September 17, 2007, 5:07 AM CT

The Origin Of Soil-scented Geosmin

Brown University chemists have found the origins of an odor - the sweet smell of fresh dirt. In Nature Chemical Biology, the Brown team shows that the protein that makes geosmin - source of the good earth scent - has two similar but distinct halves, each playing a critical role in making this organic compound.

"Everyone is familiar with the wonderful smell of warm earth," said David Cane, professor of chemistry at Brown who oversaw the research. "Now we know precisely how it is made".

Geosmin, which literally translates to "earth smell," was scientifically identified more than 100 years ago. In soil, bacteria produce the chemical compound. In water, blue-green algae make it. Along with the pleasant scent of warm, moist soil, geosmin is also responsible for the muddy "off" taste in some drinking water. That is why the substance is of interest to water purification experts and even vintners, who want to keep the non-malignant but pungent substance out of their wine.

Until recently, researchers knew little about how geosmin is made. Then, a few years ago, Cane found the gene responsible for geosmin formation in Streptomyces coelicolor, a strain of plant-munching bacteria found in soil. Last year, the team discovered that a single protein converts farnesyl diphosphate to geosmin......... Posted by: Sarah      Read more         Source

September 12, 2007, 8:31 PM CT

Emissions targets for 2030 will only be reached by banning cars in London

London Authority (GLA) takes radical steps, one of which could be the removal of all cars from both inner and outer London, as per a report published recently.

The GLA is committed to reducing Londons carbon dioxide emissions by 60% by 20251, but most climate researchers argue that even more rapid reductions will be needed if we are to avoid dangerous climate change2. A team of experts from the London School of Hygiene & Tropical Medicine (LSHTM) and the Transport Studies Unit (Oxford University Centre for the Environment) will today reveal that London is on course to reduce land transport emissions by only 10%-23%3,4.

They do, however, offer a radical vision which could achieve a 72% drop in emissions by 2030 a figure that is 83% lower than the current UK average. The solution involves combining a car-free London with high levels of active transport (for example walking and cycling) and realistic but challenging energy-efficient improvements.

Their findings will be released recently at a press event taking place at LSHTM to launch the Lancet Series on Energy and Health, which looks at access to electricity and energy poverty, transport, agriculture, nuclear and renewable power, and a range of other energy issues, and the effect each has on health. The Series calls for action to be taken at personal, national and global level to address these issues......... Posted by: William      Read more         Source

September 12, 2007, 8:29 PM CT

Role Of Climate In Neanderthal Extinction

THE mystery of what killed the Neanderthals has moved a step closer to resolution after an international study led by the University of Leeds has ruled out one of the competing theories catastrophic climate change as the most likely cause.

The bones of more than 400 Neanderthals have been found since the first discoveries were made in the early 19th century. The finds suggest the Neanderthals, named after the Neander Valley near Dsseldorf, where they were first recognized as an extinct kind of archaic humans, inhabited Europe and parts of western Asia for more than 100,000 years.

The causes of their extinction have puzzled researchers for years with some believing it was due to competition with modern humans, while others blamed deteriorating climatic conditions. But a new study published recently in Nature has shown that the Neanderthal extinction did not coincide with any of the extreme climate events that punctuated the last glacial period.

The research was led by Professor Chronis Tzedakis, a palaeoecologist at the University of Leeds, who explained: Until now, there have been three limitations to understanding the role of climate in the Neanderthal extinction: uncertainty over the exact timing of their disappearance; uncertainties in converting radiocarbon dates to actual calendar years; and the chronological imprecision of the ancient climate record......... Posted by: William      Read more         Source

September 12, 2007, 8:26 PM CT

peanut butter program for starving children

An enriched peanut-butter mixture given at home is successfully promoting recovery in large numbers of starving children in Malawi, as per a group of scientists at Washington University School of Medicine in St. Louis.

Malnutrition affects 70 percent of all Malawian children with an estimated 13 percent of children dying from it before the age of five.

Mark J. Manary, M.D., professor of pediatrics and an emergency pediatrician at St. Louis Children's Hospital, has spent several years researching the use of the enriched peanut-butter mixture, called Ready-to-Use Therapeutic Food (RUTF) with small groups of severely and moderately malnourished young children in the sub-Saharan African country. The nutrient-rich mixture contains peanuts, powdered milk, oil, sugar, and added vitamins and minerals. Produced in a Malawian factory, the mixture is given to the mothers of the children to feed at home.

While Manary's team had promising results in using the RUTF in a small setting, it hadn't used the therapy in large-scale operations because of limited human and material resources. The team embarked on a three-year study to implement the peanut-butter feeding program using the existing health-care system in Malawi. Results of the study appeared in the recent issue of Maternal and Child Nutrition......... Posted by: Sean      Read more         Source

September 12, 2007, 8:09 PM CT

The mysterious ridges at the mouth of Tiu Valles

These images taken by the High Resolution Stereo Camera (HRSC) on board Mars Express show the mouth of the Tiu Valles channel system on the red planet.

The pictures were taken in orbit 3103 on 10 June 2006 with a ground resolution of approximately 16 metres per pixel.

The mouth of Tiu Valles is an estuary-like landform. On Earth, an estuary is the tidal mouth of a river valley, or the end that meets the sea and fresh water comes into contact with seawater. In such an area, tidal effects are evident.

Tiu Valles is located at approximately 27 degree North and 330 degree East. The sun illuminates the scene from the North West, the lower left-hand side in the image.

Tiu Valles originates in the equatorial chaotic terrains at the mouth, at the eastern end of Valles Marineris. The morphology of this chaotic terrain is dominated by large-scale remnant massifs, which are large relief masses that have been moved and weathered as a block. These are randomly oriented and heavily eroded.

From there, the region extends to the north over a distance of 1500 km before terminating in Chryse Planitia. Along with Kasei Valles and Ares Valles, Tiu Valles is one of the major outflow channels entering the Chryse Planitia plain.

The scene in the images covers an area of approximately 140 by 80 km at the mouth of Tiu Valles. The region was made famous in 1997 when rover Sojourner of NASA's Pathfinder mission landed about 600 km south-west of the mapped area......... Posted by: Brooke      Read more         Source

September 12, 2007, 6:54 PM CT

Lighter gas reduces damage to optics

Scientists at the University of Illinois have discovered a way to generate light and reduce damage in a leading candidate for next-generation microelectronics lithography. The technique could help pack more power into smaller computer chips.

In the quest for creating computer chips with ever-smaller feature sizes, chip manufacturers are exploring extreme ultraviolet lithography as the next chip-printing technology. For a light source at the necessary wavelength, researchers have turned to a hot, ionized gas called a plasma, generated within a Z-pinch device. But, energetic ions produced in the plasma can damage the mirror responsible for collecting the light.

"By adding a lighter gas to the plasma, we can significantly reduce the damage and extend the lifetime of the collector optics," said David Ruzic, a professor of nuclear, plasma and radiological engineering and lead author of a paper that describes the technique in the recent issue of the journal IEEE Transactions on Plasma Science.

In a Z-pinch device, xenon is fed into a chamber where it collides with a stream of electrons, producing a low-temperature and low-density plasma. This plasma then flows between two cylindrical electrodes, one positioned inside the other. (The "Z" in Z-pinch refers to the direction of current flow along the cylindrical electrodes.)......... Posted by: Kevin      Read more         Source

September 12, 2007, 5:48 PM CT

First Prehistoric Reptiles To Possess Modern Ears

The discovery of the first anatomically modern ear in a group of 260 million-year-old fossil reptiles significantly pushes back the date of the origin of an advanced sense of hearing, and suggests the first known adaptations to living in the dark.

In a new study published in PLoS One, Johannes Müller and Linda Tsuji, paleobiologists at the Natural History Museum of the Humboldt University in Berlin, Germany report that these fossil animals, found in deposits of Permian age near the Mezen River in central Russia, possessed all the anatomical features typical of a vertebrate with a surprisingly modern ear.

When vertebrates had conquered land and the ancestors of modern day mammals, reptiles, and birds first began to diversify, hearing was not of high importance. The first fully terrestrial land vertebrates were, in fact, largely deaf, and lacked any of the anatomical features that would indicate the possession of what is termed impedance-matching hearing - the mechanism by which modern land vertebrates are able to transmit airborne sounds into the inner ear by means of small bony connections.

The ability of modern animals to hear a wide range of frequencies, highly important for prey capture, escape, and communication, was long assumed to have only evolved shortly before the origin of dinosaurs, not much longer than 200 million years ago, and therefore comparatively late in vertebrate history......... Posted by: William      Read more         Source

September 10, 2007, 10:21 PM CT

Study reveals predation-evolution link

The fossil record seems to indicate that the diversity of marine creatures increased and decreased over hundreds of millions of years in step with predator-prey encounters, Virginia Tech geoscientists report in the Proceedings of the National Academy of Science.

For decades, there has been a debate between paleontologists, biologists, and ecologists on the role of ecological interactions, such as predation, in the long term patterns of animal evolution.

John Warren Huntley, a postdoctoral scientist in the Department of Geosciences at Virginia Tech, and Geosciences Professor Micha Kowalewski decided to look at the importance of ecology by surveying the literature for incidents of predation in marine invertebrates, such as clams and their relatives.

Today, certain predators leave easy to identify marks on the shells of their prey, such as clean, round holes, said Huntley. Such holes drilled by predators can also be found in fossil shells.

The researchers also looked for repair scars on the shells of creatures that survived an attack.

The study was conducted by looking at studies which reported the frequency of drill holes and repair scars in fossil species from the last 550 million years.

First Huntley and Kowalewski found that predation increased notably about 480 million years ago, some 50 million years earlier than previous studies have found. The earlier studies were based on changes in morphology predators with stronger claws and jaws and prey with more ornamented shells. We looked at the frequency of attacks, which increased about 50 million years before the changes in armor, said Huntley......... Posted by: William      Read more         Source

September 10, 2007, 10:04 PM CT

Tiny Tubes and Rods as Catalysts

Researchers at the U.S. Department of Energy's Brookhaven National Laboratory have developed new ways to make or modify nanorods and nanotubes of titanium oxide, a material used in a variety of industrial and medical applications. The methods and new titanium oxide materials may lead to improved catalysts for hydrogen production, more efficient solar cells, and more protective sunscreens. The research is published in two papers now available online, one in Advanced Materials (August 22, 2007), and the other in the Journal of Physical Chemistry.

A number of researchers have explored ways to improve the light-absorbing capability of titanium oxide, for example, by "doping" the material with added metals. Han and his colleagues took a new approach. They enhanced the material's light-absorption capability by simply introducing nanocavities, completely enclosed pockets measuring billionths of a meter within the 100-nanometer-diameter solid titanium oxide rods.

The resulting nanocavity-filled titanium oxide nanorods were 25 percent more efficient at absorbing certain wavelengths of ultraviolet A (UVA) and ultraviolet B (UVB) solar radiation than titanium oxide without nanocavities.

"Our research demonstrates that titanium oxide nanorods with nanocavities can dramatically improve the absorption of UVA and UVB solar radiation, and thus are ideal new materials for sunscreen," Han said......... Posted by: Sarah      Read more         Source

September 10, 2007, 9:46 PM CT

Nanoscale Features the Easy Way

Researchers at the Georgia Institute of Technology have developed a new technique for nanolithography that is extremely fast and capable of being used in a range of environments including air (outside a vacuum) and liquids. Scientists have demonstrated the technique, known as thermochemical nanolithography, as a proof of concept. The technique may allow industry to produce a variety of nanopatterned structures, including nanocircuits, at a speed and scale that could make their manufacture commercially viable. The research, which has potential applications for fields ranging from the electronics industry to nanofluidics to medicine, appeared earlier this year in the journal Nano Letters.

The technique is surprisingly simple. Using an atomic force microscope (AFM), scientists heat a silicon tip and run it over a thin polymer film. The heat from the tip induces a chemical reaction at the surface of the film. This reaction changes the film's chemical reactivity and transforms it from a hydrophobic substance to a hydrophilic one that can stick to other molecules. The technique is extremely fast and can write at speeds faster than millimeters per second. That's orders of magnitude faster than the widely used dip-pen nanolithography (DPN), which routinely clocks at a speed of 0.0001 millimeters per second......... Posted by: Kevin      Read more         Source