News & Views in 1999

Much of human appreciation of the natural world — sky, sea and so on — stems from its slowly changing features. Daedalus now plans a slowly changing statue, the pose of which will drift subtly all the time. Instead of fading into the urban background, it will continue to surprise and delight the passer-by.

Spend all day peering down a microscope? Then you may well suffer from headaches and backaches. Some researchers have designed a workstation that straightens out the hunched posture that microscopists are usually forced to adopt, and that could ease the pain.

New and old satellite data are helping glaciologists understand some of the curious features on the Antarctic continent. Comparison of declassified data from the 1960s with modern satellite images has revealed great expanses of snow dunes that have apparently not moved in the past 30 years. Other high-resolution images have exposed the source of giant streams of ice that flow into the sea.

Game-playing computer programmes, such as that which beat chess champion Gary Kasparov in 1997, generally rely on the expertise of the programmer. An approach involving checker-playing neural networks instead allows the networks to evolve competitively. The best of them have beaten human players at the ‘expert’ level.

Type 2 diabetes arises when resistance to the glucose-lowering effects of insulin combines with impaired insulin secretion to raise the levels of glucose in the blood. Studies into the molecular basis of insulin resistance have focused on the peroxisome proliferator-activated receptor gamma (PPAR-gamma). Three patients with type 2 diabetes have been identified with loss-of-function mutations in thePPAR-gammagene, indicating that this protein is required for normal insulin sensitivity.

A study of colour perception shows that, when assigning colour to objects, the seeing brain takes into account subtle reflections of light between the surfaces in a scene.

Improving the sensitivity of photographic emulsions requires much chemical processing, which increases the risk of fogging. A new way of increasing emulsion sensitivity without introducing fog has the potential to improve high-speed films, which may suffer from poor image quality.

This week Daedalus further explores the consequences for citation indexes of Internet-based publication. He proposes a system involving publication of referees' comments along with a paper, and predicts the emergence of ‘citing regions’ — the biggest of which would be the domain of authoritative and consensual opinion.

The first bacterial glutamate receptor has been identified, and has an unexpected property: it is very selective for potassium ions. The receptor's amino-acid sequence shows similarity to both glutamate receptors and potassium channels, raising the exciting prospect that both originated from a common ancestor.

In many snakes, males have longer tails than females, a characteristic that seems to have arisen early in evolution. From studies of mating red-sided gartersnakes in Manitoba, Canada, it seems that male tail length correlates with copulation success, but the selective force for longer tails remains a matter of surmise.

Studies of phenomena called hotspots and superswells, evident at Earth's surface, offer the best clues as to the dynamic state of the underlying mantle. Their essential features have for the first time been reproduced in laboratory simulations of mantle convection scaled to Earth-like conditions.

The study of lifespan in worms has mainly evolved around the dauer-formation-2 gene (daf-2), which, when mutated, results in a dramatic extension of lifespan. A similar extension has now been observed in worms mutated in a range of genes that also affect the shape and function of sensory neurons. These results imply that sensory neurons can exert a strong effect on lifespan, and this link is thought to involve an insulin-signalling pathway.

Jan van Paradijs: high-energy astrophysicist who hunted big astronomical game.

The first completely sequenced plant chromosomes, from the mustard Arabidopsis thaliana, reveal a dynamic genome that is constantly being rearranged.

Astronomers have previously inferred the existence of giant extrasolar planets from the wobble they generate in their parent star. Now, the shadow caused by a planet passing in front of its star, and the probable detection of reflected light from a planet orbiting a very bright star, provide direct evidence for their existence. Such studies offer a way to probe the chemical composition and atmospheres of extrasolar planets.

It used to be thought that fish larvae, at the mercy of the currents, drifted vast distances through the open ocean. But two studies of reef fish show that a surprisingly high proportion of them never leave the waters in which they were spawned. This finding has implications for the management of marine ecosystems.

The neurodegeneration characteristic of transmissible spongiform encephalopathies is caused by changes in the metabolism of the prion protein (PrP^C). In most cases, PrP^C is converted to an abnormal protease-resistant form, PrP^Sc. But in some genetically inherited forms of the disease another abnormal form — ^CtmPrP — accumulates. A new study shows that CtmPrP may be a neurotoxic molecule that is common to both the genetic and acquired forms of prion diseases.