Jeff Hecht It's Californian ground squirrel versus rattlesnake in a potentially lethal showdown. But the squirrel has a secret weapon that until now has remained invisible to the human eye. The ground squirrel heats up its tail then waves it in the snake's face - a form of harassment that confuses the rattler, which has an infrared sensing organ for detecting small mammals. This defensive tactic remained invisible to biologists until they looked at the animals through an infrared video camera. Now they believe that many other animals might be using infrared weaponry to ward off potential predators. Young California ground squirrels (Spermophilus beecheyi) are easy prey for snakes, so protective adults harass the predators while puffing up their tails and wagging them. Graduate student Aaron Rundus and his supervisor Donald Owings of the University of California, Davis, wondered how this might affect the snakes’ interaction with the adult squirrels. So he borrowed a $35,000 infrared camera from another scientist and spied on squirrel-snake stand-offs. © Copyright Reed Business Information Ltd.

Keyword: Vision
Link ID: 10591 - Posted: 06.24.2010

Caffeine may help older women ward off mental decline, research suggests. French researchers compared women aged 65 and older who drank more than three cups of coffee per day with those who drank one cup or less per day. Those who drank more caffeine showed less decline in memory tests over a four year period. The study, published in the journal Neurology, raises the possibility that caffeine may even protect against the development of dementia. The results held up even after factors such as education, high blood pressure and disease were taken into account. Caffeine is a known psychostimulant, but this study appears to suggest its effects may be more profound. However, lead researcher Dr Karen Ritchie of the French National Institute for Health and Medical Research warned against jumping to premature conclusions. She said: "While we have some ideas as to how this works biologically, we need to have a better understanding of how caffeine affects the brain before we can start promoting caffeine intake as a way to reduce cognitive decline. "But the results are interesting - caffeine use is already widespread and it has fewer side effects than other treatments for cognitive decline, and it requires a relatively small amount for a beneficial effect." The study, which involved 7,000 women, did not find that caffeine consumers had lower rates of dementia. Dr Ritchie said: "We really need a longer study to look at whether caffeine prevents dementia; it might be that caffeine could slow the dementia process rather than preventing it." She said it was not clear why the protective effect did not seem to apply to men. (C)BBC

Keyword: Learning & Memory; Drug Abuse
Link ID: 10590 - Posted: 08.10.2007

David Perlman, Chronicle Science Editor A trove of fossil skulls, teeth and bones more than a million years old and discovered in Africa has opened a new controversy over the lineage of our early human ancestors: Just who descended from whom, and how long ago did they do it? Scientists have long believed that two species of humanlike creatures were direct forebears of our own Homo sapiens tribe, but the discoverers of the newly described fossils suggest the two species were not directly ancestral at all. Instead, the anthropologists conclude, they lived at the same time in the same African lake region for at least half a million years, and one of them may well have been more apelike than human. The finds from the Lake Turkana region of Kenya were announced Wednesday by a team of anthropologists headed by Maeve Leakey, the legendary fossil hunter, plus her anthropologist daughter Louise and her principal colleague, Fred Spoor of University College London. But other anthropologists promptly challenged the team's conclusions. Such disputes are by no means rare in the contentious field of paleoanthropology, for ancient bones must often be dug from solid rock and are more often than not in bad shape for positive analysis. Their significance is often argued for years. © 2007 Hearst Communications Inc.

Keyword: Evolution
Link ID: 10589 - Posted: 06.24.2010

Kerri Smith The way in which antidepressants exert their effects on brain cells has been revealed by two separate teams of researchers working independently of each other. Antidepressants work by preventing neurons in the brain from importing certain chemicals, such as dopamine and serotonin, which are used to pass messages from cell to cell. The route by which these chemicals are imported depends on passageways in the outer membrane of the cells called transporter proteins, and it is on these passageways that the antidepressants exert their influence. But how exactly they hold up the process has remained a mystery since the drugs were discovered 45 years ago, says Les Iversen, a pharmacologist at the University of Oxford, UK. To resolve the mystery, both teams — one led by Eric Gouaux of Oregon Health and Science University in Portland and the other based at New York University and led by Da-Neng Wang — set out to understand what happens when antidepressants lock onto a transporter at the most fundamental level. They zoomed in on the transporters' molecular structures as revealed at atomic resolution through X-ray crystallography. The researchers couldn't use human transporter proteins because they are difficult to isolate and fall apart easily. Instead they used an equivalent found in bacteria called LeuT. They then selected drugs from a class called tricyclic antidepressants and created crystals in which the drug and the transporter were bound together. Gouaux's team used a drug called clomipramine while Wang's used a similar compound called desipramine. ©2007 Nature Publishing Group

Keyword: Depression
Link ID: 10588 - Posted: 06.24.2010

Heidi Ledford A US government-appointed scientific panel has said it has "some concern" that a compound found in many plastics may cause neural and behavioural abnormalities in infants and children at concentrations normally found in humans. But the panel found negligible concern that those exposed to typical levels of the compound, called bisphenol A, would develop reproductive problems or birth defects. The panel, which announced its findings on Wednesday 8 August, was convened by a division of the National Institute of Environmental Health Sciences (NIEHS) called the Center for the Evaluation of Risks to Human Reproduction (CERHR). Its report will now undergo review by the US National Toxicology Program and there will be two additional public comment periods before it is finalized. At that point it could serve as the basis for subsequent regulation of bisphenol A. The findings stand in stark contrast to the conclusions of an independent scientific panel assembled by Jerrold Heindel, a scientist who is also at the NIEHS. That panel published a consensus statement a week ago, citing its conclusion that prenatal or neonatal bisphenol A exposure alters the prostate, breasts, testes, mammary glands, body size, and behaviour later in life. The consensus statement was published along with two new bisphenol A studies to appear in the journal Reproductive Toxicology1,2, but the reports came too late for consideration by the CERHR panel, says its chair, Robert Chapin of Pfizer. ©2007 Nature Publishing Group

Keyword: Development of the Brain
Link ID: 10587 - Posted: 06.24.2010

Using electrical energy to zap cancer cells may sound like a strange idea. But clinical trials at twelve major hospitals around the country are now testing it against the deadliest form of brain cancer. In this ScienCentral News video, you'll hear from one study participant who a year ago was given only six months to live. Michael Quatrano's head is covered with electrodes and he's tethered to cable-box-sized electrical device and battery pack -- minor inconveniences after the surgery, radiation and chemotherapy that failed to stop his aggressive brain tumor from growing. Last August, Quatrano was diagnosed with Glioblastoma Multiforme (GBM), the most common and lethal type of brain cancer. He'd had periodic headaches before, so when he went to the emergency room for what he thought was a migraine, he expected to be treated with pain medication. "I thought I was going for a regular migraine and they said I had cancer," says Quatrano. "[The surgeon] went in my head and cut it and drained it as much as he could. And he told me that it looked really bad and I had six months to live. Right away, I've had people in my family that's had cancer, so I knew I've got to fight. So I don't give up." Quatrano had radiation and chemotherapy to shrink the tumor. "Then what happened, two weeks after I stopped, the tumor grew again," he says."This was like the last alternative. And luckily, it's working out." © ScienCentral, 2000-2007.

Keyword: Miscellaneous
Link ID: 10586 - Posted: 06.24.2010

By Krista Zala Give your skeletal system some credit. Not only do your bones keep you upright, they produce red and white blood cells, store minerals, and help control pH. But that's not all: According to a new study, bones secrete a protein called osteocalcin that regulates sugar and fat absorption. The finding qualifies osteocalcin as a hormone, meaning the skeleton can now add being an endocrine organ to its impressive list of accomplishments. There have already been hints that the skeletal system and the hormone-releasing endocrine system are intertwined. Gerard Karsenty, a geneticist at Columbia University, showed that fat cells regulate bone mass, for example, by releasing the hormone leptin, which affects the number of bone-building osteoblast cells. Considering the prevalence of feedback systems in the body, he and colleagues wondered whether bones might release their own hormones to influence fat metabolism. They knew that bones secrete a protein called osteocalcin, which helps pack calcium into the skeleton, but because no one had observed this protein acting elsewhere in the body, it was not classified as a hormone. Still, Karsenty and colleagues observed that mice unable to make osteocalcin grow obese, suggesting it might work as a hormone. So Karsenty's team genetically engineered one set of mice to produce loads of osteocalcin and another set not to make it at all. When fed regular diets, the mice making extra osteocalcin had lower-than-normal blood glucose levels and higher insulin levels than regular mice. © 2007 American Association for the Advancement of Science.

Keyword: Hormones & Behavior; Obesity
Link ID: 10585 - Posted: 06.24.2010

Coping well with stress can cut the risk of a stroke by almost a quarter, research shows. A University of Cambridge team based their conclusion on a seven-year study of more than 20,000 people. The study, published in the journal Stroke, recorded 452 strokes and more than 100,000 stressful life events among the participants. Those who were able to take a well-rounded approach to problems had a 24% lower risk of stroke. This group were said to have a good sense of coherence - a term coined following research into the experiences of survivors of concentration camps. Lead researcher Dr Paul Surtees, from the University of Cambridge, said: "Our findings suggest that people who are able to adapt more rapidly to stressful circumstances in their lives had a lower risk of stroke. "Whilst many questions remain to be answered by further research, this evidence raises the possibility that improving our ability to respond to stress may have benefits for vascular health." Dr Surtees said the relationship between stress and stroke was probably complex. However, he said there was a wealth of anecdotal evidence suggesting a link between the two. For instance, in the three months following the Kobe earthquake in Japan in 1995 stroke rates among the local population rose by 90%. (C)BBC

Keyword: Stress; Stroke
Link ID: 10584 - Posted: 08.09.2007

Women do not see macho men as a sound bet for a long-term partnership, preferring those with more feminine features, a study suggests. Men with masculine features like large noses and small eyes were seen as less warm, less faithful and worse parents than more feminine counterparts. Some 400 British men and women made judgements after viewing photographs in which the features were subtly altered. The study appears in the journal Personality and Individual Differences. Lead author Dr Lynda Boothroyd of Durham University said: "This research shows a high amount of agreement between women about what they see, personality-wise, when asked to judge a book by its cover. "They may well use that impression of someone to decide whether or not to engage with that person. That decision-making process all depends on what a woman is looking for in a relationship at that stage of her life." Some 400 British men and women completed the web-based test which put a pair of pictures in front of them. Participants were asked to judge the faces on the following categories: dominance, ambition, wealth, faithfulness, commitment, parenting and warmth. They did so by clicking on the point of a scale. The differences were subtle but apparent to the trained eye. The feminine face had more curved eyebrows, an arched forehead and slightly higher cheekbones. He also wore a hint of a smile, as women smile more often than men, the researchers said. (C)BBC

Keyword: Sexual Behavior
Link ID: 10583 - Posted: 08.09.2007

By ERIC NAGOURNEY Just can’t manage to nail down the subjunctive tense in French or the difference between the Spanish verbs for “to be”? Blame your Heschl’s gyrus — or at least your left one, anyway. That is a tiny part of the brain that appears to play an important role in how well adults can learn another language, a new study finds. Writing online in the journal Cerebral Cortex, researchers said people who had a larger left Heschl’s gyrus seemed to have an easier time picking up foreign languages. As a practical matter, a beefier H.G., as it is known, may not really help with the subjunctive or the difference between “ser” and “estar” in Spanish. For this study, the researchers, led by Dr. Patrick C. M. Wong of Northwestern, were focusing on the ability to discern pitch, a key element of tonal languages, not vocabulary. In tonal languages like Chinese, which are spoken by most of the world’s population, the same word can have different meanings, depending on how it is inflected. Copyright 2007 The New York Times Company

Keyword: Language
Link ID: 10582 - Posted: 06.24.2010

By NATALIE ANGIER In this country, the most popular cosmetic surgery procedure is liposuction: doctors vacuum out something like two million pounds of fat from the thighs, bellies, buttocks, jowls and man-breasts of 325,000 people a year. What happens to all that extracted adipose tissue? It’s bagged and disposed of as medical waste; or maybe, given the recent news about socially contagious fat, it’s sent by FedEx to the patients’ old college chums. But one thing the fat surely is not, and that is given due thanks for serving as scapegoat, and for a job well done. We are now in what feels like the 347th year of the fastidiously vilified “obesity epidemic.” Health officials repeatedly warn that everywhere in the world people are gaining too much weight and putting themselves at risk of diabetes, high blood pressure, heart disease and other obesity-linked illnesses, not to mention taking up more than their fair share of molded plastic subway seat. It’s easy to fear and despise our body fat and to see it as an unnatural, inert, pointless counterpoint to all things phat and fabulous. Yet fat tissue is not the problem here, and to castigate fat for getting too big and to blame it for high blood pressure or a wheezing heart is like a heavy drinker blaming the liver for turning cirrhotic. Just as the lush’s liver was merely doing its hepatic best to detoxify the large quantities of liquor in which it was doused, and just as the alcoholic would have been far worse off had the liver not been playing Hepa-filter in the first place, so our fat tissue, by efficiently absorbing the excess packets of energy we put in our mouths, has our best interests at heart. Copyright 2007 The New York Times Company

Keyword: Obesity
Link ID: 10581 - Posted: 06.24.2010

Michael Hopkin Two fossils unearthed in Kenya have added a new dimension to our view of life at the birth of our Homo genus. They show that two ancestral human species seem to have lived cheek-by-jowl in the same area, much as gorillas and chimpanzees do today. Both skull fragments were found by anthropologists digging near Kenya's Lake Turkana, adding to the impressive list of early human fossils unearthed here. One of the fossils, an upper jawbone from the species Homo habilis, is dated at 1.44 million years, much younger than most fossils of this species. The other fossil is an almost complete — but faceless — Homo erectus skull. Dated at 1.55 million years, the skull is far smaller than any other from this species — suggesting to the researchers that, as is the case with modern gorillas, there was a large size differences between the sexes in H. erectus. The fact that these two species seem to have been contemporaries is a surprise to anthropologists, say Fred Spoor of University College London and his colleagues, who discovered the hominin fossils seven years ago and now describe them in this week's Nature. ©2007 Nature Publishing Group

Keyword: Evolution
Link ID: 10580 - Posted: 06.24.2010

By the time they reached adulthood, graduates of an intensive early childhood education program for poor children showed higher educational attainment, lower rates of serious crime and incarceration, and lower rates of depressive symptoms than did non-participants in the program, reported researchers in a study funded in part by the National Institutes of Health. The Child-Parent Centers (CPC) program in the Chicago Public School System provided intensive instruction in reading and math from pre-kindergarten through third grade, combined with frequent educational field trips. The children’s parents received job skills training, parenting skills training, educational classes and social services. They also volunteered in their children’s classrooms, assisted with field trips and attended parenting support groups. The CPC program is distinct from the federally funded Head Start program. “These results strongly suggest that comprehensive early education programs can have benefits well into adult life,” said Duane Alexander, Director of the National Institute of Child Health and Human Development, the NIH institute that funded the study. “A comparatively small investment early in life is associated with gains in education, economic standing, mental health, and other areas.” The researchers followed the children from ages 3 or 4 through age 24 to assess the possible benefits of the CPC program in terms of the children’s educational achievement, need for remedial education, involvement with the child welfare and foster care system, economic status, involvement with the criminal justice system, health status and mental health. The study appears in the August Archives of Pediatrics & Adolescent Medicine.

Keyword: Development of the Brain; Depression
Link ID: 10579 - Posted: 06.24.2010

Roxanne Khamsi Educational DVDs may hinder rather than help a young child's learning. Infants who watch DVDs such as Brainy Baby and Baby Einstein know fewer words than those who do not watch such programmes, a new study suggests. In recent years the popularity of such infant programmes has soared, particularly in the US. Parents hope the programmes, which typically consist of brief dialogue and picture sequences, will boost the learning ability of children as young as eight months old, even though the American Academy of Pediatrics has recommended that youngsters not watch television until two years of age. To find out what effect these programmes have, Dimitri Christakis at the University of Washington in Seattle, US, and his colleagues contacted about 500 families with a child born in the previous 16 months. During telephone interviews – which each lasted around 45 minutes – parents heard a list of about 90 words, such as "truck" and "cookie", and indicated which their 8- to 16-month-old children understood. They also gave other details, including how much they read to their children, and the amount and type of television their youngsters watched. The results contradict claims that baby DVDs help toddlers to communicate with their parents. After controlling for other factors, such as parents' educational status and the number of children per household, the analysis revealed that for every hour per day spent watching baby DVDs, toddlers understood an average of six to eight words fewer than those who did not view them. On average the children recognised about 25 words, although the number varied according to age. © Copyright Reed Business Information Ltd

Keyword: Development of the Brain; Language
Link ID: 10578 - Posted: 06.24.2010

By Vaudine England A study by doctors in Hong Kong has concluded that epilepsy can be induced by the Chinese tile game of mahjong. The findings, published in the Hong Kong Medical Journal, were based on 23 cases of people who had suffered mahjong-induced seizures. The report's four authors, from Hong Kong's Queen Mary Hospital, said the best prevention - and cure - was to avoid playing mahjong. The study led the doctors to define mahjong epilepsy as a unique syndrome. Eileptic seizures can be provoked by a wide variety of triggers, but one cause increasingly evident to researchers is the playing - or even watching - of mahjong. This Chinese tile game, played by four people round a table, can involve gambling and quickly becomes compulsive. The game, which is intensely social and sometimes played in crowded mahjong parlours, involves the rapid movement of tiles in marathon sessions. The doctors conclude that the syndrome affects far more men than women; that their average age is 54; and that it can hit sufferers anywhere between one to 11 hours into a mahjong game. They say the attacks were not just caused by sleep deprivation or gambling stress. (C)BBC

Keyword: Epilepsy
Link ID: 10577 - Posted: 08.06.2007

US scientists have genetically modified mice to exhibit both the anatomical and behavioural defects associated with the complex condition schizophrenia. Previous studies that rely on drugs can only mimic the symptoms of the disease, such as delusions and paranoia. But the new work, based on a key genetic change, could aid a much greater understanding of the disease. The Johns Hopkins University study appears in Proceedings of the National Academy of Sciences. Animal models of schizophrenia have been hard to design since many different causes underlie this disease. However, the Johns Hopkins team were able to take advantage of the recent discovery of a major risk factor for the disease. Scientists pinpointed a key gene - dubbed DISC 1 - which makes a protein that helps nerve cells assume their proper positions in the brain. The Johns Hopkins team generated mice that make an incomplete, shortened form of the DISC 1 protein in addition to the regular type. The short form of the protein attaches to the full-length one, disrupting its normal duties. As these mice matured, they became more agitated when placed in an open field, had trouble finding hidden food, and did not swim as long as regular mice - behaviours that echo the hyperactivity, smell defects and apathy observed in schizophrenia patients. Magnetic resonance imaging (MRI) also revealed characteristic defects in brain structure, including enlarged lateral ventricles, a region that circulates the spinal fluid and helps protect against physical trauma. Researcher Professor Akira Sawa said the defects in these mice were not as severe as those typically seen in people with schizophrenia, because more than one gene is required to trigger the clinical disease. (C)BBC

Keyword: Schizophrenia; Genes & Behavior
Link ID: 10576 - Posted: 08.06.2007

By David Biello Female lab mice tend to be docile, passive creatures. But by either genetically shutting down or surgically removing their ability to smell pheromones, scientists transformed them into aggressive, pelvic-thrusting, vocalizing lotharios—without any significant rise in testosterone or other steroid hormones. "The female brain has the neuronal circuit both to control male and female behavior," says molecular neuroscientist Catherine Dulac of Harvard University. "What is sexually dimorphic is the switch that allows one to be silenced." The key to gender-specific behavior, in mice at least, is a cluster of receptors in their noses that allows them to smell pheromones, special chemicals that deliver information about sexual readiness, among other things, between members of the same species. Called the vomeronasal organ (VNO), it connects to the brain and registers the gender of other mice, triggering the appropriate response. But when the researchers genetically disabled the VNO, female mice began to chase their male peers, mount them and attempt to pelvic thrust [see video here ]. "From a behavioral standpoint you could not recognize the animal from being any different than the male," Dulac adds. "All the thinking until now was that female brains can produce feminine behaviors while male brains can produce masculine behaviors, with little or no cross talk between them," says Marc Breedlove, a neuroscientist at Michigan State University in East Lansing. "These results do suggest that, at least for mice, the brain retains circuitry to display both masculine and feminine behaviors into adulthood." © 1996-2007 Scientific American, Inc.

Keyword: Sexual Behavior; Chemical Senses (Smell & Taste)
Link ID: 10575 - Posted: 06.24.2010

By GINA KOLATA IN a way it all seems so obvious. Your friend found a lump in her breast, so you have that long-delayed mammogram. One by one your friends stop smoking, so you stop, too. Of course people are affected by their friends’ habits and their health. But what seems obvious in the abstract can lead to surprising findings. A recent study found that obesity can spread from friend to friend much like a virus. When one person gains weight, close friends tend to gain weight, too. The study, published recently in The New England Journal of Medicine, involved a detailed analysis of a large social network of 12,067 people who had been closely followed for 32 years, from 1971 to 2003. Now, scientists believe that social networks not only can spread diseases, like the common cold, but also may influence many types of behavior — negative and positive — which then affect an individual’s health, as well as a community’s. “In the past few years we have been seeing a network revolution,” says Albert-Laszlo Barabasi, a physics professor at the University of Notre Dame. “People sensed that networks were out there, but they never had large enough data sets to start understanding them in a quantitative fashion.” Copyright 2007 The New York Times Company

Keyword: Obesity
Link ID: 10574 - Posted: 06.24.2010

By EMILY BAZELON Caitlyn & Marguerite sat knee to knee in a sunny room at the Hawks Camp in Park City, Utah. On one wall was a white board with these questions: What’s your favorite vacation and why? What’s your favorite thing about yourself? If you could have any superpower, what would it be? Caitlyn, who is 13, and Marguerite, who is 16 (I’ve used only their first names to protect their privacy), held yellow sheets of paper on which they had written their answers. It was the third day of the weeklong camp, late for icebreakers. But the Hawks are kids with autistic disorders accompanied by a normal or high I.Q. And so the main goal of the camp, run on a 26-acre ranch by a Utah nonprofit organization called the National Ability Center, is to nudge them toward the sort of back and forth — “What’s your favorite video game?” — that comes easily to most kids. Along with Caitlyn and Marguerite, there were nine boys in the camp between the ages of 10 and 18. They also sat across from one another in pairs, with the exception of one 18-year-old who was arguing with a counselor. “All I require is a purple marker,” the boy said over and over again, refusing to write with the black marker he had been given. A few feet away, an 11-year-old was yipping and grunting while his partner read his answers in a monotone, eyes trained on his yellow paper. Another counselor hurried over to them. Marguerite was also reading her answers without eye contact or inflection. “My favorite vacations were to India and Thailand my favorite thing about myself is that I’m nice to people if I could choose any superpower I’d be invisible,” she said in an unbroken stream. She looked up from her paper and past Caitlyn. The girls didn’t look uncomfortable, just unplugged. Copyright 2007 The New York Times Company

Keyword: Autism
Link ID: 10573 - Posted: 06.24.2010

By Christoph Uhlhaas Could you buy a used car online, sight unseen and without a test-drive? How about a plane? A vehicle changes hands on eBay Motors every 60 seconds, including one private business jet that sold for $4.9 million. Every second buyers collectively swap more than $1,839 for products through eBay, sending money to complete strangers with no guarantee that the goods they buy will in fact arrive, let alone in the condition they expect. As a rule, they are not disappointed. To some economists, this is a borderline miracle, because it contradicts the concept of Homo economicus (economic man) as a rational, selfish person who single-mindedly strives for maximum profit. According to this notion, sellers should pocket buyers’ payments and send nothing in return. For their part, buyers should not trust sellers—and the market should collapse. Economist Axel Ockenfels of the University of Cologne in Germany and his colleagues have spent the past several years figuring out why this does not happen. It turns out that humans do not always behave as if their sole concern is their personal financial advantage—and even when they do, they consider social motives in the profit-making equation. As Ockenfels has discovered, a sense of fairness often plays a big role in people’s decisions about what to do with their money and possessions, and it is also an essential part of what drives trust in markets full of strangers such as eBay. © 1996-2007 Scientific American, Inc

Keyword: Emotions
Link ID: 10572 - Posted: 06.24.2010