Some years ago, writing in my diary used to be a usual activity.I would return from school and spend the expected half hour recording the day'sevents, feelings, and impressions in my little blue diary. I did not reallyneed to express my emotions by way of words, but I gained a certainsatisfaction from seeing my experiences forever recorded on paper. After all,isn't accumulating memories a way of preserving the past?

When I was thirteen years old, I went on a long journey on footin a great valley, well equipped with pens, a diary, and a camera. During thetrip, I was busy recording every incident, name and place I came across. I feltproud to be spending my time productively, dutifully preserving for futuregenerations a detailed description of my travels. On my last night there, Iwandered out of my tent, diary in hand. The sky was clear and lit by the glareof the moon, and the walls of the valley looked threatening behind their screenof shadows. I automatically took out my pen...

At that point, I understood that nothing I wrote could evermatch or replace the few seconds I allowed myself to experience the dramaticbeauty of the valley. All I remembered of the previous few days were the dullcharacterizations I had set down in my diary.

Now, I only write in my diary when I need to write down aspecial thought or feeling. I still love to record ideas and quotations thatstrike me in books, or observations that are particularly meaningful. I takepictures, but not very often only of objects I find really beautiful. I'm nolonger blindly satisfied with having something to remember when I grow old. Irealize that life will simply pass me by if I stay behind the camera, busypreserving the present so as to live it in the future.

I don't want to wake up one day and have nothing but a pile ofpictures and notes. Maybe I won't have as many exact representations of peopleand places; maybe I'll forget certain facts, but at least the experiences willalways remain inside me. I don't live to make memories--I just live, and thememories form themselves.

Not so long ago, most people didn't know who Shelly Ann FrancisPryce was going to become. She was just an average high school athlete. There was every indication that she was just another American teenager without much of a future. However, one person wants to change this. Stephen Francis observed then eighteen-year-old Shelly Ann as a track meet and was convinced that he had seen the beginnings of true greatness. Her time were not exactly impressive, but even so, he sensed there was something trying to get out, something the other coaches had overlooked when they had assessed her and found her lacking. He decided to offer Shelly Ann a place in his very strict training sessions. Their cooperation quickly produced results, and a few years later at Jamaica's Olympic trails in early 2008, Shelly-Ann, who at that time only ranked number 70 in the world, beat Jamaica's unchallenged queen of the sprint(短跑).

“Where did she come from?” asked an astonished sprinting world, before concluding that she must be one of those one-hit wonders that spring up from time to time, only to disappear again without signs. But Shelly-Ann was to prove that she was anything but a one-hit wonder. At the Beijing Olympics she swept away any doubts about her ability to perform consistently by becoming the first Jamaican woman ever to win the 100 meters Olympic gold. She did it again one year on at the World Championship in Berlin, becoming world champion with a time of 10.73— the fourth fastest time ever.

Shelly-Ann is a little woman with a big smile. She has a mental toughness that did not come about by chance. Her journey to becoming the fastest woman on earth has been anything but smooth and effortless. She grew up in one of Jamaica's toughest inner-city communities known as Waterhouse, where she lived in a one-room apartment, sleeping four in a bed with her motherand two brothers. Waterhouse, one of the poorest communities in Jamaica, is a really violent and overpopulated place. Several of Shelly-Ann's friends and family were caught up in the killings; one of her cousins was shot dead only a few streets away from where she lived. Sometimes her family didn't have enough to eat. She ran at the school championships barefooted because she couldn't afford shoes. Her mother Maxime, one of a family of fourteen, had been an athlete herself as a young girl but, like so many other girls in Waterhouse, had to stop after she had her first baby. Maxime's early entry into the adult world with its responsibilities gave her the determination to ensure that her kids wouldnot end up in Waterhouse's roundabout of poverty. One of the first things Maxime used to do with Shelly-Ann was taking her to the track, and she was ready to sacrifice everything.

        It didn't take long for Shelly-Ann to realize that sports could be her way out of Waterhouse. On a summer evening in Beijing in2008, all those long, hard hours of work and commitment finally bore fruit. The barefoot kid who just a few years previously had been living in poverty, surrounded by criminals and violence, had written a new chapter in the history of sports.

        But Shelly-Ann's victory was far greater than that. The night she won Olympic gold in Beijing, the routine murders in Waterhouse and the drug wars in the neighbouring streets stopped. The dark cloud above one of the world's toughest criminal neighbourhoods simply disappeared for a few days.“I have so much fire burning for my country,” Shellysaid. She plans to start a foundation for homeless children and wants to build acommunity centre in Waterhouse. She hopes to inspire the Jamaicans to lay down their weapons. She intends to fight to make it a woman's as well as a man's world.

        As Muhammad Ali puts it, “Champions aren't made in gyms. Champions are made from something they have deep inside them. A desire, a dream, a vision.” One of the things Shelly-Ann can be proud of is her understanding of this truth.

    You may think that light pollution isn't something extraordinarily important. You may believe that every other type of pollution has a larger impact on the environment that light pollution does. But light pollution is serious.

    Light pollution, or “sky glow”, is the glow you can see at night above cities and towns. Light pollution is a problem that has been accompanying man ever since he started his first fire some 15,000 years ago. Light pollution is the light that comes from streetlights, buildings, parking lots and any other source of light that is reflected or directed into the atmosphere.

    Urban light pollution means that one-fifth of the world's population can no longer see the Milky Way(银河) with the naked eye(肉眼). Many city kids, even if they did look through the orange smog above their heads, would probably see only a handful of stars. We have lost our view of the stars, and we have mucked up our  night-time environment as well. Astronomers are calling for the dark places on Earth to be preserved as national parks.

    Lots of people find the ever-brightening night annoying, and animals that are programmed to prefer the dark may avoid a brightened habitat. Sea turtles can get lost searching for a beach to lay eggs, and their hatchlings(孵化的幼仔)may confuse over-lit beachfront resorts(度假胜地) for the ocean horizon, wasting precious energy needed to find the sea and escape predators(食肉动物). Because their necks aren't yet long enough to see things far away, baby turtles rely on the mirror image of the moon to guide them to the sea, to begin their new life. A car may even hit a particular turtle, which was thinking the light from a nearby city was moonlight reflecting off the ocean waves. Birds that live in and around cities can die because of sky glow, too. The bright lights can blind them, leading to countless collisions with buildings and other tall structures.

    On an individual level, people can help reduce much sky glow by using lighting only when necessary. The stars above us are priceless heritage— for not only for astronomers but for all humans. More of our children should be able to look up at night and see the Milk Way.

    Part-time jobs for 15 and 16 years olds

    Waiter / Waitress

    A job as a waiter or waitress is a good choice for 16-year-olds. Not only can one earn $9-$12 an hour, but they can also get the tips (小费). Most people that visit a restaurant don't just have good food. They come here to relax and have a good time. Besides serving food quickly, a young waiter who talks to them politely with a smile on his face will make the diners enjoy their time at the restaurant.

    Work in a library

    If one is fond of books, working in a library is another suitable choice. Besides the pay is good, it offers a lot of free time when students can actually sit down and finish their homework. So on returning home, they would have time to hang around with friends or just relax. So working in a library is an excellent part-time job for teens, especially for school students.

    Internet jobs

    There are many ways of making money through online jobs like clicking on advertisements, visiting sites and signing up with them. However, such online jobs don't pay well. A better Internet job for teens is to complete online surveys. These are quite simple surveys that usually ask one about his/ her opinions and ideas. Many companies use these ideas to make products designed for teenagers.

    You probably know that frogs hop (双足跳). But did you know that there's a small frog in the Pacific Northwest that belly flops (肚子先着水)? It's called a tailed frog.

    Dr. Rick Eisner, who has been studying tailed frogs for the past few years, says, "I've looked at thousands of jumps and have never seen them land on their feet like other frogs." Most of the time, tailed frogs land on their stomachs and then bring their back legs in to prepare for another jump.

    Eisner first noticed these frogs because of the way they swim. Other frogs kick both of their back legs at the same time. But when a tailed frog swims, it pushes first with one leg and then the other.

    To try to find out why tailed frogs bellyflop, Eisner and other scientists collected and filmed different kinds of frogs. They found that all of the frogs start their jumps the same way: They hold out their legs. The change comes in the landing. Tailed frogs can't move their back legs as quickly as other frogs do. Maybe they don't need to. Tailed frogs live around water and quickly jump into the water to escape danger.

    Early frogs developed around watery areas and could jump quickly into the water to escape danger. Scientists think those frogs blended in with (与…融合在一起) the green plants on the side of the rocky rivers, just like today's tailed frogs. "I would guess that other animals would have problems detecting them," explains Eisner. When other animals find those early frogs, the frogs could jump into the river. They didn't need to continue hopping.

    Tailed frogs and other kinds of frogs went their own ways about 200 million years ago. Tailed frogs stayed by rivers. Other kinds of frogs moved to places where new hopping skills allowed them to survive.

    Microsoft announced this week that its facial-recognition system is now more accurate in identifying people of color, touting (吹嘘)its progress at tackling one of the technology's biggest biases (偏见).

    But critics, citing Microsoft's work with Immigration and Customs Enforcement, quickly seized on how that improved technology might be used. The agency contracts with Microsoft for cloud-computing tools that the tech giant says is largely limited to office work but can also include face recognition.

    Columbia University professor Alondra Nelson tweeted, "We must stop confusing 'inclusion' in more 'diverse' surveillance (监管)systems with justice and equality."

    Facial-recognition systems more often misidentify people of color because of a long-running data problem: The massive sets of facial images they train on skew heavily toward white men. A Massachusetts Institute of Technology study this year of the face-recognition systems designed by Microsoft, IBM and the China-based Face++ found that facial-recognition systems consistently giving the wrong gender for famous women of color including Oprah Winfrey, Serena Williams, Michelle Obama and Shirley Chisholm, the first black female member of Congress.

    The companies have responded in recent months by pouring many more photos into the mix, hoping to train the systems to better tell the differences among more than just white faces. IBM said Wednesday it used 1 million facial images, taken from the photo-sharing site Flickr, to build the "world's largest facial data-set" which it will release publicly for other companies to use.

    IBM and Microsoft say that allowed its systems to recognize gender and skin tone with much more precision. Microsoft said its improved system reduced the error rates for darker-skinned men and women by "up to 20 times," and reduced error rates for all women by nine times.

    Those improvements were heralded(宣布)by some for taking aim at the prejudices in a rapidly spreading technology, including potentially reducing the kinds of false positives that could lead police officers misidentify a criminal suspect.

    But others suggested that the technology's increasing accuracy could also make it more marketable. The system should be accurate, "but that's just the beginning, not the end, of their ethical obligation," said David Robinson, managing director of the think tank Upturn.

    At the center of that debate is Microsoft, whose multimillion-dollar contracts with ICE came under fire amid the agency's separation of migrant parents and children at the Mexican border.

    In an open letter to Microsoft chief executive Satya Nadella urging the company to cancel that contract, Microsoft workers pointed to a company blog post in January that said Azure Government would help ICE "accelerate recognition and identification." "We believe that Microsoft must take an ethical stand, and put children and families above profits," the letter said.

    A Microsoft spokesman, pointing to a statement last week from Nadella, said the company's "current cloud engagement" with ICE supports relatively anodyne(温和的)office work such as "mail, calendar, massaging and document management workloads." The company said in a statement that its facial-recognition improvements are "part of our going work to address the industry-wide and societal issues on bias."

    Criticism of face recognition will probably expand as the technology finds its way into more arenas, including airports, stores and schools. The Orlando police department said this week that it would not renew its use of Amazon. com's Rekognition system.

    Companies "have to acknowledge their moral involvement in the downstream use of their technology,"

    Robinson said. "The impulse is that they're going to put a product out there and wash their hands of the consequences. That's unacceptable."