Breakthrough in creating invisibility cloaks, stealth technology

Controlling and bending light around an object so it appears invisible to the naked eye is the theory behind fictional invisibility cloaks.It may seem easy in Hollywood movies, but is hard to create in real life because no material in nature has the properties necessary to bend light in such a way. Scientists have managed to create artificial nanostructures that can do the job, called metamaterials. But the challenge has been making enough of the material to turn science fiction into a practical reality.The work of Debashis Chanda at the University of Central Florida, however, may have just cracked that barrier. The cover story in the March edition of the journal Advanced Optical Materials, explains how Chanda and fellow optical and nanotech experts were able to develop a larger swath of multilayer 3-D metamaterial operating in the visible spectral range. They accomplished this feat by using nanotransfer printing, which can potentially be engineered to modify surrounding refractive index needed for controlling propagation of light.”Such large-area fabrication of metamaterials following a simple printing technique will enable realization of novel devices based on engineered optical responses at the nanoscale,” said Chanda, an assistant professor at UCF.The nanotransfer printing technique creates metal/dielectric composite films, which are stacked together in a 3-D architecture with nanoscale patterns for operation in the visible spectral range. Control of electromagnetic resonances over the 3-D space by structural manipulation allows precise control over propagation of light. Following this technique, larger pieces of this special material can be created, which were previously limited to micron-scale size.By improving the technique, the team hopes to be able to create larger pieces of the material with engineered optical properties, which would make it practical to produce for real-life device applications. For example, the team could develop large-area metamaterial absorbers, which would enable fighter jets to remain invisible from detection systems.Story Source:The above story is based on materials provided by University of Central Florida. Note: Materials may be edited for content and length.

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Playing as black: Avatar race affects white video game players

What happens when white video game players see themselves as black characters in a violent game?A new study suggests some disturbing answers: It makes the white players act more aggressively after the game is over, have stronger explicit negative attitudes toward blacks and display stronger implicit attitudes linking blacks to weapons.These results are the first to link avatar race in violent video games to later aggression, said Brad Bushman, co-author of the study and professor of communication and psychology at The Ohio State University.And it raises another troubling impact that violent video games can have on players, he said.”Playing a violent video game as a black character reinforces harmful stereotypes that blacks are violent,” Bushman said.”We found there are real consequences to having these stereotypes — it can lead to more aggressive behavior.”The results appear online in the journal Social Psychological and Personality Science and will be published in a future print edition.The study involved two related experiments. In the first, 126 white university students (60 percent males) played the violent game Saints Row 2. They were randomly assigned to play the game either as a black or white male avatar.Before the participants arrived, the researchers set up the game with the black or white avatar and rotated the game view so that the avatar was visible to the participant when he or she started playing.The participants were assigned to play with a violent goal (break out of prison) or a nonviolent goal (find a chapel somewhere in the city without harming others).Afterward, those who played with the violent goal and as a black avatar showed stronger explicit negative attitudes toward blacks than did those who played as a white avatar. For example, those who played as a black avatar were more likely to agree with the statement “It’s really a matter of some people not trying hard enough; if blacks would only try harder they could be just as well off as whites.”But the negative attitudes weren’t just explicit. All participants took the Implicit Association Test (IAT), which is designed to reveal unconscious bias. During this test, researchers measure how quickly participants link a white or black face with a “good” word (joy, love, peace) or a “bad” word (terrible, horrible, evil). If it takes a participant longer to link a black face to good words than it does to link a white face, then that is considered showing more negative attitudes toward blacks.Results showed that participants who played the violent version of the game as a black avatar were more likely to associate black faces with negative words on the IAT than were those who played as a white avatar.”The media have the power to perpetuate the stereotype that blacks are violent, and this is certainly seen in video games,” Bushman said.”This violent stereotype may be more prevalent in video games than in any other form of media because being a black character in a video game is almost synonymous with being a violent character.”This stereotype can affect people’s actions, as found in the second experiment.In this study, 141 white college students (65 percent female) played one of two violent games: WWE Smackdown vs. RAW 2010 or Fight Night Round 4. These games both used a third-person perspective, allowing the player to see his or her avatar’s race throughout the game.Again, participants were assigned to play as a black or a white avatar. After playing, the participants completed another version of the IAT, which took an implicit measure of the stereotype that blacks are violent. …

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One out of two parents do not see their child’s weight problem

One out of two parents of children with overweight feel that their child’s weight is normal. Four out of ten parents of children with overweight or obesity are even worried that their child will get too thin. These are the findings of a European study of parents of more than 16,000 children, including 1,800 children from Sweden.The research is a part of a European study that comprises a total of 16,220 children in the ages 2-9, of which 1,800 live in Partille, Alingss and Mlndal in Sweden.Estimates of the weight statusIn Susann Regber’s dissertation, the parents were asked to estimate their child’s weight status and health, and to describe their own worries about their child’s becoming overweight or underweight. The parents’ perceptions were then compared with the children’s actual measurements.Worries about underweightAmong other findings, the studies show that:• Around 40 per cent of parents of children with both overweight and obesity are worried that the child will become underweight. Among parents of children who are already underweight, the proportion that are worried about it is 33 per cent.• One out of two parents of a child with overweight in Central and Northern Europe perceived their child’s weight as normal. In Southern Europe, the same figure was 75 per cent.Major significance”How parents perceive their child’s weight status is of major significance to being able to promote a healthy weight development. Our studies show that the parents’ insight into obesity in their children indeed grows in pace with the child’s age and higher BMI in the child, but also that a weight development at preschool age can go from overweight to obesity without necessary lifestyle changes being made,” says Susann Regber, who is presenting the findings in her dissertation:”Many parents simply do not see the increase in growth, and are dependent on objective information from, for instance, child welfare centers and school health care to act.” A simple measure may be to introduce a routine in pediatric and school health care to always show the child’s BMI curve to the parents.Many obstacles to healthy habitsAs a part of the studies, the researchers arranged group discussions with children and parents. In the talks, the parents emphasized that there are many obstacles to being able to maintain healthy eating habits: long working days, financial limitations, and the constant availability and marketing of unhealthy food and drinks.Another problem that was brought up was that other family members, like spouses and grandparents, broke the rules set up in the home.”But the parents also emphasized examples that promoted good eating habits, like children being served good, healthy food at day-care and in school,” says Susann Regber.The findings in this dissertation are based on the European research project IDEFICS, where researchers from various parts of Europe are studying lifestyle, diet and obesity as well as their health effects on children between the ages of 2 and 10 years.The dissertation Barriers and Facilitators of Health Promotion and Obesity Prevention in Early Childhood: A Focus on Parents- Results from the IDEFICS Study was defended on February 28.Link to dissertation: http://hdl.handle.net/2077/34815Story Source:The above story is based on materials provided by University of Gothenburg. The original article was written by Krister Svahn. Note: Materials may be edited for content and length.

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Exotic plant species alter ecosystem productivity

In their joint publication in the journal Ecology Letters German and American biologists have reported an increase in biomass production in ecosystems colonised by non-native plant species. In the face of climate change, these and other changes to ecosystems are predicted to become more frequent, according to the researchers.All over the world, plant and animal species are increasingly encroaching upon ecosystems where they don’t belong as a result of human influence. This phenomenon is known as a biological invasion. Observational studies on biological invasions show that the invasion of non-native plant species can alter ecosystems. One important aspect of this is biomass production: compared to intact ecosystems, the productivity of ecosystems with non-native species is considerably higher. “In such purely observational studies however, it is not possible to differentiate between cause and effect,” says Dr. Harald Auge from the Helmholtz Center for Environmental Research (UFZ). “The question is whether exotic plant species prefer to colonise more productive ecosystems, or whether increased productivity is a result of the invasion.”To get to the bottom of this question, UFZ researchers joined forces with colleagues from the Martin-Luther University Halle-Wittenberg, the University of Montana, the University of California and the US Forest Service and staged invasions by setting up experimental sites in three disparate grassland regions -in Central Germany, Montana and California, on which 20 native plant species (from the respective region) and 20 exotic plant species were sown. Researchers investigated whether and to which extent herbivorous small mammals such as mice, voles or ground squirrels as well as mechanical disturbance to the soil would influence exotic plant species colonizing ability.”The experimental design was exactly the same for all three regions to ensure comparability. We wanted to find out whether superordinate relationships were playing a role, irrespective of land use, species compositions and climate differences,” explains Dr Auge. …

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Europe may experience higher warming than global average

The majority of Europe will experience higher warming than the global average if surface temperatures rise to 2 C above pre-industrial levels, according to a new study published today.Under such a scenario, temperatures greater than the 2 C global average will be experienced in Northern and Eastern Europe in winter and Southern Europe in summer; however, North-Western Europe — specifically the UK — will experience a lower relative warming.The study, which has been published today, 7 March, in IOP Publishing’s journal Environmental Research Letters, also shows that in the summer, daily maximum temperatures could increase by 3-4 C over South-Eastern Europe and the Iberian Peninsula and rise well above 40 C in regions that already experience some of the highest temperatures in Europe, such as Spain, Portugal and France. Such higher temperatures will increase evaporation and drought.In the winter, the maximum daily temperatures could increase by more than 6 C across Scandinavia and Russia.Lead author of the research Robert Vautard, from Laboratoire des Sciences du Climat et de l’Environnement (CEA/CNRS/UVSQ), said: “The 2 C warming target has mainly been decided among nations as a limit not to exceed in order to avoid possibly dangerous climate change. However, the consequences of such a warming, at the scale of a continent like Europe, have not yet been quantified.”We find that, even for such an ambitious target as 2 C, changes in European climate are significant and will lead to significant impacts.”The study also shows that there will be a robust increase in precipitation over Central and Northern Europe in the winter and Northern Europe in the summer, and that most of the continent will experience an increase in instances of extreme precipitation, increasing the flood risks which are already having significant economic consequences.Southern Europe is an exception, and will experience a general decline in mean precipitation.To arrive at their conclusions, the researchers used an ensemble of 15 regional climate models to simulate climate changes under an A1B scenario, which represents rapid economic growth and a balanced approach to energy sources.In addition to temperature and precipitation changes that may occur, the researchers also investigated atmospheric circulation and winds, but found no significant changes.”Even if the 2 C goal is achieved, Europe will experience impacts, and these are likely to exacerbate existing climate vulnerability. Further work on identifying key hotspots, potential impacts and advancing carefully planned adaptation is therefore needed,” the researchers write in their study.Story Source:The above story is based on materials provided by Institute of Physics. Note: Materials may be edited for content and length.

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New pathway for fear discovered deep within brain

Fear is primal. In the wild, it serves as a protective mechanism, allowing animals to avoid predators or other perceived threats. For humans, fear is much more complex. A normal amount keeps us safe from danger. But in extreme cases, like post-traumatic stress disorder (PTSD), too much fear can prevent people from living healthy, productive lives. Researchers are actively working to understand how the brain translates fear into action. Today, scientists at Cold Spring Harbor Laboratory (CSHL) announce the discovery of a new neural circuit in the brain that directly links the site of fear memory with an area of the brainstem that controls behavior.How does the brain convert an emotion into a behavioral response? For years, researchers have known that fear memories are learned and stored in a small structure in the brain known as the amygdala. Any disturbing event activates neurons in the lateral and then central portions of the amygdala. The signals are then communicated internally, passing from one group of neurons to the next. …

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Humans, urban landscapes increase illness in songbirds, researchers find

Humans living in densely populated urban areas have a profound impact not only on their physical environment, but also on the health and fitness of native wildlife. For the first time, scientists have found a direct link between the degree of urbanization and the prevalence and severity of two distinct parasites in wild house finches.The findings are published in the Feb. 4 issue of the journal PLOS ONE.A team of researchers from Arizona State University made the discovery while investigating intestinal parasites (Isospora sp.) and the canarypox virus (Avipoxvirus) found in house finches. The group also studied the effects of urbanization on the stress response system of the finches.Specifically, the team studied male house finches found at seven sites throughout Maricopa County in central Arizona. Each site varied in the number of people living within one kilometer (about five-eighths of a mile) — from nearly a dozen to over 17 thousand.Researchers also considered whether the soil in each location had been disturbed and the vegetation cultivated or left in a natural state. In all, they quantified 13 different urbanization factors. They also assessed the potential relationship between oxidative stress, the degree of urbanization and parasitic infections to see whether increased infections are associated with increased stress levels.”Several studies have measured parasite infection in urban animals, but surprisingly we are the first to measure whether wild birds living in a city were more or less infected by a parasite and a pathogen, as well as how these infections are linked to their physiological stress,” said Mathieu Giraudeau, a post-doctoral associate who previously worked with Kevin McGraw, ASU associate professor with the School of Life Sciences. Giraudeau now works with the University of Zurich in Switzerland.”We also capitalized on data gathered by the Central Arizona Phoenix-Long Term Ecological Research program to accurately measure the degree to which the landscapes at each study site were natural or disturbed by humans,” added Giraudeau.House finches (Haemorhous mexicanus) are native to the desert southwest in the U.S., but are now found abundantly throughout North America. Male finches are five to six inches long and have colorful red, orange or yellow crown, breast and rump feathers.Emerging infectious diseases transmitted from animals to humansAccording to the study, more than half of the world’s population now lives in cities. Natural habitats and ecosystems have been dramatically altered from their original states, and there is rising concern about the spread of diseases that can be passed from urban wildlife to humans. …

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Do you have a sweet tooth? Honeybees have a sweet claw

New research on the ability of honeybees to taste with claws on their forelegs reveals details on how this information is processed, according to a study published in the open-access journal, Frontiers in Behavioral Neuroscience.Insects taste through sensilla, hair-like structures on the body that contain receptor nerve cells, each of which is sensitive to a particular substance. In many insects, for example the honeybee, sensilla are found on the mouthparts, antenna and the tarsi — the end part of the legs. Honeybees weigh information from both front tarsi to decide whether to feed, finds the latest study led by Dr. Gabriela de Brito Sanchez, researcher, University of Toulouse, and Dr. Martin Giurfa, Director of the Research Centre on Animal Cognition, University of Toulouse, France.Hundreds of honeybees were included in the study. Sugary, bitter and salty solutions were applied to the tarsi of the forelegs to test if this stimulated the bees to extend or retract their tongue — reflex actions that indicate whether or not they like the taste and are preparing to drink. Results revealed that honeybee tarsi are highly sensitive to sugar: even dilute sucrose solutions prompted the bees to extend their tongue. Measurements of nerve cell activity showed that the part of the honeybee tarsus most sensitive to sugary tastes is the double claw at its end. Also, the segments of the tarsus before the claws, known as the tarsomeres, were found to be highly sensitive to saline solutions.”Honeybees rely on their color vision, memory, and sense of smell and taste to find nectar and pollen in the ever-changing environment around the colony,” says Dr. Giurfa. …

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Pesticides increase risk for Parkinson’s disease: Certain people may be more susceptible

Previous studies have shown the certain pesticides can increase the risk for developing Parkinson’s disease. Now, UCLA researchers have now found that the strength of that risk depends on an individual’s genetic makeup, which in the most pesticide-exposed populations could increase the chances of developing the debilitating disease by two- to six-fold.In a previous study published January 2013 in the Proceedings of the National Academy of Sciences, the UCLA research team discovered a link between Parkinson’s and the pesticide benomyl, a fungicide that has been banned by the U.S. Environmental Protection Agency. That study found that benomyl inhibited an enzyme called aldehyde dehydrogenase (ALDH), which converts aldehydes highly toxic to dopamine cells into less toxic agents, and therefore contributed to the development of Parkinson’s.In this study, UCLA researchers tested a number of other pesticides and found 11 that also inhibit ALDH and increase the risk of Parkinson’s, and at much lower levels than those at which they are currently being used, said study lead author Jeff Bronstein, a professor of neurology and director of movement disorders at UCLA.Bronstein said the team also found that people with a common genetic variant of the ALDH2 gene are particularly sensitive to the effects of ALDH-inhibiting pesticides, and were two to six times more likely to develop Parkinson’s than those without the variant when exposed to these pesticides.The results of the epidemiological study appear Feb. 5, 2014 in the online issue of Neurology, the medical journal of the American Academy of Neurology.”We were very surprised that so many pesticides inhibited ALDH and at quite low concentrations, concentrations that were way below what was needed for the pesticides to do their job,” Bronstein said. “These pesticides are pretty ubiquitous, and can be found on our food supply and are used in parks and golf courses and in pest control inside buildings and homes. So this significantly broadens the number of people at risk.”The study compared 360 patients with Parkinson’s in three agriculture heavy Central California counties to 816 people from the same area who did not have Parkinson’s. Researchers focused their analyses on individuals with ambient exposures to pesticides at work and at home, using information from the California Department of Pesticide Regulation.In the previous PNAS study, Bronstein and his team determined the mechanism that leads to increased risk. Exposure to pesticides starts a cascade of cellular events, preventing ALDH from keeping a lid on DOPAL, a toxin that naturally occurs in the brain. When ALDH does not detoxify DOPAL sufficiently, it accumulates, damages neurons and increases an individual’s risk of developing Parkinson’s.”ALDH inhibition appears to be an important mechanism by which these environmental toxins contribute to Parkinson’s pathogenesis, especially in genetically vulnerable individuals,” said study author Beate Ritz, a professor of epidemiology at the Fielding School of Public Health at UCLA. …

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World’s first butterfly bacteria sequenced: Suprising events found during metamorphosis

For the first time ever, a team led by the University of Colorado Boulder has sequenced the internal bacterial makeup of the three major life stages of a butterfly species, a project that showed some surprising events occur during metamorphosis.The team, led by CU-Boulder doctoral student Tobin Hammer, used powerful DNA sequencing methods to characterize bacterial communities inhabiting caterpillars, pupae and adults of Heliconius erato, commonly known as the red postman butterfly. The red postman is an abundant tropical butterfly found in Central and South America.The results showed the internal bacterial diversity of the red postman was halved when it morphed from the caterpillar to the chrysalis, or pupal stage, then doubled after the pupae turned into active adult butterflies. The study is important because communities of bacteria inhabiting other insects have been shown to affect host nutrition, digestion, detoxification and defense from predators, parasites and pathogens, said Hammer of the ecology and evolutionary biology department.”What we saw was that the microbial community simplified and reorganized itself during the transition from caterpillar to pupa,” he said. “Then we saw the diversity double after the adult butterflies had emerged and began going about their business of feeding. That was a little surprising to us.”A paper on the subject was published online Jan. 23 in the journal PLOS ONE. Study co-authors on the paper included CU-Boulder Associate Professor Noah Fierer of the ecology and environmental biology department and W. Owen McMillan of the Smithsonian Tropical Research Institute in Panama City, Panama. The butterflies were collected at a field site in Gamboa, Panama, and data analysis was done at CU-Boulder.The collection of microorganisms on a single animal, collectively known as the microbiome, has become important because such bacterial groups have been found to affect metabolic and developmental processes from food digestion and vitamin synthesis to possible brain function, say experts. While the average human is made up of about 1 trillion cells, scientists now estimate each of us has a staggering 10 trillion bacteria — essentially 10 bacteria for every human cell, Hammer said.”Butterflies are ecologically and scientifically important, and their transformation from caterpillar to chrysalis to winged adult is one of the most remarkable phenomena of the natural world,” he said. …

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Drug trafficking leads to deforestation in Central America

Add yet another threat to the list of problems facing the rapidly disappearing rainforests of Central America: drug trafficking.In an article in the journal Science, seven researchers who have done work in Central America point to growing evidence that drug trafficking threatens forests in remote areas of Honduras, Guatemala, Nicaragua and nearby countries.Traffickers are slashing down forests, often within protected areas, to make way for clandestine landing strips and roads to move drugs, and converting forests into agribusinesses to launder their drug profits, the researchers say.Much of this appears to be a response to U.S.-led anti-trafficking efforts, especially in Mexico, said Kendra McSweeney, lead author of the Science article and an associate professor of geography at The Ohio State University.”In response to the crackdown in Mexico, drug traffickers began moving south into Central America around 2007 to find new routes through remote areas to move their drugs from South America and get them to the United States,” McSweeney said.”When drug traffickers moved in, they brought ecological devastation with them.”For example, the researchers found that the amount of new deforestation per year more than quadrupled in Honduras between 2007 and 2011 — the same period when cocaine movements in the country also spiked.McSweeney is a geographer who has done research in Honduras for more than 20 years, studying how indigenous people interact with their environment. The drug trade is not something she would normally investigate, but it has been impossible to ignore in recent years, she said.”Starting about 2007, we started seeing rates of deforestation there that we had never seen before. When we asked the local people the reason, they would tell us: “los narcos” (drug traffickers).”There were other indications of drug trafficking taking place in the area.”I would get approached by people who wanted to change $20 bills in places where cash is very scarce and dollars are not the normal currency. When that starts happening, you know narcos are there,” she said.When McSweeney talked to other researchers in Central America, they had similar stories.”The emerging impacts of narco-trafficking were being mentioned among people who worked in Central America, but usually just as a side conversation. We heard the same kinds of things from agricultural specialists, geographers, conservationists. Several of us decided we needed to bring more attention to this issue.”In the Science article, McSweeney and her co-authors say deforestation starts with the clandestine roads and landing strips that traffickers create in the remote forests. The infusion of drug cash into these areas helps embolden resident ranchers, land speculators and timber traffickers to expand their activities, primarily at the expense of the indigenous people who are often key forest defenders.In addition, the drug traffickers themselves convert forest to agriculture as a way to launder their money. While much of this land conversion occurs within protected areas and is therefore illegal, drug traffickers often use their profits to influence government leaders to look the other way.McSweeney said more research is needed to examine the links between drug trafficking and conservation issues. But there is already enough evidence to show that U.S. drug policy has a much wider effect than is often realized.”Drug policies are also conservation policies, whether we realize it or not,” McSweeney said.”U.S.-led militarized interdiction, for example, has succeeded mainly in moving traffickers around, driving them to operate in ever-more remote, biodiverse ecosystems. …

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Fat black holes grown up in ‘cities’: Observational result using virtual observatory

Oct. 17, 2013 — Massive black holes of more than one million solar masses exist at the center of most galaxies. Some of the massive black holes are observed as active galactic nuclei (AGN) which attract surrounding gas and release huge amounts of energy.How does a massive black hole get “fat”? One possibility is that mutual interaction between galaxies leads to the growth of a black hole. If this theory is correct, there must be some relationship between properties of an supermassive black hole and environment of its host galaxy. Previous studies revealed that radio-loud AGNs are in the overcrowded region. However, it is still not clear that relation between the mass of an central black hole and the environment around an active galaxy (galaxies hosting AGNs). This is why the research team explored the distribution of galaxies surrounding active galaxies.The research team utilized the “Virtual Observatory” to examine many massive black holes and the environment of active galaxies.The Virtual Observatory is a system to make integrated use of various astronomical databases around the world via sharing over the Internet. The Astronomy Data Center of NAOJ has been developing an original portal site for the virtual observatory. To begin with this research, the team collected the data on more than 10,000 AGN whose black hole mass had been already measured by spectroscopic observation with SDSS (Note 1). …

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Housework isn’t as healthy as people think

Oct. 17, 2013 — Claiming housework as exercise may be a mistake finds research in BioMed Central’s open access journal BMC Public Health. For the same amount of time people who included housework in their self recorded moderate to vigorous physical activity tended to be heavier than those whose time was spent in other forms of exercise.Share This:The UK Department of Health recommends 150 minutes of moderate to vigorous physical activity a week. When questioned about their activity levels only 43% of the population reported meeting or exceeding these guidelines, and two thirds of these people included at least 10 minutes of housework in their weekly tally.This analysis of data, from the Sport NI Sport & Physical Activity Survey (SAPAS) by the University of Ulster, showed that people who included housework as part of their weekly exercise tended to be heavier. Prof Marie Murphy who led this study commented, “Housework is physical activity and any physical activity should theoretically increase the amount of calories expended. But we found that housework was inversely related to leanness which suggests that either people are overestimating the amount of moderate intensity physical activity they do through housework, or are eating too much to compensate for the amount of activity undertaken.”Women and older people included higher levels of housework. For women, exclusion of housework from the list of activities meant that only 20% met current activity recommendations. Prof Murphy continued, “When talking to people about the amount of physical activity they need to stay healthy, it needs to be made clear that housework may not be intense enough to contribute to the weekly target and that other more intense activities also need to be included each week.”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 BioMed Central Limited. Note: Materials may be edited for content and length. For further information, please contact the source cited above. …

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Are banana farms contaminating Costa Rica’s crocs?

Sep. 19, 2013 — Shoppers spend over £10 billion on bananas annually and now this demand is being linked to the contamination of Central America’s crocodilians. New research, published in Environmental Toxicology and Chemistry, analyses blood samples from spectacled caiman in Costa Rica and finds that intensive pesticide use in plantations leads to contaminated species in protected conservation areas.”Banana plantations are big business in Costa Rica, which exports an estimated 1.8 million tonnes per year; 10% of the global total,” said author Paul Grant from Stellenbosch University, South Africa. “The climate of the country’s North East is ideal for bananas; however, the Rio Suerte, which flows through this major banana producing area, drains into the Tortuguero Conservation Area.”Tortuguero is home to the spectacled caiman (Caiman crocodilus), one of the most common species of crocodilian in Central America. This freshwater predator is known to be highly adaptive, feeding on fish, crustaceans and in the case of larger specimens, wild pigs.Due to the increased global demand for fruit, pesticide use has more than doubled across Central America in the past twenty years. In Costa Rica, which ranks second in the world for intensity of pesticide use, the problem of contamination is compounded by environmental conditions and lax enforcement of regulations.”Frequent heavy rains can wash pesticides from plantation areas, leading to contamination and the reapplication of sprays to the crops,” said Grant. “Without adequate enforcement of regulations dangerous practices such as aerial spraying close to streams or washing application equipment in rivers also contributes to contamination downstream.”The team collected blood samples from 14 adult caiman and analyzed them for traces of 70 types of pesticide. Caiman within the high intensity banana crop watershed of Rio Suerte had higher pesticide burdens relative to other more remote locations.The nine pesticides detected in the caiman blood were identified as insecticides. Of these seven were listed as Persistent Organic Pollutants (POPS), banned under the 2011 Stockholm Convention.”Caiman near banana plantations had higher pesticide burdens and lower body condition,” said Grant. “This suggests that either pesticides pose a health risk to caiman, or that pesticides harm the habitat and food supply of caiman, thereby reducing the health of this predator.”As long-lived species atop the food chain crocodilians provide an integrated assessment of the fate of pesticides in tropical areas and can be indicative of pesticide damage throughout the ecosystem.”Caiman and other aquatic species have been exposed to pesticides from upstream banana plantations, even in remote areas of a national wilderness area,” concluded Grant. …

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Analysis of herbal products shows contamination is common

Oct. 10, 2013 — Most herbal products, available to buy as alternative medicines, may be contaminated. Reporting in BioMed Central’s open access journal BMC Medicine researchers demonstrate the presence of contamination and substitution of plant species in a selection of herbal products using DNA barcoding.Share This:There is currently no best practice for identifying plant species in herbal products. Traditionally plants are identified through the appearance of the whole plant. This method is not useful though when analyzing processed plant material. DNA barcoding analyses a short genetic sequence from the plant’s genome and identifies small differences that allows species identification. In this new study the researchers used barcoding to examine the plant species found in a sample of herbal plant products.The results showed that 59% of the products contained plant species not listed on the labels. Over two thirds of the products tested had plant species present which were a substitution for the plants listed on the label and a third of products also contained other species that may be a filler or contamination.According to the World Health Organization, the adulteration of herbal products is a threat to consumer safety. In this current analysis the researchers detected plant species that could pose serious health risks when consumed. The results revealed plant species with known toxicity, side effects and/or negatively interact with other herbs, supplements, or medications were present in some products.The authors concluded that the contamination and substitution dilute the effectiveness of otherwise useful remedies, lowering the perceived value of all related products because of a lack of consumer confidence in them. …

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Calculating the true cost of a ton of mountaintop coal

Sep. 11, 2013 — To meet current U.S. coal demand through surface mining, an area of the Central Appalachians the size of Washington, D.C., would need to be mined every 81 days.That’s about 68 square miles — or roughly an area equal to 10 city blocks mined every hour.A one-year supply of coal would require converting about 310 square miles of the region’s mountains into surface mines, according to a new analysis by scientists at Duke University, Kent State University and the Cary Institute for Ecosystem Studies.Creating 310 square miles of mountaintop mine would pollute about 2,300 kilometers of Appalachian streams and cause the loss of carbon sequestration by trees and soils equal to the greenhouse gases produced in a year by 33,600 average U.S. single-family homes, the study found.The study, published today in the peer-reviewed online journal PLOS ONE, is “the first to put an environmental price tag on mountaintop removal coal,” said Brian D. Lutz, assistant professor of biogeochemistry at Kent State, who began the analysis as a postdoctoral research associate at Duke’s Nicholas School of the Environment last year.While many studies have documented the severity of surface mining’s impacts on local ecosystems, few have quantified the region-wide extent of the damage and provided the metrics needed to weigh the environmental costs of mountaintop mining against its economic benefits, Lutz said.”This is a critical shortcoming,” Lutz said, “since even the most severe impacts may be tolerated if we believe they are sufficiently limited in extent.”To help fill the data gap, the study’s authors used satellite images and historical county-by-county coal production data to measure the total area of land mined and coal removed in the Central Appalachian coalfields between 1985 and 2005.They found that cumulative coal production during the 20-year period totaled 1.93 billion tons, or about two years’ worth of current U.S. coal demand. To access the coal, nearly 2,000 square kilometers of land was mined — an area similar in size to the Great Smoky Mountains National Park.The team calculated the average per-ton environmental costs of this activity by using previously reported assessments of the extent of stream impairment and loss of carbon sequestration potential associated with every hectare of land mined.”Given 11,500 tons of coal was produced for every hectare of land disturbed, we estimate 0.25 centimeters of stream length was impaired and 193 grams of potential carbon sequestration was lost for every ton of coal extracted,” said Emily S. Bernhardt, associate professor of biogeochemistry at Duke’s Nicholas School of the Environment.That doesn’t sound like much until you put it in perspective, she stressed.”Based on the average carbon sequestration potential of formerly forested mine sites that have been reclaimed into predominantly grassland ecosystems, we calculate it would take around 5,000 years for any given hectare of reclaimed mine land to capture the same amount of carbon that is released when the coal extracted from it is burned for energy,” she said.”Even on those rare former surface mines where forest regrowth is achieved, it would still take about 2,150 years for the carbon sequestration deficit to be erased,” said Lutz, who earned his PhD from Duke in 2011.”This analysis shows that the extent of environmental impacts of surface mining practices is staggering, particularly in terms of the relatively small amount of coal that is produced,” said William H. Schlesinger, president of the Cary Institute of Ecosystem Studies in Millbrook, N.Y. Schlesinger is James B. …

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Changing part of central line could reduce hospital infections

Sep. 10, 2013 — Simply replacing the connector in the IV system in patients with central lines could help reduce deadly bloodstream infections, researchers at Georgia Regents University have found.A central line or central catheter is a tube placed in a patient’s arm or chest to help deliver fluids, blood, or medications through the large veins near the heart. A connector sits at the top of the catheter and serves as the entry point for the fluid pathway inside — any fluid that goes in or comes out of the body, goes through the connector.Most connectors use positive or negative pressure — either pushing fluid out or drawing blood in — when catheters are disconnected for flushing and cleaning. Ironically, it’s during that process — designed to clean the catheter and ultimately reduce the chance of infection — that germs find their way into the bloodstream causing an often dangerous blood infection. Nearly 250,000 central line-associated bloodstream infections happen in hospitals each year, according to the Centers for Disease Control and Prevention. Mortality rates on CLABSIs range from 12 to 25 percent.Treating them also costs health care systems billions of dollars each year. “We know that both positive and negative needleless connectors have been associated with higher CLABSI rates, so we decided to see what role a zero fluid displacement connector would play in infection control,” said Dr. Cynthia C. Chernecky, a Professor of Nursing at GRU and corresponding author on the study published in the American Journal of Infection Control.As their name indicates, zero fluid displacement connectors cause no reflux of fluids — out or in — during disconnection and connection.Researchers analyzed data in six acute care settings in five states and found that the number of infections decreased by 60 percent when positive connectors were replaced with zero fluid displacement connectors and by 94 percent when negative connectors were replaced with the zero connectors for central line IV therapy.”We estimate that replacing the connector devices saved about 13 lives in the acute care settings in this study,” Chernecky said. In addition to saving lives, more than $3 million was saved on health care costs. …

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Yin-yang effect of sodium and chloride presents salt conundrum

Sep. 8, 2013 — Eat less salt’ is a mantra of our health-conscious times and is seen as an important step in reducing heart disease and hypertension.Too much salt in the diet — and specifically sodium — is widely acknowledged as a major risk factor for high blood pressure however, scientists have found that salt’s other oft-overlooked constituent chloride might also play an important role.A study by researchers at the University of Glasgow has revealed that low chloride levels in the blood is an independent indicator of mortality risk in people with hypertension. The role of chloride in hypertension has received little attention from scientists hitherto.After analysing data from almost 13,000 patients with high blood pressure, followed up over 35 years, the researchers found that low levels of chloride was associated with a higher risk of death and cardiovascular disease.The group with the lowest level of chloride in their blood had a 20% higher mortality rate compared to the other subjects. The results are published in the journal Hypertension.Dr Sandosh Padmanabhan of the Institute of Cardiovascular and Medical Sciences, said: “Sodium is cast as the villain for the central role it plays in increasing the risk of high blood pressure, with chloride little more than a silent extra in the background.”However, our study has put the spotlight on this under-studied chemical to reveal an association between low levels of chloride serum in the blood and a higher mortality rate, and surprisingly this is in the opposite direction to the risks associated with high sodium.”It is likely that chloride plays an important part in the physiology of the body and we need to investigate this further.”Chloride is already measured as part of routine clinical screening and so monitoring of chloride levels could easily be incorporated into clinical practice to identify individuals at high risk.Dr Padmanabhan added: “The results we see from this study are confounding against the knowledge that excess salt is a bad thing, yet higher levels of chloride in the blood seems to be an independent factor that is associated with lower mortality and cardiovascular risk. We seem to have entered a grey area here that requires further investigation.”It is too early to draw any conclusions about relating this finding to salt intake and diet. We need more research to establish exactly what the relationship between chloride and health risk is.”

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Bizarre alignment of planetary nebulae

Sep. 4, 2013 — The final stages of life for a star like our Sun result in the star blowing its outer layers out into the surrounding space, forming objects known as planetary nebulae in a wide range of beautiful and striking shapes. One type of such nebulae, known as bipolar planetary nebulae, create ghostly hourglass or butterfly shapes around their parent stars.All these nebulae formed in different places and have different characteristics. And neither the individual nebulae, nor the stars that formed them, would have interacted with other planetary nebulae. However, a new study by astronomers from the University of Manchester, UK, now shows surprising similarities between some of these nebulae: many of them line up in the sky in the same way [1].”This really is a surprising find and, if it holds true, a very important one,” explains Bryan Rees of the University of Manchester, one of the paper’s two authors. “Many of these ghostly butterflies appear to have their long axes aligned along the plane of our galaxy. By using images from both Hubble and the NTT we could get a really good view of these objects, so we could study them in great detail.”The astronomers looked at 130 planetary nebulae in the Milky Way’s central bulge. They identified three different types [2], and peered closely at their characteristics and appearance.”While two of these populations were completely randomly aligned in the sky, as expected, we found that the third — the bipolar nebulae — showed a surprising preference for a particular alignment,” says the paper’s second author Albert Zijlstra, also of the University of Manchester. “While any alignment at all is a surprise, to have it in the crowded central region of the galaxy is even more unexpected.”Planetary nebulae are thought to be sculpted by the rotation of the star system from which they form. This is dependent on the properties of this system — for example, whether it is a binary [3], or has a number of planets orbiting it, both of which may greatly influence the form of the blown bubble. …

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Dueling infections: Parasitic worms limit the effects of giardia, and vice versa

Aug. 30, 2013 — If the idea of hookworms makes you shudder, consider this: Those pesky intestinal parasites may actually help your body ward off other infections, and perhaps even prevent autoimmune and other diseases.Studying members of the Tsimane, an indigenous population in the lowlands of Central Bolivia, UC Santa Barbara anthropologists Aaron Blackwell and Michael Gurven found that individuals infected by helminths — parasitic worms — were less likely than their counterparts to suffer from giardia, an intestinal malady caused by a flagellated protozoa. Similarly, those with giardia tended to be less infected by helminths. The researchers’ findings appear in the Proceedings of the Royal Society B.Treatment of one parasite also led to a greater likelihood of having the other later, the researchers found. The study used longitudinal data on 3,275 Tsimane collected over six years, which thereby permitted the authors to make more definitive causal inferences. This represents a distinct improvement over common correlative studies.”People living in developing countries are often burdened by simultaneous infections,” said Blackwell, an assistant professor of anthropology and the paper’s lead author. “The key finding in this study is that worms and giardia have antagonistic effects on one another, such that infection with one limits infection with the other.”The researchers’ findings also suggest that treating one infection might allow the other to run rampant, which raises questions about currently accepted protocols for dealing with parasites.According to Gurven, a professor of anthropology and co-director of the Tsimane Health and Life History Project, a collaboration between UCSB and the University of New Mexico, more than 1.5 billion people in the developing world have soil-transmitted intestinal worms. To determine which particular individuals are infected — and require treatment — however, is a very costly endeavor.”There are campaigns in many developing countries to give every child under five de-worming medication, but if the basic infrastructure that leads to infection doesn’t change — like sanitation and access to shoes and clean water — re-infection is likely to happen within six months,” he said. “And if intestinal worms are protective against giardia, there’s a tradeoff, and then the question is, which of the two is worse?”Diagnosis and treatment of parasites usually happen on an organism-by-organism basis, continued Gurven, a co-author of the paper. Further, he argues that in the case of hookworm and giardia, the relationship between the parasites needs to be taken into account in order to maintain the overall health of the individual involved.That one intestinal parasite has the ability to limit the pervasiveness of another also sheds light on the significance of parasites in general. …

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