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Susan Gaidos By age 25, Patrick Schnur had cycled through a series of treatment programs, trying different medications to kick his heroin habit. But the drugs posed problems too: Vivitrol injections were painful and created intense heroin cravings as the drug wore off. Suboxone left him drowsy, depressed and unable to study or go running like he wanted to. Determined to resume the life he had before his addiction, Schnur decided to hunker down and get clean on his own. In December 2015, he had been sober for two years and had just finished his first semester of college, with a 4.0 grade point average. Yet, just before the holidays, he gave in to the cravings. Settling into his dorm room he stuck a needle in his vein. It was his last shot. Scientists are searching for a different kind of shot to prevent such tragedies: a vaccine to counter addiction to heroin and other opioids, such as the prescription painkiller fentanyl and similar knockoff drugs. In some ways, the vaccines work like traditional vaccines for infectious diseases such as measles, priming the immune system to attack foreign molecules. But instead of targeting viruses, the vaccines zero in on addictive chemicals, training the immune system to usher the drugs out of the body before they can reach the brain. Such a vaccine may have helped Schnur, a onetime computer whiz who grew up in the Midwest, far removed from the hard edges of the drug world. His overdose death reflects a growing heroin epidemic and alarming trend. In the 1960s, heroin was seen as a hard-core street drug abused mostly in inner cities. Now heroin is a problem in many suburban and rural towns across America, where it is used primarily by young, white adults — male and female, according to research published by psychiatrist Theodore Cicero of Washington University in St. Louis and colleagues in 2014 in JAMA Psychiatry. © Society for Science & the Public 2000 - 201
Worldwide voting for the BEST ILLUSION OF THE YEAR will take place online from 4pm EST on June 29th to 4pm EST on June 30th. The winning illusions will receive a $3,000 award for 1st place, a $2,000 award for 2nd place, and a $1,000 award for 3rd place. Anybody with an internet connection (that means YOU!) can vote to pick the Top 3 Winners from the current Top 10 List! The Best illusion of the Year Contest is a celebration of the ingenuity and creativity of the world’s premier illusion research community. Contestants from all around the world submitted novel illusions (unpublished, or published no earlier than 2015), and an international panel of judges rated them and narrowed them to the TOP TEN.
Link ID: 22375 - Posted: 06.29.2016
Nicola Davis Death by cannibalism might seem like a high price to pay for a fleeting moment of passion, but male praying mantises are doing it for the kids, new research suggests. Scientists have discovered that female praying mantises who eat their mates after sex produce a greater number of eggs than those who do not, with the bodies of the ill-fated males used to aid their production. Of the species of praying mantises known to exhibit sexual cannibalism it is estimated up to 28% of males are eaten by their partner. After mating, the female stores the male’s sperm and later uses it to fertilise the eggs that she produces. The authors say the new study backs up a long-mooted theory that males could have evolved a behavioural trait of self-sacrifice to boost their reproductive success. “There is an obvious cost – you are dead, you have lost all future mating possibilities,” said William Brown, of the State University of New York at Fredonia, who co-authored the research. “We measure costs and benefit in terms of offspring production,” he added. If, by dying, the male can boost the number of offspring produced by one female, the theory goes, it could outweigh the downsides of missing out on future conquests. Published in the journal Proceedings of the Royal Society B by researchers in the US and Australia, the new study reveals how scientists unpicked the influence of cannibalism on the production of offspring in the praying mantis Tenodera sinensis, by tracking what happened to male ejaculate and bodily tissues after mating. © 2016 Guardian News and Media Limited
By Christie Aschwanden What is gender? It might sound like the kind of question that college students debate in a liberal arts class.1 But for the International Olympic Committee, it’s a practical question that demands a hard and fast answer. As at previous Olympic Games, athletes competing in Rio de Janeiro will be segregated into women’s events and men’s events, and that means the IOC needs a way to sort women from men. New IOC guidelines issued in November allow athletes who have transitioned to another gender to compete without sex reassignment surgery. The rules allow athletes who’d previously identified as female to compete in the male category without restriction, because they would not gain an advantage from their previous gender. Those who transition from male to female, on the other hand, must meet several requirements. The athlete must declare a female identity, and this identity cannot change for at least four years. The athlete must also document that her total serum testosterone levels have remained below a certain limit for a minimum of 12 months before competing, and these levels must remain under the threshold as long as she’s competing. The Olympic committee’s decision is a “huge step forward for everybody in the [transgender] community,” Caitlyn Jenner told me last week. “You can still have your old parts, which I think is very forward thinking.” Jenner is a trans woman who won the gold medal in the decathlon at the 1976 Olympics when she was Bruce Jenner, and she’s keeping the anatomical details of her own transition private. The public “is obsessed with — do you have it, or don’t have it?” she said, but “a trans person’s body parts is nobody’s business.”
Keyword: Sexual Behavior
Link ID: 22373 - Posted: 06.29.2016
By Ben Panko Everyone needs a stretch every now and then, but most lab rats don’t get the chance. According to new research, they are simply too confined in standard-sized cages to move naturally, potentially affecting their health and the outcomes of some experiments. Knowing that lab rat cages are a far cry from the rodents’ natural habitats, a team of scientists set out to observe the movements of some slightly more free-range rats. Most lab rats in the United States, Canada, and the European Union are housed in cages at least 18–20 centimeters tall, by regulation. But mature rats can reach almost twice that height when standing—between 26 and 30 centimeters. In the new experiment, scientists observed rats in much larger, multilevel habitats with a height of 125 centimeters. Compared with their tightly caged counterparts, who were unable to stand upright, 3-month-old rats stood an average of 178 times per day and 13-month-old rats stood an average of 73 times per day. They were also much more active: Three-month-old rats were seen climbing 76 times per day on average, whereas rats of all ages burrowed for about 20–30 minutes per day. The tightly caged rats, who don't have the space for these behaviors, seemed to stretch to make up for it, extending their bodies lengthwise nine times more often than rats housed in the larger cages, the scientists report today in Royal Society Open Science. The scientists say their findings are just the beginning of research into how standard laboratory cages may interfere with rats' normal movements. To find out how this may affect experimental results in fields like medicine and psychology, they say many more studies need to be done. © 2016 American Association for the Advancement of Science
Keyword: Animal Rights
Link ID: 22372 - Posted: 06.29.2016
By BENEDICT CAREY New York University’s medical school has quietly shut down eight studies at its prominent psychiatric research center and parted ways with a top researcher after discovering a series of violations in a study of an experimental, mind-altering drug. A subsequent federal investigation found lax oversight of study participants, most of whom had serious mental issues. The Food and Drug Administration investigators also found that records had been falsified and researchers had failed to keep accurate case histories. In one of the shuttered studies, people with a diagnosis of post-traumatic stress caused by childhood abuse took a relatively untested drug intended to mimic the effects of marijuana, to see if it relieved symptoms. “I think their intent was good, and they were considerate to me,” said one of those subjects, Diane Ruffcorn, 40, of Seattle, who said she was sexually abused as a child. “But what concerned me, I was given this drug, and all these tests, and then it was goodbye, I was on my own. There was no follow-up.” It’s a critical time for two important but still controversial areas of psychiatry: the search for a blood test or other biological sign of post-traumatic stress disorder, which has so far come up empty, and the use of recreational drugs like ecstasy and marijuana to treat it. At least one trial of marijuana, and one using ecstasy, are in the works for traumatized veterans, and some psychiatrists and many patients see this work as having enormous promise to reshape and improve treatment for trauma. But obtaining approval to use the drugs in experiments is still politically sensitive. Doctors who have done studies with these drugs say that their uncertain effects on traumatic memory make close supervision during treatment essential. © 2016 The New York Times Company
by German Lopez and Javier Zarracina After years of struggling with treatments for his worsening cancer, Roy was miserable — anxious, depressed, hopeless. Traditional cancer treatments had left him debilitated, and it was unclear whether they would save his life. But then Roy secured a spot in a clinical trial to test an exotic drug. The drug was not meant to cure his cancer; it was meant to cure his terror. And it worked. A few hours after taking a little pill, Roy declared to researchers, "Cancer is not important, the important stuff is love." His concerns about his imminent death had suddenly vanished — and the effects lasted for at least months, according to researchers. It was not a traditional antidepressant, like Zoloft, or anti-anxiety medication, like Xanax, that led Roy to reevaluate his life. It was a drug that has been illegal for decades but is now at the center of a renaissance in research: psilocybin, from hallucinogenic magic mushrooms. Psychologists and psychiatrists have been studying hallucinogens for decades — as treatment for things like alcoholism and depression, and to stimulate creativity. But support for studies dried up in the 1970s, after the federal government listed many psychedelics as Schedule 1 drugs. But now researchers are giving the drugs another look. © 2016 Vox Media, Inc.
By Clare Wilson People who meditate are more aware of their unconscious brain activity – or so a new take on a classic “free will” experiment suggests. The results hint that the feeling of conscious control over our actions can vary – and provide more clues to understanding the complex nature of free will. The famous experiment that challenged our notions of free will was first done in 1983 by neuroscientist Benjamin Libet. It involved measuring electrical activity in someone’s brain while asking them to press a button, whenever they like, while they watch a special clock that allows them to note the time precisely. Typically people feel like they decide to press the button about 200 milliseconds before their finger moves – but the electrodes reveal activity in the part of their brain that controls movement occurs a further 350 milliseconds before they feel they make that decision. This suggests that in fact it is the unconscious brain that “decides” when to press the button. In the new study, a team at the University of Sussex in Brighton, UK, did a slimmed-down version of the experiment (omitting the brain electrodes), with 57 volunteers, 11 of whom regularly practised mindfulness mediation. The meditators had a longer gap in time between when they felt like they decided to move their finger and when it physically moved – 149 compared with 68 milliseconds for the other people. © Copyright Reed Business Information Ltd.
Link ID: 22369 - Posted: 06.28.2016
By Rachel Rabkin Peachman It began with a simple roller-skating accident three years ago. Taylor Aschenbrenner, then 8 years old, lost her balance amid a jumble of classmates, tumbled to the floor and felt someone else’s skate roll over her left foot. The searing pain hit her immediately. The diagnosis, however, would take much longer. An X-ray, M.R.I.s, a CT scan and blood tests over several months revealed no evidence of a break, sprain or other significant problem. Taylor’s primary symptom was pain — so severe that she could not put weight on the foot. “Our family doctor first told us to give it some time,” said Taylor’s mother, Jodi Aschenbrenner, of Hudson, Wis. But time didn’t heal the pain. After about a month, an orthopedist recommended physical therapy. That didn’t end the problem, either. “I couldn’t walk or play outside or do anything,” Taylor said. After she had spent a year and a half on crutches, her orthopedist suggested she see Dr. Stefan Friedrichsdorf, the medical director ofpain medicine, palliative care and integrative medicine at Children’s Hospitals and Clinics of Minnesota. He and his team promptly recognized Taylor’s condition as complex regional pain syndrome, a misfiring within the peripheral and central nervous systems that causes pain signals to go into overdrive and stay turned on even after an initial injury or trauma has healed. He came up with a treatment plan for Taylor that included cognitive behavioral therapy, physical therapy, mind-body techniques, stress-reduction strategies, topical pain-relief patches and a focus on returning to her normal life and sleep routine, among other things. © 2016 The New York Times Company
Playing simple card games, such as snap, can help stroke patients with their recovery, say Canadian researchers. The scientists found it improved patients' motor skills. Playing Jenga, bingo or a games consol like Wii worked equally well. They told the Lancet Neurology that the type of task used for motor rehabilitation might be less relevant, as long as it is intensive, repetitive and gets the hands and arms moving. The researchers designed their study to test whether virtual reality gaming, which is increasingly being employed as a rehab therapy for stroke patients, is any better than more traditional games for honing upper limb motor skills. The Canadian team recruited 141 patients who had recently suffered a stroke, and now had some impaired movement in one or both of their hands and arms. Approximately half of the patients, at random, were then allocated to the Wii rehab, while the rest were asked to do other recreational activities, such as playing cards. All of the patients continued to receive usual stroke rehabilitation care and support on top of the 10, one-hour sessions of gaming or card playing for a fortnight. Both groups showed significant improvement in their motor skills at the end of the two weeks and four weeks later. Importantly, both groups fared equally well, say the researchers. While it's not clear from this study how much of the improvement was from the regular stroke care the participants received, other research suggests adding in more therapy is beneficial. Investigator Dr Gustavo Saposnik, from St Michael's Hospital in Toronto, said: "We all like technology and have the tendency to think that new technology is better than old-fashioned strategies, but sometimes that's not the case. In this study, we found that simple recreational activities that can be implemented anywhere may be as effective as technology." © 2016 BBC.
Link ID: 22367 - Posted: 06.28.2016
Emily Conover Sharks have a sixth sense that helps them locate prey in murky ocean waters. They rely on special pores on their heads and snouts, called ampullae of Lorenzini, that can sense electric fields generated when nearby prey move. The pores were first described in 1678, but scientists haven’t been sure how they work. Now, the answer is a bit closer. The pores, which connect to electrosensing cells, are filled with a mysterious clear jelly. This jelly is a highly efficient proton conductor, researchers report May 13 in Science Advances. In the jelly, positively charged particles move and transmit current. Marco Rolandi of the University of California, Santa Cruz and colleagues squeezed jelly from the pores of one kind of shark and two kinds of skate and tested how well protons could flow through the substance. Good proton conductors, including a protein found in squid skin, occur in nature. But the jelly is the best biological proton conductor discovered so far. In fact, even humankind’s best technology isn’t wildly better. The most efficient proton conductor devised by people — a polymer known as Nafion — is a mere 40 times better than the stuff sharks are born with. Citations E.E. Josberger et al. Proton conductivity in ampullae of Lorenzini jelly. Science Advances. Published online May 13, 2016. doi:10.1126/sciadv.1600112. Further Reading |© Society for Science & the Public 2000 - 2016.
Keyword: Pain & Touch
Link ID: 22366 - Posted: 06.28.2016
By MAIA SZALAVITZ I SHOT heroin and cocaine while attending Columbia in the 1980s, sometimes injecting many times a day and leaving scars that are still visible. I kept using, even after I was suspended from school, after I overdosed and even after I was arrested for dealing, despite knowing that this could reduce my chances of staying out of prison. My parents were devastated: They couldn’t understand what had happened to their “gifted” child who had always excelled academically. They kept hoping I would just somehow stop, even though every time I tried to quit, I relapsed within months. There are, speaking broadly, two schools of thought on addiction: The first was that my brain had been chemically “hijacked” by drugs, leaving me no control over a chronic, progressive disease. The second was simply that I was a selfish criminal, with little regard for others, as much of the public still seems to believe. (When it’s our own loved ones who become addicted, we tend to favor the first explanation; when it’s someone else’s, we favor the second.) We are long overdue for a new perspective — both because our understanding of the neuroscience underlying addiction has changed and because so many existing treatments simply don’t work. Addiction is indeed a brain problem, but it’s not a degenerative pathology like Alzheimer’s disease or cancer, nor is it evidence of a criminal mind. Instead, it’s a learning disorder, a difference in the wiring of the brain that affects the way we process information about motivation, reward and punishment. And, as with many learning disorders, addictive behavior is shaped by genetic and environmental influences over the course of development. Scientists have documented the connection between learning processes and addiction for decades. Now, through both animal research and imaging studies, neuroscientists are starting to recognize which brain regions are involved in addiction and how. © 2016 The New York Times Company
Keyword: Drug Abuse
Link ID: 22365 - Posted: 06.27.2016
By Sara Chodosh Although scientists have learned a lot about the brain in the last few decades, approaches to treating mental illnesses have not kept up. As neuroscientists learn more about brain circuits, Stanford psychiatrist Amit Etkin foresees a time when diagnoses will be based on brain scans rather than symptoms. Etkin, who will be speaking at the World Economic Forum’s Annual Meeting of the New Champions in Tianjin, China, from June 26 to 28, spoke with Scientific American about his research on the neurological basis of emotional disorders and the future of mental health treatment. The high cost of treating mental illness doesn’t get talked about very much. Why is that? It’s a really interesting issue. The costs associated with mental illness are not just the care of people who have an illness, which often starts early in life and continues as a lifelong process, but also the cost to employers in decreased productivity and the cost to society in general. A report that came out recently in Health Affairs showed that spending within our health system in the U.S. is greater for mental illness than for any other area of medicine, and yet our understanding of these illnesses is incredibly backwards. Treatments are no different than they were 40 years ago, so that feels like a problem that is only getting bigger without an obvious solution. Why hasn’t there been much progress? It was really not until about 10 years ago that [mental health professionals] started realizing how little difference we have made. There are a few fundamental issues and mistakes we’ve made. One is that in the absence of knowing what the causes of the illnesses that we treat are, we focus on the symptoms, and that has already led us down the wrong path. If you go to another country and you ask somebody to tell you their symptoms, as a clinician you might have the sense that they have anxiety or depression. In Asian countries they express that in a somatic way: “I can’t sleep” or “I feel weak.” The biology cannot be that different, but the symptoms are different because they’re culturally bound. If you look at different parts of the U.S. you’ll see people expressing symptoms in different ways depending on their local culture. If that’s the case, then a symptom-based definition is problematic. The long and short of it is that people have named syndromes or disorders that they don’t actually know represent a valid entity that is distinct from another entity. © 2016 Scientific American
By VANESSA FRIEDMAN IT’S been another big month for talking about women’s bodies. Just as the White House hosted the first United States of Women summit meeting, which culminated in Oprah Winfrey’s noting, in conversation with Michelle Obama, “We live in a world where you are constantly being bombarded by images,” across the ocean the new mayor of London was announcing a policy that would ban ads on public transport that might cause women to feel pressured “into unrealistic expectations surrounding their bodies.” Mayor Sadiq Khan’s policy sounds, on the surface, like a big step forward. Down with fat-shaming! But it is, rather, an old idea, and one that reinforces stereotypes instead of grappling with the real issue: How do we change the paradigm altogether? The immediate impetus for the ban, which will be carried out by the London transit authority via a steering committee that will rule on ads case by case, was a 2015 diet pill ad depicting a very tan, very curvy woman (the kind who is a staple of lad mags) in a bright yellow bikini alongside the words, “Are you beach body ready?” The implication was that if you had not achieved the unrealistic proportions of a Barbie, you were not. The public protested (a petition on change.org received more than 70,000 signatures), and Mr. Khan made it part of his election campaign. The regulation follows decisions by the Advertising Standards Authority of Britain to ban certain ads, such as a Gucci shot that depicted what was deemed an “unhealthily thin” young woman. Though often conflated with the movement to protect models, which resulted in legislation in France in 2015 requiring models to produce a doctor’s note attesting to their health, and digital alteration of photographs to be disclosed, banning is a separate issue. It doesn’t involve working conditions (which can and should be legislated), but subjective, and ultimately regressive, assumptions about what constitutes a positive female image. While I have no doubt that Mr. Khan had the best intentions (he made a reference to his desire to protect his daughters), and there is no question that studies have shown that depictions of thin women in idealized or overly airbrushed photographs can be an important factor in eating disorders and other types of body dysmorphia, I do not believe banning is the answer. And I say that as someone with two daughters (and a son) who is acutely aware of the distortions of the fashion world and their dangers. © 2016 The New York Times Company
Keyword: Anorexia & Bulimia
Link ID: 22363 - Posted: 06.27.2016
By Perri Klass, M.D. In the 1990s, in my first month in practice as a pediatrician, I asked the mother of a 4-year-old about discipline and she told me that her son was often out of line and wild, and spanking was the only thing that worked, though she was sure I was going to tell her not to, just as her previous pediatrician had done. Around the same time, my colleague in the same clinic walked into an exam room to find a cranky toddler who was acting out, and a frustrated father who was taking off his belt and threatening punishment. In each case, and in many others, we had to decide how to talk to the parents, and whether to bring up the issue of child abuse — which is definitely an issue when a child is being struck, or threatened, with a belt. Corporal punishment, also known as “physical discipline,” has become illegal in recent decades in many countries, starting with Sweden in 1979. The United States is not one of those countries, and pediatricians regularly find ourselves talking with parents about why hitting children is a bad idea. The American Academy of Pediatrics officially recommends against physical discipline, saying that evidence shows it is ineffective and puts children at risk for abuse; pediatricians are mandated reporters, responsible for notifying the authorities if we think there is a possibility of abuse, though the boundaries are not clearly defined by law. But many parents continue to spank, even when they don’t think it does much good. In a recent report by the nonprofit organization Zero to Three of a national sample of 2,200 parents of children birth to age 5, parents were asked which discipline strategies they used a few times a week or more. Twenty-six percent said they “pop or swat” their child, 21 percent spank, and 17 percent reported hitting with an object like a belt or a wooden spoon. (Parents could respond that they used more than one strategy.) Zero to Three reported that even those who used these strategies frequently did not rate them as effective, and 30 percent agreed with the statement, “I spank even though I don’t feel O.K. about it.” © 2016 The New York Times Company
By Elizabeth Pennisi Cave fish have long fascinated biologists because of their missing eyes and pale skin. Now, one researcher is studying them for another reason: Their behavior may provide clues to the genetic basis of some human psychiatric disorders. Last week at the 23rd International Conference on Subterranean Biology in Fayetteville, Arkansas, he demonstrated how drugs that help people with schizophrenia and autism similarly affect the fish. “I think there is a lot of potential” for these fish to teach us about mental disorders, says David Culver, an evolutionary biologist at American University in Washington, D.C., who was not involved in the study. Culver adds that—like other work on the cause of cave fish blindness—the new research may also have implications for human disease. A decade ago, the lead author on the new study, Masato Yoshizawa, wanted to understand brain evolution by investigating the effects of natural selection on behavior. The Mexican tetra (Astyanax mexicanus), a cave fish with very close surface relatives, seemed an excellent prospect for that work. Because the two populations can interbreed, it’s easier to pin down genes that might be related to the neural defects underlying behavioral differences. Such breeding studies are not possible in humans. The blind cave fish differ from their surface relatives in several notable ways. They don’t have a social structure and they don’t school. Instead, they lead solitary lives—a behavior that makes sense given their lack of natural predators. They also almost never sleep. They are hyperactive, and—unlike other fish—they are attracted to certain vibrations in the water. Finally, they tend to do the same behavior over and over again and seem to have higher anxiety than their surface relatives. © 2016 American Association for the Advancement of Science.
By MOSHE BAR A FRIEND of mine has a bad habit of narrating his experiences as they are taking place. I tease him for being a bystander in his own life. To be fair, we all fail to experience life to the fullest. Typically, our minds are too occupied with thoughts to allow complete immersion even in what is right in front of us. Sometimes, this is O.K. I am happy not to remember passing a long stretch of my daily commute because my mind has wandered and my morning drive can be done on autopilot. But I do not want to disappear from too much of life. Too often we eat meals without tasting them, look at something beautiful without seeing it. An entire exchange with my daughter (please forgive me) can take place without my being there at all. Recently, I discovered how much we overlook, not just about the world, but also about the full potential of our inner life, when our mind is cluttered. In a study published in this month’s Psychological Science, the graduate student Shira Baror and I demonstrate that the capacity for original and creative thinking is markedly stymied by stray thoughts, obsessive ruminations and other forms of “mental load.” Many psychologists assume that the mind, left to its own devices, is inclined to follow a well-worn path of familiar associations. But our findings suggest that innovative thinking, not routine ideation, is our default cognitive mode when our minds are clear. In a series of experiments, we gave participants a free-association task while simultaneously taxing their mental capacity to different degrees. In one experiment, for example, we asked half the participants to keep in mind a string of seven digits, and the other half to remember just two digits. While the participants maintained these strings in working memory, they were given a word (e.g., shoe) and asked to respond as quickly as possible with the first word that came to mind (e.g., sock). © 2016 The New York Times Company
Link ID: 22360 - Posted: 06.25.2016
Annie Murphy Paul Twelve years ago, I tried to drive a stake into the heart of the personality-testing industry. Personality tests are neither valid nor reliable, I argued, and we should stop using them — especially for making decisions that affect the course of people's lives, like workplace hiring and promotion. But if I thought that my book, The Cult of Personality Testing, would lead to change in the world, I was keenly mistaken. Personality tests appear to be more popular than ever. I say "appear" because — today as when I wrote the book — verifiable numbers on the use of such tests are hard to come by. Personality testing is an industry the way astrology or dream analysis is an industry: slippery, often underground, hard to monitor or measure. There are the personality tests administered to job applicants "to determine if you're a good fit for the company;" there are the personality tests imposed on people who are already employed, "in order to facilitate teamwork;" there are the personality tests we take voluntarily, in career counseling offices and on self-improvement retreats and in the back pages of magazines (or, increasingly, online.) I know these tests are popular because after the book was published, most of the people I heard from were personality-test enthusiasts, eager to rebut my critique of the tests that had, they said, changed their lives. © 2016 npr
Link ID: 22359 - Posted: 06.25.2016
By Patrick Monahan The soft, blinking lights of fireflies aren’t just beautiful—they may also play a role in creating new species. A new study shows that using light-up powers for courtship makes species split off from each other at a faster pace, providing some of the clearest evidence yet that the struggle to find mates shapes the diversity of life. The firefly’s glow, like the enormous claws of fiddler crabs and the elaborate dances of manakins, was sculpted by the struggle for sex. Scientists have long thought that this kind of mating-driven natural selection—called “sexual selection”—could make species split into two. Say females in two populations prefer different color patterns in males: Even if the populations have the same needs in every other way, that simple preference could make them split into species with males of separate colors. “A lot of closely related species differ in sexual traits,” says Emily Ellis, an evolutionary biologist at the University of California (UC), Santa Barbara. But actually linking this kind of evolution to species proliferation is a hard idea to test. “So many people have looked at this and found differing results,” she says—possibly because they looked at smaller groups, like birds, rather than across the whole tree of life. That’s where bioluminescence comes in. Many groups of living organisms, from insects to fish to octopuses, emit light, whether to ward off predators, dazzle prey, or attract mates. It’s a trait that has evolved more than 40 times across the animal kingdom, Ellis says. © 2016 American Association for the Advancement of Science.
By Eric Hand That many animals sense and respond to Earth’s magnetic field is no longer in doubt, and people, too, may have a magnetic sense. But how this sixth sense might work remains a mystery. Some researchers say it relies on an iron mineral, magnetite; others invoke a protein in the retina called cryptochrome. Magnetite has turned up in bird beaks and fish noses and even in the human brain, as Joe Kirschvink of the California Institute for Technology in Pasadena reported in 1992, and it is extremely sensitive to magnetic fields. As a result, Kirschvink and other fans say, it can tell an animal not only which way it is heading (compass sense) but also where it is. “A compass cannot explain how a sea turtle can migrate all the way around the ocean and return to the same specific stretch of beach where it started out,” says neurobiologist Kenneth Lohmann of the University of North Carolina, Chapel Hill. A compass sense is enough for an animal to figure out latitude, based on changes in the inclination of magnetic field lines (flat at the equator, plunging into the earth at the poles). But longitude requires detecting subtle variations in field strength from place to place—an extra map or signpost sense that magnetite could supply, Lohmann says. Except in bacteria, however, no one has seen magnetite crystals serving as a magnetic sensor. The crystals could be something else—say, waste products of iron metabolism, or a way for the body to sequester carcinogenic heavy metals. In the early 2000s, scientists found magnetite-bearing cells in the beaks of pigeons. But a follow-up study found that the supposed magnetoreceptors were in fact scavenger immune cells that had nothing to do with the neural system. And because there is no unique stain or marker for magnetite, false sightings are easy to make. © 2016 American Association for the Advancement of Science
Keyword: Pain & Touch
Link ID: 22357 - Posted: 06.24.2016