VOA慢速英语2009-SCIENCE IN THE NEWS - Ancient Footprints Let Exp

VOICE ONE:

This is SCIENCE IN THE NEWS in VOA Special English. I'm Barbara Klein.

VOICE TWO:

And I'm Bob Doughty¹. This week, we will tell about evidence of early human ancestors. We also will tell about the health effects of hopeful feelings. And, we will tell about disappearing bat populations in the northeastern United States.

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VOICE ONE:
　
Christine Galvagna, part of a Rutgers team, cleans a trail of hominid footprints

An international research team has discovered markings made by the ancestors of modern human beings more than one million years ago. The discovery is exciting because it shows the shape of the feet and walking method of the human ancestors.

Rutgers University Professor Jack² Harris led the researchers and students who uncovered the marks during three years of digging. They found the ancient footprints near the village of Ileret in northern Kenya. A report about their findings was published last month in Science magazine.

VOICE TWO:

Early humans made the footprints as they walked on volcanic³ ash and soil that turned to rock over time. The team found two sets of prints in separate levels of rock that are about one million five hundred thousand years old.

The scientists say the prints were left by one of two human ancestors: either Homo erectus or Homo ergaster. However, many experts do not recognize a difference between the two. Homo erectus is the more commonly used name.

VOICE ONE:

Surprisingly, the footprints look much like those you would find on a sandy coastline today. In their report, the team said the discovery provides the oldest evidence of a foot structure that is generally the same as a modern human's.

The prints show how the big toe of Homo erectus is close to the other toes. In earlier species, the big toe is separated widely from the other toes -- as in the foot structure of apes. No Homo erectus foot bones have ever been found. This makes the well-preserved footprints especially valuable.

VOICE TWO:

Scientists have also learned how Homo erectus walked from the prints. Researcher Matthew Bennett of Bournemouth University used laser technology to make digital images of the footprints. These images suggest that Homo erectus walked by touching⁴ the ground first with the back of the foot and pushing off with the front -- just as we do.

The researchers could even estimate the height of the ancient individuals. One was only about a meter tall. It is believed to have been a child. The others were about the average height of modern human adults.

VOICE ONE:

The findings provide more evidence that human ancestors were able to travel long distances. Homo erectus may have left Africa for other parts of the world as early as one million eight hundred years ago.

This is only the second time that early human footprints have been found. In nineteen seventy eight, British anthropologist⁵ Mary Leaky discovered the prints of a possible human ancestor at Laetoli, Tanzania. They belonged to Australopithicus afarensis, a much earlier and smaller human-like creature that walked on two feet.

VOICE TWO:

Professor Harris says his team not only found footprints, but also many animal tracks in the rock. These include markings of hoofed⁶ animals that Homo erectus may have hunted for food. Other tracks belonged to meat-eaters. Such creatures were competitors or even threats to the early humans.

The footprints found in Kenya have let scientists step back in time to find new details about our distant ancestors and their environment.

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VOICE ONE:

An American study has shown that being hopeful about future events might help you stay healthy and live longer. The study found links between people's beliefs and their risks of cancer-related death, heart disease and early death.

Researchers studied one hundred thousand women during an eight-year period, beginning in nineteen ninety-four. All of the women were fifty years of age or older. The study was part of the Women's Health Initiative, a continuing study organized by the National Institutes of Health. The findings were presented earlier this month at a meeting of the American Psychosomatic Society.

VOICE TWO:

For the study, the women were asked questions that measured their beliefs or ideas about the future. The researchers attempted to identify each woman's personality eight years after gathering⁷ the information.

The study found that the hopeful individuals were fourteen percent less likely than other women to have died from any cause. The hopeful women were also thirty percent less likely to have died from heart disease after the eight years.

VOICE ONE:

Hilary Trindle was the lead writer of the report. She is an assistant professor of medicine at the University of Pittsburgh in Pennsylvania. She says the study confirms earlier research that also linked optimistic feelings to longer life. However, this study is different from earlier research on the subject.

The researchers also gathered information about people's education, financial earnings⁸, physical activity and use of alcoholic⁹ drinks or cigarettes. Independent of those things, the findings still showed that optimists¹⁰ had less of a chance of dying during the eight-year period.

VOICE TWO:

Some women who answered the study's questions were found to be cynically¹¹ hostile, or highly untrusting of others. These women were sixteen percent more likely to die than the others. They also were twenty-three percent more likely to die of cancer.

The study also found that women who were not optimistic were more likely to smoke, have high blood pressure or diabetes¹². They were also more likely not to exercise.

Professor Tindle says the study did not confirm whether optimism leads to healthier choices, or if it actually affected¹³ a person's physical health. She says the study does not prove that negative emotions or distrust lead to bad health effects, and shorter life. Yet there does appear to be a link between the two. More research is needed to discover the exact reasons for the findings.

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VOICE ONE:

In recent years, biologists have observed a sharp drop in bat populations in the northeastern United States. The biologists believe the drop has resulted from a mysterious sickness called white nose syndrome¹⁴.
　
A dead Indiana bat found in Rosendale, New York, earlier this year. White nose syndrome is killing¹⁵ more bats over a larger area of the U.S. this year.

Little is known about the sickness. It is called white nose syndrome because of a white-colored fungus¹⁶ found on the faces of affected bats. The fungus seems to grow in cold weather. The affected animals were first observed in two thousand seven in New York State.

Scientists believe the disease causes bats to awaken¹⁷ early from their hibernation¹⁸ or yearly rest period. The scientists say the bats then leave their resting places in search of food during the winter when the insects they eat are not available. Without a food supply, the bats starve to death.

VOICE TWO:

Wildlife officials say white nose syndrome is not a direct threat to other animals or human beings. However, the bats' continuing disappearance¹⁹ could have a far-reaching effect on the environment.

Bats have survived for about fifty million years. They eat large amounts of insects, up to twenty-five percent of their body weight in one night's feeding. If fewer bats are available to eat the insects, farmers will have to use more insect-killing chemical products to protect their crops. Diseases that are spread by insects could also become more common.

VOICE ONE:

Cases of white nose syndrome have been confirmed in New York, New Jersey²⁰, Connecticut, Vermont, Massachusetts and Pennsylvania. It is difficult for scientists to know the exact number of bats that have died as a result of white nose syndrome. However, some estimate that hundreds of thousands of bats have already disappeared.

The United States Geological Survey says the disease has affected six bat species. They include little brown bats, northern bats, tricolored bats, Indiana bats, small-footed myotis and big brown bats.

Biologists are currently studying possible ways to keep the disease from spreading. Tests are needed to guarantee a plan that will be effective.

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VOICE TWO:

This SCIENCE IN THE NEWS program was written by Mario Ritter and Brianna Blake, who was also our producer. I'm Bob Doughty.

VOICE ONE:

And I'm Barbara Klein. 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.

1 doughty   

adj.勇猛的，坚强的

参考例句：

• Most of successful men have the characteristics of contumacy and doughty.绝大多数成功人士都有共同的特质：脾气倔强，性格刚强。
• The doughty old man battled his illness with fierce determination.坚强的老人用巨大毅力与疾病作斗争。

2 jack   

n.插座，千斤顶，男人；v.抬起，提醒，扛举；n.（Jake）杰克

参考例句：

• I am looking for the headphone jack.我正在找寻头戴式耳机插孔。
• He lifted the car with a jack to change the flat tyre.他用千斤顶把车顶起来换下瘪轮胎。

3 volcanic   

adj.火山的；象火山的；由火山引起的

参考例句：

• There have been several volcanic eruptions this year.今年火山爆发了好几次。
• Volcanic activity has created thermal springs and boiling mud pools.火山活动产生了温泉和沸腾的泥浆池。

4 touching   

adj.动人的，使人感伤的

参考例句：

• It was a touching sight.这是一幅动人的景象。
• His letter was touching.他的信很感人。

5 anthropologist   

n.人类学家，人类学者

参考例句：

• The lecturer is an anthropologist.这位讲师是人类学家。
• The anthropologist unearthed the skull of an ancient human at the site.人类学家在这个遗址挖掘出那块古人类的颅骨。

6 hoofed   

adj.有蹄的，蹄形状的，装蹄的v.（兽的）蹄，马蹄( hoof的过去式和过去分词 )

参考例句：

• He was hoofed out of the Guards. 他被开除出警卫队。 来自互联网
• He hoofed his way to town. 他步行去了城里。 来自互联网

7 gathering   

n.集会，聚会，聚集

参考例句：

• He called on Mr. White to speak at the gathering.他请怀特先生在集会上讲话。
• He is on the wing gathering material for his novels.他正忙于为他的小说收集资料。

8 earnings   

n.工资收人；利润，利益，所得

参考例句：

• That old man lives on the earnings of his daughter.那个老人靠他女儿的收入维持生活。
• Last year there was a 20% decrease in his earnings.去年他的收入减少了20%。

9 alcoholic   

adj.（含）酒精的，由酒精引起的；n.酗酒者

参考例句：

• The alcoholic strength of brandy far exceeds that of wine.白兰地的酒精浓度远远超过葡萄酒。
• Alcoholic drinks act as a poison to a child.酒精饮料对小孩犹如毒药。

10 optimists   

n.乐观主义者( optimist的名词复数 )

参考例句：

• Even optimists admit the outlook to be poor. 甚至乐观的人都认为前景不好。 来自《简明英汉词典》
• Optimists reckon house prices will move up with inflation this year. 乐观人士认为今年的房价将会随通货膨胀而上涨。 来自辞典例句

11 cynically   

adv.爱嘲笑地，冷笑地

参考例句：

• "Holding down the receiver,'said Daisy cynically. “挂上话筒在讲。”黛西冷嘲热讽地说。 来自英汉文学 - 盖茨比
• The Democrats sensibly (if cynically) set about closing the God gap. 民主党在明智（有些讽刺）的减少宗教引起的问题。 来自互联网

12 diabetes   

n.糖尿病

参考例句：

• In case of diabetes, physicians advise against the use of sugar.对于糖尿病患者，医生告诫他们不要吃糖。
• Diabetes is caused by a fault in the insulin production of the body.糖尿病是由体內胰岛素分泌失调引起的。

13 affected   

adj.不自然的，假装的

参考例句：

• She showed an affected interest in our subject.她假装对我们的课题感到兴趣。
• His manners are affected.他的态度不自然。

14 syndrome   

n.综合病症；并存特性

参考例句：

• The Institute says that an unidentified virus is to blame for the syndrome. 该研究所表示,引起这种综合症的是一种尚未确认的病毒。
• Results indicated that 11 fetuses had Down syndrome. 结果表明有11个胎儿患有唐氏综合征。

15 killing   

n.巨额利润；突然赚大钱，发大财

参考例句：

• Investors are set to make a killing from the sell-off.投资者准备清仓以便大赚一笔。
• Last week my brother made a killing on Wall Street.上个周我兄弟在华尔街赚了一大笔。

16 fungus   

n.真菌，真菌类植物

参考例句：

• Mushrooms are a type of fungus.蘑菇是一种真菌。
• This fungus can just be detected by the unaided eye.这种真菌只用肉眼就能检查出。

17 awaken   

vi.醒，觉醒；vt.唤醒，使觉醒，唤起，激起

参考例句：

• Old people awaken early in the morning.老年人早晨醒得早。
• Please awaken me at six.请于六点叫醒我。

18 hibernation   

n.冬眠

参考例句：

• Bears wake up in the spring after a winter of hibernation.熊经过一个冬天的冬眠后在春季苏醒。
• The tortoise spends the winter months in hibernation.乌龟在冬眠中度过寒冬季节。

19 disappearance   

n.消失，消散，失踪

参考例句：

• He was hard put to it to explain her disappearance.他难以说明她为什么不见了。
• Her disappearance gave rise to the wildest rumours.她失踪一事引起了各种流言蜚语。

20 jersey   

n.运动衫

参考例句：

• He wears a cotton jersey when he plays football.他穿运动衫踢足球。
• They were dressed alike in blue jersey and knickers.他们穿着一致，都是蓝色的运动衫和灯笼短裤。