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SCIENCE IN THE NEWS - Now We Know Just How Sharks

(2010-08-04 09:19:46)


SCIENCE IN THE NEWS - Now We Know Just How Sharks Follow Their Nose to Their Next Meal



Written by Brianna Blake, Jim Tedder and Jerilyn Watson
Scientists have found that differences between the time when a shark's nostrils receive smells is more important than the strength of the odors
Scientists have found that differences between the time when a shark's nostrils receive smells is more important than the strength of the odors

FAITH LAPIDUS: This is SCIENCE IN THE NEWS in VOA Special English. I'm Faith Lapidus.

FAITH LAPIDUS:这里是VOA特别英语的新闻中的科学。我是Faith Lapidus.

BOB DOUGHTY: And I'm Bob Doughty. This week, we will tell how sharks use their wonderful sense of smell to find food. We also will tell about what some researchers are calling the world's oldest leather shoe. And, we will have some good news for people fifty years of age and up.


BOB DOUGHTY:我是Bob Doughty.这一周,我们讲一讲鲨鱼是如何利用自己奇妙的嗅觉去寻找食物的。我们还要讲一讲研究人员所谓的世界上最古老的皮鞋。并且我们还有一个针对50岁以上的人的好消息。


FAITH LAPIDUS: Few creatures on earth are as good as sharks at finding their dinners. People often say that a shark follows its nose to its meals. Now, scientists have learned more about how those noses work to help the much-feared fish direct its movements.

FAITH LAPIDUS:在世界上没有几种动物可以象鲨鱼那样善于寻找食物。人们经常说鲨鱼跟自己的嗅觉寻找食物。现在,科学家们已经获悉许多关于鲨鱼的鼻子是如何指导这种世界上最可怕的鱼类的行动的。

Recently published research questions a common belief about sharks.


Some people think that sharks simply follow the strongest smells that reach them to find their prey, or target. But scientists now can show that differences between the time when a shark's nostrils receive smells is more important than the strength of the odors.


Researchers Jayne Gardiner and Jelle Atema reported their findings in the publication Current Biology.


BOB DOUGHTY: The researchers studied small sharks called smooth dogfish, common to America's New England coast. The animals were swimming in a tank or container.

BOB DOUGHTY:研究人员研究了一种小型的鲨鱼“大星鲨”,常见于美国的新英格兰海岸,把这种动物放在一个油箱或容器里游泳。

The scientists placed special equipment on the sharks to direct odors directly to their nostrils. The smells were from squids -- a favorite meal of the smooth dogfish shark.


Then the scientists watched and recorded which way the sharks turned to follow the odor.

Ms. Gardiner said the delay between the arrival of the smell at each nostril could be as little as a half second or less. The animals turned and swam in the direction of the nostril that first received the odor. Ms. Gardiner said this was true even if the odor in the second nostril was stronger.



Following the odor received by the first nostril guided the sharks into smelly areas in the water. The fish then followed the odors to the squid.


FAITH LAPIDUS: The findings also led the researchers to consider why some sharks have strangely shaped heads. The hammerhead shark family is a good example. The name hammerhead describes the animal's wide, flat head. One theory is that the shape developed over the ages to improve this shark's sense of smell.

FAITH LAPIDUS:这可发现也让研究人员想到为什么有些鲨鱼有着奇怪形状的脑袋。双髻鲨家族是一个好的例子。双髻这个词描述了这种动物的宽宽的平平的脑袋。一个理论是这种形状是在提高这种鲨鱼的味觉的漫长的过程中形成的。

When hammerheads swim into clouds of odor, they usually do not swim straight on. Instead, their bodies are on an angle.


SCIENCE <wbr>IN <wbr>THE <wbr>NEWS <wbr>- <wbr>Now <wbr>We <wbr>Know <wbr>Just <wbr>How <wbr>Sharks

BOB DOUGHTY: Hammerhead sharks have nostrils that are more widely spaced than those of sharks with pointed noses. The placement creates a longer delay between the time the left and right nostrils receive an odor than in sharks with pointed noses.

BOB DOUGHTY:比起尖鼻子的鲨鱼来说,双髻鲨的鼻孔相距比较宽。鼻孔的这种宽距离,使得它比起尖鼻子的鲨鱼来左右鼻孔闻到气味的延迟时间比较大。

This suggests that animals with more widely spaced nostrils could attack from better positions while swimming fast. Ms. Gardiner believes this ability may have helped the development of hammerhead sharks over the ages.


Comparison of underwater odors is the idea behind some mechanical searching devices now in use by the military. These robots use odors to seek underwater bombs. Ms. Gardiner suggests that the current research with sharks may lead to better robotic devices.


Jayne Gardiner is a doctoral candidate at the University of South Florida. Professor Atema works with Boston University and the Marine Biological Laboratory at the Woods Hole Oceanographic Institution, both in Massachusetts.



Leather shoe, an estimated 5,500 years old
Leather shoe, an estimated 5,500 years old

FAITH LAPIDUS: Nothing fits like an old shoe -- especially if that shoe walked the earth five thousand five hundred years ago. Researchers in Armenia found the world's oldest leather shoe, and they say it was in surprisingly good condition.

FAITH LAPIDUS:没有比旧鞋子更合脚的了--特别是那鞋5500年以前已经在土地上行走。美国的研究人员发现了世界是最古老的皮鞋,并且他们说这鞋子的状况令人吃惊地好。

Doctoral student Diana Zardaryan of the Institute of Archeology found it in a cave near the border with Iran and Turkey. In her words, "even the shoe laces were preserved."

考古大学的博士生Diana Zardaryan 在伊朗和土耳其的边界附近的洞穴里发现了它。用她的话来说,“哪怕是鞋鞋带都保存得完好。”

It fact, the team of archeologists first thought it was about six or seven hundred years old. Then two laboratories in the United States and Britain did radiocarbon tests.

The tests showed it was four hundred years older than the Stonehenge formation in England -- and a thousand years older than the Great Pyramid of Giza in Egypt.



BOB DOUGHTY: The cool and dry conditions in the cave protected the shoe and other objects. So did a thick, solid layer of sheep dung covering the floor. This acted as a seal to prevent damage.

The shoe was made from a single piece of cowhide. The researchers believe the shoe was shaped to fit the wearer's right foot. The shoe is small -- a European size thirty-seven, or a women's size seven in the United States.

BOB DOUGHTY:洞穴的的清凉干燥的条件保护了这鞋子和其它的物品。地面上的一层厚厚的、坚实的绵羊粪也起到了保护作用。充当密封物保护鞋子免受损坏。


FAITH LAPIDUS: The lead author of the research says he does not know if the shoe was made for a man or a woman. Ron Pinhasi of University College in Cork, Ireland, says it could have fit a man from that period.

FAITH LAPIDUS:这个研究的首席作者?说他不知道这鞋子是女人穿的还是男人穿的。爱尔兰科克的大学里的 Ron Pinhasi 说在那个时代应该是男人穿的鞋子。

His team also found grass placed inside the shoe. The researchers say the grass might have been used to keep the wearer's foot warm. Or it could have been used to hold the shape of the shoe while it was not being worn.


The shoe is similar in design to "pampooties." These were shoes worn on the Aran Islands, in the west of Ireland, until the nineteen fifties. This kind of shoe appears to have been worn for thousands of years across a large area of Europe and beyond.



The researchers also found large containers of wheat, barley and apricots in the cave, along with a broken pot and sheep's horns. They also found the graves of children buried near the back of the cave. They do not know why all these things were found together in one place. They do not know what the purpose of the cave was.



The archeologists published their findings in the online scientific journal PloS One, from the Public Library of Science. They are continuing their work in Armenia. They say there are many other parts of the cave they have yet to explore.

考古学家们在网上科学杂志PloS One上公布了他们的发现,这个杂志是科学公共图书馆的杂志。他们现在还在亚美尼亚继续他们的研究工作。他们说这个洞穴还有另一些部分有待他们探索。

The oldest footwear of any kind ever found are sandals made of plant material. Scientists believe sandals found in the Arnold Research Cave in the American state of Missouri are about seven thousand five hundred years old.


That makes them about two thousand years older than the leather shoe found in Armenia.



FAITH LAPIDUS: Finally, old age does not sound exciting to most people. But a recent study offers good news for older adults.

FAITH LAPIDUS:归根到底,对于大多数从来说,年老听起来并不是令人愉快的。但是最近的研究给老年人带来了好消息。

It found that people become happier and experience less worry after they reach the age of fifty. In fact, by age eighty-five, people are happier with their life than when they are eighteen years old.


The findings came from a study of more than three hundred forty thousand adults living in the United States. The Gallup Organization questioned them by telephone in two thousand eight. At the time, the adults were between the ages of eighteen and eighty-five years old.


BOB DOUGHTY: The researchers asked questions about emotions like happiness, sadness and worry. They also asked about mental or emotional tension -- better known as stress.

BOB DOUGHTY:这项研究询问了一些关于情绪的问题,有高兴、悲伤和焦虑。他们还询问了心理上的和情绪上的紧张--也就是大家所熟知的压力。

Arthur Stone was a leader of the study. He works for the Department of Psychiatry and Behavioral Science at Stony Brook University in New York. His team found that levels of stress were highest among adults between the ages of twenty-two and twenty-five.


The study found that stress levels dropped sharply after people reached their fifties.


FAITH LAPIDUS: Surprisingly, people in their seventies and eighties were least likely to report feeling negative or harmful emotions.

FAITH LAPIDUS:令人吃惊的是,人们的到了70或80多岁的时候没有报告负面的或有害的情绪。

Happiness was highest among the youngest adults and those in their early seventies. The study showed that men and women had similar emotional patterns as they grew older. However, women reported more sadness, stress and worry than men at all ages.


The Proceedings of the National Academy of Sciences published a report about the study.


BOB DOUGHTY: Researchers do not know why happiness increases as people get older.

BOB DOUGHTY:研究人员不知道为什么当人变老的时候幸福感会增强。

One idea is that, as people age, they grow more thankful for what they have, and have better control of their emotions. They also spend less time thinking about bad experiences.


Professor Stone says the emotional patterns could be linked to changes in how people see the world, or maybe even changes in brain chemistry.


The researchers considered other possible influences, like having young children, being unemployed and being single. However, such influences did not affect the levels of happiness and well-being related to age.



FAITH LAPIDUS: This SCIENCE IN THE NEWS was written by Brianna Blake, Jim Tedder and Jerilyn Watson. Our producer was June Simms. I'm Faith Lapidus.


And I'm Bob Doughty. Join us again next week for more news about science in Special English on the Voice of America.


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