Physics Today Daily Edition

Subscribe to Physics Today Daily Edition feed
Please follow the links to view the content.
Updated: 4 days 10 hours ago

Frequently asked questions about networking

6 November 2014
Career coach Alaina G. Levine offered STEM career networking advice in her recent webinar.

fMRI reveals brain's parallel processing structure

6 November 2014

MIT Technology Review: The brain is often referred to as a parallel computer because it can run many different processes simultaneously. Harris Georgiou of the National Kapodistrian University of Athens in Greece and his colleagues have now used functional magnetic resonance imaging (fMRI) to determine how many independent processes are running and on what scale. In Georgiou's experiment, the fMRI scanner represented the brain as a 60 × 60 × 30 grid of 3D voxels, with each voxel embodying roughly 3 million neurons and each neuron having tens of thousands of connections to its neighbors. In comparison, current attempts to model brain functionality use computer chips containing only about 1 million neurons, each with just 256 connections. Using oxygenation in each voxel as a measure of neuronal activity, Georgiou's group studied the brains of test subjects performing visuo-motor and reasoning activities of differing difficulties. The fMRI revealed that complex visuo-motor tasks activated roughly 50 sections of the brain at a level of structure above that of individual neurons.

Securing medical devices against cyberattacks

6 November 2014

Telegraph: The ability of modern medical devices, such as pacemakers, to wirelessly connect to computers has allowed doctors and other medical professionals to more easily monitor them. However, US security experts say that such accessibility could also make them easy prey for terrorists. According to the Department of Homeland Security, there are some 300 medical devices on the market today that have unchangeable passwords. That lack of security could allow a person with malicious intent to gain access and change the settings, perhaps to send a series of shocks to accelerate the heartbeat and cause a fatal arrhythmia or to prevent the device from functioning properly. Besides the development of noise shields and other methods of blocking access, software is being written to look out for any unusual activity or tampering. So far there have been no reports of deaths or injuries caused by such a bodily cyberattack.

Plasma wakefield acceleration provides efficient linear particle acceleration

6 November 2014

Nature: The process of plasma wakefield acceleration was first proposed 30 years ago but has only recently become technically feasible. Now, Michael Litos of SLAC's National Accelerator Laboratory in Menlo Park, California, and his colleagues have built a functioning accelerator capable of producing an energy gain per unit of length that is 1000 times higher than even the Large Hadron Collider at CERN. The technique fires paired bunches of electrons into plasmas. As the first bunch of electrons enters the plasma, its charge pushes the electrons in the plasma away from the beam path, which creates a positively charged channel. That area pulls the plasma electrons back toward the center and, in doing so, accelerates the second bunch of electrons that is following behind the first. The technique works only for linear accelerators, which means it could be adapted to shrink the proposed International Linear Collider from 30 km in length to just 4.5 km. Smaller accelerators would also be able to be easily installed at universities and even hospitals where they could be used for medical imaging.

Extragalactic Rydberg atoms

6 November 2014
Carbon atoms with quantum numbers as high as 508 have been spotted in galaxy M82.

Creationist lab tech sues university, alleging wrongful dismissal

5 November 2014

Nature: A microscopist fired from his job at California State University, Northridge, is now suing the university, claiming wrongful termination. Mark Armitage says that he lost his job because of his belief in creationism. In 2012 he unearthed a fossil triceratops horn in Montana that contained not only fossilized bone but also soft tissue. The discovery of the soft tissue led him to date the specimen as being just thousands of years old—which would place it at the time of the biblical flood—rather than the millions of years supported by most evolutionary biologists. Although he refrained from stating his views on the age of the fossil in his paper, which was published in 2013 in the journal of cell and tissue research Acta Histochemica, he says he was fired because fellow faculty members were upset that a creationist got published in a legitimate scientific journal. Specialists in US labor law say his claim of religious intolerance may not hold up in court.

Mysterious object near center of Milky Way may be unusual star

5 November 2014

Science: Objects at the center of the Milky Way are obscured by dense clouds of gas and dust. One of those objects, G2, was detected to be on a near-collision course with the supermassive black hole believed to be at the center of the Milky Way. Initial observations suggested that G2 was a gas cloud, so it was expected that, as it neared the black hole, it would be torn apart and release bright radiation. But it didn't. Andrea Ghez of UCLA and her colleagues used the Keck Observatory to study G2 as it passed by the galactic center. Because IR images revealed that G2 had continued along its orbit, Ghez's team concluded that G2 must instead be a large star hidden inside a cloud of dust. Their calculations indicate that the star has a mass twice that of the Sun, but a radius 100 times larger. Other researchers argue that even if G2 were just a cloud of gas, it would have stretched and compressed without any significant release of radiation. Further evidence is likely necessary to clearly prove which hypothesis is correct.

Robot baby penguin penetrates emperor colony

5 November 2014

Los Angeles Times: Although humans have been studying penguins for some time, any interaction with the animals has been shown to cause them stress, resulting in faster heart rates, attempts to escape, and interference with their mating and breeding. So to get a closer look with minimal disruption, a team of researchers at the University of Strasbourg in France decided to try using a small, four-wheeled rover dressed up to look like a fluffy penguin chick. When the rover was tested on a colony of emperor penguins within Adélie Land, it was not only accepted into the colony but was also allowed to huddle with a “crèche” of chicks. The results were promising enough that similar robots may be designed to investigate other kinds of animals, including those that swim or fly.

Fabiola Gianotti to be next director of CERN

5 November 2014

BBC: Fabiola Gianotti, who has served as project leader of the LHC's Atlas collaboration since 2009, has been chosen by CERN's managing council to take over the directorship of the organization in 2016. Gianotti earned her doctorate from the University of Milan, Italy, in 1987 and began working at CERN the same year. She will be the first female director of the international institution. Gianotti will replace Rolf Heuer, who oversaw the beginning of operations at the LHC. Because of her key role in the Atlas collaboration, Gianotti was one of the two researchers who announced the 2012 detection of the Higgs particle.

Neuromorphic chip mimics how brain works

4 November 2014

MIT Technology Review: A computer chip is being developed by HRL Laboratories that uses a series of silicon neurons to transmit, receive, and interpret electrical signals. Its design has been modeled on the small size and energy efficiency of the brain. In a recent test, a prototype, consisting of 576 silicon neurons, was mounted on a tiny drone that was flown into three rooms. Upon entering each room, the chip gathered data from the craft’s optical, ultrasound, and IR sensors. The data triggered a pattern of electrical activity in the neurons that the chip then used to recognize the room again when the drone reentered it. By mimicking the way the brain learns, the chip could allow drones to analyze video and sensor data without human intervention. Such smart sensors could be incorporated into cars, airplanes, and other systems.

Probabilistic reasoning is not dependent on education

4 November 2014

Nature: The extent to which human understanding of probability is innate has been extensively debated. In a new study, Vittorio Girotto of the University IUAV in Venice, Italy, and his colleagues attempted to clarify the issue by comparing the probabilistic reasoning abilities of  formally educated adults with those who had received no formal education. Regardless of education level, the subjects were found to be equally capable of predicting that blue would be the most likely color of chip to be pulled out of a basket containing three blue chips and one green chip. Both groups also correctly predicted that a red shape was the most likely to be drawn from a mix of four red squares, three green circles, and one red circle,  and they all updated their prediction to green when told that the shape being drawn was a circle. Both groups were also equally successful when betting whether two tokens drawn from a mixed collection would be the same color. Girotto's team believes that the way problems are presented to people can affect how successful they are at predicting the outcomes. Whereas written problems were used in earlier studies claiming that people showed no inherent ability with probabilities, Girotto and colleagues used visual tests. Girotto also notes that because he and his team did not take advanced reasoning into account, the results should not be overly generalized.

Quantum coating makes button batteries childproof

4 November 2014

BBC: Each year in the US, more than 3000 button-shaped batteries are ingested, primarily by children. When exposed to the fluids of the digestive system, batteries can release current and set off chemical reactions that can seriously injure or kill the person. To prevent that happening, Jeff Karp of the Brigham and Women's Hospital in Boston and his colleagues have invented a coating that keeps the batteries from generating current unless squeezed. They covered the negative terminal of the battery with a 1-mm-thick layer of silicone laced with small particles of metal and then covered the rest of the battery with a sealant. When the battery is squeezed, the silicone compresses and the metal particles get close enough to allow the electrons from the battery to flow through the material via quantum tunneling. They compared the battery's behavior with that of an uncovered battery by placing each in a beaker of simulated stomach fluid. They also tested the covered battery in the digestive systems of live pigs.

Cutting carbon emissions is the only way to alleviate global warming, says study

4 November 2014

New Scientist: Climate change is becoming an ever-more pressing issue. According to the latest report by the Intergovernmental Panel on Climate Change, the only way to avoid “severe, widespread, and irreversible impacts globally” is to immediately curb carbon dioxide emissions and phase them out almost entirely by 2100 or, at the very least, develop technologies to safely bury them underground, a method called carbon capture and storage. Although a potentially cheaper and easier alternative had been proposed—to reduce other greenhouse gas emissions—a new study shows that the benefits of such a plan have been overestimated, for two reasons. Other greenhouse gases, such as methane, do not accumulate in the atmosphere the way CO2 does. And they tend to be emitted by the same sources as CO2 emissions, such as the burning of fossil fuels. "Science has spoken,” said United Nations secretary general Ban Ki-moon. “Leaders must act. Time is not on our side.”

Noise pollution may disrupt breeding for captive rhinos in urban areas

3 November 2014

BBC: Although landscape and diet have been well researched for most animals in zoos and other types of wildlife centers, noise levels have not. And for some animals, such as the rhinoceros, which can hear sounds at much lower frequencies than humans can, the chronic infrasound of urban environments may be affecting captive animals’ behavior, particularly their breeding and reproduction rates. At the fall meeting of the Acoustical Society of America, Suzi Wiseman of Texas State University and colleagues presented their findings regarding the varying soundscapes of zoos. The researchers have been studying various facilities, both those where rhinos breed well and those where they do not, in order to devise a system of acoustic parameters to improve rhino habitats. They hope their findings will benefit not only endangered species but all animals, wild and domestic, that are experiencing human encroachment.

<em>New York Times</em> op-ed: “Academic science isn’t sexist”

3 November 2014
Scholars say math-based fields today reflect gender fairness, not gender bias.

Trinary system protoplanetary disks reveal clues about planet formation

3 November 2014

Ars Technica: Planet formation is complicated in a single-star system and is even more so in systems with two or more stars. It is thought that in multistar systems, each star will have its own protoplanetary disk of dust, and a larger disk will surround the system. GG Tau A is a trinary system 460 light-years away, and recent observations have revealed some details about how such systems work. Emmanuel Di Folco of the University of Bordeaux in France and his colleagues used the Atacama Large Millimeter/Submillimeter Array (ALMA) to study the system. The primary star in the system, GG Tau Aa, has a disk, while the pair of secondary stars GG Tau Ab1 and GG Tau Ab2 (which orbit each other 35 AU from GG Tau Aa) were not seen to have disks, although previous IR observations suggested they might. ALMA also showed evidence of a larger disk surrounding the system. More importantly, ALMA revealed a flow of material from the outer disk to the disk around GG Tau Aa. Without that transfer of material, the internal disk would likely have fallen apart due to the stars' gravity, long before any planets could have formed. ALMA did not reveal any planets around the three stars, but the images did suggest that a planet may be forming in the surrounding disk. The presence of a protoplanet there could explain why the disk is relatively narrow, with 80% of its mass in a region just 90 AU wide.

German science ministers approve additional R&D and education funding

3 November 2014
Nature: On 30 October, Germany's federal and state science ministers agreed to provide €25.3 billion ($31.6 billion) for research and education over the next six years. The funding is expected to be approved by the federal and state governments on 11 December. The majority of the funding will go to universities, which are experiencing rapid growth and expect to add nearly 400 000 more students by 2020. The ministers also agreed to continue annual increases for research institutions such as the Max Planck Society, the Fraunhofer Society, the Leibniz Association, and the Helmholtz Association of German Research Centres. Funding will also be increased annually at the DFG, the nation's largest agency for university research grants.

Chinese space mission suspended for lack of funding

3 November 2014

Science: China’s proposed KuaFu solar wind observatory has been put on hold indefinitely due to loss of funding and support from its international partners. Both the European Space Agency and the Canadian Space Agency had been collaborating with the Chinese Academy of Sciences (CAS) on the mission to put three satellites in orbit to forecast space weather. Although China has successfully launched more than 100 satellites, KuaFu would have been only the second dedicated to science research. Despite attempts to scale the project down to a single satellite, the CAS has also withdrawn its support in light of the fact that KuaFu is no longer a major international collaboration.

Spontaneous fluctuations in a ferromagnetic film

3 November 2014
Magneto-optical measurements capture the dance of magnetic domain walls.

Nuclear arms cuts could produce huge savings, says report

3 November 2014
US has no need for so many nuclear-armed submarines, bombers, and missiles to ensure its post-cold war security, says Arms Control Association.

Pages