As we know, DNA testing is very useful for crime fighting. But now crime fighters could have a new tool at hand. Researchers have developed a cutting-edge (前沿的) technique to identify human hair. Their test is quicker than DNA analysis techniques currently used by the police.

    DNA testing is commonly used for identification because DNA is unique to each individual. However, environmental and chemical processes can degrade(降解) DNA, limiting its usefulness over time. Protein (蛋白质) in hair, on the other hand, is more stable than DNA but can also have variations (变异体) that may be unique to the individual.

    “Our analysis process can be used universally, ”says Ms. Huang, “One of our samples even included dyed hair and the test was 100 per cent accurate. The test was able to distinguish East Asians, Caucasians and South Asians.”

    Dr. Beauchemin says she has got in touch with law enforcement agencies about using the new technology. She is also planning to collect more hair samples and continue her research with a goal of finding where exactly in the world hair sample is from, to look for more races and determine specific age.

    “We are in a very similar place with protein-based identification to where DNA testing was during the early days of development,” said chemist Brad Hart. “This method will be a game-changer, and while we've made a lot of progress toward improving it, there are steps to go before this new technique is able to reach its full potential.”

    Last summer, as part of my high school graduation project, I volunteered at Saunders House nursing home .I choose this experience because it was something that I had never done before and I wanted to lend a helping hand．At first it was challenging because I was extremely shy. My goal in volunteering was to bring a smile to the residents（住客） by doing different activities from word games to playing chess. I feel as if I had accomplished that goal.

    At the nursing home, I did a lot of different activities with the residents ranging from Jeopardy to Wheel of Fortune. One of my favorites was a word game where I would write a ten -letter word on the board and the residents would try to come up with as many smaller words as possible. I could tell that it was one of their favorite games because they always seemed to be so enthusiastic when they played．I also transported residents to and from their rooms when they needed help; and whenever it was a nice day out, I would take them outside to get some fresh air and relax. On Saturday mornings, I would deliver the newspaper to the residents and on Sundays, I assisted with morning church services.

    The most unforgettable part of this experience was when I had one-on-one conversations with the residents. It was incredible how many great stories they had to tell. Their stories were so interesting and the experience was unforgettable for me .

    My husband and I wanted desperately the instant transformation from typical consumers to eco-conscious people. We switched our light bulbs to CFL(compact fluorescent light) bulbs to conserve energy. We went about the house turning off lights and unplugging appliances that weren't in use. But the rate of global warming exceeded our snail's pace conversion to greenhood. So I pressed onward.

    I decided to put veganism(素食主义) at the top of our agenda. Vegans refuse any animal flesh or commercial goods made from any animal byproducts such as milk or fats. All the family applauded this option except for my husband. Some kind of animal needed to sacrifice its dear life for his meal or it was his dinner. I cooked up a storm, struggling to prepare nutritious meals dominated by not-so-obvious vegan dishes like bean burritos and high-fiber vegetable stir-fry. It took a few days before he realized that he hadn't been eating any meat.

    "I feel like eating beef." he announced. So that night, I took full advantage of a zucchini (一种南瓜), cut it into chunky(粗大的) pieces and cooked them. Then I covered them with spices. My beef-starved husband had some and a curious look crossed his face.

    "Where's the beef?"

    "Living peacefully somewhere on an open plain where it belongs."

    "I knew it" he murmured. "You've surely made great contributions to the boom in cattle." His taste buds were developed completely around the flavor of every kind of animal: cattle, pigs, deer, lamb, chickens and ducks. Converting him was like feeding grass to a lion.

    I'm all for preserving our planet, but what good would it do to save the earth for tomorrow's generation if today's died of starvation? The next day, we went out for burgers. I was very careful to place the paper bag into our recycling bin.

    Summer's here and it won't be long before school-aged kids across America start complaining that they're tired of riding their bikes, playing at the park, swimming in the pool...and all the other awesome activities their parents hoped would keep them pleasant for the next 10 weeks. Well, if it's any comfort, such rapid boredom could suggest that the kids have amazing powers of memory. A new study shows that the better your short-term memory is, the faster you fed sated (过饱的）and decide you've had enough.

    "Though satiation can be physical, like when you feel full after eating too much, we were interested in the psychological (心理学的）side of satiation. Like when you're just tired of something," Noelle Nelson, assistant professor of marketing and consumer behavior. She and her colleague Joseph Redden at the University of Minnesota tried to think outside the lunch box." Something that was interesting to me is that some people get tired of same things at very different speeds. So if you think about pop songs on the radio, some people must still be enjoying them and requesting them even after hearing them a lot. But a lot of other people are really sick of those same songs."

    The difference, the researchers thought, might have to do with memories of past experiences. For example, studies show that people push away from the dinner table sooner when they're asked to describe in detail what they ate earlier for lunch.

    So the researchers tested the memory capacity (能力） of college students, The students then viewed a repeating series of three classic paintings…like The Starry Night, American Gothic, and The Scream...or listened and re-listened to a series of three pop songs...or three pieces of classical music. Throughout the test, the students were asked to rate （定等级） their experience from zero to tan. And the better a participant scored in the memory test, the faster they got bored." We found that people with larger capacities remembered more about the music or art, which led to them getting tired of the music or art more quickly. So remembering more details actually made the students feel like they'd experienced the music or art more often."

    The findings suggest that marketers could control our desire for their products by figuring out ways to keep us from fully remembering our experiences. We could also trick ourselves into eating less junk food by putting ourselves in the memory of a previous (之前的) snack. As for kids easily bored, just tell them to forget about it—it might help them have more fun.

Gene technology to benefit people

    Among all the fast growing science and technology, the research of human genes, or biological engineering as people call it, is drawing more and more attention now. Sometimes it is a hot topic discussed by people.

    The greatest thing that gene technology can do is to cure serious diseases that doctors at present can almost do nothing with, such as cancer and heart disease. Every year, millions of people are murdered by these two killers. And to date, doctors have not found an effective way to cure them. But if the gene technology is applied, not only these two diseases can be cured completely, bringing happiness and more living days to the patients, but also the great amount of money people spend on curing their diseases can be saved, therefore it benefits the economy as well. In addition, human life span(寿命) can be prolonged.

    Gene technology can help people to give birth to more healthy and clever children. Some families, with the English imperial(皇室) family being a good example, have hereditary(遗传的) diseases. This means their children will for sure have the family disease, which is a great trouble for these families. In the past, doctors could do nothing about hereditary diseases. But gene technology can solve this problem perfectly. The scientist just need to find the wrong gene and correct it and a healthy child will be born.

    Some people are worrying that the gene research can be used to manufacture human beings in large quantities. In the past few years, scientists have succeeded in cloning a sheep; therefore these people predict that human babies would soon be cloned. But I believe cloned babies will not come out in large quantities, for most couples in the world can have babies in very normal way. Of course, the governments must take care to control gene technology.

    Physical education, or PE, isn't required for all high school students. In some schools, it isn't offered for some different reasons. But should high school students have physical education? The answer is certainly "yes".

    Today many people don't do sports. But as is known to all, doing sports is very important for an adult. Teaching teens the importance of a healthy lifestyle and making fitness plans now can help teens put exercise in the first place as an adult.

    High school isn't that easy. Many students are under a lot of stress. Stress can be harmful to a student's studies and life. Doing sports can help them deal with stress better, helping them live a happier life at school.

    The American Heart Association says that 10 million kids and teens suffer from obesity (肥胖症). Teens should get 60 minutes of physical activity per day to control their weight and to help their bones get stronger. The increase in activities that don't get teens to move around, such as video games and computer activities, means many teens don't get their required exercise. PE classes act as a public health measure to encourage physical activities and help teens have healthy weights.

    Not doing sports increases teens' risk of developing many diseases. An active lifestyle offers a good way of protection from these health problems. As much as 75 percent of health-care spending goes toward treating medical conditions that can be hindered by lifestyle changes, according to the American College of Sports Medicine.

    According to the President's Council on Fitness, Sports and Nutrition (PCFSN), students who performed five hours of physical activity each week improved their academic (学业的) performance. Students from programs with no physical activity, who used the extra time for classroom study, did not perform better on tests than those who gave up some study time in support of physical education.