We produce 500 billion of plastic bags in a year worldwide and they are thrown away polluting oceans, killing wildlife and getting dumped in landfills where they take up to 1,000 years to decompose. Researchers have been unsuccessfully looking for a solution.

    The 16-year-old Canadian high school student, Daniel Burd, from Waterloo Collegiate Institute, has discovered a way to make plastic bags degrade(降解) in as few as 3 months, a finding that won him first prize at the Canada Wide Science Fair, a ＄10,000 prize, a ＄20,000 scholarship, and a chance to revolutionize a major environmental issue.

    Burd's strategy was simple: Since plastic does eventually degrade, it must be eaten by microorganisms(微生物)．If those microorganisms could be identified, we could put them to work eating the plastic much faster than under normal conditions.

    With this goal in mind, he grounded plastic bags into a powder and concocted(调制) a solution of household chemicals, yeast(酵母) and tap water to encourage microbes growth．Then he added the plastic powder and let the microbes work their magic for 3 months．Finally, he tested the resulting bacterial culture on plastic bags, exposing one plastic sample to dead bacteria as a control．Sure enough, the plastic exposed(暴露) to the live bacteria was 17% lighter than the control after six weeks.

    The inputs are cheap, maintaining the required temperature takes little energy because microbes produce heat as they work, and the only outputs are water and tiny levels of carbon dioxide.

    “Almost every week I have to do chores and when I open the closet door, I have piles of plastic bags falling on top of me．One day, I got tired of it and I wanted to know what other people are doing with these plastic bags．The answer: not much．So I decided to do something myself.” Said Daniel Burd.

    I know that there are times when friends are apart for a while – or even forever – and that your lives take different paths. Yet, I always hope for a happy ending. I know that friends reconnect again when it makes sense.

    My friend Julie and I had a long period in our friendship. We used to see each other daily. I would eat brown rice in her kitchen while we shared our secrets.

    Later, we celebrated each other's weddings. My husband and I welcomed Julie's first son (born on my birthday). By the time he was learning to walk, Julie and her family had moved to another city. We spoke on the phone sometimes and exchanged Christmas cards.

    After they welcomed their third son, they moved to Edmonton, which is a farther city. We haven't seen each other since then. They changed their phone numbers. I received a letter from her, but I couldn't find that envelope later. I e-mailed her a few times, but didn't get a reply.

    It was painful not to be in touch with an old friend. I let it go. I knew that Julie and I would reconnect again, when it made sense.

    Last year, Julie's husband got in touch with me on Facebook. I felt something bad, and soon my feeling proved true: Julie had passed away the month before. She died of cancer.

    I regretted that I had not been part of Julie's support system, or the last years of her joyous, painful time on Earth. I cried. I'm so sorry, Julie, for counting on more chances.

    Last week, I donated my hair in memory of Julie to make wigs (假发) for cancer patients. It was a small way of showing that I loved her and will never forget her. And that I look forward to us reconnecting again – when it makes sense.

    Living and dealing with kids can be a difficult job these days, but living and dealing with parents can be even more complex.

    If I have learned anything in my 16 years, it is that communication is very important. With any relationship, you need to let other people know how you are feeling. If you are not able to communicate, you drift apart (疏远). When you are mad at your parents, or anyone else, not talking to them doesn't solve anything.

    Communication begins with the concerns of others. It means that you can't just come home from school, go up to your room and ignore everyone. To keep a good relationship, you must keep communication, even if it's just by writing a note.

    When dealing with parents, you always have to make them feel good about how they are doing as a parent. If you are trying to make them see something as you see it, tell them that you'll listen to what they have to say, but ask them politely to listen to you. Yelling or walking away only makes the situation worse.

    This is an example: one night, Sophie went to a street party with her friends. She knew she had to be home by midnight after the fireworks, but she didn't. She was late getting home. Her parents were mad at first, not giving Sophie a chance to explain why she was late. Later, they kept calm and listened to her. Communication is the key factor here. If Sophie's parents had not been willing to listen, Sophie would have been in a lot of trouble.

    Kung fu is one of a number of Chinese martial arts designed to improve the body and the mind. It is perhaps one of the most widely known martial arts, because many films include its techniques. There are hundreds of styles taught all over the world, although they can be loosely divided into two camps: Shaolin style kung fu, and other techniques, some of which have a history that outdates the Shaolin order.

    Shaolin kung fix has its origins in the fifth century. Like some other martial arts, it began in religious temples, where the monks sought a mind and body discipline (训练方法). In addition to the fighting style, it also includes mental exercises and religious practices designed to balance the whole body.

    Shaolin temples resembled universities, integrating a wide range of subjects of study. Therefore, traditional Shaolin styles such as Wing Chun, Crane, Praying Mantis, and Hung Gar took knowledge from fields outside martial arts, such as the healing arts and meditation. Supporters for Shaolin styles believe that they are more rounded martial arts styles, and that learners will benefit from them on a whole body level.

    Other fighting styles, some of which predate the Shaolin style, are also lumped under the kung fu umbrella. They include Pa-Kua, Eagle Claw, and Eight Drunken Immortals styles. These disciplines are not considered to be Shaolin style because they did not originate in temples and are focused primarily on fighting techniques.

    Whether Shaolin or otherwise, kung fu is characterized by self defense strategies that turn the energy of an attacker against him or her. Although the techniques may vary, most styles teach throws, kicks, punches, and the use of weapons. In addition to the physical discipline, most place a great importance on respect, honor, and living a balanced life.

    Since English biologist Charles Darwin published On the Origin of Species in 1859, scientists have vastly improved their knowledge of natural history. However, a lot of information is still of the speculation, and scientists can still only make educated guesses at certain things.

    One subject that they guess about is why some 400 million years ago, animals in the sea developed limbs (肢) that allowed them to move onto and live on land.

    Recently, an idea that occurred to the US paleontologist (古生物学家) Alfred Romer a century ago became a hot topic once again.

    Romer thought that tidal (潮汐的) pools might have led to fish gaining limbs. Sea animals would have been forced into these pools by strong tides. Then, they would have been made either to adapt to their new environment close to land or die. The fittest among them grew to accomplish the transition (过渡) from sea to land.

    Romer called these earliest four-footed animals “tetrapods”. Science has always thought that this was a credible theory, but only recently has there been strong enough evidence to support it.

    Hannah Byrne is an oceanographer (海洋学家) at Uppsala University in Sweden. She announced at the 2018 Ocean Sciences Meeting in Oregon, US, that by using computer software, her team had managed to link Homer's theory to places where fossil deposits (沉积物) of the earliest tetrapods were found.

    According to the magazine Science, in 2014, Steven Balbus, a scientist at the University of Oxford in the UK, calculated that 400 million years ago, when the move from land to sea was achieved, tides were stronger than they are today. This is because the planet was 10 percent closer to the moon than it is now.

    The creatures stranded in the pools would have been under the pressure of “survival of the fittest”, explained Mattias Green, an ocean scientist at the UK's University of Bangor. As he told Science, “After a few days in these pools, you become food or you run out of food... the fish that had large limbs had an advantage because they could flip (翻转) themselves back in the water.”

    As is often the case, however, there are others who find the theory less convincing. Cambridge University's paleontologist Jennifer Clark, speaking to Nature magazine, seemed unconvinced. “It's only one of many ideas for the origin of land-based tetrapods, any or all of which may have been a part of the answer,” she said.

    If you're looking to fully experience Africa's breathtaking scenery, and have an eye for adventure, then there's only one place to be. Here, inside Africa picks four of the best hikes from across the continent.

    ⒈Kilimanjaro

    Make it to the top of Tanzania's 5,895-meter Kilimanjaro, and you'll be standing at Africa's highest point. The mountain is Africa's most-visited hiking destination, attracting tens of thousands of tourists and adventures every year.

    You don't have to a technical climber to climb Mount Kilimanjaro; you just need not be pretty physically fit. There are six routes to choose from difficulty, scenery and success. No special equipment

    ⒉Atlas mountains

    The High Atlas is an impressive mountainous range in central Morocco that hosts North Africa's highest peak. Mount Toubkal, at 4,165 meters. There's a variety of routes to follow during your climb but inexperienced climbers should note that the hike through the mountain's challenging zones is quite demanding.

    ⒊Mount Kenya

    A long-extinct volcano. Mount Kenya is Africa's second-highest peak, at 5,199 meters.

    Lying just south of the equator, the mountain's deep valleys and diverse wildlife will guarantee you wonderful scenery and a fantastic hiking experience.

    The climb, however, to the mountain's steep ice-capped peaks is quite challenging, making it the most technical, probably, in that East African area.

    ⒋Mount Meru

    Mount Meru may forever exist in the shadow of its neighbor, Kilimanjaro, but Tanzania's second-highest mountain (4,565 meters) has its own devotees.

    It's less known, but Mount Meru is for the true enthusiast who wants to experience what very few people actually do.

    Mount Meru is often used by mountaineers to accustom themselves before trying to conquer Kilimanjaro, or by those wanting a hike with the local Massai.