Have you ever lost your direction? Then you might find satellite navigation(satnav) systems(卫星定位系统) helpful.

    A satnav system uses groups of satellites. They send information to a receiver(接收器), such as your smartphone. Then they can find where you are.

The earliest satnav system is the Global Positioning System(GPS) of the United States. The US has put 24 satellites into space to make sure GPS can locate(定位) a person correctly and globally. Likewise, Russia's GLONASS and European Union's Galileo can also work globally.

    But China is catching up, building its own BeiDou Navigation Satellite System. BeiDou is China's homegrown satnav system, reported Xinhua. It was set up in 2000, when China sent BeiDou's first navigation experiment satellite into space. With it, China became the third country to build a satnav system after the US and Russia.

    BeiDou can find you wherever you are. It helps you go faster by finding shortcuts(捷径) and using correct directions. When you are in trouble and call the police, they will know exactly where you are if you have a cellphone that uses BeiDou.

    Today, there are more than 20 BeiDou satellites above our heads. And the system is able to offer open services to the Asia-Pacific region(亚太地区).

    In November, China plans to send more BeiDou-3 satellites into space. BeiDou-3's position accuracy(准确度) is less than five meters, Ran Chengqi, a senior designer of the satellite navigation system, told China Daily.

    By 2020, BeiDou is planned to have 35 satellites and begin serving globally, reported Xinhua.

    Are you sick of going to bed late and waking up tired? Then grab your hiking boots and a tent. A new study suggests that camping in the great outdoors for a couple of days can reset your body clock and help you get more sleep.

    The body clock is an internal system that tells our bodies when it's time to go to sleep and when it's time to wake up. Scientists track this clock by measuring the amount of melatonin (褪黑激素) circulating in a person's blood at any given time.

    In a healthy sleeper, melatonin levels rise a few hours before bedtime, stay high through the night, and then settle back down when it's time to wake up.

    In our modern society, however, most of us stay up many hours past sunset and would probably sleep in many hours after sunrise if we could. And the trouble is, your melatonin levels may still be high when your alarm clock goes off in the morning, which leads to fatigue. It may also have other health consequences as well, such as diabetes (糖尿病), overweight and heart disease.

    Professor Kenneth Wright of the University of Colorado in the US wanted to see if our body clocks can be reset by a short stay in nature. His team recruited (招募) fourteen physically active volunteers in their 20s and 30s. Nine went on a weekend camping trip, while the other five stayed home. At the end of the weekend, the researchers reported that in just two days, the campers' body clocks had shifted so that their melatonin levels began to rise more than an hour earlier than they did before they left on the trip. By contrast, the body clocks of the group that stayed home shifted even later over the course of the weekend.

    “This tells us we can reset our clocks fast,” Wright said.

    Therefore, if you want to change your sleep patterns you could try to increase your exposure to natural light during the day and decrease the amount of artificial light you see at night. And if that doesn't work，there's always camping.

    The latest study by the University of Florida has found that eating from smaller, less beautiful, and even paper plates will help prevent overeating. Eating with a fork instead of a spoon can help you lose weight, the researchers say. Much to their surprise, they find that putting mirrors in the dining room will also help reduce weight.

    The researchers asked 185 college students to choose a chocolate cake or a fruit salad, and evaluated the taste. Those who ate in a room with a mirror scored the taste of junk food much lower than those in a room without a mirror. But the taste of fruit salad remained the same in any case.

    Lead scientist, Dr. Ata Jami, says that a glance in the mirror tells people more than just about their physical appearance. It enables them to view themselves objectively and helps them to judge themselves and their behavior in the same way that they judge other people.

    The mirrors were found to push people to compare and match their own behavior with accepted social standards. The researchers believe it proves that people don't want to look in the mirror when they feel they are following the social standards. When they look in the mirror with mouths full of junk food, feelings of discomfort and failure can be increased. Therefore, the presence of the mirror lowers the taste of unhealthy food.

    However, researchers say this is only the case if people select the food they are eating, because they are responsible for that choice. The researchers suggest that mirrors be placed in dining rooms and other eating spaces, so that people will start eating more healthily.

    Most animals on land are known to us, but many living things underwater are not. Now let's get to know some of them.

    Sea cucumber

    Sea cucumber are strange animals living at the bottom of the sea. They wear brown or white green coats. When summer comes, they stay deep to sleep because they are afraid of heat. And when it is autumn, they move to shallow (浅的) water and get their food.

    Pike

    The pike is a kind of freshwater fish. They are good swimmers and like swimming near boats, waiting to be fed. They have sharp teeth to catch fishes. When they are young, they live in groups. However, when they grow up, they prefer to live alone.

    Cuttlefish

    A cuttlefish can swim quite fast, so it is also called rocket (火箭) fish. It has eight arms and two feelers on its head, just around its mouth. It ejects ink (喷墨) when it is in danger. Its meat is delicious, and it is often the first choice for many people.

    Octopus

    An octopus has long arms, with which to catch food and protect itself. When it is sleeping, one or two of its arms are still on duty, keeping moving. Once it feels something dangerous, it can wake up at once to take action.

    Most heroes are not super. They don't appear in comic books, on television, or in movies. They just do what they believe needs to be done to make their world a better place. Bike Batman is one of them.

    Bike Batman is a 30-year-old married engineer who lives in Seattle, Washington. He's a cyclist who also buys and sells bikes as a hobby.

    About three years ago, he was looking for a bike for his wife. He found one on Craigslist, a website where people list things they want to sell. As he often does, he also looked at Bike Index, a popular website that allows users to register their bikes and post reports when they're taken. The bike, which he was considering purchasing, clearly matched one reported stolen on Bike Index. Then he called the person who claimed to be the bike's owner and arranged to meet him— supposedly to complete the sale. When the two men met, Bike Batman told the thief, "You've got two options. You can wait until a police officer gets here, or you can just get out of here." You can imagine what the thief did.

    After that first success, Bike Batman developed a safer routine. When he sees questionable bike ads on Craigslist, he cross-references(对照) the image with bikes reported on Bike Index. Once he has confirmed it with the owner, he arranges a meet-up with the thief and will call the Seattle police department so that officers can participate in the action. In more than half of the 22 cases in which he has got back and returned bikes, the thieves have been arrested. In one case, Bike Batman even helped a family recover a wide range of prized possessions that suspects had stolen during a home burglary.

    His nickname came from a discussion with a police officer who suggested he be called "Robin Hood". Since he wasn't exactly stealing from the rich and giving to the poor, "Batman" seemed a better fit. The idea of a superhero punishing criminals feels pretty silly to him, but the main reason he continues his work is to keep up Seattle's reputation as a friendly city.