http://phys.org/ en-us PhysOrg Team Phys.org internet news portal provides the latest news on science including: Physics, Nanotechnology, Life Sciences, Space Science, Earth Science, Environment, Health and Medicine. (Phys.org) -- In the phenomenon of superlubricity, two solid surfaces can slide past each other with almost no friction. The effect occurs when the solid surfaces have crystalline structures and their lattices are rotated in such a way as to cancel out the friction force. A bit like stacking two egg cartons, if the lattices are aligned, they lock in to each other and it is hard to slide one over the other. But rotate one egg carton a bit, and it no longer locks in this way. http://phys.org/news258017893.html Nanotechnology 2012-06-04T09:30:01-07:00 (Phys.org) -- Researchers first observed graphene in 2004 by extracting the single-atom-thick sheets of carbon from bulk graphite. While graphene’s electrical and optical properties have proven to have extraordinary potential for many applications, creating atomically precise structures out of graphene remains challenging. In an effort to improve graphene’s usability, scientists have been searching for a way to fabricate artificial graphene, which could serve as a helpful structure where devices can be easily tested before their implementation with natural graphene. Now in a new study, scientists have identified all the main criteria required to make artificial graphene, which could provide a guide for experimentally realizing the material. http://phys.org/news257497866.html Nanotechnology 2012-05-29T09:20:01-07:00 (Phys.org) -- What’s in a name? Quite a bit in climate science, where the term teleconnection refers not to digital communications, but rather to a recurring and persistent large-scale pattern of pressure and circulation anomalies that spans vast geographical areas. Recently, environmental researchers at Yale School of Forestry & Environmental Studies reframed the discussion around the linkages between land changes and underlying urbanization dynamics by introducing urban land teleconnections as a conceptual framework for studying the multivariate nature of these processes in an integrated and productive manner. http://phys.org/news257409175.html Space & Earth 2012-05-28T09:20:01-07:00 (Phys.org) -- The laws of classical electromagnetism that were developed in the 19th century are the same laws that scientists use today. They include Maxwell’s four equations along with the Lorentz law, which describes the force exerted by electric and magnetic fields on charged particles. But Masud Mansuripur, a professor of Optical Sciences at The University of Arizona in Tucson, is now arguing that the Lorentz law of force is incompatible with special relativity and momentum conservation, and should be abandoned. In a recent issue of Physical Review Letters, he has suggested replacing the Lorentz law with a more general expression of electromagnetic force density, such as one developed by Albert Einstein and Jakob Laub in 1908. http://phys.org/news257069877.html Physics 2012-05-24T09:50:01-07:00 (Phys.org) -- An electron’s spin is separate from its motion, and is suitable for use in both highly-precise magnetic sensing as well as a qubit in quantum computing. Recently, scientists at the University of Konstanz in Germany have theoretically investigated the coupling of electron spin in carbon nanotube quantum dots, showing that the carbon nanotube’s nanomechanical vibrations can significantly affect the spin of an electron trapped on it. Moreover, their findings also theoretically show that the carbon nanotube itself can be affected by the electron’s spin. The researchers state that their findings have important implications for magnetic and mass nanosensors, quantum computing and other nanoscale applications. http://phys.org/news256979923.html Physics 2012-05-23T08:50:01-07:00 (Phys.org) -- By taking advantage of graphene’s favorable electrical and optical properties, and then adding an organic dopant, researchers have achieved the highest power conversion efficiency yet for a graphene-based solar cell. The 1.9% power conversion efficiency of the undoped devices increases by more than four times to 8.6% after doping. http://phys.org/news256804344.html Nanotechnology 2012-05-21T08:50:01-07:00 (Phys.org) -- In a tale worthy of Sherlock Holmes, scientists in the School of Chemistry at the University of Bristol, UK have solved a biochemical mystery that had previously proven elusive for 70 years: How the fungus Talaromyces stipitatus produces stipitatic acid (6), which is a tropolone, one of an atypical group of fungal natural products – that is, small molecules produced by genetically encoded pathways – with a seven-carbon ring. (Most natural products, such as cholesterol or phenylalanine, have five or six carbons in rings.) The researchers used a two-part biosynthetic approach – gene deletion and alternate genetic expression – to investigate the molecular pathway in question. http://phys.org/news256546009.html Biology 2012-05-18T07:47:40-07:00 (Phys.org) -- Replacing the need for nimble fingers, researchers have demonstrated how to make origami using light of a specific wavelength. They call the new folding technique photo-origami, and it could potentially be used as a way to manufacture 3D structures. http://phys.org/news255854674.html Physics 2012-05-10T09:10:03-07:00 (Phys.org) -- For the first time, physicists have experimentally demonstrated the interaction of two motionless light pulses. Because the stopped light pulses have a long interaction time, it increases the efficiency with which one photon can switch the path of a second photon. This ability, called photon switching, could have applications in quantum information technologies and photonic circuits, which use light rather than electric currents to manipulate information. Here, the scientists demonstrated an optical switching efficiency that is even higher than the expected limit, and they predict the efficiency can be increased further. http://phys.org/news255683963.html Physics 2012-05-08T09:00:01-07:00 (Phys.org) -- During the 20-year period from 1989 to 2008, 21% of of all stocks listed in US stock markets became bankrupt. Since bankruptcies affect many investors and have played a large role in the recent global financial crisis, predicting bankruptcy before it happens could help some investors avoid large losses. In a new study, a team of physicists has used concepts from statistical physics to identify some characteristic behaviors of pre-bankrupt stocks that differ significantly from stocks that don't become bankrupt. The approach may eventually help investors forecast stock bankruptcies weeks or months in advance. http://phys.org/news255271245.html Other Sciences 2012-05-03T13:41:22-07:00 (Phys.org) -- Finding new connections between different disciplines leads to new – and sometimes useful – ideas. That’s exactly what happened when scientists in the Department of Physics, Queens College, City University of New York (CUNY), in collaboration with City College of CUNY, Purdue University and University of Alberta, leveraged mathematical topology to create an artificially nanostructured anisotropic (exhibiting properties with different values when measured along axes in different directions) metamaterial that can be switched from a non-conductive dielectric state to a medium that behaves like metal in one direction and like a dielectric another. The metamaterial’s optical properties was mapped onto a topological transformation of an ellipsoidal surface into an hyperboloid – and transitioning from one to the other dramatically increases the photon density, resulting in dramatic increase in the light intensity inside the material. The researchers state that by allowing topologically-based manipulation of light-matter interactions, these types of metamaterials could lead to a wide range of photonic applications in solar cells, light emitting diodes, displays, and quantum computing and communications. http://phys.org/news254766287.html Physics 2012-04-28T10:30:01-07:00 (Phys.org) -- At the heart of quantum mechanics lies the wave function, a probability function used by physicists to understand the nanoscale world. Using the wave function, physicists can calculate a system's future behavior, but only with a certain probability. This inherently probabilistic nature of quantum theory differs from the certainty with which scientists can describe the classical world, leading to a nearly century-long debate on how to interpret the wave function: does it representative objective reality or merely the subjective knowledge of an observer? In a new paper, physicists Roger Colbeck of the Perimeter Institute in Waterloo, Ontario, and Renato Renner who is based at ETH Zurich, Switzerland, have presented an argument strongly in favor of the objective reality of the wave function, which could lead to a better understanding of the fundamental meaning of quantum mechanics. http://phys.org/news254575239.html Physics 2012-04-25T12:21:12-07:00 (Phys.org) -- While quantum dot-based light-emitting diodes (QLEDs) are not made of organic materials, they share many of the same advantages as organic LEDs (OLEDs). For instance, both QLEDs and OLEDs outshine semiconductor-based LEDs in terms of their greater flexibility, better color quality, and potential for lower cost since they can be fabricated using a simple process on a large-area substrate. But ever since the first QLEDs were demonstrated in the mid-'90s, about a decade after OLEDs, their performance has lagged behind OLEDs despite ongoing improvements. Now in a new study, a team of researchers from South Korea has designed and demonstrated QLEDs with an improved efficiency and unprecedented brightness that matches the brightness of today's best fluorescent OLEDs. http://phys.org/news254123413.html Nanotechnology 2012-04-20T06:51:14-07:00 (Phys.org) -- Males and females... Mars and Venus... XY and XX chromosomes -- all are common memes. At the same time, the evolution of therian (placental and marsupial) sex chromosomes is less widely understood. More to the point, these arose some 150 million years ago from a pair of autosomes, or non-sex chromosomes. Having appeared, the X and Y chromosomes – both with the same ancestral genes – began diverging, with the Y chromosome evolving into a state in which (except for two small autosomal regions) it never recombines. As a result, the Y chromosome has degenerated, losing most of its genes in the process. On the other hand, the X chromosome does recombine, retains many ancestral genes – and has gained new genes, and evolved new expression patterns, as well. The increased imbalance of X/Y chromosomal loci led to the emergence of loci-specific X chromosome inactivation, which has been seen as compensating for differential gene dosage (the number of copies of a given gene present in a cell or nucleus) by making expression of X-linked genes similar in males and females. Recently, using RNA sequencing, or RNA-seq, data (more precise than previously-analyzed microarray data), scientists in the Laboratoire de Biométrie et Biologie Évolutive, Université Lyon, Centre National de la Recherche Scientifique, in Villeurbanne, France, found support for the hypothesis that XCI acts as a dosage-compensation mechanism. At the same time, the scientists explored the contribution of dosage-sensitive genes to phenotype expression in X aneuploidy – a condition, relatively common in humans, in which one or more extra or missing chromosomes leads to an unbalanced chromosome complement, resulting in conditions such as Turner (X0) and Klinefelter (XXY) syndromes. http://phys.org/news253883337.html Biology 2012-04-18T08:50:01-07:00 (Phys.org) -- In free-space optical communications (FSO), data is wirelessly transmitted by light propagating through open space. Among their applications, FSO systems are used for communications between spacecraft and have the potential to serve as the “last mile” for fiber optics broadband services. However, one challenge they face is that the light sources used to encode the data require power, and a power supply is often limited. Devices that reflect light, called corner cube retroreflectors (CCRs), can overcome this problem because they can transmit data without their own light source, simply by reflecting incident light from a base station. http://phys.org/news253853863.html Technology 2012-04-17T08:40:01-07:00 (Phys.org) -- In optical communication systems, the overall performance depends on the strategy used to transmit photons from one location to another. In previous attempts to optimize this performance, scientists found that there is a trade-off between three transmission strategies: classical communication (measured in bits), quantum communication (measured in qubits), and shared entanglement (measured in ebits). But previous research has also suggested that the benefits of using this knowledge to implement “trade-off coding” strategies were too small and the coding too complex to have practical value. Now in a new study, scientists have found that trade-off coding strategies can in fact have remarkable performance gains when communicating over an optical channel compared with other traditional optical communication strategies. The finding could lead to transmitting classical and quantum information simultaneously at much higher rates than is possible with other techniques. http://phys.org/news253633964.html Physics 2012-04-16T09:00:02-07:00 (Phys.org) -- While factoring an integer is a simple problem when the integer is small, the complexity of factorization greatly increases as the integer increases. When the integer grows to more than 100,000 or so digits, the problem reaches a point at which it becomes too complex to solve using classical computing methods. But quantum computers, with their use of entanglement and superposition, can theoretically factor a number of any size. However, the largest number that has been factored on a quantum processor so far is 21. Now in a new study, physicists have set a new record for quantum factorization by developing the first quantum algorithm that can factor a three-digit integer, 143, into its prime factors, 11 and 13. http://phys.org/news253373526.html Physics 2012-04-11T14:32:42-07:00 (Phys.org) -- Geomag, the popular children's toy, contains small metal spheres that can be magnetically connected with a click to build a variety of towers, bridges, and sculptures. In a new study, scientists have done something similar on the microscale: they've created a new class of spherical colloids that have tiny magnetic patches embedded beneath their surfaces. In the absence of a magnetic field, the colloidal particles can spontaneously form clusters of controlled size and shape. With the application of an external magnetic field, the clusters can unbind and change their geometry, allowing the structures to reconfigure themselves independent of the chemical conditions of the environment. http://phys.org/news253276277.html Chemistry 2012-04-10T12:10:02-07:00 (PhysOrg.com) -- When an optical fiber is bent by 90° or more, the light begins to leak away, posing a problem for fiber optics communications. But by using special lenses that can bend light by not only 90°, but also 180° (i.e., a U-turn) or 360° (i.e., a full loop), scientists may limit light leakage in optical fibers and overcome this problem, not to mention provide a useful material for many other applications. Recently, a team of scientists has theoretically investigated materials for achieving this kind of advanced light control, which could work equally well for sound waves. http://phys.org/news252572239.html Physics 2012-04-02T07:58:00-07:00 (PhysOrg.com) -- The arms race between effective antibiotic prophylaxis and closely related strains or species of bacteria is continually escalating. Bacteria can quickly develop genetic resistance to a range of antibiotic treatments – genes that can spread though horizontal conjugative transfer due to antibiotics used in medicine and animal feed, as well as increasing presence in the environment (for example, water supplies and wastewater seepage). Moreover, this pattern can reach global levels in the emergence of so-called superbugs that can be extremely difficult to treat. Recently, scientists at the Key Laboratory of Risk Assessment and Control for Environment and Food Safety, at the Institute of Health and Environmental Medicine in Tianjin, China investigated the role of nanomaterials in conjugative gene transfer between bacteria. In addition, they studied the mechanisms associated with related morphological, biochemical, and molecular biological changes. They found that nanoalumina (a form of aluminum) in water promotes such transfer of multidrug-resistant genes. They concluded that their findings are important in assessing the environment risk of nanomaterials in the manufacture and deployment. http://phys.org/news252264053.html Nanotechnology 2012-03-30T09:00:01-07:00 (PhysOrg.com) -- Ranging in thickness from a few nanometers to several micrometers, thin films and coatings play a role in a wide variety of applications. The reflective metal layer on a mirror, the coatings on low-emissivity or colored windows, and the thin silicon layers on thin-film solar cells all consist of thin films. When thin films are compressed with enough force, they can buckle and delaminate under compressive stress. Starting from defects, the buckles propagate, delaminating the film substrate interface on their way. Buckles can be straight, circular, or even take the three-dimensional coiled shape of a telephone cord. Although researchers have studied telephone cord buckling in thin films for decades, they still don't fully understand their propagation mechanisms. A new study now sheds some light on this area. http://phys.org/news252050808.html Physics 2012-03-27T08:10:01-07:00 (PhysOrg.com) -- Inflation, the brief period that occurred less than a second after the Big Bang, is nearly as difficult to fathom as the Big Bang itself. Physicists calculate that inflation lasted for just a tiny fraction of a second, yet during this time the Universe grew in size by a factor of 1078. Also during this time, a very important thing occurred: fluctuations in the quantum vacuum appeared, which later resulted in the temperature fluctuations in the cosmic microwave background (CMB) that in turn produced large-scale structures such as galaxies. But in a new study, physicists now think that their understanding of the features of primordial quantum fluctuations – also called the inflationary power spectrum – may require a few small corrections due to currently unknown physics. These new corrections could allow scientists to search for experimental evidence to test a variety of quantum gravity theories, including string theory. http://phys.org/news251976548.html Physics 2012-03-26T11:20:02-07:00 (PhysOrg.com) -- Some physicists today are investigating the possibility of using molecular magnets as information storage units in future quantum computers. Molecular magnets are molecules whose magnetic moments prefer to lie along a particular axis with respect to the molecular structure. They have electron spin structures that can be magnetically tuned to more than one state and, at low temperatures, can retain this state even in the absence of a magnetic field, potentially allowing them to store information. http://phys.org/news251539205.html Physics 2012-03-21T10:10:01-07:00 (PhysOrg.com) -- Scientists know that using supercapacitors in conjunction with batteries could greatly increase the fuel economy of hybrid electric vehicles (HEVs) due to the fact that supercapacitors can recover and supply energy much more quickly than batteries. This ability, for example, allows a supercapacitor to recover all of the energy during hard braking, while a battery would allow the energy to be wasted in frictional braking due to its inability to quickly harvest energy. http://phys.org/news251472534.html Nanotechnology 2012-03-20T14:40:02-07:00 (PhysOrg.com) -- The effort to classify life into various groups has been a bumpy ride. Prior to the 1900s, living things were usually pegged as either plants or animals – period. By the middle of the 20th century, however, it was asserted that this scheme did not adequately represent fungi, bacteria and protists, leading to a five-group classification – Monera (bacteria), Protista, Fungi, Plantae, and Animalia. At roughly the same time, however, a fundamental distinction between prokaryotic bacteria and the four eukaryotic kingdoms (plants, animals, fungi, and protists) based on nuclei, cytoskeleton, internal membranes, and other shared eukaryote characteristics – for example, unlike eukaryotes, their genetic material is not wrapped by a membrane into a separate compartment – was acknowledged, resulting in a different system – and considerable confusion. Then, things changed anew when an entirely new prokaryotic group – the so-called third domain of life, living in high temperatures and producing methane – was discovered in the late 1970s. http://phys.org/news251110329.html Biology 2012-03-16T11:00:01-07:00 (PhysOrg.com) -- While some comics today are still drawn by hand, many modern cartoonists use a variety of digital tools to create comics. But even with the help of these tools, creating comics is a time-consuming task that requires many human hours of work. In a new study, a team of researchers has designed a program that can automatically transform movie scenes into comic strips, without the need for any human intervention. http://phys.org/news250930033.html Technology 2012-03-14T08:30:01-07:00 (PhysOrg.com) -- Quantum correlations have well-known advantages in areas such as communication, computing, and cryptography, and recently physicists have discovered that they may help players competing in zero-sum games, as well. In a new study, researchers have found that a game player who uses an appropriate quantum strategy can greatly increase their chances of winning compared with using a classical strategy. http://phys.org/news250842675.html Physics 2012-03-13T08:50:01-07:00 (PhysOrg.com) -- A key element of both biotechnology and nanotechnology is – perhaps unsurprisingly – computational modeling. Frequently, in silico nanostructure design and simulation precedes actual experimentation. Moreover, the ability to use modeling to predict biomolecular structure lays the foundation for the subsequent design of biomolecules. Historically, the problem has been that most modeling software presents a tradeoff between being general purpose (in being able to model systems at high/atomic resolution) but limited in scope (i.e., only explores a small fraction conformational space around the initial structure). Recently, however, Stanford University scientists have developed an algorithm – implemented in a modeling program known as MOSAICS (Methodologies for Optimization and SAmpling In Computational Studies) – that achieves nanoscale modeling at the resolution required without being limited by the scope/size dilemma. In addition, the researchers successfully modeled – and benchmarked the new computation modeling technique with – RNA-based nanostructures. http://phys.org/news250772901.html Nanotechnology 2012-03-12T13:40:01-07:00 (PhysOrg.com) -- In the future according to robotics researchers, robots will likely fight our wars, care for our elderly, babysit our children, and serve and entertain us in a wide variety of situations. But as robotic development continues to grow, one subfield of robotics research is lagging behind other areas: roboethics, or ensuring that robot behavior adheres to certain moral standards. In a new paper that provides a broad overview of ethical behavior in robots, researchers emphasize the importance of being proactive rather than reactive in this area. http://phys.org/news250768869.html Electronics 2012-03-12T11:01:35-07:00 (PhysOrg.com) -- Some scientists call the cosmological constant the "worst prediction of physics." And when today’s theories give an estimated value that is about 120 orders of magnitude larger than the measured value, it’s hard to argue with that title. In a new study, a team of physicists has taken a different view of the cosmological constant, Λ, which drives the accelerated expansion of the universe. While the cosmological constant is usually interpreted as a vacuum energy, here the physicists provide evidence to support the possibility that the mysterious force instead emerges from a microscopic quantum theory of gravity, which is currently beyond physicists’ reach. http://phys.org/news250150547.html Physics 2012-03-05T08:20:01-07:00