Can people change their skin color without suffering like pop king Michael Jackson? Perhaps yes. Scientists have found the gene that determines skin color.

    The gene comes in two versions, one of which is found in 99 percent of Europeans. The other is found in 93 to 100 percent of Africans, researchers at Pennsylvania State University report in the latest issue of Science.

    Scientists have changed the color of a dark-striped zebra-fish（斑马鱼） to uniform gold by inserting a version of the pigment (色素) gene into a young fish. As with humans, zebra-fish skin color is determined by pigment cells, which contain melanin (黑色素). The number, size and darkness of melanin per pigment cell determine skin color.

    It appears that, like the golden zebra-fish, light-skinned Europeans also have a mutation (变异) in the gene for melanin production. This results in less pigmented skin.

    However, Keith Cheng, leader of the research team, points out that the mutation is different in human and zebra-fish genes.

    Humans acquired dark skin in Africa about 1.5 million years ago to protect bodies from ultra-violet rays of the sun (太阳光紫外线), which can cause skin cancer.

    But when modern humans leave Africa to live in northern latitudes, they need more sunlight on their skin to produce vitamin D. So the related gene changes, according to Cheng.

    Asians have the same version of the gene as Africans, so they probably acquired their light skin through the action of some other gene that affects skin color, said Cheng.

    The new discovery could lead to medical treatments for skin cancer. It also could lead to research into ways to change skin color without damaging it like chemical treatment did on Michael Jackson.

When someone is happy, can you smell it?

    You can usually tell when someone is happy based on seeing them smile, hearing them laugh or perhaps from receiving a big hug. But can you also smell their happiness? Surprising new research suggests that happiness does indeed have a scent, and that the experience of happiness can be transmitted through smell, reports Phys.org.

    For the study, 12 young men were shown videos meant to bring about a variety of emotions while researchers gathered sweat samples from them. All of the men were healthy and none of them were drug users or smokers, and all were asked to abstain from drinking or eating smelly foods during the study period. 

    Those sweat samples were then given to 36 equally healthy young women to smell, while researchers monitored their reactions. Only women were selected to smell the samples, apparently because previous research has shown that women have a better sense of smell than men and are also more sensitive to emotional signaling—though it's unclear why only men were chosen to produce the scents.

    Researchers found that the behavior of the women after smelling the scents—particularly their facial expressions—indicated a relationship between the emotional states of the men who produced the sweat and the women who sniffed them. 

    “Human sweat produced when a person is happy brings about a state similar to happiness in somebody who breathes this smell,” said study co-author Gun Semin, a professor at Koc University in Turkey.

    This is a fascinating finding because it not only means that happiness does have a scent, but that the scent is capable of transmitting the emotion to others. The study also found that other emotions, such as fear, seem to carry a scent too. This ensures previous research suggesting that some negative emotions have a smell, but it is the first time this has proved to be true of positive feelings.

    Researchers have yet to isolate(分离) exactly what the chemical compound for the happiness smell is, but you might imagine what the potential applications for such a finding could be. Happiness perfumes, for instance, could be invented. Scent therapies（香味疗法）could also be developed to help people through depression or anxiety.

    Perhaps the most surprising result of the study, however, is our broadened understanding of how emotions get communicated, and also how our own emotions are potentially managed through our social context and the emotional states of those around us. 

    The summer holidays are coming up. It's time to fill the bookshelves with quality literature for the kids. Here are some great books.

    Josephine Wants to Dance by Jackie French

    Price: $14.99 (for ages 4+)

    Josephine is a kangaroo who loves to dance. Her little brother, Joey, tells her that kangaroos don't dance; they jump. But Josephine continues to point her toes and leap through the air. When a ballet group comes to town and the lead ballerina (芭蕾舞演员) is injured, Josephine is called upon to help save the day. Can she do it, and, more importantly, does it matter that she's a kangaroo?

    House of Secrets by Chris Columbus

    Price: $19.99 (for ages 9+)

    The Walker kids —Caroline, Brendan and Nell—may have saved the world, but they can't save their home and must leave Kristoff House. Things can't get any worse, but then it turns out that the Wind Witch is still alive and planning an attack. To defeat her, the Walkers must return to the book world. The Walkers always help each other, but they must do it alone in their most important mission yet. And this time, if they fail, there's no chance of coming back.

    Edge of Extinction Book 1 by Laura Martin

    Price: $16.00 (for ages 9+)

    If you like The Land of the Dinosaurs, you will love this book. Two hundred years ago, the first dinosaur was successfully cloned (克隆). Soon after, humans realized they'd made a big mistake. Thirteen-year-old Sky Mundy's father suddenly disappeared five years ago. Along with her best friend， Shawn， she steps out into the world above --a world of dinosaurs --to look for him. Then she learns that everything she's been taught has been a lie.

    Does your local high school have a student newspaper? Only 1 in 8 of New York's public high schools has student newspapers – and many of those are published just a few times a year. A few more are online, which can leave out poorer schools.

    Rebecca Dwarka, an 18-year-old senior who works for her student paper said, “Facebook is the new way of finding out what happened. Nobody wants to actually sit down and read a whole article about it. This makes a 'whole article' sound a little like a long sentence in lonely places.”

    I am not nostalgic about high school student newspapers and never worked for mine. I put out what was then called a personal magazine with a group of friends because we wanted to write about peace, war and rock 'n' roll without school officials warning us not to make jokes about the local officials.

    School newspapers are in decline because students now find out what happened on social networking websites. This is a little discouraging because it proves that for millions of Americans, journalism is becoming a do-it-yourself thing. Every citizen can be a reporter.

    When something happens, we look for social media messages. Facebook posts and Tweets have become the means by which citizens and reporters can prove, deny, pass on stories and express opinions without the press' challenging, researching or slowing the message.

    But truly good journalism is a craft, not just a blog post. It requires seeing something carefully and it uses an eye for details to help prove a larger view. And even journalism that conveys an opinion tries to be fair. If school newspapers begin to disappear, I hope there are other ways for students to learn that.

    Yesterday I cleared up my house and I mean really cleared up my house. The room that gave the most results was my husband's "office". There I found: one right-footed shoe, size 10 (he lost the other one somewhere), a set of Star Wars videos and two small china cats someone gave me last birthday. I collected these "finds" and took them downstairs and logged (登录）on to eBay: the answer to all our rubbish.

    What is eBay? It aims to provide a global trading platform where almost anyone can trade almost anything. The idea came from Pierre Omidyar. Born in Paris, Omidyar moved to Washington when he was still a child. At High School he became very interested in computer programming and after graduating from Tufts University in 1988, he worked for the next few years as a computer engineer. In his free time he started eBay as a kind of hobby, originally offering the service free by word of mouth. By 1996 there was so much traffic on the site that he had to upgrade and he began collecting fees. Joined by a friend, Peter Skoll and in 1998 by his dynamic CEO, Meg Whitman, he has never looked back. Even in the great dot-com crashes of the late 1990s eBay went from strength to strength. It is now one of the ten most visited online shopping sites on the Internet.

    If you think about it, it's a perfect Internet idea. All you have to do is take an e-photo, write a description, fill out a sales form and you're in business; the world is your market place.

    Some of the more bizarre goods up for offer have been a piece of French bread, partially eaten by Justin Timberlake, advertising space on a man's head, and a pair of used false teeth.

    One week later I am proud of having a clean and tidy home and € 110 in cash. Someone even bought the shoe.

    For thousands of years, people have known that the best way to understand a concept is to explain it to someone else. "While we teach, we learn," said Roman philosopher Seneca. Now scientists are bringing this ancient wisdom up to date. They're documenting why teaching is such a fruitful w ay to learn, and designing creative ways for young people to take part in instruction.

    Researchers have found that students who sign up to tutor others work harder to understand the material, recall it more accurately and apply it more effectively. Student teachers score higher on tests than pupils who're learning only for their own sake. But how can children, still learning themselves, teach others? One answer: They can tutor younger kids. Some studies have found that first-born children are more intelligent than their later-born siblings(兄弟姐妹). This suggests their higher IQs result from the time they spend teaching their siblings. Now educators are experimenting with ways to apply this model to academic subjects. They arrange college undergraduates to teach computer science to high school students, who in turn instruct middle school students on the topic.

    But the most cutting-edge tool under development is the "teachable agent" — a computerized character who learns, tries, makes mistakes and asks questions just like a real-world pupil.

    Computer scientists have created an animated(动画的)figure called Betty's Brain, who has been "taught" about environmental science by hundreds of middle school students. Student teachers are inspired to help Betty master certain materials. While preparing to teach, they organize their know ledge and improve their own understanding. And as they explain the information to it, they identify problems in their own thinking.

    Feedback from the teachable agents further improves the tutors' learning. The agents' questions forces student tutors to think and explain the materials in different ways, and watching the agent solve problems allow s them to see their know ledge put into action.

    Above all, it's the emotions one experiences in teaching that improve learning. Student tutors feel upset when their teachable agents fail, but happy when these virtual pupils succeed as they develop pride and satisfaction from someone else's accomplishment.