“A photograph that one has taken of oneself, typically with asmart phone or webcam and uploaded to a social media website” is the definitionof “selfie” in the Oxford English Dictionary. In fact, it wasn't even in thedictionary until August of last year. It earned its place there because peopleare now so obsessed with (对……痴迷) selfies ─ wetake them when we try on a new hat, play with our pets or when we meet a friendwhom we haven't seen in a while.

But is there any scientific explanation for this obsession?Well, you should probably ask James Kilner, a neuroscientist(神经系统科学家) atUniversity College London.

Through our lifetime we become experts at recognizing andinterpreting other people's faces and facial expressions. In contrast,according to Kilner, we have a very poor understanding of our own faces sincewe have little experience of looking at them ─ we just feel them most of thetime.

This has been proved in previous studies, according to the BBC.

Kilner found that most people chose the more attractive picture.This suggests that we tend to think of ourselves as better-looking than weactually are. To further test how we actually perceive our own faces,Kilner carried out another study. He showed people different versions of theirown portrait ─ the original, one that had been edited to look less attractiveand one that was made more attractive ─ and asked them to pick the versionwhich they thought looked most like them. They chose the more attractiveversion.

But what does it say about selfies? Well, isn't that obvious?Selfies give us the power to create a photograph ─ by taking it from variousangles, with different poses, using filters (滤色镜) and so on ─that better matches our expectations with our actual faces.

“You suddenly have control in a way that you don't have innon-virtual(非虚拟的)interactions," Kilner told the Canada-based CTV News. Selfies allow you“to keep taking pictures until you manage to take one you're happy with”, heexplained.

    It was my first day back home since starting college. A lot had changed in the last year. Not with my hometown but with me. I had left as a 17-year-old boy and had now returned as an 18-year-old man. In the city, I was living on my own, had a part-time job and was studying. Even the government recognized I was an adult: I had a driver's license. So here I was, on my summer vacation, walking down the main street with my father, desperate for him to acknowledge how mature I was. When his recognition failed to appear, I took matters into my own hands. “Dad,” I said casually, “I'm thirsty. Let's go for a beer.” It was the first time I'd ever mentioned beer in front of my father, let alone ask him to drink one with me.

    He turned to me with a curious expression on his face. “A beer? Well, 1 guess you're old enough now. Let's go to Sailors' Bar. It's where my cousin Tom, your uncle, used to drink. You remember him, right?”

    I had only some vague recollection of my uncle. He was the black sheep of the family. We didn't talk about him much. What ever happened to Uncle Tom, Dad? I haven't seen him in years,” I said as we continued towards the bar.

     “Neither have I, unfortunately. He was a good kid once. But things changed,” my father said mournfully. As a boy, he explained, there had been no better-behaved boy than Tom. But after leaving school, he moved to the city and fell in with bad company. He started going out every night, drinking in nightclubs and playing cards. Soon he lost everything and had to beg his mum to pay his debts. She agreed on condition that he returned home.

    My dad took a deep breath and continued his tale. "Things settled down for a while. He married a lovely woman, gave up his bad habits. But it didn't last. He was soon back to his old ways. He couldn't resist. He was at Sailors, Bar almost every night. His poor mother died of grief and shame. His wife followed her soon after.

     “What ruined him was alcohol He told me once, when a man begins drinking, he never knows where it'll end. ‘So', Tom warned me. ‘be cautious about your first drink!'

     “He went from bad to worse. Last year Tom sent me a letter saying he had been found guilty of stealing, and sent to prison for ten years.”

    Dad finished talking just as we reached the front door of Sailors' Bar. “Anyway, here we are. Let's go in,” he said. But understood. I put my arm around my father and said, “I'm not thirsty anymore, Dad. Let's go home.”

    My friend Jason and I wanted to do something to help other people who are less lucky and help us grow at the same time. After we decided that we would volunteer in Nepal, I did some surveys on the Internet and I found an organization called Volunteer(志愿者) Nepal and felt strongly that it was the right choice for us.

    While making our plans, Jason and I realized that others might like the chance to be a part of our experience. So before leaving for Nepal, we asked the people we know whether they would be interested in donating(捐赠) money or goods to Nepal Orphans Home.

    One friend, whose family owns a shop called Drake Supermarket, told others about it. Many people wanted to donate something. We received donations that filled 29 boxes with sporting goods, toys, coloring books, pencils, children's books, and more, The boxes were later taken to Drake's warehouse(仓库) where I prepared them for shipment. Drake agreed to ship them to Nepal for free .

    The boxes had arrived at the Volunteer House when we arrived there. The next day, Jason and I opened the boxes. The children from the orphanages(孤儿院) stood in a line and were able to choose a gift. This took about an hour, but the looks on their faces and the happiness that we saw in their eyes made it one of the best days of our life.

    We visited the orphanages there in the following days. Being with the children at the orphanages was both sad and wonderful. I'm sure that anyone who has volunteered will understand what I mean by that. My experience as a volunteer was very useful. It has changed me as a person and the way I viewed life in the past.

    “An apple a day keeps the doctor away.” Similarly, if we drink a little more water every day, we may find that we need to go to the doctor a lot less often. A healthy diet is made up of water and a great many different kinds of foods. We know that healthy foods like fruits, vegetables and fish, are important as they provide us with energy and fiber, without giving us too much fat and sugar. But why is water important?

    The human body needs water to survive. Water is important as it carries poisons and waste out of our bodies. So, doctors advise us to drink plenty of water, much more than the small amount we need to stay alive.

    Some doctors believe that water is important for our health in all kinds of ways. They believe that a great many illnesses and health problems start as a result of dehydration(脱水)—a lack of water in the body. Most people are dehydrated at least some of time, although they probably don't know it. It is surprising to learn that if we feel thirsty, we are already in the first stage of dehydration. In fact, we are advised to drink water before we feel thirsty.

    These doctors think that health problems such as headaches, high blood pressure and asthma(哮喘) could be helped if people drink more water. They also believe that drinking more water can help people who are overweight. Water contains no calories so it will not make us put on weight. If we drink water, we will probably drink less sugary soft drinks such as Coca-cola. Doctors also believe that drinking more water may stop people from overeating. They say that many people think that they are hungry when they are, in fact, thirsty. Doctors suggest, therefore, that we eat less food and drink more water. There are still many health problems that cannot be solved by drinking water, so we should not stop going to seeing the doctor completely. However, if we make a decision to drink water every day, we may find that we need to go to the doctor a lot less often.

    Festivals are a great way to experience a destination in a different way. This article will fuel your wanderlust（漫游癖）and guide you to the best festivals.

    St Patrick's Day

    Where: Dublin, Ireland & New York, USA

    When: 17 March

    St Patrick's Day has taken place in New York city on March 17th since 1762. On this day, the whole city turns green. Many Irish make traditional bread on this day. It is one of the most fun days the of the year in New York City every year, when the whole city turns into a big green party.

    SXSW

    Where: Austin, USA

    When: 10-19 March

    Like free things? Yeah me too! Free food, drink and music sound good? Welcome to Austin, Texas. SXSW is a festival for those who work in the music and film industries. There are "free" shows. You di have to pay but not by handing over cash; you have to give some time to queue but it is worth it to see some popular stars.

    King's Day

    Where: Amsterdam, Netherlands

    When: 27 April

    Every year on April 27 Amsterdam turns a very bright color of orange for King's Day, which is the birthday of King Willem-Alexander. It is a crazy fun celebration when the center of the city is car, bus, and bike-free. It is a market day, when anyone can sell pretty much anything. Tips: Take a jacket with you, wear orange, and bring cash.

    Just for Laughs

    Where: Montreal, Canada

    When: 14-30 July

    For comedy lovers there is no other festival in the world better than Montreal's Just for Laughs. The festival concentrates most of its shows in the Latin Quarter. During the day street performers delight the crowds and at night the city comes alive with comedy all over the city.

    Some educators told us that more years of school could help students get higher scores on intelligence tests. That was a finding of a study of teenage males in some countries. Now, another research shows that physical activity may help students do better in their classes.

    The research comes as educators in some countries are reducing time for activities like physical education. They are using the time instead for academic(学术的) subjects like math and reading. The studies appeared between 2008 and 2014. They included more than 55,000 children, aged 6 to 18.

    Amika Singh: "According to the results of our study, we can conclude that being physically active is beneficial for academic performance. There are, first, Physiological explanations, like more blood flow, and so more oxygen to the brain. Being physically active means there are more hormones(荷尔蒙) produced like endorphins(内啡肽). And endorphins make your stress level lower and your mood improved, which means you also perform better."

    Also, students taking part in organized sports learn rules and how to follow them. This could improve their classroom behavior and help them keep their mind on their work.

    The study leaves some questions unanswered, however Ms Stash says it is not possible to say whether the amount or kind of activity affected the level of academic improvement. This is because of differences among the studies.

    The researchers said they found only two high­quality studies. They needed more high­quality studies to confirm(证实) their findings. They also pointed out that "results for other parts of the world may be quite different".

    Still, the general finding was that physically active kids are more likely to do better in school. Ms Singh says schools should consider that finding before they cut physical education programs. Her paper on "Physical Activity and Performance at School" is published in the Archives of Pediatric and Adolescent Medicine.