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Updated: 31 min 12 sec ago

Cold-atom experiment mimics aspect of high-temperature superconductivity

2 March 2015

Science: A team led by Randall Hulet of Rice University in Houston, Texas, has trapped a collection of 100 000 to 250 000 lithium-6 ions in an optical lattice and, using lasers, caused the ions to settle into an antiferromagnetic state—that is, a pattern in which neighboring spins alternate between up and down. The feat is significant because high-temperature superconductivity emerges from a antiferromagnetic state. What's more, Hulet's lattice is a physical embodiment of the Fermi–Hubbard model, a physically simple yet mathematically intractable description of electron–electron interactions. With further experimental advances, Hulet and his team could prove (or disprove) whether the model is sufficient to capture the physics of high-temperature superconductivity.

Cavity gravimetry

2 March 2015
Placed inside an optical cavity, an atom interferometer gains potency and precision.

Democrats call for information from seven climate testifiers’ universities

2 March 2015
Does this “street fight” resemble past conflict between Virginia’s attorney general and climatologist Michael Mann?

LGBT physicists: The interviews

27 February 2015
Scientists talk about their experiences as sexual and gender minorities.

More methane-release craters in Siberia than thought

27 February 2015

Washington Post: Last summer a series of unusual craters—the first more than 30 m across—were found in Siberia. Researchers explained that warming temperatures in the region had caused the layer of permafrost to melt and release bubbles of trapped methane gas. Since then, seven more craters have been found, some of which have become lakes and one of which is surrounded by a collection of mini-craters. Beyond the danger of the methane explosions themselves, the phenomenon is a threat to the region's natural gas fields, which are a major part of the Russian economy. So far, the explosions have not injured anyone, but at least one of them has resulted in a fireball, and there is evidence that methane continues to leak from one of the craters. As Siberia continues to warm—2012 and 2013 were both 5° warmer than the historical average—the threat of these explosions is likely to increase.

Unusual bright reflections spotted on Ceres

27 February 2015

The Guardian: NASA's Dawn spacecraft is traveling toward Ceres, the largest body in the asteroid belt, and is taking pictures of the dwarf planet as it approaches. Some of those recent images have revealed unexpectedly bright reflections from the surface. The brightest spot is reflecting about 40% of the light hitting it. Ice is known to account for roughly one quarter of Ceres's mass, so it is likely that the reflection is caused by patches of exposed ice. Normally the ice is contained below the surface, so its exposure was probably the result of the impact of other asteroids. As Dawn approaches Ceres and the resolution of its photographs improves, if ice is the cause of the reflection, the amount of light being reflected should increase to nearly 100%.

Fukushima study tracks rise and fall of radioactivity in food

27 February 2015

Nature: The tsunami that struck the coast of northeastern Japan on 11 March 2011 inundated the Fukushima Daiichi nuclear plant and led to the biggest release of radioactive material into the environment since Chernobyl. In the wake of the disaster, the Japanese government established an extensive and continuing monitoring campaign to track levels of radiation in the nation's food supply. Stefan Merz of the Vienna University of Technology in Austria and his colleagues have analyzed the almost 900 000 food samples in the campaign database. In 2011, the year of the disaster, Merz's team found that 3.3% of food from the region around the power plant had above-limit contamination. By 2014 the percentage had fallen to 0.6%. Food in the rest of Japan was also contaminated: 0.9% in 2011; 0.2% in 2014.

Computer learns to play classic video games

26 February 2015

BBC: A computer program developed by Google DeepMind has learned how to play 49 classic Atari video games. In about half the games, it was able to match the abilities of a professional human player. What makes this achievement significant is that the program was not specifically designed to play the games. Instead, it was given only the basic information needed to play them: the raw pixels on the screen and the goal of getting a high score. From that information the program could be presented with any of the games and, in the course of a few hours, learn to play the game with varying levels of success.

Surprisingly large quasar dates from very early universe

26 February 2015

Los Angeles Times: An object spotted by the Sloan Digital Sky Survey appears to be a black hole 12 billion solar masses in size. Its redshift suggests it formed when the universe was only 875 million years old. Of the known black holes formed in the universe's first billion years, it is by far the most massive and luminous. This black hole is also a quasar and is pulling in so much of the surrounding material that massive amounts of radiative energy are being released. And that's what makes it unusual. Normally, the pressure from that radiation is expected to gradually slow the rate at which material falls into a black hole. The finding that the black hole reached such a great size in such a short period of time challenges current understanding. Further observations of this black hole could provide more clues into black hole formation and evolution. As the light it emits passes through the material in the intergalactic medium,  which was much denser 13 billion years ago, that light could also provide information about the growth of the universe itself.

Dangling DNA pinpoints a protein's chemical groups

26 February 2015
A short single-stranded nucleic acid chain attached to the tip of an atomic force microscope can locate its complement with high resolution and specificity.

The rise of black soot

25 February 2015
New field research suggests that on the Tibetan plateau the effect of black soot on glacial melting rivals, and may even surpass, the effect of greenhouse gas emissions.

Renewable energy likely to surpass nuclear's contribution to UK power supply

25 February 2015
New Scientist: In 1995, when the last nuclear reactor was built in the UK, nuclear power accounted for more than 25% of the nation's energy production. Now that the government has heavily invested in the addition of renewable energy production, nuclear power produces only 19%. Between 2010 and 2013, renewable energy's contribution increased more than twofold, from 6.8% to 14.9%. Wind turbines have been the main source of that growth. The government has invested £14.5 billion ($22.5 billion) in wind energy since 2010. Onshore and offshore turbines now contribute more than half of the country's renewable energy production. A plan for the world's largest offshore turbine farm was approved last week, and the 400-turbine project is expected to increase offshore production by two-thirds of its current level.

Eyelashes serve as windbreak to shield eye

25 February 2015
New York Times: Once thought to protect the eye by catching dust particles or triggering blinking, eyelashes actually serve to divert airflow away from the eye’s surface. David Hu of Georgia Tech and colleagues measured the lashes of various mammals and found that most lashes tend to be about one-third the eye width. That appears to be the optimal length to channel air away from the ocular surface, which helps to reduce evaporation and the deposition of dust, according to their study published in the Journal of the Royal Society Interface. To test lashes’ ability as a windbreak, the researchers created an artificial eye and placed it in a wind tunnel. They found that the lashes’ aerodynamic benefits decrease with increasing length—longer lashes can actually channel airflow toward the eye’s surface. The principles involved could be used to help reduce dust on sensitive sensors or solar panels.

Record sea-level rise along northeast coast of North America

25 February 2015

BBC: Tidal measurements from 2009 and 2010 reveal that sea levels along the Atlantic coastline north of New York City rose by 128 mm over that two-year period. A team of researchers from the University of Arizona and the National Oceanic and Atmospheric Administration split the Atlantic coastline into three regions, with the other two regions stretching from New York City to Cape Hatteras, North Carolina, and from Cape Hatteras southward. They say the increase in level seen north of New York City was higher than any recorded in the past 100 years and is "a 1-in-850 year event." The rise is likely tied to major storms that lifted tides and had a lasting effect on local sea levels.

Foam on latte inhibits sloshing

25 February 2015
Los Angeles Times: Black coffee carried in a cup is more likely to slosh over the edge than is a foamy latte. To look at the physics involved, Alban Sauret of the French National Center for Scientific Research and his colleagues filled a small rectangular container with water, glycerol, and Dawn dishwashing liquid. They built up several layers of bubbles by using a needle and a syringe pump. When the container was either jolted or set in a gentle, rocking motion, the researchers observed that the foam on top of the liquid “increases the damping coefficient and reduces the amplitude of the free-surface oscillations,” according to their paper published in the journal Physics of Fluids. The findings could have many large-scale, industrial applications, such as improving the transportation of oil and gas in tanker ships. The researchers note that their findings also apply to beer—a very foamy beer, like Guinness, is much less sloshy.

Delayed pay rise prompts hunger strike by Indian PhD students

24 February 2015

Nature: In October 2014, following widespread student protests over low pay and delayed payouts, the Indian government announced an increase in the wages that fellowships pay to the country's PhD students. Some of the government agencies, such as the Department of Science and Technology and the Department of Biotechnology, have already implemented the new wage system. Others have not. At least two, the Ministry of Human Resource Development and the University Grants Commission, have announced that they would implement the changes but have not yet done so, nor have they provided timetables for the changes. The delays and lack of information from the funding agencies have driven thousands of graduate students to launch a hunger strike. On 20 February, about 150 student protesters who went to an office of the human resource development ministry in New Delhi were taken to a police station, which further increased tensions between the students and the government.

US must increase its energy funding, says innovation council

24 February 2015

New York Times: The American Energy Innovation Council is urging the US government to triple its current level of funding for energy research. In the council’s recent report, some of the country’s top business leaders, among them Bill Gates of Microsoft and Jeffrey Immelt of General Electric, say that without dramatically increasing federal funding for technology innovation, the US risks falling behind in the energy race. The US must make more of an effort to both improve existing technologies and create new technologies to provide affordable and sustainable energy to its citizens while limiting greenhouse gas emissions. Safer nuclear reactors, cheaper carbon-capture methods, and better batteries are among the objectives mentioned. Although the report cites some progress on the recommendations the council made five years ago, much more needs to be done. Council members say the upcoming 2016 presidential race may provide some impetus to take up their ambitious recommendations.

Tracking people via their cell phone battery usage

24 February 2015
BBC: Most people know that their phone can be tracked through its GPS, cellular, or Wi-Fi connectivity. That’s why phone applications require the user’s permission to access those services. However, no permission is needed to read the phone’s power consumption, and that information, according to a new study, can also be used to infer a user’s location. The amount of power a phone uses depends on how far it is from a cell phone tower and how many obstacles, such as trees or buildings, are in between. Although phones run many applications simultaneously that also drain the battery, that noise is not correlated with the phone’s location and can be ruled out by a machine learning algorithm. The researchers say that if one knows the general area in which a given user moves, the application can learn information about the user’s location in just a few minutes.

Dragonflies have extraordinary color vision

24 February 2015
New Scientist: Dragonflies apparently surpass all other known animal species in the ability to see color. Whereas the vision of most mammals, birds, and insects is di-, tri,- or tetrachromatic—humans, for example, see colors as a combination of red, green, and blue—dragonflies can detect as many as 30 different vision pigments. Ryo Futahashi of the National Institute of Advanced Industrial Science and Technology in Tsukuba, Japan, and colleagues have also found that the number of opsins, or light-sensitive proteins, can vary over the course of an individual dragonfly’s development, from larva to adult. The extra opsins may also allow dragonflies to see UV and polarized light.

Winds generated by black holes limit galaxy formation

23 February 2015
BBC: Supermassive black holes generate high-velocity winds that blow outward in every direction, according to a new study published in Science. Using two telescopes—NASA’s Nustar, which detects high-energy x rays, and the European Space Agency’s XMM-Newton, which detects lower-energy x rays—Emanuele Nardini of Keel University in the UK and colleagues were able to deduce the speed, shape, and size of the winds by looking at the way iron atoms were scattered. Because the winds eject a considerable amount of material from the host galaxy, fewer stars are able to form from the material that's left.

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