星空体育频道: 2013-05-26

2013年6月1日星期六

Innovative new nanotechnology stops bed bugs in their tracks -- literally

May 30, 2013 — Bed bugs now need to watch their step. Researchers at Stony Brook University have developed a safe, non-chemical resource that literally stops bed bugs in their tracks. This innovative new technology acts as a human-made web consisting of microfibers 50 times thinner than a human hair which entangle and trap bed bugs and other insects. This patent-pending technology is being commercialized by Fibertrap, a private company that employs non-toxic pest control methods.

The nanotech solution was developed at Stony Brook University's Center for Advanced Technology in Sensor Materials (Sensor CAT), a program funded by NYSTAR, as part of a statewide effort to encourage greater technological and economic collaboration between industry and research universities.

Miriam Rafailovich "Our nanotechnology produces entanglements that are millions of times more dense than woven products such as fabrics or carpets," said lead researcher Miriam Rafailovich, Distinguished Professor of Materials Science and Engineering and Co-Director in the Program of Chemical and Molecular Engineering at Stony Brook University. "The microfibers trap them by attaching to microstructures on their legs taking away their ability to move, which stops them from feeding and reproducing."

Successful tests were performed using live bed bugs and termites in Professor Rafailovich's lab with the assistance of Ying Liu, a scientist with Stony Brook University's Advanced Energy Research and Technology Center and Stony Brook graduate students Shan He and Linxi Zhang.

Kevin McAllister, Fibertrap's co-founder added, "We are very excited to move this advancement from the lab to the consumer. Our goal has always been to make a difference for people living in areas where bed bugs are pervasive and difficult to eradicate."

The microfibers are safe for humans and pets and unlike chemical treatments the insects cannot develop a resistance to it.

About Bed Bugs

Bed bugs (Cimex lectularius) are small, flat, parasitic insects that feed solely on the blood of people and animals while they sleep. Bed bugs are reddish-brown in color, wingless, range from one millimeter (mm) to seven mm (roughly the size of Lincoln's head on a penny), and can live several months without a blood meal.

Infestation

Bed bug infestations usually occur around or near the areas where people sleep. These areas include apartments, shelters, rooming houses, hotels, cruise ships, buses, trains and dorm rooms. They hide during the day in places such as seams of mattresses, box springs, bed frames, headboards, dresser tables, inside cracks or crevices, behind wallpaper or any other clutter or objects around a bed. Bed bugs have been shown to be able to travel over 100 feet in a night but tend to live within eight feet of where people sleep. A bed bug bite affects each person differently. Bite responses can range from an absence of any physical signs of the bite, to a small bite mark, to a serious allergic reaction. Bed bugs are not considered to be dangerous; however, an allergic reaction to several bites may need medical attention. (Source: Centers for Disease Control and Prevention) For more information please check out the Centers for Disease Control and Prevention Bed Bug FAQs.

Statistics

New York City consistently ranks in the top 10 or 15 cities with the worst bed bug problem across the nation. An annual list released by Orkin Pest Control based upon bed bug business in U.S. cities, lists Chicago as having the worst bed bug problem for 2012; New York City comes in at #10.

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Researchers coax clays to make human bone

The NDSU research team's 3-D mesh scaffold is composed of degradable materials that are compatible to human tissue. Over time, the cells generate bone and the scaffold deteriorates. As indicated in the NDSU team's published scientific research from 2008 to 2013, the nanoclays enhance the mechanical properties of the scaffold by enabling scaffold to bear load while bone generates. An interesting finding by the Katti group has shown that the nanoclays also impart useful biological properties to the scaffold.

"The biomineralized nanoclays also impart osteogenic or bone-forming abilities to the scaffold to enable birth of bone," said Dr. Kalpana Katti, Distinguished Professor of civil engineering at NDSU. "Although it would have been exciting to say that this finding had a 'Eureka moment,' this discovery was a methodical exploration of simulations and modeling, indicating that amino acid modified nanoclays are viable new nanomaterials," said Katti. The work was initially published in the Journal of Biomacromolecules in 2005. The current findings point toward the potential use of nanoclays for broader applications in medicine.

The NDSU's group most recent study in the Journal of Biomedical Materials Research Part A, published online Feb. 15, 2013, reports that nanoclays mediate human mesenchymal stem cell differentiation into bone cells and grow bone. The Katti research group uses amino acids, the building blocks of life, to modify clay structures and the modified nanoclays coax new bone growth. "Our current research studies underway involve the use of bioreactors that mimic fluid/blood flow in the human body during bone tissue regeneration," said Dr. Kalpana Katti.

The Katti group at NDSU has pioneered the use of nanoclays in bone regeneration since 2008, with research results appearing in Biomedical Materials, ASME Journal of Nanotechnology for Engineering and Medicine, Materials Science and Engineering C, along with the February 2013 publication in the Journal of Biomedical Materials Research Part A.

Bone tissue engineering represents important promise for regenerative medicine, according to Dr. Kalpana Katti. National Institutes of Health information shows that more than one million Americans have a hip or knee replaced each year. An aging population, in addition to orthopedic injuries of military veterans, and diseases such as osteoporosis and arthritis mean that the promise of scientific research to generate human bone could have far-reaching implications in the future.

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Satellites support drones in commercial airspace

A demonstration involved the deployment of a Heron-1 RPAS controlled by satellite for maritime surveillance applications offshore Spain. The project demonstrated the safe operation of RPAS in non-segregated airspace using satellite communications. Several partners, such as the GUCI (Spanish "Guardia Civil") and AENA (Aeropuertos Españoles y Navegación Aérea), supported the project.

The demonstration was part of the DeSIRE (Demonstration of Satellites enabling the Insertion of RPAS in Europe) initiative, an ESA-EDA (European Space Agency-European Defence Agency) project which includes European headquartered satellite operator SES, together with partners such as ThalesAleniaSpace and AT-one (an European Economic Interest Group consisting of Dutch Aerospace Laboratory NLR and German Aerospace Centre DLR). The initiative follows another ESA study (ESA SINUE) during which SES was already partnering with INDRA, the Spanish information technology and defense systems company.

Read the full story on EE Times Europe.

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2013年5月31日星期五

Intel wins CPU slot in Samsung tablet

LONDON – Samsung Electronics will use Atom-branded processors from Intel Corp. in a range of budget Android tablet computers, according to reports from Reuters and the Korea Times.

Samsung has chosen an Intel Clover Trail processor for at least one version of its Galaxy Tab 3 10.1, the Reuters report said. Clover Trial is a version of the Atom processor implemented in 32-nm CMOS.

The breakthrough by Intel into the mobile computing market is important for the company which has previously dominated personal computing but struggled to gain traction in the mobile sector. However, it is also unusual as Samsung is itself a developer and vendor of mobile processors, under the Exynos brand.

The Galaxy Tab 3 is expected to be unveiled at the Computex exhibition in Taiwan held during the first week of June.

Intel's design win was secured partly due to its willingness to offer favorable pricing and partly on its ability to provide resources to help with design work, according to the Korea Times report.

"Samsung wants to secure as many processors as possible at better pricing. That’s why Samsung Electronics has recently been diversifying its procurement channel in processor chips as a strategy to stabilize production yields of its in-house Exynos-branded processors," the Korea Times quoted a unnamed member of the Samsung research staff saying.

The same report cited an unnamed Intel Korea source saying that Intel had increased the number of chip engineers designing around the Atom processor from 6 to 50. "Most of them are working for Samsung-related projects with a mission to customize circuits for adaptation on Samsung products,” the report quoted the source saying.

Related links and articles:

Qualcomm leads smartphone processor market

London Calling: PowerVR confirmed in Samsung's 'Octa'

Intel chooses Dialog PMIC for 'Bay Trail' processor

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Analyst: Chip sales were weak in April

LONDON – The three-month average of global chip sales is likely to be reported at $23.5 billion for April, unchanged compared with March, according to Bruce Diesen, an analyst at Carnegie Group (Oslo, Norway).

The Semiconductor Industry Association usually reports the three-month average of global sales for April as compiled by the World Semiconductor Trade Statistics organization early in June.

Diesen's figure would represent seasonal weakness and Diesen put this down to a combination of factors. He said that the PC market has been particularly slow and Apple will have a slow second quarter in handsets. The weaker yen is also having a negative impact, he said.

"We recently cut our semiconductor sales [growth] estimate to minus 1 percent in 2013 from our old estimate of plus 5 percent," Diesen wrote in a report circulated Thursday (May 30).

The report said that Taiwanese technology-based exports flat and U.S. retail sales were soft in April. On the plus side global sales of automobiles improved in April and probably also in May.

Related links and articles:

Chip sales up 1 percent through Q1

Chip market starts year brightly

December dip caps weak year for chip sales

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Native Ohioans' speaking patterns help scientists decipher famous moon landing quote

Their results suggest that it is entirely possible that Armstrong said what he claimed, though evidence indicates that people are statistically more likely to hear "for man" instead of "for a man" on the recording.

The team will present its work at the 21st International Congress on Acoustics (ICA 2013), held June 2-7 in Montreal.

Armstrong was raised in central Ohio, where there is typically a lot of blending between words such as "for" and "a." "Prior acoustic analyses of Neil Armstrong's recording have established well that if the word 'a' was spoken, it was very short and was fully blended acoustically with the preceding word," says co-presenter Laura Dilley of Michigan State University. If Armstrong actually did say "a," she continues, it sounded something like "frrr(uh)." His blending of the two words, compounded with the poor sound quality of the transmission, has made it difficult for people to corroborate his claim that the "a" is there.

Dilley and her colleagues, who include MSU linguist Melissa Baese-Berk and OSU psychologist Mark Pitt, thought they might be able to figure out what Armstrong said with a statistical analysis of the duration of the "r" sound as spoken by native central Ohioans saying "for" and "for a" in natural conversation. They used a collection of recordings of conservational speech from 40 people raised in Columbus, Ohio, near Armstrong's native town of Wapakoneta. Within this body of recordings, they found 191 cases of "for a." They matched each of these to an instance of "for" as said by the same speaker and compared the relative duration. They also examined the duration of Armstrong's "for (a") from the lunar transmission.

The researchers found a large overlap between the relative duration of the "r" sound in "for" and "for a" using the Ohio speech data. The duration of the "frrr(uh)" in Armstrong's recording was 0.127 seconds, which falls into the middle of this overlap, though it is a slightly better match for an "a"-less "for." In other words, the researchers conclude, the lunar landing quote is highly compatible with either possible interpretation, though it is probably slightly more likely to be perceived as "for" regardless of what Armstrong actually said. Dilley says there may have been a "perfect storm of conditions" for the word "a" to have been spoken but not heard.

"We've bolstered Neil Armstrong's side of the story," she continues. "We feel we've partially vindicated him. But we'll most likely never know for sure exactly what he said based on the acoustic information."

Beyond shedding light on the famous quote, the work has implications for understanding how people perceive meaning in spoken language. "Every time we listen to speech and think we understand a sentence, we are performing a miraculous task, which is to take what is actually a continuous acoustic signal, break up that signal into somewhat arbitrary parts, and map those parts to our memories of all the words that we know in the language," Dilley says. "We need only look at computer speech recognition and how it succeeds and how it largely often fails to see how very difficult that problem is."

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Study coaxes clays to make human bone

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Biologists take snapshot of fleeting protein process

May 30, 2013 — Structural biologists from Rice University and Baylor College of Medicine (BCM) have captured the first three-dimensional crystalline snapshot of a critical but fleeting process that takes place thousands of times per second in each human cell. The research appears online today in the journal Cell Reports and could prove useful in the study of cancer and other diseases.

The biological "freeze-frame" shows the initial step in the formation of actin, a sturdy strand-like filament that is vital for humans. Actin filaments help cells maintain their shape. The filaments, which are called F-actin, also play key roles in muscle contraction, cell division and other critical processes.

"One of the major distinctions between cancerous cells and healthy cells is their shape," said study co-author Jianpeng Ma, professor of bioengineering at Rice and the Lodwick T. Bolin Professor of Biochemistry at BCM. "There is a correlation between healthy shape and well-regulated cell growth, and cancer cells are often ugly and ill-shaped compared to healthy cells."

F-actin was discovered in 1887, but despite the more than 18,000 actin-related studies in scientific literature, biologists have struggled to unlock some of its secrets. For example, F-actin is a polymer made of many smaller proteins called monomers. These building blocks, which are called G-actin, self-assemble end to end to form F-actin. But the self-assembly process is so efficient that scientists have been unable to see what happens when the first two or three monomers come together to form the nucleus of a filament. The F-actin filaments inside cells are constantly being built, torn apart and rebuilt.

"Nucleation is critical for this continual building and rebuilding," said BCM biochemist and study co-author Qinghua Wang. "For healthy cells, nucleation is the starting place for robust shape. For unhealthy cells, like cancer, nucleation processes may play a crucial role in unregulated growth. That's one reason we want to better understand nucleation."

In 2008, Ma and Wang asked Xiaorui Chen, a graduate student in BCM's Structural and Computational Biology and Molecular Biophysics program, to undertake the task of using x-ray crystallography to determine the structure of the actin nucleus. Her initial attempts failed, but the team finally hit upon the winning idea of creating two mutant versions of G-actin that could nucleate but not polymerize.

Native G-actin binds with one neighbor on top and one on bottom, and this top-bottom, end-to-end binding pattern is the key to forming long F-actin polymers. To foster nucleation without polymerization, Chen created two mutant versions of G-actin. One mutant could bind normally on top but not on bottom, and the other could bind normally on bottom but not on top.

"This dual-mutant strategy was the key," said Chen, who is now a postdoctoral researcher at BCM. "After that, we had to overcome problems related to forming and growing the crystal samples needed for crystallography."

Chen used a two-stage process to prepare the crystals. She first used high levels of super-saturation to spur initial crystal formation and then used a process called seeding to transfer the newly formed crystals to another medium where they could grow large enough for examination.

Once the crystals were prepared, they were analyzed with x-ray diffraction, which revealed the atomic arrangement of each atom in the nucleated, dual-mutant pair.

"We believe this dual-mutant arrangement reveals the most critical contacts involved in nucleation," Ma said. "For the first time, we are able to see how actin nucleation begins."

Additional co-authors include Fengyun Ni of both Rice and BCM, Xia Tian of BCM and Elena Kondrashkina of Northwestern University. The research was supported by the National Institutes of Health, the Gillson-Longenbaugh Foundation, the National Science Foundation, the Welch Foundation, the Department of Energy and the Michigan Economic Development Corp.

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Genetic variants linked to educational attainment

The study, which appears in the journal Science, was conducted by the Social Science Genetic Association Consortium (SSGAC), which includes researchers at NYU, Erasmus University, Cornell University, Harvard University, the University of Bristol, and the University of Queensland, among other institutions.

The SSGAC conducted what is called a genome-wide association study (GWAS) to explore the link between genetic variation and educational attainment -- the number of years of schooling completed by an individual and whether he or she graduated college. In a GWAS, researchers test hundreds of thousands of genetic markers for association with some characteristics such as a disease, trait or life outcome.

Because the sample included people from different countries -- where markers for schooling vary significantly -- the research team adopted the International Standard Classification of Education (ISCED) scale, which is a commonly used method for establishing a uniform measure of educational attainment across cohorts.

Anticipating that very large samples would be required to credibly detect genetic associations, the SSGAC researchers assembled a total sample size more than 10 times larger than any previous genetic study of any social-scientific outcome. The team examined associations between educational attainment and genetic variants called single-nucleotide polymorphisms, or SNPs, which are tiny changes at a single location in a person's genetic code.

The study found that the genetic markers with the strongest effects on educational attainment could each only explain two one-hundredths of a percentage point (0.02 percent). To put that figure into perspective, it is known from earlier research that the SNP with the largest effect on human height accounts for about 0.40 percent of the variation.

Combining the two million examined SNPs, the SSGAC researchers were able to explain about 2 percent of the variation in educational attainment across individuals, and anticipate that this figure will rise as larger samples become available.

"We hope that our findings will eventually be useful for understanding biological processes underlying learning, memory, reading disabilities and cognitive decline in the elderly," said co-author Daniel Benjamin, a behavioral economist at Cornell who is a co-director of the SSGAC.

"Another contribution of our study is that it will strengthen the methodological foundations of social-science genetics," said David Cesarini, an NYU assistant professor at the Center for Experimental Social Science and the Center for Neuroeconomics, who also co-directs the SSGAC. "We used 125,000 individuals to conduct this study. Previous studies used far smaller samples, sometimes as small as 100 individuals and rarely more than 10,000. These small samples make sense under the assumption that individual genes have large effects. However, if genes have small effects, as our study shows, then sample sizes need to be very large to produce robust findings that will reliably replicate in other samples."

The researchers were careful to note that they have not discovered "the gene for education" or that these findings somehow imply that a person's educational attainment is determined at birth.

"For most outcomes that we study as social scientists, genetic influences are likely to operate through environmental channels that are modifiable," explained NYU sociologist Dalton Conley, one of the study's co-authors who also serves on the Advisory Board of the SSGAC. "We have now taken a small but important first step toward identifying the specific genetic variants that predict educational attainment. Armed with this knowledge, we can now begin to examine how other factors -- including public policy, parental roles, and economic status -- dampen or amplify genetic effects and ultimately devise better remedies to bolster educational outcomes."

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One of the moon's mysteries solved: Origin of mascon basins

Large concentrations of mass lurk on the lunar surface hidden like coral reefs beneath the ocean waves -- an unseen and devastating hazard. These concentrations change the gravity field and can either pull a spacecraft in or push it off course, sealing its fate to a crash on the face of the moon.

"In 1968 these mass concentrations were an unwelcome discovery as scientists prepared for the Apollo landings, and they have remained a mystery ever since," said Jay Melosh, a member of the Gravity Recovery and Interior Laboratory, or GRAIL, science team who led the research. "GRAIL has now mapped where they lay, and we have a much better understanding of how they developed. If we return to the moon, we can now navigate with great precision."

A better understanding of these features also adds clues to the moon's origin and evolution and will be useful in studying other planets where mass concentrations also are known to exist including Mars and Mercury, said Melosh, who is a distinguished professor of earth, atmospheric and planetary sciences and physics.

"We now know the ancient moon must have been much hotter than it is now and the crust thinner than we thought," he said. "For the first time we can figure out what size asteroids hit the moon by looking at the basins left behind and the gravity signature of the areas. We now have tools to figure out more about the heavy asteroid bombardment and what the ancient Earth may have faced."

The team confirmed the standing theory that the concentrations of mass were caused by massive asteroid impacts billions of years ago and determined how these impacts changed the density of material on the moon's surface and, in turn, its gravity field. A paper detailing the results will be published online by the journal Science on May 30.

In addition to Melosh, Purdue team members include Andrew Freed, associate professor of earth, atmospheric and planetary sciences, and graduate students Brandon Johnson and David Blair. Additional team members include Maria Zuber, GRAIL principal investigator and professor at the Massachusetts Institute of Technology; J. Andrews-Hanna of the Colorado School of Mines; S. Solomon of Columbia University; and the GRAIL Science Team.

"The explanation of mascons has eluded scientists for decades," Zuber said. "Since their initial discovery they have also been observed on Mars and Mercury, and by understanding their formation on the moon we have greatly advanced knowledge of how major impacts modified planetary crusts."

The mass concentrations form a target pattern with a gravity surplus at the bulls-eye surrounded by a ring of gravity deficit and an outer ring of gravity surplus. The team found that this pattern arises as a natural consequence of crater excavation, collapse and cooling following an impact.

The team determined that the increase in density and gravitational pull at the bulls-eye was caused by lunar material melted from the heat of the asteroid impact. The melting causes the material to become more concentrated, stronger and denser, and pulls in additional material from the surrounding areas, Melosh said.

The large asteroid impacts also caused big holes into which the surrounding lunar material collapsed. As the cool, strong lunar crust slid into the holes it bent downward, forming a rigid, curved edge that held down the material beneath it and prevented it from fully rebounding to its original surface height. This causes a ring with less gravitational pull because the mass is held farther below the surface, the top of which is what most influences the gravitational signature, he said.

The outer ring of increased gravitational pull comes from the added mass of the material ejected by the initial impact that then piles on top of the lunar surface.

The team combined expertise in specialized computer analysis methods called hydrocodes and finite element codes to create computer simulations that could show the physical changes occurring from microseconds to millions of years. The team analyzed the Freundlich-Sharanov and Humorum mascon basins.

Melosh is a pioneer in adapting computer hydrocodes -- computer programs originally created to analyze the flow of liquids -- to simulate how complex materials move when high-speed collisions occur, like that of a planetary collision. Hydrocodes can be used to study such phenomena on a time scale of microseconds to hours, but are not practical from time scales much longer than that, he said.

Freed is a leader in adapting finite element codes, like those used to study car crashes, to simulate the changes in density of complex materials upon cooling and the evolution of Earth and other planets on the time scale of hours to millions of years.

Using the GRAIL data set, which offers an unprecedented, detailed map of the distribution of masses in the moon, the team was able to put together a picture of how the moon's crust and mantle behaved and the development of the concentrations of mass in the aftermath of large asteroid impacts.

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Pebbly rocks testify to old streambed on Mars

May 30, 2013 — Detailed analysis and review have borne out researchers' initial interpretation of pebble-containing slabs that NASA's Mars rover Curiosity investigated last year: They are part of an ancient streambed.

The rocks are the first ever found on Mars that contain streambed gravels. The sizes and shapes of the gravels embedded in these conglomerate rocks -- from the size of sand particles to the size of golf balls -- enabled researchers to calculate the depth and speed of the water that once flowed at this location.

"We completed more rigorous quantification of the outcrops to characterize the size distribution and roundness of the pebbles and sand that make up these conglomerates," said Rebecca Williams of the Planetary Science Institute, Tucson, Ariz., lead author of a report about them in the journal Science this week. "We ended up with a calculation in the same range as our initial estimate last fall. At a minimum, the stream was flowing at a speed equivalent to a walking pace -- a meter, or three feet, per second -- and it was ankle-deep to hip-deep."

Three pavement-like rocks examined with the telephoto capability of Curiosity's Mast Camera (Mastcam) during the rover's first 40 days on Mars are the basis for the new report. One, "Goulburn," is immediately adjacent to the rover's "Bradbury Landing" touchdown site. The other two, "Link" and "Hottah," are about 165 and 330 feet (50 and 100 meters) to the southeast. Researchers also used the rover's laser-shooting Chemistry and Camera (ChemCam) instrument to investigate the Link rock.

"These conglomerates look amazingly like streambed deposits on Earth," Williams said. "Most people are familiar with rounded river pebbles. Maybe you've picked up a smoothed, round rock to skip across the water. Seeing something so familiar on another world is exciting and also gratifying."

The larger pebbles are not distributed evenly in the conglomerate rocks. In Hottah, researchers detected alternating pebble-rich layers and sand layers. This is common in streambed deposits on Earth and provides additional evidence for stream flow on Mars. In addition, many of the pebbles are touching each other, a sign that they rolled along the bed of a stream.

"Our analysis of the amount of rounding of the pebbles provided further information," said Sanjeev Gupta of Imperial College, London, a co-author of the new report. "The rounding indicates sustained flow. It occurs as pebbles hit each other multiple times. This wasn't a one-off flow. It was sustained, certainly more than weeks or months, though we can't say exactly how long."

The stream carried the gravels at least a few miles, or kilometers, the researchers estimated.

The atmosphere of modern Mars is too thin to make a sustained stream flow of water possible, though the planet holds large quantities of water ice. Several types of evidence have indicated that ancient Mars had diverse environments with liquid water. However, none but these rocks found by Curiosity could provide the type of stream flow information published this week. Curiosity's images of conglomerate rocks indicate that atmospheric conditions at Gale Crater once enabled the flow of liquid water on the Martian surface.

During a two-year prime mission, researchers are using Curiosity's 10 science instruments to assess the environmental history in Gale Crater on Mars, where the rover has found evidence of ancient environmental conditions favorable for microbial life.

More information about Curiosity is online at: http://www.jpl.nasa.gov/msl , http://www.nasa.gov/msl and http://mars.jpl.nasa.gov/msl/ .

You can follow the mission on Facebook at: http://www.facebook.com/marscuriosity and on Twitter at http://www.twitter.com/marscuriosity .

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