The Race for Solar
|Angela Stark||April 24th 2012|
|High-Efficiency Solar Cell|
To produce the maximum amount of energy, solar cells are designed to absorb as much light from the Sun as possible. Now researchers from the University of California, Berkeley, have suggested – and demonstrated – a counterintuitive concept: solar cells should be designed to be more like LEDs, able to emit light as well as absorb it. "What we demonstrated is that the better a solar cell is at emitting photons, the higher its voltage and the greater the efficiency it can produce," says Eli Yablonovitch, principal researcher and UC Berkeley professor of electrical engineering. Since 1961, scientists have known that, under ideal conditions, there is a limit to the amount of electrical energy that can be harvested from sunlight hitting a typical solar cell. This absolute limit is, theoretically, about 33.5 percent. That means that at most 33.5 percent of the energy from incoming photons will be absorbed and converted into useful electrical energy.
Yet for five decades, researchers were unable to come close to achieving this efficiency: as of 2010, the highest anyone had come was just more than 26 percent. (This is for flat-plate, "single junction" solar cells, which absorb light waves above a specific frequency. "Multi-junction" cells, which have multiple layers and absorb multiple frequencies, are able to achieve higher efficiencies.)
More recently, Yablonovitch and his colleagues were trying to understand why there has been such a large gap between the theoretical limit and the limit that researchers have been able to achieve. As they worked, a "coherent picture emerged," says Owen Miller, a graduate student at UC Berkeley and a member of Yablonovitch's group. They came across a relatively simple, if perhaps counterintuitive, solution based on a mathematical connection between absorption and emission of light. "Fundamentally, it's because there's a thermodynamic link between absorption and emission," Miller says. Designing solar cells to emit light – so that photons do not become "lost" within a cell – has the natural effect of increasing the voltage produced by the solar cell. "If you have a solar cell that is a good emitter of light, it also makes it produce a higher voltage," which in turn increases the amount of electrical energy that can be harvested from the cell for each unit of sunlight, Miller says. The theory that luminescent emission and voltage go hand in hand is not new. But the idea had never been considered for the design of solar cells before now, Miller continues. Read more ..
The Graphene Edge
|R. Colin Johnson||April 24th 2012|
|5-layer graphene/insulator array|
Graphene has been courted as the miracle material of the future, since different formulations have been fabricated into conductors, semiconductors and insulators. Now IBM has added photonic to the list by demonstrating a graphene/insulator superlattice that achieves a terahertz frequency notch filter and a linear polarizer, devices which could be useful in future mid- and far-infrared photonic devices, including detectors, modulators and three-dimensional metamaterials.
"In addition to its good electrical properties, graphene also has exceptional optical properties. In particular, it absorbs light from the far-infrared to to the ultra-violet," said IBM Fellow Phaedon Avouris. "The terahertz range was of particular interest to IBM, because these frequencies can penetrate paper, wood and other solid objects for security applications. Unfortunately, today there are very few ways of manipulating terahertz waves such as polarizing and filtering it, but because graphene operates well at terahertz frequencies we have concentrating on creating these types of devices." Read more ..
The Edge of Nature
University of Copenhagen
Copenhagen Zoo and University of Copenhagen have in collaboration developed a new and revolutionary, yet simple and cheap, method for tracking mammals in the rainforests of Southeast Asia. They collect leeches from tropical jungles, which have been sucking blood from mammals, and subsequently analyse the blood for mammal DNA. By using this method, the researchers can get an overview of the biodiversity of the mammals without having to find them.
"It is not unusual that unknown mammals appear on local markets and end up in soup pots – without scientists knowing of it. Therefore, the new method is important to obtain knowledge of what hides in the jungle - regarding both known and unknown species. I am convinced that the new method is not only useful in Southeast Asia, but can be used in many other parts of the world where such leeches exist," explains Tom Gilbert, professor at the Centre for GeoGenetics, University of Copenhagen, and one of the initiators of the project together with Mads Bertelsen from Copenhagen Zoo. Approximately a quarter of the world’s mammal species are threatened with extinction. However, it is difficult and expensive to monitor mammal species and populations living in impassable rainforest areas around the globe. Read more ..
Edge Of Archaeology
|Dr. Hilary Glover||April 23rd 2012|
Analysis of ancient mitochondrial DNA (mtDNA) has been used to establish migration and population patterns for American indigenous cultures during the time before Christopher Columbus sailed to the Americas. New research published in BioMed Central's open access journal BMC Genetics has used more detailed DNA analysis of individuals from Arequipa region to identify the family relationships and burial traditions of ancient Peru. The social unit (ayllu) of Native South Americans is thought to be based on kin relationships. The establishment of ayllu-based communities is also associated with funereal monuments (chullpas) which are thought to be important social sites not only because of their religious importance but because they housed the venerated ayllu's ancestors.
Ancestor worship and a belief in a common ancestor, central to the ayllu, still exists in the traditions of the Q'ero community. Researchers from University of Warsaw, in collaboration with Universidad Catolica de Santa Maria, used DNA analysis to reconstruct the family trees of individuals buried in six chullpas near the Coropuna volcano is southern Peru. Despite prior looting, the unique nature of this site, 4000m up the Cora Cora mountain, allowed an extraordinary preservation of human remains and of DNA within both teeth and bone. mtDNA analysis showed that the groups were of Andean origin and indicated a 500 year continuity, up to modern Andeans, without any major impact by European colonisation. Read more ..
The Medical Edge
|Nicole Casal Moore||April 23rd 2012|
|Caitlin Winget shows James Azazili the Hemafuse blood syringe.|
In parts of the world without reliable electricity, a pedal-powered nebulizer could provide life-saving asthma treatments. Small wax-filled sleeping bags could keep premature infants warm. A salad spinner centrifuge for blood samples could help clinicians diagnose anemia.
University of Michigan researchers have cataloged more than 100 such technologies in a new wiki of medical devices designed for resource-limited settings. The Global Health Medical Device Compendium, an open-source inventory, is hosted by the popular appropriate technology wiki Appropedia. It is expected to serve as an important communication vehicle for end users, non-governmental organizations, researchers and others to help advance such technologies.
Developing nations import roughly 90 percent of their medical technologies from higher-income countries. But systems tested in controlled settings in high tech hospitals often don't work as intended in places where continuous electricity, replacement parts, clean water, and appropriate training aren't always accessible. Read more ..
Edge of Space
|Andrea Elyse Messer||April 22nd 2012|
Autonomous, self-replicating robots -- exobots -- are the way to explore the universe, find and identify extraterrestrial life and perhaps clean up space debris in the process, according to a Penn State engineer, who notes that the search for extraterrestrial intelligence (SETI) is in its 50th year.
"The basic premise is that human space exploration must be highly efficient, cost effective, and autonomous as placing humans beyond low Earth orbit is fraught with political economic, and technical difficulties," John D. Mathews, professor of electrical engineering, reported in the current issue of the Journal of the British Interplanetary Society.
If aliens are out there, they have the same problems we do: they need to conserve resources, are limited by the laws of physics and they may not even be eager to meet us, according to Mathews.
He suggests that "only by developing and deploying self-replicating robotic spacecraft -- and the incumbent communications systems -- can the human race efficiently explore even the asteroid belt, let alone the vast reaches of the Kuiper Belt, Oort Cloud, and beyond." Mathews assumes that any extraterrestrial would need to follow a similar path to the stars, sending robots rather than living beings, which would explain why SETI has not succeeded to date. Read more ..
The Edge of Space
|David A. Aguilar||April 22nd 2012|
Harvard-Smithsonian Center for Astrophysics
New research suggests that billions of stars in our galaxy have captured rogue planets that once roamed interstellar space. The nomad worlds, which were kicked out of the star systems in which they formed, occasionally find a new home with a different sun. This finding could explain the existence of some planets that orbit surprisingly far from their stars, and even the existence of a double-planet system.
"Stars trade planets just like baseball teams trade players," said Hagai Perets of the Harvard-Smithsonian Center for Astrophysics.
The study, co-authored by Perets and Thijs Kouwenhoven of Peking University, China, will appear in the April 20th issue of The Astrophysical Journal.
To reach their conclusion, Perets and Kouwenhoven simulated young star clusters containing free-floating planets. They found that if the number of rogue planets equaled the number of stars, then 3 to 6 percent of the stars would grab a planet over time. The more massive a star, the more likely it is to snag a planet drifting by. Read more ..
The Medical Edge
|Research In Action|
Researchers at National Jewish Health have discovered a novel genetic mechanism of immune deficiency. Magdalena M. Gorska, MD, PhD, and Rafeul Alam, MD, PhD, identified a mutation in Unc119 that causes immunodeficiency known as idiopathic CD4 lymphopenia. Unc119 is a signaling protein that activates and induces T cell proliferation. The mutation impairs Unc119 ability to activate T cells. “A better understanding of the molecular mechanisms associated with this mutation will improve diagnosis and pave the way for development of new therapies,” said Dr. Gorska. Nearly a decade ago Drs. Alam and Gorska identified Unc119 as a novel activator of SRC-type tyrosine kinases, important regulators of cellular function.
Idiopathic CD4 lymphopenia is a rare and heterogeneous syndrome defined by low levels of CD4 T cells in the absence of HIV infection, which predisposes patients to infections and malignancies. Recent research by others had linked the syndrome to reduced activation of the SRC-type kinase known as Lck. The latter kinase is involved in T cell development, activation and proliferation. Read more ..
|Sonia Fernandez||April 21st 2012|
On the second anniversary of the Deepwater Horizon oil platform blowout, a national panel of researchers is providing new insight into what happened in the disaster, as well as a guide for how to deal with such events in the future, and why existing tools were inadequate to predict what lay before them. The study, produced by the Gulf Oil Spill Ecotox Working Group at UC Santa Barbara's National Center for Ecological Analysis and Synthesis (NCEAS), is published in the May issue of the journal Bioscience. It is titled, "A Tale of Two Spills: Novel Science and Policy Implications of an Emerging New Oil Spill Model."
"The old model assumed that oil would simply float up to the surface and accumulate there and along the coastline," said co-author Sean Anderson, an associate professor at California State University Channel Islands. "That model works well for pipeline breaks and tanker ruptures, but it is inadequate for this novel type of deep blowout."
The 2010 Deepwater Horizon oil spill in the Gulf of Mexico was unlike any oil spill science and society had encountered. The blowout occurred at unprecedented depths and released enormous quantities of oil (an estimated 4.9 billion barrels, or 206 million gallons). Marine and wildlife habitats suffered major damage, and, according to authors, the damage continues to happen today, out of sight. Local and regional economies and livelihoods suffered as well.
According to the researchers — a renowned group of ecotoxicologists, oceanographers, and ecologists who convened under the auspices of NCEAS while the spill was still active — the response to clean up and contain the oil followed a framework that assumed the oil's behavior would mimic the more familiar shallow-water and surface spills, despite the fact that the dynamics, fate, and effect of deep-water oil on ecosystems are not understood. "As the Deepwater Horizon spill unfolded, you would hear folks saying things like, 'We all know what happens when oil and water mix; the oil floats.' That wasn't the whole story, and that assumptions and actions that were not the best possible use of our time and effort," said Anderson. Read more ..
Edge of Nature
|Layne Cameron||April 20th 2012|
Michigan State University
By mating with nearly 100 males, queen bees on isolated islands avoid inbreeding and keep colonies healthy.
The results, published in the current issue of PLoS ONE, focused on giant honey bee colonies on Hainan Island, off the coast of China. Since these bees have long been separated from their continental cousins, it was thought that the island bees would be prime candidates for inbreeding as well as having very different genes, said Zachary Huang, Michigan State University entomologist.
“We believed that the island bees would show evidence of the founder effect, or random genetic changes in an isolated population, on a unique sex determination gene from the mainland bees,” he said. “At first we were surprised when we couldn’t document this effect. Looking at it further, I asked myself, ‘Why didn’t I think of this before?’” Read more ..
The Health Edge
|Catriona Kelly ||April 20th 2012|
University of Edinburgh
Scientists have identified a link between different strains of malaria parasites that cause severe disease, which could help develop vaccines or drugs against life-threatening cases of the infection.
Researchers have identified a key protein that is common to many potentially fatal forms of the condition, and found that antibodies that targeted this protein were effective against these severe malaria strains.
The protein has sticky properties that enable it to bind to red blood cells and form dangerous clumps that can block blood vessels. These clumps, or rosettes, can cause severe illness, including coma and brain damage. Presently, between 10 and 20 per cent of people with severe malaria die from it, and the disease – which is spread by blood-sucking mosquitoes – claims about one million lives per year.
Malaria parasites, once in the bloodstream, are able to alter the protein molecules on their surfaces to evade attack by the immune system. These surface proteins are usually poor targets for treatments or vaccines because they are highly variable between different malaria parasite strains. Now, researchers have found that the surface proteins of rosette-forming parasites share similarities that may allow them to act as a target for treatments to block progress of the disease. Read more ..
The Health Edge
|Kelsey Blackburn and James Schirillo||April 20th 2012|
Your best side may be your left cheek, according to a new study by Kelsey Blackburn and James Schirillo from Wake Forest University in the US. Their work shows that images of the left side of the face are perceived and rated as more pleasant than pictures of the right side of the face, possibly due to the fact that we present a greater intensity of emotion on the left side of our face.
Others can judge human emotions in large part from facial expressions. Our highly specialized facial muscles are capable of expressing many unique emotions. Research suggests that the left side of the face is more intense and active during emotional expression. It is also noteworthy that Western artists' portraits predominantly present subjects' left profile.
Blackburn and Schirillo investigated whether there are differences in the perception of the left and right sides of the face in real-life photographs of individuals.
The authors explain: "Our results suggest that posers' left cheeks tend to exhibit a greater intensity of emotion, which observers find more aesthetically pleasing. Our findings provide support for a number of concepts – the notions of lateralized emotion and right hemispheric dominance with the right side of the brain controlling the left side of the face during emotional expression." Read more ..
The Biometric Edge
|Martin Barillas||April 20th 2012|
Cutting Edge Senior Correspondent
AOptix, a developer of advanced optical technologies and products, announced that Morpho, a high-technology company of the Safran group, has become an AOptix strategic partner in the area of biometric technology. With this agreement, AOptix products, including the combined face capture and iris recognition system, InSight® Duo, will be integrated into Morpho’s solutions offered to countries around the world to check the identities of persons crossing their borders on land, sea and air. Morpho provides advanced solutions for border control, detection, identity management, criminal justice, and secure biometric access.
“For years, we have respected AOptix’s commitment to innovation in enhancing iris usability in biometric identification systems. The match between our two companies is natural as we unite to offer biometric solutions for a vast array of applications,” says Bernard Didier, Senior VP, Technology & Strategy at Morpho. “Combining the knowledge and expertise of our two companies in iris and facial recognition solutions will offer tremendous benefits in security and time savings for governments, airports, airlines and the traveling public.” Read more ..
The Safety Edge
|Christoph Hammerschmidt||April 20th 2012|
A technology collaboration between innovITS Advance (UK ITS Centre for Excellence for Transport Telematics and Technology for Sustainable Mobility) and consultancy TRL has led to the creation of an advanced form of pedestrian detection target which will help those specifying and developing automotive safety systems based on pedestrian recognition to test and certify their products in a more flexible, accurate and repeatable manner.
According to innovITS Advance business development manager Steven Warner, pedestrian detection systems are already increasingly being incorporated into new vehicles,but the automotive industry is largely lacking in dummy systems providing a realistic representation of human form and gait to the vehicle's on-board sensor systems. The new TRL-innovITS advance mobile pedestrian target is based around a robust, free standing dummy that provides a realistic human aspect and moves under remote control with a programmable range of speed and acceleration settings.
The dummy emulates the leg motion associated with a normal walking or running gait and can currently be configured for three body sizes: a 50th percentile adult male and adult female, and a 6 year old child. Each of these body options is fully detachable and designed to minimize vehicle damage should the pedestrian detection system fail to operate, and the unit moves on an extremely low profile base unit which is invisible to vehicle systems. When combined with the unique ground truth positioning system installed at innovITS advance, the new pedestrian detection target system is said to provide a fast, accurate and repeatable testing capability for this category of automotive safety system. Read more ..
Edge of Nature
|Diego DiGhero||April 19th 2012|
New study shows that plant species living in urban backyards are closer related to each other and live shorter spans of time than plant species in the countryside near Minneapolis, Minnesota, and the cities of Halle and Saale in Germany. These cities, in the United States and Europe, harbor more plant species than rural areas. However, plant species of urban areas are closer related to each other and often share similar functions.
Consequently, urban ecosystems should be more sensitive towards environmental impacts than rural ecosystems. This was the conclusion of German and U.S. scientists, based on a field study conducted in Minneapolis (Minnesota) led by Jeannine Cavender-Bares, Associate Professor at the University of Minnesota. The new study confirms results obtained by Dr. Sonja Knapp and colleagues at the Helmholtz Centre for Environmental Research (UFZ) in a study on German flora in 2008.
The recent study compared plant diversity in private yards of the Twin Cities metropolis of Minneapolis-St. Paul in the Midwest of the United States with plant diversity at the nearby Cedar Creek Ecosystem Science Reserve, part of the Long-Term Ecological Research network supported by the U.S. National Science Foundation. Cities are growing around the world, and understanding how urbanization and urban gardening impact biodiversity and ecosystem services is increasingly important. Read more ..
The Edge of Space
|Guy Webster||April 19th 2012|
|Opportunity Rover Self-portrait, December 2011|
(credit: NASA/JPL-Caltech/Cornell/Arizona State Univversity)
More than eight years after landing on Mars for what was planned as a three-month mission, NASA’s enduring Mars Exploration Rover Opportunity is working on what essentially became a new mission last summer.
Opportunity reached a multi-year driving destination, Endeavour Crater, in August 2011. At Endeavour’s rim, it has gained access to geological deposits from an earlier period of Martian history than anything it examined during its first seven years. It also has begun an investigation of the planet’s deep interior that takes advantage of staying in one place for the Martian winter.
Opportunity landed in Eagle Crater on Mars on Jan. 25, 2004, Universal Time, three weeks after its rover twin, Spirit, landed halfway around the planet. In backyard-size Eagle Crater, Opportunity found evidence of an ancient wet environment. The mission met all its goals within the originally planned span of three months. During most of the next four years, it explored successively larger and deeper craters, adding evidence about wet and dry periods from the same era as the Eagle Crater deposits. Read more ..
Edge of Medicine
|George Foulsham||April 19th 2012|
University of California - Santa Barbara
UC Santa Barbara researchers have discovered Salmonella bacteria that are up to 100 times more capable of causing disease. Their findings may help prevent food poisoning outbreaks that continue to plague public health and the food industry.
These "hypervirulent" bugs can override vaccines and pose a risk to food safety –– and mitigation efforts are currently under way.Previous strategies to find the more dangerous bugs were unsuccessful since they behave like a "Trojan Horse" –– exposing their weapons only when causing disease –– but looking much like their less-virulent cousins in the environment.
Now that scientists know what to look for, they are developing methods to discriminate them from their less-virulent cousins. The researchers have been successful in forcing the bacteria to reveal their weapons in the laboratory –– the first step in combating them. Salmonella, found virtually everywhere, is the most common cause of foodborne illness in the United States. Read more ..
The Medical Edge
|Vanessa Pavinato||April 18th 2012|
European Society for Medical Oncology
|Small Cell Lung Cancer|
"A major goal of lung cancer treatment is to tailor the treatment to the individual," says Dr Fiona Blackhall from The Christie NHS Foundation Trust in Manchester, UK. Methods ranging from convenient blood-based molecular tests, detailed genetic analysis of tumors and functional imaging techniques have been applied in patient populations receiving a range of treatments. These findings provide impetus to continue developing a personalized medicine approach to lung cancer with the overall aim of selecting the most effective treatment for the individual."
Proteins provide clues to outcomes
An international group of researchers report promising results with a test that may identify patients likely to benefit from first-line therapy with a particular drug combination. Dr Oliver Gautschi from the Swiss Group for Clinical Cancer Research (SAKK), and collaborators from The Netherlands and the US company developing the test, conducted a retrospective analysis of two phase-II trials with a serum proteomic classifier called VeriStrat. Their aim was to evaluate the prognostic value of the test in patients with advanced non-small cell lung cancer receiving first-line treatment with bevacizumab and erlotinib. VeriStrat uses mass spectrometry to measure proteins in pre-treatment blood and assigns a result that correlates with outcome from treatment with a class of drugs known as EGFR inhibitors, which includes erlotinib and gefitinib. The test was initially developed and validated in patients who had already been treated with chemotherapy, and who then received an EGFR inhibitor in second line, Dr Gautschi explains. "We conducted this project to see if the test is also prognostic in untreated patients who received an EGFR inhibitor in the first line. Until now, this has not been clear." Read more ..
The Edge of Space
|Lynn Chandler||April 18th 2012|
|30 Doradus (credit: ESA, Hubble, STScI, NASA, et al.)|
Several million young stars are vying for attention in a new NASA Hubble Space Telescope image of a raucous stellar breeding ground in 30 Doradus, a star-forming complex located in the heart of the Tarantula nebula.
The new image comprises one of the largest mosaics ever assembled from Hubble photos and includes observations taken by Hubble’s Wide Field Camera 3 and Advanced Camera for Surveys. NASA and the Space Telescope Science Institute (STScI) in Baltimore released the image in celebration of Hubble’s 22nd anniversary.
“Hubble is the world’s premiere science instrument for making celestial observations, which allow us to unravel the mysteries of the universe,” said John Grunsfeld, associate administrator for NASA’s Science Mission Directorate in Washington and three-time Hubble repair astronaut. “In recognition of Hubble’s 22nd birthday, the new image of the 30 Doradus region, the birth place for new stars, is more than a fitting anniversary image.”
30 Doradus is the brightest star-forming region in our galactic neighborhood and home to the most massive stars ever seen. The nebula is 170,000 light-years away in the Large Magellanic Cloud, a small satellite galaxy of the Milky Way. No known star-forming region discovered to date in our galaxy is as large or as prolific as 30 Doradus. Read more ..
|Melissa Van De Werfhorst||April 18th 2012|
UCSB College of Engineerin
A new quantum mechanical-based biosensor designed by a team at University of California, Santa Barbara offers tremendous potential for detecting biomolecules at ultra-low concentrations, from instant point-of-care disease diagnostics, to detection of trace substances for forensics and security. Kaustav Banerjee, director of the Nanoelectronics Research Lab
and professor of Electrical and Computer Engineering
at UCSB, and PhD student Deblina Sarkar have proposed a methodology for beating the fundamental limits of a conventional Field-Effect-Transistor (FET) by designing a Tunnel-FET (T-FET) sensor that is faster and four orders of magnitude more sensitive. Read more ..
The Edge of Life
|Manuel Kleiner ||April 17th 2012|
|The worm Olavius algarvensis.|
In a study published in the journal Proceedings of the National Academy of Science, scientists from the Max Planck Institute for Marine Microbiology in Bremen and Greifswald University, together with colleagues from Freiburg, Italy and the USA, have revealed that a small marine worm, faced with a scarce food supply in the sandy sediments it lives in off the coast of Elba, must deal with a highly poisionous menu: this worm lives on carbon monoxide and hydrogen sulphide.
The worm, Olavius algarvensis, can thrive on these poisons thanks to millions of symbiotic bacteria that live under its skin. They use the energy from carbon monoxide and hydrogen sulphide to produce food for the worm. The symbionts do this just like plants by fixing carbon dioxide into carbohydrates but instead of using light energy from the sun, the symbionts use the energy from chemical compounds like carbon monoxide. “They do this so effectively, that the worm has lost its entire digestive system, including its mouth and gut, during the course of evolution, and feeds only through its symbionts”, explains Nicole Dubilier, Head of the Symbiosis Group at the Bremen-based Max Planck Institute. Read more ..
Race For Clean Water
|Natalie Wood-Wright||April 17th 2012|
JHU Bloomberg School of Public Health
Looking for an inexpensive and effective way to quickly improve the quality of your drinking water? According to a team of researchers from the Johns Hopkins Bloomberg School of Public Health and the Johns Hopkins School of Medicine, sunlight and a twist of lime might do the trick. Researchers found that adding lime juice to water that is treated with a solar disinfection method removed detectable levels of harmful bacteria such as Escherichia coli (E. coli) significantly faster than solar disinfection alone. The results are featured in the April 2012 issue of American Journal of Tropical Medicine and Hygiene.
"For many countries, access to clean drinking water is still a major concern. Previous studies estimate that globally, half of all hospital beds are occupied by people suffering from a water-related illness," said Kellogg Schwab, PhD, MS, senior author of the study, director of the Johns Hopkins University Global Water Program and a professor with the Bloomberg School's Department of Environmental Health Sciences. "The preliminary results of this study show solar disinfection of water combined with citrus could be effective at greatly reducing E. coli levels in just 30 minutes, a treatment time on par with boiling and other household water treatment methods. In addition, the 30 milliliters of juice per 2 liters of water amounts to about one-half Persian lime per bottle, a quantity that will likely not be prohibitively expensive or create an unpleasant flavor."
In low-income regions, solar disinfection of water is one of several household water treatment methods to effectively reduce the incidence of diarrheal illness. One method of using sunlight to disinfect water that is recommended by the United Nations Children's Fund (UNICEF) is known as SODIS (Solar water Disinfection). The SODIS method requires filling 1 or 2 liter polyethylene terephthalate (PET plastic) bottles with water and then exposing them to sunlight for at least 6 hours. Read more ..
The Edge of Medicine
|Timothy Wall||April 17th 2012|
News Bureau University of Missouri
A team of scientists from the University of Missouri created a genetically modified mouse that mimics key features of Charcot-Marie-Tooth disease, an inherited neuromuscular disease affecting approximately 150,000 people in the United States. Charcot-Marie-Tooth, or CMT, is a group of progressive disorders that affects the peripheral nervous system, the part of the nervous system that connects the brain and spinal cord to targets such as muscles. The disease largely affects the distal nerves, those running to the feet and hands, and can progress to include the legs and arms. “Wasting and weakening of the muscles occurs because the distal nerves are either dying or not functioning properly,” said Michael Garcia, study leader and associate professor of biological sciences. “The condition can be very debilitating depending on the muscles affected and the degree to which they are affected.” No cure exists for CMT, but Garcia hopes that insights gleaned from the new mouse model may aid the development of therapeutic interventions. “By learning about the basics of disease initiation and progression, perhaps we can soon test therapeutics designed to stop or reverse the pathology,” he said. Read more ..
The Edge of Health
|David Stauth||April 17th 2012|
Women are more prone to knee injuries than men, and the findings of a new study suggest this may involve more than just differences in muscular and skeletal structure – it shows that males and females also differ in the way they transmit the nerve impulses that control muscle force. Scientists at Oregon State University found that men control nerve impulses similar to individuals trained for explosive muscle usage – like those of a sprinter – while the nerve impulses of women are more similar to those of an endurance-trained athlete, like a distance runner. In particular, the research may help to explain why women tend to suffer ruptures more often than men in the anterior cruciate ligament of their knees during non-contact activities. These ACL injuries are fairly common, can be debilitating, and even when repaired can lead to osteoarthritis later in life.
More study of these differences in nervous system processing may lead to improved types of training that individuals could use to help address this issue, scientists said. “It’s clear that women move differently than men, but it’s not as obvious why that is,” said Sam Johnson, a clinical assistant professor in the OSU School of Biological and Population Health Sciences. “There are some muscular and skeletal differences between men and women, but that doesn’t explain differences in injury rates as much as you might think,” Johnson said. Read more ..
The Digital Edge
|Tracey Peake||April 17th 2012|
An innovative X-ray technique has given North Carolina State University researchers and their collaborators new insight into how organic polymers can be used in printable electronics such as transistors and solar cells. Their discoveries may lead to cheaper, more efficient printable electronic devices. Printable electronics are created by spraying or printing inks containing conductive organic molecules onto a surface. The process is fast and much less expensive than current production techniques for items like solar cells or computer and television displays. Additionally, it holds potential for amazing new applications: picture a wearable interactive display that needs no batteries.
In the solar industry, the ability to print solar cells on giant roll-to-roll printing presses – like printing a newspaper – could make the technology much more affordable and mass marketable. NC State physicists Dr. Harald Ade and Dr. Brian Collins, in collaboration with Dr. Michael Chabinyc at the University of California Santa Barbara, wanted to know why some processing steps resulted in better and more efficient devices than others. "Manufacturers know that some materials work better than others in these devices, but it's essentially still a process of trial and error," Ade says. Read more ..
The Molecular Edge
|Ellen de Graffenreid||April 17th 2012|
UNC School of Medicine
A team from the University of North Carolina at Chapel Hill demonstrates a simple, cost-effective technique for three-dimensional RNA structure prediction that will help scientists understand the structures, and ultimately the functions, of the RNA molecules that dictate almost every aspect of human cell behavior. When cell behavior goes wrong, diseases – including cancer and metabolic disorders – can be the result. Over the past five decades, scientists have described more than 80,000 protein structures, most of which are now publicly available and provide important information to medical researchers searching for targets for drug therapy.
However, a similar effort to catalogue RNA structures has mapped only a few hundred RNA molecules. As a result, the potential of RNA molecules has just barely been developed as targets for new therapeutics. "To effectively target these molecules, researchers often need a three-dimensional picture of what they look like," says Nikolay Dokholyan, PhD.
"With Dr. Kevin Weeks' lab, we have developed a way to create a three-dimensional map of complex RNAs that are not amenable to study through other methods. It builds on information from a routine laboratory experiment, used in the past to evaluate RNA models from a qualitative standpoint. Our team has created a sophisticated quantitative model that uses this simple information to predict structures for large, complex RNA molecules, which have previously been beyond the reach of modeling techniques," he adds. Read more ..
Energy vs Environment
|Mike Williams||April 17th 2012|
Researchers at Rice University and Penn State University have discovered that adding a dash of boron to carbon while creating nanotubes turns them into solid, spongy, reusable blocks that have an astounding ability to absorb oil spilled in water. That’s one of a range of potential innovations for the material created in a single step. The team found for the first time that boron puts kinks and elbows into the nanotubes as they grow and promotes the formation of covalent bonds, which give the sponges their robust qualities.
The researchers, who collaborated with peers in labs around the nation and in Spain, Belgium and Japan, revealed their discovery in Nature’s Scientific Reports. Lead a uthor Daniel Hashim, a graduate student in the Rice lab of materials scientist Pulickel Ajayan, said the blocks are both superhydrophobic (they hate water, and float really well) and oleophilic (they love oil). The nanosponges, which are more than 99 percent air, also conduct electricity and can easily be manipulated with magnets. To demonstrate, Hashim dropped the sponge into a dish of water with used motor oil floating on top. The sponge soaked it up. He then put a match to the material, burned off the oil and returned the sponge to the water to absorb more. The robust sponge can be used repeatedly and stands up to abuse; he said a sample remained elastic after about 10,000 compressions in the lab. The sponge can also store the oil for later retrieval, he said. Read more ..
The Way We Are
|Matt Shipman ||April 17th 2012|
North Carolina State University
In order to accurately identify skulls as male or female, forensic anthropologists need to have a good understanding of how the characteristics of male and female skulls differ between populations. A new study from North Carolina State University shows that these differences can be significant, even between populations that are geographically close to one another.
The researchers looked at the skulls of 27 women and 28 men who died in Lisbon, Portugal, between 1880 and 1975. They also evaluated the skulls of 40 women and 39 men who died between 1895 and 1903 in the rural area of Coimbra, just over 120 miles north of Lisbon.
The researchers found significant variation between female skulls from Lisbon and those from Coimbra. “The differences were in the shape of the skull, not the size,” says Dr. Ann Ross, professor of anthropology at NC State and co-author of a paper describing the study. “This indicates that the variation is due to genetic differences, rather than differences of diet or nutrition.” The researchers found little difference between the male skulls.
Specifically, the researchers found that the female skulls from Lisbon exhibited greater intraorbital distance than the skulls of Coimbra females. In other words, the women from Lisbon had broader noses and eyes that were spaced further apart.
This difference in craniofacial characteristics may stem from an influx of immigrants into Lisbon, which is a port city, Ross says. However, it may also be a result of preferential mate selection—meaning Lisbon men were finding mates abroad, or were more attracted to women with those facial features. Read more ..
The Edge of Space
|Francis Reddy||April 17th 2012|
|Commet Garradd, outbound (credit: NASA; Swift; D. Bodewits (UMD);|
S. Immler (GSFC); and DSS/STScI/AURA)
An outbound comet that provided a nice show for skywatchers late last year is the target of an ongoing investigation by NASA’s Swift satellite. Formally designated C/2009 P1 (Garradd), the unusually dust-rich comet provides a novel opportunity to characterize how cometary activity changes at ever greater distance from the sun.
A comet is a clump of frozen gases mixed with dust. These “dirty snowballs” cast off gas and dust whenever they venture near the sun. What powers this activity is frozen water transforming from solid ice to gas, a process called sublimation. Jets powered by ice sublimation release dust, which reflects sunlight and brightens the comet. Typically, a comet’s water content remains frozen until it comes within about three times Earth’s distance to the sun, or 3 astronomical units (AU), so astronomers regard this as the solar system’s “snow line.”
“Comet Garradd was producing lots of dust and gas well before it reached the snow line, which tells us that the activity was powered by something other than water ice,” said Dennis Bodewits, an assistant research scientist at UMCP and the study’s lead investigator. “We plan to use Swift’s unique capabilities to monitor Garradd as it moves beyond the snow line, where few comets are studied.” Read more ..
The Edge of Nature
|Deborah Williams-Hedges||April 16th 2012|
California Institute of Technology
|Assorted nematodes (credit: CalTech)|
All animals seem to have ways of exchanging information—monkeys vocalize complex messages, ants create scent trails to food, and fireflies light up their abdomens to attract mates. Yet, despite the fact that nematodes, or roundworms, are among the most abundant animals on the planet, little is known about the way they network. Now, research led by California Institute of Technology (Caltech) biologists has shown that a wide range of nematodes communicate using a recently discovered class of chemical cues: small-molecule pheromones.
A paper outlining their studies—which were a collaborative effort with the laboratory of Frank C. Schroeder, assistant scientist at the Boyce Thompson Institute for Plant Research (BTI) of Cornell University—was published online April 12 in Current Biology. Read more ..
The Medical Edge
New research findings suggest the key to finding a whole new variety of antibiotics to treat drug-resistant infections may lie with the resident bacteria in one of the most isolated caves in the world.
The U.S. scientists who conducted the study say bacteria collected from Lechuguilla Cave in the state of New Mexico appear to possess an innate resistance to antibiotics, despite never having been exposed to any human sources. Some of the bacteria had a pre-existing defense against as many as 14 different antibiotics. In all, the scientists say the cave-dwelling organisms showed a naturally-developed resistance to virtually every antibiotic currently used to treat bacterial infections.
While this may sound like bad news, the researchers explain that finding isolated, drug-resistant bacteria actually is a good thing. They say it suggests there are many types of previously unknown, naturally-occurring antibiotics in the environment that can be developed for doctors to use against currently untreatable infections.
First discovered 70 years ago, antibiotics are only effective against disease caused by bacterial infection. However, decades of widespread overuse, especially in agriculture industries, and via over-prescription by doctors, has made increasing types of disease-causing bacteria - so-called superbugs - immune to antibiotics. There is increasing concern among scientists and medical experts that current antibiotic treatments could become completely ineffective against bacterial infections, which would be catastrophic for millions of people around the world suffering from diseases such as malaria. Read more ..
The Edge Of Nature
|Zulima Palacio||April 15th 2012|
Since the mid 1990s, a type of virus known as a ranavirus has been taking a devastating toll on reptiles and amphibians -- especially turtles, frogs, toads and salamanders -- in more than 20 states across the U.S. Hundreds of thousands of these animals have died from the lethal virus and the disease continues to spread. Scientists are stepping up their efforts to better understand and combat the pathogen. Tracking the virus A few years ago, Scott Farnsworth, a graduate student at Towson University in Maryland, was sent to a wooded park in Maryland to relocate box turtles safely away from a new highway. Farnsworth and his team tagged 100 turtles with radio transmitters. But then the reptiles started turning up dead.
And not just turtles. They began seeing massive die-offs of toads, young frogs called tadpoles and salamanders. Lab analyses showed the culprit was the ranavirus, a class of viruses that mostly infect cold blooded animals.
“It’s pretty quick. We can go from seeing no outer signs," he explained. "To having complete mortality for all of the ones in the pond within a few days.” While amphibians die within hours of infection, box turtles can survive as long as a month. A lab test showed the animal died struggling to breathe. Ranavirus often infects amphibians during their egg and juvenile stages, leaving them unable to swim. But it affects only adult turtles. “It could send them on a glide path towards extinction,” said Farnsworth. Farnsworth carefully checks for signs of life at a pond where all the animals died last year. Read more ..
The Edge of Technology
|Matt Hodson||April 14th 2012|
There are twice as many emperor penguins in Antarctica than was previously thought, according to a new study released today by an international team of researchers using high-resolution satellite mapping technology. This first-ever count of an entire species from space provides an important benchmark for monitoring the impact of environmental change on the population of this iconic bird.
Scientists from the University of Minnesota Polar Geospatial Center co-authored the research with partners from the British Antarctic Survey. The research is published today in the journal PLoS ONE. In the journal, the scientists describe how they used Very High Resolution (VHR) satellite images to estimate the number of penguins at each colony around the coastline of Antarctica. Using a technique known as pan-sharpening to increase the resolution of the satellite imagery, the science teams were able to differentiate between birds, ice, shadow and penguin poo (guano).
They then used ground counts and aerial photography to calibrate the analysis. These birds breed in areas that are very difficult to study because they are remote and often inaccessible with temperatures as low as -58°F (-50°C). Lead author and geographer Peter Fretwell at the British Antarctic Survey (BAS), which is funded by the UK's Natural Environment Research Council, said the research findings are groundbreaking.
"We are delighted to be able to locate and identify such a large number of emperor penguins," Fretwell said. "We counted 595,000 birds, which is almost double the previous estimates of 270,000 to 350,000 birds. This is the first comprehensive census of a species taken from space." On the ice, emperor penguins with their black and white plumage stand out against the snow and colonies are clearly visible on satellite imagery. This allowed the team to analyze 44 emperor penguin colonies around the coast of Antarctica, with seven previously unknown. Read more ..
The Computer Edge
|Larry Hardesty||April 14th 2012|
Computer chips have stopped getting faster. In order to keep increasing chips’ computational power at the rate to which we’ve grown accustomed, chipmakers are instead giving them additional “cores,” or processing units.
Today, a typical chip might have six or eight cores, all communicating with each other over a single bundle of wires, called a bus. With a bus, however, only one pair of cores can talk at a time, which would be a serious limitation in chips with hundreds or even thousands of cores, which many electrical engineers envision as the future of computing.
Li-Shiuan Peh, an associate professor of electrical engineering and computer science at MIT, wants cores to communicate the same way computers hooked to the Internet do: by bundling the information they transmit into “packets.” Each core would have its own router, which could send a packet down any of several paths, depending on the condition of the network as a whole.
At the Design Automation Conference in June, Peh and her colleagues will present a paper she describes as “summarizing 10 years of research” on such “networks on chip.” Not only do the researchers establish theoretical limits on the efficiency of packet-switched on-chip communication networks, but they also present measurements performed on a test chip in which they came very close to reaching several of those limits. Read more ..
The Edge of Space
|Louise Lerner||April 14th 2012|
Argonne National Laboratory
The early days of our solar system might look quite different than previously thought, according to research at the U.S. Department of Energy’s (DOE) Argonne National Laboratory published in Science. The study used more sensitive instruments to find a different half-life for samarium, one of the isotopes used to chart the evolution of the solar system.“It shrinks the chronology of early events in the solar system, like the formation of planets, into a shorter time span,” said Argonne physicist Michael Paul. “It also means some of the oldest rocks on Earth would have formed even earlier — as early as 120 million years after the solar system formed, in one case of Greenland rocks.”According to current theory, everything in our solar system formed from star dust several billion years ago. Some of this dust was formed in giant supernovae explosions which supplied most of our heavy elements. One of these is the isotope samarium-146.Samarium-146, or Sm-146, is unstable and occasionally emits a particle, which changes the atom into a different element. Using the same technique as radiocarbon dating, scientists can calculate how long it’s been since the Sm-146 was created.
Because Sm-146 decays extremely slowly—on the order of millions of years—many models use it to help determine the age of the solar system.The number of years it takes for an isotope to decrease by half is called its half-life. Since Sm-146 emits particles so rarely, it takes a sophisticated instrument to measure this half-life.The Argonne Tandem Linac Accelerator System, or ATLAS, is a DOE national user facility for the study of nuclear structure and astrophysics, and is just such an instrument. “It’s easy for the ATLAS, used as a mass spectrometer, to pick out one Sm-146 atom in tens of billions of atoms,” said physicist Richard Pardo, who manages the facility and participated in the study. Read more ..
The Edge of Space
|Kate Ramsayer||April 13th 2012|
American Geophysical Union
|Uranus’s Auroras (credit: Laurent Lamy)|
For the first time, scientists have captured images of auroras above the giant ice planet Uranus, finding further evidence of just how peculiar a world that distant planet is. Detected by means of carefully scheduled observations from the Hubble Space Telescope, the newly witnessed Uranian light show consisted of short-lived, faint, glowing dots—a world of difference from the colorful curtains of light that often ring Earth’s poles.
In the new observations, which are the first to glimpse the Uranian aurora with an Earth-based telescope, the researchers detected the luminous spots twice on the day side of Uranus—the side that’s visible from Hubble. Previously, the distant aurora had only been measured using instruments on a passing spacecraft. Unlike auroras on Earth, which can turn the sky greens and purples for hours, the newly detected auroras on Uranus appeared to only last a couple minutes.
In general, auroras are a feature of the magnetosphere, the area surrounding a planet that is controlled by its magnetic field and shaped by the solar wind, a steady flow of charged particles emanating from the sun. Auroras are produced in the atmosphere as charged solar wind particles accelerate in the magnetosphere and are guided by the magnetic field close to the magnetic poles—that’s why the Earthly auroras are found around high latitudes. Read more ..
|Daniel Stolte||April 12th 2012|
Graphite, more commonly known as pencil lead, could become the next big thing in the quest for smaller and less power-hungry electronics.
Resembling chicken wire on a nano scale, graphene – single sheets of graphite – is only one atom thick, making it the world's thinnest material. Two million graphene sheets stacked up would not be as thick as a credit card.
The tricky part physicists have yet to figure out how to control the flow of electrons through the material, a necessary prerequisite for putting it to work in any type of electronic circuit. Graphene behaves very different than silicon, the material currently used in semiconductors.
Last year, a research team led by University of Arizona physicists cleared the first hurdle by identifying boron nitride, a structurally identical but non-conducting material, as a suitable mounting surface for single-atom sheets of graphene. The team also showed that in addition to providing mechanical support, boron nitride improves the electronic properties of graphene by smoothening out fluctuations in the electronic charges. Read more ..
The Edge of Space
|Stuart Wolpert||April 12th 2012|
|Image from MOSFIRE showing colliding galaxies|
(credit: Ian S. McLean/W.M. Keck Observatory)
A new scientific instrument, a “time machine” of sorts, built by UCLA astronomers and colleagues, will allow scientists to study the earliest galaxies in the universe for the first time The five-ton instrument, the most advanced and sophisticated of its kind in the world, goes by the name MOSFIRE (Multi-Object Spectrometer for Infra-Red Exploration) and has been installed in the Keck I Telescope at the W.M. Keck Observatory atop Mauna Kea in Hawaii. MOSFIRE gathers light in infrared wavelengths—invisible to the human eye—allowing it to penetrate cosmic dust and see distant objects whose light has been redshifted to the infrared by the expansion of the universe.
“The instrument was designed to study the most distant, faintest galaxies,” said UCLA physics and astronomy professor Ian S. McLean, project leader on MOSFIRE and director of UCLA’s Infrared Laboratory for Astrophysics. “When we look at the most distant galaxies, we see them not as they are now but as they were when the light left them that is just now arriving here. Some of the galaxies that we are studying were formed some 10 billion years ago—only a few billion years after the Big Bang. We are looking back in time to the era of the formation of some of the very first galaxies, which are small and very faint. That is an era that we need to study if we are going to understand the large-scale structure of the universe.” Read more ..
The Metal's Edge
Earth is clingy when it comes to copper. A new Rice University study recently published in the journal Science finds that nature conspires at scales both large and small -- from the realms of tectonic plates down to molecular bonds -- to keep most of Earth's copper buried dozens of miles below ground. "Everything throughout history shows us that Earth does not want to give up its copper to the continental crust," said Rice geochemist Cin-Ty Lee, the lead author of the study. "Both the building blocks for continents and the continental crust itself, dating back as much as 3 billion years, are highly depleted in copper."
Finding copper is more than an academic exercise. With global demand for electronics growing rapidly, some studies have estimated the world's demand for copper could exceed supply in as little as six years. The new study could help, because it suggests where undiscovered caches of copper might lie.
But the copper clues were just a happy accident. "We didn't go into this looking for copper," Lee said. "We were originally interested in how continents form and more specifically in the oxidation state of volcanoes." Read more ..
The Edge of Space
|Daniel Cochlin||April 12th 2012|
Writing in Nature, the team of researchers used new techniques which allowed them to look into the atmospheres of distant, dying stars.
The team, lead by Barnaby Norris from the University of Sydney in Australia, includes scientists from the Universities of Manchester, Paris-Diderot, Oxford and Macquarie University, New South Wales. They used the Very Large Telescope in Chile, operated by the European Southern Observatory.
At the resolution used by the scientists, one could, from the UK, distinguish the two headlights on a car in Australia. This extreme resolution made it possible to resolve the red giant stars, and to see winds of gas and dust coming off the star.
Stars like the Sun end their lives with a 'superwind', 100 million times stronger than the solar wind. This wind occurs over a period of 10,000 years, and removes as much as half the mass of the star. At the end, only a dying and fading remnant of the star will be left. The Sun will begin to throw out these gases in around five billion years. Read more ..
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