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October 9, 2006, 9:19 PM CT

Disks Around Stars

Disks Around Stars
The NASA/ESA Hubble Space Telescope, in collaboration with ground-based observatories, has at last confirmed what philosopher Emmanuel Kant and scientists have long predicted: that planets form from debris disks around stars.

More than 200 years ago, the philosopher Emmanuel Kant first proposed that planets are born from disks of dust and gas that swirl around their home stars. Though astronomers have detected more than 200 extrasolar planets and have seen many debris disks around young stars, they have yet to observe a planet and a debris disk around the same star. Now, the NASA/ESA Hubble Space Telescope, in collaboration with ground-based observatories, has at last confirmed what Kant and scientists have long predicted: that planets form from debris disks around stars.

The Hubble observations by an international team of astronomers led by G. Fritz Benedict and Barbara E. McArthur of the University of Texas, Austin, USA, show for the first time that a planet is aligned with its star's circumstellar disk of dust and gas. The planet, detected in year 2000, orbits the nearby Sun-like star Epsilon Eridani, located 10.5 light-years from Earth in the constellation Eridanus. The planet's orbit is inclined 30 degrees to Earth, the same angle at which the star's disk is tilted. The results will appear in the recent issue of the Astronomical Journal.........

Posted by: Edwin      Permalink         Source


October 9, 2006, 9:04 PM CT

Hot Nanocrystals

Hot Nanocrystals
Researchers at the Department of Energy's Lawrence Berkeley National Laboratory have discovered that nanocrystals of germanium embedded in silica glass don't melt until the temperature rises almost 200 degrees Kelvin above the melting temperature of germanium in bulk. What's even more surprising, these melted nanocrystals have to be cooled more than 200 K below the bulk melting point before they resolidify. Such a large and nearly symmetrical "hysteresis" - the divergence of melting and freezing temperatures above and below the bulk melting point - has never before been observed for embedded nanoparticles.

Phase transitions between solid and liquid or liquid and vapor are familiar phenomena in the everyday world, for example between solid water ice, liquid water, and water vapor, or steam. Eugene Haller of Berkeley Lab's Materials Sciences Division (MSD), who is also a professor of materials science at the University of California at Berkeley, uses an epicurean example: "When a solid piece of chocolate melts in the mouth, it releases a burst of flavors."

Haller explains that beyond broad scientific interest, the properties of germanium nanoparticles embedded in amorphous silicon dioxide matrices have promising applications. "Germanium nanocrystals in silica have the ability to accept charge and hold it stably for long periods, a property which can be used in improved computer memory systems. Moreover, germanium dioxide (germania) mixed with silicon dioxide (silica) offers particular advantages for forming optical fibers for long-distance communication."........

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October 9, 2006, 8:54 PM CT

Weaknesses In High-tech Immigration

Weaknesses In High-tech Immigration
Legislation pending before Congress "would admit foreign computing and engineering (C&E) workers in numbers much greater than historical trends or casual assumptions about future employment levels," according to a recent study from Georgetown University, commissioned by IEEE-USA.

The August report from Georgetown's Institute for the Study of International Migration concluded that the estimated number of new high-tech visas available under the "Comprehensive Immigration Reform Act of 2006" (S.2611) over the next 10 years could be 1.88 million. The Bureau of Labor Statistics estimates the number of new C&E workers needed by our economy over the decade is 1.25 million.

Thus, Congress was considering authorizing enough high-skill visas to fill every C&E job created in the United States over the next decade and still have 630,000 visas left over.

"The report calls into question Congress' approach to high-skill immigration reform," IEEE-USA President Ralph W. Wyndrum Jr. said. "Its analysis provides needed context to the immigration numbers being discussed on Capitol Hill".........

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October 9, 2006, 8:42 PM CT

Keeping Oil, Gas Control Systems Safe

Keeping Oil, Gas Control Systems Safe
For the past 12 months, Sandia National Laboratories has served as the lead national lab in Project LOGIIC (Linking the Oil and Gas Industry to Improve Cyber Security). The project was created to keep U.S. oil and gas control systems safe and secure, and to help minimize the chance that a cyber attack could severely damage or cripple AmericaTMs oil and gas infrastructure.

Such an attack by viruses, worms or other forms of cyber-terrorism on oil and gas industry process control networks and related systems could destabilize energy industry supply capabilities and negatively impact the national economy.

LOGIIC, funded by the Department of Homeland Security's Science and Technology Directorate, brought together 14 organizations to identify ways to reduce cyber vulnerabilities in process control and SCADA (Supervisory Control And Data Acquisition) systems. The goal of the project was to identify new types of security sensors for process control networks.

Sandia worked with project partners to create a simulation test bed and apply this environment to counter potential threats to the oil and gas industry using hypothetical attack scenarios. Sandia researchers created two real-time models of control systems used for refinery and pipeline operations.........

Posted by: John      Permalink         Source


October 8, 2006, 6:43 PM CT

Detailed view of Victoria Crater

Detailed view of Victoria Crater
With stunningly powerful vision, the HiRISE camera on NASA's Mars Reconnaissance Orbiter has taken a remarkable picture that shows the exploration rover Opportunity poised on the rim of Victoria crater on Mars.

The High Resolution Imaging Science Experiment (HiRISE) camera detailed the entire 800-meter (roughly half-mile) Victoria crater and the rover -- down to its rover tracks and shadows -- in a single high-resolution image taken Wednesday (Oct. 3).

Alfred S. McEwen of the University of Arizona Lunar and Planetary Laboratory released portions of the image that show views of the rover and crater at a NASA press conference in Washington, D.C., today. McEwen is principal investigator for HiRISE, which is operated from UA's Lunar and Planetary Laboratory in Tucson.

"We're poised to have a fantastic mission, and we're not even at prime science mission yet," McEwen said at NASA press briefing this morning. "This was our very first attempt to image 'off-nadir' (at an angle as opposed to straight down), and it worked fabulously well," McEwen added. "It's been an exciting week".

The HiRISE images for Victoria crater are available online at http://hiroc.lpl.arizona.edu/images/TRA/TRA_000873_1780/........

Posted by: Edwin      Permalink         Source


October 8, 2006, 6:37 PM CT

Whiskers Sense Three-dimensional World

Whiskers Sense Three-dimensional World
Many mammals use their whiskers to explore their environment and to construct a three-dimensional image of their world. Rodents, for example, use their whiskers to determine the size, shape and texture of objects, and seals use their whiskers to track the fluid wakes of their prey.

Two Northwestern University engineers have been studying the whisker system of rats to better understand how mechanical information from the whiskers gets transmitted to the brain and to develop artificial whisker arrays for engineering applications.

Mitra J. Hartmann, assistant professor of biomedical engineering and mechanical engineering in the McCormick School of Engineering and Applied Science, and Joseph H. Solomon, one of Hartmann's graduate students, have now developed arrays of robotic whiskers that sense in two dimensions, mimicking the capabilities of mammalian whiskers. They demonstrate that the arrays can sense information about both object shape and fluid flow.

A paper about the arrays, which may find application on assembly lines, in pipelines or on land-based autonomous rovers or underwater vehicles, was published in the Oct. 5 issue of the journal Nature.

"We show that the bending moment, or torque, at the whisker base can be used to generate three-dimensional spatial representations of the environment," said Hartmann. "We used this principle to make arrays of robotic whiskers that in many respects closely replicate rat whiskers." The technology, she said, could be used to extract the three-dimensional features of almost any solid object.........

Posted by: Nora      Permalink         Source


October 8, 2006, 5:11 PM CT

More Than Meets The Eye

More Than Meets The Eye
Ever watch a jittery video made with a hand-held camera that made you almost ill? With our eyes constantly darting back and forth and our body hardly ever holding still, that is exactly what our brain is faced with. Yet despite the shaky video stream, we usually perceive our environment as perfectly stable.

Not only does the brain find a way to compensate for our constantly flickering gaze, but researchers at the Salk Institute for Biological Studies have found that it actually turns the tables and relies on eye movements to recognize partially hidden or moving objects. Their findings will be published in a forthcoming issue of Nature Neuroscience.

"You might expect that if you move your eyes, your perception of objects might get degraded," explains senior author Richard Krauzlis, Ph.D., an associate professor in the Systems Neurobiology Laboratory at the Salk Institute. "The striking thing is that moving your eyes can actually help resolve ambiguous visual inputs".

Our eyes move all the time, whether to follow a moving object or to scan our surroundings. On average, our eyes move several times a second in fact, in a lifetime, our eyes move more often than our heart beats. "Nevertheless, you don't have the sense that the world has just swept across or rotated around you. You sense that the world is stable," says Krauzlis.........

Posted by: Nora      Permalink         Source


October 6, 2006, 4:53 AM CT

Black Hole Musical: Epic But Off-Key

Black Hole Musical: Epic But Off-Key Low Energy X-ray Images of M87
A gigantic sonic boom generated by a supermassive black hole has been found with NASA's Chandra X-ray Observatory, along with evidence for a cacophony of deep sound.

This discovery was made by using data from the longest X-ray observation ever of M87, a nearby giant elliptical galaxy. M87 is centrally located in the Virgo cluster of galaxies and is known to harbor one of the Universe's most massive black holes.

Scientists detected loops and rings in the hot, X-ray emitting gas that permeates the cluster and surrounds the galaxy. These loops provide evidence for periodic eruptions that occurred near the supermassive black hole, and that generate changes in pressure, or pressure waves, in the cluster gas that manifested themselves as sound.

"We can tell that many deep and different sounds have been rumbling through this cluster for most of the lifetime of the Universe," said William Forman of the Harvard-Smithsonian Center for Astrophysics (CfA).

The outbursts in M87, which happen every few million years, prevent the huge reservoir of gas in the cluster from cooling and forming many new stars. Without these outbursts and resultant heating, M87 would not be the elliptical galaxy it is today.

"If this black hole wasn't making all of this noise, M87 could have been a completely different type of galaxy," said team member Paul Nulsen, also of the CfA, "possibly a huge spiral galaxy about 30 times brighter than the Milky Way".........

Posted by: Edwin      Permalink         Source


October 5, 2006, 10:10 PM CT

Clinical Applications For New DESI Technology

Clinical Applications For New DESI Technology
Purdue University scientists have created the first two-dimensional images of biological samples using a new mass spectrometry technique that furthers the technology's potential applications for the detection of diseases such as cancer.

The technology, desorption electrospray ionization, or DESI, measures characteristic chemical markers that distinguish diseased from non-diseased regions of tissue samples within a few seconds and has eliminated the need for samples to be treated with chemicals and specially contained.

This tool has a wide range of applications and could be used in the future to address a number of medical issues, said Graham Cooks, Purdue's Henry B. Hass Distinguished Professor of Analytical Chemistry in whose lab DESI was developed.

"This technology could be used to aid surgeons in precisely and completely removing malignant tissue," he said. "With these images, we can see the exact location of tumor masses and can detect malignant sites that are indistinguishable to the naked eye".

Current surgical methods rely on the trained eye of a pathologist who views stained tissue slices under a microscope to assess what tissue must be removed.

This study was the first to take the graphical data presented by DESI mass spectrometry and turn it into a two-dimensional image of the tissue, said Demian Ifa, a member of Cooks' research team.........

Posted by: John      Permalink         Source


October 5, 2006, 10:05 PM CT

Experiment Yields Bubbly Surprise

Experiment Yields Bubbly Surprise Asymmetrical pinch-off of a burst of air from a slot-shaped nozzle.
Credit: Nathan Keim, University of Chicago
University of Chicago physicists have discovered a new class of behavior in air bubbles rising from an underwater nozzle. In this surprising behavior, the bubbles tear apart in sharp jerks instead of pinching off at a point, the research team will report in the Oct. 6 issue of the journal Physical Review Letters.

The research is helping researchers understand the mathematical explosions they encounter in the equations that govern the physics of fluids. "These are the equations of our lives," said Wendy Zhang, Assistant Professor in Physics at the University of Chicago. They govern everything from the bubbles of carbonated beverages to the venting of gas from deep oceanic fissures. They even apply to such large-scale processes such as exploding stars.

"One of the things that's nice about this field of research is that it's around you all the time," said Sidney Nagel, the Stein-Freiler Distinguished Service Professor in Physics at the University of Chicago. "It's on your tabletop and you've seen it who knows how a number of times. But by studying this so incredibly carefully, you get insights about things that happen on the celestial scale".

Chicago graduate student Nathan Keim and his co-authors-Zhang, Nagel, and Peder Moller, now a Ph.D. student at Ecole Normale Suprieure-documented their discovery using high-speed digital photography. Keim's experiment built on prior work that Zhang, Nagel and others published in Science in 2003. Until then, researchers believed that all fluids broke apart in much the same way. They believed that the cross-section of the pinching neck of any drop or bubble would become circular until it broke, regardless of its initial conditions.........

Posted by: John      Permalink         Source


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