June 25, 2009, 7:12 PM CT

Demand for food, energy demand to outpace production

With the caloric needs of the planet expected to soar by 50 percent in the next 40 years, planning and investment in global agriculture will become critically important, according a new report released recently (June 25).

The report, produced by Deutsche Bank, one of the world's leading global investment banks, in collaboration with the University of Wisconsin-Madison's Nelson Institute for Environmental Studies, provides a framework for investing in sustainable agriculture against a backdrop of massive population growth and escalating demands for food, fiber and fuel.

"We are at a crossroads in terms of our investments in agriculture and what we will need to do to feed the world population by 2050," says David Zaks, a co-author of the report and a researcher at the Nelson Institute's Center for Sustainability and the Global Environment.

By 2050, world population is expected to exceed 9 billion people, up from 6.5 billion today. Already, as per the report, a gap is emerging between agricultural production and demand, and the disconnect is expected to be amplified by climate change, increasing demand for biofuels, and a growing scarcity of water.

"There will come a point in time when we will have difficulties feeding world population," says Zaks, a graduate student whose research focuses on the patterns, trends and processes of global agriculture......... Posted by: Tyler      Read more         Source

June 21, 2009, 9:25 PM CT

A glimpse of things to come

Herschel opened its 'eyes' on 14 June and the Photoconductor Array Camera and Spectrometer obtained images of M51, 'the whirlpool galaxy' for a first test observation. Researchers obtained images in three colours which clearly demonstrate the superiority of Herschel, the largest infrared space telescope ever flown.

This image shows the famous 'whirlpool galaxy', first observed by Charles Messier in 1773, who provided the designation Messier 51 (M51). This spiral galaxy lies relatively nearby, about 35 million light-years away, in the constellation Canes Venatici. M51 was the first galaxy discovered to harbour a spiral structure.

The image is a composite of three observations taken at 70, 100 and 160 microns, taken by Herschel's Photoconductor Array Camera and Spectrometer (PACS) on 14 and 15 June, immediately after the satellite's cryocover was opened on 14 June.

Herschel, launched only a month ago, is still being commissioned and the first images from its instruments were planned to arrive only in a few weeks. But engineers and researchers were challenged to try to plan and execute daring test observations as part of a 'sneak preview' immediately after the cryocover was opened. The objective was to produce a very early image that gives a glimpse of things to come......... Posted by: Brooke      Read more         Source

June 21, 2009, 8:46 PM CT

Dino-not-so-soaring

The largest animals ever to have walked the face of the earth may not have been as big as previously thought, reveals a paper published recently in the Zoological Society of London's Journal of Zoology

Researchers have discovered that the original statistical model used to calculate dinosaur mass is flawed, suggesting dinosaurs have been oversized.

Widely cited estimates for the mass of Apatosaurus louisae, one of the largest of the dinosaurs, appears to be double that of its actual mass (38 tonnes vs. 18 tonnes).

"Paleontologists have for 25 years used a published statistical model to estimate body weight of giant dinosaurs and other extraordinarily large animals in extinct lineages. By re-examining data in the original reference sample, we show that the statistical model is seriously flawed and that the giant dinosaurs probably were only about half as heavy as is generally believed" says Gary Packard from Colorado State University.

The new predictions have implications for numerous theories about the biology of dinosaurs, ranging from their energy metabolism to their food requirements and to their modes of locomotion......... Posted by: William      Read more         Source

June 21, 2009, 8:40 PM CT

In a Geologic Instant

Modern glaciers, such as those making up the Greenland and Antarctic ice sheets, are capable of undergoing periods of rapid shrinkage or retreat, as per new findings by paleoclimatologists at the University at Buffalo.

The paper, published on June 21 in Nature Geoscience, describes fieldwork demonstrating that a prehistoric glacier in the Canadian Arctic rapidly retreated in just a few hundred years.

The proof of such rapid retreat of ice sheets provides one of the few explicit confirmations that this phenomenon occurs.

Should the same conditions recur today, which the UB researchers say is very possible, they would result in sharply rising global sea levels, which would threaten coastal populations.

"A lot of glaciers in Antarctica and Greenland are characteristic of the one we studied in the Canadian Arctic," said Jason Briner, Ph.D., assistant professor of geology in the UB College of Arts and Sciences and main author on the paper. "Based on our findings, they, too, could retreat in a geologic instant."

The new findings will allow researchers to more accurately predict how global warming will affect ice sheets and the potential for rising sea levels in the future, by developing more robust climate and ice sheet models.

Briner said the findings are particularly relevant to the Jakobshavn Isbrae, Greenland's largest and fastest moving tidewater glacier, which is retreating under conditions similar to those he studied in the Canadian Arctic......... Posted by: Tyler      Read more         Source

June 16, 2009, 9:44 PM CT

Climate change is already having an impact

Extreme weather, drought, heavy rainfall and increasing temperatures are a fact of life in a number of parts of the U.S. as a result of human-induced climate change, scientists report today in a new evaluation. These and other changes will continue and likely increase in intensity into the future, the researchers found.

Scientists representing 13 U.S. government science agencies, major universities and research institutes produced the study, "Global Climate Change Impacts in the United States." Commissioned in 2007, it is the most comprehensive report to date on national climate change, offering the latest information on rising temperatures, heavy downpours, extreme weather, sea level changes and other results of climate change in the U.S.

The 190-page report is a product of the interagency U.S. Global Change Research Program, led by the National Oceanic and Atmospheric Administration. It is written in accessible language, intended to better inform members of the public and policymakers about the social, environmental and economic costs of climate change. It focuses on effects by region and details how the nation's transportation, agriculture, health, water and energy sectors will be affected in the future.

In a press conference today, University of Illinois Harry E. Preble Professor of Atmospheric Sciences Don Wuebbles, a contributor to the evaluation, outlined the current and predicted effects of climate change in the Midwest U.S......... Posted by: Tyler      Read more         Source

June 16, 2009, 9:42 PM CT

Extreme makeover chemistry style

In revisiting a chemical reaction that's been in the literature for several decades and adding a new wrinkle of their own, scientists with Berkeley Lab and the University of California (UC) Berkeley have discovered a mild and relatively inexpensive procedure for removing oxygen from biomass. This procedure, if it can be effectively industrialized, could allow a number of of today's petrochemical products, including plastics, to instead be made from biomass.

"We've found and optimized a selective, one-pot deoxygenation technique based on a formic acid therapy," said Robert Bergman, a co-principal investigator on this project who holds a joint appointment with Berkeley Lab's Chemical Sciences Division and the UC Berkeley Chemistry Department.

The formic acid, Bergman said, converts glycerol, a major and unwanted by-product in the manufacturing of biodiesel, into allyl alcohol, which is used as a starting material in the manufacturing of polymers, drugs, organic compounds, herbicides, pesticides and other chemical products. Allyl alcohol today is produced from the oxidation of petroleum.

Said Jonathan Ellman, a UC Berkeley chemistry professor and the other principal investigator in this research, "Right now, about five percent of the world's supply of petroleum is used to make feedstocks that are synthesized into commodity chemicals. If these feedstocks can instead be made from biomass they become renewable and their production will no longer be a detriment to the environment"......... Posted by: Sarah      Read more         Source

June 16, 2009, 5:17 AM CT

Magnetic Superatoms

A team of Virginia Commonwealth University researchers has discovered a 'magnetic superatom' - a stable cluster of atoms that can mimic different elements of the periodic table - that one day appears to be used to create molecular electronic devices for the next generation of faster computers with larger memory storage.

The newly discovered cluster, consisting of one vanadium and eight cesium atoms, acts like a tiny magnet that can mimic a single manganese atom in magnetic strength while preferentially allowing electrons of specific spin orientation to flow through the surrounding shell of cesium atoms. The findings appear online in the journal Nature Chemistry.

Through an elaborate series of theoretical studies, Shiv N. Khanna, Ph.D., professor in the VCU Department of Physics, together with VCU postdoctoral associates J. Ulises Reveles, A.C. Reber, and graduate student P. Clayborne, and collaborators at the Naval Research Laboratory in D.C., and the Harish-Chandra Research Institute in Allahabad, India, examined the electronic and magnetic properties of clusters having one vanadium atom surrounded by multiple cesium atoms.

They observed that when the cluster had eight cesium atoms it acquired extra stability due to a filled electronic state. An atom is in a stable configuration when its outermost shell is full. Consequently, when an atom combines with other atoms, it tends to lose or gain valence electrons to acquire a stable configuration......... Posted by: Kevin      Read more         Source

June 16, 2009, 5:08 AM CT

Sediment Yields Climate Record For Past Half-million Years

Scientists here have used sediment from the deep ocean bottom to reconstruct a record of ancient climate that dates back more than the last half-million years.

The record, trapped within the top 20 meters (65.6 feet) of a 400-meter (1,312-foot) sediment core drilled in 2005 in the North Atlantic Ocean by the Integrated Ocean Drilling Program, gives new information about the four glacial cycles that occurred during that period.

The new research was presented today at the Chapman Conference on Abrupt Climate Change at Ohio State University's Byrd Polar Research Center. The meeting is jointly sponsored by the American Geophysical Union and the National Science Foundation.

Harunur Rashid, a post-doctoral fellow at the Byrd Center, explained that experts have been trying to capture a longer climate record for this part of the ocean for nearly a half-century. "We've now generated a climate record from this core that has a very high temporal resolution, one that is decipherable at increments of 100 to 300 years," he said.

While climate records from ice cores can show resolutions with individual annual layers, ocean sediment cores are greatly compressed with resolutions sometimes no finer than millennia.

"What we have is unprecedented among marine records"......... Posted by: William      Read more         Source

June 10, 2009, 9:43 PM CT

A new measure of global warming from carbon emissions

Damon Matthews, a professor in Concordia University's Department of Geography, Planning and the Environment has found a direct relationship between carbon dioxide emissions and global warming. Matthews, together with colleagues from Victoria and the U.K., used a combination of global climate models and historical climate data to show that there is a simple linear relationship between total cumulative emissions and global temperature change. These findings would be reported in the next edition of Nature, to be released on June 11, 2009.

Until now, it has been difficult to estimate how much climate will warm in response to a given carbon dioxide emissions scenario because of the complex interactions between human emissions, carbon sinks, atmospheric concentrations and temperature change. Matthews and his colleagues show that despite these uncertainties, each emission of carbon dioxide results in the same global temperature increase, regardless of when or over what period of time the emission occurs.

These findings mean that we can now say: if you emit that tonne of carbon dioxide, it will lead to 0.0000000000015 degrees of global temperature change. If we want to restrict global warming to no more than 2 degrees, we must restrict total carbon emissions from now until forever to little more than half a trillion tonnes of carbon, or about as much again as we have emitted since the beginning of the industrial revolution......... Posted by: Tyler      Read more         Source

June 10, 2009, 8:42 PM CT

Maybe it's raining less than we thought

It's conventional wisdom in atmospheric science circles: large raindrops fall faster than smaller drops, because they're bigger and heavier. And no raindrop can fall faster than its "terminal speed"its speed when the downward force of gravity is exactly the same as the upward air resistance.

Now two physicists from Michigan Technological University and his colleagues at the Universidad Nacional Autnoma de Mxico (National University of Mexico) have discovered that it ain't necessarily so.

Some smaller raindrops can fall faster than bigger ones. In fact, they can fall faster than their terminal speed. In other words, they can fall faster than drops that size and weight are supposed to be able to fall.

And that could mean that the weatherman has been overestimating how much it rains.

The findings of Michigan Tech physics professors Alexander Kostinski and Raymond Shawco-authors with Guillermo Montero-Martinez and Fernando Garcia-Garcia on a paper scheduled for publication online June 13, 2009, in the American Geophysical Union's journal Geophysical Research Letterscould improve the accuracy of weather measurement and prediction.

The scientists gathered data during natural rainfalls at the Mexico City campus of the National University of Mexico. They studied approximately 64,000 raindrops over three years, using optical array spectrometer probes and a particle analysis and collecting system. They also modified an algorithm or computational formula to analyze the raindrop sizes......... Posted by: Tyler      Read more         Source

June 5, 2009, 5:00 AM CT

Graphene May Have Advantages Over Copper

The unique properties of thin layers of graphite-known as graphene-make the material attractive for a wide range of potential electronic devices. Scientists have now experimentally demonstrated the potential for another graphene application: replacing copper for interconnects in future generations of integrated circuits.

In a paper reported in the June 2009 issue of the IEEE journal Electron Device Letters, scientists at the Georgia Institute of Technology report detailed analysis of resistivity in graphene nanoribbon interconnects as narrow as 18 nanometers.

The results suggest that graphene could out-perform copper for use as on-chip interconnects-tiny wires that are used to connect transistors and other devices on integrated circuits. Use of graphene for these interconnects could help extend the long run of performance improvements for silicon-based integrated circuit technology.

"As you make copper interconnects narrower and narrower, the resistivity increases as the true nanoscale properties of the material become apparent," said Raghunath Murali, a research engineer in Georgia Tech's Microelectronics Research Center and the School of Electrical and Computer Engineering. "Our experimental demonstration of graphene nanowire interconnects on the scale of 20 nanometers shows that their performance is comparable to even the most optimistic projections for copper interconnects at that scale. Under real-world conditions, our graphene interconnects probably already out-perform copper at this size scale."........ Posted by: Kevin      Read more         Source

June 5, 2009, 4:56 AM CT

Nanoscale zipper cavity

Physicists at the California Institute of Technology (Caltech) have developed a nanoscale device that can be used for force detection, optical communication, and more. The device exploits the mechanical properties of light to create an optomechanical cavity in which interactions between light and motion are greatly strengthened and enhanced. These interactions, notes Oskar Painter, associate professor of applied physics at Caltech, and the principal investigator on the research, are the largest demonstrated to date.

The device and the work that led to it are described in a recent issue of the journal Nature

The fact that photons of light, despite having no mass, nonetheless carry momentum and can interact with mechanical objects is an idea that dates back to Kepler and Newton. The mechanical properties of light are also known to limit the precision with which one can measure an object's position, since simply by using light to do the measurement, you apply a force and disturb the object.

It was important to consider these so-called back-action effects in the design of devices to measure weak, classical forces. Such considerations were part of the development of gravity-wave detectors like the Laser Interferometer Gravitational-Wave Observatory (LIGO). These sorts of interferometer-based detectors have also been used at much smaller scales, in scanning probe instruments used to detect or image atomic surfaces or even single electron spins......... Posted by: Kevin      Read more         Source

June 3, 2009, 5:10 AM CT

Control heat in large data centers

Approximately a third of the electricity consumed by large data centers doesn't power the computer servers that conduct online transactions, serve Web pages or store information. Instead, that electricity must be used for cooling the servers, a demand that continues to increase as computer processing power grows.

And the trend toward cloud computing will expand the need for both servers and cooling.

At the Georgia Institute of Technology, scientists are using a 1,100-square-foot simulated data center to optimize cooling strategies and develop new heat transfer models that can be used by the designers of future facilities and equipment. The goal is to reduce the portion of electricity used to cool data center equipment by as much as 15 percent.

"Computers convert electricity to heat as they operate," said Yogendra Joshi, a professor in Georgia Tech's Woodruff School of Mechanical Engineering. "As they switch on and off, transistors produce heat, and all of that heat must be ultimately transferred to the environment. If you are looking at a few computers, the heat produced is not that much. But data centers generate heat at the rate of tens of megawatts that must be removed".

Summaries of the research have been reported in the Journal of Electronic Packaging and International Journal of Heat and Mass Transfer and presented at the Second International Conference on Thermal Issues in Emerging Technologies, Theory and Applications. The research has been sponsored by the U.S. Office of Naval Research, and by the Consortium for Energy Efficient Thermal Management......... Posted by: Kevin      Read more         Source

June 3, 2009, 5:01 AM CT

Memory with a twist

Electronic memory chips may soon gain the ability to bend and twist as a result of work by engineers at the National Institute of Standards and Technology (NIST). As published in the July 2009 issue of IEEE Electron Device Letters,* the engineers have found a way to build a flexible memory component out of inexpensive, readily available materials.

Though still not ready for the marketplace, the new device is promising not only because of its potential applications in medicine and other fields, but because it also appears to possess the characteristics of a memristor, a fundamentally new component for electronic circuits that industry researchers developed in 2008.** NIST has filed for a patent on the flexible memory device (application #12/341.059).

Electronic components that can flex without breaking are coveted by portable device manufacturers for a number of reasonsand not just because people have a tendency to drop their mp3 players. Small medical sensors that can be worn on the skin to monitor vital signs such as heart rate or blood sugar could benefit patients with conditions that require constant maintenance, for example. Though some flexible components exist, creating flexible memory has been a technical barrier, as per NIST researchers.

Hunting for a solution, the scientists took polymer sheetsthe sort that transparencies for overhead projectors are made fromand experimented with depositing a thin film of titanium dioxide, an ingredient in sunscreen, on their surfaces. Instead of using expensive equipment to deposit the titanium dioxide as is traditionally done, the material was deposited by a sol gel process, which consists of spinning the material in liquid form and letting it set, like making gelatin. By adding electrical contacts, the team created a flexible memory switch that operates on less than 10 volts, maintains its memory when power is lost, and still functions after being flexed more than 4,000 times......... Posted by: Kevin      Read more         Source

June 1, 2009, 6:56 PM CT

Nanosecond pressure jump

A new method to induce protein folding by taking the pressure off of proteins is up to 100 times faster than prior methods, and could help guide more accurate computer simulations for how complex proteins fold, as per research by a team of University of Illinois researchers accepted for publication in the journal Nature Methods and posted on the journal's Web site May 31.

Martin Gruebele, the James R. Eiszner Professor of Chemistry at the U. of I. and corresponding author of the paper, says that prodding proteins to fold by suddenly removing high pressure (a technique also known as "pressure jumping") through electrical bursting makes for a "kindler, gentler way" of inducing proteins to fold.

"When you're increasing the pressure on something, you're squeezing the atoms and making them come closer to one another," Gruebele said, "but you're not necessarily causing the very complicated changes to the microscopic motion that occur when you change the temperature. Pressure is a simpler variable than temperature".

In order to carry out their biomolecular functions, proteins fold from a chaotic, random coil that looks like spaghetti strands floating in boiling water to their native state as an orderly, well-defined but compact structure.

From the point-of-view of the protein, Gruebele said, pressurizing it to about 2,500 atmospheres is much less disruptive than, say, cranking up the temperature by 30 degrees......... Posted by: Kevin      Read more         Source

June 1, 2009, 4:58 AM CT

Population responses to climate change

Biologists have for several years modeled how different species are likely to respond to climate change. Most such studies ignore differences between populations within a species and the interactions between species, in the interest of simplicity. An article in the recent issue of BioScience, by Eric Post of Pennsylvania State University and five colleagues, shows how these limitations can be avoided. Their approach, which relies on multi-stage analyses of how populations fluctuate over time, could allow biologists to model responses to climate change with improved accuracy. In particular, the approach could help identify regions where local populations are vulnerable to climate change, and it could elucidate species interactions that may not be obvious.

The article concentrates on recent analyses by Post and others of yellow-billed cuckoos, caribou/wild reindeer, elk and red deer, and wolves and moose. Continent-wide and hemisphere-wide responses depended both on local weather and on broader climate patterns, and all species showed marked variation among populations. The pattern of responses, Post and his colleagues report, "suggests a strong role for species interactions in buffering responses to climate." For example, local populations near the northern edge of a species' range often seem to be more directly affected by climate than do populations near the southern edge, where biological interactions typically complicate responses to climate change......... Posted by: Tyler      Read more         Source

June 1, 2009, 4:57 AM CT

Who will pick up the bill?

Ocean acidification, a direct result of increased CO2 emission, is set to change the Earth's marine ecosystems forever and may have a direct impact on our economy, resulting in substantial revenue declines and job losses.

Intensive fossil-fuel burning and deforestation over the last two centuries have increased atmospheric CO2 levels by almost 40%, which has in turn fundamentally altered ocean chemistry by acidifying surface waters. Fish levels and other sea organisms such as planktons, crabs, lobsters, shrimp and corals are expected to suffer, which could leave fishing communities at the brink of economic disaster.

Published recently, Monday, 1 June, in IOP Publishing's Environmental Research Letters, the paper 'Anticipating ocean acidification's economic consequences on commercial fisheries' suggests a series of measures to manage the impact that declining fishing harvests and revenue loss will have on a wide range of businesses from commercial fishing to wholesale, retail and restaurants.

Ocean acidification and declining carbonate ion concentration in sea water could directly damage corals and mollusks which all depend on sufficient carbonate levels to form shells successfully. Subsequent losses of prey such as plankton and shellfish would also alter food webs and intensify competition among predators for nourishment......... Posted by: Tyler      Read more         Source

May 28, 2009, 5:19 AM CT

Sea-level rise may pose greatest threat

The melting of the Greenland Ice Sheet this century may drive more water than previously thought toward the already threatened coastlines of New York, Boston, Halifax and other cities in the northeastern United States and Canada, as per new research.

Results of the study are being published this week in Geophysical Research Letters They suggest that moderate to high rates of ice melt from Greenland may shift ocean circulation by about 2100, causing sea levels off the northeast coast of North America to rise by about 30 to 51 centimeters (12 to 20 inches) more than other coastal areas.

The research builds on recent reports that have observed that sea level rise could adversely affect North America, and its findings suggest that the situation is even more urgent than previously believed.

"If the Greenland melt continues to accelerate, we could see significant impacts this century on the northeast U.S. coast from the resulting sea level rise," says scientist Aixue Hu, the paper's main author. Hu is at the National Center for Atmospheric Research (NCAR) in Boulder, Colo. "Major northeastern cities are directly in the path of the greatest rise".

A study in Nature Geoscience in March warned that warmer water temperatures could shift ocean currents in a way that would raise sea levels off the Northeast by about eight inches more than the average global sea level rise that is expected with global warming......... Posted by: Tyler      Read more         Source

May 24, 2009, 8:57 PM CT

Multiferroics

Multiferroics are materials in which unique combinations of electric and magnetic properties can simultaneously coexist. They are potential cornerstones in future magnetic data storage and spintronic devices provided a simple and fast way can be found to turn their electric and magnetic properties on and off. In a promising new development, scientists with the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) working with a prototypical multiferroic have successfully demonstrated just such a switch -- electric fields.

"Using electric fields, we have been able to create, erase and invert pn junctions in a calcium-doped bismuth ferrite film," said Ramamoorthy Ramesh of Berkeley Lab's Materials Sciences Division (MSD), who led this research.

"Through the combination of electronic conduction with the electric and magnetic properties already present in the multiferroic bismuth ferrite, our demonstration opens the door to merging magnetoelectrics and magnetoelectronics at room temperature".

Ramesh, who is also a professor in the Department of Materials Science and Engineering and the Department of Physics at UC Berkeley, has published a paper on this research that is now available in the on-line edition of the journal Nature Materials The paper is titled: "Electric modulation of conduction in multiferroic......... Posted by: Kevin      Read more         Source

May 20, 2009, 5:12 AM CT

Global warming could be double previous estimates

The most comprehensive modeling yet carried out on the likelihood of how much hotter the Earth's climate will get in this century shows that without rapid and massive action, the problem will be about twice as severe as previously estimated six years ago - and could be even worse than that.

The study uses the MIT Integrated Global Systems Model, a detailed computer simulation of global economic activity and climate processes that has been developed and refined by the Joint Program on the Science and Policy of Global Change since the early part of 1990s. The new research involved 400 runs of the model with each run using slight variations in input parameters, selected so that each run has about an equal probability of being correct based on present observations and knowledge. Other research groups have estimated the probabilities of various outcomes, based on variations in the physical response of the climate system itself. But the MIT model is the only one that interactively includes detailed therapy of possible changes in human activities as well - such as the degree of economic growth, with its associated energy use, in different countries.

Co-author of study Ronald Prinn, the co-director of the Joint Program and director of MIT's Center for Global Change Science, says that, regarding global warming, it is important "to base our opinions and policies on the peer-evaluated science," he says. And in the peer-evaluated literature, the MIT model, unlike any other, looks in great detail at the effects of economic activity coupled with the effects of atmospheric, oceanic and biological systems. "In that sense, our work is unique," he says......... Posted by: Tyler      Read more         Source

May 19, 2009, 5:29 AM CT

Concrete's Carbon Footprint

A number of researchers currently think at least 5 percent of humanity's carbon footprint comes from the concrete industry, both from energy use and the carbon dioxide (CO2) byproduct from the production of cement, one of concrete's principal components.

Yet several studies have shown that small quantities of CO2 later reabsorb into concrete, even decades after it is emplaced, when elements of the material combine with CO2 to form calcite.

A study appearing in the June 2009 Journal of Environmental Engineering suggests that the re-absorption may extend to products beyond calcite, increasing the total CO2 removed from the atmosphere and lowering concrete's overall carbon footprint.

While preliminary, the research by civil and environmental engineering professor Liv Haselbach of Washington State University re-emphasizes findings first observed nearly half a century ago--that carbon-based chemical compounds may form in concrete in addition to the mineral calcite-now in the light of current efforts to stem global warming.

"Even though these chemical species may equate to only five percent of the CO2 byproduct from cement production, when summed globally they become significant," said Haselbach. "Concrete is the most-used building material in the world"......... Posted by: Tyler      Read more         Source

May 18, 2009, 5:38 AM CT

Detecting single atoms

Researchers have devised a new technique for real-time detection of freely moving individual neutral atoms that is more than 99.7% accurate and sensitive enough to discern the arrival of a single atom in less than one-millionth of a second, about 20 times faster than the best prior methods.

The system, described in Advance Online Publication at the Nature Physics web site by scientists at the Joint Quantum Institute (JQI) in College Park, MD, and the Universidad de Concepcin in Chile, employs a novel means of altering the polarization of laser light trapped between two highly-reflective mirrors, in effect letting the researchers "see" atoms passing through by the individual photons that they scatter.

The ability to detect single atoms and molecules is essential to progress in a number of areas, including quantum information research, chemical detection and biochemical analysis.

"Existing protocols have been too slow to detect moving atoms, making it difficult to do something to them before they are gone. Our work relaxes that speed constraint," says coauthor David Norris of JQI. "Moreover, it is hard to distinguish between a genuine detection and a random 'false positive' without collecting data over a large period of time. Our system both filters the signal and reduces the detection time"......... Posted by: Kevin      Read more         Source

May 18, 2009, 5:27 AM CT

Biological particles in high-altitude clouds

A team of atmospheric chemists has moved closer to what's considered the "holy grail" of climate change science: the first-ever direct detections of biological particles within ice clouds.

The team, led by Kimberly Prather and Kerri Pratt of the University of California at San Diego, Scripps Institution of Oceanography, sampled water droplet and ice crystal residues at high speeds while flying through clouds in the skies over Wyoming.

Analysis of the ice crystals revealed that the particles that started their growth were made up almost entirely of either dust or biological material such as bacteria, fungal spores and plant material.

While it has long been known that microorganisms become airborne and travel great distances, this study is the first to yield direct data on how they work to influence cloud formation.

Results of the Ice in Clouds Experiment - Layer Clouds (ICE-L), funded by the National Science Foundation (NSF), appear May 17 in the advance online edition of the journal Nature Geoscience

"If we understand the sources of the particles that nucleate clouds, and their relative abundance, we can determine their impact on climate," said Pratt, main author of the paper.

The effects of tiny airborne particles called aerosols on cloud formation have been some of the most difficult aspects of weather and climate for researchers to understand......... Posted by: Tyler      Read more         Source

May 14, 2009, 9:48 PM CT

Climate Change And Lake Baikal's Unique Biota

Siberia's Lake Baikal, the world's largest and most biologically diverse lake, faces the prospect of severe ecological disruption as a result of climate change, as per an analysis by a joint US-Russian team in the recent issue of BioScience. The lake is considered a treasure trove for biologists and was designated a World Heritage Site by UNESCO because a high proportion of its rich fauna and flora are found nowhere else. Perhaps the most alarming imminent threat stems from the dependence of the lake's food web on large, endemic diatoms, which are uniquely vulnerable to expected reductions in the length of time the lake is frozen each winter.

The article was written by Marianne V. Moore, of Wellesley College in Massachusetts, and five coauthors, including four from Irkutsk State University in Russia. Moore and his colleagues note that Lake Baikal's climate has become measurably milder over recent decades, and that annual precipitation is expected to increase. The average ice depth in the lake is known to have decreased in recent decades, and the ice-free season to have increased. Changes in the lake's food-web composition have been documented.

Future shortening in the duration of ice cover is expected to curtail the growth of the lake's endemic diatoms, because unlike most diatoms, they bloom under the ice in springtime and are highly dependent on ice cover for their reproduction and growth. The diatoms constitute the principal food of tiny crustaceans abundant in the lake, and these are in turn preyed upon by the lake's fish. Moreover, the crustaceans could be affected by changes in the transparency of the ice, an expected result of shifting precipitation patterns and changes in wind dynamics......... Posted by: Tyler      Read more         Source

May 14, 2009, 9:36 PM CT

Shift in Simulation Superiority

Science and engineering are advancing rapidly in part due to ever more powerful computer simulations, yet the most advanced supercomputers require programming skills that all too few U.S. scientists possess. At the same time, affordable computers and committed national programs outside the U.S. are eroding American competitiveness in number of simulation-driven fields.

These are some of the key findings in the International Evaluation of Research and Development in Simulation-Based Engineering and Science, released on Apr. 22, 2009, by the World Technology Assessment Center (WTEC).

"The startling news was how quickly our assumptions have to change," said Phillip Westmoreland, program director for combustion, fire and plasma systems at the National Science Foundation (NSF) and one of the sponsors of the report. "Because computer chip speeds aren't increasing, hundreds and thousands of chips are being ganged together, each one with a number of processors. New ways of programming are necessary".

Like other WTEC studies, this study was led by a team of leading scientists from a range of simulation science and engineering disciplines and involved site visits to research facilities around the world.

The nearly 400-page, multi-agency report highlights several areas in which the U.S. still maintains a competitive edge, including the development of novel algorithms, but also highlights endeavors that are increasingly driven by efforts in Europe or Asia, such as the creation and simulation of new materials from first principles......... Posted by: Kevin      Read more         Source

May 14, 2009, 9:32 PM CT

What Caused Earth's Earliest Ice Age?

An international team of geologists may have uncovered the answer to an age-old question - an ice-age-old question, that is. It appears that Earth's earliest ice age may have been due to the rise of oxygen in Earth's atmosphere, which consumed atmospheric greenhouse gases and chilled the earth.

Researchers from the University of Maryland, including post-doctoral fellows Boswell Wing and Sang-Tae Kim, graduate student Margaret Baker, and professors Alan J. Kaufman and James Farquhar, along with colleagues in Gera number of, South Africa, Canada and the United States, uncovered evidence that the oxygenation of Earth's atmosphere - generally known as the Great Oxygenation Event - coincided with the first widespread ice age on the planet.

"We can now put our hands on the rock library that preserves evidence of irreversible atmospheric change," said Kaufman. "This singular event had a profound effect on the climate, and also on life."

Using sulfur isotopes to determine the oxygen content of ~2.3 billion year-old rocks in the Transvaal Supergroup in South Africa, they found evidence of a sudden increase in atmospheric oxygen that broadly coincided with physical evidence of glacial debris, and geochemical evidence of a new world-order for the carbon cycle......... Posted by: Tyler      Read more         Source

May 14, 2009, 5:25 AM CT

Sediments that result from natural petroleum seeps

A newly released study by scientists at Woods Hole Oceanographic Institution (WHOI) and the University of California, Santa Barbara (UCSB) is the first to quantify the amount of oil residue in seafloor sediments that result from natural petroleum seeps off Santa Barbara, California.

The newly released study shows the oil content of sediments is highest closest to the seeps and tails off with distance, creating an oil fallout shadow. It estimates the amount of oil in the sediments down current from the seeps to be the equivalent of approximately 8-80 Exxon Valdez oil spills.

The paper is being reported in the May 15 issue of Environmental Science & Technology.

"Farwell developed and mapped out our plan for collecting sediment samples from the ocean floor," said WHOI marine chemist Chris Reddy, referring to main author Chris Farwell, at the time an undergraduate working with UCSB's Dave Valentine. "After conducting the analysis of the samples, we were able to make some spectacular findings".

There is an oil spill everyday at Coal Oil Point (COP), the natural seeps off Santa Barbara, California, where 20-25 tons of oil have leaked from the seafloor each day for the last several hundred thousand years.

Earlier research by Reddy and Valentine at the site observed that microbes were capable of degrading a significant portion of the oil molecules as they traveled from the reservoir to the ocean bottom and that once the oil floated to sea surface, about 10 percent of the molecules evaporated within minutes......... Posted by: Tyler      Read more         Source

May 12, 2009, 10:12 PM CT

Global warming driving Michigan mammals north

Some Michigan mammal species are rapidly expanding their ranges northward, apparently in response to climate change, a new study shows. In the process, these historically southern species are replacing their northern counterparts.

The finding, by researchers at the University of Michigan, Michigan State University and Ohio's Miami University, appears in the recent issue of the journal Global Change Biology.

"When you read about changes in flora and fauna related to climatic warming, most of what you read is either predictive-they're talking about things that are going to happen in the future-or it's restricted to single species living in extreme or remote environments, like polar bears in the Arctic," said lead author Philip Myers, professor of ecology and evolutionary biology at U-M. "But this study documents things that are happening right now, here at home".

What will be the ultimate impact of Michigan's changing mammal communities?

"We're talking about the commonest mammals there, mammals that have considerable ecological impact," Myers said. "They disperse seeds, they eat seeds, they eat the insects that kill trees, they disperse the fungus that grows in tree roots that is necessary for trees to grow, and they're the prey base for a huge number of carnivorous birds, mammals and snakes. But we don't know enough about their natural history to know whether replacing a northern species with a southern equivalent is going to pass unnoticed or is going to be catastrophic. It could work either way......... Posted by: Tyler      Read more         Source

May 12, 2009, 5:26 AM CT

Green renovations in existing US schools

Going green with new construction is a good idea, but what about renovating existing structures? Like, say, the 20 billion square feet of existing U.S. public schools, 40 percent of which have 15 million students in poor environmental conditions?

These are questions at the heart of research by Ihab M.K. Elzeyadi, a professor of architecture at the University of Oregon. Elzeyadi has completed the first stage of creating a Green Classroom Toolbox for architects and planners to use in their energy retrofits and modernization plans. His second of three presentations in a three-month period will be May 13 during Solar 2009, the 38th national meeting of the American Solar Energy Society, in Buffalo, N.Y.

"We believe our findings can help plan classroom designs and retrofits to green our aging schools, which are energy and environmentally unconscious," said Elzeyadi, who also is a participating faculty member in the Oregon Built Environment & Sustainable Technologies Center (Oregon BEST), an independent, nonprofit organization established by the Oregon Legislature in 2007.

"Under the American Recovery and Reinvestment Act of 2009, school districts will have access to federal funding to modernize and green their schools," he said. "Our work provides school designers and officials with the needed guidelines to direct this process the right way."It will act as a decision support system"......... Posted by: Tyler      Read more         Source

May 12, 2009, 5:22 AM CT

West coast areas most affected by humans

Climate change, fishing, and commercial shipping top the list of threats to the ocean off the West Coast of the United States.

"Every single spot of the ocean along the West Coast," said Ben Halpern, a marine ecologist at the National Center for Ecological Analysis and Synthesis (NCEAS) at the University of California, Santa Barbara, "is affected by 10 to 15 different human activities annually".

In a two-year study to document the way humans are affecting the oceans in this region, Halpern and his colleagues overlaid data on the location and intensity of 25 human-derived sources of ecological stress, including climate change, commercial and recreational fishing, land-based sources of pollution, and ocean-based commercial activities.

With the information, they produced a composite map of the status of West Coast marine ecosystems.

The work was published online today in the journal Conservation Letters, and was conducted at NCEAS. NCEAS is primarily funded by NSF's Division of Environmental Biology.

"This important analysis of the geography and magnitude of land-based stressors should help focus attention on the hot-spots where coordinated management of land and ocean activities is needed," said Phillip Taylor, section head in NSF's Division of Ocean Sciences......... Posted by: Tyler      Read more         Source

May 7, 2009, 10:16 PM CT

Cutting cattle methane

Beef farmers can breathe easier thanks to University of Alberta scientists who have developed a formula to reduce methane gas in cattle.

By developing equations that balance starch, sugar, cellulose, ash, fat and other elements of feed, a Canada-wide team of researchers has given beef producers the tools to lessen the methane gas their cattle produce by as much as 25 per cent.

"That's good news for the environment," said Stephen Moore, a professor of agricultural, food and nutritional science at the University of Alberta in Canada. "Methane is a greenhouse gas, and in Canada, cattle account for 72 per cent of the total emissions. By identifying factors such as diet or genetics that can reduce emissions, we hope to give beef farmers a way to lessen the environmental footprint of their cattle production and methane reductions in the order of 25 per cent are certainly achievable".

Using information from prior studies, the scientists compiled an extensive database of methane production values measured on cattle and were able to formulate equations to predict how much methane a cow would produce based on diet.

The study was jointly conducted with the universities of Guelph and Manitoba, Agriculture and Agri-Food Canada and the International Atomic Energy Agency in Austria. It published recently in the Journal of Animal Science........ Posted by: Tyler      Read more         Source

May 5, 2009, 5:17 AM CT

Clues for self-cleaning materials

Self-cleaning walls, counter tops, fabrics, even micro-robots that can walk on water -- all those things and more could be closer to reality because of research recently completed by researchers at the University of Nebraska-Lincoln and at Japan's RIKEN institute.

Humans have marveled for millennia at how water beads up and rolls off flowers, caterpillars and some insects, and how insects like water striders are able to walk effortlessly on water. It's a property called super hydrophobia and it's been examined seriously by researchers since at least the 1930s.

"A lot of people study this and engineers particularly like the water strider because it can walk on water," said Xiao Cheng Zeng, Ameritas university professor of chemistry at UNL. "Their legs are super hydrophobic and each leg can hold about 15 times their weight. 'Hydrophobic' means water really doesn't like their legs and that's what keeps them on top. A lot of researchers and engineers want to develop surfaces that mimic this from nature".

In a paper to be reported in the May 4-8 online edition of the Proceedings of the National Academy of Sciences, Zeng and his Japanese colleagues, Takahiro Koishi of the University of Fukui and RIKEN, Kenji Yasuoka of Keio University, and Shigenori Fujikawa and Toshikazu Ebisuzaki of RIKEN, give engineers and materials researchers important clues in how to develop the long-sought super hydrophobic materials......... Posted by: Kevin      Read more         Source

May 5, 2009, 5:14 AM CT

Particles, molecules prefer not to mix

In the world of small things, shape, order and orientation are surprisingly important, as per findings from a newly released study by chemists at Washington University in St. Louis.

Lev Gelb, WUSTL associate professor of chemistry, his graduate student Brian Barnes, and postdoctoral researcher Daniel Siderius, used computer simulations to study a very simple model of molecules on surfaces, which looks a lot like the computer game "Tetris." They have observed that the shapes in this model (and in the game) do many surprising things.

"First, different shapes don't mix very well with each other; each shape prefers to associate with others of the same kind," Gelb says. "When you put a lot of different shapes together, they separate from each other on microscopic scales, forming little clusters of nearly pure fluids. This is true even for the mirror-image shapes.

"Second, the structures of the pure (single-shape) fluids are quite complex and not what we might have predicted. There is a very strong tendency for some of the shapes, like rods and S- and Z- shapes, to align in the same direction. Finally, how `different looking' the shapes are isn't a good predictor for how well they mix; it turns out that the hard-to-predict characteristic structures of the fluids are more important than the shapes themselves, in this regard."........ Posted by: Kevin      Read more         Source

May 4, 2009, 5:16 AM CT

Nanotechnology holds promise

Yale scientists describe a breakthrough in safe and effective administration of potential antiviral drugs small interfering RNA (siRNA) molecules that silence genes the first step in development of a new kind of therapy for sexually transmitted diseases (STDs). The work is reported May 4 as an advance online publication of Nature Materials

"RNA interference is a promising approach for prevention and therapy of human disease," said main author Kim Woodrow, Yale postdoctoral fellow in Yale's School of Engineering & Applied Science. "We wanted to develop a new strategy of delivering siRNAs with a FDA-approved material".

As their name suggests, siRNAs interfere and knock out the function of genes in higher organism as well as in microbes that may cause STDs. The scientists designed siRNAs to target a gene expressed widely in the lining of the female mouse reproductive tract, in this proof-of-principle work.

Using densely-loaded nanoparticles made of a biodegradable polymer known as PLGA, the scientists created a stable "time release" vehicle for delivery of siRNAs to sensitive mucosal tissue like that of the female reproductive system.

They observed that the particles, loaded with the drug agent, moved effectively in two important ways, penetrating to reach cells below the surface of the mucosa and distributing throughout the vaginal, cervical, and uterine regions. Furthermore, the siRNAs stayed in the tissues for at least a week and knockdown of gene activity lasted up to 14 days......... Posted by: Kevin      Read more         Source

May 1, 2009, 5:22 AM CT

Glacial Advances

The vast majority of the world's glaciers are retreating as the planet gets warmer. But a few, including glaciers south of the equator in South America and New Zealand, are inching forward.

A paper in this week's issue of the journal Science puts this enigma in perspective; for the last 7,000 years, New Zealand's largest glaciers have often moved out of step with glaciers in the Northern Hemisphere, pointing to strong regional variations in climate.

"This research should provide much more accurate reconstructions of glacial advances worldwide, allowing us in turn to make climate models more accurate," said Paul Filmer, program director in the National Science Foundation's (NSF) Division of Earth Sciences, which funded the research.

Conventional wisdom holds that during the era of human civilization, climate has been relatively stable. The newly released study is the latest to challenge this view, by showing that New Zealand's glaciers have gone through rapid periods of growth and decline during the current interglacial period known as the Holocene.

"New Zealand's mountain glaciers have fluctuated frequently over the last 7,000 years, and glacial advances have become slightly smaller through time," said Joerg Schaefer, main author of the paper and a geochemist at Columbia University's Lamont-Doherty Earth Observatory......... Posted by: Tyler      Read more         Source

April 30, 2009, 5:50 PM CT

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Nureach Global offers through its SEO Services a broad variety of services. These include unlimited e-mail or phone customer support, submission to local & international search engines/directories, current performance & monthly SEO reports, Google (XML)/Yahoo & MSN sitemap creation, Google product search feeds, image & hyperlink optimization, working on html source code, title & Meta tag optimization, manual link requests to related sites, internal link analysis & broken link checker, content writing, and keyword research. These services boosted up my targeted visitors. A large proportion of conversations were converted into deals. TrustRank and Google PageRank of my website were thereby increased. Number of incoming links was multiplied as well. More and more search engines were crawling through and indexing my website with each passing day. I also got higher website rankings for my targeted keywords on search engines like Yahoo, Google, and MSN, and others. The initiative taken by Nureach Global all lead to an increased return-on-investment. I now proudly compete with greater business houses. This has been possible because Search Engine Optimization has exposed my business, products, services, and website to millions of potential customers across the globe. I must confess that this has been one of the wisest choices I have made in promoting my website. I suggest you all adopt the same. I am sure you won't regret you investment......... Posted by: Kevin      Read more         Source

April 29, 2009, 5:16 AM CT

Match between molecular, fossil data

During a seminar at another institution several years ago, University of Chicago paleontologist David Jablonski fielded a hostile question: Why bother classifying organisms as per their physical appearance, let alone analyze their evolutionary dynamics, when molecular techniques had already invalidated that approach?

With more than a few heads in the audience nodding their agreement, Jablonski, the William Kenan Jr. Professor in Geophysical Sciences, saw more work to be done. The question launched him on a rigorous study that has culminated in a new approach to reconciling the conflict between fossil and molecular data in evolutionary studies.

For more than two decades, debate has waxed and waned between biologists and paleontologists about the reliability of their different methods. Until now, attention has focused on the dramatically different evolutionary history of certain lineages as determined by fossils or by genetics.

Researchers using molecular techniques assert that genetics more accurately determines evolutionary relationships than does a comparison of physical characteristics preserved in fossils. But how inaccurate, really, were the fossils? Jablonski and the University of Michigan's John A. Finarelli have published the first quantitative evaluation of these assumed discrepancies in the Proceedings of the National Academy of Sciences........ Posted by: William      Read more         Source

April 29, 2009, 5:14 AM CT

Discovery of early African mammal fossils

A limestone countertop, a practiced eye and Google Earth all played roles in the discovery of a trove of fossils that may shed light on the origins of African wildlife.

The circuitous and serendipitous story, featuring University of Michigan paleontologists Philip Gingerich, Gregg Gunnell and Bill Sanders, is the subject of a segment on the award-winning television series "Wild Chronicles," currently airing on public television stations (Episode 412-Looking Back; check listings for local air dates). "Wild Chronicles" is produced by National Geographic Television and presented by WLIW21 in association with WNET.ORG.

The saga began when Gingerich, an authority on ancient whales, learned of a whale fossil from Egypt that had been discovered in a most unconventional way. At a stonecutting yard in Italy where blocks of stone from around the world are sliced up for countertops, masons had noticed what looked like cross-sections of a skeleton in slabs cut from a huge hunk of limestone imported from Egypt. Paleontologist Giovanni Bianucci of the University of Pisa recognized these as fossilized remains of a whale that lived in Egypt 40 million years ago, when the region was covered by ocean.

His curiosity piqued by the discovery, Gingerich wanted to visit the site where the limestone was quarried, but the exact location was something of a mystery. Bianucci had reported that the countertop whale came from a site near the Egyptian city of Sheikh Fadl, but a colleague in Egypt told Gingerich the quarry was probably farther east-exactly where, he wasn't sure......... Posted by: William      Read more         Source

April 29, 2009, 5:04 AM CT

'Chevrons' are not evidence of megatsunamis

A persistent school of thought in recent years has held that so-called "chevrons," large U- or V-shaped formations found in some of the world's coastal areas, are evidence of megatsunamis caused by asteroids or comets slamming into the ocean.

University of Washington geologist and tsunami expert Jody Bourgeois has a simple response: Nonsense.

The term "chevron" was introduced to describe large dunes shaped something like the stripes you might see on a soldier's uniform that are hundreds of meters to a kilometer in size and were originally found in Egypt and the Bahamas.

But the discovery of similar forms in Australia and Madagascar led some researchers to theorize that they were, in fact, deposits left by huge tsunami waves, perhaps 10 times larger than the devastating Indian Ocean tsunami of December 2005.

Such huge waves, they suggest, would result from the giant splash of an asteroid or comet hitting the ocean. They also suggest one such impact occurred 4,800 to 5,000 years ago, and that chevrons in Australia and Madagascar point to its location in the Indian Ocean.

But Bourgeois said the theory just doesn't hold water.

For example, she said, there are numerous chevrons on Madagascar, but a number of are parallel to the coastline. Models created by Bourgeois' colleague Robert Weiss show that if they were created by tsunamis they should point in the direction the waves were travelling, mostly perpendicular to the shore......... Posted by: Tyler      Read more         Source

April 27, 2009, 5:21 AM CT

How to catch the lightwave?

New Haven, Conn. As scientists push towards detection of single molecules, single electron spins and the smallest amounts of mass and movement, Yale scientists have demonstrated silicon-based nanocantilevers, smaller than the wavelength of light, that operate on photonic principles eliminating the need for electric transducers and expensive laser setups.

The work reported in an April 26 advance online publication of Nature Nanotechnology ushers in a new generation of tools for ultra-sensitive measurements at the atomic level.

In nanoelectromechanical systems (NEMS), cantilevers are the most fundamental mechanical sensors. These tiny structures fixed at one end and free at the other act like nano-scale diving boards that "bend" when molecules "jump" on them and register a change that can be measured and calibrated. This paper demonstrates how NEMS can be improved by using integrated photonics to sense the cantilever motion.

"The system we developed is the most sensitive available that works at room temperature. Previously this level of sensitivity could only be achieved at extreme low temperatures" said senior author Hong Tang, assistant professor of electrical and mechanical engineering in the Yale School of Engineering and Applied Sciences......... Posted by: Kevin      Read more         Source

April 27, 2009, 5:13 AM CT

Did dinosaurs die from an asteroid hit?

The enduringly popular theory that the Chicxulub crater holds the clue to the demise of the dinosaurs, along with some 65 percent of all species 65 million years ago, is challenged in a paper to be reported in the Journal of the Geological Society on April 27, 2009.

The crater, discovered in 1978 in northern Yucutan and measuring about 180 kilometers (112 miles) in diameter, records a massive extra-terrestrial impact.

When spherules from the impact were found just below the Cretaceous-Tertiary (K-T) boundary, it was quickly identified as the "smoking gun" responsible for the mass extinction event that took place 65 million years ago.

It was this event which saw the demise of dinosaurs, along with countless other plant and animal species.

However, many researchers have since disagreed with this interpretation.

The newest research, led by Gerta Keller of Princeton University in New Jersey, and Thierry Adatte of the University of Lausanne, Switzerland, uses evidence from Mexico to suggest that the Chicxulub impact predates the K-T boundary by as much as 300,000 years.

"Keller and his colleagues continue to amass detailed stratigraphic information supporting new thinking about the Chicxulub impact, and the mass extinction at the end of the Cretaceous," says H. Richard Lane, program director in the National Science Foundation (NSF)'s Division of Earth Sciences, which funded the research. "The two may not be linked after all"......... Posted by: William      Read more         Source

April 24, 2009, 5:14 AM CT

What makes a cow a cow?

Scientists report today in the journal Science that they have sequenced the bovine genome, for the first time revealing the genetic features that distinguish cattle from humans and other mammals.

The six-year effort involved an international consortium of scientists and is the first full genome sequence of any ruminant species. Ruminants are distinctive in that they have a four-chambered stomach that with the aid of a multitude of resident microbes allows them to digest low quality forage such as grass.

The bovine genome consists of at least 22,000 protein-coding genes and is more similar to that of humans than to the genomes of mice or rats, the scientists report. However, the cattle genome appears to have been significantly reorganized since its lineage diverged from those of other mammals, said University of Illinois animal sciences professor Harris Lewin, whose lab created the high-resolution physical map of the bovine chromosomes that was used to align the sequence. Lewin, who directs the Institute for Genomic Biology, also led two teams of scientists on the sequencing project and is the author of a Perspective article in Science on the bovine genome sequence and an accompanying study by the Bovine Genome and Analysis Consortium.

"Among the mammals, cattle have one of the more highly rearranged genomes," Lewin said. "They seem to have more translocations and inversions (of chromosome fragments) than other mammals, such as cats and even pigs, which are closely correlation to cattle......... Posted by: Ashley      Read more         Source

April 24, 2009, 5:10 AM CT

Forest fires and global warming

Fire's potent and pervasive effects on ecosystems and on a number of Earth processes, including climate change, have been underestimated, as per a new report.

"We've estimated that deforestation due to burning by humans is contributing about one-fifth of the human-caused greenhouse effect -- and that percentage could become larger," said co-author Thomas W. Swetnam of The University of Arizona in Tucson.

"It's very clear that fire is a primary catalyst of global climate change," said Swetnam, director of UA's Laboratory of Tree-Ring Research.

"The paper is a call to arms to earth researchers to investigate and better evaluate the role of fire in the Earth system," he said.

The team also reports that all fires combined release an amount of carbon dioxide into the atmosphere equal to 50 percent of that coming from the combustion of fossil fuels.

"Fires are obviously a main responses to climate change, but fires are not only a response -- they feed back to warming, which feeds more fires," Swetnam said.

When vegetation burns, the resulting release of stored carbon increases global warming. The more fires, the more carbon dioxide released, the more warming -- and the more warming, the more fires.

The very fine soot, known as black carbon, that is released into the atmosphere by fires also contributes to warming......... Posted by: Tyler      Read more         Source

April 23, 2009, 5:09 AM CT

Self-healing concrete for safer infrastructure

A concrete material developed at the University of Michigan can heal itself when it cracks. No human intervention is necessary-just water and carbon dioxide.

A handful of drizzly days would be enough to mend a damaged bridge made of the new substance. Self-healing is possible because the material is designed to bend and crack in narrow hairlines rather than break and split in wide gaps, as traditional concrete behaves.

"It's like if you get a small cut on your hand, your body can heal itself. But if you have a large wound, your body needs help. You might need stitches. We've created a material with such tiny crack widths that it takes care of the healing by itself. Even if you overload it, the cracks stay small," said Victor Li, the E. Benjamin Wylie Collegiate Professor of Civil Engineering and a professor of Materials Science and Engineering.

A paper about the material is published online in Cement and Concrete Research. It will be printed in a forthcoming edition of the journal.

In Li's lab, self-healed specimens recovered most if not all of their original strength after scientists subjected them to a 3 percent tensile strain. That means they stretched the specimens to 3 percent beyond their initial size. It's the equivalent of stretching a 100-foot piece an extra three feet-enough strain to severely deform metal or catastrophically fracture traditional concrete......... Posted by: Kevin      Read more         Source

April 22, 2009, 10:13 PM CT

Plants could override climate change effects on wildfires

Scientists predict that global climate change will make many regions around the world warmer and drier, a factor which, taken by itself, would seem to increase the risk of wildfires.

But a new study led by a Montana State University researcher shows that changes in the types of vegetation covering an area play a major role in determining how often that area is burned by fires and could even counteract the effects of changes in temperature and moisture.

In the study, MSU earth sciences post-doctoral researcher Philip Higuera and his colleagues show that the risk of wildfires can be either reduced or increased by changes in the distribution and abundance of plants. The study would be published in the recent issue of the journal Ecological Monographs.

"Climate affects vegetation, vegetation affects fire and both fire and vegetation respond to climate change," Higuera said. "Our work emphasizes the need to consider the multiple drivers of fire regimes when we anticipate how they will respond to climate change".

Higuera and his colleagues studied fire history in northern Alaska by analyzing sediments at the bottom of lakes, some dating as far back as 15,000 years. In the samples from the lakes, the scientists measured the abundance of different preserved plant parts, such as pollen, to determine what types of vegetation dominated the region in the past. Like rings in a tree, different sediment layers represent different times in the past......... Posted by: Tyler      Read more         Source

April 22, 2009, 5:23 AM CT

New technique may lead to sharper images

When photographers zoom in on an object to see it better, they lose the wide-angle perspective -- they are forced to trade off "big picture" context for detail. But now an imaging method developed by Princeton scientists could lead to lenses that show all parts of the scene at once in the same high detail. The new method could help build more powerful microscopes and other optical devices.

"It allows you to take a closer look at an object without narrowing your field of view," said Jason Fleischer, an assistant professor of electrical engineering at Princeton who led the research. The study, co-written with graduate students Christopher Barsi and Wenjie Wan, is reported as the cover story in the April edition of Nature Photonics

Cameras and other optical devices -- including the human eye -- are limited by the amount of light that they can collect through their lens openings, or apertures. In order for a light ray to be recorded, it has to pass through the lens and reach the device's "detector" -- such as the eye's retina or a digital camera's detector. But a number of light rays never make it to the detector, either because they are too weak, or because they are deflected.

This problem is especially acute with details that are smaller than the wavelength of light. (Each color of light has a distinct wavelength -- green, for instance, has a wavelength of 530 nanometers, roughly the size of a typical bacterium's internal structure.) Light rays from such tiny features fade before they reach the lens. To capture these rays, devices have to probe very near the surface of the object, and scan it point-by-point, stitching together a full image......... Posted by: Kevin      Read more         Source

April 20, 2009, 9:59 PM CT

Is it going to rain today?

If Mark Twain were alive today he might rephrase his frequently cited observation about everyone talking about the weather but not doing anything about it to say, "Everyone reads or watches weather forecasts, but a number of people don't understand them."

He'd do that because new research indicates that only about half the population knows what a forecast means when it predicts a 20 percent chance of rain, as per scientists at the University of Washington.

Writing in the Bulletin of the American Meteorological Society, the scientists said the confusion comes because people don't understand what the 20 percent chance of rain actually refers to. A number of people think it means that it will rain over 20 percent of the area covered by the forecast or for 20 percent of the time period covered by the forecast, said Susan Joslyn, a UW cognitive psychology expert and senior lecturer.

"When a forecast says there is 20 percent chance of rain tomorrow it actually means it will rain on 20 percent of the days with exactly the same atmospheric conditions," she said. "With the exception of the probability of precipitation, most weather forecasts report a single value such as the high temperature will be 53 degrees. This is deterministic because it implies that forecasters are sure the high temperature will be 53 degrees. But forecasting is probabilistic and 53 degrees is in the middle of the range of possible temperatures, say 49 to 56 degrees."........ Posted by: Tyler      Read more         Source

April 20, 2009, 9:51 PM CT

Cuts in Greenhouse Gas Emissions Would Save Arctic Ice

The threat of global warming can still be greatly diminished if nations cut emissions of heat-trapping greenhouse gases by 70 percent this century, as per a new analysis. While global temperatures would rise, the most dangerous potential aspects of climate change, including massive losses of Arctic sea ice and permafrost and significant sea level rise, could be partially avoided.

The study, led by researchers at the National Center for Atmospheric Research (NCAR), will be published next week in Geophysical Research Letters. It was funded by the Department of Energy and the National Science Foundation, NCAR's sponsor.

"This research indicates that we can no longer avoid significant warming during this century," says NCAR scientist Warren Washington, the main author. "But if the world were to implement this level of emission cuts, we could stabilize the threat of climate change and avoid catastrophe".

Average global temperatures have warmed by close to 1 degree Celsius (almost 1.8 degrees Fahrenheit) since the pre-industrial era. Much of the warming is due to human-produced emissions of greenhouse gases, predominantly carbon dioxide. This heat-trapping gas has increased from a pre-industrial level of about 284 parts per million (ppm) in the atmosphere to more than 380 ppm today......... Posted by: Tyler      Read more         Source

April 20, 2009, 9:40 PM CT

West African Droughts are the Norm

Listen to an audio file of Timothy Shanahan, Jonathan Overpeck and Paul Filmer discussing the findings with reporters.

A newly released study of lake sediments in Ghana suggests that severe droughts lasting several decades, even centuries, were the norm in West Africa over the past 3,000 years.

The earlier dry spells dwarfed the well-documented drought that plagued West Africa in the late-20th century, and as the planet warms, the study's authors believe the region's rainfall patterns will have an even greater impact.

The team of georesearchers and climate scientists, led by Jonathan Overpeck of the University of Arizona and his former doctoral student, main author Timothy Shanahan, who is now at the University of Texas (UT) at Austin, announced their findings in the April 17, 2009, issue of Science.

Because of close agreement amongst several data sets, the researchers believe the droughts are driven in part by circulation of the ocean and atmosphere in and above the Atlantic--and possibly beyond. If climate models for such circulation patterns hold true, the study suggests global warming could create conditions that favor extreme droughts.

"Clearly, much of West Africa is already on the edge of sustainability," says Overpeck, "and the situation could become much more dire in the future with increased global warming"......... Posted by: Tyler      Read more         Source