Parents often think that time spent with their kids will gradually decrease in adolescence. But a new study suggests that while teens try to avoid spending a lot of time together with their parents, private parent-child meetings may actually increase in their early adolescent years. And that may raise a teenager's self-esteem (自尊) and social confidence, especially if it is the time that spent with Dad, the researchers added. The researchers created a long-term study in which they invited families in 16 school districts in central Pennsylvania to participate. In each family, a teenager, a younger sibling (兄弟姐妹), their mother and their father were interviewed at home and then asked about their activities and self-worth five times over a period of seven years.

    The study authors were surprised to discover that when fathers spent more time alone with their teenagers, the kids reported they felt better about themselves. Something about the father's role in the family seemed to improve self-esteem among the teenagers in the study, said study co-author Susan McHale, a professor of human development at Pennsylvania State University.

    “Time with Dad often involves joking, teasing, and other playful interactions. Fathers, compared to mothers, were more involved in leisure activities and had more peer-like interactions with their children, which is crucial for youth social development,” the study showed. But Marta Flaum, a psychologist in Chappaqua, New York, said, “How these findings reflect the real world is a real question. The sample in the study is so small and so unrepresentative of most families in the country today that I'm not sure how much we can generalize from it. In my community in Westchester County, I don't see parents and teenagers spend much time together at all. Parents are often working so hard and have less time to be together with their kids.”

    However, Flaum encourages parents to make time for their kids no matter how much work they have to do. “Research like this reminds us of how important it is. The time we have with them is so short,” she said.

    Before the invention of hair dryer,vacuum cleaners were being used for the purpose of drying and styling hair. The early vacuum cleaners could draw in air as well as blowing air.So,towards the end of the 19^th century,women used to dry their hair by using a vacuum cleaner.

    In 1890,a French salon owner Alexander F.Godefroy invented the first hair dryer.It blew warm air.However,it was not widely used,mainly because of its large size.

    The first convenient hand-held hair dryer used at home came up in 1920.It weighed over 2 lbs.However,it only produced 100 watts of power,which was not enough to dry the hair.After almost ten years came the gas-heated dryers that were widely used in barber shops.However,these dryers produced heat that was harmful to hair and the air from them made people sick,so they were soon gone.

    Around the 1940s and 1950s,the helmet（头盔）style electric dryers came into being.Curly hairstyles were popular during that time.Therefore,women used curlers and sat under the dryers to set their curls.Later,the curly style began to drop,and so did the popularity of the helmet style electric dryer.

    In the late 1950s,the first workable hair dryer was made.It had a hand-held dryer.It used only 300-400 watts. Ever since the 1950s,hand-held dryers have experienced many changes,in order to become quieter,lighter and smaller.However,how it works largely remains the same.The modem technology has made improvements to the hair dryer,reducing the heat damage to a person's hair.For producing shinier,smoother and healthier hair,dryers have been included with negative ion（负离子）technology that dries hair faster and with less heat.

    Anyone who has ever played the game of Tetris (俄罗斯方块) knows the game's surreal ability to spill into real life. After you shut off the game, you still see those Tetris blocks falling in your mind. You're grocery shopping and find yourself thinking about rearranging items on grocery shelves. Your mind continues to play the game, even when you're physically not.

    Robert Stickgold, a Harvard professor, noticed something similar after a day hiking a mountain. That night, he dreamt he was still going through the motions of mountain hiking. Curious about this, he tried something: he got a group of college students of various skill levels to play Tetris and let them sleep in the Harvard sleep lab.

    Over 60% of the students, including those who suffered from amnesia (健忘症), reported dreams of images of Tetris pieces falling, rotating (旋转), and fitting together. Interestingly, half the Tetris expert students reported such Tetris dreams, while 75% of the beginners did.

    A study found that playing Tetris can grow your brain and make it more efficient. Adolescent girls played the game for an average of 1.5 hours a week over three months. The cerebral cortex (大脑皮层) of the girls grew thicker, while brain activity in other areas decreased. Richard Haier, who had found that there was a "Tetris learning effect", in which the brain consumed less energy as mastery of the game rose, concluded, "The brain is learning which areas not to use."

    Haier's study showed that as the girls practiced playing the game, nerve cells made connections, communicating through synapses (a synapse is a connection between two nerve cells). When you learn something, you change those connections. Every time you reactivate(激活) a circuit, synaptic efficiency increases, and connections become more durable and easier to reactivate. Stickgold says sleep plays a role in this memory process.

    So to sum up, whenever you do specific tasks over and over again, they take up less of your brain power over time. And that's pretty amazing.

    Recent summer temperatures in parts of Australia were high enough to melt asphalt. As global warming speeds up the heat and climatic events increase, many plants may be unable to cope. But at least one species of eucalyptus tree can resist extreme heat by continuing to “sweat” when other essential processes stop, a new study finds.

    As plants change sunlight into food, or photosynthesize (光合作用), they absorb carbon dioxide through pores on their leaves. These pores also release water via transpiration(蒸腾), which circulates nutrients through the plant and helps cool it by evaporation(蒸发). But exceptionally high temperatures are known to greatly reduce photosynthesis—and most existing plant models suggest this should also decrease transpiration, leaving trees in danger of fatally overheating. Because it is difficult for scientists to control and vary trees' conditions in their natural environment, little is known about how individual species handle this situation.

    Ecologist John Drake of the S.U.N.Y. College of Environmental Science and Forestry and his colleagues grew a dozen Parramatta red gum (Eucalyptus parramattensis) trees in large, climate-controlled plastic pods that separated the trees from the surrounding forest for a year in Richmond, Australia. Six of the trees were grown at surrounding air temperatures and six at temperatures three degrees Celsius higher. The researchers withheld (扣留) water from the surface soil of all 12 trees for a month to imitate a mild dry spell, then induced a four-day “extreme” heat wave: They raised the maximum temperatures in half of the pods（three with surrounding temperatures and three of the warmer ones）— to 44 degrees ℃.

    Photosynthesis ground to a near halt in the trees facing the artificial heat wave. But to the researchers' surprise, these trees continued to transpire at close-to-normal levels, effectively cooling themselves and their surroundings. The trees grown in warmer conditions coped just as well as the others, and photosynthesis rates bounced back to normal after the heat wave passed, Drake and his colleagues reported online in Global Change Biology.

    The researchers think the Parramatta red gums were able to effectively sweat — even without photosynthesis — because they are particularly good at tapping into water deep in the soil. But if a heat wave and a severe drought (干旱) were to hit at the same time and the groundwater was exhausted, the trees may not be so lucky, Drake says.

    Other scientists call the finding encouraging. “It's definitely good news,” says Trevor Keenan, an ecologist at Lawrence Berkeley National Laboratory, who was not part of the study. “It would be very interesting to know how this translates to other species,” he adds. Drake hopes to conduct similar experiments with trees common in North America.

    Shyness May Be Partly Inherited(遗传)

    About 92 million Americans are shy, and according to recent research about half of them inherited the trait.

    The studies were discussed at the American Psychological Convention.

    One study, by Harvard University, was of babies 21- 48 months old. It concluded that these babies had a high heart rate when shown unfamiliar people or different toys.

    Although shyness is not new, it has only recently become of interest to researchers. The first study on the genetic connection was in 1979.

    According to Warren Jones of the University of Tulsa, social relations these days are more complex. "With less ritual(仪式) and more complex situations," he said, "shyness is a national concern."

    Not all shy people are anxious and fearful, according to another study. Evidence shows that only half of shy people are tense, worried, and fearful in social situations.

    Many men use shyness as an excuse for failing in social situations, according to C.R. Snyder of the University of Kansas. "This is not true of females. Perhaps,

    American men are pressured to be assertive(自信的) and successful. So they would rather say they're shy than admit they're incompetent."

    Shy people may do very well socially after the first meeting with someone. In fact, shy people tend to be more stable.

    The psychologists said shyness seems to be cultural. Japan has the highest rating. China and Israel have the lowest rating. The United States rated in the middle.

    In Europe, there is no escape for those who do not appreciate art and architecture(建筑). It is a heaven for people who want to feel like they have been transported to famous historical time periods from America. For me, Europe was a complete contrast from America. London and France had a more royal feel than New York, and Rome felt more ancient. I wasn't just on a different continent; it felt like I was in a different century.

    My parents and I visited London, Paris and Rome this summer in celebration of the end of my high school experience. It was supposed to be a break from a life as busy as a bee in New York, the constant stress, the crowded subway rides, and the weary body that had accompanied me for the last four years. It was an opportunity to appreciate Europe the way I couldn't do it just by reading history books.

    My favorite parts of London were the Tower of London and the Churchill War Rooms. As a site of past executions(刑场), the Tower of London displayed punishing devices from the 16^th and 17^th century and told stories of various members of the royal family who had ever been imprisoned in the tower, some even imprisoned by their own family members when they were seen as a threat to the crown. Besides that, I also got to see the royal family's crown jewels, amazingly beautiful.

    The Churchchill War Rooms, though very different from the Tower of London, were also spellbinding from a historic perspective. I am not a history fan, but I enjoy museums, and I took fancy in the Churchchill Museum inside the War Rooms that detailed the events of Churchchill's life and World War II. Everything I saw in it built up his life from his childhood to his last years, creating a three-dimensional Churchchill in my mind who was a person just like myself. He longed for more, he made mistakes, he experienced loneliness and sadness. But he had also done some remarkable things like uniting Britain during World War II.

    Our rewarding trip ended in Rome a couple of days later.