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Cells in the central nervous system communicate with each other through electrical signals that travel from neuron to neuron. But how does the brain translate this information to allow us to perceive the world?
It has been widely believed that these signals generate "spiked patterns" that encode different types of cognitive information. According to the theory, the brain is able to discriminate between, say, a door and a table because each generates a distinct sequence of patterns. Upon repeated presentation of that object, its pattern is reproduced in a controlled manner. Previous experiments had demonstrated repeating patterns lasting up to one second.
But when Weizmann Institute neurobiologist Dr. Ilan Lampl and colleagues recorded the activity of neurons in the cortex of anesthetized rats and analyzed the data, they found no difference in the number of patterns produced or the time it takes for various patterns to repeat themselves, compared with data that was randomized. They therefore concluded that the patterns observed could not be due to the deterministically controlled mechanisms posited in the theory, but occur purely by chance.
This research is likely to contribute significantly to the ongoing debate on neuronal coding.
Says Lampl: "Since the 1980s, neuroscientists believed they possessed the key for beginning to understand the workings of the brain. But we have provided strong evidence to suggest that the brain may not encode information using precise patterns of activity."
His findings were published recently in the journal Neuron.
SCIENCE IN THREE MINUTES
The British Council-Israel, which closed its library in Jerusalem recently, has found new ways to invest its energies. It is launching a new initiative to encourage young scientists to communicate with the public. Based on the UK model of FameLab, the British Council - together with the Science Festival at the Weizmann Institute ), the Bloomfield Science Museum in Jerusalem and the Hemda Science Education Center Tel Aviv - ran science communication competitions to discover the new voices of Israeli science. In Israel, FameLab is supported by Teva Pharmaceutical and the Scientific American-Israel journal.
"We're looking for people who have scientific stars in their eyes, people who can present an entertaining, original and exciting talk in a few minutes that is scientifically accurate but appealing to a non-scientific audience," explains Kathy Sykes, Cheltenham Science Festival Director in the UK.
FameLab encourages scientists to excite public imagination with a vision of science in the 21st century. At the competitions in March and early April, contestants had just three minutes to prove to a panel of judges they've got what it takes to make science come alive. The competitions were in Hebrew. Nine finalists were given the opportunity to participate in a master class before going on to compete in the final on May 2 at the Hemda Center. The Israeli winner of FameLab 2007 will enjoy a fully paid visit to the Cheltenham Science Festival in June. For further information, contact Sonia Feldman at the British Council (03) 611-3626 or e-mail firstname.lastname@example.org.
"Juicing up" your cellphone or iPod may take on a whole new meaning in the future. Researchers at Saint Louis University in Missouri have developed a battery that runs on virtually any sugar source, from soft drinks to tree sap, and can operate three to four times longer on a single charge than conventional lithium ion batteries.
The new battery, which is also biodegradable, could replace lithium ion batteries in many portable applications, including computers, the scientists say. Their findings were described at the recent 233rd national meeting of the American Chemical Society.
"This study shows that renewable fuels can be directly employed in batteries at room temperature to lead to more energy efficient technology," says study leader Dr. Shelley Minteer, an electrochemist at Saint Louis University. "It demonstrates that by bridging biology and chemistry, we can build a better battery that's also cleaner for the environment."
Using sugar for fuel is not a new concept; sugar in the form of glucose supplies the energy needs of all living things. While Nature long ago figured out how to harness this energy efficiently, scientists have only recently learned the secret, Minteer says.
A few other researchers also have developed batteries that run on sugar, but Minteer claims her version is the longest-lasting and most powerful. As proof of concept, she has used a small prototype (about the size of a postage stamp) to run a handheld calculator. If the battery continues to show promise, it could be ready for commercialization in three to five years, she estimates.
Consumers aren't the only ones who stand to benefit from this technology. The military is interested in using "the sugar battery" to power electronic equipment on the battlefield and in emergency situations. These devices include sensors for detecting biological and chemical weapons. Devices could be instantly recharged by adding virtually any convenient sugar source, including sap, Minteer says. Like other fuel cells, the sugar battery contains enzymes that convert fuel - in this case, sugar - into electricity, leaving water as a main byproduct. But unlike other fuel cells, all the materials used to build the sugar battery are biodegradable.
So far, Minteer has run the batteries on glucose, flat soda, sweetened drink mix and tree sap, with promising results. She also tested carbonated beverages, but carbonation appears to weaken the cell. She says the best fuel source tested so far is ordinary table sugar dissolved in water.
One of the first applications Minteer envisions for the sugar fuel cell is as a portable cellphone recharger, similar to the quick rechargers already on the market that allow users to charge their phones while on the go. Ideally, these rechargers would contain cartridges pre-filled with a sugar solution that can be replaced when they're used up.