October 29, 2006, 7:46 PM CT

Untold Stories Of Elk Skeleton

Seeing the well-preserved antlers, skull and partial skeleton of a very large elk that was found in northern Wisconsin was impressive enough. But what really intrigued Jean Hudson was what was found nearby - a Clovis point, a type of spearhead used by hunters from about 10,000 years ago.

Very few have been found this far north, and this spearhead may be the one that doomed the animal all those millennia ago, says Hudson, an associate professor of anthropology. Or the two specimens could be completely unrelated, she says.

If the two are linked, it would mean that the elk remains are particularly rare. More physical evidence of animals such as mastodons, wooly mammoths and giant bison exists than that of elk, says Hudson.

But decoding the secrets of an animal skeleton requires asking the same questions you would at a crime scene investigation: What were the time, cause and circumstances of death? It also involves sometimes getting it wrong, leading to new questions.

A swimmer discovered the antlers of what appears to be a prehistoric elk at the bottom of Middle Eau Claire Lake in Barnes, Wis., last summer. Matt McKay of the Department of Natural Resources in Hayward, who is assigned to the maintenance of the Clam Lake elk herd, estimated the elk would have been between 1,000 and 1,100 pounds when it was alive.........

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October 29, 2006, 6:59 PM CT

Lighter And Cheaper Alloys

Car engines that consume less energy and can keep running on low oil, lead-free plumbing fixtures, and tanks that are light enough to be airlifted, but are just as rugged as the much heavier varieties.

They sound futuristic, but these products are already realities thanks to materials that stretch the limits of performance. Called cast metal matrix composites (MMCs), they are cheaper, lighter and stronger than their original alloys. In fact, an aluminum-based MMC developed at the University of Wisconsin-Milwaukee (UWM) can replace iron-based alloys.

"These composites have many applications in the transportation, small engines, aerospace and computer industries," says Pradeep Rohatgi, a Wisconsin Distinguished Professor of Engineering who pioneered cost-effective methods of manufacturing these composites.

Now more than a 100-million-a-year industry themselves, MMCs have been used in components for train brakes, thermal management devices in computers, and even the space shuttle and the Hubble Space Telescope.

MMCs are engineered by combining metal with a totally different class of material, such as ceramics and recycled waste. Incorporating the two materials the matrix and the reinforcement materials result in amazing structural and physical properties not available in the natural world.........

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October 29, 2006, 6:53 PM CT

Flight of the Bumblebee

Rebecca Flanagan has probably come as close as a human can to reading the mind of a bumblebee.

Flanagan, a graduate student in biological sciences, and Associate Professor Jeffrey Karron are studying the behaviors of bees as they gather pollen - which plant species the bees forage on, which flowers they probe and in what order, and how many blooms they visit before moving on to another plant. In doing so, the bees make plant reproduction possible by dispersing pollen.

To predict where each bee that she tracks will carry its pollen next, Flanagan has to literally think like one.

"Once they've learned a foraging style that's been successful, they are more likely to stick with it rather than invest time in learning something new," says Flanagan.

But why go to such lengths to map the flight of the bumblebee? It may seem random and inconsequential. But it is neither, says Karron.

The bees are pivotal players in determining which plant populations survive through successful reproduction. If scientists could better understand nature's decision-making process, then they could use the information to increase crop yields and to boost conservation of native plant communities.

Best bee practices

Because there are many bee behaviors, the task isn't simple, but with tedious scrutiny it is documentable.........

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October 27, 2006, 9:28 PM CT

Vitamin C and Water Healthy for Plastics, Too

Two new laboratory breakthroughs are poised to dramatically improve how plastics are made by assembling molecular chains more quickly and with less waste. Using such environmentally friendly substances as vitamin C or pure water, the two approaches present attractive alternatives to the common plastic manufacturing technique called free radical polymerization (FRP).

"The methods both present novel and complementary ways to dramatically improve efficiency, product control, and cost for the polymer industry," said Andy Lovinger, the National Science Foundation program director who oversees funds for the two projects. "Each of these approaches could have a very significant impact on polymer manufacturing".

Plastics are polymers, long, potentially complex, molecule chains crafted from an array of smaller chemical units. Using FRP, chemical engineers can create the right plastic for a range of applications, such as a specific trim for a car door or soft foam for a pillow.

For some plastics, the building-block molecules do not easily link together. To surmount this problem, scientists from Carnegie Mellon University in Pittsburgh, Pa., devised a process called atom transfer radical polymerization (ATRP), which provides creative ways to coax the chemical subunits into chains. However, this method comes with certain costs, such as the need for a copper catalyst that can become unwanted waste.........

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October 27, 2006, 9:23 PM CT

How Female Pronghorns Choose Mate?

When a female animal compares males to choose a mate, she can't order a laboratory genetic screen for each suitor. Instead, she has to rely on external cues that may indicate genetic quality. Until now, biologists have focused on elaborate ornaments, such as the peacock's tail, as cues that females might use.

The thorny problem has been to explain how the correlation between male genetic quality and ornament quality can be maintained. If an ornament gives a male a mating advantage, then evolution would rapidly move to the point where all males, regardless of genetic quality, have high-quality ornaments.

"Female mate choice is likely a very important evolutionary force that does much more than select for ornaments in a few species," said John Byers of the University of Idaho. "It may be universally important in maintaining population genetic quality".

In work supported by the National Science Foundation (NSF), Byers has shown that certain females can choose good genes in a species that does not have ornaments, such as the American pronghorn, an antelope-like mammal that evolved in North America. Byers has been studying pronghorn at the National Bison Range, a 30-square-mile National Wildlife Refuge in northwestern Montana, for 20 years, and recognizes all individual pronghorn in the population.........

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October 27, 2006, 9:20 PM CT

How Oceans Emit Sulfur Into Atmosphere

Scientists have discovered a bacterial "switch gene" in two groups of microscopic plankton common in the oceans. The gene helps determine whether certain marine plankton convert a sulfur compound to one that rises into the atmosphere, where it can affect the earth's temperature, or remain in the sea, where it can be used as a nutrient.

"This new gene offers a powerful tool to study the question of how these plankton are involved with sulfur exchange between the ocean and atmosphere," said Mary Ann Moran, marine microbial ecologist at the University of Georgia. Moran and her colleagues published their findings in the Oct. 26, 2006, issue of the journal Science.

Much of the sulfur in the atmosphere comes from the surface of oceans, from a compound called dimethlysulfide, or DMS. Marine plankton control how much sulfur rises into the atmosphere by converting a compound called DMSP, or dimethylsulfoniopropionate, to DMS or to sulfur compounds that are not climatically active. Moran and her team discovered a gene that controls whether or not these sea drifters create DMS that rises into the air.

"Isolating and discovering a novel, keystone bacterium from the ocean first, and then sequencing its genome enabled this team to find the genes involved in the DMSP cycle," said Matthew Kane, program director in the National Science Foundation (NSF) Division of Molecular and Cellular Biosciences, which supported the research. "The research has revealed the previously hidden role that marine microbes play in the global sulfur cycle".........

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October 27, 2006, 5:19 AM CT

What Killed Dinosaurs 65 Million Years Ago

Growing evidence shows that the dinosaurs and their contemporaries were not wiped out by the famed Chicxulub meteor impact alone, according to a paleontologist who says multiple meteor impacts, massive volcanism in India and climate changes culminated in the end of the Cretaceous Period.

The Chicxulub impact may have been the lesser and earlier of a series of meteor impacts and volcanic eruptions that pounded life on Earth for more than 500,000 years, say Princeton University paleontologist Gerta Keller and her collaborators Thierry Adatte from the University of Neuchatel, Switzerland, and Zsolt Berner and Doris Stueben from Karlsruhe University in Germany.

A final, much larger and still unidentified impact 65.5 million years ago appears to have been the last straw, said Keller, exterminating two-thirds of all species in one of the largest mass extinction events in the history of life. It's that impact - not Chicxulub - that left the famous extraterrestrial iridium layer found in rocks worldwide that marks the impact that finally ended the Age of Reptiles, Keller believes.

"The Chicxulub impact alone could not have caused the mass extinction," said Keller, "because this impact predates the mass extinction".

Keller is scheduled to present that evidence at the annual meeting of the Geological Society of America (GSA) in Philadelphia, on Tuesday, October 24, 2006.........

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October 27, 2006, 5:04 AM CT

Latest views of the V838

Hubble has returned to the intriguing V838 Monocerotis a number of times since its initial outburst in 2002 to follow the evolution of its light echo. Two new images provide the most astonishing views of V838 to date.

The unusual variable star V838 Monocerotis (V838 Mon) continues to puzzle astronomers. This previously inconspicuous star underwent an outburst early in 2002, during which it temporarily increased in brightness to become 600,000 times more luminous than our Sun. Light from this sudden eruption is illuminating the interstellar dust surrounding the star, producing the most spectacular "light echo" in the history of astronomy.

As light from the eruption propagates outward into the dust, it is scattered by the dust and travels to the Earth. The scattered light has travelled an extra distance compared to light that reaches Earth directly from the stellar outburst. Such a light echo is the optical analogue of the sound echo produced when an Alpine yodel is reflected from the surrounding mountainsides.

The NASA/ESA Hubble Space Telescope has been observing the V838 Mon light echo since 2002. Each new observation of the light echo reveals a new and unique "thin-section" through the interstellar dust around the star. This release shows new images of the light echo from the Hubble Advanced Camera for Surveys taken in November 2005 (left) and again in September 2006 (right). The numerous whorls and eddies in the interstellar dust are especially noticeable. Possibly they have been produced by the effects of magnetic fields in the space between the stars.........

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October 27, 2006, 4:45 AM CT

Gene Target Against Crohn's Disease And Ulcerative Colitis

The discovery by a six-member Inflammatory Bowel Disease (IBD) Genetics Consortium of a genetic risk factor for IBD has been reported in Science Express, the online publication of the journal Science. As per one of the Canadian principal investigators, director of the Laboratory in Genetics and Genomic Medicine of Inflammation at the Montreal Heart Institute, Dr. John D. Rioux, "This discovery may lead to a paradigm shift in our thinking from 'genetics of diseases to genetics of health', especially as concerns Crohn's Disease and Ulcerative Colitis." This discovery was, in part, due to the contributions of the gastroenterologists of the Quebec IBD Genetics Consortium led by Dr. Rioux and Dr. Alain Bitton of the McGill University Health Centre.

Inflammatory bowel disease, or IBD, describes two similar yet distinct conditions called Crohn's disease and ulcerative colitis. These diseases affect the digestive system and cause the intestinal tissue to become inflamed, form sores and bleed easily. Symptoms include abdominal pain, cramping, fatigue and diarrhea.

Crohn's disease may affect the gastrointestinal tract, from the mouth to the anus, and while Crohn's disease can not be cured by drugs or surgery, either may relieve symptoms.

In Canada, an estimated 170,000 Canadian men and women suffer from IBD, most frequently between the ages of 15-25, or 45-55. It is especially difficult for children and young adults since it often affects a person's self-concept. IBD is found throughout the world. However, it appears to be most common in North America and northern Europe; Canada having one of the highest incidence rates of IBD in the world. (1) In the U.S., more than 1 million Americans have Crohn's or colitis.........

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October 27, 2006, 4:40 AM CT

What Makes A Bee A He Or A She?

Three years ago, researchers pinpointed a gene called csd that determines gender in honey bees, and now a research team led by University of Michigan evolutionary biologist Jianzhi "George" Zhang has unraveled details of how the gene evolved. The new insights could prove useful in designing strategies for breeding honey bees, which are major pollinators of economically important crops-and notoriously tricky to breed.

The findings of Zhang and collaborators appear in a special issue of Genome Research devoted to the biology of the honey bee. The issue will be published online and in print Oct. 26, coinciding with the publication of the honey bee genome sequence in the journal Nature.

Researchers have long known that in bees-as well as wasps, ants, ticks, mites and some 20 percent of all animals-unfertilized eggs develop into males, while females typically result from fertilized eggs. But that's not the whole story, and the discovery in 2003 of csd (the complementary sex determination gene) helped fill in the blanks. The gene has a number of versions, or alleles. Males inherit a single copy of the gene; bees that inherit two copies, each a different version, become female. Bees that have the misfortune of inheriting two identical copies of csd develop into sterile males but are quickly eaten at the larval stage by female worker bees.........

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