A sense of humor is something highly valued. A person who has a great sense of humor is often considered to be happy and socially confident. However, humor is a double-edged sword. Sometimes it can damage self-respect and annoy others.

    People who use bonding humor tell jokes and generally lighten the mood. They're thought to be good at reducing the tension in uncomfortable situations. They often make fun of their common experiences, and sometimes they may even laugh off their own misfortunes. The basic message they deliver is: We're all alike, we find the same things funny, and we're all in this together.

    Put-down humor, on the other hand, is an aggressive type of humor used to criticize others through teasing. When it's aimed against politicians, as it often is, it's extremely funny and mostly harmless. But in the real world, it may have a harmful effect. An example of such humor is telling friends an embarrassing story about another friend. When challenged about their teasing, the put-down jokers might claim that they are "just kidding," thus allowing themselves to avoid responsibility. This type of humor, though considered by some people to be socially acceptable, may hurt the feelings of the one being teased and thus have a bad effect on personal relationships.

    Finally, in hate-me humor, the joker is the target of the joke for the amusement of others. This type of humor was used by comedians John Belushi and Chris Farley—both of whom suffered for their success in show business. A small amount of such humor is charming, but routinely offering oneself up to be embarrassed destroys one's self-esteem, and fosters depression and anxiety.

    So it seems that being funny isn't necessarily an indicator of good social skills and well-being. In certain cases, it may actually have a negative effect on interpersonal relationships.

    I was working the overnight shift in a remote hospital in the Rocky Mountains. Late in the evening, a young African teenager was brought into the emergency department. He lived at sea level and had never been in the mountains. After skiing all day, he felt really ill. Everyone assumed it was altitude sickness.

    He was sweating and had abdominal (腹部的) pain. His heart rate increased. We sent off his lab work, and his blood sugar came back at almost 600 — normal is less than 100. His platelets (血小板), necessary for stopping bleeding, came in at 10,000; they should have been over 150,000. I did an ultrasound of his abdomen, and it looked like his belly was full of blood. This wasn't altitude sickness. And in the short time I'd been trying to figure out what was wrong, he was getting sicker. The friends he was traveling with were terrified, and rightly so.

    The mystery was finally solved with an old-fashioned microscope. When we looked at his blood, we saw some sickled (镰形的) red blood cells. That's how we were able to diagnose sickle cell trait. If you have sickle cell trait — which means you got the sickle cell gene from just one parent instead of two — you have no symptoms at low altitude, but high altitude can sometimes cause the red blood cells to turn into sickle shapes and take oxygen from vital organs. This teenager didn't know he had it, but the effect of the altitude on his blood cells was so extreme that after just a short time in the mountains, he suffered great pain.

    He needed platelets immediately, but we didn't have enough at the remote hospital. And there was a snowstorm, so the medical helicopters couldn't fly. It was a scary night. Just as we were abandoning all hope, we met an ambulance that drove halfway up from the city with blood products and transferred him to the city hospital for emergency surgery. The story has a happy ending: He recovered fully.

    E-mail systems at thousands of companies and government offices around the world were attacked by a virus(病毒)called “Melissa” that disguises(伪装)itself as an “important message from a friend. In spite of a weekend of warnings，more than 50 000 computers at about 100 places around the world have been attacked by the virus，computer security experts said on Monday.

    The virus began to show up last Friday and spread rapidly on Monday by making computers fire off dozens of infected(被传染的)e-mails. Although the virus causes no serious damage to a computer，its effect was far reaching.

    To make matters worse，a similar virus called “Papa” was discovered on Monday. Papa is programmed to send out even more infected e-mails than Melissa.

    The Melissa virus comes in the form of an e-mail，usually containing the subject line“Important Message”. It appears to be from a friend. The body of the e-mail message says，“Here is that document you asked for...,don't show it to anyone else.” Attached(附)to the message is a document file.

    Once the user opens that file，the virus digs into the user's address book and sends infected documents to the first 50 addresses. E-mails from the Papa virus include an attached spreadsheet(电子数据文件)file. When the user opens that file，the virus sends 60 infected e-mails.

    The reason why this is spreading so fast is that you are getting it from people you know. You should never open documents or attachments from people you don't know. People who get an unexpected e-mail with the “important message” subject line should delete it immediately and not open the message.

    According to findings of a survey by Citi and Seventeen Magazine, nearly four out of five (almost 80 percent) college students work while attending college, with the average work load of 19 hours per week. But should college students work while at college? Many factors should be considered.

    One benefit of working while in college is that it can help build your resume, regardless of whether the job is in your field, according to an article at Scholarships.com. "If you're lucky enough to find a job that closely relates to your major, you could get a leg up on the rest of your class once you graduate, because you'll have more experience in your chosen field," according to the article.

    Perhaps the most compelling reason for working while earning a degree is the money. While it's unlikely to entirely finance your education through a part-time or full-time job, you can still make quite a dent(削减)in the college bill by working.

    But some students prefer not to work while earning a degree so they can focus on getting the best grades. It's true that you'll have more time to stay at school if you don't work, provided you use that time wisely. If you feel like even 10-15 hours a week of work will hurt your grades, then perhaps you should not consider working.

    Working a part-time or full-time job can take away time from social activities, according to a You University TV article. "Trying to balance a job and your college studies, and taking a job can cut down your time to hang out with friends," according to writer Dave Potts.

    In addition to missing out on hanging out with your friends, working during college could prevent you from attending a number of campus events, such as movies on the lawn or football games. While you may be able to land a job that's flexible, it seems unlikely they'll let you choose your own schedule.

    So should students work at college? The decision should be made on a case-by-case basis. Some students can also thrive in school while working, whereas others can't.

    People born in winter are more likely to suffer mental health disorders, according to a recent study carried out by researchers at Vanderbilt University in Tennessee.

    Researchers raised baby mice from birth to weaning (断奶) in either “summer” light cycles of 16 hours of light and 8 hours of dark or “winter” cycles of 8 hours of light and 16 hours of dark. A third group experienced 12 hours of light and 12 hours of dark a day.

    Then half the winter mice stayed in a winter cycle, while half switched to a summer schedule. The summer mice were similarly split. The mice raised in equal periods of light and dark were split into three groups, one of which stayed on the 12­hour schedule, one of which joined the winter group, and one of which joined the summer group.

    After 28 days, it turns out the summer­born mice behaved the same whether they stayed on the summer cycle or switched to winter. But among the winter­born mice, those that stayed in winter kept their previous schedule, while those that switched to summer stayed active for an extra hour and a half, which indicates that mice born and weaned in a winter light cycle showed dramatic disruptions（破坏） in their biological clocks.

    The finding is the first of its kind in mammals, and it could explain why people born in winter are at higher risk for mental health disorders.

    “We know that the biological clock regulates(管理) mood in humans,” said study researcher McMahon. “If the mechanism (机制) similar to the one that we found in mice operates in humans, then it could not only have an effect on a number of behavioral disorders, but also have a more general effect on personality.”

    The United States will introduce a new and comprehensive(综合的) exam for students who seek to study in American and other English-speaking countries, Xinhua News Agency reported from New York.

    The exam, which stands for a great change from the current English level test, was disclosed by Theresa Chang Wei Jen, associate director of the International Service of the US College Board, America's leading educational organization.

    The Advanced Placement International English Language (APIEL) will be offered for the first time throughout the world on May 10, 2002, said Jen.

    However, the APIEL is a strange title to most Chinese students, and it is unlikely to soon gain the similarity of other already existing exams, such as the TOEFL(Test of English as a Foreign Language), the GRE(Graduate Record Examination), or the IELTS(International English Language Testing System).

    "I have never heard of such a test and I would prefer the IELTS if I need another exam," said Xu Jingyan, a graduating student from Beijing University of Aeronautics and Astronautics, who wants to study in England and has already taken the TOEFL.

    Most of Xu's classmates have never heard of the APIEL. "The APIEL is designed for international students who wish to get university studies in English-speaking countries, including the United States, Britain, Canada, and Australia." said Jen.

    The APIEL has been adopted, said Jen, because the TOEFL can no longer accurately reflect the abilities of students of using the English language comprehensively in an academic environment. Xinhua reported that a fairly large number of foreign students who earned high scores in TOEFL exam turned out to be very ordinary educational performers after admission.

    Compared with the TOEFL, the APIEL measures a student's ability to read, write, speak and understand English through testing his or her skills in listening comprehension, speaking with accuracy(精确) and resourcefulness, and writing with clarity(清晰) and fluency, Jen said.