Counting the number of miles traveled done by a product is a strange way of trying to tell the true situation of the environmental damage due to industry. Most food is transported around the world on container ships that are extremely energy efficient. It should be noticed that a ton of butter transported 25 miles in a truck to a farmers' market doesn't necessarily use less fuel on its journey than a similar product transported hundreds of miles by sea. Besides, the idea of “food miles” ignores the amount of fuel used in the production. It is possible to cut down your food miles by buying tomatoes grown in Britain rather than those grown in Ghana. The difference is that the British ones will have been raised in heated greenhouse and the Ghanaian ones in the open sun.

    What is the idea of “food miles” doesprovide, however, is the chance to cut out Third World countries from First World food markets. The number of miles traveled by our food should, as I see it, be regarded as a sign of the success of the global trade system, not a sign of damage to the environment.

    Last year my summer holiday was spoiled by my bringing along a modern convenience that was too convenient for my own good: the iPad. Instead of looking at nature, I checked my e-mail. Instead of paddling a small boat, I followed my Twitter feed（推特简讯）. Instead of reading great novels, I stuck to reading four newspapers each morning. I was behaving as if I were still in the office. My body was on vacation, but my head wasn't.

    So this year I made up my mind to try something different: withdrawal from the Internet. I knew it wouldn't be easy, since I'm bad at self-control. But I was determined. I started by giving the iPad to my wife.

    The cellphone signal at our house was worse than in the past, making my at tempts at cheating an experience in frustration （沮丧）. I was trapped, forced to go through with my plan. Largely breaking away from e-mail, Twitter and my favorite newspaper websites, I had few ways to connect to the world except for the radio—and how much radio can one listen to, really? I had to do what Ihad planned to do all along: read books.

    This experience has had a happy ending. With determination and the strong support of my wife, I won in my vacation struggle against the Internet, realizing finally that it was I, not the iPad, that was the problem. I knew I had won when we passed a Star bucks and my wife asked if I wanted to stop to use the Wi-Fi.“I don't need it,” I said．

    However, as we return to post-vacation life, a harder test begins: Can I continue when I'mback at work?

    There are times when the need to know what's being said right now is great. I have no intention of giving up my convenience completely. But I hope to resist the temptation to check my e-mail every five minutes, which leads to checking my Twitter feed and a website or two.

    I think a vacation is supposed to help you rest your brain to become more productive. Here I hope this one worked.

    Working with a group of baboons (狒狒）in the Namibian desert, Dr. Alecia Carter of the Department of Zoology，Cambridge University set baboons learning tasks involving a novel food and a familiar food hidden in a box. Some baboons were given the chance to watch another baboon who already knew how to solve the task, while others had to learn for themselves. To work out how brave or anxious the baboons were, Dr. Carter presented them either with a novel food or a threat in the form of a model of a poisonous snake.

    She found that personality had a major impact on learning. The braver baboons learnt, but the shy ones did not learn the task although they watched the baboon perform the task of finding the novel food just as long as the brave ones did. In effect, despite being made aware of what to do, they were still too shy to do what the experienced baboon did.

    The same held true for anxious baboons compared with calm ones. The anxious individuals learnt the task by observing others while those who were relaxed did not, even though they spent more time watching.

    This mismatch between collecting social information and using it shows that personality plays a key role in social learning in animals, something that has previously been ignored in studies on how animals learn to do things. The findings are significant because they suggest that animals may perform poorly in cognitive (认 知的）tasks not because they aren't clever enough to solve them，but because they are too shy or nervous to use the social information.

The findings may impact how we understand the formation of culture in societies through social learning. If some individuals are unable to get information from others because they don't associate with the knowledgeable individuals，or they are too shy to use the information once they have it，information may not travel between all group members, preventing the formation of a culture based on social learning.

    Miles was born in Alton, a city on the Mississippi River in Illinois on May 26, 1926. Miles's father was a dentist, while his mother was a music teacher. Miles had a good childhood, catching fish and riding horses with his older sister and younger brother. He was known as a naughty boy in school.

    He recalls his story, “By the age of 12, music had become the most important thing in my life.” His mother, a violinist herself, dearly wanted her son to play the violin. But brass (铜管) was Miles's calling, and he remembers arguments between their parents as his dad overruled her to fight his son's corner. He received his first trumpet (喇叭) in 1935 and began weekly music lessons with his father's friend Mr. Elwood, his life-long teacher.

    Talking about his school days, Miles said that Mr. Buchanan was the biggest influence on his life. He was the person who took Miles all the way into music at that time. He wanted to be a musician that he had dreamed.

    When he was 16, Miles met his girlfriend, Irene Birth. Although she was a beautiful young woman in many ways, it was her easy-going character that attracted Miles. At the weekends, Miles and Irene would take the bus over the Mississippi River to St Louis to watch movies and go dancing. Although Miles was too shy to really enjoy dancing, he always felt confident when he danced with Irene.

    When he turned 17, she persuaded him to ask for a job in his band—Eddie Handle's Blue Devils. It worked. Joining the band was a breakthrough for Miles, and marked the time when he first began to write and arrange music.

    We are naturally drawn to friends and colleagues with familiar voices, scientists have found. People prefer those who have a similar accent, intonation and tone of voice to themselves, they discovered.

    Previous research has focused on how male or female a voice sounds. Men with deeper voices and women with slightly higher voices were thought to sound more attractive, because they suggest a bigger or a smaller body.

    But the new study, published by a linguistics expert in Canada, suggests there is a more complex mechanism (机制) at play. Dr Molly Babel, from the University of British Columbia in Canada, said, “The voice is an amazingly flexible tool that we use to construct our identity. Very few things in our voices are changeless, so we felt that our preferences had to be about more than a person's shape and size.”

    She recorded 30 volunteers' voices and asked each to rate the others' attractiveness on a range from one to nine. Each participant was from western America, with similar accents. The people we assessed were all in the same dialect group, but they showed that dialect to different degrees.

     “We seem to like people who sound like we sound, and we like people who fit within what we know,” Dr Babel said. She also found that breathy voices in women—typified by the famous American actress Marilyn Monroe-were seen as more attractive.

    The breathy tone, caused by younger and thinner vocal cords (声带), implied youthfulness and health. A creaky (咯吱作响的) voice, suggesting a person has a cold, is tired or smokes, was seen as unattractive. The participants preferred men who spoke with a shorter average word length and deeper voices.

    You probably know who Marie Curie was, but you may not have heard of Rachel Carson. Of the outstanding ladies listed below, who do you think was the most important woman of the past 100 years?

    Jane Addams (1860-1935)

    Anyone who has ever been helped by a social worker has Jane Addams to thank. Addams helped the poor and worked for peace. She encouraged a sense of community(社区)by creating shelters and promoting education and services for people in need. In 1931, Addams became the first American woman to win the Nobel Peace Prize.

    Rachel Carson (1907-1964)

    If it weren't for Rachel Carson, the environmental movement might not exist today. Her popular 1962 book Silent Spring raised awareness(意识) of the dangers of pollution and the harmful effects of chemicals on humans and on the world's lakes and oceans.

    Sandra Day O'Connor (1930-present)

    When Sandra Day O'Connor finished third in her class at Stanford Law School, in 1952, she could not find work at a law firm because she was a woman. She became an Arizona state senator(参议员) and in 1981, the first woman to join the U. S. Supreme Court(最高法院). O'Connor gave the deciding vote in many important cases during her 24 years on the top court.

    Rosa Parks(1913-2005)

    On December 1,1955, in Montgomery, Alabama, Rasa Parks would not give up her seat on a bus to a white passenger. Her simple act landed Parks in prison. But it also set off the Montgomery bus boycott(抵制). It lasted for more than a year, and kicked off the civil-rights movement. "The only tired I was, was tired of giving in," said Parks.