As it is pumped through blood vessels and delivers oxygen to brain cells, blood may actually help us think.
Research done by scientists at MIT suggests that in addition to providing nutrients and oxygen to the body's cells, blood may affect the activity of neurons in the brain as it flows through, changing how they transmit signals to each other and regulating the flow of information through the brain.
"We hypothesize that blood actively modulates how neurons process information," said researcher Christopher Moore in an invited review in the Journal of Neurophysiology. "Many lines of evidence suggest that blood does something more interesting than just delivering supplies. If it does modulate how neurons relay signals, that changes how we think the brain works."
This relationship between blood flow and brain function has implications for understanding neurological diseases, such as Alzheimer's disease, schizophrenia, multiple sclerosis and epilepsy.
"Most people assume the symptoms of these diseases are a secondary consequence of damage to the neurons. But we propose that they may also be a causative factor in the disease process," Moore said.
For example, epileptics often have abnormal blood vessels in the regions of the brain where seizures occur, which suggests that abnormal blood flow could trigger the seizure.
Moore has a few theories that could explain just how blood affects neural activity, based on studies in his lab. Blood contains diffusible elements that could leak out of blood vessels and affect brain activity, and changes in blood volume could affect the concentrations of these factors. Neurons may also react to the mechanical forces applied to them when the blood vessels expand and contract.
Blood also influences the temperatures of the brain tissue, which affects the activity of the cells.
WASHINGTON – A Pentagon-chartered report urges the United States to take the lead in developing space platforms capable of capturing sunlight and beaming electrical power to Earth.
Space-based solar power, according to the report, has the potential to help the United States stave off climate change and avoid future conflicts over oil by harnessing the Sun's power to provide an essentially inexhaustible supply of clean energy.
The report, "Space-Based Solar Power as an Opportunity for Strategic Security," was undertaken by the Pentagon's National Security Space Office this spring as a collaborative effort that relied heavily on Internet discussions by more than 170 scientific, legal, and business experts around the world. The Space Frontier Foundation, an activist organization normally critical of government-led space programs, hosted the website used to collect input for the report.
Speaking at a press conference held here Oct. 10 to unveil the report, U.S. Marine Corps Lt. Col. Paul Damphousse of the National Space Security Space Office said the six-month study, while "done on the cheap," produced some very positive findings about the feasibility of space-based solar power and its potential to strengthen U.S. national security.
"One of the major findings was that space-based solar power does present strategic opportunity for us in the 21st century," Damphousse said. "It can advance our U.S. and partner security capability and freedom of action and merits significant additional study and demonstration on the part of the United States so we can help either the United State s develop this, or allow the commercial sector to step up."
Demonstrations needed
Specifically, the report calls for the U.S. government to underwrite the development of space-based solar power by funding a progressively bigger and more expensive technology demonstrations that would culminate with building a platform in geosynchronous orbit bigger than the international space station and capable of beaming 5-10 megawatts of power to a receiving station on the ground.
Nearer term, the U.S. government should fund in depth studies and some initial proof-of-concept demonstrations to show that space-based solar power is a technically and economically viable to solution to the world's growing energy needs.
Aside from its potential to defuse future energy wars and mitigate global warming, Damphousse said beaming power down from space could also enable the U.S. military to operate forward bases in far flung, hostile regions such as Iraq without relying on vulnerable convoys to truck in fossil fuels to run the electrical generators needed to keep the lights on.
As the report puts it, "beamed energy from space in quantities greater than 5 megawatts has the potential to be a disruptive game changer on the battlefield. [Space-based solar power] and its enabling wireless power transmission technology could facilitate extremely flexible 'energy on demand' for combat units and installations across and entire theater, while significantly reducing dependence on over-land fuel deliveries."
Although the U.S. military would reap tremendous benefits from space-based solar power, Damphousse said the Pentagon is unlikely to fund development and demonstration of the technology. That role, he said, would be more appropriate for NASA or the Department of Energy, both of which have studied space-based solar power in the past.
The Pentagon would, however, be a willing early adopter of the new technology, Damphousse said, and provide a potentially robust ma rk et for firms trying to build a business around space-based solar power.
"While challenges do remain and the business case does not necessarily close at this time from a financial sense, space-based solar power is closer than ever," he said. "We are the day after next from being able to actually do this."
Damphousse, however, cautioned that the private sector will not invest in space-based solar power until the United States buys down some of the risk through a technology development and demonstration effort at least on par with what the government spends on nuclear fusion research and perhaps as much as it is spending to construct and operate the international space station.
"Demonstrations are key here," he said. "If we can demonstrate this, the business case will close rapidly."
Charles Miller, one of the Space Frontier Foundation's directors, agreed public funding is vital to getting space-based solar power off the ground. Miller told reporters here that the space-based solar power industry could take off within 10 years if the White House and Congress embrace the report's recommendations by funding a robust demonstration program and provide the same kind of incentives it offers the nuclear power industry.
Military applications
The Pentagon's interest is another important factor. Military officials involved in the report calculate that the United States is paying $1 per kilowatt hour or more to supply power to its forward operating bases in Iraq .
"The biggest issue with previous studies is they were trying to get five or ten cents per kilowatt hour, so when you have a near term customer whose potentially willing to pay much more for power, its much easier to close the business case," Miller said.
NASA first studied space-based solar power in the 1970s, concluding then that the concept was technically feasible but not economically viable. Cost estimates produced at the time estimated the United States would have to spend $300 billion to $1 trillion to deliver the first kilowatt hour of space-based power to the ground, said John Mankins, a former NASA technologist who led the agency's space-based solar power research and now consults and runs the Space Power Association.
Advances in computing, robotics, solar cell efficiency, and other technologies helped drive that estimate down by the time NASA took a fresh look at space-based solar power in the mid-1990s, Mankins said, but still not enough justify the upfront expense of such an undertaking at a time when oil was going for $15 a barrel.
With oil currently trading today as high as $80 a barrel and the U.S. military paying dearly to keep kerosene-powered generators humming in an oil-rich region like Iraq, the economics have change significantly since NASA pulled the plug on space-based solar power research in around 2002.
On the technical front, solar cell efficiency has improved faster than expected. Ten years ago, when solar cells were topping out around 15 percent efficiency, experts predicted that 25 percent efficiency would not be achieved until close to 2020, Mankins said, yet Sylmar, Calif.-based Spectrolab – a Boeing subsidiary – last year unveiled an advanced solar cell with a 40.7 percent conversion efficiency.
One critical area that has not made many advances since the 1990s or even the 1970s is the cost of launch. Mankins said commercially-viable space-based solar power platforms will only become feasible with the kind of dramatically cheaper launch costs promised by fully reusable launch vehicles flying dozens of times a year.
"If somebody tries to sell you stock in a space solar power company today saying we are going to start building immediately, you should probably call your broker and not take that at face value," Mankins said. "There's a lot of challenges that need to be overcome."
Mankins said the space station could be used to host some early technology validation demonstrations, from testing appropriate materials to tapping into the station's solar-powered electrical grid to transmit a low level of energy back to Earth. Worthwhile component tests could be accomplished for "a few million" dollars, Mankins estimated, while a space station-based power-beaming experiment would cost "tens of millions" of dollars.
Placing a free-flying space-based solar power demonstrator in low-Earth orbit, he said, would cost $500 million to $1 billion. A geosynchronous system capable of transmitting a sustained 5-10 megawatts of power down to the ground would cost around $10 billion, he said, and provide enough electricity for a military base. Commercial platforms, likewise, would be very expensive to build.
"These things are not going to be small or cheap," Mankins said. "It's not like buying a jetliner. It's going to be like buying the Hoover Dam."
While the upfront costs are steep, Mankins and others said space-based solar power's potential to meet the world's future energy needs is huge.
According to the report, "a single kilometer-wide band of geosynchronous earth orbit experiences enough solar flux in one year to nearly equal the amount of energy contained within all known recoverable conventional oil reserves on Earth today."
And the Oscar Goes to… a Robot
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Image: Courtesy of Industrial Light & Magic |
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OSCAR WORTHY?: More than 30 Industrial Light & Magic (ILM) animators brought Optimus Prime and his fellow Transformers to life in last summer's special effects extravaganza. |
It is unlikely that this year's Oscar ceremony will include an award for best animated actor in a film. But that has not stopped movie companies from pushing the boundaries of animation to make their synthetic characters seem as real as possible—even if those characters happen to be shape-shifting megaton robots, as in last summer's Transformers special effects extravaganza.
The prospect of turning a lineup of toy action figures into a live-action film that kids would want to see (and their parents would want to take them to) was daunting, admits Industrial Light & Magic's (ILM) Scott Benza, the animation supervisor for Transformers. He adds, "We all scratched our heads," when we first heard about the project.
In November 2005 Transformers director Michael Bay and a team of designers provided Benza with 3-D computer images of the animated characters that Benza and more than 30 animators would eventually bring to life. These "animatics," or rough animations for the film, tell the movie's story, but they do not have any clearly defined style of movement.
"My job was to bring character to these computer animations," says Benza, who previously worked with Bay on 2005's The Island and Pearl Harbor in 2001. Indeed, animators are tasked with bringing computer-animated characters to life, particularly those with key "acting" roles. Lead animators work closely with directors to ensure they get the best performances out of their animated characters.
Even though he has more than a dozen films to his credit, including work on the 2003 film version of The Hulk that garnered him nominations for two awards from the Visual Effects Society, Benza says it was a challenge to create highly athletic performances from bulky, animated characters that appeared to be the size of small buildings and weigh several tons. "In some moments you have to sell the weight of the Transformers, in other moments you have to sell their athleticism," Benza says.
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| Image: Courtesy of Industrial Light & Magic | |
| RUSH HOUR: ILM animators were challenged to create highly athletic performances from bulky, animated characters that appeared to be the size of small buildings and weigh several tons. |
ILM animators employed a technique they refer to as "virtual background pipeline" to make sure that the animated characters had plenty of room to move in any given scene, whether they were flying, fighting or racing through an intersection. Virtual background pipeline starts by taking a large number of digital photographs of a scene or location using a tripod with a robotic head. ILM then used its custom-created Zeno software, as well as other different pieces of third-party software, to stitch the images together and re-create a seamless digital background. "These photos can also be used to create textured 3-D geometry, with a process called photomodeling—again, inside Zeno," Benza says.
Using the new seamless background combined with the textured 3-D geometry, artists at ILM, a subsidiary of Lucasfilm, Ltd., had the flexibility to alter camera moves that were filmed on location, or to create new ones. "Think of it as a projected image," Benza says. If Bay shot footage of an intersection, the animators would integrate computer imagery into Bay's background plate so they could better control the action of the animated characters moving through the scene. Virtual background pipeline was developed for The Island and was also utilized on Mission Impossible: 3, he says.
Animators also employed slow-motion photography in Transformers to control the speed and motion of some of the characters' transformations from vehicles to robots (or vice versa). "Sometimes, when the action got too fast, it was hard to tell what was happening," Benza says. "Dramatically, slow motion helped us to sell the action."
In one scene, as protagonist leader Optimus Prime (an 18-wheel Peterbilt truck that morphs into a two-story robot) slugs it out with an enemy Transformer known as Bonecrusher, animators slowed the scene as much as four times less than normal speed so that the audience could better take in the spectacle of two enormous robots crashing over a city bridge. While slow motion is typically achieved by filming scenes with a high-speed camera, Benza and his team were able to achieve the same effect by bringing the footage into Apple's Shake digital-compositing software, then retiming it using a Shake plug-in called Furnace Kronos.
One of Benza's priorities was to make the Transformers' movements as authentic as possible. Animators used Zeno rigid-body solver software written by ILM developers to film a major scene early in the movie in which an enemy Transformer called Scorponok attacks a U.S. military outpost in the desert. As its name indicates, Scorponok was designed to be a large mechanical attack scorpion. To improve the authenticity of the character's movements, animators used the software to calculate how Scorponok would move through its scenes. "We were leveraging the computer's power to help us create motion, because the computer is really good at figuring out physics," Benza says.
Benza and his team had access to sophisticated software while creating the film's action, but he says they are constantly on the lookout for new technologies to use in future movies, including a Transformers sequel. He says one way to upgrade results would be to use simulation software on par with the "finite element" applications utilized by automobile companies when running virtual crash safety tests.
These applications are complex and difficult to set up and run because they render simulated car crashes under very specific conditions, taking into account factors such as the type of vehicle, road conditions and speed. "We want to be able to leverage that technology in creating visual effects in a way that's as believable as tests done in the auto industry," Benza says. "They care a lot about getting the simulation 100 percent correct because lives are at stake." But these applications require a level of computing expertise to set up and run that is not typically found in animation departments. "We would need a simplified version," he acknowledges.
Another area where visual effects could be improved, according to Benza, is the simulation of natural phenomena such as smoke, fire and water. "I would love to see these become even more realistic," he says. "But it's very expensive and time consuming to do on our computers." This is, in part, because of the massive calculations that must be performed to, say, create an image of flowing water that looks like an actual stream. As it is, ILM used 5,500 computer processors and 220 terabytes of storage to store all the models, animation, background plates, textures, reference materials and artwork for the film. Benza is counting on the further development of computer processors that take advantage of multithreading throughput, among other technologies, to continue his quest for lifelike animation.
One microscopic organism has thrived despite remaining celibate for tens of millions of years thanks to a neat evolutionary trick, researchers said.
Asexual reproduction has allowed duplicate gene copies of the single-celled creatures -- called bdelloid rotifers -- to become different over time.
This gives the rotifers a wider pool of genes to help them adapt and survive, the researchers said in the journal Science.
"It is like having a bigger tool kit," Alan Tunnacliffe, a molecular biologist at the University of Cambridge, said in a telephone interview. "You can do the same job but better."
Other researchers had shown the translucent, waterborne creatures could survive for 40 million years without sexual relations.
The question, Tunnacliffe said, was how the creatures found in pools of water accomplished this feat without the gene-swapping made possible by sexual reproduction.
"Sexual reproduction is supposed to be a good thing in evolution," he said on Thursday.
"So when you come across an organism like the bdelloid, which hasn't engaged in sexual reproduction for tens of millions of years, you begin to question why sex is important."
Every species of plant and animal that reproduces sexually has pairs of genes nearly identical to each other, with one of each pair coming from the mother and father.
These creatures get around that problem with the evolutionary trick that allows their genes to drift apart and evolve on their own, Tunnacliffe said, after using molecular cloning techniques.
"No sex means the genes can evolve in different directions," he said. "It is like you have a bigger gene pool to select from for different functions in evolution."
The theory of natural selection says sex mixes up the genes to cope with unexpected changes in a treacherous world.
Some genetic changes are good and boost survival, for example against new strains of disease, but others lead to conditions like cystic fibrosis in humans.
Making Plastic as Strong as Steel
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Image: Courtesy of the University of Michigan |
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NEW STEEL: University of Michigan researchers have found a way to make a composite plastic that's as strong steel but lighter, transparent and thin as a piece of plastic wrap. |
Could a seemingly simple clear plastic bag—the kind that you load your fruits and vegetables into at the supermarket—actually be as strong as steel? It could if it was made from a new composite plastic that blends the strength of nanoparticles with the pliancy of a water-soluble polymer.
Although it is no secret that nanotubes, nanosheets and nanorods are incredibly strong when combined in small numbers, larger materials made out of these microscopic building blocks cannot utilize much of that strength because the links between them are weak. But University of Michigan at Ann Arbor researchers report in Science that they have found a way to scale the strength of the nanomaterials to larger materials by transferring stress between nanosheets and a nanoscale polymer resembling white glue. Visually, it looks like a brick wall, where clay nanosheet "bricks" are held together by water-soluble polyvinyl alcohol "mortar." The result, according to the researchers, is a composite plastic that is light and transparent but as strong steel.
"If you take the nanoscale materials individually, say one carbon tube or one clay sheet, their mechanical properties will be astonishing," says U.M. engineering professor Nicholas Kotov, a co-author of the study. Simply combining a large volume of clay, nanosize platelets into one continuous block, however, results in a brittle chalklike material riddled with cracks.
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| Image: Courtesy of the University of Michigan | |
| A CLOSER LOOK: The composite looks like a brick wall, where clay nanosheet "bricks" are held together by water-soluble polyvinyl alcohol "mortar." |
The bricks-and-mortar structure allowed the layers to form cooperative hydrogen bonds, which gives rise to what Kotov called "the Velcro effect"—one of the reasons the material is so strong. Such bonds, if broken, can reform easily in a new place. Kotov is developing methods to apply the composite in the development of microelectromechanical systems (MEMS) and devices, as well as microfluidics devices for actuation and valve manufacturing. In addition to military uses, improving the ductility of the researchers' nanoinfused plastics could aid in the development of dent and scratch-resistant cars and windshields.
Now that the researchers have created a composite exhibiting resistance to deformation (stiffness) and resistance to load (strength), they are working to improve the composite's ability to dissipate energy, thus improving its toughness, says U.M. mechanical engineering professor Ellen Arruda, another of the study's co-authors. "We want the material to have the ability to absorb the energy of a projectile," she says.
The impetus for the research was a $1.2-million grant awarded last year by the U.S. Defense Department, which was interested in developing more effective armor for the Air Force's unmanned aerial craft as well as for vehicles and body armor for other branches of the armed forces.
The cost of this composite is difficult to estimate, Kotov says. The components are inexpensive and the process does not require large energy expenditures, but it is by no means a fast process. Cost will depend largely on how efficiently processes are developed to create nanoinfused composites and whether these composites need to be produced in high volumes. For highly specialized technologies such as MEMS and microfluidics devices, cost would not be as great an issue as it would in creating large sheets of armor.
The development of these composites is also expected to take less of a toll on the environment, because this superstrong polymer does not require the high temperatures or great energy expenditures required to make steel.
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