writes "Brain cells that multiply to help birds sing their best during breeding season are known to die back naturally later in the year. For the first time researchers have described the series of events that cues new neuron growth each spring, and it all appears to start with a signal from the expiring cells the previous fall that primes the brain to start producing stem cells.
If scientists can further tap into the process and understand how those signals work, it might lead to ways to exploit these signals and encourage replacement of cells in human brains that have lost neurons naturally because of aging, severe depression or Alzheimer’s disease, said Tracy Larson, a University of Washington doctoral student in biology. She’s lead author of a paper in the Sept. 23 Journal of Neuroscience on brain cell birth that follows natural brain cell death.
Neuroscientists have long known that new neurons are generated in the adult brains of many animals, but the birth of new neurons – or neurogenesis – appears to be limited in mammals and humans, especially where new neurons are generated after there’s been a blow to the head, stroke or some other physical loss of brain cells, Larson said. That process, referred to as “regenerative” neurogenesis, has been studied in mammals since the 1990s. This is the first published study to examine the brain’s ability to replace cells that have been lost naturally, Larson said."
writes "Using modern statistical tools, a new study led by the University of Washington and the United Nations finds that world population is likely to keep growing throughout the 21st century. The number of people on Earth is likely to reach 11 billion by 2100, the study concludes, about 2 billion higher than widely cited previous estimates. The paper published online Sept. 18 in the journal Science includes the most up-to-date numbers for future world population, and describes a new method for creating such estimates.
“The consensus over the past 20 years or so was that world population, which is currently around 7 billion, would go up to 9 billion and level off or probably decline,” said corresponding author Adrian Raftery, a UW professor of statistics and of sociology. “We found there’s a 70 percent probability the world population will not stabilize this century. Population, which had sort of fallen off the world’s agenda, remains a very important issue.”
The paper explains the most recent United Nations population data released in July. This is the first U.N. population report to use modern statistics, known as Bayesian statistics, that combines all available information to generate better predictions.
Most of the anticipated growth is in Africa, where population is projected to quadruple from around 1 billion today to 4 billion by the end of the century. The main reason is that birth rates in sub-Saharan Africa have not been going down as fast as had been expected. There is an 80 percent chance that the population in Africa at the end of the century will be between 3.5 billion and 5.1 billion people."Link to Original Source
writes "The number of California blue whales has rebounded to near historical levels, according to new research by the University of Washington, and while the number of blue whales struck by ships is likely above allowable U.S. limits, such strikes do not immediately threaten that recovery. This is the only population of blue whales known to have recovered from whaling – blue whales as a species having been hunted nearly to extinction.
Blue whales – nearly 100 feet in length and weighing 190 tons as adults – are the largest animals on Earth and the heaviest ever, weighing more than twice as much as the largest known dinosaur, the Argentinosaurus. They are an icon of the conservation movement and many people want to minimize harm to them, according to Trevor Branch, UW assistant professor of aquatic and fishery sciences.
“The recovery of California blue whales from whaling demonstrates the ability of blue whale populations to rebuild under careful management and conservation measures,” said Cole Monnahan, a UW doctoral student in quantitative ecology and resource management and lead author of a paper on the subject posted online Sept. 5 by the journal Marine Mammal Science. Branch and André Punt, a UW professor of aquatic and fisheries sciences, are co-authors.
California blue whales, most visible while feeding 20 to 30 miles off the California coast, range fom the equator to the Gulf of Alaska. Today they number about 2,200, according to monitoring by other research groups, which is likely about 97 percent of the historical levels."Link to Original Source
writes "Scientists have developed what they believe is the thinnest-possible semiconductor, a new class of nanoscale materials made in sheets only three atoms thick. The University of Washington researchers have demonstrated that two of these single-layer semiconductor materials can be connected in an atomically seamless fashion known as a heterojunction. This result could be the basis for next-generation flexible and transparent computing, better light-emitting diodes, or LEDs, and solar technologies.
“Heterojunctions are fundamental elements of electronic and photonic devices,” said senior author Xiaodong Xu, a UW assistant professor of materials science and engineering and of physics. “Our experimental demonstration of such junctions between two-dimensional materials should enable new kinds of transistors, LEDs, nanolasers, and solar cells to be developed for highly integrated electronic and optical circuits within a single atomic plane.”
The research was published online this week in Nature Materials. The researchers discovered that two flat semiconductor materials can be connected edge-to-edge with crystalline perfection. They worked with two single-layer, or monolayer, materials – molybdenum diselenide and tungsten diselenide – that have very similar structures, which was key to creating the composite two-dimensional semiconductor."Link to Original Source
writes "Jaundice in newborns is one of the last things a parent wants to deal with, but it’s unfortunately a common condition in babies less than a week old. Skin that turns yellow can be a sure sign that a newborn is jaundiced and isn’t adequately eliminating the chemical bilirubin. But that discoloration is sometimes hard to see, and severe jaundice left untreated can harm a baby. University of Washington engineers and physicians have developed a smartphone application that checks for jaundice in newborns and can deliver results to parents and pediatricians within minutes. It could serve as a screening tool to determine whether a baby needs a blood test – the gold standard for detecting high levels of bilirubin.
“Virtually every baby gets jaundiced, and we’re sending them home from the hospital even before bilirubin levels reach their peak,” said James Taylor, a UW professor of pediatrics and medical director of the newborn nursery at UW Medical Center. “This smartphone test is really for babies in the first few days after they go home. A parent or health care provider can get an accurate picture of bilirubin to bridge the gap after leaving the hospital.”
The research team will present its results at the Association for Computing Machinery’s International Joint Conference on Pervasive and Ubiquitous Computing in September in Seattle."Link to Original Source
writes "Following rapid warming in the late 20th century, this century has so far seen surprisingly little increase in the average temperature at the Earth’s surface. More than a dozen theories have now been proposed for the so-called global warming hiatus, ranging from air pollution to volcanoes to sunspots. New research from the University of Washington shows the heat absent from the surface is plunging deep in the north and south Atlantic Ocean, and is part of a naturally occurring cycle. The study is published Aug. 22 in Science.
Subsurface ocean warming explains why global average air temperatures have flatlined since 1999, despite greenhouse gases trapping more solar heat at the Earth’s surface. “Every week there’s a new explanation of the hiatus,” said corresponding author Ka-Kit Tung, a UW professor of applied mathematics and adjunct faculty member in atmospheric sciences. “Many of the earlier papers had necessarily focused on symptoms at the surface of the Earth, where we see many different and related phenomena. We looked at observations in the ocean to try to find the underlying cause.”
What they found is that a slow-moving current in the Atlantic, which carries heat between the two poles, sped up earlier this century to draw heat down almost a mile (1,500 meters). Most previous studies focused on shorter-term variability or particles that could block incoming sunlight, but they could not explain the massive amount of heat missing for more than a decade."Link to Original Source
writes "Imagine a world in which your wristwatch or other wearable device communicates directly with your online profiles, storing information about your daily activities where you can best access it – all without requiring batteries. Or, battery-free sensors embedded around your home that could track minute-by-minute temperature changes and send that information to your thermostat to help conserve energy. This not-so-distant “Internet of Things” reality would extend connectivity to perhaps billions of devices. Sensors could be embedded in everyday objects to help monitor and track everything from the structural safety of bridges to the health of your heart. But having a way to cheaply power and connect these devices to the Internet has kept this from taking off.
Now, University of Washington engineers have designed a new communication system that uses radio frequency signals as a power source and reuses existing Wi-Fi infrastructure to provide Internet connectivity to these devices. Called Wi-Fi backscatter, this technology is the first that can connect battery-free devices to Wi-Fi infrastructure. The researchers will publish their results at the Association for Computing Machinery’s Special Interest Group on Data Communication‘s annual conference this month in Chicago. The team also plans to start a company based on the technology."Link to Original Source
writes "Soon, protection from HIV infection could be as simple as inserting a medicated, disappearing fabric minutes before having sex. University of Washington bioengineers have discovered a potentially faster way to deliver a topical drug that protects women from contracting HIV. Their method spins the drug into silk-like fibers that quickly dissolve when in contact with moisture, releasing higher doses of the drug than possible with other topical materials such as gels or creams.
“This could offer women a potentially more effective, discreet way to protect themselves from HIV infection by inserting the drug-loaded materials into the vagina before sex,” said Cameron Ball, a UW doctoral student in bioengineering and lead author on a paper in the August issue of Antimicrobial Agents and Chemotherapy."Link to Original Source
writes "As the climate warms and sea ice retreats, the North is changing. An ice-covered expanse now has a season of increasingly open water that is predicted to extend across the whole Arctic Ocean before the middle of this century. Storms thus have the potential to create Arctic swell – huge waves that could add a new and unpredictable element to the region. A University of Washington researcher made the first study of waves in the middle of the Arctic Ocean and detected house-sized waves during a September 2012 storm. The results were recently published in Geophysical Research Letters.
“As the Arctic is melting, it’s a pretty simple prediction that the additional open water should make waves,” said lead author Jim Thomson, an oceanographer with the UW Applied Physics Laboratory. His data show that winds in mid-September 2012 created waves of 5 meters (16 feet) high during the peak of the storm. The research also traces the sources of those big waves: high winds, which have always howled through the Arctic, combined with the new reality of open water in summer."Link to Original Source
writes "There is no cure for Alzheimer’s disease and other forms of dementia, but the research community is one step closer to finding treatment. University of Washington bioengineers have a designed a peptide structure that can stop the harmful changes of the body’s normal proteins into a state that’s linked to widespread diseases such as Alzheimer’s, Parkinson’s, heart disease, Type 2 diabetes and Lou Gehrig’s disease. The synthetic molecule blocks these proteins as they shift from their normal state into an abnormally folded form by targeting a toxic intermediate phase. The discovery of a protein blocker could lead to ways to diagnose and even treat a large swath of diseases that are hard to pin down and rarely have a cure.
“If you can truly catch and neutralize the toxic version of these proteins, then you hopefully never get any further damage in the body,” said senior author Valerie Daggett, a UW professor of bioengineering. “What’s critical with this and what has never been done before is that a single peptide sequence will work against the toxic versions of a number of different amyloid proteins and peptides, regardless of their amino acid sequence or the normal 3-D structures.”"Link to Original Source
writes "Philadelphia's NPR affiliate, WHYY FM, reported today on their Newsworks program that a research team at the University of Pennsylvania have released their preliminary findings on the use of graphene as a conductor in the next generation of computer chips. "It's very, very strong mechanically, and it is an excellent electronic material that might be used in future computer chips," said Charlie Johnson, a professor of physics and astronomy at the University of Pennsylvania. From the article: Future graphene transistors, Johnson said, are likely to be only tens of atoms across."
writes "The disastrous March 22 landslide that killed 43 people in the rural Washington state community of Oso involved the "remobilization" of a 2006 landslide on the same hillside, a new federally sponsored geological study concludes.
The research indicates the landslide, the deadliest in U.S. history, happened in two major stages. The first stage remobilized the 2006 slide, including part of an adjacent forested slope from an ancient slide, and was made up largely or entirely of deposits from previous landslides. The first stage ultimately moved more than six-tenths of a mile across the north fork of the Stillaguamish River and caused nearly all the destruction in the Steelhead Haven neighborhood. The second stage started several minutes later and consisted of ancient landslide and glacial deposits. That material moved into the space vacated by the first stage and moved rapidly until it reached the trailing edge of the first stage, the study found.
The report, released Tuesday on the four-month anniversary of the slide, details an investigation by a team from the Geotechnical Extreme Events Reconnaissance Association, or GEER. The scientists and engineers determined that intense rainfall in the three weeks before the slide likely was a major issue, but factors such as altered groundwater migration, weakened soil consistency because of previous landslides and changes in hillside stresses played key roles.
"Perhaps the most striking finding is that, while the Oso landslide was a rare geologic occurrence, it was not extraordinary," said Joseph Wartman, a University of Washington associate professor of civil and environmental engineering and a team leader for the study.
"We observed several other older but very similar long-runout landslides in the surrounding Stillaguamish River Valley. This tells us these may be prevalent in this setting over long time frames. Even the apparent trigger of the event – several weeks of intense rainfall – was not truly exceptional for the region," Wartman said."Link to Original Source
writes ""Infants can tell the difference between sounds of all languages until about 8 months of age, when their brains start to focus only on sounds they hear around them. It’s been unclear how this transition occurs, but social interactions and caregivers’ use of exaggerated “parentese” style of speech seem to help.
New University of Washington research in 7- and 11-month-old infants shows that speech sounds stimulate areas of the brain that coordinate and plan motor movements for speech. The study, published July 14 in the Proceedings of the National Academy of Sciences, suggests that baby brains start laying down the groundwork of how to form words long before they actually begin to speak, and this may affect the developmental transition.
“Most babies babble by 7 months, but don’t utter their first words until after their first birthdays,” said lead author Patricia Kuhl, who is the co-director of the UW’s Institute for Learning and Brain Sciences. “Finding activation in motor areas of the brain when infants are simply listening is significant, because it means the baby brain is engaged in trying to talk back right from the start and suggests that 7-month-olds’ brains are already trying to figure out how to make the right movements that will produce words.”
Kuhl and her research team believe this practice at motor planning contributes to the transition when infants become more sensitive to their native language.""Link to Original Source
writes "Car and truck exhaust fumes that foul the air for humans also cause problems for pollinators. In new research on how pollinators find flowers when background odors are strong, University of Washington and University of Arizona researchers found that both natural plant odors and human sources of pollution can conceal the scent of sought-after flowers.
When the calories from one feeding of a flower gets you only 15 minutes of flight, as is the case with the tobacco hornworn moth studied, being misled costs a pollinator energy and time.
“Local vegetation can mask the scent of flowers because the background scents activate the same moth olfactory channels as floral scents,” according to Jeffrey Riffell, UW assistant professor of biology. “Plus the chemicals in these scents are similar to those emitted from exhaust engines and we found that pollutant concentrations equivalent to urban environments can decrease the ability of pollinators to find flowers.”
Riffell is lead author of a paper on the subject in the June 27 issue of Science."Link to Original Source
writes "The West Antarctic Ice Sheet, which holds enough water to raise global seas by several feet, is thinning. Scientists have been warning of its collapse, based on theories, but with few firm predictions or timelines.
University of Washington researchers used detailed topography maps and computer modeling to show that the collapse appears to have already begun. The fast-moving Thwaites Glacier will likely disappear in a matter of centuries, researchers say, raising sea level by nearly 2 feet. That glacier also acts as a linchpin on the rest of the ice sheet, which contains enough ice to cause another 10 to 13 feet (3 to 4 meters) of global sea level rise. The study is published May 16 in Science.
“There’s been a lot of speculation about the stability of marine ice sheets, and many scientists suspected that this kind of behavior is under way,” said Ian Joughin, a glaciologist at the UW’s Applied Physics Laboratory. “This study provides a more quantitative idea of the rates at which the collapse could take place.”"Link to Original Source