January 29, 2008, 9:43 PM CT

Magnetism loses under pressure

Washington, D.C. Researchers have discovered that the magnetic strength of magnetitethe most abundant magnetic mineral on Earthdeclines drastically when put under pressure. Scientists from the Carnegie Institutions Geophysical Laboratory, together with colleagues at the Advanced Photon Source of Argonne National Laboratory, have observed that when magnetite is subjected to pressures between 120,000 and 160,000 times atmospheric pressure its magnetic strength declines by half. They discovered that the change is due to what is called electron spin pairing.

Magnetism comes from unpaired electrons in magnetic materials. The strength of a magnet is a result of the spin of unpaired electrons and how the spins of different electrons are aligned with one another. This research showed that the drop in magnetism was due to a decrease in the number of unpaired electrons.

Magnetite is found in small quantities in certain bacteria, in brains of some birds and insects, and even in humans, commented Yang Ding, the studys lead author with the Carnegie-led High-Pressure Synergetic Consortium. Early navigators used it to find the magnetic North Pole and birds use it for their navigation. And now it is used in nanotechnology. There is intense scientific interest in its properties. Understanding the behavior of magnetite is difficult because the strong interaction among its electrons complicates its electronic structure and magnetic properties......... Posted by: Sarah      Read more         Source

January 29, 2008, 9:31 PM CT

E.coli a future source of energy?

For most people, the name E. coli is synonymous with food poisoning and product recalls, but a professor in Texas A&M Universitys chemical engineering department envisions the bacteria as a future source of energy, helping to power our cars, homes and more.

By genetically modifying the bacteria, Thomas Wood, a professor in the Artie McFerrin Department of Chemical Engineering, has tweaked a strain of E. coli so that it produces substantial amounts of hydrogen. Specifically, Woods strain produces 140 times more hydrogen than is created in a naturally occurring process, as per an article in Microbial Biotechnology, detailing his research.

Though Wood acknowledges that there is still much work to be done before his research translates into any kind of commercial application, his initial success could prove to be a significant stepping stone on the path to the hydrogen-based economy that a number of believe is in this countrys future.

Renewable, clean and efficient, hydrogen is the key ingredient in fuel-cell technology, which has the potential to power everything from portable electronics to automobiles and even entire power plants. Today, most of the hydrogen produced globally is created by a process known as cracking water through which hydrogen is separated from the oxygen. But the process is expensive and requires vast amounts of energy one of the chief reasons why the technology has yet to catch on......... Posted by: Kevin      Read more         Source

January 29, 2008, 9:19 PM CT

Agriculture is changing the chemistry of the Mississippi

Midwestern farming has introduced the equivalent of five Connecticut Rivers into the Mississippi River over the past 50 years and is adding more carbon dioxide annually into its waters, as per a research studypublished in Nature by scientists at Yale and Louisiana State universities.

Its like the discovery of a new large river being piped out of the corn belt, said Pete Raymond, lead author of the study and associate professor of ecosystem ecology at the Yale School of Forestry & Environmental Studies. Agricultural practices have significantly changed the hydrology and chemistry of the Mississippi River.

The scientists tracked changes in the levels of water and bicarbonate, which forms when carbon dioxide in soil water dissolves rock minerals. Bicarbonate plays an important, long-term role in absorbing atmospheric carbon dioxide, a greenhouse gas. Oceans then absorb the excess carbon dioxide and become more acidic in the process. Ocean acidification makes it more difficult for organisms to form hard shells in coral reefs, said R. Eugene Turner, a co-author of the study and a professor at the Coastal Ecology Institute at Louisiana State University.

The scientists concluded that farming practices, such as liming, changes in tile drainage and crop type and rotation, are responsible for the majority of the increase in water and carbon dioxide in the Mississippi River, which is North Americas largest river......... Posted by: Tyler      Read more         Source

January 28, 2008, 10:42 PM CT

Baffin Island ice caps shrink by 50 percent since 1950s

A new University of Colorado at Boulder study has shown that ice caps on the northern plateau of Baffin Island in the Canadian Arctic have shrunk by more than 50 percent in the last half century as a result of warming, and are expected to disappear by the middle of the century.

Radiocarbon dating of dead plant material emerging from beneath the receding ice margins show the Baffin Island ice caps are now smaller in area than at any time in at least the last 1,600 years, said geological sciences Professor Gifford Miller of CU-Boulder's Institute of Arctic and Alpine Research. "Even with no additional warming, our study indicates these ice caps will be gone in 50 years or less," he said.

The study also showed two distinct bursts of Baffin Island ice-cap growth commencing about 1280 A.D. and 1450 A.D., each coinciding with ice-core records of increases in stratospheric aerosols tied to major tropical volcanic eruptions, Miller said. The unexpected findings "provide tantalizing evidence that the eruptions were the trigger for the Little Ice Age," a period of Northern Hemisphere cooling that lasted from roughly 1250 to 1850, he said.

A paper on the subject was published online in Geophysical Research Letters and featured in the Jan. 28 edition of the American Geophysical Union journal highlights. Authors on the study included Miller, graduate students Rebecca Anderson and Stephen DeVogel of INSTAAR, Jason Briner of the State University of New York at Buffalo and Nathaniel Lifton of the University of Arizona......... Posted by: Tyler      Read more         Source

January 28, 2008, 10:30 PM CT

Lessons from evolution applied to national security

Could lessons learned from Mother Nature help airport security screening checkpoints better protect us from terror threats? .

The authors of a new book, Natural Security: A Darwinian Approach to a Dangerous World, believe they can -- if governments are willing to think outside the box and pay heed to some of natures most successful evolutionary strategies for species adaptation and survival.

Biological organisms have figured out millions of ways, over three and a half billion years of evolution, to keep themselves safe from a vast array of threats, said Raphael Sagarin, a Duke University ecologist who co-edited the book with Terence Taylor, an international security expert.

Arms races among invertebrates, intelligence gathering by the immune system and alarm calls by marmots are just a few of natures successful security strategies that have been tested and modified over time in response to changing threats and situations, Sagarin said. In our book, we look at these strategies and ask how we could apply them to our own safety.

The book, published next month by the University of California Press, is the result of more than two years of investigation and debate by a multidisciplinary working group of researchers and security experts led by Sagarin and Taylor......... Posted by: Jaison      Read more         Source

January 28, 2008, 10:17 PM CT

Less fish out, means more nitrogen in

A Canada-U.S. research team has observed that commercial fisheries play an unexpected role in the decline of water quality in coastal waters. In the latest issue of Nature Geoscience, Roxane Maranger and Nina Caraco explain that the collapse of the fisheries from decades of over fishing has played a significant role in disturbing the balance between nitrogen entering and leaving costal water systems.

The study, the first to examine the worlds 58 coatal regions, shows how failing to maintain ecosystems in a sustainable manner has wide-ranging consequences. Using data provided by the United Nations, Maranger and Caraco observed that commercial fishing has played an important, yet declining, role in removing man-made nitrogen from coastal waters.

Fish accumulate nitrogen as biomass, and when humans move fish from the ocean to the table through commercial fisheries, they are returning part of this terrestrial nitrogen generated by humans back to the land, said Maranger, a biology professor at the Universit de Montral (Canada).

Caraco, an aquatic biogeochemist at the Cary Institue of Ecosystem Studies (Millbrook, New York, U.S.) notes: While nitrogen is essential to plant and animal life in oceans, human export of nitrogen from land to ocean has resulted in exploding nitrogen levels in coastal waters over the past century. Nitrogen-rich fertilizer thats applied to farmland eventually makes its way into coastal waters via a network of streams and rivers. Fertilizer run-off is a significant source of nitrogen pollution to a number of coastal regions around the world......... Posted by: Tyler      Read more         Source

January 24, 2008, 11:12 PM CT

Sheds light on ocean current dynamics

Ocean surface currents have long been the focus of research due to the role they play in weather, climate and transportation of pollutants, yet essential aspects of these currents remain unknown.

By employing a new technique - based on the same principle as police speed-measuring radar guns - to satellite radar data, researchers can now obtain information necessary to understand better the strength and variability of surface current regimes and their relevance for climate change.

Researchers at the SeaSAR 2008 workshop held this week in ESRIN, ESA's European Centre for Earth Observation in Frascati, Italy, demonstrated how this new method on data from the Advanced Synthetic Aperture Radar (ASAR) instrument aboard ESA's Envisat, enabled measurements of the speed of the moving ocean surface.

Synthetic Aperture Radar (SAR) instruments, such as ASAR, record microwave radar backscatter in order to identify roughness patterns, which are associated with varying surface winds, waves and currents of the ocean surface. However, interpreting radar images to identify and quantify surface currents had proven very difficult.

By using the new information embedded in the radar signal - the Doppler shift of the electromagnetic waves reflected from the water surface - Dr Bertrand Chapron of the French Research Institute for Exploitation of the Sea (IFREMER), Dr Johnny Johannessen of Norway's Nansen Environmental and Remote Sensing Centre (NERSC) and Dr Fabrice Collard of France's BOOST Technologies were able to determine how surface winds and currents contribute to the Doppler shift......... Posted by: Tyler      Read more         Source

January 24, 2008, 11:08 PM CT

Climate change poses a huge threat to human health

Climate change will have a huge impact on human health and bold environmental policy decisions are needed now to protect the worlds population, as per the author of an article reported in the BMJ today.

The threat to human health is of a more fundamental kind than is the threat to the worlds economic system, says Professor McMichael, a Professor of public health from the Australian National University. Climate change is beginning to damage our natural life-support system, he says.

The risks to health are a number of, and include the impact of heat waves, floods and wildfires, changes in infectious disease patterns, the effect of worsening food yields and loss of livelihoods.

The World Health Organisation estimates that a quarter of the worlds disease burden is due to the contamination of air, water, soil and food especially from respiratory infections and diarrhoeal disease.

Climate change, says Professor McMichael, will make these and other diseases worse. While it is unlikely to cause entirely new diseases it will alter the incidence, range and seasonality of a number of existing health disorders. So, for example, by 2080 between 20 and 70 million more people could be living in malarial regions due to climate change.

The adverse health impacts will be much greater in low-income countries and vulnerable sub-populations than in richer nations......... Posted by: Tyler      Read more         Source

January 24, 2008, 11:04 PM CT

New Discoveries At The Ash Altar Of Zeus

The Greek traveler, Pausanias, living in the second century, CE, would probably recognize the spectacular site of the Sanctuary of Zeus at Mt. Lykaion, and especially the altar of Zeus. At 4,500 feet above sea level, atop the altar provides a breathtaking, panoramic vista of Arcadia.

"On the highest point of the mountain is a mound of earth, forming an altar of Zeus Lykaios, and from it most of the Peloponnesos can be seen," wrote Pausanias, in his famous, well-respected multi-volume Description of Greece. "Before the altar on the east stand two pillars, on which there were of old gilded eagles. On this altar they sacrifice in secret to Lykaion Zeus. I was reluctant to pry into the details of the sacrifice; let them be as they are and were from the beginning".

What would surprise Pausanias-as it is surprising archaeologists-is how early that "beginning" actually may be. New pottery evidence from excavations by the Greek-American, interdisciplinary team of the Mt. Lykaion Excavation and Survey Project indicates that the ash altar-a cone of earth located atop the southern peak of Mt Lykaion where dedications were made in antiquity- was in use as early as 5,000 years ago-at least 1,000 years before the early Greeks began to worship the god Zeus.

In addition, a rock crystal seal, bearing an image of a bull, of probable Late Minoan times (1500-1400 BCE) and also found on the altar, suggests an intriguing early correlation between the Minoan isle of Crete and Arcadia, and bears witness to another chapter in what now appears to be an particularly long history of activity atop the mountain......... Posted by: William      Read more         Source

January 24, 2008, 11:00 PM CT

When accounting for the global nitrogen budget, don't forget fish

Like bank accounts, the nutrient cycles that influence the natural world are regulated by inputs and outputs. If a routine withdrawal is overlooked, balance sheets become inaccurate. Over time, overlooked deductions can undermine our ability to understand and manage ecological systems.

Recent research by the Universite de Montreal (Canada) and the Cary Institute of Ecosystem Studies (Millbrook, New York) has revealed an important, but seldom accounted for, withdrawal in the global nitrogen cycle: commercial fisheries. Results, published as the cover story in the recent issue of Nature Geoscience, highlight the role that fisheries play in removing nitrogen from coastal oceans.

Nitrogen is essential to plant and animal life; however, it is possible to have too much of a good thing. During the past century, a range of human activities have increased nitrogen inputs to coastal waters. Fertilizer run-off is the best documented and most significant source of terrestrial nitrogen pollution. Nitrogen-rich fertilizer applied to farmland eventually makes its way into coastal waters via a network of streams and rivers.

Research spearheaded by Roxane Maranger (Universite de Montreal) and Nina Caraco (Cary Institute) demonstrates that commercial fisheries play an important but declining role in removing terrestrial nitrogen from coastal waters. Accounting for this withdrawal is crucial; terrestrial-derived nitrogen can stimulate coastal phytoplankton growth, leading to eutrophication. Typically typically eutrophic waters are characterized by reduced dissolved oxygen, decreased biodiversity, and species composition shifts......... Posted by: Tyler      Read more         Source