December 5, 2006, 5:09 AM CT

Can the Stanley Cup playoffs harm your hearing?

During last year's NHL playoffs, Edmonton Oilers' fans tried to earn the title of loudest arena in the game, but new University of Alberta research shows that even a few hours of exposure to that level of noise can be harmful.

Bill Hodgetts from the U of A's Faculty of Rehabilitation Medicine and Dr. Richard Liu, from the Faculty of Medicine and Dentistry measured the noise levels during games three, four and six during the Stanley Cup finals against the Carolina Hurricanes last year. Liu attended the games and wore a noise dosimeter near his ear every second of the entire game. No matter where he went in the building, the dosimeter would sample his noise exposure. The research is published in the current edition of the Canadian Medical Association Journal.

The researchers found that for the levels experienced in game three, it took less than six minutes to reach the maximum allowable daily noise dose. Or everyone at the game received approximately 8100 per cent of their daily noise dose without any hearing protection. "Given the vast numbers of fans that do not wear hearing protection to hockey games, thousands are at risk for hearing damage," said the researchers.

Most people don't consider the risk of excessive noise exposure when participating in leisure activities, say the researchers, even though such noise over a period of a few hours can be harmful. "The risk of hearing loss for those who attend hockey games frequentlyseason ticket holders, workers in the arena, hockey players themselveswarrants serious consideration," they write in the paper. Even the cheapest foam earplugs would make a difference.........

Posted by: Jim      Permalink         Source

December 5, 2006, 4:59 AM CT

Rise In California Temperatures

Increasing temperatures in California during the next 45 years could negatively affect the amount of almonds, walnuts, oranges, avocados and table grapes that Americans put on their tables.

As per new research in the journal Agricultural and Forest Meteorology, production losses in some of California's most popular crops could be as high as 40 percent by mid-century.

In the study, scientists from Lawrence Livermore National Laboratory reviewed the impact of climate change on six major perennial crops in California: wine grapes, almonds, table grapes, oranges, walnuts and avocados. Each of these crops is typically planted only once every 25-40 years. However, so that climate can change considerably in the lifetime of individual vines or trees.

Using more than 20 climate models, the authors assessed the response of these crops to projected changes in temperature (an increase of 2 degrees to 4 degrees Celsius) and precipitation.

"Climate change should be an important factor in selecting perennial varieties and deciding whether and where they should be planted in California," said David Lobell, the lead author of the paper who collaborated with researchers at the Carnegie Institution, Stanford University and UC Merced. "This study indicates that warmer temperatures will tend to reduce yields of these crops in their current locations."........

Posted by: Tyler      Permalink         Source

December 5, 2006, 4:38 AM CT

The art and science of sensors

A forest ranger helicopter flies over a forest, scattering sensors that can relay temperature data to the ranger station. To ensure minimal environmental impact with maximum robustness, the sensors are very simple: they are basically tiny, sturdy thermometers. After the sensors are scattered, they might be moved further by winds, rains, rivers, or even animals. Is there a way to take the local information sent by the sensor network and turn it into global information about the existence and location of fires in the forest" In particular, without knowing the exact locations of the sensors, can one nevertheless glean information about the coverage area of the sensor network".

As sensor technology has exploded, such fundamental questions have come to the forefront in a number of areas. In particular, national security measures increasingly depend on sensor technology to detect, for example, radiological or biological hazards, hidden mines and munitions, or specific individuals in a crowd. Mathematics, particularly the area of topology, provides a way of addressing such questions.

The January 2007 issue of the Notices of the AMS will carry the article "Homological Sensor Networks" by Vin de Silva and Robert Ghrist. The article describes new results by the authors, which demonstrate how homology theory provides fundamental insights useful in analyzing sensor networks.........

Posted by: Kevin      Permalink         Source

December 4, 2006, 5:01 AM CT

From Light to Sodium Atoms

For the first time, tornado-like rotational motions have been transferred from light to atoms in a controlled way at the National Institute of Standards and Technology (NIST). The new quantum physics technique can be used to manipulate Bose-Einstein condensates (BECs), a state of matter of worldwide research interest, and possibly used in quantum information systems, an emerging computing and communications technology of potentially great power.

As published in the Oct. 27 issue of Physical Review Letters,* the research team transferred orbital angular momentum-essentially the same motion as air molecules in a tornado or a planet revolving around a star-from laser light to sodium atoms.

The NIST experiment completes the scientific toolkit for complete control of the state of an atom, which now includes the internal, translational, and rotational behavior. The rotational motion of light previously has been used to rotate particles, but this new work marks the first time the motion has been transferred to atoms in discrete, measurable units, or quanta. Other researchers, as well as the NIST group, previously have transferred linear momentum and spin angular momentum (an internal magnetic state) from light to atoms.

The experiments were performed with more than a million sodium atoms confined in a magnetic trap. The atoms were chilled to near absolute zero and in identical quantum states, the condition known as a Bose-Einstein condensate in which they behave like a single "super-atom" with a jelly-like consistency. The BEC was illuminated from opposite sides by two laser beams, one of them with a rotating doughnut shape. Each atom absorbed one photon (the fundamental particle of light) from the doughnut laser beam and emitted one photon in the path of the other laser beam, picking up the difference in orbital angular momentum between the two photons. The interaction of the two opposing lasers created a corkscrew-like interference pattern, inducing the BEC to rotate-picture a rotating doughnut, or a vortex similar to a hurricane.........

Posted by: Sarah      Permalink         Source

December 3, 2006, 9:06 PM CT

Beyond the bonds that bind

Scientists at the University of California, Santa Barbara have shown that, under the right circumstances, hydrogen can form multicenter bonds, where one hydrogen atom simultaneously bonds to as a number of as four or six other atoms. Tested for hydrogen in metal oxides, the discovery could have a broad range of technological impact. The research is available today in the advance online publication of Nature Materials.

Professor Chris G. Van de Walle and Project Scientist Anderson Janotti, both of the Materials Department of the College of Engineering at UC Santa Barbara, have shown that multi-coordinated hydrogen is a likely explanation for electronic conductivity in metal oxides. Metal oxides are widely used in everything from sunscreen to sensors.

Hydrogen, the simplest of the elements (consisting of one proton and one electron) is typically expected to exhibit simple chemistry when forming molecules or solids. Hydrogen atoms almost always form a single bond to just one other atom, leading to a two-center bond with two electrons. Exceptions to the rule are rare; there are only a few cases when hydrogen bonds simultaneously to two other atoms, forming a three-center bond.

Hydrogen can replace an oxygen atom and form a multicenter bond with adjacent metal atoms. For example, in ZnO, hydrogen equally bonds to the four surrounding Zn atoms, becoming fourfold coordinated. These multicenter bonds are highly stable and explain previously puzzling variations in conductivity as a function of temperature and oxygen pressure. The results suggest that hydrogen can be used as a substitutional dopant in oxides, a concept that is counterintuitive and should be of wide interest to researchers.........

Posted by: Sarah      Permalink         Source

December 3, 2006, 8:42 PM CT

Measuring Very Short Laser Pulses

Researchers have perfected a technique for very accurately measuring and controlling the electromagnetic waves within some of the shortest laser pulses ever made, says new research published recently. Being able to fully understand and control these laser pulses represents an important step towards using them to track and manipulate electrons in leading-edge research at the sub-atomic level.

The study, published in Nature Physics, focused on extremely short laser pulses, less than 10 femtoseconds long - a femtosecond is one million-billionth of a second. These laser pulses can allow researchers to move and control the electrons in atoms and molecules, and to understand, for example, how molecules are formed. To achieve this reliably, the pulse of electromagnetic waves emitted from the laser must be controlled and measured with a precision which, until now, has been very hard to achieve.

The team of physicists from Imperial College London attained an unprecedented level of accurate measurement by firing the femtosecond laser pulse into a sample of gas, which responds by emitting an x-ray pulse which is even shorter in duration - up to 10 times shorter than the original laser pulse. The scientists observed that the spectrum of the x-ray pulse has encoded within it all the information necessary to precisely reconstruct the waveform of the original laser pulse. Through careful measurements and some 'intelligent' software designed specifically for this purpose, the scientists were therefore able, for the first time, to measure the waveform of individual femtosecond pulses.........

Posted by: Kevin      Permalink         Source

December 1, 2006, 5:07 AM CT

Theory Of Oscillations May Explain Biological Mysteries

New mathematical studies of the interactions between oscillating biological populations may shed light on some of the toughest questions in ecology, including the number and types of species in an ecosystem, as per an article in the December 2006 issue of BioScience. The article, by John Vandermeer of the University of Michigan, shows how extensions of established theory suggest that a number of animal and plant populations oscillate in synchrony because of interactions such as predation and competition. Such synchronization can have far-reaching effects. Vandermeer suggests that several well-known biological conundrums, such as the higher-than-expected diversity of plankton in aquatic ecosystems, may be explained this way.

Physicists know that even a weak coupling between oscillating systems can yield synchronized oscillations, a phenomenon that was studied with pendulums by the seventeenth century Dutch mathematician Christiaan Huygens. Biologists have only in recent years started to explore the implications for their subject. But it is already clear that coupled oscillating biological populations can give rise to potentially important effects such as synchronized chaos: the interaction between two weakly competing consumers of a food resource can be transformed by the arrival of a third competitor to provide unpredictable opportunities for the newcomer to invade. Vandermeer holds out hopes that the study of oscillations in biological populations will lead to insights into complex systems, such as those that include animals that eat other predators as well as omnivores that eat both predators and those predators prey.........

Posted by: Kevin      Permalink         Source

December 1, 2006, 4:47 AM CT

Weight Training Intensity And Growth Hormone Levels

A study published in the recent issue of the American Journal of Physiology-Endocrinology and Metabolism looked at different forms of growth hormone, used different testing methods, and varied weight training regimens. The research found that the role of growth hormone in women's muscle development may be more complicated than previously thought.

"We found that growth hormone was responsive to moderate and heavy exercise regimens having 3-12 repetitions with varying weight loading," said the study's principal author, William J. Kraemer. "Women need to have heavy loading cycle or workout in their resistance training routines, as it helps to build muscle and bone".

The study, "Chronic resistance training in women potentiates growth hormone in vivo bioactivity: characterization of molecular mass variants," was carried out by Kraemer, Jeff S. Volek, Barry A. Spiering and Carl M. Maresh of the University of Connecticut, Storrs; Bradley C. Nindl, U.S Army Research Institute of Environmental Medicine, Natick, Mass.; James O. Marx, The University of Pennsylvania, Philadelphia; Lincoln A. Gotshalk, University of Hawaii at Hilo; Jill A. Bush, University of Houston, Texas; and Jill R. Welsch, Andrea M. Mastro and Wesley C. Hymer, The Pennsylvania State University, University Park, Penn. The The American Physiological Society published the study.........

Posted by: Sean      Permalink         Source

December 1, 2006, 4:27 AM CT

Seagrass ecosystems at a 'global crisis'

An international team of researchers is calling for a targeted global conservation effort to preserve seagrasses and their ecological services for the worlds coastal ecosystems, as per an article reported in the recent issue of Bioscience, the journal of the American Institute of Biological Sciences (AIBS).

The article "A Global Crisis for Seagrass Ecosystems" cites the critical role seagrasses play in coastal systems and how costal development, population growth and the resulting increase of nutrient and sediment pollution have contributed to large-scale losses worldwide.

"Seagrasses are the coal mine canaries of coastal ecosystems," said co-author Dr. William Dennison of the University of Maryland Center for Environmental Science. "The fate of seagrasses can provide resource managers advance signs of deteriorating ecological conditions caused by poor water quality and pollution."

Among its findings, the study analyzed an apparent disconnect between the scientific communitys concerns over seagrass habitat and its coverage in the popular media. While recent studies rank seagrass as one of the most valuable habitat in coastal systems, media coverage of other habitats including salt marshes, mangroves and coral reefs receive 3 to 100-fold more media attention than seagrass systems.........

Posted by: Jessica      Permalink         Source

December 1, 2006, 4:23 AM CT

Potential For Biodiversity Management

While global protected areas, including nature reserves, parks, and areas protected by treaties, protect some aspects of biodiversity, shortcomings remain: the areas only cover certain habitats and local people often resent their formal management. Natural sacred sites exist in many countries around the world, with communities often sharing and managing sites that are not under formal protection. Such sites cover a wide variety of habitats and are often located in biodiversity hotspots. Shonil Bhagwat (Natural History Museum, London and University of Oxford) and Claudia Rutte (University of Bern, Switzerland) propose that such habitats should be included in biodiversity management.

Although 23 percent of Earth's tropical forests are formally protected, only 8 percent of cropland and natural vegetation mosaic habitats receive the same protection. Natural sacred sites, protected by local traditions, are often situated within agricultural landscapes, providing corridors for wildlife. These sites come in many forms, including burial grounds and sites of ancestral deity worship, and often include organisms not protected in more formal settings. For example, sacred groves in the Koduga district of Karnataka state, India, have relict populations of certain threatened tree species that are not found in formal protected areas.........

Posted by: Tyler      Permalink         Source