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
Teeny Supermassive Black Hole
At the heart of every big galaxy sits a supermassive black hole. These leviathans are essentially pits in the fabric of spacetime. They contain millions to billions of times the mass of the Sun, yet squash all their mass deep inside a boundary whose size is on par with scales from the solar system. (The event horizon of the Milky Way’s central black hole is only 20% as wide as Mercury’s orbit, in case you’re curious.) These beasts don’t dwell just in big galaxies, however. Some dwarf galaxies also have supermassive black holes at their centers. Last year, for example, we reported on the discovery of 151 active black holes in these runt galaxies. At the time, Amy Reines (then at NRAO) and her team could only determine masses for about two dozen of the black holes, which weighed in at 80,000 to 6.3 million solar masses. As part of the ongoing investigation of the other 100-plus objects, Vivienne Baldassare (University of Michigan), Reines, and their colleagues have now determined the mass of the black hole sitting in the dwarf disk galaxy SDSS J1523+1145. (The team calls the stellar city RGG 118, for the surname initials of the three authors of the previous study.) And in the words of coauthor Elena Gallo (also at Michigan), this supermassive black hole is downright “teeny.” Small Supermassive Black Hole The team used the 6.5-meter Clay Telescope in Chile and the Chandra X-ray Observatory to study the black hole’s energy output and clock how fast gas is moving near it. Astronomers calculate a black hole’s mass using the gas’s velocity: the gas emits radiation at certain wavelengths, and its whiplash speed smears out these spectral lines. The lines’ width tells astronomers how fast the gas is moving and, thus, how massive the black hole is. The team estimates that RGG 118’s central black hole has a mass between 27,000 and 62,000 Suns — so, about 50,000. That makes it the smallest beast ever found in a galaxy’s nucleus. skyandtelescope.com
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How Much Contamination Is OK On NASA's Mars 2020 Rover?
[...] Concern about carrying contaminating organic material from Earth to Mars is not a new one; scientists and engineers have discussed this throughout the history of space exploration. Since there are remnants of microbial life, both dead and alive, everywhere on Earth, it is impossible to build spacecraft within the Earth's biosphere that are strictly biologically clean. Many of the panel's recommendations build upon processes utilized by previous missions, such as utilizing witness plates and blanks to track potential contamination. Witness plates are materials that have defined open and closed periods at points throughout the mission, exposing and protecting them from environmental conditions. The plates serve as a background for the study of samples. "By using a series of witness plates that are opened and closed at different times, it is possible to generate an understanding of the history of environmental contaminants as a function of time — and for a mission like Mars 2020, this could change significantly with time," said David Beaty, committee member and chief scientist for the Mars Exploration Directorate at NASA's Jet Propulsion Laboratoryin Pasadena, California. space.com
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Biology
Octopus Genome Reveals Cephalopod Secrets
An international team of scientists has sequenced the genome of an octopus, bringing researchers closer to discovering the genes involved in the creature’s unusual biology, including its ability to change skin color and texture and a distributed brain that allows its eight arms to move independently. The team that sequenced and annotated the genome of the common California two-spot octopus (Octopus bimaculoides) was led by scientists from UC Berkeley, the Okinawa Institute of Science and Technology Graduate University (OIST) and the University of Chicago. The researchers will publish their findings in the Aug. 13 issue of the journal Nature. The researchers discovered striking differences between the genomes of the octopus and other invertebrates, including widespread rearrangements of genes and a dramatic expansion of a family of genes involved in neuronal development that was once thought to be unique to vertebrates.
“The octopus nervous system is organized in a totally different way from ours: The central brain surrounds the esophagus, which is typical of invertebrates, but it also has groups of neurons in the arms that can work relatively autonomously, plus huge optic lobes involved in vision,” said Daniel Rokhsar, who co-led the project along with Clifton Ragsdale, of the University of Chicago. “The sequencing was an opportunity to look at the genome and see what we can learn about the unique brain and morphology of the octopus.”
berkeley.edu
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Humans Responsible For Demise Of Gigantic Ancient Mammals
Early humans were the dominant cause of the extinction of a variety of species of giant beasts, new research has revealed. Scientists at the universities of Exeter and Cambridge claim their research settles a prolonged debate over whether mankind or climate change was the dominant cause of the demise of massive creatures in the time of the sabretooth tiger, the woolly mammoth, the woolly rhino and the giant armadillo. Known collectively as megafauna, most of the largest mammals ever to roam the earth were wiped out over the last 80,000 years, and were all extinct by 10,000 years ago. [...] The researchers ran thousands of scenarios which mapped the windows of time in which each species is known to have become extinct, and humans are known to have arrived on different continents or islands. This was compared against climate reconstructions for the last 90,000 years. Examining different regions of the world across these scenarios, they found coincidences of human spread and species extinction which illustrate that man was the main agent causing the demise, with climate change exacerbating the number of extinctions. However, in certain regions of the world - mainly in Asia - they found patterns which patterns were broadly unaccounted for by either of these two drivers, and called for renewed focus on these neglected areas for further study.
Lewis Bartlett, a researcher from the University of Exeter's Centre for Ecology and Conservation, said: "As far as we are concerned, this research is the nail in the coffin of this 50-year debate - humans were the dominant cause of the extinction of megafauna. What we don't know is what it was about these early settlers that caused this demise. Were they killing them for food, was it early use of fire or were they driven out of their habitats? Our analysis doesn't differentiate, but we can say that it was caused by human activity more than by climate change. It debunks the myth of early humans living in harmony with nature."
biologynews.net
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Chemistry
Chemical Curbs Cow Farts
Know what really stinks? The gas that livestock such as cattle release during digestion. These animals produce a quarter of the anthropogenic methane in the U.S. What doesn’t stink is that Pennsylvania State University researchers, led by Alexander N. Hristrov, have now demonstrated that feeding 3-nitrooxypropanol (3NOP) to dairy cows over a 12-week period reduces the animals’ methane emissions by 30%[...]. 3NOP inhibits methyl coenzyme-M reductase, an enzyme used by bacteria in a cow’s gut. These symbiotic bacteria produce methane when they help cows digest grass and other fiber-rich foods in the animals’ diet. To test the possibility of mitigating this production without disrupting a cow’s digestion, Hristov and his colleagues mixed additives containing three different concentrations of 3NOP as well as a placebo additive into cattle feed. Then they administered it to 48 Holstein cows for three months. The rate of methane emission fell in all the animals, except for those receiving the placebo. Scientists have discovered several other methane production inhibitors, but 3NOP appears to be the first to achieve a meaningful effect while being safe for cows’ health and the environment scientificamerican.com
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Chemical Treatment Transforms Skin Cells Into Neurons
Two teams of researchers have found different ways to perform the same biological identity swap: turning skin cells into neurons. Both approaches, which involve merely adding a few chemicals to cells, could lead to new ways to treat a person’s disease using cells from their own body. Most of the ways scientists turn one type of cell into another, or into more basic stem cells, depend on adding genes to the original cells. But this gene insertion approach has drawbacks. Its intricate steps are time-consuming, and there’s always a chance the added gene could land somewhere on a chromosome that activates a cancer-causing gene. The new approaches [...] take a less invasive route. The key, explains Gang Pei, a biochemist at the Shanghai Institutes for Biological Sciences in China, and a co-author on one of the studies, are so-called small molecule chemicals that can slip into a cell, enter the DNA-containing nucleus, and alter the activity of a gene. Pei and his team probed thousands of chemicals to identify those that could convert one cell type into another and found a specific recipe of molecules that essentially switched off skin cell genes in human cells and turned on neuron genes. When the group added seven small molecules denoted as VCRFSGY (valproic acid, CHIR99021, Repsox, Forskolin, SP600125, GO6983, and Y-27632), to a petri dish of human skin cells, the cells transformed into mature, functional neurons over the course of a few weeks. VCRFSGY works in stages. The initial four chemicals, VCRF, start by changing physical traits, acting on a gene called Tuj1, which is specifically active in neurons. But VCRF alone leaves the cell in an unhappy medium: not a true skin cell and not yet a neuron either. The rest of the chemicals—SGY—round out the conversion by amplifying the neuronal development initiated by VCRF. Not only did the resulting cells look like neurons, they acted like them, too: They were able to fire action potentials, a key component that underlies the basics of neuron communication, the team reports. sciencemag.org
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Earth Science
US EPA Proposes Regulations To Reduce Methane Emissions From Landfills
As part of the Administration's Climate Action Plan – Strategy to Reduce Methane Emissions, the U.S. Environmental Protection Agency (EPA) issued two proposals to further reduce emissions of methane-rich gas from municipal solid waste (MSW) landfills. Under today’s proposals, new, modified and existing landfills would begin collecting and controlling landfill gas at emission levels nearly a third lower than current requirements. Methane is a potent greenhouse gas with a global warming potential more than 25 times that of carbon dioxide. Climate change threatens the health and welfare of current and future generations. Children, older adults, people with heart or lung disease and people living in poverty may be most at risk from the health impacts of climate change. In addition to methane, landfills also emit other pollutants, including the air toxics benzene, toluene, ethylbenzene and vinyl chloride. Municipal solid waste landfills receive non-hazardous wastes from homes, businesses and institutions. As landfill waste decomposes, it produces a number of air toxics, carbon dioxide, and methane. MSW landfills are the third-largest source of human-related methane emissions in the U.S., accounting for 18 percent of methane emissions in 2013 – the equivalent of approximately 100 million metric tons of carbon dioxide pollution. Combined, the proposed rules are expected to reduce methane emissions by an estimated 487,000 tons a year beginning in 2025 – equivalent to reducing 12.2 million metric tons of carbon dioxide, or the carbon pollution emissions from more than 1.1 million homes. EPA estimates the climate benefits of the combined proposals at nearly $750 million in 2025 or nearly $14 for every dollar enn.com
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Glass Paint: Secret To Keeping Metal Roofs Cool On Sunny Days
Scientists have created a glass paint that can bounce sunlight off metal roofs and keep them at air temperature. This is no minor feat. The sun can heat metal surfaces so much that playground slides or stadium bleachers can become too hot to use. The new paint has another potential upside. Since it’s almost completely inorganic—a mixture of silica, the main ingredient in glass, and silicon rubber—it doesn’t degrade in ultraviolet light and can last much longer than typical polymer-based coatings. “It’s almost like painting a rock on top of your metal. And this is going to last not tens of years but maybe hundreds of years,” says Jason Benkoski, senior scientist at Johns Hopkins University Applied Physics Laboratory. He presented his team’s work Sunday at a conference of the American Chemical Society in Boston. nationalgeographic.com
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Physics
Molecular Scientists Unexpectedly Produce New Type Of Glass
Their unforeseen discovery, reported in a paper published in the Proceedings of the National Academy of Sciences and chosen by Science as an editor's choice paper in Materials Science, could offer a simple way to improve the efficiency of electronic devices such as light-emitting diodes, optical fibers and solar cells. It also could have important theoretical implications for understanding the still surprisingly mysterious materials called glasses. "This is a big surprise," de Pablo said. "Randomness is almost the defining feature of glasses. At least we used to think so. What we have done is to demonstrate that one can create glasses where there is some well-defined organization. And now that we understand the origin of such effects, we can try to control that organization by manipulating the way we prepare these glasses." [...] The scientists grew the glass by vaporizing large organic molecules in a high vacuum and depositing them slowly, thin layer by thin layer, onto a substrate at a precisely controlled temperature. When the sample was thick enough, they analyzed it using spectroscopic ellipsometry—a technique that measures the way incident light or laser radiation interacts with the material being investigated. "Our collaborators saw some intriguing peaks in these materials," de Pablo said, "and those appear when you have some distinct molecular orientation in the material." The researchers could not originally explain the origin of the peaks, or why their appearance depended on the temperature at which the glass was formed. However, when the group ran computer simulations of the experiments, the same signatures of orientation appeared. A significant fraction of the molecules in the glass were aligning themselves in concert. The question was, why? The answer, the scientists discovered, lay in the way the material was created. In liquids—and glass is a type of liquid—the molecules at the surface interact with molecules in the air, sometimes causing them to pack together and line up differently than the randomly arrayed molecules in the bulk of the liquid. The vapor deposition process used in the experiments amounts to laying down one "surface" on top of another. The molecules in each layer get "trapped" in the orientation they had when they were truly, however briefly, on the surface. phys.org
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Engineers 'Sandwich' Atomic Layers To Make New Materials For Energy Storage
The scientists whose job it is to test the limits of what nature—specifically chemistry— will allow to exist, just set up shop on some new real estate on the Periodic Table. Using a method they invented for joining disparate elemental layers into a stable material with uniform, predictable properties, Drexel University researchers are testing an array of new combinations that may vastly expand the options available to create faster, smaller, more efficient energy storage, advanced electronics and wear-resistant materials. [...] "By 'sandwiching' one or two atomic layers of a transition metal like titanium, between monoatomic layers of another metal, such as molybdenum, with carbon atoms holding them together, we discovered that a stable material can be produced," Anasori said. "It was impossible to produce a 2-D material having just three or four molybdenum layers in such structures, but because we added the extra layer of titanium as a connector, we were able to synthesize them." The discovery, which was recently published in the journal ACS Nano, is significant because it represents a new way of combining elemental materials to form the building blocks of energy storage technology—such as batteries, capacitors and supercapacitors, as well as superstrong composites—like the ones used in phone cases and body armor. Each new combination of atom-thick layers presents new properties and researchers suspect that one, or more, of these new materials will exhibit energy storage and durability properties so disproportional to its size that it could revolutionize technology in the future. phys.org
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