The study is the largest in the world so far and was performed in collaboration with the Queen Mary University of London. More than 7,600 Swedish twins (men and women) aged 20-47 years responded to a 2005 - 2006 survey of health, behaviour, and sexuality. Seven percent of the twins had ever had a same-sex sexual partner.

"The results show, that familial and public attitudes might be less important for our sexual behaviour than previously suggested", says Associate Professor Niklas Långström, one of the involved researchers. "Instead, genetic factors and the individual's unique biological and social environments play the biggest role. Studies like this are needed to improve our basic understanding of sexuality and to inform the public debate."

The conclusions apply equally well to why people only have sex with persons of the opposite sex as to why we have sex with same-sex partners. However, the conclusions are more difficult to transfer to countries where non-heterosexual behaviour remains prohibited.

Overall, the environment shared by twins (including familial and societal attitudes) explained 0-17% of the choice of sexual partner, genetic factors 18-39% and the unique environment 61-66%. The individual's unique environment includes, for example, circumstances during pregnancy and childbirth, physical and psychological trauma (e.g., accidents, violence, and disease), peer groups, and sexual experiences.

If borne out experimentally, his work could help explode Moore’s Law and could revolutionize computing technology.

Moore’s Law predicts that the number of transistors that can be economically placed on an integrated circuit will double about every two years. But by 2020, Moore’s Law is expected to hit a brick wall, as manufacturing costs rise and transistors shrink beyond the reach of the laws of classical physics.

A solution lies in the fabled molecular switch. If molecules could replace the current generation of transistors, you could fit more than a trillion switches onto a centimeter-square chip. In 1999, a team of researchers at Yale University published a description of the first such switch, but scientists have been unable to replicate their discovery or explain how it worked. Now, Pati believes he and his team may have found the mechanism behind the switch.

Applying quantum physics, he and his group developed a computer model of an organometallic molecule firmly bound between two gold electrodes. Then he turned on the juice.

As the laws of physics would suggest, the current increased along with the voltage, until it rose to a miniscule 142 microamps. Then suddenly, and counterintuitively, it dropped, a mysterious phenomenon known as negative differential resistance, or NDR. Pati was astonished at what his analysis of the NDR revealed.

Up until the 142-microamp tipping point, the molecule’s cloud of electrons had been whizzing about the nucleus in equilibrium, like planets orbiting the sun. But under the bombardment of the higher voltage, that steady state fell apart, and the electrons were forced into a different equilibrium, a process known as “quantum phase transition.”

“I never thought this would happen,” Pati said. “I was really excited to see this beautiful result.”

Why is this important? A molecule that can exhibit two different phases when subjected to electric fields has promise as a switch: one phase is the “zero” and the other the “one,” which form the foundation of digital electronics.

Management Insights, a regular feature of the journal, is a digest of important research in business, management, operations research, and management science. It appears in every issue of the monthly journal.

“Are Overconfident CEOs Born or Made? Evidence of Self-Attribution Bias from Frequent Acquirers” is by Matthew T. Billett and Yiming Qian of the University of Iowa.

Whether to engage in mergers and acquisitions is one of the most important decisions top managers make, the authors write. While many of the factors influencing these decisions may be based on objective financial metrics, there is increasing evidence that behavioral biases play an important role in managerial decision making. The authors explore one such bias—managerial overconfidence— and find evidence suggesting CEOs develop overconfidence through ‘self-attribution bias’ when making merger and acquisition decisions. Individuals subject to self-attribution bias overcredit their role in bringing about good outcomes and underestimate the role of luck.

Consistent with this, they find that CEOs appear to overly attribute their role in successful deals, leading to more deals even though these subsequent deals are value destructive.

They also find evidence that CEOs alter their stock holdings prior to deals in a pattern consistent with overconfidence in the outcome of these subsequent deals.

The authors advise that CEOs be particularly cautious and disciplined when engaging in acquisitions following prior success. Boards and other stakeholders should also ensure that any proposed deal is judged on its own merits and is not justified on the basis of prior CEO success in mergers and acquisitions, they say.

Professors Billett and Zian based their results on a sample of public acquisitions between 1985 and 2002. Over this period, U.S. public companies acquired $3.7 trillion worth of other U.S. public companies.

A team of Penn State researchers has shown for the first time that the entire class of non-magnetic materials, such as those used in some computer components, could have considerably more uses than scientists had thought. The findings are important because they reveal previously unknown information about the structure of these materials, expanding the number of properties that they potentially could have. A material's properties, such as electrical conductivity and mechanical strength, are what determine its usefulness. The research will be published in the journal Physical Review Letters.

A material's properties are determined by its structure, explained Venkatraman Gopalan, a researcher in Penn State's Center for Nanoscale Science, a professor of materials science and engineering, and the project's leader. "If I was out hiking and I found a rock that contained a quartz crystal, I could tell you what properties the crystal can and cannot have just based on what we call its symmetry--the number and arrangement of crystal planes it has. Symmetry results from the way the atoms are arranged in the quartz," he said. "It is an extremely powerful way of understanding our world."

The non-magnetic materials that Gopalan and his colleagues studied were thought to have one of the 32 different crystal symmetries--called point group symmetries--known to exist in nature. On the other hand, magnetic materials have 90 different point group symmetries because their atomic particles have magnetic spins, which can be imagined as tiny loops of current. "Motion is an extremely important aspect of magnetism," said Gopalan. "Magnetism develops in nature as soon as charged particles start moving or spinning."

Scientists long have believed that symmetry allows magnetic materials to have more properties than non-magnetic materials because flipping the direction of spin creates an additional symmetry. But Gopalan's team has shown that non-magnetic materials, theoretically, can have just as many properties as magnetic materials. According to Gopalan, some non-magnetic materials have groups of atoms that distort by twisting or rotating. This slight movement is equivalent to a tiny loop of current and is enough to give the material some additional properties that previously were thought to belong only to magnetic materials.

The researchers tested their theory experimentally using strontium titanate, which is a non-magnetic material. They cooled the material and found that its oxygen atoms responded by twisting into a tighter postion to save energy and space. "The oxygen atoms don't rotate all the way around like a loop of current does in magnetic materials, but theoretical analyses show that they do twist and, therefore, it is possible that these materials could have previously unknown properties," said Gopalan.

Next, the team investigated whether the twisting movement translated into the expression of additional properties. In particular, they predicted and tested for an optical property that they call roto second harmonic generation, which is analogous to a well-known property called magnetic second harmonic generation. Second harmonic generation is found, for example, in the crystals that are used in green laser pointers to convert infrared laser light into green laser light. The group found that the strontium titanate material does have a small amount of roto second harmonic generation.

"Nobody has thought of relating magnetic symmetries to a non-magnetic material like strontium titanate, but that's precisely what our paper does," said Gopalan. "We first did a theoretical analysis in which we applied the symmetry framework that traditionally is used to describe magnetic materials to this vast class of non-magnetic materials. Then we did a laboratory experiment with a particular non-magnetic material and we found that it has a property that previously was thought to belong only to magnetic materials. We suggest that it is possible for the entire class of non-magnetic materials to have more symmetries and more properties than previously have been thought possible."

The team's findings could lead to an explosion of research into new properties of non-magnetic materials and to possible applications of these properties. "These materials are used in hundreds of applications," said Peter Schiffer, associate vice president for research and a professor of physics at Penn State, "but this new work holds great promise for finding many more uses."

"The population was split into two groups, then one of the groups died out 45,000 years ago, long before the first humans began to appear in the region," said Stephan C. Schuster, associate professor of biochemistry and molecular biology at Penn State University and a leader of the research team. "This discovery is particularly interesting because it rules out human hunting as a contributing factor, leaving climate change and disease as the most probable causes of extinction." The discovery will be published later this week in the early online edition of the Proceedings of the National Academy of Sciences (PNAS).

The research marks the first time scientists have dissected the structure of an entire population of extinct mammal by using the complete mitochondrial genome -- all the DNA that makes up all the genes found in the mitochondria structures within cells. Data from this study will enable testing of the new hypothesis presented by the team, that there were two groups of woolly mammoth -- a concept that previously had not been recognized from studies of the fossil record.

The scientists analyzed the genes in hair obtained from individual woolly mammoths -- an extinct species of elephant adapted to living in the cold environment of the northern hemisphere. The bodies of these mammoths were found throughout a wide swathe of northern Siberia. Their dates of death span roughly 47,000 years, ranging from about 13,000 years ago to about 60,000 years ago.

Schuster and Webb Miller, professor of biology and computer science and engineering at Penn State, led the international research team, which includes Thomas Gilbert at the University of Copenhagen in Denmark and other scientists in Australia, Belgium, France, Italy, Russia, Spain, Sweden, the United Kingdom, and the United States. The team includes experts in the fields of genome evolution, ancient DNA, and mammoth paleontology, as well as curators from various natural-history museums.

Another important finding for understanding the extinction processes is that the individuals in each of the two woolly-mammoth groups were related very closely to one another. "This low genetic divergence is surprising because the woolly mammoth had an extraordinarily wide range: from Western Europe, to the Bering Strait in Siberia, to Northern America," Miller said. "The low genetic divergence of mammoth, which we discovered, may have degraded the biological fitness of these animals in a time of changing environments and other challenges."

Our study suggests a genetic divergence of the two woolly-mammoth groups more than 1-million years ago, which is one quarter the genetic distance that separates Indian and African elephants and woolly mammoths," Miller said. The research indicates that the diversity of the two woolly-mammoth populations was as low centuries ago as it is now in the very small populations of Asian elephants living in southern India. "The low genetic divergence of the elephants in southern Indian has been suggested as contributing to the problems of maintaining this group as a thriving population," Schuster said. Intriguingly, the mitochondrial genomes revealed by the researchers are several times more complete than those known for the modern Indian and African Elephants combined.

Whereas studies before this research had analyzed only short segments of the DNA of extinct species, this new study generated and compared 18 complete genomes of the extinct woolly mammoth using mitochondrial DNA, an important material for studying ancient genes. This achievement is based on an earlier discovery of the team led by Miller, Schuster, and co-author Thomas Gilbert, which was published last year and that revealed ancient DNA survives much better in hair than in any other tissue investigated so far. This discovery makes hair, when it is available, a more powerful and efficient source of DNA for studying the genome sequences of extinct animals. Moreover, mammoth hair is found in copious quantities in cold environments and it is not regarded as fossil material of enormous value like bone or muscle, which also carries anatomical information.

"We also discovered that the DNA in hair shafts is remarkably enriched for mitochondrial DNA, the special type of DNA frequently used to measure the genetic diversity of a population," Miller said. The team's earlier study also showed that hair is superior for use in molecular-genetic analysis because it is much easier than bone to decontaminate. Not only is hair easily cleaned of external contamination such as bacteria and fungi, its structure also protects it from degradation, preventing internal penetration by microorganisms in the environment.

An important aspect of the new study is that the hair samples it used had been stored in various museums for many years before being analyzed by the researchers, yet the scientists were able to obtain lots of useful DNA from them. "One of our samples originates from the famous Adams mammoth, which was found in 1799 and has been stored at room temperatures for the last 200 years," Schuster said. This research technique opens the door for future projects to target interesting specimens that were collected a long time ago and are no longer available from modern species, the scientists said. Even the molecular analysis of entire collections seems now possible, an effort that the team calls "Museomics."

"We plan to continue using our techniques to untangle the secrets of populations that lived long ago and to learn what it might have taken for them to survive," Schuster said. "Many of us also have a personal interest in learning as much as we can about how any species of large mammal can go extinct."

Greg Smutzer, director of the Laboratory of Gustatory Psychophysics in the Biology Department of Temple's College of Science and Technology (http://www.temple.edu/biology), has created taste strips similar to breath-freshening strips, but these edible strips contain one of the five basic tastes that are detected by humans — sweet, sour, salty, bitter and monosodium glutamate, which is also known as umami taste.

This research, "A Test for Measuring Gustatory Function," has been published in the June 2 online "Ahead of Print" edition of The Laryngoscope (http://www.thelaryngoscope.com), the journal of the American Laryngological, Rhinological and Otological Society.

The idea was born when a lab equipment repairman who was a friend of Smutzer's stopped by the laboratory more than four years ago and offered him one of the new breath-freshening strips.

He said, "You have to try one of these," Smutzer recalled. "I had never seen the strips before. But as soon as he showed them to me, one of my first thoughts was, this technology would be ideal for a taste test because it is so simple to use."

Smutzer starts by using a combination of two polymers, pullulan and Methocel. His strips are created by dissolving the polymers — in the form of powders — in warm water and then allowing the solution to cool to room temperature. Added into the solution is a small amount of a taste stimulus that will give each strip the desired taste: sodium chloride for salty, sucrose for sweet, ascorbic acid for sour, quinine for bitter, and monosodium glutamate for umami taste.

Once the solution is cool, it is then poured onto Teflon-coated pans and allowed to dry five to six hours in order to produce a clear, thin film. When dry, the films are carefully removed, and cut into one-inch-square strips.

He said that pullulan, a major ingredient of the Listerine breath strips, is tasteless and dissolves within seconds in the mouth. Methocel is added in small amounts to increase the tensile strength of the pullulan films.

The development of the taste strips solves a problem for researchers. According to Smutzer, no standardized method for rapidly measuring taste function in humans is currently available, and taste norms for the human population as a function of age and sex have yet to be determined.

"What is typically done in the lab is a 'sip and spit' test, where a liquid solution is prepared that contains dissolved tastant," Smutzer explained. "You then place a small amount of the solution, maybe half an ounce, into a small cup for the test subject to place into their mouth, swish around and then spit it out."

But this type of test is difficult to administer outside the lab because the solutions have a very short shelf life and are not very portable, he said. Another big problem with the liquid test is that it cannot be effectively used to examine selected regions of the tongue, such as just one side, the front or the back of the tongue.

"It is very difficult to do regional testing with the liquid test because it is tough to concentrate liquid in just one area of the mouth," said Smutzer, who is hoping to commercialize the taste strips. "We can alter the size or thickness of these strips, place them on a desired area of the tongue and allow saliva to dissolve them without causing the tastant to spread over the surface of the tongue."

Since different parts of the tongue may respond to different tastes, or may respond more or less strongly to the same taste stimulus. Smutzer said his taste strips could be used to develop detailed taste maps of the tongue surface, a project he plans to examine in the future.

Another major advantage of this technology, according to Smutzer, is that the strips can measure thresholds for tastants at levels that are from 10 to 100 times lower when compared to a standard "sip and spit" test. These lower threshold values for sweet, sour, salty, bitter or umami taste could be useful for examining taste disturbances in clinical populations where such disturbances have not been previously identified.

Smutzer added that his strips, which are stored at room temperature and have been used up to six months after being produced, could also be beneficial to the pharmaceutical industry, since certain medications can create temporary taste disturbances. He said that subjects could be tested with taste strips during clinical trials to determine whether new drugs or therapies interfere with taste function.

The popularity of golf carts has skyrocketed in recent years, and unfortunately so has the number of golf cart-related injuries. In fact, a new study conducted by researchers in the Center for Injury Research and Policy of The Research Institute at Nationwide Children's Hospital found that the number of golf cart-related injuries rose 132 percent during the 17-year study period.

According to the study, published in the July issue of the American Journal of Preventive Medicine (available online), there were an estimated 148,000 golf cart-related injuries between 1990 and 2006, ranging from an estimated 5,770 cases in 1990 to approximately 13,411 cases in 2006.

As golf carts have become faster and more powerful, they are no longer limited to use on the golf course. In addition to their traditional role, golf carts are now routinely being used at sporting events, hospitals, airports, national parks, college campuses, business parks and military bases. While the study found that the majority of golf cart-related injuries (more than 70 percent) took place at sports or recreational facilities, individuals injured in carts on the street had an increased risk of concussions and were more likely to require hospitalization than individuals injured in other locations.

While the most common cause of injury for all ages was falling or jumping from the cart, study co-author Gary Smith, MD, DrPH, director of the Center for Injury Research and Policy at Nationwide Children's Hospital, and an associate professor of pediatrics at The Ohio State University College of Medicine explained, "Children are even more likely than adults to fall from the golf cart, and these falls are associated with higher rates of head and neck injuries and hospitalizations. Greater efforts are needed to prevent these injuries."

More than 30 percent of golf cart-related injuries involved children under the age of 16.

"Because golf carts are not designed for children and the majority offer no child safety features, we recommend that children under the age of 6 years not be transported in golf carts and that drivers be at least 16 years old to operate the vehicle," said study co-author Tracy Mehan, MA, CPST, research associate in the Center for Injury Research and Policy at Nationwide Children's.

The study recommends that more effective safety features, such as improved passenger restraints and four-wheel brakes, in combination with training programs and safety policies would reduce the overall number of golf cart-related injuries.

"Following a few safety precautions, such as driving at a reasonable speed, wearing seat belts when they are available, braking slowly and considering the terrain and weather conditions can reduce the potential for injuries," said Mehan.

Facilities where golf carts are used can also help prevent golf cart-related injuries by establishing safety policies, requiring driver's licenses and operator training and considering safety when designing the pathways golf carts will be using.

Apparently not, according to a new study that measured individuals' heart recovery rate from minor stress when exposed to a natural scene through a window, the same scene shown on a high-definition plasma screen, or a blank wall. The heart rate of people who looked at the scene through the window dropped more quickly than the others. In fact, the high-definition plasma screen had no more effect than the blank wall.

In addition, the research done through the Human Interaction with Nature and Technological Systems Lab at the University of Washington showed that when people spent more time looking at the natural scene their heart rates tended to decrease more. That was not the case with the plasma screen.

The study, funded by the National Science Foundation, is published in the current issue of the Journal of Environmental Psychology.

"Technology is good and it can help our lives, but let's not be fooled into thinking we can live without nature," said Peter Kahn, a UW associate professor of psychology who led the research team.

"We are losing direct experiences with nature. Instead, more and more we're experiencing nature represented technologically through television and other media. Children grow up watching Discovery Channel and Animal Planet. That's probably better than nothing. But as a species we need interaction with actual nature for our physical and psychological well-being."

Part of this loss comes from what the researchers call environmental generational amnesia. This is the idea that across generations the amount of environmental degradation increases, but each generation views conditions it grew up with as largely non-degraded and normal. Children growing up today in the cities with the worst air pollution often, for example, don't believe that their communities are particularly polluted.

"This problem of environmental generational amnesia is particularly important for children coming of age with current technologies," said Rachel Severson, a co-author of the study and a UW psychology doctoral student. "Children may not realize they are not getting the benefits of actual nature when interacting with what we're calling technological nature."

To see how people reacted to nature and a technological representation of it, the researchers recruited 90 college students to participate in an experiment that had them work on four mental tasks while sitting at a desk in an office. With 30 of the students, the desk faced a window overlooking a campus scene that included a large fountain and trees. For a second group of 30 students, the window was replaced with the plasma screen that showed the same nature scene in real time. For the remaining 30 students, curtains covered the plasma screen and the desk faced a blank wall.

Participants were tested individually. Each was welcomed by a researcher, hooked up to a heart rate monitor and told to wait for five minutes while the researcher stepped out of sight. A camera mounted on the wall near the window or plasma screen was synchronized with the heart monitor and tracked participants' eye movements. At the end of the waiting period, the researcher returned, explained the first task and stepped out of sight. This was repeated for the remaining three tasks and then the subject was told to wait again for five minutes.

Heart recovery rate was based on how quickly each participant's heart rate dropped in the 60 seconds after being told to wait or to have one of the tasks explained. Each person's performance was tallied on the basis of six measurements, once after every task and the two waiting periods. Low-level stress was created by having to deal with another person in a social situation and the anticipation or performance anxiety each might have experienced to do well on the four tasks.

The researchers found that participants with the plasma screen actually looked at it just as often as did those who had the window. However, the window held the students' attention significantly longer than the plasma screen did. When participants spent more time looking at the window, their heart rates decreased faster than on tasks when they spent less time looking at the window. This was not true with the plasma screen.

"I was surprised by this," said Kahn. "I thought the plasma screen would come somewhere between the glass window and the blank wall. This study is important because it shows the importance of nature in human lives and at least one limitation of technological nature.

"In the years ahead, technological nature will get more sophisticated and compelling. But if it continues to replace our interaction with actual nature, it will come at a cost. To thrive as a species, we still need to interact with nature by encountering an animal in the wild, walking along the ocean's edge or sleeping under the enormity of the night sky."

"It's marvelous to be able to do assembly and control at this fine a resolution with such very, very tiny things," said Bruce Donald, a Duke professor of computer science and biochemistry.

Each microrobot is shaped something like a spatula but with dimensions measuring just microns, or millionths of a meter. They are almost 100 times smaller than any previous robotic designs of their kind and weigh even less, Donald added.

Formally known as microelectromechanical system (MEMS) microrobots, the devices are of suitable scale for Lilliputian tasks such as moving around the interiors of laboratories-on-a-chip.

In videos produced by the team, two microrobots can be seen pirouetting to the music of a Strauss waltz on a dance floor just 1 millimeter across. In another sequence, the devices pivot in a precise fashion whenever their boom-like steering arms are drawn down to the surface by an electric charge. This response resembles the way dirt bikers turn by extending a boot heel.

New research summaries describe the group's latest accomplishment: getting five of the devices to group-maneuver in cooperation under the same control system.

"Our work constitutes the first implementation of an untethered, multi-microrobotic system," Donald's team writes in a report to be presented on June 1-2, 2008 during the Hilton Head Workshop on Solid State Sensors, Actuators and Microsystems in South Carolina.

More comprehensive details on how the scientists achieve this "microassembly" will be published later in their report for the Journal of Microelectromechanical Systems.

The research was funded by the National Institutes of Health and the Department of Homeland Security, and also included Donald's graduate student Igor Paprotny and Dartmouth College physicist Christopher Levey.

Donald has been working on various versions of the MEMS microrobots since 1992, initially at Cornell and then at Stanford and Dartmouth before coming to Duke. The first versions were arrays of microorganism-mimicking ciliary arms that could "move objects such as microchips on top of them in the same way that a singer in a rock band will crowd surf," he said. "We made 15,000 silicon cilia in a square inch."

A February 2006 report in the Journal of Microelectromechanical Systems by Donald, Paprotny, Levey and others detailed the basics of the current design: devices about 60 microns wide, 250 microns long and 10 microns high that each run off power scavenged from an electrified surface.

Propelling themselves across such surfaces in an inchworm-like fashion impelled by a "scratch-drive" motion actuator, the microrobots advance in steps only 10 to 20 billionths of a meter each, but repeated as often as 20,000 times a second.

The microrobots can be so small because they are not encumbered by leash-like tethers attached to an external control system. Built with microchip fabrication techniques, they are each designed to respond differently to the same single "global control signal" as voltages charge and discharge on their working parts.

This global control is akin to ways proteins in cells respond to chemical signals, said Donald, who also uses computer algorithms to study processes in biochemistry and biology.

In their new reports, the team shows that five of the microrobots can be made to advance, turn and circle together in pre-planned ways when each is built with slightly different dimensions and stiffness.

Following a choreography mapped out with the aid of mathematics, the microdevices ultimately assemble into group micro-huddles that could set the stage for something more elaborate.

"Initially, we wanted to build something like a car that could drive around at the microscopic scale," Donald said. "Now what we've been able to do is create the first microscopic traffic jam."

He said it took him and various colleagues from 1997 to 2002 to create a microrobot that can operate without a tether, three more years to make the devices steer under global control, and another three to independently maneuver more than one at a time.

"The hard thing was designing how multiple microrobots can all work independently, even while they receive the same power and control," he said.

The study's author, Vanessa Gail Perry, Assistant Professor at the George Washington University School of Business, concludes that "Overestimating credit ratings is partly a function of a lack of financial sophistication. In addition, it appears that people who have overestimated their credit rating take less care in managing their finances.”

Professor Perry analyzed data from the Freddie Mac Consumer Credit Survey. The survey collected data on attitudes, behaviors, knowledge and experiences with credit and financial management from around 23,000 people. Results indicate that approximately 32 percent of respondents overestimated their credit ratings, while only four percent underestimated their credit ratings. The findings support previous studies in judgment and decision-making that show that individuals are more likely to be overconfident about their knowledge or abilities.

Those who overestimated their credit ratings had lower incomes, less formal education, and were less likely to own their homes. They were also more likely to be African-American, Hispanic, or female. One possible explanation for these results is that minority consumers in general have less experience with financial markets which in turn affects their tendency to overestimate their credit rating.

Psychologists now believe there is some truth to this argument. Rather than picking our friends based on intentional choice and common values and interests, our friendships may be based on more superficial factors like proximity (think neighbors) or group assignments (your department at work).

Mitja Back, Stefan Schmukle, and Boris Egloff of the University of Leipzig sought to test the notion that random proximity and random group assignment at zero acquaintance would foster friendship in the long run. The researchers investigated 54 college freshmen upon encountering one another for the first time at the beginning of a one-off introductory session and randomly assigned them a seat number in a group of chairs organized in rows.

As reported in a recent issue of Psychological Science, a journal of the Association for Psychological Science, sitting in neighboring seats as a result of randomly assigned seat numbers when meeting for the first time led to higher ratings of friendship intensity one year later. The same was true even if participants were merely in the same row.

The counterintuitive finding suggests that friendships may not be as deliberate we think. “In a nutshell,” write the authors, “people may become friends simply because they drew the right random number.”

Fine wrinkles, deeper creases, saggy areas around the mouth and neck – the sights in the mirror that make baby boomers wince – are not inevitable. They result from a structural breakdown inside the skin that some existing treatments effectively counteract by stimulating the growth of new, youthful collagen, University of Michigan scientists say.

The researchers report an emerging picture of collagen collapse and possible renewal, based on more than a decade of studies, in the May issue of Archives of Dermatology.

The article draws on dozens of studies since the early 1990s, conducted primarily by U-M dermatologists, to explain why three types of available skin treatments are effective: topical retinoic acid, carbon dioxide laser resurfacing and injections of cross-linked hyaluronic acid.

These treatments all improve the skin’s appearance – and its ability to resist bruises and tears – by stimulating new collagen. Collagen is a key supporting substance, plentiful in young skin, that’s produced in the sub-surface layer of skin known as the dermis. The U-M findings show that the breakdown of the dermis’ firm, youthful structure is a very important factor in skin aging – a much more straightforward thing to fix than genetic factors that others theorize may be involved.

“Fibroblasts are not genetically shot,” says John J. Voorhees, M.D., F.R.C.P., chair of the Department of Dermatology at the U-M Medical School and the article’s senior author. Fibroblast cells in the skin are the key producers of collagen.

“We have shown that if you make more collagen go in, it provides an environment in which fibroblasts recover and make more collagen.”

Voorhees and co-authors Gary J. Fisher, Ph.D., U-M professor of dermatology, and James Varani, Ph.D., U-M professor of microbiology and immunology and pathology, hope the findings will help people make intelligent decisions amid the hype of the multi-billion-dollar anti-aging products industry. Fisher directs the U-M Photoaging and Aging Research Program.

“We want to educate clinicians about what’s been found, and what it means in terms of how we may improve the appearance of people,” says Voorhees, the Duncan and Ella Poth Distinguished Professor of Dermatology at U-M.

Young vs. old skin

Collagen formation and breakdown takes place in the dermis or inner skin, the thicker, firm layer of skin that lies beneath the paper-thin outer skin or epidermis, much as a mattress lies beneath a sheet. Collagen consists of proteins that make up a supporting structure surrounding the skin cells. In youthful skin, collagen is firm, taut and abundant, like a new mattress. In older skin, the collagen structure begins to fall away, says Voorhees.

Just as a foam mattress over time becomes flatter in places and creased as its structure breaks down, aging skin begins to sag and wrinkle when its collagen is diminished and fragmented. The cycle of events involved in collagen loss is complicated.

As skin ages, reactive oxygen species, associated with many aspects of aging, lead to increased production of the enzyme collagenase, which breaks down collagen. Then fibroblasts, the critical players in firm, healthy skin, lose their normal stretched state. They collapse, and then more breakdown enzymes are produced. People in their 80s have four times more broken collagen than people in their 20s.

“What it’s doing is dissolving your skin,” Voorhees says. “What you’ve got is a vicious cycle. You have to interrupt it, or aging skin is just going downhill.”

In the elderly, in whom the dermis has lost two-thirds or more of its youthful thickness through collagen loss, skin tears and bruises easily. Collagen-building interventions thus have potential for reducing basic health problems such as bed sores, in addition to improving appearance.

A growing body of evidence

The U-M researchers base their conclusions on past studies in which they have explored why certain anti-aging treatments are effective. A 2007 study looked at Restylane, marketed as a dermal filler, and found that injections of the product caused fibroblasts to stretch, promoting new collagen, and also limited the breakdown of collagen.

In another 2007 study, the U-M team tested lotions containing retinol, a form of Vitamin A found in many skin-care products, and found it significantly reduced wrinkles and skin roughness in elderly skin by promoting new collagen. Other U-M studies have shown why some laser treatments work and some less powerful ones do not. Carbon dioxide laser resurfacing is effective because it removes the aging dermis; in the three-week regrowth process, new, young collagen is produced.

Voorhees and his colleagues say they provide needed, independent research on the effectiveness of available and future treatments to counteract skin aging. They have no ties to the manufacturers of products they study.

Seafloor bacteria on ocean-bottom rocks are more abundant and diverse than previously thought, appearing to "feed" on the planet's oceanic crust, according to results of a study reported in this week's issue of the journal Nature.

The findings pose intriguing questions about ocean chemistry and the co-evolution of Earth and life.

Once considered a barren plain dotted with hydrothermal vents, the seafloor's rocky regions appear to be teeming with microbial life, say scientists from the Woods Hole Oceanographic Institution (WHOI) in Woods Hole, Mass., University of Southern California (USC) in Los Angeles, and other institutions.

While seafloor microbes have been detected before, this is the first time they have been quantified. Using genetic analyses, Cara Santelli of WHOI, Katrina Edwards of USC, and colleagues found three to four times more bacteria living on exposed rock than in the waters above.

"Initial research predicted that life could in fact exist in such a cold, dark, rocky environment," said Santelli. "But we really didn't expect to find it thriving at the levels we observed."

Surprised by this diversity, the scientists tested more than one site and arrived at consistent results, making it likely, according to Santelli and Edwards, that rich microbial life extends across the ocean floor.

"This may represent the largest surface area on Earth for microbes to colonize," said Edwards.

"These scientists used modern molecular methods to quantify the microbial biomass and estimate the diversity of microbes in deep-sea environments," said David Garrison, director of the National Science Foundation (NSF)'s Biological Oceanography Program. NSF's Ridge 2000 program funded the research. "We now know that this remote region is teeming with microbes, more so than anyone had guessed."

Santelli and Edwards also found that the higher microbial diversity on ocean-bottom rocks compared favorably with other life-rich places in the oceans, such as hydrothermal vents.

These findings raise the question of where these bacteria find their energy, Santelli said.

"We scratched our heads about what was supporting this high level of growth," Edwards said.

With evidence that the oceanic crust supports more bacteria than overlying water, the scientists hypothesized that reactions with the rocks themselves might offer fuel for life.

In the lab, they calculated how much biomass could be supported by chemical reactions with the rocky basalt. They then compared this figure to the actual biomass measured. "It was completely consistent," Edwards said.

This discovery lends support to the idea that bacteria survive on energy from Earth's crust, a process that could add to our knowledge about the deep-sea carbon cycle and the evolution of life.

Many scientists believe that shallow water, not deep water, is better suited for cradling the planet's first life forms. Up until now, dark, carbon-poor ocean depths appeared to offer little energy, and rich environments like hydrothermal vents were thought to be relatively sparse.

But the newfound abundance of seafloor microbes makes it possible that early life thrived--and perhaps began--on the seafloor.

"If we can really nail down what's going on, there are significant implications," Edwards said. "I hope that people turn their heads and notice: there's life down there."

Until recently, the animal - a shrimplike, energy-dense creature called Diporeia - was a major food source for commercially important species like lake whitefish and many prey fish upon which salmon, trout and walleye rely.

Scientists are employing new research methods in a quest to explain their population freefall, which threatens to negatively affect the Lakes' ecosystems and $4 billion sport fishing industry, said Purdue University researcher Marisol Sepúlveda.

"We want to narrow down likely causes for this decline," said Sepúlveda, an assistant professor of forestry and natural resources. "It may help us halt the animal's further disappearance."

Sepúlveda has begun to identify substances involved in Diporeia metabolism, the set of chemical reactions that maintain life and allow organisms to respond to stress. Differences in levels of these metabolites between individuals and populations in various regions of the lakes may point toward the stressor or stressors responsible for their decline, she said.

In the same biological class as krill and shrimp, these rice grain-sized crustaceans dwell on lake bottoms and feed on descending algal plankton. Their bodies contain 30 percent to 40 percent lipids like fats and oils, making them a vital energy and nutrient source for the entire food web.

They are already gone from many large areas of lakes Michigan, Huron, Erie and Ontario, said collaborating researcher Tom Nalepa. In Lake Michigan, there are almost no Diporeia found at depths shallower than 90 meters. Just 15 years ago, their density often exceeded 10,000 animals per square meter at such depths, said Nalepa, a research biologist with the Great Lakes Environmental Research Laboratory.

The spread of invasive zebra and quagga mussels - voracious filter feeders with an overlapping diet - largely coincides with Diporeia's decline and is widely believed to be at least partially responsible. But research cannot yet explain the link, Nalepa said.

"We don't know why Diporeia are responding so negatively to the mussels," he said.

Sepúlveda is looking into another possible contributor to Diporeia's decline: water pollutants like pesticides, polychlorinated biphenyls (PCBs), flame retardants or others.

Detailed in a study to be published in print and online next month in the journal Aquatic Toxicology, Sepúlveda measured Diporeia's response to a common pollutant and also began to identify differences between declining populations in Lake Michigan and those native to Lake Superior, the only Great Lake where populations remain stable. The latter comparison found the groups shared only 5 percent of their total metabolites, suggesting that animals from the two lakes are biologically quite different, Sepúlveda said.

"The answer to Diporeia decline may be found in these variations," she said.

Sepúlveda and University of Michigan researcher Tomas Hook were awarded a four-year, $560,000 grant by the Great Lakes Fishery Trust in January of this year to further investigate possible causes for Diporeia's decline. Both researchers are co-principal investigators of the project.

"We are casting a wide net to basically address a number of hypotheses at the same time," said Hook, a fisheries ecologist hired by Purdue who will begin work there this July.

In Sepúlveda's study, she and her team contrasted levels of metabolites between a group of control animals and that of an atrazine-exposed population of laboratory-reared Diporeia. They found that animals subjected to atrazine, a commonly used pesticide present in minute levels in Lake Michigan, significantly increased or decreased bodily production of five identifiable chemicals. These included an insect pheromone, a fatty acid, an amino acid and a hydrocarbon, she said.

"We are just beginning to interpret these data, but they give us a better idea of how pollutants affect them," Sepúlveda said. "If nothing else, our results suggest that seemingly insignificant levels of pollution could significantly harm animals like Diporeia."

The project should help address suggestions by some researchers that Diporeia and/or invasive zebra and quagga mussels may be capable of bioaccumulating or affecting levels of pollutants in a way that might intensify their harmful effects, Sepúlveda said.

The project also should deepen understanding of exactly how the invasive mussels hurt Diporeia, Hook said. Researchers have looked into, but have yet to determine, the extent to which the mussels outcompete the crustaceans for food, contaminate their surroundings with their effusive waste material, or influence the transmission and spread of diseases.

Regardless of the reason, Diporeia's decline has already had some measurable negative effects on various fish species. Alewives, an important prey fish that provides Chinook salmon well over 80 percent of its food, have declined in growth rates, condition - measured as the ratio of weight to length - and caloric density since Diporeia populations began declining, said Charles Madenjian, research fishery biologist with the United States Geologic Survey.

"Alewives used to regularly reach 10 inches in length," Madenjian said. "Now we're lucky to find one that breaks 8 inches."

Diporeia previously supplied 50 percent of the food source for the commercially important lake whitefish and now supply only about 5 percent. Since the crustacean's decline began in the 1990s, growth rates and the condition of lake whitefish have substantially fallen off, Madenjian said.

If Diporeia's decline proves to have similar negative consequences upon other species and continues to worsen, the most severe effects may be forthcoming, although it is difficult to predict such outcomes with any certainty, Nalepa said.

Hook said he believes the initial step in taking action is to pinpoint causes.

"The first thing we can do is find out more precisely why they are declining," he said. "If we guess, any management decision we make could be counterproductive."

Zebra and quagga mussels were almost certainly spread to the Great Lakes from Europe or East Asia in the fresh water ballasts of oceangoing vessels, beginning in the late 1980s, Nalepa said. People need to be aware of the risks of spreading harmful invasive species and such ballasts should be more tightly regulated or possibly banned, he said. In one simple preventive measure, boats exchange their freshwater ballast for salt water ballast in the open ocean, thereby killing any freshwater species present.

The study by Sepúlveda used a process called gas chromatography to separate metabolites and matched them with known chemicals on a national database. Researchers identified 76 metabolites among lake-dwelling animals and 302 among the control and atrazine laboratory populations. Results from the two comparative analyses suggest that fatty acids and hydrocarbons are important to the animal's survival or may be interfered with by particular stressors.

Diporeia put on much of their weight during the spring bloom of diatoms, algal plankton they feed upon, during which energy capture and storage are particularly paramount. This leaves them vulnerable to disruptions in food or their ability to store it, a process in which fatty acids play a key role, Sepúlveda said.

Scientists have long argued about whether or not the Earth has some special characteristics that led to the evolution of life. PhD researcher Jose Robles and Dr Charley Lineweaver from the Planetary Science Institute at ANU contend that this is a difficult question to answer because we don’t have information about other Earth-like planets.

“Yet the question ‘How special is the Sun?’ is easier to address because we do have observations of thousands of other Sun-like stars,” explains Dr Lineweaver.

Rather than guess what properties a star should have to enable life, the researchers decided to compare the Sun – which already hosts a life bearing planet – to other stars.

“Our research goes further than previous work which only looked at single properties such as mass or iron content,” says Robles, who is the lead author on the research paper. “We looked at 11 properties that could plausibly be connected with life and did an analysis of these properties: The upshot is that there doesn’t seem to be anything special about the Sun. It seems to be a random star that was blindly pulled out of the bag of all stars.”

The researchers found that the Sun’s mass is the most anomalous of its properties; the Sun is more massive than 95 per cent of stars. The Sun’s orbit around the centre of the galaxy is also more circular than the orbits of 93 per cent of its peers. “But when analysing the 11 properties together, the Sun shows up as a star selected at random, rather than one selected for some life-enhancing property,” Robles says.

The research is part of the ongoing scientific understanding of our place in the universe. “Those who are searching for justification for their beliefs that terrestrial life and humanity in particular are special, will probably interpret this result as a humiliating dethronement,” says Dr Lineweaver. “Those who believe we are the scum of the universe, may find our non-special status uplifting.”

University of Alberta Educational Psychology PhD student Lindsey Leenaars has completed a study that assessed what types of high school students are being indirectly victimized. This includes being involved in emotionally damaging scenarios such as receiving hurtful anonymous notes, being socially excluded, or having rumours spread about them, including threats of physical harm.

Leenaars analyzed data that was collected in Ontario in 2003. More than 2,300 students aged 12–18 filled out an anonymous questionnaire asking them questions, including how they rate their attractiveness, their sexual activity, their friendships and school social problems.

Leenaars found the females who viewed themselves as attractive had a 35 per cent increased chance of being indirectly victimized. Conversely, for males who perceived themselves as good looking, their risk of being bullied decreased by 25 per cent. Leenaars also found older teens (aged 16–18) were at a 35 per cent increased risk of being victimized if they were sexually active.

Leenaars says this information could be used to raise awareness amongst parents, teachers and counselors. She adds it would also be helpful when schools are working on a variety of anti-bullying programs to include all students, not just those who may be traditionally perceived as victims.

“The findings have important implications for the development of interventions designed to reduce peer victimization, in that victims of indirect aggression may represent a broad group.”

Studies reveal that in the dog-eat-dog, look-out-for-No. 1, highly competitive business world, only the aggressive, risk-taking alpha male can expect to succeed as an entrepreneur. That statement may sound sexist, but it represents a commonly held gender stereotype. A team led by a University of Missouri researcher found that these stereotypes influence whether or not men and women decide to pursue entrepreneurship as a viable career option.

“Perception may limit both men and women in the decision to become entrepreneurs,” said Daniel Turban, professor and chair of the Department of Management in the Robert J. Trulaske, Sr. College of Business. “One sex is not inherently more qualified than the other; unfortunately, the underlying societal stereotypes associating entrepreneurship with masculine characteristics may influence people’s intentions to pursue entrepreneurial careers. An interesting result of our study is that both men and women reported similar intentions when entrepreneurship was presented as gender neutral. This suggests that common gender stereotypes can be nullified.”

Although entrepreneurship is a masculine-stereotyped domain, Turban said many of the characteristics believed to be important to entrepreneurial success also are traditionally feminine. For example, caring and nurturing, building relationships with others, and humility are typically attributed to females, but also characterize good entrepreneurship.

Turban, along with Vishal Gupta, of Binghamton University and Nachiket Bhawe, of the University of Minnesota, asked undergraduate business students to read mock news articles about entrepreneurship, answer a comprehensive question, and complete a scale about entrepreneurial intentions. In the control article, there was no mention of gender or gender differences in entrepreneurship. In other articles, the masculine and feminine stereotypes were subtly presented or directly emphasized.

“When the masculine stereotype of entrepreneurship was subtly presented, men had higher entrepreneurial intentions than women, and both men and women were similar to the control group. Those results suggest that entrepreneurship is typically stereotyped as a masculine career option,” Turban said. “However, when masculine characteristics were strongly linked with entrepreneurship, a condition people might expect to favor men, we found that women had higher entrepreneurial intention scores while men had lower.”

Turban said one reason for the persistence of gender differences in male-type careers, like entrepreneurship, may be that common masculine stereotypes associated with this role are not openly discussed in society. Men and women are subconsciously influenced by widely held stereotypes. Turban said that if the goal is to attract more women to entrepreneurship, it may be more desirable to describe entrepreneurship as gender neutral.

Researchers at the University of Minnesota’s Bell Museum of Natural History and Pennsylvania’s Villanova University have discovered a new family of gecko, the charismatic large-eyed lizard popularized by car insurance commercials.

Scientists have long been interested in geckos and their evolution because they are key biodiversity indicators and are found on nearly every continent. Researchers are also interested in the gecko because of the animal’s sticky toe pads, which allow them to scale rough and smooth surfaces -- a characteristic that may have human application in medicine, emergency rescue service and military industries.

Graduate students Tony Gamble from the University of Minnesota and Aaron Bauer from Villanova sequenced DNA from 44 species of gecko and used this genetic data to reconstruct the animals’ family tree. The resulting new classification is different from previous classifications, which are based solely on foot structure.

“A classification based solely on foot structure will track selective pressure on the feet and not represent actual evolutionary history,” said Gamble, who believes his discovery will add to a more accurate gecko family tree that, in turn, will allow scientists to better understand how sticky toe pads have evolved.

The researchers have named the new family “Phyllodactylidae,” referring to the leaf-shaped toes of many of the species in this group (phyllo meaning “leaf:” dactyl meaning “toe”). The new family consists of 103 species found in semiarid and tropical regions of North Africa, the Middle East, North and South America and the Caribbean.

There are only four specimens of the Yangtze giant softshell turtle left on Earth—one in the wild and three in captivity. In order to save this species from extinction, conservation partners from the Wildlife Conservation Society (WCS) and the Turtle Survival Alliance (TSA), working in conjunction with partners from two Chinese zoos and the China Zoo Society, recently paired two of them. A still reproductive, more than 80-year-old, female, living in China’s Changsha Zoo has been introduced to the only known male in China, a more than 100-year-old living more than 600 miles away at the Suzhou Zoo.

The Bronx Zoo-based WCS and the Fort Worth Zoo-based TSA coordinated the critically important move; TSA provided much of the funding, animal reproduction and technical expertise while WCS provided veterinary and logistical support and coordination with wildlife partners in China and New York. Other project partners include Ocean Park and Kadoorie Farm and Botanic Garden, both in Hong Kong.

On Monday, May 5, turtle biologists, veterinarians, and zoo staff from partner organizations convened at the Changsha Zoo to collect and transport the female to the Suzhou Zoo where she joined her new mate to potentially save their entire species. The move was coordinated to coincide with the female’s reproductive cycle.

“This is a story of hope for a species truly on the brink,” said Colin Poole, Director of the Wildlife Conservation Society’s Asia Programs. “We are extremely grateful to our conservation partners both in China and here in the U.S. who made this historic move possible. Now that the turtles are together, we are optimistic that they will successfully breed.”

"I hate to call this a desperation move, but it really was. With only one female known worldwide, and given that we have lost three captive specimens over the past two years, what choice did we have" The risks related to moving her were certainly there, but doing nothing was much riskier," said Rick Hudson, TSA co-chair and Fort Worth Zoo conservation biologist.

Listed at the top of the World Conservation Union’s Red List, the Yangtze giant softshell turtle is the most critically endangered turtle in the world. Its status in the wild has long been recognized as grim, but extinction risk now is believed higher than ever. Much of its demise has been attributed to pollution, over-harvesting for Asian food markets and habitat alteration. Biologists saw no other alternative but to save the species by any means necessary. Still, the risks were high—relocating an animal this age can be highly stressful for it and research shows that breeding attempts by males can become aggressive. However, since the female has arrived safely and is settling well into her new habitat at the Suzhou Zoo, biologists are optimistic for breeding success.

The number of humpback whales in the North Pacific Ocean has increased since international and federal protections were enacted in the 1960s and 70s, according to a new study funded primarily by NOAA and conducted by more than 400 whale researchers throughout the Pacific region.

However, some isolated populations of humpbacks, especially those in the Western Pacific Ocean, have not recovered at the same rate and still suffer low numbers.

The new research reveals that the overall population of humpbacks has rebounded to approximately 18,000 to 20,000 animals. The population of humpback whales in the North Pacific, at least half of whom migrate between Alaska and Hawaii, numbered less than 1,500 in 1966 when international whaling for this species was banned. In the 1970s, federal laws including the Marine Mammal Protection Act and the Endangered Species Act provided additional protection.

“NOAA is proud to have played a key role in initiating and funding this study,” said retired Navy Vice Adm. Conrad C. Lautenbacher, Ph.D., under secretary of commerce for oceans and atmosphere and NOAA administrator. “It is only through this type of international cooperation that we can gauge our success and measure what additional work needs to be accomplished to protect highly migratory marine mammals.”

The results of this new report come from SPLASH (Structure of Populations, Levels of Abundance and Status of Humpbacks), an international effort involving more than 50 organizations. Launched in 2004, the project determined whale migratory patterns and estimated population sizes by using a library of 18,000 photographs of whale flukes to identify 8,000 individual whales.

Cascadia Research in Olympia, Wash., the central coordinator for the SPLASH project, matched photographs from six different feeding and breeding areas. By matching whale flukes photographed in their feeding areas with those photographed in the wintering areas, researchers were able to determine the patterns of individual whale movements, as well as estimate the sizes of different populations.

In addition to whale fluke photographs, SPLASH researchers collected more than 6,000 biopsy samples for studies of genetics and pollutants, along with thousands of additional photographs to determine how levels of scarring from line entanglement and ship strikes vary among regions. The samples, which are yet to be analyzed, will provide valuable insights into the complex population structure and current threats to further recovery.