subgroup called the titanosaurs—which weighed in excess of fifty tons, more than a Boeing 737.

      The biggest and heaviest land animals today are elephants. Their sizes vary, depending on where they live and which species they belong to, but most weigh about five or six tons. Apparently the largest one ever recorded was around eleven tons. They have nothing on sauropods. Which circles back to the money question: how were these dinosaurs able to attain sizes so completely out of scale with anything else evolution has ever produced?

      The first thing to consider is what animals require to become really big. Perhaps most obvious, they need to eat a lot of food. Based on their sizes and the nutritional quality of the most common Jurassic foodstuffs, it's estimated that a big sauropod like Brontosaurus probably needed to eat around a hundred pounds of leaves, stems, and twigs every day, maybe more. So they needed a way to gather and digest such vast quantities of grub. Secondly, they need to grow fast. Growing bit by bit, year by year is all well and good, but if it takes you over a century to get big, that's many opportunities for a predator to eat you, or a tree to fall on you during a storm, or a disease to take you out long before you grow into your full-size adult body. Third, they must be able to breathe very efficiently, so they can take in enough oxygen to power all of the metabolic reactions in their immense bodies. Fourth, they need to be constructed in a way that their skeleton is strong and sturdy, but also not so bulky that it can’t move. Finally, they need to shed excess body heat, because in hot weather it is very easy for a big creature to overheat and die.

      Sauropods must have been able to do all of these things. But how? Many scientists who started to ponder this riddle decades ago went for the easiest answer: maybe there was something different in the physical environment back in the Triassic, Jurassic, and Cretaceous. Perhaps gravity was weaker, so heftier animals could move and grow more easily back then. Or maybe there was more oxygen in the atmosphere, so the hulking sauropods could breathe, and therefore grow and metabolize, more efficiently. These speculations might sound convincing, but on closer scrutiny they don’t check out. There is no evidence gravity was substantially different during the Age of Dinosaurs, and oxygen levels back then were about the same as today, or maybe even slightly lower.

      That leaves only one plausible explanation: there was something intrinsic about sauropods that allowed them to break the shackles that constrained all other land animals—mammals, reptiles, amphibians, even other dinosaurs—to much smaller sizes. The key seems to be their unique body plan, which is a mixture of features that evolved piecemeal during the Triassic and earliest Jurassic, culminating in an animal perfectly adapted for thriving at large size.

      It all starts, with the neck. The long, spindly, slinky-shaped neck is probably the single most distinctive feature of sauropods. A longer-than-normal neck started to evolve in the very oldest Triassic proto-sauropods, and it got proportionally longer over time, as sauropods both added more vertebrae—the individual bones in the neck—and stretched each individual vertebra ever further. Like Iron Man’s armor, the long necks conferred a kind of superpower: they allowed sauropods to reach higher in the trees than other plant-eating animals, giving them access to a whole new source of food. They could also park themselves in one area for several hours and extend their necks up and down and all around like a cherry picker, gobbling up plants while expending very little energy. That meant they were able to eat more food, and thus take in energy more efficiently, than their competitors. That’s adaptive advantage number one: their necks permitted them to eat the huge meals necessary to put on excessive weight.

      Then there’s the way that they grew. Recall that the dinosauromorph ancestors of dinosaurs developed higher metabolisms, faster growth rates, and a more active lifestyle than many of the amphibians and reptiles that were also diversifying in the earliest Triassic. They weren't lethargic, and it didn’t take them aeons to grow into adults like an iguana or a crocodile. This was also true of all of their dinosaur descendants. Studies of bone growth indicate that most sauropods matured from guinea-pig-size hatchlings to airplane-size adults in only about thirty or forty years, an incredibly short period of time for such a remarkable metamorphosis. That’s advantage two: sauropods obtained the fast growth essential to reach large size from their distant, cat-size ancestors.

      Sauropods also retained something else from their Triassic ancestors: a highly efficient lung. The lungs of sauropods were very similar to those of birds and very different from ours. While mammals have a simple lung that breathes in oxygen and exhales carbon dioxide in a cycle, birds have what is called a unidirectional lung: air flows across it in one direction only, and oxygen is extracted during both inhalation and exhalation. The bird-style lung is extra efficient, sucking up oxygen with each breath in and each exhalation. It's an astounding feature of biological engineering, made possible by a series of balloonlike air sacs connected to the lung, which store some of the oxygen-rich air taken in during inhalation, so that it can be passed across the lung during exhalation. Don’t worry if it sounds confusing: it is such a strange lung that it took biologists many decades to figure out how it works.

      We know that sauropods had such a birdlike lung because many bones of the chest cavity have big openings, called pneumatic fenestrae, where the air sacs extended deep inside. They are exactly the same structures in modern birds, and they can only be made by air sacs. So that’s adaptation three: sauropods had ultra-efficient lungs that could take in enough oxygen to stoke their metabolism at huge size. Theropod dinosaurs had the same bird-style lungs, which could have been one factor that allowed tyrannosaurs and other giant hunters to get so large, but the ornithischian dinosaurs did not. This is why duck-billed dinosaurs, stegosaurs, horned species, and armored dinosaurs were never able to grow as huge as sauropods.

      It turns out that air sacs also have another function. Aside from storing air in the breathing cycle, they also lighten the skeleton when they invade bone. In effect, they hollow out the bone, so that it still has a strong outer shell but is much more light-weight, the way an air-filled basketball is lighter than a rock of similar size. Want to know how sauropods could hold up their long necks without toppling over like an unbalanced seesaw? It’s because all of the vertebrae were so engulfed by air sacs that they were little more than honeycombs, featherweight but still strong. And that's advantage four: the air sacs allowed sauropods to have a skeleton that was both sturdy and light enough to move around. Without air sacs, mammals, lizards, and ornithischian dinosaurs had no such luck.

      And what about the fifth special adaptation, being able to expel excess body heat? The lungs and air sacs helped with this too. There were so many air sacs, and they extended throughout so much of the body, snaking their way into bones and between internal organs, that they provided a large surface area for dissipating heat. Each hot breath would be cooled by this central air conditioning system.

      Putting it all together, that’s how you can build a supergiant dinosaur. If sauropods had lacked any one of these features—the long neck, the fast growth rates, the efficient lung, the system of skeleton-lightening and body-cooling air sacs—then they probably would not have been capable of becoming such behemoths. It wouldn’t have been biologically possible. But evolution assembled all of the pieces, put them together in the right order, and when the kit was finally assembled in the post-volcanic world of the Jurassic, sauropods suddenly found themselves able to do something no other animals, before or since, have been able to do. They became biblically huge and swept around the world; they became dominant in the most magnificent way—and they would remain so for another hundred million years.

The Size of Sauropods

[This excerpt is from chapter 3 of The Rise and Fall of the Dinosaurs, written by Steve Brusatte in 2018.]

      This raises a question that has fascinated paleontologists for over a century: how did sauropods become so large?

      It’s one of the great puzzles of paleontology. But before trying to solve it, we first need to come to grips with a more fundamental issue: how big did sauropods get? How long were they, how high could they stretch their necks, and most important, how much did they weigh? These turn out to be difficult questions to answer, particularly when it comes to weight, because you can't just stick a dinosaur on a scale and weigh it. A trade secret among paleontologists is that many of the fantastical numbers you see in books and museum exhibits—Brontosaurus weighed a hundred tons and was bigger than a plane!—are pretty much just made up. Educated guesses or, in some cases, barely that. Recently, however, paleontologists have come up with two different approaches to more accurately predict the weight of a dinosaur based on its fossil bones.

      The first is really quite simple arid relies on basic physics: heavier animals require stronger limb bones to support their weight. This logical principle is reflected in how animals are built. Scientists have measured the limb bones of many living animals, and it turns out that the thickness of the main bone in each limb that supports the animal—the femur (thighbone) for those that walk on two legs only or the femur plus the humerus (upper arm bone) for those that stand on all fours—is strongly statistically correlated with the weight of the animal. In other words, there is a basic equation that works for almost all living animals: if you can measure limb-bone thickness, you can then calculate body weight with a small but recognized margin of error—simple algebra you can do with a basic calculator.

      The second method is more intensive but a lot more interesting. Scientists are starting to build three-dimensional digital models of dinosaur skeletons, add on the skin and muscles and internal organs in animation software, and use computer programs to calculate body weight….

The End of the Triassic Period

[This excerpt is from chapter 3 of The Rise and Fall of the Dinosaurs, written by Steve Brusatte in 2018.]

      …And then, when Pangea had been stretched to its limit, the crust burst and volcanoes started to erupt, burying the basins and the creatures that lived within them.

      The first eruptions didn't occur in the Newark Basin area. They happened in what is now Morocco, which at that time was nudged up against what would become eastern North America, just a few hundred miles or so from modern New York City. Then lava began pouring out in other places where Pangea was splitting: in the Newark Basin, in what is now Brazil, in those same lake environments where we found the supersalamander graveyard in Portugal—all along that zipper line, which, many millions of years later, would transform into the Atlantic Ocean. The lava came in four waves, each scorching the once verdant rift basins, each spreading toxic fumes all over the planet, each making a bad situation worse and worse. In only about half a million years—a blink of an eye in geological terms— the eruptions stopped, but they transformed the Earth forever.

      The dinosaurs, pseudosuchian crocodile-line archosaurs, big amphibians, and early mammal relatives living in the rift basins were blissfully unaware of what was about to happen. Things went sour quickly.

      The initial eruptions in Morocco released clouds of carbon dioxide, a powerful greenhouse gas, which rapidly warmed the planet. It got so hot that strange ice formations buried within the seafloor, called clathrates, melted in unison all throughout the world’s oceans. Clathrates are unlike the solid blocks of ice we're used to, the ones we put in our drinks or carve into fancy sculptures at parties. They are a more porous substance, a latticework of frozen water molecules that can trap other substances inside it. One of those substances is methane, a gas that seeps up constantly from the deep Earth and infiltrates the oceans but is caged in the clathrates before it can leak into the atmosphere. Methane is nasty: it’s an even more powerful greenhouse gas than carbon dioxide, packing an earth-warming punch over thirty-five times as great. So when that first torrent of volcanic carbon dioxide increased global temperatures and melted the clathrates, all of that once-trapped methane was suddenly released. This initiated a runaway train of global warming. The amount of greenhouse gas in the atmosphere approximately tripled within a few tens of thousands of years, and temperatures increased by 3 or 4 degrees Celsius.

      Ecosystems on land and in the oceans couldn’t cope with such rapid change. The much hotter temperatures made it impossible for many plants to grow, and indeed upwards of 95 percent of them went extinct. Animals that fed on the plants found themselves without food, and many reptiles, amphibians, and early mammal relatives died out, like dominoes falling up the food chain. Chemical chain reactions made the ocean more acidic, decimating the shelly organisms and collapsing food webs. Climate became dangerously variable, with episodes of intense heat followed by cooler periods. This enhanced the temperature differences between northern and southern Pangea, causing the megamonsoons to become more severe, the coastal regions to become even wetter, and the continental interiors to grow much drier. Pangea had never been a particularly hospitable place, but those early dinosaurs that already were constrained by the monsoons, the deserts, and their pseudosuchian rivals were now in even worse shape.

The End of the Permian Period

[This excerpt is from chapter 1 of The Rise and Fall of the Dinosaurs, written by Steve Brusatte in 2018.]

      Imagine a continent scorched with lava. It’s the apocalyptic disaster of a bad B movie. Suffice it to say, all of the pareiasaurs, dicynodonts, and gorgonopsians living anywhere near the Siberian area code were finished. But it was worse than that. When volcanoes erupt, they don’t expel only lava, but also heat, dust, and noxious gases. Unlike lava, these can affect the entire planet. At the end of the Permian, these were the real agents of doom, and they started a cascade of destruction that would last for millions of years and irrevocably change the world in the process.

      Dust shot into the atmosphere, contaminating the high-altitude air currents and spreading around the world, blocking out the sun and preventing plants from photosynthesizing. The once lush conifer forests died out; then the pareiasaurs and dicynodonts had no plants to eat, and then the gorgonopsians had no meat. Food chains started to collapse. Some of the dust fell back through the atmosphere and combined with water droplets to form acid rain, which exacerbated the worsening situation on the ground. As more plants died, the landscape became barren and unstable, leading to massive erosion as mudslides wiped out entire tracts of rotting forest. This is why the fine mudstones in the Zachelmie quarry, a rock type indicative of calm and peaceful environments, suddenly gave way to the coarser boulder-strewn rocks so characteristic of fast-moving currents and corrosive storms. Wildfires raged across the scarred land, making it even more difficult for plants and animals to survive.

      But those were just the short-term effects, the things that happened within the days, weeks, and months after a particularly large burst of lava spilled through the Siberian fissures. The longer-term effects were even more deadly. Stifling clouds of carbon dioxide were released with the lava. As we know all too well today, carbon dioxide is a potent greenhouse gas, which absorbs radiation in the atmosphere and beams it back down to the surface, warming up the Earth. The CO2 spewed out by the Siberian eruptions didn’t raise the thermostat by just a few degrees; it caused a runaway greenhouse effect that boiled the planet. But there were other consequences as well. Although a lot of the carbon dioxide went into the atmosphere, much of it also dissolved into the ocean. This causes a chain of chemical reactions that makes the ocean water more acidic, a bad thing, particularly for those sea creatures with easily dissolvable shells. It’s why we don’t bathe in vinegar. This chain reaction also draws much of the oxygen out of the oceans, another serious problem for anything living in or around water.

      Descriptions of the doom and gloom could go on for pages, but the point is, the end of the Permian was a very bad time to be alive. It was the biggest episode of mass death in the history of our planet. Somewhere around 90 percent of all species disappeared. Paleontologists have a special term for an event like this, when huge numbers of plants and animals die out all around the world in a short time: a mass extinction. There have been five particularly severe mass extinctions over the past 500 million years. The one 66 million years ago at the end of the Cretaceous period, which wiped out the dinosaurs, is surely the most famous. We’ll get to that one later. As horrible as the end-Cretaceous extinction was, it had nothing on the one at the end of the Permian. That moment of time 252 million years ago, chronicled in the swift change from mudstone to pebbly rock in the Polish quarry, was the closest that life ever came to being completely obliterated.

      Then things got better. They always do. Life is resilient, and some species are always able to make it through even the worst catastrophes. The volcanoes erupted for a few million years, and then they stopped as the hot spot lost steam. No longer blighted by lava, dust, and carbon dioxide, ecosystems were gradually able to stabilize. Plants began to grow again, and they diversified. They provided new food for herbivores, which provided meat for carnivores. Food webs reestablished themselves. It took at least five million years for this recovery to unfold, and when it did, things were better but now very different. The previously dominant gorgonopsians, pareiasaurs, and their kin were never to stalk the lakesides of Poland or anywhere else while the plucky survivors had the whole Earth to themselves. A largely empty world, an uncolonized frontier. The Permian had transitioned into the next interval of geological time, the Triassic, and things would never be the same. Dinosaurs were about to make their entrance.

Learning to Teach

[These excerpts are from an article by Firdous A. Khan in the 20 December 2019 issue of Science.]

      While preparing to teach my first lecture as a new faculty member, I told myself: “You have many research presentations under your belt; you’ll nail this!” It didn’t take long for me to realize that I was way off base. A few minutes in, the students looked tired, distracted, and in no mood to listen—a stark contrast to my research talk audiences, which seemed attentive at least….

      I started to reflect on my own experiences as a student and tried to recall the things that helped me learn, as well as the things that didn’t. The researcher in me also began to search for scientific evidence to guide me. I sought help from experts in pedagogy, as well as colleagues who had more teaching experience than I did. They told me about tools that they used during lectures and resources on campus for new teachers.

      Within 1 year, there was a marked change in my teaching. I began to use new skills and tools that kept my students engaged. One student wrote in a teaching evaluation that my approach to teaching “made the information exciting” and “challenged students to pay attention.” Teaching gradually became a source of satisfaction rather than anxiety.

      Here are some of the lessons that have helped me become a more effective teacher.

      SEEK HELP. Teaching is a skill and as such needs to be learned. Many scientists assume that their graduate degree or post-doctoral experience qualifies them to be a teacher. The reality is far from that….

      KEEP IT INTERACTIVE. Actively engaging students is essential for holding their attention and nurturing critical thought….

      BE COMPASSIONATE. Students are more likely to learn if they feel the teacher genuinely cares about them and respects them. So treat every student with understanding and compassion, and make it clear to them that they can come to you for help. It is also important to be mindful of the diversity in student backgrounds and approaches to learning….

      Teaching isn’t always easy or intuitive, but it’s your responsibility to help your students learn. Put in the time to create an environment that maximizes learning for everyone.

A ‘Missing Link’ Microbe Emerges

[These excerpts are from an article by Elizabeth Pennisi in the 20 December 2019 issue of Science.]

      This year, microbiologists took a major step toward resolving a controversy over the origin of eukaryotes, the group that encompasses all plants and animals—including humans. After 12 years of trying, a team in Japan succeeded in growing a mysterious microbe from deep-sea sediments and sequenced its genome. It could shed light on the ultimate ancestry of us all.

      The organism, Prometheoarchaeum syntrophicum strain MK-D1, is a member of the recently recognized Asgard group of microbes, which are not bacteria but a completely separate branch of life called archaea. The Asgards were known only from DNA fragments isolated from deep-sea sediments and other extreme environments. Surprisingly, those fragments contain genes formerly thought to be found only in eukaryotes—organisms with cells that have nuclei and organelles such as mitochondria. Comparative DNA analyses indicated the Asgards, or an ancient relative, may have even given rise to eukaryotes. That radical idea would shrink the domains of life from three—archaea, eukaryotes, and bacteria—to two: bacteria and archaea, with eukaryotes reduced to a subset of archaea. But given the scant evidence, many researchers were skeptical.

      By growing an Asgard in culture, the team in Japan could sequence its full genome and confirm that it carries eukaryotic genes. The researchers also found that it seems to grow best in association with certain bacteria, and that it forms short tentacles that might engulf bacterial companions. If so, that could explain how an Asgard acquired the microbial guests that became mitochondria….

      Other studies this year have identified more eukaryotic genes in DNA fragments from other members of the Asgard group. And information derived from DNA about Asgard metabolism also bolsters the two-domain over the three-domain hypothesis. Proponents of both ideas agree, however, that events that happened almost 3 billion years ago will be hard to reconstruct, and that new ideas may emerge as more Asgards are studied—and, perhaps, cultured. But with one now in hand, researchers have a clearer window into that distant past.

Face to Face with the Denisovans

[This article by Elizabeth Culotta is in the 20 December 2019 issue of Science.]

      Almost 40 years ago, a Buddhist monk found an odd human jaw bone in Baishiya Karst Cave, high on the edge of the Tibetan Plateau. Recognizing that the jaw, with its giant molars, was something special, he gave it to another monk, who donated it to scholars. But no one knew what to make of it. Then in May, scientists applied a new method of analyzing ancient proteins and identified the strange jaw as that of a Denisovan, a mysterious human ancestor who ranged across Asia until some 50,000 years ago, about the same time as the Neanderthals. The work brings these enigmatic ancient people into focus, and heralds a potential protein-based revolution in understanding ancient life.

      The Denisovans have haunted human evolution researchers for 10 years. Back in 2010, researchers identified them by sequencing DNA from a fossilized pinkie bone found in Denisova Cave in Siberia. The DNA, which came from a girl, differed from that of Neanderthals and modern humans. Today, ghostly traces of Denisovans linger in the DNA of living people across Asia, suggesting the group was once widespread and mingled with both Neanderthals and modern humans. But until this year, only a few scraps of additional Denisovan fossils had been identified, all from Denisova Cave. Scientists were left guessing what the Denisovans looked like.

      The 160,000-year-old Baishiya jaw yielded no DNA. But a Chinese and European team managed to extract collagen, a common protein, from the bone, and match it with collagen from the Denisova Cave girl. That suggested the jaw was Denisovan and that these mystery humans had robust jaws, big molars, and teeth with three roots.

      In September, another team refined that picture by applying a new technique to the Denisova Cave girl’s genome. They traced chemical modifications of the DNA called methylation, which can silence genes, then combined that information with a data-base that describes how missing or defective genes influence anatomy in living people. The results suggested how the methylation pattern of the girl's DNA might have shaped her body. The team concluded that she would have looked a lot like a Neander-thal, with a wide pelvis, sloping forehead, and protruding lower jaw. But she also had a wider face than modern humans or Neanderthals, and a longer arch of teeth along her jaw bone. When the researchers tested their view of the Denisovan smile against the newly identified Baishiya jaw bone, it fit almost perfectly.

The Rhetorical Secretary

[These excerpts are from an article by Mark Hlavacik in the December 2019/January 2020 issue of Phi Delta Kappan.]

      …Founded in 1979, the Department of Education was meant to institutionalize the government’s role in leading civic discussion about education. As he signed the legislation creating the new federal agency, Jimmy Carter explained that he considered its rhetorical mission the equal of its regulatory mission:

        I came to the office of the Presidency determined that the American people should receive a better return on their investment in education. I came equally determined that our Nation’s formidable educational challenges should be brought to the forefront of national discussion where they belong.

      For Carter, the secretary of education would be integral to the success of the new department because the secretary would be the driving force behind its rhetorical leadership. “For the first time,” he declared, “there will be a Cabinet-level leader in education, someone with the status and the resources to stir national discussion of critical educational concerns.” By “stimulating needed debate of educational issues,” the secretary was to be, in effect, a national storyteller for the schools.

      Forty years later, it is safe to say that Carter’s vision has been fulfilled. The secretaries of education — 13 of them to date — have been integral to every major civic discussion of education from the 1980s to the present. Indeed, it has become difficult to imagine what a national discussion of education policy would sound like without their leadership.

      And yet, that is exactly what Secretary Betsy DeVos has challenged us to do. Portraying the very existence of the Department of Education as a “giant nod to union bosses,” DeVos counts its creation among a series of failed reforms. To correct this misstep, she urges her fellow Americans to cut government out of the loop, insisting that “federal mandates distort what education ought to be: a trusting relationship between teacher, parent, and student.”

      …Just as Carter hoped, education has become a national political issue, featuring arguments over accountability, choice, and equity that rely on comparisons between schools that are most meaningful when made at scale….So, although Carter declared the regulatory and rhetorical functions of the Department of Education equal, the reality is that most secretaries of education have relied on the bully pulpit as their main source of influence….

      Whenever the secretary points to a specific student, teacher, administrator, school, district, or state, and whenever she releases a report or changes a policy, the content of the story she tells is met with scrutiny, discussion, and further research, as it should be. In this way, secretaries of education are held accountable by journalists, academics, teachers, and the public for the veracity, consistency, and fairness of what they say….

      However, among those who’ve had the most lasting impact on the politics of education, we can make one generalization: While they've differed widely in their policy preferences, they’ve shared a basic commitment to encouraging the American people to take collective responsibility for the nation’s educational future….

Planning for a Warmer World

[These excerpts are from an article by Daniel A. Reifsnyder in the 13 December 2019 issue of Science.]

      …the authors point to “no more” moments that can bring about large-scale, decisive action, but they acknowledge that “the rest of the time we largely fail to learn from our experience.” Take, for example, their stunning observation that 8 of the 18 most hurricane-prone states in the union have no mandatory, statewide building code.

      Why does this happen? In their view, the reasons are many and include prohibitive construction costs, the potential for lost tax revenue, a fear of litigation, optimism bias (our tendency to believe that situations will resolve favorably), and inertia.

      …human biases that I make us reluctant to act. Here, they describe the staggering costs borne by the federal government for disaster relief ($130 billion between 2005 and 2008, for example, spent mostly in response to Hurricanes Katrina, Rita, and Wilma). The authors cite former l'reasury Secretary Henry Paulson’s argument that if Republicans really care about limited government, they should care about controlling climate change before it results in never-ending climate bailouts.

      …For years, the issue of displacement and relocation was something of a taboo subject in international climate debates, both because it is so sensitive and because solutions are not readily apparent….

      …even the Obama White House dropped “managed retreat” for more politically palatable alternatives. “Our political leaders will need to begin a national conversation on this sensitive topic, and the sooner the better….The earlier we start, the easier, and less costly, and less traumatic building resilience will be….”

DNA from Arctic Lakes Traces Past Climate Impacts

[These excerpts are from an article by Paul Voosen in the 13 December 2019 issue of Science.]

      High in the Canadian Arctic on Baffin Island, beneath 10 meters of water and many more of mud, sits a refrigerated archive of Earth’s past life. The deep sediments in a small lake called CF8 hold ancient pollen and plant fossils. But it now appears that the mud harbors something else: ancient DNA from as far back as the Eemian, a period 125,000 years ago when the Arctic was warmer than today, left by vegetation that otherwise would have vanished without a trace….

      Lately, Arctic lakes have emerged as the premier archive for sedimentary ancient DNA, because they collect clues to entire ecosystems. Leaves, flowers, dung—some part of every organism that lives around a lake ends up in the water….DNA is sprung from its cells by decay, then attaches to mineral grains or organic compounds, which provide protection from ultraviolet radiation and oxidation. Temperatures at the lake bottom hover just above freezing, keeping the DNA stable. And year after year, the sediment keeps accumulating, its layers allowing clear dating of the DNA’s deposition.

      Traditionally scientists have used pollen grains from lakebed cores to study past plant communities. But most plants in the Arctic are pollinated by insects, not by wind, so that little pollen ends up in the soil—and what’s there could have blown in from a distance. DNA in lake sediments more accurately reflects the plants and wildlife found nearby….

      It’s not easy to extract the DNA. Scientists must be careful to collect a sample—typically 1 gram of mud—without contaminating it with modern DNA. Then, in a clean lab, the DNA must be extracted in a painstaking process of trial and error….Organic-rich soils seem to be particularly problematic; they are ripe with molecules like humic acid, which behaves like DNA and can foul later 14equencing efforts….

      Early results challenge the simple notion that climate change triggers a wholesale turnover of plant species….certain larch species did not shift northward as the planet warmed after the last ice age, despite preferring a colder climate. Instead …warming allowed the forest to grow denser, which favored a cold-loving larch….The DNA suggests taller plants invaded as the region warmed: first shrubs, then trees. But Arctic flowers persisted, perhaps by retreating uphill.

      Future climate warming, however, may dislodge—or extirpate—these holdouts. For clues to the fate of ecosystems in an even warmer world, researchers want to find other ancient DNA records that stretch back to the Eemian….

      And as the lakes yield even older records, the field is inching toward studying not only the changes in plant diversity and abundance, but also how individual species adapted to climate change….

Donkeys Face Worldwide Existential Threat

[These excerpts are from an article by Crista Leste-Lasserre in the 13 December 2019 issue of Science.]

      …Over the past 6 years, Chinese traders have been buying the hides of millions of butchered donkeys (Equus asinus) from develop-ing countries and shipping them to China, where they’re used to manufacture ejiao, a traditional Chinese medicine. The trade has led to an animal welfare nightmare, along with a threat to donkey populations, the severity of which is only now emerging. Without drastic measures, the number of donkeys worldwide will drop by half within 5 years….The crisis threatens many of the world's rarer donkey breeds and a vital means of transport for the poor. But it is also spurring new studies of donkey biology—including how to speed their reproduction.

      Ejiao, in use for thousands of years, purportedly treats or prevents many problems, including miscarriage, circulatory issues, and premature aging, although no rigorous clinical trials support those claims. The preparation combines mineral-rich water from China’s Shandong province and collagen extracted from donkey hides, traditionally produced by boiling the skins in a 99-step process. Once reserved for China’s elites, ejiao is now marketed to the country’s booming middle class, causing demand to surge….

      Despite government incentives for new donkey farmers, farms in China can’t keep up with the exploding demand, which the Donkey Sanctuary currently estimates at 4.8 million hides per year. Donkeys’ gestation period is one full year, and they only reach their adult size after 2 years. So the industry has embarked on a frenzied hunt for donkeys elsewhere. This has triggered steep population declines. In Brazil, the population dropped by 28% between 2007 and 2017, according to the new report….

What’s the Deal with Rich Men and Space?

[These excerpts are from an article by Zeynep Tufekci in the December 2019 issue of Scientific American.]

      …what’s wrong with dreaming, right? In one sense, nothing. But in another, it matters how people with a lot of money dream. Bezos, Allen and Musk all have talked about their love of science fiction as part of their inspiration for investing in space. Bezos spent his summers reading authors such as Isaac Asimov and Robert A. Heinlein….

      As a former science-fiction geek myself, I can only sympathize. At its best, though, science fiction is a brilliant vehicle for exploring not the far future or the scientifically implausible but the interactions among science, technology and society. The what-if scenarios it poses can allow us to understand our own societies better, and sometimes that's best done by dispensing with scientific plausibility. For example, Ursula K. Le Guin’s brilliant book The Left Hand of Darkness imagines an envoy from Terra (our Earth) to Gethen, a planet without fixed boundaries between genders. Through the hero's encounter with an “ambisexual” species, we end up interrogating our own cultural norms around masculinity and femininity—groundbreaking for a book published in 1969.

      Science fiction is sometimes denigrated as escapist literature, but the best examples of it are exactly the opposite. For me, it’s not the scientifically implausible part of science fiction that is most interesting. It's what the expanded imagination allows us to discover about ourselves and our societies—and then to make them better.

      Science and art have always been somewhat funded through the eccentric interests of the wealthy, and the combination has always been a mixed bag. One thing about being a billionaire is that it’s probably not hard to find people who will encourage you to spend money chasing space operas that either will not happen because of scientific constraints or will end up in disaster.

      But more important, tech billionaires can shape our lives today, through how their companies operate, by repaying their obligations to society through taxes on their enormous wealth (at the moment, fairly little), and through their investments in solving the problems that threaten us. Doing that requires imagination. It’s just not the kind depicted on the covers of science-fiction books I, too, read as a child; it's the kind that takes us to expanded universes only to have us think harder about how to understand the one inhabitable place for us in this vast universe—our fragile, pale blue dot—and make it a better place to live.

Utility-Scale Storage of Renewable Energy

[These excerpts are from an article by Andrea Thompson in the December 2019 issue of Scientific American.]

      The way the world gets its electricity is undergoing a rapid transition, driven by both the increased urgency of decarbonizing energy systems and the plummeting costs of wind and solar technology. In the past decade electricity generated by renewables in the U.S. has doubled, primarily from wind and solar installations, according to the Energy Information Administration. In January 2019 the EIA forecast that wind, solar and other nonhydroelectric renewables would be the fastest-growing slice of the electricity portfolio for the next two years. But the intermittent nature of those sources means that electric utilities need a way to keep energy in their back pocket for when the sun is not shining and the winds are calm. That need is increasing interest in energy-storage technology—in particular, lithium-ion batteries, which are finally poised to be more than just a bit player in the grid.

      For decades pumped-storage hydropower, a simple process that features reservoirs at different elevations, has been the dominant large-scale energy-storage method in the U.S. To store energy, water is pumped into the higher reservoir; when that energy is needed, the water is released into the lower reservoir, flowing through a turbine along the way. Pumped-storage hydropower currently accounts for 95 percent of U.S. utility-scale energy storage, according to the Department of Energy. But as efficiency and reliability have improved, and manufacturing costs have tumbled, lithium-ion batteries have surged. They account for more than 80 percent of the U.S.'s utility-scale battery-storage power capacity, which jumped from just a few megawatts a decade ago to 866 mega-watts by February 2019, the EIA says. A March 2019 analysis by Bloomberg New Energy Finance reports that the cost of electricity from such batteries has dropped by 76 percent since 2012, making them close to competitive with the plants, typically powered by natural gas, that are switched on during times of high electricity demand. To date, whereas batteries have largely been used to make brief, quick adjustments to maintain power levels, utilities in several states, including Florida and California, are adding lithium-ion batteries that will be able to last for two to four hours. Earlier energy research firm Wood Mackenzie estimated that the market for energy storage would double from 2018 to 2019 and triple from 2019 to 2020.

      Lithium-ion batteries will likely be the dominant technology for the next five to 10 years, according to experts, and continuing improvements will result in batteries that can store four to eight hours of energy—long enough, for example, to shift solar-generated power to the evening peak in demand.

      But getting to the point where renewables and energy storage can handle the baseline load of electricity generation will take energy storage at longer timescales, which will mean moving beyond lithium-ion batteries. Potential candidates range from other high-tech options, such as flow batteries, which pump liquid electrolytes, and hydrogen fuel cells, to simpler concepts, such as pumped-storage hydropower and what is called gravity storage. Pumped-storage hydropower is cheap once it is installed, but it is expensive to build and can be used only in certain terrain. Similarly simple is the concept of gravity storage, which purports to use spare electricity to raise a heavy block that can later be lowered to drive a turbine to generate electricity….

      The oldest animal remains that almost everyone can agree on are fossils from Newfoundland that date to about 571 million years ago, shortly after the last regional “Snowball Earth” glaciation that encased much of the planet in thick ice. These earliest known representatives of the Ediacaran biota were dominated by soft-bodied creatures up to a meter in height or width. Some took the form of large, featherlike fronds with vertical stalks that rooted them to the seafloor; others sprawled across the ocean bottom, their flat bodies exhibiting a fractal architecture, with branching units that showed the same patterns at all scales. All these body plans maximize surface area, suggesting that these animals absorbed nutrients directly from the surrounding water.

Bioplastics for a Circular Economy

[These excerpts are from an article by Javier Garcia Martinez in the December 2019 issue of Scientific American.]

      Our civilization is built on plastics. In 2014 alone, industry generated 311 million metric tons, an amount expected to triple by 2050, according to the World Economic Forum. Yet less than 15 percent of it gets recycled. Much of the rest is incinerated, sits in landfills or is abandoned in the environment—where, being resistant to microbial digestion, it can persist for hundreds of years. Plastic debris accumulating in the ocean causes all kinds of problems, from killing wildlife when mistakenly ingested to releasing toxic compounds. It can even enter our bodies via contaminated fish.

      Biodegradable plastics can ease these problems, contributing to the goal of a “circular” plastic economy in which plastics derive from and are converted back to biomass. Like standard plastics derived from petrochemicals, biodegradable versions consist of polymers (long-chain molecules) that can be molded while in their fluid state into a variety of forms. The options currently available—mostly made from corn, sugarcane, or waste fats and oils—generally lack the mechanical strength and visual characteristics of the standard kinds, however. Recent breakthroughs in producing plastics from cellulose or lignin (the dry matter in plants) promise to overcome those drawbacks. In an added boon for the environment, cellulose and lignin can be obtained from nonfood plants, such as giant reed, grown on marginal land not suitable for food crops or from waste wood and agricultural by-products that would otherwise serve no function.

      Cellulose, the most abundant organic polymer on earth, is a major component of plant cell walls; lignin fills the spaces in those walls, providing strength and rigidity. To make plastics from those substances, manufacturers must first break them into their building blocks, or monomers. Investigators have recently found ways to do so for both substances. The lignin work is particularly important because lignin’s monomers are composed of aromatic rings—the chemical structures that give some standard plastics their mechanical strength and other desirable features. Lignin does not dissolve in most solvents, but investigators have shown that certain environ-mentally friendly ionic liquids (which are composed largely of ions) can selectively separate it from wood and woody plants. Genetically engineered enzymes similar to those in fungi and bacteria can then break the dissolved lignin into its components….

      Many hurdles must be overcome before the new plastics can be widely used. One is cost. Another is minimizing the amount of land and water used to produce them—even if the lignin comes only from waste, water is needed to convert it into plastic. As with any major challenge, the solutions will require a combination of measures, from regulations to voluntary changes in the ways society uses and disposes of plastics. Still, the emerging methods for producing biodegradable plastic offer a perfect example of how greener solvents and more effective biocatalysts can contribute to generating a circular econmy in a major industry.

Smarter Fertilizers Can Reduce Environmental Contamination

[These excerpts are from an article by Jeff Carbeck in the December 2019 issue of Scientific American.]

      To feed the world's growing population, farmers need to increase crop yields. Applying more fertilizer could help. But standard versions work inefficiently and often harm the environment. Fortunately, products that are more ecologically sound—controlled-release fertilizers—are available and becoming increasingly smart.

      Farmers typically fertilize crops in two ways. They spray fields with ammonia, urea or other substances that generate the nutrient nitrogen when they react with water. And they apply granules of potash or other minerals to produce phosphorus, also in reaction to water. But relatively little of those nutrients makes its way into the plants. Instead much of the nitrogen goes into the atmosphere in greenhouse gases, and phosphorus ends up in watersheds, frequently triggering excessive growth of algae and other organisms. Controlled-release formulations, in contrast, can ensure that significantly higher levels of nutrients reach the crops, leading to higheryields with less fertilizer.

      A class known as slow-release fertilizers has been sold for some time. These formulations typically consist of tiny capsules filled with substances that contain nitrogen, phosphorus and other desired nutrients. The outer shell slows both the rate at which water can access the inner contents to liberate the nutrients and the rate at which the end products escape from the capsule. As a result, nutrients are meted out gradually, instead of in a wasteful, rapid burst that cannot be absorbed efficiently. Newer formulations include substances that slow nutrient delivery still further, by retarding the conversion of starting materials, such as urea, to nutrients.

      Recently fertilizers that more fully fit the description “controlled release” have been developed—made possible by sophisticated materials and manufacturing techniques that can tune the shells so that they alter nutrient-release rates in desired ways as the soil’s temperature, acidity or moisture changes. By combining different types of tuned capsules, manufacturers can make fertilizers that have profiles tailored to the needs of specific crops or growing conditions….

      Although controlled-release technologies make fertilizers more efficient, they do not eliminate all drawbacks of fertilizer use. The products still include ammonia, urea and potash, for example; producing these substances is energy-intensive, which means that their manufacture can contribute to greenhouse gas production and climate change. This effect could be mitigated, however, by using environmentally friendlier sources of nitrogen and incorporating microorganisms that improve the efficiency of nitrogen and phosphorus uptake by plants. There is no evidence that the materials composing the shells hurt the environment, but this risk must be monitored whenever any new substances are introduced in high volumes.

      Controlled-release fertilizers are part of a sustainable approach to agriculture known as precision farming. This approach improves crop yield and minimizes excessive nutrient release by combining data analytics, artificial intelligence and various sensor systems to determine exactly how much fertilizer and water plants need at any given time and by deploying autonomous vehicles to deliver nutrients in prescribed amounts and locations. Installing precision systems is costly, though, so only large-scale operations tend to have them. In comparison, advanced controlled-release fertilizers are relatively inexpensive and could be a front-line technology that would help farmers to sustainably increase crop production.

Teaching the Human Dimensions of Climate Change for 30 Years

[These excerpts are from an article by Pamela Wasserman in the December 2019 issue of Population Connection.]

      There are many excellent teacher resources available to explain climate science, but fewer that address the role that population growth has played in greenhouse gas emissions, or that delve into how vulnerable communities are being impacted by a rapidly changing climate….

      Despite polling that shows 8 in 10 Americans now acknowledge that human activity is fueling climate change, some teachers are still reticent to address the topic, fearing a backlash from parents, especially in politically conservative areas….the emphasis on presenting scientific data and allowing students to draw their own conclusions makes it easier to teach a “controversial” subject….

Climate Change and Contraception

[These excerpts are from an article by John Bongaarts and Regine Sitruk-Ware in the December 2019 issue of Population Connection.]

      Global climate change represents a grave threat to the future of human welfare and our natural environment. The contentious ongoing policy debate about potential interventions focuses on switching to renewable energy sources and increasing energy use efficiency. But given the urgency of the problem and the lack of political will, other approaches to limit greenhouse gas emissions should be given higher priority. Improving access to effective contraception is one such policy that has thus far been largely ignored by the international climate community….

      In 2100, our planet is expected to be home to 10.9 billion people, up from today’s 7.7 billion. This expansion of humanity will take place mostly in sub-Saharan Africa and South Asia. Rapid population growth has pervasive adverse effects on societies, economies, and the natural environment. In particular, with an additional 3 billion people producing greenhouse gases, the global warming problem will become even more intractable in the coming decades.

      …Lack of access to services and the relatively high cost of modern contraceptives are obvious obstacles for poor women, in particular in rural areas of the developing world. Addressing these issues is a key objective of family planning programs which bring services to local communities and provide methods for free or at low cost. However, there are other, often more important, obstacles such as myths about hormones, traditional social norms, and disapproval of husbands. In fact, fear of side effects and dissatisfaction with available methods are often the dominant reasons women are reluctant to use (or continue to use) contraception.

      Social norms dictate how people ought to behave, particularly in traditional societies where patriarchy is dominant; women are expected to follow the decisions of their husbands and community elders. These customs constrain the introduction of new behaviors such as fertility regulation in societies where it has been absent….

Global #ClimateStrike Demands Real Action to Mitigate Climate Crisis

[This excerpt is from an article by Lindsay Apperson in the December 2019 issue of Population Connection.]

      …We’ve already seen the impacts of climate change. Humanity has killed off 60 percent of the global wildlife population since 1970, with human-induced climate change being one of the leading causes. Sea ice in the Arctic has shrunk every decade since 1979. Sea levels are rising, inundating coastal communities, wildfires are ravaging old-growth forests, hurricanes are getting stronger and destroying everything in their paths, and droughts are plaguing farmers and thirsty people around the world.

      Marginalized communities are disproportionately impacted by unfair environmental and climate practices. The Inuit in the Arctic, the Yanomami in the Amazon, the Sioux in Standing Rock, and other indigenous groups across the world are losing their lands and facing negative health implications as a direct result of climate change. In the United States, low-income people and people of color have elevated exposure to pollution from extrac-tive industries (e.g. living near toxic coal plants, causing increased rates of asthma). They are more likely to lack access to clean water (Flint), and they die at higher rates during natural disasters and severe weather events.

      Yet even in the face of the most pressing crisis facing humanity, world leaders are rolling back the few regulations that exist to seriously address climate change. In the United States, Donald Trump reversed environmental regulations, causing a 3.4-percent rise in carbon dioxide (CO2) emissions in 2018—the largest increase since 2010, and the second largest increase since 1996. In Brazil, fires devastated the earth’s largest rainforest—which absorbs nearly one-third of CO2 emissions—largely due to President Jair Bolsonaro's policies that ignored environmental regulations in favor of boosting Brazil's beef industry. Despite demands from climate activists across the world, leaders still have not done enough to address climate change….

Nitrogen Crisis Threatens Dutch Environment—and Economy

[These excerpts are from an article by Erik Stokstad in the 6 December 2019 issue of Science.]

      …They are protesting a Dutch high court decision that in May suspended permits for construction projects that pollute the atmosphere with nitrogen compounds and harm nature reserves. The freeze has stalled the expansion of dairy, pig, and poultry farms—major sources of nitrogen in the form of ammonia from animal waste. Also blocked are plans for new homes, roads, and airport runways, because construction machinery emits nitrogen oxides….

      The government is preparing to enact short-term measures, including lowering a highway speed limit, which could reduce nitrogen emissions a sliver. To make a significant dent, many experts say the country’s farm animal sector—the densest in the world—must shrink and recycle more of its nitrogen. Last month, farmers asked for nearly €3 billion over 5 years to help pay for more environmentally friendly ways to deal with manure. Although agriculture is a large source of nitrogen emissions, other sectors will have to rein in their pollution, too….

      Nitrogen, a key nutrient for plants, is also an insidious pollutant. Fertilizer washing off fields ends up in lakes and coastal areas, causing algal blooms that kill marine life. Airborne nitrogen can also harm ecosystems. One source is nitrogen oxides, mostly from power plants and engine exhaust. In the Netherlands, even more comes from the ammonia vapors from livestock urine and manure. Both kinds of nitrogen react to form aerosols that cause smog, damage foliage, and acidify the soil, hindering roots’ absorption of nutrients. (Dutch farmers must add lime to their fields to fight acidity.)

      The Netherlands is a nitrogen hot spot partly because it is a dense, urbanized nation, although controls on power plants and catalytic converters in autos have helped curb nitrogen oxide emissions. The bigger problem is ammonia emissions from concentrated livestock operations….Dutch agriculture is responsible for nearly half of nitrogen pollution that falls in the country….

      Some scientists and environmental groups say the Netherlands should move to circular agriculture: Farms should only produce as much manure as they can use to fertilize nearby fields; cows should graze rather than be fed nitrogen-rich, imported soy; and pigs and poultry should eat food waste. That would mean 50% fewer animals….

The Pursuit of Earth’s Waters

[These excerpts are from an article by Lydia Barnett in the 29 November 2019 issue of Science.]

      How did climatology become climate science? More fundamentally, how did the idea of Earth as an interconnected natural system—one of the conceptual foundations of climate science—emerge from a welter of different disciplines? In clear and engaging prose, historian Sarah Dry narrates the life stories of six individuals….

      Waters of the World takes readers from the lab to the study to the field and back again….

      The main thread linking these biographies is, as the book’s title suggests, water. Tvndall’s studies of glaciers and experiments with water vapor led him to develop the theory of greenhouse gases. Walker’s failed attempts to develop a science of monsoon prediction fostered instead a dawning realization that interlocking systems of high and low pressure conspired to produce what he called “world weather.” Simpson’s lifelong pursuit of tropical clouds and storms generated novel understandings of atmospheric circulation on a global scale, just as her contemporary Stommel’s work on the Gulf Stream revealed the interconnectedness of the world's oceans. Dansgaard’s fascination with snow and rainwater led him to engineer the method of ice core sampling that proved foundational to the birth of paleoclimatology.

      Dry shows how disappointments and dead ends, creative workarounds, and the contingencies of funding, training, family relationships, scholarly networks, health and mental illness, and access to instruments, institutions, and other people’s labor all shaped scientific inquiry into the planet's oceans, atmosphere, and ice sheets….

      …Waters of the World is a history that functions as a plea for interdisciplinary work on the problem of climate. The book ends with a call to climate scientists to embrace their interdisciplinary roots and to recognize and celebrate that there are “multiple ways of knowing the planet.”

An Even Bigger Climate Problem

[These excerpts are from an editorial by Carolina Schmidt in the 29 November 2019 issue of Science.]

      Holding a major international summit on climate change against a backdrop of civil discontent like the kind that has rocked Chile might have given the world the impression that issues like clean energy can be addressed without also confronting problems of social justice….

      This year, Chile made bold moves to limit climate change. In September, it launched a broad alliance that encourages nations, regions, cities, businesses, and investors to accelerate measures to reduce greenhouse gas emissions and reduce vulnerability to the effects of climate change. And although Chile contributes a mere 0.25% to global carbon emissions, its proposed nationally determined contribution (NDC)—the reductions in greenhouse gas emissions that are at the heart of the international Paris Agreement to limit global temperature rise—was formulated with Chile’s own national agenda of reaching carbon neutrality by 2050.

      Achieving a net zero carbon footprint will require one of the fastest coal shutdowns of any country because the fuel accounts for about 40% of Chile’s electricity generation. The Mitigation Plan for the Energy Sector is aligned with goals set in Chile’s 2050 energy strategy, which has a renewable energy generation target of at least 60% by 2035. Thanks to an Electromobility Strategy, Chile operates the largest electric urban public bus fleet in Latin America, with plans to achieve 100% electric public transport by 2050. These are examples of necessary short-term actions to limit global temperature increase to 1.5°C. In the meantime, a Climate Change Law proposal is under discussion. It is the first Latin American law that formulated a carbon neutrality goal in conjunction with the scientific community. It also proposes a Scientific Council and a Civil Society Council to expand input into policies and a Regional Committee on Climate Change to develop local climate action plans.

      But dealing with climate change will require not only technical and practical transformations in sectors like energy and transportation, but also social transformations. Climate change amplifies social inequities. Sea level rise, droughts, heat waves, and wildfires, among other hazards, affect food, water, air, land, energy, and other securities. Some groups are affected more than others, depending on where they live and their ability to cope. What is needed are “green transitions” that support people who live in poverty and in indigenous communities with limited resources, as well as those in urban communities struck by higher energy costs and air and water pollution.

      How can climate action advance a more sustainable, fairer, and united Chile? Goals, technologies, and policies surrounding climate must be discussed in the context of their impacts across the income distribution. For example, in Chile’s updated NDC, a new aggressive goal to reduce up to 30% of carbon emissions by 2030 was created to address the huge pollution problem associated with cities mainly in the south. The complete coal phase-out program was agreed upon in a roundtable where the government, private sector, local authorities, and civil representatives discussed a transition process that is sensitive to the health and employment of those affected most. And the inclusion of the water security was given priority to address a 10-year drought that has afflicted 70% of the population.

      …Nations cannot address development and prosperity without addressing climate change, and vice versa….

Sidestepping Politics to Teach Climate

[These excerpts are from an article by Ragupathy Kannan in the 22 November 2019 issue of Science.]

      …I teach climate science in my biology classes because I think it’s important to lay out how the climate is changing before I talk about how those changes may impact plants and animals. Some of my students aren’t science majors, so it may be the only time they hear about climate science in a university lecture.

      Recognizing that science doesn’t exist in a vacuum, I also try to make connections between the topics I’m teaching and the wider world. To do that, I set aside a few minutes at the beginning of lectures to talk about science in the news….

      A turning point came the following semester when I received a message from my dean, who regularly reads student evaluations. He had circled a comment from one of my students, writing, “Be careful here.” After thinking it through more carefully, I came to realize that in a polarized political landscape, talking about politicians and the decisions they make is counterproductive. Students may put their guard up, thinking that I’m partisan, and tune me out when I'm lecturing about other things, such as climate modeling. So, I made a conscious decision to change my approach to teaching the subject.

      As part of my modified strategy, I joined a local bipartisan group that aims to bring people together by emphasizing the potential consequences, rather than causes, of climate change. The group taught me about tactful, nonconfrontational ways to discuss climate science.

      Over the past year, I have experimented with my teaching methods, and I have learned that to open my students' minds to the science, I need to find common ground with them. Now, when I discuss climate science news, I focus on things that all of us care about and choose examples that illustrate how climate change might affect their lives. For instance, this summer Arkansas and neighboring states were devastated by catastrophic flooding. It was a topic that hit close to home for all of us, and it gave me the chance to tell my students that major floods are now happening more often than they did in the past.

      Since I altered my teaching strategy, I’ve noticed a shift in my student evaluations. I still get the occasional comment that I’m a “climate doomsdayer,” but overall the evaluations have been much more positive.

      As teachers, we strive to make connections with our students. I’ve learned that delving into the quagmire of politics hinders those connections. But when I instead highlight the ways in which climate change may affect our shared experience on this planet, it’s easier to communicate and connect with all of my students, regardless of their political affiliation.

After 20 Years, Golden Rice Nears Approval

[These excerpts are from an article by Erik Stokstad in the 22 November 2019 issue of Science.]

      Soon. That has long been scientists’ answer when asked about the approval of golden rice, a genetically modified (GM) crop that could help prevent childhood blindness and deaths in the developing world. Ever since golden rice first made headlines nearly 20 years ago, it has been a flashpoint in debates over GM crops. Advocates touted it as an example of their potential benefit to humanity, while opponents of transgenic crops criticized it as a risky and unnecessary approach to improve health in the developing world.

      Now, Bangladesh appears about to be come the first country to approve golden rice for planting….Still, environmental groups haven’t dropped their opposition….And more research will be needed to show the extent of real-world benefits from golden rice.

      Golden rice was developed in the late 1990s…to combat vitamin A deficiency, the leading cause of childhood blindness. Low levels of vitamin A also contribute to deaths from infectious diseases such as measles. Spinach, sweet potato, and other vegetables supply ample amounts of the vitamin, but in some countries, particularly those where rice is a major part of the diet, vitamin A deficiency is still widespread; in Bangladesh it affects about 21% of children….

      Over the past 2 years, regulators in the United States, Canada, New Zealand, and Australia approved golden rice for consumption. There are no plans to grow the crop in these countries, but approval will prevent problems if golden rice somehow accidentally turns up in food supplies….

The Context of Diversity

[These excerpts are from an editorial by Cato T. Laurencin in the 22 November 2019 issue of Science.]

      The term “diversity,” which came about in connection with the passage of the U.S. Civil Rights Act of 1964, has been expanding to include an ever-growing list of identities—from race, gender, and sexual orientation to physical appearance, belief systems, thought styles, socioeconomic status, and rural/urban geographic location, among others. This is a welcome extension of representation, but this added texture has a downside—it threatens to muddle targets and obscure actions when achieving diversity is the goal. This consequence is particularly serious in the context of addressing equity for specific underrepresented racial and ethnic groups….Forging systemic changes that bring Black diversity at all education and career levels will hopefully bring racial equity to practices in these fields and in doing so, expand the benefits of science, engineering, and medicine to society.

      There are unintended negative consequences of the expanded definition of diversity. With so many groups, success in achieving diversity is increasingly measured in a pick-and-choose manner, where progress is defined through any lens that shows success. Also, with so many groups, diversity is often described through the lens of gender, leaving other groups as seemingly less important, or unimportant. And with so many groups, it has become easier for diversity efforts to disregard the historical and present drivers of discrimination that concepts of diversity began with. In other words, the greater context of inclusion and equity can get lost, making strides to diversify meaningless. The latter point is particularly relevant to Blacks in the United States who have experienced slavery, legally enforced segregation and discrimination, and now battle conscious and unconscious racism, and mass incarceration. Institutionalized racism, past and present, has resulted in the disregard, disrespect, and dismissal of Black people from all walks of life, and this is true in science, engineering, and medicine.

      …For example, the number of Black males entering medical school between 2013 and 2014 in the United States was only 500, a historic low. Black men represented only 37.7% of Blacks entering medical school, which represented only 2.5% of all students entering medical school. This occurred during a historic increase in the number of medical schools in the nation….

      In response to this downward trend of Blacks in science and medicine, a number of individuals, including me, convened a U.S. National Academies workshop in 2017 that focused specifically on the growing absence of Black men in medicine in the United States. The ideas became a blueprint for actions that address not only Black men in medicine, but also the trajectory for Black women, and issues in engineering and science overall.

      Embracing the expanding definition of diversity is easy, but using the word with focus so as not to weaken the paths for achieving diversity will take great attention….

Learning to Love Plastic

[These excerpts are from an article by Wade Roush in the December 2019 issue of Scientific American.]

      “Biodegradable” plastic doesn’t do what you think it does. Your paper or metal straw takes only a tiny sip at the problem of plastic pollution. And your supposedly eco-conscious cloth grocery bag is more damaging to the environment than conventional plastic bags—unless you reuse it literally thousands of times. In other words, many of our ideas about plastic and the environment are confused. And that may be getting in the way of the fight against global warming.

      Take the ruckus over single-use plastic bags and straws….The hullabaloo has spurred restaurateurs to roll out cups and utensils made from biodegradable materials such as polylactic acid (PLA), a polyester derived from starchy plants, including corn and sugarcane. The popular myth is that you can safely toss such items onto the forest floor or into the ocean, and microbes will break them down into raw materials that will magically be reborn as daisies or seahorses.

      Not so much. In America and Europe, the technical standards for biodegradability are mostly about industrial composting. Put a plastic bag or bottle into a composting vessel, throw in some microorganisms and turn up the temperature to between 50 and 60 degrees Celsius (122 and 140 degrees Fahrenheit). If 90 percent of the material is released as carbon dioxide within 180 days, then you get to call the item “biodegradable” or “compostable.”

      In other words, a biodegradable material is one deliberately designed to dump its carbon into the atmosphere at the end of its life cycle. Even worse, if biodegradable plastic ends up in an oxygen-deprived landfill rather than a composting facility, anaerobic decomposition will turn it into methane, a gas that warms the planet from 34 to 86 times as much as carbon dioxide. And if you dump biodegradables into the ocean, they break up into tiny bits that choke marine animals long before they degrade appreciably.

      Globally, we produce an eye-popping amount of plastic—some 380 million tons a year, virtually all of it from fossil-fuel feedstocks. So it's understandable why consumers would cling to the comforting 1980s-era idea that plastic can be engineered to disappear back into the environment. But the reality is that 60 percent of all the plastic ever produced is accumulating in landfills or as litter.

      And from a climate scientist’s point of view, that may actually be a good thing. Of course, it’s a crime that so much plastic waste gets into terrestrial and aquatic ecosystems. But we won’t outgrow our need for plastic anytime soon: for one thing, it substitutes for heavier materials in cars and planes, which saves fuel. On top of that—and this is my main point—plastic can function as an artificial carbon sink. If we’re going to extract carbon from the ground at all, far better that it ends up in a soda bottle that will last 400 years than in the combustion chamber of your car.

      If we want to save Earth, we should stop obsessing over biodegradability and invest instead in plastics that are bio-based. Plants use photosynthesis to convert water and CO2 from the atmosphere into sugars, starch and cellulose, all of which can be processed to make plastics. PLA is one of those, but it's designed to be composted, which makes it carbon-neutral at best. The most exciting work in this area focuses on nonbiodegradable plastics such as polyethylene terephthalate (PET), which Coca-Cola uses in its PlantBottle. The current version, introduced in 2009, uses PET that is 30 percent plant-based. Both Coca-Cola and Pepsi have announced bottles made from 100 percent plant-derived PET, although neither has a market-ready version yet.

      The United Nations Intergovernmental Panel on Climate Change points out that to limit global warming to 1.5 degrees C above preindustrial levels, we may need to remove tens to hundreds of gigatons of CO2 from the atmosphere, ideally by 2050. If the world fully converted to nonbiodegradable bioplastics starting in 2020, the carbon sequestered over the next 30 years could amount to more than 10 gigatons—which would be a good start. When it comes to plastic, it's time to think more flexibly.

The Great Molasses Flood

[These excerpts are from an article by Brian Rohrig in the December 2019 issue of ChemMatters.]

      It was a beautiful day in Boston. Even though it was mid-January, the temperature had risen above 4.4 oC (40 oF) by lunchtime, a welcome respite from recent bone-chilling cold. Spirits were high for other reasons, too. World War I had just ended. Bostonians' beloved Red Sox were fresh off a World Series win.

      But on that fateful clay in 1919, the good spirits shattered abruptly when the ground began to shake, and a deafening roar was punctuated by what sounded like machine-gun fire. In short order, anyone within earshot of the blast ran for their lives, if they were able.

      A tank of molasses five stories high had burst, releasing more than 7.6 million liters (2 million gallons) of molasses in a sticky avalanche that enveloped everything in its wake. Buildings crumbled. A fire station near ground zero was destroyed. Steel girders supporting an elevated train bent and twisted. The 1-kilometer (0.62-mile) swath surrounding the tank looked like a war zone.

      At one point, the sticky wave was more than two-stories high, radiating in all directions. It reached a speed of 56 km/h (35 mph), carrying with it shards of jagged metal from the ruptured tank, as well as other debris caught in the flow.

      Unable to outrun the surge of molasses, 21 people died, and more than 100 were injured. Many died from asphyxiation as the thick, sticky fluid filled their lungs. Others were killed by fast-moving debris. Animals also died in the flood—nearly a dozen horses mired in the sweet goo had to be put down, as no amount of effort could free them….

      If you’ve ever tried to pour molasses, you know how slow it is. Molasses is about 5,000 to 10,000 times more viscous than water. Viscosity is defined as resistance to flow—the more viscous the liquid, the slower it flows. Viscosity is highly temperature dependent. A 10 °C drop in temperature can create a threefold increase in viscosity.

      Viscosity comes from the intermolecular forces of attraction acting between adjacent molecules within a substance. Strong intermolecular forces contribute to greater viscosity. If molecules are strongly attracted to one another, they are less likely to flow past each other.

      At colder temperatures, molecules move more slowly and have less energy to overcome intermolecur attractions. This leads to greater viscosity. Think of it this way: Suppose you want to grasp the hands of a person in passing. Running would make this hard to do. But if you are ambling slowly by, it would be easy to join hands, and harder to lose your grip.

      This phenomenon turned a normally useful substance into a deadly one. At first, the distilling company’s molasses flowed out quickly due to warmer temperatures inside the tank, which had been recently filled. But the syrup cooled as it met the wintry air. Its viscosity increased, creating a gooey quagmire.

      The stickiness of the molasses also contributed to the morass. Molasses, being primarily a concentrated sugar solution, clings to just about any surface it encounters. This stickiness is the result of adhesive forces—adhesion is the attraction of unlike surfaces to one another, and is also the result of intermolecular forces. Viscous substances tend to be clingy but not always, since stickiness is dependent on the nature of both surfaces that come into contact. Molasses won’t stick to Teflon, for example.

      Molasses is mostly sugar, and sugar gets sticky when wet. Dry sugar poured from a bag doesn’t stick, but add a little water, and it sticks like glue.

      Sugar molecules’ stickiness is due to polarity. The molecules' protruding hydroxyl groups (-OH) create distinct regions of positive and negative charge. The H side of the -OH group has a partial positive charge, while the O side has a partial negative charge. Sugar readily dissolves in water because the partial positive and negative sides of a polar water molecule will be attracted to the opposite partial charges on a sugar molecule, forming hydrogen bonds.

      When a polar molecule contacts a neutral surface, polarity is induced in the neutral surface as its negative charges are slightly repelled, leaving positive charges at the surface. The negative side of the polar molecule is thus attracted to the now-positive side of the formerly neutral surface.

      To clean up the molasses spill, the affected areas were flushed with salt water from nearby Boston Harbor….

Biome Boost

[These excerpts are from an article by Prachi Patel in the December 2019 issue of Scientific American.]

      Rivers act as Earth’s arteries and veins, providing sustenance and sweeping away waste to keep terrestrial habitats in shape. By that measure, England is unhealthy: a startling 86 percent of its rivers do not meet water-quality standards, posing a risk to wildlife and human health.

      A new study offers hope. Invertebrate biodiversity in one Thames River tributary has increased in the past 30 years, thanks to an adjustment in wastewater treatment….

      Invertebrates such as crustaceans, insects and worms are key players in aquatic ecosystems. They shape their environment by digging into riverbeds and filtering water, and they are both predators and prey. These animals also respond quickly to environmental changes, indicating an ecosystem’s health.

      The researchers analyzed data collected by the U.K. Environment Agency between 1977 and 2017 for a 12-kilometer stretch of the River Ray downstream from a large wastewater treatment plant in the southwestern town of Swindon. They found a steady increase in the variety and numbers of invertebrates since June 1991.

      That timing coincides with the 1991 European Union Urban Wastewater Directive, which pushed treatment plants to switch from filtration to an activated sludge process that uses microbes to break down contaminants. This dramatically cut the organic matter and toxic ammonia going into rivers—and so invertebrate biodiversity slowly improved, the team concluded….

      John Sumpter, an ecotoxicologist at Brunel University London, says this increase most likely boosted diversity among larger creatures, too, and that these results probably apply in other places. Still, published studies showing such improvements are rare….

      …But full restoration will require more work and tougher regulations, he adds, noting the growing problem of agricultural pollution….

Adapt or Mitigate? Both

[These excerpts are from an editorial by the editors in the December 2019 issue of Scientific American.]

      Not that long ago “adaptation” was considered a dirty word among climate activists. Their view was that if we could retool our lives to accommodate the consequences of climate change—rising seas, longer wildfire seasons, and a long list of other not so natural disasters—industries and governments would use that as an excuse to avoid a more important job: curbing our emissions of the heat-trapping greenhouse gases that cause these problems in the first place.

      That position might have been reasonable in 1988, when climatologist James E. Hansen first focused the world’s attention on the threat. Back then there was still time to cut back on emissions in a measured way. More than three decades later, however, we know mitigation didn’t happen. The atmosphere is packed with more carbon dioxide and methane than ever. The most significant reduction effort to date, the much hailed 2015 Paris climate accord, has not yet put a dent in the problem. Climate change is a clearer and more present danger than it has ever been.

      As a result, dismissing adaptation is no longer an option….

      But adapting well takes serious money, and the mechanisms for funding it are misaligned. Many industries and governments, still staving off a systematic overhaul of energy and economic frameworks, are only taking incremental steps to deal with the effects of global warming. One result is that vulnerable communities already experiencing the impact are not receiving adaptation funding from the groups that contributed most to the problem.

      Powerful tools are coming on the scene that could help increase adaptation funding and direct it to those who need it most. Researchers in the emerging field of attribution science, for example, can determine how much climate change is worsening the impact of natural events….

      The focus on mitigation has led to research and debate about the methods, technologies and economics of lowering concentrations of greenhouse gases. But innovations for adaptation tend to be far behind. Ideas for adapting to sea-level rise, for instance, are too focused on “hard” solutions such as seawalls, whereas natural features could be used more widely as protective infrastructure. More cities could be changing their zoning laws to prevent the development of frequently flooded land….

      None of these adaptive actions—which are essential for health, safety and economic stability—diminish the need for a rapid global transition from fossil fuels to clean energy. But they do make climate risk more visible and much harder for politicians and the financial sector to ignore.

What Teachers Know (and Don’t Know) about Learning

[This brief article is in the November 2019 issue of Phi Delta Kappan.]

      A recent survey reveals that teachers’ beliefs about learning do not always match the findings of cognitive scientists. Of the 200 educators surveyed, 97% agreed that people have different learning styles, an idea that has been debunked by scientists. Another myth that teachers endorsed was the idea that people are either right- or left-brained, a belief held by 77% of respondents. Teachers were more skeptical about such myths as the idea that certain kinds of learning are impossible after a certain age, the idea that education cannot help students overcome developmental differences in brain function, and the idea that experience cannot alter a person's mental capacity because it is a genetic trait.

      What about learning strategies that have been endorsed by scientists? A majority of teachers (around 60%) recognized that elaboration (linking new information to old); spacing (spreading out study time, as opposed to cramming the night before), and metacognition (understanding one’s own learning) were effective strategies. However, only 20% of respondents agreed that interleaving (working on a sequence of different types of problems) would be more effective than working on a block of similar problems. Only 31% said that retrieval practice is more effective than rereading, but when presented with a specific classroom scenario, almost 60% preferred the retrieval practice option over rereading.

      According to the report, these findings suggest that findings from cognitive science are not being effectively transmitted to teachers. Because teachers stated on the survey that they get most of their information from professional development courses, conferences, and peers, these avenues are important for sharing the latest science related to learning.

Teacher Stress: Balancing Demands and Resources

[These excerpts are from an article by Christopher Jay McCarthy in the November 2019 issue of Phi Delta Kappan.]

      Teaching is widely recognized to be a stressful occupation, characterized by numerous and varied challenges: administrative burdens, long hours, classroom management difficulties, and lack of autonomy, to name but a few. Teachers are isolated from colleagues for much of the day, spending less than 5% of their work time collaborating with peers….They are also paid less than other workers with similar experience and education, a gap that has grown from 4.3% in 1996 to 17% in 2015, according to the Economic Policy Institute….Further, teachers face significant social and political scrutiny as to how they do their jobs….

      These demands take a toll, resulting in job dissatisfaction, workplace fatigue, burnout, and reduced occupational commitment. The statistics on teacher turnover are grim: Research estimates that between 19°/o and 30% of new teachers leave the field within the first five years of teaching, which can reduce the espirit de corps of their campus community and negatively affect student learning….

      But if it’s clear that teacher stress is widespread, it’s not always clear how teacher stress should be defined. Traditionally, educational policy research has focused on working conditions (i.e., school administration, teacher autonomy, and collegiality with colleagues) as the main driver of occupational health….That is, teacher stress tends to be viewed as a result of working in a stressful environment, often characterized as lacking sufficient funding or effective leadership. However, if only 20-25% of teachers report high levels of stress, then that would suggest that the working environment itself is only part of the issue. In many schools, some teachers are stressed out while others are not; but if working conditions were all that mattered, then every teacher in the school would be equally stressed. Clearly, then, there must be more to the story.

      Chris Kyriacou…and others have argued that teacher stress is better understood as resulting from a mismatch between the pressures and demands made on educators and their ability to cope with those demands. Workforce conditions alone are not sufficient to explain why some teachers are highly stressed. Rather, what matters most is how each teacher sees the demands they face in relation to the resources they have available to meet those demands. Just as beauty is said to be in the eye of the beholder, stress depends on the teacher’s unique view of their classroom. And if this is true, then it should be possible to identify and intervene with teachers who are most vulnerable to stress, above and beyond efforts to improve the larger working environment….

      Of course, on any given day, a teacher might experience some occasions when demands exceed resources and others where the resources meet the demands. Yet, research suggests that it is our overall appraisal that makes the difference: Teachers who chronically find themselves on the losing end of the demand/resource equation are the most vulnerable to stress and most at risk for lowered job satisfaction, greater burnout, and lowered occupational commitment….

How Kappan Authors Have Addressed Stress

[These excerpts are from an article by Teresa Preston in the November 2019 issue of Phi Delta Kappan.]

      Stress and anxiety have no doubt been part of schools since schooling began, but, for decades, they were not frequently addressed….

      In May 1976, Thomas Ringness…took up this idea of anxiety as a fearful anticipatory response to some common event, such as going on stage before an audience, competing in physical education class, taking a test, or visiting the principal’s office. Such fears are common, he argued, and their effects tare not entirely negative….

      …Louis Chandler’s December 1981 article…began with an attempt to help adults understand the child’s perspective when seeking to help them manage stress. Children perceive limits, for example, differently from adults. While adults might chafe against limitations, for children, they create a sense of security and confidence that enables them to seek out new challenges. He also cautioned adults to avoid pushing their own stresses onto children….

      Too often, goals set by outsiders involve factors that are outside students’ (and teachers’) control. And when that happens, said Docterman and Weber, “stress overtakes inspiration. Anxiety replaces optimism….”

      There is no simple way to manage stress in schools, as it arises from so many different sources. But schools can create a climate where mental health is emphasized, and perhaps that will help students and teachers cope….

Everyone’s First Drink

[These excerpts are from an article by Kate Lowenstein and Daniel Gritzer in the September 2019 issue of Reader’s Digest.]

      …The big twist with you humans, of course, is that you figured out how to continue your habit of drinking me well beyond your infancy and into adulthood. And rather than collect human milk and bottle it up, you chose a more efficient lactating creature to supply you: the cow.

      This was an udder stroke of genius. By domesticating a milk-supplying animal—actually, over history, a bunch of them, including sheep, goats, buffalo, camels, and yaks—you found a way to take advantage of otherwise nutritionally useless grasslands and pastures. Ruminants such as cows, sheep, and goats are equipped with multiple stomachs and the (somewhat impolite) habit of regurgitating and re-chewing the contents of those stomachs until they’ve squeezed out every last nourishing molecule. With this unrivaled digestive determination, these beasts manage to turn scraggly weeds into copious amounts of rich and creamy me—and more.

      A milk-producing cow makes on average six or seven gallons of me a day….But studies conducted since the height of fat phobia in the 1990s have suggested that full-fat dairy can be satisfying and decently healthy. Skim milk and low-fat cheese, while lower in calories, just aren’t as satiating.

      The gallon you have of me in your fridge (assuming it’s cow's milk) probably came from an industrial farm, where the cows are often fed grain and corn. Here’s a tip: When you spend a little extra to get a carton marked “from grass-fed cows,” who are out munching their way through pastures, I taste different—some might say better. Further, my flavor will change with the seasons, as the makeup of the grass changes. You might buy the same cheese all year long, but if it’s from pastured cows, its taste and texture will also evolve as spring turns into summer, and so on….

      About 5,000 years ago, a wandering group of you noticed another way I go from perishable liquid to a more long-lasting solid. Shepherds transporting me from field to home would open the bags in which they carried their milk and discover me curdling. There was something about those bags, made from the stomachs of sheep and goats, at work: The stomachs contained an enzyme called rennet, which helps young animals digest their mothers’ milk. Thus began the epic food tradition of making cheese. To this day, rennet from calf stomachs is still used to make many cheeses….

‘Secret Science’ Plan Is Back, and Critics Say It’s Worse

[These excerpts are from an article by David Malikoff in the 15 November 2019 issue of Science.]

      Critics are blasting a revised Trump administration plan to give the U.S. Environmental Protection Agency (EPA) broad power to ignore research results when setting public health rules if officials decide the underlying data are not adequately accessible to the public….

      One issue, critics say, is that EPA wants to greatly broaden the policy's scope, applying it to all studies and data used by the agency and not just the “dose response” studies mentioned in the initial version. The draft also asks the public to comment on whether, in some cases, the transparency rule should be applied retroactively to past studies used to support regulation, potentially opening the door to challenges of existing rules.

      EPA officials have argued that the data transparency policy is needed to ensure that the agency uses only the best “pivotal regulatory science” that can be “independently validated” when crafting “significant” rules that are expected to impose major economic costs. The leaked proposal says EPA regulators should have “the right to place less weight” on certain studies, “to the point of entirely disregarding them,” if the underlying data are “not made available in full to EPA.”

      Critics say that language is primarily designed to weaken regulation by preventing EPA from considering epidemiological and other studies in which researchers have promised to protect the privacy of human subjects. Such confidential health information, which is typically not released to the public, has played a major role in shaping stricter EPA limits on air pollutants. For example, the iconic 1993 Six Cities Study, which linked particulate air pollution to human death and disease, helped spur new EPA soot controls. But some industry groups have long objected to EPA’s use of such “secret science.”

      EPA already has ways to assess the quality of studies and decide which it should consider when writing new rules, notes Chris Frey, a former scientific adviser to the agency and an air quality researcher at North Carolina State University in Raleigh. “But what those methods don’t do is say: ‘Just because there isn’t full public disclosure of the data, we’re going to wipe out and ignore that study, regardless of its quality.’ Doing that would prevent you from considering the full weight of the scientific evidence.”

      The draft acknowledges that full disclosure may not be possible for some studies involving health or proprietary business information; it would empower political appointees at EPA to exempt certain studies from transparency requirements. It also asks for comment on whether EPA should adopt methods, such as those used by the U.S. Centers for Disease Control and Prevention, for only sharing sensitive data with approved researchers.

      But the proposal doesn’t discuss how much such vetting might cost, or how the rule might affect efforts to protect public health….

One Nation under Stress

[These excerpts are from an editorial by Rafael Heller in the November 2019 issue of Phi Delta Kappan.]

      According to Gallup’s…most recent international survey of emotional health, Americans are more frazzled than ever before. On any given day, roughly 55% of us say we feel highly stressed. (Only the citizens of Greece, the Philippines, and Tanzania report higher rates.)

      What’s gotten into us? It's complicated, says the eminent Stanford University biologist Robert Sapolsky, who has spent nearly four decades studying stress, its causes, and its effects. On one hand, stress hormones help humans, like other mammals, respond to immediate physical threats (e.g., hungry lions) and ongoing challenges (e.g., looking for food in the dry season). On the other hand, those hormones also respond to social and psychological conditions. Unlike, say, zebras…, we humans fret about what might happen tomorrow, what happened yesterday, and what didn’t happen at all. We torment ourselves over insults real and perceived. We agonize over threats to our social status. In short, we give ourselves ulcers for a dizzying array of reasons, which have only been amplified by our growing income inequality, declining social cohesion, increasingly sedentary lifestyles, racial tensions, and other political, economic, and societal changes.

      Unfortunately, though, our popular media tend to project a much simpler, one-dimensional version of what stress is and how to cope with it, warns Sapolsky. We Americans tend to think about stress as a personal problem for individuals to “manage” with diet, exercise, yoga, and spa days….

      How, then, should we cope with our stress? That depends, argues Sapolsky, on what’s making us stressed in the first place. (Paying the rent? Impressing our parents? Dealing with climate change?) We shouldn’t expect to find one-size-fits-all solutions, he con-dudes. People need to find the “right strategy for the right time.”

      Today, countless schools across the country are investing in mindfulness programs and wellness rooms. And plenty of research suggests that such programs tend to be helpful. However, by focusing too narrowly on mindfulness and other kinds of stress management, we risk distracting ourselves from the social and institutional forces that are causing so many of us to be so stressed out in the first place.

      …There is much that we can do to make our L schools less stressful places, but first we will need to understand the stressors we face.

Seeking Shared Ground in Space

[These excerpts are from an article by Andrea Ravignani in the 8 November 2019 issue of Science.]

      They shared hits of LSD with dolphins to enhance mutual communication capacities. They suggested that we detonate all existing nuclear bombs on the Moon to create a far-reaching message. They claimed to have received communications from Mars. These individuals, who sound more like characters in a B movie than real people, populate a few of the many fascinating (and true) anecdotes recounted by Daniel Oberhaus in his new book, Extraterrestrial Languages, which chronicles the adventures of scientists who have sought to communicate with extraterrestrial life.

      Oberhaus delivers an engaging read, striking a good balance between “hard” and “popular” science. He reviews centuries of initiatives, combining science with anecdotes, and using linguistics, mathematics, astrophysics, cognition, and art as feedstock. Focusing on practicalities of extraterrestrial communication, he asks: Is it more convenient to send a plaque on a spacecraft or to radio broadcast a mathematical message?

      Presented with these scenarios, the reader realizes a key feature of traditional human communication: It happens in real time. Space messages, on the other hand, might take hundreds of years to reach their intended audience, so they must be self-explanatory.

      A space message should have three features: First, it should be clearly distinguishable from random noise. This could mean sending a signal at specific frequencies and with a character count equaling one prime number times another, so that there is only one possible way to visualize the characters. Second, the message should start by establishing common ground. But choosing universal truths is no obvious task: One overarching question addressed in the book is whether what we call “mathematics,” “language,” and “culture” are absolute or human-relative. Finally, the message should contain information about our planet and us.

      …He defines language as a tool for thinking, not for communicating, borrowing from Noam Chomsky’s theory of generative linguistics. According to this view, humans are the only species with language, a by-product of our language-adapted brains. This all-or-nothing stance sets the bar high, leading him to dismiss, perhaps prematurely, the relevance of animal communication to the discussion….

Laugh Yourself Smarter

[These excerpts are from an article by Adam Piore in the September 2019 issue of Reader’s Digest.]

      …It has been only in the past few years that scanning technologies, such as functional magnetic resonance imaging (fMRI), have let us see how the brain works when it is processing information: which parts do what and what benefits might accrue from exercising different areas. It turns out that joking, long dismissed by some as a frivolous diversion from the serious business of reality, may make us smarter and healthier. There is even some evidence that a sense of humor helps the human species survive.

      To understand why humor is a kind of superfood for the brain, it helps to know what our brains crave in the first place. You might think they’d prefer when we sit alone in a room and stare at a blank wall—we don’t burn up much energy doing that. But the brain is like a muscle, and it needs exercise. What gives the brain a workout? Information. When researchers asked people to look at a series of pictures while their brains were being scanned in an fMRI machine, it was the more complex images—a work of art, a sprawling vista, a group of animals—that tickled the neurons in their heads most.

      It’s the activation of those neurons— nerve cells, which, among other things, send and receive sensory information—that “lights up” the fMRI scans in bright, almost psychedelic colors. In fact, there is an almost druglike effect taking place. The brain is filled with opioid receptors—yes, opioid, as in the drug. Made of specialized proteins, these receptors poke out of our neurons like tiny radio antennas designed to pick up passing signals. When the right kind of molecule bumps into a receptor—perhaps one of the body’s naturally occurring opioids, such as an endorphin, or a synthetic drug designed to look like one, such as heroin or morphine—it can kick off a cascade of brain activity that bathes the neurons in feel-good neurotransmitters and other chemicals. The more neurons that are activated (and the more activated they are), the more pleasure we feel. In essence, learning and problem solving get us high.

      …People who study humor generally agree that most jokes are built around an incongruity—an inappropriate, absurd, surprising, or unusual combination of two fundamentally different ideas or elements….When we first see or hear this mash-up, we’re confused. That’s the setup. The punch line is the resolution of that confusion….

      So in that sense, appreciating humor is not unlike solving a puzzle, and it yields a similar kind of satisfaction. Instead of an aha moment, you get a haha moment. In fact,…because humor requires the brain to process lots of distinct types of information,…funny revelations would activate different and more disparate parts of the brain than unfunny ones. This would excite the neurons even more, which would lead to the release of more neurotransmitters and activation of the reward centers of the brain.

      …When we “get” a joke, the neurons are activated in a quick burst. When we construct a joke, activity in the same brain regions increases slowly as we rack our brains for dissimilar elements that we can link. If appreciating humor is good exercise for our brains, then writing a joke is exercise on steroids.

      Humor helps our cognition in less obvious ways too. Laughter is a natural stress reliever, and our brains work better when they aren’t slowed down by a fog of worry. In 2014, researchers in California demonstrated that elderly subjects who watched a funny video experienced significant improvements in their ability to learn and retain new information, possibly because the feelings of mirth reduced levels of cortisol, a stress hormone that has been shown to hinder recall.

      A good joke can function as a release valve for the whole body….

      …Others have demonstrated that laughter can be associated with increased blood flow, improved immune response, lower blood sugar levels, and better sleep. You don’t have to write a joke to reap the benefits. Merely experiencing humor will do the trick….

Our World in 2050

[These excerpts are from an article by Katharine Gammon in the Autumn 2019 issue of USC Trojan Family.]

      …By 2050, the reality of climate change will no longer be up for debate. The subtle signs we're starting to see around us will be more pronounced, and their impact will be easy to spot in everyday life. The warming trend can feel overwhelming to understand, much less confront—especially with so many factors believed to affect how the planet is changing. But there’s good news: Humanity has tools to shape our future…and some are already working in places across the globe….

      The 20th century was Earth’s warm-est period in nearly 2,000 years….Data he examined from a wide variety of sources, including ice cores, tree rings and coral reefs, show that the warming trend began after the industrial revolution—the 1850s. For the vast majority of the globe, the warmest temperatures have come within the past 100 years. He agrees with the broad scientific consensus that if the trend continues—and physics says it will—sea level rise and droughts could render areas of the planet unsafe or even uninhabitable…

      In the Southern California of 2050, Angelenos could spend a quarter of the year sweating it out in temperatures of 90 degrees or more. That’s 95 days of dangerously hot weather a year, significantly higher than the 67 days we see in 2019. Air conditioning will raise energy bills, but researchers anticipate costs to health as well.

      When temperatures spike, deaths rise too….Research suggests that uncomfortable heat stresses the body, increasing risk of heart problems and stroke, especially in the elderly. High temperatures have also been linked to an increase in pre-term births and infant mortality. Studies on students and stockbrokers and other workers have shown that temperatures above 80 degrees slow down thinking processes, making it harder to focus and make decisions.

      These problems disproportionately harm people with the fewest resources to deal with discomfort and health risks. Several researchers raise the alarm that any climate plan must address society's systemic inequalities….

      We don’t need to travel to 2050 to imagine the impact of climate change on the air. In spring 2018, Los Angeles’ air quality exceeded federal safety levels for 87 days….

      When temperatures rise, so does “bad” ozone. Don’t confuse this ozone with the ozone layer in the upper atmosphere, which shields Earth from the sun’s radiation. Bad ozone forms at ground level when pollutants from cars and other industrial sources react to sunlight….

      By 2050, if climate mitigation strategies and air pollution regulation don’t halt rising temperatures, the skies of Los Angeles could revert to the soupy smog of the 1970s….

      More than 90% of the warming created by humans since the 1970s has been absorbed by the oceans. And just as on land, there is a shift underway in the sea that Lwill affect the global oceans of 2050….

      Numbers of large predator fish have plunged, and about half of the world’s coral reefs have been lost to bleaching caused by warming temperatures….By 2050, most reefs may have vanished, according to a National Oceanic and Atmospheric Administration report. Some governments, like Australia’s, are taking action, trying to protect reefs by reducing other threats to coral such as dredging and runoff from land. And scientists are identifying and growing types of coral that may be better able to cope with warm water….

      Water distribution across the planet is a challenge, too: By 2050, more parts of the world will go through droughts, while others will be deluged with floods….

The Science of Sex

[These excerpts are from an article by Bennett McIntosh in the November/December 2019 issue of Harvard Magazine.]

      The “SINS OF THE MOTHER,” trumpets a headline in the journal Science, warning of a “maternal assault” against children. Another headline calls mothers “smoking guns,” the source of incalculable harm. What wrongs have these mothers committed? Not any sort of physical violence: these articles describe a series of subtle, poorly understood chemical changes, passed from mother to child during pregnancy, that cause obesity and other long-term impairments.

      But such charges stand on shaky ground….

      It’s an idea that dates hack to Aristotle, who declared that mothers had merely to glance at an object to imprint some quality of that object on her child. But in recent decades, scientists using the tools of epigenetics have examined the molecular basis for such claims as never before. Epigenetics (literally meaning “on top of” genetics) is concerned with chemical modifications to DNA that don’t change its sequence, but can still be perpetuated as cells divide, affecting genes’ function in complex but profound ways. It’s a field of compelling possibilities, demonstrating that DNA sequence is not destiny—and putting forward specific chemical explanations for why events during gestation might manifest as health prob-lems later in life.

      …While in utero exposure to specific dangers like the chemical thalidomide or diseases like rubella and syphilis has well-documented effects, those exciting early results seemed to give momentum to far-reaching claims about the dangers (or advantages) of everything from chocolate to the traumas of World War II. These claims routinely reach the public as scientific truth despite their origins in small studies and the even smaller effects they report, and despite study designs that have taken as a given that in utero effects—rather than genetic or postnatal effects—were the only effects worth considering….

      Though “gender,” in popular use, is often simply a synonym for “sex,” for the scientists and scholars who study them; they are distinct. “Sex” is the biological category: the coalescence of genes, hormones, and anatomy shaped by eons, of evolution to differentiate males and females. “Gender” is the cultural category: the “masculine” and “feminine” behavioral expectations and social roles commonly expected of the sexes.

      How did the X and Y chromosomes come to be seen as the essence of biological sex? What does that history mean for the researchers who study them—and everyone who carries them in their cells? How can medical research account for the distinct but entangled influences of sex and gender?...

Why Clean War Is Bad War

[These excerpts are from an article by Anthony Swofford in the November/December 2019 issue of MIT Technology Review.]

      …My lethality increased with each personnel addition: from me, the rifleman, to the four-man fire team, the squad, the platoon, the company, the battalion. Each time, add new men, add new hunger, more firepower, more expertise, more technology with which to lay waste to the enemy. As the fighting organism grows in size, so does the inability to pause mission and, consider whether the killing is just or moral: the killing just is.

      Every generation of American warfighters is handed excellent new gadgets with which to wage war. And who doesn’t love a new toy? Their creators become fabulously rich developing, training the military on, and helping deploy the newest technology….

      During Operation Desert Shield, the Barrett .50 caliber semi-automatic sniper rifle arrived in the Saudi Arabian desert where I and my battalion and tens of thousands of other American forces waited for war with Iraq….

      …With the Barrett we both hit iron targets out at 1,600 to 1,800 yards. The shooting was easy. The shooting was fun. We had been gifted this weapon that extended our dark arts by nearly a thousand yards. The Geneva Convention banned us from using a .50 caliber weapon on a human target, so the official reason the weapons had been released to us was to stop enemy vehicles. But we all knew the best way to stop a vehicle is to kill the driver. The technology told us so. And we listened to the technology….

      Many now profess that the young Marine or soldier with a rifle is obsolete. The greatest weapons race of all is among academic scientists trying to win DARPA funding for new warfighting technology they insist will require scant human interface with the killing act, thus relieving the combatant of the moral quandary and wounds of war. Private-sector startups sell a myth of smart war through AI, or robotic soldiers. In labs where the newest and cleanest ways to kill are being invented, the conversation is not about the morality of going to war, but rather the technology of winning. But when you rely on a myth of technology and distance killing to build a rationale for easy war, your country will lose its soul.

      …we use a $30 million aircraft to drop a JDAM (joint direct attack munition) and kill a dozen guys living in tents on the side of a mountain. What has that $30 million technological advantage bought us? The highly (and expensively) trained aviator piloting a beautifully complex flying and killing machine just extinguished some men living under canvas and sticks, men with a few thousand rounds of small arms ammo at their disposal….

      …And in a draw or valley a few klicks away from where the pilot's munitions impacted, there is another group of men living under extremely basic circumstances, eating boiled rice and maybe a little roasted meat. They will ambush an American convoy or attack a govemment-friendly village in the morning. Native grit debases our technologically superior forces and materiel. Native grit wins a war….

      At the street level, war is a people business. And people are complex. They are also fragile. Their bodies break, crumble, split open, and cease operating with surprising ease when met with the awesome newest war technology. The reality of a war-dead civilian or combatant is not changed by how advanced the tool was that delivered the fatal assault to the body.

      The lust for new defense technology is an insidious attempt to distance ourselves and our leaders from the moral considerations and societal costs of waging war. It’s not so much about the newest tools—swarm drones, exoskeletons, self-guided sniper projectiles. It is that this reliance on technological cool, the assumption that it lessens or alters the lethality of war, allows zero accountability for how, when, and why we fight.

      This is not an anti-intellectual or anti-technology argument. I am not a grunt who thinks wars can only be won with boots on the ground. However, all wars must eventually be won with boots on the ground. The problem is not the technology, but the equivocation that high-tech military armament invariably invites. If fighting war is like swiping your smartphone for an order of groceries or posting a meme to Instagram, how bad can it really be? And if a politician is seduced by the lies and supposed ease of technological warfare and leads us into a mistaken conflict, is it really his or her fault? Didn’t we all think it would be a breeze?

      The moral distance a society creates from the killing done in its name will increase the killing done in its name. We allow technology to increase moral distance; thus, technology increases the killing. More civilians than combatants die in modern warfare, so technology increases worldwide civilian murder at the hands of armies large and small….

      War was supposed to be easy or fast, because of smart bombs and the latest bit of warfighting technology. But this means nothing when years later you only see dead men, women, and children when you try to sleep.

      When we believe the lie that war can be totally wired and digitized, that it can be a Wi-Fi effort waged from unmanned or barely manned fighting apparatus, or that an exoskeleton will help an infantryman fight longer, better, faster, and keep him safe, no one will be held responsible for saying yes to war. The lie that technology will save friendly, civilian, and even enemy lives serves only the politicians and corporate chieftains who profit from war. The lie that technology can prevent war, or even create compassionate combat, is a perverse and profane abuse of scientific thinking.

Masculinity Molecule, Debunked

[These excerpts are from an article by Erika Lorraine Milam in the 1 November 2019 issue of Science.]

      Sexual desire, intelligence, strength, power, and speed. Popular culture would have us believe that these traits and more are enhanced by testosterone. For Rebecca Jordan-Young and Katrina Karkazis, such claims have transformed masculinity into the property of young, white, successful men and made this seem the natural result of a small steroidal hormone.

      Jordan-Young and Karkazis style their book as a daring push from outside the world of testosterone science, challenging long-held assumptions about the hormone….At the heart of their book is a hope of replacing readers’ beliefs that testosterone is merely biological with a nuanced understanding of how both social interactions and internal physiology affect levels of testosterone and its effects.

      Each of the book’s chapters disposes of zombie facts and “undead ideas” about testosterone that have lingered in popular culture despite repeated attempts to vanquish them. The authors label their exploration of testosterone’s influence “unauthorized,” which allows them to explore those narrative threads they find the most interesting—the confounding intellectual spaces rather than the tidy ones.

      Testosterone is not just a male hormone. It appears to play a crucial role in ovulation….

      …people hoped to be able to mobilize testosterone like a personalized precision drug. Reality proved more complicated. As Jordan Young and Karkazis make clear, the entanglements of biology and culture matter.

      These mutual entanglements are at the core of their analysis throughout the book. Risk-taking behavior, for example, has been associated with elevated testosterone in stock brokers, and Jordan-Young and Karkazis query what these results mean when some men, such as coal miners, often take risks out of financial necessity and restricted job opportunities. Risk-taking, they note, is rather less risky for those with high social status.

      Research also indicates that testosterone levels in men drop when they become parents. This might mean that men have evolved a physiological adaptation that shifts their behavior from mate seeking to involved parenting, but Jordan-Young and Karkazis point out that even this claim reinforces stereotypes that fatherhood and other masculine traits function as trade-offs. For athletes, testosterone may help build muscle mass but only in combination with rigorous workouts; the hormone alone has almost no effect.

      In broad prospect, Jordan-Young and Karkazis warn against investing too much in debates over the details of testosterone’s role in determining gender, risk-taking, parenting behavior, and fairness in athletics. They demonstrate in each case that concentrating on testosterone as a molecule draws our attention away from important social and economic sources of systemic inequality”T talk,” as they define it, therefore serves to maintain the status quo as natural. All claims about testosterone, they argue, are power moves in a competitive intellectual landscape….

Stepping out of the Dinosaurian Shadow

[These excerpts are from an article by Riley Black in the 25 October 2019 issue of Science.]

      We live in the Age of Mammals, yet warm-blooded beasts are still over-shadowed by dinosaurs. Even when considering the last great shake-up to life’s story, when an enormous asteroid triggered a mass extinction that decimated dinosaurs and gave mammals a shot at terrestrial expansion, we are often more focused on the terrible lizards lost than the furry creatures who set the stage for the Cenozoic. But a new NOVA documentary—“Rise of the Mammals” —seeks to change that and, in the process, offers viewers a window into paleontology beyond bone hunting.

      …the 1-hour program promises to tell how life surged back after the Cretaceous-Paleogene mass extinction. The catastrophe, we learn, did not just affect dinosaurs. Flying pterosaurs and seagoing mosasaurs disappeared, as did coil-shelled ammonites and huge clams called rudists, along with mass extinctions of birds, lizards, and mammals. But the mammal-versus-dinosaur competition is the film’s primary focus, with images of tiny, shrewlike insectivores living beneath the feet of dinosaurs providing the background for what follows.

      The “Mesozoic mammals as underdogs” trope should be extinct by now. In the past several decades, paleontologists have recognized that mammals thrived during this era, evolving into an impressive array of forms. All were small, fair enough, but so are most of today’s mammal species. To navigate a clear relationship of cause and effect, then, “Rise of the Mammals” emphasizes size. When did mammals start to get big?

      …Instead of following the standard—and often false—story of how a single discovery changes everything, the program follows various threads to assemble a picture of life in the first million years of the Paleocene.

      …the latter half of Rise of the film broadens in scope. “Rise of the Mammals” ends up being a short course in modern paleontology, following the story as it goes back and forth between museum and fossil outcrops. The changing face of paleontology is visible, too; the cast of scientists shown and interviewed is much more gender-balanced and diverse than many programs of the past few decades.

      The Corral Bluffs fossils are phenomenal, and what they have to tell us about the Paleocene is just starting to drip out into the published record, but the ancient ecosystem is only one small part of a global story Where the film shines—and offers something rare—are the moments when the process of science is allowed to unfold, revealing how experts assemble views of lost worlds. And if nothing else, it is helpful to pry the spotlight out of dinosaurian claws now and then.

How Life Blossomed after the Dinosaurs Died

[These excerpts are from an article by Elizabeth Pennisi in the 25 October 2019 issue of Science.]

      …Plants and animals came back much faster than thought, with plants spurring mammals to diversify…

      When the asteroid slammed into Earth, it wiped out 7596 of living species, including any mammal much larger than a rat. Half the plant species died out. With the great dinosaurs gone, 66.0 mammals expanded, and the new study traces that process in exquisite detail.

      Most fossil sites from after the impact have gaps, but sediment accumulated nearly continuously for 1 million years on the flood plain that is now the Corral Bluffs site. So the site preserves a full record of ancient life and the environment.

      Such sites can be hard to date. But Miller, a paleobotanist, and his colleagues collected 37,000 grains of pollen and spores, which revealed a clear marker of the asteroid impact: a surge in the growth of ferns, which thrive in disturbed environments. The site also includes two layers of ash from nearby volcanoes. Volcanic ash includes radioactive minerals whose decay can be used as a precise geochronological clock, providing two time markers. The known flips in Earth’s magnetic poles, which some minerals in the layers had recorded, add detail to the chronology….

      The record confirms the devastation wrought by the impact. Racoon-size mammal species had swarmed the site before the catastrophe, but for 1000 years afterward just a few furry creatures no bigger than 600-gram rats roamed a ferny world where flowering plants, with their nutritious seeds and fruits, were scarce.

      By 100,000 years later, twice as many mammal species roamed, and they were back to raccoon size. These critters foraged in the palm forests that replaced the ferns….

      Over the next 200,000 years, what he calls the “palm period” gave way to the “pecan pie” period, when walnutlike plants arose. New mammals evolved to take advantage of the nutritious seeds. Mammal diversity increased threefold, and the biggest of the new species reached 25 kilograms—beaver size.

      After about 700,000 years, legumes showed up; their fossil pea pods are North America’s oldest discovered to date. Pea and bean species from the “protein bar period” provided protein-rich meals that further boosted mammalian size and diversity….Mammals topped 50 kilograms—a 100-fold increase over those that survived the asteroid. The forests, too, had recovered….

      …no matter what happened to temperature and plant life, the loss of dinosaurs alone might have opened the door to bigger, more diverse mammals….

      The record also holds a sobering message about the future, and how quickly ecosystems might recover from ongoing, human-driven extinctions. Even a recovery that geologists call “fast” took hundreds of thousands of years, and the world was never the same….

Shootings and Social Contagion

[These excerpts are from an article by Zeynep Tufekci in the November 2019 issue of Scientific American.]

      Tragically, more than 20 percent of mass shootings, as tracked by the National Institute of Justice for the past 50 years, have occurred in the past five. The past three have been the deadliest. In the U.S., there is well-deserved attention on the availability of guns (because the deadliness of method and ease of access to weapons matter greatly) and on whether we pay sufficient attention to mental health support for troubled young men.

      But there is one more factor that is only recently getting some of the scrutiny it deserves: the role that social contagion plays in inspiring those troubled individuals to choose this course. People routinely underestimate how social humans are. We all have a viewpoint and an inner life, of course. But in the 20 years since Columbine and other mass shootings, we can say with increasing confidence what is, in retrospect, almost blindingly obvious: the shooters are inspired by those who came before—and how we react to shootings is part of the unfortunate cycle feeding them.

      We can look all the way back to ancient Greece for the archetype: Herostratus, the arsonist who burned down the second Temple of Artemis in Ephesus to immortalize his name, albeit in infamy. As Roman writer Valerius Maximus noted, “A man was found to plan the burning of the temple of Ephesian Diana so that through the destruction of this most beautiful building his name might be spread through the whole world.”

      Indeed, here I am, spreading it. In response to his terrible act, Herostratus was given the damnatio memoriae treatment: he was removedtrom all official historical records, and all public mention of him was banned. The magnitude of his crime, however, meant that he eventually found his way to some accounts nonetheless.

      Contrast damnatio memoriae with our own treatment of mass shooters. Most readers who were old enough when the Columbine tragedy happened almost certainly know the names of the shooters….Even if they are being condemned, they —I are noted, remembered and immortalized.

      Unfortunately, not everyone reacts in horror. The man who murdered 26 people at an elementary school in Newtown, Conn., an almost unfathomable crime, was obsessed with the fame and attention the Columbine shooters received….He then went on to commit his own horror.

      This is not an isolated case. We have quantitative evidence that reveals a spike in such shootings in the period following extensive mass media coverage of one, and reports and law-enforcement investigations show that many shooters study previous shooters, collect news stories about them and study their methods. In a terrible twist, they even focus on the numbers of their victims in an effort to up that count—realizing that the higher the number, the more coverage and attention they will receive in the "rankings," so to speak….

      ….damnatio memoriae may well be the correct method, as hard as it may seem.

      In the modern world, we cannot and should not censor media coverage of the event; however, we can definitely change the way we report it and talk about it. Instead of profiling the murderers, we can focus on the victims….

The Price of Warming

[These excerpts are from an article by Andrea Thompson in the November 2019 issue of Scientific American.]

      When a major heat wave engulfed western Europe in late July, Paris and other cities recorded their highest temperatures ever. The furnacelike weather did not just cause sweaty brows—it also exacted a financial toll in infrastructure damage, lost labor productivity and potentially lower agricultural yields. The situation illustrates how even relatively wealthy countries can take an economic blow from climate change.

      That is a key message of a new study from the nonprofit National Bureau of Economic Research (NBER). Much earlier research has suggested that climate-related losses would be higher for poorer, hotter countries and that colder countries could even see economic benefits from warming. But the new analysis indicates financial suffering will be widespread….

      If greenhouse gas emissions continued to grow along their current trajectory, about 7 percent of global GDP would be lost by 2100, the researchers found. Rich and poor countries, as well as those with hot and cold climates, would all see GDP losses….The U.S. would lose 10.5 percent of its GDP, whereas Canada—which some economists say could benefit from warming because of expanded agriculture—would lose 13 percent.

      Limiting emissions in accordance with the Paris climate agreement (which aims to keep global temperature rise below two degrees Celsius by 2100) would substantially stem the losses. Globally, the decline in GDP would be a mere 1 percent; in the U.S. and Canada, it would about 2 percent.

      Unlike earlier studies, this one looked not just at temperatures but at how they deviate from the normal conditions to which societies have adapted. Although rich countries such as the U.S. may have more resources to compensate for swings away from those norms, the study results make clear that adaptation alone will not prevent major losses….

End Vaccine Exemptions

[These excerpts are from an editorial by the editors in the November 2019 issue of Scientific American.]

      As of late August, there had been more than 1,200 cases of measles across 31 U.S. states this year. It’s a dispiriting comeback for a disease that was declared eliminated in this country in 2000. If the disease has not stopped spreading by the time you read this, the U.S. will likely have lost this status. The illness has been cropping up mainly in pockets of unvaccinated people. Those who choose not to immunize their families are placing at risk not only themselves and their children but also others who cannot be vaccinated because they are too young or have medical issues.

      There isn’t an iota of doubt that vaccines are an overwhelmingly safe and effective way to prevent measles and other diseases, including mumps, rubella, poliomyelitis and pertussis. All 50 states mandate that children entering school get immunized unless they have a medical exemption. Yet almost every state also offers religious exemptions, and more than a dozen offer personal belief/philosophical ones as well. California, Mississippi, West Virginia, Maine and, most recently, New York State have gotten rid of all nonmedical waivers. The others must follow suit. It’s imperative for protecting public health.

      It doesn’t take many unvaccinated people to cause an outbreak. Measles was one of the first vaccine-preventable diseases to reappear because it is so contagious; the threshold for resistance to a disease conferred by sufficient community-wide levels of immunity or vaccination—so-called herd immunity—is 93 to 95 percent. If vaccination levels fall below that threshold, an infected person can cause an outbreak.

      Hesitancy about vaccines is nothing new. People have questioned inoculations since Edward Jenner discovered the smallpox vaccine in 1796. Today vaccines are partly a victim of their own resounding success. People rarely, if ever, see once common diseases such as measles and polio, so they don’t understand their potential danger. On top of that, relentless misinformation campaigns have touted such false claims as the idea that vaccines cause autism….

      Despite the existence of religious exemptions to vaccines, most major faith groups in the U.S. do not prohibit vaccination, and many religious leaders encourage it….

      Many people who choose not to vaccinate believe no government should force them to put medicine into their bodies or their children’s. They frame the choice as a personal right, but they are not taking into account the rights of others, including their own children, to be free of disease. When it comes to balancing the two, we need to consider the needs of the community as well as those of the individual. The Supreme Court ruled in Jacobson v. Massachusetts that states have the authority to require vaccination against smallpox, and in Prince v. Massachusetts it reaffirmed that the right to religious liberty does not include the right to expose a child or the community to disease.

      Some experts argue we should just make it more difficult to obtain religious and philosophical exemptions. But unless the exemptions are removed completely, there will always be people who want to use them. Partial elimination, as the Washington State Senate enacted in the case of philosophical exemptions for the MMR (measles, mumps and rubella) vaccine alone, is also shortsighted because it sends the message that some immunizations are less important than others. The only surefire solution is to eliminate nonmedical exemptions to recommended vaccines.

      People who cannot be vaccinated for medical reasons—such as those with compromised immune systems—should of course remain exempt. But there is no legitimate argument against vaccination for the vast majority of healthy people, and there are many powerful arguments in favor of it. Refusing to vaccinate is not a matter of freedom. It's a matter of public safety.

In Defense of Science

[This excerpt is from an article by Charlie Miller in the Fall 2019 issue of EDF’s Solutions.]

      …Whenever reality collides with the president’s wishes, facts fall by the wayside, from the crowd size at his inauguration to his claim that voter fraud cost him the popular vote. On the environment, however, Trump and his enablers have taken matters to a new level.

      Government scientists have been muzzled, bad data has been used to prop up misguided policies, and research that runs counter to the administration’s id-ology has been censored.

      Exhibit A in Trump’s war on science is climate change, which Trump once labeled a hoax invented in China. Not only did he commit to withdrawing from the Paris climate agreement but he refused to sign an international statement on protecting the Arctic until all references to climate change were scrubbed….

      Trump is taking direct aim at two powerful tools for fighting climate change — the Clean Power Plan and clean car standards. This summer, the EPA completed a full-scale rollback of the Clean Power Plan, designed by the Obama administration to curb carbon emissions from power plants. In August, 22 states and seven cities filed suit to block the rollback….

Exposed: Families at Risk from Oil and Gas Pollution

[This excerpt is from an article by Shanti Menon in the Fall 2019 issue of EDF’s Solutions.]

      …Alexis has uncontrollable bloody noses that arrive unannounced. She gets rashes and bruises that no makeup can cover. Last year she temporarily lost her vision and was unable to walk. Her mother, a nurse, was dumbfounded by her symptoms — until a toxicology report revealed that Alexis had been exposed to benzene, a cancer-causing chemical that is released into the environment by oil and gas activity It’s impossible to prove where Alexis’ exposure happened, but her family's former home in McDonald, Pennsylvania, is near about 20 active oil and gas sites….

      According to a Moms Clean Air Force report, about 10 million people live, and nearly 3 million kids attend school, within half a mile of an active oil and gas site. In 2016, the Mama administration established groundbreaking national safe-guards on climate and air pollution from 36,000 new and recently modified oil and gas wells across the country. These standards…will prevent an estimated 300,000 tons of climate-polluting methane, 150,000 tons of smog-forming chemicals and 1,900 tons of benzene and other hazardous pollutants from getting into our air in 2020 alone. They ensure stronger protections for communities and lay the groundwork for future safeguards on 850,000 older drilling sites.

      The Trump administration tried to prevent these protections from taking effect, an attempt EDF blocked in court. Now the administration is trying to eliminate all federal methane regulation, despite the heartbreaking protests of people like Alexis….

      Some major players in the oil and gas industry are also opposed to the planned EPA rollback. Shell, BP, Exxon Mobil and Equinor have all voiced support for federal methane regulations. These companies and others have set their own methane reduction targets, and some are testing new methane monitoring technologies, which EDF helped develop.

      Ultimately, there’s no substitute for strong federal pollution standards….

A Defining Moment for Democracy

[These excerpts are from an editorial by Randi Weingarten in the Fall 2019 issue of American Educator.]

      …President Trump has trampled rights enshrined in the Constitution and waged a war on truth. He has fanned biases that aim to dehumanize “the other” and that erode our democracy. He is enamored of despots, and distances our allies. He has put commerce and greed over human rights.

      Trump boasts that the economy is the “best ever,” but nearly all of the benefits of economic growth have gone to the wealthiest Americans and large corporations, while millions of Americans tread water. Forty percent of Americans say they couldn’t cover a $400 emergency. More than 28 million Americans are uninsured. Today’s average wage has the same purchasing power as in 1978. The median American family has just $5,000 saved for retirement. Americans hold $1.6 trillion in student debt. And teachers, who routinely spend their own money on supplies for their students, are paid almost 20 percent less than similarly educated professionals.

      Yet Trump is not addressing these problems. Instead, he is stoking America’s divisions in order to exploit them….

      Americans must be clear-eyed about the perilous time we are in. We must think seriously about what we can do to take a stand, and about the implications of doing nothing. We can’t ignore Trump’s bigotry and cruelty, or the fact that his erratic behavior is intended to create chaos and confusion. And we can’t assume things won’t get worse….

Lithium-ion Battery Development Takes Nobel

[These excerpts are from an article by Robert F. Service in the 18 October 2019 issue of Science.]

      You probably have the work of Nobel Prize winners in your pocket. This year's Nobel Prize in Chemistry was awarded last week to the pioneers of the lithium-ion battery, an invention that has become ubiquitous in the wireless electronics that permeate modern life: your phone, tablet, laptop, and perhaps even your car. Lighter and more compact than the rechargeable batteries that preceded them, lithium-ion batteries are now moving beyond gadgets to power homes, airplanes, and even the electric grid that feeds power to entire cities….

      Virtually all batteries have three essential components: two electrodes—an anode and a cathode—separated by an electrolyte. In today’s lithium-ion cells, the electrolyte is typically a liquid that allows lithium ions to move back and forth between the electrodes. When the battery is providing electricity, lithium atoms at the anode give up electrons that flow through an external wire. The positively charged lithium ions left behind migrate through the electrolyte to the cathode, where they nestle between the cathode’s layers of metal oxide materials. Applying an electric voltage to charge the battery reverses the flow, pushing the lithium ions out of the metal oxide, through the electrolyte, and back to the anode, where they retrieve electrons.

      …repeated charging deposited thin whiskers of lithium, known as dendrites, on the anode, causing some batteries to short out and catch fire….

      For starters, battery researchers are working feverishly to do away with cobalt, an expensive metal often mined by child laborers in the Democratic Republic of the Congo, which supplies some 70% of the world’s total. Current lithium-ion batteries reduce the need for cobalt by mixing in manganese and nickel, but stabilizing the layered cathode still requires some cobalt….

      Another major research thrust is replacing liquid electrolytes with polymers and other solid materials. If perfected, solid electrolytes could enable researchers to return to using solid lithium anodes without fear of creating dendrites. That could lead to batteries able to store enough energy to propel electric vehicles as far as gas-powered cars without recharging, power short-hop electric planes, and even store backup electricity from wind and solar plants to light up cities at night and when the wind is still….

Sauropods Get a New Diet and a New Look

[These excerpts are from an article by John Pickrell in the 18 October April 2019 issue of Science.]

      How did sauropod dinosaurs, the biggest creatures ever to have thundered across Earth, bulk up to the weight of more than 10 African bull elephants on a spartan diet of prehistoric greens? Many herbivores today grow fat on energy-rich grasses, but these and other nutritious flowering plants didn’t become common until near the end of the dinosaurs’ reign. Now, researchers think they have glimpsed the answer: a surprisingly nutrient-rich plant that could have been a mainstay of these dinosaurs’ diets, and turtlelike beaks that buttressed sauropods’ peglike teeth as they relentlessly stripped foliage from plants.

      …sauropods were eating machines that gulped down vegetation without chewing. They swung their long necks over vast areas, like prehistoric lawn mowers, while saving energy by keeping their bodies in one spot. The new studies add detail by exploring the beasts’ diet and jaw structure.

      …identified what may have been the superfood of the dinosaur era. Her team zeroed in on the nutritional content of low-growing, spore-bearing horsetails, or Equiserum, which were widespread during the Jurassic period and still grow today.

      Horsetails appeared to be poor fodder in previous tests, which simply burned the plants to measure carbon content….They fermented modern horsetails for 3 days to simulate the journey through a sauropod's gut and measured the volume of gas produced—an indicator of energy content. The researchers were astounded to find that horsetails released more energy than any other plant group, including 16 modern grasses. Equisetum is rich in protein, they say, and far more nutritious than the ferns, cycads, and conifers common in the dinosaur era….

      Even eating superfoods, sauropods must have vacuumed up as much as 1 ton or more of plant matter per day. To understand the mechanics, another Bonn team analyzed the beasts’ jaws.

      For decades, paleontologists have dug up puzzling fossils: rows of isolated sauropod teeth, still neatly arranged as they would have been in the mouth, with not a scrap of bone encasing them….

      …Instead of the lizardlike lips shown in artists’ concepts, the behemoths likely sported beaks as well as teeth, unlike any living animal.

      The researchers found that sauropod teeth typically show surface wear only about halfway down to the jaw. That suggests the teeth were once deeply embedded in a supporting structure. The researchers also found tiny pits in the surface of the jaw, perhaps indicating blood vessels to nourish beaks. Similar pits and foramina are seen in other dinosaur bones near inferred structures, like the sheaths covering horns, thought to have been made of keratin, which forms our nails and birds’ beaks and feathers.

      Poropat cautions that expanded gum tissue, rather than a beak, might have held the teeth in place. But bony scaffolding that supported beaks is obvious in other dinosaurs, including Triceratops, Stegosaurus, and duck-billed hadrosaurs….

Bringing Clarity to Science Instruction

[These excerpts are from an article by John Almarode, Douglas Fisher and Nancy Frey in the October 2019 issue of The Science Teacher.]

      Through teaching science, we have the pleasure of developing and implementing learning experiences that allow students to discover how the world works….Interweaving the laws, principles, and theories of the universe with scientific practices that have allowed scientists to discover these ideas is the focus of teaching and learning in the science classroom. The overall intention is that learners will walk away with the ability to engage with science-related issues, and with ideas and processes or practices of science beyond the walls of the classroom—the definition of scientific literacy….We want our learners to take ownership of their learning in pursuit of knowing and understanding things in the world….

      The learners in these classrooms are just waiting to be entertained by the demonstration, checking off the steps in a laboratory investigation, memorizing discrete facts, doing science only when they are in the science classroom, and learning textbook definitions of words. These situations do not provide an authentic context that is relevant to these adolescent learners. What results is that students are no closer to three-dimensional learning (science and engineering practices, disciplinary core ideas, and crosscutting concepts) as envisioned by the National Research Council and articulated in the Next Generation Science Standards, much less scientific literacy….

      Planning and implementing cohesive science learning experiences that build and utilize science knowledge to explain phenomena, while at the same time drawing on problem-solving within that context is more than just clarity. However, without clarity about learning, students are less likely to make meaning of these experiences, and thus not engage in working toward the learning intentions or goals in the science classroom….

      Clarity refers to the overall awareness of the teacher and the learners regarding what the science learning is for that day or class period, why we are learning this science content or engaging in these practices of science, and what successful learning looks like. Put differently, for learners to have clarity in the science classroom simply means they must know the what, why, and how of the day’s learning….

Deforestation

[These excerpts are from an article by Chris Anderson in the October 2019 issue of The Science Teacher.]

      From the boreal forests in Siberia and Canada to the temperate deciduous forests of eastern North America and Europe to the tropical rain forests that encircle the Earth’s equator, forests occupy nearly a third of the land surface on our planet and provide a foundation for nearly all terrestrial ecosystems.

      This month, the world watched in stunned disbelief as wildfires broke out across 5.5 million acres of the Amazon rainforest. Dry weather, wind, and heat has burned up an ecosystem already under threat from agriculture, logging, and mining.

      Sadly, the inferno raging in one of the last few treasure troves of biodiversity on our planet is not an isolated ecological disaster. Wildfires are consuming wilderness in Siberia, Indonesia, Central Africa, and Alaska. Fires are not the only cause, however. Our forests are being cut down at an unprecedented rate.

      Whether it’s for expanding agriculture for cattle and palm oil, mining, or human development, an area equal to 27 soccer fields of the Earth's forests is destroyed every minute. Approximately 18.7 million acres of forest are felled annually, larger than the island of Ireland. In the last few months, Brazil has opened up even more of the precious remaining Amazon to resource extraction.

      …Getting our students to see the relevance of forest being destroyed thousands of miles away when the impacts may not be felt in their daily lives is our biggest challenge. The key is to highlight how fewer forests, whether it’s down the street or on another continent, will make their air and water dirtier, make them sicker, and make their world a hotter place to live.

      …Understanding how the global economy affects the natural world is a great way to show deforestation’s impact on students’ lives and offers many potential cross-curricular projects for willing history and social studies teachers.

      After giving the students some background on the causes and impacts of deforestation, the easiest and most obvious application is in biology, where teachers can use deforestation as a theme for discussing biodiversity, populations, tro-phic levels, and biogeochemical cycles….

      Energy cycling throughout ecosys-tems is another excellent concept to apply to deforestation….

      Understanding the human impact on the environment may be the most important lesson we teach our children. When kids understand that forests make our world a cleaner, cooler, healthier, and more peaceful place, they will fight to protect it….

Bad Bites

[These excerpts are from an article by Steve Mirsky in the October 2019 issue of Scientific American.]

      …Most people are probably more frightened of sharks than they are of mosquitoes—it's tough to get too worked up over something you can swat. But as author Timothy Winegard points out, sharks kill fewer than 10 people annually, whereas the average yearly mosquito-related death toll over the past two decades is about two million. Mosquitoes are the deadliest predator of people on the planet.

      The runner-up killer of human beings is—you guessed it—human beings. In that same stretch, we’ve offed about 475,000 of our fellows on average annually….Granted, it would be tough for 7.7 billion humans to outkill the 110 trillion mosquitoes that are alive at any time. That's more than 14,000 of them for every person. In the Arctic during the summer, they can completely cover something (or someone) edible in a flash. “Ravenous mosquito swarms,” Winegard writes, “literally bleed young caribou to death at a bite rate of 9,000 per minute, or by way of comparison, they can drain half the blood from an adult human in just two hours.”

      Of course, human expiration via exsanguination by mosquito is exceedingly rare. “It is the toxic and highly evolved diseases she transmits that cause an endless barrage of desolation and death.” Winegard writes. He uses “she” because only females bite, attracted to us mostly by the carbon dioxide exhalations that they can detect up to 200 feet away. They also like really smelly feet. So if you think you can hide in plain sight by holding your breath, be sure to also wash between your toes before you pass out.

      Of the more than 15 diseases mosquitoes transmit, the deadliest—malaria—has been sickening animals for an exceedingly long time. “Amber-encased mosquito specimens contain the blood of dinosaurs infected with various mosquito-borne diseases, including malaria….”

      The book claims that mosquito diseases played a critical role in the American colonists' underdog win in 1783 against the British in the Revolutionary War. George Washington, himself a malaria sufferer, “had the advantage of commanding acclimated, malaria-seasoned colonial troops.” Meanwhile many British troops had never been exposed and were mowed down by the kill-buzz….

Smart Start

[These excerpts are from an article by Lisa Guernsey in the October 2019 issue of Scientific American.]

      …In many preschool classrooms in the U.S., children are asked to do little more than identify shapes and letters and sit quietly on rugs during story time. But a growing body of research is overturning assumptions about what early education can look like….when children learn certain skills, such as the ability to focus attention—skills that emerge when teachers employ games and conversations that prompt kids to think about what they are doing—the children do better socially and academically for years afterward. A study published last year, which tracked kids for a decade starting in preschool, found some evidence that children with teachers trained to foster such abilities may get better grades com-pared with children who did not get this type of education.

      Politicians routinely promise to give more money to prekindergarten schooling….But experts say that to do right for kids, any program will need to focus on at least two foundational skills: executive functioning and oral language.

      Executive function involves a suite of cognitive skills, such as being able to hold an idea in one’s head and recall it a short time later (working memory), the ability to control impulses and emotions, and the flexibility to shift attention between tasks. Oral language skills mean not just expressing sounds and words but using them in meaningful conversations that involve increasingly complex sentences.

      …a few decades ago cognitive scientists and behavioral researchers began to examine how and when children develop the ability to “self-regulate”--to know when to control emotions and how to follow through on tasks even when they might be difficult….(The term “self-regulation” some-times is used interchangeably with “executive function.”)

      …Opportunities to practice independence and autonomy may be another key ingredient. A 2018 study in the Journal of Applied Developmental Psychology links improvements in children’s executive function to the extent to which adults give them a little autonomy….

Monsters of the Mesozoic Skies

[These excerpts are from an article by Michael B. Habib in the October 2019 issue of Scientific American.]

      …Pterosaurs were the first vertebrate creatures to evolve powered flight and conquer the air—long before birds took wing. They prevailed for more than 160 million years before vanishing along with the nonbird dinosaurs at the end of the Cretaceous period, around 66 million years ago. In that time, they evolved some of the most extreme anatomical adaptations of any animal, living or extinct. The smallest of these aerial predators was the size of a sparrow. The largest had a wingspan that rivaled that of an F-16 fighter jet. Many possessed heads larger than their bodies, making them, in essence, flying jaws of death. Pterosaurs patrolled every ocean and continent on Earth. No animal in the Mesozoic would have been safe from their gaze.

      Unlike dinosaurs, which are survived today by birds, pterosaurs left behind no living descendants. As a result, all that paleontologists know about pterosaurs comes from the fossil record. And that record has been frustratingly fragmentary, leaving us with just a glimmer of their former glory and a host of questions about their bizarre anatomy and ill fate. Paleontologists have scratched their heads over these mysteries for decades. Now new fossil discoveries, combined with mathematical modeling methods in which anatomical structures are simplified just enough that equations of physical properties can be applied to get best estimates of strength, weight, speed, and so forth, are finally generating insights. And what scientists are finding is that pterosaurs were even more extraordinary than we ever imagined….

      One of the enduring mysteries of pterosaurs is how the largest members of this group became airborne. Giants such as Quetzalcoatlus, first discovered in Texas, and Hatzegopteryx, from modern-day Romania, stood as tall as a giraffe and had wingspans of more than 30 feet These animals possessed jaws twice the length of those belonging to Tyrannosaurus rex. Their upper arms would have been nearly as large around as the torso of an average-sized adult human. They were true behemoths, attaining weights exceeding 650 pounds. For comparison, the largest bird to ever take to the air—Argentavis, living six million years ago in Argentina—most likely weighed less than 165 pounds.

      The discrepancy between the biggest members of each of these groups is so vast, in fact, that multiple researchers have suggested that the largest pterosaurs could not fly at all (although this would be puzzling given their many anatomical adaptations for flight). Others have suggested that they could fly but only under very special air and surface conditions—if the atmosphere in their day were denser than it is today, for instance. After all, it seems unfathomable that birds of such sizes could fly. In fact, recent power-scaling studies from several researchers, including me, have demonstrated that supersized birds would have insufficient power to launch themselves into the air in the first place.

      But pterosaurs were not birds. Indeed, over the past decade my colleagues and I have carried out numerous calculations of pterosaur launch and flight power, showing not only that giant pterosaurs could launch and fly but also that they probably did not need any special circumstances to do so. In line with these conclusions, we now know from geochemical analyses of sedimentary rocks and microanatomical analyses of plant fossils that air and surface conditions in the Late Cretaceous—the heyday of enormous pterosaurs—were not remarkably different from what we experience today. What was different, and unique, was the anatomy of pterosaurs.

      There are three things that an animal needs to be able to fly at gigantic sizes. The first is a skeleton with a very high ratio of strength to weight, which translates to a skeleton with large volume but low density. Pterosaurs and birds both have such skeletons: many of their bones are quite hollow. The walls of the upper arm bone of Quetzalcoatlus, for example, were about 0.12 inch thick—comparable to an ostrich eggshell—yet the bone had a diameter of more than 10.5 inches at the elbow.

      The second thing that a giant flier needs is a high maximum lift coefficient. This number describes how much lift the wings produce for a given speed and wing area. At a high lift coefficient, an animal can be heavier because its wings will support more weight at a lower speed. This relation, in turn, means the creature needs less speed on takeoff, which makes a huge difference in the muscle power required for launch. Membrane wings, such as those of pterosaurs and bats, produce more lift per unit speed and area than the feathered wings of birds. This additional lift improves slow-speed maneuvering capability, which for small animals helps with making tighter turns and for big animals facilitates takeoff and landing.

      The third and most important prerequisite is launch power. Even with very efficient, large wings, a big flier still needs to produce lots of leaping power to become airborne. Flying animals do not flap their way into the air or use gravity to take off from an elevated location such as a cliff. Wings do not produce much lift at low speeds, and gravity launching would mean trying to take off by accelerating in the wrong direction—a dangerous prospect. Instead, a powerful jump provides critical speed and height to begin flight. Increased leaping power yields better launching power. Large fliers therefore need to be good jumpers.

      Many birds can manage impressive leaps. They are constrained by their heritage as theropod dinosaurs, however: like their theropod ancestors, all birds are bipedal, meaning they have only their hind limbs to use for jumping. Pterosaurs, in contrast, were quadrupedal on the ground. Their wings folded up and served as walking, and therefore jumping, limbs. Numerous exquisitely preserved fossil trackways confirm this odd aspect of pterosaur anatomy. Being quadrupedal drastically changes the maximum size of a flying animal. Pterosaurs could use not only their hind limbs for launch but also their much larger forelimbs, thereby more than doubling the available power for takeoff. They had the perfect combination of adaptations to become aerial behemoths.

      Previous studies have modeled bipedal launches for giant pterosaurs. For example, in 2004 Sankar Chatterjee of Texas Tech University and his colleague worked out how Quetzalcoatlus could propel itself into the air using only its hind limbs. But the researchers determined that for that approach to work, the animal could not weigh more than 165 pounds and had to run downhill into a headwind. The quadrupedal launch allows for more realistic body weight and less restrictive environmental conditions.

      …The proportions of pterosaurs are downright bizarre. All pterosaurs had oddly proportioned limb elements. Their hands, for example, are probably the most specialized in all of the vertebrate world, with an immense fourth finger that supported the wing. Yet this is not especially surprising in and of itself because that unusual hand was intrinsic to the pterosaur wing and the animal’s ability to fly. What really confuses scientists and enthusiasts alike is not the wings of pterosaurs but the heads.

      Even early pterosaurs had decidedly large noggins. The head on Rhamphorhynchus, a representative species from 150 million years ago, in the Late Jurassic period, was nearly as long as its body. Then in the Cretaceous head size got even more extreme. Fossils of species such as Quetzalcoatlus, as well as Anhanguera from Brazil, show that pterosaurs got bigger on average, but their heads became proportionately gigantic. The skull on a rather typical Cretaceous pterosaur might be two or even three times the body length (usually taken as the distance between the shoulder and hip). Some had skulls surpassing four times the length of their bodies. The braincases on these animals were not terribly large, though. It is mainly the faces and jaws that expanded to an outrageous degree. Bony flanges under the jaw, towering crests atop the cranium and other elaborations further exaggerated pterosaur skull anatomy. In all, the head could almost seem like it was from a different animal than the body.

      The oddities do not end there. Whereas in most animals, including humans, the bones of the neck are among the smallest in the spine, the neck vertebrae in pterosaur specimens are often the largest. In fact, the neck vertebrae are often twice the volume of the vertebrae in the torso. One of the newest additions to the pterosaur family tree offers a great example of this trend….It has neck vertebrae that are nearly as long and twice as strong as its humerus, the wing bone to which most of the flight muscles attach and that does most of the work to keep the animal up in the air. In some species the neck is triple the length of the torso, with the head size triple again, such that the head and neck could make up more than 75 percent of the total length of the pterosaur. Why would any animal be so ridiculously proportioned? And how could such a body plan possibly work for a flying creature?

      Specialists are still working out why pterosaurs ended up with such crazy anatomy, but one probable explanation is what I call the “if it were easy, everyone would do it” hypothesis. In short, having a big set of jaws to eat with and a big face with which to signal to mates and rivals might be a great option for a lot of animals if the costs associated with these traits were not normally so prohibitive. For example, mammals have big braincases, so mammal heads become very heavy as they grow larger in overall dimensions. Pterosaurs might have stumbled into a developmental zone where the proportions of the face were less coupled to those of the back of the skull. This would have allowed them to evolve a giant set of jaws without having a huge braincase.

      Pterosaurs also had extra openings in their skulls, the large of which was an opening in front of the eyes known as an antorbital fenestra. Dinosaurs had this opening, too, but pterosau took it further, in some cases evolving an opening so large that the torso skeleton could have fit inside it. This opening would have been covered with skin and other tissues in life and probably would not have been visually obvious, but it made the skull quite light relative to its volume. The bones of the skull might also have had large air spaces within them, similar to the air-filled skull bones of some living birds.

      Even with these weight-saving features, however, pterosaurs’ heads were often so colossal that they still would have been quite heavy. Perhaps counterintuitively, the fact that they were flying animals may have worked in their favor in this regard. The main problem with a heavy head is not the overall increase in body weight. Rather it is the disproportionate effect that the skull weight has on the animal’s center of gravity. A huge head, especially if mounted on a huge neck, moves the center of gravity quite far forward. For a typical walking animal, this creates a serious problem with gait: the forelimbs have to move into an awkward forward position for the animal to be balanced. But pterosaurs had enormous forelimbs purpose-built for flight.

      …when a pterosaur was walking, those forelimbs were positioned just about right to take up the weight of the head, neck and chest. Most of the propulsion dur ing walking came from the legs, so pterosaurs could hold the weight of their hefty heads on their extrabulky arms and push themselves along with their much more normal-sized hind limbs….

      This arrangement would not have made for the most efficient walking gait, but it was doable. And anyway, pterosaurs traveled primarily by flying. Pterosaur species with especially long, narrow wings, like those of some modern seabirds, might have flown continuously for months or even years, touching down only to mate or lay their eggs. The pterosaur Nyctosaurus may have had the most efficient wings—and thus the longest continuous soaring flight—of any vertebrate animal ever.

      In the air, the center-of-gravity problem becomes much easier to deal with. For an animal to be stable in the air, its center of lift and center of gravity must be in alignment. This might seem like a difficult prospect for a creature with a supersized head and a correspondingly forward center of gravity. But a pterosaur’s center of lift was close to the front of a wing, which means that the animal needed only to angle its wings moderately for-ward from the root to align the center of lift with the center of gravity….Forward-swept wings can themselves be sources of instability, but the flexibility of pterosaur wings and the rapid cerebellar reflexes that all vertebrate creatures possess could have compensated for it….

      Why did pterosaurs suffer a fate worse than that of the birds at the end of the Cretaceous? One reason might be their tendency to grow large. Hardly any land animals with an adult body mass of more than 44 pounds survived that apocalyptic time….When the asteroid struck, it vaporized part of Earth’s crust, along with much of itself, and the reentry of this superenergized rock-metal cloud essentially set the sky on fire around the world….global soaring conditions might well have been ruined for a month after the impact—enough time to starve every pterosaur that needed to soar to eat….

      Although it ends with extinction, the story of pterosaurs is one of success: they were the ultimate aerial giants, having evolved a dazzling array of extraordinary anatomical features not seen in any other group before or since. From them we have learned much about the limits of animal form and function. Those lessons help us understand the history of Earth and the complexity of ecology. They are even inspiring new technologies, including novel aircraft designs. Their fossil record is a thrilling window into a bygone world filled with real flying monsters. Pterosaurs were not just extreme—they were exceptional.

The Precautionary Tale of Golden Rice

[These excerpts are from an article by Andrew J. Wright in the 11 October 2019 issue of Science.]

      The term genetically modified organisms (GMOs) inspires images of crazy crops: a single plant that bears tomatoes above ground and potatoes beneath, or a tree that bears a fruit with stripes of yellow sour orange and green stripes from citron. Unlikely as they may sound, the two plants described above are very real, although neither was made in a laboratory. They are products of simple grafting, a technique used by horticulturalists for thousands of years. In Golden Rice: The Imperiled Birth of a GMO Superfood, science writer Ed Regis explores why certain food plants are treated by regulatory authorities and the public as “genetically modified,” and therefore worthy of strict cautionary regulation, whereas others are seen as “natural,” despite intensive human intervention in their growth and development.

      The book’s title refers to rice whose yellow grains have been genetically altered to express beta-carotene to address the widespread problem of vitamin A deficiency, symptoms of which include frequent infections, blindness, and even death. Vitamin A deficiency is estimated to affect one in three children under the age of 5, claiming 670,000 lives every year. The idea behind golden rice was that expressing beta-carotene, a vitamin A precursor that occurs in other parts of the rice plant, in the grain, would facilitate the delivery of the vitamin to children in Africa and Southeast Asia, whose main diet is rice.

      Golden Rice is a thoughtful and carefully documented tale of how difficult it can be to take something that works in the laboratory and get it to the people who stand to benefit from it. Regis puts his cards on the table from the start, dedicating the book to the scientists who led the development of golden rice. But he also makes clear that these researchers were responsible for some of the missteps that thwarted the rice’s journey….

      From a scientific standpoint, the technology was a success. So, what prevented golden rice from being quickly disseminated? Although Greenpeace and other anti-GMO activists have been vocal critics of the project, Regis also points to another culprit: the Precautionary Principle.

      The Precautionary Principle, cited in the Cartagena Protocol of 2000 (an international agreement on biosafety), allows countries to restrict, postpone, or ban any product or technology without offering any evidence that the item poses a threat or danger—“better safe than sorry” writ large. Many years of the Golden Rice Project have thus been spent attempting to comply with stringent regulatory hurdles….

      Although nuclear energy has Chernobyl and pharmaceuticals has thalidomide, Regis points out that no such disaster exists for GMOs. (A suspected link between Monarch butterfly decline and Bt corn might have fit the bill, but these claims were later debunked by numerous studies.) While one could argue that it is better to be proactive than to wait for a tragedy to occur before taking precautions, Regis invites the reader to consider whether it may be worth the unknown risks ostensibly being prevented by regulation to prevent the death and disability that is known to accompany vitamin A deficiency.

      After millions of dollars and years of effort, the United States, Canada, Australia, and New Zealand have all recently approved golden rice as safe for consumption. Now, the end goal is in sight: Golden rice is in front of regulators in the Philippines and in Bangladesh, where it is expected to Lbe approved by the end of 2019.

Confronting Climate Change

[These excerpts are from an article by Miriam Aczel in the 11 October 2019 issue of Science.]

      …In On Fire, writer and activist Naomi Klein distills the development of the climate change mitigation movement over the past decade into a series of thoughtful essays that poignantly highlight the dire situation of the planet. At the same time, she chronicles the unfolding of a “people’s emergency;” characterized by tidal waves of climate-focused civil disobedience.

      The largest threats—rising sea levels and increased flooding, droughts and famines, rising global temperatures, and increasing extreme weather events—are also harming livelihoods, deteriorating services and wages, and disproportionately affecting the poor. We have a “once-in-a-century chance to fix an economic model that is failing the majority of people,” Klein argues. And although the transformation would require ending current consumption patterns, confronting the climate crisis, Klein contends, would lead to creation of millions of good jobs, guaranteed health care, and opportunities for the most “systematically excluded” populations.

      A key threat to concerted action is climate skepticism, coupled with a drastic shift in the intensity of emotional responses related to climate issues. When challenging a person’s position on an issue means challenging a central tenet of their identity, facts can be perceived as attacks and are easily deflected. Klein maintains, however, that enhancing communication and tying climate change to other concerns, including the economy and social justice, will help mitigate these threats.

      Amid increasing tension between climate advocates and those disavowing climate change, a shift in values is occurring. Today’s activists understand that to change environmental policy requires confronting the values of “rampant greed and individualism” that led to the economic crisis. Social change, Klein contends, begins with radically altering how we relate to each other (and to nature), accepting our collective responsibility to future generations, and respecting the interconnection of all life.

      …In The Green New Deal, Rifkin confronts skepticism about the feasibility of making a transition of the scale required by countering that we are already making these changes in many global regions. It is time, he argues, for the United States to join the E.U. and China as leaders toward a zero-carbon economy.

      …we are currently entering the “green digital Third Industrial Revolution,” a paradigm shift in which ownership is replaced with access. The “sharing economy”—made possible by digital infrastructures of energy, communication, and mobility—is, he argues, the first economic system to have emerged since capitalism and socialism. Although the federal government will play a crucial role in framing the transformation, he writes, in today’s increasingly “laterally distributed glocal era,” municipalities and local counties are particularly equipped to play an important role.

      …a “carbon bubble” —in which fossil fuel prices will be reduced to compete with renewable prices-- would lead to economic and environmental damage if not deflated early. He believes that we can avoid this with rapid decarbonization….

Obesity on the Brain

[These excerpts are from an article by Ellen Ruppel Shell in the October 2019 issue of Scientific American.]

      …Among those views is the idea that particular nutrients such as fats, carbs or sugars are to blame for our alarming obesity pandemic. (Globally the prevalence of obesity nearly tripled between 1975 and 2016, according to the World Health Organization. The rise accompanies related health threats that include heart disease and diabetes.)….a dramatic shift in how we make the food we eat—pulling ingredients apart and then reconstituting them into things like frosted snack cakes and ready-to-eat meals from the supermarket freezer—bears the brunt of the blame. This “ultraprocessed” food…disrupts gut-brain signals that normally tell us that we have had enough, and this failed signaling leads to overeating.

      …His first study found that, contrary to many predictions, a diet that reduced carb consumption actually seemed to slow the rate of body fat loss. The second study, published this year, identified a new reason for weight gain. It found that people ate hundreds more calories of ultraprocessed than unprocessed foods when they were encouraged to eat as much or as little of each type as they desired. Participants chowing down on the ultraprocessed foods gained two pounds in just two weeks….

The Physicist and the Dawn of the Double Helix

[These excerpts are from an article by Karl Sigmund in the 4 October 2019 issue of Science.]

      Three quarters of a century ago, Nobel laureate Erwin Schrodinger published What Is Life?, which described the forays of a “naive physicist” into biology and suggested that hereditary properties are encoded in an “aperiodic crystal.” A meme was born that changed the life sciences forever….

      What Is Lift? became one of the most important science books ever, not for its content (whose limitations were soon evident) but for its influence on a cohort of brilliant scientists. Almost all of the protagonists of the double helix saga acknowledged, at one time or another, the impact of Schrodinger’s book (the one possible exception being crystallographer Rosalind Franklin, who died before writing her memoirs)….Many of them—including Francis Crick, Maurice Wilkins, and Seymour Benzer—were physicists, but some were chemists (such as Erwin Chargaff and Gunter Stent) or physicians (such as Francois Jacob). Even a teenage bird watcher named James Watson became “polarized towards finding out the secret of the gene” after reading Schrodinger's booklet….

      Schrodinger’s prescient vision of genetic coding is one message in What Is Life?. Another is that cells create order from order….

      Six months after the discovery of the double helix, and a mere 10 years after the Dublin lectures, Francis Crick sent a letter to Schrodinger, acknowledging the impact of What Is Life? on both himself and Watson. Schrodinger did not reply. Even stranger, he never returned to biology….

Parched Peatlands Fuel Indonesia’s Blazes

[This excerpt is from an article by Dennis Normile in the 4 October 2019 Science.]

      Once again haze is suffocating Indonesia, but some scientists say it could have been worse. Acrid smoke from fires set to clear land for agriculture has sent scores to hospitals with respiratory problems and closed thousands of schools in Indonesia and neighboring Malaysia. At its thickest, in mid-September, more than 100 flights had to be canceled because of poor visibility. Although the government has tried to seed clouds for rain and dump water from the air, only the monsoon rains due later this month are likely to quench the fires.

      Yet countermeasures Indonesia has taken since the last major haze event, in 2015, have helped limit this year’s disaster. A new agency is restoring degraded peatlands, where agribusiness has drained and dried out meters-thick layers of waterlogged vegetation, making it vulnerable to ground fires that are almost impossible to stop. The government has also beefed up a moratorium on the conversion of prime forest land underlain by peat….But virtually all experts agree that more is needed, including stricter enforcement of a ban on setting fires.

      Small farmers in Indonesia have long practiced slash-and-burn agriculture, and in recent decades large corporations have industrialized the practice. They own long-term concessions to develop plantations within publicly owned forests, many in swampy landscapes rich in organic material. Concentrated in the coastal plains of Sumatra, Borneo, and Papua, these peat forests provide a habitat for rare species such as orangutans, leopards, Sumatran tigers, tapirs, white-winged ducks, and freshwater turtles. But in the 1980s, concession holders started to dig drainage canals through peatlands to float out logs and dry out the peat to plant dryland crops, especially oil palm and acacia trees for pulp and paper. Fires they set to clear the land can burn out of control.

      Peatlands play an outsize role in the hazes because dry underground peat deposits provide “an inexhaustible supply of fuel”….And because the very ground is burning, “the fires can’t be contained until the monsoon.” They release not just smoke, but vast quantities of greenhouse gases. Indonesian tropical peatlands, 36% of the world's total, hold an estimated 28.1 gigatons of carbon, according to a 2017 study—more than all the country’s upland forests.

      The conflagrations are paced by the weather. In 2015, an El Nino in the western Pacific Ocean combined with another irregularly recurring climatic phenomenon called the Indian Ocean dipole to make Indonesia’s typically dry summer even drier….Fires raged from late June until the end of October, burning 2.6 million hectares, an area half the size of Costa Rica. The haze affected countries as far away as Thailand and the Philippines….

      To remove the Incentive to set fires—as well as preserve Indonesia’s remaining rainforests—the government in 2018 decided not to grant new licenses for oil palm plantations, instead focusing on boosting yields from existing sites and lessening their environmental impact….And in August, Indonesia made permanent a temporary moratorium on converting primary forests and peatlands to agricultural use. The government has also promised stricter enforcement of laws that make concession holders responsible for fires in their holdings, regardless of whether they are deliberately set. Penalties can include criminal prosecution.

      Because the years since 2015 have been relatively wet, the measures had never really been tested—until this year. The Indian Ocean dipole again gave Indonesia an extremely dry summer….

Language and the Brain

[These excerpts are from an editorial by Lera Boroditsky in the 4 October 2019 issue of Science.]

      Languages—exquisitely structured, complex, and diverse—are a distinctively human gift, at the very heart of what it means to be human. As such, language makes for both a particularly important and difficult topic in neuroscience. A dominant early approach to the study of language was to treat it as a separate module or organ within the brain. However, much modern empirical work has demonstrated that language is integrated with, and in constant interplay with, an incredibly broad range of neural processes.

      Unlike other areas of neuroscience investigation (e.g., vision, motor action) that have relied heavily on invasive techniques with animal models, the study of language lacks any such model….

      At the same time, language is a powerful engine of human intellect and creativity, allowing for endless recombination of words to generate an infinite number of new structures and ideas out of “old” elements. Language plays a central role in the human brain, from how we process color to how we make moral judgments. It directs how we allocate visual attention, construe and remember events, categorize objects, encode smells and musical tones, stay oriented, reason about time, perform mental mathematics, make financial decisions, experience and express emotions, and on and on.

      Indeed, a growing body of research is documenting how experience with language radically restructures the brain. People who were deprived of access to language as children (e.g., deaf individuals without access to speakers of sign languages) show patterns of neural connectivity that are radically different from those with early language exposure and are cognitively different from peers who had early language access. The later in life that first exposure to language occurs, the more pronounced and cemented the consequences. Further, speakers of different languages develop different cognitive skills and predispositions, as shaped by the structures and patterns of their languages. Experience with languages in different modalities (e.g., spoken versus signed) also develops predictable differences in cognitive abilities outside the boundaries of language. For example, speakers of sign languages develop different visuospatial attention skills than those who only use spoken language. Exposure to written language also restructures the brain, even when acquired late in life. Even seemingly surface properties, such as writing direction (left-to-right or right-to-left), have profound consequences for how people attend to, imagine, and organize information.

      The normal human brain that is the subject of study in neuroscience is a “language” brain. It has come to be the way it is through a personal history of language use within an individual’s lifetime. It also actively and dynamically uses linguistic resources (the categories, constructions, and distinctions available in language) as it processes incoming information from across the senses.

      Put simply, one cannot understand the human brain without understanding the contributions of language, both in the moment ofthinking and as a formative force during earlier learning and experience. When we study language, we are getting a peek at the very essence of human nature. Languages—these deeply structured cultural objects that we inherit from prior generations—work alongside our biological inheritance to make human brains what they are.

Coming of Age in the Animal Kingdom

[These excerpts are from an article by Linda Wilbrecht in the 27 September 2019 issue of Science.]

      An enduring story plot finds a youth suddenly alone in the world, struggling to find shelter from the elements, safety from predators, food, and new friends. These struggles usually involve some tough lessons but ultimately lead to knowledge, a new identity, self-reliance, and maybe even love. In Wildhood, this theme comes to exhilarating life as evolutionary biologist Barbara Natterson-Horowitz and science writer Kathryn Bowers describe the challenges faced by adolescent animals.

      The book relates the coming-of-age stories of a king penguin named Ursula, a hyena named Shrink, a humpback whale named Salt, and a European wolf named Slavc—all adolescent animals and research subjects followed by field biologists. We meet Ursula as she leaves her parents for the first time and jumps daringly into the icy sea filled with hungry leopard seals. We watch Shrink, who has an unusual knack for social situations, rise in the stark hierarchy of hyenas. We observe Salt develop desire and navigate courtship and consent among “rowdy groups” of bull whales and follow Slave as he sets out on an epic journey across the Alps in winter.

      In addition to these four stories, the authors include smaller anecdotes and gleanings from observations of other wild animals and human youth, all members of the “horizontal tribe of adolescents.” On a single page, you might meet bald eagles, flying foxes, salamanders, and fruit flies. Collectively, the stories illustrate four competencies: how to stay safe, how to live with others, how to communicate sexually, and how to leave the nest and care for oneself.

      Learning to stay safe involves taking risks and getting close to danger. The first pages of the book introduce readers to a group of adolescent sea otters in California that swim in the “Triangle of Death,” where great white sharks lurk and there are few places to hide. In choosing to swim where no others dare, those that survive learn to identify and evade predators. Additional examples—from clueless farmed salmon to human teenagers at scary movies—emphasize the fact that some level of risk-seeking behavior may make individuals safer, more informed adults….

      Some animals, like some kids, never leave home. In the animal kingdom, this can be a rather good strategy. Male western bluebirds that stick around for the winter sometimes inherit their parents' territory, and there are red squirrel mothers who fill up caches for their young and then move out, leaving behind a proven territory for their lucky offspring.

      There are special considerations for social animals that live in groups. A parent wondering why their teenager is obsessed with status and social media will likely be interested to learn that “status is like gravity,” helping social creatures from chickens to hyenas to humans gain greater access to food, territory, and other resources. The authors point out that in the natural world, status assessments may be limited by space and season, but for modern youth, the internet may create status assessment overload.

      Wildhood’s chapters on sexual development call for more education on courtship, relationships, and consent and less focus on the sex act itself. They explain that moths, songbirds, and whales first must practice courtship rituals and need to learn to correctly read the cues made by others.

      …By laying out the adolescent experience of so many species in rich detail, the authors normalize and celebrate the beauty and complexity of our own species’s journey into the big wide world.

The Education of an Educator

[These excerpts are from an article by Roshini Ramachandran in the 27 September 2019 issue of Science.]

      …I also knew that the course had a reputation for doling out few A’s. This was a source of stress for premed students in particular, who feared that a low grade in organic chemistry would keep them from getting into medical school. I had no idea that my exam could elicit a full-blown panic attack, though….

      The following day, I was scheduled to lecture to the same class. I knew that I had to address what had happened during the midterm. I didn’t want to infringe on the student's privacy by mentioning her. So, I started by saying: “I want to take some time today to talk about something important. How many of you think that this is a weed-out course?” Half of my students raised their hands gingerly. “I’m sorry to hear that,” I continued. “I want you all to know that I do not consider any of you to be weeds; you all deserve to be here.”

      I flashed a slide of flowers in various shapes and hues—a stark contrast from the chemical structures I'd shown in past lectures. I smiled at my students and said: “I think of you as flowers—different flowers with different needs. You may not bloom at the same time, but you will bloom! You may not do well in a midterm exam, but you will learn from your mistakes and do better on the final exam. I believe this. I believe in you.”

      From that point on, my office hours were packed. Previously, only a few top-performing students had come, but the new batch included students who were struggling as well as those who were first-generation college attendees. Some asked about lecture topics and study strategies; others opened up about personal issues—family health problems, impostor syndrome, depression—that they’d been struggling with. I was amazed that a simple, frank discussion in lecture could make such a difference.

      We educators shouldn’t need a crisis to remind us of our students’ emotional needs. But it took a crisis to transform my approach to teaching. I now make a point of talking about mental health at the outset of every course, giving the students my “flower” speech and mentioning places where they can go for extra support. Before exams, I ask my students to use digital clickers to rate their current mental health and I share the results on-screen, which helps students realize that they're not alone in feeling stressed.

      Finally, I do my best to learn my students’ names. This may seem like a small thing, and it’s challenging in such a large class. But I’ve found that they feel valued—and are more likely to ask me for help—when I put in the effort to recognize them as unique individuals.

Minefield

[These excerpts are from an article by Warren Cornwall in the 27 September 2019 issue of Science.]

      …Bristol Bay consistently sees tens of millions of returning fish, year after year, making it one of the world’s most productive and lucrative salmon fisheries….A mining company wants to extract copper and gold from a massive ore deposit beneath headwaters of two of Bristol Bay’s main salmon rivers. The Pebble Mine could become one of the world's biggest mineral producers, with an open pit nearly as deep as the Grand Canyon and vast infrastructure and waste piles that would stretch for kilometers.

      Opponents of the project, including Native Alaskan, fishing, and environmental groups, have long argued that the mine’s short-term economic benefits would pale in comparison with the long-term risks to Bristol Bay’s salmon runs, including toxic runoff and habitat destruction. Critics have seized on Schindler's science to help make their case, and in 2014 the findings helped persuade then-President Barack Obama’s administration to move to block the mine. But this year President Donald Trump’s administration signaled it might allow the project as part of its efforts to encourage development.

      …Over the past 4 decades, an average of nearly 40 million salmon have returned to the bay each year. (By comparison, it's a good year when 3.5 million fish return to the Columbia River, the largest salmon river in the lower 48 states.) Most are sockeye, which spend their first year or two in freshwater and then head out to the North Pacific Ocean for 1 to 3 years before returning to reproduce. The deluge of fish draws more than 2000 commercial fishing boats, fueling a salmon economy worth about $300 million a year. Bristol Bay accounts for nearly half of all sockeye caught in the world….

      If Northern Dynasty Minerals, based in Vancouver, Canada, has its way, a piece of the landscape will be transformed. Several versions of the Pebble Mine have emerged in company proposals and studies done by the Environmental Protection Agency (EPA) in Washington, D.C. Under the most expansive scenarios, it would become the world’s biggest gold producer and one of the top 10 copper mines, yielding up to 24 million tons of copper and 1400 tons of gold over its lifetime. An open pit covering 18 square kilometers would be the largest in North America. Infrastructure would include 195 kilometers of road and humanmade lakes full of toxic mine wastes covering an area nearly the size of New York City’s Manhattan island. It could employ more than 1000 people during regular operations and bring in revenues of $300 billion to $500 billion, according to an EPA study.

      Even that massive operation would be dwarfed by the immense Alaskan landscape. Constructing a smaller version of the mine, for example, would touch on streams draining less than 1% of the land surrounding Bristol Bay, according to the U.S. Army Corps of Engineers.

      But mine opponents fear that once roads and other infrastructure are built, the mine could expand and surrounding mining claims could become viable. And Schindler notes that even a single mine could have big impacts. It would straddle two of Bristol Bay’s watersheds. One drains into Lake IIiamna, Alaska’s biggest, which has produced about one-fifth of the bay’s sockeye salmon over the past 2 decades. The other feeds the Nushagak River, which has produced an average of 6.5% of sockeye populations….

      In 2014, Obama’s EPA took the unusual step of announcing it planned to veto Northern Dynasty's expected application for a federal permit needed to fill wetlands and streams, effectively killing the project. The agency pointed to a host of hazards: tens of kilometers of streams and tributaries destroyed, disruption of water flows, and the risk of stream pollution from copper—a potent aquatic poison—stirred up by mining. If a tailings dam failed in the earthquake-prone region, contaminated waste could pour down a nearby river. Even a smaller version of the mine, the agency declared, “jeopardizes the long-term health and sustainability of the Bristol Bay ecosystem.”

      The portfolio effect underpinned those concerns. Though the mine would touch only a small percentage of the overall system, and even a catastrophic failure wouldn’t reach most watersheds, agency scientists feared that losing even some pieces could undermine the whole system. What would happen in years when salmon populations in other streams went bust, and damaged streams weren't there to take Lup the slack?

      …Trump’s election, however, as well as the later election of a pro-mining Alaskan governor, has given the Pebble Mine new life. In 2017, the company proposed a mine with a smaller footprint and more environmental safeguards, which it says would address EPA's concerns. For example, the company says that after 2 decades of mining it would dump the tailings into the pit and cover them with water, eliminating the need for storage ponds.

      Several federal agencies, now led by Trump appointees, have greeted the new plan more warmly. In February; the Army Corps, which controls federal wetlands permits, issued a draft environmental impact statement, finding the project would cause no population-level damage to salmon. In July, EPA withdrew its earlier veto proposal, saying its previous conclusion was outdated. Trump administration officials have suggested they hope to issue a final decision on the mine’s wetland permits by mid-2020. Whatever the timeline, any decision is certain to be challenged in court.

      …The company’s newest proposal calls for mining roughly 15% of the ore deposit and not reaching the richest veins….many critics, including Schindler, suspect the current plan is just a first phase, downsized to pass regulatory muster while opening the door to a much bigger future mine—with much greater environmental impacts.

      Federal wildlife agencies have expressed similar concerns. The National Marine Fisheries Service and the Department of the Interior (DOI) have warned that the Army Corps has largely ignored the possibility of a bigger mine and understated or failed to consider risks to salmon. DOI officials wrote that the draft study was “so inadequate that it precludes meaningful analysis….”

Warming Transforms the Oceans and Poles

[These excerpts are from an article by Paul Voosen in the 27 September 2019 issue of Science.]

      Water, liquid and frozen, occupies most of Earth’s surface, with oceans covering two-thirds of it and ice another 10th. All is being transformed by climate change, posing greater threats to life and human society than scientists had realized, according to a special assessment of climate science focused on oceans and ice released this week by the United Nations.

      The report, from the Intergovernmental Panel on Climate Change (IPCC), comes during a week when the world is fixated on what many now call the climate crisis. The planet has already warmed 1°C since preindustrial times, and July was the hottest month in the modern record….

      …the watery parts of the planet are already entering a new state. After 0.2 meters of sea level rise since the late 1800s, some coastal cities flood routinely during high tides. With the Arctic warming at double the global rate, sea ice is in rapid decline, causing severe disruption to Indigenous communities and wildlife. Permafrost is thawing, undermining infrastructure and releasing uncertain amounts of buried carbon. The ocean is warming at all depths, and heat waves increasingly strike its inhabitants….

      Compared with the last U.N. climate report, in 2014, the new assessment paints a grimmer picture of the future. By 2100, within the lifetime of those striking children, global sea level would likely rise by up to 1.1 meters if greenhouse gas emissions continue unabated; the last IPCC report had set the upper limit at 0.98 meters. Even with steep cuts in fossil fuel burning, the oceans will rise between 0.29 and 0.59 meters, the report adds….

      Without action, rare, catastrophic storm surges will become common within 30 years….Rising waters pose a particular threat to small island nations near the equator, where storms are rare and sea level typically varies little, allowing infrastructure to be built close to the ocean. There are also examples of resilience: Shanghai, China, for example, pumped water back into its underground aquifers to counteract subsidence that had made the city more vulnerable to sea level rise—a challenge also facing many other coastal cities.

      The ocean’s structure and composition are changing in less obvious ways….Over the past 15 years, an array of 4000 autonomous floats has documented steady, continuous warming extending to the ocean depths. This warming makes surface waters less dense and more buoyant and reduces mixing with deeper layers. Fewer nutrients well up from the deep, and less oxygen mixes downward….

      Across the Arctic, the thawing permafrost could amplify climate change by releasing carbon it has held for millennia. But when the impact of those extra emissions will be felt is unclear. Warmer temperatures are causing the Arctic to become greener, and the increasingly luxuriant plants are capturing extra carbon and storing some of it in the soil. At some point, however, the carbon released is likely to overwhelm the carbon absorbed….

      Like all IPCC reports, this week’s assessment reflects only science submitted for publication, which means it is already out of date….

      Perhaps the biggest struggle for IPCC scientists has been assessing the speed of future sea level rise, which hinges largely on the fate of the West Antarctic Ice Sheet. The odds are low that the ice sheet will collapse this century, which would eventually drive meters of extra sea level rise. But in recent years, several of its vital buttressing glaciers have slid toward the sea, and an international team is now studying its most at-risk glacier, Thwaites. Scientists continue to debate whether an unstoppable collapse has already begun….

      It’s one more reason for the world to make big cuts in carbon emissions, right away….

Fly Less to Convey Urgency

[These excerpts are from an editorial by Peter Kalmus in the 27 September 2019 issue of Science.]

      Last week, just days before the United Nations Climate Summit in New York, students across the globe protested in response to inaction over the greatest threat to humanity. Climate breakdown exists on a continuum of harm—it will get worse the hotter the planet gets. Limiting the catastrophe requires an effort at all scales of society.

      Climate breakdown can't be fully understood without data, sophisticated analysis, and models. These tools of science are needed, for example, to formally attribute disasters such as hurricanes, floods, and wildfires to human-caused global heating, or to understand what humanity will face on a hotter planet. It is understandably difficult for the public and policy-makers to directly consult the peer-reviewed literature and respond appropriately. This suggests that scientists have an ethical responsibility to alert the public.

      …Now, the climate crisis is so severe that many scientists are looking for other ways to persuade society to accelerate climate action.

      …When a scientist speaks only in the language of facts, the message gets through mostly to other scientists. Those without scientific training tend to look for emotional cues and reasons to trust scientists; without them, they may underestimate a scientist’s level of concern. Scientists can bridge this gap by also speaking from the perspective of a concerned citizen and by taking personal actions that the public can relate to….

      Hour for hour, it’s hard to find a better way to heat the planet. Flying coach burns 0.2 to 0.3 kg of carbon dioxide (CO2) worth of jet fuel per passenger mile, roughly equivalent to driving (alone) a gasoline car that gets 40 to 50 miles per gallon. Add three passengers, and the car emissions go down to 0.06 kg of CO2 per passenger mile. Short-term radiative forcing from ozone production, contrails, and cirrus cloud formation further increases the climate impact of planes. Although aviation accounts for only 2% of global carbon emissions, flying less could be a powerful lever for cultural shift. In some sectors, including academia, flying reflects freedom and even success. If scientists fly less, it could communicate climate urgency more effectively.

      Frequent flying is often justified by carbon offsets or by invoking the possibility of future carbon-free flight. However, battery energy densities are still an order of magnitude too low to support long-distance fights, and there is not enough biofuel to support aviation at the scale needed. Offset companies cannot guarantee that offsetting practices will permanently sequester an equivalent amount of carbon and even if they could, people should be embracing those practices anyway, without negating them with flight emissions.

      Not all scientists can eliminate flying, but it’s time for the scientific community to find creative alternatives to the fly-in meeting. These could include regional meeting hubs connected by remote technology, asynchronous on-line-only conferences, or virtual reality conferences. Such efforts could lead to co-benefits such as smaller, specialized meetings and increased participation by students and low-income nations. Flying is tied to the scientific profession and flying less is an action that can be taken as a community, amplifying individual actions through the authority of its institutions and professional societies and sending a clear message of climate urgency to the public.

Low-Carbon Air Travel Is Coming

[This excerpt is from an article by Wade Roush in the October 2019 issue of Scientific American.]

      …An online calculator showed that the flights I take every year put a yikes-inducing 15 metric tons of carbon into the atmosphere—equivalent to the overall annual carbon emissions of three average earthlings. So I signed up with a company called terrapass to buy offsets for 12 tons of carbon a year, at about $10 per month. Terrapass uses that money to do commendable things such as capturing methane from landfills, building wind farms and preserving carbon-sequestering forests.

      I’m not under the illusion that these projects cleanse my sins as an air traveler. At best., they simply prevent the release of an equal quantity of greenhouse gases down the road. The offsets do help me and other consumers feel less guilty about flying—which is probably why airlines such as United and Delta now offer them as part of the booking process. And on a larger scale, there’s evidence that offsets function as a kind of self-imposed carbon tax, encouraging people who buy them to keep their own energy use in check. But the reality is that voluntary offsets will never come close to matching aviation emissions, which account for 2 percent of overall human-induced carbon emissions.

      For one thing, any benefit from offsets is likely to be overwhelmed by growing demand for air travel. According to a recent report from Airbus, about 4.0 percent of the world population is now middle class, and by 2037 this group will have mushroomed to more than 50 percent, or some five billion people—“all in the pool of regular or potential new” passengers.

      And buying an offset isn’t a guarantee that your flight emissions will actually be, you know, offset, since it’s difficult to prove that carbon-avoidance projects wouldn’t have happened anyway or that the neutralized carbon will never be released in the future….

      Regardless of their relation to consumer trends, offsets aren’t a solution to the underlying physics problem in aviation, which is that today’s long-haul passenger jets can’t take off without burning a high-energy-content fuel such as kerosene. That’s why OPEC is confident that worldwide demand for jet fuel will reach nine million barrels a day by 2040, up from 6.3 million in 2017.

      Short of drastic rationing of air travel, the only long-term solution for aviation’s carbon woes is electrification. Biofuels from feedstocks such as sugarcane, algae and household garbage, which burn more cleanly than fossil fuels, could help in the short run—United has been mixing them into traditional jet fuel since 2016. But the real hope lies in projects such as E-Fan X, a test plane from Airbus, Rolls-Royce and Siemens in which one of the four gas-powered turbofans is replaced by an electric motor. The partners see the project as a step toward meeting the European Union's ambitious “Flightpath 2050” goal of reducing aviation’s carbon dioxide emissions by 75 percent by 2050.

      Start-ups are getting into the game, too: Seattle's Zunum Aero, backed by Boeing and JetBlue, is designing a regional jet with batteries in the wings and fans powered with a “hybrid to electric” power train. To be light enough for flight, aviation batteries will need a specific energy—a measure of how much power a battery contains for its weight—far beyond that of today’s lithium-ion battery packs. So, for the time being, Zunum’s power train will run partly on jet fuel.

      The improvements in batteries and motors needed to fully electrify the skies could take “the next few decades,” Zunum co-founder B. Matthew Knapp acknowledged in a recent Nature Sustainability op-ed. Meanwhile buying offsets is a substitute that both feels good and does good. Just don't assume that it will keep our climate-spoiling travel habits aloft forever.

Venomous Secrets

[This excerpt is from an article by Rachel Crowell in the October 2019 issue of Scientific American.]

      We rarely think of scorpions as beneficial. But researchers have isolated two new compounds in the arachnids’ venom that show promise for treating staph infections and drug-resistant tuberculosis.

      Scorpion venom is beyond expensive: harvesting a milliliter would cost about $10,300….He estimates that “milking” venom from one scorpion can yield only a few thousandths of a milliliter at a time at most, and it takes two or more weeks for an individual’s supplies to replenish. The substance can still be worth studying, however. Some of its constituent compounds have intriguing medicinal properties and can be synthesized more cheaply in the laboratory.

      Researchers…milked scorpions of the eastern Mexican species Diplocentrus melici, whose venom had never been studied before. They separated its components and tested some on Staphylococcus aureus, Escherichia coli and Mycobacterium tuberculosis bacteria. Two of these components—one of which happens to be red when isolated and the other blue—killed staph and TB microorganisms, suggesting their potential as antibiotics.

      The researchers sent small samples of the isolated compounds to…Stanford to determine the substances’ compositions and molecular structures. The group then chemically synthesized the compounds….

      There pathologists tested the synthesized substances in mice infected with tuberculosis and on human tissue samples hosting staph bacteria. The red compound proved more effective at killing staph, and the blue one worked better on TB—including a drug-resistant strain—without damaging the lining of the mice’s lungs.

      …the study’s approach seems promising. But she cautions that the compounds still need to be tested in larger animals—and they could also be challenging to synthesize on the scales required for testing in humans.

Going the Distance

[This excerpt is from an article by Jennifer Leman in the October 2019 issue of Scientific American.]

      After poison frog tadpoles hatch from their eggs in the leaf litter, they wriggle onto the backs of their patiently waiting fathers, who piggyback them to water. Scientists studying the candy-colored amphibians, sometimes called poison dart frogs, in the Amazon rain forest recently discovered that frog dads often skip close-by ponds in favor of something more distant—a move that expends precious ener-gy. Sometimes they traveled as far as 400 meters….

      Three-striped poison frogs traveled farthest, traversing an average distance of roughly 215 meters—when the nearest available pool was on average only 52 meters away from their home territory. Dyeing dart frogs traveled approximately 39 meters on average, hopping past ponds an average distance of 19 meters away. Two frogs even left the forest's shelter to deposit their tadpoles in flooded pastures.

      Despite the energy cost and higher risk of meeting predators, dropping young tadpoles in faraway pools may offer evolutionary benefits such as decreased risk of inbreeding and less competition for resources….But it is difficult to say what exactly motivates the frogs themselves to go farther….

Disappearing Bodies

[This excerpt is from an article by Bahar Gholipour in the October 2019 issue of Scientific American.]

      In 1231 Frederick II, the Holy Roman Emperor who ruled over much of Europe, issued a decree requiring schools that trained doctors to hold a human body dissection once every fiveyears. It was a slow debut for what would become a cornerstone of medical education. During the Renaissance, cadaver dissections helped scientists and artists gain a hands-on understanding of human anatomy. Today they are an essential experience for first-year medical students, a time-honored initiation into the secrets of our flesh.

      Now, nearly a millennium after its measured introduction, cadaver dissection may have begun an equally slow exit. This year a few U.S. medical schools will offer their anatomy curriculum without any cadavers. Instead their students will probe the human body using three-dimensional renderings in virtual reality, combined with physical replicas of the organs and real patient medical images such as ultrasound and CT scans.

      The program developers hope technology can improve on some of the limitations of traditional approaches. It takes a long time to dissect cadavers, and some body parts are so inaccessible that they may be destroyed in the process. Plus, the textures and colors of an embalmed cadaver’s organs do not match those of a living body, and donated bodies tend to be old and diseased….

      …When he tried to access organs in living patients, looking at imaging results or footage from tiny inserted cameras, he found the inside of human bodies did not match what he had seen in cadavers. “They’re totally different,” Young says. “The embalmed cadaver has a very flat, cornpressed organ presentation. The colors are not the vibrant colors of a living human.” The difference can distract from learning….

      Virtual anatomy tools, in contrast, provide a more faithful view of living organs, helping students form a foundational understanding of the body’s structures….By donning VR headsets or augmented-reality goggles, which show digital imagery super-imposed on the real world, students can examine an organ from all angles. They can connect structure with function by watching a beating heart or moving joints. They can also select views that add other organs or the entire circulatory and nervous systems to better see relations among structures….

      Adopting high-tech alternatives makes sense for brand-new medical programs that have neither the tradition nor the facilities for cadaver dissection, but even some existing ones are adopting digital tools to supplement their anatomy courses….

      Besides the educational advantages, going cadaverless is an economic decision for new programs. It costs several million dollars to build a cadaver laboratory, which requires a lot of space, as well as safety measures that meet legal regulations. And although cadavers are donated, medical schools still pay for preparation, maintenance and, eventually, burial. These costs are an even bigger challenge for schools in less wealthy nations….

      Cadaverless anatomy education has its drawbacks. It may be hard to develop a perception of depth in a virtual body, and students will miss out on seeing bodies’ natural anatomical variations…. Students may also lose the emotional, even philosophical impact of working with a cadaver, commonly seen as a doctor’s first patient….

      Another open question is whether students learn as well using the digital tools. Educators’ studies are probing whether replacing old techniques with new technology will actually improve, and not harm, the quality of their students’ education. Their results, if positive, may encourage more schools to convert….

Closing the Skills Gap

[This excerpt is from an article by Rick Lazio and Harold Ford in the October 2019 issue of Scientific American.]

      …Given these statistics and the rapid adoption of new technology, it is clear that STEM skills will be critical in the new tech economy. If left unaddressed, the shortage of STEM workers will have long-term and extremely consequential ramifications such as stagnated economic growth. This situation leaves our country at considerable risk of losing high-paying jobs to other nations.

      …The U.S. is falling behind other countries in achievement in STEM areas for a variety of reasons, including a lack of consistent exposure to the relevant subjects for young students—particularly minority students. Although both the Obama and Trump administrations emphasized the importance of STEM education, with the U.S. Department of Education investing $279 million in STEM discretionary grant funds in 2018, more can be done to make the system consistent for all of America's K-12 students.

      In 2015, according to the Pew Research Center, the U.S. placed 38th in math and 24th in science out of 71 participating nations in the Program for International Student Assessment (PISA), one of the largest tests to measure reading, math and science literacy. Also, the World Economic Forum reported that in 2013, 40 percent of Chinese graduates completed a degree in STEM—more than double the percentage of Americans. These numbers clearly point to a disturbing trend in our country’s ability to funnel technical labor into the workforce and remain competitive on an international scale.

      So how do we reverse this alarming trend? First, we must make STEM curricula central to primary and secondary school standards and encourage students to pursue STEM careers. Second, we must rethink our approach to education. Learning should be a lifelong endeavor, not just a K-12 priority. Businesses laying the groundwork for disruptive operational change via automation, Al and other means must also prepare to retrain their workers and give them the technical skills needed for the company’s next generation of jobs.

      Finally, immigration reform can ensure that those who enter the U.S. for a STEM education receive incentives to stay and contribute to our economy….

Cleaning up Plastic Pollution in Africa

[These excerpts are from an article by Bilikiss Adebiyi-Abiola, Solomon Assefa, Kareem Sheikhand Jeannette M. Garcia in the 20 September 2019 issue of Science.]

      …Over 416 billion plastic bags per month are used globally. In Africa, they litter roads, rivers, boreholes, and sewage systems. In many African countries, increasing plastic pollution has motivated policy-makers to enact legislation to protect the environment from further contamination. Currently, Africa has the highest percentage of countries (-46%) with plastic bans. For example, in 2008, Rwanda took the global lead in banning nonbiodegradable polyethylene bags. The law prohibits the manufacture, use, import, and sale of nonbiodegradable bags that fall outside its sustainability criteria, and violations are punishable by high fines or jail time. It is strictly enforced at airports and other port entries by agents from the Rwanda Environment Management Authority. Tax incentives in Rwanda are motivating plastic bag manufacturers to consider recycling as a business opportunity. The policy has led to local production of sustainable bags made from local materials, alleviating fears about negative impact on small businesses, jobs, and foreign direct investment.

      Some African countries are following Rwanda’s lead, albeit with less effective law enforcement. Tanzania is in the second phase of its plastic ban, and Kenya is following a gradual path by taxing plastic bags. Although Kenya implemented a plastic bag ban in 2017, punishable with fines and jail time, enforcement has been difficult. The tax has decreased consumer demand for single-use plastic shopping bags and increased the use of reusable alternatives. Kenya also is incentivizing community-led collection that is turning plastics into mattresses and eco-friendly asphalt, bricks, fencing posts, school bags, and shoes….

      Many of the programs in Africa that limit the production of new, nonbiodegradable plastics have occurred in the last 4 years. Thus, there are few data about the efficacy of these programs and technological efforts to tackle plastic waste, but the engagement and public responses are encouraging. Although efforts to limit plastic use may reduce the introduction of new plastics into the environment, the need to address plastic pollution already present in Africa still remains.

      Plastics pollution prevention in Africa is tightly coupled to the economics of recycling. Globally, about 90% of all waste is dumped or burned in low-income countries. In high-income regions, waste management is more regulated and recycling rates are higher….In African urban areas where formal waste collection and sorting infrastructure are available (primarily in city centers), new technologies for vehicle-based waste collection can improve collection efficiency. In one example, about 2500 metric tons of waste is generated daily in Nairobi, Kenya, but only -50% of the garbage is collected….

      The African population is expected to grow to 2.5 billion by 2050. Its most populous city, Lagos, Nigeria, is projected to grow to 32.6 million by that time. In 2014, 12,000 tons of waste was generated daily by Lagos citizens, 15% of which was plastic. The overburdened Lagos municipality collected only about 40% of this total generated waste. Once collected, waste is taken to dumpsites and plastics are recycled manually in the budding recycling sector. Despite health and safety risks involved in this work, informal and formal waste reclaimers are a key component of waste management, not only in Lagos but across Africa. For example, waste workers are responsible for recycling 80 to 90% of the plastic packaging that is recycled in South Africa.

      Plastic recycling in Africa has focused on commodity plastics and is mainly centered on first-level processing (such as baling and shredding). Such processed plastic is then sold and exported to Asia, where it is down-cycled to products such as pillow stuffing. Although this extends the lifetime of materials, the process creates downcycled products that can no longer be recycled….

      Collecting enough plastic waste to feed recycling plants is a continuous struggle anywhere in Africa. Formal collection infrastructure is still being developed across municipalities. The absence of policies to promote plastic recycling at-scale, coupled with limited road networks for general waste collection, little public awareness of plastic recycling, and an unstable global plastic recycling market, has stunted the adoption of recycling in several African cities….

      The rapid adoption of information technologies at various points along the plastic waste recycling chain can facilitate the realization of a closed-loop plastic waste ecosystem. Regional factors, such as government regulations and consumer motivation to improve African quality of life, play a critical role in the adoption of technologies to tackle plastic pollution in an environment that otherwise lacks a plastics recycling framework….

Renewable Bonds

[These excerpts are from an article by Robert F. Service in the 20 September 2019 issue of Science.]

      Black, gooey, greasy oil is the starting material for more than just transportation fuel. It's also the source of dozens of petrochemicals that companies transform into versatile and valued materials for modem life: gleaming paints, tough and moldable plastics, pesticides, and detergents. Industrial processes produce something like beauty out of the ooze. By breaking the hydrocarbons in oil and natural gas into simpler compounds and then assembling those building blocks, scientists long ago learned to construct molecules of exquisite complexity.

      Fossil fuels aren’t just the feedstock for those reactions; they also provide the heat and pressure that drive them. As a result, industrial chemistry’s use of petroleum accounts for 14% of all greenhouse gas emissions. Now, growing numbers of scientists and, more important, companies think the same final compounds could be made by harnessing renewable energy instead of digging up and rearranging hydrocarbons and spewing waste carbon dioxide (CO2) into the air. First, renewable electricity would split abundant molecules such as CO2, water, oxygen (O2), and nitrogen into reactive fragments. Then, more renewable electricity would help stitch those chemical pieces together to create the products that modern society relies on and is unlikely to give up….

      Chemists in academia, at startups, and even at industrial giants are testing processes—even prototype plants—that use solar and wind energy, plus air and water, as feedstocks….The company, located in a low-slung office park in Berkeley, has designed a washing machine-size device that uses electricity to i.,, v convert water and CO2 from the air into fuels and other molecules….

      Changing the lifeblood of industrial chemistry from fossil fuels to renewable electricity “will not happen in 1 to 2 years,” says Maximilian Fleischer, chief expert in energy technology at Siemens. Renewable energy is still too scarce and intermittent for now However, he adds, “It’s a general trend that is accepted by everybody” in the chemical industry.

      A sharp rise in supplies of solar, wind, and other forms of renewable electricity lies behind the trend. In 2018, the world surpassed 1 terawatt (TW) of installed solar and wind capacity. The second TW is expected by mid-2023, at just half the cost of the first, and the pace is likely to accelerate. One recent analysis suggests lower prices for renewable generation could prompt the development of 30 to 70 1W of solar energy capacity alone by 2050, enough to cover a majority of global energy needs….According to the National Renewable Energy Laboratory, the cost of utility-scale solar power should drop by 50% by 2050 and the cost of wind power by 30%.

      That surge in renewables has already led to brief periods when electricity supplies exceed demand, such as midday in sunny Southern California. The result is dramatic price drops. At times, utilities even pay customers to take electricity so that excess supply doesn’t melt transmission lines….

      But even if the heat comes from electricity reactions such as those that generate fuel from methane still emit waste CO2. Chemists want to go further, harnessing electrons not just as a source of heat, but as a direct input to the reactions. Industrial chemists already use electricity to smelt aluminum from bauxite ore and generate chlorine from salt—electron-adding reactions for which electrically driven chemistry is ideally suited. But as with H2, most commodity chemicals are made from fossil fuels, transformed with heat and pressure generated by more fossil fuels.

      Giving up those fuels doesn’t involve chemical magic. Key industrial chemicals such as carbon monoxide (CO) and ethylene can already be made by adding electrons to abundant starting materials such as CO2 and water, if efficiency is no object. The trick is to do so economically.

      That process requires a cheap source of renewable electricity….They found that electrosynthesis would be competitive for producing chemical staples such as CO, H2, ethanol, and ethylene if electricity cost 4 cents per kilowatt hour (kWh) or less—and if the conversion of electrical energy to energy stored in chemical bonds was at least 60% efficient.

      If electricity’s cost fell further, more compounds would be within reach….an electricity price of 2 cents/ kWh, synthesizing formic acid, ethylene glycol, and propanol would all be feasible….

      Kammen notes that several utility-scale solar and wind projects already meet one benchmark, delivering power at or below 4 cents/kWh, and the cost of renewables continues to decline….But reaching 60% conversion efficiency of electrical to chemical energy is a bigger challenge, and that’s where researchers are focusing their efforts.

      The simplest processes, those that make H2 and CO, are already reaching that second benchmark….

      …Last month, in Dresden, Germany, a company called Sunfire completed a test run of a high-temperature electrolysis reactor, known as a solid-oxide fuel cell, that promises even higher efficiency than PEM electrolyzers….Because the plant works at high temperatures, the water- and CO2-splitting reactions convert electrical energy to chemical bonds at nearly 80% efficiency, the company says….

      But as chemists develop new reactors and find ever-more-charmed combinations of catalysts—and as renewable energy continues to surge—the plants that churn out chemical staples will inevitably become more like the green variety, fully sustained by sun, air, and water.

400 Years and (Re)counting

[This editorial by Shirley M. Malcolm is in the 20 September 2019 issue of Science.]

      Over centuries of slavery in America, systematic structures were erected to present enslaved people as “the other”—a race apart and less than human—as a way to justify the institution and forestall discussions of its inhumanity and the moral imperative to dismantle it. These efforts included invoking science, as objective arbiter, in support of these viewpoints. Some theories of human origins, for example, espoused by great names of science, reflected attempts to bolster constructs of racial inferiority rather than to advance science. But they did their damage, and we live with their fallout even today. How many of the current challenges in diversifying science are part of this legacy: lack of investment in education; belief in innate capacity to do science (or not); exclusionary teaching practices; tolerance of classroom microaggressions; implicit bias in hiring, and in assessing and valuing work?

      This year marks the 400th anniversary of slavery in America, provoking scholarly retrospectives that have considered how central a role the concept of race has played in the course of human affairs, including in science. The ground that has been stirred offers an opportunity for soul searching and reflection, not only about science’s past but perhaps, more importantly, about its present and future. Articles have appeared, including in Science, revealing some of the scientific and medical advances associated with slavery, such as the natural history collections derived from the transatlantic slave trade where Africans were shipped to the Americas as enslaved people whose labors became a driving force of the economies of the European colonies, or the cruel experimentation on enslaved women in the history of gynecology.

      It is difficult to tell these stories or to read them, especially for those who are both descendants of these enslaved people and members of the science community. The marginalization continues today, long after the legal end of the institution. Outcomes manifest themselves as statistics documenting inequality and limited opportunity within and beyond the United States, such that, in the United Kingdom in 2018, blacks and other minorities comprised less than 1% of professors in higher education institutions.

      But the lens of science has also provided a powerful tool to help reframe the narrative of exclusion: race as social construct rather than biological reality; stereotype threat as self-fulfilling and reversible; lack of opportunity rather than lack of capacity. Sadly, the damage continues. How much of this legacy is represented (through the inherited trauma of epigenetic changes) in health disparities—poor disease outcomes; differential maternal and infant mortality for blacks and whites, independent of socioeconomic levels—or in wealth and income inequality? It is time to use scholarship to uncover the deeply rooted structures that science helped reinforce.

      Even while acknowledging blanket complicity, beyond science there is a powerful social infrastructure in laws and tolerance of behaviors that holds inequalities in place, and possibly more on the horizon such as artificial intelligence which, as a tool that relies on historical information, promises to deliver old discriminatory wine in new algorithmic bottles, cloaked in the black boxes of proprietary models.

      Continued inequality should not be an inevitable legacy of America’s past. Diverse perspectives and convergent scholarship can be applied to build an understanding from the history of biological and political theories, and from the social and cultural traditions that fuel today's system of inequality. Even if the political will should arise to take on the grand challenge of creating a system of opportunity for all, different institutional structures would be needed to begin the hard work: diverse participants, perspectives, fields, and practices; un-siloed, solution-focused, nonpartisan discussions; and governance by a search for truth and reconciliation. The United States needs a map that points the way to unpacking and dismantling the infrastructure of social inequality that was unleashed when slavers docked in Virginia 400 years ago.

Tackling the Toughest Tech

[These excerpts are from an article by Wade Roush in the April 2020 issue of Scientifi American.]

      Some global crises, such as climate change, are too big to overcome through individual action or even through government-level policy change. To survive this century, we are also going to need some huge science and engineering breakthroughs—especially in areas such as energy and transportation. Unfortunately, the systems we have built to encourage innovation are in a dismal state.

      Federal investment in R&D as a share of the overall economy is lower than at any point in the past 60 years. And venture capital—the industry that is supposed to take risky ideas from government or university laboratories and turn them into valuable businesses—has instead spent the past decade investing in low-stakes tech that helps us order takeout, avoid taxis, swap seines and overpay for desk space. Many of Silicon Valley’s “unicorns” are doing no more to improve the world than their mythical namesakes….

      There is, however, at least one bright spot in the world of tech investing. I got a glimpse of it on a recent visit to The Engine, a for-profit venture firm set up in 2016 by the Massachusetts Institute of Technology. It is designed to fund ambitious ideas in areas it calls “tough tech”: energy, nanotechnology, quantum computing, immunotherapy and other fields where the technical and regulatory challenges are too daunting for most venture capitalists.

      A case in point: Commonwealth Fusion Systems. The Engine-backed start-up has turned a former Radio Shack down the street from M.I.T. into a lab where it tests components for future fusion reactors that could produce nearly inexhaustible, economical, carbon-free energy with vastly less radioactive waste than conventional nukes—an elusive goal that scientists have been trying in vain to accomplish for more than half a century. Chief operating officer Steve Renter says Commonwealth’s “Kitty Hawk moment”—when it proves its demonstration machine can generate more energy than it consumes—could come as soon as 2025….

      Part of what sets The Engine apart is the timescale of its $200-million fund. Limited-partner investors know they might not get their money back for 18 years or more, compared with the eight- to 12-year life of a typical venture fund. Plus, the firm provides lab space and equipment in addition to mentorship and networking. And it welcomes companies that hopscotch across disciplines in ways that might puzzle other investors….

      There are 20 start-ups at The Engine right now, and the firm is renovating an old Polaroid building that will soon hold 100 companies and 800 entrepreneurs. Researchers come to The Engine not because they are trying to make a quick buck but because they have an idea they can't bring alive anywhere else….

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