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.

    With the development of modern science and technology, the functions of cellphones have changed greatly. {#blank#}1{#/blank#}The only difference may be that they fit in your pocket and you pay by the minute to use them. Some of the things a cellphone can do for you will be available this year:

Surf at speed

    Cellphones that let you use the Web have been around for years. So, what's new? Well ,  faster third-generation (3G)  networks that let you surf at anywhere. {#blank#}2{#/blank#}Possible choices are from IJG Electronics VX 8000 and Motorola V1150.Listen as you go.

    {#blank#}3{#/blank#} There is no doubt that it is about to change. Sony Ericsson's new W8001 can hold around 150 songs in its 500 MB memory. And Samsung's SPH-V5400 even comes with a l. 5 GB hard drive. Mobile phones may eventually replace miniMP3 players, especially for teens. Say cheese.

    Camera cellphones are not new either but most of them have limitations: around l- megapixel  (百万像素 ) .  However new technology has made 2-megapixel units more common ,and 3-megapixel units are showing up soon. Some 2-megapixel models, like Sony Ericsson's K7501, offer limited zoom and focus controls.   {#blank#}4{#/blank#}Portable TV.

    You say you like "watching TV"? That's what Samsung MMA700 wants to give you. The new model lets users watch popular TV programmes~ for a fee. Other choices are Nokia's 6620, Sanyo's MM740 and NEC's N940. {#blank#}5{#/blank#}

    The above are just a handful of what you ' ll see in the coming months.  Further down the road, your mobile phone may play a host of other roles, such as mobile credit card, position locator and so on. So what is there that a cellphone can't do?

A. The NEC model lets you watch public TV - no fee.

B. Without a cellphone, you can do nothing in your daily life.

C. Nowadays, new cellphones are much cheaper than old ones.

D. Today's do-it-all mobiles have a lot in common with the computer.

E. This then allows a carrier to send video, music, and games to your phone.

F. Others, like LG's recent A7110, can even capture 30 minutes of full-motion video.

G. The problem with most cellphone MP3 players is that they hold only a handful of songs.

Do you think you would work out more if you were offered money to do so? Science has shown that money can give people motivation to work out, but perhaps not in the way that you think.

According to a study published in the Annals of Internal Medicine Journal, the best strategy isn't offering money; it's giving someone money, then threatening to take it away.

Researchers gave 281 people the goal of walking 7,000 steps every day over 13 weeks.

To motivate the people who took part to reach the goal, researchers divided them into three groups.

People in the first group received $1.40(9 yuan) each day as long as they finished 7,000 steps, the second group was only able to collect the $1.40 if they had reached 7,000 steps the day before, and the third group was given $42 at the beginning of each month and $1.40 was taken away every time someone failed to meet the goal.

The third group met their daily fitness goals 50 percent more often than the other two groups, showing that people were most motivated to walk by the fear of losing money.

    “People are more motivated by losses than gains, and they like immediate gratification.” study author Dr Mitesh Patel, an assistant professor at the University of Pennsylvania in the US, told CNN. “They want to be rewarded today, not next year or far into the future.”

    Our brains tend to avoid wanting to lose things more than they try to get the benefits from gaining them, Patel explained. “It makes people think like the money is theirs to lose from day one.”

In addition, in most programs, many participants will drop out quickly and only the motivated will stay involved, Patel said.

    “In ours, we were pleasantly surprised that 96 percent stayed.” he added.

The study provides evidence that what matters is not only the money incentive （激励）, but also how you think about them. This is important to how effective they are. The evidence could have a big effect on health promotion programs in the future, according to the study.

“Incentives themselves are not all you need,” Stephanie Pronk, a health and wellness consultant with the Aonplc corporation, told The Wall Street Journal. “It's really important to change up the incentive design and keep people on their toes.”

    The vast majority of us spend our entire lives pulled down by gravity. Then there are astronauts.

This small population of space travelers has given researchers a rare look at what happens to the human body when it's able to spend large amounts of time outside the downward pull of the Earth. This week, a study on one of the largest groups of astronauts yet —34 participants—was published in The New England Journal of Medicine.

    In the new study, a team of international radiologists supported by NASA looked at MRIs of the brains of astronauts before and after their trips to space. The scientists found that upon returning to Earth, many of the astronauts' brains had become repositioned inside their skulls, floating higher than before. In addition, the space between certain brain areas appeared to have shrunk. The changes were more common in astronauts who took longer trips into space.

    The team characterized astronaut trips as short (an average of less than 14 days) or long (an average of about 165 days). Radiologists who didn't know each astronaut's duration（持续时间）in space compared MRIs from before and after their trips.

    Of the 34 total astronauts involved in the study, 18 took long trips to space—spending most of that time on the International Space Station —and of those, 17 returned to Earth with smaller areas between the frontal lobe（脑前额叶）and parietal lobe（顶叶）. The same area of the brain also shrank for three of the 16 astronauts who took shorter trips with the US Space Shuttle Program. The researchers also found that 12 of the ISS astronauts and six of the space-shuttle astronauts returned home with their brains sitting slightly higher in their skulls than before.

    It's not clear what, if anything, these brain changes mean for the health of space travelers. In general, it appears the human body tolerates space travel fairly well: the time astronauts have spent in zero-gravity environments so far doesn't seem to have had any strong or long-lasting effects.

    My first week in the United States was a cultural shock. Everything felt new to me, including the style of conversation, the community I lived in and even the type of food people ate.

    In our community back home, people eat mutton and chicken. Pork and beef are also common among other communities, but eating beef is taken as an illegal act. Unlike Nepal, eating beef is common in the West where most of the people follow religions other than Hinduism.

    Food is just an example. When people move from one part of the world to another, they should adapt（适应）themselves to the new culture. For example, going to the bars or getting drunk is not acceptable in my community, but it is common in the US after a certain age.

    I was raised in a traditional Hindu family in Nepal. We have a conservative（保守的，谨慎的）opinion towards marriage. Arranged marriages（包办婚姻）are common in which families decide whether the two should get married. Free love marriages are not allowed and are seldom seen. Same-sex marriage is also considered impossible.

    To me, culture is a matter of habit. The culture is so deep-rooted in people's minds that most people are against changes. It is always easy for them to do what they have been doing throughout their life. It may be difficult for anyone to adapt to a new culture.

    However, with travel being an unavoidable thing for modern people, one always comes across different cultures. In such cases, one should be respectful and adaptive to the culture other people follow. The world is always a better place to live in when we have spaces for people of all cultures.

    Engineers have put a huge garbage collector to gather plastic material in the Pacific Ocean between California and Hawaii, the world's largest spread of garbage, twice the size of the state of Texas.

    The Ocean Cleanup organization created the collector. The group's founder, Boyan Slat, an inventor born in 1994, was just 16 when he was moved to clean up the oceans when he was on a dive and saw more plastic bags than fish

    Last Saturday, a ship pulling the pipe-shaped floating barrier left San Francisco. Attached to it is a screening skirt that hangs three meters down in the water. The screen is designed to collect the plastic as it moves through the water. Sea animals can safely swim under the barrier.

    The cleanup system also comes with lights powered by the sun, cameras, and other special devices, so the system can communicate its position at all times. That way a support ship can find it every few months to remove the plastic that has been collected.

    Shipping containers will hold all the plastic gathered, including bottles and fishing equipment and are expected to be back on land within a year. Then the plastic will be recycled. The free-floating barriers are made to survive extreme weather conditions and damage from continual use. They will stay in the water for twenty years, thus collecting 90% of the garbage in the area.

    The Ocean Cleanup has received $ 35 million in donations to pay for the project, hoping to put 60 free-floating barriers in the Pacific Ocean by 2020. "It's important to turn off the taps on plastic entering the ocean, but I also think people can do more than one thing at a time to deal with this problem," Slat said.