A. Detecting a Basic Constituent of Matter
Narrator: This is Science Today. An international group of physicists has for the first time detected a basic constituent of matter. Research physicist Ann Heinson of the University of California, Riverside, co-led the search for top quarks.
Heinson: A top quark is an elementary particle. It's one of a small number of particle types that makes up the universe and it's the heaviest known of those particles. One top quark is as heavy as a gold atom, which has many protons and neutrons in a nucleus and a top quark is just a point-like particle, but nonetheless, it's a very heavy thing.
Narrator: This discovery was made using the Tevatron Collider, the world's highest energy particle accelerator and it produced a top quark without the simultaneous production of its antimatter partner – an extremely rare event.
Heinson: Although what we're doing is understanding a very small piece of the whole big picture, it is nonetheless a very critical piece and it helps to explain, in a mathematical way, how things interact in the universe and one can use those models to understand the beginning of the universe.
Narrator: For Science Today, I'm Larissa Branin
B.
Oceanographers Go Inland to Seek Clues about the Climate System
Narrator: This is Science Today. Oceanographers and meteorologists from the University of California, San Diego 's Scripps Institution of Oceanography are traveling further inland to better understand the climate system. In the Sierra Nevada mountain range, these scientists are studying old trees because records of growth in tree rings provide clues to long-term natural cycles of drought and heavy rains. Dr. Wolf Berger, a professor of oceanography at Scripps, says historical weather records have not provided very much information.
Berger: The problem, especially here on the West coast, is that are records are not very good. That what people have measure and what they have written down usually goes back fifty years in any detail and maybe a hundred years with less detail. And that we'd really like to know what things are like over 200 year period, 300 year period – maybe over a thousand years.
Narrator: The researchers can take samples from living trees known to be sensitive to weather change by using thin cores that can be bored without hurting the tree. For Science Today, I'm Larissa Branin.
C.
Ensuring the Postharvest Qualty & Safety of Fresh Fruits and Vegetables
Narrator: This is Science Today. University of California scientists are working with California growers and livestock producers to ensure postharvest quality and safety of fresh fruits and vegetables. Trevor Suslow is a postharvest specialist at the University of California, Davis.
Suslow: What we try and do is really take a system approach to the kind of risk and also the types of control measures or prevention practices that you would have to have to go as far as you can to assure a safe food supply.
Narrator: This includes assessment of water use, manure, soil amendments, foliar sprays and where crops are grown in relationship to other types of adjacent land activities.
Suslow: What happens at harvest, what happens during the cooling and cleaning and washing, as well as any events during the distribution to a food service or a retail outlet. So, it's really looking at the continuum and trying to break down all of the different, possible points of entry for contamination and options to limit that contamination or to prevent it from surviving or growing.
Narrator: For Science Today, I'm Larissa Branin.
D.
Can One Become Immune to Contaminated Drinking Water?
Narrator: This is Science Today. Immigrants from developing countries often become sick when visiting their countries of birth. According to Marylynn Yates, a professor of environmental microbiology at the University of California, Riverside, the cause of sickness is usually from drinking contaminated water.
Yates: Some microorganisms, once you're exposed to the organism, you actually develop a lifelong immunity. Other organisms, it's very short-lived and so you can be exposed to it, get sick, have a very short-term immunity, be exposed to it again and get sick again.
Narrator: Yates says the children of immigrants who were born in developed countries are most vulnerable to sickness because they have never been exposed to contaminated drinking supplies. Yates' tip – drink bottled water when traveling in countries where you are unsure of the water quality.
Yates: If you don't have the immunity or if you've lost the immunity, you will very likely get ill if you're exposed to those organisms. So, you do have to exercise common sense.
Narrator: For Science Today, I'm Larissa Branin.
E.
New Insight into the Link Between Infection and Asthma
Narrator: This is Science Today. It's been known that there is a clinical link between various types of infection, either viral or bacterial, and serious asthma attacks. Dr. George Caughey, a professor of medicine at the University of California, San Francisco says the real question is why asthma is provoked by infection.
Caughey: We were interested in exploring the reason. I mean, what are the inflammatory mediators involved, which could be targets for drug treatment?
Narrator: In mice studies, Caughey discovered that histamine, an inflammatory compound released during allergic reactions, can be produced in large quantities in the lung by white blood cells, or neutrophils. These cells are the major component of pus, a fluid found in infected tissue. It was previously thought that lung histamine was produced by mast cells, which are classically associated with allergies.
Caughey: It suggests that if this phenomena also occurs in humans, that targeting histamine made by neutrophils might be a strategy to reduce the severity of attacks.
Narrator: For Science Today, I'm Larissa Branin.
