When you go to the doctor, you like to come away with a prescription．It makes you feel better to know you will get some medicine. But the doctor knows that medicine is not always needed. Sometimes all a sick person needs is some reassurance that all will be well. In such cases the doctor may prescribe a placebo.

    A placebo is a sugar pill, a harmless shot, or ail empty capsule. Even though they have no medicine in them, these things seem to make people well. The patient thinks it is medicine and begins to get better. How does this happen?

    The study of the placebo opens up new knowledge about the way the human body can heal itself. It is as if there was a doctor in each of us. The doctor will heal the body for us if we let it. But it is not yet known just how the placebo works to heal the body. Some people say it works because the human mind fools itself. These people say that if the mind is fooled into thinking it got medicine, then it will act as if it did, and the body will feel better.

    Placebos do not always work. The success of this treatment seems to rest a lot with the relationship between the patient and the doctor. If the patient has a lot of trust in the doctor and if the doctor really wants to help the patient, then the placebo is more likely to work. So in a way, the doctor is the most powerful placebo of all.

    A placebo can also have bad effects. If patients expect a bad reaction to medicine, then they will also show a bad reaction to the placebo. This would seem to show that a lot of how you react to medicine is in your mind rather than in your body. Some doctors still think that if the placebo can have bad effects it should never be used. They think there is still not enough known about it.

    The strange power of the placebo does seem to suggest that the human mind is stronger than we think it is. There are people who say you can heal your body by using your mind. And the interesting thing is that even people who swear this is not possible have been healed by a placebo．

    Teens don't understand the big fuss (小题大做). As the first generation to grow up in a wired world they hardly know a time when computers weren't around, and they eagerly catch the chance to spend hours online, chatting with friends, so what?

    But researchers nationwide are increasingly worried that teens are becoming isolated, less skillful at person-to-per son relationships, and perhaps numb to the cheatings that are so much a part of the e-mail world. "And a teen's sense of self and values may be changed in a world where personal connections can be limitless," said Shetty Turkle.

    Another researcher, Robert Kraut, said he's worried about the "opportunity costs" of so much online time for youths. He found that teens who used computers, even just a few hours a week, showed increased signs of loneliness and social isolation. "Chatting online may be better than watching television, but it's worse than hanging out with real friends," he said.

    Today's teens, however, don't see anything strange in the fact that the computer takes up a central place in their social lives. "School is busy and full of pressure. There's almost no time to just hang out," said Parker Rice, 17 "Talking online is just to catch time."

    Teens say they feel good about what they say online or taking the lime to think about a reply. Some teens admit that asking someone for a date, or breaking up, can be easier in message form, though they don't want to do so. But they insist there's no harm.

    Imagine you went to a restaurant with a date, had a burger, paid with a credit card, and left. The next time you go there, the waiter or waitress, armed with your profile data, greets you with, "Hey Joe, how are you? Mary is over there in the seat you sat in last time. Would you like to join her for dinner again?" Then you find out that your burger has been cooked and your drink is on the table. Forget the fact that you are with another date and are on a diet that doesn't include burgers. Sound a little odd? To some, it is the same with the Internet. The Nets ability to profile you through your visits to and interactions at websites provides marketers with an enormous amount of data on you--some of which you may not want them to have.

    Are you aware that almost every time you access a website you get a "cookie"? Unfortunately, it's not the Mrs.

    Reid's type. A cookie on the Internet is a computer code sent by the site to your computer--usually without your knowledge. During the entire period of time that you are at the site, the cookie is collecting information about your interaction, including where you visit, how long you stay there. How frequently you return to certain pages, and even your electronic address. Fill out a survey to collect free information or samples, and marketers know even more about you--like your name, address, and any other information you provide. While this may sound scary enough, cookies aren't even the latest in technology. A new system called I-librarian Alexa--named for the legendary third century.

    B. C. library in Alexandria, Egypt--does even more. While cookies track what you are doing at one site, Alexa collects data on all your Web activity, such as which sites you visit next, how long you stay there, whether you click on ads, etc. All this information is available to marketers, who use it to market more effectively to you. Not only do you not get paid for providing the information, you probably don't even know that you are giving it.

    Researchers continue to show the power behind our sense of smell. Recent studies have found, among other things, that the smell of foods like pizza can cause uncontrollable anger in drivers on roads.

    The review explains that smell is unique in its effects on the brain. According to Conrad King, the researcher who carried out the review, “more than any other senses, the sense of smell goes through the logical part of the brain and acts on the systems concerned with feelings. This is why the smell of baking bread can destroy the best intentions of a dieter.”

    Smell, which dictates(决定) the unbelievable complexity of food tastes, has always been the least understood of our senses. Our noses are able to detect up to 10,000 distinct smells. Our ability to smell and taste this extremely large range of smells is controlled by something like 1,000 genes (基因), which make up an amazing 3% of the human genome. Researchers Richard Axel and Linda Buck were together awarded a Nobel Prize in 2004 for their ground-breaking research on the nature of this extraordinary sense. These two scientists were the first to describe the family of 1,000 olfactory (嗅觉) genes and to explain how our olfactory system works.

    According to one study in the research review, smelling fresh pizza or even the packaging of fast foods can be enough to make drivers feel impatient with other road users. They are then more likely to speed and experience uncontrollable anger on roads. The most reasonable explanation is that these can all make drivers feel hungry, and therefore desperate to satisfy their appetites.

    In contrast, the smells of peppermint and cinnamon were shown to improve concentration levels as well as reduce drivers' impatience. Similarly, the smells of lemon and coffee appeared to promote clear thinking and mental focus.

    However, the way genes regulate smell differs from person to person. A study by researchers in Israel has identified at least 50 olfactory genes which are switched on in some people and not in others. They believe this may explain why some of us love some smells and tastes while others hate them. The Israel researchers say their study shows that nearly every human being shows a different pattern of active and inactive smell-detecting receptors.

    I must have looked deep in thought, or as deep in thought as an 11-year-old man can, when my grandmother glanced up from her weeding to ask, “You have something on your mind, don't you?”

    “Yes, I was thinking that someday I want to be an Olympic speed skating champion like my hero, Eric Haiden, I want to be a doctor like my parents and I want to help children in Africa.”

    I immediately knew I had confided in the right person when a knowing smile broke across her face. “Johann, of course! You can do anything you want to do!” she said simply. And with my grandmother's support, I set out to pursue my passions.

    14 years later, I was well ready to take hold of my first dream: becoming an Olympic champion. The Olympics in 1994 were in my home country, Norway. As I entered the Olympic stadium, I wasn't the best athlete, and many had doubts about my ability to perform well. But I had something special working for me. I had a woman in the first row who believed in me following my passions just as much as I did. For the first time ever, my grandmother was going to see me skate.

    It happened. Breaking a world record, I won the gold.

    As I stood on the podium(领奖台) that I had dreamed about my entire life, a curious question popped into my head. Why me? Why did I win, given all the other incredible competitors out there? The reason had to be more than a grandmother who shared a belief in her grandson's dream. The question led me to only one answer: because I wanted to make a difference in the world, and with all the media attention on my success, I could.

    I immediately knew what that difference had to be: hope in the lives of the children in Africa. Six months earlier, I'd been invited to Eritrea as an ambassador for Olympic Aid.

Researchers at MT created a high-tech pill that starts to vibrate(震动) once it makes contact with liquid in the user's stomach and make him or her feel full. The pill was reportedly thought up by Shriya Srinivasan, currently an assistant professor of bioengineering at Harvard University.

VIBES, short for Vibrating Ingestible BioElectronic Stimulator，was only recently made public in a study published in the Science Journal, but it is already being announced by the media as the future of weight loss. Although it has yet to be tested on humans, trials on pigs have achieved very hopeful results. After about 30 minutes of VIBES activity, pigs consumed on average almost 40 percent less food in the next half hour than they did without the smart pill. Apparently, the revolutionary device works by activating stretch receptors in the stomach, modeling the presence of food. This in turn signals the hypothalamus(下丘脑) to increase the levels of hormones that make us feel full. The vibrating stimulator, which is about the size of a vitamin pill, is powered by an encased battery and activated either by the gastric fluid(胃液) breaking down a coat around the pill, or by an incorporated timer. After producing the desired effect, the pill exits the body with other solid waste.

The good news is that it is expected to have a cost in the cents to one dollar range, and researchers say that it may eventually be possible to implant the stimulator and thus remove the need for people to constantly swallow it.

"Our study demonstrates the effectiveness of a low-cost, non-operative intervention to reduce food intake and calorie consumption. The device functions effectively in the stomach and leading to fullness," said Giovanni Traverso, co-author of the study. "The device has the potential to revolutionize options for weight loss treatment. However, future studies will need to explore the physiological effects of the device before it's available for patients."

Researchers are now exploring ways to scale up the producing of VIBES capsules which could enable clinical trials in humans.