Physics Today Daily Edition
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.
MIT Technology Review: As microchips become smaller, photolithography, the current technique for producing them, is reaching its limits in terms of complexity and expense. A group of researchers at IBM has demonstrated a process of molecular directed self-assembly that may provide a method for making significantly smaller microchips. By carefully preparing a set of block copolymers, and guiding the molecules' positioning using existing photolithography methods, the team was able to create circuit features that were separated by just 29 nm. Current methods are limited to separations of 80 nm. The potential increase in density of microchip circuitry could lead to much smaller chips and significant advances in processing power.
Science: The Doomsday Clock is maintained by the board of the Bulletin of the Atomic Scientists (BAS) as a representation of how close the world is to a global disaster. On 22 January, BAS executive director Kennette Benedict announced that the organization would be moving the clock hands 2 minutes closer to midnight, setting the symbolic time as 11:57pm. Benedict said that the reasons for the change include the recent stalling in nuclear disarmament talks and the growing threat of climate change. The time change is just the 18th since the clock's creation in 1947. It has ranged from just two minutes to midnight in 1953 to 17 minutes to midnight in 1991.