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A.
An Aircraft Wing Design That Dramatically Reduces
Wake Turbulence
Narrator:
This is Science Today. The strength of the turbulence
generated in a plane's wake can be significantly
reduced by the addition of triangular flaps on the
aircraft's wings. Mechanical engineer Omer Savas,
of the University of California, Berkeley, says
the triangular flaps work by destabilizing wake
turbulence, or wake vortices.
Savas:
We designed a simple wing basically taking an ordinary
wing and putting outboard flaps, as opposed to inboard
flaps. By doing that we were able to generate this
vortice system, which causes internal instabilites
within the vortice system and destabilizes the whole
wake and makes it less harmful to the airplane which
is following it.
Narrator:
Savas says their wing design could make a substantial
difference not only in flight safety, but also airport
capacity.
Savas:
The reason why you wait at the beginning of the
runway for a minute and a half or so is that you
have to wait for the vortice system to dissipate
itself. 6:50 So the question was, what can we do
to shorten this time? Quite a few of the airports
across the world - the capacity has been limited
by this vortice behavior.
Narrator:
For Science Today, I'm Larissa Branin.
B.
Excessive TV Viewing of the 9/11 Attacks May Trigger
Stress Disorder
Narrator:
This is Science Today. A national, randomized survey
taken shortly after the terrorist attacks on September
11th revealed that almost half of those polled experienced
extreme stress over the event - even though they had
no direct relationship to the victims or the sites
involved. Dr. Frank Schoenfeld, a clinical psychiatrist
at the University of California, San Francisco, says
this study also suggested that some people might be
at risk of developing post traumatic stress disorder
from excessive viewing of the attacks on television.
Schoenfeld: Judging from some
of the earlier studies, there will be some people
that will have been affected to the point where they
might require medical attention just on the basis
of this viewing.
Narrator: Schoenfeld says symptoms of
post traumatic stress disorder include feelings of
anxiety or intrusive thoughts about the traumatic
event.
Schoenfeld:
When something
has human malicious intent, it's weighted very heavily
towards producing a much more powerful psychological
reaction in us than something that's more neutral
- even if it's very destructive.
Narrator:
For Science Today, I'm Larissa Branin.
C.
The Threat of a Tree-killing Pathogen
Narrator:
This is Science Today. A tree-killing disease known
as sudden oak death which has infected and killed
tens of thousands of California's central coast oak
trees, has been found to not only have the potential
to spread East - but may possibly be able to jump
to a different species. There's been preliminary data
suggesting the killer spores may infect redwoods as
well. David Rizzo, a plant pathologist at the University
of California, Davis says sudden oak death was first
discovered in California in the mid-Nineties.
Rizzo:
We think the main cause of sudden oak death is
a fungus or fungus-like organism known as Phytophthora
and that is what initially gets in there. It can kill
trees on its own, but often it will stress trees that
other organisms can also come in.
Narrator:
Rizzo warns that visitors in infected areas may inadvertently
carry off spores from the soil.
Rizzo:
So if somebody is doing off road driving and getting
mud in the tires, before they head to an area that
does not have the disease, they should probably run
their car through a car wash to get the mud off their
tires.
Narrator:
For Science Today, I'm Larissa Branin.
D.
Researchers Work to Develop Alternative Fuel Sources
Narrator:
This is Science Today. The U.S. Department of Energy
is working on a plan that would eventually replace
the internal combustion engine in favor of hydrogen-based
fuel cells to power cars of the future. One of the
limitations of hydrogen production has been that it's
done in a non-renewable manner. But University of
California, Berkeley plant biologist Tasios Melis,
discovered a metabolic switch within green algae cells,
which triggers the production of large quantities
of hydrogen gas.
Melis:
And this metabolic switch, when activated, permits
the algae to produce hydrogen instead of oxygen.
Narrator:
This works
by depriving the algae of sulfur, which causes the
algae to cease production of oxygen.
Melis:
And
after a short period of time, they activate the alternative
pathway - the result of which is the production of
hydrogen. So I think that's where our contribution
is significant, because we have a process based on
the biology of green algae and this process permits
the production and accumulation of significant amounts
of hydrogen.
Narrator:
For Science Today, I'm Larissa Branin.
E.
Early Studies Find Gender Differences in the Brain
Narrator:
This is Science Today. It's been long assumed that
men and women think differently, but it took some
time to find a biological basis for this theory. Now
a number of studies are confirming there are indeed
gender differences in the brain. At the University
of California, Irvine, for example, Dr. Larry Cahill
has used PET scans to trace the brain activity of
men and women watching movies and discovered they
use different sides of a small brain structure called
the amygdala to store emotional memories.
Cahill:
As things get more emotional, men are tending to remember
more of the central aspects of a story at the expense
of the peripheral details - whereas women are tending
to remember both a little better. Men seem to have
a very different pattern. As things get more emotional,
they seem to be focusing in like a flashlight beam
on the gist of the story more at the expense of the
details.
Narrator:
These results are preliminary and more study is needed.
Cahill:
What this study essentially does is document that
there is this sex-related laterality of function going
on.
Narrator:
For
Science Today, I'm Larissa Branin.
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