Have your parents ever inspected your room to see if you cleaned it properly? Imagine having your entire houses, garage, and yard inspected at any time -- with no warning. Inspections were a regular part of lighthouse (灯塔) living, and a keeper's reputation depended on results. A few times each year, an inspector arrived to look over the entire light station. The inspections were supposed to be a surprise, but keeper sometimes had advance notice.

    Once lighthouses had telephones, keepers would call each other to warn that the inspector was approaching. After boats began flying special flags noting the inspector aboard, the keeper's family made it a game to see who could notice the boat first. As soon as someone spotted the boat, everyone would do last-minute tidying and change into fancy clothes. The keeper then scurried to put on his dress uniform and cap. Children of keepers remember inspectors wearing white gloves to run their fingers over door frames and windowsills looking for dust.

    Despite the serious nature of inspections, they resulted in some funny moments. Betty Byrnes remembered when her mother did not have time to wash all the dishes before an inspection. At the time, people did not have dishwashers in their homes. In an effort to clean up quickly, Mrs. Byrnes tossed all the dishes into a big bread pan, covered them with a cloth and stuck them in the oven. If the inspector opened the oven door, it would look like bread was baking. he never did.

    One day, Glenn Furst's mother put oil on the kitchen floor just before the inspector entered their house. Like floor wax, the oil made the floors shiny and helped protect the wood. This time, though, she used a little too much oil. When the inspector extended his hand to greet Glenn's mother, he slipped on the freshly oiled surface. "He came across that floor waving his arms like a young bird attempting its first flight," Glenn late wrote. After he steadied himself, he shook Glenn's mother's hand, and the inspection continued as though nothing had happened.

    Mark Twain, the famous American writer and a great master of humor, liked to play jokes on others. But once a joke was played on him. One day Mark Twain was invited to give a talk in a small town. At lunch he met a young man,one of his friends.

    The young man said that he had an uncle with him. He told Mark Twain that his uncle never laughed or smiled, and that nobody and nothing was able to make his uncle smile or laugh.

    “You bring your uncle to my talk this evening,” said Mark Twain. “I'm sure I can make him laugh.”

    That evening the young man and his uncle sat in the front. Mark Twain began to speak. He told several funny stories and made everyone in the room laugh. But the man never even smiled. Mark Twain told more funny stories, but the old man still kept quiet. Mark Twain continued to tell his funny stories. Finally he stopped. He was tired and quite disappointed.

    Some days later, Mark Twain told another friend what had happened. “Oh,” said his friend,“I know that man. He's been deaf for years.”

    Researchers found that walking around with a forced smile and fake happiness simply leads to people feeling unhappier. So, putting a brave face on your sadness could be harmful. The research also found that women suffered more than men when pretending to be happy.

    Dr. Brent Scott, who led the study, said employers should take note because forcing workers to smile when dealing with the public can result in bad outcomes. He said, “Smiling for the sake of smiling can lead to emotional tiredness, and that's bad for the organization.” He also said the research showed customer-service workers who had “fake smiles” throughout the day didn't want to work, so their productivity dropped.

    The study is one of the first of its kind to examine emotional expressions over a period of time and compare the different effects on men and women. Dr. Scott's team examined the effects of “surface acting”, or fake smiling, compared to “deep acting”, or making people smile by thinking of pleasant memories.

    Dr. Scott said, “Women were harmed more by surface acting, meaning their moods worsened even more than men's. However, they were helped more by deep acting, which means their moods improved more by thinking of pleasant memories.”

    According to Dr. Scott women tend to suffer more when pretending to be happy because they are expected to be more emotionally expressive than men. Therefore, forcing a smile while feeling down is more likely to go against their normal behavior and cause more harmful feelings.

    Although deep acting can improve moods a little in the short term, Dr. Scott says it's not a long-term solution to feeling unhappy. There have been some suggestions that if you do this over a long period you start to feel unreal. You're trying to develop positive emotions, but at the end of the day you may not feel like yourself any more.

    Courses & Curriculum of the College of Arts & Sciences in Cornell

    While elephants born without tusks (长牙)are not unheard of，they normally form just 2 to 6 percent of the population. However, that is not the case at Mozambique's Gorongosa National Park, where an astonishing 33 percent of female elephants born after the country's civil war ended in 1992 are tuskless. While that may appear to be just a coincidence, Joyce Poole, an elephant behavior expert, has another theory. The researcher thinks we may be witnessing unnatural evolution of the species due to the constant hunting of elephants for valuable ivory.

    Poole says before the country's 15-year-long civil war, the 100,000-acre park was home to over 4,000 elephants. However, by the time the conflict ended in 1992, about 90 percent of them had been killed for ivory to help finance weapons (武器)and meat to feed the soldiers. Of the less than 200 survivors, over 50 percent of adult females had no tusks. Therefore, it is not surprising that the park's tuskless elephant population has grown greatly.

    This is not the first time researchers have observed a great change in the population of elephants. At Zambia's South Luangwa National Park and Lupande Game Management Area， areas which were heavily hunted in the 1970s and 1980s, 35% of elephants 25 years or older and 13% of those younger than 25 are now without tusks. A 2008 study published found that the number of tuskless females at the Ruaha National Park in Tanzania went from 10.5 percent in 1969 to almost 40 percent in 1989, largely due to illegal hunting for ivory.

    The recent ban on ivory in both the US and China should help get rid of, or at least reduce, elephant hunting. However, scientists are not sure how long it will take for elephants with a higher rate of tuskless females, to change the trend.

    The idea that you can use humor, laughter, and play to make you healthier probably seems too simple to be true. However, it is really true and simple. The sense of humor, laughter and play plays an important part in keeping you healthy.

    Treat the blues with a sense of humor, which is closely tied to laughter. Laughter is infectious. Have you ever heard a big laugh of a young child and been able to keep yourself from smiling? When laughter is shared between people, it makes them closer to each other and increases their happiness. Smiling is the beginning of laughter and a smile is also just as infectious as laughter is. You can experience something by smiling at everyone around you, and you will feel happier just by sharing a smile, even with a stranger.

    Play is an important part of making sure that we stay healthy. We are often encouraged to make sure our children play, and are told of the benefits of being out playing. However, what we often forget is that it is just as important for old people to make play be part of their life as it's for children. Physical play is important for the old and it certainly helps prevent illness. While the studies are still in the early stages, the studies that have been done have shown that physical play certainly plays a part in preventing cognitive (认知的) falling.