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.

    Every city, in fact, can be felt by its warmth-not in terms of its natural climate but its human touch.

    About twenty years ago, I arrived in Australia. Searching for a place in a map in the street, I was approached by an elderly man who asked “How are you? Are you lost? How can I help you?”, which really impressed and warmed me. Another time, as I was pushing my bike on the sidewalk one night, a young lady shouted to me: “Carry me please” and then jumped onto my bicycle. While we had a little chat, she got where she wanted and hopped off my bike with “Thanks, bye!” At that moment, I had a sense as much of pleasant surprise as of “being trusted”.

    Still in Australia, two of my friends decided to hitch（搭便车）their way to Sydney in order to save money. A young driver stopped, and luckily he was also going to Sydney, so he let them in and even allowed them to drive while he went to sleep on the back seat. About eight hours later, they arrived and he woke up. Saying thanks to each other, they went their separate ways.

    In my opinion, no matter how developed and advanced it is, if in general a place presents itself with a cold and indifferent（冷漠的）face to people, especially to strangers, even keeping them highly alert（警惕的）not to be cheated all the time, can perhaps hardly be classified as a land of civilization（文明）. In a sense, the attitude towards strangers that the people have in the city mirrors its warmth.

    The year 3700, Earth is far too hot for any human to call it home. On this planet at least, man is nothing more than a memory--if there is anything left to remember the "wise man". But what about our wisdom--will any of it survive us?

    The conventional answer is no. Knowledge requires a knower, and there will be no knowing minds around then. But if information survives, perhaps in books or hard drives, maybe the knowledge isn't quite dead but dormant(休眠), ready to become alive with the help of other minds that develop over time or come to visit Earth in the distant future.

    At first sight, that seems to be reasonable: after all, we have done similar things with past knowledge. For example, we saved an ancient computer from a ship destroyed at sea off the southern coast of Greece, and succeeded in finding the meaning of Egyptian hieroglyphics(象形文字). Careful work can bring previously lost wisdom back to life.

    However, the key point is that there is a certain cultural continuity with those ancient times that allows us to reason and make progress in the dark: we know we are dealing with the legacy(遗产)of other humans. Without that link, the survival of objects and raw data doesn't guarantee the survival of knowledge. And a lack of continuity in language with any future intelligence would be a barrier. Knowledge is closely connected with language. When a language dies out, we can lose systems of reasoning that they contain. If that's lost, then it can't be recovered.

    All this means that other minds might not be able to fully make human knowledge alive when we are gone. It is better to concentrate on not dying out in the first place.

    A survey has shown that what you do on a plane can be determined by which nationality is listed on your passport.

    According to the results of an international passenger survey, Australians are the biggest drinkers on board with 36 percent choosing to down the hatch, compared to 35 percent of Americans and 33 percent of Brits.

    The Airline Passenger Experience Association(APEX) spoke to around 1,500 people, aged 18 and older, who have traveled by plane at least once during the last three months and were living in the United States, United Kingdom, Germany, Japan, China, Singapore, Australia and Brazil.

The results found Chinese travelers are most likely to nod off once the seat-belt sign switches off. They are also the first to take out their credit card for some in-flight shopping and the biggest fans of gaming. Americans on the other hand like to use their time in the air more productively—- when not drinking—- choosing to work while flying at 35,000 feet.

Meanwhile, Brits and Germans are the best at making chat with random strangers—-spending 50 percent more time than any other nationality. Comparatively, Brazilians conduct their conversations online via email, messaging apps or social media.

    Despite plane food having a bad reputation, seven out of ten interviewees said they were happy to eat up on the selection of in-flight snacks and meals. In-flight magazines were also popular with four out of five passengers.

    The international flyers did however express their desire for better in-flight entertainment. “The industry has greatly improved the comfort, entertainment and onboard service, and passengers are accepting those improvements” said Russell Lemieux, APEX executive director. “At the same time, passengers are demanding more from their air travel experiences which will drive more improvements touching all aspects of the journey.” he added.

    China will follow up on its successful mission (任务) to the far side of the moon by sending a probe to Mars next year, one of its top space scientists said Sunday. Wu Weiren, chief designer of China's lunar exploration program, said the red planet was the natural next step. "Next year we'll launch a Mars probe to orbit around the Mars, land on it and probe it," he said. China will also send another probe to take back samples from the moon's surface.

    Wu's comments came as a Mars simulation(模拟) base opened in Qinghai's Qaidam Basin. According to the state-run Global Times, while the red rocky area bears a strikingly similarity to Mars, it's extremely difficult to simulate Mars due to its special natural features and hostile environment—low air pressure, strong radiation and frequent sandstorms, as well as vast differences in geography.

    China didn't send its first satellite into orbit until 1970, by which time America had already landed an astronaut on the moon, but it's been catching up fast. Since 2003, China has sent six crews into space and two space labs into Earth's orbit. In 2013, China successfully landed a rover, Yutu 1, on the moon, becoming only the third country to do so.

    Last December, China landed another probe and a rover, Yutu 2, on the far side of the moon. Progress has been slow going since then: due to the extreme conditions there, the rover often has to hibernate to preserve its capabilities for further exploration, Wu said. "The temperature there is minus 190 degrees Celsius, which all components and parts cannot stand. So we let it sleep for a while, making sure it can spend the night safely. A few days ago, it woke up automatically to work. We've gained lots of data in the past few days, and we're going to make the data known to the world,” Wu said.

    We lived in a quiet neighborhood. One evening I heard a loud crash. Earlier my wife had asked me to the store for soft drinks. My teenage daughter Holly practiced her driving, so I sent her to the store in my truck.

    At dinner my son talked about how much he liked my truck. I enjoyed having it, but I said: "My heart is not set on that truck. I like it but it is just metal and won't last forever. Never set your heart on anything that won't last. "

    After hearing the loud noise, the whole family ran outside. My son shouted: "Holly crashed your truck."

    The accident took place in my own driveway. Holly had crashed my truck into our other vehicle(交通工具), the family van. In her inexperience, she had confused the brake(刹车) and the gas pedal(油门). Holly was unhurt physically, but she was crying, "Dad, I'm sorry. I know how much you love this truck." I held her in my arms as she cried.

    I still remembered how sad Holly was the night she crashed our truck, and how I comforted her. When Holly thinks back on her life, I want her to know that I love her a thousand times more than any piece of property(财产).

    I repaired the van, but the dent(凹痕) in my truck is still there today. Every day it reminds me of what really matters in my life.