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Past Shows
April 29, 2006
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Chernobyl's Legacy
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Barn swallows at Chernobyl - Courtesy, Dr. Timothy Mousseau |
It was the world’s worst nuclear disaster, and now, two decades later, the terrible legacy of Chernobyl is still being measured. On the 20th anniversary of the explosion at the Soviet nuclear plant, experts still can't agree on the lasting impact of the accident that occurred on April 26, 1986. While some reports paint an optimistic picture of an ecosystem on the rebound, a Canadian scientist who has studied the situation for the past decade says it's much more complicated and worrisome. Dr. Timothy Mousseau, a professor of biological sciences at the University of South Carolina, says the effects on humans and animals have been underestimated, and he uses his own studies on barn swallows in Chernobyl to show how long-term DNA mutations have lowered survival rates.
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Hyena Hormones
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Spotted hyena and cubs in Kenya - Courtesy, Dr. Kay Holekamp |
Female hyenas have some interesting adaptations which give them many characteristics we think of as male. They're large and aggressive, and try to dominate other hyenas. They even have a large, penis-like sexual organ which they use in dominance displays. They also compete strongly for position in the matriarchal hierarchy that rules hyena packs. Dr. Kay Holekamp, a professor of Zoology at Michigan State University, has been studying the hyena for more than a decade. She's discovered another interesting adaptation. Female hyenas give their offspring a blast of male hormones before birth, which helps stir their offspring to stereotypically male behaviours like aggression and "mounting" -- a type of sexual play.
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Mosquitos vs. Malaria
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Mosquitos being fed malaria infected blood - Courtesy, Dr. K. Vernick |
We've known that only Anopheles mosquitos carry malaria and infect humans with their bite, but new research shows that not all of them do. Dr. Ken Vernick, a professor of Microbiology at the Centre for Microbial and Plant Genomics at the University of Minnesota, and his colleagues have discovered that a large proportion of these mosquitos actually possess a genetic resistance to the malaria parasite. These insects actually kill the parasite as soon as it enters their body, so they can't pass the disease on to humans. It's only those without this genetic ability that serve as vectors of the malaria. Dr. Vernick hopes that we may find ways to encourage this resistance in the entire mosquito population, and thus have a big effect on the rates of infection of this terrible disease.
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Opening the Drake Passage
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Antarctica |
Once warm and green, Antarctica turned icy about 34 million years ago. But researchers have debated the reason behind the dramatic climate change. Now, Dr. Ellen Martin, a professor in the department of geological sciences at the University of Florida, believes she has made a discovery that helps explain the cooling.
By studying fish teeth fossils pulled from sediment deep under the ocean, Dr. Martin has determined that the Drake Passage, which connected the Atlantic with the Pacific Ocean above Antarctica, actually opened 41 million years ago. That's much earlier than some previous estimates, and it means that a cold ocean current was created around the continent before the climate change. She says the date suggests that current of the combined oceans' waters contributed to the dramatic cooling of the continent.
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Artificial Muscles
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Artificial muscle wire lifts a weight - Courtesy, UT Nanotech Institute |
Engineers have never managed to produce a muscle as compact, powerful and portable as human muscle, but Dr. Ray Baughman and his team from the Nanotech Institute and the Department of Chemistry at the University of Texas may have equaled nature's feat, and perhaps even done better. They've developed artificial muscle devices that can be fueled by hydrogen, or even simple alcohol, and can be engineered to have one hundred times the strength of human muscle. If they can be introduced into robotic or prosthetic limbs, they could lead to vast improvements over the devices being used today.
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