02 October 2007| New Test for H5N1, and New Findings Why Virus Is So Deadly | |
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Scientists continue to look for ways to deal with the deadly form of bird flu virus.
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| Medical workers care for a bird flu patient in Medan, Indonesia, last year |
If successfully marketed, the hand-held device could be used to look for cases in affected areas and help contain outbreaks. Project leader Juergen Pipper says medical or aid workers would know in less than half an hour if a person is infected.
The device tests material collected from a quick swab of a person’s throat. The test uses magnetic force to control individual droplets containing added magnetic particles. The scientists say the droplet itself becomes a little laboratory that can do things like pump, separate and mix.
They note that an increasing number of similar tests are available to process cells, genetic material and proteins.
Juergen Pipper says the device can process complex tasks in a way similar to a traditional biological laboratory. The researchers say it works about ten times faster than current tests for the virus and could cost much less.
The developers think the same idea could also be used to find other viruses, including those that cause AIDS, SARS and hepatitis B.
Their research was published in Nature Medicine.
As of Tuesday, the World Health Organization had counted three hundred twenty-nine cases of the bird flu virus since two thousand three.
Sixty percent of the patients died. Many experts worry that the virus could kill large numbers worldwide if it starts to spread easily from person to person.
Indonesia has had the most cases, more than one hundred, and the most deaths. Last Friday a twenty-one-year-old man from west Jakarta became the eighty-sixth victim. Health officials say they do not know how he became infected.
An international team reported last week that the virus is so destructive, it can even infect unborn children. Researchers studied the bodies of two people killed by h-five-n-one. The study appeared in the Lancet.
They found that the virus caused a surprising amount of damage to the lungs. It also spread to the brain and to the digestive and reproductive systems. Ian Lipkin at Columbia University in New York says one victim was pregnant and the virus had spread to her fetus.
Yet the findings may help point to ways to limit damage by targeting not only the virus itself, but also how the body reacts.
And that’s the VOA Special English Health Report, written by Caty Weaver. I’m Mario Ritter.
02 October 2007| La Brea Tar Pits: Where Animals Lived, and Died, Thousands of Years Ago | |
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I'm Shirley Griffith.
VOICE TWO:
And I'm Steve Ember with EXPLORATIONS in VOA Special English. Today we tell about an unusual scientific research area in the United States.
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VOICE ONE:
To understand why La Brea is an important scientific research center we must travel back through time almost forty thousand years. Picture an area that is almost desert land. The sun is hot. A pig-like creature searches for food. It uses its short, flat nose to dig near a small tree. It moves small amounts of sand with its nose. It finds nothing. The pig starts to walk away, but it cannot move its feet.
They are covered with a thick, black substance. The pig shakes one foot loose, but the others just sink deeper. The more it struggles against the black substance, the deeper it sinks. The pig attempts to free itself again and again. It now screams in fear and fights wildly to get loose. Less than a kilometer away, a huge cat-like creature with two long front teeth hears the screams. It, too, is hungry. Traveling across the ground at great speed, the cat nears the area where the pig is fighting for its life.
The cat jumps on the pig’s back. It sinks its long teeth into the pig’s neck. The pig dies quickly, and the cat begins to eat. Almost an hour passes before the cat is finished. When it attempts to leave, like the pig, it finds it cannot move. The more the big cat struggles, the deeper it sinks into the black substance.
Before morning, the cat is dead. Its body, and the bones of the pig, slowly sink into the sticky black hole.
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Scientists say the story we have told you happened again and again over a period of many thousands of years. The black substance that trapped the animals came out of the Earth as oil.
The oil dried, leaving behind a partly solid substance called asphalt. In the heat of the sun, the asphalt softened. Whatever touched it would often become trapped forever.
In seventeen sixty-nine, a group of Spanish explorers visited the area. They were led by Gaspar de Portola, governor of Lower California.
The group stopped to examine the sticky black substance that covered the Earth. They called the area “La Brea” the Spanish words for “tar.”
Many years later, settlers used the tar, or asphalt, on the tops of their houses to keep water out. They found animal bones in the asphalt, but threw them away. In nineteen-oh-six, scientists began to study the bones found in La Brea. Ten years later, the owner of the land, George Allan Hancock, gave it to the government of Los Angeles. His gift carried one condition. He said La Brea could only be used for scientific work.
VOICE ONE:
Today, the La Brea Tar Pits are known to scientists around the world. The area is considered one of the richest areas of fossil bones in the world. It is an extremely valuable place to study ancient animals. Scientists have recovered more than one million fossil bones from the La Brea Tar Pits. They have identified more than six hundred fifty different kinds of animals and plants.
The fossils are from creatures as small as insects to those that were bigger than a modern elephant. These creatures became trapped as long ago as forty thousand years. It is still happening today. Small birds and animals still become trapped in the La Brea Tar Pits.
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VOICE TWO:
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| A saber-tooth cat at the Page Museum at the La Brea Tar Pits |
The museum has many fossil remains of the huge cats that once lived in the area. They are called saber-toothed cats because of their long, fierce teeth. Scientists have found more than two thousand examples of the huge cats. The museum also has many ground sloths and thousands of fossil remains of an ancient kind of wolf. Scientists believe large groups of wolves became stuck when they came to feed on animals already trapped in the asphalt.
VOICE ONE:
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| Volunteers dig bones from Pit 91 at the La Brea Tar Pits |
Four of the animals were meat-eating hunters. These were the saber-tooth cat, the North American lion, the dire wolf and the coyote. All these animals, except the dog-like coyote, have disappeared from the Earth.
VOICE TWO:
Researchers say eighty percent of the fossils found are those of meat-eating animals. They say this is a surprise because there have always been more plant-eaters in the world. The researchers say each plant-eater that became trapped caused many meat-eaters to come to the place to feed. They, too, became trapped.
Rancho La Brea has also been a trap for many different kinds of insects. Scientists free these dead insects by washing the asphalt away with special chemicals. The La Brea insects give scientists a close look at the history of insects in southern California.
The La Brea Tar Pits have also provided science with interesting information about the plants that grew in the area. For many thousands of years, plant seeds landed in the sticky asphalt. The seeds have been saved for research. Scientists also have found pollen from many different kinds of plants.
The seeds and pollen, or the lack of them, can show severe weather changes over thousands of years. Scientists say these provide information that has helped them understand the history of the environment. The seeds and pollen have left a forty thousand year record of the environment and weather for this area of California.
VOICE ONE:
Many visitors to the tar pits wonder why they produce large gas bubbles. Now scientists from the University of California, Riverside, have the answer. Bacteria in the natural asphalt are eating away at the oil below the surface and producing methane gas. The scientists discovered more than two hundred kinds of bacteria. Most of them were species that were unknown. The bacteria were trapped in soil that was mixed with heavy oil almost twenty-eight thousand years ago.
The bacteria are able to survive in an extreme environment. The scientists say they live in the asphalt with no water, little or no oxygen and many poisonous chemicals. Scientists think the discovery of the bacteria might lead to new methods to clean oil spills and other uses.
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Thousands of visitors come each year to see the fossils that have been found at Rancho La Brea. They visit the George C. Page Museum. Mister Page was a wealthy man who became very interested in the scientific work being done at the tar pits. He gave the money to build the museum and research center.
At the museum, visitors can watch scientists dig bones from La Brea’s Pit Ninety-One. The scientists dig very slowly, using small tools similar to those used by a doctor to examine teeth. They also use toothbrushes and cleaning fluids to help soften and clean away the asphalt.
VOICE ONE:
Visitors to the museum can also see the “fish bowl,” a laboratory surrounded by glass. Here, they can watch scientists do their research. Visitors can watch the scientists clean, examine, repair and identify fossils that are still being discovered. Through this process, scientists are able to answer questions and solve puzzles about animals and their environment from thousands of years ago.
It is exciting to stand only a few meters away and watch scientists clean the asphalt off a fossil that is thousands of years old. Visitors quickly learn why researchers consider Rancho La Brea a very special place.
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VOICE TWO:
This program was written by Paul Thompson. It was produced by Mario Ritter. You can learn more about the La Brea Tar Pits at our Web site, voaspecialenglish.com. I'm Steve Ember.
VOICE ONE:
And I'm Shirley Griffith. Join us again next week for EXPLORATIONS in VOA Special English.
01 October 2007| Jatropha Plant Raises Hopes for Fuel and Poor Farmers | |
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Biodiesel is made from plant oils or animal fats. Producers of this renewable fuel often use oils like soybean or palm oil. But a wild plant called Jatropha curcas (JAT-ruh-fuh KUR-kas) is getting a lot of attention lately.
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| Jatropha plants at the Indian Oil Corporation research and development center at Faridabad in 2006 |
For example, the New York Times recently described projects in Mali to supply electricity to rural villages with generators that can use the fuel.
The Portuguese are thought to have spread jatropha from Central America to other parts of the world centuries ago during their explorations.
Jatropha grows all year. It does not need much water and it can grow in poor soil where other crops fail. Some African farmers use it as borders for their crops. It helps protect the soil and keeps animals away from food crops like a fence. The seeds are poisonous, although in many parts of West Africa the plant has been used to make traditional medicines.
The Royal Tropical Institute in the Netherlands says Mali has more than twenty thousand kilometers of jatropha. A company called Mali Biocarburant processes the nuts into oil for fuel. The project is financed by the Dutch government and private investors.
Internationally, there are concerns about higher food prices and reduced supply as food crops compete with fuel crops. Such concerns are often raised about corn or sugar cane grown for ethanol. Supporters of jatropha say it does not compete with food crops for good agricultural land or harm the environment.
Still, South Africa's agriculture department says it is being careful in studying jatropha. This is what a spokeswoman told the Mail and Guardian newspaper: "Too many lessons have been learned at high cost when plants that promised to be solutions turned into environmental and social disasters for South Africa."
In June, two British companies formed a joint effort to grow more jatropha in southeast Asia, southern Africa, central and south America and India. BP and biodiesel producer D1 Oils say their new company could become the world’s largest producer of the oil by two thousand eleven.
But while the future seems to hold promise, there are no guarantees. Right now, some jatropha farmers are said to be having problems finding buyers for the seeds.
And that's the VOA Special English Agriculture Report, written by Jerilyn Watson. I'm Jim Tedder.
01 October 2007| Health Experts Say Smokers Need a Cigarette Break -- Permanently | |
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This is SCIENCE IN THE NEWS in VOA Special English. I’m Bob Doughty.
VOICE TWO:
And I’m Faith Lapidus. On our program this week, some new information about tobacco smoke -- and it’s not good news.
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VOICE ONE:
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| On October 1, 2002, a local law, the first of its kind in Japan, banned smoking on the streets of Tokyo's Chiyoda Ward |
Many non-smokers would like to have smoking banned where they work. They fear harmful effects from other people's tobacco smoke, also known as secondhand smoke. Business owners often say a ban on smoking would harm their profits. And, smokers say such a ban would interfere with their rights.
In the United States, secondhand smoke causes about three thousand non-smoking adults to die of lung cancer each year. That information comes from a private group, the American Cancer Society.
VOICE TWO:
Recently, the American Journal of Public Health published two reports about secondhand smoke. The Multnomah County Health Department in Oregon and the Oregon Department of Human Services organized one study. The University of Minnesota Cancer Center in Minneapolis assisted them.
The study involved eighty-four non-smokers who worked at restaurants and drinking places in Oregon. Thirty-two worked in businesses that banned smoking. Fifty-two others worked in businesses that permitted smoking. Most worked as servers or prepared drinks. Two thirds of those studied were women.
The researchers asked the non-smokers about how much time they had spent around smokers while away from work. The breath of the workers was tested to make sure they had not been smoking.
VOICE ONE:
Then the researchers tested liquid wastes from the workers. They found a substance called NNAL in the urine. NNAL is a byproduct of NNK, a chemical found only in tobacco products. Other studies have linked NNK to lung cancer. Over time, scientists have identified more than sixty chemicals in tobacco smoke that cause cancer in people and animals.
The researchers tested the urine of the workers before they started their jobs and again as they finished. Those working where smoking was permitted were more likely to have NNK in their urine.The study did not deal with whether secondhand smoke caused health problems in nonsmokers. But last year, the evidence against secondhand smoke caused America's top medical officer to advise banning smoking in buildings.
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VOICE TWO:
The second report in the American Journal of Public Health came from the Public Health Institute in California. The Public Health Institute is a nonprofit organization that says businesses should be free of smoke.
The Institute says employers must keep workplaces safe for employees. It tells employers that they are open to legal action if their environment harms workers.
Margaret Chan is director-general of the World Health Organization. She has urged all countries to pass laws banning smoking in workplaces.
Businesses are not the only places where secondhand smoke is a threat. People who smoke at home should think about the health of others living with them. The American Cancer Society says secondhand smoke causes lung infections in as many as three hundred thousand young children each year.
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VOICE ONE:
The W.H.O. estimates that smoking is responsible for the deaths of five million people each year. At current rates, it says tobacco use could kill ten million people a year by two thousand twenty. Smoking by pregnant women can threaten the unborn. Expectant mothers are more likely to have babies with health problems and low birth weight. Babies with low weight at birth have an increased risk of dying young. They may also suffer health problems.
VOICE TWO:
Older smokers are also at risk. A study in the publication Neurology showed that older adults who smoke face an increased risk of Alzheimer’s disease. Decreased mental health also was more likely in persons who smoked than in non-smokers.
Alzheimer’s patients lose ability to think, plan and organize. After a time they become unable to care for themselves.
Researchers in the Netherlands studied almost seven thousand adults aged fifty-five years or older. Seven hundred six of the adults developed dementia during the seven years of the study. Dementia is a condition that causes a decrease in a person's thinking ability.
Persons who smoked during the study were fifty percent more likely to develop dementia than those who never smoked or had stopped.
VOICE ONE:
Most people know that smoking causes lung cancer. But it also has been proven to be a major cause of cancers of the mouth, esophagus, kidney, bladder and pancreas. Cigarettes are not the only danger. Smokeless tobacco and cigars also have been linked to cancer. But these facts are not enough to prevent people from smoking.
The American Cancer Society says there is no safe way to smoke. It says smoking begins to cause damage immediately. All cigarettes can damage the body. Smoking even a few cigarettes is dangerous.
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VOICE TWO:
Nicotine is a substance in tobacco that gives pleasure to smokers. Nicotine is a poison. The American Cancer Society says nicotine can kill a person when taken in large amounts. It does this by stopping the muscles used for breathing.
The body grows to depend on nicotine. When a former smoker smokes a cigarette, the nicotine reaction may start again. This forces the person to keep smoking.
Studies have found that nicotine can be as difficult to resist as alcohol or the drug cocaine. So experts say it is better never to start smoking than it is to smoke with the idea of stopping later.
VOICE ONE:
Experts say menthol cigarettes are no safer than other tobacco products. Menthol cigarettes produce a cool feeling in the smoker’s throat. So people can hold the smoke in their lungs longer than smokers of other products. As a result, experts say menthol cigarettes may be even more dangerous than other cigarettes.
Other smokers believe that cigarettes with low tar levels are safer. Tar is a substance produced when tobacco leaves are burned. It is known to cause cancer.
America's National Cancer Institute has said people who smoke low-tar cigarettes do not reduce their risk of getting diseases linked to smoking. Scientists found no evidence of improvements to public health from changes in cigarette design and production in the past fifty years.
VOICE TWO:
Is there no way to smoke without harming your health?
The American Cancer Society does not think so. The group wants people to stop or at least reduce smoking. For this reason it organizes the Great American Smokeout every year. The event takes place in November. Local volunteers support the efforts of individuals who want to stop smoking.
The American Cancer Society says blood pressure returns to normal twenty minutes after the last cigarette. Carbon monoxide gas levels in the blood return to normal after eight hours. The chance of heart attack decreases after one day. After one year, the risk of heart disease for a non-smoker is half that of a smoker.
VOICE ONE:
There are products designed to help people reduce their dependence on cigarettes. Several kinds of nicotine replacement products provide small amounts of the chemical. These can help people stop smoking.
Experts also say a drug used to treat depression has helped smokers. The drug is called Zyban. It does not contain nicotine. It works by increasing levels of dopamine in the brain. Dopamine is a chemical that produces pleasure.
VOICE TWO:
Here is some advice from people who have stopped smoking: Stay away from alcoholic drinks. Take a walk instead of smoking a cigarette. Avoid people who are smoking. If possible, stay away from situations that trouble you.
It is not easy to stop smoking. And people never can completely control their own health. But as one doctor advises her patients, becoming a non-smoker is one way to gain control of your life.
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VOICE ONE:
This SCIENCE IN THE NEWS was written by Jerilyn Watson. Brianna Blake was our producer. I’m Bob Doughty.
VOICE TWO:
And I’m Faith Lapidus. Read and listen to our programs at voaspecialenglish.com. Join us again next week for more news about science in Special English on the Voice of America.
