Your New Year's plan to move more is one of the toughest to stick to, and a group of scientists working with obese(过度肥胖的) mice think they're starting to understand why

    Rather than our sedentary(久坐的) lives causing weight gain, says Alexxai Kraviz, the National Institutes of Health neuroscientist who led the study, changes in brain chemistry after we start gaining weight affect our capacity to move.

    “Obses mice can move just fine,” says Kravitz, who published the work with his team in Cell Metabolism “They just don't.”

    What Kravitz's team found is that the activity of a particular dopamine(多巴胺) receptor linked to movement goes down as mice gain weight on a high-fat diet. So the nice slow down and they move less. And when the researchers restored the activity of that dopamine receptor—DR2—the mice started moving more, even though they were still obese. The team also saw that lean mice missing the DR2 receptor acted like obese mice. This is the target, says Kravitz—restoring that dopamine receptor function. “Maybe 20 or 30 years down the road, we could do that in people,” he says.

    And there is one more thing: The scientists fed normal mice and the mice lacking DR2 the same high-fat diet. Both sets of mice gained weight at the same rate.

    Kravitz says this is important because mice lacking DR2 move less from the get-go, whereas a normal mouse takes a little time to start seeing that dopamine receptor-related loss of exercise. The ability to exercise seems to be disconnected from weight gain, he says.

    “Exercise is a healthy thing to do, but its impact on weight loss has been exaggerated,” he says. “We have to be realistic about the size of the effect of exercise on weight, as opposed to health benefits.”

    Still, before you abandon your New Year's exercise plan, keep in mind that this study was done using a high-fat diet, and not the normal calorie restriction that people maintain when they diet.

    That's a big drawback to the work, says Vicki Vieira-Potter, a University of Missouri physiologist not involved in the study.

    “They feed the mice with high-fat diet, it damages the receptor, and that decreases activity. Those who plan to lost weight should remember high-fat diet is a nice way to cause obesity in the lab, but it's not the same as the normal situation of obesity,” she says.

    Sine also says that a lot of the weight gain in the mice came after they stopped moving around, which indicates that the loss of movement did impact obesity.

    When my friend Lesa was diagnosed(诊断) with cancer, another friend and I went to the hospital to spend some time with her. We bought her a small toy and  named him Lemon－Aide. We gave Lemon－Aide to Lesa and told her he was to go with her to all of her treatments to remind her that we were thinking of her and caring about her even though we could not always be with her. When the treatments were completed, she said when someone else needed him she would pass him along.

    A few months later，much to my surprise, it was me that she passed him to. Lemon－Aide went with me to all of my treatments.

    One day while waiting for my doctor I decided we could market the idea to fight cancer. Lesa thought it was a great idea so we founded the organization that came to be known as Lemon－Aide' s Friends, Inc. We designed our organization to remind people fighting cancer that there are people who love and care about them all the time. Today we have totally 5013 volunteers. The money raised is donated to cancer patients who do not have insurance. The physicians on our Board of Advisors determine how and where our money is donated.

    Lemon－Aide is for men, women, and children of all ages and to date has been sent to 34 states and 33 countries to provide smiling support for people fighting cancer. When life gave us lemons we made Lemon－Aide, a soft smiling toy that represents love, support, and encouragement.

    In the latest romance-drama, Descendants of the Sun (《太阳的后裔》), a handsome soldier Yoo Shi-jin（柳时镇） (Song Joong-ki)(宋仲基) meets the pretty doctor Kang Mo-yeon（姜暮烟） (Song Hye-kyo)（宋慧乔） in a hospital, and he doesn't hesitate to hit on her.

    The dialogue, which takes place early in the first episode( 集）, immediately indicates that this is no ordinary South Korean drama. There's no family feud （不睦）, or love tangles, or guesses and misunderstandings. The 16-episode show is set in the fictional war-torn country of Uruk （乌鲁克）. Song Joong-ki is the leader of a special warfare command unit, while Song Hye-kyo plays a doctor who works for a humanitarian medical organization. Both are sent in the midst of disaster and disease as part of their work with UN peacekeeping troops. Both know and show clearly what they want and what they hate.

    But what stands out the most are Song's skills as a pick-up artist（撩妹技能）.

    Boldness and creativity are the key weapons in his arsenal. When Kang invites Yoo to drink wine with her, Yoo, who is not allowed to drink alcohol as a soldier, says, “There is a way” before kissing her. Forget about the “eighth-episode rule”. This kiss happens in the fourth.

    Humor also does the trick. On their first date in a cinema, Yoo says, “This is the most exciting moment of my life. The moment I am with a beautiful woman before the theater lights go out.” When Kang tries to give Yoo a hard time, Yoo jokes, “I mistook you for a beautiful woman because it's dark.”

    And actor Song Joong-ki, who just came back from two years of military service last May, makes sure he delivers his pick-up lines just right.

    “In Deep Rooted Tree (《树大根深》) and The Innocent Man (《善良的男人》), he [Song Joong-ki] showed he had the steel to play fearless and heartless men – that he could be taken seriously as an actor, despite his pretty face. In Descendants, he hits the emotional core of every scene, whether he has to be bold and amorous, guarded and mysterious, or sad,” said critic Foong Woei Wan in The Straits Times.

    A long time ago, soldiers fought wars on foot. Then they began to ride horses to battle. Until the invention of the stirrups (马蹬), though, men could not fight well with swords or spears while on horseback.

    Without stirrups, soldiers had no place to put their feet. They could not stand up to use their swords without falling off their horses. They could throw spears only with the force of their arms.

    Using stirrups, a soldier could stand up in his saddle (鞍). He could put a spear under the top part of his arm and charge with the force of his horse. He could use force when fighting with a sword. And he could win most fights against soldiers who did not use stirrups.

    The first stirrups were made in India. Because the weather was warm, people did not wear shoes. The Indian stirrup was made of rope. It fit around the big toes. Later, the Chinese made a foot stirrup of wood. Because the Chinese lived in a colder country, the stirrup had to fit around shoes. Still later, around A. D. 700, soldiers in Asia used strong iron foot stirrups.

    Physics is a different world now. Will there ever be another Einstein?

    Scientists say a new Einstein will appear, but it may take a long time. After all, more than 200 years separated Einstein from his nearest rival (对手) , Isaac Newton. Many physicists say the next Einstein hasn't been born yet, or is only a baby now. That's because the searching for a unified(统一的) theory that would explain all the forces of nature has pushed current mathematics to its limits. New math must be created before the problem can be solved.

    But researchers say there are many other factors working against another Einstein appearing anytime soon. For one thing, physics is quite a different field today. In Einstein's day, there were a few thousand physicists worldwide, and fewer theoreticians. Education is different, too. One extremely important aspect of Einstein's training that failed to be considered is the philosophy he read as a teenager. It taught him how to think theoretically about space and time.

    And he was a skilled musician. The interplay between music and math is well known. Einstein would fiercely play his violin as a way to think through a knotty physics problem.

    Today, universities have produced millions of physicists. There aren't many jobs in science for them, so they go to Wall Street and Silicon Valley to apply their analytical skills to more practical and rewarding efforts.

    Besides, those who stay in science don't work alone. It's very difficult to imagine an independent person like Einstein ever tolerating this.

    Summer holidays are coming. Here are two posters for members of English Club in the  schoolyard：