Over the last 40 years, the number of kids and teens with obesity has skyrocketed worldwide. In 1975, an estimated 5 million girls and 6 million boys were obese. By 2016, those numbers had risen to an estimated 50 million girls and 74 million boys, according to a report published online October 10 in the Lancet. While the increase in childhood obesity has slowed or leveled off in many high-income countries, it continues to grow in other parts of the world, especially in Asia.
Using the body mass index, a ratio of weight to height, of more than 30 million 5- to 19-year-olds, researchers tracked trends from 1975 to 2016 in five weight categories: moderate to severe underweight, mild underweight, healthy weight, overweight and obesity. The researchers defined obesity as having a BMI around 19 or higher for a 5-year-old up to around 30 or higher for a 19-year-old.
Globally, more kids and teens — an estimated 117 million boys and 75 million girls — were moderately or severely underweight in 2016 than were obese. But the total number of obese children is expected to overtake the moderately or severely underweight total by 2022, the researchers say.
The globalization of poor diet and inactivity is part of the problem, says William Dietz, a pediatrician at George Washington University in Washington D.C., who wrote a commentary that accompanies the study. Processed foods and sugary drinks have become widely available around the world. And urbanization, which also increased in the last four decades, tends to reduce physical activity, Dietz says.
While obesity rates for kids and teens have largely leveled off in most wealthy countries, those numbers continue to increase for adults. The findings in children are consistent with evidence showing a drop in the consumption of fast food among children and adults in the United States over the last decade, Dietz says. “Children are going to be much more susceptible to changes in caloric intake than adults.”
Many people may be fuzzy on the details of North America’s colonial history between Columbus’ arrival in 1492 and the Pilgrims’ landing on Plymouth Rock in 1620. But Europeans were actively attempting to colonize North America from the early 16th century onward, even though few colonies survived.
As historian Sam White explains in A Cold Welcome, most early attempts were doomed by fatally incorrect assumptions about geography and climate, poor planning and bad timing. White weaves together evidence of past climates and written historical records in a comprehensive narrative of these failures. One contributing factor: Explorers assumed climates at the same latitude were the same worldwide. But in fact, ocean currents play a huge role in moderating land temperatures, which means Western Europe is warmer and less variable in temperature from season to season than eastern North America at the same latitude.
On top of that, explorations occurred during a time of global cooling known as the Little Ice Age, which stretched from the 13th to early 20th centuries. The height of exploration may have occurred at the peak of cooling: Starting in the late 16th century, a series of volcanic eruptions likely chilled the Northern Hemisphere by as much as 1.8 degrees Celsius below the long-term average, White says.
This cooling gave Europeans an especially distorted impression of their new lands. For instance, not long after Spanish explorer Sebastián Vizcaíno landed in California’s Monterey Bay in December 1602, men’s water jugs froze overnight — an unlikely scenario today. Weather dissuaded Spain from further attempts at colonizing California for over a century. Harsh weather also heightened conflict when underprepared Europeans met Native Americans, whose own resources were stretched thin by unexpectedly bad growing seasons.
A Cold Welcome is organized largely by colonial power, which means findings on climate are repeated in each chapter. But White’s synthesis of climate and history is novel, and readers will see echoes of today’s ignorance about the local consequences of climate change. “Human psychology may be both too quick to grasp at false patterns and yet too slow to let go of familiar expectations,” White writes.
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A proposed form of ice acts like a cross between a solid and a liquid. Now, a new study strengthens the case that the weird state of matter really exists.
Hints of the special phase, called superionic ice, appeared in water ice exposed to high pressures and temperatures, researchers report February 5 in Nature Physics. Although such unusual ice isn’t found naturally on Earth, it might lurk deep inside frozen worlds like Uranus and Neptune (SN Online: 3/5/12). Normal ice is composed of water molecules, each made of an oxygen atom bonded to two hydrogen atoms. As water freezes, those molecules link up to form a solid. But superionic ice is made up of ions, which are atoms with a positive or negative electric charge. Within the material, hydrogen ions flow freely through a solid crystal of oxygen ions.
“That’s really strange behavior for water,” says study coauthor Marius Millot, a physicist at Lawrence Livermore National Laboratory in California. Although the superionic state was first predicted 30 years ago, “up until now we didn’t really know whether this was something that was real.”
At extremely high pressures, familiar substances like water can behave in unusual ways (SN: 1/14/12, p. 26). Working with a sample of ice that was crushed between two diamonds, Millot and colleagues used a laser to create a shock wave that plowed through the ice, boosting the pressure even more. At first, the density and temperature of the ice ramped up smoothly as the pressure increased. But at around 1.9 million times atmospheric pressure and 4,800 kelvins (about 4,500° Celsius), the scientists observed a jump in density and temperature. That jump, the researchers say, is evidence that superionic ice melted at that point. Although we normally think of ice as being cold, at high pressures, superionic ice can form even when heated. The melting occurred at just the conditions that theoretical calculations predict such ice would melt. The physicists didn’t measure the pressure at which the superionic phase first formed.
The electrical conductivity of the material provided another hint of superionic ice: The level of conductivity was consistent with expectations for that phase of matter. Whereas metals conduct electricity via the motion of electrons, in superionic ice, the flowing hydrogen ions transmit electricity. The researchers “provide quite good evidence” of the new phase, says Alexander Goncharov, a physicist at the Carnegie Institution for Science in Washington, D.C., who was not involved with the study.
Others are more cautious about the significance of the work. “It’s definitely providing more insight into water at these conditions,” says physicist Marcus Knudson of Washington State University in Pullman. But, he says, “I don’t see strong evidence that there’s a melting transition in their data.”
So more work remains before this weird kind of ice is fully understood. For now, the superionic state of water seems likelier, but still on thin ice.
The moon might have formed from the filling during Earth’s jelly doughnut phase.
Around 4.5 billion years ago, something hit Earth, and the moon appeared shortly after. A new simulation of how the moon formed suggests it took shape in the midst of a hot cloud of rotating rock and vapor, which (in theory) forms when big planetary objects smash into each other at high speeds and energies. Planetary scientists Simon Lock of Harvard University and Sarah Stewart of the University of California, Davis proposed this doughnut-shaped planetary blob in 2017 and dubbed it a synestia (SN: 8/5/17, p. 5). Radiation at the surface of this swirling cloud of vaporized, mixed-together planet matter sent rocky rain inward toward bigger debris. The gooey seed of the moon grew from fragments in this hot, high-pressure environment, with a bit of iron solidifying into the lunar core. Some elements, such as potassium and sodium, remained aloft in vapor, accounting for their scarcity in moon rocks today.
After a few hundred years, the synestia shrank and cooled. Eventually, a nearly full-grown moon emerged from the cloud and condensed. While Earth ended up with most of the synestia material, the moon spent enough time in the doughnut filling to gain similar ingredients, Lock, Stewart and colleagues write February 28 in Journal of Geophysical Research: Planets . The simulation shakes up the prevailing explanation for the moon’s birth: A Mars-sized protoplanet called Theia collided with Earth, and the moon formed from distinct rubble pieces. If that’s true, moon rocks should have very different chemical compositions than Earth’s. But they don’t.
Other recent studies have wrestled with why rocks from the moon and Earth are so alike (SN: 4/15/17, p. 18). Having a synestia in the mix shifts the focus from the nature of the collision to what happened in its aftermath, potentially resolving the conundrum.
On the hormonal roller coaster of life, the ups and downs of childbirth are the Tower of Power. For nine long months, a woman’s body and brain absorb a slow upwelling of hormones, notably progesterone and estrogen. The ovaries and placenta produce these two chemicals in a gradual but relentless rise to support the developing fetus.
With the birth of a baby, and the immediate expulsion of the placenta, hormone levels plummet. No other physiological change comes close to this kind of free fall in both speed and intensity. For most women, the brain and body make a smooth landing, but more than 1 in 10 women in the United States may have trouble coping with the sudden crash. Those new mothers are left feeling depressed, isolated or anxious at a time society expects them to be deliriously happy. This has always been so. Mental struggles following childbirth have been recognized for as long as doctors have documented the experience of pregnancy. Hippocrates described a woman’s restlessness and insomnia after giving birth. In the 19th century, some doctors declared that mothers were suffering from “insanity of pregnancy” or “insanity of lactation.” Women were sent to mental hospitals.
Modern medicine recognizes psychiatric suffering in new mothers as an illness like any other, but the condition, known as postpartum depression, still bears stigma. Both depression and anxiety are thought to be woefully underdiagnosed in new mothers, given that many women are afraid to admit that a new baby is anything less than a bundle of joy. It’s not the feeling they expected when they were expecting.
Treatment — when offered — most commonly involves some combination of antidepression medication, hormone therapy, counseling and exercise. Still, a significant number of mothers find these options wanting. Untreated, postpartum depression can last for years, interfering with a mother’s ability to connect with and care for her baby.
Although postpartum depression entered official medical literature in the 1950s, decades have passed with few new options and little research. Even as brain imaging has become a common tool for looking at the innermost workings of the mind, its use to study postpartum depression has been sparse. A 2017 review in Trends in Neurosciences found only 17 human brain imaging studies of postpartum depression completed through 2016. For comparison, more than four times as many have been conducted on a problem called “internet gaming disorder” — an unofficial diagnosis acknowledged only five years ago. Now, however, more researchers are turning their attention to this long-neglected women’s health issue, peering into the brains of women to search for the root causes of the depression. At the same time, animal studies exploring the biochemistry of the postpartum brain are uncovering changes in neural circuitry and areas in need of repair.
And for the first time, researchers are testing an experimental drug designed specifically for postpartum depression. Early results have surprised even the scientists.
Women’s health experts hope that these recent developments signal a new era of research to help new moms who are hurting.
“I get this question all the time: Isn’t it just depression during the postpartum period? My answer is no,” says neuroscientist Benedetta Leuner of Ohio State University. “It’s occurring in the context of dramatic hormonal changes, and that has to be impacting the brain in a unique way. It occurs when you have an infant to care for. There’s no other time in a woman’s life when the stakes are quite as high.”
Brain drain Even though progesterone and estrogen changes create hormonal whiplash, pregnancy wouldn’t be possible without them. Progesterone, largely coming from the ovaries, helps orchestrate a woman’s monthly menstrual cycle. The hormone’s primary job is to help thicken the lining of the uterus so it will warmly welcome a fertilized egg. In months when conception doesn’t happen, progesterone levels fall and the uterine lining disintegrates. If a woman becomes pregnant, the fertilized egg implants in the uterine wall and progesterone production is eventually taken over by the placenta, which acts like an extra endocrine organ.
Like progesterone, estrogen is a normal part of the menstrual cycle that kicks into overdrive after conception. In addition to its usual duties in the female body, estrogen helps encourage the growth of the uterus and fetal development, particularly the formation of the hormone-producing endocrine system.
These surges in estrogen and progesterone, along with other physiological changes, are meant to support the fetus. But the hormones, or chemicals made from them, cross into the mother’s brain, which must constantly adapt. When it doesn’t, signs of trouble can appear even before childbirth, although they are often missed. Despite the name “postpartum,” about half of women who become ill are silently distressed in the later months of pregnancy.
Decades ago, controversy churned over whether postpartum depression was a consequence of fluctuating hormones alone or something else, says neuroscientist Joseph Lonstein of Michigan State University in East Lansing. He studies the neurochemistry of maternal caregiving and postpartum anxiety. Lonstein says many early studies measured hormone levels in women’s blood and tried to determine whether natural fluctuations were associated with the risk of postpartum depression. Those studies found “no clear correlations with [women’s] hormones and their susceptibility to symptoms,” he says. “While the hormone changes are certainly thought to be involved, not all women are equally susceptible. The question then became, what is it about their brains that makes particular women more susceptible?” Seeking answers, researchers have examined rodent brains and placed women into brain scanners to measure the women’s responses to pictures or videos of babies smiling, babbling or crying. Though hormones likely underlie the condition, many investigations have led to the amygdalae. These two, almond-shaped clumps of nerve cells deep in the brain are sometimes referred to as the emotional thermostat for their role in the processing of emotions, particularly fear.
The amygdalae are entangled with many structures that help make mothers feel like mothering, says neuroscientist Alison Fleming of the University of Toronto Mississauga. The amygdalae connect to the striatum, which is involved in experiencing reward, and to the hippocampus, a key player in memory and the body’s stress response. And more: They are wired to the hypothalamus, the interface between the brain and the endocrine system (when you are afraid, the endocrine system produces adrenaline and other chemicals that get your heart racing and palms sweating). The amygdalae are also connected to the prefrontal cortex and insula, involved in decision making, motivation and other functions intertwined with maternal instinct.
Fleming and colleagues have recently moved from studies in postpartum rodents to human mothers. In one investigation, reported in 2012 in Social Neuroscience, women were asked to look at pictures of smiling infants while in a functional MRI, which images brain activity. In mothers who were not depressed, the researchers found a higher amygdala response, more positive feelings and lower stress when women saw their own babies compared with unfamiliar infants.
But an unexpected pattern emerged in mothers with postpartum depression, as the researchers reported in 2016 in Social Neuroscience. While both depressed and not-depressed mothers showed elevated amygdala activity when viewing their own babies, the depressed mothers also showed heightened responses to happy, unknown babies, suggesting reactions to the women’s own children were blunted and not unique. This finding may mean that depressed women had less inclination to emotionally attach to their babies.
Mothers with postpartum depression also showed weaker connectivity between the amygdalae and the insula. Mothers with weaker connectivity in this area had greater symptoms of depression and anxiety. Women with stronger connectivity were more responsive to their newborns.
While there’s still no way to definitely know that the amygdalae are responding to postpartum chemical changes, “it’s very likely,” Lonstein says, pointing out that the amygdalae are influenced by the body’s reaction to hormones in other emotional settings.
Maternal rewards While important, the amygdalae are just part of the puzzle that seems to underlie postpartum depression. Among others is the nucleus accumbens, famous for its role in the brain’s reward system and in addiction, largely driven by the yin and yang of the neurotransmitters dopamine and serotonin. In studies, mothers who watched films of their infants (as opposed to watching unknown infants) experienced increased production of feel-good dopamine. The women also had a strengthening of the connection between the nucleus accumbens, the amygdalae and other structures, researchers from Harvard Medical School and their collaborators reported in February 2017 in Proceedings of the National Academy of Sciences.
That’s not entirely surprising given that rodent mothers find interacting with their newborn pups as neurologically rewarding as addictive drugs, says Ohio State’s Leuner. Rodent mothers that are separated from their offspring “will press a bar 100 times an hour to get to a pup. They will step across electrified grids to get to their pups. They’ve even been shown in some studies to choose the pups over cocaine.” Mothers find their offspring “highly, highly rewarding,” she says.
When there are postpartum glitches in the brain’s reward system, women may find their babies less satisfying, which could increase the risk for impaired mothering. Writing in 2014 in the European Journal of Neuroscience, Leuner and colleagues reported that in rats with symptoms of postpartum depression (induced by stress during pregnancy, a major risk factor for postpartum depression in women), nerve cells in the nucleus accumbens atrophied and showed fewer protrusions called dendritic spines — suggesting weaker connections to surrounding nerve cells compared with healthy rats. This is in contrast to other forms of depression, which show an increase in dendritic spines. Unpublished follow-up experiments conducted by Leuner’s team also point to a role for oxytocin, a hormone that spikes with the birth of a baby as estrogen and progesterone fall. Sometimes called the “cuddle chemical,” oxytocin is known for its role in maternal bonding (SN Online: 4/16/15). Leuner hypothesizes that maternal depression is associated with deficits in oxytocin receptors that enable the hormone to have its effects as part of the brain’s reward system.
If correct, the idea may help explain why oxytocin treatment failed women in some studies of postpartum depression. The hormone may simply not have the same potency in some women whose brains are short on receptors the chemical can latch on to. The next step is to test whether reversing the oxytocin receptor deficits in rodents’ brains relieves symptoms.
Leuner and other scientists emphasize that the oxytocin story is complex. In 2017, in a study reported in Depression & Anxiety, women without a history of depression who received oxytocin — which is often given to promote contractions or stem bleeding after delivery — had a 32 percent higher likelihood of developing postpartum depression than women who did not receive the hormone. In more than 46,000 births, 5 percent of women who did not receive the hormone were diagnosed with depression, compared with 7 percent who did.
“This was the opposite of what we predicted,” says Kristina Deligiannidis, a neuroscientist and perinatal psychiatrist at the Feinstein Institute for Medical Research in Manhasset, N.Y. After all, oxytocin is supposed to enhance brain circuits involved in mothering. “We had a whole group of statisticians reanalyze the data because we didn’t believe it,” she says. While the explanation is unknown, one theory is that perhaps the women who needed synthetic oxytocin during labor weren’t making enough on their own — and that could be why they are more prone to depression after childbirth.
But postpartum depression can’t be pinned to any single substance or brain malfunction — it doesn’t reside in one tidy nest of brain cells, or any one chemical process gone haywire. Maternal behavior is based on complex neurological circuitry. “Multiple parts of the brain are involved in any single function,” Deligiannidis says. “Just to have this conversation, I’m activating several different parts of my brain.” When any kind of depression occurs, she says, multiple regions of the brain are suffering from a communication breakdown.
Looking further, Deligiannidis has also examined the role of certain steroids synthesized from progesterone and other hormones and known to affect maternal brain circuitry. In a 2016 study in Psychoneuroendocrinology involving 32 new mothers at risk for postpartum depression and 24 healthy mothers, Deligiannidis and colleagues reported that concentrations of some steroids that affect the brain, also called neurosteroids, were higher in women at risk for developing depression (because of their past history or symptoms), compared with women who were not. The higher levels suggest a system out of balance — the brain is making too much of one neurosteroid and not enough of another, called allopregnanolone, which is thought to protect against postpartum depression and is being tested as a treatment. Treating pregnancy withdrawal Beyond mom
CASEZY IDEA/SHUTTERSTOCK Postpartum depression doesn’t weigh down just mom. Research suggests it might have negative effects on her offspring that can last for years. Risks include:
Newborns Higher levels of cortisol and other stress hormones More time fussing and crying More “indeterminate sleep,” hovering between deep and active sleep Infants and children Increased risk of developmental problems Slower growth Lower cognitive function Elevated cortisol levels Adolescents Higher risk of depression Tufts University neuroscientist Jamie Maguire, based in Boston, got interested in neurosteroids during her postgraduate studies in the lab of Istvan Mody at UCLA. Maguire and Mody reported in 2008 in Neuron that during pregnancy, the hippocampus has fewer receptors for neurosteroids, presumably to protect the brain from the massive levels of progesterone and estrogen circulating at that time. When progesterone drops after birth, the receptors repopulate.
But in mice genetically engineered to lack those receptors, something else happened: The animals were less interested in tending to their offspring, failing to make nests for them.
“We started investigating. Why are these animals having these abnormal postpartum behaviors?” Maguire recalls. Was an inability to recover these receptors making some women susceptible? Interestingly, similar receptors are responsible for the mood-altering and addictive effects of some antianxiety drugs, suggesting that the sudden progesterone drop after childbirth could be leaving some women with a kind of withdrawal effect.
Further experiments demonstrated that giving the mice a progesterone-derived neurosteroid — producing levels close to what the mice had in pregnancy — alleviated the symptoms.
Today, Maguire is on the scientific advisory board of Boston area–based Sage Therapeutics, which is testing a formulation of allopregnanolone called brexanolone. Results of an early clinical trial published last July in The Lancet assessed whether brexanolone would alleviate postpartum symptoms in women with severe postpartum depression. The study involved 21 women randomly assigned to receive a 60-hour infusion of the drug or a placebo within six months after delivery.
At the end of treatment, the women who received the drug reported a 21-point reduction on a standard scale of depression symptoms, compared with about 9 points for the women on a placebo. “These women got better in about a day,” says Deligiannidis, who is on the study’s research team. “The results were astonishing.”
In November, Sage Therapeutics announced the results of two larger studies, although neither has been published. Combined, the trials involved 226 women with severe or moderate postpartum depression. Both groups showed similar improvements that lasted for the month the women were followed. The company has announced plans to request approval from the U.S. Food and Drug Administration to market brexanolone in the United States. This is an important first step, researchers say, toward better treatments.
“We are just touching on one small piece of a bigger puzzle,” says Jodi Pawluski, a neuroscientist at the Université de Rennes 1 in France who coauthored the 2017 review in Trends in Neurosciences. She was surprised at the dearth of research, given how common postpartum depression is. “This is not the end, it’s the beginning.”
Tyrannosaurus rex isn’t just a king to paleontologists — the dinosaur increasingly reigns over the world of art auctions. A nearly complete skeleton known as Stan the T. rex smashed records in October 2020 when a bidding war drove its price to $31.8 million, the highest ever paid for any fossil. Before that, Sue the T. rex held the top spot; it went for $8.3 million in 1997.
That kind of publicity — and cachet — means that T. rex’s value is sky-high, and the dinosaur continues to have its teeth firmly sunk into the auction world in 2022. In December, Maximus, a T. rex skull, will be the centerpiece of a Sotheby’s auction in New York City. It’s expected to sell for about $15 million.
Another T. rex fossil named Shen was anticipated to sell for between $15 million and $25 million at a Christie’s auction in Hong Kong in late November. However, the auction house pulled it over concerns about the number of replica bones used in the fossil. “These are astronomical sums of money, really surprising sums of money,” says Donna Yates, a criminologist at Maastricht University in the Netherlands who studies high-value collectibles.
Stan’s final price “was completely unexpected,” Yates says. The fossil was originally appraised at about $6 million — still a very large sum, though nothing like the final tally, which was the result of a three-way bidding war.
But the staggering amounts of money T. rex fossils now fetch at auction can mean a big loss for science. At those prices, the public institutions that might try to claim these glimpses into the deep past are unable to compete with deep-pocketed private buyers, researchers say.
One reason for the sky-high prices may be that T. rex fossils are increasingly being treated more like rare works of art than bits of scientific evidence, Yates says. The bones might once have been bought and sold at dusty “cowboy fossil” dealerships. But nowadays these fossils are on display in shiny gallery spaces and are being appraised and marketed as rare objets d’art. That’s appealing to collectors, she adds: “If you’re a high-value buyer, you’re a person who wants the finest things.”
But fossils’ true value is the information they hold, says Thomas Carr, a paleontologist at Carthage College in Kenosha, Wis. “They are our only means of understanding the biology and evolution of extinct animals.”
Keeping fossils of T. rex and other dinosaurs and animals in public repositories, such as museums, ensures that scientists have consistent access to study the objects, including being able to replicate or reevaluate previous findings. But a fossil sold into private or commercial hands is subject to the whim of its owner — which means anything could happen to it at any time, Carr says. “It doesn’t matter if [a T. rex fossil] is bought by some oligarch in Russia who says scientists can come and study it,” he says. “You might as well take a sledgehammer to it and destroy it.”
A desire for one’s own T. rex There are only about 120 known specimens of T. rex in the world. At least half of them are owned privately and aren’t available to the public. That loss is “wreaking havoc on our dataset. If we don’t have a good sample size, we can’t claim to know anything about [T. rex],” Carr says.
For example, to be able to tell all the ways that T. rex males differed from females, researchers need between 70 and 100 good specimens for statistically significant analyses, an amount scientists don’t currently have.
Similarly, scientists know little about how T. rex grew, and studying fossils of youngsters could help (SN: 1/6/20). But only a handful of juvenile T. rex specimens are publicly available to researchers. That number would double if private specimens were included.
Museums and academic institutions typically don’t have the kind of money it takes to compete with private bidders in auctions or any such competitive sales. That’s why, in the month before Stan went up for auction in 2020, the Society for Vertebrate Paleontology, or SVP, wrote a letter to Christie’s asking the auction house to consider restricting bidding to public institutions. The hope was that this would give scientists a fighting chance to obtain the specimens.
But the request was ignored — and unfortunately may have only increased publicity for the sale, says Stuart Sumida, a paleontologist at California State University in San Bernardino and SVP’s current vice president. That’s why SVP didn’t issue a public statement this time ahead of the auctions for Shen and Maximus, Sumida says, though the organization continues to strongly condemn fossil sales — whether of large, dramatic specimens or less well-known creatures. “All fossils are data. Our position is that selling fossils is not scientific and it damages science.”
Sumida is particularly appalled at statements made by auction houses that suggest the skeletons “have already been studied,” an attempt to reassure researchers that the data contained in that fossil won’t be lost, regardless of who purchases it. That’s deeply misleading, he says, because of the need for reproducibility, as well as the always-improving development of new analysis techniques. “When they make public statements like that, they are undermining not only paleontology, but the scientific process as well.”
And the high prices earned by Stan and Sue are helping to drive the market skyward, not only for other T. rex fossils but also for less famous species. “It creates this ripple effect that is incredibly damaging to science in general,” Sumida says. Sotheby’s, for example, auctioned off a Gorgosaurus, a T. rex relative, in July for $6.1 million. In May, a Deinonychus antirrhopus — the inspiration for Jurassic Park’s velociraptor — was sold by Christie’s for $12.4 million.
Protecting T. rex from collectors Compounding the problem is the fact that the United States has no protections in place for fossils unearthed from the backyards or dusty fields of private landowners. The U.S. is home to just about every T. rex skeleton ever found. Stan, Sue and Maximus hail from the Black Hills of South Dakota. Shen was found in Montana.
As of 2009, U.S. law prohibits collecting scientifically valuable fossils, particularly fossils of vertebrate species like T. rex, from public lands without permits. But fossils found on private lands are still considered the landowner’s personal property. And landowners can grant digging access to whomever they wish. Before the discovery of Sue the T. rex (SN: 9/6/14), private owners often gave scientific institutions free access to hunt for fossils on their land, says Bridget Roddy, currently a researcher at the legal news company Bloomberg Law in Washington, D.C. But in the wake of Sue’s sale in 1997, researchers began to have to compete for digging access with commercial fossil hunters.
These hunters can afford to pay landowners large sums for the right to dig, or even a share of the profits from fossil sales. And many of these commercial dealers sell their finds at auction houses, where the fossils can earn far more than most museums are able to pay.
Lack of federal protections for paleontological resources found on private land — combined with the large available supply of fossils — is a situation unique to the United States, Roddy says. Fossil-rich countries such as China, Canada, Italy and France consider any such finds to be under government protection, part of a national legacy.
In the United States, seizing such materials from private landowners — under an eminent domain argument — would require the government to pay “just compensation” to the landowners. But using eminent domain to generally protect such fossils wouldn’t be financially sustainable for the government, Roddy says, not least because most fossils dug up aren’t of great scientific value anyway.
There may be other, more grassroots ways to at least better regulate fossil sales, she says. While still a law student at DePaul University in Chicago, Roddy outlined some of those ideas in an article published in Texas A&M Journal of Property Law in May.
One option, she suggests, is for states to create a selective sales tax attached to fossil purchases, specifically for buyers who intend to keep their purchases in private collections that are not readily available to the public. It’s “similar to if you want to buy a pack of cigarettes, which is meant to offset the harm that buying cigarettes does to society in general,” Roddy says. That strategy could be particularly effective in states with large auction houses, like New York.
Another possibility is to model any new, expanded fossil preservation laws on existing U.S. antiquities laws, intended to preserve cultural heritage. After all, Roddy says, fossils aren’t just bones, but they’re also part of the human story. “Fossils have influenced our folklore; they’re a unifier of humanity and culture rather than a separate thing.”
Though fossils from private lands aren’t protected, many states do impose restrictions on searches for archaeological and cultural artifacts, by requiring those looking for antiquities to restore excavated land or by fining the excavation of certain antiquities without state permission. Expanding those restrictions to fossil hunting, perhaps by requiring state approval through permits, could also give states the opportunity to purchase any significant finds before they’re lost to private buyers.
Preserving fossils for science and the public Such protections could be a huge boon to paleontologists, who may not even know what’s being lost. “The problem is, we’ll never know” all the fossils that are being sold, Sumida says. “They’re shutting scientists out of the conversation.”
And when it comes to dinosaurs, “so many of the species we know about are represented by a single fossil,” says Stephen Brusatte, a paleontologist at the University of Edinburgh. “If that fossil was never found, or disappeared into the vault of a collector, then we wouldn’t know about that dinosaur.”
Or, he says, sometimes a particularly complete or beautifully preserved dinosaur skeleton is found, and without it, “we wouldn’t be able to study what that dinosaur looked like, how it moved, what it ate, how it sensed its world, how it grew.”
The point isn’t to put restrictions on collecting fossils so much as making sure they remain in public view, Brusatte adds. “There’s nothing as magical as finding your own fossils, being the first person ever to see something that lived millions of years ago.” But, he says, unique and scientifically invaluable fossils such as dinosaur skeletons should be placed in museums “where they can be conserved and studied and inspire the public, rather than in the basements or yachts of the oligarch class.”
After its record-breaking sale, Stan vanished for a year and a half, its new owners a mystery. Then in March 2022, news surfaced that the fossil had been bought by the United Arab Emirates, which stated it intends to place Stan in a new natural history museum.
Sue, too, is on public view. The fossil is housed at Chicago’s Field Museum of Natural History, thanks to the pooled financial resources of the Walt Disney Corporation, the McDonald Corporation, the California State University System and others. That’s the kind of money it took to get the highest bid on a T. rex 25 years ago.
And those prices only seem to be going up. Researchers got lucky with Sue, and possibly Stan.
As for Shen, the fossil’s fate remains in limbo: It was pulled from auction not due to outcry from paleontologists, but over concerns about intellectual property rights. The fossil, at 54 percent complete, may have been supplemented with a polyurethane cast of bones from Stan, according to representatives of the Black Hills Institute of Geological Research in Hill City, S.D. That organization, which discovered Stan, retains a copyright over the skeleton.
In response to those concerns, Christie’s pulled the lot, and now says that it intends to loan the fossil to a museum. But this move doesn’t reassure paleontologists. “A lot of people are pleased that the sale didn’t go through,” Sumida says. “But it sort of just kicks the can down the road.… It doesn’t mean they’re not going to try and sell it in another form, somewhere down the road.”
Ultimately, scientists simply can’t count on every important fossil finding its way to the public, Carr says. “Those fossils belong in a museum; it’s right out of Indiana Jones,” he says. “It’s not like they’re made in a factory somewhere. Fossils are nonrenewable resources. Once Shen is gone, it’s gone.”
The infant universe transforms from a featureless landscape to an intricate web in a new supercomputer simulation of the cosmos’s formative years.
An animation from the simulation shows our universe changing from a smooth, cold gas cloud to the lumpy scattering of galaxies and stars that we see today. It’s the most complete, detailed and accurate reproduction of the universe’s evolution yet produced, researchers report in the November Monthly Notices of the Royal Astronomical Society.
This virtual glimpse into the cosmos’s past is the result of CoDaIII, the third iteration of the Cosmic Dawn Project, which traces the history of the universe, beginning with the “cosmic dark ages” about 10 million years after the Big Bang. At that point, hot gas produced at the very beginning of time, about 13.8 billion years ago, had cooled to a featureless cloud devoid of light, says astronomer Paul Shapiro of the University of Texas at Austin. Roughly 100 million years later, tiny ripples in the gas left over from the Big Bang caused the gases to clump together (SN: 2/19/15). This led to long, threadlike strands that formed a web of matter where galaxies and stars were born.
As radiation from the early galaxies illuminated the universe, it ripped electrons from atoms in the once-cold gas clouds during a period called the epoch of reionization, which continued until about 700 million years after the Big Bang (SN: 2/6/17).
CoDaIII is the first simulation to fully account for the complicated interaction between radiation and the flow of matter in the universe, Shapiro says. It spans the time from the cosmic dark ages and through the next several billion years as the distribution of matter in the modern universe formed.
The animation from the simulation, Shapiro says, graphically shows how the structure of the early universe is “imprinted on the galaxies today, which remember their youth, or their birth or their ancestors from the epoch of reionization.”
Growing up in Brazil, Marcos Simões-Costa often visited his grandparents’ farm in the Amazon. That immersion in nature — squawking toucans and all — sparked his fascination with science and evolution. But a video of a developing embryo, shown in his middle school science class, cemented his desire to become a developmental biologist.
“It’s such a beautiful process,” he says. “I was always into drawing and art, and it was very visual — the shapes of the embryo changing, the fact that you start with one cell and the complexity is increasing. I just got lost in that video.”
Today, Simões-Costa, of Harvard Medical School and Boston Children’s Hospital, is honoring his younger self by demystifying how the embryo develops. He studies the embryos and stem cells of birds and mice to learn how networks of genes and the elements that control them influence the identity of cells. The work could lead to new treatments for various diseases, including cancer.
“The embryo is our best teacher,” he says. Standout research Simões-Costa focuses on the embryo’s neural crest cells, a population of stem cells that form in the developing central nervous system. The cells migrate to other parts of the embryo and give rise to many different cell types, from the bone cells of the face to muscle cells to brain and nerve cells.
Scientists have wondered for years why, despite being so similar, neural crest cells in the cranial region of the embryo can form bone and cartilage, while those in the trunk region can’t form either. While a postdoc at Caltech, Simões-Costa studied the cascade of molecules that govern how genes are expressed in each cell type. With his adviser, developmental biologist Marianne Bronner, he identified transcription factors — proteins that can turn genes on and off — that were present only in cranial cells. Transplanting the genes for those proteins into trunk cells endowed the cells with the ability to create cartilage and bone.
Now in his own lab, he continues to piece together just how this vast regulatory network influences the specialization of cells. His team reconstructed how neural crest cells’ full set of genetic instructions, or the genome, folds into a compact, 3-D shape. The researchers identified short DNA sequences, called enhancers, that are located in faraway regions of the genome, but end up close to key genes when the genome folds. These enhancers work with transcription factors and other regulatory elements to control gene activity.
Simões-Costa is also using neural crest cells to elucidate a strange behavior shared by cancer cells and some embryonic cells. These cells produce energy anaerobically, without oxygen, even when oxygen is present. Called the Warburg effect, this metabolic process has been studied extensively in cancer cells, but its function remained unclear.
Colored tracks representing cell movements.. Through experiments manipulating the metabolism of neural crest cells, Simões-Costa’s team found that the Warburg effect is necessary for the cells to move around during early development. The mechanism, which should stay turned off in nonembryonic cells, somehow “gets reactivated in adult cells in the context of cancer, leading those cells to become more migratory and more invasive,” Simões-Costa says.
“He’s one of the few people who’s really looked at [this process in neural crest cells] at a molecular level and done a deep dive into the mechanisms underlying it,” says Bronner.
Cleverly combining classical embryological methods with the latest genomic technologies to address fundamental questions in developmental biology is what makes Simões-Costa special, says Kelly Liu, a developmental biologist at Cornell University. He wants to understand not only what individual genes do, but how they work at a systems level, she says.
What’s next How does the genetic blueprint tell cells where they are in the embryo, and what they should be doing? How do cancer cells hijack the Warburg effect, and could understanding of that process lead to new treatments? These are some of the questions Simões-Costa wants to tackle next.
“It’s been 20 years since the Human Genome Project came to a conclusion,” he says, referring to the massive effort to read the human genetic instruction book. “But there’s still so much mystery in the genetic code.”
Those mysteries, plus a deep passion for lab work, fuel Simões-Costa’s research. “Being at the bench is when I’m the happiest,” he says. He likens the delicate craft of performing precise surgeries on tissues and cells to meditation. “It does not get old.”
The glossy leaves and branching roots of mangroves are downright eye-catching, and now a study finds that the moon plays a special role in the vigor of these trees.
Long-term tidal cycles set in motion by the moon drive, in large part, the expansion and contraction of mangrove forests in Australia, researchers report in the Sept. 16 Science Advances. This discovery is key to predicting when stands of mangroves, which are good at sequestering carbon and could help fight climate change, are most likely to proliferate (SN: 11/18/21). Such knowledge could inform efforts to protect and restore the forests. Mangroves are coastal trees that provide habitat for fish and buffer against erosion (SN: 9/14/22). But in some places, the forests face a range of threats, including coastal development, pollution and land clearing for agriculture. To get a bird’s-eye view of these forests, Neil Saintilan, an environmental scientist at Macquarie University in Sydney, and his colleagues turned to satellite imagery. Using NASA and U.S. Geological Survey Landsat data from 1987 to 2020, the researchers calculated how the size and density of mangrove forests across Australia changed over time.
After accounting for persistent increases in these trees’ growth — probably due to rising carbon dioxide levels, higher sea levels and increasing air temperatures — Saintilan and his colleagues noticed a curious pattern. Mangrove forests tended to expand and contract in both extent and canopy cover in a predictable manner. “I saw this 18-year oscillation,” Saintilan says.
That regularity got the researchers thinking about the moon. Earth’s nearest celestial neighbor has long been known to help drive the tides, which deliver water and necessary nutrients to mangroves. A rhythm called the lunar nodal cycle could explain the mangroves’ growth pattern, the team hypothesized.
Over the course of 18.6 years, the plane of the moon’s orbit around Earth slowly tips. When the moon’s orbit is the least tilted relative to our planet’s equator, semidiurnal tides — which consist of two high and two low tides each day — tend to have a larger range. That means that in areas that experience semidiurnal tides, higher high tides and lower low tides are generally more likely. The effect is caused by the angle at which the moon tugs gravitationally on the Earth.
Saintilan and his colleagues found that mangrove forests experiencing semidiurnal tides tended to be larger and denser precisely when higher high tides were expected based on the moon’s orbit. The effect even seemed to outweigh other climatic drivers of mangrove growth, such as El Niño conditions. Other regions with mangroves, such as Vietnam and Indonesia, probably experience the same long-term trends, the team suggests.
Having access to data stretching back decades was key to this discovery, Saintilan says. “We’ve never really picked up before some of these longer-term drivers of vegetation dynamics.”
It’s important to recognize this effect on mangrove populations, says Octavio Aburto-Oropeza, a marine ecologist at the Scripps Institution of Oceanography in La Jolla, Calif., who was not involved in the research.
Scientists now know when some mangroves are particularly likely to flourish and should make an extra effort at those times to promote the growth of these carbon-sequestering trees, Aburto-Oropeza says. That might look like added limitations on human activity nearby that could harm the forests, he says. “We should be more proactive.”
Cocooned within the bowels of the Earth, one mineral’s metamorphosis into another may trigger some of the deepest earthquakes ever detected.
These cryptic tremors — known as deep-focus earthquakes — are a seismic conundrum. They violently rupture at depths greater than 300 kilometers, where intense temperatures and pressures are thought to force rocks to flow smoothly. Now, experiments suggest that those same hellish conditions might also sometimes transform olivine — the primary mineral in Earth’s mantle — into the mineral wadsleyite. This mineral switch-up can destabilize the surrounding rock, enabling earthquakes at otherwise impossible depths, mineral physicist Tomohiro Ohuchi and colleagues report September 15 in Nature Communications. “It’s been a real puzzle for many scientists because earthquakes shouldn’t occur deeper than 300 kilometers,” says Ohuchi, of Ehime University in Matsuyama, Japan.
Deep-focus earthquakes usually occur at subduction zones where tectonic plates made of oceanic crust — rich in olivine — plunge toward the mantle (SN: 1/13/21). Since the quakes’ seismic waves lose strength during their long ascent to the surface, they aren’t typically dangerous. But that doesn’t mean the quakes aren’t sometimes powerful. In 2013, a magnitude 8.3 deep-focus quake struck around 609 kilometers below the Sea of Okhotsk, just off Russia’s eastern coast.
Past studies hinted that unstable olivine crystals could spawn deep quakes. But those studies tested other minerals that were similar in composition to olivine but deform at lower pressures, Ohuchi says, or the experiments didn’t strain samples enough to form faults.
He and his team decided to put olivine itself to the test. To replicate conditions deep underground, the researchers heated and squeezed olivine crystals up to nearly 1100° Celsius and 17 gigapascals. Then the team used a mechanical press to further compress the olivine slowly and monitored the deformation.
From 11 to 17 gigapascals and about 800° to 900° C, the olivine recrystallized into thin layers containing new wadsleyite and smaller olivine grains. The researchers also found tiny faults and recorded bursts of sound waves — indicative of miniature earthquakes. Along subducting tectonic plates, many of these thin layers grow and link to form weak regions in the rock, upon which faults and earthquakes can initiate, the researchers suggest.
“The transformation really wreaks havoc with the [rock’s] mechanical stability,” says geophysicist Pamela Burnley of the University of Nevada, Las Vegas, who was not involved in the research. The findings help confirm that olivine transformations are enabling deep-focus earthquakes, she says.
Next, Ohuchi’s team plans to experiment on olivine at even higher pressures to gain insights into the mineral’s deformation at greater depths.
