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A.
A Fingerprint of Human Effects on Global Climate
Narrator:
This is Science Today. By studying climate model
experiments, scientists at the Lawrence Livermore
National Laboratory have discovered another fingerprint
of human effects on global climate. Lab scientist
Ben Santer says they found that in the last two
decades, increases in the height of the tropopause
- a transition zone between the upper and lower
atmospheres - are linked to ozone depletion and
an increase in greenhouse gases.
Santer:
There's still uncertainty about the global scale's
sign of the change in tropospheric temperatures.
Our work suggests that the troposphere may well
have warmed and without that warming you couldn't
really get this pronounced increase in tropopause
height.
Narrator:
This
is the first time scientists examined whether observed
changes in tropopause height corresponded with projections
from climate model experiments on greenhouse warming.
Santer:
If the models are even in the ballpark, then
we can expect some large changes in climate over the
next century and it behooves us to try and understand
those changes.
Narrator:
For Science Today, I'm Larissa Branin.
B.
A Microchip that can Detect a Biochemical Attack
Narrator:
This is Science Today. University of California, Berkeley
scientists have created a microchip that can be used
to sound the alarm for a biochemical attack. Yong
Huang, who led the study, says this "canary on
a chip" uses microelectronics to instantly detect
the dying process of a cell.
Huang:The
core part of our technology is a microchip that can
grow cells on it and also incorporate the cell into
this inanimate electrical circuit. As a result we
can very precisely monitor or detect the membrane
integrity, which is a hallmark of cell death.
Narrator:
The idea is, the instant toxins cause
a cell to die, an alarm goes off.
Huang:
You can easily imagine that this kind of technology
could be implemented as a universal cell based toxic
detection device, which is very critical in a battle
against potential biowarfare or bioterrorism.
Narrator:
For Science Today, I'm Larissa Branin.
C.
Mechanical Thinning of Urban Forests: A Barrier Against
Wildfire
Narrator:This
is Science Today. As the recent wildfires in the West
proved, heavy brush and small trees surrounding homes
can make a catastrophic combination. Forestry scientists
are proposing that removing some of the forestland
debris may save many homes. University of California
Area Natural Resources advisor, Michael de Lasaux,
says they've tested small equipment that can remove
small trees and debris and create a defensible space
near a home.
De Lasaux:The
advantages of this equipment is that they're a small
tractor that has the ability to accommodate various
pieces of equipment. It's very small, only six feet
wide, so it can negotiate in and amongst trees fairly
readily without causing damage, but also around the
homes without causing too much concern by the homeowner.
Narrator:Attachments
on this tractor include a small mower, a cutter and
a processor.
De Lasaux:
After we've cut and processed the tree into logs,
we bring in a grapple, the grapple has the ability
to grab onto all these small logs and then carry them
to a place where we'll concentrate them and determine
what next to do with them.
Narrator:
For Science Today, I'm Larissa Branin.
D.
A Doorway to a New Form of Learning
Narrator:This
is Science Today. How do people ultimately get over
their fears? That's a question UCLA researchers are
interested in answering. Mark Barad, a professor of
psychiatry and bio-behavioral sciences, is studying
a process called extinction, which refers to learning
to inhibit fear under circumstances where it's not
appropriate.
Barad:
We believe that by targeting this extinction system,
we would get rid of these excessive fears and what's
nice about it is we're not erasing the ability of
that person to summon up an appropriate fear response
to appropriate dangers - even if it's the same kind
of danger because extinction - this process, is very
context specific.
Narrator:
Barad helped
discover one of the specific molecules involved in
the process of extinction.
Barad:
This is
an important finding and it's like having a doorway
into a new form of learning. The other thing is that
now the difference means that we can now look for
drugs that affect this system in particular and use
those to develop a way to make extinction go faster
without messing up other forms of learning.
Narrator:
For Science Today, I'm Larissa Branin.
E.
The Challenge of Providing a 'Morning After' Pill
for HIV
Narrator:
This is Science Today. AIDS researchers at the University
of California, San Francisco, are studying a little-known
'morning after' drug intervention for HIV exposure,
called post-exposure prophylaxis, or PEP. Dr. Michelle
Roland says that anyone can start PEP within 72 hours
after a potential exposure.
Roland:Any
healthcare provider can provide post-exposure prophylaxis.
These are medicines that are approved for the treatment
of HIV disease and they are covered on all insurance
formularies because they are very standard drugs.
Narrator:
Roland says that although anyone can get PEP, it will
be difficult to popularize the drug treatment because
many doctors aren't familiar with assessing risks
or treating HIV.
Roland:
I think
it's going to be a challenge for clinics, emergency
departments, HIV clinics, STD clinics, to think about
over time whether they want to provide this service
because they will need to develop a group of healthcare
providers who have expertise.
Narrator:
For
Science Today, I'm Larissa Branin.
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