Thursday, January 13, 2011

New Predator 'Dawn Runner' Discovered in Early Dinosaur Graveyard.

A team of paleontologists and geologists from Argentina and the United States on Jan. 13 announced the discovery of a lanky dinosaur that roamed South America in search of prey as the age of dinosaurs began, approximately 230 million years ago.

Sporting a long neck and tail and weighing only 10 to 15 pounds, the new dinosaur has been named Eodromaeus, the "dawn runner."
"It really is the earliest look we have at the long line of meat eaters that would ultimately culminate in Tyrannosaurus rex near the end of the dinosaur era," said Paul Sereno, University of Chicago paleontologist and National Geographic Explorer-in-Residence. "Who could foretell what evolution had in store for the descendants of this pint-sized, fleet-footed predator?"

Sereno and his colleagues describe a near-complete skeleton of the new species, based on the rare discovery of two individuals found side-by-side, in the Jan. 14, 2011 issue of the journal Science. The paper presents a new snapshot of the dawn of the dinosaur era -- a key period that has garnered less attention than the dinosaurs' demise. "It's more complex than some had supposed," Sereno said.

Set in picturesque foothills of the Andes, the site of discovery is known as the "Valley of the Moon," said the report's lead author, Ricardo Martinez of Argentina's National University of San Juan. For dinosaur paleontologists, it is like no other.

"Two generations of field work have generated the single best view we have of the birth of the dinosaurs," Martinez said. "With a hike across the valley, you literally walk over the graveyard of the earliest dinosaurs to a time when they ultimately dominate."

The area was once a rift valley in the southwest corner of the supercontinent Pangaea. Sediments covered skeletons over a period of five million years, eventually accumulating a thickness of more than 2,000 feet (700 meters).
Volcanoes associated with the nascent Andes Mountains occasionally spewed volcanic ash into the valley, allowing the team to use radioactive elements in the ash layers to determine the age of the sediments.

"Radioisotopes -- our clocks in the rocks -- not only placed the new species in time, about 230 million years ago, but also gave us perspective on the development of this key valley," said Paul Renne, director of the Berkeley Geochronology Center in California. "About five million years of time are represented in these layers, from one end to the other."

In the oldest rocks Eodromaeus lived alongside Eoraptor, a similar-sized, plant-eating dinosaur that Sereno and colleagues discovered in the valley in 1991. Eoraptor's descendants would eventually include the giant, long-necked sauropods. Eodromaeus, with stabbing canine teeth and sharp-clawed grasping hands, is the pint-sized precursor to later meat-eaters called theropods, and eventually to birds.

"We're looking at a snapshot of early dinosaur life. Their storied evolutionary careers are just unfolding, but at this point they're actually quite similar," Sereno said.

Eodromaeus at the root of the dinosaur family tree
Vexing scientific questions at the dawn of the dinosaur era include what gave them an edge over competitors, and how quickly did they rise to dominance? In Eodromaeus' day, other kinds of reptiles outnumbered dinosaurs, such as squat lizard-like rhynchosaurs and mammal-like reptiles. The authors logged thousands of fossils unearthed in the valley to find, as Martinez remarked, that "dinosaurs took their sweet time to dominate the scene."

Their competitors dropped out sequentially over several million years, not at a single horizon in the valley.

In the red cliffs on the far side of the valley, larger plant- and meat-eating dinosaurs had evolved many times the size of Eoraptor and Eodromaeus, but it would be even later when they dominated all land habitats in the succeeding Jurassic and Cretaceous periods.

"The story from this valley suggests that there was no single advantage or lucky break for dinosaurs but rather a long period of evolutionary experimentation in the shadow of other groups," Sereno said. Other researchers on the paper tracked climate change and other conditions across the layers of the valley. "The dawn of the age of dinosaurs," Martinez remarked, "is coming into focus."


Pint-sized Eodromaeus (“dawn runner”) weighed only 10 to 15 pounds and measured about 4 feet in length from snout to tail tip. It lies very close to the ancestor of all meat-eating dinosaurs, including Tyrannosaurus. (Credit: Illustration by Todd Marshall)

Tuesday, January 11, 2011

Mountain Glacier Melt to Contribute 12 Centimeters to World Sea-Level Increases by 2100.

The largest contributors to projected global sea-level increases are glaciers in Arctic Canada, Alaska and landmass bound glaciers in the Antarctic. Glaciers in the European Alps, New Zealand, the Caucasus, Western Canada and the Western United Sates--though small absolute contributors to global sea-level increases--are projected to lose more than 50 per cent of their current ice volume.

The study modelled volume loss and melt off from 120,000 mountain glaciers and ice caps, and is one of the first to provide detailed projections by region. Currently, melt from smaller mountain glaciers and ice caps is responsible for a disproportionally large portion of sea level increases, even though they contain less than one per cent of all water on Earth bound in glacier ice.

"There is a lot of focus on the large ice sheets but very few global scale studies quantifying how much melt to expect from these smaller glaciers that make up about 40 percent of the entire sea-level rise that we observe right now," says Valentina Radic, a postdoctoral researcher with the Department of Earth and Ocean Sciences and lead author of the study.

Increases in sea levels caused by the melting of the Greenland and Antarctic ice sheets, and the thermal expansion of water, are excluded from the results.
Radic and colleague Regine Hock at the University of Alaska, Fairbanks, modelled future glacier melt based on temperature and precipitation projections from 10 global climate models used by the Intergovernmental Panel on Climate Change.

"While the overall sea level increase projections in our study are on par with IPCC studies, our results are more detailed and regionally resolved," says Radic. "This allows us to get a better picture of projected regional ice volume change and potential impacts on local water supplies, and changes in glacier size distribution."

Global projections of sea level rises from mountain glacier and ice cap melt from the IPCC range between seven and 17 centimetres by the end of 2100. Radic's projections are only slightly higher, in the range of seven to 18 centimetres.

Radic's projections don't include glacier calving--the production of icebergs. Calving of tide-water glaciers may account for 30 per cent to 40 per cent of their total mass loss.

"Incorporating calving into the models of glacier mass changes on regional and global scale is still a challenge and a major task for future work," says Radic.
However, the new projections include detailed projection of melt off from small glaciers surrounding the Greenland and Antarctic ice sheets, which have so far been excluded from, or only estimated in, global assessments.


Aerial photo of Mount Garibaldi, Diamond Head with Howe Sound and Squamish British Columbia below. Melt off from small mountain glaciers and ice caps will contribute about 12 centimetres to world sea-level increases by 2100, according to University of British Columbia research. (Credit: iStockphoto/Douglas Burne)

Sunday, January 9, 2011

Dracula Orchids and Goblin Spiders.

Dracula orchids tempt flies by masquerading as mushrooms. Goblin spiders lurk unseen in the world's leaf litter. The natural world is often just as haunting as the macabre costumes worn on city streets, as highlighted by two studies published this year by curators in the Division of Invertebrate Zoology at the American Museum of Natural History, David Grimaldi and Norman Platnick.

Dracula Orchids
According to Grimaldi and colleagues, fruit flies (Drosophilidae) of the genus Zygothrica typically swarm on mushrooms and other rain forest fungi. But one group of orchids in the American tropics takes advantage of their preferences, duping the hapless flies into pollinating them with the scent and appearance of mushrooms. These orchids are from the genus Dracula, named so to keep the spirit of a former name, Masdevallia, when it was realized that there were separate orchid groups.

"Over 200 years ago, botanists on major Spanish expeditions to Peru named a new orchid Masdevallia because of the flower's similarity to monsterly creatures like dragons and bats," says Lorena Endara of the University of Florida in Gainesville. "Carlyle Luer, who later segregated Dracula from Masdevallia, sees these orchids as little bats flying in the forest since the flower faces down and the triangular sepals and the long sepaline tails display parallel to the ground."

"Some of the flies attracted to Dracula are new species, and I am presently working on descriptions of them," says Grimaldi. "I wanted to call this paper 'Dracula as Lord of the Flies,' but my co-authors convinced me to use the title 'Lord of the Flies: Pollination of Dracula orchids.'"

The paper, published in the orchid journal Lankesteriana, presents over 700 hours of observational data on flowers in Ecuadorian cloud forest where fruit flies were seen mating in (and hence pollinating) Dracula orchids. In addition to Endara and Grimaldi, Bitty Roy of the University of Oregon authored the paper; the research was funded by the National Science Foundation, the National Geographic Society, and other institutions.

Goblin SpidersOver the past three years, Platnick and colleagues have named or redefined the taxonomy of hundreds of new species of goblin spiders -- an often overlooked group named for their unusual appearance and secretive habits. Goblin spiders (members of the family Oonopidae) are extremely small: the largest is 3 millimeters in size, and most are under 2 millimeters.
"Goblins are probably the most poorly known group of spiders," says Platnick.

"Their small size has made them difficult to study, but scanning electron microscopy and recent advances in digital imaging are allowing us to examine their structures in much more detail than was previously possible."

A recently published Bulletin of the American Museum of Natural History unravels the previous taxonomy of the genus Stenoonops, a group of spineless goblin spiders that have a soft abdomen and muddy-orange carapace. Fourteen of the 19 species moved to new genera (in fact, six different genera). But because 17 new species from the Caribbean were described as Stenoonops, the genus increased in numbers and now has 23 species. Two other genera are given new species as well: Longoonops and Australoonops gain five species combined.

"It isn't surprising that there are so many undescribed goblin spiders," says Platnick. "When we began the global inventory of the Oonopidae, there were only about 500 species known, a number we thought represented about 20 percent of the actual biodiversity in this group. There are a lot of species that have small ranges -- the perfect group for giving us hints about the biogeographic histories of the areas they occupy, as well as for conservation, by showing us what areas are most in need of protection against habitat destruction."

In addition to Platnick, Nadine Dupérré is an author of this paper. The research was funded by the National Science Foundation and the American Museum of Natural History.


This is a Goblin spider Australoonops granulatus from Africa. (Credit: AMNH)

Saturday, January 8, 2011

New Species of Carnivorous Plant Discovered in Cambodia

A new species of carnivorous pitcher plant has been found by Fauna & Flora International (FFI) in Cambodia's remote Cardamom Mountains. The discovery of Nepenthes holdenii is an indicator of both the stunning diversity and lack of research in the forests of the Cardamom Mountains.

The large red and green pitchers that characterize Nepenthes holdenii are actually modified leaves designed to capture and digest insects. The pitchers can reach up to 30 centimeters long. The carnivorous strategy allows the plants to gain additional nutrients and flourish in otherwise impoverished soils.





A further unusual adaptation seen in this new species is its ability to cope with fire and extended periods of drought. Cambodia's dry season causes forests to desiccate and forest fires are common. Nepenthes holdenii exploits the clearings caused by these regular blazes by producing a large underground tuber which sends up a new pitcher- bearing vine after the fires have passed.
British photographer Jeremy Holden, who first found the plant on the FFI survey and after whom it is named, said: "The Cardamom Mountains are a treasure chest of new species, but it was a surprise to find something as exciting and charismatic as an unknown pitcher plant."



This discovery is the latest in a series of new species described from the Cardamom Mountains, including a green-blooded frog and a number of new reptiles. Jenny Daltry, FFI Senior Conservation Biologist said: "The flora of Cambodia is still poorly known and potentially holds many new species for researchers to discover."

François Mey, the French botanist and Nepenthes expert who described the plant said: "This amazing species may be the most drought-tolerant of the genus. Thanks to a large underground tuber, it has the ability to endure extended periods of drought and fires."

Francois Mey and Jeremy Holden are currently working on a book devoted to the carnivorous plants of Cambodia.


Nepenthes holdenii with Francois Mey. (Credit: Jeremy Holden)

Lice DNA Study Shows Humans First Wore Clothes 170,000 Years Ago.

Principal investigator David Reed, associate curator of mammals at the Florida Museum of Natural History on the UF campus, studies lice in modern humans to better understand human evolution and migration patterns. His latest five-year study used DNA sequencing to calculate when clothing lice first began to diverge genetically from human head lice.

Funded by the National Science Foundation, the study is available online and appears in this month's print edition of Molecular Biology and Evolution.



"We wanted to find another method for pinpointing when humans might have first started wearing clothing," Reed said. "Because they are so well adapted to clothing, we know that body lice or clothing lice almost certainly didn't exist until clothing came about in humans."

The data shows modern humans started wearing clothes about 70,000 years before migrating into colder climates and higher latitudes, which began about 100,000 years ago. This date would be virtually impossible to determine using archaeological data because early clothing would not survive in archaeological sites.


The study also shows humans started wearing clothes well after they lost body hair, which genetic skin-coloration research pinpoints at about 1 million years ago, meaning humans spent a considerable amount of time without body hair and without clothing, Reed said.

"It's interesting to think humans were able to survive in Africa for hundreds of thousands of years without clothing and without body hair, and that it wasn't until they had clothing that modern humans were then moving out of Africa into other parts of the world," Reed said.

Lice are studied because unlike most other parasites, they are stranded on lineages of hosts over long periods of evolutionary time. The relationship allows scientists to learn about evolutionary changes in the host based on changes in the parasite.

Applying unique data sets from lice to human evolution has only developed within the last 20 years, and provides information that could be used in medicine, evolutionary biology, ecology or any number of fields, Reed said.
"It gives the opportunity to study host-switching and invading new hosts -- behaviors seen in emerging infectious diseases that affect humans," Reed said.
A study of clothing lice in 2003 led by Mark Stoneking, a geneticist at the Max Planck Institute in Leipzig, Germany, estimated humans first began wearing clothes about 107,000 years ago. But the UF research includes new data and calculation methods better suited for the question.

"The new result from this lice study is an unexpectedly early date for clothing, much older than the earliest solid archaeological evidence, but it makes sense," said Ian Gilligan, lecturer in the School of Archaeology and Anthropology at The Australian National University. "It means modern humans probably started wearing clothes on a regular basis to keep warm when they were first exposed to Ice Age conditions."

The last Ice Age occurred about 120,000 years ago, but the study's date suggests humans started wearing clothes in the preceding Ice Age 180,000 years ago, according to temperature estimates from ice core studies, Gilligan said. Modern humans first appeared about 200,000 years ago.

Because archaic hominins did not leave descendants of clothing lice for sampling, the study does not explore the possibility archaic hominins outside of Africa were clothed in some fashion 800,000 years ago. But while archaic humans were able to survive for many generations outside Africa, only modern humans persisted there until the present.

"The things that may have made us much more successful in that endeavor hundreds of thousands of years later were technologies like the controlled use of fire, the ability to use clothing, new hunting strategies and new stone tools," Reed said.

Study co-authors were Melissa Toups of Indiana University and Andrew
Kitchen of The Pennsylvania State University, both previously with UF. Co-author Jessica Light of Texas A&M University was formerly a post-doctoral fellow at the Florida Museum. The researchers completed the project with the help of Reed's NSF Faculty Early Career Development Award, which is granted to researchers who exemplify the teacher-researcher .



In this photo taken Nov. 4, 2010, University of Florida researcher David Reed is lead investigator on a five-year study following the evolution of lice that found modern humans first began wearing clothes about 170,000 years ago, a technology which enabled them to successfully migrate out of Africa. Reed, assistant curator of mammals at the Florida Museum of Natural History on the UF campus, is pictured in front of the museum's "Northwest Florida: Waterways and Wildlife" exhibit. The loose-fitting clothing worn by Native Americans depicted in the exhibit is similar to garments lice would have first inhabited about 170,000 years ago. (Credit: Photo by Jeff Gage, Florida Museum of Natural History)

Friday, January 7, 2011

Longstanding Mystery of Sun's Hot Outer Atmosphere Solved

 One of the most enduring mysteries in solar physics is why the Sun's outer atmosphere, or corona, is millions of degrees hotter than its surface.

Now scientists believe they have discovered a major source of hot gas that replenishes the corona: jets of plasma shooting up from just above the Sun's surface.

The finding addresses a fundamental question in astrophysics: how energy is moved from the Sun's interior to create its hot outer atmosphere.

"It's always been quite a puzzle to figure out why the Sun's atmosphere is hotter than its surface," says Scott McIntosh, a solar physicist at the High Altitude Observatory of the National Center for Atmospheric Research (NCAR) in Boulder, Colo., who was involved in the study.

"By identifying that these jets insert heated plasma into the Sun's outer atmosphere, we can gain a much greater understanding of that region and possibly improve our knowledge of the Sun's subtle influence on the Earth's upper atmosphere."

The research, results of which are published in the journal Science, was conducted by scientists from Lockheed Martin's Solar and Astrophysics Laboratory (LMSAL), NCAR, and the University of Oslo. It was supported by NASA and the National Science Foundation (NSF), NCAR's sponsor.
"These observations are a significant step in understanding observed temperatures in the solar corona," says Rich Behnke of NSF's Division of Atmospheric and Geospace Sciences, which funded the research.

"They provide new insight about the energy output of the Sun and other stars. The results are also a great example of the power of collaboration among university, private industry and government scientists and organizations."
The research team focused on jets of plasma known as spicules, which are fountains of plasma propelled upward from near the surface of the Sun into the outer atmosphere.

For decades scientists believed spicules could send heat into the corona. However, following observational research in the 1980s, it was found that spicule plasma did not reach coronal temperatures, and so the theory largely fell out of vogue.

"Heating of spicules to millions of degrees has never been directly observed, so their role in coronal heating had been dismissed as unlikely," says Bart De Pontieu, the lead researcher and a solar physicist at LMSAL.
In 2007, De Pontieu, McIntosh, and their colleagues identified a new class of spicules that moved much faster and were shorter-lived than the traditional spicules.

These "Type II" spicules shoot upward at high speeds, often in excess of 100 kilometers per second, before disappearing.

The rapid disappearance of these jets suggested that the plasma they carried
might get very hot, but direct observational evidence of this process was missing.

The researchers used new observations from the Atmospheric Imaging Assembly on NASA's recently launched Solar Dynamics Observatory and NASA's Focal Plane Package for the Solar Optical Telescope (SOT) on the Japanese Hinode satellite to test their hypothesis.

"The high spatial and temporal resolution of the newer instruments was crucial in revealing this previously hidden coronal mass supply," says McIntosh.

"Our observations reveal, for the first time, the one-to-one connection between plasma that is heated to millions of degrees and the spicules that insert this plasma into the corona."

The findings provide an observational challenge to the existing theories of coronal heating.

During the past few decades, scientists proposed a wide variety of theoretical models, but the lack of detailed observation significantly hampered progress.
"One of our biggest challenges is to understand what drives and heats the material in the spicules," says De Pontieu.

A key step, according to De Pontieu, will be to better understand the interface region between the Sun's visible surface, or photosphere, and its corona.

Another NASA mission, the Interface Region Imaging Spectrograph (IRIS), is scheduled for launch in 2012 to provide high-fidelity data on the complex processes and enormous contrasts of density, temperature and magnetic field between the photosphere and corona. Researchers hope this will reveal more about the spicule heating and launch mechanism.

The LMSAL is part of the Lockheed Martin Space Systems Company, which designs and develops, tests, manufactures and operates a full spectrum of advanced-technology systems for national security and military, civil government and commercial customers.


Narrow jets of material, called spicules, streak upward from the Sun's surface at high speeds. (Credit: NASA)

Thursday, January 6, 2011

Prehistoric Bird Used Club-Like Wings as Weapon.

Paleontologists at Yale University and the Smithsonian Institution have discovered that Xenicibis, a member of the ibis family that lived about ten thousand years ago and was found only in Jamaica, most likely used its specialized wings like a flail, swinging its upper arm and striking its enemies with its thick hand bones.

"No animal has ever evolved anything quite like this," said Nicholas Longrich of Yale, who led the research. "We don't know of any other species that uses its body like a flail. It's the most specialized weaponry of any bird I've ever seen."
As part of the new study, the researchers analyzed a number of recently discovered partial skeletons of Xenicibis and found that the wings were drastically different from anything they'd seen before. "When I first saw it, I assumed it was some sort of deformity," Longrich said. "No one could believe it was actually that bizarre."

The bird, which was the size of a large chicken, is anatomically similar to other members of the ibis family except for its wings, which include thick, curved hand bones unlike those of any other known bird. Xenicibis also had a much larger breastbone and longer wings than most flightless birds. "That was our first clue that the wings were still being used for something," Longrich said.
While other birds are known to punch or hammer one another with their wings, Xenicibis is the only known animal to have used its hands, hinged at the wrist joint, like two baseball bats to swing at and strike its opponents. Although modern day ibises do not strike one another in this fashion, they are very territorial, with mates often fighting other pairs over nesting and feeding rights.
It's also possible that the birds used their club-like wings to defend themselves against other species that might have preyed on the birds' eggs or young. Xenicibis is unusual in that it became flightless even in the midst of a number of predators, including the Jamaican yellow boa, a small extinct monkey and over a dozen birds of prey.

The team found that two of the wing bones in the collection showed evidence of combat, including a fractured hand bone and a centimeter-thick upper arm bone that was broken in half. The damage is proof of the extreme force the birds were able to wield with their specialized wings, Longrich said.


The prehistoric Xenicibis used its wings like two clubs hinged at the wrist joint in order to swing at and attack one another. (Credit: Nicholas Longrich/Yale University)

'Nanoscoops' Could Spark New Generation of Electric Automobile Batteries.

An entirely new type of nanomaterial developed at Rensselaer Polytechnic Institute could enable the next generation of high-power rechargeable lithium (Li)-ion batteries for electric automobiles, as well as batteries for laptop computers, mobile phones, and other portable devices.

The new material, dubbed a "nanoscoop" because its shape resembles a cone with a scoop of ice cream on top, can withstand extremely high rates of charge and discharge that would cause conventional electrodes used in today's Li-ion batteries to rapidly deteriorate and fail. The nanoscoop's success lies in its unique material composition, structure, and size.

The Rensselaer research team, led by Professor Nikhil Koratkar, demonstrated how a nanoscoop electrode could be charged and discharged at a rate 40 to 60 times faster than conventional battery anodes, while maintaining a comparable energy density. This stellar performance, which was achieved over 100 continuous charge/discharge cycles, has the team confident that their new technology holds significant potential for the design and realization of high-power, high-capacity Li-ion rechargeable batteries.

"Charging my laptop or cell phone in a few minutes, rather than an hour, sounds pretty good to me," said Koratkar, a professor in the Department of Mechanical, Aerospace, and Nuclear Engineering at Rensselaer. "By using our nanoscoops as the anode architecture for Li-ion rechargeable batteries, this is a very real prospect. Moreover, this technology could potentially be ramped up to suit the demanding needs of batteries for electric automobiles."

Batteries for all-electric vehicles must deliver high power densities in addition to high energy densities, Koatkar said. These vehicles today use supercapacitors to perform power-intensive functions, such as starting the vehicle and rapid acceleration, in conjunction with conventional batteries that deliver high energy density for normal cruise driving and other operations. Koratkar said the invention of nanoscoops may enable these two separate systems to be combined into a single, more efficient battery unit.

Results of the study were detailed in the paper "Functionally Strain-Graded Nanoscoops for High Power Li-Ion Battery Anodes," published Thursday by the journal Nano Letters.

The anode structure of a Li-ion battery physically grows and shrinks as the battery charges or discharges. When charging, the addition of Li ions increases the volume of the anode, while discharging has the opposite effect. These volume changes result in a buildup of stress in the anode. Too great a stress that builds up too quickly, as in the case of a battery charging or discharging at high speeds, can cause the battery to fail prematurely. This is why most batteries in today's portable electronic devices like cell phones and laptops charge very slowly -- the slow charge rate is intentional and designed to protect the battery from stress-induced damage.

The Rensselaer team's nanoscoop, however, was engineered to withstand this buildup of stress. Made from a carbon (C) nanorod base topped with a thin layer of nanoscale aluminum (Al) and a "scoop" of nanoscale silicon (Si), the structures are flexible and able to quickly accept and discharge Li ions at extremely fast rates without sustaining significant damage. The segmented structure of the nanoscoop allows the strain to be gradually transferred from the C base to the Al layer, and finally to the Si scoop. This natural strain gradation provides for a less abrupt transition in stress across the material interfaces, leading to improved structural integrity of the electrode.
The nanoscale size of the scoop is also vital since nanostructures are less prone to cracking than bulk materials, according to Koratkar.

"Due to their nanoscale size, our nanoscoops can soak and release Li at high rates far more effectively than the macroscale anodes used in today's Li-ion batteries," he said. "This means our nanoscoop may be the solution to a critical problem facing auto companies and other battery manufacturers -- how can you increase the power density of a battery while still keeping the energy density high?"

A limitation of the nanoscoop architecture is the relatively low total mass of the electrode, Koratkar said. To solve this, the team's next steps are to try growing longer scoops with greater mass, or develop a method for stacking layers of nanoscoops on top of each other. Another possibility the team is exploring includes growing the nanoscoops on large flexible substrates that can be rolled or shaped to fit along the contours or chassis of the automobile.
Along with Koratkar, authors on the paper are Toh-Ming Lu, the R.P. Baker Distinguished Professor of Physics and associate director of the Center for Integrated Electronics at Rensselaer; and Rahul Krishnan, a graduate student in the Department of Materials Science and Engineering at Rensselaer.



Researchers at Rensselaer Polytechnic Institute developed an entirely new type of nanomaterial that could enable the next generation of high-power rechargeable lithium (Li)-ion batteries for electric automobiles, laptop computers, mobile phones, and other devices. The material, called a “nanoscoop” because it resembles a cone with a scoop of ice cream on top, is shown in the above scanning electron microscope image. Nanoscoops can withstand extremely high rates of charge and discharge that would cause today’s Li-ion batteries to rapidly deteriorate and fail. (Credit: Image courtesy of Rensselaer Polytechnic Institute)

Tuesday, January 4, 2011

The Ecosystem Engineer: Research Looks at Beavers' Role in River Restoration.

Beavers are often called ecosystem engineers because they can radically alter stream or valley bottom ecosystems, said Melinda Daniels, an associate professor of geography who recently studied the connection between beavers and river restoration. Beaver dams create diverse river landscapes, she said, and can turn a single-thread channel stream into a meadow, pond or multichannel, free-flowing stream.

"Our argument is that the restoration target for streams with forested riparian zones has got to acknowledge the diversity brought to river systems by active beaver populations," Daniels said.
Daniels and three researchers from the University of Connecticut co-authored

"The River Discontinuum: Applying Beaver Modifications to Baseline Conditions for Restoration of Forested Headwaters." The article, led by Denise Burchsted at the University of Connecticut, appears in a recent issue of BioScience, the journal of the American Institute of Biological Sciences.
While the research involves observations of several watersheds in northeastern Connecticut, the results are applicable to any forested stream, which typically have large beaver populations. Beaver populations have rebounded in recent years, Daniels said, after coming close to extinction in the early 19th century by hunters for their fur.

The ultimate goal of the research, Daniels said, is to help restore rivers in an efficient way that acknowledges ecosystem diversity and doesn't destroy it.
"A lot of rivers are in trouble and need work and restoration, but it's amazing how little we know about the systems we're trying to fix," she said. "We know they're broken, but we don't exactly know what they should look like because we know so little about how many of our river systems function."

Current restoration projects often don't consider the role of beavers as ecosystem engineers, and instead focus on creating continuous free-flowing streams, Daniels said. Such restoration can be expensive because it usually involves completely tearing down small 19th-century milldams and re-engineering an entire valley bottom.

Rather than tear down the whole milldam and radically change the surrounding ecosystem, the researchers recommend river restorers only remove part of it. This allows some ponded water to remain and mimics the role of beavers. Daniels said that in many cases if an old dam breaks and forms a gap, beavers may build their own dam to patch the gap and recreate the ecosystem that previously existed.

The researchers plan to continue river observations and collect more data to provide river restorers with insight for maintaining river ecosystem diversity.
"You can use these natural analogs to produce an ecosystem that looks a lot more like the one that was there before the colonists arrived," Daniels said. "We can restore rivers in a way that mimics the naturally diverse beaver streams, and we can save a lot of money in the process."


Beaver, cutting down a large oak tree. When engineers restore rivers, one Kansas State University professor hopes they'll keep a smaller engineer in mind: the North American beaver. (Credit: iStockphoto/Steve Greer)

Mariana Crow Will Go Extinct in 75 Years, Study Suggests

Researchers from the University of Washington say the Mariana crow, a forest crow living on Rota Island in the western Pacific Ocean, will go extinct in 75 years.

The extinction could happen almost twice as soon as previously believed.
The crow's extinction can be prevented with a bird management program that focuses on helping fledgling birds reach their first birthday, said James Ha, UW research associate professor in psychology.

Ha examined survival rates in 97 Mariana crows -- Corvus kubaryi -- that had been tracked between 1990 and 2010 by researchers. He found that 40 percent of fledgling crows made it to their first birthday.
The rapid decline of young birds is twice what researchers previously estimated.

"It's the first year of survival that's the most crucial," said Ha, lead author of a report on the research. "If only 40 percent of fledglings survive their first year, then we predict the species will go extinct in 75 years."

Ha and his co-authors published the report in the current issue of Bird Conservation International.

The 75-year extinction estimate is according to a population model that factors in the estimated number of existing Mariana crows -- 330 -- with the 40 percent first-year survival rate, average number of fledglings per nest and fertility of female birds. Using this model, Ha found that 91 birds would exist in 20 years and that in 75 years the species would be extinct.

Previously, biologists believed that the first-year survival rate of Mariana crows was higher, around 60 to 80 percent.

When Ha used those estimates in his population model, the outlook was not as grim for the birds. At 60 percent first-year survival rate, Mariana crows would dwindle to 218 birds in 20 years and become extinct in 133 years. And an 80 percent first-year survival rate projects that in 20 years there would be 453 birds, a growing population that would avoid extinction.

"According to the population model, if we can boost fledgling survival from 40 percent to 70 percent, the Mariana crows will be fine," Ha said.
Of the about 35 crow species, Mariana crows are considered rare and classified as critically endangered. Weighing about a half of a pound, Mariana crows are 40 percent smaller than other crows, such as the Northwest crow.

Monogamously-mating, Mariana crows live exclusively on Rota Island, populated by about 1,200 people and located 56 miles northeast of Guam. Rota is a U.S. territory and is up for consideration as a U.S. national park.
Ha and Renee Ha, co-author of the report and UW research scientist in psychology, fear that Rota faces the same avian demise as Guam, which has no
forest birds.

Brown tree snakes introduced to the island after World War II wiped out native birds, such as the Guam flycatcher and the Rufous fantail.
The Has suspect that the uncontrolled increase of feral cats on Rota is leading to the decrease of Mariana crows, much like brown tree snakes led to the disappearance of forest birds on Guam.

The researchers say that a captive rearing program could save the Mariana crows. They hope to set up a rearing facility where they could incubate eggs from the wild, raise the fledglings until their first birthday and then release the grown birds into nesting sites on the island.

The study was funded by the Commonwealth of the Northern Mariana Islands and the U.S. Fish and Wildlife Service. Co-author Alyssa Butler graduated from UW with a bachelor's degree in biology and is now a staff member at the Pali Institute, a science education camp in California.


This is a fledgling Mariana crow. (Credit: Sarah Faegre)

Sunday, January 2, 2011

New Hot Jupiter-Like Exoplanet Discovered.

A Qatar astronomer teamed with scientists at the Harvard-Smithsonian Center for Astrophysics (CfA) and other institutions to discover a new alien world. This "hot Jupiter," now named Qatar-1b, adds to the growing list of alien planets orbiting distant stars.

The Qatar exoplanet survey hunts for stars that "wink," dimming slightly every time an orbiting planet creates a "mini-eclipse" by crossing in front of the star as seen from Earth. Transit searches like this must sift through thousands of stars to find the small fraction with detectable planets. The complex observations and analysis create perfect opportunities for teamwork.
To find the new world, Qatar's wide-angle cameras (located in New Mexico) took images of the sky every clear night beginning in early 2010. The photographs then were transmitted to the UK for analysis by collaborating astronomers at St. Andrews and Leicester Universities and Qatar. That analysis narrowed the field to a few hundred candidate stars.

The Harvard-Smithsonian team, with Dr. Al Subai, followed up on the most promising candidates, making spectroscopic observations with the 60-inch-diameter telescope at the Smithsonian's Whipple Observatory in Arizona. Such observations can weed out binary-star systems with grazing eclipses, which mimic planetary transits. They also measured the stars' dimming more accurately with Whipple's 48-inch telescope.

The resulting data confirmed the existence of a planet now called Qatar-1b, orbiting an orange Type K star 550 light-years away. Qatar-1b is a gas giant 20 percent larger than Jupiter in diameter and 10 percent more massive. It belongs to the "hot Jupiter" family because it orbits 2.2 million miles from its star -- only six stellar radii away. The planet roasts at a temperature of around 2,000 degrees Fahrenheit.

Qatar-1b circles its star once every 1.4 days, meaning that its "year" is just 34 hours long. It's expected to be tidally locked with the star, so one side of the planet always faces the star. As a result, the planet spins on its axis once every 34 hours -- three times slower than Jupiter, which rotates once in 10 hours.



The newly-discovered alien world Qatar-1b orbits an orange type K star 550 light-years from Earth. Qatar-1b is a gas giant 20 percent larger than Jupiter in diameter and 10 percent more massive. It circles its star once every 1.4 days, meaning that its "year" is just 34 hours long. (Credit: David A. Aguilar (CfA))

Saturday, January 1, 2011

Tsunami Risk Higher in Los Angeles, Other Major Cities Than Thought, Haiti Study Suggests.

Like Haiti's capital, these cities all lie near the coast and near an active geologic feature called a strike-slip fault where two tectonic plates slide past each other like two hands rubbing against each other.

Until now, geologists did not consider the tsunami risk to be very high in these places because when these faults rupture, they usually do not vertically displace the seafloor much, which is how most tsunamis are generated. This latest research suggests even a moderate earthquake on a strike-slip fault can generate tsunamis through submarine landslides, raising the overall tsunami risk in these places.

"The scary part about that is you do not need a large earthquake to trigger a large tsunami," said Matt Hornbach, research associate at The University of Texas at Austin's Institute for Geophysics and lead author on a paper describing the research in the Oct. 10 online edition of the journal Nature Geoscience.

"Organizations that issue tsunami warnings usually look for large earthquakes on thrust faults," said Hornbach. "Now we see you don't necessarily need those things. A moderate earthquake on a strike-slip fault can still be cause for alarm."

Within minutes after the magnitude 7 Haiti earthquake, a series of tsunami waves, some as high as 9 feet (3 meters), crashed into parts of the shoreline. A few weeks later, a team of scientists from the U.S. and Haiti conducted geological field surveys of sites on and offshore near the quake's epicenter.
The scientists determined the tsunamis were generated primarily by weak sediment at the shore that collapsed and slid along the seafloor, displacing the overlying water. Combined with newly discovered evidence of historic tsunamis, the survey revealed a third of all tsunamis in the area are generated in this way. Geologists had previously estimated only about 3 percent of tsunamis globally are generated through submarine landslides.

"We found that tsunamis around Haiti are about 10 times more likely to be generated in this way than we would have expected," said Hornbach.
In addition to Hornbach, team members from The University of Texas at Austin include: Paul Mann, Fred Taylor, Cliff Frohlich, Sean Gulick and Marcy Davis. The team also includes researchers from Queens College, City University of New York; U.S. Geological Survey, University of Missouri; Lamont-Doherty Earth Observatory of Columbia University; University of California, Santa Barbara; Bureau of Mines and Energy (Haiti); and Universite d'Etat de Haiti.

The researchers gathered data on faults beneath the seafloor and land, vertical movement of the land, bathymetry (underwater topography) of the seafloor and evidence of tsunami waves. They worked on foot, on a small inflatable boat and on the 165-foot research vessel Endeavor.

This research was funded by a Rapid Response grant from the National Science Foundation and The University of Texas at Austin's Jackson School of Geosciences.

With additional funding from The Society for Geophysics' Geoscientists Without Borders program, Hornbach and others are now conducting a new research project in nearby Jamaica to assess the tsunami threat there.

"The geology of Kingston, Jamaica is nearly identical to Port Au Prince, Haiti," said Hornbach. "It's primed and ready to go and they need to prepare for it. The good news is, they have a leg up because they're aware of the problem."


Following the Jan. 12 Haiti earthquake, sediments near the town of Grand Goave slid into the sea, triggering a tsunami. Satellite images before (top left) and after (bottom left) show the location of the landslide. Seafloor bathymetry collected with sonar (right) reveals the slide path. (Credit: Image courtesy of University of Texas at Austin)

Friday, December 31, 2010

Why Some Plants Flower in Spring, Autumn and Some in Summer

A team of researchers from Warwick have isolated a gene responsible for regulating the expression of CONSTANS, an important inducer of flowering, in Arabidopsis.

'Being able to understand and ultimately control seasonal flowering will enable more predictable flowering, better scheduling and reduced wastage of crops', explained Dr Jackson.

Whilst the relationship between CONSTANS and flowering time in response to day length is well established, the mechanism controlling the expression of CONSTANS is still not fully understood.

The scientists present their work at the Society for Experimental Biology Annual Meeting in Prague.

Many plants control when they flower to coincide with particular seasons by responding to the length of the day, a process known as photoperiodism. A flowering mutant of Arabidopsis, which had an altered response to photoperiod, was used in the study led by Dr Stephen Jackson.

In the study funded by the BBSRC, the team identified the defective gene in the mutant plant that caused its abnormal flowering time.

They then cloned a working version of the gene, known as DAY NEUTRAL FLOWERING (DNF), from a normal Arabidopsis plant and introduced it into the mutant plant to restore its normal flowering response to day length.
The role of DNF in normal plant flowering is to regulate the CONSTANS gene. CONSTANS is activated only in the light and the plant is triggered to flower when CONSTANS levels rise above a certain threshold level during the daytime.

In normal plants, DNF represses the levels of CONSTANS until the day length is long enough and conditions are favourable for the survival of their seedlings. In mutant plants without an active DNF gene, CONSTANS is not repressed and they are able to flower earlier in the year, when days are still short.

The presence of the DNF gene has not yet been identified in species other than Arabidopsis but the scientists believe their on-going work may prove to have a wider significance for other species.
Scientists can override complex pathways that control flowering by artificially inducing or inhibiting key flowering genes such as DNF and CONSTANS. This can already be done in the laboratory by spraying an 'inducing agent' onto plants, stimulating them to flower early.

This could be used to extend the length of the harvesting season or to co-ordinate flowering or fruit production to a specific time. Growers already regulate the flowering of a few plants such as Chrysanthemum and Poinsettia, the latter specifically for Christmas and Easter.

Unravelling the complex pathways that control plant flowering will help scientists to understand and influence flowering patterns more effectively and in many different species.


In winter or early spring, Arabidopsis plants without an active DNF gene are already flowering (right). Those with the DNF gene will delay flowering until later in the year when days are longer and conditions are more favorable for survival of their seedlings (left). (Credit: Dr Steve Jackson)

Thursday, December 30, 2010

Bacteria Provide Example of One of Nature's First Immune Systems, Research Shows

His findings, which appear in Nature Communications, a multidisciplinary publication dedicated to research in all areas of the biological, physical and chemical sciences, shed light on how bacteria have throughout the course of millions of years developed resistance to antibiotics by co-opting the DNA of their natural enemies -- viruses.

The battle between bacteria and bacteria-eating viruses, Wood explains, has been going on for millions of years, with viruses attempting to replicate themselves by -- in one approach -- invading bacteria cells and integrating themselves into the chromosomes of the bacteria. When this happens a bacterium makes a copy of its chromosome, which includes the virus particle. The virus then can choose at a later time to replicate itself, killing the bacterium -- similar to a ticking time bomb, Wood says.

However, things can go radically wrong for the virus because of random but abundant mutations that occur within the chromosome of the bacterium. Having already integrated itself into the bacterium's chromosome, the virus is subject to mutation as well, and some of these mutations, Wood explains, render the virus unable to replicate and kill the bacterium.

With this new diverse blend of genetic material, Wood says, a bacterium not only overcomes the virus' lethal intentions but also flourishes at a greater rate than similar bacteria that have not incorporated viral DNA.
"Over millions of years, this virus becomes a normal part of the bacterium," Wood says. "It brings in new tricks, new genes, new proteins, new enzymes, new things that it can do. The bacterium learns how to do things from this.
"What we have found is that with this new viral DNA that has been trapped over millions of years in the chromosome, the cell has created a new immune system," Wood notes. "It has developed new proteins that have enabled it to resists antibiotics and other harmful things that attempt to oxidize cells, such as hydrogen peroxide. These cells that have the new viral set of tricks don't die or don't die as rapidly."

Understanding the significance of viral DNA to bacteria required Wood's research team to delete all of the viral DNA on the chromosome of a bacterium, in this case bacteria from a strain of E. coli. Wood's team, led by postdoctoral researcher Xiaoxue Wang, used what in a sense could be described as "enzymatic scissors" to "cut out" the nine viral patches, which amounted to precisely removing 166,000 nucleotides. Once the viral patches were successfully removed, the team examined how the bacterium cell changed. What they found was a dramatically increased sensitivity to antibiotics by the bacterium.

While Wood studied this effect in E. coli bacteria, he says similar processes have taken place on a massive, widespread scale, noting that viral DNA can be found in nearly all bacteria, with some strains possessing as much as 20 percent viral DNA within their chromosome.

"To put this into perspective, for some bacteria, one-fifth of their chromosome came from their enemy, and until our study, people had largely neglected to study that 20 percent of the chromosome," Wood says. "This viral DNA had been believed to be silent and unimportant, not having much impact on the cell.
"Our study is the first to show that we need to look at all bacteria and look at their old viral particles to see how they are affecting the bacteria's current ability to withstand things like antibiotics. If we can figure out how the cells are more resistant to antibiotics because of this additional DNA, we can perhaps make new, effective antibiotics."


Single gram-negative Escherichia coli bacterium. Studying how bacteria incorporate foreign DNA from invading viruses into their own regulatory processes, Thomas Wood, professor in the Artie McFerrin Department of Chemical Engineering at Texas A&M University, is uncovering the secrets of one of nature's most primitive immune systems. (Credit: Janice Haney Carr)

Wednesday, December 29, 2010

When the Black Hole Was Born: Astronomers Identify the Epoch of the First Fast Growth of Black Holes

Now a team of astronomers from Tel Aviv University, including Prof. Hagai Netzer and his research student Benny Trakhtenbrot, has determined that the era of first fast growth of the most massive black holes occurred when the universe was only about 1.2 billion years old -- not two to four billion years old, as was previously believed -- and they're growing at a very fast rate.
The results will be reported in a new paper soon to appear in The Astrophysical Journal.

The oldest are growing the fastest
The new research is based on observations with some of the largest ground-based telescopes in the world: "Gemini North" on top of Mauna Kea in Hawaii, and the "Very Large Telescope Array" on Cerro Paranal in Chile. The data obtained with the advanced instrumentation on these telescopes show that the black holes that were active when the universe was 1.2 billion years old are about ten times smaller than the most massive black holes that are seen at later times. However, they are growing much faster.

The measured rate of growth allowed the researchers to estimate what happened to these objects at much earlier as well as much later times. The team found that the very first black holes, those that started the entire growth process when the universe was only several hundred million years old, had masses of only 100-1000 times the mass of the sun. Such black holes may be related to the very first stars in the universe. They also found that the subsequent growth period of the observed sources, after the first 1.2 billion years, lasted only 100-200 million years.

The team found that the very first black holes -- those that started growing when the universe was only several hundred million years old -- had masses of only 100-1000 times the mass of the sun. Such black holes may be related to the very first stars in the universe. They also found that the subsequent growth period of these black holes, after the first 1.2 billion years, lasted only 100-200 million years.

The new study is the culmination of a seven year-long project at Tel Aviv University designed to follow the evolution of the most massive black holes and compare them with the evolution of the galaxies in which such objects reside.

Other researchers on the project include Prof. Ohad Shemmer of the University of North Texas, who took part in the earlier stage of the project as a Ph.D student at Tel Aviv University, and Prof. Paulina Lira, from the University of Chile.



Illustration of a black hole and its surrounding disk. (Credit: NASA)

Tuesday, December 28, 2010

The finding has implications for understanding future climate change because dust plays a significant role in controlling the amount of solar energy in the atmosphere. Depending on their size and other characteristics, some dust particles reflect solar energy and cool the planet, while others trap energy as heat.

"As small as they are, conglomerates of dust particles in soils behave the same way on impact as a glass dropped on a kitchen floor," Kok says. "Knowing this pattern can help us put together a clearer picture of what our future climate will look like."

The study may also improve the accuracy of weather forecasting, especially in dust-prone regions. Dust particles affect clouds and precipitation, as well as temperatures.

The research was supported by the National Science Foundation, which sponsors NCAR.

Shattered soil
Kok's research focused on a type of airborne particle known as mineral dust. These particles are usually emitted when grains of sand are blown into soil, shattering dirt and sending fragments into the air. The fragments can be as large as about 50 microns in diameter, or about the thickness of a fine strand of human hair.

The smallest particles, which are classified as clay and are as tiny as 2 microns in diameter, remain in the atmosphere for about a week, circling much of the globe and exerting a cooling influence by reflecting heat from the Sun back into space. Larger particles, classified as silt, fall out of the atmosphere after a few days. The larger the particle, the more it will tend to have a heating effect on the atmosphere.

Kok's research indicates that the ratio of silt particles to clay particles is two to eight times greater than represented in climate models.

Since climate scientists carefully calibrate the models to simulate the actual number of clay particles in the atmosphere, the paper suggests that models most likely err when it comes to the number of silt particles. Most of these larger particles swirl in the atmosphere within about 1,000 miles of desert regions, so adjusting their quantity in computer models should generate better projections of future climate in desert regions, such as the southwestern United States and northern Africa.

Additional research will be needed to determine whether future temperatures in those regions will increase more or less than currently indicated by computer models.

The study results also suggest that marine ecosystems, which draw down carbon dioxide from the atmosphere, may receive substantially more iron from airborne particles than previously estimated. The iron enhances biological activity, benefiting ocean food chains, including plants that take up carbon during photosynthesis.

In addition to influencing the amount of solar heat in the atmosphere, dust particles also get deposited on mountain snowpacks, where they absorb heat and accelerate melt.

Glass and dust: Common fracture patterns
Physicists have long known that certain brittle objects, such as glass or rocks, and even atomic nuclei, fracture in predictable patterns. The resulting fragments follow a certain range of sizes, with a predictable distribution of small, medium, and large pieces. Scientists refer to this type of pattern as scale invariance or self-similarity.

Physicists have devised mathematical formulas for the process by which cracks propagate in predictable ways as a brittle object breaks. Kok theorized that it would be possible to use these formulas to estimate the range of dust particle sizes. He turned to a 1983 study by Guillaume d'Almeida and Lothar Schüth from the Institute for Meteorology at the University of Mainz in Germany that measured the particle size distribution of arid soil.

By applying the formulas for fracture patterns of brittle objects to the soil measurements, Kok determined the size distribution of emitted dust particles. To his surprise, the formulas described measurements of dust particle sizes almost exactly.

"The idea that all these objects shatter in the same way is a beautiful thing, actually," Kok says. "It's nature's way of creating order in chaos."




Dust particles in the atmosphere range from about 0.1 microns to 50 microns in diameter (microns are also known as micrometers, abbreviated as µm). The size of dust particles determines how they affect climate and weather, influencing the amount of solar energy in the global atmosphere as well as the formation of clouds and precipitation in more dust-prone regions. The NASA satellite image in this illustration shows a 1992 dust storm over the Red Sea and Saudi Arabia. (Credit: Copyright UCAR)

Sunday, December 26, 2010

Ever-Sharp Urchin Teeth May Yield Tools That Never Need Honing

The rock-boring behavior is astonishing, scientists agree, but what is truly remarkable is that, despite constant grinding and scraping on stone, urchin teeth never, ever get dull. The secret of their ever-sharp qualities has puzzled scientists for decades, but now a new report by scientists from the University of Wisconsin-Madison and their colleagues has peeled back the toothy mystery.
Writing in the journal Advanced Functional Materials, a team led by UW-Madison professor of physics Pupa Gilbert describes the self-sharpening mechanism used by the California purple sea urchin to keep a razor-sharp edge on its choppers.

The urchin's self-sharpening trick, notes Gilbert, is something that could be mimicked by humans to make tools that never need honing.

"The sea urchin tooth is complicated in its design. It is one of the very few structures in nature that self-sharpen," says Gilbert, explaining that the sea urchin tooth, which is always growing, is a biomineral mosaic composed of calcite crystals with two forms -- plates and fibers -- arranged crosswise and cemented together with super-hard calcite nanocement. Between the crystals are layers of organic materials that are not as sturdy as the calcite crystals.
"The organic layers are the weak links in the chain," Gilbert explains. "There are breaking points at predetermined locations built into the teeth. It is a concept similar to perforated paper in the sense that the material breaks at these predetermined weak spots."

The crystalline nature of sea urchin dentition is, on the surface, different from other crystals found in nature. It lacks the obvious facets characteristic of familiar crystals, but at the very deepest levels the properties of crystals are evident in the orderly arrangement of the atoms that make up the biomineral mosaic teeth of the sea urchin.

To delve into the fundamental nature of the crystals that form sea urchin teeth, Gilbert and her colleagues used a variety of techniques from the materials scientist's toolbox. These include microscopy methods that depend on X-rays to illuminate how nanocrystals are arranged in teeth to make the sea urchins capable of grinding rock. Gilbert and her colleagues used these techniques to deduce how the crystals are organized and melded into a tough and durable biomineral.

Knowing the secret of the ever-sharp sea urchin tooth, says Gilbert, could one day have practical applications for human toolmakers. "Now that we know how it works, the knowledge could be used to develop methods to fabricate tools that could actually sharpen themselves with use," notes Gilbert. "The mechanism used by the urchin is the key. By shaping the object appropriately and using the same strategy the urchin employs, a tool with a self-sharpening edge could, in theory, be created."

The new research was supported by grants from the U.S. Department of Energy and the National Science Foundation. In addition to Gilbert, researchers from the University of California, Berkeley; Argonne National Laboratory; the Weizmann Institute of Science; and the Lawrence Berkeley National Laboratory contributed to the report.


Sea urchin teeth are pictured in situ. New research by Pupa Gilbert, a physics professor at the University of Wisconsin-Madison, and her colleagues reveals how the sea urchin's teeth are always sharp, despite constant grinding and scraping to create the nooks that protect the marine animal from predators and crashing waves. (Credit: Photo courtesy of Pupa Gilbert)

Big Quakes Trigger Small Quakes.

An earthquake in Alaska could trigger one near you, even if you're not in an earthquake-prone area, new research shows. Seismologists are now finding earthquakes in some unexpected places.

City Hall in Park City, Utah, is undergoing a $10 million seismic update. Park City is near the Wasatch Fault, an area overdue for an earthquake, so leaders have been concerned about earthquake-proofing the building for years. "It's something we absolutely expect," said Ron Ivie, a building official in Park City. "The question is, 'What day?'"

While earthquakes along fault lines are expected, seismologist Kris Pankow and her research team recently found slow-moving seismic surface waves, or L waves, from large earthquakes travel along the ground and trigger smaller earthquakes as they go.

"It's sort of like if a tree falls in the forest, does anyone hear it?" said Pankow, assistant director of the University of Utah seismic stations in Salt Lake City. "The same question was here: If the seismic waves go by everywhere, do they generate earthquakes everywhere?"

Unlike the earthquake risk in Park City, Pankow says the risk of these smaller earthquakes is minimal. The team tracked 15 large earthquakes and found 12 of them actually triggered smaller jolts. These are different than aftershocks because they happen miles away and sometimes hours or days later.

The team also found earthquakes in unlikely places like Canada, Australia and western Africa.

Pankow doesn't want to alarm anyone. She says the triggered earthquakes that have been observed have been small. Without a seismograph, you may not even notice them.

Seismologists still don't completely understand why earthquakes happen. Pankow and her team hope their work with these dynamically triggered earthquakes will help lead to an answer.

WHAT CAUSES EARTHQUAKES? An earthquake is the result of a sudden release of stored energy in the Earth's crust triggered by shifting tectonic plates. The Earth's lithosphere is an elaborate network of interconnected plates that move constantly -- far too slow for us to be aware of them, but moving, nonetheless. Occasionally they lock up at the boundaries, and this creates frictional stress. When that strain becomes too large, the rocks give way and break and slide along fault lines. This can give rise to a violent displacement of the Earth's crust, which we feel as vibrations or tremors as the pent-up energy is released. However, only 10% or so of the total energy is released in the seismic waves. However, the rest is converted into heat, used to crush and deform rock, or released as friction.

HOW DO SCIENTISTS RATE EARTHQUAKES? An earthquake's magnitude describes how much the ground moves. The scale is logarithmic, which means that when the magnitude increases by one (say from 3 to 4, or from 4 to 5) the amount of ground motion increases by ten times. That is, a magnitude 3 quake leads to ten times as much ground motion as a magnitude 2 quake, and a magnitude 2 leads to ten times as much motion as a magnitude 1. This means that a magnitude 3 is a hundred times as violent as a magnitude 1, and a hundred times less violent than a magnitude 5.

The magnitude scale also tells us just how much energy an earthquake released. For example, a magnitude 1 earthquake releases the same amount of energy as 30 pounds of TNT exploding. Although a magnitude 2 earthquake makes the ground move ten times as much as a magnitude 1, it releases 32 times as much energy -- or roughly as much as a ton of TNT. A magnitude 5 earthquake packs the punch of a moderate nuclear weapon, and a magnitude 12 quake would be enough to put a crack all the way through the center of the Earth.

Friday, December 24, 2010

System for Detecting Noise Pollution in the Sea and Its Impact on Cetaceans

In 2007, the Applied Bioacoustics Laboratory started work on a project called Listening to the Deep Ocean Environment (LIDO). It set out to record sounds on the seafloor and subsequently assess the extent to which artificial noises (maritime traffic, fishing, offshore facilities, military maneuvers, etc.) affect the quality of life of cetaceans in terms of any disorders they may suffer, or even their deaths.

Under the supervision of Michel André, the Applied Bioacoustics Laboratory (LAB) has now developed algorithms that automatically interpret these sounds, classify them in real time by their biological or anthropogenic origins and, within this division, the species of cetaceans present in the area analyzed are identified. Using the data obtained, it is possible to measure the extent to which noise pollution has an impact on the conservation of ecosystems.

This is the first system of its kind in the world and saves considerable analysis time and human resources in the detection and classification of noise, as these processes are completely automated. Thus, the technology prevents a continuous flow of unanalyzed acoustic data from overloading hard drives at research centers. Before now, this was one of the problems in processing uninterrupted data streams.

Finally, the acoustic signals and the result of the analysis can be listened to and seen live over a website that is available to the international scientific community and to laypersons

The importance of noise in the sea
There has always been natural and biological noise in the sea. However, the recent, uncontrolled introduction of artificial noise in the sea on an unprecedented scale poses an even greater threat to its equilibrium than any other source of pollution in the marine environment.

The sense of hearing is vital to cetaceans, as they use it to find prey, navigate in the sea, migrate and distinguish members of the same species. Therefore, their survival depends on their sense of hearing working properly.

Using a set of 13 hydrophones installed in over 10 underwater platforms located all over the world, the UPC's system detects the presence of cetaceans and enables scientists to study the relationship these animals have with other mammals in their habitat. This innovative system therefore opens unexplored avenues in the biological study of these species. However, the importance of the LIDO project lies in the possibility of better understanding the sensitivity of cetaceans to sources of noise pollution, detect the interaction of these animals with human activity and, more importantly, it will make it possible to take decisions for mitigating noise when the lives of these mammals are threatened.

To date, the increase in beached whales, sperm whales and other cetaceans around the world has been put down to the greater noise levels caused by fishing, sea trade, military maneuvers, and the construction of oilrigs and offshore wind farms. Thanks the technology developed by the UPC's research team, based on the Vilanova i la Geltrú Campus, it will now be possible to accurately ascertain whether there is a direct cause and effect relationship between the two events.

Based in this information, governments, institutions and businesses that operate in the sea will be able to establish response protocols to prevent these species from falling victim to exposure to noise of an anthropogenic origin that may cause damage to their hearing and, therefore, an imbalance in marine ecosystems.

First step for regulating noise pollution in the sea
The LAB has in fact written a manual of good practices for managing noise pollution in the sea at the request of the Ministry of the Environment and Rural and Marine Affairs, within the framework of the eCREM (Effects and Control of Anthropogenic Noise in Marine Ecosystems) project. The manual is the first step for drawing up a draft bill and good practices to regulate noise pollution in the sea in Spain, which is one of the first countries in the EU that intends to introduce regulations to this regard.

It should be taken into account that forecasts show that maritime traffic in the Mediterranean basin will increase significantly over the next few years to mitigate the atmospheric pollution derived from the transport of goods by road. The new EU directive on the sea rules that all member states must comply with a set of indicators for measuring marine noise pollution before 2012. A group of 11 experts from around Europe, one of whom is Michel André, the director of the LAB, are currently working to establish exactly which indicators are to be used.

The LAB has planned to develop alarm technologies in the near future. They are to be installed on various devices, such as autonomous buoys and underwater robots, which would send off warnings that cetaceans are approaching areas with high noise levels and set off response protocols.
The UPC team has devoted 15 years to the study of noise pollution in the sea and to the creation of technological solutions that make it possible to combine human activities and the interests of industry with the conservation of cetaceans and the marine environment.

The LAB is placing particular emphasis on the study of the effects of noise pollution on cetaceans because these marine mammals are at the top of the food chain, and their activities depend on the exchange of acoustic information. Therefore, their reaction to sources of noise pollution helps to determine the general state of marine environments. Cetaceans are considered to be bioindicators of the acoustic balance in oceans.

International network of underwater observatories
The LIDO platform, which records underwater noise in different parts of Europe and North America, is open to the international scientific community.
Noise sources are detected by hydrophones installed on over 10 underwater observatories. Some of the LIDO sensors have been deployed on the European Seafloor Observatory Network (ESONET), one of whose members is the UPC's Expandable Seafloor Observatory (OBSEA) located on the coast of Vilanova i la Geltrú. The LAB has another set of sensors installed in the deep sea infrastructures of the ANTARES project, an international collaboration that focuses on detecting subatomic particles called neutrinos, which move through space without being stopped by matter. Finally, there are another three hydrophones in North America on the seafloor platforms of the NEPTUNE network in Canada.

The LAB is in the final stages of reaching an agreement with Japan to install the technology on 17 platforms designed to detect the risk of earthquakes in the Asian archipelago.


Listening to the Deep Ocean Environment (LIDO) website. (Credit: Image courtesy of Universitat Politècnica de Catalunya)

Comprehensive Wind Info Collected to Improve Renewable Energy

"We know that the wind will blow, but the real challenge is to know when and how much," said atmospheric scientist Larry Berg. "This project takes an interesting approach -adapting an established technology for a new use -- to find a reliable way to measure winds and improve wind power forecasts."
Berg and Rob Newsom, both researchers at the Department of Energy's Pacific Northwest National Laboratory, are using a variety of meteorological equipment to measure winds high up into the air -- about 350 feet, the average height of turbine hubs -- and get a better reading on how winds behave up there.

Wind measurements are typically made much lower -- at about 30 feet high -- for weather monitoring purposes. Wind power companies do measure winds higher up, but that information is usually kept proprietary. PNNL's findings will be available to all online.

The study's findings could also provide more accurate wind predictions because of its field location -- a working wind farm. The equipment is being erected on and near a radio tower near the 300-megawatt Stateline Wind Energy Center, a wind power project that runs along the eastern Washington-Oregon border. Any wind power company could use the study's findings to improve how sites are chosen for wind farms and how those farms are operated.

The equipment started collecting measurements in November. Berg and Newsom will continue gathering measurements for about nine months, or through this summer. The period will allow the researchers to draw a more complete and accurate picture of how wind behaves at turbine height. The period represents the windiest months for the area.

"The goal here is to help everyone -- not just one group -- better understand wind's behavior and ultimately improve our use of it as a renewable power source," Newsom said.

Cool tools

But first researchers need to document wind behavior. To do that, they're
employing a handful of sophisticated meteorological tools.
One key instrument is the National Weather Service's NEXRAD Doppler radar weather station in Pendleton, Ore., about 19 miles south of Stateline. The station emits short pulses of radio waves that bounce back when they strike water droplets and other particles in the air. A national network of these stations is routinely used by television meteorologists to show clouds and precipitation in familiar, colorful digital maps. For this study, computers will analyze the returned signals to determine how the wind varies in the area around the radar, including the wind farm.

The team is also installing equipment specifically designed to measure wind speed and direction: a radar wind profiler. Like NEXRAD, the profiler sends out radio waves that are bounced back when it hits variations in moisture or temperature. But while NEXRAD scans the entire sky with its one rotating radar beam, the profiler sends three radar beams up into the sky. The profiler being used is part of the DOE's Atmospheric Radiation Measurement Climate Research Facility.

Another tool they're using is Doppler sodar, which uses sound instead of radio waves. A regular sequence of high-pitched beeps is sent into the sky and, like radar, will be reflected from variations in moisture and temperature. That information will help researchers measure winds that are at lower heights in the sky than the profiler can measure.

Finally, the researchers will install ultrasonic anemometers on the radio tower. The anemometer holds six tiny microphones, and measures the time it takes for sound pulses to travel from one microphone to another. Beyond measuring speed, the anemometer also helps determine wind direction. Combined, all this equipment will help researchers gain a more comprehensive understanding of how wind behaves at the turbine level of a working wind farm.

Improving renewable energy
Data collected during this study will be used to evaluate the performance of computer models of the atmosphere near the operating wind farm. These computer models are routinely used to provide weather forecasts of wind conditions hours and even days into the future. This information can help wind farms operate more efficiently and lets them better integrate the power they produce into the electric grid. These models are known to have relatively large errors in forecasting the severity and times of strong winds, including gusts during thunderstorms as fronts pass through an area. Even relatively small errors in wind speed predictions can lead to large errors in the predicted power outputs of wind farms.

When that happens, grid operators have to accommodate the influx of power, often by diverting or turning off other power sources. In the Pacific Northwest, that can mean spilling river water over hydroelectric dams instead of sending the water through the dams' power-producing turbines. Sometimes those diversions are needed on a moment's notice, when the grid becomes overwhelmed by unexpected windy weather. If such gusts could be reliably predicted ahead of time, power operators could make adequate plans beforehand. And when the wind stops blowing unexpectedly, the grid can experience a quick need for power.

Wind power companies could also use improved predictions to more wisely choose their wind farm sites. These companies invest heavily in understanding the wind characteristics of their sites before breaking ground, but forecasting turbine-level winds is still an evolving field.

As a result, two industrial partners are collaborating with Newsom and Berg on their research. 3TIER of Seattle, Wash., and WindLogics of St. Paul, Minn., both help wind power developers identify and evaluate potential locations for wind farms. They're serving as consultants and have provided input on what kind of data would be most helpful when examining wind sites.

If the NEXRAD wind data is verified by the data collected through the other meteorological equipment, the next step in this research would be to plug the NEXRAD data into a working weather model. The model could then be used to better predict future wind behavior. Using the data in a weather model is outside the scope of Berg and Newsom's current research, but they hope to be able to do so in the future.

Field work for the study began this month and will continue for about nine months. This study is funded by the DOE's Office of Energy Efficiency and Renewable Energy's Wind and Water Power Program and the Office of Science Atmospheric Radiation Measurement Facility.


Pacific Northwest National Laboratory scientists are researching how radar weather instruments can help improve predictions on when and how strongly winds will blow. They’re testing the instruments from a working wind farm in southeastern Washington State. (Credit: PNNL)