Traffic problems are an everyday concern in many cities，including Washington，DC．A growing number of Washingtonians are turning to bicycles to get to and from work．In fact，the number of commuters who use bicycles has doubled in the city since 2007．

    Ralph Buehler teaches urban planning at the Virginia Polytechnic Institute and State University，popularly known as Virginia Tech．He has written a book about urban biking，calledCity Cyclin . g．He says there is a reason why urban bike tiding is now becoming more popular．

    “Over the last 60 to 70 years，cities in America have adapted to the automobile．”

    “Most cities took advantage of the money coming for the interstate highway system，from the federal government，  starting in 1956．There was a 90 percent federal match(补贴)so the cities only had to put up 10％．It was very tempting．”

    In the years after World War Two，many Americans moved to suburban communities，just outside major cities．They decided to travel great distances to and from work in exchange for a home in the suburbs．Their cars became a symbol of freedom．

    But today，many people believe they can save money by living in the city．

    Greg Billing is with the Washington Area Bicyclist Association．“When a person makes a change from using a car to using a bike，he／she is saving anywhere between 8 or $9，000 a year．”

    Ralph Buehler says governments save money when people use bicycles．“Building bicycling facilities is much cheaper than building and maintaining road facilities or public transport．”

    Washington，DC has also taken steps to protect bike riders．It approved a safe passing law and created areas on the road between cars and bikes．

    The United States Census Bureau says 4％of the city's workers ride to work by bike．The only city on the East Coast with more bike commuters is New York．

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    Pacific Science Center Guide

    Visit Pacific Science Center's Store

    Don't forget to stop by Pacific Science Center's Store while you are here to pick up a wonderful science activity or souvenir to remember your visit. The store is located(位于) upstairs in Building 3 right next to the Laser Dome.

    Hungry?

    Our exhibits will feed your mind, but what about your body? Our café offers a complete menu of lunch and snack options, in addition to seasonal specials. The café is located upstairs in Building 1 and is open daily until one hour before Pacific Science Center closes.

    Rental Information

    Lockers are available to store any belongings during your visit. The lockers are located in Building 1 near the Information Desk and in Building 3. Pushchairs and wheelchairs are available to rent at the Information Desk and Denny Way entrance. ID required.

    Support Pacific Science Center

    Since 1962, Pacific Science Center has been inspiring a passion(热情) for discovery and lifelong learning in science, math and technology. Today, Pacific Science Center serves more than 1.3 million people a year and brings inquiry-based science education to classrooms and community events all over Washington State. It's an amazing accomplishment and one we cannot achieve without generous support from individuals, corporations, and other social organizations. Visit pacificsciencecenter.org to find various ways you can support Pacific Science Center.

    If your dog looks pleased to see you—it is probably because it loves the particular way you smell.

    The scent (气味)of a familiar human apparently lingers like perfumein the animal's brain—where it causes an instinctive emotional response, research reveals.

    Our scent acts on a part of the canine (犬科的) brain associated with reward and the strongest reactions are produced by humans that pets know best, say scientists in America.

    Gregory Bern, of Emory University in Atlanta, said, “While we might expect that dogs should be highly tuned to the smell of other dogs, it seems that the 'reward response' is reserved for their humans. When humans smell the perfume of someone they love, they may have an immediate, emotional reaction that's not necessarily cognitive (认识的). So is it in dogs. But since dogs have a more sensitive smell than humans, their responses would likely be even more powerful than the ones we might have. In our experiment, however, the owners of the dog were not physically present. The canine brain responses were being caused by something distant in space and time. It shows that dogs' brains have these mental representations of us that persist when we're not there.”

    The experiment involved 12 dogs of various kinds by brain scans while five different scents were placed in front of them. The scent samples (样本)came from the subject (接受试险者) itself, a dog the subject had never met, a dog living in the subject's household. The familiar human scent samples were taken from someone else from the house other than the handlers during the experiment, so that none of the scent donors were physically present.

    The results showed all five scents gained a similar response in parts of the dogs brains involved in detecting smells. Responses were significantly stronger for the scent of familiar humans, followed by that of familiar dogs. The findings showed dogs reacted strongest to the scent of familiar humans even when they were not there. Pets trained as help or therapy dogs showed greater brain activity than the other dogs in the test.

    Researchers say the findings could improve the way to select animals helping wounded old soldiers or disabled people.

    Why do people lie? Many psychologists agree that it can start from childhood? There are various reasons why children make false statements. They usually tell untruthful stories to cover up the mistakes that they have done in the past. Lying is also a way to avoid receiving punishments from parents. If parents fail to reprimand their children for making up false stories, then there is a possibility that they will continue to lie during their teenage years.

    Teenagers lie because they want to be accepted by their friends. This is the main reason why they create stories that are not true just to become presentable and acceptable to other people. In some instances, teenagers tell untruthful statements to avoid criticisms from their families and friends.

    As teenagers grow, lying becomes one of your habits. Their knowledge on making up untruthful stories becomes more developed. People lie in workplaces if they fail to meet the deadlines and if they fail to accomplish and do their tasks efficiently. Some of the common lies made in workplaces are getting sick and having emergencies at home. The danger involved in frequent lying is when it, becomes a character. Frequent lying causes the development of the condition known to doctors as pathological（病态的）lying.

    Pathological lying is a mental health condition, which is associated with individuals who have the urge to tell untruthful statements. Patients suffering from it make up stories about everything and anything. These individuals lie to meet the standards of other people who they want to please. These patients deceive other people because it gives them an unexplained pleasure. One of the best ways of treating pathological liar is to help them tell true statements and stories at all times. This may be hard for them, but as they are accustomed to it, they will start to realize that they will be more accepted by their families and other people if they stop themselves from making up for stories

    One spring day, once the flowers have begun to open, a bee will hover (盘旋) and zip through your yard and dive-bomb your picnic table. While you're thinking about avoiding an attack, that bee is focused on something else entirely: me.

    A honeybee has about six weeks to live. Today, like most days, her task is to fly as many as three miles from home, stick her long, straw-like tongue into a hundred or so flowers. When the bee has had her fill, she'll fly home. There the bee will deposit what she has got into the mouth of one of her co-workers, who will relay it to another, and so on for about 20 minutes, until the mixture is ready to be placed into the comb. Then she and her 50 000 or so mates will hover in the dark all night every night, flapping their wings to create hot, breezy conditions to remove the water from the mixture. Several sunrises later, they will seal me off in a golden cell of beeswax. In her lifetime, our bee may visit 4,000 flowers, and yet will produce only one-twelfth of a tea spoon of me.

The average American consumes nearly a pound and a half of me every year, in tea, on toast, and beyond. If I do say so myself, I am a timeless treasure. Literally—I never go bad.

Alas, my good health is not guaranteed. The problem lies in the growth of industrial agriculture and the use of pest control chemicals, as well as changes in weather patterns, all of which reduce the number of flowers bees have to visit I'd appreciate your letting your own garden grow just a little wild My future depends on all of us fostering spring and summers wild flowers, thus helping the bees, who give so much—to you, to me—without ever asking for anything in return..

    Crossing your legs is an extremely common habit; most people don't even notice that they're doing it when they sit down. While you may find it comfortable to sit with one knee crossed over the other, it might be causing health problems that you are not aware of.

    A study published in Blood Pressure Monitoring stated that sitting with your legs crossed can increase your blood pressure. The reason this happens is because the blood in your legs has to work against gravity to be pumped back to your heart, crossing one leg over the other increases resistance, making it even harder for the blood to circulate. This causes your body to increase your blood pressure to push the blood back to the heart. You won't feel any immediate effects, but if you sit for long periods of time it's important that you take note of how long you have your legs crossed for. You shouldn't have your legs crossed for more than 15 minutes, and it's important that you get up and walk around at least once every hour.

    Crossing your legs can also lead to neck and back pain. Ideally, it's best for our bodies to sit with our feet planted flat, hip width apart, on the floor, but it's not easy to maintain perfect posture all day at the office.

    You also might notice that when you sit with your legs crossed for long periods of time your feet and legs get tingly(刺痛的) or have the feeling of being asleep. While the feeling of discomfort may only last a minute or two, repeatedly crossing your legs until they feel numb can cause permanent nerve damage.

    So next time you sit down, try to get yourself in the habit of sitting with both of your feet on the floor. Not only will it help your posture and stability, but it will also save your health in the long run.