For more on these stories go to www.NewScientist.com/section/science-news
IAIN MASTERTON/ALAMY
BEAUTY is in the brain of the beholder: it seems the brains of men and women respond differently to beautiful landscapes. This may stem from the varied evolutionary pressures on the two sexes in our hunter-gatherer ancestors. A team led by Camilo Cela-Conde of the University of the Balearic Islands in Palma, Majorca, Spain, asked males and females whether photographs of natural and urban landscapes were beautiful or not. When they looked at a scene they deemed beautiful, both men and women had greater electrical activity in the parietal region, near the top of the brain. In women, this activation occurred in both halves of the brain, but in men it was restricted to the right hemisphere (Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.0900304106). This might reflect evolutionary differences, the team suggest. In early humans, they say, men were hunters who needed mental maps of distance and direction, while women gathered plants for food and oriented themselves using landmarks. This fits with data that the left brain handles “categorical” spatial relations, such as landmarks, while the right evaluates “coordinate” data, such as distance and direction. The team say that what we find beautiful may have evolved from what our ancestors looked for in a habitat.
Childhood abuse may leave ‘suicide marks’ on genes CHILD abuse appears to leave chemical “caps” on victims’ genes that last into adulthood and which may help to trigger suicide. Last year, Michael Meaney and his colleagues at McGill University in Montreal, Canada, found that in people who had been abused and later committed suicide, more genes were “switched off” in brain tissue taken from the hippocampus – a region involved in mood control – compared with people who had not been abused and who had died in other ways. To see if these differences might
be linked to the abuse itself or to suicidal tendencies in general, the team has now compared samples of hippocampal tissue from 24 people who killed themselves – half of whom were abused or neglected as children, half of whom were not – and from 12 people who were not abused and who died in other ways. The people who had both been abused and committed suicide had more chemical caps on their Nr3c1 gene, compared with the other groups. Nr3c1 is thought to help modulate the response to
stress. They also had lower levels of the messenger RNA that corresponds to the expression of Nr3C1, indicating that the caps had suppressed the gene (Nature Neuroscience, DOI: 10.1038/nn.2270). This suggests the changes in gene expression is linked to childhood abuse or neglect, and not to suicide. However, as people who were abused are more likely to kill themselves, Meaney suspects that the gene changes due to abuse may in turn predispose people to suicide. BRUNO ANDREOTTI/THE MORPHODYNAMICS LAB
What makes for a sexy landscape?
Spotted in space, picked up on Earth IT’S been an extraordinary trip for space rock 2008 TC3. First spotted on 6 October hurtling through space towards Earth, it exploded over Sudan the next day. Now tiny pieces of it have been found. The discovery means that, for the first time, we have detected a space rock ahead of a collision with Earth, watched it streak through the atmosphere and then recovered pieces of it. According to Lindley Johnson of NASA, who reported the find on 16 February at a United Nations meeting in Vienna, the rocks were found in the Sudanese desert by a team from the University of Khartoum. They have an outer crust of singed material characteristic of meteorites. Most meteorites are thought to be pieces of asteroids, but pinning down exactly where they came from is usually impossible. Fortunately, 2008 TC3 was observed while still in space. “It’s often very difficult to get from a streak in the sky to what the orbit was,” says Allan Treiman of the Lunar and Planetary Institute in Houston, Texas. “But if they’ve got its location before it hit the atmosphere, they’re far better off – that’s really wonderful.”
Warmer Earth equals bigger dunes AT 500 metres tall, Earth’s largest sand dunes are already monsters – yet they are set to grow bigger as the world warms. Giant sand dunes are thought to form when smaller dunes crash into each other and pile up. To investigate if anything limits their size, Bruno Andreotti at the Denis Diderot University, Paris, and colleagues calculated what the atmospheric flow looks like around giant dunes. They found that the thickness of the lowest layer of the atmosphere – the boundary layer – controls dune size, with a thicker layer leading to larger
dunes (Nature, vol 457, p 1120). “Once the dune becomes big enough to interact with the boundary layer it creates waves in the air. These waves feed back and interact with the sand below, keeping a lid on the dune size,” explains co-author Brad Murray of Duke University in Durham, North Carolina. Warmer air increases the thickness of the boundary layer, which explains why Earth’s largest dunes are found inland, in the hottest part of the desert. It also suggests that if global warming heats the planet in the right place, then dunes could get bigger.
28 February 2009 | NewScientist | 15