SCIENCE IN THE NEWS - Findings About Air Pollution and Heart

SCIENCE IN THE NEWS - Findings About Air Pollution and Heart Disease / Fossils from the 'Missing Years' in Africa / U.S. Bans...
By Caty Weaver¹

Broadcast: Tuesday, January 13, 2004

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VOICE ONE:

This is SCIENCE IN THE NEWS, in VOA Special English. I'm Bob Doughty².

VOICE TWO:

And I'm Sarah Long. This week -- fossils help bring light to a mysterious time in prehistoric³ Africa.

VOICE ONE:

New findings about air pollution: Could it be worse for the heart than the lungs?

VOICE TWO:

And, in the United States, the government acts to ban a weight-loss product.

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VOICE ONE:

Researchers say they have identified animal fossils from twenty-seven-million years ago in what is now Ethiopia. The remains⁴ are from the middle of a time called the "missing years" or the "dark period." This is because scientists have so little information about the mammals that lived then.

The period began thirty-two-million years ago. Africa and Arabia were a single continent, a huge island known as Afro-Arabia. The period ended twenty-four-million years ago, after a land bridge formed with Eurasia.

VOICE TWO:

John Kappelman is an anthropologist⁵ at the University of Texas in Austin and leader of the American and Ethiopian search team. Mister Kappelman says eight million years is a long time to lack information about a continent. He says scientists have only been able to guess what happened to African mammals during that period.

The remains found in the Chilga area of Ethiopia offer important evidence.

VOICE ONE:

The remains include teeth, skull⁶ pieces and other bones. The scientists found them in a farming area about two-thousand meters above sea level, in the highlands of Ethiopia. Satellite pictures helped the researchers decide where to dig. The fossils came from about seventy different digs. The magazine Nature published the findings.

The scientists say the fossils come from before large numbers of animals began to arrive in Africa from Europe and Asia. The fossils also show that some animals existed millions of years before scientists had thought.

VOICE TWO:

The researchers found several kinds of ancient proboscideans. These are animals with trunks. Modern elephants are proboscideans. Scientists have long thought elephants began in Africa. They say this discovery proves that theory. The ancestors weighed about one-thousand kilograms, a lot smaller than African elephants today.

John Kappelman says the elephant ancestors were one of the few African mammals that survived the invasion of mammals from Eurasia. He says elephants got their start in Africa during the eight-million-year period, and then spread around the world.

VOICE ONE:

 
Graphic⁷ Image
The researchers also found the remains of an ancient animal with two horns on its head, called the arsinoithere. The scientists were excited, because this is the youngest set of such remains yet discovered. The animal is much larger than its ancestors. Earlier forms were about the size of pigs. But the arsinoithere found at Chilga was about two meters tall and weighed more than two tons.

They were similar to the modern rhinoceros⁸. The two are not related. In fact, scientists thought arsinoitheres had disappeared from the Afro-Arabian continent once rhinos⁹ arrived from Eurasia. One researcher says it now appears they did not compete for survival.

Scientists say they expect more discoveries to come about the mammals that lived during the so-called missing years.

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VOICE TWO:

A study finds that air pollution is worse for the heart than the lungs.The American Heart Association published the findings in its magazine, Circulation.

Researchers used information given by more than half-a-million adults between nineteen-eighty-two and nineteen-ninety-eight. The information is from a continuing study by the American Cancer Society on cancer prevention. The study included people thirty and older living in cities where officials kept records on air pollution.

VOICE ONE:

During the sixteen-year period, one in five of the people in the study died. The scientists found that heart disease caused about forty-five percent of the deaths. Only eight percent of the people died from diseases of the breathing system.

The researchers compared the information with air pollution records from more than one-hundred-fifty cities. The scientists controlled for things that increase the risk of heart disease, like smoking and being overweight. Still, they found a stronger link between air pollution and heart disease than respiratory disease.

VOICE TWO:

Arden Pope of Brigham Young University in Provo, Utah, led the study. He says air pollution is not the main cause of heart disease. But, he says, breathing polluted air causes swelling¹⁰ and worsens disease in the arteries¹¹ of the blood system. He says this affects the ability of the heart to operate effectively. The study also suggests that air pollution harms the nervous system, leading to abnormal heartbeat.

 
Graphic Image
The study involved air polluted by small particles of soot¹². Vehicles that use diesel¹³ fuel create a lot of soot. So do some factories. But it is also released into the air by burning wood and other substances including animal waste and vegetable oil for fuel.

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VOICE ONE:

Soot was cause for a different concern in another recent study. Scientists with the American space agency, NASA, suggest it as a major cause of global warming. The NASA researchers say soot may be responsible for twenty-five percent of global warming observed over the past century.

With computers they recreated the effects of industrial gases and other influences on world climate. They say carbon dioxide and other gases that trap heat have been the main cause of recent global warming, and will remain so. Still, they say soot may be worse than has been thought.

The study says the problem is how soot interacts with snow and ice.

VOICE TWO:

Snow and ice have highly reflective surfaces. A lot of the sunlight that hits them is forced back up toward the sky. This helps prevent melting. But the scientists say the problem develops when snowflakes pick up fine particles of soot as they fall. The black carbon in soot reduces the ability of snow and ice to reflect sunlight. Instead, the black soot absorbs the energy and warmth, and causes melting.

James Hansen and Larissa Nazarenko of the Goddard Institute for Space Studies reported the findings. They estimate that soot particles in snow reduced reflectivity by three percent in northern land areas of the world. Their estimate for the Arctic is one-and-a-half percent.

VOICE ONE:

The scientists say the soot causes the melting season of glaciers¹⁴ to begin earlier and last longer. This has a large effect, they say, because wet snow is much darker than dry snow. So the problem increases.

The scientists estimate that soot is two times as effective as carbon dioxide in changing surface air temperatures. But they say the good news is that cleaner diesel engines and other technologies are being developed to reduce soot.

The study is in the Proceedings¹⁵ of the National Academy of Sciences.

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VOICE TWO:

In the United States, the government is acting¹⁶ to ban the sale of ephedra as a product to help people lose weight. Ephedra is a plant that contains ephedrine and pseudoephedrine. These substances can increase a person's energy level and cause weight loss. However, officials warn that ephedra also raises blood pressure. Ephedra has been linked to heart attacks, strokes, seizures¹⁷ and deaths.

The secretary of Health and Human Services announced the ban. Tommy Thompson urged people to stop using ephedra even before the ban takes effect. He said he did not want to delay the announcement, because people often try to lose weight at the start of a new year.

VOICE ONE:

The market has grown sharply for herbal products known as dietary supplements. Companies do not have to prove them safe and effective the way drug makers¹⁸ do. In nineteen-ninety-four, Congress limited the ability of the Food and Drug Administration to take action against supplements. This is the first ban since then.

The ban will not include the version of ephedra used in medicines to treat breathing infections. Ephedra has long been used for this purpose as a traditional medicine in China, where the plant is called ma huang.

(THEME)

VOICE TWO:

SCIENCE IN THE NEWS was written by Caty Weaver and produced by Cynthia Kirk. I'm Sarah Long.

VOICE ONE:

And, I'm Bob Doughty. Join us again next week for another program 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 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。

3 prehistoric   

adj.（有记载的）历史以前的，史前的，古老的

参考例句：

• They have found prehistoric remains.他们发现了史前遗迹。
• It was rather like an exhibition of prehistoric electronic equipment.这儿倒像是在展览古老的电子设备。

4 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。

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 skull   

n.头骨；颅骨

参考例句：

• The skull bones fuse between the ages of fifteen and twenty-five.头骨在15至25岁之间长合。
• He fell out of the window and cracked his skull.他从窗子摔了出去，跌裂了颅骨。

7 graphic   

adj.生动的，形象的，绘画的，文字的，图表的

参考例句：

• The book gave a graphic description of the war.这本书生动地描述了战争的情况。
• Distinguish important text items in lists with graphic icons.用图标来区分重要的文本项。

8 rhinoceros   

n.犀牛

参考例句：

• The rhinoceros has one horn on its nose.犀牛鼻子上有一个角。
• The body of the rhinoceros likes a cattle and the head likes a triangle.犀牛的形体像牛，头呈三角形。

9 rhinos   

n.犀牛（rhino的复数形式）

参考例句：

• There are many reports of people taming and even training Indian rhinos. 有许多关于人们驯养甚至训练印度犀牛的记载。 来自辞典例句
• The rhinos had fed during the night in the rice fields of these villagers. 犀牛夜里在这些村民的庄稼地里也已吃饱了。 来自辞典例句

10 swelling   

n.肿胀

参考例句：

• Use ice to reduce the swelling. 用冰敷消肿。
• There is a marked swelling of the lymph nodes. 淋巴结处有明显的肿块。

11 arteries   

n.动脉( artery的名词复数 )；干线，要道

参考例句：

• Even grafting new blood vessels in place of the diseased coronary arteries has been tried. 甚至移植新血管代替不健康的冠状动脉的方法都已经试过。 来自《简明英汉词典》
• This is the place where the three main arteries of West London traffic met. 这就是伦敦西部三条主要交通干线的交汇处。 来自《简明英汉词典》

12 soot   

n.煤烟，烟尘；vt.熏以煤烟

参考例句：

• Soot is the product of the imperfect combustion of fuel.煤烟是燃料不完全燃烧的产物。
• The chimney was choked with soot.烟囱被煤灰堵塞了。

13 diesel   

n.柴油发动机，内燃机

参考例句：

• We experimented with diesel engines to drive the pumps.我们试着用柴油机来带动水泵。
• My tractor operates on diesel oil.我的那台拖拉机用柴油开动。

14 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）

15 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

16 acting   

n.演戏，行为，假装；adj.代理的，临时的，演出用的

参考例句：

• Ignore her,she's just acting.别理她，她只是假装的。
• During the seventies,her acting career was in eclipse.在七十年代，她的表演生涯黯然失色。

17 seizures   

n.起获( seizure的名词复数 )；没收；充公；起获的赃物

参考例句：

• Seizures of illicit drugs have increased by 30% this year. 今年违禁药品的扣押增长了30%。 来自《简明英汉词典》
• Other causes of unconsciousness predisposing to aspiration lung abscess are convulsive seizures. 造成吸入性肺脓肿昏迷的其他原因，有惊厥发作。 来自辞典例句

18 makers   

n.制造者，制造商（maker的复数形式）

参考例句：

• The makers of the product assured us that there had been no sacrifice of quality. 这一产品的制造商向我们保证说他们没有牺牲质量。
• The makers are about to launch out a new product. 制造商们马上要生产一种新产品。 来自《简明英汉词典》