Tuesday, September 29, 2009

SANDIA HOPPING ROBOTS TO BOLSTER TROOP CAPABILITIES

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Boston Dynamics, developer of advanced dynamic robots such as BigDog and PETMAN, has been awarded a contract by Sandia to develop the next generation of the Precision Urban Hopper, meaning Sandia‘s hopping robots may soon be in combat.

When fully operational, the four-wheeled hopper robots will navigate autonomously by wheel and jump – with one mighty leg – onto or over obstacles of more than 25 feet, said Jon Salton, Sandia program manager.

“The Precision Urban Hopper is part of a broad effort to bolster the capabilities of troops and special forces engaged in urban combat, giving them new ways to operate unfettered in the urban canyon,” Salton said.

The development program, funded by Defense Advanced Research Projects Agency, Department of Defense’s advanced technology organization, has a 12-month design phase followed by a six-month build phase, with testing and delivery planned for late 2010.

As part of the ongoing DARPA project, Sandia developed the shoebox-sized, GPS-guided, unmanned ground robots.

The demonstrated hopping capability of the robots allows the small unmanned ground vehicles to overcome as many as 30 obstacles that are 40-60 times their own size. Hopping mobility has been shown to be five times more efficient than hovering when traversing obstacles at heights under 10 meters, which allows longer station-keeping time for the same amount of fuel.

The wheeled robotic platform adapts to the urban environment in real time and provides precision payload deployment to any point of the urban jungle while remaining lightweight and small. Researchers addressed several technical challenges, including appropriate management of shock forces during landing, controlling hop height from varying terrain including concrete, asphalt, sand and vegetation and controlling landings to limit tumbling.

An overall goal of the robots is to decrease the number of casualties in combat. To that end, the hopping robots will provide enhanced situational awareness for shaping the outcome of the immediate local combat situation, Salton said. Their compact, lightweight design makes them portable, and their semiautonomous capability greatly reduces the workload burden of the operator.

In addition to providing military assistance, the hopping capabilities of the robots could be used in law enforcement, homeland security, search and rescue applications in challenging terrain and in planetary exploration, Salton said.

”We are delighted to win this project and get a chance to work with Sandia on such a novel and potentially useful robot,” said Marc Raibert, president and founder of Boston Dynamics. “The program gives us a chance to apply our special brand of advanced controls and stabilization to a system that can help our warfighters in the near future.”

(Photo: Randy Montoya)

Sandia National Laboratories

STUDY OF ISOLATED SNAKES COULD HELP SHED LIGHT ON VENOM COMPOSITION

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While studying a way to more safely and effectively collect snake venom, University of Florida researchers have noticed the venom delivered by an isolated population of Florida cottonmouth snakes may be changing in response to their diet.

Scientists used a portable nerve stimulator to extract venom from anesthetized cottonmouths, producing more consistent extraction results and greater amounts of venom, according to findings published in August in the journal Toxicon.

The study of venoms is important for many reasons, scientists say.

“The human and animal health benefits include understanding the components of venom that cause injury and developing better antivenin,” said Darryl Heard, an associate professor in the UF College of Veterinary Medicine’s department of small animal clinical sciences. “In addition, the venom components have the potential to be used for diagnostic tests and the development of new medical compounds.”

But in addition to showing the extraction method is safer, more effective and less stressful to both snake and handler than the traditional “milking” technique, Heard and Ryan McCleary, a Ph.D. candidate in biology in UF’s College of Liberal Arts and Sciences, discovered the venom from these particular snakes differs from that of mainland snakes, likely because of their unique diet of dead fish dropped by seabirds.

Heard and McCleary collaborated to develop a safe, reliable and humane technique for collecting venom from cottonmouths as part of a larger study on a specific population of snakes that reside on Seahorse Key, an isolated island near Cedar Key on the Florida’s Gulf Coast.

The venom collection study included data from 49 snakes on Seahorse Key.

“Snakes on this island are noted for their large size,” said Heard, a zoological medicine veterinarian with additional expertise in anesthesia. He added that Harvey Lillywhite, a professor of biology at UF and McCleary’s predoctoral adviser, has confirmed that cottonmouths on Seahorse Key eat primarily dead fish dropped by birds in a large seabird rookery.

Lillywhite also directs UF’s Seahorse Key Marine Laboratory, located in the Cedar Keys National Wildlife Refuge. McCleary hopes to build on earlier studies about the snakes’ ecology and to explore whether evolutionary changes may have affected the composition of the snakes’ venom.

“My interest is in the evolutionary aspect,” McCleary said. “If these snakes already have an abundant source of dead prey, why do they need venom?”

Preliminary findings show some differences in venom components, he added.

Traditionally, venom has been collected from venomous snakes by manually restraining the animal behind the head and having it bite a rubber membrane connected to a collecting chamber.

“This requires the capture of an awake snake, which increases the risk of human envenomation and is also stressful to the snake,” Heard said, adding that manual collection of venom also does not guarantee that all of the venom is collected.

(Photo: Sarah Kiewel/University of Florida)

CLIMATE CHANGE MEANS NORTHERN HIGH LATITUDES WILL RECEIVE LESS ULTRAVIOLET RADIATION

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Physicists at the University of Toronto have discovered that changes in the Earth's ozone layer due to climate change will reduce the amount of ultraviolet (UV) radiation in northern high latitude regions such as Siberia, Scandinavia and northern Canada. Other regions of the Earth, such as the tropics and Antarctica, will instead face increasing levels of UV radiation.

"Climate change is an established fact, but scientists are only just beginning to understand its regional manifestations," says Michaela Hegglin, a postdoctoral fellow in the Department of Physics and the lead author of the study published this month in Nature Geoscience.

Using a sophisticated computer model, Hegglin and U of T physicist Theodore Shepherd determined that 21st-century climate change will alter atmospheric circulation, increasing the flux of ozone from the upper to the lower atmosphere and shifting the distribution of ozone within the upper atmosphere. The result will be a change in the amount of UV radiation reaching the Earth's surface which varies dramatically between regions: e.g., up to a 20 per cent increase in UV radiation over southern high latitudes during spring and summer and a nine per cent decrease in UV radiation over northern high latitudes by the end of the century.

While the effects of increased UV have been widely studied because of the problem of ozone depletion, decreased UV could have adverse effects too, e.g., on vitamin D production for people in regions with limited sunlight such as the northern high latitudes.

"Both human and ecosystem health are affected by air quality and by UV radiation," said Shepherd. "While there has been much research on the impact of climate change on air quality, our work shows that this research needs to include the effect of changes in stratospheric ozone. And while there has been much research on the impact of ozone depletion on UV radiation and its impacts on human and ecosystem health, the notion that climate change could also affect UV radiation has not previously been considered. This adds to the list of potential impacts of climate change, and is especially important for Canada as northern high latitudes are particularly affected."

University of Toronto

ROME WAS BUILT IN A DAY, WITH HUNDREDS OF THOUSANDS OF DIGITAL PHOTOS

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The ancient city of Rome was not built in a day. It took nearly a decade to build the Colosseum, and almost a century to construct St. Peter's Basilica. But now the city, including these landmarks, can be digitized in just a matter of hours.

A new computer algorithm developed at the University of Washington uses hundreds of thousands of tourist photos to automatically reconstruct an entire city in about a day.

The tool is the most recent in a series developed at the UW to harness the increasingly large digital photo collections available on photo-sharing Web sites. The digital Rome was built from 150,000 tourist photos tagged with the word "Rome" or "Roma" that were downloaded from the popular photo-sharing Web site, Flickr.

Computers analyzed each image and in 21 hours combined them to create a 3-D digital model. With this model a viewer can fly around Rome's landmarks, from the Trevi Fountain to the Pantheon to the inside of the Sistine Chapel.

"How to match these massive collections of images to each other was a challenge," said Sameer Agarwal, a UW acting assistant professor of computer science and engineering and lead author of a paper being presented in October at the International Conference on Computer Vision in Kyoto, Japan. Until now, he said, "even if we had all the hardware we could get our hands on and then some, a reconstruction using this many photos would take forever."

Earlier versions of the UW photo-stitching technology are known as Photo Tourism. That technology was licensed in 2006 to Microsoft, which now offers it as a free tool called Photosynth.

"With Photosynth and Photo Tourism, we basically reconstruct individual landmarks. Here we're trying to reconstruct entire cities," said co-author Noah Snavely, who developed Photo Tourism as his UW doctoral work and is now an assistant professor at Cornell University.

Other co-authors of the new paper are Rick Szeliski of Microsoft Research, UW computer science professor Steve Seitz and UW graduate student Ian Simon.

In addition to Rome, the team recreated the Croatian coastal city of Dubrovnik, processing 60,000 images in less than 23 hours using a cluster of 350 computers, and Venice, Italy, processing 250,000 images in 65 hours using a cluster of 500 computers. Many historians see Venice as a candidate for digital preservation before water does more damage to the city, the researchers said.

Transitioning from landmarks to cities -- going from hundreds of photos to hundreds of thousands of photos -- is not trivial. Previous versions of the Photo Tourism software matched each photo to every other photo in the set. But as the number of photos increases the number of matches explodes, increasing with the square of the number of photos. A set of 250,000 images would take at least a year for 500 computers to process, Agarwal said. A million photos would take more than a decade.

The newly developed code works more than a hundred times faster than the previous version. It first establishes likely matches and then concentrates on those parts. The code also uses parallel processing techniques, allowing it to run simultaneously on many computers, or even on remote servers connected through the Internet.

The new, faster code makes it possible to tackle more ambitious projects.

"If a city reconstruction took several months, it would be just about building Rome," Seitz said. "But on a timeline of one day you can methodically start going through all the cities and start building models of them."

This technique could create online maps that offer viewers a virtual-reality experience. The software could build cities for video games automatically, instead of doing so by hand. It also might be used in architecture for digital preservation of cities, or integrated with online maps, Seitz said.

In the near term, the "Rome in a Day" code could be used with Photo Tourism, Photosynth or other software designed to view the model output.

(Photo: University of Washington)

University of Washington

TRANSITION FROM EGG-LAYING TO LIVE-BORN

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A new analysis of extinct sea creatures suggests that the transition from egg-laying to live-born young opened up evolutionary pathways that allowed these ancient species to adapt to and thrive in open oceans.

The evolutionary sleuthing is described in the journal Nature by scientists at Harvard University and the University of Reading who also report that the evolution of live-born young depended crucially on the advent of genes — rather than incubation temperature — as the primary determinant of offspring sex.

Having drawn this link in three lineages of extinct marine reptiles — mosasaurs, sauropterygians, and ichthyosaurs — the scientists say that genetic, or chromosomal, sex determination may have played a surprisingly strong role in adaptive radiations and the colonization of the world’s oceans by a diverse array of species.

“Determining sex with genetic mechanisms allowed marine reptiles to give live birth, in the water, as opposed to laying eggs on a nesting beach,” says Chris Organ, a research fellow in Harvard’s Department of Organismic and Evolutionary Biology. “This freed these species from the need to move and nest on land. As a consequence, extreme physical adaptations evolved in each group, such as the fluked tails, dorsal fins, and the winglike limbs of ichthyosaurs.”

Mosasaurs, sauropterygians, and ichthyosaurs invaded the Mesozoic seas between 251 million and 100 million years ago. All three groups of extinct marine reptiles breathed air, but evolved other adaptations to life in the open ocean, such as fin-shaped limbs, streamlined bodies, and changes in bone structure. Some evolved into enormous predators, such as porpoiselike ichthyosaurs that grew to more than 20 meters in length. Ichthyosaurs, and possibly mosasaurs, even evolved tail-first birth, an adaptation that helps modern whales and porpoises avoid drowning during birth.

“Losing the requirement of dry land during the life cycle of ichthyosaurs and other marine reptiles freed them to lead a completely aquatic existence, a shift that seems advantageous in light of the diversification that followed,” says Daniel E. Janes, a research associate in Harvard’s Department of Organismic and Evolutionary Biology.

Even though populations of most animals have males and females, the way sex is determined in offspring varies. Some animals rely primarily on sex chromosomes, as in humans where two X chromosomes make a female and an X and a Y chromosome make a male. Among living marine species, whales, porpoises, manatees, and sea snakes have chromosomal sex determination.

In sea turtles and saltwater crocodiles, on the other hand, the sex of offspring is generally determined by the temperature at which eggs incubate. These species are also bound to a semiterrestrial existence because their gas-exchanging hard-shelled eggs must be deposited on land.

“No one has clearly understood how sex determination has co-evolved with live birth and egg laying,” Organ says.

Organ, Janes, and colleagues show that evolution of live birth in a species depends on the prior evolution of genetic sex determination. Because the fossilized remains of pregnant mosasaurs, sauropterygians, and ichthyosaurs show that these species gave birth to live young, they must also have employed genetic sex determination, a point on which the fossil record is silent.

(Photo: Mark Sloan/HMNH)

Harvard University

DAILY BATHROOM SHOWERS MAY DELIVER FACE FULL OF PATHOGENS

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While daily bathroom showers provide invigorating relief and a good cleansing for millions of Americans, they also can deliver a face full of potentially pathogenic bacteria, according to a surprising new University of Colorado at Boulder study.

The researchers used high-tech instruments and lab methods to analyze roughly 50 showerheads from nine cities in seven states that included New York City, Chicago and Denver. They concluded about 30 percent of the devices harbored significant levels of Mycobacterium avium, a pathogen linked to pulmonary disease that most often infects people with compromised immune systems but which can occasionally infect healthy people, said CU-Boulder Distinguished Professor Norman Pace, lead study author.

It's not surprising to find pathogens in municipal waters, said Pace. But the CU-Boulder researchers found that some M. avium and related pathogens were clumped together in slimy "biofilms" that clung to the inside of showerheads at more than 100 times the "background" levels of municipal water. "If you are getting a face full of water when you first turn your shower on, that means you are probably getting a particularly high load of Mycobacterium avium, which may not be too healthy," he said.

The study appeared in the Sept. 14 online edition of the Proceedings of the National Academy of Sciences. Co-authors of the study included CU-Boulder researchers Leah Feazel, Laura Baumgartner, Kristen Peterson and Daniel Frank and University Colorado Denver pediatrics department Associate Professor Kirk Harris. The study is part of a larger effort by Pace and his colleagues to assess the microbiology of indoor environments and was supported by the Alfred P. Sloan Foundation.

Research at National Jewish Hospital in Denver indicates that increases in pulmonary infections in the United States in recent decades from so-called "non-tuberculosis" mycobacteria species like M. avium may be linked to people taking more showers and fewer baths, said Pace. Water spurting from showerheads can distribute pathogen-filled droplets that suspend themselves in the air and can easily be inhaled into the deepest parts of the lungs, he said.

Symptoms of pulmonary disease caused by M. avium can include tiredness, a persistent, dry cough, shortness of breath, weakness and "generally feeling bad," said Pace. Immune-compromised people like pregnant women, the elderly and those who are fighting off other diseases are more prone to experience such symptoms, said Pace, a professor in the molecular, cellular and developmental biology department.

The CU-Boulder researchers sampled showerheads in homes, apartment buildings and public places in New York, Illinois, Colorado, Tennessee and North Dakota.

Although scientists have tried cell culturing to test for showerhead pathogens, the technique is unable to detect 99.9 percent of bacteria species present in any given environment, said Pace. A molecular genetics technique developed by Pace in the 1990s allowed researchers to swab samples directly from the showerheads, isolate DNA, amplify it using the polymerase chain reaction, or PCR, and determine the sequences of genes present in order to pinpoint particular pathogen types.

"There have been some precedents for concern regarding pathogens and showerheads," said Pace. "But until this study we did not know just how much concern."

During the early stages of the study, the CU team tested showerheads from smaller towns and cities, many of which were using well water rather than municipal water. "We were starting to conclude that pathogen levels we detected in the showerheads were pretty boring," said Feazel, first author on the study. "Then we worked up the New York data and saw a lot of M. avium. It completely reinvigorated the study."

In addition to the showerhead swabbing technique, Feazel took several individual showerheads, broke them into tiny pieces, coated them with gold, used a fluorescent dye to stain the surfaces and used a scanning electron microscope to look at the surfaces in detail. "Once we started analyzing the big metropolitan data, it suddenly became a huge story to us," said Feazel, who began working in Pace's lab as an undergraduate.

In Denver, one showerhead in the study with high loads of the pathogen Mycobacterium gordonae was cleaned with a bleach solution in an attempt to eradicate it, said Pace. Tests on the showerhead several months later showed the bleach treatment ironically caused a three-fold increase in M. gordonae, indicating a general resistance of mycobacteria species to chlorine.

Previous studies by Pace and his group found massive enrichments of M. avium in "soap scum" commonly found on vinyl shower curtains and floating above the water surface of warm therapy pools. A 2006 therapy pool study led by Pace and CU-Boulder Professor Mark Hernandez showed high levels of M. avium in the indoor pool environment were linked to a pneumonia-like pulmonary condition in pool attendants known as "lifeguard lung," leading the CU team into the showerhead study, said Pace.

Additional studies under way by Pace's team include analyses of air in New York subways, hospital waiting rooms, office buildings and homeless shelters. Indoor air typically has about 1 million bacteria per cubic meter and municipal tap water has rough 10 million bacteria per cubic meter, said Pace.

So is it dangerous to take showers? "Probably not, if your immune system is not compromised in some way," said Pace. "But it's like anything else -- there is a risk associated with it." Pace said since plastic showerheads appear to "load up" with more pathogen-enriched biofilms, metal showerheads may be a good alternative.

"There are lessons to be learned here in terms of how we handle and monitor water," said Pace. "Water monitoring in this country is frankly archaic. The tools now exist to monitor it far more accurately and far less expensively that what is routinely being done today."

In 2001 the National Academy of Sciences awarded Pace the Selman Waxman Award -- considered the nation's highest award in microbiology -- for pioneering the molecular genetic techniques he now uses to rapidly detect, identify and classify microbe species using nucleic acid technology without the need for lab cultivation. That same year he was awarded a MacArthur Foundation "genius grant" for his work.

University of Colorado

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