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.

    A ground-based system that uses much stronger signals than GPS can find your location in cities and indoors. It is a new positioning system that could compete with GPS to make sure you never lose your directions again.

    Instead of satellites, Locata uses ground-based equipment to send a radio signal over a localized area that is a million times stronger on arrival than GPS. It can work indoors as well as outdoors, and the makers claim that the receivers can be shrunk(缩小) to fit inside a regular cell phone. Even the US armies, which invented GPS technology, signed a file last month agreeing to a test of Locata at the White Sands Missile Range in New Mexico.

    “This is one of the most important technology developments for the future of the positioning industry,” says Nunzio Gambale, CEO and co-founder of the firm Locata, based in Griffith, Australia.

    As for the Locata's correctness, Christopher Morin of the US Air Force tested it recently at White Sands, and it worked to within 18cm along any axis(轴). Morin said it should be possible to get the exactitude down to 5cm.

    The tests were performed in an open desert where GPS also worked beautifully, but its signal was weak—like a car headlight from 20,000 kilometers away—and easily cut off by solid objects(实心的物体). Locata's signal was far stronger, though not guaranteed to work in a complex urban environment, said David, speaker of the UK' s General Lighthouse Authorities.

    Locata's technology will face competition in the race to transform indoor navigation. But it could shine in specific areas, Gambale said. Robots with Locata could easily navigate inside buildings without the complex optical(视觉的) systems they need at the moment. And the process that handles correct location data could not only guide you around a mall, railway station or airport, but also take you to the exact shelf in a shop for the product you want. It would be small and cheap enough for smart phones and it should be available within five years—a similar path to the one GPS took on its way towards the world, he said.

    Christopher Thomas, 27, was a writer by night and a teacher by day when he noticed he was always tired and was losing weight fast. Diagnosed with diabetes (糖尿病), Thomas would need to inject himself with insulin (胰岛素) three times a day for the rest of his life or risk nerve damage, blindness, and even death. And if that weren't bad enough, he had no health insurance.

    After a month of feeling upset, Thomas decided he'd better find a way to fight back. He left Canton, Michigan for New York, got a job waiting tables, nicknamed himself the Diabetic Rockstar, and created diabeticrockstar.com, a free online community for diabetics and their loved ones—a place where over 1,100 people share personal stories, information, and resources.

    Jason Swencki's son, Kody, was diagnosed with type diabetes at six. Father and son visit the online children's forums (论坛) together most evenings. “Kody gets so excited, writing to kids from all over,” says Swencki, one of the site's volunteers. “They know what he's going through, so he doesn't feel alone.”

    Kody is anything but alone: Diabetes is now the seventh leading cause of death in the United States, with 24 million diagnosed cases. And more people are being diagnosed at younger ages.

    These days, Thomas's main focus is his charity (慈善机构), Fight It, which provides medicines and supplies to people—225 to date—who can't afford a diabetic's huge expen­ses. Fight－it.org has raised about $23,000—in products and in cash. In May, Thomas will hold the first annual Diabetic Rockstar Festival in the Caribbean.

    Even with a staff of 22 volunteers, Thomas often devotes up to 50 hours a week to his cause, while still doing his full­time job waiting tables. “Of the diabetes charities out there, most are putting money into finding a cure，” says Bentley Gubar, one of Rockstar's original members. “But Christopher is the only person I know saying people need help now.”

    A new report shows that there are just 7,100 cheetahs now left in the wild. Cheetahs are in trouble now.

    According to the study, more than half of the world's surviving cheetahs live in one zone that covers six countries in southern Africa. Cheetahs in Asia have nearly died out. It's thought that only fewer than 50 cheetahs live in Iran.

    The cheetah runs across lands far outside protected areas. Some 77% of their habitat falls outside these protected areas. As a result, the cheetah struggles because these lands are increasingly being developed by farmers and the cheetah's food is decreasing because of human hunting.

    In Zimbabwe, the cheetah population has fallen from around 1,200 to just 170 in 16 years, with the main cause being major changes in land ownership.

    Researchers say that the threats cheetahs are facing have gone unnoticed for far too long. “Given the nature of the cheetah, it has been difficult to gather information on them,” said Dr Sarah Durant, the report's lead author. “Our findings show that the large space requirements for cheetahs and various threats faced by them in the wild mean that they are likely to be in danger of dying out.”

    Another big concern about cheetahs has been the illegal trafficking (非法交易) of young cheetahs. The young cats can fetch up to $10,000 on the black market. Some 1,200 young cheetahs are known to have been trafficked out of Africa over the past 10 years but around 85% of them died during the journey.

    If the cheetahs are to survive, then immediate efforts must be made.

    Night owls, people who stay up late and struggle to get out of bed in the morning, are more likely to die sooner than morning larks, the first study into their death rates has found.

    New research by the University of Surrey and Northwestern University in the US found that people who naturally stay up late were 10 per cent more likely to die within the six-and-a-half-year study period compared to those who preferred the morning.

    Researchers say that the ongoing stress of operating in a traditional 9-5 society was having a huge effect on millions of people and could be shortening their lives.

    “This is a public health issue that can no longer be ignored,” said Malcolm von Schantz, a professor of chronobiology at the University of Surrey. “We should discuss allowing evening types to start and finish work later, where practical. And we need more research about how we can help evening types deal with the higher effort of keeping their body clock in line with sun time”.

    The research involved nearly 500,000 Brits aged between 38 and 73 and found that around nine per cent considered themselves evening people, while 27 per cent identified as morning types.

    In the new study, Scientists found owls had higher rates of diabetes, psychological disorders and neurological disorders. But the team has previously shown that whether someone is an owl or a lark is half genetic and half environment, meaning there may be ways to keep body clock issues under control.

    The team recommends that night owls can help themselves by trying to become exposed to light early in the morning and not at night. Keeping regular bedtimes, maintaining a healthy lifestyle and trying to do tasks earlier in the day can help to reset body rhythms.

    The study was published in the journal Chronobiology International.

    Do you always agree to do things that you are unwilling to do? Are you the type of person who always says "yes"? I've come to learn that it is very important to learn to say NO! It's okay. People are still going to like you. They may even respect you more because they know you are honest.

    I'm not saying to say "no" to someone who really needs your help. I'm talking about refusing that meeting that you really do not want to attend or that birthday party that you don't want to be a guest at.

    Think for a moment how you feel when you say YES to something that you really don't want to do. If you're like I once was, you can't sleep at night and you think about it too much. It weighs on your mind. You try to find ways out. Whatever you're saying to yourself, if you really wanted to go, you wouldn't have all of these thoughts.

    So, why not just say NO from the beginning? Maybe you feel like if you don't show up at the meeting (by the way, it is not the one you must attend) your boss isn't going to like you or your co-workers won't respect you. Maybe you feel as if your mom, dad or sisters won't love you as much if you don't do everything for them that they ask every occasion.

    If these people are your true friends, family members, or a good boss, they will like or love you the same no matter what. People treat you the way you teach them to, and if you're someone who always says "yes", then that's what they're expecting.

    You need to do what is right for you. Of course we do have real obligations in life to fulfill, but we do not have to do everything others want us to do.