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Nokia 515 review: Time machine

GSMArena team, 20 November 2013. They certainly don't make them like that anymore. Been a while though and we're not sure if this is a compliment. It's been long enough since speed dial was invented. And T9 predictive text. Or color displays. So, what'...
Science

Impacts of plant invasions become less robust over time: Invasive plants are more likely to be replaced by other ‘invasives’

Nov. 20, 2013 — Among the most impressive ecological findings of the past 25 years is the ability of invasive plants to radically change ecosystem function. Yet few if any studies have examined whether ecosystem impacts of invasions persist over time, and what that means for plant communities and ecosystem restoration.

UC Santa Barbara's Carla D'Antonio, Schuyler Professor of Environmental Studies, has conducted one of the only long-term studies of plant invader impacts that spans two decades. Returning to the same grass-invaded field sites in Hawaii Volcanoes National Park that she used in her 1990-1995 studies, D'Antonio, along with postdoctoral scholar Stephanie Yelenik, gathered new data that shed light on mechanisms regulating exotic plant dominance and community change through invasion. The findings are published online today in Nature.

"We were able to take advantage of detailed studies I and others had conducted in the 1990s. We permanently marked sites we had set up and were able to go back and gain insight into how plant invasions changed over time without management," said D'Antonio, who also is a professor in the Department of Ecology, Evolution and Marine Biology. "Such studies are important because managers have little money to control invasive species or to study how impacts might change without management."

"Non-native plants can have very large impacts on ecosystem functioning -- including altering groundwater, soil salinity or pH and pollination syndromes," said lead author Yelenik, who earned her doctorate from UCSB's Department of Ecology, Evolution and Marine Biology and now works for the U.S. Geological Survey's Pacific Island Ecosystems Research Center on the island of Hawaii.

When D'Antonio and Yelenik revisited the study sites, they noticed that the invasive exotic perennial grasses (primarily an African invader called Melinis minutiflora) were dying, so they decided to repeat measures of nutrient cycling and plant community change. They found that the grasses' self-reinforcing effects on soil nutrients had disappeared and the percentage of invader coverage had declined.

Data showed that in the past 17 years, nitrogen mineralization rates at the sites dominated by the exotic grasses declined by half, returning them to pre-invasion levels. Nitrogen mineralization is the process by which organic nitrogen is converted to plant-available inorganic forms.

"Measuring mineralization the way we do is extremely time-consuming and expensive, so we did it in snapshots of time (mid-1990s versus 2010-2012)," Yelenik explained. "This is less than ideal because differences between the two study periods could be due to differences in rainfall."

To eliminate rainfall as a factor, the researchers examined long-term rainfall data for the region to determine if a relationship exists between nitrogen mineralization and rainfall during the study years. The data showed that rainfall during the two study periods was similar. In addition, rainfall did not correlate with differences in mineralization between time points. A mineralization assay in the lab, where moisture was kept constant, showed similar patterns to the researchers' most recent field data, gathered in 2011 and 2012. Taken together, these results suggest that nitrogen mineralization variations between the 1990s and recent years were not due to differences in rainfall.

While the study demonstrates that ecosystem impacts and feedbacks shift over time, it also indicates that this may not necessarily help native species' recovery. Yelenik and D'Antonio conducted a large outplanting experiment to test how a suite of native and exotic woody species responded to shifting ecosystem impacts. They added nitrogen fertilizer to mimic earlier stages of Melinis invasion and reduced Melinis competition to mimic patches during late invasion.

Similar responses occurred in five of the seven outplanted species: Growth rates and survivorship increased due to reduced competition from the exotic grasses as well as nitrogen additions. This indicates that the changing impacts of the grass over time do not alter the seedlings' ability to grow in the ecosystem.

Two nitrogen-fixing trees were exceptions: the native Hawaiian tree Acacia koa and the exotic tree Morella faya (from the Canary Islands but invading Hawaii today). These species did much better in later Melinis invasion conditions, and Morella faya did particularly well.

"The non-native Morella faya did a lot better for various reasons, but primarily because it has a faster growth rate," Yelenik said. "Plus in our sites it is bird-dispersed, which means it gets around and is, in fact, moving into the sites at a frightening rate. By contrast, the native Acacia did reasonably well in the experiment, but it just does not have as robust a growth rate as Morella. It is a very slow disperser and sparse in the region so we are not seeing it entering the sites on its own."

An important lesson here is that even if plant invasions can slow down on their own given enough time, native species may need further assistance in order to make a comeback, the researchers said. Other invaders may be poised to take advantage of reduced competition from the original invader.

"Knowing the mechanisms of how and why invasions alter ecosystems is insightful for predicting what will happen, but without further management we may not get native species back," Yelenik said. "When we see non-native species dying back and getting patchy, that may be the time to plant native species. It might turn out to be the most cost-effective way to get an ecosystem back to a more desirable state."

Science
Science

Skeletal remains of 24,000-year-old boy raise new questions about first Americans

Nov. 20, 2013 — Results from a DNA study of a young boy's skeletal remains believed to be 24,000 years old could turn the archaeological world upside down -- it's been demonstrated that nearly 30 percent of modern Native American's ancestry came from this youngster's gene pool, suggesting First Americans came directly from Siberia, according to a research team that includes a Texas A&M University professor.

Kelly Graf, assistant professor in the Center for the Study of First Americans and Department of Anthropology at Texas A&M, is part of an international team spearheaded by Eske Willerslev and Maanasa Raghaven from the Centre for GeoGenetics at the University of Copenhagen, Denmark and additional researchers from Sweden, Russia, United Kingdom, University of Chicago and University of California-Berkeley. Their work, funded by the Danish National Science Foundation, Lundbeck Foundation, and the National Science Foundation, is published in the current issue of Nature magazine.

Graf and Willerslev conceived the project and traveled to the Hermitage State Museum in St. Petersburg, Russia, where the remains are now housed to collect samples for ancient DNA. The skeleton was first discovered in the late 1920s near the village of Mal'ta in south-central Siberia, and since then it has been referred to as "the Mal'ta child" because until this DNA study the biological sex of the skeleton was unknown.

"Now we can say with confidence that this individual was a male" says Graf.

Graf helped extract DNA material from the boy's upper arm and "the results surprised all of us quite a bit," she explains.

"It shows he had close genetic ties to today's Native Americans and some western Eurasians, specifically some groups living in central Asia, South Asia, and Europe. Also, he shared close genetic ties with other Ice-Age western Eurasians living in European Russia, Czech Republic and even Germany. We think these Ice-Age people were quite mobile and capable of maintaining a far-reaching gene pool that extended from central Siberia all the way west to central Europe."

Another significant result of the study is that the Mal'ta boy's people were also ancestors of Native Americans, explaining why some early Native American skeletons such as Kennewick Man were interpreted to have some European traits.

"Our study proves that Native Americans ancestors migrated to the Americas from Siberia and not directly from Europe as some have recently suggested," Graf explains.

The DNA work performed on the boy is the oldest complete genome of a human sequenced so far, the study shows. Also found near the boy's remains were flint tools, a beaded necklace and what appears to be pendant-like items, all apparently placed in the burial as grave goods.

The discovery raises new questions about the timing of human entry in Alaska and ultimately North America, a topic hotly debated in First Americans studies.

"Though our results cannot speak directly to this debate, they do indicate Native American ancestors could have been in Beringia -- extreme northeastern Russia and Alaska -- any time after 24,000 years ago and therefore could have colonized Alaska and the Americas much earlier than 14,500 years ago, the age suggested by the archaeological record."

"What we need to do is continue searching for earlier sites and additional clues to piece together this very big puzzle."

Latest Technology
Latest Technology

Download : Adobe Air 4.0.0.1090 Beta

The Adobe® AIR, runtime enables you to have your favorite web applications with you all the time. Since applications built for Adobe AIR run on your desktop computer without a web browser, they provide all the convenience of a desktop application.
Latest Technology

Bringing hobbits, dwarves and dragons to screens everywhere

You don’t need to be besties with a Wizard to share an adventure in Middle-earth—just point your favorite browser to goo.gl/TheHobbit on your laptop, phone or tablet to check out “Journey through Middle-earth,” the latest Chrome Experiment.

Inspired by the upcoming motion picture "The Hobbit: The Desolation of Smaug,” “Journey through Middle-earth” brings the locations and characters from the movie trilogy to life with a mix of modern web technologies. It was developed by North Kingdom in collaboration with Warner Bros. Pictures, New Line Cinema and Metro-Goldwyn-Mayer Pictures.

Your adventure starts on a beautiful, interactive map of Middle-earth. Zoom in to explore Trollshaw Forest, Rivendell and Dol Guldur (with more locations to come in the next few weeks). Click on each one to learn its history and meet the characters who inhabit it, or dive further to test your wits on a unique survival challenge.

The immersive 3D graphics in “Journey through Middle-earth” were built with CSS3 and WebGL, which you might recognize from previous Chrome Experiments. But “Journey through Middle-earth” is the first Chrome Experiment designed to bring this beautiful, 3D experience to mobile, thanks to support for WebGL in Chrome for Android on devices with high-end graphics cards.

The rich audio effects and sound manipulation are delivered through the Web Audio API, which is now supported on both Chrome for Android and Chrome for iPhone and iPad. Although WebGL isn’t supported on iOS, Chrome users can still experience most of “Journey through Middle-earth” on their iPhones and iPads. We can’t wait to see what sort of rich experiences developers will build as modern web technologies become available on more types of devices.

Circle +Google Chrome to stay updated as more Middle-earth locations get released in the coming weeks. You can also check out the Chromium Blog and read the team’s technical case study if you feel like geeking out a bit more.

Adventure is a click away. Just watch out for the trolls!

Posted by Posted by Christos Apartoglou, Product Marketing Manager & Part-time Dragon-slayer

Science

U.S. national survey finds frog abnormalities are rare

Nov. 20, 2013 — A 10-year study shows some good news for frogs and toads on national wildlife refuges. The rate of abnormalities such as shortened or missing legs was less than 2 percent overall -- indicating that the malformations first reported in the mid-1990s were rarer than feared. But much higher rates were found in local "hotspots," suggesting that where these problems occur they have local causes.

The results were published Nov. 18 in the journal PLOS ONE.

"We now know what the baseline is and the 2 percent level is relatively good news, but some regions need a deeper look," said Marcel Holyoak, professor of environmental science and policy at the University of California, Davis, and a co-author on the study. Hotspot regions included the Mississippi River Valley, California and south-central and eastern Alaska.

Mari Reeves, a graduate student working with Holyoak, led the data analysis and is corresponding author on the paper. Reeves now works at the U.S. Fish and Wildlife Service in Alaska.

Fieldwork for the study was carried out by the Fish and Wildlife Service at 152 refuges across the country between 2000 and 2009. Researchers collected more than 68,000 frogs and toads for the study. The complete dataset is available to researchers and the public online.

The aim of the study was to understand where and when these abnormalities occur -- are they widespread, or localized? Are they persistent, or do they appear and fade away? -- rather than to identify specific causes, Holyoak said. Understanding the patterns of these hotspots in space and time can help researchers home in on likely causes, he said.

The results show that abnormality hotspots occur in specific places, but within these hotspots the rate of malformations can change over time, Holyoak said.

"We see them at an elevated frequency one year or for a few years, and then they recover," he said.

The most common problems observed were missing or shortened toes or legs, and skin cysts. Only 12 cases of frogs with extra legs were found.

Many different potential causes have been put forward for the abnormalities, including pollution from industry or agriculture, parasites, ultraviolet exposure and naturally occurring heavy metals leaching into water bodies. The exact cause may vary from place to place, Holyoak noted.

The study comes against a background of a general decline in amphibian populations both in the U.S. and worldwide. For example, the California red-legged frog celebrated by Mark Twain's story is now listed as threatened. Frogs and toads may be especially sensitive to changes in climate and air or water quality. It's not clear whether hotspots of malformations contribute to this general decline, Holyoak said, but the new dataset will help researchers explore the problem.

The study was funded by the Fish and Wildlife Service. Other authors were: Kimberly Medley and Pieter Johnson, University of Colorado, Boulder; Alfred Pinkney, U.S. Fish and Wildlife Service, Annapolis; and Michael Lannoo, Indiana University School of Medicine.

Science

Listen to this: New research upends understanding of how humans perceive sound

Nov. 20, 2013 — A key piece of the scientific model used for the past 30 years to help explain how humans perceive sound is wrong, according to a new study by researchers at the Stanford University School of Medicine.

The long-held theory helped to explain a part of the hearing process called "adaptation," or how humans can hear everything from the drop of a pin to a jet engine blast with high acuity, without pain or damage to the ear. Its overturning could have significant impact on future research for treating hearing loss, said Anthony Ricci, PhD, the Edward C. and Amy H. Sewall Professor of Otolaryngology and senior author of the study.

"I would argue that adaptation is probably the most important step in the hearing process, and this study shows we have no idea how it works," Ricci said. "Hearing damage caused by noise and by aging can target this particular molecular process. We need to know how it works if we are going to be able to fix it."

The study was published Nov. 20 in Neuron. The lead author is postdoctoral scholar Anthony Peng, PhD.

Deep inside the ear, specialized cells called hair cells detect vibrations caused by air pressure differences and convert them into electrochemical signals that the brain interprets as sound. Adaptation is the part of this process that enables these sensory hair cells to regulate the decibel range over which they operate. The process helps protect the ear against sounds that are too loud by adjusting the ears' sensitivity to match the noise level of the environment.

The traditional explanation for how adaptation works, based on earlier research on frogs and turtles, is that it is controlled by at least two complex cellular mechanisms both requiring calcium entry through a specific, mechanically sensitive ion channel in auditory hair cells. The new study, however, finds that calcium is not required for adaptation in mammalian auditory hair cells and posits that one of the two previously described mechanisms is absent in auditory cochlear hair cells.

Experimenting mostly on rats, the Stanford scientists used ultrafast mechanical stimulation to elicit responses from hair cells as well as high-speed, high-resolution imaging to track calcium signals quickly before they had time to diffuse. After manipulating intracellular calcium in various ways, the scientists were surprised to find that calcium was not necessary for adaptation to occur, thus challenging the 30-year-old hypothesis and opening the door to new models of mechanotransduction (the conversion of mechanical signals into electrical signals) and adaptation.

"This somewhat heretical finding suggests that at least some of the underlying molecular mechanisms for adaptation must be different in mammalian cochlear hair cells as compared to that of frog or turtle hair cells, where adaptation was first described," Ricci said.

The study was conducted to better understand how the adaptation process works by studying the machinery of the inner ear that converts sound waves into electrical signals.

"To me this is really a landmark study," said Ulrich Mueller, PhD, professor and chair of molecular and cellular neuroscience at the Scripps Research Institute in La Jolla, who was not involved with the study. "It really shifts our understanding. The hearing field has such precise models -- models that everyone uses. When one of the models tumbles, it's monumental."

Humans are born with 30,000 cochlear and vestibular hair cells per ear. When a significant number of these cells are lost or damaged, hearing or balance disorders occur. Hair cell loss occurs for multiple reasons, including aging and damage to the ear from loud sounds. Damage or impairment to the process of adaptation may lead to the further loss of hair cells and, therefore, hearing. Unlike many other species, including birds, humans and other mammals are unable to spontaneously regenerate these hearing cells.

As the U.S. population has aged and noise pollution has grown more severe, health experts now estimate that one in three adults over the age of 65 has developed at least some degree of hearing disability because of the destruction of these limited number of hair cells.

"It's by understanding just how the inner machinery of the ear works that scientists hope to eventually find ways to fix the parts that break," Ricci said. "So when a key piece of the puzzle is shown to be wrong, it's of extreme importance to scientists working to cure hearing loss."

Stanford postdoctoral scholar Thomas Effertz, PhD, is also an author of the study.

Science

Scientists break a theoretical time barrier on bouncing droplets

Nov. 20, 2013 — Those who study hydrophobic materials -- water-shedding surfaces such as those found in nature and created in the laboratory -- are familiar with a theoretical limit on the time it takes for a water droplet to bounce away from such a surface. But MIT researchers have now found a way to burst through that perceived barrier, reducing the contact time by at least 40 percent.

Their finding is reported in a paper in the journal Nature co-authored by Kripa Varanasi, the Doherty Associate Professor of Mechanical Engineering at MIT, along with James Bird, a former MIT postdoc who is now an assistant professor of mechanical engineering at Boston University, former MIT postdoc Rajeev Dhiman, and recent MIT PhD recipient Hyukmin Kwon.

"The time that the drop stays in contact with a surface is important because it controls the exchange of mass, momentum, and energy between the drop and the surface," Varanasi says. "If you can get the drops to bounce faster, that can have many advantages."

For example, in trying to prevent the buildup of ice on an airplane wing, the contact time of raindrops is critical: The longer a droplet stays in contact with a surface before bouncing off, the greater its chances of freezing in place.

According to the theoretical limit, the minimum time a bouncing droplet can stay in contact with a surface -- first spreading out into a pancake-like shape, then pulling back inward due to surface tension and bouncing away -- depends on the time period of oscillations in a vibrating drop, also known as the Rayleigh time. The way to achieve that minimum contact time, the conventional wisdom holds, is to minimize interaction between the water and the surface, such as by creating low-adhesion superhydrophobic surfaces.

But Varanasi's team found that increasing the surface interaction in a particular way can speed the process beyond that previous limit. To facilitate this interaction, they added macroscopic features -- such as ridges that break a droplet's symmetry and can serve to split it, causing it to recoil in highly irregular shapes. These ridged surfaces can have contact times that are 40 percent shorter than control surfaces.

"We've demonstrated that we can use surface texture to reshape a drop as it recoils, in such a way that the overall contact time is significantly reduced," says Bird, the paper's lead author. "The upshot is that the surface stays drier longer if this contact time is reduced, which has the potential to be useful for a variety of applications."

With this reduction in contact time, the researchers were able to show that droplets bounced off before freezing on these symmetry-breaking surfaces; on control surfaces, droplets arrested and solidified on the surface. "We can reduce it further," Varanasi says, through optimization of the texture. "I hope we can manage to get a 70 to 80 percent reduction."

Varanasi's team's findings may also have implications for ecology: The researchers found that some butterfly wings naturally produce the same effect, limiting the likelihood that water will spread out over the wings and curtail their aerodynamic properties -- a clear survival advantage. (In the case of the wings, it is the veins within that create the droplet-busting surface ridges.)

Similarly, the veins of nasturtium leaves, unlike those of most leaves, are on top, where they serve to break up droplets that land there. The MIT researchers found that drops bounced off both butterfly wings and nasturtium leaves faster than they bounced off lotus leaves, which are often considered the "gold standard" of nonwetting surfaces.

Varanasi points out that creating the needed surface textures is actually very simple: The ridges can be produced by ordinary milling tools, such as on the surface of an aluminum plate, making the process scalable to industrial levels. Such textures could also be created on fabric surfaces, he says, as a potential replacement for existing waterproof coatings whose safety has been called into question by the Environmental Protection Agency.

Howard Stone, a professor of mechanical and aerospace engineering at Princeton University who was not involved in this work, says, "This paper provides new ideas and new insights for how a surface texture can reduce the contact time of a bouncing drop. … It will be interesting to see possible ways these ideas might be applied in the future."

In addition to waterproofing and prevention of surface icing, the technique could have applications in other areas, Varanasi says. For example, the turbine blades in electric power plants become less efficient if water builds up on their surfaces. "If you can make the blades stay dry longer, you get a bump up in efficiency," he says. The new technique could also reduce corrosion on surfaces where droplets, especially if they are acidic or contain contaminants, contribute to degradation.

Video: http://www.youtube.com/watch?v=-qQirthIyh0

The research received support from the Defense Advanced Research Projects Agency, the MIT Energy Initiative, the National Science Foundation, and the MIT-Deshpande Center for Technological Innovation.

Science

3-D printing hits fast lane: Engineers cut time to 3-D-print heterogeneous objects from hours to minutes

Nov. 20, 2013 — Researchers at the USC Viterbi School of Engineering have developed a faster 3D printing process and are now using it to model and fabricate heterogeneous objects, which comprise multiple materials.

Although 3D printing -- or direct digital manufacturing -- has the potential to revolutionize various industries by providing faster, cheaper and more accurate manufacturing options, fabrication time and the complexity of multi-material objects have long been a hurdle to its widespread use in the marketplace. With this newly developed 3D printing process, however, USC Viterbi professor Yong Chen and his team have shaved the fabrication time down to minutes, bringing the manufacturing world one step closer to achieving its goal.

"Digital material design and fabrication enables controlled material distributions of multiple base materials in a product component for significantly improved design performance. Such fabrication capability opens up exciting new options that were previously impossible," said Yong Chen, Ph.D., professor in the Daniel J. Epstein Department of Industrial and Systems Engineering and the study's lead researcher.

Traditional modeling and prototyping approaches used to take days, but over the past several decades various additive manufacturing (AM) processes have been developed to fabricate both homogeneous and heterogeneous objects more quickly. Currently, AM processes such as multi-jet modeling, which create a solid 3D object from a digital model by laying down successive layers of material, can fabricate a complex object in a matter of hours.

Last year, Chen and another team of USC Viterbi researchers improved an AM-related process called mask-image-projection-based stereolithography (MIP-SL) to drastically speed up the fabrication of homogeneous 3D objects. In the MIP-SL process, a 3D digital model of an object is sliced by a set of horizontal planes and each slice is converted into a two-dimensional mask image. The mask image is then projected onto a photocurable liquid resin surface and light is projected onto the resin to cure it in the shape of the related layer.

Furthermore, the USC Viterbi team developed a two-way movement design for bottom-up projection so that the resin could be quickly spread into uniform thin layers. As a result, production time was cut from hours to a few minutes. In their latest paper, the team successfully applies this more efficient process to the fabrication of heterogeneous objects that comprise different materials that cure at different rates. This new 3D printing process will allow heterogeneous prototypes and objects such as dental and robotics models to be fabricated more cost- and time-efficiently than ever before.

In future work, Chen and his team will investigate how to develop an automatic design approach for heterogeneous material distribution according to user-specified physical properties and how to improve the fabrication speed.

Chen and USC Viterbi industrial and systems engineering doctoral candidates students Pu Huang and Dongping Deng are presenting their findings at ASME's 2013 International Mechanical Engineering Congress and Exposition in San Diego on November 20th.

Video: http://vimeo.com/79412743

Google, Latest Technology

Avoiding delays at the U.S.-Canada border, thanks to NITTEC and Google Maps

Posted by Athena Hutchins, Executive Director, NITTEC

Editor's note: Today’s guest blogger is Athena Hutchins, executive director of the Niagara International Transportation Technology Coalition (NITTEC), a group of agencies improving traffic mobility and safety in Western New York and Southern Ontario. Join Athena on a webinar to hear the NITTEC story from her directly on December, 12 at 11-12 PST. Register here.

There’s a lot of traffic activity at the border of Western New York State and Southern Ontario: every month, an average of one million vehicles cross the three bridges with border checkpoints between the U.S. and Canada. Our job at Niagara International Transportation Technology Coalition (NITTEC) is to help vacationers and commuters in the Niagara Falls area see any traffic and road issues that might stand in their way. That’s why we created our new map — built with Google Maps — which takes a complex mix of data from local, state and federal agencies and gives drivers a single view of their trip.

We’ve used Google Maps on the NITTEC website since 2007. This year we developed a multilayered map as part of our efforts to improve traffic movement in the cross-border region. The new map uses the Google Maps API to help us pull together a wealth of useful data, including construction projects, delays and border crossing times. This information is available piecemeal from other agencies, but a traveler would have a hard time patching together a true picture of traffic conditions at the border, especially since we’re dealing with data from two countries.

The map is on the homepage of our new NITTEC website, so visitors can quickly find out how long it will take to get to the border, how much time they’ll have to wait at checkpoints and which alternate routes might be less congested. For instance, when the Lewiston-Queenston Bridge has long wait times, a quick glance at the map can tell drivers if they’re better off heading for the Peace Bridge or the Rainbow Bridge. Travelers can use the map’s control panel to choose which overlays they see, such as satellite views, highways, and live camera images.

To develop the new map, we incorporated 10 data feeds from across our 30 coalition agencies. The map refreshes every 20 seconds, using this constantly updated information. A mobile version of the map allows drivers approaching the border to get up-to-date info while they’re en route.

People are already familiar with Google Maps, so seeing our map provides clear, customizable and up-to-date traffic information that can be viewed at a glance and that’s easy to digest. It also helps us send a message about the NITTEC brand – that we’re on a mission to help people in the area get where they’re going safely and more efficiently.