Every kilogram of predator needs a fixed amount of prey.

Every kilogram of meat-eating mammal needs 111 kilograms of prey to sustain it, say two ecologists. The rule holds from weasels to bears.

With many species of carnivore endangered, the discovery could help conservationists work out how to maintain a species’ resource base.

Chris Carbone, of the Institute of Zoology, London, and John Gittleman, of the University of Virginia, found the rule when they compare

Astronomers Dr Simon Jeffery of the Armagh Observatory and Dr Hideyuki Saio of Tohoku University, Japan, have finally solved a long-standing mystery concerning the creation of two particular kinds of rare stars. They have found that a class of variable stars named after their prototype R Coronae Borealis (RCrB), and a related group called `extreme helium stars` are the products of mergers between pairs of white dwarf stars. What kind of star results from the merger depends on the composition of the w

Two Basque companies, Enerlim and NECESA, have developed a new wind generator, a wind reservoir to make use of wind energy.

This wind reservoir is much lighter than ordinary three-arm wind generators; hence, it is more economical and easier to install. On the other side, the machine is completely modular, as columns, pulleys and plates can be divided in order to make easier the production, transport and installation. The largest piece to be transported and installed is 12 meters long and 2

Astronomers using the Gemini North Telescope on Hawaii’s Mauna Kea report that they have created a three-dimensional movie of a powerful, active galaxy located some 70 million light years away. The addition of a new instrument, the Integral Field Unit (IFU), to the Gemini telescope enabled the group to study light from the galaxy NGC1068 in much greater detail. From a single still of NGC1068, the IFU generated data on the physical conditions and velocities of galactic material throughout the image.

Scientists have developed a blood test that may reveal changes in the brain caused by Alzheimer’s disease. The technique, tested so far only in mice, predicts the amount of amyloid plaque (formed from clumps of proteins that kill surrounding cells) in an animal’s brain. The research, detailed in a report in the current issue of the journal Science, holds promise for the development of predictive methods to diagnose the disease years ahead of the onset of clinical symptoms.

David Holtzman of

Women with early breast cancer could avoid needless chemotherapy thanks to work carried out in Chicago on identifying biochemical markers which indicate whether or not cancer is likely to spread to other parts of the body, the 3rd European Breast Cancer Conference in Barcelona heard today (Saturday 23 March).

Ruth Heimann, Associate Professor in the department of radiation and cellular oncology at the University of Chicago, USA, said that patients with early breast cancer which has not sprea