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# News Picks

Physics Today’s online staff summarize the most important and interesting news about science from the world's top media outlets.

There are 85 posts for the selected month (July 2015).

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July 31, 2015 4:52 PM

### US capital is sinking

Science:  Even if water levels don't rise as much as expected over the coming century, Washington, DC, will still suffer additional flooding as the land it's built on sinks 16 cm over the next 100 years. It may eventually be under water as the land drops up to 40 m over the next 80 000 years. The cause is the last ice age, and in particular the Laurentide Ice Sheet, which covered much of northern North America. The sheet's weight pressed down the underlying earth, which pushed up land farther south, such as the Washington, DC, area. When the ice sheets retreated, the land started sinking back down. The details, published in GSA Today, are from sediment core samples that have undergone a new technique using electrons trapped in quartz crystals for dating sediment. Electrons are trapped at a predictable rate when the sediment is underground. When they are exposed, the rate changes. Not everyone agrees with the interpretation, but the findings, if backed up with other evidence, will significantly affect our understanding of the geology of the region.

July 31, 2015 2:11 PM

### Why sugar makes coffee taste good

The Daily Telegraph:  A spoonful of sugar doesn't just mask the bitter taste of caffeine in coffee in a process called caffeine  dimerization; it also changes the chemistry of the drink. Previously, sugar and salt were thought to simply change the water structure of the drink, but new statistical thermodynamics research, published in Food and Function by Seishi Shimizu of York University, has turned this idea on its head. The sugar actually causes the caffeine molecules to clump together, so they have less surface area to stimulate the taste buds. Shimizu tells The Telegraph that such findings "show how complex the study of food is and that we should be conducting research using first principle physics to better understand it."

July 31, 2015 2:10 PM

### Philae comet data perplexes scientists

NaturePhilae, the cometary lander from the European Space Angeny's Rosetta mission, may never be heard from again, but it has provided a wealth of data already,  much of it contrary to expectations. When Philae landed it bounced because the surface was not, as expected, a deep layer of dust. Measurements of the leg compression and from the hammer that was supposed to penetrate the surface have revealed that the comet's surface is a hard crust covered in areas with thin layers of dust and ice. The hard surface could have formed due to reactions with solar radiation and compaction, but regardless of the cause it challenges the assumption that cometary material is essentially unchanged since the formation of the solar system. The presence of complex polymers in the surface material is also likely a recent phenomenon. Philae's cameras revealed a wide range of hard-to-explain surface features. Radio signals used to probe the comet show that the interior has a relatively consistent composition and is much more porous than expected based on the nature of the surface.

July 30, 2015 1:15 PM

### Battery proliferation makes lithium a hot commodity

Christian Science Monitor: A lithium boom is expected in the coming decades as new applications for the so-called wonder material continue to multiply. A good conductor of heat and electricity, lithium is also extremely light. Over the past decade, it has been used extensively in smart phones, tablets, and laptops. But with the advent of electric vehicles, the demand for lithium will probably increase significantly. For example, the new Tesla Motors lithium-ion battery gigafactory, currently under construction in Nevada, will require some 15 000 tons of lithium carbonate a year. Although not a rare commodity, lithium comes mainly from three regions around the world: Nevada, the Atacama Desert in South America, and China. Whether supply will be able to keep up with demand remains to be seen.
July 30, 2015 1:04 PM

Science: The Fair Access to Science and Technology Research Act (FASTR) requires federal agencies that spend more than $100 million on research to make freely available any peer-reviewed papers from the research within 12 months of publication. On Wednesday, the Senate Committee on Homeland Security and Governmental Affairs approved the proposal, and next it will go to the full Senate for approval. The original proposal for FASTR set the deadline for open access at 6 months, but it was pushed back due to opposition from scientific societies and university and research groups. The 12-month timeline is consistent with the current National Institutes of Health standards. July 30, 2015 12:05 PM ### Desert aquifers may serve as huge carbon sinks New Scientist: A saline aquifer underneath a desert in northwest China has been found to contain surprisingly large amounts of carbon, according to Yan Li of the Chinese Academy of Sciences in Urumqi and colleagues. From water samples taken from the Tarim basin and from nearby rivers and other water sources that feed into it, the researchers have been able to create a timeline of how much and when carbon entered the closed drainage system. They found that the amount of carbon has increased dramatically because of human agricultural practices, which call for overirrigation of crops in desert areas to leach away the salt. The salt washed out of the soil makes its way into the aquifer, and the increasingly salty water is able to absorb and store more carbon than pure water. How much irrigating of deserts occurs around the world is unknown, but if the Tarim basin is any indication, the potential of similar aquifers to serve as carbon sinks could become increasingly important with the onset of global warming. July 30, 2015 11:50 AM ### Obama establishes supercomputing initiative Verge: On Wednesday, President Obama signed an executive order creating the National Strategic Computing Initiative (NSCI). The overall goal of the initiative will be to coordinate the US's efforts in high-power computing across a range of fields including medicine, nuclear research, weather forecasting, and aerospace. The most specific goal involves building an exascale computer by 2025. Such a computer would be 100 times as powerful as the two most advanced computers currently under development in the US—Summit and Sierra—which will both reach 100 petaflops when they are completed in 2017. Reaching the exascale level will require either massive amounts of power to supply the computer with energy or significant architecture breakthroughs to allow more efficient energy use. July 29, 2015 4:26 PM ### SpaceShipTwo crashed because feathering system was released early Verge: After Virgin Galactic's VSS Enterprise, an experimental SpaceShipTwo design, broke apart in flight last year, the National Transportation Safety Board (NTSB) found that the failure was due to the craft's wings, which had shifted position. Now the agency has confirmed that the problem was caused by human error. In normal operations, the wings are moved into a "feathering" position as the craft reaches apogee in order to slow it down for reentry into Earth's atmosphere. The NTSB's investigation revealed, however, that the copilot unlocked the wings while the craft was still climbing and before it went supersonic. As the craft passed Mach 1, the force on the unlocked wings pushed them into feathering position. Because the craft was not in the proper orientation for the feathering maneuver, the resulting forces on the craft caused it to break up. Virgin Galactic said that it has now added an inhibitor that prevents the wings from being unlocked before the craft has reached Mach 1.4. July 29, 2015 3:40 PM ### UK report provides guidelines for dealing with solar storms Guardian: Any day now Earth could experience a large-scale coronal mass ejection from the Sun that could cause far-reaching problems ranging from power outages to communications disruptions. Now the UK’s Department for Business Innovation and Skills has issued a report, Space Weather Preparedness Strategy, which spells out the potential dangers of such weather events and the steps the government should take to mitigate their effects. Among other things, the report proposes increasing the resilience of the nation’s infrastructure, establishing a system of warnings and alerts, and planning effective emergency response measures. Based on the Carrington event of 1859, people could have as little as 12 hours' advance warning of any similar impending severe solar weather event. July 29, 2015 1:35 PM ### Teleportation at the quantum level NPR: Teleportation may one day be possible, but rather than transferring matter from one point to another, it most likely will involve transferring information, according to Chris Monroe and David Hucul of the University of Maryland’s Joint Quantum Institute. Because any carbon atom is identical to any other carbon atom, the actual atoms that make up an object don’t need to be moved. Rather, the object could theoretically be rebuilt from the atoms at hand, if the states of all the atoms of the original object were known. To that end, the researchers have been working with a laboratory full of lasers, mirrors, and lenses to measure an atom’s information and transpose it to another. Although such a system of quantum teleportation would never work for moving people, they say, it could have its uses, such as in quantum computing. July 29, 2015 1:25 PM ### Arecibo Observatory faces conflict between private and public funding Scientific American: With the recent launch of Breakthrough Listen—the privately funded, large-scale search for extraterrestrial intelligence, or SETI—the governing committee of the Arecibo Observatory in Puerto Rico has been confronted with a problem: If the committee decides to partner with Breakthrough Listen and accept funding from Yuri Milner’s$100 million initiative, Arecibo, the world’s largest and most sensitive single-dish radio telescope, could risk losing its financial support from NSF, the US federal agency that owns it. Budget cuts have forced NSF to start divesting from older facilities in order to fund newer ones. Although funding from Breakthrough Listen would help to keep the facility running, it would not cover all the expenses, such as Arecibo’s basic operational costs. Whether NSF will continue to contribute to Arecibo's maintenance, however, depends on the details of the proposed partnership, which have yet to be provided to NSF by Arecibo’s management, and on how such a partnership would affect NSF’s broader mission regarding use of the telescope.

July 28, 2015 3:42 PM

### Novel technique used to produce single-molecule transistor

IEE Spectrum:  A transistor consists of two electrodes, a source and a sink, and a gate that controls the flow of current between them. Recently researchers created a single-molecule transistor, and now a new and improved technique uses charged atoms for the gate. In this new transistor, a phthalocyanine molecule functions as the transmission channel, which rests on an indium arsenide substrate. Using a scanning tunneling microscope (STM), the researchers arranged indium ions around the H2Pc channel. The transistor turns "on" when enough indium ions are collected around the channel to create sufficient charge to alter the energy of the H2Pc molecule's electrons. When that happens, electrons from the STM, now being used as the transistor's source, can pass through the channel into the substrate.

July 28, 2015 3:19 PM

### Japan plans to restart nuclear reactors soon

World Nuclear News: After the Fukushima Daiichi Nuclear Power Plant was severely damaged by a tsunami and earthquake in 2011, Japan closed all of its nuclear power plants. The following year, the country established the Nuclear Regulation Authority (NRA), which drew up new standards for nuclear power plant operation. Now, after a series of upgrades and inspections at the Sendai Nuclear Power Plant, Kyushu Electric Power Company plans to ask the NRA to perform a final inspection of the Sendai 1 reactor. If no problems are found during the week-long process, which is expected to begin on 3 August, the reactor could start operations as soon as 10 August. It would be the first nuclear reactor to restart in Japan since 2011, and 20 more reactors are in line to follow. The government hopes that nuclear power will produce up to 22% of the country's electricity by 2030 and decrease its reliance on fossil fuel imports.

July 28, 2015 12:50 PM

### Hillary Clinton comes out strong on green energy

New York Times: Climate change may be one of the major issues in the 2016 presidential campaign. According to a recent poll by the New York Times, two-thirds of Americans favor political candidates who propose to take action on global warming. One presidential hopeful to take up the challenge is Hillary Clinton, who on Monday announced an ambitious goal to produce 33% of the US’s electricity from renewable sources by 2027. She has called for the installation of a half-billion solar panels by 2020 and for the generation of enough carbon-free energy to power every US home within a decade. Despite her strong support for green energy, however, some environmentalists say she must also develop a strong stance against fossil-fuel projects, such as the Keystone XL pipeline, on which she has so far refused to express an opinion, citing her role in evaluating the project when she was secretary of state.
July 28, 2015 11:35 AM

### Turning cells into tiny lasers for medical diagnostics

Nature: Biological cells have been turned into microlasers by injecting them with droplets of oil or fat mixed with a fluorescent dye. The droplets, which act as the gain medium, can then be activated by short pulses of light. Matjaž Humar and Seok Hyun Yun of Harvard Medical School are developing the technique to be used in the diagnosis and treatment of tumors and other medical conditions. Although luminescent probes have already been used with much success, the intracellular microlasers have a narrower emission spectrum, which allows for the tracking of thousands of cells simultaneously. The researchers have even experimented with using fluorescent polystyrene beads of different diameters to tag individual cells.
July 27, 2015 2:13 PM

### Massive black hole found during study of archival data

Scientific Computing: A black hole 100 million solar masses in size has been spotted in the process of devouring a star. While examining spectra of objects taken by the Sloan Digital Sky Survey, Andrea Merloni of the Max Planck Institute for Extraterrestrial Physics in Garching, Germany, and his colleagues found an unusual change between 1998 and 2005 in the spectrum of one galaxy located some 3.5 billion light-years away. Further confirmation of the high-energy emission came when the team discovered that both the European Space Agency's XMM-Newton and NASA's Chandra X-Ray Observatory, which had taken pictures of the region at about the same time, had also seen the massive flare. An analysis of the data from the three archival sources confirmed that the flare fit the model of a star being pulled into a massive black hole.

July 27, 2015 1:03 PM

### First data from new LHC run are presented in Vienna

Guardian: Researchers from CERN's Large Hadron Collider (LHC) are presenting their latest results at the European Physical Society's Conference on High Energy Physics in Vienna. The ATLAS team confirmed an unexpected finding from the CMS team during the previous LHC run—that regardless of the incident collision angle of the particles, there is an increased probability they are being emitted at a similar azimuthal angle. That behavior is expected in heavy particle collisions but not in proton–proton collisions. From the new run, ATLAS also released the first measurement of the jets of hadrons produced from the collision of quarks and gluons. The measurement, which is in line with the measurements taken during the previous run, reveals that the higher collision energy is producing noticeably more frequent jets.

July 27, 2015 11:45 AM

### Brain revealed through photoacoustic imaging

NPR: A new technique that combines “the speed and precision of light with the penetrating ability of sound” has been used to create high-speed, detailed three-dimensional images of a living mouse brain, writes Jon Hamilton for NPR. Developed by Lihong Wang of Washington University in St Louis, photoacoustic imaging uses a laser to send light pulses through the mouse’s skull and into its brain, where they bounce around and cause the molecules to vibrate. The vibrations emit distinctive sound waves, which can be used to monitor brain activity and study individual brain cells. The technique could one day be applied to other areas of the body to look for anomalies such as tumors in the breast, skin, and even individual blood cells.
July 27, 2015 11:40 AM

### "Bubble" greenhouse proposed for remote, arid regions

SciDev.Net: A sealed greenhouse that uses evaporation and condensation to desalinate saltwater for irrigation is being developed by researchers in Australia. In the design the evaporation equipment is located outside the greenhouse structure. Air is bubbled through water-filled columns to increase the air–water interface and encourage evaporation. Although the novel humidification–dehumidification process requires more energy than other desalination methods, such as solar-powered reverse osmosis, its simplicity and small scale could make it useful in isolated areas where local people with little training could set it up and run it. In addition, such a sealed structure would provide a cool, humid environment, which promotes plant growth, and would protect crops from insects and disease.
July 24, 2015 12:10 PM

### Mammoth DNA suggests climate change was primary driver in extinction

Science: Mammoths and many other large mammals suffered a massive population decline between 30 000 and 20 000 years ago that eventually led to their extinction. Human expansion, and the hunting associated with it, is widely considered to be a major factor in that decline, but a new study of DNA collected from mammoth fossils suggests that the populations were shrinking well before human expansion was significant. Alan Cooper of the University of Adelaide in Australia and his colleagues established a connection between the diversity of DNA found at specific sites and the size of the species population. Creating a timeline of temperature changes from sediment cores, they found that drops in DNA diversity, and therefore overall population size, were tied to periods of significant short-term warming.

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