Thursday, May 12, 2011

To combat soaring fuel prices and cut greenhouse gas emissions, the aviation industry is racing toward the use of biofuels. In 2008, Virgin Atlantic became the first commercial airline to fly a plane on a blend of biofuel and petroleum. Since then, Air New Zealand, Qatar Airways and Continental Airlines, among others, have passed biofuel test flights, and Lufthansa is racing to be the first carrier to run daily flights on a biofuel blend.

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However, researchers at MIT say the industry may want to make sure it has examined biofuels' complete carbon footprint before making an all-out push. They say that when a biofuel's origins are factored in — for example, taking into account whether the fuel is made from palm oil grown in a clear-cut rainforest — conventional fossil fuels may sometimes be the "greener" choice.

"What we found was that technologies that look very promising could also result in high emissions if done improperly," says James Hileman, principal research engineer in the Department of Aeronautics and Astronautics, who has published the results of a study conducted with MIT graduate students Russell Stratton and Hsin Min Wong in the online version of the journal Environmental Science and Technology. "You can't simply say a biofuel is good or bad — it depends on how it's produced and processed, and that's part of the debate that hasn't been brought forward."

Hileman and his team performed a life-cycle analysis of 14 fuel sources, including conventional petroleum-based jet fuel and "drop-in" biofuels: alternatives that can directly replace traditional fuels with little or no change to existing infrastructure or vehicles. In a previous report for the Federal Aviation Administration's Partnership for Air Transportation Noise and Emissions Reduction, they calculated the emissions throughout the life cycle of a biofuel, "from well to wake" — from acquiring the biomass to transporting it to converting it to fuel, as well as its combustion.

"All those processes require energy," Hileman says, "and that ends up in the release of carbon dioxide."

In the current Environmental Science and Technology paper, Hileman considered the entire biofuel life cycle of diesel engine fuel compared with jet fuel, and found that changing key parameters can dramatically change the total greenhouse gas emissions from a given biofuel.

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In particular, the team found that emissions varied widely depending on the type of land used to grow biofuel components such as soy, palm and rapeseed. For example, Hileman and his team calculated that biofuels derived from palm oil emitted 55 times more carbon dioxide if the palm oil came from a plantation located in a converted rainforest rather than a previously cleared area. Depending on the type of land used, biofuels could ultimately emit 10 times more carbon dioxide than conventional fuel.

"Severe cases of land-use change could make coal-to-liquid fuels look green," says Hileman, noting that by conventional standards, "coal-to-liquid is not a green option."

Hileman says the airline industry needs to account for such scenarios when thinking about how to scale up biofuel production. The problem, he says, is not so much the technology to convert biofuels: Companies like Choren and Rentech have successfully built small-scale biofuel production facilities and are looking to expand in the near future. Rather, Hileman says the challenge is in allocating large swaths of land to cultivate enough biomass, in a sustainable fashion, to feed the growing demand for biofuels.

He says one solution to the land-use problem may be to explore crops like algae and salicornia that don't require deforestation or fertile soil to grow. Scientists are exploring these as a fuel source, particularly since they also do not require fresh water.

Total emissions from biofuel production may also be mitigated by a biofuel's byproducts. For example, the process of converting jatropha to biofuel also yields solid biomass: For every kilogram of jatropha oil produced, 0.8 kilograms of meal, 1.1 kilograms of shells and 1.7 kilograms of husks are created. These co-products could be used to produce electricity, for animal feed or as fertilizer. Hileman says that this is a great example of how co-products can have a large impact on the carbon dioxide emissions of a fuel.

Hileman says his analysis is one lens through which policymakers can view biofuel production. In making decisions on how to build infrastructure and resources to support a larger biofuel economy, he says researchers also need to look at the biofuel life cycle in terms of cost and yield.

"We need to have fuels that can be made at an economical price, and at large quantity," Hileman says. "Greenhouse gases [are] just part of the equation, and there's a lot of interesting work going on in this field."

Provided by Massachusetts Institute of Technology (news : web)

Flipping hot Jupiters: Why some planets orbit the wrong way

The transiting giant planet orbits very close to the star and in a direction opposite to the stellar rotation. This peculiar configuration results from gravitational perturbations by another much more distant planet (upper left). Credit: Credit: Lynette Cook

(PhysOrg.com) -- In the last few years astronomers have observed that in some extrasolar systems the star is spinning one way and the planet, a "hot Jupiter," is orbiting the star in the opposite direction. A Northwestern University research team is the first to model how these huge planets got so close to their stars -- thanks to gravitational perturbations by a much more distant planet -- and how the planets' orbits can flip in the process.

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More than 500 extrasolar planets -- planets that orbit stars other than the sun -- have been discovered since 1995. But only in the last few years have astronomers observed that in some of these systems the star is spinning one way and the planet, a "hot Jupiter," is orbiting the star in the opposite direction.

"That's really weird, and it's even weirder because the planet is so close to the star," said Frederic A. Rasio, a theoretical astrophysicist at Northwestern University. "How can one be spinning one way and the other orbiting exactly the other way? It's crazy. It so obviously violates our most basic picture of planet andstar formation."

Figuring out how these huge planets got so close to their stars led Rasio and his research team to also explain their flipped orbits. Using large-scale computer simulations, they are the first to model how a hot Jupiter's orbit can flip and go in the direction opposite to the star's spin. Gravitational perturbations by a much more distant planet result in the hot Jupiter having both a "wrong way" and a very close orbit. (A hot Jupiter is a huge Jupiter-like planet in very close proximity to the central star.)

"Once you get more than one planet, the planets perturb each other gravitationally," Rasio said. "This becomes interesting because that means whatever orbit they were formed on isn't necessarily the orbit they will stay on forever. These mutual perturbations can change the orbits, as we see in these extrasolar systems."

Details of the study will be published May 12 by the journal Nature.

In explaining the peculiar configuration of an extrasolar system, the researchers also have added to our general understanding of planetary system formation and evolution and reflected on what their findings mean for the solar system.

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"We had thought our solar system was typical in the universe, but from day one everything has looked weird in the extrasolar planetary systems," Rasio said. "That makes us the odd ball really. Learning about these other systems provides a context for how special our system is. We certainly seem to live in a special place."

Rasio, a professor of physics and astronomy in Northwestern's Weinberg College of Arts and Sciences is the senior author of the paper. The first author is Smadar Naoz, a postdoctoral fellow at Northwestern and a Gruber Fellow.

The physics the research team used to solve the problem is basically orbital mechanics, Rasio said, the same kind of physics NASA uses to send satellites around the solar system.

"It was a beautiful problem," said Naoz, "because the answer was there for us for so long. It's the same physics, but no one noticed it could explain hot Jupiters and flipped orbits."

"Doing the calculations was not obvious or easy," Rasio said, "Some of the approximations used by others in the past were really not quite right. We were doing it right for the first time in 50 years, thanks in large part to the persistence of Smadar."

"It takes a smart, young person who first can do the calculations on paper and develop a full mathematical model and then turn it into a computer program that solves the equations," Rasio added. "This is the only way we can produce real numbers to compare to the actual measurements taken by astronomers."

In their model, the researchers assume a star similar to the sun, and a system with two planets. The inner planet is a gas giant similar to Jupiter, and initially it is far from the star, where Jupiter-type planets are thought to form. The outer planet is also fairly large and is farther from the star than the first planet. It interacts with the inner planet, perturbing it and shaking up the system.

The effects on the inner planet are weak but build up over a very long period of time, resulting in two significant changes in the system: the inner gas giant orbits very close to the star and its orbit is in the opposite direction of the central star's spin. The changes occur, according to the model, because the two orbits are exchanging angular momentum, and the inner one loses energy via strong tides.

The gravitational coupling between the two planets causes the inner planet to go into an eccentric, needle-shaped orbit. It has to lose a lot of angular momentum, which it does by dumping it onto the outer planet. The inner planet's orbit gradually shrinks because energy is dissipated through tides, pulling in close to the star and producing a hot Jupiter. In the process, the orbit of the planet can flip.

Only about a quarter of astronomers' observations of these hot Jupiter systems show flipped orbits. The Northwestern model needs to be able to produce both flipped and non-flipped orbits, and it does, Rasio said.

More information: "Hot Jupiters From Secular Planet–Planet Interactions" Nature (2011)

Provided by Northwestern University (news : web)

Immature skull led young Tyrannosaurs to rely on speed, agility to catch prey

Animation of the skull of a newly discovered juvenile specimen of the Mongolian tyrannosaur Tarbosaurus with the bones and some other anatomical structures labeled. The juvenile was only 2-3 years old when it died, providing insight into the growth and changing lifestyles of tyrannosaurs. Animation by Ridgely and Witmer, Courtesy of WitmerLab at Ohio University.
The different hunting strategies of juveniles and adults may have reduced competition among Tarbosaurus and strengthened their role as the dominant predators of their environment.
"The juvenile skull shows that there must have a change in dietary niches as the animals got older," Tsuihiji said. "The younger animals would have taken smaller prey that they could subdue without risking damage to their skulls, whereas the older animals and adults had progressively stronger skulls that would have allowed taking larger, more dangerous prey."

Enlarge
These are silhouettes of an adult Tarbosaurus and the newly discovered juvenile, along with a human for scale. Credit: Hayashibara Museum of Natural Sciences.
The late Cretaceous environment offered plenty of options for prey.
"Tarbosaurus is found in the same rocks as giant herbivorous dinosaurs like the long-necked sauropod Opisthocoelicaudia and the duckbill hadrosaur Saurolophus," said Mahito Watabe of the Hayashibara Museum of Natural Sciences in Okayama, who led the expedition to Mongolia in 2006 that uncovered the new skull. "But the young juvenile Tarbosaurus would have hunted smallerprey, perhaps something like the bony-headed dinosaur Prenocephale."
The juvenile skull also is important because it helps clarify the identity of small, potentially juvenile specimens of other tyrannosaur species previously found.
"The beauty of our new young skull is that we absolutely know for many good reasons that it's Tarbosaurus," Witmer said. "We can use this known growth series to get a better sense of whether some of these more controversial finds grew up to be Tarbosaurus, Tyrannosaurus or some other species."
Provided by Ohio University (news : web)

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Sneaky HIV virus found

Sneaky HIV virus found

Monday, 09 May 2011

The University of Melbourne
"These results show what a slippery customer the HIV virus is."
Image: skodonnell/iStockphoto
Latest insights into immunity to HIV could help to develop a vaccine to build antibodies’ defences against the disease, a University of Melbourne study has found.

By investigating the action of the human antibodies called ADCC, in people with HIV, researchers were able to identify that the virus evolves to evade or ‘escape’ the antibodies.

Professor Stephen Kent of the University of Melbourne and one of the senior authors on the paper said ADCC antibodies have been strongly implicated in protection from HIV in several vaccine trials but their action was poorly understood.

“These results show what a slippery customer the HIV virus is, but also shows that these ADCC antibodies are really forcing the virus into changing, in ways that cause it to be weaker,” he said.

“It also implies that if good ADCC antibodies were available prior to infection, via a vaccine, we might be able to stop the virus taking hold. This is the holy grail.”

The group at the University of Melbourne’s Department of Microbiology and Immunology analysed blood samples of people with HIV and found their virus had evolved to evade or ‘escape’ the ADCC antibodies against HIV they are making to try to control their virus.

The team led by Dr Ivan Stratov and Professor Kent employed a novel technology developed in their laboratory to find where ADCC antibodies were attacking the virus. They then looked at how the sequence of the virus had mutated over time to avoid the immune response.

“There is an urgent need to identify effective immunity to HIV and our studies suggest ADCC responses supply significant immune pressure on the virus,” Dr Ivan Stratov, a clinician and researcher said.

The group is now working on designing HIV vaccines to induce ADCC antibodies that make it more difficult for the virus to escape.

The work was published in the prestigious international journal PNAS.

Insight into HIV immunity may lead to vaccine
6 May 2011Latest insights into immunity to HIV could help to develop a vaccine to build antibodies’ defences against the disease, a University of Melbourne study has found.
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By investigating the action of the human antibodies called ADCC, in people with HIV, researchers were able to identify that the virus evolves to evade or ‘escape’ the antibodies.
Professor Stephen Kent of the University of Melbourne and one of the senior authors on the paper said ADCC antibodies have been strongly implicated in protection from HIV in several vaccine trials but their action was poorly understood.
“These results show what a slippery customer the HIV virus is, but also shows that these ADCC antibodies are really forcing the virus into changing, in ways that cause it to be weaker,” he said.
“It also implies that if good ADCC antibodies were available prior to infection, via a vaccine, we might be able to stop the virus taking hold. This is the holy grail.”
The group at the University of Melbourne’s Department of Microbiology and Immunology analysed blood samples of people with HIV and found their virus had evolved to evade or ‘escape’ the ADCC antibodies against HIV they are making to try to control their virus.
The team led by Dr Ivan Stratov and Professor Kent employed a novel technology developed in their laboratory to find where ADCC antibodies were attacking the virus. They then looked at how the sequence of the virus had mutated over time to avoid the immune response.
“There is an urgent need to identify effective immunity to HIV and our studies suggest ADCC responses supply significant immune pressure on the virus,” Dr Ivan Stratov, a clinician and researcher said.
The group is now working on designing HIV vaccines to induce ADCC antibodies that make it more difficult for the virus to escape.
The work was published in the prestigious international journal PNAS.

Fatal disorder gene found

Monday, 09 May 2011

Walter and Eliza Hall Institute of Medical Research

Kufs disease is a rare but fatal, hereditary neurodegenerative disease usually identified in early adulthood.

Image: annedde/iStockphoto

Scientists from the Walter and Eliza Hall Institute and the University of Melbourne have used innovative new technologies to identify the gene responsible for a rare but fatal hereditary brain disorder. The discovery will make it possible to diagnose the disease through a blood test rather than a brain biopsy.

Dr Melanie Bahlo, Ms Katherine Smith and Ms Catherine Bromhead from the Walter and Eliza Hall Institute’s Bioinformatics division, in collaboration with neurologist and epilepsy specialist Professor Sam Berkovic and Dr Todor Arsov from the University of Melbourne, have found that mutations in the CLN6 gene on chromosome 15 are the cause of inherited recessive Kufs type A disease. The paper was published in the American Journal of Human Genetics.

Kufs disease is a rare but fatal, hereditary neurodegenerative disease usually identified in early adulthood. Brain symptoms result from a build up of fat in brain cells that is toxic to the cells, causing symptoms including epilepsy, dementia, impaired motor function and intellectual deterioration. It affects approximately 1 in 1,000,000 people.

Professor Berkovic, head of the Epilepsy Research Centre at the University of Melbourne and the Comprehensive Epilepsy Program at Austin Health, said identification of the CLN6 gene would enable more efficient and much less invasive techniques for earlier diagnosis of Kufs disease.

“Currently, the only way that we can reliably diagnose this disease is to do an invasive and dangerous brain biopsy, or at autopsy,” Professor Berkovic said. “The discovery of the gene at the root of Kufs type A disease will enable us to use a rapid and simple blood test to genetically test for the disease. It will also give us the ability to screen for the disease in people in at-risk families, and make it possible for genetic counseling, which we already know to be very important for patients.”

Dr Bahlo’s and Ms Smith’s innovative work used data generated from a person’s DNA, called SNP genotyping. When combined with sophisticated mathematical and statistical analysis, the information helped them identify the region in the human genome likely to contain the DNA error that causes Kufs disease which led to discovery of the gene mutations.

“The genetic cause of Kufs disease has remained a mystery for over 25 years, because the rarity of the condition meant that our patient groups were so small we couldn’t reliably pinpoint any particular genetic mutations that caused their disease,” Dr Bahlo said. “In this study, we used an innovative suite of highly specialised techniques and statistical algorithms that compensated for the small sample size and allowed us to look at the entire genetic code of people with Kufs disease to find which region of the DNA had the mutation which caused disease. Discovering the CLN6 gene as the cause of Kufs disease is a great outcome for us and for the people who are affected by this awful disease.”

Professor Berkovic said the best possible outcome from the study would be the development of a treatment for Kufs disease, which is currently untreatable and invariably fatal. “The general aim and hope of this work is always to be able to use the discovery to translate to a treatment, but this is still some time away,” he said.

Professor Berkovic said that his team’s collaboration with Dr Bahlo’s bioinformatics group at the institute had produced several exciting results in a short time. This includes a number of important outcomes for epilepsy sufferers, with the genetic basis for four epilepsy-related diseases discovered in the past four years.

Dr Bahlo said that the innovative study used to find the gene responsible for Kufs disease could hold the key for finding the genetic cause of a number of other hereditary diseases including other epilepsy-related diseases, deafness and some familial cancers.

“These new techniques for using statistical data and mathematical algorithms to track down the genetic basis of disease are really at the forefront of medical research today,” Dr Bahlo said. “Finding the genes responsible for certain diseases will help us in our quest to generate new diagnostic tools as well as provide the basis for fundamental biology that leads to development of new drugs and therapies to treat disease.”

The work was supported by the National Health and Medical Research Council and the Batten Disease Support and Research Association.

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Thursday, May 12, 2011

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Conventional fossil fuels sometimes 'greener' than biofuels: study

Flipping hot Jupiters: Why some planets orbit the wrong way

Immature skull led young Tyrannosaurs to rely on speed, agility to catch prey

Aki Ra 2010 CNN Heroes

CNN Heroes 2011 - Everyday People Changing the World - Special Reports f...

Sneaky HIV virus found

Insight into HIV immunity may lead to vaccine

Fatal disorder gene found

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