Testosterone

People with a social anxiety disorder have a tendency to avoid looking at the person they are speaking to. A group of Dutch psychologists, including Anita Harrewijn and Philip Spinhoven from Leiden, demonstrate a test to that end in the science journal Psychoneuroendocrinology. They already knew that people with social anxieties have a lower level of testosterone and that testosterone influences they way they look at people in certain forms of that disorder.

The psychologists invited women with an anxiety disorder to visit them twice. On the first visit, the women were given a placebo while the second time they received a glass of testosterone. Then they were asked to look at faces on a screen: angry faces, happy faces and faces with a neutral expression.

Normally, a person with an anxiety disorder will look away quickly if an angry face appears on the screen, but after a dose of testosterone they spent as long looking at the angry faces as they did at the neutral faces. The authors suggest that the hormone may help in therapy.

Ditch water

Leiden environmental scientists claim that the effect of agricultural pesticides on creatures in the surrounding ditches is quite small. In Basic and Applied Ecology, they describe how, for two years, they took samples from the ditches along tulip fields and pastures, and compared the composition to samples from nearby ponds in wildlife areas. There were substantial differences in the numbers of small fish, insects and other beasties in the samples, but that is always the case when two biological samples are compared.

Using statistics, the researchers tried to clarify which differences were actually due to the pesticides. In the end, it emerged that the environmental factors had twice as much influence as pesticides while the influence of time is about the same.

Pulsar

The LOFAR radio telescope has discovered an odd pulsar and pulsars are quite odd as it is: collapsed stars with a massive density that spin round their axes like lighthouses, emitting beams of radiation. From a distance, the stars seem to be blinking – we only see the beam when it shines our way – and that’s why they’re called pulsating stars.

In the specialist astronomer’s journal MNRAS, a LOFAR team, including Laura Bîrzan and Huub Röttgering from Leiden Observatory, describe a pulsar with a “quiet mode”. The prosaically named star PSR B0823+26 has periods in which its beam is suddenly a hundred times weaker than normal.

We know of some 2,300 pulsars, but only a few seem to do that and we don’t quite know why. Other pulsars are the same age, the same weight and magnetic but don’t display the same behaviour.

By Bart Braun