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14 July 2012 | NewScientist | 15 Push the boat out of colonisation THE early human colonisation of islands might not have been plain sailing. Instead of using boats to deliberately settle on Indonesian islands, hominins may have arrived as castaways, carried on makeshift rafts after floods. David Wilkinson of Liverpool John Moores University and Graeme Ruxton of the University of St Andrews, both in the UK, used population estimates from the early settlement of Polynesia to model the likely success of island settlement attempts in human prehistory. They found that five young couples had a 40 per cent chance of giving rise to a population of 500 – or founding a population that survived for 500 years. Ten random castaways had only a 20 per cent chance of similar success. But throwing in an additional castaway or four every 50 years raised the chances of an accidental settlement succeeding to 47 per cent (Journal of Human Evolution, DOI: 10.1016/j.jhevol.2012.05.013). Stone tools show that hominins – possibly Homo erectus – reached Flores 1 million years ago. The new finding suggests they may have done so even if they were not mariners. Computer that could outlive the universe is a step closer A “TIME crystal” that can continue to work as a computer even after the heat death of the universe is a step closer to reality. Crystals are three-dimensional objects whose atoms are arranged in regular, repeating patterns. They adopt this structure because it needs the lowest amount of energy possible to maintain. Earlier this year, Frank Wilczek at the Massachusetts Institute of Technology introduced the idea of a time crystal. In such a crystal the atoms would rotate and return to their original location – repeating in time as well as space. Crucially, they would have to be in their lowest energy state as they do so, meaning that they would continue to rotate even after the universe has cooled to a uniform temperature – a state known as heat death (New Scientist, 18 January, p 6). Wilczek proposed a time crystal design using a superconductive ring, but now Tongcang Li at the University of California, Berkeley, and colleagues have an alternative suggestion that may be easier to construct. SILKWORMS may provide a novel way to store vaccines. Preventable infections kill millions of children in poor countries, partly because reliable refrigeration for vaccines isn’t always available. Vaccines are refrigerated to slow the rate at which the biological molecules they contain gradually degrade, largely due to contact with water. Fibroin, a protein in silk, forms stable sheets that contain tiny pockets lined with molecules that repel water. You can trap a biological molecule within these pockets by dissolving it with fibroin in water, then drying it to form a film. Tucked away in a pocket, the molecule is protected. David Kaplan and colleagues at Tufts University in Medford, Massachusetts, made such films with the live measles, mumps and rubella viruses in the MMR vaccine. The films kept the viruses undamaged for six months, even powdered and at temperatures of 45 °C, when regular freeze-dried vaccines degraded rapidly (Proceedings of the National Academy of Sciences, DOI: 10.1073/ pnas.1206210109). Silky solution for storing vaccines DIETER TELEMANS/PANOS PICTURES They propose using an ion trap, a device that holds charged particles in place via an electric field, to form a ring-shaped crystal. By applying a weak static magnetic field, the ions would rotate. Quantum mechanics dictates that the ions would continue to rotate even when the ring is cooled to its lowest energy state. The result is a time crystal (arxiv.org/abs/1206.4772). “I’m very pleased with it,” says Wilczek. “They’ve really come up with something that looks like a realisable experimental design.” Men attracted to ovulation dance WOMEN seeking to impress men on the dance floor might want to consider strutting their stuff when most fertile. Men shown videos of women dancing and walking were most attracted to their moves when the women were close to ovulation. Bernhard Fink, at the University of Göttingen, Germany, and colleagues filmed 48 women while they walked or danced to the drum track of a Robbie Williams song. The women walked and danced once during the most fertile part of their reproductive cycle and again during a non-fertile time. The videos were transformed so that only the outline of each woman’s body was visible. The researchers showed the video clips to 200 men, who were asked to rate the women’s attractiveness on a seven-point scale. They gave women at their most fertile an average rating of 2.88 in the dancing clips and 3.31 in clips showing them walking. This compared with ratings of 2.72 and 2.98 respectively for clips recorded at non-fertile times (Personality and Individual Differences, DOI: 10.1016/j.paid.2012.06.005). Fink speculates that increased attractiveness around ovulation may result from increased levels of oestrogen. “Oestrogen has effects on muscular control, so it’s reasonable to conclude that it could affect body movement,” he says. PLAINPICTURE For new stories every day, visit newscientist.com/news
