What is it that makes people laugh? More than two thousand years ago the ancient Greek philosopher Aristotle defined (定义) jokes as the pleasure that results from a feeling of triumph(胜利) by showing we're better than someone else in a certain way. According to Aristotle and many other philosophers，all jokes depend mainly on showing inferiority in another person or group of persons—that is，putting it clearly，on showing that they are worse off than ourselves. Jokes raise our good opinion of ourselves at someone else's expense.

Showing how much better than other people we are is only one reason we like jokes. Someone may also use a joke to express their anger or their cruelty or any other kind of action that is not acceptable to us. We feel free to laugh when we hear about someone sliding on a banana skin. The joke lets us express those attitudes which are usually unacceptable to society. This is probably the reason why some of the jokes，especially those involving cruelty，are so popular with certain people.

    Besides，all jokes depend on our enjoyment of laughing at something that is strange and out of place because it's different from things which are happening around it. The same situation can be either sad or pleasant，depending entirely on how strange and out of place it is. If a girl in a bathing suit falls into a swimming pool，we don't laugh because nothing unusual has happened. But if a man in a smart suit falls in，the situation is at once unusual in a pleasant way and we laugh. A good joke-teller will always try to build up a situation in which one thing is expected until something unexpected suddenly happens，and so we laugh.

Student Job Center

    The human brain remembers negative experiences more easily than positive ones. Our brains have developed this way because threats, like dangerous animals, had a more immediate effect on our ancestors' survival compared to positive things like food or shelter. As a result, you likely know what makes you unhappy, but do you know what makes you happy?

    Research suggests that our level of happiness depends partly on factors we cannot control—our genes and our life circumstances. But our level of happiness is also shaped by the choices we make. If you've been chasing wealth, fame, good looks, material things and power, you may be looking for happiness in all the wrong places. Psychologists suggest that the following habits make people happier.

    People who form close relationships tend to be happier than those who do not. The number of friends we have is not important. What matters is the quality of our relationships. Relationships that bring happiness usually involve the sharing of feelings, mutual respect, acceptance, trust and fun.

    People who exercise regularly improve both their physical and mental well being. Some research has shown that exercise can be as effective as medication in treating depression.

    When we are so interested in an activity we enjoy that we lose track of time, we are in a state of flow. The activity could be making art, playing piano, surfing, or playing a game. People who experience flow in their work or hobbies tend to be happier.

    People are more likely to be happy if they know what their strengths are and use them regularly, People who set goals and use their strengths to achieve them tend to be happier. People are especially happy when they can use their strengths to serve the greater good.

    People who think positively by being grateful, mindful and optimistic are more likely to be happy. Being grateful means being thankful, Bejing mindful means being open to, focusing on and enjoying the experiences of the present moment. Being optimistic means being hopeful about the future.

    Over millions of years, African penguins have developed a keen sense of where to find food. Once they're old enough, they set off from the shores on which they were hatched（孵化） for the first time and swim long distances in search of tasty fish like anchovies and sardines. But they don't search directly for the fish themselves. When African penguins head out to sea, they look for areas with low surface temperatures and high chlorophyll（叶绿素）. Because those conditions signal the presence of algae（藻类）. And lots of algae means lots of plankton（浮游动物）, which in turn means lots of their favorite fish. Well, that's what it used to mean.

    Climate change plus overfishing have made the penguin feeding grounds a mirage（海市蜃楼）. The habitat is indeed plankton﹣rich, but now it's fish﹣poor. Researchers call this an "ecological trap." "It's a situation where you have a signal that previously pointed an animal towards good﹣quality habitat. That habitat has been changed, usually by human pressures. The signal stays, but the quality in the environment gets worse."

    Richard Sherley, a zoologist at the University of Exeter and his team used satellite imaging to track the African penguins from eight sites along southern Africa. Historically, the birds benefited from tons of fish off the coasts of Angola, Namibia and western South Africa, but now they're going hungry.

    "I was really hoping we'd see them going east, and finding areas which the fish had moved to but it ends up being quite a sad story for the penguins." said Richard.

    The researchers calculate that by falling into this ecological trap, African penguin populations on South Africa's Western Cape have declined by around 80 percent.

    Some research groups are exploring the idea of moving them to a place where they can't get trapped, like the Eastern Cape. But Sherley thinks that a solution in the long run means making and carrying out rules to create more sustainable（可持续的） fishing industry, which needs public support.

Guide to Stockholm University Library

    Our library offers different types of studying places and provides a good studying environment.

Zones

    The library is divided into different zones. The upper floor is a quiet zone with over a thousand places for silent reading, and places where you can sit and work with your own computer. The reading places consist mostly of tables and chairs. The ground floor is the zone where you can talk. Here you can find sofas and armchairs for group work.

Computers

    You can use your own computer to connect to the wi-fi specially prepared for notebook computers; you can also use library computers, which contain the most commonly used applications, such as Microsoft Office. They are situated in the area known as the Experimental Field on the ground floor.

Group-study places

    If you want to discuss freely without disturbing others, you can book a study room or sit at a table on the ground floor. Some study rooms are for 2～3 people and others can hold up to 6～8 people. All rooms are marked on the library maps.

    There are 40 group-study rooms that must be booked via the website. To book, you need an active University account and a valid University card. You can use a room three hours per day, nine hours at most per week.

    Storage of Study Material

    The library has lockers for students to store course literature. When you have obtained at least 40 credits, you may rent a locker and pay 400 SEK for a year's rental period.

    Rules to be Followed

    Mobile phone conversations are not permitted anywhere in the library. Keep your phone on silent as if you were in a lecture and exit the library if you need to receive calls.

    Please note that food and fruit are forbidden in the library, but you are allowed to have drinks and sweets with you.

    Dearborn Heights, Michigan—2.7 million children under 18 have a parent in prison, and women put in local prisons are the fastest growing population. Shawna Reynolds has seen some of those women up close while working in the corrections system(劳教所) for 17 years, and she was encouraged to try something different.

    After seven years of education and collecting as much money as she could, Shawna created About Face Course Correction—a one-year rehabilitation program(康复项目) that offers a more personal way to help non-violent women prisoners. The program includes classes for women to finish their education, find a job and So on. "You can't expect people who have been in prison to stay in prison," Shawna says. "YOU want them to be helpful people but if you are not going to help them, it's not going to happen."

    The women live free for a year in a house in Dearborn Heights, Michigan. Women like 20-year-old Jennifer Douglas, who dropped out of school, took drugs(吸毒), and has spent years in and out of prison. She says, "I was doing things I would never have thought I would do in my whole life. Because of About Face, Jennifer's life is changing. " "Everyone is starting to trust me again and proud of me and what I'm doing," she says. "It's helped me a lot. It has kept me on the right track."

    There are many other women like Jennifer. Every woman's story is different, but each woman is important. And Shawna is determined to break the cycle and help them turn their lives around. She is using her own money and donations to pay for the house and this program. If you would like to donate, please visit their Go Fund Me account here.