2005-8-22
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VOICE ONE:
This is SCIENCE IN THE NEWS in VOA Special English. I'm Bob Doughty.
VOICE TWO:
And I'm Barbara Klein. On our program this week, we will tell about the man who first confirmed a link between smoking and lung cancer. We also will talk about a large study of vaccines – those medicines used to protect against disease.
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But first, we report on a flight to the planet Mars.
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An American spacecraft is traveling to Mars to collect information about the red planet. The Mars Reconnaissance Orbiter left Cape Canaveral in Florida on August twelfth. An Atlas V launch rocket sent the orbiter on its trip to Mars. The space vehicle is expected to arrive in March of next year. It is to orbit the planet for at least four years.
The orbiter was designed to tell scientists about the weather, climate and surface of Mars. The American space agency hopes to get as much information from it as from all earlier trips to Mars combined.
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Space agency scientists praised the launch. The huge rocket that lifted the orbiter from Earth dropped into the Atlantic Ocean after about four minutes. Less than an hour after the launch, the orbiter separated from the upper rocket, as planned. Then the vehicle quickly established radio communication with its controllers.
The launch came two days after the space shuttle Discovery returned safely to Earth. Space agency officials had planned to launch the orbiter on August tenth. But technical problems caused delays.
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The orbiter's operations are costing more than seven million dollars. The space vehicle will do two main kinds of work. Each will last about two years. Its first job is to study ice on Mars. Scientists say they believe that long ago, the planet was warm and wet. As such, Mars might have supported living things. Now it is dry and cold. There are large areas of frozen water at the opposite ends of Mars. Scientists hope to learn if people could survive conditions there.
Instruments on the orbiter are to examine the atmosphere, surface and below-surface areas of the planet. Two cameras will show images and provide maps of Martian weather. A device called a spectrometer will identify minerals on the ground. Another device, a radiometer, is to measure dust in the atmosphere. Radar that can show areas under the surface of ice and rocks also will be used. The Italian Space Agency supplied the radar.
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The orbiter's second job is to communicate messages between Earth and mechanical devices on Mars. The American space agency has two robotic explorers operating on the planet. The robots Spirit and Opportunity were launched in two thousand three. They can send information to Earth and also receive messages. They do this with the help of satellites placed in orbit around the planet.
Information from the Mars Reconnaissance Orbiter is expected to help the space agency decide where to land two more robot-explorers. A device called the Phoenix Mars Scout will search for organic chemicals. It will be launched in two thousand seven. The Mars Science Laboratory is to be launched two years later.
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Researchers in Denmark say a large study of Danish children shows that vaccines do not weaken a child's natural defense system against disease. Doctor Anders Hviid of the Statens Serum Institute in Copenhagen led the study.
The scientists examined medical histories of more than eight hundred thousand children. The boys and girls were born in Denmark between nineteen ninety and two thousand one. They all took part in a national vaccination program to prevent common childhood diseases. The program provides children with protective medicines every few months for their first eighteen months of life. Then they receive additional vaccines each year until they are five.
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Some health experts had questioned whether the large number of vaccinations could damage the body's natural defense system. There was special concern about combination vaccinations, like the measles-mumps-rubella vaccine. These are three vaccines mixed together in one injection.
Some people have been concerned that the vaccinations might make the immune system work too hard and weaken it. They thought this could leave a child more at risk for diseases not targeted by the vaccines.
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The Danish researchers looked at the children's rates of hospital admissions for treatment of infectious diseases not targeted by the vaccines. Such diseases included diarrhea and the lung infection, pneumonia.
The researchers say they found no increased risk for hospitalizations in the weeks following vaccinations. They found that none of the six kinds of vaccines the children received increased the risk for seven other major infectious diseases.
Some children's health experts say the study provides more evidence that vaccines are safe. They say the results should make parents feel sure about getting their children vaccinated. The study was published in the Journal of the American Medical Association.
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For years, scientists have warned that smoking tobacco is bad for your health. Many studies have linked smoking to lung cancer. One of the British scientists who first confirmed the link died last month. Richard Doll was ninety-two years old. Officials at Oxford University say he died after a brief sickness.
Professor Doll has been praised as one of the most important medical scientists of the twentieth century. His work has been recognized around the world. His studies into the health effects of smoking are said to have saved the lives of millions of people.
The United Nations World Health Organization estimates that one thousand three hundred million people worldwide use tobacco products. Officials estimate that tobacco use is responsible for about five million deaths a year.
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William Richard Shaboe Doll was born in nineteen twelve in Hampton, England. He began studying medicine after failing a mathematics test. He studied at Saint Thomas's Hospital Medical School in London.
Richard Doll served in the Royal Army Medical Corps during World War Two. After the war, he started work at Britain's Medical Research Council. While there, he was asked to investigate why a growing number of people had developed lung cancer.
At first, Professor Doll thought that gasses released from automobiles was the cause. He and other research scientists questioned hundreds of lung cancer patients to find a common link. They found that the only thing the patients had in common was smoking.
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Professor Doll worked with Austin Bradford Hill of the Medical Research Council. They showed that smoking is a major cause of lung cancer. They also showed the risk of developing lung cancer was directly linked to the number of cigarettes smoked.
Their findings were announced in nineteen fifty-one and confirmed in a study published three years later. In nineteen fifty-seven, the Medical Research Council officially accepted the direct causal connection between smoking and lung cancer.
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Professor Doll said he himself stopped smoking because of the findings. He would later produce more evidence of the direct link.
He also showed that smoking could cause many other kinds of cancer and diseases. He investigated evidence linking alcoholic drinking with breast cancer. He studied the harmful effects of radiation. He also wrote papers on electric power lines and peptic ulcers.
Professor Doll was named the top professor of medicine at Oxford University in nineteen sixty-nine. Ten years later, he helped to create Green College, a college for the study of medicine.
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Professor Doll received many awards throughout his life. The World Health Organization honored him for his work. In nineteen seventy-one, Queen Elizabeth made him a knight, one of Britain's highest honors.
Last year, Sir Richard Doll released a follow up study to the one published more than half a century earlier. The study showed that as many as two thirds of people who begin smoking when they are young will later die as a result of the activity.
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VOICE ONE:
This SCIENCE IN THE NEWS program was written by Cynthia Kirk, Jerilyn Watson and Caty Weaver. Cynthia Kirk was our producer. I'm Bob Doughty.
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And I'm Barbara Klein. Join us again next week at this time for more news about science in VOA Special English.