the-BA : Science News Digest - 30 November 2007

A Topi 'taking a rest' (Image copyright: istockphoto.com)

In the science news this week: a protein that rejuvenates skin (at least in mice), an explanation for Venus's inhospitable climate and flying foxes fall foul of climate change on Earth. Plus, female African antelopes tire out their men...

Despite the fact that Venus is often referred to as Earth’s twin, due to their similar size, mass and chemical composition, their climates and habitability couldn’t be more different. The proximity of Venus to the Sun cannot account for these huge differences – the surface temperature on Venus averages a searing 450 degrees Celcius – but now the Venus Express space probe has provided data which goes some way to explaining why the planet became so inhospitable to life.

According to a report in Nature, the findings suggest that the planet may once have been much like Earth, with vast oceans of water supporting life, and that the change occurred because a series of chance events.

It seems that lack of a protective magnetic field left the planet vulnerable to solar wind. This high-speed stream of charged particles stripped away water by breaking molecules into oxygen and hydrogen atoms that then escaped into space. Without this water, carbon dioxide in the atmosphere couldn’t be trapped as carbonate rocks. The resulting build up of atmospheric carbon dioxide led to a runaway greenhouse effect.

The probe also revealed that Venus experiences lightning strikes which has important implications for the chemistry of the planet’s atmosphere, reported the Independent.
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At a meeting in Houston, Texas, NASA revealed its strategy for sending humans to Mars within the next few decades. BBC News reported that the agency proposes dispatching a minimal crew in 2031 for a 30-month round trip. A spacecraft powered by an advanced cryogenic fuel propulsion system would take six to seven months to reach the Red planet, and the cargo lander and surface would be sent on ahead of the crew – launching in 2028 and 2029.

Since the options for aborting the mission or providing the crew with new supplies would be extremely limited, they would need to be highly self-sufficient: able to maintain and repair equipment, and growing their own fruit and vegetables, while air and water would be recycled.

Challenges remain before any such mission can take place. These include the development of effective solutions for protecting astronauts from the high levels of cosmic radiation they would be exposed to on the journey and on the Martian surface, as well as medical equipment to diagnose and treat illnesses and injuries. Testing of systems could take place on the Moon, say NASA.
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The Hubble Space Telescope has provided a spectacular view of a distant spiral galaxy similar to the Milky Way. Nicknamed the ‘Phantom Galaxy’ because it is so faint and difficult to see through amateur telescopes, Messier 74 is located around 32 million light years away.
(See the image for yourself in the Telegraph)
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Meanwhile, other scientists have produced the most detailed map of Antarctica to date. Constructed from more than 1,000 views provided mainly by the American Landsat spacecraft, the true colour mosaic is said to be 10 times more detailed than any that have been made before and will provide invaluable information for those planning research trips to the region, as well helping researchers interpret land elevation changes in hard-to-reach areas.
(Read more at BBC News)
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Flying foxes are falling foul of the effects climate change, say researchers, with more than 30,000 estimated to have died during heat waves since 1994. Mass deaths caused by heat stress have occurred at least 19 times in parts of Australia since that date, compared to only three anecdotal reports of similar occurrences prior to 1994. They are the first large mammal other than humans to be shown to suffer mass mortality during a heat wave.

The large nocturnal bats are vulnerable because they roost in trees during the day, rather than sheltering in caves or other cooler alternatives. The study found that the bats started to die as temperatures approached 42 degrees Celcius, reported the Times.
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Meanwhile, in the run up to next month’s climate change conference in Bali, the United Nations’s annual human development report has highlighted the plight of the world’s poorest people. The report states that 98 per cent of people affected by climate disasters during 2000-04 lived in the developing world.

The UN says a huge political commitment is needed – of the type that led to the development of the atomic bomb and put a man on the moon – in order to limit a global temperature increase to two degrees Celcius. It stressed that failure of the richer countries to act now would be the 21st-century equivalent of the lack of leadership that led to World Wars I and II.
(Read more in the Guardian)
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As Sir David King’s tenure as the Government’s Chief Scientific Adviser comes to an end and he prepares to take up his position as President of the BA, he has given a valedictory speech to a group of senior scientists at the Foundation for Science and Technology. BBC News shared his reflexions on developments during his time in office and some of his thoughts about the future of British science, including his support for GM technology. Meanwhile, BBC science correspondent Pallab Ghosh provided his thoughts on Sir David’s lasting legacy.
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Back in February, the Science News Digest carried news that the world’s first ‘bionic arm’ had given its recipient back a sense of feeling after sensory nerves were routed to a patch on her chest. Since then, Claudia Mitchell has tested a prototype of a prosthetic limb that enabled her to sense her hand closing around objects and lifting them, reports the Guardian.

The team at the Rehabilitation Institute of Chicago are so impressed with the results seen for Claudia and another man who has also had the operation that they have operated on two further patients. Particularly remarkable is the finding that nerves that have been out of use for more than a year are able to function and transmit sensation signals when grafted onto new tissues. Sensory neurophysiologist Paul Marasco says prosthetic limbs that can recreate a sense of touch are expected to be widely available in two to four years.
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A scanner has been developed that can produce rotatable 3D body images of unprecedented quality whilst limiting patients’ exposure to radiation. The new 256-slice CT machine combines multiple x-ray pictures using computer technology. The scanning method is 22 per cent faster than current systems, meaning that exposure to x-rays is reduced – by as much as 80 per cent.

Steve Ruckowski, Chief Executive of Philips Medical Systems, told BBC News: ‘It’s so powerful it can capture an image of the entire heart in just two beats.’
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Another 3D scanning technology, this time to identify breast cancer, is being trialled in America and initial results indicate it could improve detection rates substantially. 1,093 women underwent both a standard mammography screening, plus a new stereoscopic scan – where two images are taken eight degrees apart and then combined to create a 3D image. The new technique missed 40 per cent fewer tumours.
(The Guardian)
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BBC News reported that scientists have rejuvenated the skin of ageing mice by blocking the action of the NF-kappa-B protein – found to control the activity of many genes that play a part in the ageing process. Not only did the mice’s skin look more youthful, it had the same genetic profile of that of newborn mice.

The researchers stress that it is unlikely to lead to a ‘fountain of youth’, particularly since the protein has been implicated in cancer and the regulation of the immune system and so any application in humans would most likely have to be on a short-term basis. However, potentially, manipulation of the protein could help older people heal more quickly from injury.

According to lead researcher Dr Howard Chang, from the Stanford School of Medicine in California, the findings support the theory that ageing is caused by specific genetic changes rather than gradual wear and tear.
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In other news, scans have revealed that the brains of paedophiles contain significantly less white matter connecting six areas known to play a role in sexual arousal. Since white matter ‘wires’ different brain areas together, it suggests paedophilia may be the result of faulty connections. The study, published in the Journal of Psychiatry Research, compared MRI brain scans of 127 men, who were either paedophiles or had committed non-sexual crimes, and found specific differences in activity in parts of the brain.

Lead researcher Dr James Cantor, from the Centre for Addiction and Mental Health in Toronto, stressed that this did not suggest paedophiles shouldn’t be held criminally responsible for their actions. ‘Not being able to choose your sexual interests doesn’t mean you can’t choose what you do,’ he told BBC News.
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It seems one of our ancient human relatives that lived 1.5-2 million years ago may have had a gorilla-style love life involving female ‘harems’. Scientists from University College London compared 35 fossilised specimens of Paranthropus robustus and found evidence of sexual dimorphism – where males and females grow to significantly different sizes. Such differences are usually associated throughout the animal kingdom with particular mating behaviour where a dominant male has access to plenty of females and smaller subordinate males have limited breeding opportunities.

’...The males continued to grow well into adulthood, just as they do in gorillas,’ said lead researcher Charles Lockwood. ‘This resulted in a much bigger size difference between males and females than we see today. It’s common knowledge that boys mature later than girls, but in humans the difference is much less marked than in some primates.’
(The Times)
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Using animated caricatures could help police identify suspects, new research has found. The system starts with a witness’s recollection of a face and then morphs it so that remembered features are exaggerated.

Psychologists from the University of Central Lancashire and Stirling University, who developed the technology, found that it helped witnesses recognise faces even after a two day delay – resulting in successful identification 26 per cent of the time, compared to just 3.7 per cent when standard static Photofits were used.
(The Times)
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And finally...

In a reversal of common animal mating situations, male Topi (an African antelope) are so sexually stretched that they often have to turn females away. While the mating season lasts six weeks, individual females are fertile for just one day, and so there is intense pressure to mate as often as possible to increase their chances of getting pregnant.

The fittest males find themselves in such demand that they have been observed to withhold their services from females they have already mated with, conserving their sperm for new partners. The study published in Current Biology found that males who didn’t pace themselves were at risk of collapsing of exhaustion and being eaten by predators.

And the award for the headline with the worst/best pun goes to... the Telegraph for ‘Not tonight deer... No sex for topi antelope’.