A new study finds that young females in one group of African chimps(黑猩猩) use sticks as dolls more than their male peers (同龄) do, often treating pieces of wood like a mother chimp caring for a baby. In human cultures around the world, girls play with dolls and pretend that the toys are babies far more than boys do.

    Chimp observations, collected over 14 years of field work with the Kanyawara chimp community in Kibale National Park in Ugandan, provide the first evidence of a nonhuman animal in the wild that exhibits sex differences in how it plays. This finding supports an argument that biology as well as society underlies boys' and girls' different toy preferences.

    Stick play occurred most commonly between ages 3 and 9. Females spent a lot more time carrying sticks than males did. Young male chimps occasionally used sticks to mimic(模仿) childcare. "Far more often, they fought with sticks, an infrequent behavior among females," say Sonya Kahlenberg of Bates College in Lewiston, Maine, and Richard Wrangham of Harvard University.

    "Biological differences between the sexes make female chimps more receptive to stick-mothering than males," says Wrangham.

    Consistent with reported cultural traditions among adult chimps, Kanyawara youngsters learned from each other to play with sticks as if caring for babies. Stick play among young chimps showed no evidence of being directly influenced by older chimps. Child-bearing females never played with sticks and thus didn't model such behavior for younger chimps.

    Young females carried sticks for anywhere from a few minutes to several hours. They often rested in nests with their sticks, sometimes playing with them much as chimp mothers play with their babies though they didn't get any form of teaching from the adults.

    Explore the possibility of using the iPad App Store in the classroom.

    App Name: Bridge Constructor/Cost: $1.99

    Bridge Constructor lets players build increasingly challenging bridges over deep valleys, canals and rivers. Stress tests reveal whether the bridge kids build can withstand continual use from cars, trucks, and more recently, super-heavy tank trucks. Players can choose from among a range of bridge-building materials such as wood, steel, cables and concrete pillars (混凝土柱). Each bridge also has a budget, and there are numerous ways to successfully complete each challenge.

App Name: Pyramid Adventure 3-D/Cost: $13.99

    The interface allows users to fly around the plateau where the pyramids and the Sphinx are located at Giza near Cairo. Interactive, three-dimensional maps let students wander around the labyrinthine tombs and passageways. Uses can examine wall paintings in detail, or view royal statues and objects with a 360-degree feature. To help explain the world of ancient Egyptians, the app offers an accompanying interactive book, specially written by world-famous Egyptologist Zahi Hawass.

    App Name: Grammar Up/Cost: $4.99

    Grammar Up is a multiple-choice quiz system for English grammar. Kids and adults can learn most quickly when playing learning games with real-time error feedback, which Grammar Up provides. The app also offers students practice tests so they can see how much they've learned. A summary is presented at the end of each test, showing the time spent, a score, and the questions answered correctly and incorrectly. The results are also e-mailable.

    The Healthy Habits Survey shows that only about one third of American seniors have correct habits. Here are some findings and expert advice.

    ⑴How many times did you brush your teeth yesterday?

    Finding: A full 33% of seniors brush their teeth only once a day.

    Step: Remove the 300 types of bacteria in your mouth each morning with a battery-operated toothbrush. Brush gently for 2 minutes, at least twice a day.

    ⑵How many times did you wash your hands or bathe yesterday?

Finding: Seniors, on average, bathe fewer than 3 days a week. And nearly 30% wash their hands only 4 times a day—half of the number which doctors recommend.

    Step: We touch our faces around 3,000 times a day-often inviting germs（病菌）to enter our mouth, nose, and eyes. Use toilet paper to avoid touching the door handle. And, most important, wash your hands often with hot running water and soap for 20 seconds.

    ⑶How often do you think about fighting germs?

    Finding: Seniors are not fighting germs as well as they should.

    Step: Do you know it is not your toilet but your kitchen sponge（海绵）that can carry more germs than anything else? To kill these germs, keep your sponge in the microwave for 10 seconds.

    One summer I was driving from my home town of Tahoe City, Calif., to New Orleans. In the middle of the desert, I came upon a young man standing by the roadside. He had his thumb out and held a gas can in his other hand. I drove right by him. There was a time in the country when you'd be considered a jerk if you passed by somebody in need. Now you are a fool for helping. With gangs, drug addicts, murderers, rapists, thieves lurking everywhere, "I don't want to get involved" has become a national motto.

    Several states later I was still thinking about the hitch­hiker. Leaving him standing in the desert did not bother me so much. What bothered me was how easily I had reached the decision. I never even lifted my foot off the accelerator.

    Does anyone stop any more? I wondered. I recalled Blanche DuBois's famous line: "I have always depended on the kindness of strangers". Could anyone rely on the kindness of strangers these days? One way to test this would be for a person to journey from coast to coast without any money, relying solely on the good will of his fellow Americans. What kind of Americans would he find? Who would feed him, shelter him, carry him down the road?

    The idea intrigued me.

    The week I turned 37, I realized that I had never taken a gamble in my life. So I decided to travel from the Pacific to the Atlantic without a penny. It would be a cashless journey through the land of the almighty dollar. I would only accept offers of rides, food and a place to rest my head. My final destination would be Cape Fear in North Carolina, a symbol of all the fears I'd have to conquer during the trip.

    I rose early on September 6, 1994, and headed for the Golden Gate Bridge with a 50­pound pack on my back and a sign displaying my destination to passing vehicles: "America".

    For six weeks I hitched 82 rides and covered 4,223 miles across 14 states. As I traveled, folks were always warning me about someplace else. In Montana they told me to watch out for the cowboys in Wyoming; in Nebraska they said people would not be as nice as in Iowa. Yet I was treated with kindness everywhere I went. I was amazed by people's readiness to help a stranger, even when it seemed to run contrary to their own best interests.

    Now, more than ever before, people are wondering what life is all about, and what it is for. Seeking material success is beginning to trouble large numbers of people around the world. They feel that the long-hours work culture to make more money to buy more things is eating up their lives, leaving them very little time or energy for family or pastimes. Many are turning to other ways of living and downshifting is one of them.

    Six percent of workers in Britain took the decision to downshift last year. One couple who downshifted is Daniel and Liz. They used to work in central London. He was a newspaper reporter and she used to work for an international bank. They would go to work by train every day from their large house in the suburbs, leaving their two children with a nanny(保姆). Most evenings Daniel wouldn't get home until eight or nine o'clock, and nearly twice a month he would have to fly to New York for meetings

    They both earned a large amount of money but began to feel that life was passing them by.

    Nowadays, they run a farm in the mountains of Wales, I always wanted to have a farm here, says Daniel, "and we took almost a year to make the decision to downshift. It's taken some getting used to, but it's been worth it. We have to think twice now about spending money in car repairs and we no longer have any holidays. However, I think it's made us stronger as a family, and the children are a lot happier."

    Liz, however, is not quite sure. "I used to enjoy my job, even though it was hard work and long hours. I'm not really a country girl, but I suppose I'm gradually getting used to looking after the animals. One thing I do like, though, is being able to see more of my children. My advice for other people wanting to do the same is not to think about it too much or you might not do it at all."