Designer glasses correct red-green colour blindnessGlasses developed to help doctors’ spot veins more easily have a useful side effect: they enhance the ability to see reds and greens.The glasses, made by 2AI Labs in Boise, Idaho, use filters to enhance perception of blood oxygen levels in vessels under the skin. But the filters happen to concentrate their effects around the wavelengths where red-green colour blind people are deficient. "We didn't design them for colour blind people," says Mark Changizi, of 2AI Labs. "But we weren't too surprised to find they help."The glasses are a correction rather than a cure, and amplify reds and greens at the expense of discerning yellows and blues. Changizi has suggested that primate colour vision evolved to help detect blood oxygen levels and so help sense health and emotion. The glasses were developed to enhance this ability and different versions are currently being tested by doctors to help spot bruising, and by poker players to help detect the subdued blushes of bluffing opponents.
New map pinpoints cities to avoid as sea levels riseSydney, Tokyo and Buenos Aires should watch out. These cities will experience some of the greatest sea level rises by 2100, according to one of the most comprehensive predictions to date.Sea levels have been rising sporadically for over 100 years. Several processes are at work, says Mahé Perrette of the Potsdam Institute for Climate Impact Research in Germany. Some land is sinking, some is rising. Stronger currents create slopes in sea surface, and since all things with mass exert a gravitational pull, disappearing ice sheets lead to a fall in sea levels in their surrounding areas.Perrette has modelled all of these effects and calculated local sea level rises in 2100 for the entire planet. While the global average rise is predicted to be between 30 and 106 centimetres, he says tropical seas will rise 10 or 20% more, while polar seas will see a below-average rise. Coasts around the Indian Ocean will be hard hit, as will Japan, south-east Australia and Argentina.New York's position may be less perilous than previously thought. A weakening of the Atlantic Gulf Stream will cause water to slop westwards, triggering a rapid rise on the eastern seaboard, but this will be counteracted by Greenland's weaker gravitational pull.
Ancestor of humans and other mammals was small furry insect eaterAn identikit picture of a small furry ancestor of humans and most other mammals has been pieced together by scientists.The shrew-like creature weighed less than half a pound, had a long tail and ate insects. It evolved some 200,000 years after the extinction of the dinosaurs 65 million years ago.From this small beginning sprang every "placental" mammal, which give birth to mature live young, including dogs, cats, rodents, whales and humans.Placental mammals are the largest branch of the mammalian family tree, with more than 5100 living species. Non-placental mammals comprise kangaroos and other marsupials, and egg-laying monotremes such as the duck-billed platypus.Experts recorded 4500 physical traits for 86 mammalian species, including 40 that are now extinct. The features, including the presence or absence of wings, teeth, and bone types, produced a data set ten times larger than any used before to study mammalian ancestry.Combined with molecular information from DNA samples, it allowed the scientists to pinpoint the likely start of the story of placental mammals.By Michael O'Sullivan