December 15, 2006, 4:51 AM CT

Scientists Make Liquid Crystal Discovery

What do milk, paint, ink and liquid crystals have in common? Colloids. Findings of Kent State University researchers indicate that manipulating the size of colloids, micron-sized or nanometer-sized particles, can produce huge changes in the material properties of liquid crystals.

In a recently published article in the scholarly journal Physical Review Letters, the researchers illustrate that when the concentration and size of the colloids and liquid crystals are properly tuned, the systems formed promise a new technique for synthesizing liquid crystals with specific molecular properties. The ferroelectric nanoparticles have a significant impact on the material properties of the liquid crystal host; meanwhile they are stable in the liquid crystals and invisible to naked eye.

Manipulation of these systems also leads to reduction in the amount of power mandatory to run liquid crystal displays, such as computer screens, and could result in creation of a range of different liquid crystal materials for a wide variety of applications.........

Posted by: Sarah      Permalink         Source

December 13, 2006, 7:06 PM CT

Tobacco Prevention Ads May Backfire

Tobacco company-sponsored anti-smoking advertising aimed at youths not only has no negative effect on teen smoking, it may actually encourage youngsters to smoke, according to a study co-authored by an Oregon State University researcher.

Results from the study also show that tobacco industry-sponsored prevention ads aimed at parents often have harmful effects on students, also increasing their likelihood of smoking.

"We suspected this the minute we saw the kind of ads the tobacco companies were creating," said Brian Flay, a professor in the Department of Public Health at Oregon State University. "Their objective is to get customers, not to stop customers from finding them".

The study appears in the recent issue of American Journal of Public Health.

Flay was one of nine researchers from Bridging the Gap, a policy research program based at the University of Illinois at Chicago and the University of Michigan, who worked on this study, which is the first to examine how youth are affected by parent-targeted ads sponsored by the tobacco industry.

More than 100,000 students from all areas of the country in 8th, 10th and 12th grades were surveyed to assess the relationship between exposure to tobacco company prevention advertising and youth smoking-related beliefs, intentions and behaviors. Researchers linked these data with Nielsen Media Research data on the exposure of youth to smoking-related ads that appeared on network and cable stations in the 75 largest United States media markets from 1999 to 2002.........

Posted by: Sean      Permalink         Source

December 13, 2006, 6:27 PM CT

Soil Nutrition And Carbon Sequestration

USDA Forest Service (FS) scientists from the FS Southern Research Station (SRS) unit in Research Triangle Park, NC, along with colleagues from Duke University, published two papers in The Proceedings of the National Academy of Science (PNAS) that provide a more precise understanding of how forests respond to increasing atmospheric concentrations of carbon dioxide (CO2), the major greenhouse gas driving climate change.

Building on preliminary studies reported in Nature, the researchers found that trees can only increase wood growth from elevated CO2 if there is enough leaf area to support that growth. Leaf area, in turn, is limited by soil nutrition; without adequate soil nutrition, trees respond to elevated CO2 by transferring carbon below ground, then recycling it back to the atmospheric through respiration.

"With sufficient soil nutrition, forests increase their ability to tie up, or sequester carbon in woody biomass under increasing atmospheric CO2 concentrations," says Kurt Johnsen, SRS researcher involved in the project. "With lower soil nutrition, forests still sequester carbon, but cannot take full advantage increasing CO2 levels. Due to land use history, many forests are deficient in soil nutrition, but forest management -- including fertilizing with nitrogen -- can greatly increase growth rate and wood growth responses to elevated atmospheric CO2".........

Posted by: Tyler      Permalink         Source

December 13, 2006, 4:30 AM CT

Tall Mountains on Titan

The infrared-sensitive camera on NASA's Cassini spacecraft has photographed the tallest mountains ever seen on Saturn's moon, Titan.

The mountain chain is nearly a mile high (1.5 kilometers), 93 miles long (150 kilometers) and 19 miles wide (30 kilometers). The mountains are topped by bright, white material which may be methane or other organic (carbon-containing) "snow".

"We see a massive mountain range that reminds me of the Sierra Nevada in the western United States," said Cassini scientist Robert H. Brown of the University of Arizona Lunar and Planetary Laboratory in Tucson. Brown is head of Cassini's visual and infrared mapping spectrometer (VIMS), which imaged the mountains in Titan's southern hemisphere during the Oct. 25, 2006 flyby.

The camera took its highest-resolution infrared views of Titan ever during this flyby, resolving surface features as small as 400 meters, or about 440 yards. Other features seen in the high-resolution VIMS images include fields of dunes and a deposit that resembles a volcanic flow.

If Titan were Earth, the mountains would be at latitudes near New Zealand. They probably formed as mid-ocean ridges form on Earth: The surface crust pulls apart, and material beneath the crust wells up through the crack, creating a ridge.........

Posted by: Brooke      Permalink         Source

December 13, 2006, 4:24 AM CT

Some Snowflakes Can Look The Same

Snowflakes are one of the most recognizable and endearing symbols of winter. Their intricate shapes have been the inspiration for Christmas ornaments, jewelry and U.S. postage stamps. They are the subject of song, school projects and even scientific investigation, including a possible impact on global warming.

Jon Nelson, a researcher with Ritsumeikan University in Japan, has studied snowflakes for 15 years, and has some interesting insights into their delicate structures.

Is it true that no two snowflakes are alike?

The old adage that 'no two snowflakes are alike' may ring true for larger snowflakes, but it might not hold true for smaller, simpler crystals that fall before they've had a chance to fully develop. Regardless, snow crystals have tremendous diversity, partly due to their very high sensitivity to tiny temperature changes as they fall through the clouds.

How do snowflakes form?

A snowflake starts as a dust grain floating in a cloud. Water vapor in the air sticks to the dust grain and the resulting droplet turns directly into ice. And that's where the science kicks in.

First, the tiny ice crystal becomes hexagonal (six-sided). This shape originates from the chemistry of the water molecule, which consists of two hydrogen atoms bonded to an oxygen atom. Because of the angle of the water molecule and its hydrogen-bonding, the water molecules in a snowflake chemically bond to each other to form the six-sided flake. The flake eventually sprouts six tiny branches. Each of these branches grows to form side branches in a direction and shape that are influenced by the clustering of water molecules on the ice crystal surfaces.........

Posted by: Sarah      Permalink         Source

December 12, 2006, 5:08 AM CT

It Gives Much More To Quitting Than Exercise

A study of more than 36,000 women by researchers from the Universities of Minnesota and Pennsylvania found that a high level of physical activity in women who smoked reduced their risk of developing lung cancer by nearly three quarters, compared with smokers who did no exercise.

Published in the recent issue of Cancer Epidemiology Biomarkers & Prevention, the study also found 'moderate' activity among smokers was associated with a 65 per cent risk reduction, and lower relative risks were also seen in former smokers who had moderate or high activity levels.

However, the researchers pointed out that despite seeing benefits in exercise, the absolute risk of developing lung cancer is still very large in current and former smokers regardless of activity level.

The study's lead author, Kathryn Schmitz, an assistant professor at the University of Pennsylvania, explained: "Smokers who exercise are at a 35 per cent lower risk of developing lung cancer relative to smokers who don't exercise, but if you smoke at all, your risk of developing lung cancer is 10- to 11- fold higher than if you didn't smoke".

"The most important thing a smoker can do to reduce risk is to quit smoking. That said, exercising and being active can offer a marginal change in risk," she added.........

Posted by: Sean      Permalink         Source

December 12, 2006, 4:56 AM CT

Excavating Site Around First Baptist Church

Providence's First Baptist Church is the oldest Baptist church in America - but how was the area and its grounds used before The Meeting House was built in 1775? A group of Brown University students enrolled in Anthropology 160 are investigating that question while learning archaeological techniques, as they excavate the property surrounding this historical site.

Students at Brown University are conducting an archaeological dig on the property surrounding the First Baptist Church in Providence, at the invitation of the congregation. In addition to providing undergraduate students an opportunity to participate in hands-on archaeological research and excavation training without leaving campus, the project may document an important part of city history.

The excavations are part of Anthropology 160, sponsored by Brown University's Anthropology Department and the Artemis A.W. and Martha Sharp Joukowsky Institute for Archaeology and the Ancient World. The field directors are Zachary Nelson, a postdoctoral research associate in anthropology, and Katherine Marino, a doctoral candidate at the Joukowsky Institute.

"Archaeological practice can not be wholly described with words," Nelson said. "There is a necessary experiential element to archaeological work that can only be achieved through actual practice".........

Posted by: William      Permalink         Source

December 11, 2006, 9:36 PM CT

Plant One Tree And Save The Earth

Can planting a tree stop the sea level from rising, the ice caps from melting and hurricanes from intensifying?

A new study says that it depends on where the trees are planted. It cautions that new forests in mid- to high-latitude locations could actually create a net warming. It also confirms the notion that planting more trees in tropical rainforests could help slow global warming worldwide.

In the first study to investigate the combined climate and carbon-cycle effects of large-scale deforestation in a fully interactive three-dimensional climate-carbon model, researchers from Lawrence Livermore National Laboratory, Carnegie Institution and Universite Montpellier II observed that global forests actually produce a net warming of the planet.

The study provides a holistic view of the deforestation issue. "This is the first comprehensive assessment of the deforestation problem" said Govindasamy Bala, lead author of the research that will be presented on Dec. 15 at the American Geophysical Society annual meeting in San Francisco.

The models calculated the carbon/climate interactions and took into account the physical climate effect and the partitioning of the carbon dioxide release from deforestation among land, atmosphere and ocean.

Forests affect climate in three different ways: they absorb the greenhouse gas carbon dioxide from the atmosphere and help to keep the planet cool; they evaporate water to the atmosphere and increase cloudiness, which also helps keep the planet cool; and they are dark and absorb a lot of sunlight, warming the Earth. Climate change mitigation strategies that promote planting trees have taken only the first effect into account.........

Posted by: Tyler      Permalink         Source

December 11, 2006, 9:33 PM CT

Predicted Present Day Distribution Of Elusive First Stars

With the help of enormous computer simulations, astronomers have now shown that the first generation of stars -- which have never been observed by scientists -- should be distributed evenly throughout our galaxy, deepening the long-standing mystery about these missing stellar ancestors. The results are published in this week's issue of the Astrophysical Journal.

The problem is that despite years of looking, no one has ever found any of these stars. "Many astronomers thought this was because the stars without heavy elements were hidden from us," said Evan Scannapieco, first author and a postdoctoral fellow at the Kavli Institute for Theoretical Physics at the University of California, Santa Barbara. "Because our galaxy formed from the inside out, the idea was that these very old stars would all be near the center. But the center of Milky Way is extremely crowded with dust and newer stars, making it very hard to detect individual old stars in this environment".

This earliest generation of stars should look very different from later-forming stars like the Sun; yet so far, no one has detected a survivor from this primordial population. One of the long-standing explanations for this discrepancy was that these stars might all be contained in regions near the center of the Milky Way, where they are very hard to observe. The results of the new study make that explanation unlikely.........

Posted by: Brooke      Permalink         Source

December 11, 2006, 5:03 AM CT

Sea Urchin Genome Is a Biology Boon

Researchers have long known that humans and sea urchins are closely related. In fact, these animals are the only invertebrates on the human branch of the evolutionary tree of life. Now that the sea urchin genome is sequenced and assembled, that genetic connection is even clearer.

After identifying 23,300 genes made from 814 million letters of DNA code taken from Strongylocentrotus purpuratus, the California purple urchin, an international science team has observed that humans share 7,077 genes with urchins. This makes the spiny, spineless creature a closer genetic cousin to man than the fruit fly or worm, more widely studied model organisms. Results from the sequencing project are published in a special six-article section of Science.

Other surprises from the project: Urchins have the most sophisticated innate immune system of any animal studied to date. They carry genes linked to a number of human diseases, such as muscular dystrophy and Huntington's disease. The urchin also has genes linked to taste and smell, hearing and balance.

And these eyeless animals can see - or at least sense light. How? Through their feet. Researchers found genes linked to vision, genes that are activated in the urchin's tube feet, puny projections on the animal's shells that help it move and feed. "Nobody would've predicted that sea urchins have such a robust gene set for visual perception," said Gary Wessel, a Brown University biology professor and member of the Sea Urchin Genome Sequencing Consortium. "I've been looking at these organisms for 31 years - and now I know they were looking back at me".........

Posted by: Ashley      Permalink         Source