August 3, 2007, 10:02 PM CT

Thousands of Atoms Swap 'Spins' in Quantum Square Dance

Physicists at the National Institute of Standards and Technology (NIST) have induced thousands of atoms trapped by laser beams to swap "spins" with partners simultaneously. The repeated exchanges, like a quantum version of swinging your partner in a square dance but lasting a total of just 10 milliseconds, might someday carry out logic operations in quantum computers, which theoretically could quickly solve certain problems that today's best supercomputers could not solve in years.

The atomic dance, described in the July 26 issue of Nature,* advances prospects for the use of neutral atoms as quantum bits (qubits) for storing and processing data in quantum computers. Thanks to the peculiarities of quantum mechanics, nature's rule book for the smallest particles of matter and light, quantum computers might provide extraordinary power for applications such as breaking today's most widely used encryption codes. Neutral atoms are among about a dozen systems being reviewed around the world as qubits; their weak interactions with the environment may help to reduce computing errors.

The NIST experiments demonstrated the essential part of a so-called swap operation, in which atom partners exchange their internal spin states, trading an "up" spin (notionally a binary 1) for a "down" spin (binary 0.) Unlike classical bits, which would either swap or not, quantum bits can be simultaneously in an unusual state of having swapped and not swapped at the same time. Under these conditions, spin swapping has the effect of "entangling" the pairs, a quantum phenomenon that links the atoms' properties even when they are physically separated. Entanglement is one of the features that make quantum computers potentially so powerful. The swapping process is a way of creating logical connections among data, crucial in any computer......... Posted by: Sarah      Read more         Source

August 3, 2007, 9:58 PM CT

Nano-'Building Blocks' To Take On New Shapes

Scientists from the University of Delaware and Washington University in St. Louis have figured out how to train synthetic polymer molecules to behave--to literally "self-assemble" --and form into long, multicompartment cylinders 1,000 times thinner than a human hair, with potential uses in radiology, signal communication and the delivery of therapeutic drugs in the human body.

The discovery, a fundamental new tool for nanotechnology, is published in the Aug. 3 issue of the prestigious journal Science.

Darrin Pochan, associate professor of materials science and engineering at the University of Delaware, and Karen Wooley, the James S. McDonnell Distinguished Professor of Arts & Sciences at Washington University in St. Louis, led the research effort, which also involved co-authors Honggang Cui, a recent doctoral graduate, and doctoral student Sheng Zhong at UD, and Zhiyun Chen, a doctoral advisee of Wooley's. The research was supported by a Nanoscale Interdisciplinary Research Team (NIRT) grant from the National Science Foundation.

The focus of the research was block copolymers, which are synthetic molecules that contain two or more chemically different segments bonded together. Block copolymers are used to make a variety of materials such as plastics, rubber soles for shoes, and more recently, portable memory sticks ("flash drives") for computers......... Posted by: Kevin      Read more         Source

August 3, 2007, 9:52 PM CT

Explorers' Limited Ability To Navigate

When explorers like Magellan and Columbus sailed from Europe to the New World 500 years ago, they amazingly managed to navigate the open sea without terrestrial landmarks, natural boundaries or the navigational technology we have today.

Historical reports show that some explorers and other seafaring people did so by imagining an island just over the horizon; if they kept track of where the "virtual island" was, they knew which direction to go in the open water.

But new research from the University of Iowa suggests that people's ability to imagine virtual islands -- without any perceptual cues to help -- is quite limited. Consistent with this, studies of how seafaring people navigate on the open seas suggest they actually rely on two key perceptual cues: perception of their own motion and the boat's motion. Thus, the ability to navigate in open water stems from how the body senses motion, not on a mental ability to imagine a point.

In a paper published this month in the Journal of Experimental Psychology: Human Perception and Performance, doctoral candidate Vanessa Simmering and associate professor John Spencer, both of the Department of Psychology in the UI College of Liberal Arts and Sciences, provide evidence that adults cannot arbitrarily carve the world into spatial regions. Instead, they write, people must rely on perceptual cues for help. The paper is titled "Carving Up Space at Imaginary Joints: Can People Mentally Impose Arbitrary Spatial Category Boundaries?"......... Posted by: Tyler      Read more         Source

August 3, 2007, 9:44 PM CT

Ttechnology to monitor bridge safety

Greensboro North Carolina A &T State University has developed a technology that could have possibly prevented the bridge collapse in Minneapolis, Minnesota.

Dr. Mannur Sundaresan, professor of mechanical engineering, has developed a single channel continuous sensor that has the potential to detect and locate early crack growth in structures, thereby providing timely information to prevent catastrophic failures. This single channel continuous sensor can detect the leading edge of the acoustic emission event, occurring anywhere in the region covered by the sensor.

Essentially, the technology involves using commercially available sensors deployed in a unique configuration to acoustically monitor structural integrity to remotely detect and address standard flaws via acoustic emission signals.

As per Sundaresan the technology operates like the bodys nervous system. If youre hurt, the nervous system lets you know right away. That doesnt happen with a structure. An inspector has to go look. With small cracks, its like finding a needle in a haystack. Small cracks are like cancer. Theyre commonly not noticed until theyve grown large enough to cause serious damage. These sensors will detect the growth of cracks in their early stages just as our nervous system alerts us of any injury immediately so that we can take action to limit the damage......... Posted by: Kevin      Read more         Source

August 3, 2007, 5:15 AM CT

New oxidation methods streamline synthesis

One of the fundamental challenges facing organic synthesis in the 21st century is the need to significantly increase the efficiency with which carbon frameworks can be constructed and functionalized. Chemists at the University of Illinois are helping to meet this challenge by developing a class of carbon-hydrogen catalysts that are highly selective, reactive and tolerant of other functionality.

The catalysts also offer a new strategy for streamlining the synthesis of important compounds, including drugs and pharmaceuticals, by avoiding the functional group manipulations mandatory for working with oxidized materials.

"We are creating a toolbox of catalytic reactions that allow us to go directly from a carbon-hydrogen bond to a carbon-oxygen bond or to a carbon-nitrogen bond," said M. Christina White, a professor of chemistry at Illinois. "By offering fewer steps, fewer functional group manipulations and higher yields, this toolbox will change the way chemists make molecules".

Currently, chemists must make molecules by beginning with something that is already oxidized. But, having to start with that functionality means it must be carried - and protected - throughout the entire synthetic sequence. And that costs reagents, time, money and manpower, in addition to being inherently inefficient......... Posted by: Sarah      Read more         Source

August 1, 2007, 9:13 PM CT

Using a magnet to tune a magnet

An international research team, led by researchers at the London Centre for Nanotechnology (LCN), has found a way to switch a materials magnetic properties from hard to soft and back again something which could lead to new ways of controlling electromagnetic devices. The research will appear in the journal Nature on August 2nd and shows how a magnet can be tuned by subjecting it to a second magnetic field, perpendicular to the original.

Magnets can be classified by their hard or soft magnetic properties. Hard magnets, sometimes called permanent magnets, have fixed or pinned domain walls which mean the material stays magnetised for a long time. Soft magnets have moveable domain walls that can be easily flipped. These materials exhibit impermanent magnetic properties.

Professor Gabriel Aeppli, Director of the LCN and a senior member of the research team, explained the significance of the research: Whether a magnet is hard or soft determines what you can use it for. Typically, you would use a permanent magnet to fix a note to the door of your refrigerator because you want it to stay there for a long time. Conversely, you might use a soft magnet in a motor or transformer because it would be better at adapting to the rapid changes in alternating current and would dissipate much less energy than a hard magnet......... Posted by: Kevin      Read more         Source

August 1, 2007, 9:01 PM CT

Pollution Amplifies Greenhouse Gas Warming Trends

Researchers have concluded that the global warming trend caused by the buildup of greenhouse gases is a major contributor to the melting of Himalayan and other tropical glaciers. Now a new analysis of pollution-filled "brown clouds" over south Asia by scientists at Scripps Institution of Oceanography at UC San Diego offers hope that the region may be able to arrest some of the alarming retreat of such glaciers by reducing its air pollution.

The team led by Scripps atmospheric chemistry professor V. Ramanathan describes findings that atmospheric brown clouds enhanced solar heating of the lower atmosphere by about 50 percent in a paper to be released in the Aug. 2 edition of the journal Nature. The combined heating effect of greenhouse gases and the brown clouds, which contain soot, trace metals and other particles from a growing cadre of urban, industrial and agricultural sources, is enough to account for the retreat of Himalayan glaciers observed in the past half century, the scientists concluded. The glaciers supply water to major Asian rivers including the Yangtze, Ganges and Indus. These rivers in turn comprise the chief water supply for billions of people in China, India and other south Asian countries.

"The rapid melting of these glaciers, the third-largest ice mass on the planet, if it becomes widespread and continues for several more decades, will have unprecedented downstream effects on southern and eastern Asia," the Nature article concluded......... Posted by: Tyler      Read more         Source

August 1, 2007, 8:38 PM CT

A Step Toward Advanced Sensors

Engineers at Purdue University have.

shown how to finely control the spectral properties of ultrafast light pulses, a step toward creating advanced sensors, more powerful communications technologies and more precise laboratory instruments.

The laser pulses could be likened to strobes used in high-speed photography to freeze fast-moving objects such as bullets or flying insects. These laser pulses, however, are millions of times faster than such strobes, with flashes lasting a trillionth or quadrillionth of a second - a picosecond or femtosecond, respectively.

The properties of the pulses, when represented on a graph, take on specific shapes that characterize the changing light intensity from the beginning to end of each pulse. Precisely controlling this intensity, which is called "pulse shaping," will enable scientists to tune the laser pulses to suit specific applications, said Andrew Weiner, Distinguished Professor of Electrical and Computer Engineering at Purdue.

Scientists at other institutions have developed ultrafast lasers producing trains of pulses that are split into hundreds of thousands of segments, with each segment representing a different portion of the spectrum making up a pulse. The segments are called "comb lines" because they resemble teeth on a comb when represented on a graph, and the entire pulse train is called a "femtosecond frequency comb." The 2005 Nobel Prize in physics was awarded to scientists who precisely controlled the frequencies of these comb lines and demonstrated applications correlation to advanced optical clocks, which could improve communications, enhance navigation systems and enable new experiments to test physics theory, among other possible uses......... Posted by: Kevin      Read more         Source

July 31, 2007, 9:42 PM CT

Chickens dieting to help Delaware's waterways

Dieting to lose weight and improve your health?

Millions of chickens in Delaware--one of the nation's top poultry producers--have been on a diet to reduce their impact on the environment and improve the health of the state's waterways, and it appears to be working.

Extensive research led by William Saylor, professor of animal and food sciences at the University of Delaware, has confirmed that Delaware chickens now digest more of the phosphorus, an essential nutrient, in their feed, thanks to the addition of a natural enzyme called phytase. As a result, about 23 percent less phosphorus is output in chicken manure.

So now when poultry litter is used to fertilize a farm field, a lot less phosphorus is available to potentially leach from the soil or be carried off in storm water to a river or bay.

And that's good news for waterways like Delaware's Inland Bays, where overloads of nutrients, particularly phosphorus and nitrogen, have contributed to serious water-quality problems, such as massive blooms of algae and fish kills.

To put it in perspective, in 2006, Delaware farmers produced over 269 million broiler chickens--1.8 billion pounds of poultry--valued at more than $739 million, according to the Delmarva Poultry Industry. Those chickens produced more than 280,000 tons of waste......... Posted by: Kevin      Read more         Source

July 30, 2007, 8:07 PM CT

Remote Sensing Symposium

The International Geoscience and Remote Sensing Symposium, entitled 'Sensing and Understanding our Planet,' took place from 23 to 27 July 2007 in Barcelona, Spain, bringing together more than 1400 participants. ESA personnel presented Earth Explorer missions, especially the upcoming Soil Moisture and Ocean Salinity mission aimed at advancing our knowledge of the water cycle.

The International Geoscience and Remote Sensing Symposium (IGARSS) is a major annual event sponsored by the Geoscience and Remote Sensing Society to bring scientists, engineers and community leaders from all over the world to discuss the latest research findings and up-to-date technology for better understanding Earth.

IGARSS 2007 General Chairman, Prof. Ignasi Corbella, said: "Information gathered by all sensors and techniques must be wisely used mainly to understand our Earth. This will improve prediction of natural disasters or global climate change and provide tools to mitigate their consequences.

"As experts on the leading-edge technologies of Earth Observation (EO), we should play a prominent role in achieving these goals. This is our contribution to the important task of assuring people of all around the world access to resources for their subsistence without endangering the fragile equilibrium of our planet"......... Posted by: Brooke      Read more         Source