February 13, 2006, 10:40 PM CT

Snows Of Kilimanjaro Disappearing

Five years after warning that the famed ice fields on Tanzania 's Mount Kilimanjaro may melt, Ohio State University scientists have sadly found that their prediction is coming true.

And the impact of the loss of that ice atop Africa 's highest peak - disregarding the loss of tourism that will follow the vanishing ice - could add to the heavy drought burden already facing those living near that mountain.

For Lonnie Thompson, professor of geological sciences, his third expedition to the summit of Kilimanjaro was all too much like visiting a sick friend in failing health.

In 2002, Thompson and colleagues shocked the scientific community with their prediction that the ice fields capping the mountain would disappear between 2015 and 2020, the victims, at least in part, of global warming. Returning to his campus office last week, he admits that nothing has happened to alter that prediction.

In fact, the mountain's ice fields may disappear sooner.

"The change there is so dramatic," he said. "We can see it both in the field and from aerial photographs of the mountaintop. I would say it is on track to disappear, and the rate of ice loss may even be accelerating.

"But we need to look at the numbers to confirm that."

The "numbers" he refers to are the combined data gathered from both the most recent and earlier expeditions, and from aerial surveys of the ice fields. By comparing these with past data, they can calculate just how much of Kilimanjaro's ice has vanished. About 82 percent of the ice fields were lost between the time they were first mapped in 1912 and 2000.........

Posted by: Tyler      Permalink         Source

February 12, 2006, 11:07 PM CT

Cell Version Of DNA Chip

A new technique in which single strands of synthetic DNA are used to firmly fasten biological cells to non-biological surfaces has been developed by scientists with the Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California at Berkeley. This technique holds promise for a wide variety of applications, including biosensors, drug-screening technologies, the growing of artificial tissues and the design of neural networks.

"Just as DNA chips revolutionized genome analysis, we hope to make cell chips (self-assembled arrays of cells on a thumbnail-sized chip) using our DNA-based cell adhesion strategy," said Ravi Chandra, a researcher affiliated with Berkeley Lab's Physical Biosciences Division and UC Berkeley's Chemistry Department. "Cell chips could be used as biosensors for detecting the presence of pathogens, or for drug screening, just to name of a few of the a number of possibilities".

Chandra is the lead author of a paper that appears in the latest issue of the international chemistry journal Angewandte Chemie. The other authors are Erik Douglas, Richard Mathies, Carolyn Bertozzi and Matthew Francis. The paper is entitled: Programmable Cell Adhesion Encoded by DNA Hybridization.

A number of of the vast assortment of biological cells are naturally sticky, a property that enables individual cells to adhere to other cells and non-cellular components, which in turn enables them to assemble into different types of tissue, or carry out functions critical to an organism's health and well-being. Cell adhesion is now being used to incorporate biological cells into simple devices, but is expected to be important for the future production of complex nanotechnology devices.........

Posted by: Kevin      Permalink

February 12, 2006, 9:47 PM CT

How Do You Steal A Million Stars?

Based on observations with ESO's Very Large Telescope, a team of Italian astronomers reports that the stellar cluster Messier 12 must have lost to our Milky Way galaxy close to one million low-mass stars.

"In the solar neighbourhood and in most stellar clusters, the least massive stars are the most common, and by far", said Guido De Marchi (ESA), lead author of the study. "Our observations with ESO's VLT show this is not the case for Messier 12."

The team, which also includes Luigi Pulone and Francesco Paresce (INAF, Italy), measured the brightness and colours of more than 16,000 stars within the globular cluster Messier 12 with the FORS1 multi-mode instrument attached to one of the Unit Telescopes of ESO's VLT at Cerro Paranal (Chile). The astronomers could study stars that are 40 million times fainter than what the unaided eye can see (magnitude 25).

Located at a distance of 23,000 light years in the constellation Ophiuchus (The Serpent-holder), Messier 12 got its name by being the 12th entry in the catalogue of nebulous objects compiled in 1774 by French astronomer and comet chaser Charles Messier. It is also known to astronomers as NGC 6218 and contains about 200,000 stars, most of them having a mass between 20 and 80 percent of the mass of the Sun.........

Posted by: Brooke      Permalink     

February 12, 2006, 7:57 PM CT

Most Ambitious Star Survey Ever

An international team of astronomers today announced the first results from the Radial Velocity Experiment, an ambitious all-sky spectroscopic survey aimed at measuring the speed, temperature, surface gravity and composition of up to a million stars passing near the sun. Those first results from the project, known for short as RAVE, confirm that dark matter dominates the total mass of our home galaxy, the Milky Way, team members at The Johns Hopkins University and elsewhere said. The full survey promises to yield a new, detailed understanding of the origins of the galaxy, they said.

The results were released at the American Astronomical Society's 207th meeting in Washington, D.C.

The team is using the "six-degree field" multi-object spectrograph on the 1.2-m UK Schmidt Telescope at the Anglo-Australian Observatory, located at Siding Spring Observatory in New South Wales, Australia. The instrument is capable of obtaining spectroscopic information for as a number of as 150 stars at once, said Rosemary Wyse, a professor in the Henry A. Rowland Department of Physics and Astronomy in Johns Hopkins' Krieger School of Arts and Sciences and a member of the RAVE team.........

Posted by: Brooke      Permalink         Read more....

February 11, 2006, 3:14 PM CT

Role Of Hydrogen Bonds In Protein Folding

By changing individual atoms in key places in proteins, Duke University chemists have found new evidence for the importance of comparatively weak "hydrogen bonds" in enabling stringlike proteins to fold into the maximally stable shape they need to assume their roles as biological workhorses. Such protein folding immediately after proteins are synthesized is central to their function in the cell.

Eventhough they are much weaker than the preeminent "covalent" chemical bonds that bind atoms in biological molecules, hydrogen bonds are known to occur at key points along the central "backbone" structures of all folded proteins. The hydrogen bonds are created by attractions between adjacent hydrogen and oxygen atoms that are sandwiched into the molecular framework.

How big a role hydrogen bonds actually play in protein folding has been a controversial scientific question, as per Duke associate chemistry professor Michael Fitzgerald. "There's been an ongoing debate about the exact role of those hydrogen bonds," he said in an interview. "Are they really super-important, or are they really negligible?".

Fitzgerald, his graduate student Min Wang and his former graduate student Thomas Wales helped address that question in an effort that took years of work.

One by one, they slightly "mutated" the normal arrangement of atoms in proteins to effectively delete hydrogen bonds at five analogous positions along the structural "backbones" of two different protein molecules that fold in the same pattern. Then they analyzed how each deletion affected the stability of the protein. "Stability" means how low energy, or "relaxed," the protein was.........

Posted by: Sarah      Permalink         Source


February 11, 2006, 1:53 PM CT

Giant Magellan Telescope

You would not want to play poker with Wendy Freedman. Even her children say so, she admits, and as she sits across the table on a summer morning in Tucson, Arizona, she gives no hint that she has just pushed almost all her chips into the middle of the table.

At this moment, about six miles away, a giant orange oven rotates, spinning up to its target speed of five revolutions per minute, on its way to its programmed temperature of about 2130 degrees Fahrenheit. By then, it will hold a lake of glass, 20 tons of borosilicate.

For another three days the oven will continue to spin, driving that lake of liquid glass into a parabola 330 inches across. Over the next several months, the glass will be slowly cooled and then polished exquisitely, to within.000001 of an inch of the theoretically perfect shape. Add an aluminum coating about 400 atoms thick, and there it will be: a telescope mirror, one of the largest in the world.........

Posted by: Brooke      Permalink    Read more....


February 11, 2006, 12:39 AM CT

If Winter Olympic Games Were Held On The Moon

It's only a matter of time. One day, winter Olympics will be held on the moon. The moon's dust-covered slopes are good places to ski. There's plenty of powder, moguls and, best of all, low-gravity. With only 1/6th g holding them down, skiers and snowboarders can do tricks they only dreamed of doing on Earth. How about an octuple-twisting quadruple backflip? Don't worry. Crashes happen in slow-motion, so it won't hurt so much to wipe out.

And there's a perfect spot for the Olympic Village: the crater Plato. Most people don't know it, but Plato of ancient Greece was not only a philosopher, but also an Olympic champion. Twice he won the pankration competition-a grueling mix of boxing and wrestling. A crater named after Plato sounds like a good place for Olympic athletes to stay. The site is flat-bottomed, filled with raw materials for building stadia and habitats, and like Torino, Italy, the site of this year's games, Plato is near the Alps.

That is, the lunar Alps.

The lunar Alps are a range of mountains on the moon named after the Alps of Europe. They are similar to their Earthly counterparts in height, breath and spectacle. Since the modern Olympics began in 1896, most of the winter games have been held in the Alps. Why should the moon be different?........

Posted by: Brooke      Permalink    Read more....


February 9, 2006, 11:06 PM CT

More Compact, Inexpensive Spectrometer

Being the delicate optical instruments that they are, spectrometers are pretty picky about light.But Georgia Tech scientists have developed a technology to help spectrometers - instruments that can be used as the main parts of sensors that can detect substances present in even ultra-small concentrations - analyze substances using fewer parts in a wider variety of environments, regardless of lighting.

The technology can improve the portability while reducing the size, complexity, and cost of a number of sensing and diagnostics systems that use spectrometers. The technology has appeared in Applied Optics, Optics Express and Optics Letters and was presented as an invited talk at the IEEE Lasers and Electro-Optics Society Annual Meeting 2005.

Conventional spectrometers have multiple parts - a narrow slit, a lens (to guide light), a grating (to separate wavelengths), a second lens and a detector (to detect the power at different wavelengths). The Georgia Tech team's goal was to combine all these pieces into two parts, a volume hologram (formed in an inexpensive piece of polymer) and a detector, to create a compact, efficient and inexpensive spectrometer that could be used for multiple spectroscopy and sensing applications.

"This technology is very useful for low-end spectrometers, but at the same time, there are a number of applications that require high-end spectrometers. This technology could convert a portion of a complex, high-end system into a much more versatile and light system," said Ali Adibi, head of the project and an associate professor in the School of Electrical and Computer Engineering.........

Posted by: Kevin      Permalink


February 9, 2006, 10:48 PM CT

Improving Distance Measurement

Researchers at the National Institute of Standards and Technology (NIST) have demonstrated the use of an ultrafast laser "frequency comb" system for improved remote measurements of distance and vibration. The technology, described in a forthcoming issue of Optics Letters,* may have applications in automated manufacturing or defense systems because it enables uncommonly precise characterization of the range profile and motion of a surface.

The NIST laboratory system is an adaptation of light detection and ranging (LIDAR), which transmits light through the air to a target and analyzes the weak reflected signal to measure the distance, or range, to the target and other parameters. The NIST system uses an infrared laser that emits a continuous train of very brief, closely spaced pulses of light of a number of colors, or frequencies. An analysis of the frequencies reveals a very fine "comb" of evenly spaced teeth. The short pulse length (quadrillionths of a second, or millionths of a billionth of a second) creates a wide range of comb frequencies, enabling more accurate range measurements; the inherent stability of the laser creates fine comb teeth, enabling very precise vibration measurements.

The frequency comb serves as both the light source and as a precise ruler for measuring the reflected signal. NIST-developed software analyzes the intensity of the reflected signal to measure distance to the target, and analyzes the frequency (or Doppler) shift to measure vibration. The most unusual aspect of the system is the way it resolves common problems with signal "noise" and dispersion of light by the atmosphere into longer pulses (with different colors of light traveling at different speeds). The reflected light that is detected is divided into many different color bands for computer processing. Measurements are averaged across the channels, effectively multiplying the precision of the result by the number of channels.........

Posted by: Kevin      Permalink


February 9, 2006, 10:39 PM CT

Stable Polymer Nanotubes

Researchers at the National Institute of Standards and Technology (NIST) have created polymer nanotubes that are uncommonly long (about 1 centimeter) as well as stable enough to maintain their shape indefinitely. Described in a new paper in Proceedings of the National Academy of Sciences,* the NIST nanotubes may have biotechnology applications as channels for tiny volumes of chemicals in nanofluidic reactor devices, for example, or as the "world's smallest hypodermic needles" for injecting molecules one at a time.

Carbon nanotubes are of keen interest in nanotechnology research, particularly for making ultrastrong fibers and other structures. Nanotubes made from other materials are used for transport in biochemical applications, but are typically fragile and commonly collapse within a few hours. The NIST team developed processes for extending the shelf life of polymer nanotubes-considered essential for commercial applications-and forming sturdy nanotube network structures.

First the scientists made tiny, fluid-filled spherical containers with bi-layer membranes consisting of polymers with one end that likes water and one end that does not. (These fluid-filled containers are a spin-off of liposomes, artificial cells with fatty membranes used in cosmetics and for drug delivery.) The scientists made the membranes stretchy by adding a soap-like fluid to change the polymer membranes' mechanical properties. Then they used "optical tweezers" (highly focused infrared lasers) or tiny droppers called micropipettes to pull on the elastic membranes to form long, double-walled tubes that are less than 100 nanometers in diameter.........

Posted by: Kevin      Permalink

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