It could happen just about any time you step out in public. You get onto an almost-empty bus, but the next passenger in decides to ignore dozens of empty seats to sit right next to you. While you're waiting in line at a supermarket, the next customer insists on standing only two inches behind you and shouting into his cell-phone. You go into a public restroom, and the next person to enter decides to use the next stall. Transgressions(冒犯) like these don't just make us feel uncomfortable; we often feel anxious, alarmed; and violated(被侵犯的). It is the attack of the personal-space invaders.

    In any society, shared definitions of personal space govern how we interact with other people. People living in densely(密集地) populated cities like Mumbai, Beijing, or Mexico City tend to require less personal space than people living in sparsely(稀少地) populated places within the country. In America, New Yorkers often have smaller requirements than residents of western states, like Montana, Shenandoah and Wyoming. Because everyone has different standards, gestures that are innocent in one place can be interpreted as opposite in another, especially in Britain.

    As the British etiquette(礼仪) website Debrett puts it, as a British person, somebody standing too close may make you "focus less on what somebody is saying than on how close they are to you". Simple acts like putting an arm around someone you don't know may seem friendly in China, but they can make us very uncomfortable. People from many European countries such as France and Spain kiss each other on the cheek when they meet, yet to British person, this seems too friendly and "touch-freely". The website explains! "The British are not backslappers(拍人后背的人) and generally do not show affection in public".

    Are British people unfriendly? Far from it. The website adds that they are not as "stand-offish and aloof' as they may seem, but very friendly and helpful to foreigners. However, remember not to be too close. If you are going to come closer than an arm's length, please let them know.

    Scientists have been studying how people use money for long. Now they're finding some theories may apply to one group of monkeys.

    Researchers recently taught six monkeys how to use money. They gave the monkeys small metal disks(圆片) that could be used like cash and showed them some yummy apple pieces. The monkeys soon figured out that if they gave one of the disks to a scientist, they'd receive a piece of apple in return.

    If you think that is all the monkeys can figure out, you are wrong. Two researchers, Jake and Allison, acted as apple sellers in the experiments. The monkeys were tested one at a time and had 12 disks to spend in each experiment. Jake always showed the monkeys one apple piece, while Allison always showed two pieces. But that's not necessarily what they gave the monkeys. The number of apple pieces given for a disk was determined at random.

    Experiment One: Allison showed two pieces of apples but gave both pieces only half the time. The other half, she took one piece away and gave the monkey just the remaining piece. Jake, on the other hand, always gave exactly what he showed: one piece for each disk. The monkeys chose to trade more with Allison.

    Experiment Two: Allison continued to sometimes gave two pieces and sometimes one piece. But now, half the time, Jake gave the one apple piece he was showing, and half the time he added a bonus. Guess what? The monkeys chose to trade more with Jake.

    In the first experiment, the monkeys correctly figured out that if they traded with Allison, they'd end up with more treats. In the second one, when a monkey received two pieces from Jake, it seemed like again. When Allison gave the monkey only one piece instead of the two she showed, it seemed like a loss. The monkeys preferred trading with Jake because they'd rather take a chance of seeming to win than seeming to lose.

    We also sometimes make silly business decisions just to avoid the feeling that we're getting less, even when were not. Would you have made the same choices?

    Running is often tiring and a lot of hard work, but nothing beats the feeling you get after finishing a long workout around the track.

    But while it's long been believed that endorphins (脑内啡）—chemicals in the body that cause happiness — are behind the so-called “runner's high”，a study suggested that there may be more to this phenomenon than we previously knew.

    According to a recent study published by a group of scientists from several German universities, a group of chemicals called endocannabinoids (内源性大麻素）may actually be responsible for this familiar great feeling.

    To test this theory, the scientists turned to mice.

    Both mice and humans release high levels of endorphins and endocannabinoids after exercise, along with many other chemicals. After exercising on running wheels, the mice seemed happy and relaxed and displayed no signs of anxiety.

    But after being given a drug to block their endorphins the change. However, when their endocannabinoids were block with a different drug, their runner's high symptoms seemed to fade.

    “The long-held notion of endorphins being responsible for the runner's high is false. Endorphins are effective pain relievers, but only when it comes to the pain in your body and muscles you feel after working out,”Patrick Lucas Austin wrote on science blog Lifchacker.

    Similar studies are yet to be carried out on humans, but it's already well known that exercise is a highly effective way to get rid of stress or anxiety.

    The UK's National Health Service even prescribes (开药方)exercise to patients who are suffering from depression.

    “Being depressed can leave you feeling low in energy, which might put you off being more active. Regular exercise can boost your mood if you have depression, and it's especially useful for people with mild to moderate (中等的）depression,” it wrote on its website.

    It seems like nothing can beat that feeling we get after a good workout, even if we don t fully understand where it comes from. At least if we're feeling down, we know that all we have to do is put on our running shoes.

    The possibility of self-driving robot cars has often seemed like a futurist's dream, years away from coming into reality in the real world. Well, the future is apparently now. The California Department of Motor Vehicles began giving permits in April for companies to test truly self-driving cars on public roads. The state also cleared the way for companies to sell or rent out self-driving cars, and for companies to operate driverless taxi services. California, it should be noted, isn't leading the way here. Companies have been testing their cars in cities across the country. It's hard to predict when driverless cars will be everywhere on our roads. But however long it takes, the technology may change our transportation systems and our cities, for better or for worse, depending on how the transformation is managed.

    While much of the debate so far has been focused on the safety of driverless cars, policymakers should be talking more about how self-driving cars can help reduce traffic jams, cut emissions(排放)and offer more convenient and affordable choices to move around. The arrival of driverless cars is a chance to make sure that those cars are environmentally friendly and more shared.

    Do we want to copy or even worsen the traffic of today with driverless cars? Imagine a future where most adults own their self-driving cars. They accept long, slow journeys to and from work on crowded highways because they can work, entertain themselves or sleep on the ride. They take their driverless car to a date and set the empty car to circle the building to avoid paying for parking. Instead of walking a few blocks to pick up a child or the dry cleaning, they send the self-driving minibus. The convenience even leads fewer people to take public transport — an unwelcome side effect researchers have already found in ride-hailing(网约车)services. Policymakers should start thinking now about how to make sure the appearance of driverless cars doesn't worsen the transportation system we have today. The coming technological development presents a chance for cities and states to develop transportation systems designed to move more people, and more affordably. The car of the future is coming. We just have to plan for it.

    Imagine on your way out of class today you trip (绊倒) on a loose piece of carpet and twist your ankle. As a result of the injury, you lose your place in the local sports team, and have to miss an important job interview. Bad luck? Or an opportunity to get rich quick?

    Perhaps it's not surprising that Roslyn Darch of Houston, Texas, USA felt annoyed when she tripped over a toddler (学步的儿童) running around a furniture store, and broke her ankle. But a few months later, she was $780,000 richer after she successfully sued (起诉) the shop. The owners were clearly surprised at the size of Roslyn's payout, particularly since the toddler she tripped over was her own son.

    And it's not only claims for physical injuries that are keeping the lawyers busy. A group of overweight New York teenagers sued a giant fast-food company claiming that they had not had enough warning that a diet of burgers, fries and milk shakes would make them fat. The parents of one nineteen-year-old English schoolgirl successfully sued her school for 42,000 compensation when she failed to get a top grade in a university entrance exam. Sandra York received $113,000 from a Washington D.C. restaurant after slipping on a spilt soft drink.

    Who knows where it will end? Some say there should be penalties (处罚) for excessive (过度的) claims, or that there should be a limit on payouts. But one thing's for sure—in the end, the only certain winner is the lawyer!

    A crew of six teenage girls completed a nine-day sailing trip in the US recently, after braving seasickness and strong winds.

    For the past three years, the Sea Cadet teenagers who set sail were all male. Roger Noakes, who captained the boat, said this was the first time he'd taken out an all-female crew.

    The girls asked for an all-girls trip in August this year. The crew set sail along with three adults, Noakes and two Sea Cadet representatives. The original plan was for the girls to sail 24 hours a day in rotating shifts(轮流换班)along the coast and then return. Things turned out differently, however. “The first night was rough because the wind was really hard. The waves were going up and down,” said Abby Fairchild, 16. “Everybody got seasick.” Noakes gave the girls the option of just sailing in the bay and not going into open water. “But they decided they were going.”

    The teenagers then sailed a long way overnight and slept in shifts. “We've learned everything from steering(掌舵)the boat itself to putting up the sails to cooking while we have rough seas, ” said 15-year-old Olivia Wilcox.

    The teenagers stopped on land in Massachusetts. They didn't make it to their original destination in Maine, where they were supposed to have a celebratory dinner, due to the weather and winds. They said they weren't disappointed, however, as they'd learned a lot. “They learned about boating, and above all, they built confidence and character,” said Noakes.