September 14, 2006, 4:30 AM CT

Warming climate might affect polar bear population

Some travel agencies touting Arctic tours have been revving up their recent promotions to tourists about the increased likelihood they will spot polar bears in this region where several populations of polar bears live. As per researchers from NASA and the Canadian Wildlife Service, these increased Arctic polar bear sightings are probably correlation to retreating sea ice triggered by climate warming and not due to population increases as some may believe.

The new research suggests that progressively earlier breakup of the Arctic sea ice, stimulated by climate warming, shortens the spring hunting season for female polar bears in Western Hudson Bay and is likely responsible for the continuing fall in the average weight of these bears. As females become lighter, their ability to reproduce and the survival of their young decline. Also, as the bears become thinner, they are more likely to push into human settlements for food, giving the impression that the population is increasing. The study will be published this week in the recent issue of the Journal Arctic.

Claire Parkinson, a scientist at NASA's Goddard Space Flight Center, Greenbelt, Md., and Ian Stirling, a senior scientist with the Canadian Wildlife Service, Edmonton, Alberta, used NASA satellite observations captured from 1979 to 2004 to show the reduction in sea ice cover in several specific areas where there are known polar bear populations. In most of the areas studied, they observed that ice break-up in these areas has been occurring progressively earlier.........

Posted by: Tyler      Permalink         Source

September 13, 2006, 9:57 PM CT

Viruses Switch Grip To Gain Upper Hand

Carbohydrates can be attractive, especially when they come packaged in candy bars or never-ending bowls of pasta.

Even viruses - those bits of occasionally harmful genetic material enclosed in shells of protein and fat - crave carbs. Except viruses aren't seeking a taste treat. They want to latch onto the carbohydrates that protrude from the surface of our cells and mount an invasion.

By changing which carbohydrates they attach to, viruses are able to infect cells more efficiently - a finding that may prove valuable to scientists seeking ways to fight cancer or brain diseases, say University of Florida researchers writing in the current Journal of Biological Chemistry. The discovery also helps explain how flu and other viruses are able to stay a step ahead of the body's own versatile immune system.

"If you think about the flu virus, a few simple amino acid changes can be the difference between a virus your body can defend against and one that will make you sick," said Mavis Agbandje-McKenna, Ph.D., an associate professor of biochemistry and molecular biology in the UF College of Medicine and senior author of the paper. "It seems structural juxtapositions of amino acids play a role in determining how viruses recognize cells and whether the viruses are harmful".........

Posted by: Sean      Permalink         Source

September 13, 2006, 9:52 PM CT

Arctic Sea Ice Diminishing Rapidly

The Arctic Ocean's perennial sea ice, which survives the summer melt season and remains year-round, shrank abruptly by 14 percent between 2004 and 2005, as per a newly published study. Scientists observed that the loss of perennial ice in the East Arctic Ocean, above Europe and Asia, neared 50 percent during that time as some of the ice moved to the West Arctic Ocean, above North America.

The overall decrease in winter Arctic perennial sea ice totaled 730,000 square kilometers [280,000 square miles]--an area the size of Texas. Perennial ice can be three meters [10 feet] thick, or more. It was replaced in the winter by new, seasonal ice, which was only about 0.3 to two meters [one to seven feet] thick and more vulnerable to summer melt. The research was published 7 September in the journal Geophysical Research Letters.

The decrease in perennial ice raises the possibility that Arctic sea ice will retreat to another record low extent this year. This follows four summers of very low ice-cover, as observed by active and passive microwave instruments.

A team of seven scientists, led by Son Nghiem of NASA's Jet Propulsion Laboratory in Pasadena, California, used satellite data to measure the extent and distribution of perennial and seasonal sea ice in the Arctic. While the total area of all Arctic sea ice was stable in winter, the distribution of seasonal and perennial sea ice changed significantly.........

Posted by: Tyler      Permalink         Source

September 13, 2006, 9:39 PM CT

Diabetics And Lower Limb Amputations

Many people suffering foot and leg pain falsely attribute their aches to temporary discomfort or simply "growing old," when something far more serious and often preventable is frequently taking place.

People that neglect foot and leg pain particularly the 20.8 million people in the U.S. with diabetes can be at risk for amputation. This neglect has contributed to a sharp rise in amputations, with the Centers for Disease Control finding the number of diabetes-related lower limb amputations to have increased by 227 percent between 1980 (33,000) and 2003 (75,000).

Diabetics are prone to amputation as the condition often causes blood vessels in the foot and leg to narrow, causing poor circulation. This makes diabetics susceptible to infection, making it difficult for these wounds to heal. In fact, nine out of 10 non-traumatic lower extremity amputations are instigated by an infection, according to a study led by Texas A&M University. The American Diabetes Association says that diabetes is the most frequent cause of non-traumatic lower limb amputations.

The unfortunate result of these trends is that each year, 75,000 people lose their foot, leg or toe due to diabetes, and 85 percent of these losses could have been avoided, according to the International Diabetes Federation.........

Posted by: Sean      Permalink         Source

September 13, 2006, 9:21 PM CT

Cellular Protein Factories

Proteins of all sizes and shapes do most of the work in living cells, and the DNA sequences in genes spell out the instructions for making those proteins. The crucial job of reading the genetic instructions and synthesizing the specified proteins is carried out by ribosomes, tiny protein factories humming away inside the cells of all living things.

Harry Noller, the Sinsheimer Professor of Molecular Biology at the University of California, Santa Cruz, has been studying the ribosome for more than 30 years. His main goal is to understand how the ribosome works and how it evolved, but there are also practical reasons to pursue this research. Many of the most effective antibiotics work by targeting bacterial ribosomes, and findings by Noller and others have led to the development of novel antibiotics that hold promise for use against germs that have developed resistance to current drugs. Drug-resistant staph infections, for example, are a serious problem in hospitals.

Noller's laboratory achieved breakthroughs in 1999 and 2001, producing the first high-resolution images of the molecular structure of a complete ribosome. Now, his team has made another major advance with an even higher-resolution image that enables them to construct an atom-by-atom model of the ribosome.........

Posted by: Ashley      Permalink         Source

September 13, 2006, 9:14 PM CT

Expedition to polar research

What better way to engage students in science than to apply lessons learned from fieldwork? This is the philosophy of Alaska teachers participating in the Arctic Expedition for K-12 Teachers, a program organized by the International Arctic Research Center (IARC) at the University of Alaska Fairbanks and a handful of international agencies.

For 33 days teachers from Alaska, Canada, France, Gera number of, Russia, Sweden and England will take atmospheric measurements, collect ice cores, install ice mass balance sensors and more, all under the guidance of an international team of polar researchers. Teachers and researchers will work together to collect data. Their work is based on the Kapitan Dranitsyn, an icebreaker currently cruising through the Arctic Ocean.

Todd Hindman, a teacher from Nome City School District, said This will give my students an opportunity to learn about the environment they live in, which will engage them in a meaningful way both inside and outside of the traditional classroom walls.

The experience will enhance my teaching by increasing my understanding of ocean systems, said Katie Turner, a science teacher at West Anchorage High School. It will give me real world experience and knowledge to share with my students.

The expedition advances researchers work in the fields of meteorology, biology, chemistry and oceanography. Five IARC researchers are aboard the Kapitan Dranitsyn, too, as part of the Nansen and Amundsen Basins Observational System (NABOS). Their aim is to better understand a flow of anomalous warm Atlantic water entering the Arctic Ocean. Preliminary data suggests this infusion of water from the Atlantic is increasing the temperature of the Arctic waters.........

Posted by: Tyler      Permalink         Source

September 13, 2006, 9:07 PM CT

Selective Sensors Based On Carbon Nanotubes

A team of scientists from Arizona State University and Motorola Labs, the applied research arm of Motorola Inc., has developed sensors based on carbon nanotubes, microscopically small structures that posses excellent electronic properties. In early tests, the new devices detected the presence of heavy metal ions in water down to parts per trillion levels.

Specifically, the scientists developed a method for applying peptides to single walled carbon nanotubes (SWNT) in field effect transistors.

"This is a fairly general sensor platform for all kinds of applications," said Nongjian Tao, an electrical engineering professor at Arizona State University and one of the scientists on the project. "We tested heavy metal ions in water, but the platform can be applied to a number of other areas to sense toxic chemicals in the air, or they can be used as biosensors when applied to medicine."

"Integration of nanosensors into devices and sensor networks will enable the detection of biological and chemical agents at very low concentrations, which could be vital in the areas of public safety and homeland security," added Vida Ilderem, vice president of the Embedded Systems Research Labs at Motorola, Tempe, Ariz.

The scientists report the advance in a paper, "Tuning the chemical selectivity of SWNT-FETs for detection of heavy metal ions," which would be reported in the journal Small. An early view of the article is available at the journal's web site (www3.interscience.wiley.com/cgi-bin/jissue/109627347).........

Posted by: Kevin      Permalink         Source

September 13, 2006, 5:11 AM CT

Do green markets actually lead to improvements in environmental quality?

Goods and services with environmental benefits are a growing part of many sectors of the economy, and a timely new paper from the current issue of the Journal of Political Economy analyzes how our willingness to pay more for environmentally friendly products actually influences environmental quality and social welfare. Surprisingly, the study finds that under certain reasonable conditions, green markets can actually discourage private support of public environmental entities.

Using a model of impure public goods, Matthew J. Kotchen (University of California, Santa Barbara) analyzes goods that have both private and public components, each of which is available individually. For example, shade-grown coffee is grown not on deforested plantations, but under the canopy of tropical forests. Thus, consumers are not only buying coffee, which is a traditional private good, but also biodiversity conservation. However, consumers also have the option to buy conventional coffee and donate directly to tropical conservation.

"Although green markets are promoted to improve environmental quality and promote social welfare, their actual effects may be detrimental to both," writes Kotchen. "These results, along with the conditions sufficient to rule them out, provide new insight into the potential advantages and disadvantages of green markets as a decentralized mechanism of environmental policy".........

Posted by: Ashley      Permalink         Source

September 13, 2006, 5:07 AM CT

Violence In The Home And Childhood Bullying

Children who were exposed to violence in the home engaged in higher levels of physical bullying than youngsters who were not witnesses to such behavior, as per a research studyby scientists from the University of Washington and Indiana University.

The study is one of the first in the United States to specifically examine the association between child exposure to intimate partner violence and involvement in bullying. It also is one of the first to break down bullying into physical aggression (hitting, pushing and other forms outward aggression) and relational aggression (teasing, being mean and ostracizing peers).

Overall, 34 percent of the children studied engaged in bullying and 73 percent reported being the victim of some form of bullying in the prior year. Almost all of the bullies, 97 percent, said they were also victims of bullying.

"Children learn from seeing what their primary caregivers do. They are very attuned and very observant about what goes on in a household," said Dr. Nerissa Bauer, lead author of the study and a former UW pediatrician who is now an assistant professor of pediatrics at Indian and Riley Children's Hospital.

"Parents are very powerful role models and children will mimic the behavior of parents, wanting to be like them. They may believe violence is OK and they can use it with peers. After all, they may think, 'If Daddy can do this, perhaps I can hit this kid to get my way.' When parents engage in violence, children may assume violence is the right way to do things," she said.........

Posted by: Sean      Permalink         Source

September 13, 2006, 4:26 AM CT

Behavioral And Mental Health Problems In Children

Limited access to services for children and adolescents with behavioral problems or mental illness often leads to inadequate care and treatment based on insufficient scientific evidence of safety and effectiveness, concludes a report by the American Psychological Association (APA) released recently.

According to the report, a product of the APA Working Group on Psychotropic Medications for Children and Adolescents, gaps in the scientific knowledge concerning which treatments work best for specific diagnoses and patients, a dearth of clinicians specifically trained to work with children, cuts in Medicaid funding, and poor reimbursement for mental health services leads to many children being treated with medicine despite limited efficacy and safety for their use particularly with children.

Research published earlier this year showed a five-fold increase in the use of antipsychotic drugs to treat behavioral and emotional problems in children and adolescents from 1993 to 2002.

"This entire state of affairs is in part related to our health care system's failure to provide sufficiently for children, particularly in the area of pediatric mental health care," states Ronald T. Brown, PhD, chair of the APA Working Group and Professor of Public Health and Dean at Temple University. "As a result, much of the care provided to children for mental health issues has been limited to medicine even though many psychosocial treatments have been found to be effective and some with better risk profiles. Psychosocial treatments, however, can be more labor intensive and more expensive".........

Posted by: Sean      Permalink         Source