Ever feel like you've been hit on the head after a bad night's sleep? According to scientists, the thought isn't as unbelievable as it seems.

    A study found going without sleep for just one night causes changes in the brain similar to those that occur after a blow to the head. The researchers said the healthy young men examined in the study showed a sudden increase in the same chemicals which indicate brain damage. Professor Christian Benedict, of Uppsala University, Sweden, explained that the chemicals NSE and S-100B are biomarkers for brain damage, such as concussion(脑震荡). He said, "What we found was their levels in the blood rose in the group that went without sleep for a night. This was not to the extent that would happen after a head injury, for instance, but it was still significant. During sleep, the brain cleans poisonous substances off itself."

    Benedict also said previous studies which linked a lack of sleep with increased risk of Alzheimer's, Parkinson's and multiple sclerosis could applaud his study. The rise of the chemicals in the blood after sleep loss may suggest not getting enough sleep contributes to a loss of brain tissue, he explained. Benedict, whose study is published in the journal Sleep, added, "In conclusion, the findings of our experiment indicate a good night's sleep may be critical to maintaining brain health."

    A third of the UK population suffer from sleep-related problems, while the average person now sleeps for only seven hours a night, compared with almost nine a few decades ago. Many scientists believe irregular sleeping patterns lead to illnesses ranging from aches and pains to heart disease, while less than eight hours' sleep a night can lower the IQ the next day.

    Travis is the manager of G&G where he is responsible for forty employees (雇员)and profits (利润) of over $2 million per year. He's never late to work. He does not get upset on the job. When one of his employees started crying after a customer screamed at her, Travis took her away. "Your working uniform is your shelter," he told her. "Nothing anyone says will ever hurt you. You will always be as strong as you want to be."

    Travis picked up that lecture in one of his G&G training courses, an education program that began on his first day and continues throughout an employee's occupation. The training has, Travis says, changed his life. G&G has taught him how to live, how to focus, how to get to work on time, and how to master his emotions (情绪). Most importantly, it taught him willpower.

    At the center of that education is an extreme focus on an all-important habit; willpower. Dozens of cases show that willpower is the single most important habit for a person's success.

    And the best way to strengthen willpower is to make it into a habit. "Sometimes it looks like people with great self-control aren't working hard—but that's because they've made it automatic," Angela Duckworth, one of the University of Pennsylvania researchers said. "Their willpower occurs without them having to think about it."

    The company spent millions of dollars developing programs of study to train employees on self-control. Managers wrote workbooks that serve as guides to how to make willpower a habit in workers' lives. Those courses arc, in part, why G&G has grown from a sleepy company into a large one with more than seventeen thousand stores and profits of more than $10 billion a year.

    The vast majority of us spend our entire lives pulled down by gravity. Then there are astronauts.

This small population of space travelers has given researchers a rare look at what happens to the human body when it's able to spend large amounts of time outside the downward pull of the Earth. This week, a study on one of the largest groups of astronauts yet —34 participants—was published in The New England Journal of Medicine.

    In the new study, a team of international radiologists supported by NASA looked at MRIs of the brains of astronauts before and after their trips to space. The scientists found that upon returning to Earth, many of the astronauts' brains had become repositioned inside their skulls, floating higher than before. In addition, the space between certain brain areas appeared to have shrunk. The changes were more common in astronauts who took longer trips into space.

    The team characterized astronaut trips as short (an average of less than 14 days) or long (an average of about 165 days). Radiologists who didn't know each astronaut's duration（持续时间）in space compared MRIs from before and after their trips.

    Of the 34 total astronauts involved in the study, 18 took long trips to space—spending most of that time on the International Space Station —and of those, 17 returned to Earth with smaller areas between the frontal lobe（脑前额叶）and parietal lobe（顶叶）. The same area of the brain also shrank for three of the 16 astronauts who took shorter trips with the US Space Shuttle Program. The researchers also found that 12 of the ISS astronauts and six of the space-shuttle astronauts returned home with their brains sitting slightly higher in their skulls than before.

    It's not clear what, if anything, these brain changes mean for the health of space travelers. In general, it appears the human body tolerates space travel fairly well: the time astronauts have spent in zero-gravity environments so far doesn't seem to have had any strong or long-lasting effects.

                                                      Four Wild Animal Species Were Endangered

    Maybe you can still see them at the zoo. But that doesn't mean they're doing alright in the wild.

    Tigers

    All six tiger species are endangered, with Suatran tigers and South China tigers at a seriously endangered status. The main reasons for their population decline are illegal hunting and destroyed habitats, as humans clear forests to gather timber and build roadways. Only about 3890 tigers presently live in the wild.

    Ground squirrels

    That's right, even squirrels are endangered, specifically the San Joaquin ground squirrel. Native to California, USA, these guys have been disappearing since 1979 on account of the construction and human developments going through their habitat. Their total population is unknown, but it could be anywhere between 124000 and 4130000.

    Giraffes

    The International Union for the Conservation of Nature recently put giraffes at a vulnerable status, the level just before endangered. The giraffe population has declined 40 percent in the last 30 years, primarily due to loss of habitat and illegal hunting. Some giraffes are killed just for their tails, which are considered status symbols in Africa.

    Asian elephants

    The main threat to Asian elephants, one of the most intelligent animals, is their shrinking habitat. As the human population grows, people invade their land to build roads and railway tracks. Elephants in Myanmar are at an especially high risk for being captured and traded or used illegally in the tourist industry. Fewer than 50000 are left on the entire continent.

    Green is an important color in nature. It is the color of grass and the leaves on trees. It is also the color of most growing plants.

    Sometimes, the word "green" means young, fresh and growing. For example, a greenhorn is someone who has no experience. In the 15th century, a greenhorn was a young cow or an ox whose horns(角)had not yet developed. A century later, a greenhorn was a soldier who had no experience in war. By the 18th century, a greenhorn had the meaning it has today—a person who is new in a job.

    Someone who is good at growing plants is said to have a green thumb(大拇指). The expression comes from the early 20th century. A person with a green thumb can make plants grow quickly and well.

    Green is also the color used to describe the powerful feeling , jealousy(嫉妒). The green-eyed monster （怪物）is not a dangerous animal from outer space. It is an expression used about 400 years ago by the British writer William Shakespeare in his play "Othello". It describes the unpleasant feeling when someone has something he wants. For example, a young man may suffer from the green-eyed monster if you get a pay rise and he does not.

    In most places in the world, a green light means to move ahead. In everyday speech, a green light means agree to continue with a project.

    Living and dealing with kids can be a tough job these days, but living and dealing with parents can be even tougher.

    If I have learned anything in my 16 years, it is that communication is very important, both when you disagree and when you get along. With any relationship, you need to let other person know how you are feeling. If you are not able to communicate, you drift apart()疏远). When you are mad at your parents, or anyone else, not talking to them doesn't solve anything.

Communication begins with the concerns of another. It means that you can't just come home from school, go up to your room and ignore everyone. Even if you just say "Hi", and see how their day was for five minutes, it is better than nothing.

If you looked up the word "communication" in a dictionary, it would say "the exchange of ideas, the conveyance（表达）of information, correspondence （通信）, means of communication: a letter or a message". To maintain (保持) a good relationship, you must keep communication strong. Let people know how you feel, even if it's just by writing a note.

    When dealing with parents, you always have to make them feel good about how they are doing as a parent. If you are trying to make them see something as you see it, tell them that you'll listen to what they have to say, but ask them politely to listen to you. Yelling or walking away only makes the situation worse.

    This is an example: one night, Sophie went to a street party with her friends. She knew she had to be home by midnight after the fireworks, but she didn't feel she could just ask to go home. That would be rude. After all, they had been nice enough to take her along with them. Needless to say, she was late getting home. Her parents were mad at first, but when Sophie explained why she was late, they weren't as mad and let the incident go. Communication is the key factor here. If Sophie's parents had not been willing to listen, Sophie would have been in a lot of trouble.

    Communication isn't a one-way deal: it goes both ways. Just remember: if you get into a situation like Sophie's, telling the other person how you feel and listening is the key factor to communication.