【速度1-7】之前越障老是发在速度前面。。。这次终于改过来了
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StudyingWhite Roofs as a Way to Reduce Urban Heat
BOB DOUGHTY: This is SCIENCE IN THE NEWS,in VOA Special English. I'm Bob Doughty. FAITH LAPIDUS: And I'm Faith Lapidus. This week, we will tell about the medical condition known as atrial fibrillation. We also will tell about two studies of sea birds, and how a change of color could help fight rising temperatures. And, we will tell what officials in California have doneto protect historic objects on the moon. (MUSIC) BOB DOUGHTY: Atrial fibrillation produces an abnormal heartbeat.People feel their heart race and they lose their breath. The problem may last afew seconds, but it can get worse and worse with age, leading to a heart attack or stroke. Doctors generally treat atrial fibrillation with drugs. But arecent study shows that another treatment may have better results for patients who were not helped by drugs. The treatment is called catheter ablation.Doctors place a long thin tube called a catheter into the heart. Then they useradio frequency energy to heat the tissue around the catheter. The heat burnsoff a small amount of heart muscle. The goal is to block abnormal electrical activity in the heart. FAITH LAPIDUS: Researchers studied more than one hundred fifty patients whose condition had failed to improve after taking at least one drug.In the study, about one hundred of the patients had catheter ablation. The others were treated with more drugs. There was a nine-month follow-up period to compare the effectiveness. David Wilber of Loyola University Medical Center in Illinois wasthe lead writer of a report about the study. He says catheter ablation worked in sixty to seventy percent of the patients. By comparison, abnormal heartbeats returned in eighty to ninety percent of those treated with drugs.
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Doctor Wilber says catheter ablation is notmeant to be the first treatment choice for atrial fibrillation. He suggests itonly when drug therapy fails to work. The report appeared in the Journal of theAmerican Medical Association. (MUSIC) BOB DOUGHTY: A report in the journal Current Biology says fishand other food thrown from boats can influence the movement of birds. A team of scientists used satellite information about a fishing area near the Mediterranean coast of Spain. Satellite images followed the travels of twokinds of seabirds: the Cory's shearwaters and the Balearic shearwaters. The team learned that the birds traveled one way on days when fishing was permitted, and another way when it was not. The scientists kept detailed records of the birds' travel over anumber of flights. The trips lasted an average of about two days. Some birdsflew ten kilometers during that time. But others traveled up to one thousand kilometers. The birds traveled longer distances when they did not see fishingboats. The birds spread out from one another to do this, and they spread with increasing speed. FAITH LAPIDUS: The lead scientist was Frederic Bartumeus of the Center for Advanced Studies of Blanes in Spain. He calls the actions of the seabirds, a superdiffusive process. The process let them look effectively for small hake and other fish that move often and unpredictably. But when the birds sawfishing boats, they looked for food near the boats. That reduced their spreading action and slowed their speed. Professor Bartemeus says the study shows how human activities inthe natural environment can change the travels of other organisms. The scientists say their findings may help the study of invasive species.
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BOB DOUGHTY: In another study, some brown pelicans on the west coast of the United States have been acting mysteriously.About twenty thousand brown pelicans fly south from the American state of Oregon each winter. Experts say the birds usually have flown to southern California or Mexico by this time of year. But, during the past three years,some have failed to fly south. Uncounted numbers of pelicans have remained in Oregon. Many are thought to have died of cold or hunger or in severe storms. Wildlife rescuers in Oregon say some of the birds have been seen around restaurants and cafes. Even when people are present, the birds reportedly eat food that has been thrown away. And, people have been seen feeding them. Experts say pelicans usually fear human beings. They urge peopleto leave the birds alone. (MUSIC) FAITH LAPIDUS: Large cities are known to have higher temperatures than rural areas in summer months. This extra heat can raise temperatures incities by about one to three degrees Celsius compared to rural areas. Scientists say there are many reasons for this. One reason is that heat from the sun can go through many of the building materials commonly found in cities. One such material is asphalt, a substance often placed on topof buildings and used to cover road surfaces. BOB DOUGHTY: Recently, American researchers studied ways toreduce the heat in developed areas. Scientists with the National Center forAtmospheric Research led the study. They found that painting the tops of buildings white could possibly help to cool cities and slow the effects of climate change.
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The researchers used a computer model that predicted the effects of the sun's heat. They compared the effects of black surfaces on rooftops with white roofs. They found that a city with only white rooftops could reduce the urban heat effect by thirty-three percent. FAITH LAPIDUS: However, white roofs could have the opposite effect in winter. That is because they have a cooling effect within buildings.Cooler building temperatures in the winter could require more energy to heatthe buildings. The researchers found that some cities would be helped more than others from white roofs. This would depend on the total surface area of roofsin a city. It would also depend on the building materials used since some materials are less resistant to heat than others. The researchers say whiteroofs would work best in areas with warm climates and strong sunlight all year. The team's findings were published in the Geophysical Research Letters. America's National Science Foundation paid for the study. BOB DOUGHTY: Scientists say more information is needed beforethey can be sure that painting roofs white would help battle risingtemperatures. Keith Oleson was the lead writer of the report. He says the studyshows that, in theory, white roofs could be effective in reducing urban heat.However, he says, it remains to be seen if it is possible for cities to painttheir roofs white. (MUSIC) FAITH LAPIDUS: Finally, the state of California is far away fromthe moon. But California officials recently registered objects left by thefirst men to land on the moon's surface. The state's historical resources agency recognized the more than one hundred objects as historicallyprotected. California has a deep interest in the objects. Many state-based companies helped develop machines and equipment that made the moon landingpossible.
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BOB DOUGHTY: Americans Neil Armstrong andEdwin "Buzz" Aldrin landed on the moon on July twentieth,nineteen-sixty-nine. The two astronauts explored an area that they called"Tranquility Base." Lack of space in their lunar spacecraft, the Eagle, forced them to leave equipment on the surface. The lower half of the spacecraft, or landing vehicle, still lies there today. So do empty food containers, space boots, life support systems andan American flag. They were just a few of the things the astronauts leftbehind. The total weight of equipment remaining on the lunar surface is about two thousand two hundred sixty eight kilograms. FAITH LAPIDUS: Some scientists support the idea of historical protection for the remaining objects. They hope that someday Tranquility Basewill be named a United Nations World Heritage Site. But the current California action registers only the objects, not Tranquility Base. International law barsany nation or state from claiming lunar surfaces. Beth O'Leary is a professor at New Mexico State University. MizO'Leary is a supporter of honoring space heritage. She expresses concern thatpeople traveling in space might someday damage the spaceflight objects. At the moment, however, that threat does not seem immediate. Abudget proposal by President Obama cancels the American space agency's plansfor manned space flights to a lunar station. At least for awhile, historic objects on the moon remain far away and safe from human hands. (MUSIC) BOB DOUGHTY: This SCIENCE IN THE NEWS was written by Jerilyn Watson, Caty Weaver and Brianna Blake, who was also our producer. I'm Bob Doughty. FAITH LAPIDUS: And I'm Faith Lapidus. Join us again next week for more news about science in Special English on the Voice of America.
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发表于 2018-9-13 09:59:46
楼主
练习速度，一分钟完全读不完怎么办。。大概扫过一遍的话就不太懂这个部分讲的啥..所以速度练习是相当于练习略读？