Sunday, July 20, 2008

Hydrogen Vehicles Coming Soon? Two Million Could Be On Roads By 2020


Rear view of a hydrogen fuel cell car. By 2023, the total cost of fuel cell vehicles, including the cost of hydrogen fuel over a vehicle's lifetime, could become competitive with conventional vehicles.

A transition to hydrogen vehicles could greatly reduce U.S. oil dependence and carbon dioxide emissions, says a new congressionally mandated report from the National Research Council, but making hydrogen vehicles competitive in the automotive market will not be easy. While the development of fuel cell and hydrogen production technology over the past several years has been impressive, challenges remain.

Vehicle costs are high, and the U.S. currently lacks the infrastructure to produce and widely distribute hydrogen to consumers. These obstacles could be overcome, however, with continued support for research and development and firm commitments from the automotive industry and the federal government, concluded the committee that wrote the report.

Light-duty vehicles, such as cars, SUVs, and pickup trucks, are responsible for 44 percent of the oil used in the United States and over 20 percent of the carbon dioxide emitted. Concerns over climate change, oil imports, and recent spikes in gasoline prices have spurred interest in the development of alternative fuels. In 2003, President Bush announced a $1.2 billion initiative to encourage development of hydrogen production technology and fuel cell vehicles, which are powered through a chemical reaction between hydrogen and oxygen and emit only water and heat as exhaust.

The committee estimated the maximum number of hydrogen vehicles that could be on the road in the coming decades, assuming that practical technical goals are met, that consumers want hydrogen cars, and that government policies are in place to help drive the transition from oil to hydrogen fuel. The findings therefore represent potential best-case scenarios rather than predictions.

According to the committee, it will take many years before hydrogen vehicles will significantly penetrate the light-duty fleet, even though technological developments have been progressing rapidly. Production of hydrogen vehicles could increase significantly by 2015. At this stage, their cost -- although dropping rapidly -- would still need to be heavily subsidized for consumers.

The maximum practicable number of hydrogen vehicles that could be on the road by 2020 is 2 million, says the report. By 2023, the total cost of fuel cell vehicles, including the cost of hydrogen fuel over a vehicle's lifetime, could become competitive with conventional vehicles. At that point, the number of hydrogen vehicles on the road could grow rapidly, to nearly 60 million in 2035 and 200 million by 2050.

The committee also calculated the investments, both public and private, that would be needed to make a complete transition from oil to hydrogen fuel. These costs include research and development, vehicle deployment, and establishing infrastructure. According to the committee, government support via strong policy initiatives as well as funding would be needed until at least 2023. The cost to the government would be about $55 billion between 2008 and 2023; private industry would be expected to invest $145 billion over that same time period. To put these numbers into perspective, the government subsidy for ethanol fuel could grow to $15 billion per year by 2020.

The shift toward hydrogen fuel would not have a large impact on oil usage or greenhouse gas emissions until hydrogen vehicles make up a significant portion of the market. If hydrogen vehicles eventually took over the market, there would be great decreases in both, although the overall effect on greenhouse gas emissions would depend upon how the hydrogen fuel was produced. The committee compared these reductions with those that might be achieved by either improving the fuel efficiency of conventional vehicles or by converting to biofuels. Because they can be implemented more rapidly, both of these options could produce reductions in oil use and emissions faster than hydrogen, but after about 2040, hydrogen would become more effective.

The greatest possible reductions would occur if biofuels, fuel-efficient conventional vehicles, and hydrogen vehicles are all pursued simultaneously, rather than seen as competitors. This "portfolio approach," if accompanied by government policies driving a transition toward reduced oil use and low-carbon fuels, could reduce greenhouse gas emissions from cars and trucks to less than 20 percent of current levels and could nearly eliminate oil demand for these vehicles by 2050, the committee said.

The study was sponsored by the U.S. Department of Energy. The National Academy of Sciences, National Academy of Engineering, Institute of Medicine, and National Research Council are private, nonprofit institutions that provide science, technology, and health policy advice under a congressional charter. The National Research Council is the principal operating agency of the National Academy of Sciences and the National Academy of Engineering.

Nature-Nurture Gene Link Sheds New Light On Autism


Researchers believe autism spectrum disorders are tied to brain changes that occur during critical periods of development.

Neuroscientists at MIT's Picower Institute for Learning and Memory found that a previously unsuspected set of genes links nature and nurture during a crucial period of brain development.

The results, reported in the July 8 issue of the Proceedings of the National Academy of Sciences (PNAS), could lead to treatments for autism and other disorders thought to be tied to brain changes that occur when the developing brain is very susceptible to inputs from the outside world. Nature--in the form of genes--and nurture--in the form of environmental influences--are fundamentally intertwined during this period.

"Our work points to how a disorder can be genetic and yet be dependent on the environment," said co-author Mriganka Sur, Sherman Fairchild Professor of Neuroscience at the Picower Institute and chair of MIT's brain and cognitive sciences department. "Many genes require activity to be expressed and make their assigned proteins. They alter their expression when activity is altered. Thus, we reveal an important mechanism of brain development that should open up a window into the mechanisms and treatment of brain disorders such as autism."

In the brain, some genes are only expressed, or turned on, in response to stimulus from the outside world. Like a panel of switches that turn lights on and off, genes that don't receive electricity don't "turn on" and express their particular proteins.

Sur and colleagues found a set of novel genes--including a calcium sensor called cardiac Troponin C, or cTropC--particularly sensitive to a critical period of development. The lack of proteins from these genes during a key phase of development could be one of the culprits in developing autism.

Researchers have long investigated the molecular mechanisms involved in monocular deprivation--when one eye is deprived of sight during a critical period of brain development, that eye becomes permanently blind, even after it is uncovered. This phenomenon is considered an important model for brain development because synapses for the covered eye--deprived of environmental stimulus, or what Sur calls "nurture"--shrivel up or get reassigned to other uses.

Sur and his colleagues looked at which genes are expressed, and which are not, when this phenomenon occurs. They hoped to pin down the correlation between nature--meaning the genes--and the external environment, or nurture. By identifying which genes are particularly apt to switch their expression patterns in response to "nurture," the researchers potentially narrowed down the ones that may be implicated in developmental disorders.

Researchers believe autism spectrum disorders are tied to brain changes that occur during critical periods of development. Different but overlapping critical periods are thought to exist for various cognitive functions affected in autism, such as language and social behaviors.

"Autism is a strongly genetic disorder: genes set up risk factors but by themselves simply make proteins," Sur said. "Genes work together with other influences. In the case of autism, these influences are unknown but could be molecules made by other genes or chemicals from the environment."

If scientists understood how genes changed in response to environmental influences during this crucial developmental period, they might be able to one day prevent or reverse the changes.

In addition to Sur, authors are Alvin W. Lyckman, a former MIT postdoctoral associate now at Tufts University; MIT brain and cognitive sciences graduate students Sam H. Horng and Cortina L. McCurry; Picower Institute postdoctoral fellows Daniela Tropea and Audra Van Wart and colleagues from other institutions.

Friday, June 13, 2008

Freshwater Runoff From Greenland Ice Sheet Will More Than Double By End Of Century

The Greenland Ice Sheet is melting faster than previously calculated according to a scientific paper by University of Alaska Fairbanks researcher Sebastian H. Mernild published recently in the journal Hydrological Processes.

The study is based on the results of state-of-the-art modeling using data from the Intergovernmental Panel on Climate Change as well as satellite images and observations from on the ground in Greenland.

Mernild and his team found that the total amount of Greenland Ice Sheet freshwater input into the North Atlantic Ocean expected from 2071 to 2100 will be more than double what is currently observed. The current East Greenland Ice Sheet freshwater flux is 257 km3 per year from both runoff and iceberg calving. This freshwater flux is estimated to reach 456 km3 by 2100.

Mernild’s results further show a change in total East Greenland freshwater flux from today’s values of 438 km3 per year to 650 km3 per year by 2100. This indicates an increase in global sea level rise estimates from 1.1 millimeters per year to 1.6 millimeters per year.

“The Greenland Ice Sheet mass balance is changing as a response to the altered climatic state,” said Mernild. “This is faster than expected. This affects freshwater runoff input to the North Atlantic Ocean, and plays an important role in determining the global sea level rise and global ocean thermohaline circulation.”

Mernild is conducting the research as part of the University of Alaska’s International Polar Year efforts. He was appointed a University of Alaska IPY postdoctoral fellow by UA president Mark Hamilton in 2007.





























Southern tip of Greenland on November 2, 2001. New data shows that the Greenland Ice Sheet is melting faster than previously calculated.

Life's Raw Materials May Have Come From The Stars, Scientists Confirm

Scientists have confirmed for the first time that an important component of early genetic material which has been found in meteorite fragments is extraterrestrial in origin, in a paper published on 15 June 2008.

The finding suggests that parts of the raw materials to make the first molecules of DNA and RNA may have come from the stars.

The scientists, from Europe and the USA, say that their research provides evidence that life’s raw materials came from sources beyond the Earth.

The materials they have found include the molecules uracil and xanthine, which are precursors to the molecules that make up DNA and RNA, and are known as nucleobases.

The team discovered the molecules in rock fragments of the Murchison meteorite, which crashed in Australia in 1969.

They tested the meteorite material to determine whether the molecules came from the solar system or were a result of contamination when the meteorite landed on Earth.

The analysis shows that the nucleobases contain a heavy form of carbon which could only have been formed in space. Materials formed on Earth consist of a lighter variety of carbon.

Lead author Dr Zita Martins, of the Department of Earth Science and Engineering at Imperial College London, says that the research may provide another piece of evidence explaining the evolution of early life. She says:

“We believe early life may have adopted nucleobases from meteoritic fragments for use in genetic coding which enabled them to pass on their successful features to subsequent generations.”

Between 3.8 to 4.5 billion years ago large numbers of rocks similar to the Murchison meteorite rained down on Earth at the time when primitive life was forming. The heavy bombardment would have dropped large amounts of meteorite material to the surface on planets like Earth and Mars.

Co-author Professor Mark Sephton, also of Imperial’s Department of Earth Science and Engineering, believes this research is an important step in understanding how early life might have evolved. He added:

“Because meteorites represent left over materials from the formation of the solar system, the key components for life -- including nucleobases -- could be widespread in the cosmos. As more and more of life’s raw materials are discovered in objects from space, the possibility of life springing forth wherever the right chemistry is present becomes more likely.”



Stardust from Murchison-meteorite. New finding suggests that parts of the raw materials to make the first molecules of DNA and RNA may have come from the stars.

Friday, April 25, 2008

Exotic Quantum State Of Matter Discovered


A team of scientists from Princeton University has found that one of the most intriguing phenomena in condensed-matter physics -- known as the quantum Hall effect -- can occur in nature in a way that no one has ever before seen.

Writing in the April 24 issue of Nature, the scientists report that they have recorded this exotic behavior of electrons in a bulk crystal of bismuth-antimony without any external magnetic field being present. The work, while significant in a fundamental way, could also lead to advances in new kinds of fast quantum or "spintronic" computing devices, of potential use in future electronic technologies, the authors said.

"We had the right tool and the right set of ideas," said Zahid Hasan, an assistant professor of physics who led the research and propelled X-ray photons at the surface of the crystal to find the effect. The team used a high-energy, accelerator-based technique called "synchrotron photo-electron spectroscopy."

And, Hasan added, "We had the right material."

The quantum Hall effect has only been seen previously in atomically thin layers of semiconductors in the presence of a very high applied magnetic field. In exploring new realms and subjecting materials to extreme conditions, the scientists are seeking to enrich the basis for understanding how electrons move.

Robert Cava, the Russell Wellman Moore Professor of Chemistry and a co-author on the paper, worked with members of his team to produce the crystal in his lab over many months of trial-and-error. "This is one of those wonderful examples in science of an intense, extended collaboration between scientists in different fields," said Cava, also chair of the Department of Chemistry.

"This remarkable experiment is a major home run for the Princeton team," said Phuan Ong, a Princeton professor of physics who was not involved in the research. Ong, who also serves as assistant director of the Princeton Center for Complex Materials, added that the experiment "will spark a worldwide scramble to understand the new states and a major program to manipulate them for new electronic applications."

Electrons, which are electrically charged particles, behave in a magnetic field, as some scientists have put it, like a cloud of mosquitoes in a crosswind. In a material that conducts electricity, like copper, the magnetic "wind" pushes the electrons to the edges. An electrical voltage rises in the direction of this wind -- at right angles to the direction of the current flow. Edwin Hall discovered this unexpected phenomenon, which came to be known as the Hall effect, in 1879. The Hall effect has become a standard tool for assessing charge in electrical materials in physics labs worldwide.

In 1980, the German physicist Klaus von Klitzing studied the Hall effect with new tools. He enclosed the electrons in an atom-thin layer, and cooled them to near absolute zero in very powerful magnetic fields. With the electrons forced to move in a plane, the Hall effect, he found, changed in discrete steps, meaning that the voltage increased in chunks, rather than increasing bit by bit as it was expected to. Electrons, he found, act unpredictably when grouped together. His work won him the Nobel Prize in physics in 1985.

Daniel Tsui (now at Princeton) and Horst Stormer of Bell Laboratories did similar experiments, shortly after von Klitzing's. They used extremely pure semiconductor layers cooled to near absolute zero and subjected the material to the world's strongest magnet. In 1982, they suddenly saw something new. The electrons in the atom-thin layer seemed to "cooperate" and work together to form what scientists call a "quantum fluid," an extremely rare situation where electrons act identically, in lock-step, more like soup than as individually spinning units.

After a year of thinking, Robert Laughlin, now at Stanford University, devised a model that resembled a storm at sea in which the force of the magnetic wind and the electrons of this "quantum fluid" created new phenomena -- eddies and waves -- without being changed themselves. Simply put, he showed that the electrons in a powerful magnetic field condensed to form this quantum fluid related to the quantum fluids that occur in superconductivity and in liquid helium.

For their efforts, Tsui, Stormer and Laughlin won the Nobel Prize in physics in 1998.

Recently, theorist Charles Kane and his team at the University of Pennsylvania, building upon a model proposed by Duncan Haldane of Princeton, predicted that electrons should be able to form a Hall-like quantum fluid even in the absence of an externally applied magnetic field, in special materials where certain conditions of the electron orbit and the spinning direction are met. The electrons in these special materials are expected to generate their own internal magnetic field when they are traveling near the speed of light and are subject to the laws of relativity.

In search of that exotic electron behavior, Hasan's team decided to go beyond the conventional tools for measuring quantum Hall effects. They took the bulk three-dimensional crystal of bismuth-antimony, zapped it with ultra-fast X-ray photons and watched as the electrons jumped out. By fine-tuning the X-rays, they could directly take pictures of the dancing patterns of the electrons on the edges of the sample. The nature of the quantum Hall behavior in the bulk of the material was then identified by analyzing the unique dancing patterns observed on the surface of the material in their experiments.

Kane, the Penn theorist, views the Princeton work as extremely significant. "This experiment opens the door to a wide range of further studies," he said.

The images observed by the Princeton group provide the first direct evidence for quantum Hall-like behavior without external magnetic fields.

"What is exciting about this new method of looking at the quantum Hall-like behavior is that one can directly image the electrons on the edges of the sample, which was never done before," said Hasan. "This very direct look opens up a wide range of future possibilities for fundamental research opportunities into the quantum Hall behavior of matter."

Other researchers on the paper include graduate students David Hsieh, Andrew Lewis Wray, YuQi Xia and postdoctoral fellows Dong Qian and Yew San Hor. The team members are in the departments of physics and chemistry, and are members of the Princeton Center for Complex Materials. They used facilities at the Lawrence Berkeley Laboratory in Berkeley, Calif., and the University of Wisconsin's Synchrotron Radiation Center in Stoughton, Wis.

This work was supported by U.S. Department of Energy and the National Science Foundation.

Wednesday, March 5, 2008

First Humanoid Robot That Will Develop Language May Be Coming Soon


Cub, a one meter-high baby robot which will be used to study how a robot could quickly pick up language skills, will be available next year.
iCub, a one metre-high baby robot which will be used to study how a robot could quickly pick up language skills, will be available next year.

Professor Chrystopher Nehaniv and Professor Kerstin Dautenhahn at the University of Hertfordshire’s School of Computer Science are working with an international consortium led by the University of Plymouth on ITALK (Integration and Transfer of Action and Language Knowledge in Robots), which begins on 1 March.

ITALK aims to teach the robot to speak by employing the same methods used by parents to teach their children. Professor Nehaniv and Professor Dautenhahn, who are European leaders in Artificial Intelligence and Human Robot Interaction, will conduct experiments in human and robot language interaction to enable the robot to converse with humans.

Typical experiments with the iCub robot will include activities such as inserting objects of various shapes into the corresponding holes in a box, serialising nested cups and stacking wooden blocks. Next, the iCub will be asked to name objects and actions so that it acquires basic phrases such as "robot puts stick on cube".

Professor Nehaniv said: “Our approach is that robot will use what it learns individually and socially from others to bootstrap the acquisition of language, and will use its language abilities in turn to drive its learning of social and manipulative abilities. This creates a positive feedback cycle between using language and developing other cognitive abilities. Like a child learning by imitation of its parents and interacting with the environment around it, the robot will master basic principles of structured grammar, like negation, by using these abilities in context.”

The scientific and technological research developed during the project will have a significant impact on the future generation of interactive robotic systems within the next ten years and the leadership role of Europe in this area.

Speaking about the research, Professor Dautenhahn said: “iCub will take us a stage forward in developing robots as social companions. We have studied issues such as how robots should look and how close people will want them to approach and now, within a year, we will have the first humanoid robot capable to developing language skills.”

Boys And Girls Brains Are Different: Gender Differences In Language Appear Biological


New research shows that areas of the brain associated with language work harder in girls than in boys during language tasks, and that boys and girls rely on different parts of the brain when performing these tasks.
Although researchers have long agreed that girls have superior language abilities than boys, until now no one has clearly provided a biological basis that may account for their differences.

For the first time -- and in unambiguous findings -- researchers from Northwestern University and the University of Haifa show both that areas of the brain associated with language work harder in girls than in boys during language tasks, and that boys and girls rely on different parts of the brain when performing these tasks.

"Our findings -- which suggest that language processing is more sensory in boys and more abstract in girls -- could have major implications for teaching children and even provide support for advocates of single sex classrooms," said Douglas D. Burman, research associate in Northwestern's Roxelyn and Richard Pepper Department of Communication Sciences and Disorders.

Using functional magnetic resonance imaging (fMRI), the researchers measured brain activity in 31 boys and in 31 girls aged 9 to 15 as they performed spelling and writing language tasks.

The tasks were delivered in two sensory modalities -- visual and auditory. When visually presented, the children read certain words without hearing them. Presented in an auditory mode, they heard words aloud but did not see them.

Using a complex statistical model, the researchers accounted for differences associated with age, gender, type of linguistic judgment, performance accuracy and the method -- written or spoken -- in which words were presented.

The researchers found that girls still showed significantly greater activation in language areas of the brain than boys. The information in the tasks got through to girls' language areas of the brain -- areas associated with abstract thinking through language. And their performance accuracy correlated with the degree of activation in some of these language areas.

To their astonishment, however, this was not at all the case for boys. In boys, accurate performance depended -- when reading words -- on how hard visual areas of the brain worked. In hearing words, boys' performance depended on how hard auditory areas of the brain worked.

If that pattern extends to language processing that occurs in the classroom, it could inform teaching and testing methods.

Given boys' sensory approach, boys might be more effectively evaluated on knowledge gained from lectures via oral tests and on knowledge gained by reading via written tests. For girls, whose language processing appears more abstract in approach, these different testing methods would appear unnecessary.

"One possibility is that boys have some kind of bottleneck in their sensory processes that can hold up visual or auditory information and keep it from being fed into the language areas of the brain," Burman said. This could result simply from girls developing faster than boys, in which case the differences between the sexes might disappear by adulthood.

Or, an alternative explanation is that boys create visual and auditory associations such that meanings associated with a word are brought to mind simply from seeing or hearing the word.

While the second explanation puts males at a disadvantage in more abstract language function, those kinds of sensory associations may have provided an evolutionary advantage for primitive men whose survival required them to quickly recognize danger-associated sights and sounds.

If the pattern of females relying on an abstract language network and of males relying on sensory areas of the brain extends into adulthood -- a still unresolved question -- it could explain why women often provide more context and abstract representation than men.

Ask a woman for directions and you may hear something like: "Turn left on Main Street, go one block past the drug store, and then turn right, where there's a flower shop on one corner and a cafe across the street."

Such information-laden directions may be helpful for women because all information is relevant to the abstract concept of where to turn; however, men may require only one cue and be distracted by additional information.