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A STRAIN of loud laboratory mice that show all the signs of having autism could help us understand the complicated genetics of this mysterious condition.

Previous studies of the BTBR strain of mice have found that they have two of the three symptoms normally used to diagnose autism in people: repetitive behaviours and decreased social interaction.

Now Maria Luisa Scattoni of the National Institute of Mental Health in Bethesda, Maryland, and colleagues have found that they also display a third trait associated with autism.

The researchers separated baby mice of different strains from their mothers. The pups made noises to bring mum back, rather like human babies crying. These ultrasonic calls are too high for the human ear to hear, but the researchers

detected them with special microphones and split them into 10 different “flavours”.

Most mice in the study used all 10 flavours. The vocabulary of the BTBR strain, however, was limited to four flavours, including “harmonic” calls that contain multiple simultaneous sounds. BTBR mice also called louder and for longer periods (PLoS ONE, DOI: 10.1371/journal.pone.0003067 ).

The team suggests these abnormal vocalisations can be likened to the third set of traits found in children with autism, who sometimes hum, grunt and squeal loudly and inappropriately. “This is similar to what others have found in autistic infants,” says Scattoni.

If mice communicate meaningful information to each other using ultrasonic sounds, then those with abnormal calls could be used to help identify genetic and environmental causes of autism, which still remain a mystery. Epidemiologist Mady Hornig , who studies autism at Columbia University in New York, says: “We can begin to understand how the genetic mechanisms may all be working together.”

BARACK OBAMA or John McCain? Floating voters in the upcoming US election may already have made up their minds – they just don’t know it yet.

Bertram Gawronski, a social psychologist at the University of Western Ontario in London, Canada, and his colleagues asked 129 residents of Vicenza, Italy, whether they would support a controversial proposal to enlarge the city’s US military base. To measure subconscious biases, the team used an “implicit

association” test to record, for example, whether volunteers associated pictures of the base with positive words such as “joy” or negative ones such as “pain”.

When polled a week later, many who were undecided about the base in the first poll had resolved to support or oppose it – and the team found that their decision could be predicted by their responses on the association test (Science, vol 321, p 1100).

Though not a perfect science, such testing may be of interest to pollsters looking to improve their election forecasts.

TOO HEAVY ON THE METALSDo Ayurvedic medicines cure or cause harm? That’s the question raised by a study showing that 21 per cent of 193 traditional Indian Ayurvedic medicines bought on the internet from US or Indian sources contained high amounts of lead, mercury or arsenic.

One sample of a preparation called Ekangvir Ras had 26,000 parts per million of lead. This compares with a US legal limit of 2 ppm in pharmaceutically produced calcium tablets for the elderly.

In a subset of preparations called Rasa Shastra medicines, minerals with heavy metals are deliberately added. “Ayurvedic practitioners think that if these are mixed properly, they are non-toxic, but that conflicts head-on with conventional scientific thinking,” says Robert Saper of Boston University School of Medicine (Journal of the American

Medical Association, vol 300, p 915).Saper wants regulators to limit the

heavy metals in all food supplements.

BATS FACE EXPLOSIVE PROBLEM

“These abnormal vocalisations

in mice can be likened to

children with autism”

“Beware: exploding lungs” is not a sign you would expect to see near a wind turbine, but it could explain why bats are dropping dead around the machines.

The risk that turbines pose to birds has long dogged the debate over wind energy. Now it seems bats face a greater risk, though why, as they can echolocate moving objects, has remained a mystery.

One theory was that high-frequency noise from the gears and blades disrupted their echolocation systems.Erin Baerwald of the University of Calgary, Canada, and colleagues examined 188 dead bats from wind farms across southern Alberta to see if this was true. They found that 90 per cent had signs of internal haemorrhaging, but only half showed signs of direct contact with the turbine blades (Current

Biology, vol 18, p R695).

Baerwald suggests that vortices which form around the tip of a moving blade create a region of low air pressure, and that when bats fly into this area their delicate lungs suddenly expand, bursting the blood vessels and killing the bat. As birds’ lungs are more rigid, and therefore more resistant to sudden changes in pressure, the team think they do not suffer the same fate.

Bats eat agricultural pests, so if wind turbines affect their numbers local ecosystems could be damaged. The effects might be global: “The species being killed are migrants,” says Baerwald. “If bats are killed in Canada that could have consequences for ecosystems as far away as Mexico.” One solution could be to raise the minimum wind speed needed to set the blades in motion since most bats are more active in relatively calm conditions.

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–Weapons of bat destruction?–

Autistic mice Voting slip

4 | NewScientist | 30 August 2008 www.newscientist.com