Revolutionary solar cells double as lasers

Latest research finds that the trailblazing ‘perovskite’ material used in solar cells can double up as a laser, strongly suggesting the astonishing efficiency levels already achieved in these cells is only part of the journey.Commercial silicon-based solar cells — such as those seen on the roofs of houses across the country — operate at about 20% efficiency for converting the Sun’s rays into electrical energy. It’s taken over 20 years to achieve that rate of efficiency.A relatively new type of solar cell based on a perovskite material — named for scientist Lev Perovski, who first discovered materials with this structure in the Ural Mountains in the 19th century — was recently pioneered by an Oxford research team led by Professor Henry Snaith.Perovskite solar cells, the source of huge excitement in the research community, already lie just a fraction behind commercial silicon, having reached a remarkable 17% efficiency after a mere two years of research — transforming prospects for cheap large-area solar energy generation.Now, researchers from Professor Sir Richard Friend’s group at Cambridge’s Cavendish Laboratory — working with Snaith’s Oxford group — have demonstrated that perovskite cells excel not just at absorbing light but also at emitting it. The new findings, recently published online in the Journal of Physical Chemistry Letters, show that these ‘wonder cells’ can also produce cheap lasers.By sandwiching a thin layer of the lead halide perovskite between two mirrors, the team produced an optically driven laser which proves these cells “show very efficient luminescence” — with up to 70% of absorbed light re-emitted.The researchers point to the fundamental relationship, first established by Shockley and Queisser in 1961, between the generation of electrical charges following light absorption and the process of ‘recombination’ of these charges to emit light.Essentially, if a material is good at converting light to electricity, then it will be good at converting electricity to light. The lasing properties in these materials raise expectations for even higher solar cell efficiencies, say the Oxbridge team, which — given that perovskite cells are about to overtake commercial cells in terms of efficiency after just two years of development — is a thrilling prospect.”This first demonstration of lasing in these cheap solution-processed semiconductors opens up a range of new applications,” said lead author Dr Felix Deschler of the Cavendish Laboratory. “Our findings demonstrate potential uses for this material in telecommunications and for light emitting devices.”Most commercial solar cell materials need expensive processing to achieve a very low level of impurities before they show good luminescence and performance. Surprisingly these new materials work well even when very simply prepared as thin films using cheap scalable solution processing.The researchers found that upon light absorption in the perovskite two charges (electron and hole) are formed very quickly — within 1 picosecond — but then take anywhere up to a few microseconds to recombine. This is long enough for chemical defects to have ceased the light emission in most other semiconductors, such as silicon or gallium arsenide. “These long carrier lifetimes together with exceptionally high luminescence are unprecedented in such simply prepared inorganic semiconductors,” said Dr Sam Stranks, co-author from the Oxford University team.”We were surprised to find such high luminescence efficiency in such easily prepared materials. This has great implications for improvements in solar cell efficiency,” said Michael Price, co-author from the group in Cambridge.Added Snaith: “This luminescent behaviour is an excellent test for solar cell performance — poorer luminescence (as in amorphous silicon solar cells) reduces both the quantum efficiency (current collected) and also the cell voltage.”Scientists say that this new paper sets expectations for yet higher solar cell performance from this class of perovskite semiconductors. Solar cells are being scaled up for commercial deployment by the Oxford spin-out, Oxford PV Ltd. …

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Cereal flake size influences calorie intake

People eat more breakfast cereal, by weight, when flake size is reduced, according to Penn State researchers, who showed that when flakes are reduced by crushing, people pour a smaller volume of cereal into their bowls, but still take a greater amount by weight and calories.”People have a really hard time judging appropriate portions,” said Barbara Rolls, professor of nutritional sciences and Helen A. Guthrie Chair in Nutrition. “On top of that you have these huge variations in volume that are due to the physical characteristics of foods, such as the size of individual pieces, aeration and how things pile up in a bowl. That adds another dimension to the difficulty of knowing how much to take and eat.”According to Rolls, national dietary guidelines define recommended amounts of most food groups in terms of measures of volume such as cups.”This can be a problem because, for most foods, the recommended amounts have not been adjusted for variations in physical properties that affect volume, such as aeration, cooking, and the size and shape of individual pieces.” Rolls said. “The food weight and energy required to fill a given volume can vary, and this variation in the energy content of recommended amounts could be a challenge to the maintenance of energy balance.”The researchers tested the influence of food volume on calorie intake by systematically reducing the flake size of a breakfast cereal with a rolling pin so that the cereal was more compact and the same weight filled a smaller volume. In a crossover design, the team recruited 41 adults to eat cereal for breakfast once a week for four weeks. The cereal was either standard wheat flakes or the same cereal crushed to reduce the volume to 80 percent, 60 percent or 40 percent of the standard. The researchers provided a constant weight of cereal in an opaque container and participants poured the amount they wanted into a bowl, added fat-free milk and non-calorie sweetener as desired and consumed as much as they wanted.The researchers reported their results in the current issue of the Journal of the Academy of Nutrition and Dietetics.The research showed that as flake size was reduced, subjects poured a smaller volume of cereal, but still took a significantly greater amount by weight and energy content. Despite these differences, subjects estimated that they had taken a similar number of calories of all versions of the cereal. They ate most of the cereal they took, so as flake size was reduced, breakfast energy intake increased.”When faced with decreasing volumes of cereal, the people took less cereal,” Rolls said. …

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When mothers are active so are their children — but many mothers are not

Parents are strong influences in the lives of young children, with patterns of behaviour established in the early years laying the foundation for future choices. A new study suggests that, when it comes to levels of physical activity, it is mothers who set (or don’t set) the pace.An analysis of the physical activity levels of more than 500 mothers and pre-schoolers, assessed using activity monitors to produce accurate data, found that the amount of activity that a mother and her child did each day was closely related. Overall, maternal activity levels were strikingly low: only 53% of mothers engaged in 30 minutes of moderate-to-vigorous physical activity at least once a week. The UK Government recommends achieving 150 minutes of at least ‘moderate intensity physical activity’ (such as brisk walking) over the week as one of the ways of achieving its physical activity guidelines.The results of the study are published in the journal Pediatrics on 24 March 2014. The paper ‘Activity Levels in Mothers and Their Preschool Children’ suggests that, given the link between mothers and young children, policies to improve children’s health should be directed to whole families and seek to engage mothers in particular.The research was overseen by Dr Esther van Sluijs at the MRC Epidemiology Unit and the Centre for Diet and Activity Research, University of Cambridge, and led by Kathryn Hesketh (formerly of Cambridge and now UCL), in collaboration with researchers at the MRC Lifecourse Epidemiology Unit, University of Southampton.The study is the first to show a direct association in a large sample of mothers and children, both fitted with activity monitors at the same time. It shows that young children are not ‘just naturally active’ and that parents have an important role to play in the development of healthy activity habits early on in life. The research also provides important evidence for policy makers to inform programmes that promote physical activity in families with young children. Its findings suggest that all family members can benefit from such efforts.It is well established that physical activity is closely linked to health and disease prevention. Research shows that active mothers appear to have active school-aged children, who are in turn more likely than their less active peers to have good health outcomes. However, there has been little large-scale research into the association between the activity of mothers and that of preschool-aged children or about the demographic and temporal factors that influence activity levels in mothers of young children.The research published in the Pediatrics paper drew on data obtained from 554 women and their four-year-old children who are participants in the Southampton Women’s Survey, devised and run by the MRC Lifecourse Epidemiology Unit. …

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Program taught in American Sign Language helps deaf achieve healthier weight

A group of deaf adults using American Sign Language in a healthy lifestyle program successfully lost weight, according to a study presented Wednesday.In the first randomized trial of lifestyle modification or weight reduction with deaf people using American Sign Language, participants had moderate improvements in their weight and level of physical activity after a 16-week program.”Existing mainstream programs focused on weight and weight-related behaviors are often inaccessible to the deaf community,” said Steven Barnett, M.D., lead author of the study and associate professor of family medicine and public health sciences at the University of Rochester in New York. “Collaboration with deaf ASL users is essential to develop accessible and culturally appropriate programs.”In partnership with the deaf community in Rochester, the researchers adapted a healthy lifestyle program shown to be effective in hearing people.A previous study, using accessible public health surveillance in Rochester, found that obesity (body mass index or BMI > 30) is more prevalent in the local deaf community than in the general population — slightly more than 34 percent of the deaf people were obese, compared to nearly 27 percent in the general population.In the Deaf Weight Wise trial, 104 overweight or obese participants were either enrolled in the healthy lifestyle program, with weekly 2-hour group sessions, or assigned to a delayed group who would receive the intervention later.For the group sessions, counselors used motivational interviewing techniques to encourage lifestyle change and help participants develop strategies to maintain healthy eating, such as in social situations and during stress. They were encouraged to exercise at least 150 minutes per week.After six months, participants in the intervention group had lost 7.4 pounds more and reduced their BMI 1.35 points more than the delayed group. Most of the intervention group’s participants (58.3 percent) lost at least 5 percent of their baseline weight, compared with 14.3 percent of the delayed group.Researchers will continue to follow participants for 24 months.”During program development and during the trial, deaf community members emphasized the importance of having deaf counselors,” said Barnett, who directs the Rochester Prevention Research Center: National Center for Deaf Health Research. “I realize this is not possible to implement everywhere at present. We are working on program adaptations to address access to counselors who are deaf ASL users.”Lori DeWindt, M.A., a member of the Deaf Weight Wise Study Group and a Deaf Weight Wise counselor, said, “Participants were comfortable in the culturally affirming environment in which everyone signs. This setting, along with accessible information and peer support, contributed to the positive experience of participants.”Co-authors are Erika Sutter, M.P.H., Thomas Pearson, M.D., M.P.H., Ph.D., and members of the Deaf Weight Wise Study Group. Disclosures are listed on the abstract.The Centers for Disease Control and Prevention Research Centers Program funded the study. It was presented at the American Heart Association’s Epidemiology & Prevention/Nutrition, Physical Activity & Metabolism Scientific Sessions 2014.Story Source:The above story is based on materials provided by American Heart Association. Note: Materials may be edited for content and length.

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Mindfulness-based meditation helps teenagers with cancer

Mindfulness-based meditation could lessen some symptoms associated with cancer in teens, according to the results of a clinical trial intervention led by researchers at the University of Montreal and its affiliated CHU Sainte-Justine children’s hospital.Mindfulness-based meditation focuses on the present moment and the connection between the mind and body. Adolescents living with cancer face not only the physical symptoms of their condition, but also the anxiety and uncertainty related to the progression of the disease, the anticipation of physical and emotional pain related to illness and treatment, the significant changes implied in living with cancer, as well as the fear of recurrence after remission. Catherine Malboeuf-Hurtubise of the university’s Department of Psychology presented the findings today at the American Psychosomatic Society Meeting in San Francisco.The researchers asked 13 adolescents with cancer to complete questionnaires covering mood (positive and negative emotions, anxiety and depression), sleep and quality of life. The group was divided in two: a first group of eight adolescents were offered eight mindfulness-based meditation sessions and the remaining five adolescents in the control group were put on a wait-list. The eight sessions were 90 minutes long and took place weekly. After the last meditation session, patients from both groups filled out the same questionnaires a second time. “We analyzed differences in mood, sleep and quality of life scores for each participant and then between each group to evaluate if mindfulness sessions had a greater impact than the simple passage of time. We found that teenagers that participated in the mindfulness group had lower scores in depression after our 8 sessions. Girls from the mindfulness group reported sleeping better. We also noticed that they developed mindfulness skills to a greater extent than boys during the sessions,” Malboeuf-Hurtubise said. …

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Obese adolescents not getting enough sleep?

Lack of sleep and obesity have been associated with an increased risk of cardiovascular and metabolic diseases in adults and young children. However, the association is not as clear in adolescents, an age group that is known to lack adequate sleep and have an overweight and obesity prevalence rate of 30% in the US. In a new study scheduled for publication in The Journal of Pediatrics, researchers found that cardiometabolic risk in obese adolescents may be predicted by typical sleep patterns.Heidi B. IglayReger, PhD, and colleagues from the University of Michigan and Baylor University studied 37 obese adolescents (11-17 years of age). Metabolic syndrome characteristics (fasting cholesterol and blood sugar, waist circumference, body mass index [BMI], and blood pressure) were measured to create a continuous cardiometabolic risk score. The adolescents were fitted with a physical activity monitor, which was worn 24 hours a day for seven days, to measure typical patterns of physical activity and sleep.One-third of the participants met the minimum recommendation of being physically active at least 60 minutes a day. Most participants slept approximately seven hours each night, usually waking up at least once. Only five of the participants met the minimal recommended 8.5 hours of sleep per night. Even after controlling for factors that may impact cardiometabolic risk, like BMI and physical activity, low levels of sleep remained a significant predictor of cardiometabolic risk in obese teens. This shows that even among those already considered to be at risk for cardiometabolic disease, in this case obese teens’ decreased sleep duration was predictive of increased cardiometabolic risk.This study cannot determine whether lack of sleep causes cardiometabolic disease or if obesity itself causes sleep disturbances. …

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Brain differences linked to insomnia identified by researchers

Johns Hopkins researchers report that people with chronic insomnia show more plasticity and activity than good sleepers in the part of the brain that controls movement.”Insomnia is not a nighttime disorder,” says study leader Rachel E. Salas, M.D., an assistant professor of neurology at the Johns Hopkins University School of Medicine. “It’s a 24-hour brain condition, like a light switch that is always on. Our research adds information about differences in the brain associated with it.”Salas and her team, reporting in the March issue of the journal Sleep, found that the motor cortex in those with chronic insomnia was more adaptable to change — more plastic — than in a group of good sleepers. They also found more “excitability” among neurons in the same region of the brain among those with chronic insomnia, adding evidence to the notion that insomniacs are in a constant state of heightened information processing that may interfere with sleep.Researchers say they hope their study opens the door to better diagnosis and treatment of the most common and often intractable sleep disorder that affects an estimated 15 percent of the United States population.To conduct the study, Salas and her colleagues from the Department of Psychiatry and Behavioral Sciences and the Department of Physical Medicine and Rehabilitation used transcranial magnetic stimulation (TMS), which painlessly and noninvasively delivers electromagnetic currents to precise locations in the brain and can temporarily and safely disrupt the function of the targeted area. TMS is approved by the U.S. Food and Drug Administration to treat some patients with depression by stimulating nerve cells in the region of the brain involved in mood control.The study included 28 adult participants — 18 who suffered from insomnia for a year or more and 10 considered good sleepers with no reports of trouble sleeping. Each participant was outfitted with electrodes on their dominant thumb as well as an accelerometer to measure the speed and direction of the thumb.The researchers then gave each subject 65 electrical pulses using TMS, stimulating areas of the motor cortex and watching for involuntary thumb movements linked to the stimulation. Subsequently, the researchers trained each participant for 30 minutes, teaching them to move their thumb in the opposite direction of the original involuntary movement. They then introduced the electrical pulses once again.The idea was to measure the extent to which participants’ brains could learn to move their thumbs involuntarily in the newly trained direction. …

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The pain of social exclusion: Physical pain brain circuits activated by ‘social pain’

The distress caused by social stimuli (e.g., losing a friend, experiencing an injustice or more in general when a social bond is threatened) activates brain circuits related to physical pain: as observed in a study conducted by SISSA, this also applies when we experience this type of pain vicariously as an empathic response (when we see somebody else experiencing it).We would like to do without pain and yet without it we wouldn’t be able to survive. Pain signals dangerous stimuli (internal or external) and guides our behaviour. Its ultimate goal is to prioritize escape, recovery and healing. That’s why we feel it and why we’re also good at detecting it in others. Pain in fact protects not only the individual but also his social bonds. The brain contains circuits related to the more physical aspects of pain and others related to affective aspects. As observed in a study just published by Giorgia Silani, Giovanni Novembre and Marco Zanon of the International School for Advanced Studies (SISSA) of Trieste, social pain activates some brain circuits of physical pain whether we feel it personally or when we experience it vicariously as an empathic response to other people’s pain.The study by Silani and colleagues is innovative since it adopted a more realistic experimental procedure than used in the past and compared behaviours and the results of functional magnetic resonance imaging in the same subjects, during tests involving both physical and social pain. “Classic experiments used a stylized procedure in which social exclusion situations were simulated by cartoons. We suspected that this simplification was excessive and likely to lead to systematic biases in data collection, so we used real people in videos.”The subjects took part in the experimental sessions simulating a ball tossing game, where one of the players was deliberately excluded by the others (condition of social pain). The player could be the subject herself or her assigned confederate. …

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Team sport compensates for estrogen loss

When women enter menopause, their estrogen levels taper. This increases their risk of cardiovascular disease. New research from University of Copenhagen shows that interval-based team sport can make up for this estrogen loss as it improves their conditions, reduces blood pressure and thereby protects the cardiovascular system.While aging and an array of physical transformations go hand in hand for all, menopause has a significant influence on physical changes in women.Estrogen, the primary female sex hormone, is an important guardian of the female vascular system. Thus, as estrogen levels fall during menopause, the risks of increased blood pressure and development of cardiovascular disease increases.A new study by the University of Copenhagen’s Centre for Team Sport and Health documents and addresses the issue.Changes to the cardiovascular system occur soon after menopause”Results demonstrate that blood pressure among post-menopausal women is 10% higher immediately after menopause than in similarly-aged, pre-menopausal women. They also had higher levels of an early marker for arteriosclerosis,” explains postdoc Michael Nyberg.The new aspect of this study is that researchers have investigated the effects of estrogen in women of the same age, both before and after menopause. Previous studies didn’t look at similarly aged pre- and post-menopausal women. Instead, they investigated women with 15-20 year gaps in age. Therefore, they were unable to determine whether changes were due to age or estrogen loss.Results of the recent study have now been published in the journal, The American Journal of Physiology.Floorball prevents cardiovascular disease among womenIn a bid to prevent increased risk of cardiovascular disease, the study examined the effect of 12-week floorball training among post-menopausal women. The results were clear.”Following just 12 weeks of twice weekly practices, the women’s conditions had improved and their blood pressure was reduced by 4 mmHg, which correlates with a 40% lower risk of stroke,” explains Professor and Centre Director Jens Bangsbo.Continuing, Bangsbo asserts that, “Furthermore, there was a positive development in relation to levels of substances vital to blood vessel function, including a 20% decrease in markers associated with arteriosclerosis.””The results demonstrate that team sports that include interval exercise are a fantastic opportunity for hormone treatment, in relation to estrogen, because one can avoid an array of undesirable side-effects,” according to postdoc, Michael Nyberg.Team sport — fun as well as healthy”Another advantage of a team sport like floorball is that participants have fun. That’s important, because when a person is engaged in a team sport, they aren’t preoccupied with the otherwise intense exercise in which they are engaged. …

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Dangers of … sitting? Regardless of exercise, too much sedentary time is linked to major disability after 60

If you’re 60 and older, every additional hour a day you spend sitting is linked to doubling the risk of being disabled — regardless of how much moderate exercise you get, reports a new Northwestern Medicine study.The study is the first to show sedentary behavior is its own risk factor for disability, separate from lack of moderate vigorous physical activity. In fact, sedentary behavior is almost as strong a risk factor for disability as lack of moderate exercise.If there are two 65-year-old women, one sedentary for 12 hours a day and another sedentary for 13 hours a day, the second one is 50 percent more likely to be disabled, the study found.”This is the first time we’ve shown sedentary behavior was related to increased disability regardless of the amount of moderate exercise,” said Dorothy Dunlop, professor of medicine at Northwestern University Feinberg School of Medicine and lead author of the study. “Being sedentary is not just a synonym for inadequate physical activity.”Disability affects more than 56 million Americans. It’s defined by limitations in being able to do basic activities such as eating, dressing or bathing oneself, getting in and out of bed and walking across a room. Disability increases the risk of hospitalization and institutionalization and is a leading source of health care costs, accounting for $1 in $4 spent.The study will be published February 19 in the Journal of Physical Activity & Health.The finding — that being sedentary was almost as strong a risk factor for disability as lack of moderate vigorous activity — surprised Dunlop.”It means older adults need to reduce the amount of time they spend sitting, whether in front of the TV or at the computer, regardless of their participation in moderate or vigorous activity,” she said.The study focused on a sample of 2,286 adults aged 60 and older from the National Health and Nutrition Examination Survey. It compared people in similar health with the same amount of moderate vigorous activity. Moderate activity is walking briskly, as if you are late to an appointment.The participants wore accelerometers from 2002 to 2005 to measure their sedentary time and moderate vigorous physical activity. The accelerometer monitoring is significant because it is objective. The older and heavier people are, the more they tend to overestimate their physical activity. Previous research indicated a relationship between sedentary behavior and disability but it was based on self-reports and, thus, couldn’t be verified.Because the study examines data at one point in time, it doesn’t definitively determine sedentary behavior causes disability. …

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Research examines acupuncture needle quality

The quality of needles used in acupuncture worldwide is high but needs to be universally improved to increase safety and avoid potential problems such as pain and allergic reactions, RMIT University researchers have found.The researchers looked at surface conditions and other physical properties of the two most commonly used stainless steel acupuncture needle brands.The study, published in Acupuncture in Medicine, found that although manufacturing processes have improved, surface irregularities and bent needle tips have not been entirely eliminated.Lead investigator Professor Mike Xie, Director of the Centre for Innovative Structures and Materials at RMIT, said acupuncture was a safe treatment overall but the research showed it could be made even safer.”In China, Chinese medicine including acupuncture, accounts for 40 per cent of all medical treatment, while in Western countries, acupuncture is one of the most frequently used complementary therapies,” he said.”Our findings show that acupuncture needle manufacturers should review and improve their quality control procedures for the fabrication of needles.”In particular, needle tips should be properly formed, sharpened and cleansed.”Extensive research on acupuncture has demonstrated its safety and benefit for a range of conditions. But more needs to be done to enhance the comfort and safety of patients undergoing acupuncture treatment worldwide.”China, Japan and Korea are the main suppliers of acupuncture needles, with China providing up to 90 per cent of the world’s acupuncture needles.In the study, scanning electron microscope images were taken of 10 randomly chosen needles from each brand, with further images taken after each needle underwent a standard manipulation — the equivalent of using them on human tissue — with an acupuncture needling practice gel.The images revealed significant surface irregularities and inconsistencies at the needle tips, particularly in needles from one of the brands.Metallic lumps and small, loosely attached pieces of material were observed on the surfaces of some needles. Some of these fragments disappeared after the acupuncture manipulation.Co-author Professor Charlie Xue, Director of the Traditional and Complementary Medicine Research Program in the Health Innovations Research Institute and Head of the School of Health Sciences at RMIT, said the metallic residue could be deposited in human tissues, causing discomfort and potentially allergic reactions such as dermatitis.”While acupuncture needle induced dermatitis has been extremely rare, it is important to minimise the potential for such reaction through further improvement of the needles used in human practice,” Professor Xue said.”Malformed needle tips can cause problems including bleeding, bruising, or strong pain during needling, which are more commonly reported following acupuncture treatment.”An off-centre needle tip could result in the needle altering its direction during insertion and manipulation, consequently damaging adjacent tissues.”While none of these potential problems would result in serious or long-term injury, patient experience and safety are paramount and the quality of acupuncture needles must be more rigorously improved.”The researchers suggested the small metallic pieces found on the needle surfaces were most likely from the grinding and polishing processes during the manufacture of the needles. These processes would also generate electrostatic forces that would attract tiny metal filings to the needle surfaces. The metallic pieces should have been removed from the needles if adequate cleansing processes had been carried out, the study found.Story Source:The above story is based on materials provided by RMIT University. Note: Materials may be edited for content and length.

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Superconductivity in orbit: Scientists find new path to loss-free electricity

Brookhaven Lab researchers captured the distribution of multiple orbital electrons to help explain the emergence of superconductivity in iron-based materials. Armed with just the right atomic arrangements, superconductors allow electricity to flow without loss and radically enhance energy generation, delivery, and storage. Scientists tweak these superconductor recipes by swapping out elements or manipulating the valence electrons in an atom’s outermost orbital shell to strike the perfect conductive balance. Most high-temperature superconductors contain atoms with only one orbital impacting performance — but what about mixing those elements with more complex configurations?Now, researchers at the U.S. Department of Energy’s Brookhaven National Laboratory have combined atoms with multiple orbitals and precisely pinned down their electron distributions. Using advanced electron diffraction techniques, the scientists discovered that orbital fluctuations in iron-based compounds induce strongly coupled polarizations that can enhance electron pairing — the essential mechanism behind superconductivity. The study, set to publish soon in the journal Physical Review Letters, provides a breakthrough method for exploring and improving superconductivity in a wide range of new materials.While the effect of doping the multi-orbital barium iron arsenic — customizing its crucial outer electron count by adding cobalt — mirrors the emergence of high-temperature superconductivity in simpler systems, the mechanism itself may be entirely different.”Now superconductor theory can incorporate proof of strong coupling between iron and arsenic in these dense electron cloud interactions,” said Brookhaven Lab physicist and study coauthor Weiguo Yin. “This unexpected discovery brings together both orbital fluctuation theory and the 50-year-old ‘excitonic’ theory for high-temperature superconductivity, opening a new frontier for condensed matter physics.”Atomic Jungle GymImagine a child playing inside a jungle gym, weaving through holes in the multicolored metal matrix in much the same way that electricity flows through materials. This particular kid happens to be wearing a powerful magnetic belt that repels the metal bars as she climbs. This causes the jungle gym’s grid-like structure to transform into an open tunnel, allowing the child to slide along effortlessly. …

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Proteins snap those wrinkly fingers back into shape: Physicists model skin from wet to dry

You know how your fingers wrinkle up in the bath? The outer layer of your skin absorbs water and swells up, forming ridges — but quickly returns to its old state when dry. Two physicists, Professor Roland Roth of Tbingen University and Dr. Myfanwy Evans at Erlangen University have shown just why skin has this remarkable ability. Their conclusions were published recently in the journal Physical Review Letters.The swelling and absorption of water occur in the outermost skin layer, which is made of dead cells that are stacked in layers like bricks. These cells are filled with a network of filaments made of the protein keratin. These keratin strands interlock to form a three-dimensional lattice — which can increase its volume by five times when the strands stretch out.Evans and Roth have shown how the structure could help skin cells swell and shrink. They developed a model describing how the system’s energy varies as the network’s spacing changes. The researchers first calculated the filaments’ willingness to absorb water and found that this energy decreases, meaning that the structure is inclined to expand and absorb water.But they thought some other force must act to reverse the system’s expansion, since the process reverses easily in real cells. Inspired by previous filament elasticity measurements, they realized that the tension in a stretched filament could provide the counteracting force. …

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Feeling powerless increases the weight of the world… literally

New research shows that the more personally and socially powerless you feel the heavier objects appear to weigh.Scientists have found that people who feel powerless actually see the world differently, and find a task to be more physically challenging than those with a greater sense of personal and social power.Eun Hee Lee — a researcher working with Dr Simone Schnall at Cambridge’s Department of Psychology — carried out a series of tests in which volunteers were surreptitiously surveyed about their own social power, then asked to lift boxes of varying weights and guess how heavy they were. Those who felt powerless consistently perceived the weight of the boxes as much heavier than those who felt more powerful.The study is the first demonstration that power — a ‘psychosocial’ construct relating to the control of resources — changes peoples’ perception of objects; that how you feel about your social standing in a situation can influence how you see the physical environment.The researchers say this overestimation of weight may be an adaptive strategy when faced with a lack of resources: when in a position of powerlessness, it would be ‘advantageous’ to have an overly cautious approach to the world in order to preserve your existing limited resources.Experiencing perceptual attributes of the world — such as the weight of objects — in an “exaggerated fashion” when feeling powerless might be symptomatic of this instinctive resource conservation.The study is published this week in the Journal of Experimental Psychology.”Although many psychological studies have been conducted on power not much was known about how power influences actual perceptual experiences in everyday life,” said lead researcher Eun Hee Lee.”This research demonstrates that people’s social role, as indicated by a sense of social power, or a lack therefore, can change the way they see the physical environment.”To measure a person’s sense of their own social power, Lee and Schnall conducted three separate studies — all disguised by cover stories so that participants were unaware of what was being tested.In the first, 145 participants were asked to rank how strongly they felt a series of statements applied to them — such as “I can get people to listen to what I say” — to measure beliefs about their power in social relationships. They were then tasked with lifting a number of boxes and guessing the weight, before taking a final test to gauge their mood. Researchers found that the lower a person’s feelings of social power, the more they thought the boxes weighed.In the second test, the researchers manipulated the sense of power by asking 41 participants to sit in either an expansive, domineering position — with one elbow on the arm of their chair and the other on the desk next to them — or a more constricting one, with hands tucked under thighs and shoulders dropped.Prior to manipulation, most participants overestimated the weight; after manipulation, those who sat in the more powerful pose gave more accurate estimates, while those in the submissive condition continued to imagine heavier weight.In the final test, 68 participants were asked to recall an experience in which they had felt either powerful or powerless, and then repeatedly estimate the weights of various boxes — under the guise of studying the effect of exercise on autobiographical memory. Those who focused on the powerful incident became more accurate at guessing the weight, while those recalling a powerless situation continually overestimated the heaviness of the boxes.While previous research has shown that various physical and emotional states can influence perception of the environment — such as perceiving a hill slant to be steeper when wearing a heavy backpack, or threatening objects, such as a tarantula, appearing to be further from your face when feeling good about yourself — this is the first study to show that a sense of power can now be added to that list.Giulio Andreotti, the former Italian Prime Minister who was nicknamed ‘Il Divo’ after the epithet for Julius Caesar, famously once said that “power tires only those who do not have it.” Lee and Schnall write that this comment is “no longer an unsubstantiated conjecture,” and that their data suggests the world of the powerless “is indeed full of heavy burdens.”Added Lee: “Power plays a role when it is present in a given moment, but also when it comes to people’s personality. We find that personality, which determines how people interact with the social world, also shapes how people interact with the physical world.”

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Prototype of single ion heat engine created

Scientists at Johannes Gutenberg University Mainz (JGU) and the University of Erlangen-Nuremberg are working on a heat engine that consists of just a single ion. Such a nano-heat engine could be far more efficient than, for example, a car engine or a coal-fired power plant. A usual heat engine transforms heat into utilizable mechanical energy with the corresponding efficiency of an Otto engine amounting to only about 25 percent, for instance. The proposed nano-heat engine consisting of a single calcium ion would be much more efficient. The main aim of the research being conducted is to better understand how thermodynamics works on very small scales. A pilot prototype of such a single-ion heat engine is currently being constructed at Mainz University.As the physicists explain in an article recently published in the journal Physical Review Letters, the efficiency of heat engines powered by thermal heat reservoirs is determined by the second law of thermodynamics, one of the fundamental concepts in physics. It was as far back as 1824 that Frenchman Nicolas Carnot calculated the maximum possible efficiency limit of such engines, now known as the Carnot limit. In the case of the newly proposed nano-heat engine, the scientists have been theoretically able to exceed the classic Carnot limit by manipulating the heat baths and exploiting nonequlibrium states.Calculations and simulations made about a year ago showed for the first time that the thermo-dynamic flow in an internal combustion engine could be reproduced using individual ions. The idea was to use a calcium 40 ion, which has a diameter a million times smaller than that of a human hair, for this purpose. “Individual ions can basically act as the piston and drive shaft or, in other words, represent the entire engine,” explained Johannes Ronagel of the Quantum, Atomic, and Neutron Physics (QUANTUM) work group of the JGU Institute of Physics. …

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Testosterone not as helpful as expected for some women going through menopause early

With plummeting hormone levels, natural menopause before age 40 can put a damper on women’s mental well being and quality of life. But bringing testosterone back up to normal may not bring them the boost some hoped for, found a new study published online today in Menopause, the journal of The North American Menopause Society (NAMS).Before age 40, ovaries stop functioning in about 1% of women without some obvious genetic abnormality to blame, bringing on an early menopause. Called “primary ovarian insufficiency” or POI, the condition can spell not only infertility and other physical problems but also depression and decreased quality of life. Adding back lost estrogen and progesterone helps. But ovaries normally produce testosterone, too, which has mental and physical effects. Adding it back, some thought, could be helpful.But studies looking at adding testosterone for women who lose ovarian function for other reasons, such as after natural menopause or hysterectomy, haven’t yielded consistent results. So these investigators looked at the mood and quality of life data from women with POI in a study done at the National Institutes of Health Clinical Center in Bethesda, MD, where women underwent a year of hormone therapy that included testosterone. In the randomized, double-blind, placebo controlled study, 61 women used placebo patches and 67 women used patches that delivered 150 micrograms of testosterone a day, similar to the Intrinsa patch that was rejected by FDA as a treatment for low sexual desire in women.After 12 months, testosterone levels were back up to normal for the women who got the treatment. The investigators saw no detrimental effects of testosterone, but they found no significant improvement either in measurements of quality of life, self esteem and mood compared with placebo.Bringing testosterone back to normal doesn’t help these aspects of life, suggesting that it’s something other than testosterone that plays a role in mood problems for women with POI, concluded the researchers.But there are still unknowns. The study didn’t measure depression and sexual function specifically, so the investigators couldn’t draw conclusions about the effects of normalizing testosterone on those problems. …

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Workers Compensation

Despite the best actions of employers and employees, accidents on the job do happen. Whether an employee works behind a desk, drives behind a wheel, or stands behind a counter, things can go wrong and injuries can occur. Regardless of their nature, injuries and illnesses have financial, emotional, and personal costs – including lost wages, lost earning potential, and physical pain and suffering.In the event of a job-related injury, laws are in place to protect workers’ rights. In every state but Texas, almost all employers are required by law to carry workers’ compensation insurance in order to cover medical expenses that result from work-related illnesses and injuries, and to partially replace workers’ lost wages.This mandate incurs a large cost for employers.A report from the National Academy of Social Insurance indicated that in 2007, 131 million U.S. workers were covered by workers’ compensation insurance at a cost of $85 billion dollars to employers. If those numbers seem extreme, consider these numbers from the Bureau of Labor Statistics:Nearly three million cases of non-fatal illness and injury were documented in the private sector in 2011, equal to a rate of 3.5 cases per every 100 full-time workers. A key measure of the severity of injuries and illnesses is the median number of days away from work, which was eight days for 2011, and virtually unchanged from the three previous years. In 2010, nearly 4,700 workers died as a result of injuries sustained while at work – which translates to one worker dying every two hours from a job-related injury. Highway incidents remain the most common cause of fatal occupational injuries, followed by falls, workplace homicides, and being struck by objects. In 2010, the private construction industry experienced the highest number of fatal occupational injuries (774), while the agriculture, forestry, fishing, and hunting industry had the highest fatal work injury rate (27.9 per 100,000 full-time equivalent workers). …

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CONTENT REMOVED

Growing up I was not much of a sporty kid.Sure, I’d tried the buffet strategy, “I’ll try a little bit of this and a little bit of that.”, But I never quite settled on something I enjoyed.After getting concussed during Rugby, I decided that was too rough. I tried playing cricket, but then I realized I didn’t enjoy standing in the sun mostly doing nothing all day. I looked into underwater hockey, but then I realized the boys had to wear speedos and so I vetoed that too. While all my “jock” buddies were out getting abs, tans, and ladies I was in the music room playing punk music. Despite my fingers getting a workout on the guitar fret board, the only physical change …

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Exercise provides some benefits for depression

Sep. 11, 2013 — Exercise may benefit people suffering from depression, according to an updated systematic review published in The Cochrane Library. The authors of the review found evidence to suggest that exercise reduces symptoms of depression, although they say more high quality trials are needed.Worldwide, more than 120 million people suffer from depression. Antidepressants and psychological therapies are recommended as effective treatments for depression. However, antidepressants have side-effects and some people prefer not to receive, or may not have access to, psychological therapies. Physical exercise is also used as a treatment for depression. There are a number of reasons why it might work such as changing hormone levels that affect mood or providing a distraction from negative thoughts.The previous version of the Cochrane review found only limited evidence of benefit for exercise in depression. However, more trials have now been completed, leading researchers to carry out a further update. Altogether, they reviewed the results of 39 trials involving 2,326 people diagnosed with depression. The severity of patients’ symptoms was assessed using standard scales of depression.In 35 trials comparing exercise with control treatments or no treatment, the researchers saw moderate benefits of exercise for treating depression. …

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Aerobic fitness boosts learning, memory in 9-10-year-old children

Sep. 11, 2013 — Physical fitness can boost learning and memory in children, particularly when initial learning on a task is more challenging, according to research published September 11 in the open access journal PLOS ONE by Lauren Raine and colleagues from the University of Illinois at Urbana-Champaign.Share This:Forty-eight children aged nine to ten were asked to memorize names and locations on a fictitious map, either only by studying the information or being tested on the material as they studied. Half the children were in the top 30% of their age group on a test measuring aerobic fitness, while the other half scored in the lowest 30 percent. When asked to recollect the information studied, children who were fitter performed better than those who were not as fit.The difference between the high-fitness and low-fitness groups was also stronger when the initial learning was performed by studying alone than when testing and study were interspersed. Previous studies have suggested that combining testing and study improves later recall in children, and is less challenging than studying alone. Based on these results, the authors suggest that fitness levels may influence learning differently when the study method used is more challenging, and that higher levels of aerobic fitness can benefit learning and memory in school-age children. They conclude, “Future research should focus on the manner in which these factors impact the neural processes of children during learning.”In addition, the study suggests these findings may be important from an educational policy perspective. As the authors state, “Reducing or eliminating physical education in schools, as is often done in tight financial times, may not be the best way to ensure educational success among our young people.”Share this story on Facebook, Twitter, and Google:Other social bookmarking and sharing tools:|Story Source: The above story is based on materials provided by Public Library of Science. Note: Materials may be edited for content and length. For further information, please contact the source cited above. …

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