August 8, 2007, 8:42 PM CT

Conventional plowing is 'skinning our agricultural fields'

Traditional plow-based agricultural methods and the need to feed a rapidly growing world population are combining to deplete the Earth's soil supply, a new study confirms.

In fact, long-established practices appear to increase soil erosion to the point that it is not offset by soil creation, said David Montgomery, a University of Washington professor of Earth and space sciences.

No-till agriculture, in which crop stubble is mixed with the top layer of soil using a method called disking, is far more sustainable, he said.

"Soil loss through conventional agriculture is in a range of 10 to 100 times greater than the rate at which soil is created. No-till agriculture brings it into the ballpark, surprisingly close to being balanced with soil creation," he said.

Montgomery looked at data from more than 1,650 measurements published in more than 200 studies examining various aspects of farming practices, soil creation and erosion. His findings are being published this week in the online edition of the Proceedings of the National Academy of Sciences, and will be published in a print edition later in the year.

Long-term erosion rates worldwide average less than one-tenth of a millimeter per year, which is similar to the rate at which soil is produced through mechanical, chemical and biological processes that dissolve rock and mix the grains with organic matter. The research shows that erosion rates consistently exceed 1 millimeter a year less than a half-inch per decade only in steep alpine terrain, and plowed fields erode at about the same pace as the Himalayas, home to the highest mountain peaks in the world......... Posted by: Tyler      Read more         Source

August 7, 2007, 10:43 PM CT

Stability and Diversity in Ecosystems

Is biodiversity important for predicting human impacts on ecosystems? If diverse ecosystems were as a consequence more stable, the answer would be yes.

However, stability is not one, simple property of an ecosystem and there is no one, simple relationship between diversity and stability, say ecologists Tony Ives and Steve Carpenter of the University of Wisconsin at Madison.

In the last 20 years, ecologists have performed experiments on diversity and stability, manipulating diversity (number of species) at small scales, then measuring one of several kinds of stability.

While these studies have taught us a lot about how diversity affects some types of stability, they don't necessarily tell us how stable ecosystems will be against human impacts, say Ives and Carpenter.

Ecologists should turn the question on its head, the scientists believe: rather than focusing on how diversity affects stability, researchers might make faster progress by focusing on stability first.

"Humans don't change 'just' biodiversity," said Ives. "Humans cause major environmental changes to ecosystems, like acidifying lakes or cutting down forests, with changes in biodiversity often a by-product.

"Rather than how biodiversity affects stability, we should be asking how environmental change affects the stability of a number of aspects of ecosystems, including diversity"......... Posted by: Tyler      Read more         Source

August 7, 2007, 10:35 PM CT

Where chemistry happens for the very first time

Picture a cool place, teeming with a multitude of hot bodies twirling about in rapidly changing formations of singles and couples, partners and groups, constantly dissolving and reforming.

If you were thinking of the dance floor in a modern nightclub, think again.

It's a description of the shells around dying stars, the place where newly formed elements make compounds and life takes off, said Katharina Lodders, Ph.D., research associate professor of earth and planetary sciences in Arts & Sciences at Washington University in St. Louis.

Chemistry for the very first time

"The circumstellar environment is where chemistry happens for the very first time," said Lodders. "It's the first place a newly synthesized element can do chemistry. It's a supermarket of things from dust to gas and dust grains to molecules and atoms. The circumstellar shells enable a chemistry that produced grains older than our sun itself. It's generated some popular interest, and this year marks the 20th anniversary of the presolar grain discoveries".

After the discovery of presolar diamonds in a meteorite in 1987 - the first stardust found in a meteorite - researchers at Washington University in St. Louis have been prominent in finding and analyzing pre-solar grains made of silicon carbide, diamonds, corundum, spinel, and silicates. The latest discovery - a silicate grain that formed around a foreign star and became incorporated into a comet in our solar system - was captured and returned by the STARDUST space mission in 2006......... Posted by: Sarah      Read more         Source

August 6, 2007, 5:50 PM CT

Old McDonald's has a hold on kids' taste buds

Say what you will, Shakespeare, but a McNugget by any other name is just not as tasty. At least, not to the 3- to 5-year-old set.

Asked to sample two identical foods from the fast-food giant McDonald's, children preferred the taste of the version branded with the restaurant's familiar "Golden Arches" to one extracted from unmarked paper packaging, say scientists at the Stanford University School of Medicine and Lucile Packard Children's Hospital.

The study shows that even young children are swayed by brand preferences. The results are likely to fuel more debate over a growing movement to restrict marketing to kids under 8 years old.

"Kids don't just ask for food from McDonald's," said Thomas Robinson, MD, director of the Center for Healthy Weight at Packard Children's and associate professor of pediatrics and of medicine at the School of Medicine. "They actually think that the chicken nugget they think is from McDonald's tastes better than an identical, unbranded nugget".

The degree of preference expressed by the children correlated with the number of television sets they had in their homes and the frequency with which they ate at McDonald's.

Numerous studies have shown that young children are unable to understand that advertising, product placement and co-branding with popular toys are meant to get them to choose one product over another. For them, "truth in advertising" has a very literal meaning......... Posted by: Sean      Read more         Source

August 6, 2007, 5:24 PM CT

Can hemp help the everglades?

Within Southern Florida, soil and water conditions indicate potential for leaching from the use of atrazine-based herbicides in corn crops. Researchers from USDA-Agricultural Research Service (ARS) and University of Florida conducted studies to evaluate the specific groundwater risk from atrazine use by focusing on a specific cover crop that seems to have the potential to greatly reduce that risk. The crop is called sunn hemp. Its a tall, herbaceous annual that grows rapidly to a height of 6 to 7 feet.

The regions aquifer provides drinkable water for nearly all of the rapidly growing population. Agricultural practices that impair water quality may also stunt a massive project intended to restore the Florida Everglades ecosystem. A number of investigations have shown that cover crops can reduce herbicide leaching; however groundwater quality has not been widely observed and the effectiveness of cover crops on water contamination has not been documented.

The studies revealed that atrazine and some of its products may seep into the groundwater and impair water quality. Climate, cropping patterns, high dilution rates, and high chemical degradation rates limited the contamination levels. Measurements also showed that cover crops significantly reduced contamination in groundwater. The studies focused on sweet corn production and included whether fields with a highly vigorous cover crop would reduce impacts. Sunn hemp planted during uncultivated summer periods was the most focused upon. Crops such as these can be effective in reducing weeds and leaching while enriching soil. Sunn hemp can be grown to prevent soil erosion, as high-protein forage, and in older plants, it can be used to make cloth, twine, and rope......... Posted by: Tyler      Read more         Source

August 6, 2007, 5:19 PM CT

Diagnostic 'lab on a chip'

If you have ever marveled over the orderly process by which cars, buses and other modes of transportation are directed toward their destinations in a big city, youll really appreciate the work of one Florida State University chemist.

Thomas Fischer, an associate professor of chemistry and biochemistry at FSU, is designing a smart traffic system similar to those in major metropolises. A major difference, though, is its size: Fischers traffic grid is small enough to fit on a tiny microchip.

Working with an FSU postdoctoral associate, Pietro Tierno, and another colleague, Professor Tom H. Johansen of the University of Oslo in Norway, Fischer has designed a lab on a chip -- a small device that, when exposed to very low magnetic fields, might one day be used as a portable tool for quickly diagnosing a variety of human illnesses.

Currently, a doctor seeking to help a sick patient may take a blood sample and send it out to a laboratory, Fischer said. In three or four days, the lab results will come back and the doctor will have a better idea of what ails the patient.

With the lab on a chip, however, it might be possible to take a single drop of the patients blood, place it on a small chip, and then be able to provide a very quick, inexpensive and -- most important -- accurate diagnosis......... Posted by: Kevin      Read more         Source

August 6, 2007, 5:13 PM CT

Tracking North American Climate Change

Gene Takle begins talks about climate change with some strong statements.

"There is no question now that the climate is changing on a global scale," says Takle, an Iowa State University professor of geological and atmospheric sciences and agronomy. "The evidence is so overwhelming".

But what does that mean on a smaller scale? How are greenhouse gases changing the climate in North America? In the United States? In Iowa?.

After all, "You and I are not affected by a few tenths of a degree of temperature change on a global scale," Takle said.

Takle is working with Bill Gutowski, an Iowa State professor of geological and atmospheric sciences, and Ray Arritt, an Iowa State professor of agronomy, to find some answers about regional climate change.

The three have worked together on climate studies for 15 years. And now they've joined an international group of researchers collaborating on the North American Regional Climate Change Assessment Program. The assessment program is led by Linda Mearns, a senior scientist at the National Center for Atmospheric Research in Boulder, Colo. The National Science Foundation is funding the Iowa State work on the project with a $353,000 grant.

The project calls for six teams of scientists (four from the United States, including the Iowa State group, one from Canada and one from Europe) to run their own regional climate models using at least two sets of identical data from two research groups studying global climate change. The research groups will see what their models say about regional climate change and compare the results. Ultimately, the scientists will create data sets that will help them study the impacts of climate change on a continental or even statewide scale......... Posted by: Tyler      Read more         Source

August 3, 2007, 10:27 PM CT

Sensors Help Africa Tackle Water Shortage

Zambian water authorities are integrating information based on satellite imagery to alleviate water shortages. With inadequate information causing a number of water-related problems, an ESA project has generated a variety of environmental maps to provide local policy makers with the necessary tools for effective water resource management.

As part of the IWAREMA (Integrated Water Resource management for Zambia) project, funded through ESA's Data User Element, data from ESA's multispectral MERIS sensor aboard Envisat was used to create maps depicting existing water resources, suitable dam locations and land cover. The project is carried out by the Belgium Company GIM (Geographic Information Management) in partnership with the University of Zambia and the Zambian water authorities.

"The results of the IWAREMA project can be used to protect Zambia's ecosystems especially in the Kafue flats where wildlife, agricultural activities, fisheries and tourism compete for regulated water resources," Jack Nkhoma of Zambia's Department of Water Affairs said.

Having access to these maps allows authorities to determine the expansion of urban areas and loss of forest and agricultural areas as well as calculate the risk of erosion, change in water availability and percentage of surface water, which will allow for early flood warnings......... Posted by: Tyler      Read more         Source

August 3, 2007, 10:24 PM CT

The Planet, the Galaxy and the Laser

On the night of 21 July, ESO astronomer Yuri Beletsky took images of the night sky above Paranal, the 2600m high mountain in the Chilean Atacama Desert home to ESO's Very Large Telescope. The amazing images bear witness to the unique quality of the sky, revealing not only the Milky Way in all its splendour but also the planet Jupiter and the laser beam used at Yepun, one of the 8.2-m telescopes that make up this extraordinary facility.

"The images are not composite", emphasises Yuri Beletsky. "The camera was being tracked on the stars, which can be easily noticed if you look at the telescope domes on the image (they look a little fuzzy). The colour of the laser beam on the first image actually looks pretty close to what one can see on the sky with the unaided eye."

Most striking in the images is the wide band of stars called the Milky Way. Spanning more than 100 degrees in the first of these images, it shows the dust and stars that are part of our own Galaxy, a spiral galaxy containing about 100 billion stars.

In the middle of this image, two bright objects are also seen. The brighter of the two is the planet Jupiter. The other is the bright star Antares. Another bright star, Alpha Centauri, one of the closest stellar neighbours to the Sun, is visible at the middle-left edge of the image......... Posted by: Brooke      Read more         Source

August 3, 2007, 10:20 PM CT

European heat waves double in length since 1880

The most accurate measures of European daily temperatures ever indicate that the length of heat waves on the continent has doubled and the frequency of extremely hot days has nearly tripled in the past century. The new data shows that a number of prior assessments of daily summer temperature change underestimated heat wave events in western Europe by approximately 30 percent.

Paul Della-Marta and a team of scientists at the University of Bern in Switzerland compiled evidence from 54 high-quality recording locations from Sweden to Croatia and report that heat waves last an average of 3 days nowwith some lasting up to 4.5 daysin comparison to an average of around 1.5 days in 1880. The results are published 3 August in the Journal of Geophysical Research-Atmospheres, a publication of the American Geophysical Union. The scientists suggest that their conclusions contribute to growing evidence that western Europe's climate has become more extreme and confirm a previously hypothesized increase in the variance of daily summer temperatures since the 19th century.

The study adds evidence that heat waves, such as the devastating 2003 event in western Europe, are a likely sign of global warming; one that perhaps began as early as the 1950s, when their study showed some of the highest trends in summer mean temperature and summer temperature variance......... Posted by: Tyler      Read more         Source