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VOA慢速英语2012 SCIENCE IN THE NEWS - Youngest Type 1a Supernova Ever Observed

时间:2012-01-18 02:17来源:互联网 提供网友:nan   字体: [ ]
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SCIENCE IN THE NEWS - Youngest Type 1a Supernova Ever Observed

SHIRLEY GRIFFITH: This is SCIENCE IN THE NEWS, in VOA Special English. I’m Shirley Griffith.
STEVE EMBER: And I’m Steve Ember. Today, we tell about the discovery of what astronomers1 are calling the youngest type 1a supernova ever observed. We tell about an effort to improve the diet of New York City school children. We also tell why some chili2 peppers are hotter than others, and how listening to music can ease pain.
(MUSIC)
SHIRLEY GRIFFITH: Two teams of astronomers say the quick discovery of a supernova has helped to solve several mysteries in astronomy. Supernovas are intensely bright exploding stars. Astronomers sometimes use such explosions to measure distance in the universe.
The two teams recently reported findings from what they are calling the youngest type-1a supernova ever observed. They say the findings supported some long-held theories about what kind of stars explode to create supernovas.
STEVE EMBER: The scientists say the research provided the first evidence that small, dense3 dying stars called carbon-oxygen dwarfs5 become type-1a supernovas. These white dwarfs are often members of binary6 star systems. Such a system has two stars that orbit each other. A white dwarf4 explodes as a type-1a supernova when it takes too much material from its neighbor.
The young type-1a supernova was discovered in August. It is in the Pinwheel Galaxy7 -- about twenty-one million light years from Earth. A light-year is the distance light travels in one year – about ten trillion kilometers. That may sound like a great distance. But this galaxy is somewhat close to our own Milky8 Way Galaxy. The nearness of the huge event helped scientists make detailed9 observations.
SHIRLEY GRIFFITH: Type-1a supernovas all release about the same amount of light. That helps astronomers know how far away they are from Earth. So, bright type-one-a supernovas are closer than not-so-bright ones.
The astronomers say they discovered the supernova only eleven hours after the star exploded. They say this was the first time a star’s thermonuclear explosion has ever been observed so soon after it happened.
Scientists from the University of California at Berkeley and the California Institute of Technology were among the teams that carried out the research. Two related reports about the supernova were published in the scientific journal, Nature.
(MUSIC)
STEVE EMBER: The Centers for Disease Control and Prevention says every third adult and almost every fifth child in America is obese10. But health officials in New York City say their work has caused rates of those seriously overweight to drop sharply.
Alex Schimke is a sixth grade student who is not obese. He says he likes fruits, especially strawberries. But like most children, he loves cakes, candy and other sweets.
ALEX SCHIMKE: “Are you going to eat the cake or are you going to eat the apple for health? You’re obviously going to eat the apple, but you want the cake.”
Why the cake and not the apple?
ALEX SCHIMKE: “Because it’s yummy!”
SHIRLEY GRIFFITH: New York City Health Commissioner11 Thomas Farley knows children love foods that are sometimes not good for them.
THOMAS FARLEY: “Children have a natural preference for sweets, more so than adults. On the other hand, as adults, we choose what to put in front of our children.”
Dr. Farley says New York has increased the amount of physical activity in schools, and improved the food available in school cafeterias. Alex Schimke has noted12 the difference.
ALEX SCHIMKE: “They do have apples. Oh, yes! And they have a salad bar.”
Alex also noted that vending13 machines at the school now sell vitamin water instead of sugary drinks.
STEVE EMBER: Dr. Farley says obesity14 rates in America began rising about thirty years ago. In the twentieth century, many people stopped doing physical labor15 on farms and in factories. They began working in offices, where they spend most of the time sitting down.THOMAS FARLEY: “Physical activity has all but disappeared out of most people’s lives, unless they make it a separate task. At the same time, and even more important, food has increasingly become cheap, ready to eat, available everywhere, and so people have adopted habits to sort of snack constantly.”
Dr. Farley says the total childhood obesity rate in New York is still a too-high twenty percent. But he says he is happy that it has fallen at all. And for the first time in many years the rate is down to ten percent among five and six year olds. Dr. Farley says he believes that may mean those children will eat healthy throughout their lives.
(MUSIC)
SHIRLEY GRIFFITH: For spicy16 food lovers, hot peppers, or chilies17, are a great addition to any meal. There are many different kinds of hot peppers. Some are much hotter than others. But what makes some chili peppers so hot and others not?
An American researcher has found answers to some of the questions about a pepper’s intensity18. Joshua Tewksbury works at the University of Washington in Seattle. For years, he has studied the small, dried fruit of pepper plants during travels to Central and South America. Among his favorites is the Capsicum chacoense, found in Bolivia. Like many chilies, this one can be destroyed if a fungus19 enters the pepper through holes made by insects. This organism is called Fusarium.
STEVE EMBER: To fight off the attack, the pepper produces a chemical called capsaicin. This is the same chemical that gives peppers their heat. However, not every pepper contains capsaicin. Even within one pepper plant, there may be some peppers with capsaicin and others without it. Those containing the chemical are protected from the fungus.
So why do only some peppers produce capsaicin? That is the question Professor Tewksbury set out to answer. With the help of an assistant, he collected more than three hundred chili plants from a three hundred-kilometer area in Bolivia. Within this area were different climates. Some plants grew in desert-like conditions, while others were from a very wet climate.
SHIRLEY GRIFFITH: Professor Tewksbury and his assistant found that among the chilies growing in the dry places, only about fifteen to twenty percent were hot. By comparison, one hundred percent of the chilies growing in wet conditions were hot.
They also found that hot chilies growing in dry areas need more water. Because the fungus is less of a threat in dry weather, the chilies in those areas were less likely to produce the heat-making capsaicin. In wet areas, the pepper produced more capsaicin to defend itself.
STEVE EMBER: The researchers tested their findings back at the University of Washington. Three hundred thirty chili plants were grown under the same conditions. Then they were separated into two groups. One received a lot of water. The other plants received the amount of water they would get in a dry climate in Bolivia.
The researchers found that the hot peppers use up more water as a way to protect themselves from fungus. Their findings were published in the Proceedings20 of the Royal Society B.
(MUSIC)
SHIRLEY GRIFFITH: Maybe a little of this … (Music)
… or that … (Music).
Or even this … (Music)
… could be just what the doctor ordered.
Music seems to have a magical power when it comes to easing pain. This is what researchers at the University of Utah Pain Research Center have found. They reported results of their latest study in “The Journal of Pain.”
STEVE EMBER: The researchers asked one hundred forty-three people to listen to music while they were being given an electrical shock to the finger. The test subjects were told to listen carefully and note any sounds that were pleasing, or any that seemed to be different from the others.
The researchers measured how the patient’s brain reacted during the experiment. They also watched their eyes for evidence of any reaction to the pain. Some of the test subjects said they were very nervous about feeling pain. These people were said to have “high anxiety.” Others said they had no great fear of feeling pain.
SHIRLEY GRIFFITH: The lead researcher was David H. Bradshaw of the University of Utah in Salt Lake City. His team found that listening to music seemed to reduce the amount of pain some people feel. They also found that those people with “high anxiety” were helped most by the music. The researchers had feared that those most afraid of pain would not be able to listen carefully to the sounds they were hearing. But that was not the case.
So, if listening to music helps to lessen21 pain, what kind of music should we listen to? Mr. Bradshaw says the kind of music is not important. He says the most important thing is to listen to the music very carefully, almost as if you were studying for some kind of musical test.
The Utah researchers believe that music may affect some “pathways” in the human brain. They think musical sounds activate22, or turn on, “sensory” pathways. If the pathway is being used by the senses, like hearing music, it cannot be used to make that part of the brain feel pain.
SHIRLEY GRIFFITH: This SCIENCE IN THE NEWS was written by Brianna Blake, Christopher Cruise and Jim Tedder23. Our producer was June Simms. I’m Shirley Griffith.
STEVE EMBER: And I’m Steve Ember. Join us again next week for more news about science in Special English on the Voice of America.


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1 astronomers 569155f16962e086bd7de77deceefcbd     
n.天文学者,天文学家( astronomer的名词复数 )
参考例句:
  • Astronomers can accurately foretell the date,time,and length of future eclipses. 天文学家能精确地预告未来日食月食的日期、时刻和时长。 来自《简明英汉词典》
  • Astronomers used to ask why only Saturn has rings. 天文学家们过去一直感到奇怪,为什么只有土星有光环。 来自《简明英汉词典》
2 chili JOlzm     
n.辣椒
参考例句:
  • He helped himself to another two small spoonfuls of chili oil.他自己下手又加了两小勺辣椒油。
  • It has chocolate,chili,and other spices.有巧克力粉,辣椒,和其他的调味品。
3 dense aONzX     
a.密集的,稠密的,浓密的;密度大的
参考例句:
  • The general ambushed his troops in the dense woods. 将军把部队埋伏在浓密的树林里。
  • The path was completely covered by the dense foliage. 小路被树叶厚厚地盖了一层。
4 dwarf EkjzH     
n.矮子,侏儒,矮小的动植物;vt.使…矮小
参考例句:
  • The dwarf's long arms were not proportional to his height.那侏儒的长臂与他的身高不成比例。
  • The dwarf shrugged his shoulders and shook his head. 矮子耸耸肩膀,摇摇头。
5 dwarfs a9ddd2c1a88a74fc7bd6a9a0d16c2817     
n.侏儒,矮子(dwarf的复数形式)vt.(使)显得矮小(dwarf的第三人称单数形式)
参考例句:
  • Shakespeare dwarfs other dramatists. 莎士比亚使其他剧作家相形见绌。 来自《简明英汉词典》
  • The new building dwarfs all the other buildings in the town. 新大楼使城里所有其他建筑物都显得矮小了。 来自辞典例句
6 binary jybzWZ     
adj.二,双;二进制的;n.双(体);联星
参考例句:
  • Computers operate using binary numbers.计算机运行运用二进位制。
  • Let us try converting the number itself to binary.我们试一试,把这个数本身变成二进制数。
7 galaxy OhoxB     
n.星系;银河系;一群(杰出或著名的人物)
参考例句:
  • The earth is one of the planets in the Galaxy.地球是银河系中的星球之一。
  • The company has a galaxy of talent.该公司拥有一批优秀的人才。
8 milky JD0xg     
adj.牛奶的,多奶的;乳白色的
参考例句:
  • Alexander always has milky coffee at lunchtime.亚历山大总是在午餐时喝掺奶的咖啡。
  • I like a hot milky drink at bedtime.我喜欢睡前喝杯热奶饮料。
9 detailed xuNzms     
adj.详细的,详尽的,极注意细节的,完全的
参考例句:
  • He had made a detailed study of the terrain.他对地形作了缜密的研究。
  • A detailed list of our publications is available on request.我们的出版物有一份详细的目录备索。
10 obese uvIya     
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。
11 commissioner gq3zX     
n.(政府厅、局、处等部门)专员,长官,委员
参考例句:
  • The commissioner has issued a warrant for her arrest.专员发出了对她的逮捕令。
  • He was tapped for police commissioner.他被任命为警务处长。
12 noted 5n4zXc     
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。
13 vending 9e89cb67a07fe419b19a6bd5ee5210cc     
v.出售(尤指土地等财产)( vend的现在分词 );(尤指在公共场所)贩卖;发表(意见,言论);声明
参考例句:
  • Why Are You Banging on the Vending Machine? 你为什么敲打这台自动售货机? 来自朗文快捷英语教程 2
  • Coca-Cola had to adapt almost 300,000 vending machines to accept the new coins. 可口可乐公司必须使将近三十万台自动贩卖机接受新货币。 来自超越目标英语 第5册
14 obesity Dv1ya     
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。
15 labor P9Tzs     
n.劳动,努力,工作,劳工;分娩;vi.劳动,努力,苦干;vt.详细分析;麻烦
参考例句:
  • We are never late in satisfying him for his labor.我们从不延误付给他劳动报酬。
  • He was completely spent after two weeks of hard labor.艰苦劳动两周后,他已经疲惫不堪了。
16 spicy zhvzrC     
adj.加香料的;辛辣的,有风味的
参考例句:
  • The soup tasted mildly spicy.汤尝起来略有点辣。
  • Very spicy food doesn't suit her stomach.太辣的东西她吃了胃不舒服。
17 chilies 792c44b1b02c06a551b8df5efc038fe4     
n.红辣椒( chili的名词复数 )
参考例句:
  • Some people like to harvest the plants, when the chilies are green. 一些人喜欢在辣椒长成绿色的时候就采摘。 来自互联网
  • Sprinkle with scallions and sliced chilies and served hot. 洒上葱粒、辣椒丝,趁热上桌。 来自互联网
18 intensity 45Ixd     
n.强烈,剧烈;强度;烈度
参考例句:
  • I didn't realize the intensity of people's feelings on this issue.我没有意识到这一问题能引起群情激奋。
  • The strike is growing in intensity.罢工日益加剧。
19 fungus gzRyI     
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。
20 proceedings Wk2zvX     
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
21 lessen 01gx4     
vt.减少,减轻;缩小
参考例句:
  • Regular exercise can help to lessen the pain.经常运动有助于减轻痛感。
  • They've made great effort to lessen the noise of planes.他们尽力减小飞机的噪音。
22 activate UJ2y0     
vt.使活动起来,使开始起作用
参考例句:
  • We must activate the youth to study.我们要激励青年去学习。
  • These push buttons can activate the elevator.这些按钮能启动电梯。
23 tedder 2833afc4f8252d8dc9f8cd73b24db55d     
n.(干草)翻晒者,翻晒机
参考例句:
  • Jim Tedder has more. 吉姆?特德将给我们做更多的介绍。 来自互联网
  • Jim Tedder tells us more. 吉姆?泰德给我们带来更详细的报道。 来自互联网
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TAG标签:   VOA慢速英语  SCIENCE  Type  SCIENCE  Type
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