Science

Dark-matter distribution is smoother than previously thought Smooth and diffuse: the latest map of dark matter The distribution of dark matter in the universe appears to be smoother and more diffuse than previously thought – according to a study of wide-area images of the distant universe. Astronomers at the University of Edinburgh in the UK, Leiden University in the Netherlands, the Argelander Institute for Astronomy in Germany and the Swinburne University of Technology in Australia used the weak gravitational lensing of light from far-off galaxies to map the distribution of dark matter in intervening parts of the universe. The map is at odds with a prediction of dark-matter distribution that is based on the structure of the early universe based on measurements of the cosmic microwave background made by the Planck satellite. “Our findings will help to refine our theoretical model for how the universe has grown since its inception, improving our understanding of the …

Scientists have discovered a dangerous and highly transmissible form of multidrug-resistant bacteria lurking on a Midwestern hog farm, according to a study published yesterday. The bacteria have easily shared bits of DNA that help them fight off antibiotics called carbapenems, and this is the first time such microbes have been found on a U.S. farm. When these bacteria infect humans, they are extremely difficult to treat, and are often deadly. The discovery also poses something of a mystery. Carbapenems are not used on farms—they are mostly used in hospitals—so it is perplexing that microbes developed abilities to withstand a drug they probably did not encounter. The feat illustrates the ease with which antibiotic resistance traits travel to new locations and jump into different species, but it is still unclear what the findings mean for public health. As yet there is “no evidence that it is entering the food supply,” says Thomas Wittum, a scientist at …

The EPA has started flexing its newfound powers to control chemicals in the U.S. Last week the agency announced the first 10 compounds it will evaluate for safety under the reformed Toxic Substances Control Act (TSCA). The legislation, amended last June, strengthens the agency’s authority to regulate new and existing chemicals. Its list, which includes substances such as asbestos, is just the beginning of its revamped efforts. In the coming years, the U.S. Environmental Protection Agency plans to review thousands of chemicals for their potential risk to human health and ecosystems. It could restrict or ban any of them—something the EPA has had little power to do before. “These 10 chemicals are not new, they’ve been in use for decades,” explains Richard Denison, a lead senior scientist at the Environmental Defense Fund. “But under the old law, there was no mandate for EPA to review those chemicals—that’s part of why this reform was so important.” …

Nanoporous network: structural colour inspired by a tropical bird A new way of producing structural colours – inspired by the nanoporous feathers of a brightly coloured South American bird – has been developed by researchers in the US, Switzerland and Saudi Arabia. The technique relies on a self-assembling, random network of sub-wavelength pores in a metallic alloy to produce a wide-range of colours. According to the researchers, their technique is more robust and easier to scale up for commercial fabrication, and could be used in a range of applications including lightweight coatings for cars and aircraft. Animals use colours for a range of functions, from courtship displays to camouflage. While many of these colours are produced by pigments, others are produced by surface structures that interact with light and reflect specific wavelengths. Researchers have long been interested in such structural colouration because of its durability and many potential applications. “Pigments fade away over relatively short …

Vibrots tumble and turn Twisted motion: vibrot converts vertical motion to rotation Vibrots are tiny devices that convert linear vibrations into rotational motion and are of great interest to scientists studying the collective motions of particles in physics, biology and chemistry. In this latest study, Christian Scholz, Sean D’Silva and Thorsten Pöschel of Friedrich-Alexander-Universität Erlangen-Nürnberg in Germany have created a vibrot that is powered by a vibrating floor – something that is common in the processing of granular materials, where collective motion can emerge. The cylindrical device is about 1 cm in diameter and is supported by seven legs, which are all bent at the same angle (see figure). The legs are springy and this causes the vibrot to rotate when subjected to vertical vibrations. In this latest work, Scholz and colleagues identified two distinct ways in which this motion occurs: “ratcheting” and “tumbling”. The ratcheting mode occurs at relatively low amplitudes of vibration. The legs …

On the campaign trail, education often took a backseat to issues like trade and immigration for Donald Trump. He offered few concrete details about his plans, which were often vague and even at odds with what any president has the power to do. Yet the tone of his campaign—and his rhetoric on issues ranging from minorities to climate change—has many educators and academics worried about the future of liberal arts and STEM (science, technology, engineering and math) education. “Donald Trump has shown a contempt for science, a willingness to play fast and loose with the very idea of truth and an absence of intellectual curiosity,” says Laurence Tribe, professor of constitutional law at Harvard Law School. “This leaves me with the sinking feeling that he will have a terribly destructive impact on the entire project of making excellent education broadly available.” The President-elect’s clearest stance may be his support of school choice, the view that …

One at a time: the single-electron pump Physicists should finally be able to rid themselves of the cumbersome and inaccurate definition of the ampere. That is the claim of metrologists in Germany, who have measured electrical current by counting single electrons travelling along a microscopic wire. The researchers say that their technique will allow scientists in a number of different disciplines to make better measurements of tiny currents. The move to revamp the ampere is part of a more general overhaul of the SI system of units. It is envisaged that all seven base units – the ampere, second, metre, kilogram, kelvin, mole and candela – will be anchored to unvarying constants of nature. In particular, scientists are eager to redefine the kilogram, which is currently based on the mass of a specific lump of platinum-iridium sitting in a Paris safe and slowly shedding atoms. It is partly to sever its link with the kilogram …

President-elect Donald Trump says he loves NASA and that “space is terrific,” although “we’ve got to fix our potholes,” too. These statements—given to a 10-year-old boy who asked about NASA at an event in Manchester, New Hampshire in November 2015—would prove to be the most informative things Trump offered about the nation’s space program for most of his presidential campaign. Almost a year later, as he campaigned along Florida’s “Space Coast” near NASA’s Kennedy Space Center, Trump offered more specifics about his space-policy plans, vowing to revitalize the agency through cost-saving partnerships with the burgeoning commercial space industry. According to an accompanying op-ed from the campaign, NASA under Trump would transform from “a logistics agency for low-Earth orbit activity” into a spaceflight powerhouse with the lofty goal of conducting “human exploration of our entire solar system by the end of this century.” As of yet, Trump has made no further mention of space in his public statements …

On Thursday the United States House Committee on Science, Space and Technology, run by Texas Republican Lamar Smith, retweeted a Breitbart News story that dismissed climate change as “a scare” manufactured by “alarmists”. An overwhelming majority of climate scientists agree that the phenomenon is real and primarily the result of human activities, and many of them took to social media to express their dismay (to put it mildly) that the committee, which oversees government offices such as the Environmental Protection Agency and the National Oceanic and Atmospheric Admiration, would promote such a misguided article. Here are a few of the best reactions: I wrote a brief, public rant on Facebook about that @HouseScience tweet. h/t @hormiga @PeterGleick https://t.co/seUTKycogb pic.twitter.com/Y0PaU7TRhZ — Karen James (@kejames) December 1, 2016 A classic example of false news. https://t.co/ECOkzeBW9j The truth? pic.twitter.com/zEZGzOF7vi — Katharine Hayhoe (@KHayhoe) December 1, 2016 This is fake news, bad science, and basically, crap, from the House …

Earthquake-aftershock puzzle solved, say physicists Noise threshold: are aftershocks a part of the main earthquake event? The idea that smaller earthquakes (aftershocks) follow major earthquakes is a well-established concept in geophysics. However, aftershocks are not explained by the avalanche model that is used to describe earthquakes and similar phenomena such as the cracking of solid materials. The model dictates that events such as earthquakes are random and therefore there should be no correlation between successive earthquakes. Now, Sanja Janićević, Lasse Laurson and colleagues at Aalto University in Finland have shown that this discrepancy could simply be a result of how aftershocks are measured. Writing in Physical Review Letters, the physicists describe experiments in which they monitored the cracking of a solid material. They found that when they set the detection threshold of their apparatus at high values – to avoid measuring noise – an individual avalanche event appeared as a sequence of seemingly unrelated events. …

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