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VOICE ONE:
I’m Steve Ember.
VOICE TWO:
And I’m Bob Doughty with the VOA Special English program Science in the News. This week — a test of an AIDS vaccine produces some mixed results that scientists call surprising. Scientists find evidence of a four-winged dinosaur in China. And we tell you the one invention that some Americans say they could not live without.
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VOICE ONE:
An experimental drug had no effect in general in the first major test of a vaccine to prevent AIDS. But the news was not all bad. The researchers say the product Aidsvax seemed to show promise in blacks and Asians.
Africa has suffered the worst from AIDS. The crisis in Asia grows. The vaccine, though, was designed to fight the forms of HIV common to North America and Europe.
A company in California, VaxGen, tested Aidsvax to see if it could protect people from H-I-V, the virus that causes AIDS. One group of people took Aidsvax. A smaller group took a placebo, an inactive substance. In the end, the researchers found only about four percent fewer cases of infection among those who had taken the Aidsvax.
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Four percent would not be good enough to gain approval for widespread use. But VaxGen reported much higher protection rates in blacks and Asians.
In the United States, black people have about half the new cases of H-I-V each year.
Only two percent of blacks in the study who took the vaccine became infected with H-I-V. This compared with an infection rate of more than eight-percent in blacks given the placebo. The vaccine protected Asians and people of mixed race almost as well. But the study found no effect on whites including Hispanics.
VOICE ONE:
Some experts say genetic differences may be the explanation. Others say the results could be misleading. That is because the study included only a small percentage of minorities.
Five-hundred blacks, Asians and other non-whites took part. In all, the study involved more than five-thousand men at high risk of H-I-V infection and three-hundred high-risk women.
The study took place in the United States, including Puerto Rico, and in Canada and the Netherlands. The people received seven injections over a period of three years.
VOICE TWO:
Aidsvax uses a copy of a protein found on the surface of the H-I-V virus. This antigen called g-p-one-twenty is the same protein that helps the virus join with cells of the body’s defense system. These defenses normally produce antibodies to fight infections. Aidsvax was designed to start this reaction in the hope to fight off any future H-I-V infection.
The World Health Organization says more research on the vaccine is needed.
Anthony Fauci [FOW-chee] directs the National Institute of Allergy and Infectious Diseases in Bethesda, Maryland. He said his agency would test blood cells of people from the study. Institute researchers want to identify what blood cell parts protect against the infection.
In nineteen-ninety-four, the institute decided not to support a large trial of the experimental vaccine. So VaxGen was formed to carry out the work. Doctor Fauci praised the company for its study.
So did the director of AIDS vaccine research for the Joint United Nations Program on H-I-V/AIDS. Jose Esparza said this is the first time a vaccine has been shown to protect humans. Doctor Esparza said more tests — especially in Africa — are extremely important.
VOICE ONE:
The publication “The Scientist” says nineteen other vaccines against AIDS currently are being prepared for tests on people. One product being tested in London and Kenya is showing promise. Scientists at the University of Oxford and the University of Nairobi developed it after research on sex workers in Nairobi. These workers are in continual danger of getting H-I-V but have not become infected.
And, later this year, the VaxGen company is expected to announce results of testing on a vaccine in Thailand that is similar to Aidsvax.
VOICE TWO:
H-I-V stands for human immunodeficiency virus. It is carried in body fluids. It can spread between people through sex or by sharing infected needles or other sharp devices. It can also spread from mother to baby.
AIDS is Acquired Immunodeficiency Syndrome. It robs the body of its protections against disease.
Experts agree that science is making progress against AIDS, a disease first identified twenty years ago. So far, there is no cure, but there are medicines that can suppress the virus. But while experiments continue, millions become infected and millions die.
U-N AIDS estimates there were more than four-million new H-I-V infections worldwide last year — and three-million deaths. An estimated forty-two-million people were living with the virus.
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VOICE ONE:
You are listening to the VOA Special English program Science in the News. This is Steve Ember with Phoebe Zimmerman in Washington.
A discovery in China may give us a better idea how flight began. Scientists found evidence of a one-meter-long animal they call Microraptor gui. This dinosaur lived nearly one-hundred-thirty-million years ago. The fossil remains show it had four legs with wings on each of them. Feathers covered these wings as on modern birds. Microraptor gui also had a long feathered tail.
Researchers from the Chinese Academy of Sciences say this is the first dinosaur ever found with this kind of body structure. They discovered the fossil evidence in Liaoning Province, north of Beijing.
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Experts widely accept the idea that dinosaurs are ancestors of modern birds. Some birds, after all, do look like little dinosaurs. What is not clear, however, is exactly where Microraptor gui fits into the historical development of birds and dinosaurs.
The discovery in China has renewed debate over how dinosaurs might have developed into birds. One theory suggests that dinosaurs learned it was easier to travel from tree to tree if they used their wings. Another theory says they used their wings to gain running speed to take off from the ground. This is called the “ground-up” theory.
VOICE ONE:
Microraptor gui might have had trouble running and beating its wings at the same time. Its wings, remember, were on its legs. So its design would seem to support the tree-to-tree theory of flight.
However, the Chinese scientists say the creature probably did not fly simply by beating its wings. They believe it used both sets of wings to glide, without power, from tree to tree. That is how modern flying squirrels travel through the air.
VOICE TWO:
A separate finding, though, supports the ground-up theory and adds to the debate over the birth of flight. An American biologist studied modern African birds called chukars. Chukars do not fly very well. They live on the ground and have legs that could be mistaken for those of a small dinosaur.
Kenneth Dial of the University of Montana carried out a series of experiments. He discovered that chukars use their wings to break up airflow around their bodies as they run up hills. This helps them keep their feet on the ground. Mister Dial says small, feathered dinosaurs might have used this same method to climb trees to escape danger and later fly.
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What do you think is the one invention that Americans would not want to live without? A computer? Maybe an automobile?
Some Americans were asked to name the one invention that is most important in their daily life. They had five choices – the toothbrush, the car, the personal computer, the wireless telephone or the fast-cooking microwave oven.
VOICE ONE:
The toothbrush received more votes than any other invention. Almost half the adults questioned said they could not live without the small brush they use to clean their teeth everyday. One-third of the young people questioned agreed.
The toothbrush is not even a modern invention. It is credited to the Chinese in the late fifteenth century.
VOICE TWO:
Cars came in second place, followed by computers, mobile telephones and microwave ovens.
Four-hundred teen-agers and more than one-thousand adults answered these questions. It was part of a project by the Lemelson-M-I-T Program. Inventor Jerome Lemelson wanted young people to express new ideas and create new technology.
VOICE ONE:
The people questioned for this year’s report were also asked about events they believe possible in their lifetimes. Many said they believe cars powered by the sun will replace gasoline-powered cars. And most said they believe science may be able to invent a cure for cancer.
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VOICE TWO:
Science in the News was written by Jerilyn Watson, Jill Moss and Karen Leggett. It was produced by Mario Ritter. This is Bob Doughty.
VOICE ONE:
And this is Steve Ember. Join us again next week for more news about science in Special English on the Voice of America.