11 February 2012 | NewScientist | 19

Slow graphene for faster computers

BLOCK electron flow in one of the most conductive materials known and you might just speed up computing.

Graphene, a sheet-like form of carbon, garnered Konstantin Novoselov and Andre Geim of the University of Manchester, UK, the 2010 Nobel prize in physics, partly due to an astonishing ability to conduct electricity. This property paves the way for graphene-based computers that operate at unprecedented speed. But getting graphene transistors to switch off – which is key to performing calculations – is tough, as they tend to leak some current.

Now Novoselov and colleagues have an answer. They sandwich a layer of molybdenum disulphide between two layers of graphene. The insulating molybdenum prevents electrons from flowing between the graphene layers. But when the sandwich transistor is switched on by applying a voltage, it boosts a quantum effect in which some graphene electrons “tunnel” through the molybdenum layer, creating a flow.

Current leakage in the off state was one-tenth of that of previous graphene transistors (Science, DOI: 10.1126/science.1218461).

Men broodier than women when in the first flush of loveFALLING in love really does make you broody – especially if you are a man. New lovers show greater activation of brain areas related to parental attachment when they see a baby than single people.

This was particularly pronounced in men, hinting that babies may be on their mind from the outset of a relationship. Alternatively, “men may be worried about their partner’s desire for children, and their increased attention to infant stimuli is based on apprehension and the need to be more guarded”,

says Ruth Feldman of Bar-Ilan University in Ramat Gan, Israel, who led the research.

Feldman’s team used electroencephalography to monitor the brain activity of 65 volunteers, including new parents, new lovers and singles as they viewed pictures of infants – including the parents’ own babies – along with neutral pictures.

When viewing unfamiliar babies, parents and new lovers showed greater activation of brain areas associated with parenting, such as the nucleus accumbens,

SOMETIMES the puppets control the puppeteer. Volcanic outbursts on Jupiter’s moon Io pull the strings for brilliant auroras on its parent planet.

Auroras are caused when charged particles hit a planet’s magnetic field. Jupiter has a permanent ring of auroral light on each of its poles, and Io’s volcanoes have long been thought the source of most of the particles responsible for the light show. However, variations in the rings were suspected to be a result of pressure changes in the solar wind.

New observations suggest Io can control these changes as well, say

Bertrand Bonfond of the University of Liège in Belgium and colleagues. They observed Jupiter and Io with the Hubble Space Telescope once a day between February and June 2007 and saw Jupiter’s auroral rings widen mysteriously in that time.

The solution came when NASA’s New Horizons probe flew by Jupiter in May 2007, revealing an unusually large volcanic plume erupting from Io (Geophysical Research Letters, DOI: 10.1029/2011gl050253). “The auroras are really responding to this increased amount of material coming out of Io,” Bonfond says.

Tiny moon controls Jupiter’s auroras

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anterior cingulate and amygdala, than singles. The response was even greater in parents viewing their own child.

Mothers and male lovers showed slightly greater activation of these brain areas than fathers and female lovers (Biological Psychiatry, DOI: 10.1016/j.biopsycho.2011.11.008).

“This suggests that even though the lovers don’t know it, they are physiologically getting ready to respond to infants,” says Helen Fisher of Rutgers University in New York, author of Why We Love.

The good, the bad and the brain scan

CLINT EASTWOOD might sound an unlikely candidate to help investigate the evolution of the brain, but he has lent a helping hand to researchers doing just that. It turns out that brain regions that do the same job in monkeys and humans aren’t always found in the same part of the skull.

Previous studies comparing brains across species tended to assume that human brains were just blown-up versions of monkey brains and that functions are carried out by anatomically similar areas.

To test this idea, Wim Vanduffel of the Harvard Medical School in Boston and colleagues scanned the brains of 24 people and four rhesus monkeys while they watched a clip of The Good, The Bad and The Ugly. They compared brain responses of each individual to the same sensory stimulation, and identified which brain areas had similar functions.

The majority of the human and monkey brain maps lined up, but some areas with a similar function were in completely different places (Nature Methods, DOI: 10.1038/nmeth.1868).

The team say the discovery is crucial to building more accurate models of our evolution. “You can’t assume that because A and B are close together in the monkey brain, they need to be close together in the human brain,” Vanduffel says.

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