New mercury(汞) threat to oceans from climate change

    Rising temperatures could boost mercury levels in fish by up to seven times the current rates, said Swedish researchers in an article published in Science Journal. They've discovered warming increases levels of the toxin (毒素) in sea creatures. In experiments, they found that extra rainfall drives up the amount of organic material flowing into the seas. This alters the food chain, adding another layer of complex organisms which boosts the concentrations of mercury up the line.

    Mercury is one of the world's most toxic metals, and according to the World Health Organization, is one of the top ten threats to public health. The substance at high levels has been linked to damage to the nervous system, paralysis and mental impairment in children.

    The most common form of exposure to mercury is by eating fish containing methylmercury(甲基水银), an organic form of the chemical which forms when bacteria react with mercury in water, soil or plants. Levels of mercury in the world's ecosystems have increased by between 200% and 500%, since the industrial revolution say experts, driven up by the use of fossil fuels such as coal.

    In recent years there have been concentrated efforts to limit the amount of mercury entering the environment, with an international treaty, called the Minamata Convention, signed by 136 countries in place since 2013.

Researchers hope that the Minamata treaty will be successful and countries reduce the amount of mercury that is being produced. Otherwise this discovery of a previously unknown source could have impacts for human health.

    Other researchers in the field say that the new study highlights important issues that have previously been little known.

     “This work experimentally proves that climate change will have a significant effect of methylmercury budgets in coastal waters and its accumulation in fish,” said Milena Horvat from the Jozef Stefan Institute in Slovenia.

     “This work will also help us understand the formation of mercury in fish and help reduce mercury from emission sources (primarily industrial).”

    A good teacher is many things to many people. In my own experience, the people I respect the most and think about the most are the teachers who demanded the most discipline (纪律) from their students.

    I miss one teacher in particular that I had in high school. I think she was a good teacher because she was a very strict person. I remember very clearly a sign on her classroom door. It was a simple sign that said,    "Laboratory: in this room the first five letters of the word was stressed not the last seven." In other words, labor for her was more important than oratory, which means making speeches.

    She prepared her work very carefully and told us to do the same. We got lots of homework from her. Once she had broken her arm, and everybody in the class thought that maybe the homework load would be reduced, but it continued just the same. She checked our work by stamping her name at the bottom of the papers to show that she had read them.

    I think sometimes teachers who demand the most are liked the least. But as time goes by, this discipline really seems to benefit the students.

    Taxi-booking app Uber agreed to sell its business in China to Didi Chuxing. The two firms had been fierce competitors, but Didi Chuxing had controlled the Chinese market with an 87% share.

    Uber China launched in 2014, but it had failed to make any profit for a long time. Cheng Wei, founder and chief executive of Didi Chuxing, said the two companies had learned a great deal from each other over the past two years in China. He added that the deal would set the mobile transportation industry on a healthier path of growth at a higher level. As part of the deal, Mr. Cheng would join the board of Uber, while Uber chief executive Travis Kalanick would also join Didi's board.

    Uber's China business would own its separate branding while US-based Uber Technologies would hold about 17.5% in the combined company. Didi Chuxing is backed by Chinese Internet giants Tencent and Alibaba.

    Uber had been struggling to break into the Chinese market despite having Chinese search engine Baidu as an investor. Last February, the company admitted it was losing more than $1 billion a year in China. “Funding their Chinese dreams was becoming too expensive for Uber,” Duncan Clark, chairman of Beijing-based consultancy BDA, told the BBC. Travis Kalanick said, “As a businessman, I've learned that being successful is about listening to your head as well as following your heart.”

    The fierce competition had led both companies to spend much more on their journeys. The combination is likely to see fewer such subsidies（补贴）. “One thing to watch carefully is how quickly consumers feel the impact as subsidies are withdrawn.” Mr. Clark added.

    The deal with Didi Chuxing came just days after China had agreed to provide a legal framework for taxi-ordering apps. Both Uber and Didi welcomed the decision. The new rules took effect last November and could, among other things, forbid such platforms to operate below cost.

    The human body is designed to move. But modern lifestyles and office jobs rarely give us the chance to move around. As we know, we're sitting while we're eating; we sit in the car and we sit while we watch TV. And many of us sit for many hours at work.

    New research shows that sitting less than three hours a day might extend your life by two years. Peter Katzmarzyk, a scientist at the University of Louisiana in the southern United States, says that sitting is ubiquitous in our lives, meaning it is something we do all the time, everywhere.

    However, Mr. Katzmarzyk says that does not mean you can sit for the rest of your waking hours. He also says you may exercise often, "We can't throw away physical activity. It's extremely important. We have 60 years of research showing us that."

    Mr. Katzmarzyk and his colleagues are part of a new generation of researchers studying how sitting all day affects length of life. "Studies that have assessed the relationship between sitting and mortality (死亡率) or television viewing and mortality are very rare. There's only been a few of them, actually five or six now, in the last four or five years." They found that cutting television time to less than two hours a day could add one point four years to life.

    Luckily, change is already coming to some offices, especially in the design of desks. A "standing desk" lets people stand while they work. Another new design is called the "treadmill desk." A treadmill is an exercise machine that lets you walk in one place. Even some U.S. schools are beginning to experiment with desks that are part bicycle to keep children moving. That's one of the strategies that many companies are using now.

    Mr. Katzmarzyk also says studying this problem has inspired his team to make a few changes in their own lives.

    It was the last time Susan Butcher ran the Iditarod Trail Sled Dog Race in 1992. An hour into the race, Susan and her sled dog team sped down a hill and crashed into a fallen tree. Although hurt, Susan continued the difficult race.

    The Iditarod Race started in 1925 when a doctor in Nome, Alaska was desperately in need of medicine to stop the spread of a deadly disease. Only a hospital had what he needed, but it was 700 mile-away! In January, it was too dangerous to send a boat and too stormy for his tiny airplane. The only hope was to use several sled dog teams following a trail, called the Iditarod Trail. They passed the medicine from one sled team to another. Wind and snow did not stop the men and their dogs. The medicine was delivered in record time. The race follows the route of the famous medicine run. Over 1,000 miles long, it is considered the toughest race in the world.

    Susan Butcher was born in Cambridge, Massachusetts. In her teens Susan was given a Siberian husky dog and became very interested in huskies as sled dogs. After reading about the Iditarod Race, Susan moved to Alaska. She got several jobs to earn money to buy herself a sled and a team of huskies. After years of hard work and training, Susan achieved her dream of racing on the Iditarod Trail.

    In 1978, at the age of 24, Susan entered the race for the first time and became the first woman to finish in the top 20. In 1982 she came in second. In 1984 she was leading her team across a frozen waterway when they fell into the water. Her lead dog managed to pull Susan and the other dogs out of danger. Remarkably, she came in second.

    In her fourth race, in 1985,a starving moose(驼鹿) attacked her dogs, killing two and injuring eleven. Susan had to leave the race. In 1986 Susan joined the race again. This time, she won. She won again in 1987. In 1988 she became the first person ever to win three Iditarod races in a row. Unbelievably, Susan won for the fourth time in 1990.

    For many people, the Transformers movies are the greatest Hollywood blockbusters (大片). And among the Transformers themselves, the yellow Autobot named Bumblebee is certainly the favorite. He may be one of the smallest and weakest of the alien machines, but he is always loyal to his friends and shows great bravery in battle.

    In the new film, Bumblebee is found in a junkyard (废车场) and is full of honeybees. He always finds himself in awkward (尴尬的) situations, but people like his cute and naive looks. In addition to his blue eyes, Bumblebee's body language and movements are adorable. At one point, he sits with his legs straight out, with his huge feet making him look like a 5-year old trying on his dad's shoes.

    Bumblcbee is the Transformer who has the greatest affinity (亲和力) with humans. He starts journey with Watson, who is at a loss about her future and wants a friend. As a result of their adventure together. Watson grows up and starts to work toward her life goal of becoming a musician. As for Bumblebee, as we know, is a robot from outer space, he now has a better understanding of his task to protect the Earth. Every adventure has a beginning, as the movie poster puts it. More importantly, every adventure needs a good partner. The considerate, positive and warm Bumblebee is definitely a good choice according to US actress I Hailee Stcinfeld, who plays Watson in the film.