The sound of a mosquito can mean trouble in many parts of the world. The bite of the mosquito can be deadly. The insects carry serious diseases like malaria (疟疾). It is estimated that almost 630,000 people died from malaria and malaria­related causes in 2012, and most of these cases were in African countries.

    In the United States, a group of California scientists are working to develop a more effective and less costly substance (物质) to protect people from mosquitoes. The researchers are investigating the sense of smell in mosquitoes. They found the insects use the same receptor for identifying carbon dioxide in human breath as they do for the smell of our skin. Anandasankar Ray, who is leading the investigation, says scientists tested more than a million chemical compounds (化合物) until they found a substance called Ethyl Pyruvate. He says Ethyl Pyruvate makes the mosquitoes' receptors inactive. “When we apply Ethyl Pyruvate to a human arm and offer it to hungry mosquitoes in a cage, very few of the mosquitoes are attracted to the human arm because only a few of them are able to smell it out,” said Ray.

    Genevieve Tauxe, a member of the research team, says it was not easy to find the neurons (神经元) of noble cells that recognize both the smell of human breath and skin. “With the device used to examine the mosquito, we are able to insert a very small electrode (电极) into the part of the mosquito's nose, where its smelling neurons are and where the smell is happening,” said Tauxe.

    Anandasankar Ray says a product based on Ethyl Pyruvate may cost less to produce than DEFT, the most effective chemical treatment now in use. He says DEFT is too costly for most people who live in areas affected by malaria.

    “Perhaps by finding smells that can attack other target receptors, we will be able to improve upon DEFT and finally have the next generation of insect behaviour control products,” said Ray.

    Welcome to the home page of the Photography World website. We offer a range of useful services for photographers and photography lovers.

    Camera Club

    Join our club and enjoy a range of benefits. You'll get invitations to our regular events, such as members' film shows, exhibitions and talks by experts. You can apply for Full membership, Associate membership or Junior membership. Full membership includes free entry to all events and 10% discount when ordering equipment online. Associate membership gives you half-price tickets to events. Junior membership (proof of age required) allows youngsters to enjoy the benefits of Full membership. Costs (per year)：Full membership 20, Associate 12, Junior 10. Most new members joined as the result of recommendations from current members.

    Advice Center

    Take advantage of our Advice Center. Ask our panel of experts your questions about cameras and photography. Whether you're looking for solutions to problems or fresh ideas for interesting photos, you'll get response here. Simply email your questions to advice@cameraclub.com or leave a recorded message on 0800-565656. We guarantee to send you a reply by email within five days. Please note that since we can't provide information about repairs to cameras, you should contact the manufacturer about these.

    Competition

    Our competition is held every year and is a great chance for new and experienced photographers to win one of our great prizes, which range from albums to keep your photos in to one-day courses or a set of state-of-the-art camera equipment. Entries can only be accepted from members. They can be sent in prints, on a CD or memory stick, or by email. Please note that photos can't be returned, so make sure you have copies. The topic — for example, wildlife,     transport, people — is announced each year here on the website when the competition opens.

    Rembrandt Harmenszoon van Rijn was one of the greatest artists of all time. He was born on July 15, 1606, in Leiden, Holland. Rembrandt began painting at an early age. At the age of 15, he traveled to Amsterdam to study art. But he soon returned home to paint on his own.

    Rembrandt's first paintings were of subjects from history. He used bright colors and shiny paints. These paintings were popular. Rembrandt became well-known in his community.

    In 1628, Rembrandt began to teach art. He was a respected teacher with many students. In 1632, Rembrandt again moved to Amsterdam. He began painting portraits (肖像) of many well-known people in Amsterdam. He soon became famous in Holland for his beautiful portraits.

    In 1634, he married a wealthy and educated girl named Saskia. She served as a model for many of his paintings. They moved into a large home where Rembrandt hung many of the paintings that he had collected. He enjoyed buying paintings by other artists.

    Rembrandt continued to succeed as an artist. But tragedy (悲剧) began to strike his family. Three of his four children died at a very early age. His wife, Saskia, died in 1642.

    Rembrandt became very sad. He began to paint with darker colors. But somehow, his painting grew even more beautiful. He used dark colors around the figures in his paintings. The figures themselves were painted as if a soft light were shining on them. One of Rembrandt's most famous paintings, The Night Watch, is from this period.

    Rembrandt began to paint more for himself and less for other people. Although his work was excellent, he was not able to make enough money to keep his house.

    Until he died on October 4, 1669, Rembrandt continued to paint. Rembrandt created over 600 paintings, 300 etchings (蚀刻画), and 1,400 drawings. Some of his most fascinating paintings were the portraits that he painted of himself. About 100 self-portraits leave a great record of his lifetime.

    San Francisco is a great city. Below are some ideas for educational activities and programs in San Francisco for this summer.

    The San Francisco School: Summer Programs

    There are summer camps for the children from pre-kindergarten through middle school at the San Francisco School. With programs such as "Fearless Writing" "A Green World" and "Re-Making Clothing", San Francisco becomes a great place for children to learn and have fun in the summer. Registration starts in the spring. Call 415-749-4550 to know more.

    San Francisco Art Institute: Community Education

    From children to elders, all people are welcome to sign up for all sorts of art classes all year round, such as "Adult Continuing Education", "Pre-college Programs" and "A Young Artist". Check online for schedules, class types, age groups and more or call 415-749-4500.

    San Francisco University High School: Summer Program

    This is a three-summer commitment and a great program preparing kids for college. It provides language and art classes in the morning and social studies such as sports and history in the afternoon. There are also fun activities such as a field day, a party night, a talent show, etc. 30 to 35 tenth-grade children are chosen each summer, so you have to fill out a form. Call 415-749-4558 to know more.

    Rudolf Steiner College: Summer Programs

    Rudolf Steiner has summer programs for those who want to take courses such as teaching grade courses 1 to 8. Registration is at the beginning of April. Call 415-749-4560 for more about it.

    These activities and programs are usually popular, and if you are interested, get up and join us!

    No one knows how much money Dr. Lyle Tullis gave away to students. I was his colleague for nearly a decade and I never stopped being amazed at his generosity. Our college has a program of providing cross-cultural experiences for students. Lots of students take advantage of summer experiences oversea. I discovered that no group left for overseas without some of its members receiving financial help from Dr. Tullis.

    It wasn't that he made a lot of money. For one thing, he taught in a church-run school. There, his salary (薪水) was half of what those people earned in a tax-supported school.

    Other colleagues occasionally complained about the low pay. Not Lyle Tullis. Occasionally some professors would leave our campus for a better-paid position. They told me they did so because, with better pay, they could provide for their families.

    The size of Lyle Tullis' paycheck never seemed to be the most important thing to him. I realized that one day when I was thanking him for helping a student, his eyes shone as he said to me, "I've got so much money that I don't know what to do with it. So, I just give it away."

    Most people wouldn't have thought that way. Dr. Tullis drove one of the oldest cars on campus. It was even older than almost any of the students' cars. His home, while comfortable, was not fancy at all. But Lyle Tullis lived with the feeling that he had so much money that he needed to give it away.

    He was one of the favorite on campus. Cynics (愤世嫉俗) might say he bought fame. But they would misunderstand. Lyle wanted to devote his life, all of it, to helping others.

    The European Union(EU) is an organization of European countries. The countries are independent and are governed in different ways. In the United Kingdom, for example, the head of state is a king or queen. In France, on the other hand, the head of state is a president. But each of them sends representatives(代表)to European Parliament, which has some control over what happens in each of the member countries.

    The idea of the EU began in the 1950s. The first members were France, Germany, Belgium, Luxembourg, the Netherlands and Italy. Little by little, the number increased during second half of the twentieth century. By the year 2000, there were 15 member countries. The new countries were Austria, Denmark, Finland, Greece, Ireland, Portugal, Spain, Sweden and the United Kingdom.

    In 2004, the EU increased to 25 members. The Czech Republic, Estonia, Hungary, Latvia, Lithuania, Poland, the Slovak Republic and Slovenia, plus the Mediterranean islands of Cyprus and Malta all became members. The expanded EU has a population of more than half a billion people, twice as big as the population of the US.