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.

Two good friends, Simon and Jason, met with a car accident on their way home one snowy night. The next morning, Simon woke up blind. His legs were broken. The doctor, Mr. Smith, was standing by his bed, looking at him worriedly. When he saw Simon awake, he asked, " How are you feeling, Simon?” Simon smiled and said, “Not bad, doctor. Thank you very much for doing the special operation. Mr. Smith was moved by Simon. When he was leaving, Simon said, "Please don't tell Jason about it. “Well…Well…OK,” Mr. Smith replied.

Months later when Jason's wounds healed, Simon was still very sick. He couldn't see or walk. He could do nothing but stay in his wheelchair all day long. At first, Jason stayed with him for a few days. But days later, Jason thought it boring to spend time with a disabled man like Simon. So he went to see Simon less and less. He made new friends. From then on, he didn't go to visit Simon any more. Simon didn't have any family or friends except Jason. He felt very sad.

    Things went from bad to worse. Simon died a year later. When Jason came, Mr. Smith gave him a letter from Simon. In the letter Simon said, “Dear Jason, I am disabled. But I want you to be a healthy man. So I gave my eyes to you so that you can enjoy life as a healthy man. Now you have new friends.

I'm glad to see that you are as healthy and happy as usual. I'm glad you live a happy life. You are always my best friend". Simon”. When he finished reading the letter, Mr. Smith said, “I have promised that I will keep this a secret until Simon is gone. Now you know it.

    Jason stood there like a stone. Tears ran down his face.

    For Pei Shiyou, this year's Lunar New year's Eve was among the few he ha spent with his extended family.

“It's one of the benefits of starting a business in my hometown,” said Pei, who was born and raised in Hefei, Anhui province, and will soon turn 60. His wish for the Year of the Dog is to see smart glass— the product his team has been developing since 2016—go into production.

    Starting a business with a creative research team and receiving government support have given him a strong sense of pride, a feeling he says he often lacked during his 25 years working in the United States, he said.

    He was among Chinas first students to travel to the US for postgraduate stud. After that, he landed his first job at Amoco Corp and later moved to California eventually becoming head of product research and development at KLA-Tencor, a global capital equipment company in Silicon Valley. Yet Pei said he still felt unfulfilled and unsatisfied.

    “It seemed there was an invisible ceiling for me when I pursued my career in the US. I felt like it was unlikely for me to achieve any higher sense of achievement or recognition.”

    He returned to China in 2017, and nine years later established a smart-glass company in Hefei with two other US-trained engineers.

    The company's product is suitable for low-temperature, flexible smart-film manufacturing and is able to self-adjust its level of transparency based on temperature changes and sunlight conditions, according to Pei, who said it has the potential to reduce the need for air conditioning and make curtains abandoned.

    Between 2007 and 2016, Pei lived and worked in several Chinese cities. “What attracts me to Hefei is that it is easy to gather tech talents here due to the city's rapid development in recent years, and also because it has several universities,” he said. Support from the local government has been one of the best attractions that convinced Pei to locate his company in the eastern Chinese city.

    In January last year, Hefei was approved as the site of a national-level science center, the second of its kind after an earlier one was built in Shanghai. The center, now under construction, will focus on areas including information technology, energy and health.

    It's nearly exam time, so check out some of the best free apps around to help you manage the stress of exams and ensure you are studying effectively over the coming weeks.

    Exam Countdown

    This app can help to remind you how many days, hours, and minutes you have until your exam. This can help to motivate you to hit the books before it's too late.

    Block The Internet

    Are you constantly checking Facebook when you should be writing an essay? Or perhaps are you distracted by a battle in League of Legends? Download this app to get rid of online distractions by temporarily blocking Internet sites on your mobile. Simply add the websites you want to block and the period of time to block them for. Guarantee to get yourself focused on that assignment.

    CBT-i Coach

    The US Department of Veterans (老兵) Affairs developed the app, CBT-i Coach, to assist with insomnia (失眠) and help people who would like to improve their sleeping habits. It provides several key parts: information about sleep and insomnia, strategies for improving sleep, relaxation skills and a helpful sleep diary.

    Yoga

    Yoga has great health benefits both for the mind and body, and will help you to perform at your best while at university. Download a yoga app and have your own personal yoga instructor in your living room. You can choose from short or long workouts and have a qualified instructor teaching you how to do each pose. Choose from a variety of yoga routines and watch the instructional videos. Go on, stretch out those sore muscles.

Internet time tied to teen depression(抑郁) symptoms

    Spending time online is normal behaviour for teenagers. But too much Internet use by teens —or too little, for that matter —might be related to depression, a new study finds.

    The findings, reported in the journal of Pediatrics, do not mean that the Internet is to blame. For one, teens in the study who spent no time online were also at increased risk of depression symptoms. Instead, the researchers say that both heavy Internet use, and non-use, could serve as signals that a teenager is having a hard time.

    For the study, Dr. Pierre-Andre Michaud and his colleagues at the University of Lausanne, Switzerland, surveyed 7,200 individuals aged 16 to 20 about their Internet use.

    Those who were online more than two hours per day were considered "heavy" Internet users, while those online anywhere from several times per week to two hours per day were considered "regular" users.

    The teenagers also answered a number of health-related questions, including some standard questions about "depressive tendencies" that gauge(判定) how often a person feels sad or hopeless. Compared with regular Internet users, the study found, kids who were heavy users or non-users were more likely to be depressed or very depressed.

    Among male teens, heavy users and non-users were both around one-third more likely to have a high depression score, compared to "regular" users. Among girls, heavy Internet users had an 86 percent greater chance of depression, while non-users had a 46 percent greater likelihood compared to regular users.

    That was with factors like family income and any chronic health problems taken into account.

    Since teenagers typically go online to contact with friends, the researchers speculate(推测) that those who are never online may be more socially isolated.

    Happy birthday! Do birthdays really make people happy? Of course they do. Birthdays celebrate the day we were born. Besides, that extra candle on the cake suggests another year of growth and maturity (成熟)— or so we hope. We all like to imagine that we're getting wiser and not just older. Most of us enjoy seeing the miracle(奇迹) of growth in others, as well. For instance, seeing our children develop and learn new things makes us feel proud. For Americans, like people in most cultures, growing up is a wonderful process(过程). But growing old? That's a different story.

    Growing old is not exactly pleasant for people in youth-oriented(以年轻人为中心) American culture. Most Americans like to look young,act young and feel young. As the old saying goes, "You're as young as you feel." Older people joke about how many years young they are, rather than how many years old. People in some countries value the aged as a source of experience and wisdom. But Americans seem to favor those that are young, or at least "young at heart."

    Many older Americans find the "golden years" to be anything but golden. Economically, "senior citizens" often struggle just to get by. Retirement(退休) at age 65 brings a sharp decrease in personal income. Social security(安全) benefits usually cannot make up the difference. Older people may suffer from poor nutrition(营养), medical care and housing. Some even experience age discrimination. In 1987, American sociologist Pat Moore dressed up like an older person and wandered city streets. She was often treated rudely — even cheated and robbed. However, dressed as a young person, she received much more respect.

    Unfortunately, the elderly population in America is increasing fast. Why? People are living longer. Fewer babies are being born. And middle-aged "baby boomers" are rapidly entering the groups of the elderly. America may soon be a place where wrinkles(皱纹) are "in". Marketing experts are already noticing this growing group of consumers.