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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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