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Where will aliens live?
IF ALIENS do exist there are only a limited number of places in the universe in which they might live, according to new research. A team of scientists from Bristol University, the University of Washington and Nasa have argued that the atmosphere on a planet has to be rich in oxygen for complex life to exist.
On Earth, it took almost 4bn years, half the predicted lifetime of Sun, for oxygen levels to reach the point where animals could evolve. The researchers have concluded that life on other planets orbiting short-lived suns would probably not have enough time to evolve into complex forms. “This is a major limiting factor for the evolution of life on otherwise potentially habitable planets,” said David Catling, one of the country’s first professors of astrobiology, from Bristol University.
The research is due to be published in the journal Astrobiology. Prof Catling, who recently returned from the US to take up the Marie Curie chair at Bristol, is part of the scientific team behind the Nasa Mars spacecraft Phoenix Lander. The space agency, where Prof Catling worked for six years, recently got the go-ahead to put a lander on Mars in 2007.
A robotic arm on the craft will dig one metre into the soil to examine its chemistry. “A key objective is to establish whether Mars ever had an environment conducive to more simple life,” Prof Catling said. In his new position, the professor hopes to conduct further research into how Earth’s atmosphere originated and evolved. — Dawn/The Guardian News Service
Life in the darkest place
US researchers have found evidence of photosynthesis — the magic that turns solar energy and carbon dioxide into lettuce leaves and little green apples — more than a mile below the ocean surface. Little more than two decades ago, researchers were astonished to find the first communities flourishing at such depths, deriving their energy from the heat from hydrothermal vents.
Now, 2,400 metres under the Pacific, off Mexico, Thomas Beatty of the University of British Columbia and colleagues have found a bacterium that makes a living off the imperceptible light provided by gushers of water emerging at 350C into the almost freezing ocean waters. Sunlight can penetrate as far as 200m, getting ever more faint with depth.
But the researchers found a sulphur-eating photosynthetic organism in samples taken near a vent more than 10 times as deep. Since the creature could not possibly harvest sunlight at that depth, it must be getting light energy from another source, they report in Proceedings of the National Academy of Sciences. That source could only be the very faint glow of very hot water.
The discovery has implications for the search for life beyond Earth — perhaps in the liquid ocean thought to slosh beneath the thick ice of Jupiter’s moon Europa or in some aquifer on Mars. “Life finds a way,” says Robert Blankenship of Arizona State University, one of the team.— Dawn/The Guardian News Service
London accused on superbugs
The British government was recently accused by a powerful committee of MPs of failing to tackle the crisis in hospital-acquired infections, of which the “superbug” MRSA is just a small part. The public accounts committee, which monitors government spending, said little had been done since its investigation four years ago.
“It is astonishing that poor ward cleanliness, lax hand-washing practices, a shortage of isolation facilities and high bed occupancy rates are still plaguing NHS hospitals,” the chairman, Edward Leigh, said.
MRSA rates were still among the worst in Europe, but the bug accounted for only 6 per cent of hospital-acquired infection. The true scale of the problem was still not clear, because “little has been done to dispel the fog of ignorance,” he said.
The much-quoted figure of 5,000 deaths a year from infections picked up in hospitals was not only “rough and ready” but it dated from American studies in the 1980s. There was still no mandatory reporting scheme for all hospital-acquired infections, as the committee had recommended, and MRSA infection is included on a death certificate only if the doctor thinks fit. — Dawn/The Guardian News Service
Mangroves and tsunamis
Mangroves, like coral reefs and tropical rainforests, are among the richest habitats on the planet. They are also among the most threatened: stripped away to make room for shrimp farms, tourist beaches, ports and even cities.
However, disaster experts tend to argue, in their natural state they might have provided a buffer to protect people from tsunamis and coastal storms. A team from Belgium, Sri Lanka, Kenya and India report in Current Biology that they investigated the impact of the Dec 26 tsunami on 24 mangrove sites in Sri Lanka.
Mangrove fringes near the water’s edge seemed to have absorbed most of the energy from the waves, with few trees uprooted. But even seemingly insignificant human changes to some of the sites seemed to enhance the tsunami’s damaging power. — Dawn/The Guardian News Service
Women and soya
Women who eat soya-based foods may be damaging their chances of becoming pregnant and should give up eating them during the most fertile part of their monthly cycle, a scientist said recently.
Laboratory tests suggest the naturally occurring chemical destroys the mechanism that allows sperm to dock with women’s eggs, said Prof Lynn Fraser at the European Society of Human Reproduction and Embryology in Copenhagen. Her team is about to test the theory.
“It might be practical, if you are in the habit of eating lots of soya-based products, to restrict your diet for a short time over your window of ovulation,” Prof Fraser said. The researcher, of King’s College, London, added that sperm could “hang around” for four days in women’s organs.
Soya, present in products such as bread, milk, margarine, ready meals and sauce, is often lauded for preventing damage to cells, and protecting them against heart disease and some cancers.
But even the Vegetarian Society went along with Prof Fraser’s advice: “For anyone struggling to become pregnant, avoiding soya products for a few days a month is worth a try if there is even a slim chance that it will help fertility.” — Dawn/The Guardian News Service
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