PROVIDENCE, R.I. [Brown University] — Policymakers struggling to stop the spread of HIV grapple with "what if" questions on the scale of millions of people and decades of time. They need a way to predict the impact of many potential interventions, alone or in combination.
Heavens
For theoretical physicist Dima Shepelyansky from the CNRS-University of Toulouse, France, devising models of chaos and turbulence is his bread and butter. In a recent study published in EPJ B¹, he presents an exception he found in a model of turbulence, indicating that there are energy flows from large to small scale in confined space. Indeed, under a specific energy threshold, there are no energy flows, similar to the way electron currents and energy spreading are stopped in disordered solids.
An international team of researchers from the USA and Europe including from the University of Bonn under the direction of Dr. Hugues Sana (University of Amsterdam) has discovered that the most massive stars in the universe don't spend their lives in space as singles as was previously thought. More than two-thirds orbit a partner star. "The orbit paths of the stars are very close together so that the region around these stars is turbulent and by far not as calm as previously thought," says Professor Norbert Langer from the University of Bonn.
The inspiration behind NASA scientist Maxim Markevitch's quest to build a highly specialized X-ray mirror using a never-before-tried technique comes from an unusual source: a roll of Scotch® tape.
Markevitch and a team of X-ray optics experts at NASA's Goddard Space Flight Center in Greenbelt, Md., have begun investigating the feasibility of fashioning a low-cost mirror from plastic tape and tightly rolling it like the sticky adhesive commonly found in most homes and offices.
The Universe is a diverse place, and many stars are quite unlike the Sun. An international team has used the VLT to study what are known as O-type stars, which have very high temperature, mass and brightness [1]. These stars have short and violent lives and play a key role in the evolution of galaxies. They are also linked to extreme phenomena such as "vampire stars", where a smaller companion star sucks matter off the surface of its larger neighbour, and gamma-ray bursts.
A new versatile measurement system devised by researchers at the National Institute of Standards and Technology (NIST) accurately and quickly measures the electric power output of solar energy devices, capabilities useful to researchers and manufacturers working to develop and make next-generation solar energy cells.
Excitation of neurons depends on the selected influx of certain ions, namely sodium, calcium and potassium through specific channels. Obviously, these channels were crucial for the evolution of nervous systems in animals. How such channels could have evolved their selectivity has been a puzzle until now.
In everyday life, smooth pursuit eye movement is used to track moving targets, Lorenceau explains. While people do have the ability to move their eyes in exquisitely sophisticated ways—and in fact our eyes never cease to move—it is normally impossible to control those movements smoothly in any direction.
University Park, Pa. -- Text messaging may offer tweens a quick way to send notes to friends and family, but it could lead to declining language and grammar skills, according to researchers.
Tweens who frequently use language adaptations -- techspeak -- when they text performed poorly on a grammar test, said Drew Cingel, a former undergraduate student in communications, Penn State, and currently a doctoral candidate in media, technology and society, Northwestern University.
Pulsars are superlative cosmic beacons. These compact neutron stars rotate about their axes many times per second, emitting radio waves and gamma radiation into space. Using ingenious data analysis methods, researchers from the Max Planck Institutes for Gravitational Physics and for Radio Astronomy, in an international collaboration, dug a very special gamma-ray pulsar out of data from the Fermi Gamma-ray Space Telescope.
COLLEGE PARK, Md. - History offers a warning, but no clear pattern on the true risk of terrorism at the Olympic Games, concludes a new report by the National Consortium for the Study of Terrorism and Responses to Terrorism (START) based at the University of Maryland.
The Olympic Games have been terror targets on three separate occasions since 1970, claiming 22 lives and wounding more than 100, the report says. It compiles and analyzes data from START's comprehensive Global Terrorism Database (GTD).
GREENBELT, Md. -- Researchers analyzing meteorite fragments that fell on a frozen lake in Canada have developed an explanation for the origin of life's handedness – why living things only use molecules with specific orientations. The work also gave the strongest evidence to date that liquid water inside an asteroid leads to a strong preference of left-handed over right-handed forms of some common protein amino acids in meteorites. The result makes the search for extraterrestrial life more challenging.
Washington, D.C.— Comets and asteroids preserve the building blocks of our Solar System and should help explain its origin. But there are unsolved puzzles. For example, how did icy comets obtain particles that formed at high temperatures, and how did these refractory particles acquire rims with different compositions? Carnegie's theoretical astrophysicist Alan Boss and cosmochemist Conel Alexander* are the first to model the trajectories of such particles in the unstable disk of gas and dust that formed the Solar System.
Rapid intensification of tropical cyclones is still somewhat of a mystery to forecasters, but one marker that NASA scientists confirmed is when "hot towers" appear within a tropical cyclone as they did in Typhoon Vicente before it exploded in strength on July 23. Vicente made landfall in southern China on July 23.