Nature: Transistors are the basic element of modern electronics. The devices serve as basic on/off logic gates controlled by a small amount of voltage. They are reliable, but maintaining the voltage consumes power. What’s more, because transistors must be hardwired, they require dedicated circuitry. A team of researchers led by Sungjung Joo of the Korea Institute of Science and Technology in Seoul, South Korea, has now created a magnetically controlled transistor that may overcome many of the drawbacks of traditional transistors. The team created a two-layer bridge out of the semiconductor indium antimonide. The top layer is filled with electrons and the lower layer is covered by positively charged “holes.” Depending on the direction of a magnetic field applied perpendicular to the bridge, electrons either flow through the upper layer or are forced into the holes in the lower layer. The ability to direct the magnetic field can be used to enable or disable sections of circuitry and thus “reprogram” the overall circuit to perform different functions. Although such transistors would be useful in any number of technologies, indium antimonide is difficult to incorporate into standard circuit manufacturing processes.
BBC: To estimate the mass of a black hole, astronomers look at the movement of the stars or plasma around it. But the method is time-consuming and inaccurate because of the random motions of the bodies being measured. Timothy Davis of the European Southern Observatory and his colleagues have developed a new technique that uses images of microwave radiation emitted by cold clouds of carbon monoxide gas. Because the gas is cold, the random, thermal motions are less vigorous, resulting in less blurring of the images. And because the images are in the microwave part of the spectrum, they are at higher resolution than previous measurements in the radio. Davis’s team used California’s Combined Array for Research in Millimeter-wave Astronomy to map the movements of particles at various distances from a black hole in NGC 4526. The researchers calculated the black hole to have a mass 450 million times the mass of our sun. Davis believes that the next generation of microwave telescopes will provide even clearer measurements and will significantly reduce the time it takes to make similar calculations.
New Scientist: To the ever-expanding field of video gaming, researchers in Germany have added a new twist: electrical muscle stimulation (EMS). Using two small wired electrodes attached to the gamer’s forearm, EMS sends strong, painless contractions to the hands. The user reflexively fights the contraction, which makes him or her feel more a part of the action. Such haptic technology, which provides tactile feedback to the user, has been likened to the visual enhancement of computer graphics. The mobile force-feedback device will be demonstrated at the Conference on Human Factors in Computing Systems in Paris in April.
Science: Although ibirds and other animals have been known for some time to use low-frequency background noise, or infrasound, to get around, until recently no one knew exactly how it worked. Infrasound can be generated either from natural events, such as deep ocean waves or earthquakes, or from human-made events, such as the acceleration of a supersonic plane. The low-level sound waves created by these events travel long distances and reverberate off the land and the atmosphere. To try to understand how birds can use the sound waves to orient themselves, Jonathan Hagstrum of the US Geological Survey studied data on homing pigeons from three sites near Ithaca, New York, where researchers at Cornell University had conducted extensive releases between 1968 and 1987. Birds released from the Jersey Hill site almost always got lost, whereas birds released from the other two sites did not. Hagstrum concluded that Jersey Hill’s terrain interrupted sound transmission. He also found that short-term atmospheric conditions—a temperature inversion, for example—can temporarily affect infrasound transmittal in an area and thus interfere with animals’ ability to find their way.
Ars Technica: Neutral particles are much harder to accelerate than charged particles for the very reason that researchers want to accelerate them—they don’t respond to electric and magnetic fields. A team of researchers led by R. Rajeev of the Tata Institute of Fundamental Research in Mumbai, India, has adapted laser plasma acceleration for use with neutral particles. Rajeev’s team began by using high-energy laser pulses to accelerate atoms and strip off their electrons, which left behind a plasma of positively charged ions moving in coherent waves. The researchers then created a slow-moving beam of so-called Rydberg atoms, whose outer electrons are loosely bound to their nuclei. Next, the team introduced the Rydberg atoms into the already-accelerated beam of fast-moving ions. When the two types of particles collided, the Rydberg atoms transferred their electrons to the ions. Separating out any residual ions left the researchers with a beam of neutral atoms with MeV energies, a billion times greater than had been achieved by previous neutral-particle accelerators. The atom accelerator is much less powerful than ion accelerators, but being only desktop-sized, it has a wider range of potential applications such as in nanolithography and further studies of plasma behaviors.
Chronicle of Higher Education: A survey of more than 40 professors at three research universities has found that internet- and computer-based technologies such as PowerPoint, YouTube, and online portals are often used to handle logistical problems, such as managing larger class sizes, rather than to improve learning itself. The study also found that there’s a gap between the way universities market technology use in the classroom and the ways that professors actually use the technologies. Although universities tend to present technology as a way to improve teaching, many professors see it instead as a detriment to learning. One professor indicated that students are less likely to attend classes that rely on PowerPoint slides and online course notes because all of the material covered in the course is already available to them.
BBC: Launched earlier today, the Korea Space Launch Vehicle-1 reached its target altitude and successfully deployed a weather satellite designed to collect climate data. The satellite is expected to make contact with the ground station tomorrow. Although South Korea already has several satellites in space, this launch marks an important milestone: It is the first to have taken place on native soil. The launch comes a month after a controversial satellite launch by the North Koreans, which was condemned by the United Nations for violating a ban on missile technology.
Nature: In his second inaugural address, President Obama announced a renewed commitment to addressing climate change, writes Jeff Tollefson for Nature. Despite efforts during his first term to reduce greenhouse gas emissions, much of the reduction was the result of the slow economy and the shift by power companies from burning coal to natural gas. One of the major ways Obama is expected to foment change is by imposing new regulations on power plants, which are responsible for about 40% of US emissions. In addition, three department heads key to the climate agenda—Steven Chu of the Department of Energy, Lisa Jackson of the Environmental Protection Agency, and Jane Lubchenco of the National Oceanic and Atmospheric Administration—are retiring, and Obama’s choices to replace them could further his climate agenda in the face of a still-divided Congress.
Science News: A severely autistic 13-year-old boy received experimental treatment that involved the implantation of electrodes in his brain. A team of doctors led by Volker Sturm of the University Hospital of Cologne in Germany targeted several areas of the boy’s brain and found that stimulation of part of the amygdala—an area connected to emotion and memory—significantly improved his condition. Prior to beginning treatment, the boy was prone to injure himself, did not make eye contact, often woke up screaming, and couldn’t talk. After eight weeks of therapy, his autism symptoms improved, and his level of irritability changed from “severely ill” to “moderately ill.” After six months, he began to use simple words. Sturm’s team believes that the brain stimulation was directly connected to the improvement. After 44 weeks of treatment, the batteries in the device died. It took a month to get them replaced, and during that time, the boy’s condition worsened. Once new batteries were installed, he began improving again. Nevertheless, until deep brain stimulation can be studied in a larger population, the treatment remains experimental for autism and other neurological disorders.
Los Angeles Times: While Japan and several other earthquake-prone countries have already developed early warning systems, the US has been slow to follow suit. Now a group of geophysicists and seismologists has announced a plan to install such a system in Southern California, which is at risk because of the San Andreas Fault. The plan, which would cost $80 million, calls for sensors to be placed in the ground to detect the first signs of an earthquake. Because earthquakes consist of two sets of waves, the system could send out a warning via computers and cellphones when the first waves—called P waves—hit, so that people and businesses would have a few seconds to prepare for the slower moving but potentially more damaging S waves.