VOA慢速英语2010年-SCIENCE IN THE NEWS - Locusts

BOB DOUGHTY¹: This is SCIENCE IN THE NEWS in VOA Special English. I’m Bob Doughty.

KATHERINE COLE: And I’m Katherine Cole. Today, we will tell how some insects might prove useful against hard-to-fight diseases. We will tell about a program to protect crops from harmful insects. We also will examine a possible effect of volcanic² activity long ago. And we will describe an unusual recycling program.

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BOB DOUGHTY: People have feared locusts⁴ for thousands of years. The insects can destroy whole fields of crops. And very few people like cockroaches⁶. They eat waste. They spread their own waste and carry disease germs that threaten human health.

But, wait, there may be something good about locusts and cockroaches. At least, scientists in England think so. They performed research that may help make possible new medicines to fight bacterial⁷ diseases that resist current drugs.

KATHERINE COLE: Simon Lee led a team of experts from the University of Nottingham. His team found that locusts and cockroaches carry substances that may help kill microbes. Mr. Lee is a graduate student in the School of Veterinary Medicine and Science at Nottingham University. He presented the findings at a meeting of the Society for General Microbiology.

Locusts

In experiments, the scientists combined substances from the American cockroach⁵ and the desert locust³. They examined this material against disease-causing bacteria. E. coli is often an innocent bacterium⁸. But the E. coli used in this study was responsible for the disease meningitis. The team also tested the insect material on methicillin-resistant staphylococcus aureus, also known as the disease MRSA.

BOB DOUGHTY: The scientists crushed the brains of the insects and combined them. They placed the combined material with the bacteria. The material and the bacteria were kept warm in an incubator for two hours. Next, the scientists put the material into special containers. The test material was left in culture dishes overnight.

Mr. Lee tested nerve tissue from the thorax of the desert locust separately. The thorax is a body part between the throat and the abdomen⁹.

At the end of the experiments, ninety percent of the bacteria were dead. The scientists say they recognized up to nine molecules¹⁰ in the tissues that appeared to have killed the bacteria. Researchers have begun to test the molecules against other infections that are difficult to treat.

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A cloud of locusts in Cancun, Mexico, in 2006

KATHERINE COLE: Farmers know that if you reduce harmful insects and diseases in your crops, you have a chance for a better harvest. Today, many farmers and experts praise integrated pest management, or IPM. IPM is a series of choices and methods to control insects, diseases and fungi¹¹.

The program provides current information on how pests live and act in the environment. A number of nongovernmental and other organizations in many countries provide education in IPM.

James Frederick works for Clemson University’s Pee Dee Research and Educational Center in South Carolina. He says one IPM method is to plant as early in the season as possible so that most of the crop will be in by the time a disease or pest arrives. Not all insects are pests. Some are helpful. IPM programs help farmers learn to identify different kinds.

BOB DOUGHTY: Another IPM method is rotating crops. Farmers do not plant the same crop season after season in the same soil. Instead, they may plant corn one season, soybeans the next, then corn again.

Professor Frederick says farmers need information about what crops are best to plant. He says that sometimes disease-resistant crops will reduce harvests. He said a last choice would be chemical control. But he suggests using management methods first.

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KATHERINE COLE: Scientists in Russia are suggesting that climate change after volcanic activity caused Neanderthals to disappear from earth. The suggestion appeared recently in the publication Current Anthropology¹². The Neanderthals were early relatives of human beings. They lived in Europe until about forty thousand years ago.

Scientists from the ANO Laboratory of Prehistory in Saint Petersburg did the research. They proposed that huge volcanic explosions caused the Neanderthals to die out in Western Europe. As evidence, they point to the Caucasus Mountains of southern Russia.

BOB DOUGHTY: The scientists noted¹³ discoveries made in the Mezmaiskaya Cave, a hollow area in one of the mountains. Many Neanderthal bones and objects have been found there over time. The scientists studied two separate geological layers in the cave. They believe these layers of material were from the same time as major volcanic events. That was about forty thousand to forty-five thousand years ago.

The scientists say some ash in the cave formed after a volcano exploded in what is now Italy. Another ash layer formed around the same time as a smaller volcanic explosion that is thought to have taken place in the Caucasus.

KATHERINE COLE: The scientists say the geological layers show evidence of sudden climate change. They say the layers show reduced pollen¹⁴ compared to surrounding layers.

The scientists say the reduction means a change to a dryer¹⁵ and cooler climate. They propose that the explosions caused what is known as a volcanic winter. Such an event takes place when clouds of ash block sunshine for long periods, causing loss of warmth.

The change may have destroyed the local environment. The area for hunting animals became severely¹⁶ limited. Animal bones disappeared from the cave about forty-five thousand years ago.

BOB DOUGHTY: The research team proposes that loss of Neanderthal life helped human beings spread out their living area.

Early modern people were in more southern and western parts of Eurasia when the volcanoes erupted. But they escaped direct effect. About two thousand years passed. Then the humans moved north. The researchers say they were able to occupy the area that once was home to Neanderthals.

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KATHERINE COLE: Finally, recycling programs usually give new life to materials like paper, metal, plastic and glass. But a program in the eastern United States is recycling shellfish to help the Chesapeake Bay.

Oysters¹⁸ are filter feeders. That means they help clean the water. At the same time, generation upon generation of oysters form reefs. These structures provide homes for fish and crabs¹⁹. Oysters are a Chesapeake tradition. And they are good for the bay. But environmental damage and too much harvesting have cut the oyster¹⁷ population of the Chesapeake.

As part of Maryland's oyster recovery program, children learn that marine²⁰ life needs to be protected

BOB DOUGHTY: An organization called the Oyster Recovery Partnership²¹ started the recycling program earlier this year. Baby oysters need to attach themselves to a shell or other hard surface as they grow. Scientists are using recycled shells as part of an oyster reproduction program.

More than fifty restaurants, seafood²² dealers²³ and other businesses have joined the Oyster Shell Recycling Alliance. Two states, Maryland and Virginia, are also taking part in the program.

KATHERINE COLE: The Oyster Recovery Partnership takes away oyster shells for recycling. First the shells get washed. Then they go to the Center for Environmental Science at the University of Maryland for further processing.

The shells are placed in containers with hundreds of millions of oyster larvae²⁴. This way, the baby oysters can be raised until they have grown big enough to be moved to the Chesapeake.

BOB DOUGHTY: This year, the Oyster Recovery Partnership helped produce and plant more than four hundred fifty million baby oysters in the bay. Don Meritt heads the oyster recovery program at the University of Maryland. He says the goal is not just to increase the oyster population.

DON MERITT: “Our real goal here is to try to bring healthy oyster populations back to the Chesapeake Bay so that we can help restore a healthy Chesapeake Bay. Not just a healthy oyster population, but a healthy bay."

BOB DOUGHTY: Mr. Meritt says it will take many years of work before the Chesapeake Bay has a good supply of oysters again.

(MUSIC)

KATHERINE COLE: This SCIENCE IN THE NEWS was written by Jerilyn Watson. June Simms was our producer. I’m Katherine Cole.

BOB DOUGHTY: And I’m Bob Doughty. You can find transcripts²⁵, MP3s and podcasts of 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 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。

3 locust   

n.蝗虫；洋槐，刺槐

参考例句：

• A locust is a kind of destructive insect.蝗虫是一种害虫。
• This illustration shows a vertical section through the locust.本图所示为蝗虫的纵剖面。

4 locusts   

n.蝗虫( locust的名词复数 )；贪吃的人；破坏者；槐树

参考例句：

• a swarm of locusts 一大群蝗虫
• In no time the locusts came down and started eating everything. 很快蝗虫就飞落下来开始吃东西，什么都吃。 来自《简明英汉词典》

5 cockroach   

n.蟑螂

参考例句：

• A cockroach can live several weeks with its head off.蟑螂在头被切掉后仍能活好几个星期。
• She screamed when she found a cockroach in her bed.她在床上找到一只蟑螂时大声尖叫。

6 cockroaches   

n.蟑螂( cockroach的名词复数 )

参考例句：

• At night, the cockroaches filled the house with their rustlings. 夜里，屋里尽是蟑螂窸窸瑟瑟的声音。 来自辞典例句
• It loves cockroaches, and can keep a house clear of these hated insects. 它们好食蟑螂，可以使住宅免除这些讨厌昆虫的骚扰。 来自百科语句

7 bacterial   

a.细菌的

参考例句：

• Bacterial reproduction is accelerated in weightless space. 在失重的空间，细菌繁殖加快了。
• Brain lesions can be caused by bacterial infections. 大脑损伤可能由细菌感染引起。

8 bacterium   

n.(pl.)bacteria 细菌

参考例句：

• The bacterium possibly goes in the human body by the mouth.细菌可能通过口进入人体。
• A bacterium is identified as the cause for his duodenal ulcer.一种细菌被断定为造成他十二指肠溃疡的根源。

9 abdomen   

n.腹，下腹(胸部到腿部的部分)

参考例句：

• How to know to there is ascarid inside abdomen?怎样知道肚子里面有蛔虫？
• He was anxious about an off-and-on pain the abdomen.他因时隐时现的腹痛而焦虑。

10 molecules   

分子( molecule的名词复数 )

参考例句：

• The structure of molecules can be seen under an electron microscope. 分子的结构可在电子显微镜下观察到。
• Inside the reactor the large molecules are cracked into smaller molecules. 在反应堆里，大分子裂变为小分子。

11 fungi   

n.真菌，霉菌

参考例句：

• Students practice to apply the study of genetics to multicellular plants and fungi.学生们练习把基因学应用到多细胞植物和真菌中。
• The lawn was covered with fungi.草地上到处都是蘑菇。

12 anthropology   

n.人类学

参考例句：

• I believe he has started reading up anthropology.我相信他已开始深入研究人类学。
• Social anthropology is centrally concerned with the diversity of culture.社会人类学主要关于文化多样性。

13 noted   

adj.著名的，知名的

参考例句：

• The local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
• Jim is noted for arriving late for work.吉姆上班迟到出了名。

14 pollen   

n.[植]花粉

参考例句：

• Hummingbirds have discovered that nectar and pollen are very nutritious.蜂鸟发现花蜜和花粉是很有营养的。
• He developed an allergy to pollen.他对花粉过敏。

15 dryer   

n.干衣机，干燥剂

参考例句：

• He bought a dryer yesterday.他昨天买了一台干燥机。
• There is a washer and a dryer in the basement.地下室里有洗衣机和烘干机。

16 severely   

adv.严格地；严厉地；非常恶劣地

参考例句：

• He was severely criticized and removed from his post.他受到了严厉的批评并且被撤了职。
• He is severely put down for his careless work.他因工作上的粗心大意而受到了严厉的批评。

17 oyster   

n.牡蛎；沉默寡言的人

参考例句：

• I enjoy eating oyster; it's really delicious.我喜欢吃牡蛎，它味道真美。
• I find I fairly like eating when he finally persuades me to taste the oyster.当他最后说服我尝尝牡蛎时，我发现我相当喜欢吃。

18 oysters   

牡蛎( oyster的名词复数 )

参考例句：

• We don't have oysters tonight, but the crayfish are very good. 我们今晚没有牡蛎供应。但小龙虾是非常好。
• She carried a piping hot grill of oysters and bacon. 她端出一盘滚烫的烤牡蛎和咸肉。

19 crabs   

n.蟹( crab的名词复数 )；阴虱寄生病；蟹肉v.捕蟹( crab的第三人称单数 )

参考例句：

• As we walked along the seashore we saw lots of tiny crabs. 我们在海岸上散步时看到很多小蟹。 来自《简明英汉词典》
• The fish and crabs scavenge for decaying tissue. 鱼和蟹搜寻腐烂的组织为食。 来自《简明英汉词典》

20 marine   

adj.海的；海生的；航海的；海事的；n.水兵

参考例句：

• Marine creatures are those which live in the sea. 海洋生物是生存在海里的生物。
• When the war broke out,he volunteered for the Marine Corps.战争爆发时，他自愿参加了海军陆战队。

21 partnership   

n.合作关系，伙伴关系

参考例句：

• The company has gone into partnership with Swiss Bank Corporation.这家公司已经和瑞士银行公司建立合作关系。
• Martin has taken him into general partnership in his company.马丁已让他成为公司的普通合伙人。

22 seafood   

n.海产食品，海味，海鲜

参考例句：

• There's an excellent seafood restaurant near here.离这儿不远有家非常不错的海鲜馆。
• Shrimps are a popular type of seafood.小虾是比较普遍的一种海味。

23 dealers   

n.商人( dealer的名词复数 )；贩毒者；毒品贩子；发牌者

参考例句：

• There was fast bidding between private collectors and dealers. 私人收藏家和交易商急速竞相喊价。
• The police were corrupt and were operating in collusion with the drug dealers. 警察腐败，与那伙毒品贩子内外勾结。

24 larvae   

n.幼虫

参考例句：

• Larvae are parasitic on sheep.幼虫寄生在绵羊的身上。
• The larvae prey upon small aphids.这种幼虫以小蚜虫为食。

25 transcripts   

n.抄本（ transcript的名词复数 ）；转写本；文字本；副本

参考例句：

• Like mRNA, both tRNA and rRNA are transcripts of chromosomal DNA. tRNA及rRNA同mRNA一样，都是染色体DNA的转录产物。 来自辞典例句
• You can't take the transfer students'exam without your transcripts. 没有成绩证明书，你就不能参加转学考试。 来自辞典例句