October 26, 2006, 4:51 AM CT

Nuclear Receptors In Bee Genome

Susan Fahrbach, a Wake Forest University biologist, is among the more than 170 researchers who helped decode the honey bee genome. She contributed to the article on the bee genome sequence that appears in the Oct. 26 issue of Nature.

Her piece of the puzzle -- analyzing the nuclear hormone receptors found in the bee genome -- also appears in the current issue of Insect Molecular Biology.

The honey bee was chosen to have its genome sequenced because of its dual importance to agriculture and medicine. The well-known pollination activities of honey bees add billions of dollars of value to U.S. crops every year, but bees are also used in the laboratory to study issues related to human health such as immunity, longevity and diseases of the X chromosome. In addition, brain scientists are interested in the honey bee's complex social life and their ability to communicate the location of flowers to other members of the hive.

Fahrbach, Reynolds Professor of Developmental Neuroscience, and her co-researchers at Wake Forest and the University of Illinois, searched the genome sequence to find all of the nuclear receptors encoded in the bee genome. They found that the same nuclear receptors that control the development of the nervous system during the early.........

Posted by: Ashley      Permalink         Source

October 26, 2006, 4:46 AM CT

World's Most Intense Thunderstorms

A summer thunderstorm often provides much-needed rainfall and heat wave relief, but others bring large hail, destructive winds, and tornadoes. Now with the help of NASA satellite data, researchers are gaining insight into the distribution of such storms around much of the world.

By using data from the NASA Tropical Rainfall Measuring Mission (TRMM) satellite, scientists identified the regions on Earth that experience the most intense thunderstorms. Their study was reported in the August 2006 issue of the Bulletin of the American Meteorological Society. The strongest storms were found to occur east of the Andes Mountains in Argentina, where warm, humid air often collides with cooler, drier air, similar to storms that form east of the Rockies in the United States. Surprisingly, some semi-arid regions have powerful storms, including the southern fringes of the Sahara, northern Australia, and parts of the Indian subcontinent. In contrast, rainy areas such as western Amazonia and Southeast Asia experience frequent storms, but relatively few are severe. Northern Pakistan, Bangladesh, and parts of Central Africa also experience intense thunderstorms.

"TRMM has given us the ability to extend local knowledge about storms to a near-global reach," said lead author Edward Zipser, University of Utah, Salt Lake City. "In addition to containing the only precipitation radar in space, TRMM's other instruments provide a powerful overlap of data that is extremely useful for studying storms".........

Posted by: Tyler      Permalink         Source

October 24, 2006, 8:51 PM CT

Early Bronze Age Mortuary Complex Discovered

An ancient, untouched Syrian tomb that wowed the archaeological world on its discovery by Johns Hopkins University scientists nearly six years ago has revealed another secret: It is not alone.

The tomb, which was filled with human and animal remains, gold and silver treasures and unbroken artifacts dating back to the third millennium B.C., is actually one of at least eight located near each other in Umm el-Marra, archaeologist Glenn Schwartz said. That northern Syrian city is thought to bethe site of ancient Tuba, one of Syria's first cities and the capital of a small kingdom, said Schwartz, the Whiting Professor of Archaeology in the Department of Near Eastern studies at Johns Hopkins.

The newly discovered tombs contain signs of the ritual sacrifice of humans and animals, including the skeletons of infants and decapitated donkeys, as well as puppy bones, Schwartz said. "Given these discoveries, it's likely that the tomb complex is a royal cemetery," he said.

"Animal sacrifices were certainly a big part of this culture in that offerings of sheep and other animals are given to the gods to eat and also given to deceased royal ancestors," Schwartz said. He and his team have dubbed this site the Acropolis Center mortuary complex.

The tombs are located about 35 miles east of the site of Aleppo, the main city and dominant center in the region dating at least as far back as 2000 B.C., Schwartz said. Though the tomb complex is much less showy than the famous one from the same period at Ur in Mesopotamia, which is now Iraq, the Umm el-Marra complex is the only known one in Syria from this time period.........

Posted by: William      Permalink         Source

October 24, 2006, 8:43 PM CT

A Supersolid Not Quite So Super?

A deceptively simple experiment, recently reported in the journal Science, has moved physics one step closer to explaining the odd behavior of supersolid helium. The unusual state of matter - in which a portion of the atoms are able to flow through a solid crystal with no resistance - was predicted as early as 1969 but not observed until recently.

In 2004, Eunsong Kim and Moses Chan from Penn State University published the first experimental evidence that the predicted behavior could actually be demonstrated in the laboratory. In the last two years, a flurry of papers attempted to clarify under what conditions the behavior emerges. So when Humphrey Maris, a professor of physics at Brown University, visited colleagues Satoshi Sasaki and Sebastien Balibar at l'Ecole Normale Superieure in Paris, they decided they needed to plan an experiment that could shed some new light on the problem.

"We were trying to think of an easy way to do something on superfluid solids," said Maris. "The idea of something flowing through something solid is pretty weird, isn't it? That's what we like about it".

Maris and company hatched an elegant plan that uses kitchen table physics to examine the behavior of this strange new state of matter. To understand how they probed the phenomenon, try this simple experiment. Fill a drinking straw with water and cover it with your finger. Place it in a glass of water. As long as your finger seals the straw, the water won't flow out into the cup. As soon as you release your finger, it does. The water doesn't flow out of the straw until you open a path that allows air to replace it.........

Posted by: Sarah      Permalink         Source

October 24, 2006, 8:23 PM CT

Soot from wood stoves impacts global warming

New measurements of soot produced by traditional cook stoves used in developing countries suggest that these stoves emit more harmful smoke particles and could have a much greater impact on global climate change than previously thought, as per a research studyscheduled to appear in the Nov. 1 issue of the American Chemical Society journal Environmental Science & Technology.

Perhaps as a number of as 400 million of these stoves, fueled by wood or crop residue, are used daily for cooking and heating by more than 2 billion people worldwide, as per the study's lead authors, Tami Bond, Ph.D., and doctoral candidate Chris Roden of the University of Illinois, Urbana-Champaign. In a field test in Honduras, the scientists observed that cook stoves there, which are similar to those used in other developing nations, produce two times more smoke particles than expected, based on prior laboratory studies. These dark, sooty particles, which are darker than those produced by grassland or forest fires, have a climate warming effect because they absorb solar energy and heat the atmosphere, as per Roden.

In earlier work, Bond estimated that burning firewood -- the principal fuel for cook stoves in the developing world -- produces 800,000 metric tons of soot worldwide each year. In comparison, diesel cars and trucks generate about 890,000 metric tons of soot annually. These two sources each account for about 10 percent of the soot emitted into the world's atmosphere each year, she said.........

Posted by: Tyler      Permalink         Source

October 24, 2006, 8:18 PM CT

Amazon River Reversed Flow

Ask any South American dinosaur which way the Amazon River flows and she would have told you east-to-west, the opposite of today. That's the surprising conclusion of scientists studying ancient mineral grains buried in the Amazon Basin.

The once westward roll of what is now the world's largest river was caused by a long-gone highland near what today is the river's mouth. That highland was created by the breaking away of South America from Africa and the creation of the Atlantic Ocean during the Cretaceous Period, 65 to 145 million years ago. Later, when the Andes rose up on the western side of South America, the river had no choice but to drain into the new ocean.

"It just happened in a way that the current Amazon could take advantage of where an old river and ocean basin used to sit," said geologist Russell Mapes, a doctoral candidate at the University of North Carolina in Chapel Hill.

Prior Brazilian and U.S. scientists have proposed smaller scale reversals and splits in the Amazon Basin, but nothing on the scale of the entire basin, said Mapes.

The evidence for the Amazon's ancient switcheroo comes in the form of tiny crystals of a mineral called zircon, as well as telltale signs of the river flow direction captured in the structure of old river sediments.........

Posted by: William      Permalink         Source

October 24, 2006, 7:26 PM CT

New Theory For Mass Extinctions

A new theory on just what causes Earth's worst mass extinctions may help settle the endless scientific dust-up on the matter. Whether you favor meteor impacts, volcanic eruptions, cosmic rays, epidemics, or some other cause for the worst mass extinction events in Earth's history, no single cause has ever satisfied all researchers all the time for any extinction event. That may be because big extinctions aren't simple events.

The new Press/Pulse theory gets around the controversy by rejecting the all-or-nothing approach to mass extinction, calling instead on a combination of deadly sudden catastrophes - "pulses" - with longer, steadier pressures on species - "presses".

"What we wanted to do is move away from the idiosyncratic approach to extinction mechanisms and look for what these intervals had in common. If you have A and B you will get a mass extinction," said Ian West, a 2006 graduate of Hobart and William Smith Colleges in Geneva, NY.

West and Hobart and William Colleges paleontology professor Nan Crystal Arens are scheduled to present their work on the Press/Pulse theory on Wednesday, 25 October, at the Annual Meeting of the Geological Society of America in Philadelphia.

Using databases that chart genera of marine organisms and their extinctions through the fossil record, West and Arens divided the last 488 million years of geologic history into four groups: times of suspected impact events (Pulses), times of massive volcanic eruptions (Presses), times when neither Presses nor Pulses occurred, and times when Press and Pulse coincided. They compared average extinction rates in geologic stages in each of these groups.........

Posted by: William      Permalink         Source

October 24, 2006, 7:11 PM CT

Trotting With Emus To Walk With Dinosaurs

One way to make sense of 165-million-year-old dino tracks may be to hang out with emus, say paleontologists studying thousands of dinosaur footprints at the Red Gulch Dinosaur Tracksite in northern Wyoming. Because they are about the same size, walk on two legs and have similar feet, emus turn out to be the best modern version of the enigmatic reptiles that once trotted along a long-lost coastline in the Middle Jurassic.

"We don't have any documented dinosaur bones and teeth from that period in North America, except for some very scrappy material from Mexico," said Brent Breithaupt, curator and director of the University of Wyoming's Geological Museum in Laramie, Wyo. That makes it very hard to connect the tracks to a particular dinosaur. And of course, "We unfortunately can't go out and see walking dinosaurs today. Or can we?".

After scouring the dinosaur fossil record in other parts of the world and deciding that a human-sized, meat-eating dinosaur (theropod) fit the bill for the tracks at Red Gulch, Breithaupt and his colleagues and students did something unusual. Instead of speculating about what the dinosaurs were doing, they went hunting for a modern analog animal they could study to help decipher the tracks.

Large flightless birds are the most logical choice and are, along with all birds today, thought to be descended from dinosaurs. But not all of those alive today are good choices or easy to work with. Ostriches are two-toed and have an attitude problem, so that ruled them out, says Breithaupt. Rheas have three toes, but are "like working with a bunch of kindergarteners on too much sugar," he said.........

Posted by: William      Permalink         Source

October 24, 2006, 5:55 PM CT

Predicting Risk for Recurrent Stroke

People who have just suffered their first ischemic stroke, a blood clot in the brain, often have elevated inflammatory biomarkers in their blood that indicate their likelihood of having another stroke or an increased risk of dying, according to Columbia University Medical Center researchers at NewYork-Presbyterian Hospital.

Published in the Oct. 23 Archives of Internal Medicine, results of the new study indicate that these inflammatory markers are associated with long-term prognosis after a first stroke, and may help guide clinical care for people who have suffered a first stroke.

A biomarker called lipoprotein-associated phospholipase A2 (Lp-PLA2), which has been FDA-approved to predict the risk of first stroke, was found to be a strong predictor of recurrent stroke risk. Researchers also found that elevated levels of another biomarker called high-sensitivity C-reactive protein (hs-CRP), a test commonly used to predict risk of heart disease, was associated with more severe strokes and an increased risk of mortality.

"A better understanding of biomarkers for stroke risk may lead to the use of prophylactic treatments to reduce risk of people suffering debilitating strokes," said lead author Mitchell S. V. Elkind, M.D., M.S., associate professor of Neurology at Columbia University College of Physicians and Surgeons and neurologist at NewYork-Presbyterian. "For example, statins appear to lower these biomarker levels, so our next step may be to study the clinical benefit of prescribing statins to reduce the risk of stroke in people with elevated biomarkers, and also to treat people who have suffered a stroke so that they do not have another serious event".........

Posted by: Sean      Permalink         Source

October 22, 2006, 11:29 PM CT

Strange Bacteria Thriving Two Miles Underground

A Princeton-led research group has discovered an isolated community of bacteria nearly two miles underground that derives all of its energy from the decay of radioactive rocks rather than from sunlight. According to members of the team, the finding suggests life might exist in similarly extreme conditions even on other worlds.

The self-sustaining bacterial community, which thrives in nutrient-rich groundwater found near a South African gold mine, has been isolated from the Earth's surface for several million years. It represents the first group of microbes known to depend exclusively on geologically produced hydrogen and sulfur compounds for nourishment. The extreme conditions under which the bacteria live bear a resemblance to those of early Earth, potentially offering insights into the nature of organisms that lived long before our planet had an oxygen atmosphere.

The scientists, who hail from nine collaborating institutions, had to burrow 2.8 kilometers beneath our world's surface to find these unusual microbes, leading the scientists to their speculations that life could exist in similar circumstances elsewhere in the solar system.

"What really gets my juices flowing is the possibility of life below the surface of Mars," said Tullis Onstott, a Princeton University professor of geosciences and leader of the research team. "These bacteria have been cut off from the surface of the Earth for many millions of years, but have thrived in conditions most organisms would consider to be inhospitable to life. Could these bacterial communities sustain themselves no matter what happened on the surface? If so, it raises the possibility that organisms could survive even on planets whose surfaces have long since become lifeless".........

Posted by: Ashley      Permalink         Source