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This is Sarah Long.
And this is Bob Doughty with Science in the News, a VOA Special English program about recent developments in science.  Today, we tell about the oldest city in the Americas. We tell about an (1)ancestor of a famous (2)dinosaur.  We tell about how the American space agency is helping coffee growers. And we tell about how drinking alcohol can help your heart. 
Scientists working in Peru's Supe Valley have identified what they say are ruins of the oldest city ever found in the Americas.  They say the ruins include six huge stone (3) structures that look like hills.  The scientists say the (4) mounds were built by people who lived more than 4,000 years ago. That would make the mounds as old as the great (5) pyramids of Egypt. 
 The (6) archeologists say the mounds are the oldest known man-made structures in North America, Central America or South America.  Archeologists from the Field Museum in Chicago, Illinois, and Northern Illinois University announced the discovery. 
The mounds are in Caral, 200 kilometers north of Lima, Peru.  Scientists first discovered the ruins in Nineteen-Oh-Five.  However, archeologists had not done much work there.  The area has no modern roads, electric power or clean drinking water.  Also, scientists have never found (7) ceramic containers in the area because the people who lived there did not make stoneware.  So archeologists had not been very interested in the area until now. 
The scientists used (8) radiocarbon dating tests to (9) identify the age of the structures.  The method shows the level of a radioactive form of carbon in a substance.  The scientists tested the remains of plants used to make woven bags. They say the bags were important in building the mounds.  Workers filled the bags with rocks. Then they carried the bags to where the mounds were being built.  They placed the bags of rocks in the walls of the mounds. The tests showed the mounds were built as early as four- thousand, six- hundred years ago. 
The largest mound is eighteen meters high and one- hundred fifty meters wide.  The scientists say the six mounds and other structures were built around a huge public area. They say the mounds were probably used for (10) ceremonies and the administration of the city.  Steps and rooms were built on the top and sides of the mounds.  Scientists also found the ruins of small homes and larger buildings under sand and broken rock. 
Until now, experts had believed that the first (11) settlements in the Americas were coastal fishing villages.  Caral, however, is about twenty kilometers from the Pacific Ocean.  The scientists say the economy of Caral was based on agriculture.  They discovered evidence of simple (12) irrigation systems to water crops. These may have been the first irrigation systems in the Americas. 
Jonathan Haas of the Field Museum was one of the researchers. Mister Haas says Caral was a complex and well-developed society. He says the leaders of the ancient city were powerful people. They probably forced citizens to provide labor for building projects. 
Other scientists dispute the idea.  But they do agree on the importance of the ruins.  Experts say Caral was important in the social, political and economic development of (13) civilization in South America. 
Scientists have identified bones of a dinosaur found on the Isle of Wight, near the coast of England.  They believe the dinosaur is an ancestor of the fierce (14) Tyrannosaurus Rex.  But it is about two times older than the T-Rex. Experts say it is a new kind of dinosaur never(15)discovered before.  They say it is one of the most important discoveries of its kind ever made in Britain. 
A young collector found part of the foot of the dinosaur in Nineteen-Ninety-Seven.  Gavin Leng discovered this sharp, pointed claw on a high point of land near Newport.  He took it to the Isle of Wight Museum of (16) Geology.
Experts dug in the area where the claw was found.  They unearthed about forty percent of the dinosaur. The experts call it Eotyrannus Lengi, in honor of the man who discovered it.  They say it is one of the most (17)complete and important dinosaurs of this age ever found. It provides a lot of new information about early tyrannosaurs. 
Scientists believe Eotyrannus Lengi lived about one- hundred- twenty- five- million years ago.  It was about four meters long.  Its large head was filled with sharp teeth.  Its head and shoulder were similar to tyrannosaurs that lived later. But those dinosaurs were much larger.  They lived about sixty- million years ago. Scientists have found evidence of about twenty kinds of dinosaurs on the Isle of Wight. 
The American space agency is making plans to help coffee growers in the state of Hawaii.  NASA will send an aircraft high above fields where coffee plants are grown.  The aircraft will gather color images of the plants during the harvest season.  From this information, the (18) Hawaiian coffee growers will know exactly when to harvest their crops.
NASA will use a special aircraft that flies without a pilot.  Officials say the project will show that the aircraft can carry scientific observation equipment on long flights.  They say it can fly higher than a traditional aircraft with a pilot. 
The aircraft is called Pathfinder-Plus.  It is powered by energy from the sun.The aircraft will fly over the largest coffee farm in the United States, the Kauai Coffee Company plantation.  Researchers hope (19) Pathfinder-Plus will gather information the growers can use to select the best time to harvest the coffee beans.
Two new studies have added to the evidence that drinking a little alcohol each day is good for the heart.  Earlier studies have shown that drinking a moderate amount of alcohol reduces the chances of suffering a heart attack or a stroke caused by thickening of the blood.
The new studies were published in the Journal of the American Medical Association. One group of researchers was from Beth Israel Deaconess Medical Center in Boston, Massachusetts.  They questioned almost two- thousand patients at forty-five hospitals.  All the patients had just suffered heart attacks. 
The researchers asked them how much alcohol they drank in the year before the heart attack.  Those who had fewer than seven alcoholic drinks a week were considered light drinkers.  Those who had more than seven drinks a week were considered (20) moderate drinkers.
The researchers studied the patients' health for the next four years.  At the end of that time, the light drinkers had a twenty-one percent lower chance of dying from a heart attack than those who never drank at all.  The moderate drinkers had a thirty-two percent lower chance of dying than those who never drank.  The drinkers survived mostly because they had fewer additional heart attacks.
The other study involved more than two- thousand older men and women.  Their average age was seventy-four. Researchers from Emory University in Atlanta, Georgia asked them how much alcohol they drank.  The researchers studied the health of these people for up to fourteen years.  They found that those who had one or two drinks each day were twenty to fifty percent less likely to develop heart failure than those who did not drink. The studies found no difference in survival among people who drank beer, wine or liquor. 
Arthur Klatsky is a heart doctor at the Kaiser Permanente Medical Center in Oakland, California. Doctor Klatsky said both studies strengthen the idea that drinking a small amount of alcohol each day can protect the heart.  Alcohol thins the blood and prevents clots that block (21) arteries. It also increases the so-called good (22) cholesterol in the blood that helps keep arteries open. However, other health risks have been linked to moderate drinking.  And Doctor Klatsky said heavy alcohol drinking is a sure way to damage your health.
This SCIENCE IN THE NEWS program was written by George Grow, Jerilyn Watson and Nancy Steinbach. It was produced by Nancy Steinbach.  This is Sarah Long.
And this is Bob Doughty.  Join us again next week for more news about science in Special English on the Voice of America.

(1) ancestor[ 5AnsistE ]n.祖先, 祖宗
(2) dinosaur[ 5dainEsC: ]n.恐龙
(3) structure[ 5strQktFE ]n.结构, 构造, 建筑物v.建筑, 构成
(4) mound[ maund ]n.土墩, 护堤
(5) pyramid[ 5pirEmid ]n.角锥,金字塔
(6) archeologist[9B:kI`ClEdVIst]n.考古学家
(7) ceramic[ si5rAmik ]adj.陶器的n.陶瓷制品
(8) radiocarbon[ 5reidiEu5kB:bEn ]n.放射性碳, 碳的放射性同位元素
(9) identify[ ai5dentifai ]v.识别, 鉴别
(10) ceremony[ 5serimEni ]n.典礼, 仪式
(11) settlement[ 5setlmEnt ]n.沉降, 解决
(12) irrigation[ 7iri5^eiFEn ]n.灌溉, 冲洗
(13) civilization[9sIvIlaI`zeIFLn;-lI`z-]n.文明, 文化
(14) tyrannosaurus[tIrAnE5sC:rEs]n.暴龙
(15) discover[ dis5kQvE ]v.发现, 发觉
(16) geology[ dVi5ClEdVi ]n.地质学, 地质概况
(17) complete[ kEm5pli:t ]adj.全部的, 完全的, 完成的v.完成, 使完善
(18) Hawaiian[ hB:5waiiEn ]n.夏威夷人, 夏威夷语adj.夏威夷的, 夏威夷语的
(19) pathfinder[5pB:WfaIndE(r)]n.探险者, 开创者
(20) moderate[ 5mCdErit ]adj.中等的, 适度的, 适中的v.缓和
(21) artery[ 5B:tEri ]n.动脉, 要道
(22) cholesterol[ kE5lestErEul, -rCl ]n.胆固醇