theoretically...

Genes beat experience in determining your brainpower late in life, according to studies of Swedish twins by British scientists. A team led by Robert Plomin of the Institute of Psychiatry in London studied pairs of identical and fraternal twins aged over 80 in Sweden. (Identical twins have identical genes, while fraternal twins have only half their genes in common.) Even at that age, 62 per cent of the twins' cognitive abilities - such as spatial ability or memory - could be attributed to genetic influences, which is roughly the same percentage as for adolescents. The results appeared in the journal Science.

Ice on the Moon? It seems not, according to radar studies. Last November, hopes were raised that there might be a huge frozen lake covering up to 135 square kilometres at the Moon's south pole.

Such a theory was based on interpretations of data from the Clementine spacecraft. The presence of such a lake, in turn, would make it much easier to establish a permanent station on our satellite - rather than shipping oxygen out there on a rocket, it could be extracted from the water by solar-powered electrolysis.

However, observations made by the Arecibo Observatory in Puerto Rico suggest that what Nasa's excitable scientists interpreted as ice is actually just the rough surfaces of asteroid impact craters. "There is still the possibility that there are ice deposits in the bottom of deep craters," added one researcher. It looks like they'll just have to go and look properly.

US scientists have discovered a bacterium in sewer sludge that "breathes in" toxins from polluted groundwater and gives back a harmless gas. Known as coccoid Strain 195, the bacterium was isolated from sludge at a sewage treatment plant in Ithaca, New York, built in the days when toxic dry- cleaning solvents and industrial degreasing agents were simply flushed down the drain. Strain 195 breaks down two specific pollutants - tetrachloroethene and trichloroethene, both thought to be carcinogens - into non-toxic ethene. More studies are planned. "I'd like to know what kind of diet it likes," said one researcher. "It's used to having a lot of other organisms around it. The more we purified it, the harder it was to grow because it didn't have its friends around."

With another Earth Summit approaching, the World Bank last week urged the world's richest countries to provide about pounds 7.5m to help finance the phase-out of production of chlorofluorocarbons (CFCs) in Russia by 2000. Though domestic production was meant to have stopped in 1996, Russia - a major black-market source of CFCs - said it couldn't meet the deadline because it was too costly to replace the CFCs, which are used as coolants. CFCs destroy the ozone layer, increasing the amount of ultraviolet reaching Earth and heightening the risk of skin cancers. According to United Nations figures, Russia produced about 18,000 tonnes of CFCs in 1996. Developing countries have until 2010 to phase out their use.

The "science vs creationism" trial in Australia ended in an effective defeat for Australian geologist Ian Plimer last week after the judge dismissed his main complaint against a fundamentalist, Allen Roberts, who claimed to have found scientific evidence of the remains of Noah's Ark. The judge rejected the complaint of Plimer and his American co-applicant David Fasold that Roberts had acted in trade or commerce and illegally misled those who had financially backed him. But he did uphold a claim of copyright infringement against Roberts. Afterwards, Roberts claimed the verdict "preserved free speech" while Plimer argued that it had been inhibited. Plimer may be bankrupted by the legal costs of losing the action.