The human internal clock fails to adapt to non-24-hour days and that fact takes its toll on astronauts, international travelers and shift workers. "Due to the shuttle orbit, astronauts often experience days that are less than 24 hours," says Dr. Kenneth Wright, with the National Space Biomedical Research Institute.

"Many experience sleep difficulties, averaging only about six hours of sleep a day." This can lead to increased risk of accidents due to fatigue and sleepiness, according to Wright. He evaluated how people's internal clocks were affected by exposure to 23.5-hour, 24-hour and 24.6-hour days. Shuttle missions typically operate on 23.5-hour days, and astronauts exploring Mars would experience a 24.65-hour day.

"Adapting to these different day lengths is critical to mission success," says Wright in the Proceedings of the National Academy of Science. Melatonin levels were evaluated to determine how participants adapted to the various day lengths. Light exposure is the strongest cue for the internal clock. "However, participants on the 24-hour day fixed work/rest schedule were able to maintain the appropriate melatonin cycles for sleep even in the dim light," Wright says. "Their internal clocks kept time with the day. The groups experiencing the shorter or longer days did not adapt."

OSCAR WINNERS DON'T LIVE LONGER

Oscar winning screenwriters have shorter lives than losing nominees, even though greater success is usually linked to better health, according to the British Medical Journal. Researchers in Canada identified all 850 screenwriters ever nominated for an academy award. On average, winners were more successful than nominees, as indicated by a 14 percent longer career, 34 percent more films, and 58 percent more four-star films. However, life expectancy was 3.6 years shorter for winners than for nominees, equivalent to a 37 percent relative increase in death rates. Additional awards were associated with a 22 percent relative increase in death rates, whereas a career with many nominations but no awards caused no significant increase in death rates. These results are not easily explained by talent, prestige, financial earnings, material conditions, or simple demographics, according to the researchers. They suggest that screenwriters are more apt to have unhealthy lifestyles e.g. more smoking, less exercise, frequent late nights with no sleep, unlike actors whose lives are under steady scrutiny. This may explain why Oscar winning actors and actresses live longer than nominees, and underscores the importance of behavior.

CHRISTMAS STAR'S TWIST

Christmas observations of a peculiar "twisting" star have provided a crucial insight into why the Sun's 11-year sunspot cycle is so unpredictable, according to European astronomers working at the Anglo-Australian Telescope in Australia. The star, AB Doradus, is best viewed over the festive period and for the last 10 years Andrew Collier Cameron, of St. Andrews University, has spent the holidays watching its starspots, New Scientist reports.

Like sunspots, starspots are created when magnetic fields break through a star's surface. But in the case of AB Doradus, 1000 times more of its surface is covered by spots than on our Sun. This is because AB Doradus is young and whizzes round about every 12 hours, creating a strong magnetic field. Stars are made of gas, and different latitudes of a star rotate at slightly different velocities. Analysis of Doppler shift effects in the spectrum from AB Doradus shows that the starspots appear in three main bands, each at different speeds.

With 10 years of data, Cameron thought he could pin down the velocity difference between the bands, but each year's records did not tally. "I came to the conclusion that the differential rotation was changing from one year to the next," he says. "Or the star was 'twisting' back and forth." This is the first direct evidence of something long been suspected -- that the magnetic field affects the gas flow inside the star, which generates the field in the first place, creating a feedback loop.

FISH SENSING POLLUTION CHANGE COLOR

Researchers in Singapore are developing a breed of fish capable of detecting water pollutants by changing color, Wired News reports. Scientists at the Department of Biological Sciences at Singapore's National University intend to produce commercially viable zebra fish as an alternative to current pollutant-testing systems. Zebra fish are usually black and silver in color, but through genetic manipulation researchers have produced a few varieties that radiate green or red fluorescent color. The researchers have isolated two types of gene promoters in the zebra fish -- an estrogen-inducible promoter and a stress-responsive promoter. These promoters -- the part of the gene that contains the information to turn the gene on or off -- have been used to drive the fluorescent color genes in transgenic zebra fish. A transgenic organism is one that contains genes from another species. According to researchers, such zebra fish will be able to respond to the presence of chemicals like estrogen, heavy metals and various toxins in water. "Compared to conventional chemical measurement, the live fish can tell us the biological effect of the pollutants," says project leader Zhiyuan Gong.

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