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.

    Jaden Hayes first lost his dad when he was four and then last month his mom died unexpectedly in her sleep.

    “I tried and I tried to get her awake—I couldn't,” said Jaden.

    Jaden is understandably heartbroken. But there's another side to his sadness. When he first made public a few weeks ago he told his aunt, and now guardian, Barbara DiCola, that he was sick of seeing everyone was sad all the time. And he had a plan to fix it. He asked his aunt Barbara to buy a lot of little toys and bring him to downtown Savannah, so he could give them away.

    “I'm trying to make people smile,” said Jaden. He gave his toys to people who weren't smiling and then turned their day around. He has gone out on four different occasions now and he is always successful, though sometimes he doesn't get exactly the reaction he was hoping for.

    It's just so unexpected to some people that a six-year-old child would give away a toy— expecting nothing in return—except a smile. Of course he is paid beautifully in hugs and his aunt says the reactions have done wonders for Jaden, who will then feel joyful.

    “But I'm still sad that my mom died,” Jaden said.

    This is of course not only a fix, but the smiles he has made so far—nearly 500 at last count—Jaden has clearly found a purpose.

    “I'm counting on it to be 33, 000,” said Jaden.

    When asked if he thought he could make that goal, he answered, “I think I can.”

    As we all know, there are plenty of different parks to visit in the UK. All theme parks in Britain have cafes, restaurants, picnic areas and gift shops, so you'll still have plenty to see and do when you and the kids have been on enough rides. There are usually smaller "funfair" rides and games as well, so younger children won't get bored. Several theme parks also have other attractions next to them, e. g. water parks often open all year round, unlike the theme parks.

    Whenever you are in Britain, there's likely to be a theme park within one or two hours' drive, bus ride or train journey. Several theme parks even have accommodation(膳宿)so you can stay for a day for two if you want to make a trip into a short holiday.

    Prices for UK theme parks vary considerably; some have an entrance price which allows you to go on all the rides, while in others you have to pay for every ride individually. It can also make a difference whether you go during peak time or not. For example, tickets always cost more during school holidays and weekends than they do during the weekdays.

    Theme parks always get very busy during the summer months, so if you don't like crowds it's usually a good idea to go earlier or later in the year!

    If you're thinking of visiting a UK theme park, it's worth having a look for special offers on tickets. Products such as chocolate bars and cereals sometimes have "buy one get one free" offers on theme park tickets, so keep a look out in shops and supermarkets.

    I believe children have a very pure sense of humor. Well, I would like to share my experiences with you.

    The other day when I was out with a friend and her daughter Jane at a restaurant, Jane ordered an apple dessert, which was the most attractive dish in that restaurant. However, when she had a bite of the pie, she shouted loudly, "Mom, why does it look good but tastes like rubber?" My friend was uneasy. Then the waiter gave us another dish.

    A child can say funny things. I was at a friend's home for tea and her son, Mark, wanted her to get up. His mom replied, "I can't, because my foot has fallen asleep now." Little Mark then sang a song and asked, "Mom, will it wake up now?" We laughed together.

    The other day we were having an interesting conversation over lunch and my friend, an animal activist (积极分子) , was arguing with another group member. Her son Tommy suddenly stood up, “Mom, people should never be allowed to shoot extinct animals!” That was funny and the child did manage to turn the argument into a pleasant conversation.

    Well, children sometimes really surprise us. I think we can have a lot to learn from them. They can help us understand the simple world through their eyes.

Scientists at the Department of Energy's Lawrence Berkeley National Laboratory and the California Institute of Technology have-in just two years-nearly doubled the number of materials known to have potential for use in solar fuels.

They did so by developing a process that promises to speed the discovery of commercially viable (商业可行性) generation of solar fuels that could replace coal, oil, and other fossil fuels.

Solar fuels, a dream of clean-energy research, are created using only sunlight, water, and carbon dioxide. Researchers are exploring a range of possible target fuels, but one possibility is to produce hydrogen by splitting water.

Each water molecule (分子) consists of one oxygen atom and two hydrogen atoms. The hydrogen atoms are extracted, and then can be reunited to create highly flammable hydrogen gas or combined with CO 2 to create hydrocarbon fuels, creating a plentiful and renewable energy source. The problem, however, is that water molecules do not simply break down when sunlight shines on them-if they did, the oceans would not cover most of the planet. They need a little help from a solar-powered catalyst (催化剂).

To create practical solar fuels, scientists have been trying to develop low-cost and efficient materials that perform the necessary chemistry using only visible light as an energy source.

A new method was developed through a partnership between the Joint Center for Artificial Photosynthesis (JCAP) and Berkeley Lab's Materials Project, using resources at the Molecular Foundry and the National Energy Research Scientific Computing Center (NERSCC). JCAP focused on developing a cost-effective method of turning sunlight, water, and carbon dioxide into fuel. It is led by Caltech with Berkeley Lab as a major partner. The Materials Project is a program based at Berkeley Lab that aims to remove the guesswork from materials design in a variety of applications.

"What is particularly significant about this study, which combines experiment and theory, is that in addition to identifying several new compounds for solar fuel applications, we can also learn something new about the basic electronic structure of the materials themselves." says Neaton, the director of the Molecular Foundry.

Do you like doing exercise? Do you want to know the benefits from the exercise? Let's learn something about exercise. 

Exercise is any action that gets you moving. You can run, ride a bike, swim, jump rope or row a boat. It's all good for you! 

There are three kinds of exercise. One is stretching(拉伸). You may do this in dance, yoga or at the gym. When you stretch, you keep your muscles(肌肉)bendable(可弯曲的). 

Aerobic exercise(有氧运动)makes your heart beat fast. You get this kind of exercise when you walk or run. Your heart beats fast when you swim, too. 

The last kind of exercise makes your muscles strong. You build strong muscles when you lift weights. When you sprint or run fast, you make your muscles strong, too. 

You get exercise when you play tag and hide and seek. Leapfrog and ball games are also good to do. So go outside and have fun! If you keep on doing exercise, you will know the more exercise you do, the healthier and happier you will be.