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Science
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Written by Staff Writer
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Jan 20, 2008 at 06:44 PM |
Astronomers have announced that a mystery object orbiting a star 170 light-years from Earth might have formed from the collision and merger of two protoplanets. The object, known as 2M1207B, has puzzled astronomers since its discovery because it seems to fall outside the spectrum of physical possibility. Its temperature, luminosity, age, and location do not match up with any theory. Studying 2M1207B is teaching astronomers about how to interpret data gathered from distant planetary objects, and may yield clues about what traits to look for when searching for habitable, extrasolar worlds.
"This is a strange enough object that it needs a strange explanation," said Eric Mamajek of the Harvard-Smithsonian Center for Astrophysics (CfA). The announcement was made in a press conference at the 211th meeting of the American Astronomical Society.
2M1207B orbits a 25-Jupiter-mass brown dwarf called 2M1207A seen in the direction of the constellation Centaurus. Computer models show that 2M1207A is very young, only about 8 million years old; therefore its companion should also be 8 million years old. At that age, it should have cooled to a temperature of less than 1300 degrees Fahrenheit (1000 Kelvin). However, observations show that 2M1207B is actually about 2400 degrees F (1600 K). The extra heat might be the result of a protoplanetary collision.
Right: This artist's concept shows a collision between two protoplanets, one the size of Jupiter and the other Neptune-sized. Astronomers believe that the unique object 2M1207B may have been created by a similar collision.
Credit: David A. Aguilar (Harvard-Smithsonian CfA)
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Last Updated ( Jan 20, 2008 at 06:55 PM )
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Written by Staff Writer
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Jan 20, 2008 at 06:08 PM |
Most people know it from experience: After so many hours of being awake, your brain feels unable to absorb any more-and several hours of sleep will refresh it.
Now new research from the University of Wisconsin School of Medicine and Public Health clarifies this phenomenon, supporting the idea that sleep plays a critical role in the brain's ability to change in response to its environment. This ability, called plasticity, is at the heart of learning.
Reporting in the Jan. 20, 2008, online version of Nature Neuroscience, the UW-Madison scientists showed by several measures that synapses - nerve cell connections central to brain plasticity - were very strong when rodents had been awake and weak when they had been asleep.
The new findings reinforce the UW-Madison researchers' highly-debated hypothesis about the role of sleep. They believe that people sleep so that their synapses can downsize and prepare for a new day and the next round of learning and synaptic strengthening. |
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Last Updated ( Jan 20, 2008 at 06:10 PM )
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Written by Staff Writer
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Nov 20, 2007 at 08:54 AM |
Environmental progress in France lags badly behind many of its neighbours such as Germany and Scandinavia. But Sarkozy has made improving the environmental credentials of France a major part of his election campaign this year. He has since created a superministry for ecology, biodiversity and sustainable development, with responsibility for the powerful sectors of transport, energy and construction — a first in France, where ecology was previously off the political radar
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Last Updated ( Nov 20, 2007 at 06:22 PM )
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Written by Staff Writer
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Nov 15, 2007 at 11:00 AM |
Perhaps it was one of those eureka moments, when the scientists realized they had discovered a new dinosaur with mouth parts designed to vacuum up food.
The 110 million-year-old plant eater, discovered in the Sahara Desert, was to be unveiled Thursday by the National Geographic Society.
Discoverer Paul Sereno named the elephant-sized animal Nigersaurus taqueti, an acknowledgment of the African country Niger and a French paleontologist, Philippe Taquet.
Sereno, a National Geographic explorer-in-residence and paleontologist at the University of Chicago, said the first evidence of Nigersaurus was found in the 1990s and now researchers have been able to reconstruct its skull and skeleton.
Nigersaurus may have looked like this (artist's impression)
While Nigersaurus' mouth is shaped like the wide intake slot of a vacuum, it has something lacking in most cleaners _ hundreds of tiny, sharp teeth to grind up its food.
The 30-foot-long Nigersaurus had a feather-light skull held close to the ground to graze like an ancient cow. Sereno described it as a younger cousin of the North American dinosaur Diplodicus.
Its broad muzzle contained more than 50 columns of teeth lined up tightly along the front edge of tis jaw. Behind each tooth more were lined up as replacements when one broke off.
Using CT scans the researchers were able study the inside of the animal's skull where the orientation of canals in the organ that helps keep balance disclosed the habitual low pose of the head, they reported.
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Written by Staff Writer
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Nov 15, 2007 at 07:42 AM |
A total of 1,030,911 cases of chlamydia were reported to the US in 2006, from 976.445 of 2005, and the real number of infections is probably on the order of 2.8 million, estimated Mr . Johnson Douglas and colleagues, of the national center for the prevention of HIV/SIDA, viral hepatitis, STD, and TB. Although there was substantial progress by preventing, while diagnosing, and by treating certain diseases in prior years, the CDC estimates that roughly 19 million STDs occur every year. Present among almost half young adults, the investigators wrote in the annual update book. The national rate of reported cases of Chlamydia in 2006 was 347.8 in 100.000, compared with 329.4 in 100.000, translating into an increase of 5.6%.
"The increases in reported cases and rates likely reflect the continued expansion of screening efforts and increased use of more sensitive diagnostic tests," the CDC investigators noted. "However, the continued increases may also reflect an actual increase in infections."
There were also significant racial disparities in chlamydia infections, with African Americans having a rate more than eight times higher than that of whites (1,275 per 100,000 versus 153.1 per 100,000). About 46% of all chlamydia cases in 2006 were reported among African Americans.
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