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Leaf loss adds to frogs' woes
Research news and discovery
In brief–
GRANT FAINT/IMAGE BANK
Anti-cancer pill
Flying in V-shape provides best views for least effort FOR human pilots, formation flying takes years to master, but migratory birds have it down to a fine art. Yet the reason why geese, for example, fly in a V-shape has long been something of a mystery. Now a computer model has combined two competing theories. The first suggests that the formation has an aerodynamic advantage – each bird creates an upwash behind its wing tips, giving those following it an extra lift. The second holds that flying in a slightly skewed position relative to the bird in front allows for unimpaired vision. Valmir Barbosa and Andre Nathan at the Federal
University of Rio de Janeiro, Brazil, created computer models of flocks of between 15 and 35 birds, taking both theories into account. Each bird was allowed to seek out the one nearest to it, and to position itself so that its view was not blocked. It could then adjust its position to take advantage of any improved aerodynamics (www.arxiv.org/cs/0611032). The results showed that both theories hold true. Previous computer models that did not take both into account were unable to reproduce V-formations, says Barbosa, “but we have found that these formations occur regardless of how the birds are positioned initially”. The artificial birds also settled into other patterns seen in nature, such as W-formations. “This is an appealing instance of how complexity emerges from simple rules.”
Leaf loss adds to frogs’ woes MORE bad news to set amphibians’ eyes bulging. The catastrophic declines in frog and salamander populations in recent years may be even more widespread than had been feared – and the devastation seems to extend to reptiles. Steven Whitfield of Florida International University in Miami and colleagues studied data on ground-dwelling reptiles and amphibians collected over the 16 | NewScientist | 21 April 2007
070421_N_In brief.indd 16
past 35 years at the La Selva Biological Station in Costa Rica. The counts show a steady decline in the numbers of reptiles and amphibians in native forest, while numbers increased in abandoned cacao plantations (Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.0611256104). Fungal diseases or pesticide contamination, blamed for amphibians’ decline elsewhere, are
unlikely to be behind the declines at La Selva, since they would affect abandoned plantations as well as native forest. The researchers suggest the cause may be a change to a warmer, wetter climate, which reduces tree growth and may lead to a thinner layer of leaf litter, in which the animals live. Cacao plantations produce a heavier layer of this leaf litter. Pesticides and fungus have been blamed for the decline in Costa Rica’s mountain amphibians (New Scientist, 3 March, p 17).
REGULAR aspirin use may protect more than just your heart – it could also reduce your risk of getting cancer. Aditya Bardia and colleagues at the Mayo Clinic College of Medicine in Rochester, Minnesota, analysed the cancer history of more than 22,000 postmenopausal women over 12 years. Those who reported taking aspirin regularly at the start of the study were 16 per cent less likely to develop cancer and 13 per cent less likely to die from it during that time. The only lifestyle factor that influenced the results was smoking, which reduced the protective effect slightly. Bardia says aspirin’s antiinflammatory action is probably responsible, although a similar effect was not seen with other anti-inflammatories, such as ibuprofen. The findings were presented at a meeting of the American Association for Cancer Research in Los Angeles this week.
Gene makes some people fatter EVER wondered why you pile on the kilos while others can eat what they like and stay slim? It could be because you have an altered version of a gene called FTO. Around half of white Europeans have one altered copy of FTO, which increases the risk of obesity by 30 per cent, while a further 16 per cent hold two altered copies, which raises the risk by 70 per cent. Mark McCarthy at the University of Oxford and his colleagues made the discovery after analysing the DNA and physical health of 39,000 white people in the UK and Finland. People with two altered copies of the gene were on average 3 kilograms heavier than those with normal copies (Science, DOI: 10.1126/science.1141634). www.newscientist.com
16/4/07 4:28:00 pm
In brief–
GRANT FAINT/IMAGE BANK
Anti-cancer pill
Flying in V-shape provides best views for least effort FOR human pilots, formation flying takes years to master, but migratory birds have it down to a fine art. Yet the reason why geese, for example, fly in a V-shape has long been something of a mystery. Now a computer model has combined two competing theories. The first suggests that the formation has an aerodynamic advantage – each bird creates an upwash behind its wing tips, giving those following it an extra lift. The second holds that flying in a slightly skewed position relative to the bird in front allows for unimpaired vision. Valmir Barbosa and Andre Nathan at the Federal
University of Rio de Janeiro, Brazil, created computer models of flocks of between 15 and 35 birds, taking both theories into account. Each bird was allowed to seek out the one nearest to it, and to position itself so that its view was not blocked. It could then adjust its position to take advantage of any improved aerodynamics (www.arxiv.org/cs/0611032). The results showed that both theories hold true. Previous computer models that did not take both into account were unable to reproduce V-formations, says Barbosa, “but we have found that these formations occur regardless of how the birds are positioned initially”. The artificial birds also settled into other patterns seen in nature, such as W-formations. “This is an appealing instance of how complexity emerges from simple rules.”
Leaf loss adds to frogs’ woes MORE bad news to set amphibians’ eyes bulging. The catastrophic declines in frog and salamander populations in recent years may be even more widespread than had been feared – and the devastation seems to extend to reptiles. Steven Whitfield of Florida International University in Miami and colleagues studied data on ground-dwelling reptiles and amphibians collected over the 16 | NewScientist | 21 April 2007
070421_N_In brief.indd 16
past 35 years at the La Selva Biological Station in Costa Rica. The counts show a steady decline in the numbers of reptiles and amphibians in native forest, while numbers increased in abandoned cacao plantations (Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.0611256104). Fungal diseases or pesticide contamination, blamed for amphibians’ decline elsewhere, are
unlikely to be behind the declines at La Selva, since they would affect abandoned plantations as well as native forest. The researchers suggest the cause may be a change to a warmer, wetter climate, which reduces tree growth and may lead to a thinner layer of leaf litter, in which the animals live. Cacao plantations produce a heavier layer of this leaf litter. Pesticides and fungus have been blamed for the decline in Costa Rica’s mountain amphibians (New Scientist, 3 March, p 17).
REGULAR aspirin use may protect more than just your heart – it could also reduce your risk of getting cancer. Aditya Bardia and colleagues at the Mayo Clinic College of Medicine in Rochester, Minnesota, analysed the cancer history of more than 22,000 postmenopausal women over 12 years. Those who reported taking aspirin regularly at the start of the study were 16 per cent less likely to develop cancer and 13 per cent less likely to die from it during that time. The only lifestyle factor that influenced the results was smoking, which reduced the protective effect slightly. Bardia says aspirin’s antiinflammatory action is probably responsible, although a similar effect was not seen with other anti-inflammatories, such as ibuprofen. The findings were presented at a meeting of the American Association for Cancer Research in Los Angeles this week.
Gene makes some people fatter EVER wondered why you pile on the kilos while others can eat what they like and stay slim? It could be because you have an altered version of a gene called FTO. Around half of white Europeans have one altered copy of FTO, which increases the risk of obesity by 30 per cent, while a further 16 per cent hold two altered copies, which raises the risk by 70 per cent. Mark McCarthy at the University of Oxford and his colleagues made the discovery after analysing the DNA and physical health of 39,000 white people in the UK and Finland. People with two altered copies of the gene were on average 3 kilograms heavier than those with normal copies (Science, DOI: 10.1126/science.1141634). www.newscientist.com
16/4/07 4:28:00 pm