Chapter 16. None
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By Smitha Mundasad Health reporter, BBC News Scientists have discovered a central hub of brain cells that may put the brakes on a desire to eat, a study in mice shows. And switching on these neurons can stop feeding immediately, according to the Nature Neurosciences report. Researchers say the findings may one day contribute to therapies for obesity and anorexia. Experts say this sheds light on the many complex nerve circuits involved in appetite control. Scientists from the California Institute of Technology suggest the nerve cells act as a central switchboard, combining and relaying many different messages in the brain to help reduce food intake. Using laser beams they were able to stimulate the neurons - leading to a complete and immediate stop to food consumption. Prof David Anderson, lead author of the study told the BBC: "It was incredibly surprising. "It was like you could just flick a switch and prevent the animals from feeding." Researchers then used chemicals to mimic a variety of scenarios - including feelings of satiety, malaise, nausea and a bitter taste. They found the neurons were active in all situations, suggesting they may be integral in the response to many diverse stimuli. BBC © 2014
Link ID: 19887 - Posted: 07.28.2014
|By James Phillips Our inner ear is a marvel. The labyrinthine vestibular system within it is a delicate, byzantine structure made up of tiny canals, crystals and pouches. When healthy, this system enables us to keep our balance and orient ourselves. Unfortunately, a study in the Archives of Internal Medicine found that 35 percent of adults over age 40 suffer from vestibular dysfunction. A number of treatments are available for vestibular problems. During an acute attack of vertigo, vestibular suppressants and antinausea medications can reduce the sensation of motion as well as nausea and vomiting. Sedatives can help patients sleep and rest. Anti-inflammatory drugs can reduce any damage from acute inflammation and antibiotics can treat an infection. If a structural change in the inner ear has loosened some of its particulate matter—for instance, if otolith (calcareous) crystals, which are normally in tilt-sensitive sacs, end up in the semicircular canals, making the canals tilt-sensitive—simple repositioning exercises in the clinic can shake the loose material, returning it where it belongs. After a successful round of therapy, patients no longer sense that they are tilting whenever they turn their heads. If vertigo is a recurrent problem, injecting certain medications can reduce or eliminate the fluctuating function in the affected ear. As a last resort, a surgeon can effectively destroy the inner ear—either by directly damaging the end organs or by cutting the eighth cranial nerve fibers, which carry vestibular information to the brain. The latter surgery involves removing a portion of the skull and shifting the brain sideways, so it is not for the faint of heart. © 2014 Scientific American
Link ID: 19886 - Posted: 07.28.2014
By Michael Brooks Occasionally, scientific research comes up with banal findings that should nonetheless stop us in our tracks. For example, researchers recently published a study showing that a father’s brain will change its hormonal outputs and neural activity depending on his parenting duties. The conclusion of the research is, in essence, that men make good parents, too. Surely this is not news. Yet it does provide evidence that is sadly still useful. Those involved with issues of adoption, fathers’ rights, gay rights, child custody, and religion-fuelled bigotry will all benefit from understanding what we now know about what makes a good parent. The biggest enemy of progress has been the natural world, or at least our view of it. Females are the primary caregivers in 95 percent of mammal species. That is mainly because of lactation. Infants are nourished by their mothers’ milk, so it makes sense for most early caring to be done by females. Human beings, however, have developed more sophisticated means of nourishing and raising our offspring. Should the circumstances require a different set-up, we have ways to cope. It turns out that this is not just in terms of formula milk, nannies or day care: We also have a flexible brain. The new study, published in Proceedings of the National Academy of Sciences, scanned the brains of parents while they watched videos of their interactions with their children. The researchers found that this stimulated activity in two systems of the brain. One is an emotional network that deals with social bonding, ensures vigilance and coordinates responses to distress, providing chemical rewards for behaviours that maintain the child’s well-being. The other network is concerned with mental processing. It monitors the child’s likely state of mind, emotional condition, and future needs, allowing for planning. 2014 © The New Republic.
Keyword: Sexual Behavior
Link ID: 19883 - Posted: 07.26.2014
By James Gallagher Health editor, BBC News website Even low levels of light in bedrooms may stop breast cancer drugs from working, US researchers have warned. Animal tests showed light, equivalent to that from street lamps, could lead to tumours becoming resistant to the widely used drug Tamoxifen. The study, published in the journal Cancer Research, showed the light affected sleep hormones, which in turn altered cancer cell function. UK experts said it was an intriguing finding, but not proven in people. Tamoxifen has transformed the treatment of breast cancer by extending lives and increasing survival times. It stops the female hormone oestrogen fuelling the growth of tumours although the cancerous cells may eventually become resistant to the drug. Light Researchers at the Tulane University School of Medicine investigated the role of the body clock in Tamoxifen resistance. They focused their research on the sleep-promoting hormone melatonin, which normally begins to rise in the evening and continues through the night, before falling away as dawn approaches. However, light in the evening - such as from a smartphone, tablet or artificial lights - can lower melatonin levels. Rats, with human breast cancer and treated with Tamoxifen, were left to sleep in a completely dark cage or one that had dim light. The scientists showed that in dim light, melatonin levels were lower, the tumours were bigger and were resistant to Tamoxifen. A second set of tests showed that giving those mice melatonin supplements kept Tamoxifen working and resulted in smaller tumours. BBC © 2014
Keyword: Biological Rhythms
Link ID: 19881 - Posted: 07.26.2014
by Claudia Caruana GOT that ringing in your ears? Tinnitus, the debilitating condition that plagued Beethoven and Darwin, affects roughly 10 per cent of the world's population, including 30 million people in the US alone. Now, a device based on vagus nerve stimulation promises to eliminate the sounds for good by retraining the brain. At the moment, many chronic sufferers turn to state of the art hearing aids configured to play specific tones meant to cancel out the tinnitus. But these do not always work because they just mask the noise. The new device, developed by MicroTransponder in Dallas, Texas, works in an entirely different way. The Serenity System uses a transmitter connected to the vagus nerve in the neck – the vagus nerve connects the brain to many of the body's organs. The thinking goes that most cases of chronic tinnitus result from changes in the signals sent from the ear to neurons in the brain's auditory cortex. This device is meant to retrain those neurons to forget the annoying noise. To use the system, a person wears headphones and listens to computer-generated sounds. First, they listen to tones that trigger the tinnitus before being played different frequencies close to the problematic one. Meanwhile, the implant stimulates the vagus nerve with small pulses. The pulses trigger the release of chemicals that increase the brain's ability to reconfigure itself. The process has already worked in rats (Nature, doi.org/b63kt9) and in a small human trial this year, where it helped around half of the participants. "Vagus nerve stimulation takes advantage of the brain's neuroplasticity – the ability to reconfigure itself," says Michael Kilgard at the University of Texas at Dallas, and a consultant to MicroTransponder. © Copyright Reed Business Information Ltd.
Posted by Katie Langin In a battle of wits, could a bird outsmart a kindergartner? Don’t be too quick to say no: One clever young bird solved a problem that has stumped 5-year-old children, according to a new study. The bird—a New Caledonian crow named Kitty—figured out that dropping rocks in one water-filled tube was the key to raising the water level in another, seemingly unconnected tube, giving her access to a floating morsel of meat. To solve this problem, Kitty needed to decipher a confusing cause-and-effect relationship, basically akin to figuring out that if you flip a switch on the wall, a ceiling light will turn on. This mental ability was once thought to be restricted to humans, but causal reasoning—the ability to understand cause and effect—has now been identified in a handful of animals, from chimpanzees to rats. Crows are the Einsteins of the bird world, renowned for their ability to make tools and solve complex puzzles. (Watch a video of a New Caledonian crow solving problems.) Their impressive mental capacity was even apparent to the ancient Greeks. In one of Aesop’s fables, a thirsty crow is presented with a dilemma when he cannot reach the water at the bottom of a pitcher. He figures out that the water level rises when he drops pebbles into the pitcher, and many pebbles later he is rewarded with a drink. As it turns out, there’s some truth to this fictional story. A study published earlier this year reported that New Caledonian crows will place rocks in water-filled tubes if they can’t reach a piece of meat that is attached to a floating cork. © 1996-2013 National Geographic Society.
By JAMES GORMAN Any dog owner would testify that dogs are just as prone to jealousy as humans. But can one really compare Othello’s agony to Roscoe’s pique? The answer, according to Christine Harris, a psychologist at the University of California, San Diego, is that if you are petting another dog, Roscoe is going to show something that Dr. Harris thinks is a form of jealousy, even if not as complex and twisted as the adult human form. Other scientists agree there is something going on, but not all are convinced it is jealousy. And Roscoe and the rest of his tribe were, without exception, unavailable for comment. Dr. Harris had been studying human jealousy for years when she took this question on, inspired partly by the antics of her parents’ Border collies. When she petted them, “one would take his head and knock the other’s head away,” she said. It certainly looked like jealousy. But having studied humans, she was aware of different schools of thought about jealousy. Some scientists argue that jealousy requires complex thinking about self and others, which seems beyond dogs’ abilities. Others think that although our descriptions of jealousy are complex, the emotion itself may not be that complex. Dog emotions, as owners perceive them, have been studied before. In one case, Alexandra Horowitz, a cognitive scientist who is an adjunct associate professor at Barnard College and the author of “Inside of a Dog,” found that the so-called guilty look that dogs exhibit seemed to be more related to fear of punishment. Dr. Harris ventured into the tricky turf of dog emotion by devising a test based on work done with infants. © 2014 The New York Times Company
By Phil Plait From the twisted mind of brusspup comes another brain-hurting illusion. This one is really, really convincing, so tell me: When you look at this video, you’re seeing a circle of eight dots rotating as it spins around inside a bigger circle, right? No, you’re not. As brusspup shows, each individual white dot is moving in a straight line! The trick here is two-fold: One is that the dots aren’t moving at constant velocity (you can see that in the video at the 0:44 mark), and that combined their motion mimics what we’d see if a smaller circle is rolling around inside a big one. Try as I may, when I look at this video I can’t make my brain see the dots moving linearly; it looks like a circle rolling. If I focus on one of the dots I can see it moving back and forth along a line, but the others still look like the rim of a circle rolling around. For most illusions there’s a moment when your brain can see what’s going on and the illusion shatters, but not with this one. It’s maddening. When I was a kid, Spirograph was a very popular “game.” It wasn’t really a game, but a set of clear plastic disks with gear teeth around them (or rings with teeth on the inside). They had holes in them; you’d pin a ring down on a piece of paper, then take another disk, place it inside the ring, put your pencil tip in a hole, and roll the inner disk around inside the outer ring. The results were really lovely and graceful interlocking and overlapping curves. If you’re a lot younger than me and missed this craze, here’s a video that’ll help you picture it: © 2014 The Slate Group LLC.
Link ID: 19874 - Posted: 07.24.2014
By Emily Underwood The Broad Institute, a collaborative biomedical research center in Cambridge, Massachusetts, has received a $650 million donation from philanthropist and businessman Ted Stanley to study the biological basis of diseases such as schizophrenia and bipolar disorder. The largest donation ever made to psychiatric research, the gift totals nearly six times the current $110 million annual budget for President Barack Obama’s Brain Research through Advancing Innovative Neurotechnologies (BRAIN) Initiative. Stanley has already given Broad $175 million, and the $650 million will be provided as an annual cash flow on the order of tens of millions each year, with the remainder to be given after Stanley’s death. The gift accompanies a paper published online today in Nature from researchers at Broad and worldwide, which identifies more than 100 areas of the human genome associated with schizophrenia, based on samples from almost 37,000 people with schizophrenia and about 113,000 without the disease. Researchers are likely to find hundreds of additional genetic variations associated with the disease as the number of patients sampled grows, says psychiatrist Kenneth Kendler of the Virginia Institute for Psychiatric and Behavioral Genetics in Richmond, a co-author on the study. Identifying the variants themselves is unlikely to lead directly to new drug targets, Kendler says. Instead, the hope is that researchers at Broad and elsewhere will be able to use those data to reveal clusters of genetic variation, like placing pins on a map, he says. © 2014 American Association for the Advancement of Science.
by Bethany Brookshire Even when we love our jobs, we all look forward to some time away. During the week, as stress builds up and deadlines accumulate, Friday looks better and better. Then, with a sigh of relief, the weekend arrives. But come Monday, it seems like the whole weight of responsibility just comes crashing down again. It’s not just you. Rats feel it, too. Rats given a two-day break from a stressful procedure show more signs of strain on “Monday” than rats who never got the weekend, researchers report July 11 in PLOS ONE. The results show that in some cases, an unpredictable getaway can cause more stress than just working through the pressure. Wei Zang, J. Amiel Rosenkranz and colleagues at the Rosalind Franklin University of School of Medicine and Science in Chicago wanted to understand how changes to a stressful situation alter an animal’s response to stress. Normally, when rats are exposed over and over to a stress such as a restraint (in which a rat is placed in a small tube where it can’t turn around or get out), they begin to get used to the stress. Over a few days, rats stop avoiding the tube and stay calmly in the restraint without struggling, until they are set free. Hormones like corticosterone — which spikes in response to stress — go down. This phenomenon is called habituation. Zhang and colleagues wanted to see what happens when this pattern of stress is interrupted. They restrained rats for 20 minutes each for five days. By day five, the animals were hanging out comfortably in the tubes. Then, the scientists introduced an interruption: They gave half of the rats two days off, a science-induced weekend. The scientists continued to restrain the other group of rats daily. © Society for Science & the Public 2000 - 2013
Link ID: 19872 - Posted: 07.23.2014
By Janice Lynch Schuster I have never been one to visit a doctor regularly. Even though I had accumulated my share of problems by age 50— arthritic knees, poor hearing — I considered myself to be among the mostly well. But 19 months ago I developed a perplexing problem that forced me to become not only a regular patient but also one of the millions of Americans with chronic pain who struggle to find relief, in part through treatment with opioids. The trouble began with a terrible and persistent pain in my tongue. It alternately throbbed and burned, and it often hurt to eat or speak. The flesh looked red and irritated, and no amount of Orajel or Sensodyne relieved it. My doctor suggested I see my dentist; my dentist referred me to an oral surgeon. The surgeon thought the problem was caused by my being “tongue-tied,” a typically harmless condition in which the little piece of tissue under the tongue, called the frenulum, is too short. It seems I have always had this condition but had never noticed, because it hadn’t affected my ability to eat or speak. Now things had changed. The doctor recommended a frenectomy, a procedure to remove the frenulum and relieve tension on the tongue. “Just a snip,” he promised. It sounded trivial, and I was eager to be done with it. Although I make a living writing about health care, I didn’t even bother to do a Web search on the procedure. It never occurred to me that “a snip” might entail some risks. I trusted the oral surgeon.
Keyword: Pain & Touch
Link ID: 19871 - Posted: 07.23.2014
By Sid Perkins Forget the phrase “blind as a bat.” New experiments suggest that members of one species of these furry flyers—Myotis myotis, the greater mouse-eared bat—can do something no other mammal is known to do: They detect and use polarized light to calibrate their long-distance navigation. Previous research hinted that these bats reset their magnetic compass each night based on cues visible at sunset, but the particular cue or cues hadn’t been identified. In the new study, researchers placed bats in boxes in which the polarization of light could be controlled and shifted. After letting the bats experience sundown at a site near their typical roost, the team waited until after midnight (when polarized light was no longer visible in the sky), transported the animals to two sites between 20 and 25 kilometers from the roost, strapped radio tracking devices to them, and then released them. In general, bats whose polarization wasn’t shifted took off for home in the proper direction. But those that had seen polarization shifted 90° at sunset headed off in directions that, on average, pointed 90° away from the true bearing of home, the researchers report online today in Nature Communications. It’s not clear how the bats discern the polarized light, but it may be related to the type or alignment of light-detecting pigments in their retinas, the team suggests. The bats may have evolved to reset their navigation system using polarized light because that cue persists long after sunset and is available even when skies are cloudy. Besides these bats (and it’s not known whether other species of bat can do this, too), researchers have found that certain insects, birds, reptiles, and amphibians can navigate using polarized light. © 2014 American Association for the Advancement of Science
By Katherine Harmon Courage Octopuses do the darndest things. Like kill their mate during mating—by strangling him with three arms, according to new observations from the wild. Enterprising scientists Christine Huffard and Mike Bartick watched wild octopuses in action. They found that, for males, mating can be a dangerous game. Especially when your lady has long limbs. Some of the more dicey encounters are detailed in a new paper, published online July 11 in Molluscan Research. Hold on a second, you say. Strangling octopuses? Octopuses don’t even have necks—or inhale air. So how, exactly, does that work? The strangulation seems to happen when “an octopus wraps at least one arm around the base of the mantle of the competitor” (or mate), Huffard wrote in 2010. This constriction then keeps the octopus from taking in fresh water to run past its gills—starving the animal of its oxygen source. Octopuses are not known to get cuddly with one another on a day-to-day basis. In fact, “octopuses touch each other with their arms primarily in the context of mating and aggression,” the researchers write. And in this case it seems to have been both. Huffard came across a pair of mating day octopuses (Octopus cyanea) near Fiabacet Island in Indonesia. The female, as is often the case in this species, was larger—with a body about seven-and-a-half inches long; the male was closer to six inches long. They were positioned on a reef, outside the female’s den, the male’s mating arm (hectocotylus) inserted into the female’s mantle from a (presumably) safe distance. © 2014 Scientific American
Keyword: Sexual Behavior
Link ID: 19869 - Posted: 07.23.2014
By Virginia Morell Dogs, most of us think, have the best noses on the planet. But a new study reveals that this honor actually goes to elephants. The power of a mammal’s sniffer hinges on the number and type of its olfactory receptor genes. These genes are expressed in sensory cells that line the nasal cavity and are specialized for detecting odor molecules. When triggered, they set off a cascade of signals from the nose to the brain, enabling an animal to identify a particular smell. In the new study, scientists identified and examined olfactory receptor genes from 13 mammalian species. The researchers found that every species has a highly unique variety of such genes: Of the 10,000 functioning olfactory receptor genes the team studied, only three are shared among the 13 species. Perhaps not surprisingly, given the length of its trunk, the African elephant has the largest number of such genes—nearly 2000, the scientists report online today in the Genome Research. In contrast, dogs have only 1000, and humans and chimpanzees, less than 400—possibly because higher primates rely more on their vision and less on their sense of smell. The discovery fits with another recent study showing that Asian elephants are as good as mice (which have nearly 1300 olfactory receptor genes) at discriminating between odors; dogs and elephants have yet to be put to a nose-to-trunk sniffer test. Other research has also shown just how important a superior sense of smell is to the behemoths. A slight whiff is all that’s necessary, for instance, for elephants, such as those in the photo above, to distinguish between two Kenyan ethnic groups—the Maasai, who sometimes spear them, and the Kamba, who rarely pose a threat. They can also recognize as many as 30 different family members from cues in their urine. © 2014 American Association for the Advancement of Science.
Keyword: Chemical Senses (Smell & Taste)
Link ID: 19868 - Posted: 07.23.2014
By PETER ANDREY SMITH Sweet, salty, sour and bitter — every schoolchild knows these are the building blocks of taste. Our delight in every scrumptious bonbon, every sizzling hot dog, derives in part from the tongue’s ability to recognize and signal just four types of taste. But are there really just four? Over the last decade, research challenging the notion has been piling up. Today, savory, also called umami, is widely recognized as a basic taste, the fifth. And now other candidates, perhaps as many as 10 or 20, are jockeying for entry into this exclusive club. “What started off as a challenge to the pantheon of basic tastes has now opened up, so that the whole question is whether taste is even limited to a very small number of primaries,” said Richard D. Mattes, a professor of nutrition science at Purdue University. Taste plays an intrinsic role as a chemical-sensing system for helping us find what is nutritious (stimulatory) and as a defense against what is poison (aversive). When we put food in our mouths, chemicals slip over taste buds planted into the tongue and palate. As they respond, we are thrilled or repulsed by what we’re eating. But the body’s reaction may not always be a conscious one. In the late 1980s, in a windowless laboratory at Brooklyn College, the psychologist Anthony Sclafani was investigating the attractive power of sweets. His lab rats loved Polycose, a maltodextrin powder, even preferring it to sugar. That was puzzling for two reasons: Maltodextrin is rarely found in plants that rats might feed on naturally, and when human subjects tried it, the stuff had no obvious taste. More than a decade later, a team of exercise scientists discovered that maltodextrin improved athletic performance — even when the tasteless additive was swished around in the mouth and spit back out. Our tongues report nothing; our brains, it seems, sense the incoming energy. © 2014 The New York Times Company
Keyword: Chemical Senses (Smell & Taste)
Link ID: 19867 - Posted: 07.22.2014
Sarah C. P. Williams The wheezing, coughing, and gasping for breath that come with a sudden asthma attack aren’t just the fault of an overactive immune system. A particularly sensitive bundle of neurons stretching from the brain to the lungs might be to blame as well, researchers have found. Drugs that alter these neurons could provide a new way to treat some types of asthma. “This is an exciting confirmation of an idea that’s been around for decades,” says Allison Fryer, a pulmonary pharmacology researcher at Oregon Health & Science University in Portland, who was not involved in the new study. An asthma attack can be brought on by a variety of triggers, including exercise, cold temperatures, pollen, and dust. During an attack, a person’s airways become inflamed, mucus clogs their lungs, and the muscles surrounding their airways tighten. Asthma is often considered a disease of the immune system because immune cells go into overdrive when they sense a trigger and cause inflammation. But a bundle of nerves that snakes through the neck and chest, the vagus nerve, has long been suspected to play a role; the cells it contains, after all, control the airway muscles. Studying which cell types and molecular pathways within the thick nerve bundle are involved, though, has been tough—the vagus contains a multitude of different cells that are physically intertwined. Working together at the Howard Hughes Medical Institute’s Janelia Farm Research Campus in Ashburn, Virginia, neurobiologists Dimitri Tränkner, now at the University of Utah in Salt Lake City, and Charles Zuker of Columbia University turned to genetics to work out the players. They selectively shut off different sets of the neurons in mice based on which genes each neuron expressed, rather than their physical location. Then, through a series of injections, they gave the animals an egg white allergy that causes asthmalike symptoms. © 2014 American Association for the Advancement of Science
Link ID: 19866 - Posted: 07.22.2014
By DONALD G. MCNEIL Where was I? Sorry — must have nodded off for a decade. Ten years ago, I spent two nights in a sleep lab at SUNY Downstate Medical Center, taking the test for sleep apnea, and wrote about it for Science Times. Back then, “sleep technicians” wired me up like the Bride of Frankenstein: 15 sensors glued or clamped to my scalp, lip, eye sockets, jaw, index finger, chest and legs, two belts around my torso, and a “snore mike” on my neck. As I slept, an infrared camera watched over me. And I ended up spending 23 hours in that hospital bed because the test wasn’t over until you could lie in a dark room for 20 minutes without dozing off. I had such a sleep deficit that I kept conking out, not just all night, but all the next day. So this year, when a company called NovaSom offered to let me try out a new home sleep-test kit that promises to streamline the process, I said yes. In the decade since my ordeal, the pendulum has swung sharply in the direction of the home test, said Dr. M. Safwan Badr, past president of the American Academy of Sleep Medicine, which first recognized home testing for apnea in 2007. Insurers prefer it because it costs only about $300, about one-tenth that of a hospital test, and many patients like it, too. “Lots of people are reluctant to let a stranger watch them sleep,” said Dr. Michael Coppola, a former president of the American Sleep Apnea Association who is now the chief medical officer at NovaSom. Doctors estimate that 18 million Americans have moderate to severe apnea and 75 percent of them do not know it. Home testing is not recommended for those with heart failure, emphysema, seizures and a few other conditions. And because it does not record brain waves as a hospital lab does, a home test can be fooled by someone who just lies awake all night staring at the ceiling. But it’s useful for many people who exhibit the warning signs of apnea, such as waking up exhausted after a full night’s sleep or dozing off at the wheel in bright daylight. And severe apnea can be lethal: starving the brain of oxygen all night quadruples the risk of stroke. © 2014 The New York Times Company
Link ID: 19865 - Posted: 07.22.2014
Most of the genetic risk for autism comes from versions of genes that are common in the population rather than from rare variants or spontaneous glitches, researchers funded by the National Institutes of Health have found. Heritability also outweighed other risk factors in this largest study of its kind to date. About 52 percent of the risk for autism was traced to common and rare inherited variation, with spontaneous mutations contributing a modest 2.6 percent of the total risk. “Genetic variation likely accounts for roughly 60 percent of the liability for autism, with common variants comprising the bulk of its genetic architecture,” explained Joseph Buxbaum, Ph.D., of the Icahn School of Medicine at Mount Sinai (ISMMS), New York City. “Although each exerts just a tiny effect individually, these common variations in the genetic code add up to substantial impact, taken together.” Buxbaum, and colleagues of the Population-Based Autism Genetics and Environment Study (PAGES) Consortium, report on their findings in a unique Swedish sample in the journal Nature Genetics, July 20, 2014. “Thanks to the boost in statistical power that comes with ample sample size, autism geneticists can now detect common as well as rare genetic variation associated with risk,” said Thomas R. Insel, M.D., director of the NIH’s National Institute of Mental Health (NIMH). “Knowing the nature of the genetic risk will reveal clues to the molecular roots of the disorder. Common variation may be more important than we thought.”
By JAN HOFFMAN As it has for decades, the Centers for Disease Control and Prevention last week released its annual National Health Interview Survey on the health of Americans. But this year, there was a difference: For the first time, the respondents were asked about their sexual orientation. Of 34,557 adults ages 18 and older, the survey reported, 1.6 percent said they were gay or lesbian. Some critics say the numbers are low, but they fall in the range of other surveys. In the new survey, however, only 0.7 percent of respondents described themselves as bisexual; other studies have reported higher numbers. Adults who identified themselves as gay, lesbian or bisexual reported some different behaviors and concerns — for example, more alcohol consumption and cigarette smoking — than those who said they were straight. But it can be difficult to elicit information that many people consider private. The New York Times spoke about such challenges with Gary J. Gates, a demographer at the Williams Institute at the U.C.L.A. School of Law, which focuses on law and policy issues related to sexual orientation and gender identity. Some of Dr. Gates’s findings were echoed in the new survey. This interview was edited and condensed. Q.How was this survey conducted? A.Survey takers had a computer that guided them through questions which they asked the respondent in person, and they used flash cards to show them potential answers. Q.Why do you think the figure for bisexuality was lower than in other surveys? A.There is evidence that bisexuals perceive more stigma and discrimination than gay and lesbian people. They are much less likely to tell important people around them that they are bisexual. © 2014 The New York Times Company
Keyword: Sexual Behavior
Link ID: 19862 - Posted: 07.22.2014
By HENRY L. ROEDIGER III TESTS have a bad reputation in education circles these days: They take time, the critics say, put students under pressure and, in the case of standardized testing, crowd out other educational priorities. But the truth is that, used properly, testing as part of an educational routine provides an important tool not just to measure learning, but to promote it. In one study I published with Jeffrey D. Karpicke, a psychologist at Purdue, we assessed how well students remembered material they had read. After an initial reading, students were tested on some passages by being given a blank sheet of paper and asked to recall as much as possible. They recalled about 70 percent of the ideas. Other passages were not tested but were reread, and thus 100 percent of the ideas were re-exposed. In final tests given either two days or a week later, the passages that had been tested just after reading were remembered much better than those that had been reread. What’s at work here? When students are tested, they are required to retrieve knowledge from memory. Much educational activity, such as lectures and textbook readings, is aimed at helping students acquire and store knowledge. Various kinds of testing, though, when used appropriately, encourage students to practice the valuable skill of retrieving and using knowledge. The fact of improved retention after a quiz — called the testing effect or the retrieval practice effect — makes the learning stronger and embeds it more securely in memory. This is vital, because many studies reveal that much of what we learn is quickly forgotten. Thus a central challenge to learning is finding a way to stem forgetting. © 2014 The New York Times Company
Keyword: Learning & Memory
Link ID: 19861 - Posted: 07.21.2014