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SCIENCE

Because the steel is nonmagnetic, it offers new stealth possibilities for ships, ordinarily detectable by their magnetic fields, and the ability for a ship to ignore magnetically detonated mines. The research, reported in the latest issue of the Journal of Materials Research, was carried out under a grant from the Defense Department's Defense Advanced Research Projects Agency.

The problem now, explained Shiflet, is that the new steel is brittle, with a tendency to shatter: "We'd like to have some ability to bend it at room temperature," he said in a telephone interview.

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One way is to add other elements "to weaken the bonds and get more 'give,' " Shiflet said. "You sacrifice some strength, but get the flexibility." He and Poon are also reheating the steel until it starts to recrystallize at 1,100 degrees Fahrenheit: "You try to control the process so you still have an amorphous matrix with crystals embedded."

-- Guy Gugliotta

Blocked Brain Circuit Turns Monkeys Into Workaholics

Monkeys worked harder for rewards when scientists temporarily blocked a brain circuit that told the animals how close the reward was, according to a paper to be published this week in the Proceedings of the National Academy of Sciences.

The technique was effectively a fix for one form of procrastination, scientists concluded. No one is considering treating humans or animals for being lazy, but the new research elegantly showed how the brain's reward circuitry works and may shed light on certain mental illnesses.

"The monkeys became extreme workaholics," said Barry J. Richmond, one of the authors and a researcher at the National Institute of Mental Health, in a description of the work issued by the federal institution.

Where the monkeys had slacked off on a computer test when they knew a tasty reward was a long time away, they worked harder when scientists temporarily blocked a reward circuit in the brain involving the neurotransmitter dopamine.

"Like people, they tend to procrastinate when they know they will have to do more work before getting a reward," Richmond said.

Once the animals lost the sense that a tasty reward was far away or near, they applied themselves to the computer test as if the reward was near. Scientists believe the work can help shed light on why some people with certain mental illnesses are unmotivated to work, while other illnesses cause people to apply themselves obsessively to certain tasks.

-- Shankar Vedantam


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