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Inexpensive 'nano-camera' can operate at the speed of light

 

Device could be used in medical imaging, collision-avoidance detectors for cars, and interactive gaming

CAMBRIDGE, Mass -- A $500 "nano-camera" that can operate at the speed of light has been developed by researchers in the MIT Media Lab.

The three-dimensional camera, which was presented last week at Siggraph Asia in Hong Kong, could be used in medical imaging and collision-avoidance detectors for cars, and to improve the accuracy of motion tracking and gesture-recognition devices used in interactive gaming.

The camera is based on "Time of Flight" technology like that used in Microsoft's recently launched second-generation Kinect device, in which the location of objects is calculated by how long it takes a light signal to reflect off a surface and return to the sensor. However, unlike existing devices based on this technology, the new camera is not fooled by rain, fog, or even translucent objects, says co-author Achuta Kadambi, a graduate student at MIT.

"Using the current state of the art, such as the new Kinect, you cannot capture translucent objects in 3-D," Kadambi says. "That is because the light that bounces off the transparent object and the background smear into one pixel on the camera. Using our technique you can generate 3-D models of translucent or near-transparent objects."

In a conventional Time of Flight camera, a light signal is fired at a scene, where it bounces off an object and returns to strike the pixel. Since the speed of light is known, it is then simple for the camera to calculate the distance the signal has travelled and therefore the depth of the object it has been reflected from.

Unfortunately though, changing environmental conditions, semitransparent surfaces, edges, or motion all create multiple reflections that mix with the original signal and return to the camera, making it difficult to determine which is the correct measurement.

Instead, the new device uses an encoding technique commonly used in the telecommunications industry to calculate the distance a signal has travelled, says Ramesh Raskar, an associate professor of media arts and sciences and leader of the Camera Culture group within the Media Lab, who developed the method alongside Kadambi, Refael Whyte, Ayush Bhandari, and Christopher Barsi at MIT and Adrian Dorrington and Lee Streeter from the University of Waikato in New Zealand.

"We use a new method that allows us to encode information in time," Raskar says. "So when the data comes back, we can do calculations that are very common in the telecommunications world, to estimate different distances from the single signal."

The idea is similar to existing techniques that clear blurring in photographs, says Bhandari, a graduate student in the Media Lab. "People with shaky hands tend to take blurry photographs with their cellphones because several shifted versions of the scene smear together," Bhandari says. "By placing some assumptions on the model — for example that much of this blurring was caused by a jittery hand — the image can be unsmeared to produce a sharper picture."

The new model, which the team has dubbed nanophotography, unsmears the individual optical paths.

In 2011 Raskar's group unveiled a trillion-frame-per-second camera capable of capturing a single pulse of light as it travelled through a scene. The camera does this by probing the scene with a femtosecond impulse of light, then uses fast but expensive laboratory-grade optical equipment to take an image each time. However, this "femto-camera" costs around $500,000 to build.

In contrast, the new "nano-camera" probes the scene with a continuous-wave signal that oscillates at nanosecond periods. This allows the team to use inexpensive hardware — off-the-shelf light-emitting diodes (LEDs) can strobe at nanosecond periods, for example — meaning the camera can reach a time resolution within one order of magnitude of femtophotography while costing just $500.

"By solving the multipath problem, essentially just by changing the code, we are able to unmix the light paths and therefore visualize light moving across the scene," Kadambi says. "So we are able to get similar results to the $500,000 camera, albeit of slightly lower quality, for just $500."

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A new study in Nature Neuroscience has identified a region of the brain involved in decision-making.

Even a seemingly simple decision like whether to call heads or tails in a coin toss requires complex calculations by our brains. A new study in Nature Neuroscience has identified a region of the brain involved in decision-making. Researchers at the University of British Columbia newly identified a small region known as the lateral habenula, which had previously been linked to depression, that appears to be crucial to making cost-benefit calculations. The scientists trained a group of rats to choose between a small reward that was achieved consistently (one food pellet) and a larger reward (four pellets) that was obtained only occasionally. If the larger reward was received frequently enough, it would make sense to hold out for the four pellets; otherwise, it was better to go with the smaller reward. But when the researchers inactivated the lateral habenula, the rats were no longer able to make these calculations. Instead, they chose between the large and small rewards seemingly at random. The lateral habenula is one of the regions targeted by deep brain stimulation (DBS), and the researchers say the results of this study hint that DBS may not work to make people happier but to decrease the amount that they care about what makes them depressed.

Read more: http://bit.ly/InlmlV Journal article: What's better for me? Fundamental role for lateral habenula in promoting subjective decision biases. Nature Neuroscience, 2013. doi:10.1038/nn.3587 Image credit: Freddy The Boy/Flickr

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Stuck on flu

 

How a sugar-rich mucus barrier traps the virus -- and it gets free to infect

		IMAGE:   In this cartoon, experimental magnetic beads are coated with human or pig mucins (gray mesh), which are proteins containing sialic acids (red or blue diamonds), part of a protective mucus... Click here for more information.

Researchers at the University of California, San Diego School of Medicine have shown for the first time how influenza A viruses snip through a protective mucus net to both infect respiratory cells and later cut their way out to infect other cells.

The findings, published online today in Virology Journal by principal investigator Pascal Gagneux, PhD, associate professor in the Department of Cellular and Molecular Medicine, and colleagues, could point the way to new drugs or therapies that more effectively inhibit viral activity, and perhaps prevent some flu infections altogether.

Scientists have long known that common strains of influenza specifically seek and exploit sialic acids, a class of signaling sugar molecules that cover the surfaces of all animal cells. The ubiquitous H1N1 and H3N2 flu strains, for example, use the protein hemagglutinin (H) to bind to matching sialic acid receptors on the surface of a cell before penetrating it, and then use the enzyme neuraminidase (N) to cleave or split these sialic acids when viral particles are ready to exit and spread the infection.

Mucous membrane cells, such as those that line the internal airways of the lungs, nose and throat, defend themselves against such pathogens by secreting a mucus rich in sialic acids – a gooey trap intended to bog down viral particles before they can infect vulnerable cells.

"The sialic acids in the secreted mucus act like a sticky spider's web, drawing viruses in and holding them by their hemagglutinin proteins," said Gagneux.

Using a novel technique that presented viral particles with magnetic beads coated with different forms of mucin (the glycoproteins that comprise mucus) and varying known amounts of sialic acids, Gagneux and colleagues demonstrated that flu viruses counteract the natural barrier by also using neuraminidase to cut themselves free from binding mucosal sialic acids.

More notably, he said that by blocking neuraminidase activity in the mucus, the viruses remain stuck. "They can't release themselves from the mucus decoy and thus can't infect."

The discovery is likely to alter the way researchers and pharmaceutical companies think about how viruses and flu therapies function. Existing drugs like Tamiflu and Relenza inhibit neuraminidase activity and presumably dampen the ability of the flu virus to spread among cells. The work by Gagneux and colleagues suggests inhibiting neuraminidase activity in mucus may reduce the initial risk of infection.

The challenge will be to restrict neuraminidase inhibition to the mucus. Many types of cells in the human body produce neuraminidases, each performing vital cellular functions, particularly in the brain. Limiting neuraminidase inhibition to relevant mucus-secreting cells is necessary to reducing potential side effects.

"The airway's mucus layer is constantly being shed and renewed, within a couple of hours the entire layer is replaced by a new layer," said first author Miriam Cohen, PhD, an assistant project scientist in Gagneux's lab. "A drug or compound that slows down neuraminidase activity rather than completely inhibit its activity will suffice to enhance the natural protective effect of mucus and prevent infection."

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Co-authors include Hooman P. Senaati and Nissi M. Varki, Department of Cellular and Molecular Medicine, UCSD; Xing-Quan Zhang and Robert T. Schooley, Division of Infectious Disease, UCSD; Hui-Wen Chen, Division of Infectious Disease, UCSD and School of Veterinary Medicine, National Taiwan University.

Funding support for this study came, in part, from the University of California Laboratory Fees Research Program, The G. Harold and Leila Y. Mathers Charitable Foundation, the National Institute of Allergy and Infectious Diseases (1UO1A1074521), the National Institute of Neurological Disorders and Stroke (P30 NS047101) and UC San Diego Cancer Center Specialize Support grant P30 CA23100.

Research Paves Path for Hybrid Nano-Materials That Could Replace Human Tissue or Today's Pills

 

 

Brooklyn, New York—A team of researchers has uncovered critical information that could help scientists understand how protein polymers interact with other self-assembling biopolymers. The research helps explain naturally occurring nano-material within cells and could one day lead to engineered bio-composites for drug delivery, artificial tissue, bio-sensing, or cancer diagnosis.

Results of this study, “Bionanocomposites: Differential Effects of Cellulose Nanocrystals on Protein Diblock Copolymers,” were recently published in the American Chemical Society’s BioMacromolecules. The findings were the result of a collaborative research project from the Polytechnic Institute of New York University (NYU-Poly) Montclare Lab for Protein Engineering and Molecular Design under the direction of Associate Professor of Chemical and Biomolecular Engineering Jin K. Montclare.

Bionanocomposites provide a singular area of research that incorporates biology, chemistry, materials science, engineering, and nanotechnology. Medical researchers believe they hold particular promise because—unlike the materials that build today’s medical implants, for example—they are biodegradable and biocompatible, not subject to rejection by the body’s immune defenses. As biocomposites rarely exist isolated from other substances in nature, scientists do not yet understand how they interact with other materials such as lipids, nucleic acids, or other organic materials and on a molecular level. This study, which explored the ways in which protein polymers interact with another biopolymer, cellulose, provides the key to better understanding how biocomposite materials would interact with the human body for medical applications.

The materials analyzed were composed of bioengineered protein polymers and cellulose nanocrystals and hold promise for medical applications including non-toxic, targeted drug delivery systems. Such bionanocomposites could also be used as scaffolding for tissue growth, synthetic biomaterials, or an environmentally friendly replacement for petroleum-derived polymers currently in use.

Lead author of the paper is Jennifer S. Haghpanah, at the time a doctoral candidate at NYU-Poly and now at Columbia University. Collaborators in addition to Haghpanah and Montclare include Raymond Tu, City College of New York Department of Chemical Engineering; Sandra Da Silva, National Institute of Standards and Technology (NIST) Biomaterials and Biosystems Division; Deng Yan, NYU Langone School of Medicine Skirball Institute of Biomolecular Medicine, Microscopy Core Facilities; Silvana Mueller, Christoph Weder, and E. Johan Foster, all of the University of Fribourg Adolphe Merkle Institute; and Iulia Sacui and Jeffery W. Gilman, NIST Materials Science and Engineering Division.

Research in the Montclare Lab explores engineering macromolecules that will assist in applications such as tissue engineering, drug-delivery, imaging, and energy, with the long-term goal of being able to predictably design or engineer artificial therapeutics, biocatalysts, scaffolds, and cells.

This research was funded in part by the National Science Foundation, the Society of Plastics Engineers, the Swiss National Science Foundation, and the Adolphe-Merkle Foundation.  

Study looks at better prediction for epileptic seizures through adaptive learning approach

 

 

Thursday, November 21, 2013

 

Media Contact: Herb Booth, Office:817-272-7075, Cell:214-546-1082, [email protected]

News Topics: computer science, engineering, research

A UT Arlington assistant engineering professor has developed a computational model that can more accurately predict when an epileptic seizure will occur next based on the patient’s personalized medical information.

Shouyi Wang, assistant professor of Industrial and Manufacturing Systems Engineering

The research conducted by Shouyi Wang, an assistant professor in the Department of Industrial and Manufacturing Systems Engineering, has been in the paper “Online Seizure Prediction Using an Adaptive Learning Approach” in IEEE Transactions on Knowledge and Data Engineering.

Wang’s model analyzes electroencephalography, or EEG, readings from an individual, to predict future seizures. Early warnings could lead a patient to use medicine to combat an oncoming seizure, he said.

“The challenge with seizure prediction has been that every epileptic is different. Some patients suffer several seizures a day. Others will go several years without experiencing a seizure,” Wang said. “But if we use the EEG readings to build a personalized data profile, we’re better able to understand what’s happening to that person.”

Epilepsy is one of the most common neurological disorders, characterized by recurrent seizures. Epilepsy and seizures affect nearly 3 million Americans at an estimated annual cost of $17.6 billion in direct and indirect costs, according to the national Epilepsy Foundation,  About 10 percent of the American population will experience a seizure in their lifetime, the agency says.

Wang teamed with Wanpracha Art Chaovalitwongse of the University of Washington and Stephen Wong of the Rutgers Robert Wood Johnson Medical School for the research.

Wang said early indications are that the new computational model could provide 70 percent accuracy or better and give a prediction horizon of about 30 minutes before the actual seizure would occur.

The current model collects data through a cap embedded with EEG wires. Wang’s team is working to develop a less obtrusive EEG cap that will record and transmit readings to a box for easy data download or transmission.

Victoria Chen, professor and chairwoman of the Industrial and Manufacturing Systems Engineering Department, said Wang’s work in the area of bioinformatics offers hope for the many people who suffer from epilepsy.

“This computational model might be used to predict other life-threatening episodes of diseases,” Chen said.

Wang said his model builds upon an adaptive learning framework and is capable of achieving more and more accurate prediction performance for each individual patient by collecting more and more personalized medical data.

“As a society, we’ve gotten really good at looking at the big picture,” Wang said. “We can tell you the likelihood of suffering a heart attack if you’re over a certain age, of a certain weight and if you smoke. But we have only started to personalize that data for individuals who are all different.”

Wang’s work is representative of excellence at The University of Texas at Arlington, a comprehensive research institution of more than 33,300 students and 2,200 faculty members in the epicenter of North Texas. It is the second largest institution in The University of Texas System. Total research expenditures reached almost $78 million last year. Visit www.uta.edu to learn more.

Staphylococcus aureus bacteria turns immune system against itself

 

 

Around 20 percent of all humans are persistently colonized with Staphylococcus aureus bacteria, a leading cause of skin infections and one of the major sources of hospital-acquired infections, including the antibiotic-resistant strain MRSA.

University of Chicago scientists have recently discovered one of the keys to the immense success of S. aureus—the ability to hijack a primary human immune defense mechanism and use it to destroy white blood cells. The study was published Nov 15 in Science.

"These bacteria have endowed themselves with weapons to not only anticipate every immune defense, but turn these immune defenses against the host as well," said Olaf Schneewind, MD, PhD, professor and chair of the Department of Microbiology at the University of Chicago and senior author of the paper.

One of the first lines of defense in the human immune response are neutrophils, a type of white blood cell that ensnares invaders in neutrophil extracellular traps (NETs), a web-like structure of DNA and proteins. Captured bacteria are then destroyed by amoeba-like white blood cells known as macrophages. However, S. aureus infection sites are often marked by an absence of macrophages, indicating the bacteria somehow defend themselves against the immune system.

To reveal how these bacteria circumvent the human immune response, Schneewind and his team screened a series of S. aureus possessing mutations that shut down genes thought to play a role in infection. They looked to see how these mutated bacteria behaved in live tissue, and identified two strains that were unable to avoid macrophage attack. When these mutations—to the staphylococcal nuclease (nuc) and adenosine synthase A (adsA) genes respectively—were reversed, infection sites were free of macrophages again.

Looking for a mechanism of action, the researchers grew S. aureus in a laboratory dish alongside neutrophils and macrophages. The white blood cells were healthy in this environment and could clear bacteria. But the addition of a chemical to stimulate NET formation triggered macrophage death. Realizing that a toxic product was being generated by S. aureus in response to NETs, the team used high performance liquid chromatography and mass spectrometry techniques to isolate the molecule.

They discovered that S. aureus were converting NETs into 2'-deoxyadenosine (dAdo), a molecule which is toxic to macrophages. This effectively turned NETs into a weapon against the immune system.

"Sooner or later almost every human gets some form of S. aureus infection. Our work describes for the first time the mechanism that these bacteria use to exclude macrophages from infected sites," Schneewind said. "Coupled with previously known mechanisms that suppress the adaptive immune response, the success of these organisms is almost guaranteed."

S. aureus bacteria are found on the skin or in the respiratory tracts of colonized humans and commonly cause skin infections in the form of abscesses or boils. Normally not dangerous, severe issues arise when the bacteria enter the bloodstream, where they can cause diseases such as sepsis and meningitis. Antibiotic-resistant strains, such as methicillin-resistant S. aureus (MRSA), are difficult to treat and have plagued healthcare systems around the world.

Schneewind and his team hope to leverage their findings toward therapies against S. aureus infections. But both genes and the dAdo molecule are closely related to important human physiological mechanisms, and Schneewind believes targeting these in bacteria, without harming human function, could be difficult.

"In theory you could build inhibitors of these bacterial enzymes or remove them," Schneewind said. "But these are untested waters and the pursuit of such goal requires a lot more study."

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The study, "Staphylococcus aureus Degrades Neutrophil Extracellular Traps to Promote Immune Cell Death," was supported the National Institute of Allergy and Infectious Diseases and the American Heart Association. Additional authors include Vilasack Thammavongsa and Dominique M. Missiakas,

The semantics behind the sale price: When does the 'original' price matter?

 

 

Consumers love a sale. In fact, when asked what makes a sale appealing, most simply say, "The price was good." But this answer fails to acknowledge that subjective factors also contribute to the perceived value of a deal. According to new research published in the Journal of Consumer Research, it's possible to increase the perception of a good deal.

"We find that the more a consumer relies on the original price when trying to determine a product's worth, the more valuable they perceive the deal to be," write authors Christina Kan, Donald R. Lichtenstein (both University of Colorado), Susan Jung Grant (Boston University), and Chris Janiszewski (University of Florida). "If a retailer can get a consumer to pay more attention to a $179 original list price, and less attention to a $99 sale price, when assessing the worth of a winter jacket, then the $99 sale price will seem like a better deal."

The study research summarizes three situations in which list prices have more influence on the estimated worth of a product and, by extension, the perceived value of the deal. In three different experiments, the authors reveal that when a consumer focuses on competing product similarities, they are more likely to consider all of the available information when judging the worth of a product. That is, both the original list price and the sale price are used to determine the perceived worth of the product. In contrast, when a consumer focuses on product dissimilarities, the consumer is more likely to consider only the sale price when determining the subjective value of the product.

"This research provides insights for both retailers and consumers. Retailers can make a sales event more effective by encouraging the consumer to rely on the original price when assessing both the value of the product and the value of the deal. Additionally, by comparing product prices at competing retailers, consumers can lessen the impact of the original price on their assessment of the products' overall worth," the authors conclude.

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Christina Kan, Donald R. Lichtenstein, Susan Jung Grant, and Chris Janiszewski. "Strengthening the Influence of Advertised Reference Prices through Information Priming." Journal of Consumer Research: April 2014. For more information, contact Christina Kan ([email protected]) or visit http://ejcr.org/.

Chaotic physics in ferroelectrics hints at brain-like computing

 

 Unexpected behavior in ferroelectric materials explored by researchers at Oak Ridge National Laboratory supports a new approach to information storage and processing known as memcomputing. (hi-res image)

OAK RIDGE, Tenn., Nov. 18, 2013—Unexpected behavior in ferroelectric materials explored by researchers at the Department of Energy’s Oak Ridge National Laboratory supports a new approach to information storage and processing.

Ferroelectric materials are known for their ability to spontaneously switch polarization when an electric field is applied. Using a scanning probe microscope, the ORNL-led team took advantage of this property to draw areas of switched polarization called domains on the surface of a ferroelectric material. To the researchers’ surprise, when written in dense arrays, the domains began forming complex and unpredictable patterns on the material’s surface.

“When we reduced the distance between domains, we started to see things that should have been completely impossible,” said ORNL’s Anton Ievlev, the first author on the paper published in Nature Physics. “All of a sudden, when we tried to draw a domain, it wouldn’t form, or it would form in an alternating pattern like a checkerboard.  At first glance, it didn’t make any sense. We thought that when a domain forms, it forms. It shouldn’t be dependent on surrounding domains.” 

After studying patterns of domain formation under varying conditions, the researchers realized the complex behavior could be explained through chaos theory. One domain would suppress the creation of a second domain nearby but facilitate the formation of one farther away -- a precondition of chaotic behavior, says ORNL’s Sergei Kalinin, who led the study.

“Chaotic behavior is generally realized in time, not in space,” he said. ”An example is a dripping faucet: sometimes the droplets fall in a regular pattern, sometimes not, but it is a time-dependent process. To see chaotic behavior realized in space, as in our experiment, is highly unusual.”

Collaborator Yuriy Pershin of the University of South Carolina explains that the team’s system possesses key characteristics needed for memcomputing, an emergent computing paradigm in which information storage and processing occur on the same physical platform.

“Memcomputing is basically how the human brain operates: Neurons and their connections--synapses--can store and process information in the same location,” Pershin said. “This experiment with ferroelectric domains demonstrates the possibility of memcomputing.”

Encoding information in the domain radius could allow researchers to create logic operations on a surface of ferroelectric material, thereby combining the locations of information storage and processing.

The researchers note that although the system in principle has a universal computing ability, much more work is required to design a commercially attractive all-electronic computing device based on the domain interaction effect.

“These studies also make us rethink the role of surface and electrochemical phenomena in ferroelectric materials, since the domain interactions are directly traced to the behavior of surface screening charges liberated during electrochemical reaction coupled to the switching process,” Kalinin said.

The study is published as “Intermittency, quasiperiodicity, and chaos during scanning probe microscopy tip-induced ferroelectric domain switching,” and is available online. Coauthors are ORNL’s Stephen Jesse, Evgheni Strelcov, Sergei Kalinin and Amit Kumar; the National Academy of Sciences of Ukraine’s Anna Morozovska and Eugene Eliseev; the University of South Carolina’s Yuriy Pershin; and Ural Federal University’s Vladimir Shur. Ievlev, formerly of Ural Federal University, has joined ORNL as a postdoctoral fellow.

Part of this research was conducted at the Center for Nanophase Materials Sciences, which is sponsored at ORNL by the Scientific User Facilities Division in DOE’s Office of Basic Energy Sciences. CNMS is one of the five DOE Nanoscale Science Research Centers supported by the DOE Office of Science, premier national user facilities for interdisciplinary research at the nanoscale. Together the NSRCs comprise a suite of complementary facilities that provide researchers with state-of-the-art capabilities to fabricate, process, characterize and model nanoscale materials, and constitute the largest infrastructure investment of the National Nanotechnology Initiative. The NSRCs are located at DOE's Argonne, Brookhaven, Lawrence Berkeley, Oak Ridge and Sandia and Los Alamos national laboratories.  For more information about the DOE NSRCs, please visit http://science.energy.gov/bes/suf/user-facilities/nanoscale-science-research-centers/.

ORNL is managed by UT-Battelle for the Department of Energy's Office of Science. DOE's Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit http://science.energy.gov.

Media Contact: Morgan McCorkle
Oak Ridge National Laboratory
865-574-7308

Volcano discovered smoldering under a kilometer of ice in West Antarctica

 

Its heat may increase the rate of ice loss from one of the continent's major ice streams

		IMAGE:   Mount Sidley, at the leading edge of the Executive Committee Range in Marie Byrd Land is the last volcano in the chain that rises above the surface of the ice.... Click here for more information.

It wasn't what they were looking for but that only made the discovery all the more exciting.

In January 2010 a team of scientists had set up two crossing lines of seismographs across Marie Byrd Land in West Antarctica. It was the first time the scientists had deployed many instruments in the interior of the continent that could operate year-round even in the coldest parts of Antarctica.

Like a giant CT machine, the seismograph array used disturbances created by distant earthquakes to make images of the ice and rock deep within West Antarctica.

There were big questions to be asked and answered. The goal, says Doug Wiens, professor of earth and planetary science at Washington University in St. Louis and one of the project's principle investigators, was essentially to weigh the ice sheet to help reconstruct Antarctica's climate history. But to do this accurately the scientists had to know how the earth's mantle would respond to an ice burden, and that depended on whether it was hot and fluid or cool and viscous. The seismic data would allow them to map the mantle's properties.

In the meantime, automated-event-detection software was put to work to comb the data for anything unusual.

When it found two bursts of seismic events between January 2010 and March 2011, Wiens' PhD student Amanda Lough looked more closely to see what was rattling the continent's bones.

Was it rock grinding on rock, ice groaning over ice, or, perhaps, hot gases and liquid rock forcing their way through cracks in a volcanic complex?

Uncertain at first, the more Lough and her colleagues looked, the more convinced they became that a new volcano was forming a kilometer beneath the ice.

The discovery of the new as yet unnamed volcano is announced in the Nov. 17 advanced online issue of Nature Geoscience.

Following the trail of clues

The teams that install seismographs in Antarctica are given first crack at the data. Lough had done her bit as part of the WUSTL team, traveling to East Antarctica three times to install or remove stations in East Antarctica.

In 2010 many of the instruments were moved to West Antarctica and Wiens asked Lough to look at the seismic data coming in, the first large-scale dataset from this part of the continent.

"I started seeing events that kept occurring at the same location, which was odd, "Lough said. "Then I realized they were close to some mountains–but not right on top of them."

"My first thought was, 'Okay, maybe its just coincidence.' But then I looked more closely and realized that the mountains were actually volcanoes and there was an age progression to the range. The volcanoes closest to the seismic events were the youngest ones."

The events were weak and very low frequency, which strongly suggested they weren't tectonic in origin. While low-magnitude seismic events of tectonic origin typically have frequencies of 10 to 20 cycles per second, this shaking was dominated by frequencies of 2 to 4 cycles per second.

Ruling out ice

But glacial processes can generate low-frequency events. If the events weren't tectonic could they be glacial?

To probe farther, Lough used a global computer model of seismic velocities to "relocate" the hypocenters of the events to account for the known seismic velocities along different paths through the Earth. This procedure collapsed the swarm clusters to a third their original size.

It also showed that almost all of the events had occurred at depths of 25 to 40 kilometers (15 to 25 miles below the surface). This is extraordinarily deep—deep enough to be near the boundary between the earth's crust and mantle, called the Moho, and more or less rules out a glacial origin.

It also casts doubt on a tectonic one. "A tectonic event might have a hypocenter 10 to 15 kilometers (6 to 9 miles) deep, but at 25 to 40 kilometers, these were way too deep," Lough says.

A colleague suggested that the event waveforms looked like Deep Long Period earthquakes, or DPLs, which occur in volcanic areas, have the same frequency characteristics and are as deep. "Everything matches up," Lough says.

An ash layer encased in ice

The seismologists also talked to Duncan Young and Don Blankenship of the University of Texas who fly airborne radar over Antarctica to produce topographic maps of the bedrock. "In these maps, you can see that there's elevation in the bed topography at the same location as the seismic events," Lough says.

The radar images also showed a layer of ash buried under the ice. "They see this layer all around our group of earthquakes and only in this area," Lough says.

"Their best guess is that it came from Mount Waesche, an existing volcano near Mt Sidley. But that is also interesting because scientists had no idea when Mount Waesche was last active, and the ash layer is sets the age of the eruption at 8,000 years ago. "

What's up down there?

The case for volcanic origin has been made. But what exactly is causing the seismic activity?

"Most mountains in Antarctica are not volcanic," Wiens says, "but most in this area are. Is it because East and West Antarctica are slowly rifting apart? We don't know exactly. But we think there is probably a hot spot in the mantle here producing magma far beneath the surface."

"People aren't really sure what causes DPLs," Lough says. "It seems to vary by volcanic complex, but most people think it's the movement of magma and other fluids that leads to pressure-induced vibrations in cracks within volcanic and hydrothermal systems."

Will the new volcano erupt?

"Definitely," Lough says. "In fact because of the radar shows a mountain beneath the ice I think it has erupted in the past, before the rumblings we recorded.

Will the eruptions punch through a kilometer or more of ice above it?

The scientists calculated that an enormous eruption, one that released a thousand times more energy than the typical eruption, would be necessary to breach the ice above the volcano.

On the other hand a subglacial eruption and the accompanying heat flow will melt a lot of ice. "The volcano will create millions of gallons of water beneath the ice—many lakes full," says Wiens. This water will rush beneath the ice towards the sea and feed into the hydrological catchment of the MacAyeal Ice Stream, one of several major ice streams draining ice from Marie Byrd Land into the Ross Ice Shelf.

By lubricating the bedrock, it will speed the flow of the overlying ice, perhaps increasing the rate of ice-mass loss in West Antarctica.

"We weren't expecting to find anything like this," Wiens says

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This research was funded by the National Science Foundation, Division of Polar Programs.

Environmental toxins linked to heart defects

 

Abstract: 15332 (Hall F, Core 2, Poster Board: 2092)

Children's congenital heart defects may be associated with their mothers' exposure to specific mixtures of environmental toxins during pregnancy, according to research presented at the American Heart Association's Scientific Sessions 2013.

Congenital heart defects occur when the heart or blood vessels near the heart don't develop normally before birth. Defects may be caused by chromosomal abnormalities, but the cause is unknown in most cases.   

Researchers examined patterns of congenital heart defects incidence and presence of environmental toxicants in Alberta, Canada. The ongoing research seeks to determine if pregnant women's proximity to organic compounds and metals emitted in the air impacts the risk of heart defects in their children.

"Although still in the early stage, this research suggests some chemical emissions — particularly, industrial air emissions — may be linked to heart abnormalities that develop while the heart is forming in the womb," said lead researcher Deliwe P. Ngwezi, M.D., a Ph.D., student and research fellow in pediatric cardiology at the University of Alberta in Canada.

The study is based on congenital heart defects diagnosed in 2004-11 and chemical emissions recorded by a Canadian agency tracking pollutants.

Researchers looked at three chemical categories, but only one group showed a strong correlation with rates of congenital heart defects. According to Ngwezi, the group of chemicals consists of a mixture of organic compounds and metals namely: benzene, butadiene, carbon disulphide, chloroform, ethylene oxide, hexachlorobenzene, tetrachloroethane, methanol, sulphur dioxide, toluene, lead, mercury and cadmium.

Congenital heart defect rates have gradually decreased in Canada since 2006, which is about  the time the government tightened regulations to reduce industrial air emissions, Ngwezi said. The heart defect decreases were mainly associated with heart defects resulting in holes between the upper and lower heart chambers (septal defects) and malformations of the cardiac outflow tracts (conotruncal defects), according to Ngwezi. 

"For now, consumers and healthcare providers should be educated about the potential toll of pollutants on the developing heart," she said. "As we have observed in the preliminary results, when the emissions decrease, the rates of congenital heart defects also decrease." This study, she said, should draw attention to the increasing evidence about the impact of environmental pollution on birth defects. Limitations of the study include that researchers' observations were made at a group level, not according to individual risk and the self-reported industry data which is monitored and collected annually by government, according to Ngwezi. 

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Co-authors are Lisa K. Hornberger, M.D.; Brad Saretsky, B.Sc.; Sujata Chandra, M.D., M.Sc.; Deborah Fruitman, M.D., F.R.C.P.C.; and Alvaro Osornio-Vargas, M.D., Ph.D. Author disclosures are on the abstract.

The study was funded by the Women and Children's Health Research Institute, University of Alberta; Hamilton-Naki Foundation of South Africa; and an Emerging Research Team Grant from the University of Alberta's Faculty of Medicine and Dentistry and Alberta Health Services.

Learn more about Congenital Heart Defects.

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Note: Actual presentation time is from 3 p.m. CT/4 p.m. ET Sunday, Nov. 17, 2013.

Downloadable video/audio interviews, B-roll, animation and images related to this news release are on the right column of the release link at http://newsroom.heart.org/news/environmental-toxins-linked-to-heart-defects?preview=176456a4352eb666d9efa2edb9f0edf2. Video clips with researchers/authors of the studies will be added to the release link after embargo