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A.
A Crop Protection System Worth Crowing About
Narrator: This is Science Today. Hungry crows can be a major threat to almond crops, so researchers at the University of California , Davis have developed a simple, cost-efficient device to make this problem fly away. Study leader Michael Delwiche says the battery-operated electronic unit plays four different recordings of crow distress calls at timed intervals to spook the real ones away from the almond crops.
Delwiche: The unit was designed to turn on during the day, to shut off at night, so that it had good power management. And it's on a stainless steel hook and you hang it on a branch on the almond tree at about, anywhere from four to six feet and it'll run easily two months without needing recharge.
Narrator: In California almond orchards, Delwiche says crows can cause up to a thousand dollars per acre in crop damage in a single season.
Delwiche: In some orchards, they are a real problem. They can actually come in and virtually decimate the crop. That really was sort of the precipitating factor for this research.
Narrator: Broadcast distress calls have been used for over a decade to chase away crows, but this device was designed to save power and prevent the birds from getting used to the calls. For Science Today, I'm Larissa Branin.
B.
A Tropical Forest Study Reveals Nature Encourages Diversity
Narrator: This is Science Today. An analysis of seven tropical forests around the world reveals that nature encourages diversity by selecting for less common trees as the trees mature. Biology professor, Christopher Wills, of the University of California , San Diego , led the study.
Wills: People of course have been questioning why diversity should be maintained. They've been proposing theories for why it should be maintained, but there's been very little good hard evidence about what impact is going on at the ecosystem level. So our study shows that these processes really are happening in a wide variety of different ecosystems in the tropics.
Narrator: In forests throughout the New and Old World tropics, Wills found that older trees are more diverse than younger ones – meaning, diversity is actually selected for as each of the forests mature.
Wills: Now that we've established that there are active processes going on, we can begin to ask how can we decide among the various theories that help to explain this diversity?
Narrator: For Science Today, I'm Larissa Branin.
C. Careful Planning Helps Transition from Conventional to Organic Production
Narrator: This is Science Today. Farmers can make a smooth transition from conventionally-grown crops to organic production with careful planning and by diversifying their crops. Those were the findings of a three-year, nationally-funded study led by Louise Jackson, a specialist in the Department of Land, Air and Water Resources at the University of California , Davis .
Jackson : One of the things that they did was they greatly diversified their crop mix. Normally the main crops they grow on much of the conventional land in the area is lettuce, broccoli, cauliflower, spinach, celery and during the organic transition, they used many more different kinds of crops, and cover crops. And not only diversify, but go for smaller-scale plantings
Narrator: Jackson adds that planting at certain times of the year to avoid pests was also important.
Jackson : They carefully looked at the types of pests that might occur in the area and they purposely set planting dates so that they would not coincide with some of the greatest potential pest outbreaks.
Narrator: For Science Today, I'm Larissa Branin.
D. When it Comes to Asthma, No Man is an Island
Narrator: This is Science Today. Lower socioeconomic factors and urban areas have been linked to higher rates of asthma, but new research showed poorer lung function among populations living in the suburbs. Dr. Paul Blanc, a professor of occupational and environmental medicine at the University of California , San Francisco , led the study.
Blanc: Surrounding areas of lower socioeconomic status were associated with worse quality of life specific to asthma, but when we looked at lung function and how fast someone can exhale air, which is a common measure of disease status in asthma, we actually found that what predicted worse lung function was surrounding socioeconomic status that in general, one would associate with a suburban, less dense population picture and home ownership.
Narrator: The study raises the possibility that higher rates of pet ownership and larger backyards with more allergenic plants could be a factor in suburban-related health exposures. For Science Today, I'm Larissa Branin.
E. A Study Reveals Fish Have Menopause
Narrator: This is Science Today. For the first time, a team of researchers at the University of California , Riverside has determined statistically that fish have menopause and that it's not affected by evolution. Biologist David Reznick, who
led the study, says their research of guppies in Trinidad may have implications for humans.
Reznick: For animals in general, what it says is that menopause may not be in any way a product of natural selection. In the case of humans, it's been argued at great length that human menopause is something that's been shaped by evolution and that in fact, it's an adaptive feature of our life cycle – that women live well beyond their capacity to reproduce because of what's been referred to as a ‘Grandmother Effect'.
Narrator: That's the evolutionary concept that grandmothers enhance the ability
of their daughters to reproduce and affect the survival of their grandchildren.
Reznick: Our data argue that menopause may just be a by-product of how the animal's put together and the earlier life history of the animals. And so, in the
case of a guppy, the only reason for them to live beyond the end of their ability to reproduce is because different parts of the body age at different rates.
Narrator: For Science Today, I'm Larissa Branin.
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