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Post archive for ‘英语学习’

爱尔兰发起儿童减肥运动

最新一项调查表明,在爱尔兰,大约2/3的孩子达不到推荐的运动量。这项调查由健康促进和食品安全大臣,玛丽.华莱士发起,由北爱的健康服务执委会,食品安全和健康促进协会执行。目前,在爱尔兰5到12岁的儿童中,11%的儿童超重,11%的儿童肥胖,超过一半的父母认为,如何让儿童吃的更健康真是一项具有挑战性的工作。

怎样挑选竞选伙伴成为难题

The candidates for president of the United States now face what some call the biggest decision of their campaigns. Republican John McCain and Democrat Barack Obama have to choose a vice president.

 
icon for podpress  Why the Search for a Running Mate Has Become a Bigger Deal [4:36m]: Play Now | Play in Popup

Agriculture report about cork

听力材料来自普立特论坛,英语文本如下

 
icon for podpress  water [4:00m]: Play Now | Play in Popup

查建英《国家公敌》(转贴)

ruanyifeng.com要每隔一段时间再去,每次都能发现一点好东西。这次转载国家公敌,只是想留给自己有时间的时候精读一下。也非常推荐你能读一下,一定不虚此行。

Secret of DEET Could Lead to New Insect Products

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.

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


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