You're rushing to work and a man ahead of you collapses (跌倒) on the sidewalk. Do you stop to help? In a study of by-standers, it was found that some people avert their gaze and keep on walking rather than stop and get involved. “There is a tendency to decide that no action is needed.” says a psychologist. “The first thoughts that pop into (进入) your mind often keep you from offering help. In order to take action, you have to work against them.” Here are some common thoughts that might prevent you from helping.

    Why should I be the one? I'm probably not the most competent (有能力的) person in this crowd. You might think someone older or with more medical knowledge should offer assistance (帮助).

    What if he doesn't really need my help? The fear of embarrassment is powerful; no one wants to risk looking foolish in front of others.

    No one else looks concerned-this must not be a problem. We can follow the people around us, but most  people tend to hold back their emotions in public.

     “If you spot (发现) trouble and find yourself explaining inaction, force yourself to stop and evaluate the situation instead of walking on,” says the psychologist. “Then retry to involve other people; you don't have to take on the entire responsibility of being helpful. Sometimes it's just a matter of turning to the person next to you and saying, “It looks like we should do something.” Or asking someone if an ambulance has been called and, if not, to call for one. Once you take action, most people will follow you.”

    It has been found that plastic that finds itself into UK's waters can find its way to the Arctic within just two years. UK researchers have used a current-tracking tool to follow the waste as it was carried by the waters of the northern hemisphere.

    The team at Imperial College London used PlasticAdrift.org to track ocean currents(洋流) and follow the trail of plastic north to the freezing Arctic waters. Their study revealed that the majority of plastic waste which didn't end up on the UK's coastline, or sink to the ocean floor, was carried through the Barents Sea, north of Norway, before being carried into the Arctic Ocean.

    Large pockets of the world's oceans are now choked with a soup of discarded plastics, made up of everything from shopping bags to old children's toys, brought to these trash “islands” by the currents. Over time larger chunks (厚块，大块) are broken down by the sun's ultraviolet rays (紫外线) and the saltwater, leaving plenty of micro plastics which can kill fish and other wildlife.

    Dr. Erik Van Sebille, a lecturer in oceanography (海洋学) and climate change at Imperial, said, “We're only just beginning to understand the effect that plastic waste has on the weak Arctic ecosystem(生态系统), but we know enough about the damage done by oceanic plastic pollution to act and reduce its impact on our oceans and coastlines. From seabirds caught in loops of plastic packaging to polystyrene particles(聚苯乙烯粒子) blocking the digestive(消化的) systems of fish, plastic causes a continuous path of destruction from surface to seafloor. This analysis shows how in the UK we're part of the problem.”

    Dr. Erik continued, “It would be impossible to ban plastic, and undesirable as it is, it's a useful material that offers many benefits. We should instead have a holistic (整体的) approach to improving the situation, including social and behavioral, chemical and engineering solutions. Our aim is to have the least amount of plastic that ends up in the oceans and make sure it degrades (降解) quickly and safely if it does. ”

    Philadelphia offers a ton of attractions that are suitable for people of every age and here are some family—friendly attractions.

    Spruce Street Harbor Park

    Spruce Street Harbor Park, one of the best urban beaches in America, is an outdoor heaven on the Delaware River waterfront. Visitors can relax in a hammock, play on the playgrounds, and play games like table tennis and giant chess. Don't miss out on the park at night, when colorful LED lights hanging from treetops make the entire area bright.

    Blue Cross River Rink

    Offering ice skating in the winter and roller skating in the summer, Blue Cross River Rink creates a fun, outdoor experience for the whole family. Visitors can play on the nine-hole mini-golf course during the summer, and enjoy eats and drinks from the on-site(现场的)bar and restaurant all year round.

    Sesame Place

    Big Bird, Elmo and the other stars of Sesame Street come out and play at Sesame Place, the only theme park in the nation starring the popular TV show's most lovable characters. A water park, interactive activities, parades, fireworks and shows add to the fun.

    Once Upon a Nation Storytelling Benches

    On summer days, uniformed and professional storytellers at 13 storytelling benches throughout Philadelphia's Historic District entertain visitors with true, free, three-to-five minute tales about the colonial(殖民的)era as part of Once Upon a Nation. Children can pick up a Story Flag at any storytelling bench, and then collect a star from every storyteller on their journeys. Flags with all the stars can get free rides on the Parx Liberty Carousel at Franklin Square.

    A year back I received a full scholarship (奖学金) to attend the University of San Francisco. All of my hard work paid off. My mom had spent a lot on my attending a private high school, so I made sure to push myself: I volunteered, took part in various clubs, and graduated with honors. I was so excited to start a new part of my life.

    Soon enough, the big day came, but it wasn't like what I had thought. The first two weeks were the most difficult days of my entire life. Every night I would cry myself to sleep. I was missing my family, my home and everything in my hometown so much and I didn't know how to deal with my broken heart.

    To distract myself, I threw myself into my studies. I also found a ton of jobs. In any free time, I started forcing myself to go to the gym. I wanted to keep every part of my day busy so I wouldn't think about how lonely I felt. Soon after, I began to control my eating, considering it another solution to my homesickness(想家). But soon there was something wrong with me.

    Finally, I went to see a doctor. When the doctor told me I had no choice but to take time away from school, I started to fear. How could I stop? School was what I was best at. "I'm not so bad," I thought in my head. But the result was that I was taken to hospital again a month later and my mother came heartbrokenly. I had to take a semester off from school, and go to the treatment center near my home.

    If there are girls who are suffering similarly, I hope you know that there is hope and that you should have a positive attitude towards life. Though you may feel alone, there are so many people who can understand your struggle. That's why I want to share my story.

    Thanks to this new hands- free suitcase, carrying around heavy luggage may soon become a thing of the past. Designed by Israeli company NUA Robotics, this "smart" suitcase can follow you everywhere you go.

    The carry­on suitcase, now a prototype(雏形), connects to a smartphone app via bluetooth. It has a built­in camera sensor that can "see" you and follow you around on flat floors. It comes with an anti­theft alarm to prevent someone carrying it away when you're not looking. "It can follow and carry things for people around while communicating with their smartphone, and avoiding bumping into other objects," explained Alex Libman, founder of NUA Robotics. "We're combining sensor network, computer vision, and robotics. So if you download our app(应用), press the 'follow me' button, the luggage recognizes its user and knows to follow and communicate."

    NUA is still testing the products and trying to improve features like speed and customization(客户订制), but they hope to make the suitcase available to customers in a year's time. If it proves successful, they want to use the bluetooth pairing technology to automate(自动化操作)lots of other products, like shopping carts at the supermarket. These products are especially meant to be useful to the physically disabled and elderly. "Any object can be smart and robotic," Libman told Mashable. "We want to bring robots into everyday life."

    The Israeli tech company made it clear that the finished product will look just like a common suitcase. They're planning to partner with a carry­on luggage maker, since the product that makes it "smart" weighs just 2.5 pounds and can be fitted on old­fashion luggage.

    With NUA's smart suitcase, carrying around heavy luggage isn't a burden. But how their invention will handle tough blocks like stairs? It will be interesting to wait.

    Moving flight times from night to day could reduce air travel's contributions to global warming, a new study suggests. Scheduling more (lay time flights may reduce the influence of contrails ——the visible lines of white steam that many planes leave behind them in the sky.

    The role of contrails in climate change is still being studied, but some scientists believe they contribute to the greenhouse effect by trapping heat in the atmosphere.

    Nicola Stuber, first author of the study, suggests that contrails' overall impact on climate change is almost as big as that of aircraft^? s carbon dioxide emissions (排放)over a hundred-year period. Aircraft are believed to be responsible for 2-3% of human carbon dioxide emissions. Like other high, thin clouds, contrails reflect sunlight back into space and cool the planet. However, they also trap energy in the atmosphere and increase the warming effect.

    Stuber and other scientists believe that the effect of the contrails is big. "On average, the green-house effect controls the effects of contrails, said Stuber, a meteorologist at England's University of Reading." The warming effect is far greater for contrails left by night flights," Stuber added. "The cooling effect only happens (luring the day when the sun is up. During the night the greenhouse warming is no longer balanced and that is why the contribution of night-flight is so large."

    Most commercial airline traffic occurs during daylight hours. For example, only one in four United Kingdom flights is a night flight, but those flights create some 60% of the warming created by contrails, the study reports.