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
Sun Experiences Seasonal Changes, New Research Finds
The Sun undergoes a type of seasonal variability with its activity waxing and waning over the course of nearly two years, according to a new study by a team of researchers led by the National Center for Atmospheric Research (NCAR). This behavior affects the peaks and valleys in the approximately 11-year solar cycle, sometimes amplifying and sometimes weakening the solar storms that can buffet Earth’s atmosphere. The quasi-annual variations appear to be driven by changes in the bands of strong magnetic fields in each solar hemisphere. These bands also help shape the approximately 11-year solar cycle that is part of a longer cycle that lasts about 22 years. “What we’re looking at here is a massive driver of solar storms,” said Scott McIntosh from NCAR’s High Altitude Observatory. “By better understanding how these activity bands form in the Sun and cause seasonal instabilities, there’s the potential to greatly improve forecasts of space weather events.” The overlapping bands are fueled by the rotation of the Sun’s deep interior, according to observations by the research team. As the bands move within the Sun’s northern and southern hemispheres, activity rises to a peak over a period of about 11 months and then begins to wane. [...]
“Much like Earth’s jet stream, whose warps and waves have had severe impact on our regional weather patterns in the past couple of winters, the bands on the Sun have very slow-moving waves that can expand and warp it, too,” said Robert Leamon from Montana State University. “Sometimes this results in magnetic fields leaking from one band to the other. In other cases, the warp drags magnetic fields from deep in the solar interior, near the tachocline, and pushes them toward the surface.”
The surges of magnetic fuel from the Sun’s interior catastrophically destabilize the corona, our star’s outermost atmosphere. They are the driving force behind the most destructive solar storms. astronomy
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How Quickly Does A Supernova Happen?
Our Sun will die a slow sad death, billions of years from now when it runs out of magic sunjuice. Sure, it’ll be a dramatic red giant for a bit, but then it’ll settle down as a white dwarf. Build a picket fence, relax on the porch with some refreshing sunjuice lemonade. Gently drifting into its twilight years, and slowly cooling down until it becomes the background temperature of the Universe. If our Sun had less mass, it would suffer an even slower fate. So then, unsurprisingly, if it had more mass it would die more quickly. In fact, stars with several times the mass of our Sun will die as a supernova, exploding in an instant. Often we talk about things that take billions of years to happen on the Guide to Space. So what about a supernova? Any guesses on how fast that happens? [...] Just like our Sun, [different kinds of supernovae] convert hydrogen into helium through fusion, releasing a tremendous amounts of energy which pushes against the star’s gravity trying to collapse in on itself. Once the massive star runs out of hydrogen in its core, it switches to helium, then carbon, then neon, all the way up the periodic table of elements until it reaches iron. The problem is that iron doesn’t produce energy through the fusion process, so there’s nothing holding back the mass of the star from collapsing inward. … and boom, supernova. The outer edges of the core collapse inward at 70,000 meters per second, about 23% the speed of light. In just a quarter of a second, infalling material bounces off the iron core of the star, creating a shockwave of matter propagating outward. This shockwave can take a couple of hours to reach the surface. As the wave passes through, it creates exotic new elements the original star could never form in its core. And this is where we get all get rich. All gold, silver, platinum, uranium and anything higher than iron on the periodic table of elements are created here. A supernova will then take a few months to reach its brightest point, potentially putting out as much energy as the rest of its galaxy combined. universetoday
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Explosive Culprit? Russian Fireball's Origins Found
A crackling fireball that exploded over Russia last year appears to share an orbit with a huge asteroid discovered in October 2014, a new study reports. The Kola fireball was spotted on April 19, 2014, as it lit up the night sky above the Kola Peninsula near the Finnish-Russian border. Its orbit is "disturbingly similar" to the asteroid 2014 UR116, slated to pass by the moon in 2017, the study authors said. [...] Josep Maria Trigo-Rodríguez, a researcher at the Institute of Space Sciences in Barcelona, Spain, led the international team of scientists who analyzed the meteorite's orbit. They calculated the fireball's size and path through Earth's atmosphere by examining its flight and the meteorite's final impact site. A computer model based on these figures was used to estimate the space rock's orbital path. The 1,100-pound (500 kilogram) meteorite is an ordinary H5 chondrite, a type of stony meteorite responsible for 31 percent of Earth's impacts. The fragments are called the "Annama meteorite" because the meteorite fell near the Annama River in Russia. The precise detective works suggests the fireball escaped from the innermost region of the asteroid belt, the study researchers reported. The rock has an elliptical orbit that is typical of the Apollo family of near-Earth orbiting asteroids, and it likely came from the same broad source region as the Lost City, Peekskill and Buzzard Coulee meteorites, the researchers said space.com
Biology
Purging A Virus From Organ Transplants
Human cytomegalovirus (HCMV) is an extremely common virus, which as other members of the herpes virus family causes life-long infections in humans. Most individuals are exposed to HCMV during childhood, yet symptoms can be easily fought off by a healthy immune system. However, infections can be life-threatening for individuals with defective immunity, for instance newborn babies, people with AIDS, or those taking immunosuppressive drugs following organ transplantation. Scientists at École Polytechnique Federale de Lausanne (EPFL) have discovered the molecular switch that allows HCMV to either lie dormant or reactivate its infection. The switch can be manipulated with simple drugs to force the virus out of dormancy, making it easy to target with antivirals. Published in eLife, the study shows how HCMV could be fought in high-risk patients and purged from organs before transplantation. HCMV infects 60% of the population in industrialized countries, and almost everybody in less affluent places. This virus persists for life by hiding in blood-making ("hematopoietic") stem cells, where it lies dormant and goes completely unrecognized. It occasionally reactivates in the descendence of these hematopoietic stem cells, but these bouts are rapidly tamed by the immune system. However, in people whose immune system has been compromised, e.g. by AIDS, and organ transplant recipients who have to take immunosuppressive drugs, HCMV reactivation can cause devastating symptoms. Throwing the switch The lab of Didier Trono at EPFL discovered a protein that switches HCMV between dormancy and reactivation. They found this protein to be bound to the HCMV genome in latently infected hematopoietic stem cells and, upon a variety of external stimuli, to undergo a modification that allows for viral activation. Furthermore, the researchers were able to control this switch with a drug called chloroquine, usually used against malaria. When they treated hematopoietic stem cells containing dormant HCMV with chloroquine, the virus reactivated and became exposed, opening the door to maneuvers aimed at eliminating virus-infected cells. The simplicity of the study's design underlies its enormous significance. On one hand, it sheds light on the molecular mechanism by which HCMV becomes dormant in hematopoietic stem cells, possibly offering insights into similar infections by other herpes viruses. On the other hand, the study provides a straightforward method for forcing HCMV out of dormancy in infected tissue. Coupled with a simultaneous dose of an antiviral, this could become a standard regimen for eradicating HCMV from high-risk patients and purging it from tissue before transplantation. biologynews
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Context-Specific Close-Range “Hoo” Calls In Wild Gibbons
Background Close range calls are produced by many animals during intra-specific interactions, such as during home range defence, playing, begging for food, and directing others. In this study, we investigated the most common close range vocalisation of lar gibbons (Hylobates lar), the ‘hoo’ call. Gibbons and siamangs (family Hylobatidae) are known for their conspicuous and elaborate songs, while quieter, close range vocalisations have received almost no empirical attention, perhaps due to the difficult observation conditions in their natural forest habitats. Results We found that ‘hoo’ calls were emitted by both sexes in a variety of contexts, including feeding, separation from group members, encountering predators, interacting with neighbours, or as part of duet songs by the mated pair. Acoustic analyses revealed that ‘hoo’ calls varied in a number of spectral parameters as a function of the different contexts. Males’ and females’ ‘hoo’ calls showed similar variation in these context-specific parameter differences, although there were also consistent sex differences in frequency across contexts. Conclusions Our study provides evidence that lar gibbons are able to generate significant, context-dependent acoustic variation within their main social call, which potentially allows recipients to make inferences about the external events experienced by the caller. Communicating about different events by producing subtle acoustic variation within some call types appears to be a general feature of primate communication, which can increase the expressive power of vocal signals within the constraints of limited vocal tract flexibility that is typical for all non-human primates. In this sense, this study is of direct relevance for the on-going debate about the nature and origins of vocally-based referential communication and the evolution of human speech. biomedcentral
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Being Born In Lean Times Is Bad News For Baboons
The saying ”what doesn’t kill you makes you stronger” may not hold up to scientific scrutiny. Baboons born in times of famine are more vulnerable to food shortages later in life, finds a new study. The findings are important because they help explain why people who are malnourished in early childhood often experience poor health as adults. After the plains of southern Kenya experienced a severe drought in 2009 that took a terrible toll on wildlife, researchers at Duke and Princeton Universities looked at how 50 wild baboons coped with the drought, and whether the conditions they faced in infancy played a role. [...] During the 2009 drought, baboons born during low rainfall years were 60 percent less likely to become pregnant, whereas pregnancy rates dipped by only 10 percent for females born during normal rainfall years. Drought babies born to higher-status mothers were less affected by the 2009 event. [...] It might be that baboons born to higher-ranked moms have better access to food, or suffer lower levels of social stress,” Alberts said. The findings help explain why people who are malnourished in early childhood go on to have higher rates of obesity, diabetes and heart disease as adults. duke.edu
Chemistry
Erupting Electrodes: How Recharging Leaves Behind Microscopic Debris Inside Batteries
[...] As anyone with a dying cell phone knows, it would be nice if rechargeable batteries held more power, lasted longer and were cheaper. Solving these problems could also make electric vehicles and renewable energy more attractive. Using metals such as magnesium or aluminum in place of lithium could improve batteries life and cost, but research and development into non-lithium rechargeables lags far behind the common commercial lithium ion ones. To speed up development of rechargeable batteries, DOE funded the Joint Center for Energy Storage Research, a collaboration of several national labs, universities and private sector companies. Multidisciplinary teams of scientists explore a variety of problems, hoping to overcome them by understanding the underlying chemical principles. For instance, rechargeable batteries suffer from the growth of dendrites, microscopic, pin-like fibers that afflict battery electrodes. Recently, JCESR researchers led by PNNL discovered a way to eliminate dendrites in lithium batteries by using a special electrolyte. To better understand how dendrites form and can be prevented at the microscopic level, another JCESR team led by PNNL's Nigel Browning devised a microscope that could examine a full working battery in action. Unlike other views of the inner workings of batteries at high magnification, most of which use only part of a battery or have to study them under pressures not typically used in batteries, the Browning team created a complete functioning battery cell under normal operating conditions. "This is very exciting work," said first author Layla Mehdi. "We constructed a real working battery inside the transmission electron microscope. The advantage is that we can directly observe all the chemical reactions at the electrolyte-electrode interface in real time, as they are happening during cycling of the battery." sciencedaily
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Organic Molecules Found Circling Nearby Star
Astronomers have detected chemical precursors of building blocks of life in the large disk of dust and gas whirling around a young nearby star. These complex organic molecules, two forms of cyanide and one chemically related compound, likely formed after the protoplanetary disk collapsed, the researchers say. The same chemicals are found in roughly similar proportions in comets circling our sun, which may have brought them to Earth billions of years ago. “We know that the solar system isn’t unique in its number of planets or abundance of water,” says Karin Öberg, an astrochemist at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts. “Now we know that we’re not unique in organic chemistry. From a life in the universe point of view, this is great news.” The star the researchers studied, dubbed MWC 480, lies about 450 light-years from Earth in the constellation Taurus. About 1 million years old, the star—which is about 1.8 times the mass of our sun—is surrounded by a disk of dust and gas that altogether contains approximately two-tenths a solar mass, Öberg says. The team’s observations, as well as previous studies, haven’t spotted any nascent planets inside the protoplanetary disk, she notes: Either those measurements haven’t had high enough resolution to discern the objects, or it’s too early in the star’s evolution for such bodies to have formed. What the team has seen, however, are the chemical signs of three complex organic molecules in the cyanide family—an astronomical first, Öberg says. Although astronomers have spotted hydrogen cyanide in other star systems, the two more complicated chemical relatives detected in this study have never been seen in a protoplanetary disk. Those substances—hydrogen cyanide (HCN), methyl cyanide (CH3CN), and cyanoacetylene (HC3N)—were discerned through the microwave radiation they emitted at several millimeter-scale wavelengths. sciencemag
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B.O. Gives Up Its Stinky Secrets
Body odor. The smell of B.O. is unmistakable. And the culprit behind that signature stench is a molecule called thioalcohol. Our noses are so attuned to it, we can pick up quantities as small as one part per trillion. But here's the mystery: How does that stinky substance get there in the first place? Well, it turns out bacteria named Staphylococcus hominis is the major perpetrator, along with a few of its relatives. Their genes code for enzymes that snip the molecules in our sweat to pieces—creating the offensive thioalcohols, along with bits of food for the bacteria. Hey, bacteria gotta eat, too, right? When innocuous E. coli bacteria were given the genes that our B.O. perpetrators have naturally, they, too, could achieve the stank. These findings were presented at the annual meeting of the Society for General Microbiology, in Birmingham, in the U.K. [Daniel Bawdon et al, Battling body odour: transport and catabolism of malodour precursors by the underarm microbiota] Not surprisingly, this work was partially funded by Unilever. Because now that we've identified these microbial targets, the researchers say, it might be possible to design more effective deodorants. Which, instead of crippling all underarm bacteria, dispatch only the most dastardly denizens. Smells like profit to me. scientificamerican
Earth Science
Mercury Levels In Arctic Birds Found Increasing Over The Past 130 Years
Alarm bells are ringing for Arctic wildlife with the discovery that mercury levels in the feathers of ivory gulls have increased almost 50-fold. University of Saskatchewan biologists studied the feathers of museum specimens spanning a 130-year period. Lead researcher Dr Alex Bond told BBC News, “We’re concerned because the mercury’s going up but their diet hasn’t changed over the 130 years we’ve studied. It’s gone up 45 times, which is twice the average for an animal species in the Arctic.” Scientists believe the increase in mercury pollutants could partially explain the rapid decrease in population. Ivory gull populations in Canada have decreased by more than 80 per cent since the 1980s, leading to them being officially recognised as endangered in Canada. Numbers of the birds are also falling elsewhere — the International Union for Conservation of Nature has classified the gull as “Near Threatened”. Mercury pollution is expected to continue to rise particularly at high latitudes due to increasing emissions and global change. enn
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China Blocks Yangtze Dam Project, Activists Say
The Chinese Ministry of Environmental Protection has issued an order preventing dam-building on a stretch of the upper Yangtze River, according to environmental activists, that will result in the scrapping of a proposed hydroelectric dam near the western metropolis of Chongqing that had been opposed for years by environmentalists. The Xiaonanhai Dam would have cost billions of dollars to build and operate, and it was supported by Bo Xilai, the former Chongqing party chief who was sentenced to life in prison in 2013 for corruption. The dam would have been Chongqing’s largest infrastructure project. Environmentalists said the dam would have destroyed a protected area of the river that had been established by officials as an ecology-friendly counterpoint to the construction of the Three Gorges Dam, farther downstream and the world’s largest hydropower project. The protected area has been a haven for a wide variety of fish — some of which are rare or endangered — that need access to rapidly flowing waters. Sections of the Ministry of Environmental Protection’s order were posted on microblogs this week by environmentalists who had gotten copies of the document. The order was dated March 30. Zhang Boju, an advocate at Friends of Nature, a nongovernmental organization that has been a persistent critic of the dam, said in a telephone interview that he and other environmentalists had posted sections of the document online and that he was certain they were authentic. The ministry declined to comment on the order. nyt
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Ocean of Acid Blamed For Earth's 'Great Dying'
Death by acid was the fate of the sea monsters that perished in Earth's biggest mass extinction, some 251 million years ago, a new study finds. Nearly every form of ocean life disappeared during this "Great Dying" at the end of the Permian period, when more than 90 percent of all marine species vanished, from the scorpionlike predators called eurypterids to various types of trilobites, some with alienlike stalked eyes. It's the closest Earth has ever come to completely losing its fish, snails, sea plankton and other marine creatures. Some 70 percent of animals and plants on land died off at the same time. Now, there is direct evidence that ocean acidification dealt the final blow to species already suffering from these huge environmental changes. By analyzing boron embedded in limestone from the Permian and Triassic periods, researchers discovered an abrupt shift in ocean pH levels. The change in acidity corresponds to a drop in surface ocean pH levels of 0.6 to 0.7 pH units that lasted about 10,000 years. In comparison, modern ocean pH levels have fallen by 0.1 pH units since the Industrial Revolution, a 30 percent increase in acidity. livescience
Physics
Absence Of Gravitational-Wave Signal Extends Limit On Knowable Universe
Imagine an instrument that can measure motions a billion times smaller than an atom that last a millionth of a second. Fermilab's Holometer is currently the only machine with the ability to take these very precise measurements of space and time, and recently collected data has improved the limits on theories about exotic objects from the early universe [...] The Holometer experiment, based at the Department of Energy's Fermilab, is sensitive to gravitational waves at frequencies in the range of a million cycles per second. Thus it addresses a spectrum not covered by experiments such as the Laser Interferometer Gravitational-Wave Observatory, which searches for lower-frequency waves to detect massive cosmic events such as colliding black holes and merging neutron stars. The Holometer is composed of two Michelson interferometers that each split a laser beam down two 40-meter arms. The beams reflect off the mirrors at the ends of the arms and travel back to reunite. Passing gravitational waves alter the lengths of the beams' paths, causing fluctuations in the laser light's brightness, which physicists can detect. The Holometer team spent five years building the apparatus and minimizing noise sources to prepare for experimentation. Now the Holometer is taking data continuously, and with an hour's worth of data, physicists were able to confirm that there are no high-frequency gravitational waves at the magnitude where they were searching. The absence of a signal provides valuable information about our universe. Although this result does not prove whether the exotic objects exist, it has eliminated the region of the universe where they could be present. phys.org
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Physicists Create Ultrasensitive Magnetometer
Synthetic diamonds with nitrogen vacancies (NVs) have long held promise as the basis for efficient, portable magnetometers (magnetic-field detectors). A diamond chip about 1/20 the size of a thumbnail could contain trillions of the NVs, each capable of performing its own magnetic-field measurement. The problem has been aggregating all those measurements. Probing a NV requires zapping it with laser light, which it absorbs and re-emits. The intensity of the emitted light carries information about the vacancy’s magnetic state. [...] “Only a small fraction of the light is absorbed. Most of it just goes straight through the diamond. We gain an enormous advantage by adding the prism facet to the corner of the diamond and coupling the laser into the side. All of the light that we put into the diamond can be absorbed and is useful,” said study lead author Hannah Clevenson, a graduate student at MIT. The MIT team calculated the angle at which the laser beam should enter the crystal so that it will remain confined, bouncing off the sides in a pattern that spans the length and breadth of the crystal before all of its energy is absorbed. “You can get close to a meter in path length. It’s as if you had a meter-long diamond sensor wrapped into a few millimeters,” Prof Englund said. sci-news
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Synopsis: Sorting Carbon Nanotubes With Light
Single-walled carbon nanotubes possess many industrially useful properties such as high thermal and electricity conductivity. These, and other properties, depend on the nanotubes’s chirality—the angle at which the two-dimensional lattice of carbon atoms “wraps” to form the nanotube. But batches of nanotubes are usually synthesized with a distribution of chiralities, while many nanotubes with the same chirality are needed for applications, like chemical and optical sensors. Now, researchers in Satoshi Kawata’s group at Osaka University in Japan have shown that a low-power laser can effectively sort nanotubes according to chirality. Their method is potentially less expensive and able to select for a wider range of chiralities than other approaches. Kawata and his colleagues filled a glass microcapillary tube with solution containing suspended nanotubes with a spread of chiralities. The researchers then shone a tunable red laser into one end of the tube for several hours. When light from the laser was in resonance with a nanotube’s band-gap energy, it scattered more readily, imparting a force large enough to move the particle. Since band-gap energy is related to chirality, Kawata and his team were able to push nanotubes with a specific chirality toward the other end of the tube by tuning their laser to the appropriate wavelength. Kawata’s technique is inexpensive and relatively fast and only selects intact nanotubes, since damaged nanotubes don’t have the necessary optical resonances. Kawata and his team were, in some cases, able to double the relative concentration of nanotubes with a particular chirality. And they suggest that chiral purities of up to 100% could be achieved if they use two or more counterpropagating laser beams with different wavelengths to push different chiralities in opposite directions, physics.aps