September 29, 2009, 8:01 AM CT

Cultivating more corn for biofuels would hurt environment

More of the fertilizers and pesticides used to grow corn would find their way into nearby water sources if ethanol demands lead to planting more acres in corn, as per a Purdue University study.

The study of Indiana water sources observed that those near fields that practice continuous-corn rotations had higher levels of nitrogen, fungicides and phosphorous than corn-soybean rotations. Results of the study by Indrajeet Chaubey, an associate professor of agricultural and biological engineering, and Bernard Engel, a professor and head of agricultural and biological engineering, were reported in the early online version of The Journal of Environmental Engineering.

"When you move from corn-soybean rotations to continuous corn, the sediment losses will be much greater," Chaubey said. "Increased sediment losses allow more fungicide and phosphorous to get into the water because they move with sediment".

Nitrogen and fungicides are more heavily used in corn crops than soybeans, increasing the amounts found in the soil of continuous-corn fields. Sediment losses become more prevalent because tilling is often mandatory in continuous-corn fields, whereas corn-soybean rotations can more easily be no-till fields, Engel said.

"The common practice is there is a lot of tillage to put corn back on top of corn," Engel said. "Any time we see changes in the landscape, there is a potential to see changes in water quality"......... Posted by: Tyler      Read more         Source

September 28, 2009, 7:28 AM CT

How would Einstein use e-mail?

You're not as different from Albert Einstein and Charles Darwin after all, at least when it comes to patterns of correspondence.

A new Northwestern University study of human behavior has determined that those who wrote letters using pen and paper -- long before electronic mail existed -- did so in a pattern similar to the way people use e-mail today.

The study, published recently (Sept. 25) by the journal Science, demonstrates the similarity of these two seemingly different activities, with the underlying pattern of human activity linking letters and e-mails.

The scientists examined extensive letter correspondence records of 16 famous writers, performers, politicians and scientists, including Einstein, Darwin, Sigmund Freud, Karl Marx, and Ernest Hemingway, and observed that the 16 individuals sent letters randomly but in cycles.

The same mathematical model the Northwestern team used in a prior study to explain e-mail behavior now has been shown to apply to the letter writers. This refutes the rational model, which says that people are driven foremost by responding to others.

No matter what their profession, all the letter writers behaved the same way. They adhered to a circadian cycle; they tended to write many letters at one sitting, which is more efficient; and when they wrote had more to do with chance and circumstances than a rational approach of writing the most important letter first......... Posted by: Kevin      Read more         Source

September 28, 2009, 7:27 AM CT

New Type of Fast Computers Closer to Reality

Physicists at UC San Diego have successfully created speedy integrated circuits with particles called "excitons" that operate at commercially cold temperatures, bringing the possibility of a new type of extremely fast computer based on excitons closer to reality.

Their discovery, detailed this week in the advance online issue of the journal Nature Photonics, follows the team's demonstration last summer of an integrated circuit-an assembly of transistors that is the building block for all electronic devices-capable of working at 1.5 degrees Kelvin above absolute zero. That temperature, equivalent to minus 457 degrees Fahrenheit, is not only less than the average temperature of deep space, but achievable only in special research laboratories.

Now the researchers report that they have succeeded in building an integrated circuit that operates at 125 degrees Kelvin, a temperature that while still a chilly minus 234 degrees Fahrenheit, can be easily attained commercially with liquid nitrogen, a substance that costs about as much per liter as gasoline.

"Our goal is to create efficient devices based on excitons that are operational at room temperature and can replace electronic devices where a high interconnection speed is important," said Leonid Butov, a professor of physics at UCSD, who headed the research team. "We're still in an early stage of development. Our team has only recently demonstrated the proof of principle for a transistor based on excitons and research is in progress"......... Posted by: Kevin      Read more         Source

September 28, 2009, 6:40 AM CT

Pushing the cold frontier in an orderly fashion

Physicists are continually reaching new lows as they reduce the temperatures of samples in their laboratories. But even nano-kelvins are not low enough to overcome the entropy (a measure of the disorder in a system) that stands between them and the discovery of exotic states of ultra-cold matter. Now physicists at two Italian universities have developed a technique that siphons entropy out of a collection of atoms in much the same way that a kitchen refrigerator removes heat from the food stored inside. The new method is described in Physical Review Letters and highlighted in the September 28 issue of Physics (physics.aps.org).

The system that Jacopo Catani (University of Florence) and his colleagues assembled begins with a cloud of potassium and rubidium atoms held in a magnetic trap. They selected a laser with a wavelength of light that interacted with the potassium atoms, but had little effect on the rubidium atoms. They then compressed the potassium atom cloud by focusing the laser to a point in the trap. Compressing a gas commonly increases its temperature, but the surrounding rubidium kept things in check, allowing the scientists to hold the temperature roughly constant as entropy was shifted from the potassium to the rubidium atoms.

The novel technique should work with other combinations of atoms as well, offering scientists a new tool to aid them in their pursuit of physics at ultra-low temperatures and entropies......... Posted by: Kevin      Read more         Source

September 24, 2009, 7:04 AM CT

Genetic discovery could break wine industry bottleneck

One of the best known episodes in the 8000-year history of grapevine cultivation led to biological changes that have not been well understood until now. Through biomolecular detective work, German scientists have uncovered new details about the heredity of Vitis varieties in cultivation today. In the process, they have opened the way to more meaningful classification, accelerated breeding, and more accurate assessment of the results, potentially breaking a bottleneck in the progress of the wine industry. Their discovery removes a major obstacle to a development already under way that is, a shift toward grapevine breeding guided by highly specific genetic markers. It may even point the way toward production of European-tasting wines from North American cultivars, free of the "musty" or "foxy" flavors linked to New World grapevines.

In response to the "great European wine blight" of the mid-1800s, growers aimed at preserving the most desirable qualities of European grapes while breeding in the hardiness of North American varieties. These were naturally resistant to native pests that had found their way by steamship, most likely across the Atlantic to Europe. Beginning around 1860, the introduction of two North American pests an aphid and a fungus nearly destroyed the wine industry, especially in France. A century ago, a number of hybrids were in use, but the wine they produced was judged to be so inferior in flavor that winemakers were prohibited from blending them with higher-quality traditional wines......... Posted by: Kevin      Read more         Source

September 23, 2009, 7:09 AM CT

Diamonds may be the ultimate MRI probe

Diamonds, it has long been said, are a girl's best friend. But a research team including a physicist from the National Institute of Standards and Technology (NIST) has recently found* that the gems might turn out to be a patient's best friend as well.

The team's work has the long-term goal of developing quantum computers, but it has borne fruit that may have more immediate application in medical science. Their finding that a candidate "quantum bit" has great sensitivity to magnetic fields hints that MRI-like devices that can probe individual drug molecules and living cells appears to be possible.

The candidate system, formed from a nitrogen atom lodged within a diamond crystal, is promising not only because it can sense atomic-scale variations in magnetism, but also because it functions at room temperature. Most other such devices used either in quantum computation or for magnetic sensing must be cooled to nearly absolute zero to operate, making it difficult to place them near live tissue. However, using the nitrogen as a sensor or switch could sidestep that limitation.

Diamond, which is formed of pure carbon, occasionally has minute imperfections within its crystalline lattice. A common impurity is a "nitrogen vacancy", in which two carbon atoms are replaced by a single atom of nitrogen, leaving the other carbon atom's space vacant. Nitrogen vacancies are in part responsible for diamond's famed luster, for they are actually fluorescent: when green light strikes them, the nitrogen atom's two excitable unpaired electrons glow a brilliant red......... Posted by: Kevin      Read more         Source

September 20, 2009, 7:11 PM CT

Global Warming Causes Outbreak of Rare Algae

A rare opportunity has allowed a team of researchers to evaluate corals--and the essential, photosynthetic algae that live inside their cells--before, during, and after a period in 2005 when global warming caused sea-surface temperatures in the Caribbean to rise.

The team, led by Penn State biologist Todd LaJeunesse, observed that a rare species of algae that's tolerant of stressful environmental conditions proliferated in corals at a time when more sensitive algae that commonly dwell within the corals were being expelled.

The results would be reported in the online version of the journal Proceedings of the Royal Society B on September 9, 2009.

Certain species of algae have evolved over millions of years to live in symbiotic relationships with species of corals. These photosynthetic algae provide the corals with nutrients and energy, while the corals provide the algae with a place to live.

"There is a fine balance between giving and taking in these symbiotic relationships," said LaJeunesse.

Symbiodinium trenchi is normally a rare species of algae in the Caribbean, as per LaJeunesse. "Because the species is apparently tolerant of high or fluctuating temperatures, it was able to take advantage of a 2005 warming event and become more prolific"......... Posted by: Tyler      Read more         Source

September 20, 2009, 6:54 PM CT

World's river deltas sinking

A newly released study led by the University of Colorado at Boulder indicates most of the world's low-lying river deltas are sinking from human activity, making them increasingly vulnerable to flooding from rivers and ocean storms and putting tens of millions of people who are at risk.

While the 2007 Intergovernmental Panel on Climate Change report concluded a number of river deltas are at risk from sea level rise, the newly released study indicates other human factors are causing deltas to sink significantly. The scientists concluded the sinking of deltas from Asia and India to the Americas is exacerbated by the upstream trapping of sediments by reservoirs and dams, man-made channels and levees that whisk sediment into the oceans beyond coastal floodplains, and the accelerated compacting of floodplain sediment caused by the extraction of groundwater and natural gas.

The study concluded that 24 out of the world's 33 major deltas are sinking and that 85 percent experienced severe flooding in recent years, resulting in the temporary submergence of roughly 100,000 square miles of land. About 500 million people in the world live on river deltas.

Reported in the Sept. 20 issue of Nature Geoscience, the study was led by CU-Boulder Professor James Syvitski, who is directing a $4.2 million effort funded by the National Science Foundation to model large-scale global processes on Earth like erosion and flooding. Known as the Community Surface Dynamic Modeling System, or CSDMS, the effort involves hundreds of researchers from dozens of federal labs and universities around the nation......... Posted by: Tyler      Read more         Source

September 18, 2009, 6:34 PM CT

Slow-moving Marty headed for drier air

Marty was still holding onto tropical storm status on September 18, with maximum sustained winds near 40 mph and taking a slow march through the Eastern Pacific Ocean.

At 11 a.m. EDT he was located about 360 miles west-southwest of the southern tip of Baja California, near 18.9 north and 112.4 west. Marty is moving near 7 mph and has a minimum central pressure near 1004 millibars. Over the past two days, he only moved 40 miles!.

The GOES-11 satellite captured an image of Tropical Storm Marty off the western Mexican coast on September 18 at 12:45 p.m. EDT. GOES is operated by the National Oceanic and Atmospheric Administration. NASA's GOES Project, located at NASA's Goddard Space Flight Center, Greenbelt, Md. creates some of the satellite images from the GOES satellites.

The National Hurricane Center reported that there was a "burst of deep convection (rising air and thunderstorm development)" near Marty's center this morning, however, cloud top temperatures (as measured by NASA's Atmospheric Infrared Sounder (AIRS) instrument on the Aqua satellite) have begun to warm. Warming cloud top temperatures are indicative of thunderstorms that have less strength than those in stronger tropical cyclones.

Marty's fate over the weekend lies in cooler waters and drier air. Those are the two factors he's going to face as he continues moving, and they'll weaken him over the weekend. Marty will likely be a remnant low pressure area by the beginning of next week......... Posted by: Tyler      Read more         Source

September 18, 2009, 7:50 AM CT

Arctic sea ice reaches minimum extent for 2009

The Arctic sea ice cover appears to have reached its minimum extent for the year, the third-lowest recorded since satellites began measuring sea ice extent in 1979, as per the University of Colorado at Boulder's National Snow and Ice Data Center.

While this year's September minimum extent was greater than each of the past two record-setting and near-record-setting low years, it is still significantly below the long-term average and well outside the range of natural climate variability, said NSIDC Research Scientist Walt Meier. Most researchers believe the shrinking Arctic sea ice is tied to warming temperatures caused by an increase in human-produced greenhouse gases being pumped into Earth's atmosphere.

Atmospheric circulation patterns helped the Arctic sea ice spread out in August to prevent another record-setting minimum, said Meier. But most of the 2009 September Arctic sea ice is thin first- or second-year ice, rather than thicker, multi-year ice that used to dominate the region, said Meier.

The minimum 2009 sea-ice extent is still about 620,000 square miles below the average minimum extent measured between 1979 and 2000 -- an area nearly equal to the size of Alaska, said Meier. "We are still seeing a downward trend that may be heading toward ice-free Arctic summers," Meier said......... Posted by: Tyler      Read more         Source