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A.
Scientists Develop and Test Instruments that Strengthen
National Security
Narrator:
This is Science Today. In an ongoing effort to strengthen
our nation's defense against terrorism, scientists
at the Lawrence Livermore National Laboratory are
testing commercial instruments and developing new
technologies to detect if nuclear materials have
been smuggled inside cargo containers. Arden Dougan,
a program manager at the Lab, says handheld radiation
detectors are being used for what's called active
interrogation.
Dougan:
The active interrogation method uses neutrons to
go inside the container and that makes the nuclear
material fission and when it fissions, new signatures
of radiation exit the cargo container, we detect
that and from that we can say 'A-ha, there's something
inside." And so we're looking at various techniques
to look inside that container.
Narrator:
This
includes what Dougan calls defense and depth strategies.
Dougan:
It's kind of a layered approach for security, where
you don't just use one super detector that detects
everything inside a container, you have different
kinds of detectors that are each specialized or maybe
overlap what they detect.
Narrator:
For Science Today, I'm Larissa Branin.
B.
A Popular Pesticide Linked to Reproductive Defects
in Frogs
Narrator:
This is Science Today. Scientists from the Environmental
Protection Agency are recommending that the agency
conduct more research on atrazine, a widely used pesticide
that has been linked to causing sexual abnormalities
in frog populations. Tyrone Hayes, a researcher at
the University of California, Berkeley, conducted
previous studies on atrazine, suggesting that low-level
exposures caused tadpoles to develop into frogs with
both male and female reproductive organs.
Hayes:
We are confident in the laboratory that atrazine induces
the mixed-sex problem - the hermaphroditism that includes
feminization and demasculinization. We have good correlative
evidence in the field that animals that are exposed
to atrazine also show this problem in real life.
Narrator:
Atrazine is banned in seven European countries,
but is widely used by farmers in the United States.
Hayes:
It's the number one selling herbicide in the world
and in the United States we use somewhere between
60 and 150 million pounds a year - there's virtually
no atrazine-free environment.
Narrator:
For Science Today, I'm Larissa Branin.
C.
Fuel Cell Vehicles: A Potential Power Supply on Wheels?
Narrator:
This is Science Today. As our nation's energy demands
increase, scientists at the Lawrence Berkeley National
Laboratory are dreaming up exciting ways to reduce
the load on the overall utility grid. Staff scientist
Chris Marnay says one enticing suggestion is to combine
the use of microgrids, or a small cluster of on-site
generators, with fuel cell vehicles.
Marnay:
You can imagine a situation in which people drove
electrically powered vehicles, or fuel cell vehicles,
or battery vehicles to work and then plug them in
at their office and they became part of a microgrid
at their office.
Narrator:
With this design, fuel cell vehicles could drive onto
a site with a microgrid, park and plug in, and then
potentially supply power to a few homes or offices.
Marnay:
So fuel cell vehicles are interesting in this way,
because what could be a better way of avoiding congestion
on the power system than for people to take their
own power supply around with them?
Narrator:
For Science Today, I'm Larissa Branin.
D.
What Expectant Parents Should Know about Prenatal
Ultrasound
Narrator:
This is Science Today. For many expectant parents,
having a prenatal ultrasound means getting an exciting
first peek at their baby, but as a diagnostic test,
ultrasounds are extremely important for predicting
birth outcomes and risks. Rebecca Smith-Bindman, a
researcher at the University of California, San Francisco,
explains.
Smith-Bindman:
I think patients have started to look at ultrasound
in a way that it's just a fun test that they have
to see a picture of their baby and I'm very sympathetic
with that view of ultrasound. But it's really a medical
test and really has a very important medical role
for predicting who's really at greatest risk.
Narrator:
Smith-Bindman
suggests getting an ultrasound as early as 15 weeks
gestation, instead of the routinely recommended 20
weeks, so that babies in highest-risk groups can be
identified earlier.
Smith-Bindman:
If we could identify those fetuses who are greatest
risk, we can then have more success in trying to develop
interventions that can help them.
Narrator:
For Science Today, I'm Larissa Branin.
E.
How Bovine Biosensors May Help Dairy Farmers
Narrator:
This is Science Today. Biosensors similar to those
used to monitor astronauts are on the horizon in animal
agriculture. Bioengineering professor Michael Delwiche
of the University of California, Davis, says this
type of technology may be developed for dairy farmers
in the next 10 to 20 years to monitor the chemical
composition of milk or for breeding purposes.
Delwiche:
One of the real issues that dairy farmers have is
to detect when a cow is in estrus and when the cow
is in estrus, then they know that they have to breed
the cow. It's a judgment call and they don't always
get it right, in fact frequently they get it wrong.
Narrator:
So UC biochemical engineers are working with animal
hormone scientists to develop a nature-mimicking technique
that's based on progesterone levels.
Delwiche:
Progesterone is a steroid hormone and it's released
by the ovary, so what we do is we watch the progesterone
level starts to drop off. When it gets below a threshold,
we know that there's going to be surge of other hormones
and ovulation is gonna happen.
Narrator:
For
Science Today, I'm Larissa Branin.
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