With around 100 students scheduled to be in that 9:00 am Monday morning lecture, it is no surprise that almost 20 people actually make it to the class and only 10 of them are still awake after the first 15 minutes; it is not even a surprise that most of them are still in their pajama's(睡衣). Obviously, students are terrible at adjusting their sleep cycles to their daily schedule.

    All human beings possess a body clock. Along with other alerting systems, this governs the sleep/wake cycle and is therefore one of the main processes which govern sleep behaviour. Typically, the preferred sleep/wake cycle is delayed in adolescents, which leads to many students not feeling sleepy until much later in the evenings. This typical sleep pattern is usually referred to as the “night owl” schedule of sleep.

This is opposed to the “early bird” schedule, and is a kind of disorder where the individual tends to stay up much past midnight. Such a person has great difficulty in waking up in the mornings. Research suggests that night owls feel most alert and function best in the evenings and at night. Research findings have shown that about 20 percent of people can be classified as “night owls” and only 10 percent can be classified as “early birds” —— the other 70 percent are in the middle. Although this is clearly not true for all students, for the ones who are true night owls, this gives them an excellent excuse for missing their lectures which unfortunately fall before midday.

    Thomas Edison received a patent(专利) for his kinetoscope(电影放映机) on August31, 1887. It was a machine for viewing moving pictures. Edison had hoped to combine his no invention with the phonograph(留声机), which he had invented 10 years earlier. He thought that people would like to watch moving pictures that went along with the sound. He was not able to make them work together. The kinetoscope, however, was a popular attraction by itself. A person looked through small holes in a box-like machine and saw pictures in action. One of the first films made showed a man sneezing.

    A problem with this invention was that only one person could view the moving pictures at a time. By 1891, Edison had invented a projector that showed the film on a screen. Many people could watch together.

    In 1893, Edison built a motion-picture studio. He made over 300 silent films. Most of them were short. That was because the pictures flashed, or shook a lot. It was hard for people to watch more than 10 minutes at a time.

    The first films were mostly of real events. They would show famous people walking somewhere, cars on a street, burning houses, and other news stories. Then comedies and short dramas were made.

    Edison's movie studio closed in 1918. By then other companies were also making films. Better cameras were made. Sound was added. Then color came along. Today, movies are among the most popular forms of entertainment.

    Among the most popular forms of dieting is the South Beach diet, developed by Arthur Agatston of Miami, Florida. Dr. Agatston developed the South Beach diet for his patients with heart problems to lose weight. Since weight matters a lot in keeping heart healthy and traditional low-fat diets were too difficult for them to stick to, Dr. Agatston decided to create a plan that could help his patients. At first, the diet was just for his patients. Soon, thanks to his patients' success, the diet became the buzz in Miami, and eventually, word spread across the nation.

    This diet focuses on a healthy balance between carbohydrates（碳水化合物）and fats. It is based on eating a combination of “good” carbohydrates and fats, while limiting those “bad” ones. It is divided into three different phases.

    The first phase lasts for two weeks and is the strictest of the three. During this phase, you are asked to restrict（限制）all carbohydrates (good and bad). You are allowed to eat all types of fish, cheeses, eggs, and nuts, and a large number of vegetables. Most dieters can expect to lose between 8 and 12 pounds during this phase.

    During Phase 2, you are allowed to reintroduce some of those carbohydrates that are not allowed before. You are encouraged to start eating carbohydrates that have a low glycemic index（升糖指数）. But you should keep in mind that the key is moderation（适度）. Most people continue to lose 1-2 pounds per week. You continue with this phase until you reach your target weight.

    Phase 3 is designed to help you keep your weight. During Phase 3, you can reintroduce some of the carbohydrates that have a higher glycemic index, although again, this should be in moderation. Phase 3 is meant to be a way of life.

    Astronauts in the space stations for long missions often work very long days. Tasks are scheduled(安排) so tightly that break times are often used to finish the day's work. It's especially hard for long missions on the International Space Station (ISS). ISS crew members usually live in space for at least a quarter of a year. They work five days on and two days off to mimic the normal way they do things on Earth as much as possible. Weekends give the crew valuable time to rest and do a few hours of housework. They can communicate with family and friends by email, Internet phone and through private video meetings.

    While astronauts cannot go to a baseball game or a movie in space, there are many familiar activities that they can still enjoy. Before a mission, the family and friends of each ISS crew member put together a collection of family photos, messages, videos and reading materials for the astronauts to look at when they will be floating 370 kilometers above the Earth. During their mission, the crew also receives care packages with CDs, books, magazines, photos and letters. Today, the Internet can be used on the ISS, giving astronauts the chance to do some “web surfing” in their personal time. Besides relaxing with these more common entertainments, astronauts can simply enjoy the experience of living in space.

    Many astronauts say that one of the most relaxing things to do in space is to look out of the window and stare at the universe and the Earth's vast land mass and oceans.

All students have bad times. What do they usually do when they get into trouble?

My mom is like my friend. I talk about everything to her. Whenever I have some trouble, I can get good advice from her. I have another good friend — my diary. It knows all my secrets. Talking with my two friends always makes me feel better. 

 —— Linda

Laughing helps me when I'm upset. I usually watch funny movies and TV shows. I also love spending my hard time with my best friend Dave. He is humorous and always makes me laugh. 

 —— Peter

Every time I feel bad, I go climbing alone. The study says exercising can help cheer one up (精神振奋). And the beautiful view at the top of the mountain makes me forget all my troubles. Sometimes I shout at the mountain top. It feels fantastic. 

 —— John

The American Psychological Association（APA） has issued its first advisory on social media use in adolescence（青春期）. What's most striking in its data based on recommendations is how little we really know about how these apps affect our kids.

The relative newness of platforms like Snapchat and Tik Tok means little research is available about their long-term effects on teen and tween brains. Getting better data will require significant funding—and much more openness from tech companies.

"What little evidence we do have unsurprisingly suggests that social media trades on motivators that aren't great for young brains. Many kids' first exposure to social media occurs at the worst possible time when it comes to brain development," says Mitch Prinstein, a psychologist and neuroscientist at the University of North Carolina（UNC）.

"Things like 'button and artificial intelligence（in general）' are going to affect young people's brains in a way that's very different from adult brains when it comes to the desire to stay online and to say or do almost anything to get followers." When it comes to social interactions, he compares kids' brains to a car with a huge gas pedal and weak brakes（刹车）.

Earlier this year, Prinstein and his UNC colleagues published the results of one of the first studies of how the adolescent brain reacts to social media. The team surveyed a group of middle schoolers to understand their social media habits, and then stuck them in an MRI machine to watch their brains as they reacted to social rewards or punishments. They found that 12-year-olds who habitually checked social media had distinct neural patterns, with more activities over time in parts of the brain associated with motivation, salience（or where attention is focused） and cognitive control.

The team didn't weigh in on whether those differences were good or bad, or whether the relationship was causal or correlational. But their work points to the need for more research. It should also remind parents of the need to be keenly aware of social media's hidden influence on still-developing brains.