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.

    In Washington, Virginia and Maryland, the final months of the year have many festivals. Whether you are into a theatre environment, medieval times or a book festival, there is an event for you.

1). Maryland Renaissance Festival

    The festival, now in its 38th season, features 12 stages and hundreds of costumed actors offering entertainment such as music and theatre performance, sword swallowing and a human chess match. Sept. 21 through Oct.19.

2). Baltimore Book Festival in Maryland

    This three-day fair features talks and book signings from more than 275 locally and nationally known authors, including Alice McDermott and Andre Dubus III. The festival also includes live music and literary hands-on projects for kids. Sept. 26-28.

3). Middleburg Film Festival in Virginia

    The festival offers a relaxed theatre environment, and the events include a dancing party, an orchestra performance of horror film music by Marco Beltrami, and a discussion with Colleen Atwood, who is a famous costume designer. Oct. 30 through Nov.2.

4). Temple Hall Corn Maize and Fall Festival in Virginia

    The 286-acre farm offers a lot of family-friendly entertainment, including pig races, farm animals and camel rides. Grab seasonal goods at the farmers' market, take part in the corn harvest, and hear live bluegrass and folk music. Friday through Sunday, Sept. 26 through Nov.2.

5). Kids Euro Festival in Washington

    Here is a chance to celebrate and experience European arts and Culture, no passports required. Twenty-eight European countries will be represented during the multicultural children's event, which features more than 200 performances and workshops. The festival is for children ages 2 through 12, librarians and educators. Activities include puppet shows, cooking and theatre workshops. “It really brings Europe to the children, ” said organizer Sandi Auman. Oct. 24 through Nov. 9

    When you sit down, you pick it out. When you are in your car, you reach for it．When you're at work, you take a break to have a moment alone with it. When you get into a lift, you play with it．

    Cigarettes? Cup of coffee? No, it's the third most addictive thing in modern life, the cell phone．And experts say it is becoming more difficult for many people to curb their desire to hug it more tightly than most of their personal relationships．

    With its shiny surface, its smooth and satisfying touch, its air of complexity, the cell phone  connects us to the world even as it disconnects us from people three feet away．In just the past  couple of years, the cell phone has challenged individuals, employers, phone makers and  counselors（顾问）in ways its inventors in the late 1940s never imagined．

    The costs are becoming even more evident, and I don't mean just the monthly bill．Dr．Chris  Knippers, a counselor at the Betty Ford Center in Southern California, reports that the overuse of  cell phones has become a social problem not much different from other harmful addictions: a barrier to one-on-one personal contact, and an escape from reality．

    Sounds extreme, but we've all witnessed the evidence: the person at a restaurant who talks on the phone through an entire meal, ignoring his kids around the table; the woman who talks on the phone in the car, ignoring her husband; the teen who texts messages all the way home from school, avoiding contact with kids all around him．

    Is it just rude, or is it a kind of unhealthiness? And pardon me, but how is this improving the quality of life?

    Jim Williams, an industrial sociologist based in Massachusetts, notes that cell-phone addiction is part of a set of symptoms in a widening gulf of personal separation．He points to a study by Duke University researchers that found one-quarter of Americans say they have no one to discuss their most important personal business with．Despite the growing use of phones, e-mail and instant messaging, in other words, Williams says studies show that we don't have as many friends as our parents. “Just as more information has led to less wisdom, more acquaintances via the Internet and cell phones have produced fewer friends,” he says．

    If the cell phone has truly had these effects, it's because it has become very widespread．Consider that in 1987, there were only 1 million cell phones in use．Today, something like 300 million Americans carry them．They far outnumber wired phones in the United States．

    How often do you let other people like a bad driver, a rude waiter, or an angry boss, change your mood?

    Sixteen years ago I learned a lesson. I got in a taxi, and we took off for Grand Central Station. We were driving in the right lane when all of a sudden, a black car jumped out of a parking space right in front of us. My taxi driver used his brakes, the tires made a loud noise, and at the very last moment our car stopped just 3cm from the back of the other car.

    I couldn't believe it. But then I couldn't believe what happened next. The driver of the other car, the guy who almost caused a big accident, turned his head around and he started shouting at us. I couldn't believe it!

    My taxi driver just smiled and waved at the guy. So, I said, “Why did you just do that? This guy could have killed us!” And this is when my taxi driver told me what I now call, “The Law of the Garbage Truck”. He said, “Many people are like garbage trucks. They run around full of garbage, full of anger and disappointment. As their garbage piles up, they look for a place to dump it. And if you let them, they'll dump it on you.”

    So I started thinking how often I let Garbage Trucks run right over me and how often I take their garbage and spread it to other people.

    I began to see Garbage Trucks. I see the load people are carrying. I see them coming to dump it. And like my taxi driver, I don't take it personally. I just smile, wave, wish them well, and move on.

    The meaning of the word "volunteer" may be a little different in different countries, but it usually means "one who offers his or her services". There are many different ways in which people can volunteer, such as taking care of sick people, working in homes for homeless children, and picking up garbage from beaches and parks. Volunteers may work within their own countries or in other countries. They are often people with a strong wish to help those who are less fortunate than themselves. Volunteer don't expect any kind of pay.

    At the root of volunteering is the idea that one person may have the ability to offer services that can help other people. Tracy, a good friend of mine, however, recently came back from India with a new idea of what being a volunteer means. She worked for two and a half weeks in one of Mother Teresa's homes in Calcutta. The following is her story.

    "I first heard about Mother Teresa in my high school. We watched a video about her work in India and all over the world. I was so moved by her spirit to help others and her endless love for every human being that after I graduated from high school, I also wanted to try her kind of work. So with two friends, I flew to Caltutta for a few weeks."

    "I was asked to work in a home for sick people. I helped wash clothes and sheets and passed out lunch. I also fed the people who were too weak to feed themselves and tried to cheer them up. I felt it was better to share with them than to think that I have helped them. To be honest, I don't think I was helping very much. It was then that I realized that I had not really come to help, but to learn about and experience another culture that helped improve my own understanding of life and the world."

    Many non-edible (不能吃的), poisonous or otherwise not pleasant-tasting butterflies have distinct colors and pat terns. As a result, other more palatable (可口的)butterflies have evolved to mimic (模仿)those patterns to avoid being consumed by predators. There are several types of mimicry in butterflies: Bayesian mimicry, Müllerian mimicry, wasp (黄蜂)mimicry and tiger complex mimicry. Birds will con­sume unpalatable butterflies and associate their colors and patterns with the negative experience, thus avoiding the but­terflies performing mimicry. It is possible that birds even communicate their experience with other birds.

    Bayesian mimicry was established by the naturalist Hen­ry Walter Bates in 1862. He first observed that mimicry involved a palatable butterfly resembling an unpalatable, often toxic (有毒的)，butterfly. This mimicry will only work when the toxic model species outnumbers the non-toxic spe­cies. He believed that mimicry was the result of edible but­terflies producing mutations (突变)making them resemble their inedible cousins. This in turn resulted in the increased survival of the butterflies containing the mutation and resul­ted in the similarities between species. In 1879 another naturalist, Johann Friedrich Theodor Müller, observed that in some cases of mimicry both the mimic and the model are un­palatable. He considered this to be a cooperative mimicry and believed the species evolved side by side in a mutually benefi­cial relationship. If a bird tried to eat a member of either spe­cies, it would then avoid both. Wasp mimicry is similar to Bayesian mimicry, but instead of mimicking another unpalata­ble butterfly species, the mimic resembles a wasp to avoid predators.

    The tiger complex is a group of around 200 species of Neotropical butterflies that are involved in the most well-known form of mimicry. It is named such because the patterns of all of the included species are black on a background of either orange or yellow, resembling a tiger. In the com­plex are many unpalatable species, a few toxic species and a large number of completely edible species. Members of the tiger complex are all known for congregating (集合)in large groups that would normally be easy food for birds. Fortunately, birds have no interest in them due to their mimicry.