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Rostov-na-Donu, Russia

News Article
Site: http://www.nature.com/nature/current_issue/

Elite ski jumpers rely on extreme balance and power to descend the steep slopes that allow them to reach up to 100 kilometres per hour. But the US Ski and Snowboard Association (USSA) is seeking to give its elite athletes an edge by training a different muscle: the mind. Working with Halo Neuroscience in San Francisco, California, the sports group is testing whether stimulating the brain with electricity can improve the performance of ski jumpers by making it easier for them to hone their skills. Other research suggests that targeted brain stimulation can reduce an athlete’s ability to perceive fatigue1. Such technologies could aid recovery from injury or let athletes try 'brain doping' to gain a competitive advantage. Yet many scientists question whether brain stimulation is as effective as its proponents claim, pointing out that studies have looked at only small groups of people. “They’re cool findings, but who knows what they mean,” says cognitive psychologist Jared Horvath at the University of Melbourne in Australia. The USSA is working with Halo to judge the efficacy of a device that delivers electricity to the motor cortex, an area of the brain that controls physical skills. The company claims that the stimulation helps the brain to build new connections as it learns a skill. It tested its device in an unpublished study of seven elite Nordic ski jumpers, including Olympic athletes. Four times per week, for two weeks, the skiers practised jumping onto an unstable platform. Four athletes received transcranial direct-current stimulation (tDCS) as they trained; the other three received a sham procedure. The stimulation ultimately improved the athletes' jumping force by 70% and their coordination by 80%, compared with the sham group, Halo announced in February. Troy Taylor, high-performance director for the USSA, is encouraged by the results — but concedes that they are preliminary. Another study, presented on 7 March at the Biomedical Basis of Elite Performance meeting in Nottingham, UK, suggests that tDCS may reduce the perception of fatigue. Sports scientist Lex Mauger of the University of Kent in Canterbury, UK, and his colleagues found that stimulating the motor-cortex region that controls leg function allows cyclists to pedal longer without feeling tired. The researchers stimulated the brains of 12 untrained volunteers before directing the athletes to pedal stationary bicycles until they were exhausted. Every minute, they asked the cyclists to rate their level of effort. Volunteers who received tDCS were able to pedal two minutes longer, on average, than were those who were given a sham treatment. They also rated themselves as less tired. But there was no difference in heart rate or the lactate level in the muscles between the treatment and control groups. This suggests that changes in brain perception, rather than muscle pain or other body feedback, drove the improved performance. Alexandre Okano, a biological engineer at Federal University of Rio Grande do Norte in Brazil, found similar increases in cyclists’ performance when he stimulated the brain’s temporal cortex, which is involved in body awareness and in automatic functions such as breathing2. This suggests that the temporal and motor cortices are connected in ways that are not understood, or that tDCS does not target locations in the brain precisely, Okano says. These results support the notion that the brain manages exertion by collating feedback from the body and then slowing muscles to prevent fatigue, says Dylan Edwards, a neurophysiologist at Burke Medical Research Institute in White Plains, New York3. “Even when you think you’re exercising as hard as you can, there is always some reserve of ability,” he says. But Horvath cautions that little is known about the long-term effects of stimulating the brain. And others are sceptical of the technique’s potential to increase performance. Vincent Walsh, a neuroscientist at University College London, notes that the methods used in tDCS studies often differ between research groups — and might not always be optimized. For instance, the fairly intense amount of electricity that Mauger's team used has been shown to sometimes have complex and unintended effects on the brain's activity4. Replicating such experiments is difficult because of variations in how people respond to brain stimulation. Some people do not respond at all; others might respond only when stimulated in a certain way. And even an individual’s response can differ from day to day. Edwards says that it is important to map these differences if tDCS is to be used therapeutically or for other purposes. “We’re moving toward customized prescription of brain stimulation,” he says. Nonetheless, the use of tDCS in sports is only likely to increase. Stimulating the motor cortex, for instance, seems to increase dexterity, so videogamers have been quick to take up the technique. And it is increasingly easy to acquire stimulation devices; Halo has begun to market its equipment for the express purpose of increasing athletic performance. Taylor compares the use of brain stimulation by athletes to eating carbohydrates ahead of an athletic event, in the hopes of boosting endurance. “It piggybacks on the ability to learn,” he says. “It's not introducing something artificial into the body.” But Edwards worries that the availability of tDCS devices will tempt athletes to try “brain doping”, in part because there is no way to detect its use. “If this is real,” he says, “then absolutely the Olympics should be concerned about it.”

News Article
Site: http://www.nature.com/nature/current_issue/

Astronomers have discovered a white dwarf star that has an atmosphere made almost entirely of oxygen — the first of its kind to be discovered. White dwarfs are the dense cores that get left behind when a relatively small star's nuclear fuel runs out and it sheds some of its outer layers. Usually their atmospheres are made of hydrogen or helium, because these light elements float to the surface. By analysing light gathered by the Sloan Digital Sky Survey telescope, Kepler de Souza Oliveira Filho at the Federal University of Rio Grande do Sul in Porto Alegre, Brazil, and his colleagues identified a white dwarf that has been stripped of its light elements. This has left it with an atmosphere containing mostly oxygen, with traces of neon and magnesium. A violent pulse of burning carbon from inside the star or a fiery merger with a companion white dwarf could have burned off the outer layers, suggest the authors.

News Article | April 2, 2016
Site: http://www.techtimes.com/rss/sections/science.xml

Astronomers have discovered a white dwarf star that has 99.9 percent pure oxygen atmosphere. The presence of an ancient sun that is able to live for so long, causing its outermost layer to consist of only pure oxygen, was just a theory before the white dwarf star was discovered. Small stars that have less than 10 times the mass of the sun become white dwarfs when they shed their outer layers, as the end of their lifespan nears. Ideally, due to high gravity, lighter elements of the star rise to the surface, while the heaviest elements descend to its dense core. But in the case of this white dwarf star, also known as SDSS J124043.01+671034.68, the outer atmosphere is composed of more than 99.9 percent of pure oxygen. The expected surface helium and hydrogen are absent. It only has few traces of magnesium, neon, and silicon. Astronomers cannot provide an exact answer to how it all happened but they speculated that the missing elements were stripped off the star's surface over time. Souza Oliviera Kepler of Federal University of Rio Grande do Sul in Brazil said their discovery of the star was unexpected. SDSS J124043.01+671034.68 or "Dox" is the first ever recorded star that underwent such process. "We had no idea anything like it could even exist, that made it all the more difficult to find," Kepler said. If it indeed underwent "stripping," the astronomers are still baffled as to how it could have happened. Kepler and his team offer several theories. They are considering the possibility that Dox is part of a binary star system, and its resultant interaction with another star helped peel away the missing atmospheric elements and leaving behind only the oxygen envelope on its surface. It could also be due to internal process within the star. Massive pulses of carbon burning at the core could have flared outwards, taking with it the lighter surface elements. Kepler believes their discovery is crucial in understanding the process of stellar evolution, particularly the binary star systems. In February 2015, astronomers discovered the first double-degenerate binary star, Henize 2-428, which can merge in 700 million years and trigger a supernova event. The findings of Kepler and his colleagues were published in Science.

News Article
Site: http://news.mit.edu/topic/mitchemistry-rss.xml

Scientists at MIT and the University of Texas at Arlington (UTA) have developed a new type of microscopy that can image cells through a silicon wafer, allowing them to precisely measure the size and mechanical behavior of cells behind the wafer. The new technology, which relies on near-infrared light, could help scientists learn more about diseased or infected cells as they flow through silicon microfluidic devices. “This has the potential to merge research in cellular visualization with all the exciting things you can do on a silicon wafer,” says Ishan Barman, a former postdoc in MIT’s Laser Biomedical Research Center (LBRC) and one of the lead authors of a paper describing the technology in the Oct. 2 issue of the journal Scientific Reports. Other lead authors of the paper are former MIT postdoc Narahara Chari Dingari and UTA graduate students Bipin Joshi and Nelson Cardenas. The senior author is Samarendra Mohanty, an assistant professor of physics at UTA. Other authors are former MIT postdoc Jaqueline Soares, currently an assistant professor at Federal University of Ouro Preto, Brazil, and Ramachandra Rao Dasari, associate director of the LBRC. Silicon is commonly used to build “lab-on-a-chip” microfluidic devices, which can sort and analyze cells based on their molecular properties, as well as microelectronics devices. Such devices have many potential applications in research and diagnostics, but they could be even more useful if scientists could image the cells inside the devices, says Barman, who is now an assistant professor of mechanical engineering at Johns Hopkins University. To achieve that, Barman and colleagues took advantage of the fact that silicon is transparent to infrared and near-infrared wavelengths of light. They adapted a microscopy technique known as quantitative phase imaging, which works by sending a laser beam through a sample, then splitting the beam into two. By recombining those two beams and comparing the information carried by each one, the researchers can determine the sample’s height and its refractive index — a measure of how much the material forces light to bend as it passes through. Traditional quantitative phase imaging uses a helium neon laser, which produces visible light, but for the new system the researchers used a titanium sapphire laser that can be tuned to infrared and near-infrared wavelengths. For this study, the researchers found that light with a wavelength of 980 nanometers worked best. Using this system, the researchers measured changes in the height of red blood cells, with nanoscale sensitivity, through a silicon wafer similar to those used in most electronics labs. As red blood cells flow through the body, they often have to squeeze through very narrow vessels. When these cells are infected with malaria, they lose this ability to deform, and form clogs in tiny vessels. The new microscopy technique could help scientists study how this happens, Dingari says; it could also be used to study the dynamics of the malformed blood cells that cause sickle cell anemia. The researchers also used their new system to monitor human embryonic kidney cells as pure water was added to their environment — a shock that forces the cells to absorb water and swell up. The researchers were able to measure how much the cells distended and calculate the change in their index of refraction. “Nobody has shown this kind of microscopy of cellular structures before through a silicon substrate,” Mohanty says. “This is an exciting new direction that is likely to open up enormous opportunities for quantitative phase imaging,” says Gabriel Popescu, an associate professor of electrical engineering and computer science at the University of Illinois at Urbana-Champaign who was not part of the research team. “The possibilities are endless: From micro- and nanofluidic devices to structured substrates, the devices could target applications ranging from molecular sensing to whole-cell characterization and drug screening in cell populations,” Popescu says. Mohanty’s lab at UTA is now using the system to study how neurons grown on a silicon wafer communicate with each other. In the Scientific Reports paper, the researchers used silicon wafers that were about 150 to 200 microns thick, but they have since shown that thicker silicon can be used if the wavelength of light is increased into the infrared range. The researchers are also working on modifying the system so that it can image in three dimensions, similar to a CT scan. The research was funded by the National Institute of Biomedical Imaging and Bioengineering and Nanoscope Technologies, LLC.

News Article
Site: http://www.washingtonpost.com/news/energy-environment

This story has been updated. It’s just the latest sign of mounting tension over the next stage of development in the threatened Amazon — enormous dams that will generate huge amounts of electricity, but also, inevitably, have major ecological consequences. A report released Wednesday by Greenpeace — which is highly active in the Amazon region — has decried the Brazilian government’s plans for a huge new hydropower project in the Amazon’s Tapajós river basin, questioning both the project’s purported environmental impact and even its legality. The organization has called for the halting of the project and urges the expansion of other clean energy forms instead. But in reality, other experts said, Brazil’s hunger for energy and major reliance on dams (rather than fossil fuels) for generating it seems unlikely to abate any time soon. The new project, known as the São Luiz do Tapajós dam, is shooting for a maximum electricity generating capacity of more than 8,000 megawatts and, at nearly five miles wide, would block one of the last major unobstructed tributaries in the Amazon and flood thousands of square miles in the process. It’s the largest of five dams currently planned for the Tapajós river, according to Greenpeace, and one of about 200 proposed hydropower projects proposed throughout the Amazon basin. Hydropower is particularly favored by Brazil, where hydroelectric plants account for about 80 percent of the electricity generated in the country. But while hydropower is certainly a low carbon form of energy, scientists and activists are growing increasingly concerned about its other environmental impacts. Recent research has suggested that damming is responsible for a myriad of detrimental effects in the Amazon basin, threatening water quality, degrading habitat for wildlife and drawing more humans into remote regions, which can indirectly drive activities like mining and deforestation. This is a major problem both for the natural environment and for the indigenous populations who live in the affected areas. In this context, Greenpeace charges that the environmental impact assessment submitted by one of the consortia expected to bid for the project was “deeply flawed.” Representatives from Eletrobras, a state-run energy utility company and leader of the consortium that submitted the environmental impact assessment, did not immediately respond to requests for comment on the report. A statement from Brazil’s Ministry of Mines and Energy to The Washington Post in response to the Greenpeace report said, “The current Brazilian hydroelectric projects are characterized by the respect for the environment and the population, with previously defined plans for environmental and social compensation, improvements to the local society, and a commitment to international protocols to be followed in relation with society, as in the Equator Principles.” The statement also noted that hydropower is the cheapest energy source available in Brazil. Even beyond the importance of scientifically sound environmental impact assessments for individual projects, though, other experts have also emphasized the need for basin-wide evaluations of the effects of damming. David McGrath, deputy director and senior scientist at the Earth Innovation Institute and a professor at the Federal University of Pará in Brazil, has previously told The Washington Post that this type of large-scale analysis should be one of the highest priorities for scientists and policymakers looking for a more complete view of how all the hydropower projects in the basin may build on one another’s impacts — although he’s also noted that the institutional capacity for such an analysis is still lacking. While damming is widely believed to be a source of havoc in the natural environment, some experts have also pointed out that environmental destruction can feed back and negatively impact hydropower production. This is a point that was not fully conveyed in the Greenpeace paper, said Claudia Stickler, a scientist and Amazon expert with the Earth Innovation Institute, who was not involved with the report. “The bigger deforestation problem in the Amazon as a whole is really also going to affect these hydropower projects,” Stickler said. “For me, that’s one of the most damning pieces of evidence against a lot of these big installations.” Large-scale deforestation in the Amazon can cause trouble with water flow, Stickler explained. With fewer trees in the region to recycle water and return it to the atmosphere, rainfall patterns can actually be disrupted over time. And the landscape changes that come with deforestation can also cause more water to run off instead of soaking into the soil and being sucked up by the remaining vegetation, making the problem even worse. These factors may disrupt water flow in the Amazon’s river systems over time and lower the output of hydropower installations. “That’s something that’s not being taken into account by the engineers that are continually doing projections of hydropower energy generation,” Stickler said. At the same time, the Greenpeace report argues, dams can become an indirect driver of deforestation in the region as well, by drawing workers into remote areas and leading into the construction of new roads and communities. However, all of these complaints having been made, the solutions to the hydropower issue are still unclear. The Greenpeace report has called on the Brazilian government to halt the Tapajós project, as well as plans for other installations throughout the Amazon, and explore alternative energy sources instead. But this may be an unlikely outcome for the time being. “We’re talking about a giant country that really does mostly depend on hydropower production for its energy,” Stickler said. “As much as Greenpeace might not like the idea that they have economic plans that require more energy, the reality is that you’re not going to be able to do away with that.” In regard to alternative energy solutions, Stickler noted that Brazil’s challenges are similar to those faced in much of the rest of the world — mainly issues with efficiency and storage that, while improving, still need more independent analysis in order to evaluate how well they could take over the power that’s currently being counted on from proposed hydroelectric installations. Even so, Stickler and other scientists have noted that the need for alternative solutions is growing greater as the devastating impacts of damming become increasingly clear. And while the São Luiz do Tapajós project will likely continue on for now, it may also become the next symbol of how profoundly human activity is changing the Amazon.

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