未知的味觉

听力材料来自普立特论坛，英语文本如下

 

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This is the VOA Special English Development Report.

There are new findings about an old method for keeping away insects. Scientists have uncovered the molecular workings of DEET.

DEET is the most widely used product for preventing insect bites. The scientists say their findings could lead to better insecticide products.

Fifty years ago, the United States Army and the 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 malaria. DEET has been shown to work on almost all insects, including ticks, which spread Lyme disease.

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 interferes with an insect’s ability to smell. Leslie Vosshall is a professor of neurogenetics at Rockefeller University in New York. She was the lead investigator of the study.

Her team carried out experiments with mosquitoes and fruit flies. She says they discovered proteins in the antennae 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.

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.

And that’s the VOA Special English Development Report, written by Brianna Blake.

 

 Secret of DEET Could Lead to New Insect Products: Play Now | Play in Popup

昨天英语学习VOA订阅地址esfeed.wangyutang.com的订阅数从一百多一下子降到43个，还感叹这一周不更新效果倒是真明显。今天听英语的时候，看我订阅的几个VOA听力文本的站点订阅数更少的可怜，还没有我这二手贩子多呢，想想那么大的站点没人订阅的确有些可惜，今天就把我订阅的一些英语VOA文本的RSS地址告诉大家，其实这些地址都自带VOA听力材料，只是因为伟大的墙的缘故，我们播放不了。
使用办法，下载OPML文件，导入到你自己的阅读器中就OK了。
点这里右键另存为下载OPML文件。什么是OPML文件？点这里了解。

This is the VOA Special English Education Report.

A science teacher from Prineville, Oregon, in the Pacific Northwest, is the new National Teacher of the Year.

Michael Geisen is thirty-five years old. He was a forester. But he decided he would rather work with growing minds than with growing trees. Seven years ago, he got a master’s degree in teaching and a job at Crook County Middle School. Crook County has high rates of poverty.

He brought new energy to the science department. He also created school projects to get parents involved in their children’s work.

One girl who was recently in his class said he could probably make it interesting to watch grass grow.

During lunch, his students come to his room to talk, get help, visit his turtle and sometimes join him in playing guitar. He writes songs and develops games about science. He says one of his goals as a teacher is to create people who will continue to learn throughout their lives.

Michael Geisen studied forest resource management and graduated with high honors from the University of Washington.

He says he tries to be creative with each activity. He does not like to use textbooks much. When students know that the work is local and useful to their lives, he says, they start to get interested.

On June first Michael Geisen will begin a year as a spokesman for education. The father of two young children will travel the country and the world.

The National Teacher of the Year program, a project of the Council of Chief State School Officers, began in nineteen fifty-two. The winner is chosen from among state teachers of the year.

President George Bush honored this year’s top teachers at the White House last week. He noted that in Michael Geisen’s first two years as head of the science department, scores on a state science test rose sharply at his school. And they are still rising. The president’s education reform law, the No Child Left Behind Act, expanded testing as a way to measure results.

But speaking at the White House, the new National Teacher of the Year said children are “not just numbers to be measured.”

MICHAEL GEISEN: “Students need to know that we value more than just being right all the time. We need to really honor their creativity. We need to honor their desire to learn useful skills that are going to be relevant to the twenty-first century world.

“These are skills such as innovation and creativity, people-skills like compassion and collaboration and the ability not to just know the details but to really see how it fits into the big picture. This is our real challenge, is to educate the entire child.”

And that’s the VOA Special English Education Report, written by Nancy Steinbach. I’m Steve Ember.

 

 From Forester to National Teacher of the Year: Play Now | Play in Popup

This is the VOA Special English Education Report.
—-以下为听力原文，听力材料来自普立特论坛—-

 

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