Science

In football there are few plays more thrilling than a last-second field goal attempt: both teams line up with the clock one or two ticks from zero. The ball is snapped and the crowd roars as the kicker charges forward in an effort to drive the ball through the yellow uprights, the fate of his team hanging in the balance. Yet why do some kickers rise to the challenge whereas others choke under pressure? It may have more to do with their mental state than physical ability, one psychologist says. “Choking” is a term that has seeped into the vernacular to describe those big moments when athletes—or any individuals in a stressful situation—are unable to perform well under pressure. Choking, however, has little to do with failing to pull off the unbelievable (a 60-yard field goal in a blizzard, for example) nor does it describe a random off-day, performance-wise. Rather, Sian Beilock, a neuroscientist who …

Fully charged: the atomtronic battery in action A battery-like device that supplies a current of ultracold atoms has been created by physicists at the University of Colorado in Boulder. Their “atomtronic” battery is based on a Bose-Einstein condensate (BEC) and could be used to supply circuits made from transistors and other components that operate using atomic rather than electronic currents. Potential applications of the battery include inertial sensing and quantum-information processing. Atomtronics is a new field of applied physics that aims to create analogue and logical circuits using currents of atoms. According to Boulder’s Dana Anderson, “practical devices do not yet exist”, and his team is focused on developing an atom transistor and simple transistor circuits. In 2016 Anderson and colleagues reported the development of an atomtronic transistor based on a magneto-optical trap that contains three potential energy wells. Now, Anderson, Seth Caliga and Cameron Straatsma have created an atomtronic battery that, in principle, could …

Sharks and their relatives face an existential crisis unprecedented in their 420 million years on the planet. A global trade in products from these animals fuels the capture of tens of millions of individuals a year. Strong demand combined with poor fishery regulation and high levels of incidental catch have resulted in many populations being overfished, with some now facing extinction. Many activists argue a total ban on shark fishing is the only solution to slow or halt the decline. But a 2016 study found the majority of shark researchers surveyed believe sustainable shark fisheries are possible and preferable to widespread bans. Many reported they knew of real-world examples of sustainable shark fisheries. But a global roundup of empirical data exploring which species are being fished sustainably was lacking. New research, appearing in the February 6 issue of Current Biology, is filling that gap, and the findings bolster the idea that around the world, some …

Heat, not humidity: four evaporation devices power an LCD
 The power supply has been built by a team led by Wanlin Guo at Nanjing University and Jun Zhou at Huazhong University. It involved depositing multi-walled carbon nanotubes (MWCNTs) onto a quartz substrate to create two electrodes. The substrate is about 25 mm long and the 2 mm electrodes are positioned at each end. Carbon black – tiny particles of carbon about 20 nm in diameter – was then deposited, covering the substrate to a thickness of about 70 µm. Copper wires were then attached to each electrode and a circuit was completed via a voltmeter. Dunked in water One end of the device is placed in a beaker of deionized water so that the bottom few millimetres of the device are immersed. Capillary action draws water up the previously dry portion of the device, reaching a maximum distance of about 20 mm from the wet end in about 1 h. As …

Related images(click to enlarge) That’s the ques­tion that North­eastern researchers, led by assis­tant pro­fessor David Choffnes, ask in new research that explores how free app- and web- based ser­vices on Android and iOS mobile devices com­pare with respect to pro­tecting users’ privacy. In par­tic­ular, the team inves­ti­gated the degree to which each plat­form leaks per­son­ally iden­ti­fi­able information–ranging from birth­dates and loca­tions to passwords–to the adver­tisers and data ana­lytics com­pa­nies that the ser­vices rely on to help finance their operations. The answer? “It depends,” says Choffnes, a mobile sys­tems expert in the Col­lege of Com­puter and Infor­ma­tion Sci­ence. “We expected that apps would leak more iden­ti­fiers because apps have more direct access to that infor­ma­tion. And overall that’s true. But we found that typ­i­cally apps leak just one more iden­ti­fier than a web­site for the same ser­vice. In fact, we found that in 40 per­cent of cases web­sites leak more types of infor­ma­tion than apps.” Those …

Related images(click to enlarge) A team of chemists has developed a method to yield highly detailed, three-dimensional images of the insides of batteries. The technique, based on magnetic resonance imaging (MRI), offers an enhanced approach to monitor the condition of these power sources in real time. “One particular challenge we wanted to solve was to make the measurements 3D and sufficiently fast, so that they could be done during the battery-charging cycle,” explains NYU Chemistry Professor Alexej Jerschow, the paper’s senior author. “This was made possible by using intrinsic amplification processes, which allow one to measure small features within the cell to diagnose common battery failure mechanisms. We believe these methods could become important techniques for the development of better batteries.” The work, described in Proceedings of the National Academy of Sciences, focuses on rechargeable Lithium-ion (Li-ion) batteries, which are used in cell phones, electric cars, laptops, and many other electronics. Many see lithium metal …

Liquid crystals are strange substances, both fish and fowl. They can flow like a liquid, but have the orderly molecular structure of a crystalline solid. And that internal structure can be changed by small cues from outside. A group of scientists at the University of Chicago’s Institute for Molecular Engineering has found a way to exploit this property to turn liquid crystals into a tool to manipulate the shape of synthetic cell membranes. The technique has potential for use in biology, medicine, and advanced materials development. The team reported its findings in the Aug. 10, 2016 edition of Science Advances. “What we’ve done is reproduced the beginnings of cell division in a synthetic system,” said Juan de Pablo, Liew Family Professor in Molecular Engineering, who headed the group. When a cell divides, the spherical cell membrane stretches into an elliptical form, develops a waist in the middle, and then splits into two spherical cells. The …

Related images(click to enlarge) Two papers published by an assistant professor at the University of California, Riverside and several collaborators explain why the universe has enough energy to become transparent. The study led by Naveen Reddy, an assistant professor in the Department of Physics and Astronomy at UC Riverside, marks the first quantitative study of how the gas content within galaxies scales with the amount of interstellar dust. This analysis shows that the gas in galaxies is like a “picket fence,” where some parts of the galaxy have little gas and are directly visible, whereas other parts have lots of gas and are effectively opaque to ionizing radiation. The findings were just published in The Astrophysical Journal. The ionization of hydrogen is important because of its effects on how galaxies grow and evolve. A particular area of interest is assessing the contribution of different astrophysical sources, such as stars or black holes, to the budget …

For the first time, scientists know what happens to a virus’ shape when it invades a host cell, thanks to an experiment by researchers at Penn State College of Medicine and University of Pittsburgh School of Medicine. Understanding how the virus shape changes could lead to more effective anti-viral therapies. The experiment was designed to investigate how a virus’ protein shell — its capsid — changes as it prepares to inject its genetic material into a cell. These altered virus particles are known as A-particles, or virus entry intermediates. In previous experiments, exposing a virus to extreme heat or proteins caused the shape of the entire capsid to change. These were the closest observable simulations to a virus invading a cell that had been devised at the time. “Using these lab tricks, my lab and those of other researchers were able to create high-resolution structures of the altered virus particles, but all of these tricks …

Related images(click to enlarge) After Tropical Depression 19W moved ashore in central Vietnam NASA-NOAA’s Suomi NPP satellite passed over the system and found some powerful thunderstorms over Thailand, Vietnam and Laos capable of dropping heavy rainfall. Tropical depression 19W was renamed Tropical Depression Rai before it made landfall in central Vietnam. At 5 p.m. EDT (2100 UTC) on Sept. 12, the Joint Typhoon Warning Center (JTWC) issued their final bulletin on Rai. At that time, it was 41 miles southeast of Da Nang, Vietnam, near 15.3 degrees north latitude and 108.8 degrees east longitude. Rai had maximum sustained winds near 30 knots (34.5 mph/55.5 kph) and was moving to the west-northwest at 11 knots. On Sept. 13 at 2:50 a.m. EDT (0650 UTC) NASA-NOAA’s Suomi NPP satellite passed over Tropical Depression Rai and measured cloud-top temperatures. The Visible Infrared Imaging Radiometer Suite (VIIRS) instrument aboard NASA-NOAA’s Suomi NPP satellite captured an infrared image of the …

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