March 28, 2007, 10:00 PM CT

Thinning of West Antarctic Ice

Polar ice experts from Europe and the United States, meeting to pursue greater scientific consensus over the fate of the world's largest fresh water reservoir, the West Antarctic Ice Sheet, conclude their three-day meeting at The University of Texas at Austin's Jackson School of Geosciences with the following statement:

Surprisingly rapid changes are occurring in the Amundsen Sea Embayment, a Texas-size region of the Antarctic Ice Sheet facing the southern Pacific Ocean. Experts across a wide range of scientific disciplines from the United States and United Kingdom met in Austin, Texas, to identify barriers to improved predictions of future sea-level rise resulting from these changes.

The United Nations Intergovernmental Panel on Climate Change (IPCC) reported in February that the scientific community could not provide a best estimate or an upper limit on the rate of sea-level rise in coming centuries because of a lack of understanding of the flow of the large ice sheets.

All of the ice on Earth contains enough water to raise sea level over 200 feet, with about 20 feet from Greenland and almost all of the rest from Antarctica. Although complete loss of the Antarctic Ice Sheet is not expected, even a small change would matter to coastal populations......... Posted by: Beverly      Read more         Source

March 27, 2007, 8:17 PM CT

A Mathematical Solution for Another Dimension

Ever since 1887, when Norwegian mathematician Sophus Lie discovered the mathematical group called E8, scientists have been trying to understand the extraordinarily complex object described by a numerical matrix of more than 400,000 rows and columns.

Now, an international team of experts using powerful computers and programming techniques has mapped E8--a feat numerically akin to the mapping of the human genome--allowing for breakthroughs in a wide range of problems in geometry, number theory and the physics of string theory.

"Eventhough mapping the human genome was of fundamental importance in biology, it doesn't instantly give you a miracle drug or a cure for cancer" said mathematician Jeffrey Adams, project leader and mathematics professor at the University of Maryland. "This research is similar: it is critical basic research, but its implications may not become known for a number of years".

Team member David Vogan, a professor of mathematics at the Massachusetts Institute of Technology (MIT), presented the findings today at MIT.

The effort to map E8 is part of a larger project to map out all of the Lie groups--mathematical descriptions of symmetry for continuous objects like cones, spheres and their higher-dimensional counterparts. A number of of the groups are well understood; E8 is the most complex......... Posted by: Beverly      Read more         Source

March 27, 2007, 7:10 PM CT

Black Carbon Transported from Asia

More than three-quarters of the particulate pollution known as black carbon and transported at high altitudes over the West Coast during spring comes from Asia, according to a research team led by scientist V. Ramanathan of the Scripps Institution of Oceanography (SIO) in La Jolla, Calif. The material not only affects climate in Asia, it also carries consequences for the Pacific Ocean region that drives much of the climate around the world.

Climate scientists Ramanathan and Odelle Hadley are lead authors of a research paper appearing in the March 14 issue of the Journal of Geophysical Research. The research was funded by the National Science Foundation, the National Oceanic and Atmospheric Administration (NOAA) and the California Energy Commission (CEC).

"This study demonstrates that aerosols from all sources in East Asia significantly affect not only regional climate, but also affect climate across the 8,000 kilometers of the north Pacific Ocean," said Jay Fein, NSF program director for climate dynamics.

Transport of Asian black carbon, which is generated by automobile exhaust, agricultural burning and other sources, is heaviest in spring when cold Arctic fronts dip to lower latitudes and loft warmer air to higher altitudes. Worldwide transport of the aerosols keeps them at high altitudes for up to two weeks......... Posted by: Beverly      Read more         Source

March 25, 2007, 8:14 PM CT

Not All Nanomaterials Are Created Equal

Troy, N.Y. The size, type, and dispersion of nanomaterials could all play a role in how these materials impact human health and the environment, according to two groups of researchers at Rensselaer Polytechnic Institute. In new studies, the teams found that while carbon nanotubes inhibited growth in mammalian cells, they sustained the growth of commonly occurring bacteria.

The seemingly contradictory findings highlight the need for society to better grasp the impacts these infinitesimally small particles could have when released into the environment or the human body, the researchers said. Both results were presented at the 233rd American Chemical Society (ACS) National Meeting in Chicago, March 25-29, 2007.

In the first study, which was led by Assistant Professor of Biomedical Engineering Deanna M. Thompson, researchers examined the impact of carbon nanotubes on the growth of rat heart muscle cells to better understand how they affect mammalian cells and ultimately human tissue and organs. Unlike previous research that focused on the effects of nanotube clusters on cell growth, this study looked at both the impacts of clusters and related finely dispersed material composed of small bundles of nanotubes and other nanoparticulate impurities.

The researchers discovered that the finely dispersed material, despite its low concentration, inhibited animal cell growth more than larger clusters of nanotubes. Activated carbon, a commonly used nanoporous carbon material, had a lower impact on the cells than either the large aggregates or the finely dispersed material. The findings of this study were recently published in the journal Toxicology Letters......... Posted by: Beverly      Read more         Source

March 25, 2007, 6:59 PM CT

Excess nutrients or water limit biodiversity

Too much of a good thing (nutrients or water) actually decreases the diversity of species in an ecosystem while it increases the productivity of a few species, according to a grassland experiment conducted by University of Minnesota researchers.

The reduction in species diversity occurs because increasing the amounts of limiting resources, such as nitrogen and water, makes an ecosystem more homogeneous and consequently reduces the number of opportunities for competing species to coexist. Put another way, it reduces the number of niches, allowing a few species to dominate.

The study, conducted by David Tilman, Regents Professor of Ecology, and Stanley Harpole will be published March 25 in the online version of the journal Nature. Harpole, who is now a postdoctoral associate at the University of California, Irvine, was a graduate student at the University of Minnesota when the research was carried out.

"In essence, the data in the article strongly supports a new explanation for why the world contains so many species," said Tilman. "It shows that plant diversity is directly related to the number of limiting factors (such as soil moisture, nitrogen, phosphorous, potassium and water)".

It also helps explain why grasslands, lakes and rivers that are polluted with nitrogen and phosphorous (usually from agriculture) have fewer species. The reduction of species where the Mississippi River empties into the Gulf of Mexico is one of the best known examples of this phenomenon......... Posted by: Beverly      Read more         Source

Wed, 21 Mar 2007 03:03:25 GMT

Rare Butterflies Spotted Once Again After 30 Years in the Top End

After 30 years of disappearance, the rare butterflies of Australiaspotted once again in the Northern Territory. It is at the Garig Gunak Barlu National Park on the Cobourg Peninsula, lying on the north-east of Darwin, the northern Argus butterflies are found by the CSIRO.

This discovery proves outright the poor survey of many areas of the region. To add to, a very little is known of these rare butterflies here! The CSIRO also spotted white albatross and Asian tiger in the areas along with the butterflies.

Have the Indonesian species set up their breeding populations in the Top End? Entomologist Dr Michael Braby confirms on this.

Posted by: Irani      Read more     Source

March 19, 2007, 9:46 PM CT

How Computers and Electronics Work

Researchers have made an important advance in the emerging field of 'spintronics' that may one day usher in a new generation of smaller, smarter, faster computers, sensors and other devices, according to findings reported in today's issue of the journal Nature Nanotechnology.

The research field of 'spintronics' is concerned with using the 'spin' of an electron for storing, processing and communicating information.

The research team of electrical and computer engineers from the Virginia Commonwealth University's School of Engineering and the University of Cincinnati examined the 'spin' of electrons in organic nanowires, which are ultra-small structures made from organic materials. These structures have a diameter of 50 nanometers, which is 2,000 times smaller than the width of a human hair. The spin of an electron is a property that makes the electron act like a tiny magnet. This property can be used to encode information in electronic circuits, computers, and virtually every other electronic gadget.

"In order to store and process information, the spin of an electron must be relatively robust. The most important property that determines the robustness of spin is the so-called 'spin relaxation time,' which is the time it takes for the spin to 'relax.' When spin relaxes, the information encoded in it is lost. Therefore, we want the spin relaxation time to be as long as possible," said corresponding author Supriyo Bandyopadhyay, Ph.D., a professor in the Department of Electrical and Computer Engineering at the VCU School of Engineering......... Posted by: Beverly      Read more         Source

March 13, 2007, 9:23 PM CT

Vanishing Neurons Of Adolescence

Researchers at the University of Illinois have found that adolescence is a time of remodeling in the prefrontal cortex, a brain structure dedicated to higher functions such as planning and social behaviors.

The study of rats found that both males and females lose neurons in the ventral prefrontal cortex between adolescence and adulthood, with females losing about 13 percent more neurons in this brain region than males.

This is the first study to demonstrate that the number of neurons in the prefrontal cortex decreases during adolescence. It is also the first to document sex differences in the number of neurons in the PFC. The study appears in the Feb. 9 issue of the journal Neuroscience.

Earlier studies in humans have found gradual reductions in the volume of the prefrontal cortex from adolescence to adulthood, said psychology professor and principal investigator Janice M. Juraska. "But the finding that neurons are actually dying is completely new. This indicates that the brain reorganizes in a very fundamental way in adolescence".

Juraska, graduate student Julie Markham and undergraduate student John Morris found that the number of neurons decreased in the ventral, but not dorsal, prefrontal cortex during adolescence. The number of glial cells, which surround and support the neurons, remained stable in the ventral PFC and increased in the dorsal PFC......... Posted by: Beverly      Read more         Source

March 8, 2007, 7:59 AM CT

Exploring Earth's Deepest Sinkhole

Scientists return this week to the world's deepest known sinkhole, Cenote Zacaton in Mexico, to resume tests of a NASA-funded robot called DEPTHX, designed to survey and explore for life in one of Earth's most extreme regions and potentially in outer space.

If all goes well with this second round of testing and exploration, the team will return in May for a full-scale exploration of the Zacaton system.

Sinking more than 1,000 feet, Zacaton has only been partially mapped and its true depth remains unknown.

During eight years of research, doctoral student Marcus Gary and hydrogeology professor Jack Sharp from The University of Texas at Austin's Jackson School of Geosciences discovered the system's unusual hydrothermal nature is analogous to liquid oceans under the icy surface of Jupiter's moon Europa.

Technology developed to explore the sinkholes could be applied to future space probes of Europa, where scientists believe that deep cracks and holes in the ice offer a chance of finding extraterrestrial life.

The technology could also be used to explore Earth's ice-bound polar lakes, which hold clues to the origins of life on Earth.

Microbes which appear to be new to science have been discovered floating in deep water and lining rocks in Zacaton. Far below sunlight's ability to penetrate, they may get their energy from nutrients welling up from hot springs. Gary and others speculate that previously undocumented life may await discovery in the murky depths......... Posted by: Beverly      Read more         Source

March 5, 2007, 8:50 PM CT

New Coating Is Virtual Black Hole

Scientists have created an anti-reflective coating that allows light to travel through it, but lets almost none bounce off its surface. At least 10 times more effective than the coating on sunglasses or computer monitors, the material, which is made of silica nanorods, may be used to channel light into solar cells or allow more photons to surge through the surface of a light-emitting diode (LED).

Publishing in the March 1, 2007, Nature Photonics, lead author Jong Kyu Kim and a team from Rensselaer Polytechnic Institute in Troy, N.Y., reveal how they crafted the coating, which reflects almost as little light as do molecules of air.

Guided by National Science Foundation-supported electrical engineer Fred Schubert, the scientists developed a process based on an already common method for depositing layers of silica, the building block of quartz, onto computer chips and other surfaces.

The method grows ranks of nanoscale rods that lie at the same angle. That degree of the angle is determined by temperature. Under a microscope, the films look like tiny slices of shag carpet.

By laying down multiple layers, each at a different angle, the scientists created thin films that are uniquely capable of controlling light. With the right layers in the right configuration, the scientists believe they can even create a film that will reflect no light at all......... Posted by: Beverly      Read more         Source