Saturday, April 5, 2008

Hibernation Method Tested for Space Travel

To Sleep, Perchance to Hibernate
To Sleep, Perchance to Hibernate

No matter how much you like your crewmates, a three-year mission to Mars would test the even the best of relationships.

And that's not even the primary reason why future long-duration space travelers may spend part of the journey in suspended animation.

There's the tremendous expense of carrying food, oxygen and carbon dioxide scrubbers to keep astronauts alive, not to mention the hassle of processing their urine and feces.

"Wouldn't it be neat if you could just put them out?" said Warren Zapol, the head of anesthesiology at Harvard University's Massachusetts General Hospital.

One option would be to cool the crew cabin into a big chill. But body temperatures below 30 Celsius (86 degrees F) can disturb the heart's rhythm. Another possibility would be to have the astronauts breathe swamp gas.

Zapol and colleagues report in this month's Anesthesiology journal about how hydrogen sulfide -- the same stuff produced by rotten eggs and swamp gas -- slows mouse metabolism without cutting blood flow to the brain.

"The mice aren't asleep," Zapol told Discovery News. "If you pinch their tails, they respond.

"I don't know what it's like," he added, "probably some slow-motion world."

There are many questions and years of research before healthy people like astronauts would be put into hibernated states, but the procedure could find an earlier application in cases of traumatic injury when life itself is at risk.

"Sixty percent of people in war are dead right there on the field," Zapol said. "They are instantly hurt, and because there is no blood and no fluids in the field, by the time they get to a hospital they are cold and dead and there is nothing to fix.

"During this early period after trauma, if we could freeze you down or shut you down, we could restart you after we fix the aorta, or whatever has been damaged," Zapol said.

Emergency medical workers have tried cooling victims, but the amount of cold water needed to reach effective temperatures makes the technique impractical, particularly in battlefield situations.

"Corpsmen aren't walking around with 150 pounds of cold water," Zapol said. "But what if you could just fog them with hydrogen sulfide?"

During Zapol's experiment, metabolic measurements of the mice, such as their consumption of oxygen and production of carbon dioxide, dropped as early as 10 minutes after they began inhaling hydrogen sulfide.

They remained low as long as the gas was administered. The mice returned to normal within 30 minutes after normal air started to flow.

The animals' heart rate dropped nearly 50 percent while they were breathing the gas, with no significant change in blood pressure or the strength of the heart beat. Respiration rates decreased, but there were no changes in blood oxygen levels, suggesting that vital organs were not at risk of oxygen starvation, the researchers report.

Zapol plans additional experiments on larger mammals, probably sheep.

"Before you use it on astronauts, you want to make sure it's very, very safe," he said.

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Stereotyping Yourself Contributes toYour Success(or Failure)

You tried so hard. But you failed. You did not pass the test, you performed poorly in the interview or you missed your project goal at the office. Why? Is it that you were not capable? Or could something more subtle—and worrisome—also be at work?

As it turns out, research shows that such performance failures cannot always be attributed simply to inherent lack of ability or incompetence. Although some have jumped to the highly controversial conclusion that differences in attainment reflect natural differences between groups, the roots of many handicaps actually lie in the stereotypes, or preconceptions, that others hold about the groups to which we belong. For instance, a woman who knows that women as a group are believed to do worse than men in math will, indeed, tend to perform less well on math tests as a result.

The same is true for any member of a group who is aware that his or her group is considered to be inferior to others in a given domain of performance—whether it is one that appears to tap intellectual and academic ability or one that is designed to establish athletic and sporting prowess. Just as women’s performance on spatial and mathematical tasks is created by, and appears to “prove,” the stereotype of their spatial and mathematical inferiority, so, too, the sporting performance of a team of long-failing underdogs will tend to live up (or, in fact, down) to its low expectations.

The social psychological research that has uncovered these effects is an important development of theoretical work initiated in the 1970s that focused on issues of social identity—looking at how people see themselves as members of a particular group and what the implications of this are. More important, however, social identity research examines not only how we both take on (internalize) and live out (externalize) identities that are shared with our peers—other members of our in-group—but also how these things can change. This research helps us to understand the debilitating consequences of sexism, racism, homophobia and the like, as well as to identify ways of addressing the problems they cause so that human talent and potential are not neglected or squandered.

Part of the story here involves ­recognizing not only that stereotypes can promote failure but that they can also lift a person’s or group’s performance and be tools that promote social progress. Understanding these ­dynamics—and the processes that ­underpin them—enables us to think more productively about the conditions that allow ability to be expressed rather than repressed and that foster success rather than failure.

Stereotype Threat
In the past decade such issues have been put on center stage by social psychologists who have been researching the phenomenon of “stereotype threat.” The impressive body of work they have built up demonstrates not only that such underperformance occurs but also that it is especially common for individuals who are aware that their group is considered inferior to others with which it is compared. Pioneering studies conducted at Stanford University by Claude Steele and Joshua Aronson are particularly illuminating in this respect.

Steele and Aronson’s classic demonstration of stereotype threat emerged from a series of studies in the mid-1990s in which high-achieving African-American students at Stanford completed questions from the verbal Graduate Record Examinations (GRE) under conditions where they thought either that the test was measuring intelligence or that it was not a test of ability at all. Intriguingly, these participants’ performance was much worse when they were told that the test was a measure of intelligence. This slide, the researchers argued, occurred because “in situations where the stereotype is applicable, one is at risk of confirming it as a self-characterization, both to one’s self and to others who know the stereotype.”

This pattern of findings has been replicated with many different groups on many different dimensions of stereotype content. For example, Sian L. Beilock of the University of Chicago and her colleagues reported in a 2007 issue of the Journal of Experimental Psychology that if female students are made aware of the stereotype that men have greater mathematical ability than women do, they tend to perform worse on complex mathematical tasks than they do if they are not alerted to this stereotype. Likewise, elderly people have been found to perform worse on memory tests if they take them after being made aware of stereotypes that associate aging with deteriorating cognitive ability.

In the domain of athletic performance, studies of golf putting have shown that expert golfers tend to leave their putts farther from a target than they would otherwise do if they are exposed to a stereotype that members of their sex are worse at putting than members of the opposite sex. It seems unlikely that Greg Norman choked in the 1996 Masters Tournament, when he blew an early lead and ultimately lost, because he was mindful of this stereotype, but other relevant stereotypes (for instance, that Australians underperform in the Masters—with no one from that country ever having won the tournament) may have interfered with the flow of his game at the critical juncture. Along similar lines, it seems entirely plausible that England’s poor performance on penalty shoot-outs in World Cup soccer matches has something to do with a lack of self-belief associated with a team history of performing poorly in such contests (of seven shoot-outs in major tournaments, the team has won only one).

Understanding Process
What, though, is the “something” that is responsible for the effects of stereotype threat? Recent work has argued that one core factor is enhanced cognitive load. For example, a 2005 study by social psychologists Mara Cadinu, Anne Maass and colleagues at the University of Padua in Italy showed that when women perform mathematical tasks after being exposed to the stereotype that they are worse at math than men, they report entertaining more intrusive negative thoughts about their own mathematical ability. That is, they find themselves thinking things such as “These exercises are too difficult for me” and “I am not good at math.” Likewise, a number of studies have indicated that exposing people to negative stereotypes about groups to which they belong increases their anxiety and stress when performing tasks related to that stereotype.

Evidence from work by Beilock and others also suggests that such anxieties can use up information-processing resources that are required to carry out the tasks at hand. For example, when people perform complex math tasks, this cognitive burden places heavy demands on working memory, using the brain areas that briefly store and manipulate information.

The 2007 article by Beilock and her colleagues attempts to explore and integrate these ideas by delving deeply into the cognitive dynamics of stereotype threat. Working in the domain of women’s performance on mathematical tasks, a series of experiments replicates the standard stereotype threat effect: it shows that the effect is most pronounced on tasks that place demands on phonological resources (such as those requiring verbal reasoning); demonstrates that the presence of stereotype threat increases verbal reports of worry associated with either the task or the stereotype; and suggests that the debilitating consequences of stereotype threat can be avoided if participants learn to perform tasks in such a way that they are mentally undemanding. The last insight is based on evidence that women do not succumb to the effects of stereotype threat if they learn answers to math problems by rote (as one does when learning one’s times tables) so that their production relies only on long-term memory.

On the basis of these studies, the researchers make the case that their work advances our understanding of stereotype threat by revealing what is responsible for its effects (for instance, anxiety-related demands on short-term verbal memory) and then using this understanding to suggest how this impact can be overcome. In this regard, there is no doubt that their work contributes substantially to our understanding of specific cognitive aspects of the phenomenon, and in particular the role that memory processes can play in the dynamics of particular threat-related effects. Yet despite its internal coherence, there are reasons for believing that an exclusively cognitive analysis is limited both theoretically and practically.

Stereotypes That Help
A sense that the theoretical analysis by Beilock and her colleagues is incomplete derives from other research inspired by Steele and Aronson’s original demonstration of the effects of stereotype threat. Exposure to stereotypes, researchers have found, can have welcome as well as unwelcome consequences. That is, under certain circumstances, exposure to stereotypes about one’s group can serve to elevate performance instead of compromising it.

Studies conducted at Harvard University in 1999 by Margaret Shih and her co-investigators provide particularly good demonstrations of this point. The participants in this research were Asian women. In different conditions of the studies they were required to focus on the fact either that they were women (who are stereotypically worse at math than men) or that they were Asian (stereotypically better at math than members of other ethnic groups). As in Beilock and her colleagues’ work, in the former case the women performed worse than they did when no group membership was made salient. Yet in the latter case they did better.

Other studies reveal similar effects, finding that women display superior ability on spatial tests if reminded that they attend a college whose students perform well on such tasks and that golfers putt more accurately if exposed to a stereotype that members of their sex are better at putting than those of the opposite sex. Jeff Stone of the University of Arizona and fellow psychologists also found that when white golfers are told that their golfing performance will be compared with that of black golfers they perform worse if they believe this is a test of “natural athletic ability” (because here the comparison poses a threat), but that they perform better if they believe it to be a test of “sport strategic intelligence” (because this comparison suggests the in-group’s superiority).

A meta-analysis of similar studies published in 2003 by social psychologists Gregory Walton and Geoffrey Cohen, then at Yale University, has shown that if people are exposed to stereotypes about the inferiority of an out-group (those who are not part of the individual’s in-group) in a given domain, then their performance is typically elevated—a phenomenon they refer to as stereotype lift. In this way, just as a sense of in-group inferiority can impair performance, an ideology of superiority can give members of high-status groups a performance boost.

Such elevated performance cannot easily be explained in terms of cognitive load—because it is hard to see how the salience of a positive in-group stereotype (as in “we are good”) could increase the memory resources available to participants (relative to those in control conditions). Ideally, then, a parsimonious explanation of the effects of stereotypes should be capable of accounting for both upward and downward change. It should also be able to explain a host of other effects reported in the research literature—including evidence that such effects are apparent in domains where cognitive capacity is not critical (golf or basketball, say); are diminished if people are exposed to stereotypes about multiple groups; are weaker if one’s in-group is not exposed to generalized hostility (for example, if one is male or white); and vary depending on whether participants are encouraged to focus on promoting positive outcomes or on preventing negative ones.

More important, an explanation of effects arising from stereotype threat also needs to explain why these influences are not as generalized as a cursory reading of Beilock and her colleagues’ work might suggest. Because it is certainly not the case that all members of a given group succumb to the perils of threat.

On the contrary, effects are restricted to individuals who value the domain in question and who have high levels of basic competence (for instance, those who, in the abstract, have less to worry about). To be selected to participate in Beilock and her colleagues’ first study of mathematical performance, for example, women had to perform baseline tasks with greater than 75 percent accuracy, and they had to agree with the statements “I am good at math” and “It is important to me that I am good at math.” Why do these things matter?

Self and Identity
One answer to the preceding question is that, fundamentally, stereotype threat is not so much an issue of cognition per se as one of self and identity. This point has been made by a number of researchers working in the stereotype domain, including Steele and Aronson themselves. Along these lines, in a recent major review of work in this area, they, together with social psychologist Steven Spencer of the University of Waterloo in Ontario, argue that stereotype threat can be understood as a phenomenon that centers on a person’s social identity. That is, stereotype threat (and lift) effects come about because, and to the extent that, people are encouraged to think of themselves in terms of a particular group membership (such as Asian or female; white or male).

As specified by the social identity theory that Henri Tajfel and John Turner developed at the University of Bristol in England, when people define themselves as group members (as “we” rather than “I”), behavior is shaped by the stereotypic norms that define in-group membership in any given context [see “The Psychology of Tyranny,” by S. Alexander Haslam and Stephen D. Reicher; Scientific American Mind, Vol. 16, No. 3; 2005]. Here people are generally motivated to advance the interests of their in-group and to see it positively. They are, for example, more inclined to agree with stereotypes that suggest “we are good” than with those that say “we are bad.” Yet under conditions in which broad consensus exists about an in-group’s low status and in which status appears to be stable and legitimate (that is, uncontestable), members of that group often accept and internalize their group’s inferiority on status-defining dimensions (“We are poor at math …”) and seek to achieve a positive in-group identity in other areas (“… but we are more verbally skilled, more sociable, more musical, and so on”).

Thus, when the content of a salient social identity conflicts with a person’s motivations to do well in a given domain (to be good at math, for instance), he or she will experience identity-related psychological conflict. This conflict tends to interfere with performance in the way that studies of stereotype threat reveal. As the work of Cadinu and others shows, it creates anxiety, self-consciousness and self-doubt. In short, people will tend to perform relatively poorly in situations where they have a conflicted sense of self—wherein their sense of what they are (and want to be) as individuals appears incompatible with what they are seen to be as group members.

On the other hand, if the content of a salient social identity is compatible with a person’s aspirations (perhaps because they suggest superior ability), this circumstance will tend to motivate and energize the individual and thereby improve performance in the manner suggested by demonstrations of stereotype lift. We experience a facility of self and “flow” when what we are and want to be as individuals is fully compatible with what we appear to be as group members.

Overcoming Stereotypes
One final question, though, is whether the phenomenon of stereotype threat (or lift) means that people are destined always to reproduce existing stereotypes and social structures. Are we inevitably condemned to act in ways that reinforce existing stereotypes of superiority and inferiority? Not at all. Indeed, one important lesson to be learned from theorizing about social identity is that when individuals are confronted with obstacles to self-enhancement associated with the apparent inferiority of their in-group, they can deal with these obstacles in multiple ways. These strategic responses do more or less to reproduce the status quo.

The first is to adopt a strategy of “social mobility,” which involves individual-level activities that serve to downplay the impact of the group on the self. In effect, this is the kind of strategy that Beilock and her colleagues recommend when they encourage participants to work hard to learn solutions to problems by rote so they will no longer be handicapped by stereotype threat. The limitation of this solution is that it protects the individual by working around the problem but, in the process, leaves the problem itself unresolved. As two of us (Haslam and Reicher) note in a 2006 article in the Journal of Applied Psychology, such activities thus involve attempting to cope with the stress of threats to self through a strategy of personal avoidance. This approach may be cognitively sophisticated but politically naive.

A second strategy is one of “social creativity,” which invokes different in-group stereotypes that deflect the impact of belonging to a disadvantaged group. Traditionally, researchers and laypeople alike have tended to think of stereotypes as fixed and invariant representations of social groups that are impervious to change. In fact, however, the large body of evidence reviewed in the mid-1990s by Penelope Oakes and her fellow social identity researchers at the Australian National University suggests that stereotypes—of both ourselves and others—are inherently flexible.

For example, the degree to which psychology students think of themselves as “scientific” or “artistic” has been shown to vary considerably depending on whether they compare themselves with drama students or with physical scientists. In comparison with physical scientists they are more inclined to stereotype themselves as artistic, but in comparison with people who work in the theater they are more inclined to stereotype themselves as scientific. Psychology students should experience stereotype threat if they are asked to perform a scientific task when compared with physicists or an artistic task when compared with artists, but they should experience stereotype lift if asked to perform an artistic task when compared with physicists or a scientific task when compared with artists.

Leaders and other agents of change are thus able to promote changes to in-group stereotypes by altering the dimensions of comparison, the comparative frame of reference or the meaning of particular attributes. There is a sense, however, in which these strategies of social creativity still work within a prevailing consensus rather than doing anything directly to change features of the social world that give rise to a group’s stigmatization and disadvantage. In this respect, they can still be seen as strategies of threat denial rather than threat removal.

A third alternative, then, is to advocate group-based opposition to the status quo through a strategy of social competition that involves engaging in active resistance. Here group members work together to challenge the legitimacy of the conditions (and associated stereotypes) that define them as inferior—trying to change the world that oppresses them rather than their reactions to the existing world. They work to counter the stereotypes that are tools of their repression with stereotypes that are tools of emancipation. This strategy was precisely what activists such as Steve Biko and Emmeline Pankhurst achieved through black consciousness and feminism, respectively. They challenged the legitimacy of those comparisons and stereotypes that defined their groups as inferior and replaced them with expressions of group pride. They were (as one supporter said of Pankhurst) “self-dedicated reshaper[s]of the world.” And the more their opponents invoked stereotypes against them, the more they acted collectively to contradict those stereotypes and reveal their claims to legitimacy as a lie.

To quote from the evidence that Biko gave at his trial in South Africa in 1976: “The basic tenet of black consciousness is that the black man must reject all value systems that seek to make him a foreigner in the country of his birth and reduce his basic human dignity.”

Which of these three strategies individuals choose to pursue, social identity theory argues, depends on a range of factors that are structural and political as well as cognitive and psychological. In particular, whether or not people seek to change an unequal world rather than adapting to it depends partly on whether they are exposed to social-change belief systems that engage their imagination and articulate cognitive alternatives to the prevailing orthodoxy. In this respect, the significance of established methods for measuring differences between groups (for example, in various forms of ability) derives from their capacity to limit the potential for people to conceive of such alternatives by presenting data as objective and uncontestable “fact.” That is, they do not so much measure “real” difference as contribute to making measured differences “real.” In this regard, too, the success of leaders of emancipa­tory movements typically derives from their capacity to create a sense of shared social identity that centers on challenges to the stereotypes and received forms of understanding that define their group as inferior.

Resistance, of course, is not always successful. Yet it is rarely entirely futile either. Indeed, history teaches us that change is as much a part of social reality as is stability. And when they are in our own hands, stereotypes can be essential to mobilizing the group for success as much as, when in the hands of others, they can be used as forces of restraint and ­failure.

Thus, the literature on stereotype threat delivers two fundamental lessons. The first is to beware of equating performance and ability, especially when dealing with differences between groups, and to understand the power that the expectations of others has over what we do. The second is to realize that we are not doomed to be victims of oppressive stereotypes but can learn to use stereotypes as tools of our own liberation. In short, who we think we are determines both how we perform and what we are able to become.

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GE's New Water Heater Could Kill 30 Coal Plants

Y'know what's dumb...until today, Energy Star didn't regulate water heaters at all. They're the most energy-hungry single appliance in the home, and are responsible for about 17% of residential energy use. But because of a lack of consensus on how they should be regulated, and resistance from industry, their efficiency went completely unregulated.

Well, that all changed today. Along with the announcement that the new standards will save Americans hundreds of billions of dollars per year, comes two new water heaters from GE that will, of course, meet the new standards.

The first is available now. It's a tankless heater that provides hot water only when you need it. The result is an unlimited supply of hot water, and about 25% less energy use per gallon of hot water produced.

The second is even more exciting, though, unfortunately, it won't be available until 2009. GE is calling it a "hybrid electric" water heater, I suppose hoping to capitalize on the excitement surrounding hybrid electric vehicles. But it is a kind of hybrid. The water heater first uses a heat pump to bring the water up to the temperature of the ambient air. Then the electric water heater takes over, bringing the water up to 140 degrees F.

This new design is more than 50% more efficient than previous water heaters. If every home in America had one right now, we would need 30 fewer coal-fired power plants! Every home that installs one will see their yearly power bills drop up to $250.

Because the new device uses a heat exchanger, it will actually make your furnace work harder during the winter. But in the summer, and in warm climates, it will actually help cool your house!

This is exactly the kind of technology we need to hold us over until renewables take over for coal. GE's got a video featuring the new devices online if you'd like to check it out.

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Life on Mars: Stunning 3D photos show the Red Planet's mountain ranges for the first time

These stunning pictures reveal for the first time the planet Mars's stunning mountain landscape.

The 3D photographs were taken by a high resolution stereo camera on board the European Space Agency's Mars Express orbiter and beamed 43million miles to Earth.

They show Hebes Chasma, an enclosed trough, almost five miles deep, in the Grand Canyon of the Red Planet.

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A taste of Mars: The pictures show the planet's spectacular mountain range, the Hebes Chasma, with its five-mile deep canyon

Insight: Scientists say they will use the photographs to try and prove that water once existed on the planet, which is 43million miles from Earth

By imaging the landcape at three different wavelengths, the camera gives an insight into how the moutain range would look if you were standing on Mars.

But the photos are not just for show - they have also provided scientists with invaluable data about the planet's surface and may prove that water once existed in the canyon.

In addition, they will enable researchers to make a detailed examination of the altimetry of the Mars's surface, and to calculate the slope of its valleys.

Some observers have also been quick to point out that its rough, brown-coloured terrain bares a close remsemblance to the planet's chocolate namesake, the Mars bar.

Mars attacks: Three photographs - all at different wavelengths - were taken to create an accurate representation of how the canyon looks in 3D

Seeing red: With its distinctive shades of brown, some have likened the canyon to a Mars bar, which they say mirrors the planet's terrain

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Unhappy with your shape? It's your genes

Are you mystified why your sporty friend eats whatever she wants and still fits into a skimpy dress and you, on the other hand, never seem to be the right shape to wear anything fashionable?

Blame your genes.

According to an Anglo Israeli study, a woman's muscle mass may have less to do with exercise and abstaining from sweets than it does with the DNA of her parents.

In the study, which focused on brawn, sinew and shape more than obesity, Prof Gregory Livshits from Tel Aviv University and Prof Tim Spector from King's College in London have found a link between the muscle mass of a woman and her genes.

"We have known that obesity is heritable - but this study shows the importance of genes determining how much muscle each of us has - which determines body shape and also athletic abilities," says Prof Spector.

"Finding the genes responsible will have major impacts on sports as well a s explaining why many people will never obtain the perfect figure." adds Prof Spector who led the research team.

In the study more than 3,000 middle-aged British women who belonged to either an identical or fraternal twin pair were examined. The team from the St Thomas' Twin Unit measured the volunteers' "total lean mass," one of the three major components of total body weight - along with bone - and compared it to markers in their genes.

Until now, scientists were not sure to what extent environmental influences and genetics played a role in muscle mass. When controlling for age, and fat, they found that genes account for over half of the differences in womens' body sizes.

Those without the lean genes, however, will always find it harder to stay slim, predicts Prof Livshits. "The bad news is that many of our physical features, including our weight, are dependent on our genes. The good news is that women still have an opportunity to go against their genetic constitution and do something about it."

The study is published in the Journal of Clinical Endocrinology and Metabolism.

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Horses can count, new study says

Horses can count, according to a new study that suggests they are more intelligent than previously thought.

Researchers found that, when offered a choice, they consistently choose buckets containing higher numbers of apples.

Two horses areseen in a stable: Horses can count, new study says
Horses can differentiate between small quantities

Babies aged from 10-months-old have been shown to have an innate tendency to opt for containers holding larger numbers of food items, as have many non-human primates such as rhesus macaques and lemurs.

Dr Claudia Uller, of the University of Essex, was inspired to investigate whether horses could count by the story of Clever Hans, a horse that caused a sensation 100 years ago with his apparent abilities to simple arithmetic and keep track of the calendar.

In public performances in Germany he is said to have communicated the answers to questions by tapping his foot.

However psychologist Oskar Pfungst carried out an investigation and reported in 1911 that Clever Hans was not performing arithmetic, but had learnt to obtain the required answers by interpreting the reactions of his maths teacher owner and other observers.

Dr Uller, speaking at the British Psychological Society conference in Dublin yesterday said: "Nobody has been able to show any mathematical abilities in horses since then.

"However our results suggest that horses too, and not only primates, are able to spontaneously discriminate between two small numbers.

"It shows horses are more intelligent than we thought. This may be another piece in the jig saw explaining the evolutionary origins of our ability to count."

Dr Uller and colleague Jennifer Lewis carried out a series of experiments involving riding school and privately owned horses stabled near Colchester, Essex.

In one task, 11 of 13 horses consistently selected buckets containing three plastic apples over another containing two when offered a choice. Fake fruit was used to ensure no difference in smell.

Researchers then showed 12 different horses a box holding either two identical small apples or another containing one large apple with double the surface area. Again, all but two selected the greater number of apples.

In a study published in February, Italian researchers found certain species of fish can count up to four.

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Identical Twins' Genes Are Not Identical


NOT-SO-IDENTICAL TWINS: They look the same but their genes may reveal some fundamental differences.

Identical twins are identical, right? After all, they derive from just one fertilized egg, which contains one set of genetic instructions, or genome, formed from combining the chromosomes of mother and father.

But experience shows that identical twins are rarely completely the same. Until recently, any differences between twins had largely been attributed to environmental influences (otherwise known as "nurture"), but a recent study contradicts that belief.

Geneticist Carl Bruder of the University of Alabama at Birmingham, and his colleagues closely compared the genomes of 19 sets of adult identical twins. In some cases, one twin's DNA differed from the other's at various points on their genomes. At these sites of genetic divergence, one bore a different number of copies of the same gene, a genetic state called copy number variants.

Normally people carry two copies of every gene, one inherited from each parent. "There are, however, regions in the genome that deviate from that two-copy rule, and that's where you have copy number variants," Bruder explains. These regions can carry anywhere from zero to over 14 copies of a gene.

Scientists have long used twins to study the roles of nature and nurture in human genetics and how each affects disease, behavior, and conditions, such as obesity. But Bruder's findings suggest a new way to study the genetic and environmental roots of disease.

For example, one twin in Bruder's study was missing some genes on particular chromosomes that indicated a risk of leukemia, which he indeed suffered. The other twin did not.

Bruder therefore believes that the differences in identical twins can be used to identify specific genetic regions that coincide with specific diseases. Next, he plans to examine blood samples from twin pairs in which only one suffers from asthma or psoriasis to see whether he can find gene copy number changes that relate to either of these illnesses.

The result might also call into question the many findings of previous twin studies that assumed identical twins were indeed identical, Bruder notes. "It's pretty unlikely they're going to significantly change any of the results found so far," counters Kerry Jang, a psychologist at the University of British Columbia in Vancouver, who runs Canada's largest twin study. "We can adjust our models to take [genetic differences] into account in the same way we've adjusted for different environments."

The discovery of this genetic variation gives hope for an obscure but pressing issue in the case of a criminal suspect who is an identical twin. "If one twin is a suspect and the whereabouts of the other twin cannot be determined, then the jury is often left without the ability to find guilt beyond a reasonable doubt" in cases that rely on DNA evidence, says Frederick Bieber, a pathologist at Harvard Medical School.

"If the twin issue comes up in a criminal investigation it's possible that if there are [copy number variants] that differ between the two twins that might help sort that out," Bieber says.

Given that there are 80 pairs of identical twins in Virginia's convicted offender database alone, this might not be as small an issue as it may sound. And such genetic variation also matters to the population at large.

Bruder speculates that such variation is a natural occurrence that accumulates with age in everyone. "I believe that the genome that you're born with is not the genome that you die with—at least not for all the cells in your body," he says.

Charles Lee, a geneticist at Brigham and Women’s Hospital in Boston, agrees. Genetic variations can arise after a double strand of DNA breaks when exposed to ionizing radiation or carcinogens. "It reminds us to be careful about our environment because our environment can help to change our genome," he says.

Plus, these variations may predict age-related diseases. Lee adds: "As you age … your chances for having a genomic rearrangement that causes a certain disease increases all the time."

The differences between identical twins increase as they age, because environmentally triggered changes accumulate. But twins can also begin their lives with differences, according to Bruder's study, and that calls into question their very name.

"Maybe we shouldn't call them identical twins," Harvard's Bieber says. "We should call them 'one-egg twins.'"

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Aztec Math Used Hearts and Arrows

Oztoticpac-Lands-Map AZTEC MATH: The Aztec used symbols such as arrows and hearts to denote fractional units of measurement in surveying records like the Oztoticpac Lands Map pictured here.

The Aztecs had more numbers than we do, or at least symbols denoting numerical concepts. When it came to measuring land—critical for levying the proper tax or tribute—these medieval Mesoamericans used arrows, hearts, hands and other units representing fractions, according to a new study in Science.

To figure this out, mathematician Maria del Carmen Jorge y Jorge of the National Autonomous University of Mexico (U.N.A.M) channeled the mind of an Aztec land surveyor. That meant retraining herself to use a different numerical system and combing through the Codex Vergara, one of two remaining books that record Aztec land surveying.

Working with geographer Barbara Williams and del Carmen Jorge y Jorge counted 367 fields in this book with both an overall area for the plot of land as well as the lengths of the sides. Roughly 60 percent of these fields had areas that matched the basic mathematical rule of length multiplied by width or other common surveying calculations.

But the rest were off, usually by a small amount. And 69 had areas that were prime numbers such as 211—numbers that cannot be created by multiplying two whole numbers together, such as 20 times 10. Instead, del Carmen Jorge y Jorge determined that the Aztecs were using the equivalent of fractions.

"We found these smaller units of measure that we call monads that have the role of a fraction," she says. "We don't like to call them fractions, though, because they were considered as unitary entities like inches, seconds or minutes."

To denote half the Aztec basic unit of measure—known by Aztec experts as tlalquahuitl or land rods—the surveyors used an arrow symbol. So for a field that measured 20 land rods by 10 land rods plus an arrow (or 20 multiplied by 10.5), the correct area was 210. "Two arrows is one unit, five hearts is two units, five hands is three units," del Carmen Jorge y Jorge notes.

These extra units—arrow, heart, hand, bone and arm—cannot be subdivided further, standing alone as essentially extra numbers. It is unclear what exactly these measurements equal, but the team speculates that an arrow is the measure of the length from the shoulder to the hand (like an archer with a taut bow), a heart is a measure of the length from that organ to the tip of the hand and a hand as the measure from outstretched hand to outstretched hand—just as an English foot is the measure of a man's foot. "That could be an interpretation," del Carmen Jorge y Jorge says. "We cannot prove it."

The researchers will next try to assess the accuracy of the Aztec surveyors. The neighborhood of Asuncion outside Mexico City still bears the markings of the ancient Aztec terraced fields on its hillsides that were recorded in the Codex Vergara. "We were there trying to measure those terraces," del Carmen Jorge y Jorge says. "This is complicated because this is sloping land."

It is no doubt easier to measure sloping land with modern devices like satellite global positioning systems and computers than it is to try to inhabit an alternative mathematical system and devise the meaning of mysterious symbols—as well as grasp the algorithms that can explain how they were used. "I can use my math, my computers and whatever I want," she says. "With this paper, I am only using hand calculations."

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Boeing makes first ever hydrogen battery flight

OCANA, Spain (AFP) - US aircraft maker Boeing flew a plane that was powered by a hydrogen battery at the start of 2008 for the first time in aviation history, senior company officials said in Spain on Thursday.

"For the first time in the history of aviation, Boeing has flown a manned airplane that was powered by a hydrogen battery," Boeing chief technology officer John Tracy told a news conference at the firm's research centre in the central Spanish town of Ocana.

The plane, which used propellers, flew at a speed of 100 kilometres (62 miles) an hour for about 20 minutes at an altitude of about 1,000 metres (3,300 feet) using only the hydrogen battery for power, Boeing said in a statement.

The director of the Ocana research centre, Francisco Escarti, said the hydrogen battery "could be the main source of energy for a small plane" but would likely not become the "primary soruce of energy for big passenger planes".

"The company will continue to explore their potential as well as that of all durable sources of energy that boost environmental performance," he said.

Tracy said the development was "a historical technological success for Boeing" and was "full of promises for a greener future".

"Boeing recognizes that pollution represents a serious environmental challenge," he added.

Amid rising fuel costs and mounting concerns over climate change, airlines are keen to find ways to cut their energy bills and the pollution which they emit.

Boeing's first new model in over a decade, the Dreamliner, used high-tech composites which reduces its weight and which the company says will make it consume 20 percent less fuel then similar-sized planes already on the market.

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Studies Find Genetic Link to Smoking

WASHINGTON (AP) — Scientists say they have pinpointed a genetic link that makes people more likely to become hooked on tobacco, causing them to smoke more cigarettes, making it harder to quit and leading more often to deadly lung cancer.

The discovery by three separate teams of scientists makes the strongest case so far for the biological underpinnings of the addiction of smoking and sheds light on how genetics and cigarettes join forces to cause cancer, experts said. The findings also lay the groundwork for more tailored treatments to quit smoking.

“This is kind of a double-whammy gene,” said Christopher Amos, a professor of epidemiology at the M. D. Anderson Cancer Center in Houston and author of one of the studies. “It also makes you more likely to be dependent on smoking and less likely to quit smoking.”

A smoker who inherits this genetic variation from both parents has an 80 percent greater chance of lung cancer than a smoker without the variants, the researchers reported. And that same smoker on average lights up two extra cigarettes a day and has a much harder time quitting.

The three studies, financed by governments in the United States and Europe, are being published Thursday in the journals Nature and Nature Genetics.

The scientists surveyed genetic markers in more than 35,000 people in Europe, Canada and the United States, zeroing in on the same set of genetic differences. They are not quite sure if what they found is a set of variations in one gene or in three closely connected genes. But they said the result was the same: These genetic quirks increase the risk of addiction and lung cancer.

The studies’ authors disagreed on whether the set of variants directly increased the risk of lung cancer or did so indirectly by causing more smoking.

The genetic variations, which encode nicotine receptors on cells, could eventually help explain some of the mysteries of chain smoking, nicotine addiction and lung cancer that cannot be chalked up to environmental factors, brain biology and statistics, experts said.

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Moth that can travel at 55mph

Moths that fly high above our heads throughout the night are not at the mercy of the wind but use a sophisticated internal compass which can help them travel up to 400 miles in a single flight, according to a study.

Silver Y moths, by selecting the fastest moving layers of atmosphere, can cruise at speeds of up to 55 mph
Silver Y moths, by selecting the fastest moving layers of atmosphere, can cruise at speeds of up to 55 mph

While it is not clear how the creatures - in this case, the Silver Y moth - actually navigate between sunset and sunrise, researchers from the UK and Germany have found that the insects can judge the best conditions for flight based on direction and windspeed, selecting the fastest moving layers of atmosphere so, with their own speed of 10mph, can cruise at speeds of up to 55 mph.

Dr Jason Chapman, of Rothamsted Research in Harpenden, Hertfordshire, says: "There has been speculation for many years about whether insects that rely on wind for migration can have control over the direction in which they migrate.

"If they didn't have any control then, in many years, the autumn population would get blown in unsuitable directions and die - the so called Pied Piper effect," he says. "Our studies demonstrate that the moths can influence their direction and speed of movement in a number of ways."

The team found that moths only migrate on nights when wind direction is favourable. The most unexpected finding was that moths could compensate when wind direction was off target, suggesting they have a compass.

Dr Chapman a says: "The moths must have a compass mechanism, similar to that of migratory birds.

The cues used by the insects to set the compass are not known. Day flying insects use the sun or landmarks to navigate. Moths do not have good enough eyesight to use stars, he explains, and the moon's movements are too unpredictable, leaving a magnetic sense as the likeliest one they rely on.

The research was carried out using radar and showed that in August an estimated 200 million Silver Y moths migrated southwards over the UK to breeding grounds in the Mediterranean. The data, from 2003, has only just been processed and is published in Current Biology.

He said there are important implications of the work in helping to warn farmers if pests are about to attack crops. "Considering the high pest status of many insect migrants, and the effects of global warming on the frequency of insect migration, the long range movements of such pests will have increasing impacts on global agriculture."

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Pedal powered 'Flintstone car' driver gets his traffic ticket dismissed

Video of the pedal-powered 1986 Buick Regal's maiden voyage (below)

By Dragana Kovacevic

Part four-seater bicycle, part work of art, this makeshift Buick Regal is pushing the boundaries of driving, quite literally.

Montreal artist Michel de Broin made the "Shared Propulsion Car" by hollowing-out the insides.

It has:

  • no engine
  • no transmission
  • no floor
  • no signal lights
  • in place of headlights? The car features tea light-candle headlights
  • the whole thing is entirely propelled by pedal power

    With top speeds reaching no more than 15 km/hr, the vehicle uses traditional bicycle handbrakes.

    The cyclers on the left control the propulsion on the left side, and the same goes for the two cyclers on the right. Should one side break earlier than the other, the car would pivot and turn.


    The "Shared Propulsion Car" was on exhibit at the Mercer Union Centre for Contemporary Art on October 24. The work was supposed to make a statement about consumption. The following day, it made a statement about heck of a lot more:

    Dean Baldwin and three others took the vehicle for an impromptu test-drive and got themselves pulled over and ticketed for operating an unsafe vehicle. (See video above)

    However, without a clear definition of what the vehicle even is or what law applies to its altered state, the charges were dropped.

    To celebrate, Baldwin and group took the car-bicycle hybrid for a drive around Bloor and Dufferin on the streets of Toronto.

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    8 Amazing Technicolor Images of Nuclear Fireballs

    Continuing our nuclear theme this week, I thought it might be interesting to showcase some of the most amazing images of destruction that man and nature have ever devised.

    nuclear explosion
    “Licorne” test in French Polynesia 1970, (France)

    Destruction can often be eerily beautiful. It can also remind us of how fragile our existence is and how we mustn’t take it for granted. Below, in no particular order are some of the most incredible pictures of nuclear explosions.

    nuclear explosion
    Operation Tumbler Snapper US 1952

    nuclear fireball
    Operation Upshot/Knothole US 1953

    nuclear explosion
    Operation Upshot/Knothole US 1953

    nuclear explosion
    Operation Ivy US 1952

    operation buster 1951
    Operation Buster-Jangle 1951 (US)

    Operation Greenhouse 1951 (US)

    operation redwing
    Operation Redwing 1956 (US)

    You can also watch a video here of the detonation of 914-kiloton TN-60 thermonuclear warhead (France, “Licorne” test) at Mururoa Atoll, French Polynesia on July 3, 1970. This corresponds to the first photo. Via Vroom101 on Digg.

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    Global temperatures 'to decrease'

    Villager walks through the snow in Nanjing, China (February 2008)
    La Nina caused some of the coldest temperatures in memory in China

    Global temperatures will drop slightly this year as a result of the cooling effect of the La Nina current in the Pacific, UN meteorologists have said.

    The World Meteorological Organization's secretary-general, Michel Jarraud, told the BBC it was likely that La Nina would continue into the summer.

    This would mean global temperatures have not risen since 1998, prompting some to question climate change theory.

    But experts say we are still clearly in a long-term warming trend - and they forecast a new record high temperature within five years.

    The WMO points out that the decade from 1998 to 2007 was the warmest on record. Since the beginning of the 20th Century, the global average surface temperature has risen by 0.74C.

    While Nasa, the US space agency, cites 2005 as the warmest year, the UK's Hadley Centre lists it as second to 1998.

    Researchers say the uncertainty in the observed value for any particular year is larger than these small temperature differences. What matters, they say, is the long-term upward trend.

    Rises 'stalled'

    La Nina 2008 Forecast (Source: UK Met Office Hadley Centre)
    La Nina translates from the Spanish as "The Child Girl"
    Refers to the extensive cooling of the central and eastern Pacific
    Increased sea temperatures on the western side of the Pacific mean the atmosphere has more energy and frequency of heavy rain and thunderstorms is increased
    Typically lasts for up to 12 months and generally less damaging event than the stronger El Nino

    La Nina and El Nino are two great natural Pacific currents whose effects are so huge they resonate round the world.

    El Nino warms the planet when it happens; La Nina cools it. This year, the Pacific is in the grip of a powerful La Nina.

    It has contributed to torrential rains in Australia and to some of the coldest temperatures in memory in snow-bound parts of China.

    Mr Jarraud told the BBC that the effect was likely to continue into the summer, depressing temperatures globally by a fraction of a degree.

    This would mean that temperatures have not risen globally since 1998 when El Nino warmed the world.

    Watching trends

    A minority of scientists question whether this means global warming has peaked and argue the Earth has proved more resilient to greenhouse gases than predicted.

    Animation of El Nino and La Nina effects

    But Mr Jarraud insisted this was not the case and noted that 2008 temperatures would still be well above average for the century.

    "When you look at climate change you should not look at any particular year," he said. "You should look at trends over a pretty long period and the trend of temperature globally is still very much indicative of warming.

    "La Nina is part of what we call 'variability'. There has always been and there will always be cooler and warmer years, but what is important for climate change is that the trend is up; the climate on average is warming even if there is a temporary cooling because of La Nina."

    China suffered from heavy snow in January

    Adam Scaife, lead scientist for Modelling Climate Variability at the Hadley Centre in Exeter, UK, said their best estimate for 2008 was about 0.4C above the 1961-1990 average, and higher than this if you compared it with further back in the 20th Century.

    Mr Scaife told the BBC: "What's happened now is that La Nina has come along and depressed temperatures slightly but these changes are very small compared to the long-term climate change signal, and in a few years time we are confident that the current record temperature of 1998 will be beaten when the La Nina has ended."

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