Welcome to the Saturday Science Edition of Overnight News Digest
Overnight News Digest is a regular daily feature which provides noteworthy news items and commentary from around the world. The editorial staff includes side pocket, maggiejean, wader, Doctor RJ, rfall, and JML9999.
Neon Vincent is our editor-in-chief.
Special thanks go to Magnifico for starting this venerable series.
Astronomy
The Inner Workings Of Red Giant Stars
Sunspot, filaments, plages, and flares — visible signs of the Sun’s magnetic field riddle its atmosphere. But divining magnetic activity inside the Sun is another matter entirely. We can’t directly see the magnetic fields within stars, and that makes it difficult to connect a star’s visible tortured gas with the inner workings of its magnetic field. Everything from predicting the strength of the next solar cycle to describing stellar aging hinges on better understanding these fields. [...] But the fluctuations seen in these few dozen red giants are weaker than those in hundreds of other red giant stars that Kepler observed during the same time period. To explain this weird behavior, Fuller and colleagues propose that a super-strong inner magnetic field is weakening the brightness variations. For that to be true, a field of at least 100,000 Gauss (10 Teslas) must be lurking in these stars’ cores — that’s 100,000 times stronger than the Sun’s polar magnetic field, and 30 times greater even than sunspots, the strongest magnetic concentrations found on the Sun. To understand how they came to this conclusion, let’s take a Magic School Bus–style ride into the innards of a red giant star. A large convective envelope of boiling gas surrounds a radiative core where fusion happens. Sound waves roil the outer envelope, interacting with ocean wave–like motions called gravity waves within the star’s hot, dense plasma core. These waves are not to be confused with gravitational waves, which are ripples in the fabric of spacetime (note to astronomers: one of these terms really ought to get a new name!). Sound waves can “talk” to gravity waves, donating energy to the core. But in the presence of a strong magnetic field, the gravity waves can’t talk back — they’re trapped in the core. So the sound waves’ energy leaks away into the gravity waves, and those gradually dissipate away. The lost energy has little effect on the giant star other than the slight weakening of the hemisphere brightness variations, but it’s in this subtle signal that astronomers deduce the incredible strength of the magnetic field. skyandtelescope.com
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Search for Life: Where Should A Europa Lander Touch Down?
If humanity ever launches a life-hunting mission to the icy surface of Europa, the probe should probably touch down on the "chaos terrain" of the ocean-harboring Jupiter moon, a new study suggests. Europa's complex chaos regions — which feature numerous cracks, ridges and other signs of geological activity — may offer a way to sample the moon's huge subsurface ocean of liquid water, which is buried beneath an estimated 60 miles (100 kilometers) of ice, researchers said. "If you had to suggest an area on Europa where ocean water had recently melted through and dumped its chemicals on the surface, this would be it," study co-author Mike Brown, an astronomer at the California Institute of Technology (Caltech), said in a statement. [...] The researchers don't know what the chaos-region chemicals are, but they think the compounds could provide a window into Europa's possibly life-supporting ocean. "We think we might be looking at salts left over after a large amount of ocean water flowed out onto the surface and then evaporated away," Brown said. "They may be like the large salt flats in the desert regions of the world, in which the chemical composition of the salt reflects whatever materials were dissolved in the water before it evaporated." space.com
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Biology
Singing Calms Baby Longer Than Talking
In a new study from the University of Montreal, infants remained calm twice as long when listening to a song, which they didn't even know, as they did when listening to speech. "Many studies have looked at how singing and speech affect infants' attention, but we wanted to know how they affect a baby's emotional self-control," explained Professor Isabelle Peretz, of the university's Center for Research on Brain, Music and Language. "Emotional self-control is obviously not developed in infants, and we believe singing helps babies and children develop this capacity." The study, recently published in Infancy, involved thirty healthy infants aged between six and nine months. Humans are in fact naturally enraptured by music. In adults and older children, this "entrainment" is displayed by behaviours such as foot-tapping, head-nodding, or drumming. "Infants do not synchronize their external behaviour with the music, either because they lack the requisite physical or mental ability," Peretz explained. "Part of our study was to determine if they have the mental ability. Our finding shows that the babies did get carried away by the music, which suggests they do have the mental capacity to be "entrained"." The researchers took a variety of measures to ensure the children's reaction to the music was not influenced by other factors, such as sensitivity to their mother's voice. Firstly, both the speech ("baby talk" and adult-directed) and the music presented to infants were produced in Turkish, so that the song and language were unfamiliar. "The performer sang Turkish play songs, not Western ones. This is an important point as studies have shown that the songs we sing to infants have a specific range of tones and rhythms," explained first author Mariève Corbeil, also of the University of Montreal. "Every parent knows it's not much use singing Rihanna to their baby!" Secondly, the babies were not exposed to any other stimuli. "Although their parents were in the room, they sat behind the babies, so their facial expressions could not influence the child's," Corbeil added. "Infants were also exposed to recordings, rather than a live performance, to ensure comparable performances for all children and no social interactions between performer and child." [...] The findings are important because mothers, and Western mothers in particular, speak much more often than they sing to their children, missing out on the emotion-regulatory properties of singing. The researchers believe that singing could be particularly useful for the parents who are challenged by adverse socio-economic or emotional circumstances. "Although infant distress signals typically prompt parental comforting interventions, they induce frustration and anger in some at-risk parents, leading to insensitive responding and, in the worst cases, to infant neglect or abuse," Peretz said. "At-risk parents within the purview of social service agencies could be encouraged to play vocal music to infants and, better still, to sing to them." biologynews.net
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High-Tech Methods Study Bacteria On The International Space Station
Where there are people, there are bacteria, even in space. But what kinds of bacteria are present where astronauts live and work? Researchers from NASA's Jet Propulsion Laboratory, Pasadena, California, in collaboration with colleagues at other institutions, used state-of-the-art molecular analysis to explore the microbial environment on the International Space Station. They then compared these results to the bacteria found in clean rooms, which are controlled and thoroughly cleaned laboratory environments on Earth. They report their findings in the open access journal Microbiome . Examining samples from an air filter and a vacuum dust bag from the space station, researchers found opportunistic bacterial pathogens that are mostly innocuous on Earth but can lead to infections that result in inflammations or skin irritations. In general, they found that the human skin-associated bacteria Corynebacterium and Propionibacterium (Actinobacteria) but not Staphylococcus were more abundant on the station than in Earth-based clean rooms. "Studying the microbial community on the space station helps us better understand the bacteria present there, so that we can identify species that could potentially damage equipment or pose harms to astronaut health. It also helps us identify areas that need more rigorous cleaning," said Kasthuri Venkateswaran, who led the research at JPL with collaborators Aleksandra Checinska, the study's first author, and Parag Vaishampayan. sciencedaily.com
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Chemistry
WHO Urged To Revisit Drinking Water Guidelines
The World Health Organization’s (WHO) drinking water guidelines for nine common toxic chemicals are inadequate and should be re-evaluated, according to a team of researchers led by Bibudhendra Sarkar at the Hospital for Sick Children in Toronto. The 2011 edition of the WHO’s drinking water quality guidelines were less restrictive for manganese, boron, mercury, molybdenum, nickel, nitrite, selenium and uranium and did not establish a guideline for aluminium. After examining the agency’s background documents explaining the rationale for the changes, Sarkar’s research team concluded that some of these modifications failed to account for the occurrence of such chemicals in drinking water, or key health studies from the last decade. For example, the scientists suggest that the removal of manganese from the 2011 guidelines is ‘especially worrisome’ because the decision was not grounded in the best science and could harm public health. Sarkar’s team references the fact that the WHO said it withdrew the 400μg/l drinking water guidelines for manganese because that figure is well above concentrations of the element normally found in drinking water, but the researchers note that manganese has been reported in greater concentrations in over 50 countries. Chronic manganese exposure has been linked to various neurological effects such as learning disabilities in children, Parkinson’s disease and cognitive decline in adults. rsc.org
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Scientists May Have Found The Earliest Evidence Of Life On Earth
When did life on Earth begin? Scientists have dug down through the geologic record, and the deeper they look, the more it seems that biology appeared early in our planet’s 4.5-billion-year history. So far, geologists have uncovered possible traces of life as far back as 3.8 billion years. Now, a controversial new study presents potential evidence that life arose 300 million years before that, during the mysterious period following Earth’s formation. The clues lie hidden in microscopic flecks of graphite—a carbon mineral—trapped inside a single large crystal of zircon. Zircons grow in magmas, often incorporating other minerals into their crystal structures of silicon, oxygen, and zirconium. And although they barely span the width of a human hair, zircons are nearly indestructible. They can outlast the rocks in which they initially formed, enduring multiple cycles of erosion and deposition. In fact, although the oldest rocks on Earth date back only 4 billion years, researchers have found zircons up to 4.4 billion years old. These crystals provide a rare glimpse into the first chapter of Earth’s history, known as the Hadean eon. “They are pretty much our only physical samples of what was going on on the Earth before 4 billion years ago,” says Elizabeth Bell, a geochemist at the University of California, Los Angeles (UCLA), and lead author of the new study, published online today in the Proceedings of the National Academy of Sciences. In the study, Bell and her colleagues examined zircons from the Jack Hills in Western Australia, a site that has yielded more Hadean samples than anywhere else on Earth, searching for inclusions of carbon minerals like diamonds and graphite. The mere presence of these minerals does not prove biology existed when the zircons formed, but it does provide the opportunity to look for chemical signs of life. The team eventually found small bits of potentially undisturbed graphite in one 4.1 billion-year-old crystal. The graphite has a low ratio of heavy to light carbon atoms—called isotopes—consistent with the isotopic signature of organic matter. “On Earth today, if you were looking at this carbon, you would say it was biogenic,” Bell says. “Of course, that’s more controversial for the Hadean.” sciencemag.org
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Earth Science
Tiny Bits Of Plastic Found In Table Salt In China
[...] When researchers analyzed fifteen brands of common table salt bought at supermarkets across China, they found among the grains of seasoning micro-sized particles of the common water bottle plastic polyethylene terephthalate, as well as polyethylene, cellophane, and a wide variety of other plastics. The highest level of plastic contamination was found in salt sourced from the ocean: The researchers measured more than 1,200 particles of plastic per lb of sea salt. The team, led by Huahong Shi of East China Normal University also found tiny particles of plastic in salt sourced from briny lakes, briny wells, and salt mines, although at lower levels—between 15 and 800 particles/ lb. Shi and colleagues argue that plastic contamination originates from the vast amount of plastic pollution floating around marine environments where sea salt is sourced. For instance, bits of plastics might abrade from larger objects, such as water bottles, dumped in the water or they might come from cosmetic products, such as face washes, that use plastic microbeads as exfoliants. The researchers add that other points of entry for plastic contamination are also possible, including during salt processing, drying, and packaging. Given that manufacturers typically extract sea salt from ocean water by evaporation—a process that leaves everything behind but water—microplastic contamination of sea salt is likely prevalent outside China as well, says Sherri Mason, who studies plastic pollution at the SUNY Fredonia. “Plastics have become such a ubiquitous contaminant, I doubt it matters whether you look for plastic in sea salt on Chinese or American supermarket shelves. I’d like to see some ‘me-too’ studies.” [...] Given that there are heavy metals and other chemicals of concern in plastic pollution, it’s wise to minimize the entry of plastic into the food chain, Mason adds. acs.org
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Historic Nitrate Levels Still Plague U.S. Rivers
During 1945 to 1980, nitrate levels in large U.S. rivers increased up to fivefold in intensively managed agricultural areas of the Midwest, according to a new U.S. Geological Survey study. In recent decades, nitrate changes have been smaller and levels have remained high in most of the rivers studied. The greatest increases in river nitrate levels coincided with increased nitrogen inputs from livestock and agricultural fertilizer, which grew rapidly from 1945 to 1980. In some urbanized areas along the East and West coasts during the same period, river nitrate levels doubled. Since 1980, nitrate changes have been smaller as the increase in fertilizer use has slowed in the Midwest and large amounts of farmland have been converted to forest or urban land along the East coast. "Long-term monitoring of 22 large U.S. rivers provides a rare glimpse into how water quality conditions have changed over the last 65 years," said Edward Stets, lead author of the study. "Although the greatest increases in nitrate concentrations occurred prior to 1980, levels have since remained high in most rivers. Unfortunately, there is no widespread evidence of improving conditions." High nitrate levels can lead to the formation of zones of low oxygen in coastal waters, which harms fisheries, recreational use, and ecological habitat, causing major economic impacts. High nitrate levels also pose a threat to drinking-water supplies, sometimes resulting in high water treatment costs, and can harm aquatic life. [...] Long-term monitoring of water quality is essential to track how changes in land use, climate, and water-quality management actions are impacting both local streams and rivers and valuable commercial and recreational fisheries in estuaries across the Nation. The USGS National Water-Quality Program is working on more detailed analysis of water quality trends within the past 10 to 50 years in small and large rivers across the Nation. enn.com
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Physics
China 'To Start Work On Super, Super-Collider By 2020'
China will begin work on the world's largest super-collider in 2020, state-run media reported Thursday, in an attempt to increase understanding of the Higgs boson, or "god particle". The facility, designed to smash subatomic particles together at enormous speed, will reportedly be at least twice the size of the Swiss-based CERN, where the Higgs boson was discovered. [...] As planned, the Chinese project will generate seven times the energy of the LHC, colliding electrons and protons at super high speeds to generate the elusive particles on an unprecedented scale. [...] At a time when austerity measures have led many developed nations to reduce research funding for projects without clear applications, China is pouring huge sums money into theoretical as well as practical science, hoping to become a world leader in fields from biology to cosmology. phys.org
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Swarming Fire Ants Show Solid And Liquid Properties
Aggregations of fire ants can, on a macroscopic scale, show some surprisingly classical material properties, such as viscoelasticity and flow, researchers in the US have demonstrated. The research gives, they say, a fascinating example of "active matter" – in which the individual elements are able to use energy and rearrange themselves – and could potentially provide insights for developing new materials. Fire ants are known for their ability to organize into remarkable macroscopic structures. They can link their legs together into elastic solids that can resist macroscopic applied loads or self-assemble into rafts to survive floods. They have also been seen to form liquid-like aggregations, in one remarkable case "dripping" from a tap. "Lots of people have looked at the ants as a biological entity," explains physicist Michael Tennenbaum of Georgia Institute of Technology in Atlanta. "But no-one has ever looked at the ants as a material." Ant gymnastics In the latest work, Tennenbaum and colleagues studied various macroscopic properties of such aggregations. They placed a lead sphere on top of an aggregation of the ants and calculated the aggregation's viscosity by measuring the speed at which the sphere sank through it. Next, the researchers placed the aggregation inside a rheometer, between two plates coated with Velcro. The ants gripped the Velcro tightly, meaning that rotation between the plates could be achieved only by shear of the aggregation. The researchers then applied a variable stress to the plates, finding similar – although not identical – viscosity. As expected, they also found that applying greater stress resulted in faster rotation (shear) between the plates, but the relationship was complex. At relatively low shear, for example, a greater increase in stress was required to produce the same increase in shear; whereas at high rates, increases in shear could be achieved with a smaller increase in stress. In the language of classical physics, the viscosity of the aggregation decreased as shear increased. This phenomenon, called shear-thinning, is commonly observed in conventional viscoelastic materials. "If you did this experiment with jelly, you would get very elastic behaviour at really small strains, but at large strains you would get flow," says Tennenbaum. Nevertheless, on a microscopic basis, the aggregation is nothing like a conventional viscoelastic material. physicsworld.com
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