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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 72 posts for the selected month (August 2015).
August 27, 2015 3:20 PM

US program promotes concentrated solar power

MIT Technology Review: Eleven new solar projects are to receive $24 million in funding as part of a new program launched by the US Advanced Research Projects Agency–Energy. Called MOSAIC (microscale optimized solar-cell arrays with integrated concentration), it aims to promote concentrated photovoltaic technologies in order to achieve a higher solar-to-electricity conversion rate. However, because of the materials required, such systems have proven to be very expensive, and they only work in regions with a lot of direct sunlight, such as the American Southwest. The new program seeks to develop more affordable materials and improve the technology to make use of more diffuse sunlight. The goal is to reduce US greenhouse gas emissions and its dependence on foreign sources of energy.
August 27, 2015 2:00 PM

Next-generation synchrotron fires up in Sweden

Nature: A new synchrotron x-ray light source built at Sweden’s MAX IV facility in Lund achieved its first milestone event on 25 August when electron bunches were successfully beamed all the way around the synchrotron’s 528-m-long outer ring. The electrons, whose circular trajectories cause them to emit x rays, are steered and focused by a series of magnets. Compared with earlier models, the new machine achieves stronger magnetic fields with the use of more compact magnets, which are also less expensive and use less electricity. The resulting intense pulses of x rays could be used in any number of laboratory applications, such as studying the chemical reactions inside a battery in real time or the structure of much smaller protein crystals than has been possible with existing light sources.
August 27, 2015 1:00 PM

Emission-reduction effort in London fails to improve air quality

New Scientist: Despite the establishment of a low-emission zone in London in 2008 to try to cut the city’s traffic-related air pollution, no measurable improvement in air quality was achieved during the first three years of the program, according to a study by Frank Kelly of King’s College London and his colleagues. The researchers based their finding on measurements of air particulates and polluting gases, such as nitrogen oxide, and on the respiratory health of schoolchildren. They found neither measurable decreases in NOx or particulate matter nor marked improvement of various pollution-related symptoms, such as wheezing, rhinitis, and eczema, in children at 23 London schools. The researchers say one reason might be an increase in the number of diesel-powered vehicles, which have been promoted as producing fewer greenhouse gases but which may also generate more health-compromising pollutants.
August 27, 2015 11:40 AM

Parents sue school over son’s alleged sensitivity to its Wi-Fi network

Ars Technica: Parents of a young boy have brought a lawsuit against the private boarding school he attends. They claim that their son is suffering from electromagnetic hypersensitivity syndrome due to the industrial-capacity Wi-Fi system the school installed and that the electromagnetic emissions cause him to experience “headaches, nose bleeds, dizziness, chest pains and nausea,” all of which disappear once he is home. The parents allege that when they brought their concerns to school officials and asked that the school “make reasonable accommodations” for their son’s “disability” by reducing the emissions to a physically tolerable level, the school refused, adopted a hostile attitude, and threatened to dismiss the student. Although a number of people say they suffer from electromagnetic hypersensitivity, no scientific evidence or study backs up that claim.
August 26, 2015 4:40 PM

Quantum dots could turn windows into solar panels

Ars Technica: Although solar panels can generate a large amount of carbon-free electricity, installing them in existing buildings is expensive. Incorporating them into windows and other parts of buildings would make solar energy much more affordable. However, photovoltaic cells not only block the view but also absorb a certain amount of the incoming light and cause the light that does enter the building to be tinted. A new alternative uses a transparent polymer that can be embedded in the window or applied as a coating. The polymer includes a diffuse cloud of quantum dots made of copper, indium, and selenium. The dots absorb light across the spectrum and reemit it at a specific IR wavelength, which the polymer then guides to the edge of the window glass. From there, the light is fed into a silicon photovoltaic device, which very efficiently absorbs it. Filtering out only 20% of the incoming sunlight, the device can convert just over 3% of it to electricity. Although the new material cannot harvest as much sunlight as regular solar panels, the giant walls of glass on a skyscraper could still produce a fair amount of electricity for relatively low cost.
August 26, 2015 3:10 PM

Articles with shorter titles receive more citations, says study

Nature: Journals that "publish papers with shorter titles receive more citations per paper," according to a study published in Royal Society Open Science. Adrian Letchford of the University of Warwick in Coventry, UK, and his colleagues mined the Scopus database and analyzed 140 000 papers listed there that were published between 2007 and 2013. They reached their conclusion by comparing title lengths and numbers of citations. However intriguing their finding, the researchers say, it is not necessarily definitive because of the number of other factors that could be involved, including the fact that different journals place different restrictions on the number of characters allowed in a title and the fact that subject matter and author seniority can also affect a paper’s citation rate. Regardless, clear, tightly constructed titles are always in the authors' best interests, says Karl Ziemelis, Nature’s chief physical sciences editor.
August 26, 2015 3:00 PM

Supposed dragon pictograph refuted by x-ray technology

Science: Since the late 1920s, when a rock painting was discovered in Utah’s Black Dragon Canyon, people have been debating what exactly is depicted in the faded and ancient pictograph. Over the years it has variously been described as a winged monster, a dragon, or a pterodactyl. Rock art researchers and archaeologists, however, have said that rather than showing a single figure, the drawing depicts five figures—two humans and three animals. Such a tableau, they say, is common in the Barrier Canyon style of art seen in that region. To try to finally lay the controversy to rest, researchers used x-ray fluorescence to measure the iron content of the red ochre pigment used in the drawing and a software program called DStretch, which can boost and sharpen digital images. The two methods revealed “pretty clearly” that there are five figures, says Marvin Rowe, a retired professor emeritus at Texas A&M University in College Station and a coauthor of the study.
August 26, 2015 11:40 AM

Stephen Hawking proposes that information may not be lost in black holes

Wall Street Journal: One of the apparent consequences of Stephen Hawking's theory that black holes leak radiation is that over time they would evaporate and disappear. The information about all the particles they absorbed would then be lost. That concept, however, contradicts a tenet of quantum mechanics that information cannot be lost or destroyed. On Tuesday, at a conference at the Royal Institute of Technology in Stockholm, Sweden, Hawking presented a new theory about how that information might be preserved: Instead of being stored in the interior of a black hole, the information may be stored in its boundary, the event horizon, and then carried away by the emitted radiation.

August 25, 2015 2:35 PM

Saturn’s F ring may have formed from collision of two moons

Japan Times: Encircling Saturn’s main ring system is a narrow band of icy particles called the F ring. But until now, how the ring originated and why it appears to have two tiny “shepherd” moons—Prometheus and Pandora—was not known. Ryuki Hyodo and Keiji Ohtsuki of Japan's Kobe University have used computer simulations to show that the ring may have resulted from the collision of two small satellites near the outer edge of Saturn’s main ring. However, the satellites probably did not collide head on, but rather at an angle. According to the researchers, “Such an impact results in only partial disruption,” not total destruction, of the moons. The narrow ring of particles produced would then go on to form a new ring. Not only may that theory explain Saturn’s F ring, but it could also explain certain features in the Uranian system, says CNRS's Aurelien Crida, who commented on the study in Nature Geoscience.
August 25, 2015 2:20 PM

D-Wave quantum computer appears to run faster than classical model

New Scientist: Canada’s D-Wave Systems, which sells what purport to be the world’s first quantum computers, says its latest model is 15 times faster than a regular PC. However, that claim has been disputed by various experts. One issue is the nature of the test. The D-Wave computer was tasked with solving a random optimization problem, which it was able to do in 20 microseconds. The regular computers took longer to find a solution “of equivalent quality.” But although the D-Wave computer found more solutions faster than the regular computers, it may not necessarily be faster at coming up with the best solution. Another issue is that classical computers use multiple cores to split up the computations and speed up the processing time. But the test PC used just a single core. Perhaps the best way to prove D-Wave’s computers are truly quantum is to have them show progressively faster performance on ever-larger problems, which hasn't happened yet.
August 25, 2015 2:15 PM

Loophole exploited in carbon-credit facilities

Nature: Although carbon credits were created as part of the Kyoto Protocol to encourage nations to invest in emissions-reduction projects, they can become so valuable that in some cases they have presented a perverse incentive. For certain waste gases, revenues from carbon credits can exceed the abatement costs and even the costs of producing the main product, according to a recent study published in Nature Climate Change. Such was the case for at least two Russian chemical plants, which since 2008, when the credit scheme began, were found to have increased their production of two potent greenhouse gases—trifluoromethane and sulfur hexafluoride—with no corresponding increase in their production of chlorodifluoromethane, a chemical used as a refrigerant. They then collected the financial benefits from destroying the greenhouse gases that they had produced. Such abuses exist, say the study authors, because of the lack of oversight by participating governments. The program may be improved or even abandoned altogether as new climate targets are set at the upcoming United Nations climate change conference to be held in Paris later this year.
August 25, 2015 1:46 PM

Middle Eastern conflicts have lowered air pollution

Los Angeles Times: Satellite images of the Middle East over the past 10 years have revealed a drop in the levels of nitrogen oxide, sulfur dioxide, and other air pollutants. The drop does not appear to be the result of any clean-air laws or other changes but does coincide with the spreading conflicts there. Jos Lelieveld of the Max Planck Institute for Chemistry in Mainz, Germany, and his colleagues found the trend in data collected by the Ozone Monitoring Instrument on NASA's Aura spacecraft. They were studying the impact of air-quality standards adopted by countries in the region. Since 2011, when the Arab Spring protests reached Syria and escalated into civil war, the concentration of NO has dropped by 40% over Damascus and by 50% over Aleppo. Similar drops in emissions were noted in Iraq and Egypt. However, emissions rose in Beirut and other parts of Lebanon, probably because of the flood of refugees to those countries.

August 24, 2015 3:20 PM

Nanotube medical sensors appear safe and functional in lab animals

Nature: Carbon nanotubes wrapped in polymers can be used to test for the presence of a range of molecules in blood. The polymers are designed to attach to specific molecules. The nanotubes fluoresce naturally, but their brightness changes when they are attached to the target substance. This makes it easy to detect the presence of the substance as well as its concentration. Michael Strano of MIT and his colleagues have successfully tested the devices as both injections and subdermal implants in mice. The injectable devices can be used for detecting large molecules such as fibrinogen, which is involved in blood clotting, a process that is not easy to monitor with existing technologies. An implant for detecting nitric oxide, which was embedded in a hydrogel matrix, was functional in mice for more than a year with no local inflammation.

August 24, 2015 1:00 PM

Greenland glacier loses largest ice chunk so far

BBC: An ice sheet the size of Manhattan broke off Greenland’s Jakobshavn glacier between 13 August and 19 August. Based on satellite observations, the 12.4-km2 chunk may be the largest ever observed to break off from that glacier. Because of rising air and sea temperatures in the Arctic, such calving events have been occurring more often over the past several decades. In fact, the Greenland ice sheet appears to be losing much more ice than Antarctica and is a significant contributor to sea-level rise, adding about a millimeter per year.
August 24, 2015 11:43 AM

New material increases capabilities of supercapacitors

Science: The storage capacity of a supercapacitor is limited by the surface area of the electrodes and by the electrodes' ability to absorb and release electrons. Research on redox-active materials focuses on the latter problem, but the materials are fragile and not particularly porous so have a low surface area. Two years ago, William Dichtel of Cornell University and his colleagues created a highly porous crystal, called a covalent organic framework (COF), that is also redox-active, but it did not have the conductivity necessary to be commercializable. Now they have revealed that coating their COF with a conductive polymer increased the capacitance from 160 F/g to 350 F/g, higher than any commercial supercapacitor. Because the materials used in Dichtel's device are readily available, they have much more promise for commercial use than harder-to-create carbon-nanotube capacitors.

August 21, 2015 2:30 PM

Fisheries management moves toward broader, ecosystem-based approach

Nature: Because of global warming, fisheries managers may be forced to change the way they determine yearly catch limits and take a broader approach that includes a better understanding of ecological processes. Traditionally, managers set catch limits based on the populations of individual species and assumptions about population trends. However, an unusually warm water mass in the northern Pacific Ocean over the past 18 months has prevented forage species such as anchovies, sardines, and krill from migrating to coastal waters, where they are a major food source for salmon, tuna, and whales. Moreover, those forage species are already at historic low numbers, and a possible El Niño later this year could further disrupt the food chain. New tools, such as the California Current Predator Diet Database, are providing a more comprehensive, ecosystem-based approach through consideration of such variables as predator–prey relationships, climate, and economic factors.
August 21, 2015 12:00 PM

July was hottest month on record

Los Angeles Times: The average global temperature for the month of July was 16.61 °C, the highest monthly global temperature since record-keeping began in 1880. That information comes from a recent report by the National Oceanic and Atmospheric Administration. Record-high temperatures were observed in many regions, including eastern Africa, northern South America, parts of southern Europe and central Asia, and the western US. Moreover, the first seven months of the year were also the hottest January-to-July period since 1880. The findings support NOAA’s prediction of an El Niño event occurring later this year.
August 21, 2015 11:14 AM

Metamaterial hides magnetic field from outside detection

New Scientist: Alvaro Sanchez of the Autonomous University of Barcelona, Spain, and his colleagues have built a device that makes a magnetic field seem to disappear as it enters on one side and then reappears on the other. The device uses spherical layers of superconducting and magnetic materials to shield the magnetic field from incoming electromagnetic fields. The configuration allows the magnetic field to traverse the diameter of the sphere through a tube designed to minimize any loss of strength. When the magnetic field exits the tube, it looks like a monopole, a magnetic field that doesn't form a loop with itself.

August 20, 2015 2:32 PM

Enormous galaxy cluster appears to defy cosmological principle

Washington Post: The cosmological principle is the idea that at large enough scales there shouldn't be any definable structures to the material present in the universe. A collection of galaxies 7 billion light-years away is just the most recent structure that appears to violate that principle. The collection, which appears to be shaped as a ring 5.6 billion light-years across, was identified from observations of nine gamma-ray bursts. The similarities of the bursts and their nearness suggests that they originated from a single intergalactic feature. Lajos Balazs of the Konkoly Observatory in Budapest, Hungary, and his colleagues say that there is a less than 1 in 20 000 chance that the arrangement is random. Researchers had previously spotted a cluster nearly 10 billion light-years across, but the evidence for that structure isn't as strong. However, the generally accepted upper limit for the size of gravitationally bound structures is 1.2 billion light-years.

August 20, 2015 2:30 PM

China emitting less carbon than previously thought

Science: According to a new study released yesterday, China is emitting 13% less carbon since 2000 than was previously estimated. The main reason for the difference is that China's coal supply was assumed to be of similar quality to coal burned in Western nations. China’s coal, though, is actually of lower quality and therefore has a lower carbon content than that burned in the US and Europe. Despite the lower estimate, China remains the largest carbon emitter in the world. And because it is burning low-quality coal, it must burn more to produce the required heat, which releases more particulates and other pollutants into the air. Nevertheless, China’s pledge last year to cut emissions by 2030 has been seen as a good sign by other nations, and the current study should help its government set policy to achieve that goal.
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