Exercise may help to safeguard the mind against depression through previously unknown effects on working muscles, according to a new study involving mice.

    Mental health experts have long been aware that even mild, repeated stress can contribute to the development of depression and other mood disorders in animals and people. Scientists have also known that exercise seems to cushion against depression. But precisely how exercise, a physical activity can lessen someone's risk for depression, a mood state, has been mysterious. So for the new study, researchers at the Karolinska Institute in Stockholm studied the brains and behavior of mice in a complicated and novel fashion.

    We can't ask mice if they are feeling cheerful or in low spirits. Instead, researchers have pictured certain behaviors that indicate depression in mice. If animals lose weight, stop seeking out a sugar solution when it's available — because, probably, they no longer experience normal pleasures — or give up trying to escape from the cold-water zone just freeze in place, they are categorized as depressed. And in the new experiment, after five weeks of frequent but low-level stress, such as being lightly shocked, mice displayed exactly those behaviors. They became depressed.

    The scientists could then have tested whether exercise blunts (延缓) the risk of developing depression after stress by having mice run first. But, frankly, from earlier research, they wanted to know how, so they bred pre-exercised mice. A wealth of earlier research by these scientists and others had shown that aerobic exercise, in both mice and people, increases the production within muscles of an enzyme (酶) called PGC-1alpha. The Karolinska scientists suspected that this enzyme somehow creates conditions within the body that protect the brain against depression. Then, the scientists exposed the animals, which without exercising, were in high levels of PGC-1alpha to five weeks of mild stress. The mice responded with slight symptoms of worry. But they did not develop depression. They continued to seek out sugar and fought to get out of the cold-water zone. Their high levels of PGC-1alpha appeared to make them depression-resistant. Finally, to ensure that these findings are relevant to people, the researchers had a group of adult volunteers complete three weeks of frequent endurance training, consisting of 40 to 50 minutes of moderate cycling or jogging. The scientists conducted muscle biopsies (活体检查) before and after the program and found that by the end of the three weeks, the volunteers' muscle cells contained substantially more PGC-1alpha than at the study's start. The finding of these results, in the simplest terms, is that “you reduce the risk of getting depression when you exercise,” said Maria Lindskog, a researcher at the Karolinska Institute.

    If you could have one superpower, What would it be ?

    Dreaming about whether you would want to read minds , see through walls , or have superhuman strength may sound silly , but it actually gets to the heart of what really matters in your life 1

    Every day in our work , we are inspired by the people we meet doing extraordinary things to improve the world.

    They have a different kind of superpower that all of us possess : the power to make a difference in the lives of others .

    We're not saying that everyone needs to contribute their lives to the poor . Your lives are busy enough doing homework , playing sports , making friends , seeking after your dreams . But we do think that you can live a more powerful life when you devote some of your time and energy to something much larger than yourself . Find an issue you are interested in and learn more . Volunteer or , if you can , contribute a little money to a cause . Whatever you do , don't be a bystander . Get involved . You may have the opportunity to make your biggest difference when you're older . But why not start now ?

    Our own experience working together on health , development , and energy the last twenty years has been one of the most rewarding parts of our lives . It has changed who we are and continues to fuel our optimism about how much the lives of the poorest people will improve in the years ahead .

    We are naturally drawn to friends and colleagues with familiar voices, scientists have found. People prefer those who have a similar accent, intonation and tone of voice to themselves, they discovered.

    Previous research has focused on how male or female a voice sounds. Men with deeper voices and women with slightly higher voices were thought to sound more attractive, because they suggest a bigger or a smaller body.

    But the new study, published by a linguistics expert in Canada, suggests there is a more complex mechanism (机制) at play. Dr Molly Babel, from the University of British Columbia in Canada, said, “The voice is an amazingly flexible tool that we use to construct our identity. Very few things in our voices are changeless, so we felt that our preferences had to be about more than a person's shape and size.”

    She recorded 30 volunteers' voices and asked each to rate the others' attractiveness on a range from one to nine. Each participant was from western America, with similar accents. The people we assessed were all in the same dialect group, but they showed that dialect to different degrees.

     “We seem to like people who sound like we sound, and we like people who fit within what we know,” Dr Babel said. She also found that breathy voices in women—typified by the famous American actress Marilyn Monroe-were seen as more attractive.

    The breathy tone, caused by younger and thinner vocal cords (声带), implied youthfulness and health. A creaky (咯吱作响的) voice, suggesting a person has a cold, is tired or smokes, was seen as unattractive. The participants preferred men who spoke with a shorter average word length and deeper voices.

    Love to sink into your chairs and relax when you get to school. Then you will not be happy to hear that schools all over the world are seriously considering exchanging traditional desks for ones with no seats at all — Yes, that means you will be encouraged to stand through those already too long math and science lessons! Why would anyone even think of putting kids to such cruelty. Experts say it improves their health and helps fight obesity. While that may seem a little far-fetched (牵强的), the officials at the few schools around the world seem to agree.

    Among them are educators from the College Station Independent School District in Texas, who recently completed a week-long experiment involving 480 students across three elementary schools. The 374 kids that agreed to participate in the study were provided a device that helped record step count and calorie consumption over the entire period.

    All 25 teachers involved in the study reported that students appeared to be more alert and concentrate better, when allowed to stand. The one thing that did surprise the researchers was that younger kids were more willing to stay standing than kids in higher grades. They believe this may have something to do with the fact that after years of being asked to “sit still”, older kids have a harder time adjusting to this unexpected freedom.

    American schools are not the only ones reporting success with stand-up desks. Four schools in Perth, Australia, which have been testing them since October 2013, have seen similar results. In May 2014, Grove House Primary School in West Yorkshire, became Europe's first test one, with a seven-week trial that involved the use of desks made by Ergotron in their fifth-grade classrooms. While official results are not out yet, early reactions from both teachers and students, have been extremely encouraging.

    The findings of these studies and others done previously, all seem to mean that allowing kids to move around in classrooms is a win-win for students and teachers — it helps kids get healthier and provides educators with a more attentive audience.

    It is good to get in touch with your inner child from time to time, and obviously some people are willing to pay big money for the chance to do so in a proper environment. A Brooklyn-based adult preschool is charging customers between $333 and $999 for the chance to act like a kid again.

    At Preschool Mastermind in New York adults get to participate in show—and—tell, arts—and—crafts such as finger paint, games like musical chairs and even take naps. The month-long course also has class picture day where the adults are expected to have a field trip and a parent day.

    30-year-old Michelle Joni Lapidos, the brain behind the adult preschool, studied childhood education and has always wanted to be a preschool teacher. She's always on the lookout for new ways to get people in touch with the freedom of childhood. A friend encouraged her to start the mastermind course instead.

    According to Candice, her blogger friend, Preschool Mastermind gives adults a chance to relearn and master the things that they failed to understand as children. "I realized all the significances of what we learn in preschool," said founder Michelle Joni, "People come here and get in touch with their inner child. It's magical. We are bringing ourselves back to another place, another time with ourselves when we are more believing in ourselves, more confident and ready to take on the world."

    "One person's here because they want to learn not to be so serious." Michelle said. "Another's here to learn to be more confident." She explained that most of the classes were planned. However, Joni added that while the planned activities were fun, it was often the spontaneous(自发的)moments that attracted students. "It's the things you don't plan for, the sharing between friends and learning from each other."

    Christa Marie Eastburn has added a new name to the list of people she sends Father's Day cards to—a father she grew up never knowing. In North Kansas City, the 57-year-old woman thought her father died 54 years ago, but this summer she learned he is alive. "I have a real father to send a card to this time, "she told the newspaper last week. “But I still don't have everything that goes with it—like the memories.” Her parents, Karl Beinfohr and Ingeborg Mueller, got married in Germany in the 1940s when World War II was on and a year later Marie was born—a daughter who grew up thinking her father, a German soldier, died in the war.

    This year, Eastburn found and got in touch with relatives in Germany, hoping they could tell her about her father. One day, a letter arrived in her mailbox.

    "All these years of quietness, "Beinfohr wrote, "I don't know what you have lived through. The news that she had a father who lived an ocean away brought tears to Eastburn's eyes.

    Eastburn and her father began writing to each other. In his letters, Beinfohr tried to explain the years lost. Finally, last month, Eastburn went to Germany to meet her father. They looked through old photos. Beinfohr showed his daughter one of her old toys he had kept.