VOA慢速英语 2008 0415b

VOICE ONE:

This is SCIENCE IN THE NEWS in VOA Special English. I'm Bob Doughty¹.

VOICE TWO:

And I'm Faith Lapidus. This week, we will tell about a large piece of ice breaking away from Antarctica. We also tell about a study of human emotions and discovery of an ancient flying reptile². We also have new information about a product widely used to prevent insect bites.

(MUSIC)

VOICE ONE:
　

These satellite images show the Wilkins Ice Shelf as it began to break up. The large image is from March 6; the images at right, from top to bottom, are from February 28, February 29 and March 8.

Satellite images show that a large piece of Antarctica’s Wilkins Ice Shelf has collapsed³. Scientists are blaming rising temperatures for the break-up of the four hundred square-kilometer piece of ice.

The Wilkins Ice Shelf is an area of huge, thick ice on the southwest Antarctic Peninsula. It is about one thousand miles south of South America.

The satellite images came from America's National Snow and Ice Data Center at the University of Colorado. The images show the ice began moving away from the ice shelf on February twenty-eighth. After seeing the pictures, scientists flew over the area. They saw huge pieces of broken ice floating in all directions.

VOICE TWO:

A large part of the Wilkins Ice Shelf is now being supported by a thin piece of ice. Some scientists say the ice shelf could completely break up within a few years. However, it is expected to survive until next year because summer is now ending in Antarctica.

The Arctic Peninsula has experienced warming conditions over the past half century. Several ice shelves have collapsed during the past thirty years. Six of them have collapsed completely.

VOICE ONE:

Ice shelves float on seawater, but are connected to land. They are made of fresh water that once fell as snow.

Scientists believe the recent activity in the Wilkins Ice Shelf will not have an immediate⁴ effect. Since ice shelves are already floating, their break-up does not affect sea levels. But glaciers⁵ are different. They sit on land. Ice shelves are able to prevent some glaciers from sliding into the ocean. These glaciers can begin moving at a faster rate after ice shelves break apart.

If large amounts of ice slide into the sea at a high rate of speed, new mass is added to the ocean. This, scientists say, can raise the world’s sea levels. Rising sea levels can lead to coastal⁶ flooding. Some scientists have urged that more be done to limit the effects of human-caused climate change.

(MUSIC)

VOICE TWO:

A new study shows that unhappiness in middle age is a common experience.

Two economists⁷ carried out the study. They are Andrew Oswald of the University of Warwick in England and David Blanchflower at Dartmouth College in New Hampshire. They used information collected earlier on two million people from eighty nations. Their study is being reported this month in the publication Social Science and Medicine.

The economists found that people around the world seem to share an emotional design in life. That design, they say, is shaped like the letter U. Happiness levels are highest when people are young and when they are old. In the middle, however, most people's happiness and life satisfaction levels decrease.

VOICE ONE:

Professor Oswald says some people suffer from midlife depression more than others. But, he says, it happens to men and women, to single and married people, and to those with and without children. Generally, people reach their lowest levels between the ages of about forty and fifty-five. But then, as they become older, their happiness starts to climb back up.

What the research does not show is why all this happens. Professor Oswald says one possibility is that people recognize their limitations in middle age and give up on some long-held dreams.

Or perhaps people who are happier live longer, and this is responsible for a growing percentage of happy older people. Or, he says, maybe people have seen others their age die and they value more their own remaining years.

(MUSIC)

VOICE TWO:

Researchers have found remains⁸ of a small, flying reptile that existed about one hundred twenty million years ago. The researchers say it was about the size of a modern bird -- the sparrow.

The reptile was not fully⁹ developed when it died. But neither was it a newborn or just hatched from an egg. Scientists had not known about the ancient creature before its fossils were discovered in northeastern China.

Researchers from Brazil and China published their discovery in Proceedings¹⁰ of the National Academy of Sciences.

VOICE ONE:

The researchers named the reptile Nemicolopterus crypticus. The name describes a hidden flying creature that lived in forests. The researchers say its bone structure is almost complete. From wing to wing, the reptile measured only two hundred fifty millimeters. The wings were covered with skin instead of feathers.

Because the skeleton was almost complete, the researchers described it as one of the smallest lizards¹¹ with wings ever found.

The reptile looked like a flying mouse. But it shared a common ancestor with dinosaurs¹². The researchers say some foot bones make Nemicolopterus crypticus different from other reptiles¹³. They believe the shape of the bones shows it lived mainly in treetops. They say the creature had no teeth. But it could eat insects.

VOICE TWO:

Researcher Alexander Kellner works at the National Museum of Rio de Janeiro’s Federal University. He says the animal probably lived in what is now eastern China. The remains were found in a rocky inland area. The surroundings are rich in fossils of its kind. Others were found nearby.

Nemicolopterus crypticus belonged to the scientific group called Pterosaurs. The group's biggest member was called Quetzalcoatlus. From wing to wing, it measured eleven meters. That wingspan made it one of the biggest of animals that could fly. The Quetzalcoatlus were also the first animals with backbones¹⁴ to fly.

(MUSIC)

VOICE ONE:

Finally, we have new findings about an old method for keeping away insects. Scientists have uncovered the molecular¹⁵ workings of DEET, the most widely used product for preventing insect bites. The scientists say their findings could lead to improved products that are safe enough for children to use.

Fifty years ago, the United States Army and Department of Agriculture developed DEET to protect soldiers from disease-carrying insects. Since then, it has been used to guard against blood-sucking insects, like mosquitoes carrying malaria¹⁶. DEET has been shown to work on almost all insects, including ticks, which spread Lyme disease.

VOICE TWO:

Until recently, no one had explained exactly how the product keeps insects away from skin. Some people thought that because DEET’s strong smell is not pleasing to human beings, it also smelled bad to insects. But the new study shows that DEET temporarily interferes¹⁷ with an insect’s ability to smell.

Leslie Vosshall is a professor of neurogenetics at Rockefeller University in New York. She was the lead investigator¹⁸ of the study.

Her team carried out experiments with mosquitoes and fruit flies. She says they discovered proteins in the antennae¹⁹ of both insects that identify several smells. The antennae help the insects identify smells, including those of human breath and sweat. As a result, the insects are able to identify human beings as food.

VOICE ONE:

Professor Vosshall says DEET works by stopping some of the smell proteins, or receptors, in the antennae. When insects come in contact with DEET, they are no longer able to guide themselves to their target. She says the insects do not bite people wearing DEET because they cannot smell them. Other studies have suggested that DEET affects the smelling abilities of insects. But the new study is the first to identify DEET’s molecular targets.

DEET is widely used and found in more than one hundred products. It is not considered dangerous when placed on clothing and unprotected arms and legs. But DEET is not advised for young children, especially those under two months old. Concerns about possible health risks have led scientists to work on improvements.

Professor Vosshall says the new information about DEET could help in the development of other, safer products. She says such products could even be used on babies.

(MUSIC)

VOICE TWO:

This SCIENCE IN THE NEWS was written by Brianna Blake, Jerilyn Watson and Caty Weaver²⁰. Brianna Blake was also our producer. I'm Faith Lapidus.

VOICE ONE:

And I'm Bob Doughty. 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 reptile   

n.爬行动物；两栖动物

参考例句：

• The frog is not a true reptile.青蛙并非真正的爬行动物。
• So you should not be surprised to see someone keep a reptile as a pet.所以，你不必惊奇有人养了一只爬行动物作为宠物。

3 collapsed   

adj.倒塌的

参考例句：

• Jack collapsed in agony on the floor. 杰克十分痛苦地瘫倒在地板上。
• The roof collapsed under the weight of snow. 房顶在雪的重压下突然坍塌下来。

4 immediate   

adj.立即的；直接的，最接近的；紧靠的

参考例句：

• His immediate neighbours felt it their duty to call.他的近邻认为他们有责任去拜访。
• We declared ourselves for the immediate convocation of the meeting.我们主张立即召开这个会议。

5 glaciers   

冰河，冰川( glacier的名词复数 )

参考例句：

• Glaciers gouged out valleys from the hills. 冰川把丘陵地带冲出一条条山谷。
• It has ice and snow glaciers, rainforests and beautiful mountains. 既有冰川，又有雨林和秀丽的山峰。 来自英语晨读30分（高一）

6 coastal   

adj.海岸的，沿海的，沿岸的

参考例句：

• The ocean waves are slowly eating away the coastal rocks.大海的波浪慢慢地侵蚀着岸边的岩石。
• This country will fortify the coastal areas.该国将加强沿海地区的防御。

7 economists   

n.经济学家，经济专家( economist的名词复数 )

参考例句：

• The sudden rise in share prices has confounded economists. 股价的突然上涨使经济学家大惑不解。
• Foreign bankers and economists cautiously welcomed the minister's initiative. 外国银行家和经济学家对部长的倡议反应谨慎。 来自《简明英汉词典》

8 remains   

n.剩余物，残留物；遗体，遗迹

参考例句：

• He ate the remains of food hungrily.他狼吞虎咽地吃剩余的食物。
• The remains of the meal were fed to the dog.残羹剩饭喂狗了。

9 fully   

adv.完全地，全部地，彻底地；充分地

参考例句：

• The doctor asked me to breathe in,then to breathe out fully.医生让我先吸气，然后全部呼出。
• They soon became fully integrated into the local community.他们很快就完全融入了当地人的圈子。

10 proceedings   

n.进程，过程，议程；诉讼(程序)；公报

参考例句：

• He was released on bail pending committal proceedings. 他交保获释正在候审。
• to initiate legal proceedings against sb 对某人提起诉讼

11 lizards   

n.蜥蜴( lizard的名词复数 )

参考例句：

• Nothing lives in Pompeii except crickets and beetles and lizards. 在庞培城里除了蟋蟀、甲壳虫和蜥蜴外，没有别的生物。 来自辞典例句
• Can lizards reproduce their tails? 蜥蜴的尾巴断了以后能再生吗？ 来自辞典例句

12 dinosaurs   

n.恐龙( dinosaur的名词复数 )；守旧落伍的人，过时落后的东西

参考例句：

• The brontosaurus was one of the largest of all dinosaurs. 雷龙是所有恐龙中最大的一种。 来自《简明英汉词典》
• Dinosaurs have been extinct for millions of years. 恐龙绝种已有几百万年了。 来自《简明英汉词典》

13 reptiles   

n.爬行动物，爬虫( reptile的名词复数 )

参考例句：

• Snakes and crocodiles are both reptiles. 蛇和鳄鱼都是爬行动物。 来自《简明英汉词典》
• Birds, reptiles and insects come from eggs. 鸟类、爬虫及昆虫是卵生的。 来自《现代汉英综合大词典》

14 backbones   

n.骨干( backbone的名词复数 )；脊骨；骨气；脊骨状物

参考例句：

• Why do hummingbirds and gorillas both have backbones? 为什么蜂鸟和大猩猩都有脊骨？ 来自辞典例句
• Simply adding bandwidth to the Internet backbones is not an answer. 只是简单的在互联网骨架上增加带宽是应付不了的。 来自互联网

15 molecular   

adj.分子的；克分子的

参考例句：

• The research will provide direct insight into molecular mechanisms.这项研究将使人能够直接地了解分子的机理。
• For the pressure to become zero, molecular bombardment must cease.当压强趋近于零时，分子的碰撞就停止了。

16 malaria   

n.疟疾

参考例句：

• He had frequent attacks of malaria.他常患疟疾。
• Malaria is a kind of serious malady.疟疾是一种严重的疾病。

17 interferes   

vi. 妨碍，冲突，干涉

参考例句：

• The noise interferes with my work. 这噪音妨碍我的工作。
• That interferes with my plan. 那干扰了我的计划。

18 investigator   

n.研究者，调查者，审查者

参考例句：

• He was a special investigator for the FBI.他是联邦调查局的特别调查员。
• The investigator was able to deduce the crime and find the criminal.调查者能够推出犯罪过程并锁定罪犯。

19 antennae   

n.天线；触角

参考例句：

• Sometimes a creature uses a pair of antennae to swim.有时某些动物使用其一对触须来游泳。
• Cuba's government said that Cubans found watching American television on clandestine antennae would face three years in jail.古巴政府说那些用秘密天线收看美国电视的古巴人将面临三年监禁。

20 weaver   

n.织布工；编织者

参考例句：

• She was a fast weaver and the cloth was very good.她织布织得很快，而且布的质量很好。
• The eager weaver did not notice my confusion.热心的纺织工人没有注意到我的狼狈相。