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February 8, 2007, 8:48 PM CT

Cosmic graffiti artist

Cosmic graffiti artist
Astronomers from the University of Virginia and other institutions have observed that Enceladus, the sixth-largest moon of Saturn, is a "cosmic graffiti artist," pelting the surfaces of at least 11 other moons of Saturn with ice particles sprayed from its spewing surface geysers. This ice sandblasts the other moons, creating a reflective surface that makes them among the brightest bodies in the solar system (Enceladus, itself a ball of mostly ice, is the single most reflective body in our solar system).

"Enceladus' art is a work-in-progress, constantly altering the surfaces of other moons orbiting within this moon's beautiful swirl of ice particles," said Anne Verbiscer, a research scientist in the astronomy department at the University of Virginia and the study's lead investigator. "We've dubbed Enceladus a graffiti artist because of its ability to alter the appearance of the other moons".

A paper about her and her colleagues' findings appears in the Feb. 9 issue of the journal Science.

The ring of ice particles Enceladus forms around Saturn is known as the E-ring. At least 11 other moons orbit within the E-ring and are constantly subjected to high velocity collisions with Enceladus's icy wake.

A series of geysers at Enceladus's south pole continually erupt, ejecting ice particles, spewing a swirling wispy trail in the moon's wake and ultimately forming a cloudy ring of ice particles. The ring is added to over and over as Enceladus repeats its orbit. The particles may persist for thousands of years, until they collide with one of the embedded moons, including Enceladus as it flows through its own emissions.........

Posted by: Edwin      Read more         Source

February 7, 2007, 9:08 PM CT

Adaptation to global climate change

Adaptation to global climate change
Temperatures are rising on Earth, which is heating up the debate over global warming and the future of our planet, but what may be needed most to combat global warming is a greater focus on adapting to our changing planet, says a team of science policy experts writing in this week's Nature magazine.

While a number of consider it taboo, adaptation to global climate change needs to be recognized as just as important as "mitigation," or cutting back, of greenhouse gases humans pump into Earth's atmosphere. The science policy experts, writing in the Feb. 8, 2007 issue of Nature, say adapting to the changing climate by building resilient societies and fostering sustainable development would go further in securing a future for humans on a warming planet than just cutting gas emissions.

"New ways of thinking about, talking about and acting on climate change are necessary if a changing society is to adapt to a changing climate," the scientists state in "Lifting the Taboo on Adaptation."

The policy experts include Daniel Sarewitz, director of Arizona State University's Consortium for Science, Policy & Outcomes; Roger Pielke Jr., University of Colorado, Boulder; Gwyn Prins, London School of Economics, London, England, and Columbia University, New York; and Steve Rayner of the James Martin Institute at Oxford University, Oxford, England.........

Posted by: Nora      Read more         Source

February 7, 2007, 9:05 PM CT

recasting usual view of elusive force

recasting usual view of elusive force JILA scientists measured how temperature affects the Casimir-Polder force using an apparatus that holds four small squares of glass inside a vacuum chamber.
Credit: E. Cornell group/JIL
Physicists at JILA have demonstrated that the warmer a surface is, the stronger its subtle ability to attract nearby atoms, a finding that could affect the design of devices that rely on small-scale interactions, such as atom chips, nanomachines, and microelectromechanical systems (MEMS).

The research highlights an underappreciated aspect of the elusive Casimir-Polder force, one of the stranger effects of quantum mechanics. The force arises from the ever-present random fluctuation of microscopic electric fields in empty space. The fluctuations get stronger near a surface, and an isolated neutral atom nearby will feel them as a subtle pulla flimsy, invisible rubber band between bulk objects and atoms that may be a source of friction, for example, in tiny devices. The JILA group previously made the most precise measurement ever of Casimir-Polder, measuring forces hundreds of times weaker than ever before and at greater distances (more than 5 micrometers). JILA is a joint institute of the National Institute of Standards and Technology (NIST) and the University of Colorado at Boulder.

Now, as reported in a paper scheduled for this week's issue of Physical Review Letters, the JILA team has made the first measurement of the temperature dependence of this force. By using a combination of temperatures at opposite extremesmaking a glass surface very hot while keeping the environment neutral and using ultracold atoms as a measurement toolthe new research underscores the power of surfaces to influence the Casimir-Polder force. That is, electric fields within the glass mostly reflect inside the surface but also leak out a little bit to greatly strengthen the fluctuations in neighboring space. As a result, says group leader and NIST Fellow Eric Cornell, "warm glass is stickier than cold glass".........

Posted by: John      Read more         Source

February 5, 2007, 7:22 PM CT

Nanoengineered Concrete To Cut Emissions

Nanoengineered Concrete To Cut Emissions MIT Professor Franz-Josef Ulm and post-doc Georgios Constantinides
Photo: Donna Covene
While government leaders argue about the practicality of reducing world emissions of carbon dioxide, researchers and engineers are seeking ways to make it happen.

One group of engineers at MIT decided to focus its work on the nanostructure of concrete, the world's most widely used material. The production of cement, the primary component of concrete, accounts for 5 to 10 percent of the world's total carbon dioxide emissions; the process is an important contributor to global warming.

In the recent issue of the Journal of the Mechanics and Physics of Solids, the team reports that the source of concrete's strength and durability lies in the organization of its nanoparticles. The discovery could one day lead to a major reduction in carbon dioxide emissions during manufacturing.

"If everything depends on the organizational structure of the nanoparticles that make up concrete, rather than on the material itself, we can conceivably replace it with a material that has concrete's other characteristics--strength, durability, mass availability and low cost--but does not release so much CO2 into the atmosphere during manufacture," said Professor Franz-Josef Ulm of civil and environmental engineering.

The work also shows that the study of very common materials at the nano scale has great potential for improving materials in ways we might not have conceived. Ulm refers to this work as the "identification of the geogenomic code of materials, the blueprint of a material's nanomechanical behavior".........

Posted by: John      Read more         Source

February 4, 2007, 8:20 PM CT

mammoth cloud engulfing Titan's North Pole

mammoth cloud engulfing Titan's North Pole Cassini's visual and infrared mapping spectrometer (VIMS) has imaged a huge cloud system covering the north pole of Titan.
A giant cloud half the size of the United States has been imaged on Saturn's moon Titan by the Cassini spacecraft. The cloud may be responsible for the material that fills the lakes discovered last year by Cassini's radar instrument.

Cloaked by winter's shadow, this cloud has now come into view as winter turns to spring. The cloud extends down to 60 degrees north latitude, is roughly 2400 kilometers in diameter and engulfs almost the entire north pole of Titan.

The new image was acquired on 29 December 2006, by Cassini's visual and infrared mapping spectrometer (VIMS). Scientific models predicted this cloud system but it had never been imaged with such details before.

"We knew this cloud had to be there but were amazed at its size and structure," said Dr. Christophe Sotin of the University of Nantes, France, a member of the visual and infrared mapping spectrometer team and distinguished visiting scientist at NASA's Jet Propulsion Laboratory, Pasadena, California. "This cloud system may be a key element in the global formation of organics and their interaction with the surface."

The same cloud system seen on 29 December 2006, was still there two weeks later during the flyby which took place on 13 January 2007, even though observing conditions were slightly less favorable than in December.........

Posted by: Edwin      Read more         Source

February 2, 2007, 4:54 AM CT

Miniaturized Device for Lab-on-a-Chip Separations

Miniaturized Device for Lab-on-a-Chip Separations Core of the new NIST miniature GEMBE chemical separation device
Scientists at the National Institute of Standards and Technology (NIST) have developed an elegantly simple, miniaturized technique for rapidly separating minute samples of proteins, amino acids and other chemical mixtures. A low-cost prototype device described in a recent paper* can run up to eight separations simultaneously in a space about the size of a quarter, highlighting the technique's potential for use in microfluidic "lab-on-a-chip" systems.

Conventional electrophoresis instruments separate mixtures of electrically charged species-DNA fragments, for example-by injecting a discrete sample of the mixture at one end of a chemical race track, such as a capillary tube filled with a buffer solution, and applying a high voltage between the sample and the other end of the track. Depending on their size, charge and chemical "mobility," the individual components of the mixture move down the track at different rates, gradually separating into individual bands. If two of the components move at very similar rates, it will require a relatively long channel-up to 50 centimeters or longer-to separate them effectively.

The new NIST technique, "gradient elution moving boundary electrophoresis" (GEMBE), works instead by opposing the movement of the mixture's components with a stream of buffering solution flowing at a variable rate. Like salmon swimming upstream, only the most mobile components can move up the channel against the highest buffer flow rates, but as that flow is reduced gradually, lesser mobility components begin to move. A sensor placed over the channel detects each new component as it arrives,.........

Posted by: John      Read more         Source

February 2, 2007, 4:32 AM CT

Rapid Method for Judging Nanotube Purity

Rapid Method for Judging Nanotube Purity
Scientists at the National Institute of Standards and Technology (NIST) have developed a sensitive new method for rapidly assessing the quality of carbon nanotubes. Initial feasibility tests show that the method not only is faster than the standard analytic technique but also effectively screens much smaller samples for purity and consistency and better detects sample variability.

Carbon nanotubes have unique properties, and thermal and electrical conductance, that could be useful in fields such as aerospace, microelectronics and biotechnology. However, these properties may vary widely depending on nanotube dimensions, uniformity and chemical purity. Nanotube samples typically contain a significant percentage of more ordinary forms of carbon as well as metal particles left over from catalysts used in manufacturing. The new NIST method, described at a conference last week,* involves spraying nanotube coatings onto a quartz crystal, gradually heating the coated crystal, and measuring the change in its resonant frequency as different forms of carbon vaporize. The frequency changes in proportion to the mass of the coating, and researchers use this as a measure of stability at different temperatures to gauge consistency among samples. The quartz crystal technique, which can reveal mass changes of just a few nanograms, already is used in other contexts to detect toxic gases and measure molecular interactions.........

Posted by: John      Read more         Source

February 1, 2007, 8:00 PM CT

UFO Pendant Lamp

Neues Licht uses glass fiber instead of LEDs to make this UFO (Unidentified Flying Object) pendant lamp, which is seen floating on the ceiling with its glass fiber focusing at the center of the disk like an energy beam.

The UFO measures diameter of 59cm and height around 20cm. If you are bored of same light color then u can easily change the color of the light.

"The light radiates from the glass spaghettis, propagates through the transparent disk, illuminating the whole system with a bright but eye-harmful light." (Cocolico).

The lamp produces same light as LEDs do, which can be harmful for our eyes. This makes the lamp not a good deal for the consumers.

But there are a number of goodies about the lamp and is different from electrical lamp. Above shown is the UFO lamp under water at Munich's Sealife aquarium.

After UFO, you will find all-optical Anemone and Scintilla chandelier in queue.........

Posted by: John      Read more         Source

January 30, 2007, 9:23 PM CT

What Causes Highly Dynamic Aurora

What Causes Highly Dynamic Aurora
On a clear night over the far northern areas of the world, you may witness a hauntingly beautiful light display in the sky that can disrupt your satellite TV and leave you in the dark.

The eerie glow of the northern lights seems exquisite and quite harmless. Most times, it is harmless. The display, resembling a slow-moving ribbon silently undulating in the sky, is called the aurora. It is also visible in far southern regions around the South Pole.

Occasionally, however, the aurora becomes much more dynamic. The single auroral ribbon may split into several ribbons or even break into clusters that race north and south. This dynamic light show in the polar skies is associated with what scientists call a magnetospheric substorm. Substorms are very closely related to full-blown space storms that can disable spacecraft, radio communication, GPS navigation, and power systems while supplying killer electrons to the radiation belts surrounding Earth. The purpose of NASA's Time History of Events and Macroscale Interactions during Substorms (THEMIS) mission is to understand the physical instability (trigger mechanism) for magnetospheric substorms.

A clash of forces we can't see with the human eye causes the beauty and destruction of space storms, though the aurora provides a dramatic symptom. Earth's molten iron core generates an invisible magnetic field that surrounds our planet. This magnetic field and the electrically charged matter under its control compose the Earth's magnetosphere.........

Posted by: Nora      Read more         Source

January 30, 2007, 7:35 PM CT

Molecular Motors and Brakes

Molecular Motors and Brakes Daughter microtubule (red) being formed on mother microtubule (red), within yeast cell (dashed line).
Image Credit: Phong Tran, PhD, University of Pennsylvania School of Medicine
Researchers at the University of Pennsylvania School of Medicine have discovered that microtubules - components responsible for shape, movement, and replication within cells - use proteins that act as molecular motors and brakes to organize into their correct structure. If microtubules are not formed properly such basic functions as cell division and transport can go wrong, which may have implications in such disease processes as cancer and dementia. The study, published in the recent issue of Cell, is featured on the cover of that issue.

"Up until now motors and brakes were studied separately from microtubules," says senior author Phong Tran, PhD, Assistant Professor of Cell and Developmental Biology. "This study lets us have a more complete picture".

Microtubules are structures that help give shape to many types of cells, form the spindle (view video below) - a structure important in cell division - and act as a railroad, of sorts, upon which molecular motors move protein packages for waste removal and nerve transmission.

In the Cell study, the investigators, working with fission yeast cells, showed that stable end-to-end arrays of microtubules can be achieved by a balance between the sliding by a molecular motor called klp2p and the braking of a microtubule-associated protein (MAP) called ase1p. Specifically, they showed that a preexisting "mother" microtubule acts as a platform on which a new microtubule can be formed (view video below). The new "daughter" microtubule grows and moves along the mother microtubule. In time, the daughter grows beyond the end of the mother to ultimately produce two microtubules, connected by the cross-linking MAP ase1p.........

Posted by: Nora      Read more         Source

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