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By Ann Gibbons Neandertals have long been seen as the James Deans of human evolution—they grew up fast, died young, and became legends. But now, a rare skeleton of a Neandertal child suggests that our closest cousins didn’t all lead such fast lives—and that our own long childhoods aren’t unique. The find may reveal how Neandertals, like humans, had enough energy to grow bigger brains. “We like the paper because it puts the idea of ‘Neanderthal exceptionalism’ to rest,” wrote anthropologist Marcia Ponce de León and neurobiologist Christoph Zollikofer from the University of Zurich in Switzerland (who are not authors of the new study) in an email. “RIP.” Researchers have long known that modern humans take almost twice as long as chimpanzees to reach adulthood and have wondered when and why our ancestors evolved the ability to prolong childhood and delay reproduction. Our distant ancestors, such as the famous fossil Lucy and other australopithecines, matured quickly and died young like chimps. Even early members of our own genus Homo, such as the 1.6-million-year-old skeleton of an H. erectus boy, grew up faster than we do. By providing your email address, you agree to send your email address to the publication. Information provided here is subject to Science's Privacy Policy. But by the time the earliest known members of our species, H. sapiens, were alive 300,000 years ago at Jebel Irhoud in Morocco, they were taking longer to grow up. A leading theory is that big brains are so metabolically expensive that humans have to delay the age of reproduction—and, hence, have longer childhoods—so first-time mothers are older and, thus, bigger and strong enough to have the energy to feed babies with such big brains after birth when their brains are doubling in size. © 2017 American Association for the Advancement of Science

Keyword: Evolution; Development of the Brain
Link ID: 24098 - Posted: 09.22.2017

By STEPH YIN Worms and fish do it. Birds and bees do it. But do jellyfish fall asleep? It seems like a simple question, but answering it required a multistep investigation by a trio of Caltech graduate students. Their answer, published Thursday in Current Biology, is that at least one group of jellyfish called Cassiopea, or the upside-down jellyfish, does snooze. The finding is the first documented example of sleep in an animal with a diffuse nerve net, a system of neurons that are spread throughout an organism and not organized around a brain. It challenges the common notion that sleep requires a brain. It also suggests sleep could be an ancient behavior because the group that includes jellyfish branched off from the last common ancestor of most living animals early on in evolution. Working together was natural for Claire Bedbrook, Michael Abrams and Ravi Nath. The three leading co-authors of the paper are all Ph.D. candidates in biology at the California Institute of Technology and close friends. The project started with an observation by Mr. Abrams that some upside-down jellyfish in his lab would immediately slow their pulsing when the lights were turned off. Over coffee one evening, he discussed this phenomenon with Mr. Nath, who had been studying sleep in roundworms and pondering whether other “simple” animals slept. The two decided to visit Mr. Abrams’s lab in the middle of the night, to see how the jellyfish were behaving. The Cassiopea, or upside-down, jellyfish, demonstrated patterns of behavior consistent with sleep, according to an experiment conducted by Caltech graduate students. Credit Jan Easter Photography In the darkened lab, they observed a tankful of jellyfish pulsing infrequently and staying still for long periods of time — jellyfish that looked, in other words, like they were sleeping. Ms. Bedbrook started to believe they were onto something. © 2017 The New York Times Company

Keyword: Sleep; Evolution
Link ID: 24097 - Posted: 09.22.2017

Carrie Arnold The purpose and evolutionary origins of sleep are among the biggest mysteries in neuroscience. Every complex animal, from the humblest fruit fly to the largest blue whale, sleeps — yet scientists can’t explain why any organism would leave itself vulnerable to predators, and unable to eat or mate, for a large portion of the day. Now, researchers have demonstrated for the first time that even an organism without a brain — a kind of jellyfish — shows sleep-like behaviour, suggesting that the origins of sleep are more primitive than thought. Researchers observed that the rate at which Cassiopea jellyfish pulsed their bell decreased by one-third at night, and the animals were much slower to respond to external stimuli such as food or movement during that time. When deprived of their night-time rest, the jellies were less active the next day. “Everyone we talk to has an opinion about whether or not jellyfish sleep. It really forces them to grapple with the question of what sleep is,” says Ravi Nath, the paper’s first author and a molecular geneticist at the California Institute of Technology (Caltech) in Pasadena. The study was published on 21 September in Current Biology1. “This work provides compelling evidence for how early in evolution a sleep-like state evolved,” says Dion Dickman, a neuroscientist at the University of Southern California in Los Angeles. Nath is studying sleep in the worm Caenorhabditis elegans, but whenever he presented his work at research conferences, other scientists scoffed at the idea that such a simple animal could sleep. The question got Nath thinking: how minimal can an animal’s nervous system get before the creature lacks the ability to sleep? Nath’s obsession soon infected his friends and fellow Caltech PhD students Michael Abrams and Claire Bedbrook. Abrams works on jellyfish, and he suggested that one of these creatures would be a suitable model organism, because jellies have neurons but no central nervous system. Instead, their neurons connect in a decentralized neural net. © 2017 Macmillan Publishers Limited

Keyword: Sleep; Evolution
Link ID: 24096 - Posted: 09.22.2017

James Gorman Imagine a species that lived in a world of smells and didn’t pay a lot of attention to what things look like. What would members of that species use for a mirror? Would they even want a mirror? Yes, of course, we are talking about dogs, who usually don’t seem to understand the mirrors humans use. Sometimes they ignore them. Often they bark as if the dog in the mirror were a stranger. Scientists use mirrors to find out if animals recognize themselves, to see if they have some sense of self. Chimpanzees do very well on what is called the mirror test. A chimp will notice a mark on his face and perhaps even use the mirror to aid in removing it. He might use the mirror to examine parts of his body he can’t normally see, like the inside of his mouth. Researchers have reported that dolphins, one elephant and a magpie have also passed this test. Dogs have not, and that has raised questions about whether dogs might recognize themselves if another sense were tested. Alexandra Horowitz, a psychologist at Barnard College who studies the behavior of dogs and has written several books about them, decided to give dogs a chance at showing self-recognition on their own, smelly terms. In a recent study, she concludes that they do recognize the smell of their own urine. While some researchers find the study intriguing, the scientist who first developed that mirror mark test doesn’t think the evidence supports her conclusion. Still, even the idea of a smell mirror is mind (nose?) boggling. “I had always flirted with the idea in my head that there should be an olfactory mirror,” Dr. Horowitz said, acknowledging that “it could be horrifying for humans.” © 2017 The New York Times Company

Keyword: Chemical Senses (Smell & Taste); Consciousness
Link ID: 24095 - Posted: 09.22.2017

Katherine Ellen Foley, Youyou Zhou, Christopher Groskopf One way to understand long-term trends in medical and health research is to analyze the language used in massive bodies of literature produced in the different fields. To better understand the shifting focus of sex research since the field was established, we downloaded (with permission) 4,545 articles published in the Journal of Sex Research and the Archives of Sexual Behavior from 1970 to 2017, and tracked just over 1,000 of the most-used words in these studies. You can use the tool below to explore all of these words, and see how their frequency in the literature has changed over time. Beneath it, we’ve pulled out some of the most interesting trends we noticed and investigated possible explanations for why they’ve occurred. Humans have been having sex since as long as we’ve been on the planet, but it wasn’t until recently that we really started studying it. Sexology became a serious field just after World War II, starting with the work of Alfred Kinsey, a biologist at Indiana University, and later founder of the school’s Kinsey Institute, which today studies love and sexuality. Kinsey published his first book, Sexual Behavior in the Human Male, in 1948, followed by Sexual Behavior in the Human Female in 1953. In the 1960s, the field was further advanced by the work of lab mates (and lovers) William Masters and Victoria Johnson, who published the seminal Human Sexual Response in 1966.

Keyword: Sexual Behavior
Link ID: 24094 - Posted: 09.22.2017

By Gary Stix Donald Hebb was a famed Canadian scientist who produced key findings that ranged across the field of psychology, providing insights into perception, intelligence and emotion. He is perhaps best known, though, for his theory of learning and memory, which appears as an entry in most basic texts on neuroscience. But now an alternative theory—along with accompanying experimental evidence—fundamentally challenges some central tenets of Hebb’s thinking. It provides a detailed account of how cells and the electrical and molecular signals that activate them are involved in forming memories of a series of related events. Put forward in 1949, Hebb’s theory holds that when electrical activity in one neuron—perhaps triggered by observing one’s surroundings—repeatedly induces a neighboring “target cell” to fire electrical impulses, a process of conditioning occurs and strengthens the connection between the two neurons. This is a bit like doing arm curls with a weight; after repeated lifts the arm muscle grows stronger and the barbell gets easier to hoist. At the cellular level, repeated stimulation of one neuron by another enables the target cell to respond more readily the next time it is activated. In basic textbooks, this boils down to a simple adage to describe the physiology of learning and memory: “Cells that fire together, wire together.” Every theory requires experimental evidence, and scientists have toiled for years to validate Hebb’s idea in the laboratory. Many research findings have showed that when a neuron repeatedly fires off an electrical impulse (called an “action potential”) at virtually the same time as an adjacent neuron, their connection does indeed grow more efficient. The target cell fires more easily, and the signal transmitted is stronger. This process—known as long-term potentiation (LTP)—apparently induces physiological change or “plasticity” in target cells. LTP is routinely cited as a possible explanation for how the brain learns and forms memories at the cellular level. © 2017 Scientific American,

Keyword: Learning & Memory
Link ID: 24093 - Posted: 09.21.2017

By Ariana Eunjung Cha Over the past two decades, U.S. parents and teachers have reported epidemic levels of children with trouble focusing, impulsive behavior and so much energy that they are bouncing off walls. Educators, policymakers and scientists have referred to attention-deficit/hyperactivity disorder, or ADHD, as a national crisis and have spent billions of dollars looking into its cause. They've looked at genetics, brain development, exposure to lead, the push for early academics, and many other factors. But what if the answer to at least some cases of ADHD is more obvious? What if, as a growing number of researchers are proposing, many kids today simply aren't getting the sleep they need, leading to challenging behaviors that mimic ADHD? That provocative and controversial theory has been gaining momentum in recent years, with several studies suggesting strong links between ADHD and the length, timing and quality of sleep. In an era in which even toddlers know the words Netflix and Hulu, when demands for perfectionism extend to squirmy preschoolers and many elementary-age students juggle multiple extracurricular activities each day, one question is whether some kids are so stimulated or stressed that they are unable to sleep as much or as well as they should. Growing evidence suggests that a segment of children with ADHD are misdiagnosed and actually suffer from insufficient sleep, insomnia, obstructed breathing or another known sleep disorder. But the most paradigm-challenging idea may be that ADHD may itself be a sleep disorder. If correct, this idea could fundamentally change the way ADHD is studied and treated. © 1996-2017 The Washington Post

Keyword: ADHD; Sleep
Link ID: 24092 - Posted: 09.21.2017

By Alla Katsnelson, Men and women both transmit an increasing number of new mutations to their children as they age, according to a study published today in Nature1. The finding is based on an analysis of whole genomes from nearly 5,000 people. The increase in these ‘de novo’ mutations may explain why older parents are more likely to have a child with a condition such as autism. Men accumulate de novo mutations four times faster than women, the researchers found. However, in about 10 percent of the genome, mutations accumulate twice as quickly as elsewhere, and appear at an equal rate in both women and men. “The majority of the contribution still comes from the father, particularly when the father is in an older age range,” says lead investigator Kári Stefánsson, chief executive of deCODE Genetics. “But the mutation rate is not equal across the genome, so we have to make sure we do not generalize too much.” The new study builds on earlier work by deCODE Genetics, a company based in Reykjavik, Iceland. In 2012, the researchers reported that the rate at which people acquire mutations and pass them down to their children increases sharply with age in men but stays level in women. Those findings were based on whole-genome sequences from just 78 individuals and their parents. The findings provide one possible explanation for the increased risk of autism among children born to older parents. © 2017 Scientific American

Keyword: Sexual Behavior; Genes & Behavior
Link ID: 24091 - Posted: 09.21.2017

While immune cells called neutrophils are known to act as infantry in the body’s war on germs, a National Institutes of Health-funded study suggests they can act as medics as well. By studying rodents, researchers showed that instead of attacking germs, some neutrophils may help heal the brain after an intracerebral hemorrhage, a form of stroke caused by ruptured blood vessels. The study suggests that two neutrophil-related proteins may play critical roles in protecting the brain from stroke-induced damage and could be used as treatments for intracerebral hemorrhage. “Intracerebral hemorrhage is a damaging and often fatal form of stroke for which there are no effective medicines,” said Jaroslaw Aronowski, M.D., Ph.D., professor, department of neurology, at the University of Texas Health Science Center at Houston, and senior author of the study published in Nature Communications. “Our results are a hopeful first step towards developing a treatment for this devastating form of stroke.” Accounting for 10 to 15 percent of all strokes, intracerebral hemorrhages happen when blood vessels rupture and leak blood into the brain, often leading to death or long-term disability. Chronic high blood pressure is the leading risk factor for these types of strokes. The initial phase of damage appears to be caused by the pressure of blood leaking into the brain. Over time, further damage may be caused by the accumulation of toxic levels of blood products, infiltrating immune cells, and swelling. Decades of research suggest that neutrophils are some of the earliest immune cells to respond to a hemorrhage, and that they may both harm and heal the brain.

Keyword: Stroke; Neuroimmunology
Link ID: 24090 - Posted: 09.21.2017

Amber Dance Ninad Kothari’s workplace looks like something out of a sci-fi film. The graduate student at Johns Hopkins University works in a darkened, red-lit room, where he trains bats to fly through obstacle courses. Shielding within the walls keeps radio and other human-made signals from interfering with transmissions from the tiny electrical signals he’s recording from the bats’ brains as the animals bob and weave. Layers of foam further insulate the cavelike lab against sound waves. An array of cameras and microphones complete the futuristic scene. The high-tech setup has its homemade touches, too: In one obstacle course, bats dodge dangling Quaker oatmeal cylinders. Kothari is part of a small cadre of neuroscientists who are getting the best sense yet of how bat brains work at a cellular level, thanks to modern technologies. Eavesdropping tools, which rely on tiny probes that track the activities of individual nerve cells, or neurons, are now miniaturized enough to outfit bats with head-mounted, wireless sensors. As the animals fly freely around the lab, the researchers can listen in on neurons. By allowing the bats to behave naturally, unencumbered by bulky equipment, scientists will discover exciting new facets of how bat brains work, says neuroscientist Nachum Ulanovsky of the Weizmann Institute of Science in Rehovot, Israel, who invented the new wireless sensors with colleagues. He and others, studying several different species of bats, are investigating how the flying mammals perceive their environment and navigate through it. |© Society for Science & the Public 2000 - 2017

Keyword: Hearing
Link ID: 24089 - Posted: 09.21.2017

Patrick Barkham Humans trying to chat each other up in a noisy nightclub may find verbal communication futile. But it appears even more pointless for pumpkin toadlets after scientists discovered that females have lost the ability to hear the sound of male mating calls. An international team from Brazil, Denmark and the UK has discovered that the males of two species of tiny orange frogs continue to make high-pitched calls despite neither females nor males being able to hear them. It is believed to be the first case in the animal kingdom of a communication signal enduring even after its target audience has lost the ability to detect it. Field studies began in Brazil’s Atlantic forest by playing frog calls to determine how these species, which possess a middle ear, could hear their own calls. Lead researcher Dr Sandra Goutte at the Universidade Estadual de Campinas, São Paulo, was surprised to find the frogs refused to respond to her playback communication, didn’t change their calling behaviour and didn’t even orient themselves towards the sounds. “I thought I would find the sound transmission pathway from the outside to the middle ear,” she said. “We didn’t think it would be possible that they would not be able to hear their own calls.” © 2017 Guardian News and Media Limited

Keyword: Hearing; Sexual Behavior
Link ID: 24088 - Posted: 09.21.2017

by Emilie Reas Paranoia. Munchies. Giggles. Sleepiness. Memory loss. Although the effects of cannabinoids–the active components of marijuana–are familiar to many, their neurobiological substrates are poorly characterized. Perhaps the effect of greatest interest to both neuroscientists and to cannabis users hoping to preserve their cognitive function, is short-term memory impairment that often accompanies marijuana use. Our partial understanding of its physiological and behavioral effects is not for want of studies into its neural effects. Ample research has shown a range of changes to neurotransmission, receptors, ion channels and mitochondria following cannabinoid exposure. However, knowledge of its cellular and molecular properties alone cannot offer a complete picture of its system-wide effects leading to cognitive and behavioral changes. A recent study published in PLOS Computational Biology took a novel approach to address this issue, combining computational modeling with electrophysiological brain recordings from rats performing a memory task, to unravel the dynamics of neural circuits under the influence of cannabinoids. To assess memory changes induced by cannabinoids, the scientists injected tetrahydrocannabinol (THC), the main psychoactive compound in marijuana, into rats before they performed a “delayed-nonmatch-to-sample” working memory task. In this task, rats are cued with one of two levers, and after a delay, are required to select the opposite lever. Compared to sober sessions, performance under THC was impaired by 12%, confirming the all-too-familiar memory impairment associated with cannabis use. THC alters hippocampal activity

Keyword: Learning & Memory; Drug Abuse
Link ID: 24087 - Posted: 09.21.2017

Amy Maxmen Male ducks respond to sexual competition by growing either an extra-long penis or a nub of flesh, a new study finds. The unusual phenomena occurred in two species studied: the lesser scaup (Aythya affinis) and the ruddy duck (Oxyura jamaicensis). It suggests that penis size — in line with many traits and behaviours meant to impress or allow impregnation of the opposite sex — involves a trade-off between the potential to reproduce and to survive. Patricia Brennan, an evolutionary biologist at Mount Holyoke College in South Hadley, Massachusetts, compared the penises of ducks kept in male–female pairs to those housed with multiple males per female. The findings are published in a study on 20 September in The Auk: Ornithological Advances1. “If they were alone with a female, the males just grew a normal-sized penis, but if there were other males around, they had the ability to change dramatically,” Brennan says. “So evolution must be acting on the ability to be plastic — the ability to invest only in what is needed in your current circumstance.” Because evolutionary success relies on reproduction, genitals are adapted to meet the varied circumstances that every animal faces. Some male ducks, for example, have penises in the shape of corkscrews to navigate the labyrinth-like vaginas of their female counterparts. An earlier study by Brennan found that females’ anatomy evolved to prevent access to undesirable males who force copulation2. To mate successfully with their chosen partners, Brennan says, female ducks assume a posture that allows males to enter them fully and deposit sperm near eggs. © 2017 Macmillan Publishers Limited,

Keyword: Sexual Behavior; Evolution
Link ID: 24086 - Posted: 09.21.2017

Cordelia Fine argues no; Joe Herbert says yes. Cordelia Fine: A common assumption, which I refer to as the ‘Testosterone Rex’ view, is that testosterone is a proximal tool of distal evolutionary processes, acting via the brain (prenatally, then from pubescence) to shape sex differences in behaviour that would have been differentially reproductively advantageous for men versus women in our ancestral past. Joe, as you put it in your book Testosterone: Sex, power and the will to win, ‘for [male] reproduction to be successful, testosterone has to act on many parts of the male to make him fit for the competitive world of male sexuality’. So, for example, males’ greater testosterone exposure predisposes them to be more risk-taking and competitive than females – an idea sometimes called on to help explain gender gaps in risky and competitive occupations, a category which happens to include most high-status and well-remunerated roles. So what exactly does testosterone do? Testosterone acts directly on the brain, but the circulating level of testosterone in the blood is just one part of a highly complex, multi-faceted system. What’s more, different species appear to tweak those system dials in different ways, enabling cross-species differences in relations between hormones and behaviour. What do we need to try to explain when it comes to humans? One important feature of sex differences in behaviour is that these are much smaller than sex differences in testosterone exposure (a lot of overlap between female and male populations, and very little, respectively). This casts serious doubt on the assumption that more testosterone means more masculinity, and that men must inevitably be more masculine because they have higher absolute levels of testosterone on average. © Copyright 2000-2017 The British Psychological Society

Keyword: Sexual Behavior
Link ID: 24085 - Posted: 09.20.2017

Sigal Samuel James Kugel has been spent his entire scholarly career studying the Bible, but some very basic questions about it still obsess him. What was it about the minds of ancient Israelites that allowed them to hear and see God directly—or at least, to believe that they did? Were the biblical prophets literally hearing voices and seeing visions, understanding themselves to be transmitting God’s own exact words? If so, why did such direct encounters with God become rarer over time? In his new and final book, The Great Shift, Kugel investigates these questions through the lens of neuroscientific findings. (The approach is reminiscent of other recent books, like Kabbalah: A Neurocognitive Approach to Mystical Experiences, co-written by a neurologist and a mysticism scholar.) First, Kugel uses biblical research to show that ancient people had a “sense of self” that was fundamentally different from the one modern Westerners have—and that this enabled them to experience and interpret prophecy differently than we do. Then he uses scientific research to show that we shouldn’t assume their view was wrong. If anything, our modern Western notion of the bounded, individual self is the anomaly; most human beings throughout history conceived of the self as a porous entity open to intrusions. In fact, much of the rest of the world today still does. Kugel cites several studies showing that even now, many healthy people hear voices—as much as 15 percent of the general population. He also cites a recent cross-cultural study in which researchers interviewed voice hearers in the United States, Ghana, and India. The researchers recorded “striking differences” in how the different groups of people felt about the voices they hear: In Ghana and India, many participants “insisted that their predominant or even only experience of the voice was positive. … Not one American did so.” (c) 2017 by The Atlantic Monthly Group.

Keyword: Consciousness; Attention
Link ID: 24084 - Posted: 09.20.2017

By Bernardo Kastrup An article on the neuroscience of infant consciousness, which attracted some interest a few years ago, asked: “When does your baby become conscious?” The premise, of course, was that babies aren’t born conscious but, instead, develop consciousness at some point. (According to the article, it is about five months of age). Yet, it is hard to think that there is nothing it feels like to be a newborn. Newborns clearly seem to experience their own bodies, environment, the presence of their parents, etcetera—albeit in an unreflective, present-oriented manner. And if it always feels like something to be a baby, then babies don’t become conscious. Instead, they are conscious from the get-go. The problem is that, somewhat alarmingly, the word “consciousness” is often used in the literature as if it entailed or implied more than just the qualities of experience. Dijksterhuis and Nordgren, for instance, insisted that “it is very important to realize that attention is the key to distinguish between unconscious thought and conscious thought. Conscious thought is thought with attention.” This implies that if a thought escapes attention, then it is unconscious. But is the mere lack of attention enough to assert that a mental process lacks the qualities of experience? Couldn’t a process that escapes the focus of attention still feel like something? Consider your breathing right now: the sensation of air flowing through your nostrils, the movements of your diaphragm, etcetera. Were you not experiencing these sensations a moment ago, before I directed your attention to them? Or were you just unaware that you were experiencing them all along? By directing your attention to these sensations, did I make them conscious or did I simply cause you to experience the extra quality of knowing that the sensations were conscious? © 2017 Scientific American,

Keyword: Consciousness; Attention
Link ID: 24083 - Posted: 09.20.2017

By Deborah Tuerkheimer Controversy surrounding “shaken baby syndrome” (SBS) is taking centre stage again. The American Academy of Pediatrics (AAP) meets today with a session underscoring the message that most paediatricians – child abuse specialists among them – say it remains a “valid” diagnosis. In other words, the paediatric community continues to believe that shaking can bring about one or more of the classic triad of neurological symptoms: bleeding beneath the outer layer of membranes surrounding the brain, bleeding in the retina, and brain swelling. This is likely to prompt vigorous opposition from those within the medical community who challenge the scientific underpinnings of SBS. It is also likely to resonate with the public, many of whom assume that this diagnosis alone amounts to proof beyond a reasonable doubt that a caregiver or parent injured or killed a baby by violent shaking. It does not. Yet for decades such prosecutions did rest on the testimony of medical experts regarding the triad. Doctors came to court and explained that vigorous shaking – not an accidental jostle or an effort to revive an unconscious child – was the only possible explanation for those symptoms. The triad was even used to identify a perpetrator – whoever was last with the lucid baby. SBS could, in essence, be a medical diagnosis of murder. Beginning in the 1990s, triad-only prosecutions became increasingly commonplace, sending many caregivers to prison. © Copyright New Scientist Ltd.=

Keyword: Brain Injury/Concussion; Development of the Brain
Link ID: 24082 - Posted: 09.20.2017

Daniel Cressey Many sharks are living much longer than was thought, according to a major review1 of studies on these important and often endangered top predators. This means that many estimates of how threatened particular species are — and decisions about whether they can be fished safely — could be based on faulty data. Scientists usually estimate how old sharks are by slicing through their spines and counting distinctive pairs of bands seen inside, which are often assumed to show age in the same way as the rings of a tree. But a growing number of cases are suggesting that the method can be problematic. For example, a 2014 study2 showed that sand tiger sharks (Carcharias taurus), which were thought to live for around two decades, can actually survive for up to twice that. And in 2007, researchers found3 that New Zealand porbeagle sharks (Lamna nasus) had been under-aged by an average of 22 years. To investigate the scale of the problem, fisheries researcher Alastair Harry of James Cook University in Townsville, Australia, reviewed evidence for age underestimation. He reports in Fish and Fisheries1 that of 53 populations of sharks and rays for which there are good data, 30% have probably had their ages underestimated (see graphic). “Current evidence points to it being systemic, rather than restricted to a few isolated cases,” says Harry. “We really can’t ignore it anymore.” © 2017 Macmillan Publishers Limited,

Keyword: Development of the Brain
Link ID: 24081 - Posted: 09.20.2017

By Aylin Woodward HUMANS aren’t the only primate to have pushed their prey towards extinction. Monkeys have also over-exploited animals for food. Long-tailed macaques forage for shellfish on islands off Thailand, then crack them open with stone tools. They target the largest rock oysters, bludgeoning them with stone hammers, and pry open the meatiest snail and crab shells with the flattened edges of their tools. These macaques are one of three primates that use stone tools, alongside chimpanzees in Africa and bearded capuchins in South America. “Stone tools open up an opportunity for foods they otherwise wouldn’t even be able to harvest,” says Lydia Luncz at the University of Oxford. Luncz wanted to investigate the impact of the monkeys’ shellfish snacking on the prey themselves. Her team followed 18 macaques on their daily foraging routes along the shores of Koram and NomSao, two neighbouring islands off eastern Thailand, recording their tool selection and use. On Koram – the more densely populated island, home to 80 macaques compared with NomSao’s nine – Luncz’s group saw not only smaller oysters and snails, but also fewer of each species. Multiple prey species were less abundant on Koram than NomSao, with four times as many tropical periwinkles on NomSao as on Koram (eLife, doi.org/cc7d). © Copyright New Scientist Ltd.

Keyword: Evolution
Link ID: 24080 - Posted: 09.20.2017

“Bad fat” could be made to turn over a new leaf and combat obesity by blocking a specific protein, scientists have discovered. Most fat in the body is unhealthy “white” tissue deposited around the waist, hips and thighs. But smaller amounts of energy-hungry “brown” fat are also found around the neck and shoulders. Brown fat generates heat by burning up excess calories. Now scientists experimenting on lab mice have found a way to transform white fat into “beige” fat – a healthier halfway stage also capable of reducing weight gain. Dr Irfan Lodhi, from Washington University School of Medicine in the US, said: “Our goal is to find a way to treat or prevent obesity. “Our research suggests that by targeting a protein in white fat, we can convert bad fat into a type of fat that fights obesity.” Beige fat was discovered in adults in 2015 and shown to function in a similar way to brown fat. Lodhi’s team found that blocking a protein called PexRAP caused white fat in mice to be converted to beige fat that burned calories. The discovery, published in the journal Cell Reports, raises the prospect of more effective treatments for obesity and diabetes. The next step will be to find a safe way of blocking PexRAP in white fat cells in humans. Lodhi said: “The challenge will be finding safe ways to do that without causing a person to overheat or develop a fever, but drug developers now have a good target.” © 2017 Guardian News and Media Limited

Keyword: Obesity
Link ID: 24079 - Posted: 09.20.2017