SCIENCE IN THE NEWS - As Butterflies Head South to Mexico, H

SCIENCE IN THE NEWS - As Butterflies Head South to Mexico, Humans Fly Along
By Caty Weaver¹, Jill Moss² and George Grow

Broadcast: Tuesday, October 04, 2005

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VOICE ONE:

This is SCIENCE IN THE NEWS in VOA Special English. I'm Doug Johnson.

VOICE TWO:

And I'm Faith Lapidus. On our program this week: new findings about the laboratory storage life of stem cells.

VOICE ONE:

 
 
Up close with monarch³ butterflies on their yearly migration⁴ in North America.

VOICE TWO:

And children are urged to get an early start on good heart health.

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VOICE ONE:

A new report says human embryonic⁶ stem cells kept for long periods of time develop changes in their genetic⁷ material. It says such changes may make the cells unusable for medical purposes.

Earlier studies had suggested that major genetic changes in stem cells were rare. But an international team of research scientists found this to be false. The publication Nature Genetics reported the findings.

The researchers used special tools to compare genetic changes in each of nine human embryonic stem cell lines. The stem cells were kept in a special liquid filled with nutrients⁸. The researchers found that the more the cells divided, the more likely they were to develop the changes, or mutations.

Some of these mutations are known to cause cells to become cancerous. However, stem cells that divided for only a short period of time were found to show no signs of mutation⁹.

VOICE TWO:

Aravinda Chakravarti of Johns Hopkins University in Baltimore, Maryland, was a leader of the research team. Professor Chakravarti said additional experiments are needed to confirm the results. But he said it appears that stem cell lines may include harmful cells over time. As a result, he says, the life of stem cells and their usefulness for medical purposes may be limited.

For years, human embryonic stem cell research has remained in laboratories. Scientists have been studying what the cells can do and how they can be controlled. In time, however, they hope that stem cells can be used to replace or repair tissue damaged by disease or injury.

VOICE ONE:

Stem cells taken from human embryos¹⁰ that are just days old have the ability to grow into other cells, such as heart, nerve or brain cells. Scientists hope to use collections of these specialized¹¹ cells for medical treatments. The cells could then be put into patients suffering from heart disease or cancer, for example.

This latest study could strengthen calls for President Bush to permit the use of federal money for new stem cell lines. American law restricts federal aid for experiments involving human embryos. This is because an embryo⁵ must be destroyed so that stem cells can be collected. Opponents of stem cell research say this destroys human life.

Some members of the United States Congress are seeking to ease the restrictions¹² on federal aid.

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VOICE TWO:

You are listening to SCIENCE IN THE NEWS in VOA Special English.

 
The butterflies' path is from Canada through the United States to Mexico
Each year, millions of monarch butterflies travel from Canada to Mexico and back again. The monarch is one of the few butterfly species that make a migratory¹³ trip. Every fall, monarchs¹⁴ gather in areas of Canada and the United States and fly to Mexico. This year, the migration is a little unusual. A group of humans will travel alongside the insects to record their trip.

The project is called Papalotzin. The word means "little butterfly" in the native Nahuatal language of central Mexico. Project director Francisco Gutierrez launched Papalotzin in an effort to help protect the butterflies for the future. The international wildlife-protection group WWF is providing support to the project.

Mister Gutierrez also is the pilot of what is called an ultralight airplane. It uses a very small engine and can only hold two people. There is no roof on the plane. The pilot and passenger are exposed to the weather in much the same way as the butterflies. Also, this ultralight has black-and-gold wings, just as the monarchs do.

VOICE ONE:

Mister Gutierrez spoke¹⁵ to VOA during a stop in Washington, D.C. He noted¹⁶ that the weather is a big question in the use of an ultralight. He said when the butterflies do not fly, the ultralight does not fly.

Mister Gutierrez and his crew launched the ultralight in late August from the northeastern Canadian city of Montreal. The crew is from Canada, the United States and Mexico. Mister Gutierrez and his team will make a movie about the butterflies.

The team members will record the migration. They also will make stops along the way to hold news conferences and other events. Monarch butterfly experts and environmentalists will take part.

VOICE TWO:

Monarch butterflies weigh less than one gram. They fly to different warmer homes in the winter depending on where they come from. A smaller group of monarchs that live west of the Rocky Mountains fly to trees along the coast of Southern California.

The larger group of monarchs live east of the Rockies. They travel even farther south. They spend their winters in the high mountain forests of central Mexico. The Papalotzin project is traveling with this group.

The butterflies' final stop will be about four thousand five hundred kilometers from their starting point. The trip takes about three months to complete. The butterflies stay in Mexico from November through March.

VOICE ONE:

The Mexican government has taken steps to protect the area that is the insects' winter home. Mexico created the Monarch Butterfly Biosphere¹⁷ Reserve in nineteen eighty-six. The main purpose is to protect the forests. They are important to the environment and local communities.

But the cutting down of trees continued. So the government agreed to create a larger reserve. WWF supported the effort.

In two thousand the Mexican government expanded the protected area by more than three hundred percent. The reserve now covers more than fifty-six thousand hectares.

The declaration of a bigger reserve cancelled logging permits held by local communities. But with the expanded area came a financial plan to provide economic support to the communities. Now, WWF says, people are paid for their conservation efforts.

But an official of the group says illegal logging continues to be a problem in the forests.

VOICE TWO:

Most monarch butterflies never get a chance to migrate. Most live only about a month. But once a year the species produces a special group. In late summer, longer-living monarchs are born. They live about seven months.

These butterflies make the trip to Mexico and spend the winter there. They give birth to their young on the way back north. Their young have the usual shorter lives.

The trip home to the northern United States and to Canada is really a flight of several generations. Butterflies are born, give birth and die along the way.

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VOICE ONE:

The World Heart Federation¹⁸ says two thirds of all children are not active enough. The group says about twenty-two million boys and girls under the age of five are severely¹⁹ overweight. Obese²⁰ children often become obese adults. And obesity²¹ increases the risk of heart disease and other disorders²².

The World Heart Federation says heart disease kills seventeen million people each year. Sunday, September twenty-fifth, was the yearly observance of World Heart Day. Heart experts urged parents to make sure their children get exercise and eat right. That means to eat a healthy and balanced diet, and to limit sugary drinks, sweets and eating between meals.

VOICE TWO:

Tobacco also increases the risk of heart disease, cancer and many other conditions. The World Heart Federation says the younger someone begins to smoke, the greater the risk. Half of the young people who continue to smoke as adults are likely to die from a smoking-related disease.

The group also says that almost half of all children live with a smoker²³. It says these children can breathe as much tobacco as in more than two thousand cigarettes. And that is just by the age of five.

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VOICE ONE:

SCIENCE IN THE NEWS was written by George Grow, Caty Weaver and Jill Moss. Cynthia Kirk was our producer. I'm Doug Johnson.

VOICE TWO:

And I'm Faith Lapidus. Internet users can find our programs at www.tingroom.com. To send us e-mail, write to [email protected]. We hope you join us again next week for more news about science, in Special English on the Voice of America.

1 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。

2 moss   

n.苔，藓，地衣

参考例句：

• Moss grows on a rock.苔藓生在石头上。
• He was found asleep on a pillow of leaves and moss.有人看见他枕着树叶和苔藓睡着了。

3 monarch   

n.帝王，君主，最高统治者

参考例句：

• The monarch's role is purely ceremonial.君主纯粹是个礼仪职位。
• I think myself happier now than the greatest monarch upon earth.我觉得这个时候比世界上什么帝王都快乐。

4 migration   

n.迁移，移居，（鸟类等的）迁徙

参考例句：

• Swallows begin their migration south in autumn.燕子在秋季开始向南方迁移。
• He described the vernal migration of birds in detail.他详细地描述了鸟的春季移居。

5 embryo   

n.胚胎，萌芽的事物

参考例句：

• They are engaging in an embryo research.他们正在进行一项胚胎研究。
• The project was barely in embryo.该计划只是个雏形。

6 embryonic   

adj.胚胎的

参考例句：

• It is still in an embryonic stage.它还处于萌芽阶段。
• The plan,as yet,only exists in embryonic form.这个计划迄今为止还只是在酝酿之中。

7 genetic   

adj.遗传的，遗传学的

参考例句：

• It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
• Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。

8 nutrients   

n.（食品或化学品）营养物，营养品( nutrient的名词复数 )

参考例句：

• a lack of essential nutrients 基本营养的缺乏
• Nutrients are absorbed into the bloodstream. 营养素被吸收进血液。 来自《简明英汉词典》

9 mutation   

n.变化，变异，转变

参考例句：

• People who have this mutation need less sleep than others.有这种突变的人需要的睡眠比其他人少。
• So far the discussion has centered entirely around mutation in the strict sense.到目前为止，严格来讲，讨论完全集中于围绕突变问题上。

10 embryos   

n.晶胚；胚，胚胎( embryo的名词复数 )

参考例句：

• Somatic cells of angiosperms enter a regenerative phase and behave like embryos. 被子植物体细胞进入一个生殖阶段，而且其行为象胚。 来自辞典例句
• Evolution can explain why human embryos look like gilled fishes. 进化论能够解释为什么人类的胚胎看起来象除去了内脏的鱼一样。 来自辞典例句

11 specialized   

adj.专门的，专业化的

参考例句：

• There are many specialized agencies in the United Nations.联合国有许多专门机构。
• These tools are very specialized.这些是专用工具。

12 restrictions   

约束( restriction的名词复数 )； 管制； 制约因素； 带限制性的条件（或规则）

参考例句：

• I found the restrictions irksome. 我对那些限制感到很烦。
• a snaggle of restrictions 杂乱无章的种种限制

13 migratory   

n.候鸟，迁移

参考例句：

• Many migratory birds visit this lake annually.许多候鸟每年到这个湖上作短期逗留。
• This does not negate the idea of migratory aptitude.这并没有否定迁移能力这一概念。

14 monarchs   

君主，帝王( monarch的名词复数 )

参考例句：

• Monarchs ruled England for centuries. 世袭君主统治英格兰有许多世纪。
• Serving six monarchs of his native Great Britain, he has served all men's freedom and dignity. 他在大不列颠本国为六位君王服务，也为全人类的自由和尊严服务。 来自演讲部分

15 spoke   

n.（车轮的）辐条；轮辐；破坏某人的计划；阻挠某人的行动 v.讲，谈（speak的过去式）；说；演说；从某种观点来说

参考例句：

• They sourced the spoke nuts from our company.他们的轮辐螺帽是从我们公司获得的。
• The spokes of a wheel are the bars that connect the outer ring to the centre.辐条是轮子上连接外圈与中心的条棒。

16 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。

17 biosphere   

n.生命层，生物圈

参考例句：

• The entire biosphere was becoming more transparent.整个生物圈越来越透明。
• The impact of modern technology on the biosphere is evident worldwide.现代技术对生物圈的影响在全世界是明显的。

18 federation   

n.同盟，联邦，联合，联盟，联合会

参考例句：

• It is a federation of 10 regional unions.它是由十个地方工会结合成的联合会。
• Mr.Putin was inaugurated as the President of the Russian Federation.普京正式就任俄罗斯联邦总统。

19 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。

20 obese   

adj.过度肥胖的，肥大的

参考例句：

• The old man is really obese,it can't be healthy.那位老人确实过于肥胖了，不能算是健康。
• Being obese and lazy is dangerous to health.又胖又懒危害健康。

21 obesity   

n.肥胖，肥大

参考例句：

• One effect of overeating may be obesity.吃得过多能导致肥胖。
• Sugar and fat can more easily lead to obesity than some other foods.糖和脂肪比其他食物更容易导致肥胖。

22 disorders   

n.混乱( disorder的名词复数 )；凌乱；骚乱；（身心、机能）失调

参考例句：

• Reports of anorexia and other eating disorders are on the increase. 据报告，厌食症和其他饮食方面的功能紊乱发生率正在不断增长。 来自《简明英汉词典》
• The announcement led to violent civil disorders. 这项宣布引起剧烈的骚乱。 来自《简明英汉词典》

23 smoker   

n.吸烟者，吸烟车厢，吸烟室

参考例句：

• His wife dislikes him to be a smoker.他妻子不喜欢他当烟民。
• He is a moderate smoker.他是一个有节制的烟民。