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A.
The Melting Point of Iron at Earth's Core
Narrator: This is Science Today. Scientists at the Lawrence Livermore National Laboratory have determined that the melting point of iron at the Earth's core is over 87 hundred degrees Fahrenheit. Physicist Jeffrey Nguyen generated conditions similar to that at the core of the Earth by using a two-stage gas gun to launch a projectile at a target that reached a velocity of eight kilometers per second.
Nguyen: People have done similar experiments twenty years ago. What we have done that's different is that we measure really pure iron and that eliminates some of the uncertainties that other people have observed in the past.
Narrator: Understanding the conditions at the Earth's core is key to understanding what drives events like the drifting of continents.
Nguyen: It's very relevant in California because you have earthquakes and that comes from the tectonic shift of the plates and the temperature in the core determines how it interacts with the mantle material and that's what's causing the convection in the mantle and that's driving the tectonic shift.
Narrator: For Science Today, I'm Larissa Branin.
B.
Good News for Mothers Who Breastfeed
Narrator: This is Science Today. A new analysis found that babies who are breastfed for even a short amount of time have a lower risk of developing childhood leukemia. Marilyn Kwan, who led the University of California, Berkeley study, says while this is encouraging for mothers, it's not meant to alarm women who do not or can not breastfeed.
Kwan: This is an epidemiologic study and I think it certainly is helpful if you do breastfeed, but if you don't, it's not something you need to be worried about.
Narrator: Kwan says that's because even though childhood leukemia is the most common childhood cancer, it's still a very rare disease.
Kwan: Probably the rates are one in ten thousand. It's not very common and the risk is so low that with what we found here, it's encouraging for moms. It gives kind of a sense of reason for a mom of a childhood leukemia child – what might be some of the causes or what might prevent the disease, but the risk is so low, so there should be any alarm.
Narrator: For Science Today, I'm Larissa Branin.
C.
What You Should Know about Emergency Rooms
Narrator: This is Science Today. A University of California, San Francisco study based on a national survey of nearly 50 thousand adults has found that the biggest factor driving people to seek emergency department care is poor physical and mental health. Study leader, Dr. Ellen Weber, of the university's Division of Emergency Medicine says the study also found that – contrary to popular perception – most of these patients do have health insurance.
Weber: Another problem with that perception is that when there are stories in the media about ambulance diversion, overcrowding, emergency departments closing, most people can turn their head and say, well that's somebody else, that's the uninsured people, that's not me. And I'm not going to be affected by that, but in fact what our study showed is that most of the people who are going to be affected by overcrowding, by ambulance diversion, by closing of emergency departments are going to be middle-class Americans.
Narrator: Weber hopes these findings may lead to policy change. For Science Today, I'm Larissa Branin.
D.
The Development of an Autonomous Pathogen Detector System
Narrator: This is Science Today. In an effort to counter biological and chemical terrorism, scientists have been developing a system called the Autonomous Pathogen Detector System, or APDS. Pat Fitch, manager of the Lawrence Livermore National Laboratory's Chemical and Biological National Security Program, says APDS is a podium-sized detector deployed in places like airports and subways to automatically collect and process data from the environment.
Fitch: The first test it does is an antibody style test, very much like a pregnancy test. These are done in sandwich format, which means there's two sides of the pathogen are both matched and if you get the match, then the probability of the pathogen there is very high. And if we get a positive with the antibody test, the other feature of this system is it then shuttles a little bit of that sample down and we do a DNA-based test, as well as a nucleic acid test.
Narrator: Fitch says thousands of samples have been taken in the field to establish false alarm rates and so far, there have been none. For Science Today, I'm Larissa Branin.
E.
New Insight into a Lethal Cancer
Narrator: This is Science Today. Between 10 thousand and 50 thousand years ago, about two-thirds of the planet's megafauna, or large animals, went extinct. These animals included mammoths, mastodons and saber-toothed cats. Tony Barnosky, a professor of Integrative Biology at the University of California, Berkeley, says during this time period, the climate changed dramatically going from the last Ice Age into our present interglacial.
Barnosky: That also happens to be a time when humans first arrived in various parts of the world, or increased their populations sizes in various parts of the world. 106 So there's this coincidence that the two possible causes and it's been quite a polarized argument as to whether it was all humans versus all climate or something in between.
Narrator: Barnosky says it was something in between … and it could happen again.
Barnosky: We once again are seeing this ramping up of human population pressure with unprecedented climate change.
Narrator: For Science Today, I'm Larissa Branin.
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