New research suggests our earliest mammalian ancestors used powerful night-time vision to find food and avoid reptilian predators that hunted by day.
The study, published in Scientific Reports, used genetic data to support existing fossil evidence suggesting that our distant relatives may have adapted to life in the dark.
Researchers examined genes involved in night vision in animals throughout the evolutionary tree, looking for places where those genes became enhanced.
“This method is like using the genome as a fossil record, and with it we’ve shown when genes involved in night vision appear,” says Liz Hadly, professor of biology at Stanford University and senior author of the paper. “It’s a very powerful way of corroborating a story that has been, up to now, only hypothesized.”
Mammals and reptiles share a common ancestor, with the earliest mammal-like animals appearing in the Late Triassic (about 200 million years ago). Fossil evidence suggests that early mammals had excellent hearing and sense of smell and were likely also warm-blooded. All of these features are common in their descendants, the living mammals, most of whom are nocturnal. Therefore, experts have hypothesized that early mammals were also nocturnal. This study offers direct, genetic evidence for that hypothesis.
To trace the evolution of nocturnality, the researchers studied genes that lead author and visiting scholar Yonghua Wu had previously found associated with night vision in certain birds, such as owls.
The team members examined those night-vision genes in many mammals and reptiles, including snakes, alligators, mice, platypuses, and humans. Using what they know about how those animals are related, they figured out when in their evolutionary histories, if ever, the function of these genes was enhanced.
From this, they deduced that the earliest common ancestor did not have good night vision and was instead active during the day. However, soon after the split, mammals began enhancing their night vision genes, allowing them to begin to roam at night, thus avoiding the reptiles that hunted during the day.
“Early mammals coexisted with early reptiles in the Age of the Dinosaurs and somehow escaped extinction,” Wu says. “This research further supports the hypothesis that diurnal reptiles, such as lizards, snakes, and their relatives, competed with mammals and may have led them to better adapt to dim light conditions.”
In the millions of years that have elapsed since mammals and reptiles diverged, natural selection and evolution haven’t stopped. Not all mammals are still nocturnal. Some groups of mammals have reoccupied the day, adapting in various ways to daylight activity. These animals include cheetahs, pikas, camels, elephants, and, of course, humans.
“Understanding the constant pressure to get better at seeing the world at night for over 100 million years is a beautiful way of thinking about evolution,” Hadly says. “We think of it as something simple—seeing in the light or the dark—but these genes are being constantly refined and altered by natural selection.”This frog took a bizarre path to see blue
The methods in this study could apply to different areas of the animal evolutionary tree to learn more about the evolution of vision, including how humans made the switch to bright-light vision. This study is also an example of how little information we have about the first mammals, compared to what we know about our ancient and more compelling reptile cousins, the dinosaurs.
“When people talk about the dinosaur age, even when you look at cartoons, the focus is mainly on dinosaurs,” says Haifeng Wang, coauthor of the paper and postdoctoral research fellow with Stanley Qi, an assistant professor of bioengineering. “This ancient period is an important piece of the story of our evolution too. We want to know better what the mammals were like then.”
Hadly is also a senior fellow at the Stanford Woods Institute for the Environment, faculty director of Jasper Ridge Biological Preserve, and a member of Stanford Bio-X.
Funding came from the National Natural Science Foundation of China, the grant of China Scholarship Council, the Fundamental Research Funds for the Central Universities, and Stanford University.
Source: Stanford University
Sunflower seeds and products made from them are often contaminated with a toxin produced by molds, report researchers. This poses an increased health risk in many low-income countries worldwide.
In a new study, a team of scientists documented frequent occurrence of aflatoxin—a toxin produced by Aspergillus molds that commonly infect corn, peanuts, pistachios, and almonds—in sunflower seeds and their products. The study, published in PLOS ONE, is one of the first to associate aflatoxin contamination with sunflower seeds.
The study took place in Tanzania, but the problem is by no means isolated there. Chronic exposure to aflatoxin causes an estimated 25,000-155,000 deaths worldwide each year from corn and peanuts alone.
Since it is one of the most potent liver carcinogens known, the research to detect and limit its presence in sunflower seeds and their products could help save lives and reduce liver disease in areas where people eat sunflowers and their byproducts, says coauthor Gale Strasburg, a food science and human nutrition professor at Michigan State University.
“These high aflatoxin levels, in a commodity frequently consumed by the Tanzanian population, indicate that local authorities must implement interventions to prevent and control aflatoxin contamination along the sunflower commodity value chain, to enhance food and feed safety in Tanzania,” says Strasburg.
“Billions of people worldwide are exposed to aflatoxin in their diets, particularly in places where food is not monitored regularly for contaminants…”
“Follow-up research is needed to determine intake rates of sunflower seed products in humans and animals, to inform exposure assessments and to better understand the role of sunflower seeds and cakes as a dietary aflatoxin source,” he adds.
Smallholder farmers in Tanzania grow sunflowers for the seeds, which they sell to local millers who press the seeds for oil to sell to local consumers for cooking. People use the remaining cakes as animal feed.
The seeds become infected by Aspergillus flavus or Aspergillus parasiticus, molds that produce aflatoxin. This contamination has been well studied in other crops, but there is little research published on sunflower seed contamination.Mold on corn can cause liver cancer
Juma Mmongoyo, a former food science doctoral student and lead author of the study, analyzed aflatoxin levels of seeds and cakes in seven regions of Tanzania in 2014 and 2015. Nearly 60 percent of seed samples and 80 percent of cake samples were contaminated with aflatoxins.
In addition, 14 percent of seeds and 17 percent of cakes were contaminated above 20 parts per billion, the level considered safe by the US Food and Drug Administration. Some samples had levels of several hundred parts per billion.
“Billions of people worldwide are exposed to aflatoxin in their diets, particularly in places where food is not monitored regularly for contaminants,” says Felicia Wu, study coauthor.
“Our previous work with the World Health Organization on the global burden of foodborne disease showed that aflatoxin is one of the chemical contaminants that causes the greatest disease burden worldwide,” she adds.Transgenic corn keeps toxic fungus under control
To help solve that problem, Wu founded the Center for the Health Impacts of Agriculture. The center tackles global issues, such as antibiotics given to livestock and poultry that seep into soil and nearby bodies of water, and the association between malaria incidence and irrigation patterns in sub-Saharan Africa.
Additional researchers from Michigan State and the Sokoine University of Agriculture in Tanzania also contributed to this research.
Source: Michigan State University
Lingering, wandering pesticides can put honey bees—which pollinate crops in the growing season—in danger, according to a new study of their own food.
Researchers placed 120 pristine honey bee colonies near 30 apple orchards around New York state. After allowing the bees to forage for several days during the apple flowering period, they examined each hive’s “beebread”—the bees’ food stores made from gathered pollen—to search for traces of pesticides.
In 17 percent of colonies, the beebread showed acutely high levels of pesticide exposure, while 73 percent revealed chronic exposure.
“Our data suggest pesticides are migrating through space and time,” says Scott McArt, assistant professor of entomology at Cornell University and lead author of the study in Nature Scientific Reports. Bees may be gathering pollen from non-target wildflowers, field margins, and weeds like dandelions where insecticides seem to linger.Could scientists breed more resilient honey bees?
“Surprisingly, there is not much known about the magnitude of risk or mechanisms of pesticide exposure when honey bees are brought in to pollinate major agricultural crops,” he says. “Beekeepers are very concerned about pesticides, but there’s very little field data. We’re trying to fill that gap in knowledge, so there’s less mystery and more fact regarding this controversial topic.”
More than 60 percent of the pesticides that were found can be attributed to orchards and surrounding farmland that were not sprayed during the apple bloom season. Persistent insecticides aimed at other crops may be surrounding the orchards, McArt says. In addition, pre-bloom sprays in orchards may accumulate in nearby flowering weeds.
“We found risk was attributed to many different types of pesticides. Neonicotinoids were not the whole story, but they were part of the story,” he says. “Because neonicotinoids are persistent in the environment and accumulate in pollen and nectar, they are of concern. But one of our major findings is that many other pesticides contribute to risk.”
Mass-blooming crops flower in big bursts during the pollination season, so crop producers rent armies of honey bees to supplement the work of wild bees. “There are so many flowers at one given time, often there may not be enough wild bees to perform sufficient pollination services,” McArt says.Watch: Honey bees clean pollen off their hairy eyes
Crop pollination by insects, particularly bees, can be valued at more than $15 billion annually to the US economy, according to research by Nicholas Calderone, professor emeritus of entomology. Producers and beekeepers are now concerned about the high rates of hive declines—estimated to be about 42 percent in 2014-15 domestically.
To understand the economics, beekeepers may charge more than $100 per colony for pollination services for apple producers in New York, almond producers in California, and blueberry growers in North Carolina. For large farms, several hundred to a thousand pollinating colonies are brought in via large trucks.
Commercial beekeepers sometimes assume they will lose entire colonies, which is why pollination service rates have tripled or quadrupled over the past 15 years, McArt says. He recently shared his research with growers at a New York State Integrated Pest Management meeting, and several farmers said they are interested in altering crop management practices to reduce honey bee injury.
The New York State Department of Environmental Conservation and the Department of Agriculture and Markets assembled a Pollinator Protection Plan in 2016. Scientists are developing best management practices, reviving pollinator populations, researching and monitoring, and developing outreach and educational programs for beekeepers and producers.
The New York Farm Viability Institute funded this research.
Source: Cornell University
New research suggests that excess sugar—especially the fructose in sugary drinks—might damage your brain.
Researchers using data from the Framingham Heart Study (FHS) found that people who drink sugary beverages frequently are more likely to have poorer memory, smaller overall brain volume, and a significantly smaller hippocampus—an area of the brain important for learning and memory.
But before you chuck your sweet tea and reach for a diet soda, there’s more: a follow-up study found that people who drank diet soda daily were almost three times as likely to develop stroke and dementia when compared to those who did not.
Researchers are quick to point out that these findings, which appear separately in the journals Alzheimer’s & Dementia and Stroke, demonstrate correlation but not cause-and-effect. While researchers caution against over-consuming either diet soda or sugary drinks, more research is needed to determine how—or if—these drinks actually damage the brain, and how much damage may be caused by underlying vascular disease or diabetes.
“Maybe good old-fashioned water is something we need to get used to…”
“These studies are not the be-all and end-all, but it’s strong data and a very strong suggestion,” says Sudha Seshadri, a professor of neurology at Boston University School of Medicine and a faculty member at the university’s Alzheimer’s Disease Center. “It looks like there is not very much of an upside to having sugary drinks, and substituting the sugar with artificial sweeteners doesn’t seem to help.”
“Maybe good old-fashioned water is something we need to get used to,” adds Seshadri, who is senior author of both papers.
Excess sugar has long been associated with cardiovascular and metabolic diseases like obesity, heart disease, and type 2 diabetes, but little is known about its long-term effects on the human brain, says Matthew Pase, a fellow in the university’s neurology department, an investigator at the FHS, and lead author of both papers.
He chose to study sugary drinks as a way of examining overall sugar consumption. “It’s difficult to measure overall sugar intake in the diet,” he says, “so we used sugary beverages as a proxy.”Will warning labels scare parents away from soda?
For the first study, researchers examined data, including magnetic resonance imaging (MRI) scans and cognitive testing results, from about 4,000 people enrolled in the Framingham Heart Study’s Offspring and Third-Generation cohorts. (These are the children and grandchildren of the original FHS volunteers enrolled in 1948.)
The researchers looked at people who consumed more than two sugary drinks a day of any type—soda, fruit juice, and other soft drinks—or more than three per week of soda alone. Among that “high intake” group, they found multiple signs of accelerated brain aging, including smaller overall brain volume, poorer episodic memory, and a shrunken hippocampus, all risk factors for early-stage Alzheimer’s disease. Researchers also found that higher intake of diet soda—at least one per day—was associated with smaller brain volume.
In the second study, the researchers, using data only from the older Offspring cohort, looked specifically at whether participants had suffered a stroke or been diagnosed with dementia due to Alzheimer’s disease. After measuring volunteers’ beverage intake at three points over seven years, the researchers then monitored the volunteers for 10 years, looking for evidence of stroke in 2,888 people over age 45, and dementia in 1,484 participants over age 60.
Here they found, surprisingly, no correlation between sugary beverage intake and stroke or dementia. However, they found that people who drank at least one diet soda per day were almost three times as likely to develop stroke and dementia.Will warning labels scare parents away from soda?
Although the researchers took age, smoking, diet quality, and other factors into account, they could not completely control for preexisting conditions like diabetes, which may have developed over the course of the study and is a known risk factor for dementia.
Diabetics, as a group, drink more diet soda on average, as a way to limit their sugar consumption, and some of the correlation between diet soda intake and dementia may be due to diabetes, as well as other vascular risk factors. However, such preexisting conditions cannot wholly explain the new findings.
“It was somewhat surprising that diet soda consumption led to these outcomes,” says Pase, noting that while prior studies have linked diet soda intake to stroke risk, the link with dementia was not previously known. He adds that the studies did not differentiate between types of artificial sweeteners and did not account for other possible sources of artificial sweeteners.
Pase says that scientists have put forth various hypotheses about how artificial sweeteners may cause harm, from transforming gut bacteria to altering the brain’s perception of sweet, but “we need more work to figure out the underlying mechanisms.”
Source: Boston University
Umbilical cord blood from human newborns boosts the brain function and cognitive performance of old mice, a new study shows.
Researchers identified a protein, abundant in human cord blood but decreasingly so with advancing age, that has the same effect when injected into the animals.
“To me it’s remarkable that something in your blood can influence the way you think.”
The findings could lead to new treatments for age-associated declines in mental ability.
“Neuroscientists have ignored it and are still ignoring it, but to me it’s remarkable that something in your blood can influence the way you think,” says Tony Wyss-Coray, professor of neurology and neurological sciences at Stanford University and a senior research career scientist at the Veterans Affairs Palo Alto Health Care System.
In an earlier study, Wyss-Coray’s lab showed that direct infusion of young mice’s plasma, the cell-free portion of blood, benefited old mice. Those benefits extended beyond biochemistry and physiology to actual performance on tests of memory and learning.
The new study, published in the journal Nature, marks the first demonstration that human plasma can aid older mice’s memory and learning, which researchers say would seem to increase the likelihood that it could have a similar beneficial effect in people. Also promising from a drug-development standpoint is the idea that a single protein appears largely capable of mimicking those benefits.
Comparing blood plasma from 19- to 24-year-olds, 61- to 82-year-olds, and umbilical cords, researchers identified age-associated changes in a number of proteins.
Investigators suspected these changes might affect the hippocampus, which in both mice and humans is critical for converting experiences into long-term memories. In particular, the hippocampus is essential for helping you remember spatial information, such as how to find your way back to the car you parked in a multilevel structure several hours ago, and information about autobiographical events, such as what you ate for breakfast.
For largely unknown reasons, the hippocampus is especially vulnerable to normal aging, Wyss-Coray says. “With advancing age, the hippocampus degenerates, loses nerve cells, and shrinks.” The capacity to learn and remember falters in lockstep. Hippocampal deterioration is also an early manifestation of Alzheimer’s disease.Stellar performance
To distinguish the effects of old, young, and “youngest” human blood on hippocampal function, researchers used immune-deficient laboratory mice that could be given repeated injections of human plasma without experiencing negative immune reactions. Experiments undertaken before injecting human plasma into the mice showed that, like their immune-competent peers, these mice’s hippocampal activity, integrity, and regenerative capacity dropped off in old age—indeed, a bit faster.
Old immune-deficient mice didn’t perform as well as younger ones on tests of memory and learning. One such test, the Barnes maze, employs a table, about 4 feet in diameter and 1.3 feet high, that is brightly lit and open to the surrounding environment—two factors that make mice feel insecure. The table is also full of holes, one of which is attached to a tube in which a scared mouse can find darkness and safety.Scientists want to grow new neurons in old brains
The other holes offer only a drop to the floor from a height that would not physically harm a mouse but is enough deter one. Which hole has a burrowing tube attached to it can change from one session to the next. Visual cues to its location can also transfer to help guide the mouse to the escape hole, memory permitting.
When the older mice received human umbilical-cord blood plasma every fourth day for two weeks, many measures of hippocampal function noticeably improved. Plasma from older people, on the other hand, didn’t help at all, while young-adult plasma induced an intermediate effect.
Further, older mice’s performance on the Barnes maze and other tests was stellar in comparison with mice of the same age who got injections of saline instead of plasma.So what made the difference?
Something in umbilical cord blood was making old brains act younger. To find out what it was, researchers gauged plasma-protein levels in humans and mice from different age groups, in search of proteins that the two species share in common and whose levels change similarly with age.Electromagnets act like a scalpel to improve memory
One protein in particular grabbed their attention: In a laboratory test designed to discern a substance’s ability to enhance nerve-cell activity in the brain, it triggered this activity to a great degree. The protein, called tissue inhibitor of metalloproteases 2, or TIMP2, belongs to a well-known family of four TIMPs that regulate the activity of other proteins whose function is to chop up yet other proteins occupying the matrix in which cells are embedded.
Injecting TIMP2 by itself into elderly mice largely duplicated the beneficial effects of umbilical-cord plasma. It even restored these mice’s nesting capacity: an instinctive penchant, largely lost in old age, for using available materials, such as cotton wads supplied by the researchers, to build nests in which mice typically prefer to sleep. But old mice that were given human cord plasma depleted of TIMP2 derived no learning and memory benefits. And administering TIMP2-neutralizing antibodies to young normal mice, who ordinarily perform well on memory tests, obliterated their prowess.
“TIMP2’s effects in the brain have been studied a little, but not much and not in aging,” says lead author Joseph Castellano, a former postdoctoral scholar who is now an instructor of neurology and neurological sciences.
“In our study, it mimicked the memory and learning effects we were getting with cord plasma. And it appeared to do that by improving hippocampal function.”
Stanford’s Office of Technology Licensing has filed for patents related to the findings in the study. Alkahest, a biotechnology company based in San Carlos, California, in which Castellano and Wyss-Coray hold equity and which Wyss-Coray cofounded, has licensed rights to this intellectual property.
The National Institute on Aging, the Jane Coffin Childs Foundation, the Simons Foundation, the US Department of Veterans Affairs, the Glenn Foundation for Medical Research, the Stanford Brain Rejuvenation Project, and Stanford’s Department of Neurology and Neurological Sciences funded the work.
Source: Stanford University
We tend to think salty food makes us thirsty, and that’s true in the short-term. But within 24 hours of increasing salt consumption, your body starts to conserve and produce water, making you less thirsty.
This counterintuitive discovery goes against more than 100 years of conventional scientific wisdom and may provide new insights into the Western epidemics of obesity, diabetes, and heart disease.
The findings, reported in two papers in the Journal of Clinical Investigation, shed new light on the body’s response to high salt intake and could provide an entirely new approach to these three major killer diseases.
According to the textbooks, the excretion of dietary salt inevitably leads to water loss into the urine and thereby reduces body water content. But that’s not what Jens Titze of Vanderbilt University and his team found. On the contrary, he says, “we showed the biological principle of salt excretion is water conservation and water production.”
It takes a lot of energy to conserve water in the face of salt excretion. To do it, the body either must take in more fuel or utilize its own energy stores and break down muscle mass. “This predisposes to overeating,” Titze says. “The resulting metabolic response looks a lot like diabetes.”Cosmonaut urine
Titze, associate professor of medicine and of molecular physiology and biophysics at Vanderbilt, has been probing the mysteries of salt and water metabolism since he was a medical student at Freie Universität Berlin (Free University of Berlin).
In the mid-1990s he began conducting long-term sodium balance studies in Russian cosmonauts who were participating in a human space flight simulation program at a research facility in Moscow in preparation for a potential manned spaceflight to Mars.Crew members try out their spacesuits during a simulated mission to Mars at the Russian Academy of Sciences’ Institute of Biomedical Problems in Moscow. Their training included a controlled feeding study to measure the long-term effects of a high-salt diet. (Credit: IBMP and the German Aerospace Center)
When the simulation program resumed a decade later, Titze—then a faculty member at the University of Erlangen-Nuremberg—continued his studies, this time carefully controlling what the men ate and measuring how much salt and water they excreted in their urine.
Between 2009 and 2011, his team studied four men during a 105-day pre-flight phase and six others during the first 205 days of a 520-day phase that simulated a full-length manned mission to Mars and back.
The amount of dietary salt varied between 6, 9, and 12 grams a day. Russian scientist Natalia Rakova, first author of the clinical study, made sure the men ate every crumb of their meals and collected every drop of urine every day. Rakova is now at the Charité Medical Faculty and Max-Delbrück Center for Molecular Medicine in Berlin.
Titze came to Vanderbilt in 2011. In 2013 the scientists reported that sodium excretion occurred not on a daily basis but fluctuated with a weekly rhythm. That observation, which went against the prevailing dogma, suggested sodium was stored in the body.Space changed gut bacteria of these twin astronauts
Levels of the hormones aldosterone, which regulates sodium excretion, and cortisol, a glucocorticoid that helps break down glucose and fat for fuel, also fluctuated weekly.
Surprisingly, when dietary salt went from 6 to 12 grams a day, the men drank less water, not more. That suggested they must be conserving and producing water. But how?Muscle wasting
In a subsequent study in mice, the researchers confirmed what they’d suspected in humans. High salt induces a catabolic state driven by glucocorticoids. The liver breaks down muscle protein and converts it into urea.
Urea is usually thought of as a waste product that is eliminated into the urine. Titze’s group now shows this nitrogen-containing compound creates a driving force that brings the water back into the body instead of letting it follow the salt into the urine.
The kidneys thus act as a biological barrier for water conservation to prevent dehydration when salt intake is high.
Traditionally, salt, and water balance has focused on the kidney. This study suggests the liver and skeletal muscle also play a role in regulating salt and water metabolism, says Kento Kitada, research fellow in Titze’s lab and first author of the second study.
Muscle wasting is a high price to pay for avoiding dehydration, adds Steffen Daub, a visiting research fellow in the lab and co-first author with Kitada of the second paper. The alternative is bringing in more fuel—eating more. That may be why the men in the study complained they were hungry when their salt intake was high.How your brain knows when you’re thirsty
Water conservation in response to a high-salt diet may have pathological consequences. Increased levels of glucocorticoids are an independent risk factor for diabetes, obesity, osteoporosis, and cardiovascular disease.
“We have always focused on the role of salt in arterial hypertension. Our findings suggest that there is much more to know—a high salt intake may predispose to metabolic syndrome,” Titze says.
Scientists from the Max-Delbrück Center in Berlin and the German Aerospace Center in Cologne also contributed to the work. Support for the studies came largely from the German Federal Ministry for Economics and Technology, the Interdisciplinary Center for Clinical Research Junior Research Group in Erlangen, and from the American Heart Association and National Institutes of Health.
Source: Vanderbilt University
Scientists have published the most detailed geological history to date for a region of Mars known as Northeast Syrtis Major. The spot is high on NASA’s list of potential landing sites for its next Mars rover, which will launch in 2020.
The region is home to a striking mineral diversity, including deposits that indicate a variety of past environments that could have hosted life. Using the highest resolution images available from NASA’s Mars Reconnaissance Orbiter, the study maps the extent of those key mineral deposits across the surface and places them within the region’s larger geological context.
“When we look at this in high resolution, we can see complicated geomorphic patterns and a diversity of minerals at the surface that I think is unlike anything we’ve ever seen on Mars,” says Mike Bramble, a PhD student at Brown University who led the study in the journal Icarus. “Within a few kilometers, there’s a huge spectrum of things you can see and they change very quickly.”A detailed map shows the the various geologic units exposed at Northeast Syrtis.
If NASA ultimately decides to land at Northeast Syrtis, the new history would help provide a roadmap for the rover’s journey.
“This is a foundational paper for considering this part of the planet as a potential landing site for the Mars2020 rover,” says Jack Mustard, a professor of earth, environmental and planetary sciences and a coauthor of the paper. “This represents an exceptional amount of work on Mike’s part, really going into the key morphologic and spectroscopic datasets we need in order to understand what this region can tell us about the history of Mars if we explore it with a rover.”Eight potential landing sites for the Mars rover. (Credit: NASA/JPL-Caltech)
Northeast Syrtis sits between two giant Martian landforms—an impact crater 2,000 kilometers in diameter called the Isidis Basin, and a large volcano called Syrtis Major. The impact basin formed about 3.96 billion years ago, while lava flow from the volcano came later, about 3.7 billion years ago. Northeast Syrtis preserves the geological activity that occurred in the 250 million years between those two events. Billions of years of erosion, mostly from winds howling across the region into the Isidis lowlands, have exposed that history on the surface.
Within Northeast Syrtis are the mineral signatures of four distinct types of watery and potentially habitable past environments. Those minerals had been detected by prior research, but the new map shows in detail how they are distributed within the region’s larger geological context. That helps constrain the mechanisms that may have formed them, and shows when they formed relative to each other.
The lowest and the oldest layer exposed at Northeast Syrtis has the kind of clay minerals formed when rocks interact with water that has a fairly neutral pH. Next in the sequence are rocks containing kaolinite, a mineral formed by water percolating through soil. The next layer up contains spots where the mineral olivine has been altered to carbonate—an aqueous reaction that, on Earth, is known to provide chemical energy for bacterial colonies. The upper layers contain sulfate minerals, another sign of a watery, potentially life-sustaining environment.
Understanding the relative timing of these environments is critical, Mustard says. They occurred around the transition between the Noachian and Hesperian epochs—a time of profound environmental change on Mars.Busted moon could put rings around Mars
“We know that these environments existed near this major pivot point in Mars history, and in mapping their context we know what came first, what came next and what came last,” Mustard says. “So now if we’re able to go there with a rover, we can sample rock on either side of that pivot point, which could help us understand the changes that occurred at that time, and test different hypotheses for the possibility of past life.”
And finding signs of past life is the primary mission of the Mars2020 rover. NASA has held three workshops in which scientists debated the merits of various landing targets for the rover. Northeast Syrtis has come out near the top of the list at each workshop. Last February, NASA announced that the site is one of the final three under consideration.
Mustard and Bramble hope this latest work might inform NASA’s decision, and ultimately help in planning the Mars2020 mission.
“As we turn our eyes to the next target for in situ exploration on the Martian surface,” the researchers say, “no location offers better access of the gamut of geological processes active at Mars than Northeast Syrtis Major.”
Source: Brown University
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A warming climate has melted northern Canada’s Kaskawulsh Glacier so much that the glacier’s “retreat” has changed the course of a nearby river, new research shows.
Last spring, the glacier’s retreat triggered the geologic event at relatively breakneck speed. The toe of ice that was sending meltwater toward the Slims River and then north to the Bering Sea retreated so far that the water changed course, joining the Kaskawulsh River and flowing south toward the Gulf of Alaska.
This capture of one river’s flow by another, documented in a study published in Nature Geoscience, is the first known case of “river piracy” in modern times.Kaskawulsh River. See the full panoramic image. (Credit: Jim Best/U. Illinois) River piracy
“Geologists have seen river piracy, but nobody to our knowledge has documented it happening in our lifetimes,” says lead author Dan Shugar, a geoscientist at the University of Washington. “People had looked at the geological record—thousands or millions of years ago—not the 21st century, where it’s happening under our noses.”
River piracy, also known as stream capture, can happen due to tectonic motion of Earth’s crust, landslides, erosion or, in this case, a change in a glacial dam. The new study documents one of the less-anticipated shifts that can occur in a changing climate.
Shugar and coauthors Jim Best at the University of Illinois and John Clague at Canada’s Simon Fraser University had planned fieldwork last summer on the Slims River, a geologically active system that feeds Kluane Lake in the Yukon. When they arrived in August, the river was not flowing. River gauges show an abrupt drop over four days from May 26 to 29, 2016.
By late summer, “there was barely any flow whatsoever. It was essentially a long, skinny lake,” Shugar says. “The water was somewhat treacherous to approach, because you’re walking on these old river sediments that were really goopy and would suck you in. And day by day we could see the water level dropping.”The receding toe of Kaskawulsh Glacier is visible at the bottom. Kluane Lake is at the top of the 2016 image. Water now flows east and then south via the Kaskawulsh River. (Credit: European Space Agency) This September 2, 2016 aerial photo shows the meltwater stream along the toe of Kaskawulsh Glacier, seen on the left, that is diverting fresh water from one river to the other. (Credit: Dan Shugar/U. Washington Tacoma)
The research team puzzled about what to do next. They got permission to use their mapping drone to create a detailed elevation model of the glacier tongue and headwater region. The resulting paper is a geological postmortem of the river’s disappearance.
“Our study shows there may be other underappreciated, unanticipated effects of glacial retreat.”
“For the last 300 years, Slims River flowed out to the Bering Sea, and the smaller Kaskawulsh River flowed to the Gulf of Alaska. What we found was the glacial lake that fed Slims River had actually changed its outlet,” Shugar says.
“A 30-meter (100-foot) canyon had been carved through the terminus of the glacier,” he continues. “Meltwater was flowing through that canyon from one lake into another glacial lake, almost like when you see champagne poured into glasses that are stacked in a pyramid.”
That second lake drains via the Kaskawulsh River in a different direction than the first. The situation is fairly unique, Shugar says, since the glacier’s toe was sitting on a geologic divide.How quickly can glaciers grow (and melt)?
Clague began studying this glacier years ago for the Geological Survey of Canada. He observed that Kluane Lake, which is Yukon’s largest lake, had changed its water level by about 40 feet (12 meters) a few centuries ago. He concluded that the Slims River that feeds it had appeared as the glacier advanced, and a decade ago predicted the river would disappear again as the glacier retreated.
“The event is a bit idiosyncratic, given the peculiar geographic situation in which it happened, but in a broader sense it highlights the huge changes that glaciers are undergoing around the world due to climate change,” Clague says.The costs of climate change
The geologic event has redrawn the local landscape. Slims River crosses the Alaska Highway, and its banks were a popular hiking route. Now that the riverbed is exposed, Dall sheep from Kluane National Park are making their way down to eat the fresh vegetation, venturing into territory where they can legally be hunted.
With less water flowing in, Kluane Lake did not refill last spring, and by summer 2016 was about 3 feet (1 meter) lower than ever recorded for that time of year. Waterfront land, which includes the small communities of Burwash Landing and Destruction Bay, is now farther from shore. As the lake level continues to drop researchers expect this will become an isolated lake cut off from any outflow.
On the other hand, the Alsek River, a popular whitewater rafting river that is a UNESCO world heritage site, was running higher last summer due to the addition of the Slims River’s water.
Shifts in sediment transport, lake chemistry, fish populations, wildlife behavior, and other factors will continue to occur as the ecosystem adjusts to the new reality, Shugar says.
“So far, a lot of the scientific work surrounding glaciers and climate change has been focused on sea-level rise,” Shugar says. “Our study shows there may be other underappreciated, unanticipated effects of glacial retreat.”Coal blamed for retreat of Europe’s glaciers in 1860s
The Kaskawulsh Glacier is retreating up the valley because of both readjustment after a cold period centuries ago, known as the Little Ice Age, and warming due to greenhouse gases. A technique published in 2016 by coauthor Gerard Roe shows a 99.5 percent probability that this glacier’s retreat is showing the effects of modern climate change.
“I always point out to climate-change skeptics that Earth’s glaciers are becoming markedly smaller, and that can only happen in a warming climate,” Clague says.
Other coauthors are from the University of British Columbia, the University of Colorado, and the University of Ottawa. The University of Washington Royalty Research Fund, Parks Canada, Yukon Geological Survey, the Natural Sciences and Engineering Research Council of Canada, the University of Ottawa, and the University of Illinois funded the research.
Source: University of Washington
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Mindfulness courses have less effect on the attitudes and emotions of men than on those of women, new research suggests.
In a study of a scholarly course on mindfulness that also included meditation labs, researchers found that the practice on average significantly helped women overcome “negative affect”—a downcast mood—but did not help men.
The finding, the authors say, should call more attention to considering gender as a potential factor in assessing mindfulness efficacy.
More women than men engage in mindfulness meditation, the practice of intentionally and non-judgmentally directing one’s attention to present sensations and feelings, says Willoughby Britton, assistant professor of psychiatry and human behavior and of behavioral and social sciences at Brown University.
“I wouldn’t be surprised if this is a widespread phenomenon that researchers hadn’t bothered to investigate.”
There hasn’t been a prevailing notion in the research literature that the practice affects men and women differently. Yet the data Britton and her coauthors present in a new paper in Frontiers in Psychology show a clear gender difference in outcomes for mood.
“That was the surprising part,” Britton says. Since this study, though, she has found the same pattern in two other studies under review for future publication. “I wouldn’t be surprised if this is a widespread phenomenon that researchers hadn’t bothered to investigate.”
On the other hand, Britton adds, it was encouraging to see a clear benefit for women, who are generally more vulnerable to negative affect and depression, she notes.
“Emotional disorders like depression in early adulthood are linked to a litany of negative trajectories that further disadvantage women, such as poor academic performance, school drop-out, early pregnancy, and substance abuse,” she says.
“The fact that a college course could teach women skills to better manage negative affect at this early age could have potentially far-reaching effects on women’s lives.”
Co-lead author Rahil Rojiani, a medical student at Yale University, says he hopes the study will narrow disparities in mental health care.
“The gender gap in mental health has been inadequately targeted and often only within the standard medical arsenal of pharmacological treatment,” Rojiani says. “Our study is one of the first to explore the effects of mindfulness across gender.”Men vs. women
The study measured changes in affect, mindfulness, and self-compassion among 41 male and 36 female students over the course of a full, 12-week academic class on mindfulness traditions with papers, tests, and presentations that also included an experiential component of three hour-long meditation labs a week.
Coauthor Harold Roth, professor of religious studies, taught the labs, which included about 30 minutes per session of specific contemplative practice from Buddhist or Daoist traditions. Mindfulness has become popular on college campuses, Britton says, as students and administrators look to it as a potential way of helping students manage stress or depression.
For this study, students filled out questionnaires at the beginning and the end of the class. Over the course of the study, the average student had engaged in more than 41 hours of meditation in class and outside. There was no statistically significant difference in the amount of meditation practice by gender. Men and women also entered the class with no difference in their degree of negative affect.
As a group, the 77 students also did not leave the class showing a significant difference in negative affect. That’s because while women showed a significant 11.6 percent decline on the survey’s standardized score (which is a positive psychological outcome), men showed a non-significant 3.7 percent increase in their scores.Brains of veterans with PTSD changed after mindfulness training
Alongside those changes in affect, each gender showed progress in skills taught as part of meditation. Both genders gained in several specific mindfulness and self-compassion skills and their overall scores increased significantly. That finding shows that the classes were effective in teaching the techniques, though women made greater gains than men on four of five areas of mindfulness.
When the researchers dug further into the data, they saw that in women several of the gains they made in specific skills correlated with improvements in negative affect.
“Improved affect in women was related to improved mindfulness and self-compassion skills, which involved specific subscales for approaching experience and emotions with non-reactivity, being less self-critical and more kind with themselves, and over-identifying less with emotions,” the authors write.
Meanwhile, among men, only one of the specific skills was associated with better affect.
“To the extent that affect improved, changes were correlated with an improved dimension of mindfulness involving the ability to identify, describe, and differentiate one’s emotions,” they write.A new hypothesis on mindfulness
Britton says the results suggest a new hypothesis, which is that mindfulness regimens, at least as they are often structured, may be better attuned to addressing the ways that women typically process emotions than the ways that men often do. Mindfulness guides practitioners to focus on and acknowledge feelings but to do so in a non-judgmental and non-self-critical way.Men prefer pain to being alone with their thoughts
“The mechanisms are highly speculative at this point, but stereotypically, women ruminate and men distract,” Britton says. “So for people that tend to be willing to confront or expose themselves or turn toward the difficult, mindfulness is made for [improving] that. For people who have been largely turning their attention away from the difficult, to suddenly bring all their attention to their difficulties can be somewhat counterproductive.”
“While facing one’s difficulties and feeling one’s emotions may seem to be universally beneficial,” he continues, “it does not take into account that there may be different cultural expectations for men and women around emotionality.”
If that hypothesis is supported in further research, the findings may yield an important strategy for the designers of mindfulness curricula. For women, the message may be to stay the course, but for men the best idea may be to tailor mindfulness differently.
“Mindfulness is a little bit like a drug cocktail—there are a lot of ingredients and we’re not sure which ingredients are doing what,” Britton says. “But I think a strategy of isolating potential ‘active ingredients’ and using slightly more innovative designs to tailor to the needs of different populations is what’s called for.”
For fellow mindfulness researchers, Britton says, the study emphasizes a benefit to accounting for gender. Had she not done so in this study, she would have reported a null effect on affect when in fact women benefitted significantly. At the same time, if the study population had been heavily skewed toward women rather than more balanced, she might have measured a stronger benefit that would have been improperly extrapolated to men.
The National Institutes of Health, the Mind and Life Institute, the Lenz Foundation, the Hershey Foundation, and the Brown University Contemplative Studies Initiative funded the research.
Source: Brown University
A new survey finds that two-thirds of Americans say they would like to ride in or operate their own airborne vehicle.
Forty-one percent of adult respondents to an online survey are “very interested” in riding in a fully autonomous (self-driving and self-flying) flying car, say researchers. That compares to 26 percent of those who are “very interested” in operating the aerocar themselves after obtaining an appropriate pilot license.
“Until recently, flying cars have existed primarily in the realm of science fiction, although patents for such vehicles extend to the early years of aviation,” says Michael Sivak, a research professor at the University of Michigan Transportation Research Institute. “However, recently there has been a rapid increase in interest in flying cars from companies ranging from large, international manufacturers to a variety of startups.
“In addition to major technological, traffic-control, and licensing issues that still will need to be addressed, a big unknown is what consumers think of the concept of flying cars…”
In their study, Sivak and colleague Brandon Schoettle found that more than 60 percent of respondents are “very concerned” with the overall safety of flying cars and with their performance in congested airspace and poor weather.Will self-driving cars make us queasy?
Despite these concerns, most Americans would still ultimately like to use flying cars, the researchers say. About three-fourths of the respondents cited shorter travel time as the main reason, while less than 10 percent said fewer crashes, better fuel economy, or lower emissions were the most likely benefits of flying cars.
Other findings include:
Source: University of Michigan
Preventive visits to the dentist for children under two may not reduce the need for more care later, a new study suggests.
Early preventive dental care was associated with more frequent subsequent treatment for tooth decay, more visits, and more spending on dental care, compared with no early preventive dental care.
However, preventive care from primary care providers was not significantly associated with tooth decay-related treatment or expenditures.
“We don’t think that going to the dentist is somehow causing these kids to have tooth decay,” says Michael Morrisey, professor and head of the health policy & management department at the Texas A&M School of Public Health. “At the same time, we want parents to know that early checkups probably won’t reduce the need for future dental procedures like filings.”
The American Academy of Pediatrics, American Dental Association, and American Academy of Pediatric Dentistry recommend children receive dental care once baby teeth begin to appear.
For the study, published in JAMA Pediatrics, researchers analyzed Medicaid data from 19,658 children in Alabama, 25.8 percent of whom received preventive dental care from a dentist before age 2. The average follow-up time was almost four years.
Compared with similar children without early preventive dental care, those receiving such care from a dentist had more frequent tooth decay-related treatment (20.6 percent versus 11.3 percent) and a higher rate of visits and higher annual dental expenditures ($168 versus $87) later in childhood.
The researchers stress the study has limitations. Because the study only included children on Alabama’s Medicaid, the publicly funded health care program for low-income Americans, children elsewhere may show different trends. Further, researchers didn’t examine oral health behaviors such as teeth brushing or environmental ones like water fluoridation.Babies with eczema may have tooth decay later
“It’s a bit surprising that we found so few benefits, especially since parents are routinely encouraged to take their children for early dental checkups,” Morrisey says. “Still, it is possible that even though the dentist visits were coded as preventive, the babies and toddlers already had some sign or risk factor of tooth decay. To really answer the question of efficacy of early routine checkups, one should do randomized clinical trials.”
It also wasn’t clear from the data analyzed in the study what each preventive care visit involved. Typically, the main service at these visits is a topical fluoride varnish, but children who already have high levels of tooth decay may continue to get new decay even when the varnish is applied. These visits may also serve as an opportunity for parents to ask questions about how best to teach their children good oral care habits.
“All I can recommend is that parents follow the advice of their child’s dentist or health care provider,” Morrisey says. “We examined the data in the aggregate, but only those seeing the individual child will be able to determine what’s best for him or her.”
Additional researchers from Texas A&M and the University of Alabama at Birmingham are coauthors of the study.
Source: Texas A&M University
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A recent survey finds that half of pot users have seen marijuana ads, either traditional or online.
“Advertising can be powerful,” says first author of the study Melissa J. Krauss, a research statistician in the psychiatry department at the Washington University School of Medicine in St. Louis. “That’s why we’re concerned that so many young adults are seeing ads for marijuana. It’s also likely that younger, more vulnerable kids are seeing ads, too.”Hear Krauss explain the findings: https://www.futurity.org/wp/wp-content/uploads/2017/04/Krauss-pot-ads-.mp3
Marijuana is now legal in more than half of US states. Some states allow medicinal use, while eight states have legalized recreational use.
In an online survey of 742 young adults ages 18-34 who reported recent marijuana use, the researchers found 54 percent had seen or even sought out marijuana advertising in the previous month.
Laws regarding marijuana advertising vary from state to state, but most of those who encountered pot advertising said they saw the ads online, either on websites or social media. Even where there are restrictions on ads, online advertising easily crosses state lines.
Facebook also prohibits ads for marijuana. “But you can go on Facebook and discover pretty quickly that ads and information about dispensaries are there,” Krauss says.More legal pot, but fewer teen pot problems
Marijuana use can develop into a disorder. According to the National Institute on Drug Abuse, about 30 percent of those who use marijuana have some level of a marijuana use disorder, which can be associated with dependence on the drug.
Although the survey group only included people who said they used pot and was not a nationally representative sample, Krauss calls it alarming that so many people had seen ads for pot, even in places where such ads are supposed to be prohibited.
People who said they actively had sought out marijuana advertising tended to be users of medicinal marijuana products.
“Individuals who seek out ads also are more likely to use novel marijuana products, such as edibles and concentrates, and are more likely to be heavy users,” Krauss says.
The people least likely to be exposed to marijuana ads were those who used pot recreationally and lived in states where marijuana use is illegal. These users were more likely to smoke pot rather than use edibles or concentrates.
“As more states legalize marijuana, we should be vigilant about ads that promote the drug, especially if those ads are aimed at young people,” Krauss says. “We need to protect those who are most vulnerable to the consequences of marijuana use and abuse.”
The research appears in the journal Drug and Alcohol Dependence. The National Institute on Drug Abuse of the National Institutes of Health supported the work.
Virtual reality could be useful not only for detecting balance impairments early, but perhaps also for reversing those impairments and preventing falls.
Every year, falls lead to hospitalization or death for hundreds of thousands of elderly Americans. Standard clinical techniques generally cannot diagnose balance impairments before they lead to falls.
In a study in Scientific Reports, a research team led by Jason R. Franz, assistant professor of biomedical engineering at the University of North Carolina at Chapel Hill, used a novel VR system to create the visual illusion of a loss of balance as study participants walked on a treadmill.
By perturbing their sense of balance in this way and recording their movements, Franz’s team was able to determine how the participants’ muscles responded. In principle, a similar setup could be used in clinical settings to diagnose balance impairments, or even to train people to improve their balance while walking.
“The participants know they aren’t really swaying, but their brains and muscles automatically try to correct their balance anyway.”
“We were able to identify the muscles that orchestrate balance corrections during walking,” Franz says. “We also learned how individual muscles are highly coordinated in preserving walking balance. These things provide an important roadmap for detecting balance impairments and the risk of future falls.”
Young and healthy adults rely predominantly on the mechanical “sensors” in their feet and legs to give them an accurate sense of body position. So, healthy people usually have no trouble walking in the dark or with their eyes closed.Device could buzz feet to prevent falls
This sense of proprioception declines in the elderly, as well as in people who have neurodegenerative diseases, such as multiple sclerosis, leading to a much greater reliance on visual cues to maintain balance. In their study, Franz and colleagues chose to use a VR-based method to perturb the visual perception of balance.
The subjects walked on a treadmill in front of a large, curved screen depicting a moving hallway.
“As each person walked, we added lateral oscillations to the video imagery, so that the visual environment made them feel as if they were swaying back and forth, or falling,” Franz says. “The participants know they aren’t really swaying, but their brains and muscles automatically try to correct their balance anyway.”The virtual reality lab at UNC. (Credit: UNC/NC State department of biomedical engineering)
In a setup like those in Hollywood motion-capture animation studios, Franz and his team used 14 cameras to record the positions of 30 reflecting markers on the legs, back, and pelvis of each subject. This allowed them to see, in detail, how the specific muscle groups that control postural sway and foot placement worked to correct a perceived loss of balance.
In response to the visual perturbations, the subjects took wider and shorter steps, as expected. And their head and trunk swayed further sideways with each step. The variability of these measures—their tendency to change from one step to the next—increased much more strikingly. Electrodes attached to the skin of the subjects also revealed coordinated electrical activity among the muscles that control postural sway and foot placement, including the gluteus medius, external oblique, and erector spinae.
“These findings give us important insights into the detailed mechanisms of walking balance control,” Franz says.
The data also provide key reference measurements that could be used in future clinical procedures to detect balance impairments before they cause people to fall.Falls are not inevitable for older adults
Franz and his team have ongoing studies in elderly people and plans for studies in people with multiple sclerosis to help develop early-detection procedures. In their earlier work, they have shown that using this VR setting can identify age-related balance deficits that are not otherwise apparent during normal walking.
“We think there’s a big opportunity to use visual perturbations in a VR setting to reveal balance impairments that would not be detected in conventional testing or normal walking,” Franz says. “The key is to challenge balance during walking, to tease out those impairments that exist under the surface.”
Franz and his colleagues also are examining the potential of their VR setup as a physical therapy tool to teach balance-impaired people how to improve their balance and avoid falls.
“Early work in our lab suggests it’s possible to use these visual perturbations to train a person’s balance control system to respond better to imbalance that occurs in daily living,” Franz says.
The National Center for Advancing Translational Sciences funded this research.
Source: UNC-Chapel Hill
Spermidine—a compound in foods like aged cheese, mushrooms, soy products, legumes, corn, and whole grains—may prevent liver fibrosis and hepatocellular carcinoma, the most common type of liver cancer.
There is also some evidence that it may prolong lifespan, according to a study in the journal Cancer Research.
Researchers gave animal models an oral supplement of spermidine and found that they lived longer and were less likely than untreated individuals to have liver fibrosis and cancerous liver tumors, even when predisposed for those conditions.
“It’s a dramatic increase in lifespan of animal models, as much as 25 percent,” says Leyuan Liu, assistant professor at the Texas A&M Institute of Biosciences and Technology’s Center for Translational Cancer Research. “In human terms, that would mean that instead of living to about 81 years old, the average American could live to be over 100.”
The trouble is that people would need to begin ingesting spermidine from the time they begin eating solid food to get this kind of significant improvement in their lifespans; those animal models treated later only saw a 10 percent increase in longevity. Still, it may be the most sustainable option scientists have found yet.
“Only three interventions—severely cutting the number of calories consumed, restricting the amount of methionine (a type of amino acid found in meat and other proteins) in the diet, and using the drug rapamycin—have been shown to truly prolong the lifespans of vertebrates, but eating less and not eating meat will not be welcomed by general population, while rapamycin has shown to suppress the human immune system,” Liu says. “Therefore, spermidine may be a better approach.”
“Just think: if we added spermidine to every bottle of beer, it might balance out the alcohol and help protect the liver.”
Long-term spermidine ingestion might be possible for humans if it can be eventually made into a supplement and shown to be safe. Liu is optimistic that this might be the case. “Spermidine is a product naturally found in food, so we hope it would have minimal side effects,” he says. “The next steps would be human clinical trials to determine safety and efficacy.”
Spermidine is a type of compound called a polyamine and was first isolated from semen, which explains its name. It likely works to prevent cancer by enhancing MAP1S-activated autophagy, or the cells’ self-eating behavior: The benefits of spermidine disappear when MAP1S isn’t available.
This builds off Liu’s earlier work, which indicated that autophagy—or the lack thereof—plays a role in cancer and premature aging. Damaged cells due to defective autophagy can go on to replicate and become tumors or cause other problems. Spermidine can prevent this process. There is also some evidence that it might improve cardiovascular health.Can bacteria in yogurt calm your anxiety?
Even if people didn’t begin taking spermidine until later in life, they still might be able to get these liver and heart benefits. The animal models exposed to spermidine showed reductions in both liver lesions and intensity of liver fibrosis, a condition that often leads to liver cancer.
Liu has an idea about how to incorporate the compound, similar to how folic acid has been added to most grain products to prevent neural tube defects. “Just think: if we added spermidine to every bottle of beer, it might balance out the alcohol and help protect the liver,” he says.
Still, Liu urges caution, as these results are preliminary and only—as of now—in animal models. “It’s still early,” he says, “but perhaps one day this approach will provide a novel strategy to prolong lifespans, prevent or reverse liver fibrosis, and prevent, delay, or cure hepatocellular carcinoma in humans.”
Source: Texas A&M University
Researchers are working to digitally preserve the bodies of lemurs that have died so future students and scientists might learn more about lemur anatomy—and “virtually dissect” them.
Almost all of the roughly 100 species of lemurs are facing extinction in the wild due to logging, mining, hunting, and slash-and-burn agriculture. Which is why, when an animal at the Duke University Lemur Center dies from illness, injury, or old age, a licensed veterinarian performs a postmortem exam within 24 hours of death, organs are removed, and tissue samples are collected so that other researchers can make use of them.
Cadavers of each species go into storage freezers or are preserved in formalin—not for ghoulish curiosity, but so that years from now their bodies could be still be useful for research and education.In 2013, Skimmer, a pygmy slow loris, died at the age of 19. Now, her body has been preserved with help from an X-ray imaging technique called micro-computed tomography. (Credit: Duke University)
And though these animals are gone, their bodies are now being preserved for present and future generations with help from an X-ray imaging technique called micro-computed tomography (microCT).
Soon, anyone will be able to go online to MorphoSource.org and get 3D views of the internal anatomy of dozens of lemurs and other rare and endangered prosimian primates, in micrometer detail, without disturbing the original specimens.
“Even when they’ve passed, these animals continue to contribute valuable scientific data,” says former Duke graduate student Gabe Yapuncich, who has been leading the effort to scan the specimens with assistant professor Doug Boyer.
Yapuncich got the idea for the project while earning his doctorate in evolutionary anthropology. He was scanning the skeletal remains of present-day primates to see if certain foot bone measurements could help to reconstruct how much their extinct relatives might have weighed.
Researchers can learn about many aspects of primate biology from fossils, but most fossil specimens consist of isolated teeth or fragments of bones. Complete or even partial skeletons are rare.
“It seemed like a waste just to scan the foot and send it back,” Yapuncich says. “Once I had a specimen on loan, I tended to scan the whole thing.”Inside the scanner
Yapuncich demonstrated how the technology works at Duke’s Shared Materials Instrumentation Facility. A giant lead-lined box there looks like an airport security scanner. Inside, a Styrofoam cooler filled with dry ice contains the frozen remains of Beauty, a female bamboo lemur who died in 1985.
The microCT scanner blasts a cone-shaped beam of X-rays at the cooler as it spins slowly on a rotating platform. The X-rays that pass through Beauty’s body hit a detector on the back wall, which records a snapshot.
The scanner takes thousands of snapshots for each full rotation. The data go to a computer, which uses the images to reconstruct two-dimensional cross sections of Beauty’s insides, and these are stacked like slices of bread into a 3D model.You can 3D-print these free scans of fish
Yapuncich peers at the result on a nearby computer screen. It’s a 3D close-up of Beauty’s head built from 1,900 cross-sectional images.
With the click of a mouse, he digitally dissects away Beauty’s fur, skin, and soft tissue to reveal the skeleton underneath in stunning, three-dimensional detail. He can also look at any 2D slice to see internal structures in cross section.
The Duke Lemur Center is committed to studying lemurs without harming them. Imaging cadavers makes it possible to perform “virtual” dissections that would never be allowed on living animals.
With standard microCT researchers can visualize hard tissues such as bones and teeth, but by using special iodine-based stains, they can also see soft tissues such as muscles, nerves, and blood vessels in the deceased animals.
Yapuncich has scanned the remains of more than 100 animals so far. A fat-tailed dwarf lemur named Jonas is one of them. When he died in 2015 at age 29, suffering from cataracts and other signs of age, he was the oldest of his kind. The scan shows his tail curled around his body, the roughly two dozen tail bones neatly lined up one after the other.
“If you go to a museum collection, the tail vertebrae are just a bunch of bones in a box,” Yapuncich says.Protecting the specimens
The Duke Lemur Center fields dozens of cadaver requests from researchers each year. But these rare and fragile specimens can only be examined so many times using traditional methods. Repeated shipping and handling may expose them to damage and freeze-thaw cycles that would inevitably speed their decay.
By creating high resolution 3D scans and putting them online, researchers hope to reduce destructive sampling and insure the availability of specimens for future study.
“There aren’t that many available,” says Duke R&D engineer and microCT specialist Justin Gladman. “If one researcher dissects and destroys one, the next researcher can’t do anything with it.”
“By scanning them in the microCT and creating these beautiful 3D models, we can digitize the specimens and share them online,” Gladman says. “Instead of being locked in a museum drawer, they’re freely available.”Lemur life after death
In the digital afterlife, Merlin’s bony appendages are no longer nimble but still intact.
He was one of four of the fewer than 60 endangered aye-ayes living in captivity worldwide that died suddenly over 36 hours at the Duke Lemur Center in October 2016. Staff and researchers were devastated.
The culprit, tests later revealed, was a natural toxin found in avocados, not previously known to be harmful to lemurs, which damaged their heart muscles.
In assistant professor Doug Boyer’s lab on Science Drive, recent Duke graduate Darbi Griffith uses software to stitch together nearly 3,000 2D images of Merlin into a 3D rendering.
Merlin was very popular with lemur center staff, and often enjoyed using his incredibly slender and dexterous middle finger to gently tease mealworms from his keepers’ closed fists.
The 3D volume rendering shows his body cloaked in skin and muscle. With a click his flesh fades away, and Griffith can zoom in on Merlin’s skull to examine the complex wear patterns on his teeth, or peer inside his cranial cavity to estimate the size and shape of his brain.Scientists create ‘virtual brains’ from tiny primate skulls
Griffith has uploaded these 3D images to an online database Boyer created called MorphoSource. Because the digitization is ongoing the Lemur Center scans haven’t been made publicly available yet, but when they are, visitors to MorphoSource will be able to compare Merlin to other individuals, or measure anatomical variation across species.
Anyone will be able to browse the specimens, measure them, download the raw data, and even create their own 3D lemur models, both of bodies and skeletons, on a 3D printer.
“It’s the largest collection of 3D lemur scans. That’s pretty cool,” Griffith says.
Grants from the National Science Foundation supported this research.
Source: Duke University
Babies cry more in Britain, Canada, and Italy, than the rest of the world, according to a universal chart for normal crying in babies during the first three months of life.
A new meta-analysis of studies involving almost 8,700 infants—in countries including Germany, Denmark, Japan, Canada, Italy, the Netherlands, and the UK—calculated the average of how long babies fuss and cry per twenty-four hours across different cultures.
The findings suggest that, on average, babies cry for around two hours per day in the first two weeks. Crying generally peaks at around two hours fifteen minutes per day at six weeks—and reduces gradually to an average of 1 hour 10 minutes by the twelve week mark.
However, some infants cry as little as 30 minutes—and others cry for more than five hours—in a 24-hour period.
The highest levels of colic were found in the UK (28 percent of infants at 1-2 weeks), Canada (34.1 percent at 3-4 weeks), and Italy (20.9 percent at 8-9 weeks.
In contrast, the lowest colic rates were seen in Denmark (5.5 percent at 3-4 weeks) and Germany (6.7 percent at 3-4 weeks).
Colic is defined as crying more than 3 hours a day for at least 3 days a week. The current definitions for determining whether a baby is crying too much and suffering from colic are the Wessel criteria, which were formulated in the 1950s.
As childcare and the family unit has largely transformed over the last half century and across different cultures, new universal guidelines were needed for modern parents and health professionals to assess normal and excessive levels of crying in babies.Your baby’s cry can rattle your brain
“Babies are already very different in how much they cry in the first weeks of life—there are large but normal variations. We may learn more from looking at cultures where there is less crying and whether this may be due to parenting or other factors relating to pregnancy experiences or genetics,” says Dieter Wolke, professor of psychology at the University of Warwick Medical School, and lead author of the study in the Journal of Pediatrics.
“The new chart of normal fuss/cry amounts in babies across industrialized countries will help health professionals to reassure parents whether a baby is crying within the normal expected range in the first three months or shows excessive crying which may require further evaluation and extra support for the parents.”
Source: University of Warwick
The US Environmental Protection Agency recently enacted regulations to reduce methane emissions from oil and natural gas production. They will cost about a third less than agency estimates, say researchers, but may not be enough to get to 2025 targets.
For a new study, researchers evaluated the recently updated EPA 2012 New Source Performance Standards that lay out how the oil and gas industry should detect and mitigate methane leaks.
The findings show that enforcing standards will cost about 27 percent less than EPA estimates. However, the methane emissions reductions will likely fall short of the agency’s 2025 mitigation targets by 20 to 50 percent, in part due to challenges with the technology used to detect leaks.
“We found out that even if you implement all these regulations as specified, what you achieve in terms of emissions reductions might be less than what the EPA estimates it’s going to achieve in terms of targets,” says lead author Arvind Ravikumar, a postdoctoral researcher at Stanford University’s School of Earth, Energy & Environmental Sciences. “One of the reasons it happens is because of uncertainty in both technology used to detect leaks as well as our understanding of leakage.”Waste less
In the paper, published in Environmental Research Letters, researchers made recommendations for how to improve reduction of methane leaks. Despite the president’s recent executive order to review the EPA’s regulations, the findings may be helpful to state-level regulators and companies developing new technologies to detect leaks in oil and gas operations.Old oil and gas wells can emit methane for decades
Methane leaks from natural gas operations contribute to rapid global warming while costing millions of dollars in economic loss. Methane is the primary component of natural gas, which is the top source of electricity production in the United States—and even small leaks can have large impacts on the planet.
Methane emissions cause about 25 percent of human-caused global warming today. Methane leaks can also threaten human health and safety, such as the 2015 Aliso Canyon leak in Southern California and multiple recent explosions in New York City caused by leaks in aging natural gas pipes.
“It would be better for everyone if we don’t waste gas,” Ravikumar says. “About 1 to 2 percent of gas is completely leaked now and fixing it is a direct economic value to both the operators, because they can sell that gas, and to consumers, because ultimately, we pay for it and prices are very volatile.”Finicky equipment
Federal law requires operators to survey for leaks using optical gas imaging or infrared cameras. But the technology’s accuracy depends on variables like weather conditions and time of day, making the equipment “notoriously finicky in terms of its performance,” says Ravikumar. The EPA estimates a 60 percent reduction in leaks from these periodic surveys, but researchers found the technology to range between 15 and 75 percent effective in actually reducing methane emissions.
The group based their findings on calculations from a software tool they adapted to model costs and benefits of mitigating methane leaks based on publicly available surveys conducted in US natural gas facilities over the last four years.
“We are using this tool to develop a quantitative and statistically supportable approach to evaluating a policy,” says coauthor Adam Brandt, assistant professor of energy resources engineering. “Not only that, because it’s open source, anyone can see exactly how the calculations are done, run it themselves, and see the effectiveness of a policy.”
The EPA regulations the group analyzed impose uniform standards on how often operators must inspect their facilities for leakage, what technology they can use, and how soon a problem should be addressed. But given the variability in natural gas facilities, researchers recommend addressing methane leaks from a regional and holistic perspective, such as coordinating with other greenhouse gas mitigation policies, rather than imposing uniform standards based on national averages.The Arctic emits more methane than we thought
“These are only recommendations,” Ravikumar says. “The methane business itself is fairly new and there are still many unknowns when it comes to methane emissions—given what we know, these ideas seem like the best way forward.”
To address the issue of varied results from infrared cameras, regulators should instead adopt a more technology-agnostic approach, the researchers say. Since the group’s software modeling tool was initially released in 2016, several organizations have begun developing alternate ways of detecting methane leaks that may prove more effective.
“Companies are developing detection technologies using our models,” says Brandt, who is also a Center Fellow at Stanford’s Precourt Institute for Energy and an affiliate at the Stanford Woods Institute for the Environment. “You can start to play with different variables and examine the costs and benefits associated with them.”
The researchers also recommend addressing emissions regionally since each basin features unique properties. For example, a possible solution would be indirect mitigation, in which the EPA sets a methane reduction target and then lets operators decide the best approach for reaching it.
“This research is not only applicable to the federal EPA rules—we are also talking with the California Air Resources Board,” Ravikumar says. “There’s a lot of interest around finding the best way to reduce emissions.”
Source: Stanford University
A component of the skin mucus secreted by certain South Indian frogs can kill the H1 variety of influenza viruses, say researchers.
Frogs’ skins are known to secrete peptides that defend them against bacteria. The findings of a new study suggest that the peptides represent a resource for antiviral drug discovery, too.
Anti-flu peptides could come in handy when vaccines are unavailable—in the case of a new pandemic strain, or when circulating strains become resistant to current drugs, says senior author Joshy Jacob, associate professor of microbiology and immunology at Emory Vaccine Center and Emory University School of Medicine.
Scientists named one of the antiviral peptides they identified urumin, after a whip-like sword called “urumi” used in southern India centuries ago. Urumin was found in skin secretions from the Indian frog Hydrophylax bahuvistara, which were collected after mild electrical stimulation.
Peptides are short chains of amino acids, the building blocks of proteins. Some antibacterial peptides work by punching holes in cell membranes, and are thus toxic to mammalian cells. Some antiviral peptides from the frogs were toxic in this way, but urumin wasn’t. Instead, it appears to only disrupt the integrity of flu virus, as seen through electron microscopy.
“I was almost knocked off my chair,” Jacob says. “In the beginning, I thought that when you do drug discovery, you have to go through thousands of drug candidates, even a million, before you get 1 or 2 hits. And here we did 32 peptides, and we had 4 hits.”Will the flu kill you? It may depend on your birth year
It turns out that urumin binds the stalk of hemagglutinin, a less variable region of the flu virus that is also the target of proposed universal vaccines. This specificity could be valuable because current anti-influenza drugs target other parts of the virus, Jacob says.
Because flu viruses from humans cannot infect frogs, producing urumin probably confers on frogs an advantage in fighting some other pathogen, Jacob says.
Delivered intranasally, urumin protected unvaccinated mice against a lethal dose of some flu viruses. Urumin was specific for H1 strains of flu, such as the 2009 pandemic strain, and was not effective against other current strains such as H3N2.
Developing antimicrobial peptides into effective drugs has been a challenge in the past, partly because enzymes in the body can break them down. Jacob’s lab is now exploring ways to stabilize antiviral peptides such as urumin, as well as looking for frog-derived peptides that are active against other viruses like dengue and Zika.
The paper appears in the journal Immunity. The first author is graduate student David Holthausen, and the research grew out of a collaboration with M.R. Pillai and Sanil George of the Rajiv Gandhi Center for Biotechnology. Emory University and the Office of Research Infrastructure Programs funded the work.
Source: Emory University
We need to consider the possible consequences of our 24-7 reliance on digital technology, warns a new book.
Our dependence on our phones, tablets, and laptops has dramatically changed how we communicate and interact, and is slowly eroding some of our core principles, says Michael Bugeja, professor and director of the Greenlee School of Journalism and Communication at Iowa State University. Bugeja is not advocating against technology—in fact, he relies on it for his work and personal life.
“If you do not assert yourself over technology, it will assert itself over you…”
But in his forthcoming book, Interpersonal Divide in the Age of the Machine (Oxford University Press, 2017), Bugeja explores what might happen if we allow machines to dictate our life. Those machines range from smartphones to robotics to virtual reality. Bugeja theorizes that because of our reliance on machines, we will start to develop the universal principles of technology, such as urgency, a need for constant updates, and a loss of privacy.
“We are losing empathy, compassion, truth-telling, fairness, and responsibility and replacing them with all these machine values,” Bugeja says. “If we embed ourselves in technology, what happens to those universal principles that have stopped wars and elevated human consciousness and conscience above more primitive times in history?”Can science offer us immortality? Should it?
Bugeja warns of the dangers associated with adopting these values. The proliferation of fake news is just one example of how this shift is already influencing our culture. Technology provides a continuous connection to our social media feeds, which has become a popular source for news for many Americans. However, social media tends to cultivate news stories that reflect our individual beliefs and values—not a broad spectrum of viewpoints—and is an easy way for fake news stories to spread, Bugeja says.
“The business of journalism is already feeling the effect of living in a world of correlation without causation,” he says. “We understand what happened and how it happened, but we don’t understand why it happened.”
That’s why Bugeja wants colleges and universities to require students to take media and technology literacy courses. He says it is important that students know where to go to find credible news stories, and open their minds to information from a variety of sources, not just those that confirm what they already think or believe.We’re great at avoiding inconvenient info
“We need these courses so that people know where to go for facts and how to deal with technology. If you do not assert yourself over technology, it will assert itself over you and you will be doing what the machine asks you, rather than you telling the machine what to do,” Bugeja says.
There is no easy short-term fix for the future, Bugeja says, which is why we need to temper our use. He says the long-term solution is through education.
It is not just the philosophical and intellectual consequences that have Bugeja concerned, but also the impact of technology on business, behavior, and everyday activities. Business and industry increasingly rely on machines or robots to do the jobs of humans. Bugeja says this shift can improve efficiency, safety, and the company’s bottom line, but he questions what will happen to those individuals who lose their jobs to machines.
“We introduce new gadgets by saying they will make our lives better, which is true, but there are also dangers,” Bugeja says.
Source: Iowa State University
While President Donald Trump’s base of support remains behind him, Americans are less supportive of the President’s policy ideas and of Congressional Republicans, a new poll shows.
“Republican candidates do not seem to be able to run away from the Trump agenda,” says James Morone, director of the Taubman Center for American Politics and Policy at Brown University’s Watson Institute for International and Public Affairs.
“Our deep drill down into different American settings shows a fiercely divided nation.”
For most of 2016, GOP candidates were more popular than Trump in their districts, but now Trump is polling ahead of generic GOP candidates. “Now, with Trump as president, Congressional Republicans face considerable headwinds in very different kinds of political settings,” Morone says.
RABA Research, a bi-partisan polling firm, in collaboration with Brown University to conduct the April 5 to 10 poll. It measured attitudes among 2,812 voters in five distinct types of counties: working class suburbs in Rhode Island, wealthy suburbs in Colorado, rural areas in Iowa, diverse rural areas in North and South Carolina, and upper middle class exurbs in Pennsylvania.
The poll, which is available on the Taubman Center website, included questions on trade and China, funding for Planned Parenthood, opioid abuse, attitudes about alleged Trump ties to Russia, and allegations that President Obama wiretapped Trump Tower during the campaign. It also asked participants about repealing the Affordable Care Act, imposing a travel ban on select countries, and building a wall between the US and Mexico.
In three of the five geographical areas polled, Trump’s current approval ratings suggest that many voters who supported him in the election do not approve of his performance in office. For example, Trump won the four counties Taubman polled in Iowa with a range of 62.1 to 70 percent of the vote.
Today, however, only 47 percent of voters in those counties rate his job performance “good” or “excellent.” However, in all four of those Iowa counties, Trump is more popular than generic Congressional Republicans matched against generic Democrats.
The poll also shows some voters souring on GOP plans to get rid of Obamacare. In the working class suburbs of Kent County, Rhode Island, 49 percent of voters oppose repealing the Affordable Care Act, while only 36 percent support it. The upper middle class voters in Arapahoe County, Colorado, who voted for both Obama and Clinton, also oppose scrapping the ACA, while rural voters in the Midwest and the south continue to voice support for Republicans looking to repeal the ACA.Poll finds most and least popular parts of ACA
In general, however, support for Trump outruns support for his policies. While Clinton’s America opposes efforts to defund Planned Parenthood, so does much of Trump’s—outside the South.
Support for other Trump priorities—including the building of a border wall with Mexico and a temporary travel ban placed on visitors from certain Muslim-majority countries—remains strong across four of the five areas surveyed.
“Our deep drill down into different American settings shows a fiercely divided nation,” Morone says.Liberals and conservatives read different science books
Strong partisan differences appear both between districts and within them. For example, in the upper middle class exurb of Chester County, Pennsylvania, which voted for Romney in 2012 and Clinton in 2016, Trump’s approval rating exceeds his vote count. At the same time, an extraordinary 44 percent of voters in that county say they have personally backed the opposition to Trump by writing letters, going to meetings, or contributing money.
“So here’s a county,” concludes Morone, “where 49 percent of the population says Trump is doing an excellent or good job while 44 percent claim to be organizing against him!”
The poll shows no systematic evidence of collapsing support for Trump despite the controversies that have surrounded his administration. Across the very different political settings, his approval rating very roughly reflects his November vote totals.
Source: Brown University