Monday, July 21, 2008

All Wet? Astronomers Claim Discovery of Earth-like Planet

A team of astronomers announced they have discovered the smallest and potentially most Earth-like extrasolar planet yet. Five times as massive as Earth, it orbits a relatively cool star at a distance that would provide earthly temperatures as well, signaling the possibility of liquid water.

"The separation between the planet and its star is just right for having liquid water at its surface," says astronomer and team spokesperson Stephane Udry of the Observatory of Geneva in Versoix, Switzerland. "That's why we are a bit excited."

But researchers do not yet know if the planet contains water, if it is truly rocky like Earth, which might make it hospitable to life as we know it, or whether it is blanketed by a thick atmosphere. "What we have," Udry says, "is the minimum mass of the planet and its separation" from its star.

The researchers say they detected the presence of two new extrasolar planets (exoplanets) around a red dwarf star, Gliese 581, 20.5 light-years away in the constellation Libra, based on slight motions of the star. Their discovery brings the total number of planets orbiting Gliese 581 to three; two years ago they made the initial finding of a planet there.

Udry says the group has submitted a paper for peer review and plans to publish a draft this week. "The claim is extremely interesting and the team is very credible," says astronomer David Charbonneau of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., adding that he cannot judge the validity of the claim until the team publishes its data.

Researchers believe that many smallish exoplanets exist, but so far they have only found 13 "super Earths" weighing in at less than 20 Earth masses, compared with more than 200 heavier gaseous planets. Udry's group searches for smaller planets using a telescope called HARPS (High Accuracy Radial velocity Planet Searcher), which looks for stars that wobble slightly.

As a planet orbits, it pulls a star back and forth. The range of motion increases with the planet's mass, and the time needed for one orbit (or one back and forth) translates into its distance from the star.

The smaller of the new planets, dubbed Gliese 581 c, orbits at one fourteenth the distance between Earth and the sun. But the red dwarf is 50 times cooler than the sun. The group estimates that the planet would experience temperatures in the zero-to-40-degree-Celsius (32-to-104-Fahrenheit) range.

"It's sort of at the 'Goldilocks' distance," says Charbonneau—closer to its star and the heat would vaporize any water; farther away and water would freeze.

The big question is whether there really is water on Gliese 581 c's surface, which requires that its surface be solid. Udry says planets smaller than 15 Earth masses are likely to be rocky or icy.

Charbonneau is more cautious. A five-Earth-mass planet "sort of looks like Earth, but it sort of looks like Neptune. So which is it?" he says. "There's just no way to know."

Prior Water Claim Evaporated?

In related news, a recent report of water vapor on gaseous extrasolar planet HD 209458 b may have been premature. Earlier this month, an astronomer claimed as much based on measurements of starlight passing through the planet's atmosphere.

Charbonneau, who led the team that collected the data, says the analysis is unconvincing because the telescope itself may have introduced variation that could be mistaken for fluctuation in light coming from the star.

Observations by the Hubble or Spitzer space telescopes may resolve the question once and for all in coming months, Charbonneau says.

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Hi-tech is turning us all into time-wasters

Time-wasting is not just an irritating habit. It is an affliction that ruins millions of lives and often requires therapy and other treatment for sufferers, psychologists have warned.

According to new research, one person in five now suffers from the problem so badly that their careers, relationships and health are threatened. Many researchers blame computers and mobile phones for providing too many distractions for people.

'The subject is seen as joke,' said Professor Joseph Ferrari of DePaul University in Chicago. 'But the social and economic implications are huge. These people need therapy. They need to change the way they act and think.'

Ferrari says that chronic procrastination is now so serious a condition it needs to be recognised by clinicians. In a study to be published later this year, he estimates that 15 to 20 per cent of people are chronic procrastinators. 'We now have data on 4,000 people, and it doesn't seem to matter what age you are, or your sex or background.'

He has devised a questionnaire to help diagnose the condition, which he says is 'much more common than depression or common phobias'. Procrastination also has knock-on effects - it encourages depression, lowers self-esteem, causes insomnia, and indirectly affects health by discouraging visits to the dentist or doctor. Sufferers are also more likely to have accidents at home involving unmended appliances.

Cognitive psychologist Professor John Maule, of Leeds University's business school, agreed that a significant proportion of the population were prone to procrastination, and argued that mood changes - particularly depression - might be to blame.

Research by Professor Piers Steel from Calgary University indicates that the incidence of chronic procrastination has risen dramatically in recent decades, from one person in 20 to one in four, as new technology has come to dominate our lives. Even the beeps notifying the arrival of email are said to be causing a 0.5 per cent drop in gross domestic product in the United States, costing the economy $70bn a year.

Ferrari, however, is less convinced that new technology is to blame for time-wasting. 'People have wasted time for centuries,' he said. 'Lots of people, particularly people who often have to work under time constraints, put work off because they kid themselves that they work best when under pressure, when there's a deadline.

'Studies have shown this isn't true. They're conveniently forgetting the times when it all went horribly wrong - and selectively remembering the odd occasion when things went well under severe time pressure.'

Once, humans probably did have stronger excuses for delaying chores that didn't need immediate attention, say brain scientists such as Alan Sanfey at Arizona University, whose work has shed light on the evolutionary origins of procrastination.

It appears that the brain is divided into two parts. One triggers 'automatic responses' which take precedence over everything else - such as fleeing sabre-toothed tigers. The other governs 'deliberate responses' - writing that report due next week or booking a visit to the optician. Evolution has dictated that the former take precedence. Today there aren't any sabre-toothed tigers, but we still put things off.

Male lust is blind, research suggests

Men have long been accused of judging women on looks alone, but even the plainest Jane can get their hormones raging, a study has found.

Research involving a group of male students found that their levels of the hormone testosterone increased to the same extent whether they were talking to a young woman they found attractive – or to one they didn't fancy much at all.

After 300 seconds alone in the same room as a woman they had never met before, and in some cases did not find particularly attractive, the men's testosterone levels of the hormone had shot up by an average of around eight per cent.

The study's authors believe the rise in testosterone may be an automatic and unconscious reaction that has evolved in man when faced with a woman, to prepare him for possible mating opportunities.

The rising levels may then fuel more visible changes in male behaviour that occur in the presence of a woman, including a squaring of shoulders, an upright posture, and greater use of hands - and even, it is suggested, a flaring of the nostrils.

The rise in the male hormone may also be the reason why men are more likely to tell women exaggerated stories about their job, career, education and earnings, the researchers believe. The study, published in the journal Hormones and Behaviour, involved 63 male students aged 21 to 25 who were not aware of the purpose of the study.

Their testosterone levels were measured with saliva samples and they were then taken to another room by a researcher under the guise of being there to solve a sudoku puzzle.

In the same room another man or a woman appeared to be solving a similar puzzle, but he or she was in fact acting as the so-called stimulus.

The women were chosen on the basis of being moderately attractive for the student population.

The researcher then made the excuse that he did not have the correct puzzle for the participant and left the room to get it. The two were then left alone to wait together for five minutes. The stimulus people were told to engage in friendly conversation in a natural manner, or allow long pauses if the man elected not to talk.

After five minutes, the experimenter returned with the correct puzzle, and then left the room with the stimulus person.

Fifteen minutes later, the experimenter returned to collect the puzzle from the man, and to take a second saliva sample. Comparison of the saliva tests showed that testosterone levels rapidly increased by an average of 7.8 per cent after the five minute contact with a woman.

Men who were rated as more aggressive or dominant types had gone up even higher. The results also show that testosterone levels did not change when they were in the room with another man.

The men were also asked to rate the attractiveness of the woman in the room, and the results show that the testosterone increase was not influenced by the perceived attractiveness of the women.

Leander van der Meij, who led the study at the University of Groningen in Holland, said: "We found a testosterone increase after only five minutes of exposure to a woman. Our results suggest that the increase in testosterone levels that we found, may be an automatic male response that activates receptors in organs and the nervous system to prepare the human body for mate attraction."

The researchers believe the results suggest that one of the ultimate functions of testosterone may be to attract mates. One way it may do that is by orchestrating changes in appearance and behaviour that may increase their attractiveness.

This idea is supported by evidence that dominance behaviours of men increases their desirability as a date and by research showing that men who exhibit more dominant-like behaviour make more frequent successful contact with women.

Mr van der Meij added: "We showed that testosterone levels increased in men after contact with women. This increase is probably an important mechanism through which men acquire partners.

"Testosterone levels rose motivating men to seek mating opportunities. That in turn triggers changes in unconscious behaviour designed to attract a mate. The rise in levels of the hormone bring about changes in way men display themselves.

"Once levels have risen, they can display more dominant behaviour. They talk more with their hands, there is more eye contact, their posture is more upright, and they are more likely to tell stories designed to impress the woman. We known that women can be attracted by these kinds of things. All this, we believe, may be fuelled by the rise in testosterone that we have found."

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Gene found that limits alcohol risk

As many as one in four Britons have a much-reduced risk of developing alcohol-related cancer thanks to their genetic make-up, scientists have discovered. Researchers have identified two genes that quickly flush alcohol out of the system, thus reducing its carcinogenic effect. People carrying one or both of the genes may have only half the chance of developing mouth, throat and oesophageal cancers that are strongly associated with drinking.

The genes involved are rare versions of ADH7 and ADH1B. The ADH range of genes help the body to process alcohol. Everyone carries two versions of each of these genes, one inherited from each parent, but only 15 to 20 per cent of the UK population have ADH7, while around another 5 per cent have ADH1B.

A study of 9,000 people has shown for the first time that people carrying one or both of these rare gene variants have a much lower risk of getting head or neck cancer than those who have the common versions. For example, those with ADH1B have only half the chance of developing such cancers and people with ADH7 are at a 32 per cent reduced risk.

Researchers say the findings are significant because it is the first time they have pinned down genes that have a protective effect against alcohol. 'We don't know how the protection occurs, but we do now know that these genes have that effect, and that could be hugely useful in giving us a much broader understanding of cancer processes in general,' said Professor Martin Wiseman, medical and scientific adviser to the World Cancer Research Fund, which helped to fund the study.

Alcohol is one of the major causes of cancer, along with smoking and diet. It is estimated to be responsible for about 5 per cent of the 285,000 new cases of cancer diagnosed every year. Experts say convincing evidence shows that it is linked to cancers of the mouth, breast, bowel, liver, pharynx, larynx and oesophagus.

Health experts welcomed the findings, but warned that they should not be interpreted as a green light to drink heavily. 'This shouldn't have any direct effect on people's drinking behaviour. Those people with one or both of these rare gene variants are lucky in that they are at lesser risk of developing these cancers. Having up to half the risk is significant,' said Wiseman. 'But they still face some risk. So the advice to them wouldn't be, "Go away and drink". It would be, "For cancer prevention, avoid alcohol entirely if you can and, if you do drink, limit it to one drink a day for a woman and two drinks a day for a man".'

Those who carry such genes would not know it, as a family doctor cannot tell and there is no reliable test to tell someone their genetic make-up that can be easily accessed, Wiseman added.

Dr Paul Brennan, the researcher who led the study at the International Agency for Research on Cancer in France, said: 'Every human being has the seven [ADH] genes that, when you drink a beer or whisky, start to break down the ethanol in the alcohol which many believe is the cancer-causing agent. But those 20 to 25 per cent of people who have one or both are gene variants - if they drink alcohol, their risk of getting these head and neck cancers is reduced by about half.'

The discovery made by Brennan and his team is outlined in a paper published in the journal Nature Genetics. They found that 20.5 per cent of people in Manchester, 16 per cent in Edinburgh and 15 per cent in Newcastle carry the rare variant of ADH7, while 6 per cent of people in the Scottish capital and 4 per cent of those in both English cities have the uncommon form of ADH1B.

Now that the two genes have been identified, scientists will start to examine how the proteins they produce assist the body by aiding the natural process of cleansing toxins. This has long-term potential to help in the development of drugs that might mitigate the damaging effects of alcohol consumption.

While the study is good news for up to a quarter of the population, it also provides further evidence of how drinking even moderate amounts of alcohol can increase the risk of getting cancer.

Dr Julie Sharp, science information manager at Cancer Research UK, said: 'This adds to existing evidence that alcohol increases the risk of these types of cancer. It also highlights that both our genes and our lifestyle influence cancer risk and will help scientists understand more about the disease.'

However, Sharp added: 'It's important to stress that these results don't mean that people can drink too much and hope they won't be at risk. These genetic variants are rare and still don't protect people totally from the damage caused by alcohol.'

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