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(单词翻译:双击或拖选)
BOB DOUGHTY1: This is SCIENCE IN THE NEWS in VOA Special English. I’m Bob Doughty.
FAITH LAPIDUS: And I’m Faith Lapidus. Today, we will tell about a United Nations warning about Earth’s natural environments. We will have information about infections linked to hospital stays. We will also tell about a historic record of rainy seasons in Asia, and the search for life on other planets.
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BOB DOUGHTY: Scientists say keeping a count of all the different kinds of plants and animals on Earth is one way to measure the health of our planet. Scientists use the word biodiversity to describe the existence of many kinds of plants, animals and other organisms. One definition of biodiversity is the differences of life at all levels of biological organization.
But a United Nations report has little good to say about the health of biodiversity in the world. The report says national governments have failed to honor a biodiversity protection treaty. As a result, the report says, the rate of plant and animal species disappearing is continuing faster than ever before. Vertebrate species, for example, decreased by nearly one-third between nineteen seventy and two thousand six.
Polar bears, an endangered species, at a zoo in Antibes, France
The report says not one country has met all the biodiversity targets that were set eight years ago. That is when the first Global Biodiversity Outlook report was released. At the time, more than one hundred ninety countries agreed to reduce or halt biodiversity losses by twenty ten.
FAITH LAPIDUS: The U.N. report was based, in part, on one hundred ten national reports on action taken to reduce or stop the loss of biodiversity. The report did note some improvements, like increases in the size of protected land, especially coastal2 areas. But in general, the report says habitat losses outweigh3 the gains. The report says overfishing is a major problem that government rules have done little to stop. It warns of the possible collapse4 of fish species important to the commercial food supply.
The report identifies five main reasons for losses in biodiversity. They are changing habitats, overuse of resources, pollution, invasive species and climate change.
The report will be discussed at a U.N. biodiversity meeting set for October in Nagoya, Japan.
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BOB DOUGHTY: Hospitals not only treat infections. They can also cause them. In the United States alone, the number of infections in hospitals is estimated at close to two million each year. About one hundred thousand patients die.
A government report notes that little progress has been made in reducing what are called health care-associated infections. The most common are infections of the urinary tract5, surgical6 site and bloodstream.
A medical worker prepares to visit patients with an antibiotic7-resistant infection at a retirement8 home in Oslo, Norway
FAITH LAPIDUS: Many infections have been increasing while hospitals are taking steps to improve. The report shows, for example, an eight percent increase in cases of sepsis, or bloodstream infection, following surgical operations.
About forty percent of all health care-associated infections are linked to the use of catheters. Catheters are placed inside the body to collect waste fluids, so the patient does not have to get out of bed. But the report says the devices should be used only when necessary. It says urinary tract infections increased more than three and a half percent after a surgical operation.
BOB DOUGHTY: Another way to prevent infections is to give patients antibiotic drugs before an operation. Doctors are advised to give the drugs within the hour before surgery. Patients who get them earlier than one hour are more likely to get an infected surgical wound.
Also, doctors are advised to discontinue antibiotics9 within twenty-four hours after the surgery. The report says longer than that is usually not necessary. It can increase the risk of antibiotic resistance and serious kinds of diarrhea.
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FAITH LAPIDUS: Asian monsoons11 affect half of the world’s population. Yet monsoons are difficult to predict. American researchers have put together a seven hundred-year record of the rainy seasons. The researchers say the record is expected to provide guidance to experts making weather predictions.
Every year, moist air masses known as monsoon10 produce large amounts of rainfall in India, East Asia, northern Australia and East Africa. All this wet air is pulled in by a high pressure area over the Indian Ocean and a low pressure area to the south.
BOB DOUGHTY: Edward Cook works with the Lamont-Doherty Earth Observatory12 at Columbia University in New York. He says the complex nature of the climate systems across Asia makes monsoons hard to predict. Professor Cook says climate records for the area have been kept since nineteen fifty. He says they are too recent and not detailed13 enough to be of much use.
So he and a team of researchers spent more than fifteen years traveling across Asia. They looked for trees old enough to provide long-term records. They measured the rings, or circles, inside thousands of ancient trees in more than three hundred places.
FAITH LAPIDUS: Rainfall has a direct link to the growth and width of rings on some kinds of trees. The researchers developed a document they are calling a Monsoon Asia Drought Atlas14. It shows the effect of monsoons over seven centuries, beginning in the thirteen hundreds.
Professor Cook says the tree-ring records show periods of wet and dry weather.
EDWARD COOK: “If the monsoon basically fails or is a very weak one, the trees affected15 by monsoons at that location might put on a very narrow ring. But if the monsoon is very strong, the trees affected by that monsoon might put on a wide ring for that year. So, the wide and narrow ring widths of the chronology that we developed in Asia provide us with a measure of monsoon variability.”
FAITH LAPIDUS: With all this information, researchers say they can begin to improve computer climate models for predicting the behavior of monsoons.
Eugene Wahl is a scientist with America’s National Oceanic and Atmospheric16 Administration.
EUGENE WAHL: “There has been widespread famine and starvation and human dying in the past in large droughts. And on the other hand, if the monsoon is particularly heavy it can cause extensive flooding. So, to get a sense of what the regional moisture patterns have been, dryness and wetness over such a long period of time in great detail, I would call it a kind of victory for paleoclimate science.”
FAITH LAPIDUS: A report about the Monsoon Asia Drought Atlas appeared in Science magazine.
(MUSIC)
BOB DOUGHTY: Finally, is there life on Mars? Or Venus? Or on any of the other planets either inside or outside our solar system? That is one of the greatest mysteries that scientists are attempting to answer.
Steve Squyres is the chief scientist for the American space agency’s Mars Rover Project. He says the agency currently has twenty-eight projects working in astrobiology, or the study of life in outer space. One involves landing on the surface of the planet Mercury. Others go much deeper into space.
FAITH LAPIDUS: Steve Squyres says one of the most complex projects involves landing on Mars. A robot would then pick up rocks and soil, and send them back to earth for testing.
The scientist says this mission has been planned for many years, but he is not sure when it will happen. The huge costs of space flights often delay them for years. But as he says, the search for life in outer space is a long-term goal, and he is still hopeful.
Other projects include sending unmanned spacecraft to Europa, an icy moon of the planet Jupiter. Scientists would use radar17 to search for liquids under the ice. Life is thought to need both water and the right chemicals to guarantee survival.
But not all tests for life in outer space take place far away, and not all involve the search for liquids. University of California biologist Bill Schopf studies ancient fossils and the dirt they are found in on earth. He examined fossilized remains18 in a piece of gypsum found on the bottom of the Mediterranean19 Sea. So when spacecraft are sent to other planets, scientists will look for layers of gypsum in hopes of finding similar fossils. One such gypsum field was found on Mars six years ago.
Water and organic materials are necessary for life as we know it. Scientists strongly believe that finding such substances will be goals of future space flights. Getting them back to earth for study is the next big project.
(MUSIC)
BOB DOUGHTY: This SCIENCE IN THE NEWS was written by Jim Tedder20, Caty Weaver21 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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1
doughty
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| adj.勇猛的，坚强的 | |
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2
coastal
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| adj.海岸的，沿海的，沿岸的 | |
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outweigh
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| vt.比...更重，...更重要 | |
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4
collapse
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| vi.累倒；昏倒；倒塌；塌陷 | |
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tract
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| n.传单，小册子，大片(土地或森林) | |
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surgical
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| adj.外科的，外科医生的，手术上的 | |
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7
antibiotic
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| adj.抗菌的；n.抗生素 | |
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8
retirement
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| n.退休，退职 | |
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9
antibiotics
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| n.（用作复数）抗生素；（用作单数）抗生物质的研究；抗生素，抗菌素( antibiotic的名词复数 ) | |
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monsoon
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| n.季雨，季风，大雨 | |
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11
monsoons
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| n.（南亚、尤指印度洋的）季风( monsoon的名词复数 )；（与季风相伴的）雨季；（南亚地区的）雨季 | |
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12
observatory
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| n.天文台，气象台，瞭望台，观测台 | |
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13
detailed
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| adj.详细的，详尽的，极注意细节的，完全的 | |
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atlas
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| n.地图册，图表集 | |
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affected
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| adj.不自然的，假装的 | |
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atmospheric
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| adj.大气的，空气的；大气层的；大气所引起的 | |
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radar
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| n.雷达，无线电探测器 | |
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remains
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| n.剩余物，残留物；遗体，遗迹 | |
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Mediterranean
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| adj.地中海的；地中海沿岸的 | |
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tedder
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| n.（干草）翻晒者，翻晒机 | |
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weaver
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| n.织布工；编织者 | |
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