Published: Sunday 31 July 2005

sleepless babies: Newborn dolphins and killer whales don't sleep for a whole month after birth, says a study by a team led by Jerome Siegel of the University of California at Los Angeles, US. The mothers also stay awake over the period to keep a close eye on their offspring.

The observation is surprising given that other animals, such as rats, die if forcibly denied sleep. And in humans, as any new parent will vouch, sleep deprivation is a form of torture.

cancer alarm: Biologists at the University of California, Berkeley, have found damage to a cell's DNA triggers a chain reaction that causes increased expression of a marker recognised by the body's immune system. The study sheds light on a long-standing question of how the natural killer cells -- which attack tumours -- differentiate cancerous cells from healthy ones.

According to the study's lead author Stephan Gasser, cancer cells present a special challenge because they are still the body's own cells, albeit ones gone awry.

apple a day: A Canadian study claims red delicious may be the most beneficial variety of apples because it contains higher levels of antioxidants. The study led by Rong Tsao of Agriculture and Agri-Food Canada in Guelph, Ontario, measured the antioxidant activity of the skins of eight popular apple varieties.

Antioxidants help neutralise reactive molecules called free radicals, which have been linked to heart disease, cancer and Alzheimer's disease.

misplaced gene?: For the first time, a plant gene has been found in an animal. Matthias Habetha and Thomas Bosch of the University of Kiel, Germany chanced upon the gene in Hydra, a small aquatic organism. They were studying the symbiosis -- intimate living together for mutual benefit -- between Hydra and an algae, Chlorella. The algae provide photosynthetic energy to the Hydra in return for a safe place to live.

rail risk: Global warming and the resulting high temperatures may pose a threat to the world's highest railway, part of which has tracks laid on frozen ground. The US $3.16 billion railway project, linking China's Qinghai province with Tibet, is due to become operational next year. "By 2050, safe operation of the railway will be affected if temperatures keep rising, as observed over the past decades," says Luo Yong, deputy director of China's National Climate Centre. Temperatures on the plateau may climb by 3.4C by 2050, he adds.

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