If feels like every time my mother and I start to have a conversation, it turns into an argument. We talk about something as simple as dinner plans and suddenly, my mother will push the conversation into World War? She'll talk about my lack of a bright future because I don't plan to be a doctor. And much to her disappointment, I don't want to do any job related to science, either. In fact, when I was pushed to say that I planned to major (主修) in English and communications, she nearly had a heart attack.

"Why can't you be like my coworker's son?" she bemoans all the time. Her coworker's son received a four year scholarship and is now earning 70,000 dollars a year as an engineer. I don't know what to answer except that I simply can't be like Mr Perfect as I've called the unnamed coworker's son. I can't be like him. I'm the type of person who loves to help out in the community, write until the sun goes down, and most of all, wants to achieve a career because I love it, not because of fame (名声) or salary.

    I understand why my mother is worried about my future major. I've seen my mother struggle to raise me on her small salary and work long hours. She leaves the house around 6:30 am and usually comes home around 5 pm or even 6 pm. However, I want her to know that by becoming a doctor, it doesn't mean I'll be successful. I'd rather follow my dreams and create my own future.

    The Boy Made It!  One Sunday, Nicholas,a teenager, went skiing at Sugarloaf Mountain in Maine．In the early afternoon, when he was planning to go home, a fierce snowstorm swept into the area．Unable to see far,he accidentally turned off the path．Before he knew it,Nicholas was lost,all alone!He didn't have food,water,a phone,or other supplies．He was getting colder by the minute．

    Nicholas had no idea where he was．He tried not to panic．He thought about all of the survival shows he had watched on TV．It was time to put the tips he had learned to use．

    He decided to stop skiing．There was a better chance of someone finding him if he stayed put．The first thing he did was to find shelter from the freezing wind and snow．If he didn't,his body temperature would get very low,which could quickly kill him．

    Using his skis,Nicholas built a snow cave．He gathered a huge mass of snow and dug out a hole in the middle．Then he piled branches on top of himself,like a blanket,to stay as warm as he could．

    By that evening,Nicholas was really hungry．He ate snow and drank water from a nearby stream so that his body wouldn't lose too much water．Not knowing how much longer he could last,Nicholas did the only thing he could—he huddled(蜷缩)in his cave and slept．

    The next day,Nicholas went out to look for help,but he couldn't find anyone．He followed his tracks and returned to the snow cave,because without shelter,he could die that night．On Tuesday,Nicholas went out again to find help．He had walked for about a mile when a volunteer searcher found him．After two days stuck in the snow,Nicholas was saved．

Nicholas might not have survived this snowstorm had it not been for TV．He had often watched Grylls' survival show —-Man vs．Wild． That's where he learned the tips that saved his life．In each episode(一期节目) of Man vs．Wild, Grylls is abandoned in a wild area and has to find his way out．

    When Grylls heard about Nicholas' amazing deeds,he was super impressed that Nicholas had made it since he knew better than anyone how hard Nicholas had to work to stay alive．

    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.

    Professional athletes pay a high price for their pursuit of excellence and glory. Training to the limit tears muscles and wears out joints. Gymnasts often need hip replacements when barely into middle age. Few footballers make it to the end of their careers with their knees intact.

    But many also run a darker risk: doping—the use of banned athletic performance-enhancing drugs by athletic competitors. The Winter Olympics in Pyeongchang, in South Korea, starts this week in its shadow. Years after whistle-blowers first revealed wholesale (大规模的) doping in Russia, the International Olympic Committee (IOC) at last decided to bar it from taking part. But it has allowed many Russians to compete as individuals. And on the eve of the competition the Court of Arbitration for Sport (CAS) said that 28 others should receive a more tolerant penalty from the IOC, further muffling the anti-doping message.

    Russia's doping is unusual only in its scale and institutional nature. No country or sport is immune. Studies, and an anonymous survey at the World Athletics Championships in 2011, suggest that a third of athletes preparing for big international competitions take banned substances. Yet just 1-2% fail a test each year. Lance Armstrong, a cyclist who won the Tour de France seven times and later admitted to doping all the while, was tested on 250 occasions. The few times he failed, he avoided punishments by claiming he had taken anti-inflammatories (消炎药) for saddle-sores (骑行引起的肌肉酸痛).

    Doping is more sophisticated than when some states used steroids (类固醇) to bulk up athletes. New drugs are designed to be undetectable in a blood or urine sample. Many athletes "blood dope," receiving transfusions or taking a drug that stimulates the production of red blood cells to improve their physical strength. Soviet athletes who were fed steroids suffered a host of serious problems in later life. They were more likely to commit suicide, or to miscarry (流产) or have a disabled child. No one knows what risks those taking new "designer" versions are running. Blood-doping can cause heart attacks; more than a dozen cyclists' deaths have already been linked to it.

    The agencies that set out to stop doping are hugely outclassed. As the argument over punishments on Russia illustrate, they are divided and weak. Most testing is done by national bodies, which may not try very hard to find evidence that would get their own stars banned. The World Anti-Doping Agency (WADA), which oversees them, is packed with officials from national sports federations and the IOC. Their interests are likewise conflicted. Its budget is tiny. The system seems to be designed to look tough but punish only the occasional scapegoat (替罪羊). Honest athletes deserve better.

    Almost every second of every day an older adult falls in the United States. That's approximately 29 million falls per year and nearly 27, 000 deaths, according to the Centers for Disease Control and Prevention.

    Still in the stating stage, the Active Pelvis Orthosis (APO) system in Switzerland wants to make a lightweight, wearable exoskeleton (外骨骼) that could detect signs of balance loss and assist with balance recovery to keep the elderly wearer from falling, only when needed.

    Other exoskeletons, either in development or on the market today, assist with movement and make heavy objects feel lighter. Mobility-impaired people can walk again. But none of these devices predict what the wearer is going to do next and take measures to correct an unsteady move.

    The 3 kilogram (6.7 pound) exoskeleton was built entirely from scratch by the research team and is designed to be worn on the lower half of the body. A waistband connects to two movable carbon fiber braces (支架), each one positioned on the outer side of a leg. Tiny motors and so-called "adaptive oscillators" (适配振荡器) in the computer circuits use a special process to detect the, wearer's unique paces. That part takes just a few minutes.

    While wearing the exoskeleton, a person may feel the braces and the motors pushing slightly on their legs. If their paces go against normal, the motors create a force in the braces that cause them to stiffen up and push a little more strongly against the legs, which provides stability.

    In the next three years, the APO hopes to develop something that is commercially available.

Biologists from the John Innes Centre in England discovered that plants have a biological process which divides their amount of stored energy by the length of the night. This solves the problem of how to portion out (分配) energy reserves during the night so that the plant can keep growing, yet not risk burning off all its stored energy.

While the sun shines, plants perform photosynthesis (光合作用). In this process, the plants change sunlight, water and carbon dioxide into stored energy in the form of long chains of sugar, called starch (淀粉). At night, the plants burn this stored starch to fuel continued growth.

"The calculations are precise so that plants prevent starvation but also make the most efficient use of their food," said study co-author Alison Smith. "If the starch store is used too fast, plants will starve and stop growing during the night. If the store is used too slowly, some of it will be wasted. "

The scientists studied the plant Arabidopsis, which is regarded as a model plant for experiments. To give the plants some math tests, the biologists let night arrive unexpectedly early or late for them.

During one of the exams, they shut off the lights early on them that had been grown with twelve-hour days and nights. Putting them into darkness after only an eight-hour day means they didn't have time to store as much starch as usual. And this forced the plants to adjust their normal nightly rhythm.

Amazingly, even after this day length trick, the plants did very well in their exams and ended up with just five percent of starch left over at the end of the night. They had neither starved, nor stored starch that could have been used to fuel more growth.

The authors suggested that similar biological calculators may explain how a migratory bird, the little stint, can make a five-thousand-kilometer journey to their summer habitat in the Arctic and arrive with enough fat reserves to survive only approximately half a day more, on average.

The results of the study were published in e Life.