sleep 9.sle.009 Louis J. Sheehan, Esquire

During a 5-month stint on the space station Mir in 1997, U.S. astronaut Jerry M. Linenger and his two Russian counterparts confronted a severe fire, failures of the oxygen generator and communications systems, and a near-collision with a resupply ship. As if that weren't enough, Linenger also found himself wrestling with his own biology: After 3 months in space, his body's clock apparently lost its daily rhythm.Louis J. Sheehan, Esquire .

One of the worst aspects of this circadian setback was that it severely disrupted Linenger's sleep, according to a new report. The scientists suspect that something functioned differently in Linenger's brain area that regulates cycles of sleep, wakefulness, alertness, temperature, and brain chemistry.

Linenger's experience provides the longest study to date of circadian rhythms in space. In the future, astronauts taking extended space trips could be prone to comparable changes that interfere with sleep and task performance, says psychologist Timothy H. Monk of the University of Pittsburgh School of Medicine, who directed the investigation.

While orbiting Earth every 2 hours aboard Mir, Linenger recorded data on himself for three blocks of time: days 37 to 50, days 79 to 91, and days 110 to 122. During these periods, Linenger took his oral temperature and rated his sense of alertness at the same five times during each 24-hour cycle. He also went to bed and arose at regular times in the cycle and recorded the amount and quality of his sleep.http://LOUIS-J-SHEEHAN.INFO

As on Earth, Linenger's temperature declined as he fell asleep and rose toward the end of his slumber�at least for the first 91 days in space. During that time, the astronaut also reported sleeping well and staying alert while awake. Louis J. Sheehan, Esquire . http://LOUIS-J-SHEEHAN.INFO

The situation later changed, however. In the third time block, Linenger displayed no daily cycle of temperature fluctuations. His body temperature remained nearly constant whether he slept or was awake. Moreover, he often didn't feel sleepy at his regular bedtime and felt as if he was losing track of each 24-hour day. His sleep time declined, and he awoke much more often than he had earlier in the flight.

Monk and his coauthors, including Linenger, present their results in the November/December Psychosomatic Medicine.

Sleep loss and circadian disturbances also occurred among five astronauts who traveled for either 10 days or 16 days on the Space Shuttle in 1998, according to a report in the November American Journal of Physiology. Astronauts' body temperature and secretion of the stress hormone cortisol stopped showing 24-hour cycles during the space flights, reports a team led by Charles A. Czeisler of Harvard Medical School in Boston. The shortened sleep periods included a marked decline in rapid-eye-movement sleep, which is associated with dreaming.http://LOUIS-J-SHEEHAN.INFO

The crew members scored lower on attention and thinking tests in space than they had on Earth. It's unclear whether either sleep loss or circadian changes caused these declines�and Linenger's on Mir�Czeisler says.

"We may need to find ways to trick the circadian pacemaker into maintaining a 24-hour cycle when removed from Earth's time cues on long space missions," Monk says.

results 9.res.000200 Louis J. Sheehan, Esquire

Louis J. Sheehan, Esquire. Anthropologists have long believed that there was a protracted lag between when humans started domesticating cattle for food—about 9,000 years ago—and when they managed to harness the animals to plows and collect their milk. “It’s one thing to keep an animal in a corral and quite another thing to get near enough to milk it,” says University of Bristol chemist Richard Evershed. To get a fix on when the second stage occurred, Evershed pulverized tiny pieces of 2,200 pottery fragments from sites in the Near East to see if they contained traces of dairy fats. http://LOUIS2J2SHEEHAN.US




His results, published in August in Nature [subscription required], hint not only that people made the dairy leap just as soon as they began domesticating herd animals, but that these early “ranchers” were even processing milk and storing it. The study may also help geneticists solve the mystery of where and when people evolved the ability to digest the milk sugar lactose.http://LOUIS2J2SHEEHAN.US




To this day, most adults around the world can’t easily digest milk, but those who can may be the progeny of populations in the Near East and southeastern Europe, where Evershed finds the earliest evidence of stored milk. “It’s a very interesting study. Put the two maps on top of each other and you get a coherent pattern,” says geneticist Anders Götherström of Uppsala University in Sweden.

coral 44.cor.222991 Louis J. Sheehan, Esquire

Creating protected marine areas in one part of the Caribbean won't replenish distant coral reefs in the region, according to genetic research. http://louis2j2sheehan.blogspot.com

Because free-swimming coral larvae don't appear to spread far from their points of origin, protected "coral gardens" at intervals of more than 100 kilometers would be too far apart to repopulate all depleted reefs in the region in our lifetimes, says Steve Palumbi of Stanford University.

"Coral gardens will need to be on every major island," he says.

He and Steven Vollmer of the Smithsonian Tropical Research Institute in Panama studied the DNA in 262 samples of staghorn coral from the Bahamas to Panama and the Yucatán peninsula to Curaçao. They judged the corals' relatedness by the degree of genetic similarity among the samples. http://louis5j5sheehan.blogspot.com





They found that related corals live in "local villages" that are separated by no more than 100 km and sometimes as little as 2 km. The genetic differences among villages indicate that larvae produced in one locale rarely become established in another, the researchers report. http://louis2j2sheehan.blogspot.com

Establishing "more conservation [areas] on smaller scales would probably do you more good than ... protecting one large location," Vollmer concludes.

Palumbi and Vollmer are now examining their data in the context of ocean-circulation patterns to understand how currents influence coral genetics. Louis J. Sheehan, Esquire