California has a deep interest in the objects. Many state-based companies helped develop machines and equipment that made the moon landing possible.
2011年8月22日星期一
Studying White Roofs as a Way to Reduce Urban Hea
2010-3-1
Photo: AP
Pittsburgh, Pennsylvania, skyline with the city's white-roofed convention center in the foreground.
BOB DOUGHTY: Americans Neil Armstrong and Edwin "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.
BOB DOUGHTY: Recently, American researchers studied ways to reduce the heat in developed areas. Scientists with the National Center for Atmospheric 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.
Experts say pelicans usually fear human beings. They urge people to leave the birds alone.
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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.
The scientists kept detailed records of the birds' travel over a number of flights. The trips lasted an average of about two days. Some birds flew ten kilometers during that time. But others traveled up to one thousand kilometers. The birds traveled longer distances when they did not see fishing boats. The birds spread out from one another to do this, and they spread with increasing speed.
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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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 saw fishing boats, they looked for food near the boats. That reduced their spreading action and slowed their speed.
BOB DOUGHTY: Scientists say more information is needed before they can be sure that painting roofs white would help battle rising temperatures. Keith Oleson was the lead writer of the report. He says the study shows 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 paint their roofs white.
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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.
Professor Bartemeus says the study shows how human activities in the natural environment can change the travels of other organisms. The scientists say their findings may help the study of invasive species.
BOB DOUGHTY: Atrial fibrillation produces an abnormal heartbeat. People feel their heart race and they lose their breath. The problem may last a few seconds, but it can get worse and worse with age, leading to a heart attack or stroke.
Beth O'Leary is a professor at New Mexico State University. Miz O'Leary is a supporter of honoring space heritage. She expresses concern that people traveling in space might someday damage the spaceflight objects.
The researchers found that some cities would be helped more than others from white roofs. This would depend on the total surface area of roofs in a city. It would also depend on the building materials used since some materials are less resistant to heat than others. The researchers say white roofs would work best in areas with warm climates and strong sunlight all year.
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.
BOB DOUGHTY: This is SCIENCE IN THE NEWS, in VOA Special English. I'm Bob Doughty.
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