Program 632,
  June 6, 2000


A. New Materials have "Reversed" Physical Properties

Narrator: This is Science Today. Physicists at the University of California, San Diego have developed a new class of materials that's been theorized but never before seen in nature. Project scientist David Smith says these unique materials essentially reverse many of the physical electromagnetic or light scattering properties governing normal materials, including the Doppler effect.

Smith:The analogy with sound for example, if you see a fire engine coming toward you and it has a siren on, you hear it shifted up in frequency and when it passes, it goes down in frequency. Well, the same thing happens with light. In this "left handed" medium, the opposite occurs.

Narrator: "Left-handed" refers the new materials' ability to reverse one of the "right-hand" rules of physics, such as the direction of electric and magnetic waves. By controlling this direction, there's the potential for new devices.

Smith: The obvious example is the communications industry which is filled with applications and needs of controlling all forms of radiation from microwave down to megahertz radio waves and even up to infrared and light waves.

Narrator: For Science Today, I'm Larissa Branin.

B. New Insight into Watershed Systems

Narrator: This is Science Today. A mathematical technique similar to one used in astrophysics has helped researchers measure how long watersheds hold water and over what time scales they released that water into streams. James Kirchner, a professor of geology and geophysics at the University of California, Berkeley, was one of the study's lead authors.

Kirchner: In general, watersheds flush themselves out over much longer time scales and having much longer chemical memory of the rain that has fallen on them or the fertilizers that have been spread on them or what have you, than anyone previously expected.

Narrator: Basically, contaminants will initially be flushed out quickly, but then low-level contamination will be fed to streams for a surprisingly long time. Kirchner recently used a similar mathematical technique to measure the time lag of the Earth's recovery after an extinction event.

Kirchner: The actual sort of mathematics is all done fairly simply on a personal computer. So, intellectually it's rocket science, but these days it's very simple to do the calculations.

Narrator: For Science Today, I'm Larissa Branin.

C. The Many Sources of an Ozone-depleting Substance

Narrator: This is Science Today. Methyl bromide is a substance that's produced naturally by the oceans and plants on land. But it's also a widely manufactured pesticide and by-product of fuel combustion. Robert Rhew, a researcher at the University of California's Scripps Institution of Oceanography, says because methyl bromide is an ozone-depleting substance, there are national efforts to control its production.

Rhew: And the big question is - how much is being produced by humans and how much is being produced by nature? And what I'm working on is trying to figure out how the natural system works independent of the human system. In order to try to understand what's happening currently in the atmosphere, that's a prerequisite to trying to predict what's going to happen in the future - especially when we want to implement certain regulations.

Narrator: Rhew and his colleagues recently discovered salt marshes are one of the largest land sources of methyl bromide - but there's still about 30% that's unaccounted for.

Rhew: By identifying this new terrestrial source for these compounds, we're adding a piece to the puzzle.

Narrator: For Science Today, I'm Larissa Branin.

D. An Association between Back Injury and Job Stress

Narrator: This is Science Today. Job stress has been linked to a higher incidence of back injury. Dr. Niklas Krause, an epidemiologist at the University of California, Berkeley says before, job stress was considered a characteristic of someone's personality - not a cause of injury. With both physical workload and job stress in mind, Krause studied the rate of back injury in bus drivers.

Krause: It's known that they have a very stressful job - you know, they're not just driving a big vehicle but have hundreds of people and safety issues in their mind and have to deal with customers. And we saw that the more problems they had - crime or accidents or fare evasion or trouble with a supervisor - the more injuries they've had.

Narrator: These findings are significant since it proves for the first time factors other than physical workload can be predictors of injury.

Krause: : It's another piece of evidence that will lead to the acceptance as job stress as a risk factor for low back pain at the workplace. So you can not blame the individual of not dealing right with the stress in this case anymore. It doesn't make sense.

Narrator: For Science Today, I'm Larissa Branin.

E. Stomping on Cigar Chomping

Narrator: This is Science Today. Just what's behind the popular trend of cigar smoking? Health policy researcher Lisa Bero of the University of California, San Francisco is trying to find out. Since the early Nineties, cigar sales have risen 50 percent. At first, Bero thought this was a reaction against what she calls the "health police."

Bero: I thought that was kind of an interesting idea. People are maybe fed up with this idea that they just have to be healthy all the time. But what was interesting is in our sample so far, that hasn't come up as a big reason for why people are smoking cigars. It hasn't been the reaction to the health police. What it has been is this whole power and glamour and success story. That's been the big theme that's coming across.

Narrator: Bero and her colleagues have been studying the portrayal of cigars in the media, particularly print. They've found the coverage has been pushing the glamour factor without noting the health risks.

Bero: If you read these articles that are glamorizing cigars - think about what's bad about cigars. And think you're being led down the same road that you were led down with cigarettes.

Narrator: For Science Today, I'm Larissa Branin.



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