KnK Decoration

Schizophrenia: Costly By-product Of Human Brain Evolution?

2008-08-25T12:52:00.000-07:00

ScienceDaily (Aug. 5, 2008) — Metabolic changes responsible for the evolution of our unique cognitive abilities indicate that the brain may have been pushed to the limit of its capabilities. Research published today in BioMed Central's open access journal Genome Biology adds weight to the theory that schizophrenia is a costly by-product of human brain evolution.

Philipp Khaitovich, from the Max-Planck-Institute for Evolutionary Anthropology and the Shanghai branch of the Chinese Academy of Sciences, led a collaboration of researchers from Cambridge, Leipzig and Shanghai who investigated brains from healthy and schizophrenic humans and compared them with chimpanzee and rhesus macaque brains. The researchers looked for differences in gene expression and metabolite concentrations and, as Khaitovich explains, "identified molecular mechanisms involved in the evolution of human cognitive abilities by combining biological data from two research directions: evolutionary and medical".

The idea that certain neurological diseases are by-products of increases in metabolic capacity and brain size that occurred during human evolution has been suggested before, but in this new work the authors used new technical approaches to really put the theory to the test.

They identified the molecular changes that took place over the course of human evolution and considered those molecular changes observed in schizophrenia, a psychiatric disorder believed to affect cognitive functions such as the capacities for language and complex social relationships. They found that expression levels of many genes and metabolites that are altered in schizophrenia, especially those related to energy metabolism, also changed rapidly during evolution. According to Khaitovich, "Our new research suggests that schizophrenia is a by-product of the increased metabolic demands brought about during human brain evolution".

The authors conclude that this work paves the way for a much more detailed investigation. "Our brains are unique among all species in their enormous metabolic demand. If we can explain how our brains sustain such a tremendous metabolic flow, we will have a much better chance to understand how the brain works and why it sometimes breaks", said Khaitovich.

Journal reference:

1. Khaitovich et al. Metabolic changes in schizophrenia and human brain evolution. Genome Biology, 2008 (in press) [link]

Adapted from materials provided by BioMed Central, via EurekAlert!, a service of AAAS.

Converting Sunlight To Cheaper Energy

2008-08-25T12:28:00.000-07:00

ScienceDaily (Aug. 25, 2008) — Scientists are working to convert sunlight to cheap electricity at South Dakota State University. Research scientists are working with new materials that can make devices used for converting sunlight to electricity cheaper and more efficient.

Assistant professor Qiquan Qiao in SDSU’s Department of Electrical Engineering and Computer Science said so-called organic photovoltaics, or OPVs, are less expensive to produce than traditional devices for harvesting solar energy.

Qiao and his SDSU colleagues also are working on organic light-emitting diodes, or OLEDs.

The new technology is sometimes referred to as “molecular electronics” or “organic electronics” — organic because it relies on carbon-based polymers and molecules as semiconductors rather than inorganic semiconductors such as silicon.

“Right now the challenge for photovoltaics is to make the technology less expensive,” Qiao said.

“Therefore, the objective is find new materials and novel device structures for cost-effective photovoltaic devices.

“The beauty of organic photovoltaics and organic LEDs is low cost and flexibility,” the researcher continued. “These devices can be fabricated by inexpensive, solution-based processing techniques similar to painting or printing."

“The ease of production brings costs down, while the mechanical flexibility of the materials opens up a wide range of applications,” Qiao concluded.

Organic photovoltaics and organic LEDs are made up of thin films of semiconducting organic compounds that can absorb photons of solar energy. Typically an organic polymer, or a long, flexible chain of carbon-based material, is used as a substrate on which semiconducting materials are applied as a solution using a technique similar to inkjet printing.

“The research at SDSU is focused on new materials with variable band gaps,” Qiao said.

“The band gap determines how much solar energy the photovoltaic device can absorb and convert into electricity.”

Qiao explained that visible sunlight contains only about 50 percent of the total solar energy. That means the sun is giving off just as much non-visible energy as visible energy.

“We’re working on synthesizing novel polymers with variable band gaps, including high, medium and low-band gap varieties, to absorb the full spectrum of sunlight. By this we can double the light harvesting or absorption,” Qiao said.

SDSU’s scientists plan to use the variable band gap polymers to build multi-junction polymer solar cells or photovoltaics.

These devices use multiple layers of polymer/fullerene films that are tuned to absorb different spectral regions of solar energy.

Ideally, photons that are not absorbed by the first film layer pass through to be absorbed by the following layers.

The devices can harvest photons from ultraviolet to visible to infrared in order to efficiently convert the full spectrum of solar energy to electricity.

SDSU scientists also work with organic light-emitting diodes focusing on developing novel materials and devices for full color displays.

“We are working to develop these new light-emitting and efficient, charge-transporting materials to improve the light-emitting efficiency of full color displays,” Qiao said.

Currently, LED technology is used mainly for signage displays. But in the future, as OLEDs become less expensive and more efficient, they may be used for residential lighting, for example.

The new technology will make it easy to insert lights into walls or ceilings. But instead of light bulbs, the lighting apparatus of the future may look more like a poster, Qiao said.

Qiao and his colleagues are funded in part by SDSU’s electrical engineering Ph.D. program and by National Science Foundation and South Dakota EPSCoR, the Experimental Program to Stimulate Competitive Research.

In addition Qiao is one of about 40 faculty members from SDSU, the South Dakota School of Mines and Technology and the University of South Dakota who have come together to form Photo Active Nanoscale Systems (PANS).

The primary purpose is developing photovoltaics, or devices that will directly convert light to electricity.
Adapted from materials provided by South Dakota State University, via Newswise.

New 'Nano-positioners' May Have Atomic-scale Precision

2008-08-21T12:38:00.000-07:00

ScienceDaily (Aug. 21, 2008) — Engineers have created a tiny motorized positioning device that has twice the dexterity of similar devices being developed for applications that include biological sensors and more compact, powerful computer hard drives.

The device, called a monolithic comb drive, might be used as a "nanoscale manipulator" that precisely moves or senses movement and forces. The devices also can be used in watery environments for probing biological molecules, said Jason Vaughn Clark, an assistant professor of electrical and computer engineering and mechanical engineering, who created the design.

The monolithic comb drives could make it possible to improve a class of probe-based sensors that detect viruses and biological molecules. The sensors detect objects using two different components: A probe is moved while at the same time the platform holding the specimen is positioned. The new technology would replace both components with a single one - the monolithic comb drive.

The innovation could allow sensors to work faster and at higher resolution and would be small enough to fit on a microchip. The higher resolution might be used to design future computer hard drives capable of high-density data storage and retrieval. Another possible use might be to fabricate or assemble miniature micro and nanoscale machines.

Research findings were detailed in a technical paper presented in July during the University Government Industry Micro/Nano Symposium in Louisville. The work is based at the Birck Nanotechnology Center at Purdue's Discovery Park.

Conventional comb drives have a pair of comblike sections with "interdigitated fingers," meaning they mesh together. These meshing fingers are drawn toward each other when a voltage is applied. The applied voltage causes the fingers on one comb to become positively charged and the fingers on the other comb to become negatively charged, inducing an attraction between the oppositely charged fingers. If the voltage is removed, the spring-loaded comb sections return to their original position.

By comparison, the new monolithic device has a single structure with two perpendicular comb drives.

Clark calls the device monolithic because it contains comb drive components that are not mechanically and electrically separate. Conventional comb drives are structurally "decoupled" to keep opposite charges separated.

"Comb drives represent an advantage over other technologies," Clark said. "In contrast to piezoelectric actuators that typically deflect, or move, a fraction of a micrometer, comb drives can deflect tens to hundreds of micrometers. And unlike conventional comb drives, which only move in one direction, our new device can move in two directions - left to right, forward and backward - an advance that could really open up the door for many applications."

Clark also has invented a way to determine the precise deflection and force of such microdevices while reducing heat-induced vibrations that could interfere with measurements.

Current probe-based biological sensors have a resolution of about 20 nanometers.

"Twenty nanometers is about the size of 200 atoms, so if you are scanning for a particular molecule, it may be hard to find," Clark said. "With our design, the higher atomic-scale resolution should make it easier to find."

Properly using such devices requires engineers to know precisely how much force is being applied to comb drive sensors and how far they are moving. The new design is based on a technology created by Clark called electro micro metrology, which enables engineers to determine the precise displacement and force that's being applied to, or by, a comb drive. The Purdue researcher is able to measure this force by comparing changes in electrical properties such as capacitance or voltage.

Clark used computational methods called nodal analysis and finite element analysis to design, model and simulate the monolithic comb drives.

The research paper describes how the monolithic comb drive works when voltage is applied. The results show independent left-right and forward-backward movement as functions of applied voltage in color-coded graphics.

The findings are an extension of research to create an ultra-precise measuring system for devices having features on the size scale of nanometers, or billionths of a meter. Clark has led research to create devices that "self-calibrate," meaning they are able to precisely measure themselves. Such measuring methods and standards are needed to better understand and exploit nanometer-scale devices.

The size of the entire device is less than one millimeter, or a thousandth of a meter. The smallest feature size is about three micrometers, roughly one-thirtieth as wide as a human hair.

"You can make them smaller, though," Clark said. "This is a proof of concept. The technology I'm developing should allow researchers to practically and efficiently extract dozens of geometric and material properties of their microdevices just by electronically probing changes in capacitance or voltage."

In addition to finite element analysis, Clark used a simulation tool that he developed called Sugar.

"Sugar is fast and allows me to easily try out many design ideas," he said. "After I narrow down to a particular design, I then use finite element analysis for fine-tuning. Finite element analysis is slow, but it is able to model subtle physical phenomena that Sugar doesn't do as well."

Clark's research team is installing Sugar on the nanoHub this summer, making the tool available to other researchers. The nanoHub is operated by the Network for Computational Nanotechnology, funded by the National Science Foundation and housed at Purdue's Birck Nanotechnology Center.

The researchers also are in the process of fabricating the devices at the Birck Nanotechnology Center.
Adapted from materials provided by Purdue University.

Energy Storage For Hybrid Vehicles

2008-08-21T12:34:00.000-07:00

ScienceDaily (Aug. 18, 2008) — Hybrid technology combines the advantages of combustion engines and electric motors. Scientists are developing high-performance energy storage units, a prerequisite for effective hybrid motors.

The vehicle is powered by petroleum on the freeway and by electricity in town, thus using considerably less energy. A hybrid propulsion system switches over to generator operation when the brakes go on, producing electric current that is temporarily stored in a battery. The electric motor uses this current when starting up. This yields tremendous savings, particularly in urban traffic.

But up to now, hybrid technology has always had a storage problem. Scientists from three Fraunhofer Institutes are developing new storage modules in a project called “Electromobility Fleet Test”.

The pilot project was launched by Volkswagen and Germany’s Federal Ministry for the Environment BMU together with seven other partners. The Fraunhofer Institutes for Silicon Technology ISIT in Itzehoe, Integrated Circuits IIS in Nuremberg, and Integrated Systems and Device Technology IISB in Erlangen will be pooling their expertise for the next three years. The researchers are developing an energy storage module based on lithium-polymer accumulator technology that is suitable for use in vehicles.

“This module has to be able to withstand the harsh environmental conditions it will encounter in a hybrid vehicle, and above all it must guarantee high operational reliability and a long service life,” states ISIT scientist Dr. Gerold Neumann, who coordinates the Fraunhofer activities. The researchers hope to reach this goal with new electrode materials that are kinder to the environment.

A specially developed battery management system makes the energy storage device more durable and reliable. The experts are also researching into new concepts that will enable large amounts of energy to be stored in a small space. To do this, they integrate mechanical and electrical components in a single module, devising systems for temperature control, performance data registration and high-voltage safety.

The tasks involved are distributed between the three Fraunhofer Institutes according to their skills: The ISIT experts, who have long experience in developing and manufacturing lithium accumulators, are manufacturing the cells. Their colleagues at IIS are responsible for battery management and monitoring. The scientists from IISB are contributing their know-how on power electronics components to configure the accumulator modules. The development and configuration of the new energy storage module is expected to be finished by mid-2010. Volkswagen AG – the industrial partner in this project – will then carry out field trials to test the modules’ suitability for everyday use in the vehicles.
Adapted from materials provided by Fraunhofer-Gesellschaft.

Large Hadron Collider Set To Unveil A New World Of Particle Physics

2008-08-21T12:27:00.000-07:00

ScienceDaily (Aug. 21, 2008) — The field of particle physics is poised to enter unknown territory with the startup of a massive new accelerator--the Large Hadron Collider (LHC)--in Europe this summer. On September 10, LHC scientists will attempt to send the first beam of protons speeding around the accelerator.

The LHC will put hotly debated theories to the test as it generates a bonanza of new experimental data in the coming years. Potential breakthroughs include an explanation of what gives mass to fundamental particles and identification of the mysterious dark matter that makes up most of the mass in the universe. More exotic possibilities include evidence for new forces of nature or hidden extra dimensions of space and time.

"The LHC is a discovery machine. We don't know what we'll find," said Abraham Seiden, professor of physics and director of the Santa Cruz Institute for Particle Physics (SCIPP) at the University of California, Santa Cruz.

SCIPP was among the initial group of institutions that spearheaded U.S. participation in the LHC. About half of the entire U.S. experimental particle-physics community has focused its energy on the ATLAS and CMS detectors, the largest of four detectors where experiments will be performed at the LHC. SCIPP researchers have been working on the ATLAS project since 1994. It is one of many international physics and astrophysics projects that have drawn on SCIPP's 20 years of experience developing sophisticated technology for tracking high-energy subatomic particles.

The scale of the LHC is gigantic in every respect--its physical size, the energies attained, the amount of data it will generate, and the size of the international collaboration involved in its planning, construction, and operation. In September, high-energy beams of protons will begin circulating around the LHC's 27-kilometer (16.8-mile) accelerator ring located 100 meters (328 feet) underground at CERN, the European particle physics lab based in Geneva, Switzerland. After a period of testing, the beams will cross paths inside the detectors and the first collisions will take place.

Even before the machine is ramped up to its maximum energy early next year, it will smash protons together with more energy than any previous collider. The debris from those collisions--showers of subatomic particles that the detectors will track and record--will yield results that could radically change our understanding of the physical world.

In a talk at the American Physical Society meeting earlier this year, Seiden gave an overview of the LHC research program, including a rough timeline for reaching certain milestones. One of the most highly anticipated milestones, for example, is detection of the Higgs boson, a hypothetical particle that would fill a major gap in the standard model of particle physics by endowing fundamental particles with mass. Detection of the Higgs boson is most likely to occur in 2010, Seiden said.

But there's no guarantee that the particle actually exists; nature may have found another way to create mass. "I'm actually hoping we find something unexpected that does the job of the Higgs," Seiden said.

Technically, the Higgs boson was postulated to explain a feature of particle interactions known as the breaking of electroweak symmetry, and the LHC is virtually guaranteed to explain that phenomenon, according to theoretical physicist Howard Haber.

"We've been debating this for 30 years, and one way or another, the LHC will definitively tell us how electroweak symmetry breaking occurs. That's a fundamental advance," said Haber, a professor of physics at UCSC.

Haber and other theorists have spent years imagining possible versions of nature, studying their consequences, and describing in detail what the evidence would look like in the experimental data from a particle accelerator such as the LHC. The Higgs boson won't be easy to find, he said. The LHC should produce the particles in abundance (if they exist), but most of them will not result in a very distinctive signal in the detectors.

"It's a tough game. You can only do it by statistical analysis, since there are other known processes that produce events that can mimic a Higgs boson signal," Haber said.

Evidence to support another important theory--supersymmetry--could show up sooner. In many ways, supersymmetry is a more exciting possibility than the Higgs boson, according to theorist Michael Dine, also a professor of physics at UCSC.

"By itself, the Higgs is a very puzzling particle, so there have been a lot of conjectures about some kind of new physics beyond the standard model. Supersymmetry has the easiest time fitting in with what we know," Dine said.

Adding to its appeal, supersymmetry predicts the existence of particles that are good candidates to account for dark matter. Astronomers have detected dark matter through its gravitational effects on stars and galaxies, but they don't yet know what it is. Particles predicted by supersymmetry that could account for dark matter may be identified at the LHC as early as next year, Seiden said.

"Initially, we'll be looking for things that are known standards to make sure that everything is working properly. In 2009, we could start really looking for new things like supersymmetry," he said.

The massive ATLAS detector--45 meters (148 feet) long and 25 meters (82 feet) high--has involved more than 2,000 physicists at 166 institutions. Seiden's team at SCIPP has been responsible for developing the silicon sensors and electronics for the detector's inner tracker, which measures the trajectories of charged particles as they first emerge from the site of the collisions.

Seiden is now leading the U.S. effort to develop a major upgrade of ATLAS. The current detector is designed to last for 10 years, and the upgrade will coincide with a planned increase in the luminosity of the proton beams at the LHC (which will then become the "Super LHC").

"These large projects take such a long time, we have to start early," Seiden said.

Meanwhile, operation and testing of the current ATLAS detector is already under way at CERN, said Alexander Grillo, a SCIPP research physicist who has been working on the project from the start.

"We've been operating it and looking at cosmic ray particles," he said. "Nature gives us these cosmic rays for free, and they're the same kinds of particles we'll see when the machine turns on, so it enables us to check out certain aspects of the detector. But we're very excited to start seeing collisions from the machine."

ATLAS and the other LHC detectors are designed with "trigger" systems that ignore most of the signals and record only those events likely to yield interesting results. Out of the hundreds of millions of collisions happening every second inside the detector, only 100 of the most promising events will be selected and recorded in the LHC's central computer system.

"We'll be throwing away a lot of data, so we have to make sure the triggers are working correctly," Seiden said.

Grillo noted that the ATLAS project has been a great opportunity for UCSC students. Both graduate students and undergraduates have been involved in the development of the detector, along with postdoctoral researchers, research physicists, and senior faculty.

"The graduate students and postdocs get to go to Geneva, but even the undergraduates get a chance to work in a real physics lab and be part of a major international experiment," Grillo said.

SCIPP's prominent role in the LHC is also a boon for theoretical physicists at UCSC who are not directly involved in the collaboration, such as Dine, Haber, Thomas Banks, and others.

"There is a high level of interaction and camaraderie between theorists and experimentalists at UCSC, which is not the case at other leading institutions," Dine said. "For me, it's valuable just in terms of being aware of what's happening on the experimental side."

According to Haber, the LHC is certain to generate a lot of excitement in the world of physics.

"If nothing were found beyond what we know today, that would be so radical, because it would be in violation of a lot of extremely fundamental principles," he said.

More information about the LHC and U.S. involvement in the project is available at http://www.uslhc.us. Information about SCIPP is available at http://scipp.ucsc.edu.
Adapted from materials provided by University of California - Santa Cruz.

Whales And Dolphins Influence New Wind Turbine Design

2008-07-25T19:38:00.000-07:00

ScienceDaily (July 8, 2008) — Sea creatures have evolved over millions of years to maximise efficiency of movement through water; humans have been trying to perfect streamlined designs for barely a century. So shouldn't we be taking more notice of the experts?

Biologists and engineers from across the US have been doing just that. By studying the flippers, fins and tails of whales and dolphins, these scientists have discovered some features of their structure that contradict long-held engineering theories. Dr Frank Fish (West Chester University) will talk about the exciting impact that these discoveries may have on traditional industrial designs on July 8th at the Society for Experimental Biology's Annual Meeting in Marseille.

Some of his observations are already being applied to real life engineering problems, a concept known as biomimetics. The shape of whale flippers with one bumpy edge has inspired the creation of a completely novel design for wind turbine blades. This design has been shown to be more efficient and also quieter, but defies traditional engineering theories.

"Engineers have previously tried to ensure steady flow patterns on rigid and simple lifting surfaces, such as wings. The lesson from biomimicry is that unsteady flow and complex shapes can increase lift, reduce drag and delay 'stall', a dramatic and abrupt loss of lift, beyond what existing engineered systems can accomplish," Dr Fish advises. "There are even possibilities that this technology could be applied to aeronautical designs such as helicopter blades in the future."

The work centres on studies of vortices, tornado-shaped water formations that develop in the wake of the animals. "In the case of the humpback whale, vortices formed from tubercles (bumps) on the front edge of flippers help to generate more lift without the occurrence of stall, as well as enhancing manoeuvrability and agility," explains Dr Fish. "In the case of the tails of dolphins, vortices are formed at the end of the up and down strokes. These vortices are involved in the production of a jet in the wake of the dolphin that produces high thrust. By regulating the production of the vortices, the dolphin can maximize its efficiency while swimming."

This work was funded by the US National Science Foundation and the US Office of Naval Research.

Journal reference:

1. Fish et al. Hydrodynamic flow control in marine mammals. Integrative and Comparative Biology, 2008; DOI: 10.1093/icb/icn029

Adapted from materials provided by Society for Experimental Biology, via EurekAlert!, a service of AAAS.

New 'Window' Opens On Solar Energy: Cost Effective Devices Available Soon

2008-07-25T19:31:00.000-07:00

ScienceDaily (July 11, 2008) — Imagine windows that not only provide a clear view and illuminate rooms, but also use sunlight to efficiently help power the building they are part of. MIT engineers report a new approach to harnessing the sun's energy that could allow just that.

The work, reported in the July 11 issue of Science, involves the creation of a novel "solar concentrator." "Light is collected over a large area [like a window] and gathered, or concentrated, at the edges," explains Marc A. Baldo, leader of the work and the Esther and Harold E. Edgerton Career Development Associate Professor of Electrical Engineering.

As a result, rather than covering a roof with expensive solar cells (the semiconductor devices that transform sunlight into electricity), the cells only need to be around the edges of a flat glass panel. In addition, the focused light increases the electrical power obtained from each solar cell "by a factor of over 40," Baldo says.

Because the system is simple to manufacture, the team believes that it could be implemented within three years--even added onto existing solar-panel systems to increase their efficiency by 50 percent for minimal additional cost. That, in turn, would substantially reduce the cost of solar electricity.

In addition to Baldo, the researchers involved are Michael Currie, Jon Mapel, and Timothy Heidel, all graduate students in the Department of Electrical Engineering and Computer Science, and Shalom Goffri, a postdoctoral associate in MIT's Research Laboratory of Electronics.

"Professor Baldo's project utilizes innovative design to achieve superior solar conversion without optical tracking," says Dr. Aravinda Kini, program manager in the Office of Basic Energy Sciences in the U.S. Department of Energy's Office of Science, a sponsor of the work. "This accomplishment demonstrates the critical importance of innovative basic research in bringing about revolutionary advances in solar energy utilization in a cost-effective manner."

Solar concentrators in use today "track the sun to generate high optical intensities, often by using large mobile mirrors that are expensive to deploy and maintain," Baldo and colleagues write in Science. Further, "solar cells at the focal point of the mirrors must be cooled, and the entire assembly wastes space around the perimeter to avoid shadowing neighboring concentrators."

The MIT solar concentrator involves a mixture of two or more dyes that is essentially painted onto a pane of glass or plastic. The dyes work together to absorb light across a range of wavelengths, which is then re-emitted at a different wavelength and transported across the pane to waiting solar cells at the edges.

In the 1970s, similar solar concentrators were developed by impregnating dyes in plastic. But the idea was abandoned because, among other things, not enough of the collected light could reach the edges of the concentrator. Much of it was lost en route.

The MIT engineers, experts in optical techniques developed for lasers and organic light-emitting diodes, realized that perhaps those same advances could be applied to solar concentrators. The result? A mixture of dyes in specific ratios, applied only to the surface of the glass, that allows some level of control over light absorption and emission. "We made it so the light can travel a much longer distance," Mapel says. "We were able to substantially reduce light transport losses, resulting in a tenfold increase in the amount of power converted by the solar cells."

This work was also supported by the National Science Foundation. Baldo is also affiliated with MIT's Research Laboratory of Electronics, Microsystems Technology Laboratories, and Institute for Soldier Nanotechnologies.

Mapel, Currie and Goffri are starting a company, Covalent Solar, to develop and commercialize the new technology. Earlier this year Covalent Solar won two prizes in the MIT $100K Entrepreneurship Competition. The company placed first in the Energy category ($20,000) and won the Audience Judging Award ($10,000), voted on by all who attended the awards.
Adapted from materials provided by Massachusetts Institute of Technology.

Solar Cooling Becomes A New Air-conditioning System

2008-07-25T19:21:00.000-07:00

ScienceDaily (July 20, 2008) — Scientists from the Universidad Carlos III of Madrid (UC3M) and the Consejo Superior de Investigaciones Científicas (CSIC) have developed an environmentally friendly cooling technology that does not harm the ozone layer. This is achieved by using solar energy and therefore reducing the use of greenhouse gases.

A research team has designed and built an absorption chiller capable of using solar and residual heat as an energy source to drive the cooling system. The technology used in this machine, which looks like an ordinary air-conditioning system, minimises its environmental impact by combining the use of a lithium bromide solution, which does not damage the ozone layer or increase the greenhouse effect, with a reduction in the use of water by the machine.

The team, managed by Professor Marcelo Izquierdo from the Department of Thermal Engineering and Fluid Mechanics of the UC3M, who is also a researcher at the Instituto de Ciencias de la Construcción Eduardo Torroja (IETCC) of the CSIC, is building a solar cooling system that unlike the existing machines on the market, uses an improved absorption mechanism capable of producing cold water at a range of temperatures from 7º C to 18º C when the exterior temperature ranges from 33º C to 43º C.

Residential use

Professor Marcelo Izquierdo states that the conclusions reached by a study with a commercial air condensed absorption machine prove that given an outside temperature ranging from 28ºC and 34ºC, the machine can produce cold water at a range of 12 to 16ºC, with a source temperature at the generator between 80ºC to 95ºC. Under these conditions, the cold water produced can be used for climate control applications in houses by combining it with a water-to-air heat exchanger (fan coil).

Quoting Raquel Lizarte, a researcher at the Department of Thermal Engineering and Fluid Mechanics of the UC3M, “There are few absorption machines at a commercial level that are adapted for residential use”, and since it is very hard to go without climate control, it is important to find a cooling technology that has minimal environmental impact. “The machine that we're studying produces enough cold water to cool down a room of 40 m2 of floor area and with a volume of 120 m3”, she states.

In 2007, 191 countries were involved in the Montreal protocol; a signed agreement to avoid the use of ozone depleting substances such as the HCFC refrigerants used in the air-conditioning industry as well as to set a limit such that by the year 2010 the energy consumption should be just 25% of the level that was allowed in 1996. Also, by the year 2020 all the HCFC refrigerants used in developed countries will have to be replaced with substitutes. This protocol makes research into this kind of technology extremely important for the near future.

The study has been published in the current edition of the magazine Applied Thermal Engineering under the title: ‘Air conditioning using an air-cooled single effect lithium bromide absorption chiller: Results of a trial conducted in Madrid in August 2005’. In this investigation scientists from the Universidad Carlos III of Madrid and Universidad Nacional de Educación a Distancia have collaborated under the coordination of the Instituto de Ciencias de la Construcción Eduardo Torroja-CSIC.
Adapted from materials provided by Universidad Carlos III de Madrid, via AlphaGalileo.

A Healthier July Fourth: Eco-friendly Fireworks And Flares Poised To Light Up The Sky

2008-07-04T10:53:00.000-07:00

ScienceDaily (July 3, 2008) — From the rockets' red glare to bombs bursting in air, researchers are developing more environmentally friendly fireworks and flares to light up the night sky while minimizing potential health risks, according to an article scheduled for the June 30 issue of Chemical & Engineering News. Some eco-friendly fireworks may soon appear at a Fourth of July display or rock concert near you.

In the C&EN cover story, Associate Editor Bethany Halford points out that fireworks, flares and other so-called pyrotechnics commonly include potassium perchlorate to speed up the fuel-burning process. But some studies have linked perchlorate, which can accumulate in the soil, air and water, to thyroid damage. Pyrotechnics also contain color-producing heavy metals, such as barium and copper, which have also been linked to toxic effects.

Researchers recently developed new pyrotechnic formulas that replace perchlorate with nitrogen-rich materials or nitrocellulose that burn cleaner and produce less smoke. At the same time, these nitrogen-rich formulas also use fewer color-producing chemicals, dramatically cutting down on the amount of heavy metals used and lowering their potentially toxic effects. Some of these fireworks are already being used at circuses, rock concerts, and other events.

The big challenge in developing these "eco-friendly" pyrotechnics is making them as cost-effective as conventional fireworks while maintaining their dazzle and glow, the article states.

Journal reference:

1. Bethany Halford. Pyrotechnics For The Planet: Chemists seek environmentally friendlier compounds and formulations for fireworks and flares. Chemical & Engineering News, June 30 2008 [link]

Adapted from materials provided by American Chemical Society, via EurekAlert!, a service of AAAS.

Getting Wrapped Up In Solar Textiles

2008-07-04T10:46:00.000-07:00

ScienceDaily (June 21, 2008) — Sheila Kennedy, an expert in the integration of solar cell technology in architecture who is now at MIT, creates designs for flexible photovoltaic materials that may change the way buildings receive and distribute energy.

These new materials, known as solar textiles, work like the now-familiar photovoltaic cells in solar panels. Made of semiconductor materials, they absorb sunlight and convert it into electricity.

Kennedy uses 3-D modeling software to design with solar textiles, generating membrane-like surfaces that can become energy-efficient cladding for roofs or walls. Solar textiles may also be draped like curtains.

"Surfaces that define space can also be producers of energy," says Kennedy, a visiting lecturer in architecture. "The boundaries between traditional walls and utilities are shifting."

Principal architect in the Boston firm, Kennedy & Violich Architecture, Ltd., and design director of its materials research group, KVA Matx, Kennedy came to MIT this year. She was inspired, she says, by President Susan Hockfield's plan to make MIT the "energy university" and by MIT's interdisciplinary energy curriculum that integrates research and practice.

This spring, Kennedy taught a new MIT architecture course, Soft Space: Sustainable Strategies for Textile Construction. She challenged the students to design architectural proposals for a new fast train station and public market in Porto, Portugal.

For Mary Hale, graduate student in architecture, Kennedy's Soft Space course was an inspiration to pursue photovoltaic technology in her master's thesis.

"I have always been interested in photovoltaics, but before this studio, I am not sure that I would have felt empowered to integrate them into a personal, self-propelled, project," she says.

Kennedy, for her part, will pursue her research in pushing the envelope of energy-efficiency and architecture. A recent project, "Soft House," exhibited at the Vitra Design Museum in Essen, Germany, illustrates what Kennedy means when she says the boundaries between walls and utilities are changing.

For Soft House, Kennedy transformed household curtains into mobile, flexible energy-harvesting surfaces with integrated solid-state lighting. Soft House curtains move to follow the sun and can generate up to 16,000 watt-hours of electricity--more than half the daily power needs of an average American household.

Although full-scale Soft House prototypes were successfully developed, the project points to a challenge energy innovators and other inventors face, Kennedy says. "Emerging technologies tend to under-perform compared with dominant mainstream technologies."

For example, organic photovoltaics (OPV), an emergent solar nano-technology used by the Soft House design team, are currently less efficient than glass-based solar technologies, Kennedy says.

But that lower efficiency needn't be an insurmountable roadblock to the marketplace, Kennedy says, because Soft House provides an actual application of the unique material advantages of solar nano-technologies without having to compete with the centralized grid.

Which brings her back to the hands-on, prototype-building approach Kennedy hopes to draw from in her teaching and work at MIT.

"Working prototypes are a very important demonstration tool for showing people that there are whole new ways to think about energy," she says.
Adapted from materials provided by Massachusetts Institute Of Technology. Original article written by Sarah H. Wright.

Goodbye To Batteries And Power Cords In Factories

2008-07-04T10:42:00.000-07:00

ScienceDaily (June 11, 2008) — A broken cable or a soiled connector? If a machine in a factory goes on strike, it could be for any of a thousand reasons. Self-sufficient sensors that provide their own power supply will soon make these machines more robust.

When a factory machine breaks down, it’s hard to know what to do. Production often comes to a standstill until the error has finally been pinpointed – and that can take hours. The causes are legion; in many cases it is all due to a single interrupted contact. Consequently, many manufacturers have long been hoping for a technology that will work without vulnerable power and data cables. The idea is basically feasible, using small devices that harvest energy from their surroundings and provide their own power supply rather like a solar calculator.

Experts speak of energy self-sufficient sensor-actuator systems. These high-tech components normally consist of a sensor, a processor and a radio module. They measure position, force or temperature and transmit the data instantaneously by radio. In this way, vital machine data reach the control center without using cables at all. Is the machine overheating? Is the drive shaft wearing out?

So far, however, there are hardly any off-the-shelf solutions with their own energy supply. Research scientists from the Fraunhofer Technology Development Group TEG in Stuttgart have now joined forces with industrial partners and universities in the EnAS project, sponsored by the Federal Ministry of Economics and Technology, to build a transportable demonstrator. This is a miniature conveyer system driven by compressed air that transports small components in an endless cycle.

The round workpieces are picked up by a vacuum gripper, transported a short way and set down on a small carrier, which conveys the parts back to the starting point. All steps of the process are monitored by sensors as usual. The special feature of the demonstrator is that the sensing elements have no need of an external power supply.

The machine uses photo diodes, for instance, to check whether the carrier has been correctly loaded – if so, the light from the diodes is obscured by the workpieces. Solar cells supply the energy for this workpiece detector. Another example are pressure sensors which monitor the work of the vacuum gripper. In this case, the power is supplied by piezoelectric flexural transducers. The piezoelectric elements contain ceramics that generate electricity on being deformed. This deformation happens when the vacuum pump is switched on and off. The electricity thus generated is sufficient to send an OK signal to the central control unit. The sensor thus draws its power from pressurized air that is present anyway.

Within the next two years, the various system components are expected to make their way into everyday industrial use.
Adapted from materials provided by Fraunhofer-Gesellschaft.

Rubber 'Snake' Could Help Wave Power Get A Bite Of The Energy Market

2008-07-04T10:31:00.000-07:00

ScienceDaily (July 3, 2008) — A device consisting of a giant rubber tube may hold the key to producing affordable electricity from the energy in sea waves. Invented in the UK, the 'Anaconda' is a totally innovative wave energy concept. Its ultra-simple design means it would be cheap to manufacture and maintain, enabling it to produce clean electricity at lower cost than other types of wave energy converter. Cost has been a key barrier to deployment of such converters to date.

Named after the snake of the same name because of its long thin shape, the Anaconda is closed at both ends and filled completely with water. It is designed to be anchored just below the sea's surface, with one end facing the oncoming waves.

A wave hitting the end squeezes it and causes a 'bulge wave'* to form inside the tube. As the bulge wave runs through the tube, the initial sea wave that caused it runs along the outside of the tube at the same speed, squeezing the tube more and more and causing the bulge wave to get bigger and bigger. The bulge wave then turns a turbine fitted at the far end of the device and the power produced is fed to shore via a cable.

Because it is made of rubber, the Anaconda is much lighter than other wave energy devices (which are primarily made of metal) and dispenses with the need for hydraulic rams, hinges and articulated joints. This reduces capital and maintenance costs and scope for breakdowns.

The Anaconda is, however, still at an early stage of development. The concept has only been proven at very small laboratory-scale, so important questions about its potential performance still need to be answered. Funded by the Engineering and Physical Sciences Research Council (EPSRC), and in collaboration with the Anaconda's inventors and with its developer (Checkmate SeaEnergy), engineers at the University of Southampton are now embarking on a programme of larger-scale laboratory experiments and novel mathematical studies designed to do just that.

Using tubes with diameters of 0.25 and 0.5 metres, the experiments will assess the Anaconda's behaviour in regular, irregular and extreme waves. Parameters measured will include internal pressures, changes in tube shape and the forces that mooring cables would be subjected to. As well as providing insights into the device's hydrodynamic behaviour, the data will form the basis of a mathematical model that can estimate exactly how much power a full-scale Anaconda would produce.

When built, each full-scale Anaconda device would be 200 metres long and 7 metres in diameter, and deployed in water depths of between 40 and 100 metres. Initial assessments indicate that the Anaconda would be rated at a power output of 1MW (roughly the electricity consumption of 2000 houses) and might be able to generate power at a cost of 6p per kWh or less. Although around twice as much as the cost of electricity generated from traditional coal-fired power stations, this compares very favourably with generation costs for other leading wave energy concepts.

"The Anaconda could make a valuable contribution to environmental protection by encouraging the use of wave power," says Professor John Chaplin, who is leading the EPSRC-funded project. "A one-third scale model of the Anaconda could be built next year for sea testing and we could see the first full-size device deployed off the UK coast in around five years' time."

The Anaconda was invented by Francis Farley (an experimental physicist) and Rod Rainey (of Atkins Oil and Gas). There may be advantages in making part of the tube inelastic, but this is still under assessment.

Wave-generated electricity is carbon-free and so can help the fight against global warming. Together with tidal energy, it is estimated that wave power could supply up to 20% of the UK's current electricity demand.

The two-year project 'The Hydrodynamics of a Distensible Wave Energy Converter' is receiving EPSRC funding of just over £430,000.

*A bulge wave is a wave of pressure produced when a fluid oscillates forwards and backwards inside a tube.
Adapted from materials provided by Engineering and Physical Sciences Research Council, via EurekAlert!, a service of AAAS.

New World Record For Efficiency For Solar Cells; Inexpensive To Manufacture

2008-05-23T03:18:00.000-07:00

ScienceDaily (May 17, 2008) — Physicist Bram Hoex and colleagues at Eindhoven University of Technology, together with the Fraunhofer Institute in Germany, have improved the efficiency of an important type of solar cell from 21.9 to 23.2 percent (a relative improvement of 6 per cent). This new world record is being presented on Wednesday May 14 at a major solar energy conference in San Diego.

The efficiency improvement is achieved by the use of an ultra-thin aluminum oxide layer at the front of the cell, and it brings a breakthrough in the use of solar energy a step closer.

An improvement of more than 1 per cent (in absolute terms) may at first glance appear modest, but it can enable solar cell manufacturers to greatly increase the performance of their products. This is because higher efficiency is a very effective way of reducing the cost price of solar energy. The costs of applying the thin layer of aluminum oxide are expected to be relatively low. This will mean a significant reduction in the cost of producing solar electricity.

Ultra-thin

Hoex was able to achieve the increase in efficiency by depositing an ultra-thin layer (approximately 30 nanometer) of aluminum oxide on the front of a crystalline silicon solar cell. This layer has an unprecedented high level of built-in negative charges, through which the -- normally significant -- energy losses at the surface are almost entirely eliminated. Of all sunlight falling on these cells, 23.2 per cent is now converted into electrical energy. This was formerly 21.9 per cent, which means a 6 per cent improvement in relative terms.

Dutch company OTB Solar

Hoex gained his PhD last week at the Applied Physics department of the TU/e with this research project. He was supported in the Plasma & Materials Processing (PMP) research group by professor Richard van de Sanden and associate professor Erwin Kessels. This group specializes in plasma deposition of extremely thin layers. The Dutch company OTB Solar has been a licensee of one of these processes since 2001, which it is using in its solar cell production lines. Numerous solar cell manufacturers around the world use equipment supplied by OTB Solar.

The ultra-thin aluminum oxide layer developed in the PMP group may lead to a technology innovation in the solar cell world. A number of major solar cell manufacturers have already shown interest.

Promising

Solar cells have for years looked like a highly promising way to partly solve the energy problem. The sun rises day after day, and solar cells can conveniently be installed on surfaces with no other useful purpose. Solar energy also offers opportunities for use in developing countries, many of which have high levels of sunshine. Within ten to fifteen years the price of electricity generated by solar cells is expected to be comparable to that of 'conventional' electricity from fossil fuels.

This technology breakthrough now brings the industrial application of this type of high-efficiency solar cell closer.

Part of Hoex's PhD research project was paid for by three Dutch ministries: Economic Affairs; Education, Culture and Science; and Housing, Spatial Planning and the Environment.
Adapted from materials provided by Eindhoven University of Technology.

Hybrid Vehicle Competition: Mississippi State Wins DOE And GM Challenge X 2008 Advanced Vehicle Competition

2008-05-23T03:08:00.000-07:00

ScienceDaily (May 21, 2008) — Mississippi State University in Starkville, Miss. is the first place winner of Challenge X, in which 17 university teams from across the U.S. and Canada competed to reengineer a General Motors (GM) Chevrolet Equinox Crossover SUV with advanced powertrain configurations. The winner of the competition achieved high fuel economy and low emissions, all while maintaining driver comfort and vehicle performance.

Department of Energy (DOE), GM and Natural Resources Canada also kicked off EcoCAR: The NeXt Challenge, a competition set to begin in the fall of 2008 that will challenge 17 university teams to re-engineer a Saturn VUE.

Over the past four years, 17 Challenge X university teams followed a real-world vehicle development process to produce advanced vehicle powertrain technologies that increased energy efficiency and reduced environmental impact. Those technologies were then integrated into GM vehicles and powered by a variety of alternative fuels including B20 biodiesel, E85 ethanol, reformulated gasoline, and hydrogen. GM, DOE, and the Canadian government congratulated students from 17 participating universities at a finish line ceremony this morning in Washington, D.C.

Students competed in 12 events over the eight day final competition, ranging from on-road emissions and drivability assessments to vehicle performance and consumer acceptability evaluations. The Mississippi State team designed a through-the-road parallel hybrid electric vehicle with all-wheel drive using a turbocharged direct-injection diesel engine fueled by B20 biodiesel. The vehicle demonstrated a 38 percent increase in energy efficiency over the production vehicle, a 1.6 second better quarter-mile acceleration performance, and a 44 percent reduction in well-to-wheel greenhouse gas emissions.

The second place vehicle, engineered by students at the University of Wisconsin – Madison, is a through-the-road parallel hybrid electric vehicle with a 1.9L diesel engine fueled by B20 biodiesel. Ohio State University was awarded third place for its power-split hybrid electric vehicle with a diesel engine fueled by B20 biodiesel.

In 2004, the first year of the program, the Challenge focused on vehicle simulation, modeling and subsystem development, and testing. In the second and third years, students integrated their advanced powertrains and subsystems into the Chevrolet Equinox. In the fourth year, students focused on consumer acceptability and over-the-road reliability and durability of their advanced propulsion systems with real-world evaluation outside of an official testing environment.

DOE’s Argonne National Laboratory (Argonne) provided competition management, team evaluation and technical and logistical support. The Greenhouse gas, Regulated Emissions, and Energy in Transportation model, developed at Argonne, was used to assess a well-to-wheel analysis of the greenhouse gas impacts of each technology approach the teams selected.

The 17 teams that participated in Challenge X are: Michigan Technological University—Houghton, Mich.; Mississippi State University—Starkville, Miss.; The Ohio State University— Columbus, Ohio; Pennsylvania State University—University Park, Pa.; Rose-Hulman Institute of Technology—Terre Haute, Ind.; San Diego State University—San Diego, Calif.; Texas Tech University—Lubbock, Texas; University of Akron—Akron, Ohio; University of California, Davis — Davis, Calif.; University of Michigan—Ann Arbor, Mich.; University of Tennessee—Knoxville, Tenn.; University of Texas at Austin—Austin, Texas; University of Tulsa—Tulsa, Okla.; University of Waterloo—Waterloo, Ontario Canada; University of Wisconsin-Madison — Madison, Wis.; Virginia Tech—Blacksburg, Va.; and West Virginia University— Morgantown, W.Va.

Students participating in the fall EcoCAR competition will design and build advanced propulsion solutions similar to the vehicle categories utilized by the California Air Resources Board (CARB) zero emissions vehicle (ZEV) regulations. In addition, they will incorporate lightweight materials into the vehicles, improve aerodynamics and utilize clean alternative fuels such as ethanol, biodiesel and hydrogen. Funding for EcoCar in FY 2009 and beyond is subject to annual appropriations.

The following teams have been selected to compete in the EcoCAR competition: Embry-Riddle Aeronautical University—Daytona Beach, Fla.; Georgia Tech —Atlanta, Ga.; Howard University —Washington, D.C.; Michigan Technological University — Houghton, Mich.; Mississippi State University — Starkville, Miss.; Missouri University of Science and Technology — Rolla, Miss.; North Carolina State University — Raleigh, N.C.; Ohio State University — Columbus, Ohio; Ontario Institute of Technology — Oshawa, Ontario, Canada; Pennsylvania State University — University Park, Pa.; Rose-Hulman Institute of Technology — Terre Haute, Ind.; Texas Tech University — Lubbock, Texas; University of Victoria Victoria, British Columbia, Canada; University of Waterloo — Waterloo, Ontario, Canada; University of Wisconsin, Madison —Madison, Wis.; Virginia Tech —Blacksburg, Va.; and, West Virginia University —Morgantown, W. Va..
Adapted from materials provided by US Department of Energy.

Beating The Codebreakers With Quantum Cryptography

2008-04-28T11:43:00.001-07:00

ScienceDaily (Apr. 28, 2008) — Quantum cryptography may be essentially solved, but getting the funky physics to work on disciplined computer networks is a whole new headache.

Cryptography is an arms race, but the finish line may be fast approaching. Up to now, each time the codemakers made a better mousetrap, codebreakers breed a better mouse. But quantum cryptography theoretically could outpace the codebreakers and win the race. Forever.

Already the current state of the art in classical encryption, 128-bit RSA, can be cracked with enough raw, brute force computing power available to organisations like the US National Security Agency. And the advent of quantum computing will make it even simpler. The gold standard for secret communication will be truly dead.

Quantum cryptography solves the problem, and it will overcome the remaining stumbling block, the distribution of the code key to the right person, by using quantum key distribution (QKD).

Modern cryptography relies on the use of digital ‘keys’ to encrypt data before sending it over a network, and to decrypt it at the other end. The receiver must have a version of the key code used by the sender so as to be able to decrypt and access the data.

QKD offers a theoretically uncrackable code, one that is easily distributed and works in a transparent manner. Even better, the nature of quantum mechanics means that if any eavesdropper – called Eve in the argot of cryptographers – tries to snoop on a message the sender and receiver will both know.

That ability is due to the use of the Heisenberg Uncertainty Principle, which sits at the heart of quantum mechanics. The principle rests on the theory that the act of measuring a quantum state changes that state. It is like children with a guilty secret. As soon as you look at them their faces morph plausibly into ‘Who, me?’

The practical upshot for cryptography is that the sender and receiver can verify the security of the transmission. They will know if the state of the quanta has changed, whether the key has been read en route. If so, they can abandon the key they are using and generate a new one.

QKD made its real-world debut in the canton of Geneva for use in the electronic voting system used in the Swiss general election last year. The system guaranteed that the poll was secure. But, more importantly perhaps, it also ensured that no vote was lost in transmission, because the uncertainly principle established there was no change to the transmitted data.

The end of the beginning

The canton election was a demonstration of the work done by researchers for the SECOQC project, an EU-funded effort to develop an international network for secure communication based on QKD.

The test of the technology demonstrated that QKD worked for point-to-point communications between two parties. But the demonstration was just the beginning of the SECOQC’s overall goal.

“We want to establish a network wide quantum encryption, because it will mean it works over much longer distances,” explains Christian Monyk, co-ordinator of the SECOQC project and head of the quantum-technologies unit at the Austrian Research Centres. “Network quantum encryption and QKD mean that many parties can communicate securely, not just two. Finally, it also means quantum encryption could be deployed on a very large scale, for the insurance and banking sectors, for example.”

Moving the system from point-to-point communications to a network is an order of magnitude more difficult.

“The quantum science for cryptography and key distribution is essentially solved, and it is a great result,” Monyk says. “But getting that system to work across a network is much more difficult. You have to deal with different protocols and network architectures, develop new nodes and new interfaces with the quantum devices to get it to a large-scale, long distance, real-world application.”

Working at a distance

Getting the system to work over long distances is also a challenge because QKD requires hi-fidelity data transmission over high-quality physical networks like non-zero dispersion shifted fibre optics.

“It was not one big problem, it was many, many small computing science and engineering problems,” says Monyk. “We had to work with a large number of technologies. And we have to certify it to experts.”

But SECOQC’s researchers believe they have solved the network issue. The researchers are currently putting the final touches to a demonstration of the technology to be held this October in Vienna, Austria. Industry has shown great interest in the technology. Still the technology is not quite ready for prime time.

“From a technical point of view, the technology will be ready in one or two years,” says Monyk.

And that means that the race will be won, finally, by the codemakers.

Adapted from materials provided by ICT Results.

Aeronautics Engineers Design Silent, Eco-friendly Plane

2008-04-28T11:38:00.001-07:00

ScienceDaily (Nov. 7, 2006) — MIT and Cambridge University researchers unveiled the conceptual design for a silent, environmentally friendly passenger plane at a press conference Monday, Nov. 6, at the Royal Aeronautical Society in London.

"Public concern about noise is a major constraint on expansion of aircraft operations. The 'silent aircraft' can help address this concern and thus aid in meeting the increasing passenger demand for air transport," said Edward M. Greitzer, the H.N. Slater Professor of Aeronautics and Astronautics at MIT.

Greitzer and Professor Ann P. Dowling of Cambridge University are the lead principal investigators on the Silent Aircraft Initiative. This collaboration of 40 researchers from MIT and Cambridge, plus many others from more than 30 companies, was launched three years ago "to develop a conceptual design for an aircraft whose noise was almost imperceptible outside the perimeter of an airfield in an urban environment."

While originally conceived to make a huge reduction in airplane noise, the team's ultimate design also has the potential to be more fuel-efficient. In a typical flight, the proposed plane, which is designed to carry 215 passengers, is predicted to achieve 124 passenger-miles per gallon, almost 25 percent more than current aircraft, according to Greitzer. (For a down-to-earth comparison, the Toyota Prius hybrid car carrying two passengers achieves 120 passenger-miles per gallon.)

The project aims to develop aircraft by 2030.

The conceptual design addresses both the engines and the structure, or airframe, of a plane. Half of the noise from a landing plane comes from the airframe.

Other key features of the design include:

* An overall shape that integrates body and wings into a "single" flying wing. As a result, both the body and wings provide lift, allowing a slower approach and takeoff, which would reduce noise. The shape also improves fuel efficiency.
* The elimination of the flaps, or hinged rear sections on each wing. These are a major source of airframe noise when a plane is taking off and landing.
* Engines embedded in the aircraft with air intakes on top of the plane rather than underneath each wing. This screens much of the noise from the ground.
* A variable-size jet nozzle that allows slower jet propulsion during takeoff and landing but efficient cruising at higher speeds.

What will it take to turn the design into a plane by 2030?

"One major technical challenge is the integration of the propulsion system with the aircraft," Greitzer said. "The propulsion system, with engines embedded in the fuselage, is different than for traditional civil aircraft, in which the engines are located in nacelles below the wing. This presents a different set of issues to the designer."

Zoltan S. Spakovszky, C. S. Draper Associate Professor in MIT's Department of Aeronautics and Astronautics, also cited the integration of the propulsion system as a key challenge. Spakovszky and James I. Hileman, a research engineer in the department, are the chief engineers, or day-to-day managers, for the project.

He explained that in today's airplanes, with engines hanging below the wings, air flows unimpeded into the engine. In the new design, however, air traveling into the air intakes on top of the plane will behave differently. This is because the air particles flowing close to the plane's body experience friction. As a result, "the particles flow at a lower velocity near the surface of the plane than in the free (air) stream," Spakovszky said. The new engine must be designed to operate in these strongly nonuniform airflows.

A second important technical challenge involves the craft's unconventional airframe, Spakovszky said. "The structural integrity of a pressure vessel allowing this single wing-like shape needs to be ensured and poses a major challenge."

Greitzer emphasized that the collaboration between MIT, Cambridge University and their industrial partners was key to the end result.

"Collaboration and teaming occurred in essentially all aspects of the project. The Silent Aircraft Initiative has been very much an enterprise in which the whole is greater than the sum of the separate parts," he said.

Spakovszky referred to the overall team effort as the best part of the project. "Technical expectations were taken for granted, but working well across the Atlantic was not a given," he said. "It was a very, very neat experience."

The Silent Aircraft Initiative is funded by the Cambridge-MIT Institute, which has supported a wide range of research and educational collaborations between the two universities. The Knowledge Integration Community (or KIC) that created the conceptual design included academic staff and students from both institutions and participants from a wide range of industrial collaborators including Boeing and Rolls Royce.

Adapted from materials provided by Massachusetts Institute Of Technology.

Next-generation Sensors May Help Avert Airline Disasters

2008-04-28T11:29:00.001-07:00

ScienceDaily (Mar. 28, 2008) — Everyone on board an Scandinavian Airline System (SAS) plane died when it collided with a light aircraft and exploded in a luggage hanger in Milan in 2001. The smaller plane had taxied wrongly and ended up on the runway where the SAS aircraft was taking off.

The following year, two planes collided in mid-air over Überlingen in the south of Germany on the edge of Lake Constance. One was a Russian passenger flight from Moscow to Barcelona, while the other was a cargo plane heading for Belgium from the Persian Gulf. Seventy-one persons died.

Safety need to be improved

As air transport grows, take-offs become more tightly spaced and more and more planes are circling airports as they wait for permission to land, the potential for disasters increases.

Last year alone, international air traffic grew by 5.9 percent. Parallel to this increase, the minimum distance between aircraft in the air in European airspace has decreased. The minimum vertical distance between aircraft has been halved from 600 metres to 300 for planes flying above 29000 feet. The idea has been to increase airspace capacity by 20 percent. Routes are shortened, and airlines expect to save the huge sum of NOK 30 billion a year in fuel costs alone.

But what above safety up there? In the wake of a number of disasters in the air in 2001 and 2002, the EU took up the problem and resolved that certain aspects of the industry should be studied in detail and evaluated in terms of safety. Several projects were launched under its 6th Framework Programme. One of these was the HASTEC project, which was to develop the next generation of pressure sensors for better aircraft altitude measurement.

Next-generation sensors

“There is a need for aircraft sensors that are more accurate than current models, which are large and reliable, but expensive systems,” says Sigurd Moe of SINTEF ICT. “Among other things, they need to be more stable throughout their life-cycle. The problem with current sensors is that they need to be checked and calibrated regularly, and this is an expensive process since the aircraft needs to be grounded.

Challenges

The problem is that mechanical tensions may develop in the connection with the sensor package itself. The scientists therefore had to produce a silicon based sensor structure in which such tensions would not transmit/propogate into the chip itself. The solution was a spiral silicon element in which the pressure-sensitive part was not affected even if the mounting stretches and drags the element.

SINTEF produces silicon wafers with hundreds of chips on each wafer, several of which are laid on top of each other and glued together before being sawn into chips. Individual chips are then selected and integrated into a sensor package that has been developed by Memscap. The company produces, assembles and tests the sensor package itself.

The first prototype has now been delivered to Memscap by the scientists for further testing and mounting. During the first six months of 2008 these new-technology sensors will be flight tested.

Adapted from materials provided by SINTEF, via AlphaGalileo.

Next Step In Robot Development Is Child's Play

2008-04-28T11:25:00.000-07:00

ScienceDaily (Apr. 26, 2008) — Teaching robots to understand enough about the real world to allow them act independently has proved to be much more difficult than first thought.

The team behind the iCub robot believes it, like children, will learn best from its own experiences.

The technologies developed on the iCub platform – such as grasping, locomotion, interaction, and even language-action association – are of great relevance to further advances in the field of industrial service robotics.

The EU-funded RobotCub project, which designed the iCub, will send one each to six European research labs. Each of the labs proposed winning projects to help train the robots to learn about their surroundings – just as a child would.

The six projects include one from Imperial College London that will explore how ‘mirror neurons’ found in the human brain can be translated into a digital application. ‘Mirror neurons’, discovered in the early 1990s, trigger memories of previous experiences when humans are trying to understand the physical actions of others. A separate team at UPF Barcelona will also work on iCub’s ‘cognitive architecture’.

At the same time, a team headquartered at UPMC in Paris will explore the dynamics needed to achieve full body control for iCub. Meanwhile, researchers at TUM Munich will work on the development of iCub’s manipulation skills. A project team from the University of Lyons will explore internal simulation techniques – something our brains do when planning actions or trying to understand the actions of others.

Over in Turkey, a team based at METU in Ankara will focus almost exclusively on language acquisition and the iCub’s ability to link objects with verbal utterances.

“The six winners had to show they could really use and maintain the robot, and secondly the project had to exploit the capabilities of the robot,” says Giorgio Metta. “Looking at the proposals from the winners, it was clear that if we gave them a robot we would get something in return.”

The iCub robots are about the size of three-year-old children, with highly dexterous hands and fully articulated heads and eyes. They have hearing and touch capabilities and are designed to be able to crawl on all fours and to sit up.

Humans develop their abilities to understand and interact with the world around them through their experiences. As small children, we learn by doing and we understand the actions of others by comparing their actions to our previous experience.

The developers of iCub want to develop their robots’ cognitive capabilities by mimicking that process. Researchers from the EU-funded Robotcub project designed the iCub’s hardware and software using a modular system. The design increases the efficiency of the robot, and also allows researcher to more easily update individual components. The modular design also allows large numbers of researchers to work independently on separate aspects of the robot.

iCub’s software coding, along with technical drawings, are free to anyone who wishes to download and use them.

“We really like the idea of being open as it is a way to build a community of many people working towards a common objective,” says Giorgio Metta, one of the developers of iCub. “We need a critical mass working on these types of problems. If you get 50 researchers, they can really layer knowledge and build a more complex system. Joining forces really makes economic sense for the European Commission that is funding these projects and it makes scientific sense.”

Built-in learning skills

While the iCub’s hardware and mechanical parts are not expected to change much over the next 18 months, researchers expect to develop the software further. To enable iCub to learn by doing, the Robotcub research team is trying to pre-fit it with certain innate skills.

These include the ability to track objects visually or by the sounds – with some element of prediction of where the tracked object will move to next. iCub should also be able to navigate based on landmarks and a sense of its own position.

But the first and key skill iCub needs for learning by doing is an ability to reach towards a fixed point. By October this year, the iCub developers plan to develop the robot so it is able to analyse the information it receives via its vision and feel ‘senses’. The robot will then be able to use this information to perform at least some crude grasping behaviour – reaching outwards and closing its fingers around an object.

“Grasping is the first step in developing cognition as it is required to learn how to use tools and to understand that if you interact with an object it has consequences,” says Giorgio Metta. “From there the robot can develop more complex behaviours as it learns that particular objects are best manipulated in certain ways.”

Once the assembly of the six robots for the research projects is completed, the developers plan to build more iCubs, creating between 15 and 20 in use around Europe.

Adapted from materials provided by ICT Results.

Data Transfer In The Brain: Newfound Mechanism Enables Reliable Transmission Of Neuronal Information

2008-04-22T18:50:00.000-07:00

ScienceDaily (Apr. 22, 2008) — The receptors of neurotransmitters move very rapidly. This mobility plays an essential, and hitherto unsuspected, role in the passage of nerve impulses from one neuron to another, thus controlling the reliability of data transfer. This has recently been demonstrated by scientists in the "Physiologie cellulaire de la synapse" Laboratory (CNRS/Université Bordeaux 2) coordinated by Daniel Choquet, senior researcher at CNRS.

By enabling a clearer understanding of the mechanisms involved in neuronal transmissions, this work opens the way to new therapeutic targets for the neurological and psychiatric disorders that depend on poor neuronal communication (Parkinson's disease, Alzheimer's disease, OCD, etc.). Fruit of a collaboration with physicists in the Centre de physique moléculaire optique et hertzienne (CPMOH, CNRS/Université Bordeaux 1) and German and American research teams(1), these findings were published on April 11, 2008 in Science.

The processing of information by the brain is mainly based on the coding of data by variations in the frequency of neuronal activity. "Good" communication thus implies the reliable transmission of this "code" by the connections between neurons, or synapses. Under normal circumstances, this junction comprises a pre-synaptic element from which the information arises, and a post-synaptic element which receives it.

It is at this point that neuronal communication occurs. Once the pre-synaptic neuron has been stimulated by an electrical signal with a precise frequency, it releases chemical messengers into the synapse: neurotransmitters. And the response is rapid! These neurotransmitters bind to specific receptors, thus provoking a change to the electrical activity of the post-synaptic neuron and hence the birth of a new signal.

The mobility of receptors controls the reliability of neuronal transmission. Working at the interface between physics and biology, the teams in Bordeaux led by Choquet, CNRS senior researcher in the "Physiologie cellulaire de la synapse"(2) laboratory, working in close collaboration with the group led by

Brahim Lounis at the Centre de physique moléculaire optique et hertzienne(2) have been studying synaptic transmission and, more particularly, the role of certain receptors of glutamate, a neurotransmitter present in 80% of neurons in the brain.

Focusing on the dynamics of these receptors, the researchers have revealed that a minor modification to their mobility has a major impact on high frequency synaptic transmission, i.e. at frequencies between 50 and 100 Hz (those which intervene during memorization, learning or sensory stimulation processes). More specifically, they have established that this mobility enables the replacement in a few milliseconds of desensitized receptors by "naïve" receptors in the synapse. This phenomenon reduces synaptic depression(3) and allows the neurons to transmit the information at a higher frequency. By contrast, if the receptors are immobilized, this depression is notably enhanced, preventing transmission of the nerve impulse in the synapses above around ten Hertz.

More profoundly, the scientists have demonstrated that prolonged series of high frequency stimulations, which induce an increase in calcium levels in the synapses, cause the immobilization of receptors. They have also proved that these series of stimulations diminish the ability of neurons to transmit an activity at high frequency. Receptor mobility is thus correlated with the frequency of synaptic transmission and consequently, the reliability of this transmission.

A real advance for research

When the brain is functioning under normal conditions, we can suppose that the immobilization of receptors following a series of high frequency stimulations constitutes a safety mechanism. It will prevent subsequent series from overexciting the post-synaptic neuron. A reliable transmission of information between two neurons is obviously crucial to satisfactory functioning of the brain.

These results, of prime importance, suggest that some dysfunctions of neuronal transmission are due to a defect in receptor stabilization. However, high frequency electrical stimulation of certain regions of the brain is used to treat Parkinson's disease or obsessive-compulsive disorders (OCD). Its mechanism of action, still poorly understood, may therefore involve receptor mobility. This work has thus made it possible to identify new therapeutic targets and could augur well for potential drugs to treat neurological and psychiatric disorders which often result from poor communication between neurons.

Notes

1. Teams at the Leibniz Institute, Magdeburg and Johns Hopkins University School of Medicine, Baltimore, USA.
2. CNRS/Université Bordeaux 2.
3. CPMOH, CNRS/Université Bordeaux 1.
4. When a pre-synaptic neuron is stimulated at very frequent intervals (high frequencies of around 50-100 Hertz), the post-synaptic response generally diminishes over time: this is called synaptic depression. The higher the stimulation frequency, the more this depression increases.

Journal reference: Surface Mobility of Post-synaptic AMPARs Tunes Synaptic Transmission. Martin Heine, Laurent Groc, Renato Frischknecht, Jean-Claude Béïque, Brahim Lounis, Gavin Rumbaugh, Richard L. Huganir, Laurent Cognet and Daniel Choquet. Science. 11 April 2008.

Adapted from materials provided by CNRS.

Breastfeeding While Taking Seizure Medicine Does Not Appear To Harm Children, Study Suggests

2008-04-22T18:45:00.000-07:00

ScienceDaily (Apr. 22, 2008) — A first of its kind study finds breastfeeding while taking certain seizure medications does not appear to harm a child's cognitive development.
"Our early findings show breastfeeding during anti-epilepsy drug treatment doesn't appear to have a negative impact on a child's cognitive abilities," said study author Kimford Meador, MD, with the University of Florida at Gainesville, and Fellow of the American Academy of Neurology. "However, more research is needed to confirm our findings and women should use caution due to the limitations of our study."

Researchers tested the cognitive development of 187 two-year-old children whose mothers were taking the epilepsy drugs lamotrigine, carbamazepine, phenytoin, or valproate. Forty-one percent of the children were breastfed.

The study found breastfed children had higher cognitive test scores than those children who were not breastfed, and this trend was consistent for each anti-epilepsy drug. The children who were breastfed received an average test score of 98.1 compared to a score of 89.5 for the children not breastfed. However, the results were not significant after adjusting for the mother's IQ. Thus, it appears that the higher scores in children who were breastfed is due to the fact that their mothers had higher IQs.

Meador says animal studies have shown that some anti-epilepsy drugs, but not all, can cause cells to die in immature brains, but this effect can be blocked by the protective effects of beta estradiol, which is the mother's sex hormone. "Since the potential protective effects of beta estradiol in utero are absent after birth, concern was raised that breastfeeding by women taking anti-epilepsy drugs may increase the risk of anti-epilepsy drug-induced cell death and result in reduced cognitive outcomes in children."

Meador says additional research on the effects of breastfeeding should be extended to other anti-epilepsy drugs and mothers who use more than one anti-epilepsy medication.

The study is part of an ongoing study of the long-term effects of in utero anti-epilepsy drug exposure on children's cognition. Women with epilepsy who were taking anti-epilepsy drugs were enrolled in the study during pregnancy. Ultimately, the study will examine the effects of in utero anti-epilepsy drug exposure on children at six years old.

This research was presented at the upcoming American Academy of Neurology 60th Anniversary Annual Meeting in Chicago, April 17, 2008.

Adapted from materials provided by American Academy of Neurology.

Chemotherapy's Damage To The Brain Detailed

2008-04-22T18:35:00.000-07:00

ScienceDaily (Apr. 22, 2008) — A commonly used chemotherapy drug causes healthy brain cells to die off long after treatment has ended and may be one of the underlying biological causes of the cognitive side effects -- or "chemo brain" -- that many cancer patients experience. That is the conclusion of a study published today in the Journal of Biology.

A team of researchers at the University of Rochester Medical Center (URMC) and Harvard Medical School have linked the widely used chemotherapy drug 5-fluorouracil (5-FU) to a progressing collapse of populations of stem cells and their progeny in the central nervous system.

"This study is the first model of a delayed degeneration syndrome that involves a global disruption of the myelin-forming cells that are essential for normal neuronal function," said Mark Noble, Ph.D., director of the University of Rochester Stem Cell and Regenerative Medicine Institute and senior author of the study. "Because of our growing knowledge of stem cells and their biology, we can now begin to understand and define the molecular mechanisms behind the cognitive difficulties that linger and worsen in a significant number of cancer patients."

Cancer patients have long complained of neurological side effects such as short-term memory loss and, in extreme cases, seizures, vision loss, and even dementia. Until very recently, these cognitive side effects were often dismissed as the byproduct of fatigue, depression, and anxiety related to cancer diagnosis and treatment. Now a growing body of evidence has documented the scope of these conditions, collectively referred to as chemo brain. And while it is increasingly acknowledged by the scientific community that many chemotherapy agents may have a negative impact on brain function in a subset of cancer patients, the precise mechanisms that underlie this dysfunction have not been identified.

Virtually all cancer survivors experience short-term memory loss and difficulty concentrating during and shortly after treatment. A study two years ago by researchers with the James P. Wilmot Cancer Center at the University of Rochester showed that upwards of 82% of breast cancer patients reported that they suffer from some form of cognitive impairment.

While these effects tend to wear off over time, a subset of patients, particularly those who have been administered high doses of chemotherapy, begin to experience these cognitive side effects months or longer after treatment has ceased and the drugs have long since departed their systems. For example, a recent study estimates that somewhere between 15 and 20 percent of the nation's 2.4 million female breast cancer survivors have lingering cognitive problems years after treatment. Another study showed that 50 percent of women had not recovered their previous level of cognitive function one year after treatment.

Two years ago, Noble and his team showed that three common chemotherapy drugs used to treat a wide range of cancers were more toxic to healthy brain cells than the cancer cells they were intended to treat. While these experiments were among the first to establish a biological basis for the acute onset of chemo brain, they did not explain the lingering impact that many patients experience.

The scientists conducted a similar series of experiments in which they exposed both individual cell populations and mice to doses of 5-fluorouracil (5-FU) in amounts comparable to those used in cancer patients. 5-FU is among a class of drugs called antimetabolites that block cell division and has been used in cancer treatment for more than 40 years. The drug, which is often administered in a "cocktail" with other chemotherapy drugs, is currently used to treat breast, ovarian, stomach, colon, pancreatic and other forms of cancer.

The researchers discovered that months after exposure, specific populations of cells in the central nervous -- oligodendrocytes and dividing precursor cells from which they are generated -- underwent such extensive damage that, after 6 months, these cells had all but disappeared in the mice.

Oligodendrocytes play an important role in the central nervous system and are responsible for producing myelin, the fatty substance that, like insulation on electrical wires, coats nerve cells and enables signals between cells to be transmitted rapidly and efficiently. The myelin membranes are constantly being turned over, and without a healthy population of oligodendrocytes, the membranes cannot be renewed and eventually break down, resulting in a disruption of normal impulse transmission between nerve cells.

These findings parallel observations in studies of cancer survivors with cognitive difficulties. MRI scans of these patients' brains revealed a condition similar to leukoencephalopathy. This demyelination -- or the loss of white matter -- can be associated with multiple neurological problems.

"It is clear that, in some patients, chemotherapy appears to trigger a degenerative condition in the central nervous system," said Noble. "Because these treatments will clearly remain the standard of care for many years to come, it is critical that we understand their precise impact on the central nervous system, and then use this knowledge as the basis for discovering means of preventing such side effects."

Noble points out that not all cancer patients experience these cognitive difficulties, and determining why some patients are more vulnerable may be an important step in developing new ways to prevent these side effects. Because of this study, researchers now have a model which, for the first time, allows scientists to begin to examine this condition in a systematic manner.
###

Other investigators participating in the study include Ruolan Han, Ph.D., Yin M. Yang, M.D., Anne Luebke, Ph.D., Margot Mayer-Proschel, Ph.D., all with URMC, and Joerg Dietrich, M.D., Ph.D., formerly with URMC and now with Harvard Medical School. The study was funded by the National Institutes of Neurological Disorders and Stroke, the Komen Foundation for the Cure, and the Wilmot Cancer Center.

Adapted from materials provided by University of Rochester Medical Center.

Contact Lenses With Circuits, Lights A Possible Platform For Superhuman Vision

2008-04-22T18:20:00.000-07:00

ScienceDaily (Jan. 17, 2008) — Movie characters from the Terminator to the Bionic Woman use bionic eyes to zoom in on far-off scenes, have useful facts pop into their field of view, or create virtual crosshairs. Off the screen, virtual displays have been proposed for more practical purposes -- visual aids to help vision-impaired people, holographic driving control panels and even as a way to surf the Web on the go.

The device to make this happen may be familiar. Engineers at the University of Washington have for the first time used manufacturing techniques at microscopic scales to combine a flexible, biologically safe contact lens with an imprinted electronic circuit and lights.

"Looking through a completed lens, you would see what the display is generating superimposed on the world outside," said Babak Parviz, a UW assistant professor of electrical engineering. "This is a very small step toward that goal, but I think it's extremely promising." The results were presented today at the Institute of Electrical and Electronics Engineers' international conference on Micro Electro Mechanical Systems by Harvey Ho, a former graduate student of Parviz's now working at Sandia National Laboratories in Livermore, Calif. Other co-authors are Ehsan Saeedi and Samuel Kim in the UW's electrical engineering department and Tueng Shen in the UW Medical Center's ophthalmology department.

There are many possible uses for virtual displays. Drivers or pilots could see a vehicle's speed projected onto the windshield. Video-game companies could use the contact lenses to completely immerse players in a virtual world without restricting their range of motion. And for communications, people on the go could surf the Internet on a midair virtual display screen that only they would be able to see.

"People may find all sorts of applications for it that we have not thought about. Our goal is to demonstrate the basic technology and make sure it works and that it's safe," said Parviz, who heads a multi-disciplinary UW group that is developing electronics for contact lenses.

The prototype device contains an electric circuit as well as red light-emitting diodes for a display, though it does not yet light up. The lenses were tested on rabbits for up to 20 minutes and the animals showed no adverse effects.

Ideally, installing or removing the bionic eye would be as easy as popping a contact lens in or out, and once installed the wearer would barely know the gadget was there, Parviz said.

Building the lenses was a challenge because materials that are safe for use in the body, such as the flexible organic materials used in contact lenses, are delicate. Manufacturing electrical circuits, however, involves inorganic materials, scorching temperatures and toxic chemicals. Researchers built the circuits from layers of metal only a few nanometers thick, about one thousandth the width of a human hair, and constructed light-emitting diodes one third of a millimeter across.

They then sprinkled the grayish powder of electrical components onto a sheet of flexible plastic. The shape of each tiny component dictates which piece it can attach to, a microfabrication technique known as self-assembly. Capillary forces -- the same type of forces that make water move up a plant's roots, and that cause the edge of a glass of water to curve upward -- pull the pieces into position.

The prototype contact lens does not correct the wearer's vision, but the technique could be used on a corrective lens, Parviz said. And all the gadgetry won't obstruct a person's view.

"There is a large area outside of the transparent part of the eye that we can use for placing instrumentation," Parviz said. Future improvements will add wireless communication to and from the lens. The researchers hope to power the whole system using a combination of radio-frequency power and solar cells placed on the lens, Parviz said.

A full-fledged display won't be available for a while, but a version that has a basic display with just a few pixels could be operational "fairly quickly," according to Parviz.

The research was funded by the National Science Foundation and a Technology Gap Innovation Fund from the University of Washington.

Adapted from materials provided by University of Washington.

3-D Images -- Cordless And Any Time

2008-04-21T22:16:00.000-07:00

ScienceDaily (Apr. 21, 2008) — Securing evidence at the scene of a crime, measuring faces for medical applications, taking samples during production – three-dimensional images are in demand everywhere. A handy cordless device now en-ables such images to be prepared rapidly anywhere.

The car tires have left deep tracks in the muddy forest floor at the scene of the crime. The forensic experts make a plaster cast of the print, so that it can later be compared with the tire profiles of suspects’ cars. There will soon be an easier way of doing it: The police officers will only need to pick up a 3-D sensor, press a button as on a camera, and a few seconds later they will see a three-dimensional image of the tire track on their laptop computer.

The sensor is no larger than a shoebox and weighs only about a kilogram – which means it is easy to handle even on outdoor missions such as in the forest. No cable drums are needed: The sensor radios the data to the computer via WLAN, and draws its power from batteries.

The sensor was developed at the Fraunhofer Institute for Applied Optics and Precision Engineering IOF in Jena. “It consists of two cameras with a projector in the center,” says IOF head of department Dr. Gunther Notni. “The two cameras provide a three-dimensional view, rather like two eyes. The projector casts a pattern of stripes on the objects. The geometry of the measured object can be deduced from the deformation of the stripes.”

This type of stripe projection is already an established method. What is new about the measuring device named ‘Kolibri CORDLESS’ are its measuring speed, size, weight, and cordless operation. For comparison, conventional devices of this type weigh about four or five times as much and are more than twice the size, or roughly 50 centimeters long. “The reason it can be so much smaller is because of the projector, which produces light with light-emitting diodes instead of the usual halogen lamps,” says Notni. This poses an additional challenge, as the LEDs shine in all directions. To ensure that the image is nevertheless bright enough, the light has to be collected with special micro-optics in such a way that it impacts on the lens.

There are multiple applications: “Patients who snore often need a breathing mask when they sleep. To ensure that the mask is not too tight, it has to be specially made for each patient. Our system enables the doctor to scan the patient’s face in just a few seconds and have the breathing mask made to match these data,” says the researcher. Notni believes that the most important application is for quality assurance in production processes. The portable device also makes it possible to measure installed components and zones that are difficult to access, such as the position of foot pedals inside a car. The researchers will be presenting their development at the Control trade fair in Stuttgart on April 21 through 25 (Hall 1, Stand 1520).

Adapted from materials provided by Fraunhofer-Gesellschaft.

Micro Sensor And Micro Fridge Make Cool Pair

2008-04-21T21:54:00.000-07:00

ScienceDaily (Apr. 17, 2008) — Researchers at the National Institute of Standards and Technology (NIST) have combined two tiny but powerful NIST inventions on a single microchip, a cryogenic sensor and a microrefrigerator. The combination offers the possibility of cheaper, simpler and faster precision analysis of materials such as semiconductors and stardust.

As described in an upcoming issue of Applied Physics Letters,* the NIST team combined a transition-edge sensor (TES), a superconducting thin film that identifies X-ray signatures far more precisely than any other device, with a solid-state refrigerator based on a sandwich of a normal metal, an insulator and a superconductor. The combo chip, a square about a quarter inch on a side, achieved the first cooling of a fully functional detector (or any useful device) with a microrefrigerator.

The paper also reports the greatest temperature reduction in a separate object by microrefrigerators: a temperature drop of 110 millikelvins (mK), or about a tenth of a degree Celsius.

TES sensors are most sensitive at about 100 mK (a tenth of a degree Celsius above absolute zero). However, these ultralow temperatures are usually reached only by bulky, complex refrigerators. Because the NIST chip can provide some of its own cooling, it can be combined easily with a much simpler refrigerator that starts at room temperature and cools down to about 300 mK, says lead scientist Joel Ullom. In this setup, the chip would provide the second stage of cooling from 300mK down to the operating temperature (100 mK).

One promising application is cheaper, simpler semiconductor defect analysis using X-rays. A small company is already commercializing an earlier version of TES technology for this purpose. In another application, astronomical telescopes are increasingly using TES arrays to take pictures of the early universe at millimeter wavelengths. Use of the NIST chips would lower the temperature and increase the speed at which these images could be made, Ullom says.

The work was supported in part by the National Aeronautics and Space Administration.

* N.A. Miller, G.C. O'Neil, J.A. Beall, G.C. Hilton, K.D. Irwin, D.R. Schmidt, L.R. Vale and J.N. Ullom. High resolution X-ray transition-edge sensor cooled by tunnel junction refrigerators. Forthcoming in Applied Physics Letters.

Adapted from materials provided by National Institute of Standards and Technology.

Innovative Composite Opens Terahertz Frequencies To Many Applications

2008-04-19T21:47:00.000-07:00

ScienceDaily (Apr. 16, 2008) — A frequency-agile metamaterial that for the first time can be tuned over a range of frequencies in the so-called "terahertz gap" has been engineered by a team of researchers from Boston College, Los Alamos National Laboratory and Boston University.

The team incorporated semiconducting materials in critical regions of tiny elements -- in this case metallic split-ring resonators -- that interact with light in order to tune metamaterials beyond their fixed point on the electromagnetic spectrum, an advance that opens these novel devices to a broader array of uses, according to findings published in the online version of the journal Nature Photonics.

"Metamaterials no longer need to be constructed only out of metallic components," said Boston College Physicist Willie J. Padilla, the project leader. "What we've shown is that one can take the exotic properties of metamaterials and combine them with the unique prosperities of natural materials to form a hybrid that yields superior performance."

Padilla and BC graduate student David Shrekenhamer, along with Hou-Tong Chen, John F. O'Hara, Abul K Azad and Antoinette J. Tayler of Los Alamos National Laboratory, and Boston University's Richard D. Averitt formed a single layer of metamaterial and semiconductor that allowed the team to tune terahertz resonance across a range of frequencies in the far-infrared spectrum.

The team's first-generation device achieved 20 percent tuning of the terahertz resonance to lower frequencies -- those in the far-infrared region --addressing the critical issue of narrow band response typical of all metamaterial designs to date.

Constructed on the micron-scale, metamaterials are composites that use unique metallic contours in order to produce responses to light waves, giving each metamaterial its own unique properties beyond the elements of the actual materials in use.

Within the past decade, researchers have sought ways to significantly expand the range of material responses to waves of electromagnetic radiation -- classified by increasing frequency as radio waves, microwaves, terahertz radiation, infrared radiation, visible light, ultraviolet radiation, X-rays and gamma rays. Numerous novel effects have been demonstrated that defy accepted principles.

"Metamaterials demonstrated negative refractive index and up until that point the commonly held belief was that only a positive index was possible," said Padilla. "Metamaterials gave us access to new regimes of electromagnetic response that you could not get from normal materials."

Prior research has shown that because they rely on light-driven resonance, metamaterials experience frequency dispersion and narrow bandwidth operation where the centre frequency is fixed based on the geometry and dimensions of the elements comprising the metamaterial composite. The team believes that the creation of a material that addresses the narrow bandwidth limitations can advance the use of metamaterials.

Enormous efforts have focused on the search for materials that could respond to terahertz radiation, a scientific quest to find the building blocks for devices that could take advantage of the frequency for imaging and other applications.

Potential applications could lie in medical imaging or security screening, said Padilla. Materials undetectable through x-ray scans -- such as chemicals, biological agents, and certain explosives -- can provide a unique "fingerprint" when struck by radiation in the far-infrared spectrum. Metamaterials like the one developed by the research team will facilitate future devices operating at the terahertz frequency of the electromagnetic spectrum.

In addition to imaging and screening, researchers and high-tech companies are probing the use of terahertz in switches, modulators, lenses, detectors, high bit-rate communications, secure communications, the detection of chemical and biological agents and characterization of explosives, according to Los Alamos National Laboratory.

Adapted from materials provided by Boston College, via EurekAlert!, a service of AAAS.

New Nanotube Sensor Can Continuously Monitor Minute Amounts Of Insulin

2008-04-19T21:36:00.000-07:00

ScienceDaily (Apr. 17, 2008) — A new method that uses nanotechnology to rapidly measure minute amounts of insulin is a major step toward developing the ability to assess the health of the body's insulin-producing cells in real time.

Among other potential applications, this method could be used to improve the efficacy of a new procedure for treating Type 1 (juvenile) diabetes that has demonstrated the ability to free diabetics from insulin injections for several years. It works by transplanting insulin-producing cells into the pancreas of diabetics to replace the cells that the disease has disabled or destroyed.

The new insulin detection method was developed by a team of Vanderbilt researchers headed by Associate Professor of Chemistry David Cliffel and is reported in the February 18 issue of the journal Analytica Chimica Acta.

To gain this capability, the researchers developed a new electrode for a device called a microphysiometer. The microphysiometer assesses the condition of living cells by submerging them in a saline solution, confining them in a very small chamber and then measuring variations in their metabolism. The volume of the chamber is only three microliters — about 1/20th the size of an ordinary raindrop — allowing the electrode to detect the minute amounts of insulin produced by special pancreatic cells called Islets of Langerhans.

The new electrode is built from multiwalled carbon nanotubes, which are like several flat sheets of carbon atoms stacked and rolled into very small tubes. Provided by William Hofmeister at the University of Tennessee Space Institute, the nanotubes are electrically conductive and the concentration of insulin in the chamber can be directly related to the current at the electrode and the nanotubes operate reliably at pH levels characteristic of living cells.

Current detection methods measure insulin production at intervals by periodically collecting small samples and measuring their insulin levels. The new sensor detects insulin levels continuously by measuring the transfer of electrons produced when insulin molecules oxidize in the presence of glucose. When the cells produce more insulin molecules, the current in the sensor increases and vice versa, allowing the researchers to monitor insulin concentrations in real time. It is similar to a device developed by another group of researchers that operated at acidity levels well beyond those where living cells can function.

Previous tests had shown that nanotube detectors are more sensitive at measuring insulin than conventional methods. However, the researchers had to overcome a major obstacle to adapt them to work in the microphysiometer.

In the small chamber, they found that the fluid moves across the electrode surface rather than pushing against it. These micro-currents tended to sweep the nanotubes aside rather than pinning them to the electrode surface where their electrical activity can be measured. The researchers solved this problem by coating the electrode with a chemical called dihydropyran, a small molecule that forms chains that trap the insulin molecules on the electrode surface.

"One of the key advances of this project was finding how to keep nanotubes active on the surface without being washed away by microfluidic flows," Cliffel says.

Now that the microphysiometer has demonstrated the ability to rapidly detect the small quantities of insulin produced by individual cells, the researchers hope to use it to determine the health of the islet cells used for transplantation.

Researchers at the University of Alberta have shown that islet cells can be transplanted into a Type I diabetic and can greatly relieve insulin dependence for several years. Unfortunately these transplants require large doses of immunosuppressive drugs, and scientists don't yet know how these drugs affect the health of the islet cells.

One of the next steps is to use the microphysiometer to measure insulin, lactate and oxygen levels simultaneously. This will allow researchers to study how the islet cells react to the drugs and help identify the best way to deal with transplant rejection. It will also allow them to verify the health of the islets cells before they are transplanted into patients.

The research was funded in part by the Vanderbilt Institute of Integrative Biosystems Research and Education and by a pilot project grant from Vanderbilt Diabetes Research and Training Center, supported by the National Institutes of Health. It was performed with islet cells isolated from mice at the Vanderbilt Diabetes Research and Training Center.

Other authors of the study include graduate student Rachel M. Snider, research assistant professor Madalina Ciobanu, and former undergraduate researcher Amy E. Rue.

Adapted from materials provided by Vanderbilt University.

World's Newest and Fastest Survey Telescope Receives New Mirror

2008-04-19T21:28:00.000-07:00

ScienceDaily (Apr. 17, 2008) — A 4.1-metre diameter primary mirror, a vital part of the world's newest and fastest survey telescope, VISTA (the Visible and Infrared Survey Telescope for Astronomy) has been delivered to its new mountaintop home at Cerro Paranal, Chile. The mirror will now be coupled with a small camera for initial testing prior to installing the main camera in June. Full scientific operations are due to start early next year. VISTA will form part of ESO's Very Large Telescope facility.

The mirror arrived over the Easter weekend at the Paranal Observatory where the telescope is being assembled at an altitude of 2518m, in Chile's Atacama Desert.

VISTA Project Manager Alistair McPherson from STFC's UK Astronomy Technology Centre (UK ATC) accompanied the mirror on its journey to Chile: "This is a major milestone for the VISTA project. The precious mirror was loaded on to a plane in a special cradle that used tennis balls to cushion it from impact for its arduous journey across three continents. "

"The mirror had a difficult four-day journey, by air and by road. It arrived in perfect condition and now that it has been coated, we will install the mirror in the telescope with a small test camera for about four weeks testing. We plan to install the main camera in June," said the Project Scientist on VISTA, Will Sutherland of Queen Mary, University of London, UK.

The VISTA 4.1-metre diameter primary mirror is the most strongly curved large mirror ever polished to such a precise and exacting surface accuracy - deviations from a perfect surface of less than 1/3000th of the thickness of a human hair. On arrival at Cerro Paranal it was safely craned into the telescope dome where it was washed and coated with a thin layer of protected silver in the facility's coating plant. Silver is the best metal for the purpose since it reflects over 98% of near-infrared light, better than the more commonly used aluminium. To date, the reflectivity produced by the silver coating- a relatively new venture - is well above that specified and exceeds all other telescopes.

VISTA will survey large areas of the southern sky at near infrared wavelengths (2 to 4 times the wavelength of visible light) to study objects that are not seen easily in optical light either because they are too cool (such as brown dwarfs), or are surrounded by interstellar dust which infrared light penetrates much better than optical, or whose optical light is redshifted into the near infrared by the expansion of the Universe.

Amongst other things VISTA's surveys will help our understanding of the nature and distribution and origin of known types of stars and galaxies, map the 3-D structure of our galaxy, and help determine the relation between the 3-D structure of the universe and the mysterious 'dark energy' and dark matter'. Samples of objects will be followed up in detail with further observations by other telescopes and instruments such as the nearby Very Large Telescope.

"The delivery of the last component of VISTA is a significant milestone and we are delighted with the progress made since the mirror arrived. Now astronomers can really look forward to being able to perform unparalleled observing of our Southern skies," said Richard Wade, President of the ESO Council and STFC Chief Operating Officer.

VISTA is a 55 million euro project, funded by grants from the UK DTI's Joint Infrastructure Fund and the STFC to Queen Mary, University of London, the lead institute of the VISTA Consortium. VISTA forms part of the UK's subscription to ESO and will be an ESO telescope.

Adapted from materials provided by ESO.

Comet Collides With Solar Hurricane

2008-04-19T21:16:00.000-07:00

ScienceDaily (Oct. 1, 2007) — A NASA satellite has captured the first images of a collision between a comet and a solar hurricane. It is the first time scientists have witnessed such an event on another cosmic body. One of NASA's pair of Solar Terrestrial Relations Observatory satellites, known as STEREO, recorded the event April 20.

The phenomenon was caused by a coronal mass ejection, a large cloud of magnetized gas cast into space by the sun. The collision resulted in the complete detachment of the plasma tail of Encke's comet. Observations of the comet reveal the brightening of its tail as the coronal mass ejection swept by and the tail's subsequent separation as it was carried away by the front of the ejection.

"We were awestruck when we saw these images," says Angelos Vourlidas, lead author and researcher at the Naval Research Laboratory, Washington. "This is the first time we've witnessed a collision between a coronal mass ejection and a comet and the surprise of seeing the disconnection of the tail was the icing on the cake."

Encke's comet was traveling within the orbit of Mercury when a coronal mass ejection first crunched the tail then ripped it completely away. The comet is only the second repeating, or periodic, comet ever identified. Halley's comet was the first.

Scientists at the Naval Research Laboratory made the observations using the Heliospheric Imager in its Sun Earth Connection Coronal and Heliospheric Investigation telescope suite aboard the STEREO-A spacecraft. Coronal mass ejections are violent eruptions with masses greater than a few billion tons. They travel from 60 to more than 2,000 miles per second.

They have been compared to hurricanes because of the widespread disruption they can cause when directed at Earth. These solar hurricanes cause geomagnetic storms that can present hazards for satellites, radio communications and power systems. However, coronal mass ejections are spread over a large volume of space, mitigating their mass and power to create an impact softer than a baby's breath.

Scientists have been aware of the disconnection of the entire plasma tail of a comet for some time, but the conditions that lead to these events remained a mystery. It was suspected that coronal mass ejections could be responsible for some of the disconnected events, but the interaction between a coronal mass ejection and a comet never had been observed.

Preliminary analysis suggests the disconnection likely is triggered by what is known as magnetic reconnection, in which the oppositely directed magnetic fields around the comet are crunched together by the magnetic fields in the coronal mass ejection. The comet fields suddenly link together, reconnecting, to release a burst of energy that detaches the comet's tail. A similar process takes place in Earth's magnetosphere during geomagnetic storms, powering the aurora borealis and other phenomena.

Comets are icy leftovers from the solar system's formation billions of years ago. They usually reside in the cold, distant regions of the solar system. Occasionally, the gravitational tug from a planet, another comet or a nearby star sends a comet into the inner solar system, where the sun's heat and radiation vaporizes gas and dust from the comet to form its tail. Comets typically have two tails: one of dust and a fainter one of electrically conducting gas called plasma.

"Even though STEREO is primarily designed to study coronal mass ejections, particularly their impact on Earth, we hope this impact will provide many insights to scientists studying comets," said Michael Kaiser, STEREO project scientist at NASA's Goddard Space Flight Center, Greenbelt, Md.

The results will be published in the Oct. 10 issue of the Astrophysical Journal Letters.

View animation at: http://www.nasa.gov/mpg/191092main_encke_visualization.mpg

Adapted from materials provided by NASA, Goddard Space Flight Center.

Platinum Nanocube Makes Hydrogen Fuel Cells Cheaper And More Efficient

2008-04-19T13:34:00.000-07:00

ScienceDaily (Apr. 18, 2008) — Two great obstacles to hydrogen-powered vehicles lie with fuel cells. Fuel cells, which like batteries produce electrical power through chemical reactions, have been plagued by their relatively low efficiency and high production costs. Scientists have tested a wide assortment of metals and materials to overcome the twin challenge.

Now a team led by Shouheng Sun, professor of chemistry at Brown, has mastered a Rubik’s Cube-like dilemma for dealing with platinum, a precious metal coveted for its ability to boost a chemical reaction in fuel cells. The team shows that shaping platinum into a cube greatly enhances its efficiency in a phase of the fuel cell’s operation known as oxygen reduction reaction. Sun’s results have been published online in the journal Angewandte Chemie. The paper was selected as a Very Important Paper, a distinction reserved for less than 5 percent of manuscripts submitted to the peer-reviewed journal.

Platinum helps reduce the energy barrier – the amount of energy needed to start a reaction – in the oxidation phase of a fuel cell. It is also seen as beneficial on the other end of the fuel cell, known as the cathode. There, platinum has been shown to assist in oxygen reduction, a process in which electrons peeled from hydrogen atoms join with oxygen atoms to create electrical energy. The reaction also is important because it only produces water. This byproduct – rather than the global warming gas carbon dioxide – is a big reason why hydrogen fuel cells are a tantalizing area of research from automakers in Detroit to policy-makers in Washington.

Scientists, however, have had trouble maximizing platinum’s potential in the oxygen reduction reaction. The barriers chiefly revolve around shape and surface area – geometry and geography, so to speak. What Sun has learned is that molding platinum into a cube on the nanoscale enhances its catalysis – that is, it boosts the rate of a chemical reaction.

“For the first time, we can control the morphology of the particle to make it more like a cube,” Sun said. “People have had very limited control over this process before. Now we have shown it can be done uniformly and consistently.”

During his experiments, Sun, along with Brown graduate engineering student Chao Wang and engineers from the Japanese firm Hitachi Maxwell Ltd., created polyhedron and cube shapes of different sizes by adding platinum acetylacetonate (Pt(acac)2) and a trace amount of iron pentacarbonyl (Fe(CO)5) at specific temperature ranges. The team found that cubes were more efficient catalysts, owing largely to their surface structure and their resistance to being absorbed by the sulfate in the fuel cell solution.

“For this reaction, the shape is more important than the size,” Sun said.

The next step, Sun added, is to build a polymer electrolyte membrane fuel cell and test the platinum nanocubes as catalysts in it. The team expects the experiments will yield fuel cells with a higher electrical output than previous versions.

“It’s like science fiction, but we’re a step closer now to the reality of developing a very efficient platinum catalyst for hydrogen cars that produce only water as exhaust,” Sun said.

Hitachi Maxell chemical engineers Hideo Daimon, Taigo Ondera and Tetsunori Koda, a visiting engineer at Brown, contributed to the research.

The research was funded by the National Science Foundation and by the Office of the Vice President for Research at Brown University through its Research Seed Fund.

Adapted from materials provided by Brown University.

Silent Tiny Cooling Systems Made For Laptop Computers, Other Devices

2008-04-19T13:28:00.000-07:00

ScienceDaily (Mar. 20, 2008) — Engineers harnessing the same physical property that drives silent household air purifiers have created a miniaturized device that is now ready for testing as a silent, ultra-thin, low-power and low maintenance cooling system for laptop computers and other electronic devices.

The compact, solid-state fan, developed with support from NSF's Small Business Innovation Research program, is the most powerful and energy efficient fan of its size. It produces three times the flow rate of a typical small mechanical fan and is one-fourth the size.

Dan Schlitz and Vishal Singhal of Thorrn Micro Technologies, Inc., of Marietta, Ga. will present their RSD5 solid-state fan at the 24th Annual Semiconductor Thermal Measurement, Modeling and Management Symposium (Semi-Therm) in San Jose, Calif., on March 17, 2008. The device is the culmination of six years of research that began while the researchers were NSF-supported graduate students at Purdue University.

"The RSD5 is one of the most significant advancements in electronics cooling since heat pipes. It could change the cooling paradigm for mobile electronics," said Singhal.

The RSD5 incorporates a series of live wires that generate a micro-scale plasma (an ion-rich gas that has free electrons that conduct electricity). The wires lie within un-charged conducting plates that are contoured into half-cylindrical shape to partially envelop the wires.

Within the intense electric field that results, ions push neutral air molecules from the wire to the plate, generating a wind. The phenomenon is called corona wind.

"The technology is a breakthrough in the design and development of semiconductors as it brings an elegant and cost effective solution to the heating problems that have plagued the industry," said Juan Figueroa, the NSF SBIR program officer who oversaw the research.

With the breakthrough of the contoured surface, the researchers were able to control the micro-scale discharge to produce maximum airflow without risk of sparks or electrical arcing. As a result, the new device yields a breeze as swift as 2.4 meters per second, as compared to airflows of 0.7 to 1.7 meters per second from larger, mechanical fans.

The contoured platform is a part of the device heat sink, a trick that enabled Schlitz and Singhal to both eliminate some of the device's bulk and increase the effectiveness of the airflow.

"The technology has the power to cool a 25-watt chip with a device smaller than 1 cubic-cm and can someday be integrated into silicon to make self-cooling chips," said Schlitz.

This device is also more dust-tolerant than predecessors. While dust attraction is ideal for living-room-scale fans that that provide both air flow and filtration, debris can be a devastating obstacle when the goal is to cool an electrical component.

Adapted from materials provided by National Science Foundation.

New Robots Can Provide Elder Care For Aging Baby Boomers

2008-04-19T13:16:00.000-07:00

ScienceDaily (Apr. 16, 2008) — Baby boomers are set to retire, and robots are ready to help, providing elder care and improving the quality of life for those in need. Researchers at the University of Massachusetts Amherst have developed a robotic assistant that can dial 911 in case of emergencies, remind clients to take their medication, help with grocery shopping and allow a client to talk to loved ones and health care providers.

Concerned family members can access the unit and visit their elderly parents from any Internet connection, including navigating around the home and looking for Mom or Dad, who may not hear the ringing phone or may be in need of assistance. Doctors can perform virtual house calls, reducing the need for travel.

“For the first time, robots are safe enough and inexpensive enough to do meaningful work in a residential environment,” says computer scientist Rod Grupen, director of UMass Amherst’s Laboratory for Perceptual Robotics, who developed project ASSIST with computer scientists Allen Hanson and Edward Riseman.

The robot, called the uBOT-5, could allow elders to live independently, and provide relief for caregivers, the medical system and community services, which are expected to be severely stressed by the retirement of over 77 million Americans in the next 30 years.

There is no mistaking the uBot-5 for a person, but its design was inspired by human anatomy. An array of sensors acts as the robots eyes and ears, allowing it to recognize human activities, such as walking or sitting. It can also recognize an abnormal visual event, such as a fall, and notify a remote medical caregiver. Through an interface, the remote service provider may ask the client to speak, smile or raise both arms, movements that the robot can demonstrate. If the person is unresponsive, the robot can call 911, alert family and apply a digital stethoscope to a patient, conveying information to an emergency medical technician who is en route.

The system also tracks what isn’t human. If a delivery person leaves a package in a hallway, the sensor array is trained to notice when a path is blocked, and the robot can move the obstruction out of the way. It can also raise its outstretched arms, carry a load of about 2.2 pounds and has the potential to perform household tasks that require a fair amount of dexterity, including cleaning and grocery shopping.

The uBOT-5 carries a Web cam, a microphone, and a touch-sensitive LCD display that acts as an interface for communication with the outside world. “Grandma can take the robot’s hand, lead it out into the garden and have a virtual visit with a grandchild who is living on the opposite coast,” says Grupen, who notes that isolation can lead to depression in the elderly.

Grupen studied developmental neurology in his quest to create a robot that could do a variety of tasks in different environments. The uBot-5’s arm motors are analogous to the muscles and joints in our own arms, and it can push itself up to a vertical position if it falls over. It has a “spinal cord” and the equivalent of an inner ear to keep it balanced on its Segway-like wheels.

The researchers wanted to create a personal robot that could provide many services, such as a medical alert system, or the means to talk to loved ones, all in one human-like package, according to Grupen. To evaluate the effectiveness of potential technologies, the research team worked with social workers, members of the medical community and family members of those in elder care.

The collaborative effort, dubbed project ASSIST, involved researchers from the Smith College School for Social Work, the Veteran’s Administration (Connecticut Health Care System, West Haven campus) and elder care community centers in western Massachusetts. Through focus groups, the researchers learned about the preferences of potential users.

Graduate students Patrick Deegan, Emily Horrell, Shichao Ou, Sharaj Sen, Brian Thibodeau, Adam Williams and Dan Xie are also collaborators on project ASSIST.

Adapted from materials provided by University of Massachusetts Amherst.

How Nanocluster Contaminants Increase Risk Of Spreading Through GroundwaterHow Nanocluster Contaminants Increase Risk Of Spreading Through Groundwater

2008-04-19T12:54:00.000-07:00

ScienceDaily (Apr. 17, 2008) — For almost half a century, scientists have struggled with plutonium contamination spreading further in groundwater than expected, increasing the risk of sickness in humans and animals.
It was known nanometer sized clusters of plutonium oxide were the culprit, but no one had been able to study its structure or find a way to separate it from the groundwater.

Scientists at the U.S. Department of Energy's Argonne National Laboratory, in collaboration with researchers from the University of Notre Dame, were able to use high-energy X-rays from the Argonne Advanced Photon Source to finally discover and study the structure of plutonium nanoclusters.

"When plutonium forms into the clusters, its chemistry is completely different and no one has really been able to assess what it is, how to model it or how to separate it Argonne senior chemist Lynda Soderholm said. "People have known about and tried to understand the nanoclusters, but it was the modern analytical techniques and the APS that allowed us understand what it is."

The nanoclusters are made up of exactly 38 plutonium atoms and had almost no charge. Unlike stray plutonium ions, which carry a positive charge, they are not attracted to the electrons in plant life, minerals, etc. which stopped the ions' progression in the ground water.

Models have been based on the free-plutonium model, creating discrepancies between what is expected and reality. Soderholm said that with knowledge of the structure, scientists can now create better models to account for not only free-roaming plutonium ions, but also the nanoclusters.

The clusters also are a problem for plutonium remediation. The free ions are relatively easy to separate out from groundwater, but the clusters are difficult to remove.

"As we learn more, we will be able to model the nanoclusters and figure out how to break them apart," Soderholm said. "Once they are formed, they are very hard to get rid of."

Soderholm said other experiments have shown some clusters with different numbers of plutonium atoms and she plans to examine -- together with her collaborators S. Skanthakumar, Richard Wilson and Peter Burns of Argonne's Chemical Sciences and Engineering Division-- the unique electric and magnetic properties of the clusters.

Funding for the research was provided by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences.

Adapted from materials provided by DOE/Argonne National Laboratory, via EurekAlert!, a service of AAAS.

Tiny Sensor Developed To Detect Homemade Bombs

2008-04-18T20:21:00.001-07:00

ScienceDaily (Mar. 19, 2008) — A team of chemists and physicists at the University of California, San Diego has developed a tiny, inexpensive sensor chip capable of detecting trace amounts of hydrogen peroxide, a chemical used in the most common form of homemade explosives.
The invention and operation of this penny-sized electronic sensor, capable of sniffing out hydrogen peroxide vapor in the parts-per-billion range from peroxide-based explosives, such as those used in the 2005 bombing of the London transit system, is detailed in a new article.*In addition to detecting explosives, UC San Diego scientists say the sensor could have widespread applications in improving the health of industrial workers by providing a new tool to inexpensively monitor the toxic hydrogen peroxide vapors from bleached pulp and other products to which factory workers are exposed.

“The detection capability of this tiny electronic sensor is comparable to current instruments, which are large, bulky and cost thousands of dollars each,” said William Trogler, a professor of chemistry and biochemistry at UCSD and one of its inventors. “If this device were mass produced, it’s not inconceivable that it could be made for less than a dollar.”

The device was invented by a team led by Trogler; Andrew Kummel, a professor of chemistry and biochemistry; and Ivan Schuller, a professor of physics. Much of the work was done by UCSD chemistry and physics graduate students Forest Bohrer, Corneliu Colesniuc and Jeongwon Park.

The sensor works by monitoring the variability of electrical conductivity through thin films of “metal phthalocyanines.” When exposed to most oxidizing agents, such as chlorine, these metal films show an increase in electrical current, while reducing agents have the opposite effect—a decrease of electrical current.

But when exposed to hydrogen peroxide, an oxidant, the metal phthalocyanine films behave differently depending on the type of metal used. Films made of cobalt phthalocyanine show decreases in current, while those made from copper or nickel show increases in current.

The UCSD team used this unusual trait to build their sensor. It is composed of thin films of both cobalt phthalocyanine and copper phthalocyanine to display a unique signature whenever tiny amounts of hydrogen peroxide are present.

Bombs constructed with hydrogen peroxide killed more than 50 people and injured 700 more on two London subway trains and a transit bus during rush hour on July 7, 2005. More than 1,500 pounds of a hydrogen peroxide-based mixture was discovered after an alleged bomb plot in Germany that resulted in the widely publicized arrest last September of three people.

Trogler said that because the team’s sensor is so little affected by water vapor, it can be used in industrial and other “real-life applications.” The university has applied for a patent on the invention, which has not yet been licensed.

The article Selective Detection of Vapor Phase Hydrogen Peroxide with Phthalocyanine Chemiresistors is published in the Journal of the American Chemical Society.

Funding for the research study was provided by the Air Force Office of Scientific Research.

Adapted from materials provided by University of California - San Diego.

Graphene Used To Create World's Smallest Transistor

2008-04-18T20:13:00.000-07:00

ScienceDaily (Apr. 18, 2008) — Researchers have used the world's thinnest material to create the world's smallest transistor, one atom thick and ten atoms wide.
Reporting their peer-reviewed findings in the journal Science, Dr Kostya Novoselov and Professor Andre Geim from The School of Physics and Astronomy at The University of Manchester show that graphene can be carved into tiny electronic circuits with individual transistors having a size not much larger than that of a molecule.

The smaller the size of their transistors the better they perform, say the Manchester researchers.

In recent decades, manufacturers have crammed more and more components onto integrated circuits. As a result, the number of transistors and the power of these circuits have roughly doubled every two years. This has become known as Moore's Law.

But the speed of cramming is now noticeably decreasing, and further miniaturisation of electronics is to experience its most fundamental challenge in the next 10 to 20 years, according to the semiconductor industry roadmap.

At the heart of the problem is the poor stability of materials if shaped in elements smaller than 10 nanometres* in size. At this spatial scale, all semiconductors -- including silicon -- oxidise, decompose and uncontrollably migrate along surfaces like water droplets on a hot plate.

Four years ago, Geim and his colleagues discovered graphene, the first known one-atom-thick material which can be viewed as a plane of atoms pulled out from graphite. Graphene has rapidly become the hottest topic in physics and materials science.

Now the Manchester team has shown that it is possible to carve out nanometre-scale transistors from a single graphene crystal. Unlike all other known materials, graphene remains highly stable and conductive even when it is cut into devices one nanometre wide.

Graphene transistors start showing advantages and good performance at sizes below 10 nanometres - the miniaturization limit at which the Silicon technology is predicted to fail.

"Previously, researchers tried to use large molecules as individual transistors to create a new kind of electronic circuits. It is like a bit of chemistry added to computer engineering", says Novoselov. "Now one can think of designer molecules acting as transistors connected into designer computer architecture on the basis of the same material (graphene), and use the same fabrication approach that is currently used by semiconductor industry".

"It is too early to promise graphene supercomputers," adds Geim. "In our work, we relied on chance when making such small transistors. Unfortunately, no existing technology allows the cutting materials with true nanometre precision. But this is exactly the same challenge that all post-silicon electronics has to face. At least we now have a material that can meet such a challenge."

"Graphene is an exciting new material with unusual properties that are promising for nanoelectronics", comments Bob Westervelt, professor at Harvard University. "The future should be very interesting".

*One nanometre is one-millionth of a millimetre and a single human hair is around 100,000 nanometres in width.

A paper entitled "Chaotic Dirac Billiard in Graphene Quantum Dots" is published in April 17 issue of Science. It is accompanied by a Perspective article entitled "Graphene Nanoelectronics" by Westervelt.

Adapted from materials provided by University of Manchester.

Aerodynamic Truck Trailer Cuts Fuel And Emissions By Up To 15 Percent

2008-04-18T20:04:00.000-07:00

ScienceDaily (Apr. 17, 2008) — Creating an improved aerodynamic shape for truck trailers by mounting sideskirts can lead to a cut in fuel consumption and emissions of up to as much as 15%. Earlier promising predictions, based on mathematical models and wind tunnel tests by TU Delft, have been confirmed during road tests with an adapted trailer. This means that PART (Platform for Aerodynamic Road Transport), the public-private partnership platform, has produced an application which can immediately be put into production.
It is expected that the cost of fitting aerodynamically-shaped sideskirts will be recouped within two years. Furthermore, the sideskirts can be fitted to approximately half the trucks currently in use in the Netherlands as the skirts can also be retrofitted.

Carbon Dioxide reduction

Prof. Michel van Tooren of TU Delft’s Aerospace Engineering faculty: 'In 2005, 10,000 new trailers were taken into use in the Netherlands. With an average fuel consumption of 30 litres per 100 kilometres, that translates into 750 million litres of diesel consumption in the Netherlands each year. We can cut fuel consumption by 5% or more for 50% of those trailers. That means a reduction of 50 million tons of CO2 emissions a year. This research can therefore result in a substantial, structural contribution to cutting fuel consumption and an annual saving of tens of millions of Euros, next to that cut in CO2 emissions by the road transport sector.'

He continues: 'Together with this sector we have created a practical platform for further research and development, but we still need active government participation. Just obtaining permits for all the road tests has involved a huge amount of time, energy and frustration. The next step is realizing a practical partnership between the government and industry in order to put the solutions into practice.'

About sideskirts

Sideskirts are plates which are mounted on the sides of trailers, primarily with a view to underrun protection. The new aerodynamic design of the sideskirts substantially reduces the air currents alongside and under the trailer and thereby also the air resistance. Initial driving tests with a trailer equipped with the aerodynamic sideskirts over a straight stretch of public road revealed a cut in fuel consumption of between 5% and 15%. Subsequent research comprising long-term operational tests by TNT displayed a fuel reduction of 10%. These results confirm the calculations and findings from the wind tunnel tests: these had already established that the observed 14 - 18% reduction in air resistance led to 7 - 9% less fuel consumption. In practice, the figures are in fact even better.

About the boat tail

Road tests have also already been initiated on what are known as boat tails. These constructions on the rear of a trailer ensure a reduction in the wake: the vacuum and air currents which arise when the trailer is moving. In theory, a boat tail could also mean a cut in air resistance of 30%, with a fuel reduction of 10 - 15%. These road tests should also confirm the earlier, highly positive results from the windtunnel.

Incidentally, this study does not aim to produce boat tails for commercial use. Limitations in their practical use, in particular when loading and unloading, safety aspects and problems with exceeding maximum vehicle sizes prevent these being used for many types of vehicles. This research focuses on gaining knowledge and developing different practicable solutions; the second development phase will concentrate on these aims.

About PART

The objective of PART, a partnership between TU Delft, TNT, Scania Beers BV, FOCWA Carrosseriebouw, Ephicas, Kees Mulder Carrosserieën, Van Eck Carrosseriebouw, Syntens, Squarell Technology, Emons Group and NEA transport research and training, is to develop and test aerodynamic applications for trailers. In contrast to research into the aerodynamic properties of trucks, comparable research into trailers is still relatively new. Applications such as the Ephicas sideskirts or boat tails could lead to reductions in air resistance of up to 30%, which translates into a reduction in fuel consumption and emissions of as much as 15%. Moreover, it contributes to increasing profits in the highly competitive world of road transport.

Adapted from materials provided by Delft University of Technology.

Nuclear Power: Most Successful Fuel Performance Ever For US Advanced Gas Reactor Fuel

2008-04-18T19:57:00.000-07:00

ScienceDaily (Apr. 15, 2008) — Advanced gas reactors offer more efficient operation, less waste disposal and other benefits over water-cooled reactor designs used in U.S. nuclear power plants.

But creating fuel that burns efficiently and reliably in the higher temperatures of advanced gas reactors has been a challenge -- until now.

Fuel fabricated at Oak Ridge National Laboratory, in cooperation with Idaho National Laboratory and the Babcock & Wilcox Company, has demonstrated the most successful performance ever for U.S. advanced gas reactor fuel.

In recent tests at the Advanced Test Reactor at INL, the ORNL fuel achieved 9 percent burn-up, a significant milestone on its way to a target of 16-18 percent.

Higher burn-up allows for more efficient use of uranium and less waste compared to the 3-4 percent rate of standard fuel at U.S. power plants.

his experiment is the first of eight planned to qualify fuel as part of the Department of Energy's Next Generation Nuclear Power Plant project.

The fuel elements are built from thousands of tiny uranium-containing spheres coated with carbon and silicon carbide to contain the radioactive fission products. The coated particles are compacted by a special process into fuel sticks and loaded into a graphite form.

The fuel work for this first test was conducted in ORNL's Materials Science and Technology Division and funded by DOE's Office of Nuclear Energy.

Adapted from materials provided by DOE/Oak Ridge National Laboratory.

Water Needed To Produce Various Types Of Energy

2008-04-18T19:46:00.000-07:00

ScienceDaily (Apr. 17, 2008) — It is easy to overlook that most of the energy we consume daily, such as electricity or natural gas, is produced with the help of a dwindling resource – fresh water. Virginia Tech professor Tamim Younos and undergraduate student Rachelle Hill are researching the water-efficiency of some of the most common energy sources and power generating methods.
Younos, associate director at the Virginia Water Resources Research Center based at Virginia Tech and research professor of water resources in the College of Natural Resources and undergraduate researcher Hill, of Round Hill, Va., majoring in environmental science and aquatic resource concentration, in the College of Agriculture and Life Sciences, have analyzed 11 types of energy sources, including coal, fuel ethanol, natural gas, and oil; and five power generating methods, including hydroelectric, fossil fuel thermoelectric, and nuclear methods.

Younos said they based their calculations on available governmental reports by using a standard measurement unit, which makes this study unique. “Our unit is gallons of water per British Thermal Unit (BTU),” explained Younos. “We selected BTU as a standard unit because it indicates pure energy as heat and is applicable to all energy production and power generation methods.”

According to the study, the most water-efficient energy sources are natural gas and synthetic fuels produced by coal gasification. The least water-efficient energy sources are fuel ethanol and biodiesel.

In terms of power generation, Younos and Hill have found that geothermal and hydroelectric energy types use the least amount of water, while nuclear plants use the most.

Hill took the study one step further and calculated how many gallons of water are required to burn one 60-watt incandescent light bulb for 12 hours a day, over the course of one year. She found that the bulb would consume between 3,000 and 6,000 gallons of water, depending on how water-efficient the power plant that supplies the electricity is.

Hill added that the results are estimates of the water consumption based on energy produced by fossil fuel thermoelectric plants, which produce most of the Unites State’s power – about 53 percent. “The numbers are even more staggering if you multiply the water consumed by the same light bulb by the approximately 111 million U.S. homes,” said Hill. “The water usage then gets as high as 655 billion gallons of water a year.”

By contrast, burning a compact fluorescent bulb for the same amount of time would save about 2,000 to 4,000 gallons of water per year.

Younos noted that the results of this analysis should be interpreted with a grain of salt. “There are several variables such as geography and climate, technology type and efficiency, and accuracy of measurements that come into play. However, by standardizing the measurement unit, we have been able to obtain a unique snapshot of the water used to produce different kinds of energy.”

Adapted from materials provided by Virginia Tech, via Newswise.

Electric Solar Wind Sail Could Power Future Space Travel In Solar System

2008-04-18T19:41:00.000-07:00

ScienceDaily (Apr. 17, 2008) — The electric solar wind sail developed at the Finnish Meteorological Institute two years ago has moved rapidly from invention towards implementation. Electric sail propulsion might have a large impact on space research and space travel throughout the solar system.
The electric solar wind sail developed by Dr. Pekka Janhunen might revolutionise travelling in space. The electric sail uses the solar wind as its thrust source and therefore needs no fuel or propellant. The solar wind is a continuous plasma stream emanating from the Sun. Changes in the properties of the solar wind cause auroral brightening and magnetic storms, among other things.

The main parts of the device are long metallic tethers and a solar-powered electron gun which keeps the tethers positively charged. The solar wind exerts a small but continuous thrust on the tethers and the spacecraft.

“We haven't encountered major problems in any of the technical fields thus far. This has already enabled us to start planning the first test mission,” says Dr. Pekka Janhunen. An important subgoal was reached when the Electronics Research Laboratory of the University of Helsinki managed to develop a method for constructing a multiline micrometeoroid-resistant tether out of very thin metal wires using ultrasonic welding. The newly developed technique allows the bonding together of thin metal wires in any geometry; thus, the method might also have spinoff applications outside the electric sail.

Electric Sail For Space Travel

The electric sail could enable faster and cheaper solar system exploration. It might also enable economic utilisation of asteroid resources for, e.g. producing rocket fuel in orbit.

“The electric sail might lower the cost of all space activities and thereby, for example, help making large solar power satellites a viable option for clean electricity production. Solar power satellites orbiting in the permanent sunshine of space could transmit electric power to Earth by microwaves without interruptions. Continuous power would be a major benefit compared to, e.g. ground-based solar power where storing the energy over night, cloudy weather and winter are tricky issues, especially here in the far North,” says Dr. Pekka Janhunen.

Component work for the electric sail was carried out at the University of Helsinki and in Germany, Sweden, Russia and Italy. The electric sail was invented as a by-product of basic research done at the Finnish Meteorological Institute on the interaction of the solar wind with planets and their atmospheres. Work on the electric sail in Finland is currently funded by the Academy of Finland and private foundations.

The first international electric sail meeting will be arranged at ESA ESTEC in Noordwijk, The Netherlands on May 19, 2008.

Adapted from materials provided by Finnish Meteorological Institute.

Newly Discovered Fundamental State Of Matter, A Superinsulator, Has Been Created

2008-04-11T13:40:00.000-07:00

ScienceDaily (Apr. 9, 2008) — Superinsulation may sound like a marketing gimmick for a drafty attic or winter coat. But it is actually a newly discovered fundamental state of matter created by scientists at the U.S. Department of Energy's Argonne National Laboratory in collaboration with several European institutions. This discovery opens new directions of inquiry in condensed matter physics and breaks ground for a new generation of microelectronics.
Led by Argonne senior scientist Valerii Vinokur and Russian scientist Tatyana Baturina, an international team of scientists from Argonne, Germany, Russia and Belgium fashioned a thin film of titanium nitride which they then chilled to near absolute zero. When they tried to pass a current through the material, the researchers noticed that its resistance suddenly increased by a factor of 100,000 once the temperature dropped below a certain threshold. The same sudden change also occurred when the researchers decreased the external magnetic field.

Like superconductors, which have applications in many different areas of physics, from accelerators to magnetic-levitation (maglev) trains to MRI machines, superinsulators could eventually find their way into a number of products, including circuits, sensors and battery shields.

If, for example, a battery is left exposed to the air, the charge will eventually drain from it in a matter of days or weeks because the air is not a perfect insulator, according to Vinokur. "If you pass a current through a superconductor, then it will carry the current forever; conversely, if you have a superinsulator, then it will hold a charge forever," he said.

"Titanium nitride films, as well as films prepared from some other materials, can be either superconductors or insulators depending on the thickness of the film," Vinokur said. "If you take the film which is just on the insulating side of the transition and decrease the temperature or magnetic field, then the film all of a sudden becomes a superinsulator."

Scientists could eventually form superinsulators that would encapsulate superconducting wires, creating an optimally efficient electrical pathway with almost no energy lost as heat. A miniature version of these superinsulated superconducting wires could find their way into more efficient electrical circuits.

Titanium nitride's sudden transition to a superinsulator occurs because the electrons in the material join together in twosomes called Cooper pairs. When these Cooper pairs of electrons join together in long chains, they enable the unrestricted motion of electrons and the easy flow of current, creating a superconductor. In superinsulators, however, the Cooper pairs stay separate from each other, forming self-locking roadblocks.

"In superinsulators, Cooper pairs avoid each other, creating enormous electric forces that oppose penetration of the current into the material," Vinokur said. "It's exactly the opposite of the superconductor," he added.

The theory behind the experiment stemmed from Argonne's Materials Theory Institute, which Vinokur organized six years ago in the laboratory's Materials Science Division. The MTI hosts a handful of visiting scholars from around the world to perform cutting-edge research on the most pressing questions in condensed matter physics. Upon completion of their tenure at Argonne, these scientists return to their home institutions but continue to collaborate on the joint projects. The MTI attracts the world's best condensed matter scientists, including Russian "experimental star" Tatyana Baturina, who, according to Vinokur, "became a driving force in our work on superinsulators."

Scientists from the Institute of Semiconductor Physics in Novosibirsk, Russia, Regensburg and Bochum universities in Germany and Interuniversity Microelectronics Centre in Leuven, Belgium, also participated in the research.

The research appears in the April 3 issue of Nature.

Adapted from materials provided by DOE/Argonne National Laboratory.

'Quantum Logic Clock' Rivals Mercury Ion As World's Most Accurate Clock

2008-04-11T13:34:00.000-07:00

ScienceDaily (Mar. 10, 2008) — An atomic clock that uses an aluminum atom to apply the logic of computers to the peculiarities of the quantum world now rivals the world's most accurate clock, based on a single mercury atom. Both clocks are at least 10 times more accurate than the current U.S. time standard.
The measurements were made in a yearlong comparison of the two next-generation clocks, both designed and built at the Commerce Department's National Institute of Standards and Technology (NIST). The clocks were compared with record precision, allowing scientists to measure the relative frequencies of the two clocks to 17 digits-the most accurate measurement of this type ever made. The comparison produced the most precise results yet in the worldwide quest to determine whether some of the fundamental constants that describe the universe are changing slightly over time, a hot research question that may alter basic models of the cosmos.

The research is described in the March 6 issue of Science Express.* The aluminum and mercury clocks are both based on natural vibrations in ions (electrically charged atoms) and would neither gain nor lose one second in over 1 billion years-if they could run for such a long time-compared to about 80 million years for NIST-F1, the U.S. time standard based on neutral cesium atoms.

The mercury clock was first demonstrated in 2000 and is now four times better than its last published evaluation in 2006, thanks to ongoing improvements in the clock design and operation. The mercury clock continues its reign as the world's most accurate for now, by a margin of 20 percent over the aluminum clock, but the designers say both experimental clocks could be improved further.

"The aluminum clock is very accurate because it is insensitive to background magnetic and electric fields, and also to temperature," says Till Rosenband, the NIST physicist who built the clock and is the first author of the new paper. "It has the lowest known sensitivity of any atomic clock to temperature, which is one of the most difficult uncertainties to calibrate."

Both the aluminum clock and the mercury clock are based on ions vibrating at optical frequencies, which are 100,000 times higher than microwave frequencies used in NIST-F1 and other similar time standards around the world. Because optical clocks divide time into smaller units, they can be far more precise than microwave standards. NIST scientists have several other optical atomic clocks in development, including one based on thousands of neutral strontium atoms. The strontium clock recently achieved twice the accuracy of NIST-F1, but still trails the mercury and aluminum clocks.

Highly accurate clocks are used to synchronize telecommunications networks and deep-space communications, and for satellite navigation and positioning. Next-generation clocks may also lead to new types of gravity sensors, which have potential applications in exploration for underground natural resources and fundamental studies of the Earth.

Laboratories around the world are developing optical clocks based on a variety of different designs and atoms; it is not yet clear which design will emerge as the best candidate for the next international standard.

The new paper provides the first published evaluation of the operational quantum logic clock, so-named because it is based on the logical reasoning process used in quantum computers (see sidebar for details). The clock is a spin-off of NIST research on quantum computers, which grew out of earlier atomic clock research. Quantum computers, if they can be built, will be capable of solving certain types of complex problems that are impossible or prohibitively costly or time consuming to solve with today's technologies.

The NIST quantum logic clock uses two different kinds of ions, aluminum and beryllium, confined closely together in an electromagnetic trap and slowed by lasers to nearly "absolute zero" temperatures. Aluminum is a stable source of clock ticks, but its properties cannot be detected easily with lasers. The NIST scientists applied quantum computing methods to share information from the aluminum ion with the beryllium ion, a workhorse of their quantum computing research. The scientists can detect the aluminum clock's ticks by observing light signals from the beryllium ion.

NIST's tandem ion approach is unique among the world's atomic clocks and has a key advantage: "You can pick from a bigger selection of atoms," explains NIST physicist Jim Bergquist, who built the mercury clock. "And aluminum has a lot of good qualities-better than mercury's."

An optical clock can be evaluated precisely only by comparison to another clock of similar accuracy serving as a "ruler." NIST scientists used the quantum logic clock to measure the mercury clock, and vice versa. In addition, based on fluctuations in the frequencies of the two clocks relative to each other over time, NIST scientists were able to search for a possible change over time in a fundamental quantity called the fine-structure constant. This quantity measures the strength of electromagnetic interactions in many areas of physics, from studies of atoms and molecules to astronomy. Some evidence from astronomy has suggested the fine-structure constant may be changing very slowly over billions of years. If such changes are real, scientists would have to dramatically change their theories of the fundamental nature of the universe.

The NIST measurements indicate that the value of the fine-structure constant is not changing by more than 1.6 quadrillionths of 1 percent per year, with an uncertainty of 2.3 quadrillionths of 1 percent per year (a quadrillionth is a millionth of a billionth). The result is small enough to be "consistent with no change," according to the paper. However, it is still possible that the fine-structure constant is changing at a rate smaller than anyone can yet detect. The new NIST limit is approximately 10 times smaller than the best previous measurement of the possible present-day rate of change in the fine-structure constant. The mercury clock is an especially useful tool for such tests because its frequency fluctuations are magnified by any changes in this constant.

The work described in the new Science paper was supported in part by the Office of Naval Research and Disruptive Technology Office.

As a non-regulatory agency of the Commerce Department, NIST promotes U.S. innovation and industrial competitiveness by advancing measurement science, standards and technology in ways that enhance economic security and improve our quality of life.

*Journal reference: T. Rosenband, D.B. Hume, P.O. Schmidt, C.W. Chou, A. Brusch, L. Lorini, W.H. Oskay, R.E. Drullinger, T.M. Fortier, J.E. Stalnaker, S.A. Diddams, W.C. Swann, N.R. Newbury, W.M. Itano, D.J. Wineland, and J.C. Bergquist. 2008. Frequency ratio of Al+ and Hg+ single-ion optical clocks; metrology at the 17th decimal place. Science Express. Published online March 6.

Background: Where the 'Quantum Logic Clock' Gets Its Name

The NIST quantum logic clock is so named because it borrows techniques that are key to quantum computers, which would solve problems using quantum mechanics, nature's instruction book for the smallest particles of matter and light. Logic is reasoning that determines an action or result based on which one of different possible options is received as input. In the NIST clock, the input options are two different quantum states, or internal energy levels, of an aluminum ion. Information about this state is transferred to a beryllium ion, which, depending on the input, produces different signals that are easily detected.

NIST scientists use lasers to cool the two ions which are held 4 thousandths of a millimeter apart in an electromagnetic trap. Aluminum is the larger of the two ions, while the beryllium emits light under the conditions of this experiment. Scientists hit the ions with pulses from a "clock laser" within a narrow frequency range. If the laser frequency is at the center of the frequency range, the precise "resonance frequency" of aluminum, this ion jumps to a higher energy level, or 1 in the binary language of computers. Otherwise, the ion remains in the lower energy state, or 0.

If there is no change in the aluminum ion, then another laser pulse causes both ions to begin rocking side to side in unison because of their physical proximity and the interaction of their electrical charges. An additional laser pulse converts this motion into a change in the internal energy level of the beryllium ion. This pulse reverses the direction of the ion's magnetic "spin," and the beryllium goes dark, a signal that the aluminum remained in the 0 state.

On the other hand, if the aluminum ion jumps to the higher energy level, then the additional laser pulses fail to stimulate a shared rocking motion and have no effect on the beryllium ion, which keeps emitting light. Scientists detect this light as a signal that the aluminum ion jumped from 0 to 1.

The goal is to tune the clock laser to the exact frequency that prompts the aluminum to jump from 0 to 1. The actual measurement of the ticking of the clock is provided not by the ions but rather by the clock laser's precisely tuned center frequency, which is measured with a "frequency comb," a tool for measuring very high optical frequencies, or colors of light.

Adapted from materials provided by National Institute of Standards and Technology.

Quantum Channel Between Earth And Space? Firing Photons Makes Advance In Space Communication

2008-04-11T13:24:00.000-07:00

ScienceDaily (Mar. 29, 2008) — For the first time, physicists have been able to identify individual returning photons after firing and reflecting them off of a space satellite in orbit almost 1,500 kilometres above the earth. The experiment has proven the possibility of constructing a quantum channel between Space and Earth.
Research in the New Journal of Physics, discusses the feasibility of building a completely secure channel for global communication, via satellites in space, all thanks to advances in quantum mechanics.

The research team, led by Paolo Villoresi and Cesare Barbieri from Padova University, Italy, has taken intricate steps to fire photons directly at the Japanese Ajisai Satellite. The researchers have been able to prove that the photons received back at the Matera ground-based station, in southern Italy, are the same as those originally emitted.

This news will be welcomed by communication companies, banks, and MI5-types worldwide as it paves the way for quantum-encrypted communication - the only form of communication that could ensure beyond any doubt that there are no eavesdroppers.

Until now, quantum-encrypted communication has only been proven possible at distances up to about 150 kilometres, either down optical fibres or via telescopes. When sent down optical fibres, photons are dissipated due to scattering and adsorption and, when using telescopes, photons are subject to interfering atmospheric conditions.

Anton Zeilinger, 2008 winner of the Institute of Physics’ premier award, the Newton Medal, was involved in the research. The team now believes that Space-to-Earth quantum communication is possible with available technology.

The scientists write, “We have achieved significant experimental results towards the realization of a quantum communication channel, as well as how to actually adapt an existing laser ranging facility for quantum communication.”

The team will now be furthering the research by making it possible to emit and receive quantum keys, uncrackable strings of 1s and 0s that enable quantum communication from an active sender in space. Very recently, the Italian Space Agency has funded the initial phase of this project.

The published version of the paper "Experimental verification of the feasibility of a quantum channel between Space and Earth" was published March 28, 2008 in the New Journal of Physics 10 033038. (http://www.iop.org/EJ/abstract/1367-2630/10/3/033038)

Adapted from materials provided by New Journal of Physics.

Future Of Computing: Carbon Nanotubes And Superconductors To Replace The Silicon Chip

2008-04-11T13:19:00.000-07:00

ScienceDaily (Mar. 30, 2008) — The future of computing is under the spotlight at the Institute of Physics' Condensed Matter and Materials Physics conference at the University of London, UK, on 26-28 March.

The end of the silicon chip

The silicon chip, which has supplied several decades' worth of remarkable increases in computing power and speed, looks unlikely to be capable of sustaining this pace for more than another decade -- in fact, in a plenary talk at the conference, Suman Datta of Pennsylvania State University, USA, gives the conventional silicon chip no longer than four years left to run.

As silicon computer circuitry gets ever smaller in the quest to pack more components into smaller areas on a chip, eventually the miniaturized electronic devices are undermined by fundamental physical limits. They start to become leaky, making them incapable of holding onto digital information. So if the steady increases in computing capability that we have come to take for granted are to continue, some new technology will have to take over from silicon.

Replacing the chip with carbon nanotubes

At the conference, researchers at Leeds University in the UK will report an important step towards one prospective replacement. Carbon nanotubes, discovered in 1991, are tubes of pure carbon just a few nanometres wide -- about the width of a typical protein molecule, and tens of thousands of times thinner than a human hair. Because they conduct electricity, they have been proposed as ready-made molecular-scale wires for making electronic circuitry.

Some nanotubes behave as semiconductors, like silicon; others carry electric currents like metal wires. Already, fundamental elements of computer circuits such as transistors have been made from individual carbon nanotubes.

But the problem is arranging nanotubes into circuit patterns. One particular difficulty is that they are typically made as mixtures of metallic and semiconducting tubes, whereas just one type or the other is needed for a specific component. These electrical properties depend on the precise arrangement of carbon atoms in the nanotube, but that's hard to determine for single tubes.

Bryan Hickey and his coworkers at Leeds have now developed a technique that will reveal an individual nanotube's structure (and thus its electrical properties), and then allow it to be placed in a position on a surface with an accuracy of about 100 nanometres, a fraction of the width of a human blood cell. The nanotubes are grown on a perforated ceramic grid, and tubes lying across the holes are examined in an electron microscope to deduce their atomic structures. Then the researchers use two needle-fine tips like tweezers to pick up a single tube under the microscope and put back down on another surface.

Chris Allen, one of the Leeds teams, says, "With this technique we can make carbon nanotube devices of a complexity that is not achievable by most other means."

Boosting computer power with superconductors

Two further talks at the meeting will describe an even more dramatic way to overcome the limitations of silicon computers. Hans Mooij of the Delft University of Technology in the Netherlands and Raymond Simmons of the National Institute of Standards and Technology in Boulder, Colorado, USA, will claim that superconductors -- materials that conduct electricity with zero electrical resistance -- can harness the power of quantum physics to boost computer power tremendously.

So-called quantum computers have become one of the hottest items in physics over the past decade. They attempt to improve on the power of silicon not by making components smaller but by exploiting the counterintuitive principles of quantum mechanics, the theory generally used to understand how objects behave at the scale of atoms and subatomic particles.

Objects governed by quantum theory can be in several different states at once, like a light switch being simultaneously 'on' and 'off'. These 'superposition' states don't correspond to anything familiar from our everyday world, but countless experiments have proved that they can exist so long as the quantum objects are not disturbed by, for example, making a measurement on them.

In a quantum computer, the equivalent of 'bits' that hold binary information as 1's and 0's in today's computers will be quantum bits or qubits, which can also exist as superpositions of 1's and 0's. This massively increases the amount of information that can be encoded in a quantum computer's memory. The catch is that superpositions are extremely delicate and hard to maintain, especially in memories containing large numbers of qubits that interact with one another.

Various candidates for making qubits are being explored, such as magnetically trapped atoms or nanometre-scale blobs of semiconductors. But it has long been recognized that loops of superconducting material can also be placed in quantum superposition states, and thus act as qubits. Here the quantum states may correspond to an electric current circulating round the ring in one direction or the other. (In superconductors this circulation can continue more or less indefinitely without petering out, because there is no electrical resistance.)

At the conference, Simmonds will describe the first demonstration of information being transmitted between two such superconducting qubits. This shows that elements of this kind can act as a quantum-computing memory and a "bus" for qubits to communicate with one another, an essential requirement of any working computer.

The two superconducting loops are made from thin wires of aluminium laid down on a slice of sapphire and cooled to less than 0.1 degrees of absolute zero to make them superconducting. They sit just a millimetre apart, but are connected by a meandering waveguide 7 mm long -- a kind of light channel, like an optical fibre, but for microwaves. The superposition state of one qubit can be transferred into a microwave electrical vibration of the waveguide, like plucking a guitar string. This microwave "photon" of energy recording the first qubit's state can then be controllably transferred to the other qubit -- crucially, without destroying these delicate quantum states.

Mooij was part of a group that first demonstrated in 2000 that such superconducting loops can be placed in quantum superposition states. He will describe the progress that he and others have made since then, both in making practical quantum devices and in using them to explore fundamental aspects of quantum mechanics, such as whether and how the 'quantum weirdness' of superpositions can survive when the objects concerned get much larger than atoms.

Mooij says that one of the biggest challenges in making quantum computers this way is to progress from two to three qubits that communicate with each other. He says that the particular approach he and his colleagues have been developing has the advantage that, if this can be achieved, scaling up further won't be too difficult.

Mooij says, "With our qubit, once we have three set up we can move on to twenty or fifty."

Adapted from materials provided by Institute of Physics, via EurekAlert!, a service of AAAS.

Expert Foresees 10 More Years Of Research & Development To Make Solar Energy Competitive

2008-04-11T13:14:00.000-07:00

ScienceDaily (Apr. 11, 2008) — Despite oil prices that hover around $100 a barrel, it may take at least 10 or more years of intensive research and development to reduce the cost of solar energy to levels competitive with petroleum, according to an authority on the topic.
"Solar can potentially provide all the electricity and fuel we need to power the planet," Harry Gray, Ph.D., scheduled to speak here today at the 235th national meeting of the American Chemical Society (ACS). His presentation, "Powering the Planet with Solar Energy," is part of a special symposium arranged by Bruce Bursten, Ph.D., president of the ACS, the world's largest scientific society celebrating the 10th anniversary of the Beckman Scholars Program.

"The Holy Grail of solar research is to use sunlight efficiently and directly to "split" water into its elemental constituents -- hydrogen and oxygen -- and then use the hydrogen as a clean fuel," Gray said.

Gray is the Arnold O. Beckman Professor of Chemistry and Founding Director of the Beckman Institute at the California Institute of Technology. He is the principal investigator in an NSF funded Phase I Chemical Bonding Center (CBC) -- a Caltech/MIT collaboration -- and a principal investigator at the Caltech Center for Sustainable Energy Research (CCSER).

This research has the goal of transforming the industrialized world from one powered by fossil fuels to one powered by sunlight. The CBC research focuses on converting sunlight to chemical fuels while research in the CCSER focuses on generating electricity from sunlight and developing fuel cells.

In his talk at the ACS Presidential Symposium, Gray cited the vast potential of solar energy, noting that more energy from sunlight strikes the Earth in one hour than all of the energy consumed on the planet in one year.

The single biggest challenge, Gray said, is reducing costs so that a large-scale shift away from coal, natural gas and other non-renewable sources of electricity makes economic sense. Gray estimated the average cost of photovoltaic energy at 35 to 50 cents per kilowatt-hour. By comparison, other sources are considerably less expensive, with coal and natural gas hovering around 5-6 cents per kilowatt-hour.

Because of its other advantages -- being clean and renewable, for instance -- solar energy need not match the cost of conventional energy sources, Gray indicated. The breakthrough for solar energy probably will come when scientists reduce the costs of photovoltaic energy to about 10 cents per kilowatt-hour, he added. "Once it reaches that level, large numbers of consumers will start to buy in, driving the per-kilowatt price down even further. I believe we are at least ten years away from photovoltaics being competitive with more traditional forms of energy."

Major challenges include developing cheap solar cells that work without deterioration and reducing the amounts of toxic materials used in the manufacture of these cells. But producing low cost photovoltaics is only a step in the right direction. Chemists also need to focus on the generation of clean fuels at costs that can compete with oil and coal.

Gray emphasized this point: "The pressure is on chemists to make hydrogen from something other than natural gas or coal. We've got to start making it from sunlight and water."

Gray noted that the NSF CBC program currently includes Caltech and MIT, but would expand in a second phase to include several additional institutions.

Adapted from materials provided by American Chemical Society, via EurekAlert!, a service of AAAS.

New Material Shows Great Promise For Nuclear Waste Clean-Up

2008-04-11T13:08:00.000-07:00

ScienceDaily (Mar. 5, 2008) — Nuclear power has advantages, but, if this method of making power is to be viable long term, discovering new solutions to radioactive waste disposal and other problems are critical. Otherwise nuclear power is unlikely to become mainstream.
A team of Northwestern University chemists is the first to focus on metal sulfide materials as a possible source for nuclear waste remediation methods. Their new material is extremely successful in removing strontium from a sodium-heavy solution, which has concentrations similar to those in real liquid nuclear waste. Strontium-90, a major waste component, is one of the more dangerous radioactive fission materials created within a nuclear reactor.

By taking advantage of ion exchange, the new method captures and concentrates strontium as a solid material, leaving clean liquid behind. In the case of actual nuclear waste remediation, the radioactive solid could then be dealt with separately -- handled, moved, stored or recycled -- and the liquid disposed.

"It is a very difficult job to capture strontium in vast amounts of liquid nuclear waste," said Mercouri G. Kanatzidis, Charles E. and Emma H. Morrison Professor of Chemistry in the Weinberg College of Arts and Sciences and the paper's senior author.* "Sodium and calcium ions, which are nonradioactive, are present in such enormous amounts compared to strontium that they can be captured instead of the radioactive material, interfering with remediation."

Strontium is like a needle in a haystack: sodium ions outnumber strontium ions by more than a million to one. The material developed at Northwestern -- a layered metal sulfide made of potassium, manganese, tin and sulfur called KMS-1 -- attracts strontium but not sodium.

"The metal sulfide did much, much better than we expected at removing strontium in such an excess of sodium," said Kanatzidis. "We were really amazed at how well it discriminates against sodium and think we have something special. As far as we can tell, this is the best material out there for this kind of application."

KMS-1 works at the extremes of the pH scale -- in very basic and very acidic solutions, the conditions common in nuclear waste -- and everywhere in between. Metal oxides and polymer resins, the materials currently used in nuclear waste remediation, perform reasonably well but are more limited than KMS-1: each typically works in either basic or acidic conditions but not both and definitely not across the pH scale.

In earlier work, Kanatzidis and his team had found KMS-1 to be very quick and facile at ion exchange. (The material gives up an ion and takes another to maintain charge balance.) Knowing this and also that the ion exchange process is a removal process, the researchers decided that strontium was an interesting ion with which to test their new material.

The solution the researchers used in the lab contained strontium and two "interfering" ions, sodium and calcium, in concentrations like those found in the nuclear waste industry. (Nonradioactive strontium, which works the same as the radioactive version, was used in the experiments.) KMS-1, a free flowing black-brown powder, was packaged like tea in a teabag and then dropped into the solution. The all-important ion exchange followed: the metal sulfide "teabag" soaked up the strontium and gave off potassium, which is not radioactive, into the liquid.

KMS-1 does its remarkable work targeting only strontium by taking advantage of two things: strontium is a heavier ion than calcium, and sulfur (a component of KMS-1) attracts heavier ions; and KMS-1 attracts ions with more charge so it attracts strontium, which has a charge of 2+, and doesn't attract sodium, which only has a charge of 1+. So, as Kanatzidis likes to say, "Our material beats both sodium and calcium."

"The nuclear power process generates enormous amounts of radioactive liquid waste, which is stored in large tanks," said Kanatzidis. "If we can concentrate the radioactive material, it can be dealt with and the nonradioactive water thrown away. I can imagine our material as part of a cleansing filter that the solution is passed through."

Looking to the future, to be a scaleable and affordable remediation method, the metal in the metal sulfide needs to be inexpensive and readily available and also make a stable compound.

"We focused on potassium, manganese and tin because we have been working with them for some time," said Manolis J. Manos, a postdoctoral fellow at Northwestern and lead author of the paper. "All three metals make stable compounds and are common and abundant."

"Our next step is to do systematic studies, including using an actual waste solution from the nuclear power industry, to learn how KMS-1 works and how to make even better metal sulfides," added Manos.

The results will be published online the week of March 3 in the Proceedings of the National Academy of Sciences. In addition to Kanatzidis and Manos, Nan Ding, a former graduate student in Kanatzidis' group, now at Claflin College in South Carolina, is the other author of the PNAS paper, titled "Layered Metal Sulfides: Exceptionally Selective Agents for Radioactive Strontium Removal."

Adapted from materials provided by Northwestern University, via EurekAlert!, a service of AAAS.

Field Strength And Density Of Fusion Implosions Aid Quest For Fusion Energy

2008-04-11T13:00:00.000-07:00

ScienceDaily (Mar. 3, 2008) — Scientists have identified for the first time two distinctly different types of electromagnetic configurations in inertial confinement fusion implosions that have substantial effects on implosion dynamics and diagnosis.
The work could one day help scientists harness nuclear fusion as an energy source. It could also shed light on basic questions about the physics of stars.

Nuclear fusion -- the process by which atomic particles clump together to form a heavier nucleus -- releases an enormous amount of energy (roughly one million times that of a chemical reaction). When nuclear fusion occurs in an uncontrolled chain reaction, it can result in a thermonuclear blast--such as the one generated by hydrogen bombs.

Achieving controlled nuclear fusion, which could be a safe and reliable source of nearly limitless energy, is one of the "holy grails" of high-energy-density physics, according to Richard Petrasso, senior research scientist at MIT's Plasma Science and Fusion Center and an author of a new paper in the journal Science.

In the most recent research, which appears in the Feb. 29 issue of the journal, Science, Ryan Rygg of Lawrence Livermore National Laboratory and colleagues from the Massachusetts Institute of Technology and the University of Rochester used radiography with a pulsed monoenergetic proton source to simultaneously measure field strength and area densities by looking at the energy lost by protons during the implosion.

Inertial confinement fusion (ICF) is a process where nuclear fusion reactions (which release copious amounts of energy) are initiated by heating and compressing a fuel target, typically in the form of a spherical shell containing a mixture of deuterium and tritium. Upon completion of the National Ignition Facility laser, fuel will be compressed a thousand-fold by rapid energy deposition onto the surface of a fuel target.

At the OMEGA laser in Rochester, the team blasted 36 laser beams that deposited 14 kilojoules of energy in a one nano-second pulse into ICF fast-ignition capsules. (A nanosecond is one billionth of a second). To observe the dynamics of the imploding capsules, Rygg radiographed the targets before and during implosion. Radiography typically uses X-rays to view unseen or hard-to-image objects, but radiography using protons is sensitive to different phenomena.

The radiographic images showed the presence of complex, filamentary magnetic fields, which permeate the field of view, while a coherent centrally directed electric field is seen near the capsule shell, which had imploded to half its initial radius.

"By measuring the evolution of this coherent electric field, we could potentially map capsule pressure dynamics throughout the implosion, which would be invaluable in assessing implosion performance," Rygg said. "The striated fields may provide a snapshot of structures originally produced inside the critical surface at various times during the implosion, which would open the door for evaluating the entire implosion process."

This work was performed while Rygg was a postdoc at MIT.

Adapted from materials provided by DOE/Lawrence Livermore National Laboratory.

Most Powerful Laser In The World Fires Up

2008-04-11T12:52:00.000-07:00

ScienceDaily (Apr. 9, 2008) — The Texas Petawatt laser reached greater than one petawatt of laser power on Monday morning, March 31, making it the highest powered laser in the world, Todd Ditmire, a physicist at The University of Texas at Austin, said. The Texas Petawatt is the only operating petawatt laser in the United States.
Ditmire says that when the laser is turned on, it has the power output of more than 2,000 times the output of all power plants in the United States. (A petawatt is one quadrillion watts.) The laser is brighter than sunlight on the surface of the sun, but it only lasts for an instant, a 10th of a trillionth of a second (0.0000000000001 second).

Ditmire and his colleagues at the Texas Center for High-Intensity Laser Science will use the laser to create and study matter at some of the most extreme conditions in the universe, including gases at temperatures greater than those in the sun and solids at pressures of many billions of atmospheres.

This will allow them to explore many astronomical phenomena in miniature. They will create mini-supernovas, tabletop stars and very high-density plasmas that mimic exotic stellar objects known as brown dwarfs.

"We can learn about these large astronomical objects from tiny reactions in the lab because of the similarity of the mathematical equations that describe the events," said Ditmire, director of the center.

Such a powerful laser will also allow them to study advanced ideas for creating energy by controlled fusion.

The Texas Petawatt was built with funding provided by the National Nuclear Security Administration, an agency within the U. S. Department of Energy.

Adapted from materials provided by University of Texas at Austin.

New Breed Of Cognitive Robot Is A Lot Like A Puppy

2008-04-11T12:45:00.000-07:00

ScienceDaily (Mar. 31, 2008) — Designers of artificial cognitive systems have tended to adopt one of two approaches to building robots that can think for themselves: classical rule-based artificial intelligence or artificial neural networks. Both have advantages and disadvantages, and combining the two offers the best of both worlds, say a team of European researchers who have developed a new breed of cognitive, learning robot that goes beyond the state of the art.
The researchers’ work brings together the two distinct but mutually supportive technologies that have been used to develop artificial cognitive systems (ACS) for different purposes. The classical approach to artificial intelligence (AI) relies on a rule-based system in which the designer largely supplies the knowledge and scene representations, making the robot follow a decision-making process – much like climbing through the branches of a tree – toward a predefined response.

Biologically inspired artificial neural networks (ANNs), on the other hand, rely on processing continuous signals and a non-linear optimisation process to reach a response which, due to the lack of preset rules, requires developers to carefully balance the system constraints and its freedom to act autonomously.

“Developing systems in classical AI is essentially a top-down approach, whereas in ANN it is a bottom-up approach,” explains Michael Felsberg, a researcher at the Computer Vision Laboratory of Linköping University in Sweden. “The problem is that, used individually, these systems have major shortcomings when it comes to developing advanced ACS architectures. ANN is too trivial to solve complex tasks, while classical AI cannot solve them if it has not been pre-programmed to do so.”

Beyond the state of the art

Working in the EU-funded COSPAL project, Felsberg’s team found that using the two technologies together solves many of those issues. In what the researchers believe to be the most advanced example of such a system developed anywhere in the world, they used ANN to handle the low-level functions based on the visual input their robots received and then employed classical AI on top of that in a supervisory function.

“In this way, we found it was possible for the robots to explore the world around them through direct interaction, create ways to act in it and then control their actions in accordance. This combines the advantages of classical AI, which is superior when it comes to functions akin to human rationality, and the advantages of ANN, which is superior at performing tasks for which humans would use their subconscious, things like basic motor skills and low-level cognitive tasks,” notes Felsberg.

The most important difference between the COSPAL approach and what had been the state of the art is that the researchers’ ACS is scalable. It is able to learn by itself and can solve increasingly complex tasks with no additional programming.

“There is a direct mapping from the visual precepts to performing the action,” Felsberg confirms. “With previous systems, if something in the environment changed that the low-level system was not programmed to recognise, it would give random responses but the supervising AI process would not realise anything was wrong. With our approach, the system realises something is different and if its actions do not result in success it tries something else,” the project coordinator explains.

“Like training a child or a puppy”

This trial-and-error learning approach was tested by making the COSPAL robot complete a shape-sorting puzzle, but without telling it what it had to do. As it tried to fit pegs into holes it gradually learnt what would fit where, allowing it to complete the puzzle more quickly and accurately each time.

“After visual bootstrapping, the only human input was from an operator who had two buttons, one to tell the robot it was successful and another to tell it that it had made a mistake. It is much like training a child or a puppy,” Felsberg says.

Though a learning, cognitive robot of the kind developed in COSPAL constitutes an important leap forward toward the development of more autonomous robots, Felsberg says it will be some time before robots gain anything close to human cognition and intelligence, if they ever do.

“In human terms, our robot is probably like a two or three year old child, and it will take a long time for the technology to progress into the equivalent of adulthood. I don’t think we will see it in our lifetimes,” he says.

Nonetheless, robots like those developed in COSPAL will undoubtedly start to play a greater role in our lives. The project partners are in the process of launching a follow-up project called DIPLECS to test their ACS architecture in a car. It will be used to make the vehicle cognitive and aware of its surroundings, creating an artificial co-pilot to increase safety no matter the weather, road or traffic conditions.

“In the real world you need a system that is capable of adapting to unforeseen circumstances, and that is the greatest accomplishment of our ACS,” Felsberg notes.

Adapted from materials provided by ICT Results.

Soccer Robots Compete For The Title

2008-04-11T12:41:00.000-07:00

ScienceDaily (Apr. 4, 2008) — Robot soccer is an ambitious high-tech competition for universities, research institutes and industry. Several major tournaments are planned for 2008, the biggest of which is the ‘RoboCup German Open’. From April 21-25, over 80 teams of researchers from more than 15 countries are expected to face off at the Hannover Messe. In a series of soccer matches in several leagues, they will be putting the latest technologies on display.
For a machine, a soccer match is a highly complex endeavor. Robots must be able to reliably recognize the ball, the sidelines and the goalposts in addition to distinguishing between their teammates and opponents. To this end, they are outfitted with all sorts of high-tech equipment: cameras and sensors scan the robots’ surroundings, internal processors convert data to define game tactics and defense strategies, and innovative engines allow the automated players to sprint across the field and unexpectedly fake out their opponents.

There are now nine leagues, each of which has its own technological focus. In the middle-size league, robots get around on wheels. Four players and a goalkeeper compete for each team on a 20 x 14-meter pitch with standard soccer goals. They must be able to function completely independently and are equipped with internal camera systems that process information in real time. What’s more, the robots can move up to two meters per second.

Other automated soccer players, such as Sony’s robotic dog Aibo, run on four mechanical paws. And two-legged robots have been competing against each other at the RoboCup since 2005. “These humanoid robots have come a long way in recent years,” says Dr. Ansgar Bredenfeld, who is in charge of the RoboCup at IAIS. “Just like real players, they fall down and get up again, go after the ball autonomously and score goals.”

The RoboCup is more than just a soccer tournament. Since 2006, there has been a ‘RoboCup(at)Home’ category, a competition for service robots. In a replicated room, the robots must access refrigerators, collect garbage and recognize people. And in the ‘RoboCup-Rescue’ category, rescue robots must complete an obstacle course.

“RoboCup stimulates technological development in a way that wouldn’t otherwise be possible,” says Professor Stefan Wrobel, Executive Director of IAIS. “Many components that were originally designed for robot soccer have since made their way into other applications, for instance in localization technology for inspection robots.” Robots that can mow the lawn on their own or collect samples from the ocean floor for marine researchers are also equipped with RoboCup technology.

Participants under 20 years of age have their own competition, ‘RoboCupJunior’, which runs at the same time as the ‘RoboCupSenior’ tournament. In addition to fighting it out in a robot soccer tournament, the future generation of scientists will be competing in the RoboDance (robot dancing) and RoboRescue (obstacle course) competitions. These events are extremely popular: about 300 teams have registered for this year’s competition. To participate in Hannover, teams must qualify at one of three tournaments. “Germany has a serious problem: it lacks tens of thousands of engineers,” Wrobel points out. “RoboCupJunior is a very important event, as it sparks young people’s interest in technical degree courses.”

The tournament is being organized and carried out by the Fraunhofer Institute for Intelligent Analysis and Information Systems IAIS in Sankt Augustin.

Adapted from materials provided by Fraunhofer-Gesellschaft.

New Laboratory Robot Can Lift The Burden Of Boring Work

2008-04-11T12:38:00.000-07:00

ScienceDaily (Jan. 8, 2008) — Assistant robots really suited for everyday routines, which take over burdensome or monotonous work for humans, are still virtually unavailable commercially. Such systems are usually either not absolutely safe or not cost effective. The laboratory robot LISA could change that.
We have been hearing and reading for a long time about assistant robots that silently and carefully zip around humans to liberate them from burdensome work. Nevertheless, a truly convincing high-tech assistant with a gripper arm is not yet commercially available. LISA – short for life science assistant – is intended to change that. In roughly one year, a prototype of this robot will be rolling through biotechnology labs, loading incubators and measuring equipment with sample trays in concert with human colleagues and accurately navigating from one lab instrument to the next.

The developers from the Fraunhofer Institute for Factory Operation and Automation IFF in Magdeburg have especially made sure that their silent assistant is safe and injures no one. Only then will the German institutions for statutory accident insurance and prevention and TÜV give it their blessing for everyday use.

LISA is equipped with a sensing gripper arm designed to hold plastic dishes but not injure human beings. Its “artificial skin” consists of conductive foam and textiles and intelligent signal processing electronics. This skin immediately senses and cushions inadvertent jostling. A thermographic camera additionally registers body heat and indicates for instance if a human colleague’s hand is in the way.

The developers at the IFF and their seven project partners from industry and research aim to construct a robot suited for everyday routines that can already be cost effectively deployed shortly after the pilot phase – and around the clock at that. Hence, LISA was not overloaded with functionalities. It has a laser-aided navigation system with which it orients itself in familiar spaces and goes through doorways on its own. It safely navigates around obstacles and people. That suffices for everyday laboratory work anytime.

LISA uses language to communicate and, thanks to its large vocabulary, understands entire sentences like “Get me dish A4 from incubator 8.” If something is unclear, it asks. Additionally, simple work commands can be entered through a touchscreen. LISA was conceived to be able to learn new actions easily. This is particularly important for life science laboratories in which new types of measuring stations are frequently installed or varied work steps are executed. “LISA was tailored precisely to its niche for use,” says project coordinator Dr. Norbert Elkmann from the IFF. “This is the only way its everyday use will soon be possible – we could be that far in about one to two years.”

Adapted from materials provided by Fraunhofer-Gesellschaft.

Gut Reaction: Cow Stomach Holds Key To Turning Corn Into Biofuel

2008-04-11T12:31:00.000-07:00

ScienceDaily (Apr. 10, 2008) — An enzyme from a microbe that lives inside a cow's stomach is the key to turning corn plants into fuel, according to Michigan State University scientists.
The enzyme that allows a cow to digest grasses and other plant fibers can be used to turn other plant fibers into simple sugars. These simple sugars can be used to produce ethanol to power cars and trucks.

MSU scientists have discovered a way to grow corn plants that contain this enzyme. They have inserted a gene from a bacterium that lives in a cow's stomach into a corn plant. Now, the sugars locked up in the plant's leaves and stalk can be converted into usable sugar without expensive synthetic chemicals.

"The fact that we can take a gene that makes an enzyme in the stomach of a cow and put it into a plant cell means that we can convert what was junk before into biofuel," said Mariam Sticklen, MSU professor of crop and soil science. She is presenting at the 235th national American Chemical Society meeting in New Orleans April 9. The work also is presented in the "Plant Genetic Engineering for Biofuel Production: Towards Affordable Cellulosic Ethanol" in the June edition of Nature Review Genetics.

Cows, with help from bacteria, convert plant fibers, called cellulose, into energy, but this is a big step for biofuel production. Traditionally in the commercial biofuel industry, only the kernels of corn plants could be used to make ethanol, but this new discovery will allow the entire corn plant to be used -- so more fuel can be produced with less cost.

Turning plant fibers into sugar requires three enzymes. The new variety of corn created for biofuel production, called Spartan Corn III, builds on Sticklen's earlier corn versions by containing all three necessary enzymes.

The first version, released in 2007, cuts the cellulose into large pieces with an enzyme that came from a microbe that lives in hot spring water.

Spartan Corn II, with a gene from a naturally occurring fungus, takes the large cellulose pieces created by the first enzyme and breaks them into sugar pairs.

Spartan Corn III, with the gene from a microbe in a cow, produces an enzyme that separates pairs of sugar molecules into simple sugars. These single sugars are readily fermentable into ethanol, meaning that when the cellulose is in simple sugars, it can be fermented to make ethanol.

"It will save money in ethanol production," Sticklen said. "Without it they can't convert the waste into ethanol without buying enzymes -- which is expensive."

The Spartan Corn line was created by inserting an animal stomach microbe gene into a plant cell. The DNA assembly of the animal stomach microbe required heavy modification in the lab to make it work well in the corn cells. Sticklen compared the process to adding a single Christmas tree light to a tree covered in lights.

"You have a lot of wiring, switches and even zoning," Sticklen said. "There are a lot of changes. We have to increase production levels and even put it in the right place in the cell."

If the cell produced the enzyme in the wrong place, then the plant cell would not be able to function, and, instead, it would digest itself. That is why Sticklen found a specific place to insert the enzyme.

One of the targets for the enzyme produced in Spartan Corn III is a special part of the plant cell, called the vacuole. The vacuole is a safe place to store the enzyme until the plant is harvested. The enzyme will collect in the vacuole with other cellular waste products

Because it is only in the vacuole of the green tissues of plant cells, the enzyme is only produced in the leaves and stalks of the plant, not in the seeds, roots or the pollen. It is only active when it is being used for biofuels because of being stored in the vacuole

"Spartan Corn III is one step ahead for science, technology, and it is even a step politically," Sticklen said. "It is one step closer to producing fuel in our own country."

Sticklen's research was funded by MSU and the Consortium for Plant Biotechnology Research.

A graphic illustrating the process is available at http://special.newsroom.msu.edu/newsroom_docs/spartancorn3v8.pdf.

Adapted from materials provided by Michigan State University.

Visualizing The Machinery Of mRNA Splicing

2008-04-11T12:26:00.000-07:00

ScienceDaily (Apr. 8, 2008) — Recent research at Yale provided a glimpse of the ancient mechanism that helped diversify our genomes; it illuminated a relationship between gene processing in humans and the most primitive organisms by creating the first crystal structure of a crucial self-splicing region of RNA.
Genes of higher organisms code for production of proteins through intermediary RNA molecules. But, after transcription from the DNA, these RNAs must be cut into pieces and patched together before they are ready for translation into protein. Stretches of the RNA sequence that code for protein are kept, and the intervening sequences, or introns, are spliced out of the transcript.

This work, published in Science, highlights a 16-year quest by Anna Marie Pyle, the William Edward Gilbert Professor of Molecular Biophysics & Biochemistry at Yale, and her research team into the nature of "group II" introns, a particular type of intron within gene transcripts that catalyzes its own removal during the maturation of RNA.

Group II introns are found throughout nature, in all forms of living organisms. Although much has been learned about their structure and how they work through biochemical and computational analysis, until now there have been no high-resolution crystal structures available. The resulting images have provided both confirmation of the earlier work and new information on the three-dimensional structure of RNA and the mechanism of splicing.

"One of the most exciting aspects of this work was that we did not need to do anything disruptive to these molecules to prepare them for structural analysis," said Pyle. "The molecules showed us their structure, their active site and their activity -- all in a natural state. We were even able to visualize their associated ions."

According to Pyle, the crystal structure revealed some unexpected features -- showing two sections that were most implicated as key elements of the active site and strengthening a theory that the process of splicing in humans "shares a close evolutionary heritage" with ancient forms of bacteria.

Looking to future applications of the work, Pyle said, "Group II introns hold promise in the future as agents of gene therapy. A free intron is an infectious element that is special because it targets DNA sites very specifically. We hope that further knowledge of these structures may lead to the development of new genetic tools and therapeutics."

Other authors on the paper are Navtej Toor, Kevin S. Keating and Sean D. Taylor at Yale. Professor Pyle is also an Investigator of the Howard Hughes Medical Institute. Funding for the research was from the Howard Hughes Medical Institute, the National Institutes of Health, the Department of Defense and the National Science Foundation.

Journal reference: Science 320 , 77-82 (April 4, 2008). [DOI: 10.1126/science.1153803]

Adapted from materials provided by Yale University.

Scientists Find A Fingerprint Of Evolution Across The Human Genome

2008-04-11T12:16:00.000-07:00

ScienceDaily (Apr. 9, 2008) — The Human Genome Project revealed that only a small fraction of the 3 billion “letter” DNA code actually instructs cells to manufacture proteins, the workhorses of most life processes. This has raised the question of what the remaining part of the human genome does. How much of the rest performs other biological functions, and how much is merely residue of prior genetic events?...
Scientists from Cold Spring Harbor Laboratory (CSHL) and the University of Chicago now report that one of the steps in turning genetic information into proteins leaves genetic fingerprints, even on regions of the DNA that are not involved in coding for the final protein. They estimate that such fingerprints affect at least a third of the genome, suggesting that while most DNA does not code for proteins, much of it is nonetheless biologically important – important enough, that is, to persist during evolution.

Conservation of genetic information

To gauge how critical a particular stretch of DNA is, biologists often look at the detailed sequence of “letters” it consists of, and compare it with a corresponding stretch in related creatures like mice. If the stretch serves no purpose, the thinking goes, the two sequences will differ because of numerous mutations since the two species last shared an ancestor. In contrast, it’s believed that the sequences of important genes will be similar, or “conserved,” in different species, because animals with mutations in these genes did not survive. Biologists therefore regard conserved sequences as a sign of biological importance.

To test for conservation, researchers need to find matching stretches in the two species. This is relatively easy for stretches that “code” for proteins, where scientists long ago learned the meaning of the sequence. For “noncoding” regions, however, the comparison is often ambiguous. Even within a gene, stretches of DNA that code for pieces of the target protein are usually interspersed with much larger noncoding stretches, called introns, that are removed from the RNA working copy of the DNA before the protein is made.

Signs of splicing

Previous researchers assumed that mutations in the middle of introns do not affect the final protein, so they simply accumulate. In the new work, however, the researchers found signs that evolution rejects some types of mutations even in these regions of the genome. Although the selection is weak, “introns are not neutral,” in their effect on survival, says CSHL professor Michael Zhang, a bioinformatics expert who headed the research team.

To look for selection, CSHL researcher Chaolin Zhang, a doctoral candidate at Stony Brook University, looked in the human genome for a subtle statistical imbalance in how often various “letters” appear. The researchers attribute this imbalance to special short stretches of DNA that mark regions to be removed. Unless these signal sequences are sprinkled throughout an intron, the data suggest, it may not be properly spliced out, with potentially fatal consequences. Other sequences must likewise be preserved in the regions to be retained.

The scientists found a preference for some “letters” across intron regions, and the opposite preference in coding regions. Together, these regions make up at least a third of the genome, which is thus under selective pressure during evolution. The result supports other recent studies that suggest that, although most DNA does not code for proteins, much of it is nonetheless biologically important.

In addition to demonstrating how splicing affects genetic evolution, the statistical analysis identified possible signaling sequences, some that were already known and others that are new. According to co-author Adrian Krainer, a CSHL professor and splicing expert, “the exciting thing will be to experimentally test whether these predicted elements are really true.”

The article “RNA landscape of evolution for optimal exon and intron discrimination,” authored by Chaolin Zhang, Wen-Hsiung Li, Adrian R. Krainer, and Michael Q. Zhang, appears in the April 15, 2008 edition of the Proceedings of the National Academy of Sciences.

Adapted from materials provided by Cold Spring Harbor Laboratory.

Carbon Nanotubes Made Into Conductive, Flexible 'Stained Glass'

2008-04-11T12:11:00.001-07:00

ScienceDaily (Apr. 10, 2008) — Carbon nanotubes are promising materials for many high-technology applications due to their exceptional mechanical, thermal, chemical, optical and electrical properties.
Now researchers at Northwestern University have used metallic nanotubes to make thin films that are semitransparent, highly conductive, flexible and come in a variety of colors, with an appearance similar to stained glass. These results, published online in the journal Nano Letters, could lead to improved high-tech products such as flat-panel displays and solar cells.

The diverse and exemplary properties of carbon nanotubes have inspired a vast range of proposed applications including transistors, logic gates, interconnects, conductive films, field emission sources, infrared emitters, biosensors, scanning probes, nanomechanical devices, mechanical reinforcements, hydrogen storage elements and catalytic supports.

Among these applications, transparent conductive films based on carbon nanotubes have attracted significant attention recently. Transparent conductors are materials that are optically transparent, yet electrically conductive. These materials are commonly utilized as electrodes in flat-panel displays, touch screens, solid-state lighting and solar cells. With pressure for energy-efficient devices and alternative energy sources increasing, the worldwide demand for transparent conductive films also is rapidly increasing.

Indium tin oxide currently is the dominant material for transparent conductive applications. However, the relative scarcity of indium coupled with growing demand has led to substantial cost increases in the past five years. In addition to this economic issue, indium tin oxide suffers from limited optical tunability and poor mechanical flexibility, which compromises its use in applications such as organic light-emitting diodes and organic photovoltaic devices.

The Northwestern team has taken an important step toward identifying an alternative transparent conductor. Utilizing a technique known as density gradient ultracentrifugation, the researchers have produced carbon nanotubes with uniform electrical and optical properties. Thin films formulated from these high purity carbon nanotubes possess 10-fold improvements in conductivity compared to pre-existing carbon nanotube materials.

In addition, density gradient ultracentrifugation allows carbon nanotubes to be sorted by their optical properties, enabling the formation of semitransparent conductive films of a given color. The resulting films thus have the appearance of stained glass. However, unlike stained glass, these carbon nanotube thin films possess high electrical conductivity and mechanical flexibility. The latter property overcomes one of the major limitations of indium tin oxide in flexible electronic and photovoltaic applications.

"Transparent conductors have become ubiquitous in modern society -- from computer monitors to cell phone displays to flat-panel televisions," said Mark Hersam, professor of materials science and engineering in Northwestern's McCormick School of Engineering and Applied Science and professor of chemistry in the Weinberg College of Arts and Sciences, who led the research team.

"High purity carbon nanotube thin films not only have the potential to make inroads into current applications but also accelerate the development of emerging technologies such as organic light-emitting diodes and organic photovoltaic devices. These energy-efficient and alternative energy technologies are expected to be of increasing importance in the foreseeable future."

In addition to Hersam, the other author of the Nano Letters paper is Alexander Green, a graduate student in materials science and engineering at Northwestern.

Adapted from materials provided by Northwestern University, via EurekAlert!, a service of AAAS.

Sweet Nanotech Batteries: Nanotechnology Could Solve Lithium Battery Charging Problems

2008-04-11T12:05:00.000-07:00

ScienceDaily (Apr. 10, 2008) — Nanotechnology could improve the life of the lithium batteries used in portable devices, including laptop computers, mp3 players, and mobile phones. Research to be published in the Inderscience publication International Journal of Nanomanufacturing demonstrates that carbon nanotubes can prevent such batteries from losing their charge capacity over time.
Researchers at the Shenyang National Laboratory for Materials Science, in China, have been investigating how to improve the kind of rechargeable batteries that are almost ubiquitous in today's portable devices. Mobile phones, mp3 players, personal digital assistants (PDAs), and laptop computers usually use lithium-ion batteries to give them portability. However, Li-ion batteries suffer from degradation especially when they get too hot or too cold and eventually lose the capacity to be fully recharged. This means a loss of talk time for mobile phone users and often no chance to use a laptop for the whole of a long haul flight.

The problem of the slow degradation of Li-ion batteries is usually due to the formation of a solid electrolyte interphase film that increase the batteries internal resistance and prevents a full recharge. Researchers have suggested using silicon in the composition of the negative electrode material in Li-ion batteries to improve charge capacity. However, this material leads to even faster capacity loss as it repeatedly alloys and then de-alloys during charge-discharge cycles.

Shengyang's Hui-Ming Cheng and colleagues have turned to carbon nanotubes (CNTs) to help them use silicon (Si) as the battery anode but avoid the problem of large volume change during alloying and de-alloying. Carbon nanotubes resemble rolled-up sheets of hexagonal chicken wire with a carbon atom at the crossover points of the wires and the wires themselves being the bonds between carbon atoms, and they can be up to a millimeter long but mere nanometers in diameter.

The researchers grew carbon nanotubes on the surface of tiny particles of silicon using a technique known as chemical vapor deposition in which a carbon-containing vapor decomposes and then condenses on the surface of the silicon particles forming the nanoscopic tubes. They then coated these particles with carbon released from sugar at a high temperature in a vacuum. A separate batch of silicon particles produced using sugar but without the CNTs was also prepared.

With the new Si-CNT anode material to hand, the team then investigated how well it functioned in a prototype Li-ion battery and compared the results with the material formed from sugar-coated silicon particles.

They found that after twenty cycles of the semi-cell experiments, the sugar-coated Si-CNT composite material achieved a discharge capacity of 727 milliamp hours per gram. In contrast the charge capacity of the simple sugar-coated particles had dropped to just 363 mAh per gram.

Adapted from materials provided by Inderscience Publishers, via EurekAlert!, a service of AAAS.

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2008-04-11T11:44:00.000-07:00

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Atom 'Noise' May Help Design Quantum Computers

2008-03-25T12:08:00.000-07:00

ScienceDaily (Mar. 3, 2007) — As if building a computer out of rubidium atoms and laser beams weren't difficult enough, scientists sometimes have to work as if blindfolded: The quirks of quantum physics can cause correlations between the atoms to fade from view at crucial times.
What to do? Focus on the noise patterns. Building on earlier work by other groups, physicists at the National Institute of Standards and Technology (NIST) have found that images of "noise" in clouds of ultracold atoms trapped by lasers reveal hidden structural patterns, including spacing between atoms and cloud size.

The technique, described in the Feb. 23 issue of Physical Review Letters,* was demonstrated in an experiment to partition about 170,000 atoms in an "optical lattice," produced by intersecting laser beams that are seen by the atoms as an array of energy wells arranged like an egg carton. By loading just one atom into each well, for example, scientists can create the initial state of a hypothetical quantum computer using neutral atoms to store and process information.

The atoms first are cooled to form a Bose-Einstein condensate (BEC), a unique form of matter in which all the atoms are in the same quantum state and completely indistinguishable. The optical lattice lasers then are slowly turned on and the BEC undergoes a transformation in which the atoms space out evenly in the lattice. More intense light creates deeper wells until each atom settles into its own lattice well. But during this transition, scientists lose their capability to see and measure key quantum correlations among the atoms.

Key structures are visible, however, in composite images of the noise patterns, which reveal not only atom spacing but also cloud size and how much of the BEC has undergone the transition.

In the NIST experiments, the BEC was placed in an optical lattice at various laser intensities. The lattice was turned off, and scientists took pictures of the expanding cloud of atoms after 20 to 30 milliseconds. To identify and enhance the noise signal, scientists looked for identical bumps and wiggles in the images and made composites of about 60 images by identifying and overlaying matching patterns. Lead author Ian Spielman likens the technique to listening to a noisy ballroom: While it may be impossible to hear specific conversations, correlations in noise can show where people (or atoms) are located in relation to each other, and the volume of noise can indicate the size of the ballroom (or atomic cloud), Spielman says.

The authors are affiliated with the Joint Quantum Institute, a new collaborative venture of NIST and the University of Maryland. The work was partially supported by the Disruptive Technology Office, an agency of the U.S. intelligence community that funds unclassified research on information systems, and by the Office of Naval Research.

* I.B. Spielman, W.D. Phillips and J.V. Porto. 2007. The Mott insulator transition in a two dimensional atomic Bose gas. Physical Review Letters. Feb. 23.

Adapted from materials provided by National Institute of Standards and Technology.

Stunt Doubles: Ultracold Atoms Could Replicate The Electron 'Jitterbug'

2008-03-25T12:04:00.000-07:00

ScienceDaily (Mar. 13, 2008) — Ultracold atoms moving through a carefully designed arrangement of laser beams will jiggle slightly as they go, two NIST scientists have predicted.* If observed, this never-before-seen "jitterbug" motion would shed light on a little-known oddity of quantum mechanics arising from Paul Dirac's 80-year-old theory of the electron.
Dirac's theory, which successfully married the principles of Einstein's relativity to the quantum property of electrons known as spin, famously predicted that the electron must have an antiparticle, subsequently discovered and named the positron. More enigmatically, the Dirac theory indicates that an isolated electron moving through empty space will vibrate back and forth. But this shaking--named Zitterbewegung from the German for 'trembling motion'--is so rapid and so tiny in amplitude that it has never been directly observed.

Jay Vaishnav and Charles Clark of the Joint Quantum Institute, a partnership of NIST and the University of Maryland, have devised an experimental arrangement in which atoms are made to precisely mimic the behavior of electrons in Dirac's theory. The atoms will show Zitterbewegung--but with vibrations that are slow enough and large enough to be detected.

Vaishnav and Clark's proposal begins with an atom--rubidium-87 is an example--that has a 'tripod' arrangement of electron energy levels, consisting of one higher energy level above three equal-energy lower levels. Suppose, say the researchers, that such atoms are placed in a region crisscrossed by lasers at specific frequencies. Two pairs of laser beams face each other, creating a pattern of standing waves, while a third laser beam is set perpendicular to the other two.

Given the proper frequencies of light, a perfectly stationary "tripod" atom at the intersection will have the energy of its upper state and one of the three lower states slightly changed. To a moving atom, however, the electromagnetic field will look a little different, and in that case the energies of the other two lower states also change slightly.

Remarkably, those two states, moving in this particular arrangement of laser light, are governed by an equation that's exactly analogous to the Dirac equation for the two spin states of an electron moving in empty space. In particular, as the atom moves, it flips back and forth between the two states, and that flipping is accompanied by a jiggling back and forth of the atom's position--a version of Zitterbewegung with a frequency measured in megahertz, a hundred trillion times slower than the vibration of a free electron.

Other arrangements of lasers and atoms have been used to cleanly simulate a variety of quantum systems, says Vaishnav. Examples includes recent studies of the mechanisms of quantum magnetism and high-temperature superconductivity.** What's unusual about this new proposal, she adds, is that it offers a simulation of a fundamental elementary particle in free space and may offer access to an aspect of electron behavior that would otherwise remain beyond observational scrutiny.

* J.Y. Vaishnav and C.W. Clark. Observation of zitterbewegung in ultracold atoms. Presented at the March Meeting of the American Physical Society, March 10, 2008, New Orleans, La., Session A14.00003.

** I. Bloch. Towards quantum magnetism with ultracold quantum gases in optical lattices. Presented at the March Meeting of the American Physical Society, March 12, 2008, New Orleans, La., Session P7.00003. and A.M. Rey. Probing and controlling quantum magnetism with ultra-cold atoms. Presented at the March Meeting of the American Physical Society, March 12, 2008, New Orleans, La., Session P7.00004.

Adapted from materials provided by National Institute of Standards and Technology.

Hyper-entangled Photons: 'Superdense' Coding Gets Denser

2008-03-25T11:59:00.000-07:00

ScienceDaily (Mar. 25, 2008) — The record for the most amount of information sent by a single photon has been broken by researchers at the University of Illinois. Using the direction of "wiggling" and "twisting" of a pair of hyper-entangled photons, they have beaten a fundamental limit on the channel capacity for dense coding with linear optics.
"Dense coding is arguably the protocol that launched the field of quantum communication," said Paul Kwiat, a John Bardeen Professor of Physics and Electrical and Computer Engineering. "Today, however, more than a decade after its initial experimental realization, channel capacity has remained fundamentally limited as conceived for photons using conventional linear elements."

In classical coding, a single photon will convey only one of two messages, or one bit of information. In dense coding, a single photon can convey one of four messages, or two bits of information.

"Dense coding is possible because the properties of photons can be linked to one another through a peculiar process called quantum entanglement," Kwiat said. "This bizarre coupling can link two photons, even if they are located on opposite sides of the galaxy."

Using linear elements, however, the standard protocol is fundamentally limited to convey only one of three messages, or 1.58 bits. The new experiment surpasses that threshold by employing pairs of photons entangled in more ways than one (hyper-entangled). As a result, additional information can be sent and correctly decoded to achieve the full power of dense coding.

Kwiat, graduate student Julio Barreiro and postdoctoral researcher Tzu-Chieh Wei (now at the University of Waterloo) describe their recent experiment in a paper accepted for publication in the journal Nature Physics, and posted on its Web site.

Through the process of spontaneous parametric down conversion in a pair of nonlinear crystals, the researchers first produce pairs of photons simultaneously entangled in polarization, or "wiggling" direction, and in orbital angular momentum, or "twisting" direction. They then encode a message in the polarization state by applying birefringent phase shifts with a pair of liquid crystals.

"While hyper-entanglement in spin and orbital angular momentum enables the transmission of two bits with a single photon," Barreiro said, "atmospheric turbulence can cause some of the quantum states to easily decohere, thus limiting their likely communication application to satellite-to-satellite transmissions."

Adapted from materials provided by University of Illinois at Urbana-Champaign.

Loopy Photons Clarify 'Spookiness' Of Quantum Physics

2008-03-25T11:41:00.000-07:00

ScienceDaily (Mar. 19, 2008) — Researchers at the National Institute of Standards and Technology (NIST) and the Joint Quantum Institute (NIST/University of Maryland) have developed a new method for creating pairs of entangled photons, particles of light whose properties are interlinked in a very unusual way dictated by the rules of quantum physics. The researchers used the photons to test fundamental concepts in quantum theory.
In the experiment, the researchers send a pulse of light into both ends of a twisted loop of optical fiber. Pairs of photons of the same color traveling in either direction will, every so often, interact in a process known as "four-wave mixing," converting into two new, entangled photons, one that is redder and the other that is bluer than the originals.

Although the fiber's twist means that pairs emerging from one end are vertically polarized (having electric fields that vibrate up and down) while pairs from the other end are horizontally polarized (vibrating side to side), the setup makes it impossible to determine which path the newly created photon pairs took. Since the paths are indistinguishable, the weird rules of quantum physics say that the photon pairs actually will be in both states--horizontal and vertical polarization--at the same time. Until someone measures one, at which time both photons must chose one specific, and identical, state.

This "spooky action at a distance" is what caused Einstein to consider quantum mechanics to be incomplete, prompting debate for the past 73 years over the concepts of "locality" and "realism." Decades of experiments have demonstrated that measurements on pairs of entangled particles don't agree with the predictions made by "local realism," the concept that processes occurring at one place have no immediate effect on processes at another place (locality) and that the particles have definite, preexisting properties (called "hidden variables") even without being measured (realism).

Experiments so far have ruled out locality and realism as a combination. But could a theory assuming only one of them be correct" Nonlocal hidden variables (NLHV) theories would allow for the possibility of hidden variables but would concede nonlocality, the idea that a measurement on a particle at one location may have an immediate effect on a particle at a separate location.

Measuring the polarizations of the pairs of entangled particles in their setup, the researchers showed that the results did not agree with the predictions of certain NLHV theories but did agree with the predictions of quantum mechanics. In this way, they were able to rule out certain NLHV theories. Their results agree with other groups that have performed similar experiments.

* J. Fan, M.D. Eisaman and A. Migdall, Bright phase-stable broadband fiber-based source of polarization-entangled photon pairs. Physical Review A 76, 043836 (2007).

** M.D. Eisaman, E.A. Goldschmidt, J. Chen, J. Fan and A. Migdall. Experimental test of non-local realism using a fiber-based source of polarization-entangled photon pairs. Physical Review A., upcoming.

Adapted from materials provided by National Institute of Standards and Technology.

Mass Measurement Technique Uncovers New Iron Isomer

2008-03-25T11:26:00.000-07:00

ScienceDaily (Mar. 24, 2008) — A ground state atomic nucleus can be something of a black box, masking subtle details about its structure behind the aggregate interplay of its protons and neutrons. This is one reason nuclear scientists are so keenly interested in isomers -- relatively long-lived excited-state nuclei that more easily give up their structural secrets to experimentalists.
For years, gamma ray spectroscopy has been one of the only reliable means of studying isomers. But now scientists have a new tool at their disposal. In a paper that will be published in Physical Review Letters, researchers at Michigan State University's National Superconducting Laboratory (NSCL) report the first ever discovery of a nuclear isomer by Penning trap mass spectrometry.

The concept of excitation applies across physics and chemistry to everything from molecules to atoms to nuclei. Consider the basic physics behind a neon light. When voltage is applied across a tube filled with neon gas, the electrons orbiting the neon nuclei briefly are excited to higher energy levels before they come crashing back down to their ground states, releasing visible light.

Nucleons, the protons and neutrons that comprise atomic nuclei, can similarly be raised to higher energy levels. Most resulting excited-state nuclei exist on the briefest of timescales, with lifetimes often measured in trillionths of a second, before the nucleons decay to lower energy states, releasing various forms of radiation. However, some of these excited-state nuclei are quite stable and can exist for much longer periods of time, from fractions of seconds to millions of years.

These relatively long-lived nuclei are called isomers, which are the focus of intense scrutiny by nuclear scientists. Among the open questions about isomers: For which combinations of protons and neutrons can they exist? What are their properties? How long do they live? And what is their excitation energy (the energy required to raise their nucleons to higher energy levels)?

The discovery of the new iron isomer came while using NSCL's Low-Energy Beam and Ion Trap (LEBIT) device to make precision measurements of rare isotopes that are close, in terms of numbers of protons and neutrons, to nickel-68, a particularly enigmatic isotope.

With 28 protons and 40 neutrons, nickel-68 displays some of the characteristics of doubly magic nuclei, so named because they have just the right number of protons and neutrons to completely fill all the energy states, or shells, they occupy. (According to the nuclear shell model, protons and neutrons in most nuclei occupy different energetic shells, completely filling the low-lying states and only partially filling higher states; in doubly magic nuclei, all occupied shells are filled.) However, nuclei with slightly fewer protons and neutrons than nickel-68 reveal pronounced changes in structure, which generally is not the case for isotopes nearby other doubly magic nuclei.

"We have no good idea what is happening in this nuclear region, so more measurements are needed," said Georg Bollen, NSCL professor and co-author of the paper.

The experiment was conducted at NSCL's Coupled Cyclotron Facility, which produced various neutron-rich isotopes of iron and cobalt, including iron-65, with 26 protons and 39 neutrons. (The most abundant stable iron isotope on Earth has 26 protons and 30 neutrons.) These isotopes, produced by smashing beams of germanium nuclei traveling at half the speed of light into thin target material, were brought nearly to rest in a helium gas cell.

Next, the isotopes were guided by a series of electric fields into two ion traps. One was a Penning trap, a device commonly used in atomic and nuclear physics to precisely measure mass. A Penning trap catches and retains charged particles in a strong magnetic field. Responding to this field, captured particles move in what's known as a cyclotron motion, the frequency of which is directly related to the mass of the particle.

During the experiment, Bollen and his collaborators observed two distinct frequencies associated with the trapped iron-65 particles. They concluded that the heavier of the two was a previously unknown isomer of iron-65.

NSCL is the first laboratory in the world to stop fast beams of nuclei such that they can be trapped in space and studied with high precision. Bollen, one of the experts in this discipline at the interface between atomic and nuclear physics, helped to design and build ISOLTRAP, the first Penning trap spectrometer for the study of the mass of short-lived nuclei at the European Organization for Nuclear Research (CERN) in Geneva, Switzerland.

"The nuclear region we looked at still has lots of uncertainty, but we were successful in adding an intriguing new piece of information," said Bollen. "And we did so by going beyond gamma ray spectroscopy, the classical means of studying isomers; finding isomers by weighing nuclei with very high precision bears interesting prospects for future studies."

The research was supported by the National Science Foundation and Michigan State University.

Adapted from materials provided by National Superconducting Cyclotron Laboratory at Michigan State University.

Ultrahigh-energy Cosmic Rays Are From Extremely Far Away

2008-03-25T11:13:00.000-07:00

ScienceDaily (Mar. 25, 2008) — Final results from the University of Utah's High-Resolution Fly's Eye cosmic ray observatory show that the most energetic particles in the universe rarely reach Earth at full strength because they come from great distances, so most of them collide with radiation left over from the birth of the universe.
The findings are based on nine years of observations at the now-shuttered observatory on the U.S. Army's Dugway Proving Ground. They confirm a 42-year-old prediction -- known as the Greisen-Zatsepin-Kuzmin (GZK) "cutoff," "limit" or "suppression" -- about the behavior of ultrahigh-energy cosmic rays, which carry more energy than any other known particle.

The idea is that most -- but not all -- cosmic ray particles with energies above the GZK cutoff cannot reach Earth because they lose energy when they collide with "cosmic microwave background radiation," which was discovered in 1965 and is the "afterglow" of the "big bang" physicists believe formed the universe 13 billion years ago.

The GZK limit's existence was first predicted by Kenneth Greisen of Cornell University while visiting the University of Utah in 1966, and independently by Georgiy Zatsepin and Vadim Kuzmin of Moscow's Lebedev Institute of Physics.

"It has been the goal of much of ultrahigh-energy cosmic ray physics for the past 40 years to find this cutoff or disprove it," says physics Professor Pierre Sokolsky, dean of the University of Utah College of Science and leader of the study by a collaboration of 60 scientists from seven research institutions. "For the first time in 40 years, that question is answered: there is a cutoff."

That conclusion, based on 1997-early 2006 observations at the High Resolution Fly's Eye cosmic ray observatory (nicknamed HiRes) in Utah's western desert, has been bolstered by the new Auger cosmic ray observatory in Argentina. During a cosmic ray conference in Merida, Mexico, last summer, Auger physicists outlined preliminary, unpublished results showing that the number of ultrahigh-energy cosmic rays reaching Earth drops sharply above the cutoff.

So both the HiRes and Auger findings contradict Japan's now-defunct Akeno Giant Air Shower Array (AGASA), which observed roughly 10 times more of the highest-energy cosmic rays -- and thus suggested there was no GZK cutoff.

Cosmic Rays: Far Out

Last November, the Auger observatory collaboration -- to which Sokolsky also belongs -- published a study suggesting that the highest-energy cosmic rays come from active galactic nuclei or AGNs, or the hearts of extremely active galaxies believed to harbor supermassive black holes.

AGNs are distributed throughout the universe, so confirmation that the GZK cutoff is real suggests that if ultrahigh-energy cosmic rays are spewed out by AGNs, they primarily are very distant from the Earth -- at least in Northern Hemisphere skies viewed by the HiRes observatory. University of Utah physics Professor Charlie Jui, a co-author of the new study, says that means galaxies beyond our "local" supercluster of galaxies at distances of at least 150 million light years from Earth, or roughly 870 billion billion miles. [In U.S. usage, billion billion is correct here and in subsequent references for 10 to the 18th power. In British usage, 10 to the 18th power should be million billion.]

However, unpublished results from HiRes do not find the same correlation that Auger did between ultrahigh-energy cosmic rays and active galactic nuclei. So there still is uncertainty about the true source of extremely energetic cosmic rays.

"We still don't know where they're coming from, but they're coming from far away," Sokolsky says. "Now that we know the GZK cutoff is there, we have to look at sources much farther out."

In addition to the University of Utah, High Resolution Fly's Eye scientists are from Los Alamos National Laboratory in New Mexico, Columbia University in New York, Rutgers University -- the State University of New Jersey, Montana State University in Bozeman, the University of Tokyo and the University of New Mexico, Albuquerque.

Messengers from the Great Beyond

Cosmic rays, discovered in 1912, are subatomic particles: the nuclei of mostly hydrogen (bare protons) and helium, but also of some heavier elements such as oxygen, carbon, nitrogen or even iron. The sun and other stars emit relatively low-energy cosmic rays, while medium-energy cosmic rays come from exploding stars.

The source of ultrahigh-energy cosmic rays has been a mystery for almost a century. The recent Auger observatory results have given the edge to the popular theory they originate from active galactic nuclei. They are 100 million times more energetic than anything produced by particle smashers on Earth. The energy of one such subatomic particle has been compared with that of a lead brick dropped on a foot or a fast-pitched baseball hitting the head.

"Quite apart from arcane physics, we are talking about understanding the origin of the most energetic particles produced by the most energetic acceleration process in the universe," Sokolsky says. "It's a question of how much energy the universe can pack into these extraordinarily tiny particles known as cosmic rays. ... How high the energy can be in principle is unknown. By the time they get to us, they have lost that energy."

He adds: "Looking at energy processes at the very edge of what's possible in the universe is going to tell us how well we understand nature."

Ultrahigh-energy cosmic rays are considered to be those above about 1 billion billion electron volts (1 times 10 to the 18th power).

The most energetic cosmic ray ever found was detected over Utah in 1991 and carried an energy of 300 billion billion electron volts (3 times 10 to the 20th power). It was detected by the University of Utah's original Fly's Eye observatory, which was built at Dugway during 1980-1981 and improved in 1986. A better observatory was constructed during 1994-1999 and named the High Resolution Fly's Eye.

Jui says that during its years of operation, HiRes detected only four of the highest-energy cosmic rays -- those with energies above 100 billion billion electron volts. AGASA detected 11, even though it was only one-fourth as sensitive as HiRes.

The new study covers HiRes operations during 1997 through 2006, and cosmic rays above the GZK cutoff of 60 billion billion electron volts (6 times 10 to the 19th power). During that period, the observatory detected 13 such cosmic rays, compared with 43 that would be expected without the cutoff. So the detection of only 13 indicates the GZK limit is real, and that most ultrahigh-energy cosmic rays are blocked by cosmic microwave background radiation so that few reach Earth without losing energy.

The discrepancy between HiRes Fly's Eye and AGASA is thought to stem from their different methods for measuring cosmic rays.

HiRes used multifaceted (like a fly's eye) sets of mirrors and photomultiplier tubes to detect faint ultraviolet fluorescent flashes in the sky generated when incoming cosmic ray particles hit Earth's atmosphere. Sokolsky and University of Utah physicist George Cassiday won the prestigious 2008 Panofsky Prize for developing the method.

HiRes measured a cosmic ray's energy and direction more directly and reliably than AGASA, which used a grid-like array of "scintillation counters" on the ground.

The Search Goes On

University of Tokyo, University of Utah and other scientists now are using the new $17 million Telescope Array cosmic ray observatory west of Delta, Utah, which includes three sets of fluorescence detectors and 512 table-like scintillation detectors spread over 400 square miles -- in other words, the two methods that produced conflicting results at HiRes and AGASA. One goal is to figure out why ground detectors gave an inflated count of the number of ultrahigh-energy cosmic rays.

The Telescope Array also will try to explain an apparent shortage in the number of cosmic rays at energies about 10 times lower than the GZK cutoff. This ankle-shaped dip in the cosmic ray spectrum is a deficit of cosmic rays at energies of about 5 billion billion electron volts.

Sokolsky says there is debate over whether the "ankle" represents cosmic rays that run out of "oomph" after being spewed by exploding stars in our galaxy, or the loss of energy predicted to occur when ultrahigh-energy cosmic rays from outside our galaxy collide with the big bang's afterglow, generating electrons and antimatter positrons.

The Telescope Array and Auger observatories will keep looking for the source of rare ultrahigh-energy cosmic rays that evade the big bang afterglow and reach Earth.

"The most reasonable assumption is they are coming from a class of active galactic nuclei called blazars," Sokolsky says.

Such a galaxy center is suspected to harbor a supermassive black hole with the mass of a billion or so suns. As matter is sucked into the black hole, nearby matter is spewed outward in the form of a beam-like jet. When such a jet is pointed at Earth, the galaxy is known as a blazar.

"It's like looking down the barrel of a gun," Sokolsky says. "Those guys are the most likely candidates for the source of ultrahigh-energy cosmic rays."

The journal Physical Review Letters published the results Friday, March 21. The new study's 60 co-authors include Sokolsky, Jui and 31 other University of Utah faculty members, postdoctoral fellows and students: Rasha Abbasi, Tareq Abu-Zayyad, Monica Allen, Greg Archbold, Konstantin Belov, John Belz, S. Adam Blake, Olga Brusova, Gary W. Burt, Chris Cannon, Zhen Cao, Weiran Deng, Yulia Fedorova, Richard C. Gray, William Hanlon, Petra Huntemeyer, Benjamin Jones, Kiyoung Kim, the late Eugene Loh, Melissa Maestas, Kai Martens, John N. Matthews, Steffanie Moore, Kevin Reil, Robertson Riehle, Douglas Rodriguez, Jeremy D. Smith, R. Wayne Springer, Benjamin Stokes, Stanton Thomas, Jason Thomas and Lawrence Wiencke.

Adapted from materials provided by University of Utah.

Evolution Of Aversion: Why Even Children Are Fearful Of Snakes

2008-03-25T11:09:00.000-07:00

ScienceDaily (Feb. 28, 2008) — Some of the oldest tales and wisest mythology allude to the snake as a mischievous seducer, dangerous foe or powerful iconoclast; however, the legend surrounding this proverbial predator may not be based solely on fantasy. As scientists from the University of Virginia recently discovered, the common fear of snakes may well be intrinsic.
Evolutionarily speaking, early humans who were capable of surviving the dangers of an uncivilized society adapted accordingly. And the same can be said of the common fear of certain animals, such as spiders and snakes: The ancestors of modern humans were either abnormally lucky or extraordinarily capable of detecting and deterring the threat of, for example, a poisonous snake.

Psychologists Vanessa LoBue and Judy DeLoache were able to show this phenomenon by examining the ability of adults and children to pinpoint snakes among other nonthreatening objects in pictures.

“We wanted to know whether preschool children, who have much less experience with natural threats than adults, would detect the presence of snakes as quickly as their parents,” LoBue explained. “If there is an evolved tendency in humans for the rapid detection of snakes, it should appear in young children as well as their elders.”

Preschool children and their parents were shown nine color photographs on a computer screen and were asked to find either the single snake among eight flowers, frogs or caterpillars, or the single nonthreatening item among eight snakes. As the study surprisingly shows, parents and their children identified snakes more rapidly than they detected the other stimuli, despite the gap in age and experience.

LoBue and DeLoache also found that both children and adults who don't fear snakes are just as good at quickly identifying them as children and adults who do fear snakes, indicating that there may be a universal human ability to visually detect snakes whether there is or is not a fear factor based on a learned bias or experience.

LoBue and DeLoache explain that their study does not prove an innate fear of snakes, only that humans, including young children, seem to have an innate ability to quickly identify a snake from among other things. One of their previous studies indicated that humans also have a profound ability to identify spiders from among non-threatening flora and fauna. Lobue has also shown that people are very good at quickly detecting threats of many types, including aggressive facial expressions.

The results, which appear in the March 2008 issue of Psychological Science, a journal of the Association for Psychological Science, may provide the first evidence of an adapted, visually-stimulated fear mechanism in humans.

Adapted from materials provided by Association for Psychological Science.

Unlocking The Psychology Of Snake And Spider Phobias

2008-03-25T11:06:00.000-07:00

ScienceDaily (Mar. 24, 2008) — University of Queensland researchers have unlocked new evidence that could help them get to the bottom of our most common phobias and their causes.
Hundreds of thousands of people count snakes and spiders among their fears, and while scientists have previously assumed we possess an evolutionary predisposition to fear the unpopular animals, researchers at UQ's School of Psychology may have proved otherwise.

According to Dr Helena Purkis, the results of the UQ study could provide an unprecedented insight into just why the creepy creatures are so widely feared.

“Previous research shows we react differently to snakes and spiders than to other stimuli, such as flowers or mushrooms, or even other dangerous animals….or cars and guns, which are also much more dangerous,” Dr Purkis said.

“[In the past, this] has been explained by saying that people are predisposed by evolution to fear certain things, such as snakes and spiders, that would have been dangerous to our ancestors.

“[However], people tend to be exposed to a lot of negative information regarding snakes and spiders, and we argue this makes them more likely to be associated with phobia.”

In the study, researchers compared the responses to stimuli of participants with no particular experience with snakes and spiders, to that of snake and spider experts.

“Previous research has argued that snakes and spiders attract preferential attention (they capture attention very quickly) and that during this early processing a negative (fear) response is generated… as an implicit and indexed subconscious [action],” Dr Purkis said.

“We showed that although everyone preferentially attends to snakes or spiders in the environment as they are potentially dangerous, only inexperienced participants display a negative response.”

The study is the first to establish a clear difference between preferential attention and the accompanying emotional response: that is, that you can preferentially attend to something without a negative emotional response being elicited.

Dr Purkis said the findings could significantly increase understanding about the basic cognitive and emotional processes involved in the acquisition and maintenance of fear.

“If we understand the relationship between preferential attention and emotion it will help us understand how a stimulus goes from being perceived as potentially dangerous, to eliciting an emotional response and to being associated with phobia,” she said.

“[This] could give us some information about the way people need to deal with snakes and spiders in order to minimise negative emotional responses.”

Researchers are now planning a follow-up study, which will test their theory that love and fear, or phobia, involve the same basic attention mechanism.

“We are interested in testing animal stimuli for animal lovers to see whether these stimuli, a dog for a breeder for instance, have access to preferential attention [in the same way as snakes and spiders do for those with phobias of them].

“I am also interested in the difference that we saw in our previous work between preferential attention, and the emotional response that is elicited after this initial processing."

The study calls for volunteers who work with or own dogs, cats, horses, cattle, snakes and spiders and also general members of the public who will form a control group.

“I also need people who are allergic to dogs or cats, people who are apprehensive of snakes and spiders, and people who have no fear of snakes and spiders but don't explicitly work with them,” Dr Purkis said.

“[Additionally, we're looking to get in touch with] people who are willing to have their pets (dogs, cats, horses, cattle, snakes, spiders) photographed for use as experimental stimuli.”

Adapted from materials provided by University of Queensland.

Killer Military Robots Pose Latest Threat To Humanity, Robotics Expert Warns

2008-03-25T10:50:00.001-07:00

ScienceDaily (Feb. 28, 2008) — A robotics expert at the University of Sheffield has issued stark warnings over the threat posed to humanity by new robot weapons being developed by powers worldwide.

In a keynote address to the Royal United Services Institute (RUSI), Professor Noel Sharkey, from the University's Department of Computer Science, expressed his concerns that we are beginning to see the first steps towards an international robot arms race. He will warn that it may not be long before robots become a standard terrorist weapon to replace the suicide bomber.

Many nations are now involved in developing the technology for robot weapons, with the US Department of Defence (DoD) being the most significant player. According to the Unmanned Systems Roadmap 2007-2013 (published in December 2007), the US propose to spend an estimated $4 billion by 2010 on unmanned systems technology. The total spending is expected to rise above $24 billion.

Over 4,000 robots are currently deployed on the ground in Iraq and by October 2006 unmanned aircraft had flown 400,000 flight hours. Currently there is always a human in the loop to decide on the use of lethal force. However, this is set to change with the US giving priority to autonomous weapons - robots that will decide on where, when and who to kill.

Others are now embarking on robot weapons programmes in Europe and other allied countries such as Canada, South Korea, South Africa, Singapore and Israel. China, Russia and India are also embarking on the development of unmanned aerial combat vehicle. The US DoD report is unsure about the activity in China but admits that they have strong infrastructure capability for parallel developments in robot weapons.

Professor Sharkey, who is famously known for his roles as chief judge on the TV series Robot Wars and as onscreen expert for the BBC´s TechnoGames, said: "The trouble is that we can't really put the genie back in the bottle. Once the new weapons are out there, they will be fairly easy to copy. How long is it going to be before the terrorists get in on the act?"

"With the current prices of robot construction falling dramatically and the availability of ready-made components for the amateur market, it wouldn't require a lot of skill to make autonomous robot weapons."

Professor Sharkey is reluctant to explain how such robots could be made but he points out that a small GPS guided drone with autopilot could be made for around £250.

The robotics expert is also concerned with a number of ethical issues that arise from the use of autonomous weapons. He added: "Current robots are dumb machines with very limited sensing capability. What this means is that it is not possible to guarantee discrimination between combatants and innocents or a proportional use of force as required by the current Laws of War.

"It seems clear that there is an urgent need for the international community to assess the risks of these new weapons now rather than after they have crept their way into common use."

Professor Sharkey's talk was at a one-day conference at RUSI in Whitehall on 27 February 2008.

Adapted from materials provided by University of Sheffield, via EurekAlert!, a service of AAAS.

Wireless Networks That Build Themselves

2008-03-25T10:38:00.000-07:00

ScienceDaily (Mar. 14, 2008) — From traffic lights to mobile phones, small computers are all around us. Enabling these ‘embedded systems’ to create wireless communications networks automatically will have profound effects in areas from emergency management to healthcare and traffic control.
Networks of mobile sensors and other small electronic devices have huge potential. Applications include emergency management, security, helping vulnerable people to live independently, traffic control, warehouse management, and environmental monitoring.

One scenario investigated by European researchers was a road-tunnel fire. With fixed communications destroyed and the tunnel full of smoke, emergency crews would normally struggle to locate the seat of the blaze and people trapped in the tunnel.

Wireless sensors could cut through the chaos by providing the incident control room with information on visibility, temperatures, and the locations of vehicles and people. Firefighters inside the tunnel could then receive maps and instructions through handheld terminals or helmet-mounted displays.

For this vision to become reality, mobile devices have to be capable of forming self-organising wireless networks spanning a wide variety of communications technologies. Developing software tools to make this possible was the task of the RUNES project.

Intelligent networking

‘Ad-hoc’ mobile networks are very different from the wireless computer networks in homes and offices, explains Dr Lesley Hanna, a consultant and dissemination manager for RUNES. Without a human administrator, an ad-hoc network must assemble itself from any devices that happen to be nearby, and adapt as devices move in and out of wireless range. And where office networks use powerful computers with separate routers, the building blocks of ad-hoc mobile networks are low-power devices that must do their own wireless routing, forwarding signals from other devices that would otherwise be out of radio range.

A typical network could contain tens or even hundreds of these ‘embedded systems’, ranging from handheld computers down to ‘motes’: tiny units each equipped with a sensor, a microcontroller and a radio that can be scattered around an area to be monitored. Other devices could be mounted at fixed points, carried by robots, or worn as ‘smart clothing’ or ‘body area networks’.

Wireless standards are not the issue: most mobile devices use common protocols, such as GSM, Wi-Fi, Bluetooth and ZigBee. The real challenge, suggests Hanna, is to build self-managing networks that work reliably on a large scale, with a variety of operating systems and low-power consumption.

Middleware and more

The EU-funded RUNES (Reconfigurable Ubiquitous Networked Embedded Systems) covered 21 partners in nine countries. Although RUNES was led by Ericsson, it had an academic bias, with twice as many universities as industrial partners, and most of the resulting software is publicly available.

RUNES set out to create middleware: software that bridges the gap between the operating systems used by the mobile sensor nodes, and high-level applications that make use of data from the sensors. RUNES middleware is modular and flexible, allowing programmers to create applications without having to know much about the detailed working of the network devices supplying the data. This also makes it easy to incorporate new kinds of mobile device, and to re-use applications.

Interoperability was a challenge, partly because embedded systems themselves are so varied. At one end of the spectrum are powerful environments, such as Java, while at the other are simple systems designed for wireless sensors. For devices with small memories, RUNES developed middleware modules that can be uploaded, used to carry out specific tasks, and then overwritten.

Project partners also worked on an operating system and a simulator. Contiki is an open-source operating system designed for networked, embedded systems with small amounts of memory. Simics, a simulator allowing large networks to be tested in ways that are impractical with real hardware, is commercially available from project partner Virtutech.

Taking the plunge

The tunnel fire scenario was valuable in demonstrating what networks of this kind can achieve. Using real sensor nodes, routers, gateways and robots developed during the project, a demonstration setup showed how, for instance, a robot router can manoeuvre itself to cover a gap in the network’s wireless coverage.

“A lot of people have been looking at embedded systems networking, but so far there has been a reluctance to take the plunge commercially,” says Hanna. “RUNES’ open-source model is an excellent way to stimulate progress, and it should generate plenty of consultancy work for the academic partners.”

Adapted from materials provided by ICT Results.

Computers Show How Bats Classify Plants According To Their Echoes

2008-03-25T10:32:00.000-07:00

ScienceDaily (Mar. 24, 2008) — Researchers have developed a computer algorithm that can imitate the bat's ability to classify plants using echolocation. The study represents a collaboration between machine learning scientists and biologists studying bat orientation.
To detect plants, bats emit ultrasonic pulses and decipher the various echoes that return. Bats use plants daily as food sources and landmarks for navigation between foraging sites. Plant echoes are highly complex signals due to numerous reflections from leaves and branches. Classifying plants or other intricate objects, therefore, has been considered a troublesome task for bats and the scientific community was far from understanding how they do it.

Now, a research group in Tübingen, Germany, including University of Tübingen researchers Yossi Yovel, Peter Stilz and Hans Ulrich-Schnitzler, and Matthias Franz from the Max Planck Institute of Biological Cybernetics, has demonstrated that this process of plant classification is not as difficult as previously thought.

The group used a sonar system to emit bat-like, frequency-modulated ultrasonic pulses. The researchers recorded thousands of echoes from live plants of five species. An algorithm that uses the time-frequency information of these echoes was able to classify plants with high accuracy. This new algorithm also provides hints toward which echo characteristics might be best understood by the bats.

According to the group, these results enable us to improve our understanding of this fascinating ability of how bats classify plants, but do so without entering the bat's brain.

Journal reference: Yovel Y, Franz MO, Stilz P, Schnitzler H-U (2008). Plant Classification from Bat-Like Echolocation Signals. PLoS Comput Biol 4(3): e1000032. doi:10.1371/journal.pcbi.1000032

Adapted from materials provided by Public Library of Science, via EurekAlert!, a service of AAAS.

First Humanoid Robot That Will Develop Language May Be Coming Soon

2008-03-15T12:20:00.000-07:00

ScienceDaily (Mar. 4, 2008) — iCub, a one metre-high baby robot which will be used to study how a robot could quickly pick up language skills, will be available next year.
Professor Chrystopher Nehaniv and Professor Kerstin Dautenhahn at the University of Hertfordshire’s School of Computer Science are working with an international consortium led by the University of Plymouth on ITALK (Integration and Transfer of Action and Language Knowledge in Robots), which begins on 1 March.

ITALK aims to teach the robot to speak by employing the same methods used by parents to teach their children. Professor Nehaniv and Professor Dautenhahn, who are European leaders in Artificial Intelligence and Human Robot Interaction, will conduct experiments in human and robot language interaction to enable the robot to converse with humans.

Typical experiments with the iCub robot will include activities such as inserting objects of various shapes into the corresponding holes in a box, serialising nested cups and stacking wooden blocks. Next, the iCub will be asked to name objects and actions so that it acquires basic phrases such as "robot puts stick on cube".

Professor Nehaniv said: “Our approach is that robot will use what it learns individually and socially from others to bootstrap the acquisition of language, and will use its language abilities in turn to drive its learning of social and manipulative abilities. This creates a positive feedback cycle between using language and developing other cognitive abilities. Like a child learning by imitation of its parents and interacting with the environment around it, the robot will master basic principles of structured grammar, like negation, by using these abilities in context.”

The scientific and technological research developed during the project will have a significant impact on the future generation of interactive robotic systems within the next ten years and the leadership role of Europe in this area.

Speaking about the research, Professor Dautenhahn said: “iCub will take us a stage forward in developing robots as social companions. We have studied issues such as how robots should look and how close people will want them to approach and now, within a year, we will have the first humanoid robot capable to developing language skills.”

Adapted from materials provided by University of Hertfordshire.

Mind Over Body: New Hope For Quadriplegics

2008-03-15T12:13:00.000-07:00

ScienceDaily (Mar. 12, 2008) — Around 2.5 million people worldwide are wheelchair bound because of spinal injuries. Half of them are quadriplegic, paralysed from the neck down. European researchers are now offering them new hope thanks to groundbreaking technology that uses brain signals alone to control computers, artificial limbs and even wheelchairs.

People left paralysed by spinal injuries or suffering from neurodegenerative diseases could regain a degree of independence thanks to a new type of non-intrusive brain-computer interface, or BCI, developed by the MAIA project.

Using electrical signals emitted by the brain and picked up by electrodes attached to the user’s scalp, the system allows people to operate devices and perform tasks that previously they could only dream of. So far, the team, led by the IDIAP Research Institute in Switzerland, has carried out a series of successful trials in which users have been able to manoeuvre a wheelchair around obstacles and people using brainpower alone.

“We have demonstrated that it is possible for someone to control a complex mechanical device with their minds, and this opens up all sorts of possibilities,” says MAIA coordinator José del R. Millán.

Though BCIs, for people with impaired movement and for other uses, have been under development for many years, they have had varying degrees of success, largely because of the difficulties of turning brain signals into accurate mechanical movement. What sets the EU-funded MAIA system apart is that it does not rely on the human brain alone to do all the work, instead incorporating artificial intelligence into the device being used.

Intelligence meets artificial intelligence

A person using the MAIA BCI to control a wheelchair, for example, only has to think about going straight ahead or turning left and the chair follows their command. However, they do not have to worry about colliding with obstacles – even moving ones such as people – because the wheelchair itself monitors and reacts to its environment.

“A user can tell the chair to go straight ahead, but it will not just randomly roll in that direction if there is a wall or a flight of stairs in the way,” Millán notes. “What we have done is combine the intelligence of the person with the artificial intelligence of the device.”

In a sense, the artificial intelligence embedded in the chair acts much like a human’s subconscious. People, for example, do not consciously send commands to every muscle in each leg in order to walk and do not think where to step to avoid an obstacle – they do it subconsciously. Similarly, a wheelchair-bound user of the MAIA BCI simply has to send the signal to go in a certain direction and the chair figures out how to get there.

But the user always stays in control!

Keeping the user in control

“We wanted to see how much of the movement was down to the user’s brain signals and how much was due to the intelligence of the chair. It turned out that the wheelchair intervened between 10 and 40 percent of the time depending on the user and the environment.

“In one demonstration in which someone was manoeuvring the chair for six hours, the computer intelligence kicked in more frequently later on as the person became increasingly tired and made more mistakes,” Millán says.

Importantly, the chair can recognise from the user’s brain signals if it has made a mistake, and, through tactile devices similar to the vibrators used in mobile phones, it can send feedback to users about the direction they are going that enhances their sense of awareness beyond the visual.

Millán notes that the same technology could be applied to artificial limbs to allow quadriplegics to pick up objects or unlock a door. By using the BCI to interact with computer systems, meanwhile, they could control the lighting in their homes, surf the internet, or change the channels on the TV. Those simpler brain-computer interactions, which have the potential to become the basis for commercial systems sooner, will be the focus of a follow-up EU project called TOBI that is due to begin in September and which will also be led by Millán.

“For a wheelchair, such as the one developed in MAIA, to reach the market would take extensive trials to prove that the technology is robust enough. We can’t have it breaking down when someone is in the middle of the street,” Millán notes.

Carrying out such validation trials remains a goal of the project partners who are actively seeking further funding and investment to continue their work.

Adapted from materials provided by ICT Results.

Ethanol Imports From Latin America May Help US Meet Energy Goals

2008-03-15T12:03:00.000-07:00

ScienceDaily (Mar. 5, 2008) — Latin American nations could become important suppliers of ethanol for world markets in coming decades, according to an Oak Ridge National Laboratory study released recently.
The ORNL study* highlights the importance of Brazil's dynamic sugarcane industry in future world trade in fuel ethanol.

A team of ORNL researchers led by Keith Kline and Gbadebo Oladosu projected that Brazil, Argentina, Colombia and members of the Caribbean Basin Initiative could produce sufficient feedstock for more than 30 billion gallons of ethanol per year by 2017, which would represent a six-fold increase over current production. Nearly 40 percent of the projected supply in 2017 is based on the potential to use new technology to produce advanced biofuels from cellulosic feedstock using crop residues and forestry byproducts.

"Current feedstock production, based on traditional crops such as sugarcane, soybeans and palm oil, has the potential to double or triple by 2017 in some cases," said Oladosu, the lead economist for the study. "Supply growth is derived from increasing the area cultivated, supplemented by improving yields and farming practices."

Although it was not a focus for this research, the researchers highlighted implications for potential land use change.

The ORNL report assembles historic data on feedstock production for multiple countries and crops and calculates future production and the potential supplies available for export. Included in the report are detailed graphs, tables and disaggregated data for feedstock supplies under a range of future growth possibilities.

"The supply projections provide analysts and policymakers with better data on which to base decisions," Kline said. "The potential for future biofuel feedstock production in Latin America offers interesting opportunities for the U.S. and developing nations."

Results suggest that an increasing portion of U.S. fossil fuel imports that now arrive from distant nations in Africa and the Middle East Asia could be replaced by renewable biofuels from neighbors in the Americas.

Paul Leiby, an ORNL expert on energy security, notes that ethanol from trading partners in this hemisphere could offer many mutual benefits: more reliable and diversified U.S. fuel supply, improved rural livelihoods in Latin America, reductions in greenhouse gas emissions and the expanded availability of biofuel in many urban markets via delivery at coastal ports.

"Biofuel imports complement domestic biofuel production and diminish reliance on oil, the price of which is unstable and strongly influenced by the OPEC cartel," Leiby said. "Even if imported, biofuels can improve our energy security by reducing oil imports and expanding our base of independent fuel sources. Best of all, American consumers could pay less at the pump during energy emergencies."

ORNL's study focuses on assessing future potential for feedstock production in Argentina, Brazil, Canada, China, Colombia, India, Mexico and the Caribbean Basin region. Countries were selected based on their potential to impact world biofuel markets, proximity to the U.S. and other criteria. The research team hopes to expand the analysis to include additional nations in Asia and Africa over the coming year.

The report, available at the website noted below, provides supply curves for selected countries and feedstocks projected to 2012, 2017 and 2027. Highlights include:

* If the total projected feedstock supply calculated as "available" for export or biofuel in 2017 from these countries were converted to biofuel, it would represent the equivalent of about 38 billion gallons of gasoline.
* Sugarcane and bagasse, the solid residue after juices are pressed from the sugarcane stalk, form the bulk of potential future feedstock supplies, representing about two-thirds of the total available for export or biofuel in 2017.
* Soybeans are next in importance in terms of available supply potential in 2017, representing about 18 percent of the total.
* Most future supplies of corn and wheat are projected to be allocated to food and feed and would not be available for biofuels. Canada may be an exception because government programs will likely cause these crops to be used as feedstock to meet their domestic biofuel targets over the coming decade.
* In the various countries assessed, recent changes in national policies and laws are catalyzing investments in biofuel industries to meet targets for fuel blending that generally fall in the 5 percent to 10 percent range.
* Social and environmental concerns associated with the expansion of feedstock production are considered in the report, including land availability and efforts to establish systems for certification of sustainable production.
* Sugarcane dominates potential supply among the crops studied while bagasse -- the crushed stalk residue from sugarcane processing -- and forest industry residues are the principle sources among potential cellulosic supplies.

*The report, "Biofuel Feedstock Assessment for Selected Countries," presents findings from research conducted in support of a larger study of "Worldwide Potential to Produce Biofuels with a focus on U.S. Imports" by the Department of Energy.

Also contributing to the ORNL report were Bob Perlack, Amy Wolfe and Virginia Dale of ORNL's Environmental Sciences Division and Matt McMahon, a summer intern from Appalachian State University.

This research was jointly funded by DOE's Office of Policy and International Affairs and the Office of Energy Efficiency and Renewable Energy, Biomass Programs. UT-Battelle manages Oak Ridge National Laboratory for the Department of Energy.

Adapted from materials provided by DOE/Oak Ridge National Laboratory.

Nuclear Fuel Performance Milestone Achieved

2008-03-15T11:53:00.000-07:00

ScienceDaily (Mar. 13, 2008) — Researchers at the U.S. Department of Energy's Idaho National Laboratory, in partnership with three other science and engineering powerhouses, reached a major domestic milestone relating to nuclear fuel performance on March 8.
David Petti, Sc.D., and technical director for the INL research, says the team used reverse engineering methods to help turn the fuel test failures from the early 1990s into successes in 2008. "We wanted to close this loop for the high-temperature gas reactor fuels community," he said. "We wanted to put more science into the tests and take the process and demonstrate its success."

The research is key in supporting reactor licensing and operation for high-temperature reactors such as the Next Generation Nuclear Plant and similar reactors envisioned for subsequent commercial energy production.

"Hats off to the R&D fuels team on this major milestone," said Greg Gibbs, Next Generation Nuclear Plant Project director. "This is a major accomplishment in demonstrating TRISO fuel safety. This brings us one step closer to licensing a commercially-capable, high-temperature gas reactor that will be essentially emission free, help curb the rising cost of energy and help to achieve energy security for our country."

The work is a team effort of more than 40 people from INL, The Babcock & Wilcox Company, General Atomics and Oak Ridge National Laboratory.

"I salute the team effort that made the research the success it is today," said David Hill, INL deputy laboratory director for Science and Technology. "I saw the research start while I was part of the ORNL team, and to see it succeed today is hugely satisfying and a tribute to everyone involved."

The team has now set its sights on reaching its next major milestone -- achievement of a 12-14 percent burnup* expected later this calendar year.

Research details

The research to improve the performance of coated-particle nuclear fuel met an important milestone by reaching a burnup of 9 percent without any fuel failure. Raising the burnup level of fuel in a nuclear reactor reduces the amount of fuel required to produce a given amount of energy while reducing the volume of the used fuel generated, and improves the overall economics of the reactor system.

After U.S. coated-particle fuel performance difficulties in the 1990s and a shift in national priorities, research on this type of fuel was curtailed for a time. Funding for the research resumed in 2003 as part of the DOE Advanced Gas Reactor fuel development and qualification program.

The team studied the very successful technology developed by the Germans for this fuel in the 1980s and decided to make the carbon and silicon carbide layers of the U.S. particle coatings more closely resemble the German model. The changes resulted in success that has matched the historical German level.

INL's Advanced Test Reactor was a key enabler of the successful research. The ATR was used to provide the heating of the fuel to watch the fuel's response. The fuel kernel is coated with layers of carbon and silicon compounds. These microspheres are then placed in compacts one-half-inch wide by two inches long and then placed in graphite inside the reactor for testing. The fuel element is closely monitored while inside the test reactor to track its behavior.

*A burnup is a measure of the neutron irradiation of the fuel. Higher burnup allows more of the fissile 235U and of the plutonium bred from the 238U to be utilised, reducing the uranium requirements of the fuel cycle.

Adapted from materials provided by DOE/Idaho National Laboratory, via EurekAlert!, a service of AAAS.

Toward A Healthier Food For Fido: Corn Provides Promising Fiber Alternative

2008-03-15T11:50:00.001-07:00

ScienceDaily (Feb. 27, 2008) — In addition to helping fill gasoline tanks with alcohol-based fuel, corn may have a new role in filling Fido's bowl with more healthful food, nutritional biochemists in Illinois are reporting. They found that corn fiber shows promise as a more economical and healthier ingredient in dog food than some of the fibers now in use.
George Fahey and colleagues point out that the fiber content of dog food varies widely and is often of inferior quality. Many dog foods use fiber from sugar beet pulp. Corn fiber -- available in large amounts as a byproduct of ethanol production -- is an attractive alternative. However, researchers have little information on corn fiber's effects in dogs.

In the new study, researchers studied digestion, food intake, and fecal characteristics in dogs fed either a special food containing corn fiber or a standard food containing beet fiber. Substituting corn fiber for beet fiber "does not dramatically impact nutrient digestibility, food intake, or fecal production and characteristics," the researchers say. Corn fiber should therefore be considered a promising fiber alternative for use in dog food, they note. Previous studies suggest that corn fiber in animal food could have beneficial effects in reducing risks of obesity and diabetes.

The study "Chemical Composition, in Vitro Fermentation Characteristics, and in Vivo Digestibility Responses by Dogs to Select Corn Fibers" is scheduled for the March 26 issue of ACS' Journal of Agricultural and Food Chemistry. doi: 10.1021/jf073073b

Adapted from materials provided by American Chemical Society, via EurekAlert!, a service of AAAS.

Fight Against Obesity: Increase Cells' Energy Consumption With Mitochondrial Uncoupling?

2008-03-15T11:37:00.000-07:00

ScienceDaily (Mar. 15, 2008) — With obesity still on the increase, it appears that the main weapon in the fight against it - reducing energy consumption by eating less - is ineffective. There is evident need to search for new treatment strategies dealing with the opposite aspect of the energy balance: increasing energy consumption. Researchers at Maastricht University have now found a way to increase cells' energy consumption: mitochondrial uncoupling.

PhD candidate Sander Wijers and his colleagues Patrick Schrauwen, Prof. Wim Saris and Wouter van Marken Lichtenbelt have shown that this process occurs naturally in human skeletal muscle cells when exposed to mild cold. They carried out muscle biopsies on 11 lean, healthy male subjects both under normal and mild cold conditions. Their results could lead to the development of drugs that stimulate mitochondrial uncoupling, and thus contribute to obesity treatment.

Fats and sugars are broken down in the mitochondria, or energy factories of the cells. ATP - the energy source used, for example, when muscles contract and for many other cellular processes - is formed using the energy released in this process. In some cases, such as when exposed to cold, not all the energy released from sugars and fats is used to produce ATP; stored energy is used for heat, reducing the availability of ATP for cellular processes. This phenomenon is called mitochondrial uncoupling. Fats and sugars are still broken down in the uncoupled mitochondria, but the energy released is not entirely used for cellular processes. More energy is therefore required to carry out the same physical functions.

Further genomic and proteomic research is required to identify the proteins responsible for uncoupling in skeletal muscle mitochondria. The animal proteins UCP1, UCP2, UCP4 and UCP5 detected in tests appear not to exist in human muscle tissue. And although UCP3 is found in human muscles, it seems to be involved primarily in fatty acid metabolism, not in mitochondrial uncoupling.

Citation: Wijers SLJ, Schrauwen P, Saris WHM, van Marken Lichtenbelt WD (2008) Human Skeletal Muscle Mitochondrial Uncoupling Is Associated with Cold Induced Adaptive Thermogenesis. PLoS One 3(3): e1777. doi:10.1371/journal.pone.0001777 http://www.plosone.org/doi/pone.0001777

Adapted from materials provided by Public Library of Science, via EurekAlert!, a service of AAAS.

Coolest Winter Since 2001 For U.S., Globe, According To NOAA Data

2008-03-15T11:22:00.000-07:00

ScienceDaily (Mar. 15, 2008) — The average temperature across both the contiguous U.S. and the globe during climatological winter (December 2007-February 2008) was the coolest since 2001, according to scientists at NOAA’s National Climatic Data Center in Asheville, N.C. In terms of winter precipitation, Pacific storms, bringing heavy precipitation to large parts of the West, produced high snowpack that will provide welcome runoff this spring.
U.S. Winter Temperature Highlights

In the contiguous United States, the average winter temperature was 33.2°F (0.6°C), which was 0.2°F (0.1°C) above the 20th century average – yet still ranks as the coolest since 2001. It was the 54th coolest winter since national records began in 1895.

Winter temperatures were warmer than average from Texas to the Southeast and along the Eastern Seaboard, while cooler-than-average temperatures stretched from much of the upper Midwest to the West Coast.

With higher-than-average temperatures in the Northeast and South, the contiguous U.S. winter temperature-related energy demand was approximately 1.7 percent lower than average, based on NOAA’s Residential Energy Demand Temperature Index.

U.S. Winter Precipitation Highlights

Winter precipitation was much above average from the Midwest to parts of the West, notably Kansas, Colorado and Utah. Although moderate-to-strong La Niña conditions were present in the equatorial Pacific the winter was unique for the above average rain and snowfall in the Southwest, where La Niña typically brings drier-than-average conditions.

During January alone, 170 inches of snow fell at the Alta ski area near Salt Lake City, Utah, more than twice the normal amount for the month, eclipsing the previous record of 168 inches that fell in 1967. At the end of February, seasonal precipitation for the 2008 Water Year, which began on October 1, 2007, was well above average over much of the West.

Mountain snowpack exceeded 150 percent of average in large parts of Colorado, New Mexico, Arizona, and Oregon at the end of February. Spring run-off from the above average snowpack in the West is expected to be beneficial in drought plagued areas.

Record February precipitation in the Northeast helped make the winter the fifth wettest on record for the region. New York had its wettest winter, while Pennsylvania, Connecticut, Vermont, and Colorado to the West, had their second wettest.

Snowfall was above normal in northern New England, where some locations posted all-time record winter snow totals. Concord, N.H., received 100.1 inches, which was 22.1 inches above the previous record set during the winter of 1886-87. Burlington, Vt., received 103.2 inches, which was 6.3 inches above the previous record set during the winter of 1970-71.

While some areas of the Southeast were wetter than average during the winter, overall precipitation for the region was near average. At the end of February, two-thirds of the Southeast remained in some stage of drought, with more than 25 percent in extreme-to- exceptional drought.

Drought conditions intensified in Texas with areas experiencing drought almost doubling from 25 percent at the end of January to 45 percent at the end of February.

Global Highlights

The combined global land and ocean surface temperature was the 16th warmest on record for the December 2007-February 2008 period (0.58°F/0.32°C above the 20th century mean of 53.8°F/12.1°C). The presence of a moderate-to-strong La Niña contributed to an average temperature that was the coolest since the La Niña episode of 2000-2001.

While analyses of the causes of the severe winter storms in southern China continues, NOAA Earth System Research Laboratory scientists are focusing on the presence of unusually strong, persistent high pressure over Eastern Europe, combined with low pressure over Southwest Asia. This pattern directed a series of storms across the region, while northerly low level flow introduced cold air from Mongolia. Unusually high water temperatures in the China Sea may have triggered available moisture that enhanced the severity of these storms.

Record Northern Hemisphere snow cover extent in January was followed by above average snow cover for the month of February. Unusually high temperatures across much of the mid- and high-latitude areas of the Northern Hemisphere in February began reducing the snow cover, and by the end of February, snow cover extent was below average in many parts of the hemisphere.

While there has been little trend in snow cover extent during the winter season since records began in the late 1960s, spring snow cover extent has been sharply lower in the past two decades as global temperatures have increased.

February Temperature Highlights

February was 61st warmest in the contiguous U.S. and 15th warmest globally on record. For the U.S., the temperature was near average, 0.2°F (0.1°C) above the 20th century average of 34.7°F (1.5°C), which was 2.0°F (1.1°C) warmer than February 2007.

Globally, the February average temperature was 0.68°F/0.38°C above the 20th century mean of 53.8°F/12.1°C.

Adapted from materials provided by National Oceanic And Atmospheric Administration.

Two-Dimensional High-Temperature Superconductor Discovered

2008-03-15T11:18:00.000-07:00

ScienceDaily (Mar. 14, 2008) — Scientists at Brookhaven Lab have discovered a state of two-dimensional (2D) fluctuating superconductivity in a high-temperature superconductor with a particular arrangement of electrical charges known as "stripes."
The finding was uncovered during studies of directional dependence in the material's electron-transport and magnetic properties. In the 2D plane, the material acts as a superconductor - conducts electricity with no resistance - at a significantly higher temperature than in the 3D state.

"The results provide many insights into the interplay between the stripe order and superconductivity, which may shed light on the mechanism underlying high-temperature superconductivity," said Brookhaven physicist Qiang Li.

Understanding the mechanism of high-temperature superconductivity is one of the outstanding scientific issues in condensed matter physics, Li said. Understanding this mechanism could lead to new strategies for increasing the superconducting transition temperature of other superconductors to make them more practical for applications such as electrical transmission lines.

"As electricity demand increases, the challenge to the national electricity grid to provide reliable power will soon grow to crisis levels," Li said. "Superconductors offer powerful opportunities for restoring the reliability of the power grid and increasing its capacity and efficiency by providing reactive power reserves against blackouts, and by generating and transmitting electricity."

This research was presented at The March 2008 American Physical Society Meeting in New Orleans, La., March 10 -14.

Adapted from materials provided by DOE/Brookhaven National Laboratory.

Meditation Can Lower Blood Pressure, Study Shows

2008-03-15T11:12:00.000-07:00

ScienceDaily (Mar. 15, 2008) — Transcendental Meditation is an effective treatment for controlling high blood pressure with the added benefit of bypassing possible side effects and hazards of anti-hypertension drugs, according to a new meta-analysis conducted at the University of Kentucky.
The meta-analysis evaluated nine randomized, controlled trials using Transcendental Meditation as a primary intervention for hypertensive patients. The practice of Transcendental Meditation was associated with approximate reductions of 4.7 mm systolic blood pressure and 3.2 mm diastolic blood pressure.

The study's lead author, Dr. James W. Anderson, professor of medicine at the University of Kentucky College of Medicine, said that blood pressure reductions of this magnitude would be expected to be accompanied by significant reductions in risk for atherosclerotic cardiovascular disease—without drug side effects. Anderson's most recent findings reinforce an earlier study that found Transcendental Meditation produces a statistically significant reduction in high blood pressure that was not found with other forms of relaxation, meditation, biofeedback or stress management.

"Adding Transcendental Medication is about equivalent to adding a second antihypertension agent to one's current regimen only safer and less troublesome," Anderson said.

The Centers for Disease Control and Prevention (CDC) estimates that 1 out of 3 American adults have high blood pressure. Having high blood pressure increases one's chances of developing heart disease, stroke, congestive heart failure and kidney disease.

The study appears in the March issue of the American Journal of Hypertension.

Adapted from materials provided by University of Kentucky.

Carbon Capture Strategy Could Lead To Emission-free Cars

2008-02-22T18:31:00.000-08:00

ScienceDaily (Feb. 14, 2008) — Researchers at the Georgia Institute of Technology have developed a strategy to capture, store and eventually recycle carbon from vehicles to prevent the pollutant from finding its way from a car tailpipe into the atmosphere. Georgia Tech researchers envision a zero emission car, and a transportation system completely free of fossil fuels.
Technologies to capture carbon dioxide emissions from large-scale sources such as power plants have recently gained some impressive scientific ground, but nearly two-thirds of global carbon emissions are created by much smaller polluters — automobiles, transportation vehicles and distributed industrial power generation applications (e.g., diesel power generators).

The Georgia Tech team’s goal is to create a sustainable transportation system that uses a liquid fuel and traps the carbon emission in the vehicle for later processing at a fueling station. The carbon would then be shuttled back to a processing plant where it could be transformed into liquid fuel. Currently, Georgia Tech researchers are developing a fuel processing device to separate the carbon and store it in the vehicle in liquid form.

“Presently, we have an unsustainable carbon-based economy with several severe limitations, including a limited supply of fossil fuels, high cost and carbon dioxide pollution,” said Andrei Fedorov, associate professor in the Woodruff School of Mechanical Engineering at Georgia Tech and a lead researcher on the project. “We wanted to create a practical and sustainable energy strategy for automobiles that could solve each of those limitations, eventually using renewable energy sources and in an environmentally conscious way.”

Little research has been done to explore carbon capture from vehicles, but the Georgia Tech team outlines an economically feasible strategy for processing fossil or synthetic, carbon-containing liquid fuels that allows for the capture and recycling of carbon at the point of emission. In the long term, this strategy would enable the development of a sustainable transportation system with no carbon emission.

Georgia Tech’s near-future strategy involves capturing carbon emissions from conventional (fossil) liquid hydrocarbon-fueled vehicles with an onboard fuel processor designed to separate the hydrogen in the fuel from the carbon. Hydrogen is then used to power the vehicle, while the carbon is stored on board the vehicle in a liquid form until it is disposed at a refueling station. It is then transported to a centralized site to be sequestered in a permanent location currently under investigation by scientists, such as geological formations, under the oceans or in solid carbonate form.

In the long-term strategy, the carbon dioxide will be recycled forming a closed-loop system, involving synthesis of high energy density liquid fuel suitable for the transportation sector.

Georgia Tech settled on a hydrogen-fueled vehicle for its carbon capture plan because pure hydrogen produces no carbon emissions when it is used as a fuel to power the vehicle. The fuel processor produces the hydrogen on-board the vehicle from the hydrocarbon fuel without introducing air into the process, resulting in an enriched carbon byproduct that can be captured with minimal energetic penalty. Traditional combustion systems, including current gasoline-powered automobiles, have a combustion process that combines fuel and air — leaving the carbon dioxide emissions highly diluted and very difficult to capture.

“We had to look for a system that never dilutes fuel with air because once the CO2 is diluted, it is not practical to capture it on vehicles or other small systems,” said David Damm, PhD candidate in the School of Mechanical Engineering, the lead author on the paper and Fedorov’s collaborator on the project.

The Georgia Tech team compared the proposed system with other systems that are currently being considered, focusing on the logistic and economic challenges of adopting them on a global scale. In particular, electric vehicles could be part of a long-term solution to carbon emissions, but the team raised concerns about the limits of battery technology, including capacity and charging time.

The hydrogen economy presents yet another possible solution to carbon emissions but also yet another roadblock — infrastructure. While liquid-based hydrogen carriers could be conveniently transported and stored using existing fuel infrastructure, the distribution of gaseous hydrogen would require the creation of a new and costly infrastructure of pipelines, tanks and filling stations.

The Georgia Tech team has already created a fuel processor, called CO2/H2 Active Membrane Piston (CHAMP) reactor, capable of efficiently producing hydrogen and separating and liquefying CO2 from a liquid hydrocarbon or synthetic fuel used by an internal combustion engine or fuel cell. After the carbon dioxide is separated from the hydrogen, it can then be stored in liquefied state on-board the vehicle. The liquid state provides a much more stable and dense form of carbon, which is easy to store and transport.

The Georgia Tech paper also details the subsequent long-term strategy to create a truly sustainable system, including moving past carbon sequestration and into a method to recycle the captured carbon back into fuel. Once captured on-board the vehicle, the liquid carbon dioxide is deposited back at the fueling station and piped back to a facility where it is converted into a synthetic liquid fuel to complete the cycle.

Now that the Georgia Tech team has come up with a proposed system and device to produce hydrogen and, at the same time, capture carbon emissions, the greatest remaining challenge to a truly carbon-free transportation system will be developing a method for making a synthetic liquid fuel from just CO2 and water using renewable energy sources, Fedorov said. The team is exploring a few ideas in this area, he added.

The research was published in Energy Conversion and Management . The research was funded by NASA, the U.S. Department of Defense NDSEG Fellowship Program and Georgia Tech’s CEO (Creating Energy Options) Program.

Adapted from materials provided by Georgia Institute of Technology.

Solar Cell Directly Splits Water To Produce Recoverable Hydrogen

2008-02-22T18:21:00.000-08:00

ScienceDaily (Feb. 19, 2008) — Plants trees and algae do it. Even some bacteria and moss do it, but scientists have had a difficult time developing methods to turn sunlight into useful fuel. Now, Penn State researchers have a proof-of-concept device that can split water and produce recoverable hydrogen.

"This is a proof-of-concept system that is very inefficient. But ultimately, catalytic systems with 10 to 15 percent solar conversion efficiency might be achievable," says Thomas E. Mallouk, the DuPont Professor of Materials Chemistry and Physics. "If this could be realized, water photolysis would provide a clean source of hydrogen fuel from water and sunlight."

Although solar cells can now produce electricity from visible light at efficiencies of greater than 10 percent, solar hydrogen cells -- like those developed by Craig Grimes, professor of electrical engineering at Penn State -- have been limited by the poor spectral response of the semiconductors used. In principle, molecular light absorbers can use more of the visible spectrum in a process that would mimic natural photosynthesis. Photosynthesis uses chlorophyll and other dye molecules to absorb visible light.

So far, experiments with natural and synthetic dye molecules have produced either hydrogen or oxygen-using chemicals consumed in the process, but have not yet created an ongoing, continuous process. Those processes also generally would cost more than splitting water with electricity. One reason for the difficulty is that once produced, hydrogen and oxygen easily recombine. The catalysts that have been used to study the oxygen and hydrogen half-reactions are also good catalysts for the recombination reaction.

Mallouk and W. Justin Youngblood, postdoctoral fellow in chemistry, together with collaborators at Arizona State University, developed a catalyst system that, combined with a dye, can mimic the electron transfer and water oxidation processes that occur in plants during photosynthesis. They reported the results of their experiments at the annual meeting of the American Association for the Advancement of Science, Feb. 17 in Boston.

The key to their process is a tiny complex of molecules with a center catalyst of iridium oxide molecules surrounded by orange-red dye molecules. These clusters are about 2 nanometers in diameter with the catalyst and dye components approximately the same size. The researchers chose orange-red dye because it absorbs sunlight in the blue range, which has the most energy. The dye used has also been thoroughly studied in previous artificial photosynthesis experiments.

They space the dye molecules around the center core leaving surface area on the catalyst for the reaction. When visible light strikes the dye, the energy excites electrons in the dye, which, with the help of the catalyst, can split the water molecule, creating free oxygen.

"Each surface iridium atom can cycle through the water oxidation reaction about 50 times per second," says Mallouk. "That is about three orders of magnitude faster than the next best synthetic catalysts, and comparable to the turnover rate of Photosystem II in green plant photosynthesis." Photosystem II is the protein complex in plants that oxidizes water and starts the photosynthetic process.

The researchers impregnated a titanium dioxide electrode with the catalyst complex for the anode and used a platinum cathode. They immersed the electrodes in a salt solution, but separated them from each other to avoid the problem of the hydrogen and oxygen recombining. Light need only shine on the dye-sensitized titanium dioxide anode for the system to work. This type of cell is similar to those that produce electricity, but the addition of the catalyst allows the reaction to split the water into its component gases.

The water splitting requires 1.23 volts, and the current experimental configuration cannot quite achieve that level so the researchers add about 0.3 volts from an outside source. Their current system achieves an efficiency of about 0.3 percent.

"Nature is only 1 to 3 percent efficient with photosynthesis," says Mallouk. "Which is why you can not expect the clippings from your lawn to power your house and your car. We would like not to have to use all the land area that is used for agriculture to get the energy we need from solar cells."

The researchers have a variety of approaches to improve the process. They plan to investigate improving the efficiency of the dye, improving the catalyst and adjusting the general geometry of the system. Rather than spherical dye catalyst complexes, a different geometry that keeps more of the reacting area available to the sun and the reactants might be better. Improvements to the overall geometry may also help.

"At every branch in the process, there is a choice," says Mallouk. "The question is how to get the electrons to stay in the proper path and not, for example, release their energy and go down to ground state without doing any work."

The distance between molecules is important in controlling the rate of electron transfer and getting the electrons where they need to go. By shortening some of the distances and making others longer, more of the electrons would take the proper path and put their energy to work splitting water and producing hydrogen.

The U.S. Department of Energy supported this research.

Adapted from materials provided by Penn State.

'NMR On A Chip' Features NIST Magnetic Mini-sensor

2008-02-22T18:14:00.000-08:00

ScienceDaily (Feb. 19, 2008) — A super-sensitive mini-sensor developed at the National Institute of Standards and Technology (NIST) can detect nuclear magnetic resonance (NMR) in tiny samples of fluids flowing through a novel microchip. The prototype chip device, developed in a collaboration between NIST and the University of California, may have wide application as a sensitive chemical analyzer, for example in rapid screening to find new drugs.
The NMR chip detected magnetic signals from atomic nuclei in tap water flowing through a custom silicon chip that juxtaposes a tiny fluid channel and the NIST sensor. The Berkeley group recently co-developed this "remote NMR" technique for tracking small volumes of fluid or gas flow inside soft materials such as biological tissue or porous rock, for possible applications in industrial processes and oil exploration. The chip could be used in NMR spectroscopy, a widely used technique for determining physical, chemical, electronic and structural information about molecules. NMR signals are equivalent to those detected in MRI (magnetic resonance imaging) systems

Berkeley scientists selected the NIST sensor, a type of atomic magnetometer, for the chip device because of its small size and high sensitivity, which make it possible to detect weak magnetic resonance signals from a small sample of atoms in the adjacent microchannel. Detection is most efficient when the sensor and sample are about the same size and located close together, lead author Micah Ledbetter says. Thus, when samples are minute, as in economical screening of many chemicals, a small sensor is crucial, Ledbetter says.

Its small size and extreme sensitivity make the NIST sensor ideal for the microchip device, in contrast to SQUIDs (superconducting quantum interference devices) that require bulky equipment for cooling to cryogenic temperatures or conventional copper coils that need much higher magnetic fields (typically generated by large, superconducting magnets) like those in traditional MRI.

The results reported in the PNAS* demonstrate another use for the NIST mini-sensor, a spin-off of NIST's miniature atomic clocks. The sensor already has been shown to have biomedical imaging applications.

*Journal reference: M.P. Ledbetter, I.M. Savukov, D. Budker, V. Shah, S. Knappe, J. Kitching, D. Michalak, S. Xu , and A. Pines. Zero-field remote detection of NMR with a microfabricated atomic magnetometer. Proceedings of the National Academy of Sciences, posted online Feb. 6, 2008.

The principal investigator for the study described in PNAS is Alexander Pines, a leading authority on NMR. A joint university/NIST patent application is being filed for the microchip device. The research was supported by the Office of Naval Research, U.S. Department of Energy, a CalSpace Minigrant and the Defense Advanced Research Projects Agency.

Adapted from materials provided by National Institute of Standards and Technology.