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January 30, 2007, 6:43 PM CT

Hydrogen-Powered Lawnmowers?

Hydrogen-Powered Lawnmowers? Princeton student Claire Woo, a recipient of the NSF Research Experiences for Undergraduates award, at work in the laboratory of Jay Benziger.
Credit: Princeton University
In a breakthrough that could make fuel cells practical for such small machines as lawnmowers and chainsaws, scientists have developed a new mechanism to efficiently control hydrogen fuel cell power.

A number of standard fuel cell designs use electronics to control power output, but such designs require complex systems to manage humidity and fuel recovery and recycling systems to achieve acceptable efficiency.

The new process controls the hydrogen feed to match the mandatory power output, just as one controls the feed of gasoline into an internal combustion engine. The system functions as a closed system that uses the waste water to regulate the size of the reaction chamber, the site where the gasses combine to form water, heat and electricity.

National Science Foundation (NSF) awardee Jay Benziger of Princeton University developed the new technique with his student Claire Woo, a recipient of an NSF Research Experiences for Undergraduates award and now a doctoral candidate at the University of California, Berkeley. Woo and Benziger published their findings in the February 2007 Chemical Engineering Science, now available online.

The scientists believe the first applications for their technology will be in smaller engines. Fuel cells are currently inefficient on such scales due to the need for fuel recycling and excess hydrogen in standard designs. The researchers' new design is closed, so 100 percent of the fuel is used and there is no need for a costly fuel recycling system.........

Posted by: John      Read more         Source


January 30, 2007, 6:28 PM CT

Developing Ultrathin Digital Camera

Developing Ultrathin Digital Camera
Engineers at UC San Diego have built a powerful yet ultrathin digital camera by folding up the telephoto lens. This technology may yield lightweight, ultrathin, high resolution miniature cameras for unmanned surveillance aircraft, cell phones and infrared night vision applications.

"Our imager is about seven times more powerful than a conventional lens of the same depth," said Eric Tremblay, the first author on an Applied Optics paper published February 1, 2007, and an electrical and computer engineering Ph.D. candidate at UCSD's Jacobs School of Engineering. Eric is working with Joseph Ford, a professor of electrical and computer engineering at the Jacobs School who leads the camera project within UCSD's Photonic Systems Integration Lab. Ford is also affiliated with the UCSD division of the California Institute of Telecommunications and Information Technology, Calit2.

"This type of miniature camera is very promising for applications where you want high resolution images and a short exposure time. This describes what cell phone cameras want to be when they grow up," said Ford. "Today's cell phone cameras are pretty good for wide angle shots, but because space constraints require short focal length lenses, when you zoom them in, they're terrible. They're blurry, dark, and low contrast".........

Posted by: John      Read more         Source


January 30, 2007, 4:44 AM CT

Hot Stuff On Saturn

Hot Stuff On Saturn
UCL researchers have reported findings in the journal 'Nature' that rule out a long-held theory about why the Gas Giants like Saturn have such hot outer atmospheres.

Along with colleagues from Boston University, the team from UCL Physics & Astronomy found that the upper atmospheres of the giant planets in our solar system do not heat up in the same way as here on Earth.

A simple calculation to give the expected temperature of a planet's upper atmosphere balances the amount of sunlight absorbed by the energy lost to the lower atmosphere. However, the calculated values don't tally with the actual observations of the gas giants - they are consistently much hotter.It has long been thought that the culprit behind the heating process was the ionosphere, being driven by the planet's magnetic field, or magnetosphere. On the Earth this is seen in the auroral region where the spectacular Aurora Borealis, or Northen Lights, show where this energy transfer is taking place.

By analogy, it was believed the heating effect on the gas giants would be similar. The 'auroral zone' heating would then somehow be distributed to lower latitudes, though this is difficult to do because the high spin rates of these planets tends to prevent north-south movement.

The UCL team was investigating this redistribution when they reached their surprising conclusion. By using numerical models of Saturn's atmosphere, the researchers found that there, the net effects of the winds driven by polar energy inputs is not to heat the atmosphere, but to actually cool it equatorward of the heated region.........

Posted by: Edwin      Read more         Source


January 25, 2007, 9:32 PM CT

A Hybrid Species Of Butterfly

A Hybrid Species Of Butterfly Research professor Matthew Forister sits in front of a display of swallowtail butterflys. (Photo by: Jean Dixon)
University of Nevada, Reno researcher Matthew Forister is among a group of scientists that have documented an unusual type of speciation in the Sierra Nevada, including a hybrid species of butterfly that can trace its lineage as far back as almost a half a million years ago. In a recently published article in the leading research journal Science, the discovery is one of the most convincing cases of this type of species formation that has ever been demonstrated in animals.

"Our genetic work is what really clinched the hybrid angle," said Forister, a research professor in the College of Agriculture, Biotechnology and Natural Resources' Department of Natural Resources and Environmental Science. Forister explained that it has been known that two types of butterflies -- Lycaeides melissa and Lycaeides idas -- live in the Sierra, with the L. melissa living on the eastern slope of the Sierra and the L. idas living to the west. Forister's team found that a third species of Lycaeides has evolved in the upper alpine reaches of the Sierra.

The team used molecular genetics to show that the "new" species carries genes from both parental species. The scientists estimate that about 440,000 years ago the L. melissa and L. idas came into contact in the Sierra. Their offspring, cut off from the rest of their clan, eventually evolved into a unique and genetically distinct species.........

Posted by: Nora      Read more         Source


January 24, 2007, 7:48 PM CT

Fish Can Determine Their Social Rank

Fish Can Determine Their Social Rank Dominant male Astatotilapia burtoni
A male fish can size up potential rivals, and even rank them from strongest to weakest, simply by watching how they perform in territorial fights with other males, according to a new study by Stanford University scientists. The researchers say their discovery provides the first direct evidence that fish, like people, can use logical reasoning to figure out their place in the pecking order.

The study, published in the Jan. 25 edition of the journal Nature, is based on a unique experiment with cichlids (SIK-lids), small territorial fish from Africa. "In their natural habitat, male cichlids are constantly trying to ascend socially by beating each other up," said study co-author Russell D. Fernald, professor of biological sciences at Stanford. "It would be really valuable for them to know in advance who to pick a fight with".

The Nature experiment was designed by lead author Logan Grosenick, a graduate student in statistics at Stanford, and Tricia S. Clement, a former postdoctoral fellow. Their goal was to determine whether territorial fish use a type of reasoning called "transitive inference," in which known relationships serve as the basis for understanding unfamiliar ones.

"Transitive inference is essential to logical reasoning," Fernald explained. "It's something that kids generally figure out by age 4 or 5--Mary is taller than Fred, Fred is taller than Pete, therefore Mary is taller than Pete. It's been demonstrated in primates, rats and some bird species, but how and why it evolved in animals is a matter of debate".........

Posted by: Nora      Read more         Source


January 24, 2007, 6:24 PM CT

Novel Computed Imaging Technique

Novel Computed Imaging Technique Photo courtesy of Beckman Institute
Researchers at the University of Illinois at Urbana-Champaign have developed a novel computational image-forming technique for optical microscopy that can produce crisp, three-dimensional images from blurry, out-of-focus data.

Called Interferometric Synthetic Aperture Microscopy, ISAM can do for optical microscopy what magnetic resonance imaging did for nuclear magnetic resonance, and what computed tomography did for X-ray imaging, the scientists say.

"ISAM can perform high-speed, micron-scale, cross-sectional imaging without the need for time-consuming processing, sectioning and staining of resected tissue," said Stephen Boppart, a professor of electrical and computer engineering, of bioengineering, and of medicine at the U. of I., and corresponding author of a paper accepted for publication in the journal Nature Physics, and posted on its Web site.

Developed by postdoctoral research associate and lead author Tyler Ralston, research scientist Daniel Marks, electrical and computer engineering professor P. Scott Carney, and Boppart, the imaging technique utilizes a broad-spectrum light source and a spectral interferometer to obtain high-resolution, reconstructed images from the optical signals based on an understanding of the physics of light-scattering within the sample.........

Posted by: John      Read more         Source


January 24, 2007, 5:54 PM CT

The Sun May Have A Dimmer Switch

The Sun May Have A Dimmer Switch
THERE'S a dimmer switch inside the sun that causes its brightness to rise and fall on timescales of around 100,000 years - exactly the same period as between ice ages on Earth. So says a physicist who has created a computer model of our star's core.

Robert Ehrlich of George Mason University in Fairfax, Virginia, modelled the effect of temperature fluctuations in the sun's interior. According to the standard view, the temperature of the sun's core is held constant by the opposing pressures of gravity and nuclear fusion. However, Ehrlich believed that slight variations should be possible.

He took as his starting point the work of Attila Grandpierre of the Konkoly Observatory of the Hungarian Academy of Sciences. In 2005, Grandpierre and a collaborator, Gábor Ágoston, calculated that magnetic fields in the sun's core could produce small instabilities in the solar plasma. These instabilities would induce localised oscillations in temperature.

Ehrlich's model shows that whilst most of these oscillations cancel each other out, some reinforce one another and become long-lived temperature variations. The favoured frequencies allow the sun's core temperature to oscillate around its average temperature of 13.6 million kelvin in cycles lasting either 100,000 or 41,000 years. Ehrlich says that random interactions within the sun's magnetic field could flip the fluctuations from one cycle length to the other.........

Posted by: Edwin      Read more         Source


January 15, 2007, 9:39 PM CT

Putting A Face On The Earliest Modern Europeans

Putting A Face On The Earliest Modern Europeans This fossil specimen is the earliest largely complete example of an early modern human skull known from Europe.
Credit: Erik Trinkaus
The earliest modern humans in Europe were not completely "modern" and continued to evolve after they settled on the continent nearly 40,000 years ago, as per new research published this week in the Proceedings of the National Academy of Sciences (PNAS).

An international team of researchers, including Helene Rougier, Ph.D., post-doctoral fellow, and Erik Trinkaus, Ph.D., professor of anthropology, at Washington University in St. Louis, has been studying a 35,000-year-old cranium discovered in the Pestera cu Oase, in western Romania. The fossil specimen is the earliest largely complete example of an early modern human skull known from Europe.

The modern humans emerged within eastern Africa some 150,000 years ago, spread temporarily into extreme southwest Asia and into southern Africa, and then through northern Africa into Europe around 40,000 years ago. This skull is from the first 5,000 years of the apparent occupation of Europe by modern humans.

The cranium has no expressly Neandertal traits, those of its immediate predecessors in Europe. Yet, its combination of modern and archaic features can be used to reinforce arguments for some degree of mixture of Neandertals and modern humans, inferences that have been made from other early modern European fossils. In addition to its large face and retreating forehead, it has the largest cheek teeth so far known for an otherwise anatomically modern human.........

Posted by: Nora      Read more         Source


January 15, 2007, 9:28 PM CT

Molecular Differences Between Rice And Its Mimic

Molecular Differences Between Rice And Its Mimic
Red rice sounds like a New Orleans dish or a San Francisco treat. But it's a weed, the biggest nuisance to American rice growers, who are the fourth largest exporters of rice in the world. And rice farmers hate the pest, which, if harvested along with domesticated rice, reduces marketability and contaminates seed stocks.

Complicating matters is the fact that red rice and cultivated rice are exactly the same species, so an herbicide cannot be developed that seeks out only red rice. It would kill cultivated rice, too.

But now a plant evolutionary biologist at Washington University in St. Louis has been funded by the National Science Foundation (NSF) at $1.12 million for two years to perform genetic studies on red rice to understand molecular differences between the two that someday could provide the basis for a plan to eradicate the weed. The particular NSF program funding the research is the Plant Genome Comparative Sequencing Program.

Kenneth M. Olsen, Ph.D., Washington University assistant professor of biology in Arts & Sciences, believes that gene flow is one factor that has been at work.

"We are looking for candidate genes that underlie particular traits that differ between the two," said Olsen. "Knowing more about the traits could help in potentially controlling the weed. We have a key advantage in this research in that we know the complete cultivated rice genome, so it's fairly easy to target genes of interest".........

Posted by: Nora      Read more         Source


January 15, 2007, 7:15 PM CT

The Eagle Nebula In Infrared

The Eagle Nebula In Infrared Credit: NASA/JPL-Caltech/N. Flagey (IAS/SSC) & A. Noriega-Crespo (SSC/Caltech)
In visible light, the whole thing looks like an eagle. The region was captured recently in unprecedented detail in infrared light by the robotic orbiting Spitzer Space Telescope (SSC). Shown above, the infrared image allows observers to peer through normally opaque dust and so better capture the full complexity of the Eagle Nebula star forming region.

In particular, the three famous pillars near the image center are seen bathed in dust likely warmed by a supernova explosion. The warm dust is digitally assigned the false color of red. Also visible, near the bottom of the image, is ten light-year long pillar sometimes dubbed the Fairy of Eagle Nebula. The greater Eagle emission nebula, tagged M16, lies about 6500 light years away, spans about 20 light-years, and is visible with binoculars toward the constellation of Serpens.........

Posted by: Edwin      Read more


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