Scientists have reconstructed the past climate for the region around Cantona, a large fortified city in highland Mexico, and found the population drastically declined in the past, at least in part because of climate change. The research appears in the online edition of the Proceedings of the National Academy of Sciences.
In a marathon, everyone starts at roughly the same place at roughly the same time. But the faster runners will gradually increase their lead, and in the end, the distribution of runners on the street will be very broad. Something similar happens to a pulse of light sent through a medium. The pulse is a combination of different colors (or wavelengths), and when they are sent through a medium like glass, they travel at different speeds.
A potential avenue to quantum computing currently generating quite the buzz in the high-tech industry is “valleytronics,” in which information is coded based on the wavelike motion of electrons moving through certain 2-D semiconductors. Now, a promising new pathway to valleytronic technology has been uncovered by researchers with the Lawrence Berkeley National Laboratory.
Friction impacts motion, hence the need to control friction forces. Currently, this is accomplished by mechanistic means or lubrication, but experiments conducted by researchers at Oak Ridge National Laboratory have uncovered a way of controlling friction on ionic surfaces at the nanoscale using electrical stimulation and ambient water vapor.
The idea of computing systems based on controlling atomic spins just got a boost from new research performed at MIT and Brookhaven National Laboratory. By constructing tiny "mirrors" to trap light around impurity atoms in diamond crystals, the team dramatically increased the efficiency with which photons transmit information about those atoms' electronic spin states, which can be used to store quantum information.
Nature packs away carbon in chalk, shells and rocks made by marine organisms that crystallize calcium carbonate. Now, research suggests that the soft, organic scaffolds in which such crystals form guide crystallization by soaking up the calcium like an "ion sponge". Understanding the process better may help researchers develop advanced materials for energy and environmental uses, such as for removing carbon dioxide from the atmosphere.
A new study by Univ. of Kentucky Markey Cancer Center researchers suggests that targeting a key enzyme and its associated metabolic programming may lead to novel drug development to treat lung cancer. Cancer cells undergo metabolic alterations to meet the increased energy demands that support their excess growth and survival.
A new study finds that most climate models likely underestimate the degree of decade-to-decade variability occurring in mean surface temperatures as Earth's atmosphere warms. The models also provide inconsistent explanations of why this variability occurs in the first place. These discrepancies may undermine the models' reliability for projecting the short-term pace as well as the extent of future warming, the study's authors warn.
Using one of the largest supercomputers in the world, a team of researchers led by the Univ. of Minnesota has identified potential materials that could improve the production of ethanol and petroleum products. The discovery could lead to major efficiencies and cost savings in these industries. The Univ. of Minnesota has two patents pending on the research and hopes to license these technologies.
Understanding this electronic effect in organic molecules is crucial for their use in optoelectronic applications. In their article published in Nature Physics, the research team demonstrates measurements on the organic molecule cobalt phthalocyanine (CoPC) that can be explained only by taking into consideration how electrons in the molecule interact with each other.
Graphene has many desirable properties. Magnetism alas is not one of them. Magnetism can be induced in graphene by doping it with magnetic impurities, but this doping tends to disrupt graphene's electronic properties. Now a team of physicists at the Univ. of California, Riverside has found an ingenious way to induce magnetism in graphene while also preserving graphene's electronic properties.
Cancer uses a little-understood element of cell signaling to hijack the communication process and spread, according to Rice Univ. researchers. A new computational study by researchers at the Rice-based Center for Theoretical Biological Physics shows how cancer cells take advantage of the system by which cells communicate with their neighbors as they pass messages to “be like me” or “be not like me.”
Researchers in Japan revealed that improvements should soon be expected in the manufacture of transistors that can be used, for example, to make flexible, paper-thin computer screens. The scientists reviewed the latest developments in research on photoactive organic field-effect transistors, devices that incorporate organic semiconductors, amplify weak electronic signals and either emit or receive light.
Since the beginning of recorded time, humans have used materials found in nature to improve their lot. Since the turn of this century, scientists have studied metamaterials, artificial materials engineered to bend electromagnetic, acoustic and other types of waves in ways not possible in nature. Now, a discovery has been made with these synthetic materials that may take engineers one step closer to building microscopes with superlenses.
Scientists at the Univ. of Liverpool have controlled the structure of a material to simultaneously generate both magnetization and electrical polarization, an advance which has potential applications in information storage and processing. The researchers demonstrated that it's possible to unlock these properties in a material which initially displayed neither by making designed changes to its structure.
Theoretical physicists at Rice Univ. are living on the edge as they study the astounding properties of graphene. In a new study, they figure out how researchers can fracture graphene nanoribbons to get the edges they need for applications. New research shows it should be possible to control the edge properties of graphene nanoribbons by controlling the conditions under which the nanoribbons are pulled apart.
A research team has developed a new technique for determining the role that a material’s structure has on the efficiency of organic solar cells, which are candidates for low-cost, next-generation solar power. The researchers have used the technique to determine that materials with a highly organized structure at the nanoscale are not more efficient at creating free electrons than poorly organized structures.
New laser-driven compression experiments reproduce the conditions deep inside exotic super-Earths and giant planet cores, and the conditions during the violent birth of Earth-like planets, documenting the material properties that determined planet formation and evolution processes. The experimentsreveal the unusual properties of silica under the extreme pressures and temperatures relevant to planetary formation and interior evolution.
Scientists have identified synthetic materials that may purify ethanol more efficiently and greatly improve the separation of long-chain hydrocarbons in petroleum refining. The results show that predictive modeling of synthetic zeolites is highly effective and can help solve some of the most challenging problems facing industries that require efficient ways to separate or catalyze materials.
Univ. of Chicago scientists have experimentally observed, for the first time, a phenomenon in ultracold, three-atom molecules predicted by Russian theoretical physicist Vitaly Efimov in 1970. In this quantum phenomenon, called geometric scaling, the triatomic molecules fit inside one another like an infinitely large set of Russian nesting dolls.
Researchers report the first crystal structure of the cellular receptor CXCR4 bound to an immune signaling protein called a chemokine. The structure, published in Science, answers longstanding questions about a molecular interaction that plays an important role in human development, immune responses, cancer metastasis and HIV infections.
Scientists have proved a fundamental relationship between energy and time that sets a “quantum speed limit” on processes ranging from quantum computing and tunneling to optical switching. The energy-time uncertainty relationship is the flip side of the Heisenberg uncertainty principle, which sets limits on how precisely you can measure position and speed, and has been the bedrock of quantum mechanics for nearly 100 years.
Sound waves passing through the air, objects that break a body of water and cause ripples or shockwaves from earthquakes all are considered “elastic” waves. These waves travel at the surface or through a material without causing any permanent changes to the substance’s makeup. Now, researchers have developed a material that has the ability to control these waves.
Reducing the use of laboratory animals has been a long-term goal in biological research. Many in vivo assays, like rabbit endotoxin testing or mouse antibody production testing to detect viral contaminants have largely been replaced by in vitro enzyme or PCR-based assays.
The creation of genetically modified and entirely synthetic organisms continues to generate excitement as well as worry. Such organisms are already churning out insulin and other drug ingredients, helping produce biofuels and teaching scientists about human disease. While the risks can be exaggerated to frightening effect, modified organisms do have the potential to upset natural ecosystems if they were to escape.