Physics Today Daily Edition
Science: John Culberson (R-TX) is the new chair of the Commerce, Justice, Science (CJS), and Related Agencies spending panel in the US House of Representatives. CJS oversees a large portion of US science research spending, including the funding for NASA, NIST, NSF, and the National Oceanic and Atmospheric Administration. Culberson says that he has had a lifelong passion for science despite his chosen career in law. He also says his desire to support government investment in science does not contravene his fiscal conservatism. However, that support seems to be limited to space science and basic research and does not include the social and behavioral sciences. He says he supports fellow Texas representative Lamar Smith's efforts to focus NSF's research grants on basic science.
Ars Technica: Nitrogen composes about 78% of Earth's atmosphere and is the most common pure element on the planet. However, the nitrogen on Earth does not occur in the same isotope fractions as the nitrogen found in the Sun or in the tails of comets. A new analysis of an ancient meteorite may provide some clues as to where Earth's nitrogen came from. Transmission electron microscopy and secondary ion mass spectrometry reveal that the meteorite contains the mineral carlsbergite. The mineral's characteristics suggest it was formed in the presence of ammonia (NH4), which likely came from ice in the Sun's protoplanetary disk. That ice could later have been part of the material that accreted to form Earth. It is possible that the different isotope ratios of nitrogen found in the Sun and in comets blended in such a way as to produce the nitrogen mix now present on Earth.
MIT Technology Review: Lithium-air batteries have a theoretical energy density 10 times that of current lithium-ion batteries. In a car, they would provide energy comparable to that of a full tank of gas. However, current models are still far from reaching that energy density, and the number of times they can be recharged is limited. Lithium-air batteries work by allowing lithium ions to react with the oxygen in air to create lithium oxide. Recharging them involves breaking back down that molecule. The batteries' ability to be recharged is limited because the lithium oxide tends to bond to one of the battery's electrodes, covering the catalyst that facilitates the breakdown of the lithium oxide. A team of researchers from Yale and MIT has developed a new membrane made of catalyst-coated nanofibers to which the lithium oxide doesn't bond. The extra catalyst increases the battery's energy density and doubles the number of recharge cycles. However, the experimental battery can be recharged only about 60 times before it needs to be replaced. Commercial car batteries should be able to be recharged roughly 1000 times. The battery also uses pure oxygen instead of air because air's carbon dioxide reduces the battery's efficiency.
Nature: Scheduled for launch on 29 January, NASA's Soil Moisture Active Passive satellite will use microwave signals to measure soil-moisture levels everywhere on Earth and to determine whether the soil is frozen. Clear measurements of soil moisture will help improve water availability models, which are important for both urban and rural areas. The data will help insurance companies to improve crop price models and allow scientists to better monitor droughts and other climate trends. The information on frozen and thawed soil can be used by the military for planning troop movements and by scientists for measuring polar melt due to climate change.
MIT Technology Review: Recording neural activity for an entire brain has only ever been done with animals that are held in place. Recordings of unrestrained animals have been limited to small sections of the brain. Now Jeffrey Nguyen of Princeton University and his colleagues have recorded whole-brain activity in swimming nematodes. To do that, they suspended a movable camera system above a petri dish holding a nematode and then used image recognition software to keep the camera focused on the animal's head. Combined with a standard imaging technique that causes neurons to fluoresce when they release calcium ions, which is considered a proxy for neural activity, the system allowed them to record five brain volumes per second.
New Scientist: Previous analysis of the El Niño Southern Oscillation has suggested that warming ocean temperatures are going to cause the number of extreme El Niño events to double in frequency in the 21st century. Now Wenju Cai of the Commonwealth Scientific and Industrial Research Organisation in Melbourne, Australia, and his colleagues have shown that the number of extreme La Niña events is also expected to double. In their analysis, 17 of 21 climate models showed a doubling in frequency, and the average increase across all models was 74%. Cai says it is the uneven heating of the Pacific Ocean that is driving the increasing severity of the two weather patterns. An especially severe El Niño discharges larger amounts of energy from equatorial waters, which allows larger areas of cold water to rise to the surface. The lower temperatures at the ocean surface drive La Niñas.
Nature: On 23 January the US National Research Council released a report on NSF's ocean sciences division. In 2013 the division began spending more money on infrastructure than on basic science research, so NSF commissioned the report to seek outside advice. The report recommends that the division drastically reduce what it spends on infrastructure. The biggest target is the $386 million Ocean Observatories Initiative, whose operating budget could be slashed by 20%. The report also suggests a 10% cut to the scientific ocean-drilling program and a 5% cut in NSF's contribution to support its 20-vessel research fleet.
Ars Technica: Historical records of sea levels during the past several million years show periods during which they were as much as 20 m higher than they are currently. However, when fed climate details from the periods of highest sea levels, current computer models do not match the historical record. To attempt to correct the models, David Pollard and Richard Alley of the Pennsylvania State University and Robert DeConto of the University of Massachussetts Amherst added two physical processes not currently included in the models—hydrofracturing and cliff failures. Hydrofracturing occurs when water fills crevasses in ice sheets to such depth that the pressure from the water breaks the ice sheet even further. Cliff failures occur when a cliff of ice becomes so tall that it collapses under its own weight. Both processes can increase the calving of icebergs from ice sheets. When that occurs near the grounding line, it can accelerate the loss of a glacier trapped behind the sheet. The adjusted model predicted a much quicker and more severe loss of ice sheets, which could account for much of the historical sea-level rise.