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April 9, 2006, 8:16 PM CT

Cosmic Spider is Good Mother

Hanging above the Large Magellanic Cloud (LMC) - one of our closest galaxies - in what some describe as a frightening sight, the Tarantula nebula is worth looking at in detail. Also designated 30 Doradus or NGC 2070, the nebula owes its name to the arrangement of its brightest patches of nebulosity that somewhat resemble the legs of a spider. This name, of the biggest spiders on Earth, is also very fitting in view of the gigantic proportions of the celestial nebula - it measures nearly 1,000 light years across!.

The Tarantula nebula is the largest emission nebula in the sky and also one of the largest known star-forming regions in all the Milky Way's neighbouring galaxies. Located about 170,000 light-years away, in the southern constellation Dorado (The Swordfish), it can be seen with the unaided eye.

As shown in this image obtained with the FORS1 multi-mode instrument on Eso's Very Large Telescope, its structure is fascinatingly complex, with a large number of bright arcs and apparently dark areas in between. Inside the giant emission nebula lies a cluster of young, massive and hot stars, denoted R 136, whose intense radiation and strong winds make the nebula glow, shaping it into the form of a giant arachnid. The cluster is about 2 to 3 million years old, that is, almost from 'yesterday' in the 13.7 billion year history of the Universe.........

Posted by: Edwin      Permalink         Source


April 6, 2006, 11:25 PM CT

"A" ring contains more debris

Views of Saturn's stunning ring system from above by the Cassini-Huygens spacecraft now orbiting the planet indicate the prominent A ring contains more debris than once thought, according to a new University of Colorado at Boulder study.

Previous observations with the Voyager spacecraft in the early 1980s found the ring was more transparent, indicating less material, said Joshua Colwell of CU-Boulder's Laboratory for Atmospheric and Space Physics. But new calculations based on May 2005 observations with Cassini's Ultraviolet Imaging Spectrograph, or UVIS, indicates the opacity of the ring is up to 35 percent higher than previously reported.

Because of the uneven distribution of the ring particles - which range in size from dust grains to school buses - the transparency of the rings depends on the angle from which they are viewed, he said. The particles are arranged essentially parallel in long stringy clumps as large as 60 feet across, 16 feet thick and 160 feet long, according to models produced from observation data, said Colwell.

A paper on the subject by Colwell, Larry Esposito and Miodrag Sremcevic of CU-Boulder's LASP appears in the April 1 issue of Geophysical Research Letters, or GRL. Esposito is science team leader for UVIS, a $12.5 million instrument designed and built at CU-Boulder by LASP that is riding on the Cassini spacecraft.........

Posted by: Edwin      Permalink         Source


April 6, 2006, 11:10 PM CT

Nanopore To Revolutionize Genome Sequencing

Nanopore To Revolutionize Genome Sequencing

A team led by physicists at the University of California, San Diego has shown the feasibility of a fast, inexpensive technique to sequence DNA as it passes through tiny pores. The advance brings personalized, genome-based medicine closer to reality.

The paper, published in the recent issue of the journal Nano Letters, describes a method to sequence a human genome in a matter of hours at a potentially low cost, by measuring the electrical perturbations generated by a single strand of DNA as it passes through a pore more than a thousand times smaller than the diameter of a human hair. Because sequencing a person's genome would take several months and millions of dollars with current DNA sequencing technology, the researchers say that the new method has the potential to usher in a revolution in medicine.

"Current DNA sequencing methods are too slow and expensive for it to be realistic to sequence people's genomes to tailor medical treatments for each individual," said Massimiliano Di Ventra, an associate professor of physics at UCSD who directed the project. "The practical implementation of our approach could make the dream of personalizing medicine according to a person's unique genetic makeup a reality".

The physicists used mathematical calculations and computer modeling of the motions and electrical fluctuations of DNA molecules to determine how to distinguish each of the four different bases (A, G, C, T) that constitute a strand of DNA. They based their calculations on a pore about a nanometer in diameter made from silicon nitride-a material that is easy to work with and commonly used in nanostructures-surrounded by two pairs of tiny gold electrodes. The electrodes would record the electrical current perpendicular to the DNA strand as the DNA passed through the pore. Because each DNA base is structurally and chemically different, each base creates its own distinct electronic signature.........

Posted by: John      Permalink         Source


April 6, 2006, 10:48 PM CT

Wireless Sensor Networks Gives Assurance

Wireless Sensor Networks Gives Assurance Broken gas line, Balboa Boulevard, Los Angeles, California, 1994 Northridge earthquake (photograph by M. Rymer)
An earthquake strikes a large city, wrecking roads and bridges, stranding rush-hour commuters, trapping office workers inside high-rise buildings.

As director of the city's transportation authority, you have minutes to make a momentous decision. What is the safest, fastest route that rescue teams can take to travel to hard-hit areas of the city? Which bridges, even if damaged, can still support traffic loads?

Questions like these are increasingly on the minds of structural engineers and emergency personnel as the world prepares to mark the 100th anniversary of the Great San Francisco Earthquake of April 18, 1906.

The answers to the questions, says Yunfeng Zhang, can be provided by sensors - networks of tiny sensors with built-in computer chips that are attached to a bridge to monitor its safety and performance.

Sensors deployed strategically on a bridge, says Zhang, an assistant professor of civil and environmental engineering at Lehigh University, can provide a high-resolution, multi-dimensional picture of the health of a structure, giving engineers vital information about a bridge's performance and, in the aftermath of a catastrophe, its ability to carry traffic.

To be useful in the event of an earthquake or other emergency, says Zhang, sensor data must be transmitted in real time, virtually without delay, to remote processing centers for interpretation and then to decision-makers.........

Posted by: John      Permalink         Source


April 6, 2006, 10:25 PM CT

Blue Ring Around The Planet Uranus

Blue Ring Around The Planet Uranus
The outermost ring of the planet Uranus turns out to have a bright blue color, as per a report in the April 7 issue of the journal Science. That makes it only the second blue ring to be found in the solar system. The first circles the planet Saturn.

Perhaps not coincidentally, both blue rings are associated with small moons. Astronomers suspect the rings owe their blue color to subtle forces acting on dust in the rings that allow smaller particles to survive while larger ones are recaptured by a moon.

"The outer ring of Saturn is blue and has [the moon] Enceledus right smack at its brightest spot, and Uranus is strikingly similar, with its blue ring right on top of [the moon] Mab's orbit," says Imke de Pater, who is an astronomer at the University of California, Berkeley, and a co-author of the Science paper. "The blue color says that this ring is predominantly submicron-sized material, much smaller than the material in most other rings, which appear red."

De Pater and her co-authors believe the similarity between the outer rings implies an in kind explanation for their blue color. A number of other researchers have ascribed Saturn's blue ring to the small dust, gas and ice particles spewed into Encedadus' orbit by newly discovered plumes on that moon's surface. But that is unlikely to be the case with Mab, a small, dead, rocky ball, about 15 miles across-one-twentieth the diameter of Enceladus.........

Posted by: Edwin      Permalink         Source


April 6, 2006, 10:19 PM CT

Vulnerabilities of Rapidly Growing Internet Phone

Vulnerabilities of Rapidly Growing Internet Phone
The National Science Foundation (NSF) has issued four awards totaling $600,000 to the University of North Texas (UNT) to lead a multi-university collaboration to develop a geographically distributed, secure test bed to analyze vulnerabilities in Voice over Internet Protocol (VoIP)--an increasingly popular technology that turns audio signals into digital data that can be transmitted over the Internet.

The three-year project will investigate voice spam prevention (VoIP phone systems can be spammed like email), attacks on networks and Internet resources that render them unavailable (denial of service), quality of service, and 911 service dependability. The unique test bed will also be used to discover security holes arising from operating VoIP with conventional phone networks.

"Proactively securing the next-generation infrastructure for voice communications is critical for us all," said UNT's Ram Dantu, who leads the project. "Our research will identify vulnerabilities in the technology and establish solutions--before damage is done".

VoIP allows users with a computer and a standard Internet connection to make toll-free calls anywhere in the world. It also handles video and instant messaging. Companies such as Vonage and AT&T are aggressively deploying the technology, and one study predicts some 24 million U.S. households will be using VoIP by 2008. Government agencies are already implementing strategies to use VoIP-based systems.........

Posted by: John      Permalink         Source


April 5, 2006, 11:21 PM CT

Monitoring Plant Health

Monitoring Plant Health
Green fingered amateur gardeners often talk to their plants; now the plants can talk back. Researchers have developed a system that picks up the subtle cues of plant communication helping plant growers to monitor the crop's state of health and will result in optimal environmentally-friendly growing conditions.

Funded under the European Commission's FET (Future and Emerging Technologies) initiative of the IST programme, the PLANTS project sought to develop a unique system that linked plants, technology and people to continuously assess the state of crop health. Using sensors, transmitters and specialist software, the system monitors the state of the crop on a plant-by-plant basis, in near real-time.

Dr Anthony Morrissey at Tyndall National Institute (Ireland) led the project which included partners from University College Cork (Ireland), Computer Technology Institute (CTI, Greece) and Eden Project Ltd (UK).

"You could almost walk away from the crop and let it grow on its own," says Dr Fiona Tooke of the Eden Project, a unique public education facility in the UK's Cornwall region that gathers all the planet's major agricultural systems under a series of spectacular, and immense, plastic domes that function as high tech glasshouses. Eden joined the PLANTS project to help promote, and disseminate the ideas and philosophy behind the project.........

Posted by: John      Permalink         Source


April 4, 2006, 11:55 PM CT

Ocean Dust Busters

Ocean Dust Busters
Like most living things, microscopic marine plants need iron and other minerals to live and grow. On land, soil provides a ubiquitous source of minerals, but how do essential nutrients get into vast watery stretches of the open ocean?

The question has long mystified oceanographers. As per one theory, large swirling currents, called eddies, pump nutrients from the depths up toward the sunlit surface, giving phytoplankton the ingredients they need to flourish. But a larger source of iron may be dust storms, which blow huge quantities of mineral-rich soil particles (called Aeolian dust) out to sea, especially from desert regions in Africa and Asia.

Until now, researchers investigating the latter theory have been stymied by an inability to measure when, where, and how much dust falls into the oceans, said Ed Sholkovitz, a marine geochemist at Woods Hole Oceanographic Institution (WHOI). They have had to rely on dust samples collected on islands.

To remedy this situation, Sholkovitz teamed with three WHOI engineers-Geoff Allsup, David Hosom, and Mike Purcell-who collectively call themselves the Dust Busters. They designed a device, mounted atop a moored buoy, that collects wind-blown particles in the open ocean. Unlike islands, which aren t portable, buoys can be placed in scientifically strategic locales.........

Posted by: Edwin      Permalink         Source


April 4, 2006, 11:52 PM CT

The 250,000 Ton Punch

The 250,000 Ton Punch
Over the weekend of 9-10 July 2005 a team of UK and US scientists, led by Dr. Dick Willingale of the University of Leicester, used NASAE28099s Swift satellite to observe the collision of NASA's Deep Impact spacecraft with comet Tempel 1.

Reporting today (Tuesday) at the UK 2006 National Astronomy Meeting in Leicester, Dr. Willingale revealed that the Swift observations show that the comet grew brighter and brighter in X-ray light after the impact, with the X-ray outburst lasting a total of 12 days.

"The Swift observations reveal that far more water was liberated and over a longer period than previously claimed," said Dick Willingale.

Swift spends most of its time studying objects in the distant Universe, but its agility allows it to observe a number of objects per orbit. Dr. Willingale used Swift to monitor the X-ray emission from comet Tempel 1 before and after the collision with the Deep Impact probe.

The X-rays provide a direct measurement of how much material was kicked up after the impact. This is because the X-rays were created by the newly liberated water as it was lifted into the comet's thin atmosphere and illuminated by the high-energy solar wind from the Sun.

"The more material liberated, the more X-rays are produced," explained Dr. Paul O'Brien, also from the University of Leicester.........

Posted by: Edwin      Permalink         Source


April 4, 2006, 0:13 AM CT

Confirming Neutrino Oscillation

Confirming Neutrino Oscillation The NuMI beam line is the business end of Fermilab's neutrino "gun."
Credit: Peter Ginter, Fermilab
By sending a high-intensity beam of subatomic particles known as neutrinos from a laboratory in Batavia, Ill., to a particle detector located deep in a mine in Soudan, Minn., researchers have confirmed the neutrinos really do "oscillate," changing from one kind to another as they fly along.

The payoff could be a deeper understanding of the ghostly neutrino particles, which can traverse the entire Earth without interacting with matter. Ultimately, in fact, these elusive particles may help us understand the origins of the neutrons, protons and electrons that make up all the matter in the world around us.

Such oscillations have been observed in earlier experiments. But new experiments from the Main Injector Neutrino Oscillation Search (MINOS) based at the Fermi National Accelerator Laboratory will eventually examine the effect in much greater detail, and under controlled conditions.

"Using a man-made beam of neutrinos, MINOS is a great tool to study the properties of neutrinos in a laboratory-controlled environment," said Stanford University professor Stan Wojcicki, spokesperson for the experiment.

Their first result corroborates earlier observations of muon neutrino disappearance, made by the Japanese Super-Kamiokande and K2K experiments.........

Posted by: John      Permalink         Source


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