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).”

    Below is a selection from a popular science book.

    If blood is red, why are veins（静脉） blue?

    Actually, veins are not blue at all. They are more of a clear, yellowish color. Although blood looks red when it's outside the body, when it's sitting in the vein near the surface of the skin, it's more of a dark reddish purple color. At the right depth, these blood-filled veins reflect less red light than the surrounding skin, making them look blue by comparison.

    Which works harder, you heart or your brain?

    That kind of depends on whether you're busy thinking or busy exercising. Your heart works up to three times harder during exercise, and shifts enough blood over a lifetime to fill a supertanker. But in the long run, your brain probably tips it, because even when you're sitting still your brain is using twice as much energy as your heart, and it takes four to five times as much blood to feed it.

    Why do teeth fall out, and why don't they grow back in grown-ups?

    Baby (or “milk”) teeth do not last long; they fall out to make bigger room for bigger, stronger adult teeth later on. Adult teeth fall our when they become damaged, decayed and infected by bacteria. Once this second set of teeth has grown in, you're done. When they're gone, they are gone. This is because nature figures you're set for life, and what controls regrowth of your teeth switches off.

    Do old people shrink as they age?

Yes and no. Many people do get shorter as they age. But, when they do, it isn't because they're shrinking all over. They lose height as their spine（脊柱） becomes shorter and more curved due to disuse and the effect of gravity(重力). Many (but not all) men and women do lose height as they get older. Men lose and average of 3-4 cm in height as they age, while women may lose 5 cm or more. If you live to be 200 years old, would you keep shrinking till you were, like 60 cm tall, like a little boy again? No, because old people don't really shrink! It is not that they are growing backwards —- their legs, arms and backbones getting shorter. When they do get shorter, it's because the spine has shortened a little. Or, more often, become more bent and curved.

    Why does spinning make you dizzy（眩晕的）?

    Because your brain gets confused between what you're seeing and what you're feeling. The brain senses that you're spinning using special gravity-and-motion-sensing organs in your inner ear, which work together with your eyes to keep your vision balance stable. But when you suddenly stop spinning the system goes out of control, and your brain thinks you'removing while you're not.

    Where do feelings and emotions come from?

Mostly from an ancient part of the brain called the limbic system. All mammals have this brain area —- from mice to dogs, cats, and humans. So all mammals feel basic emotions like fear, pain and pleasure. But since human feelings also involve other, newer bits of the brain, we feel more complex emotions than any other animal on this planet.

    If exercise wears you out, how can it be good for you?

    Because our bodies adapt to everything we do to them. And as far as your body is concerned, it's “use it, or lose it”! It's not that exercise makes you healthy, it's more that a lack of exercise leaves your body weak and easily affected by disease

    “Indeed,” George Washington wrote in his diary in 1785, “some kind of fly, or bug, had begun to eat the leaves before I left home.” But the father of America was not the father of bug. When Washington wrote that, Englishmen had been referring to insects as bugs for more than a century, and Americans had already created lightning-bug(萤火虫). But the English were soon to stop using the bugs in their language, leaving it to the Americans to call a bug a bug in the nineteenth and twentieth centuries.

    The American bug could also be a person, referring to someone who was crazy about a particular activity. Although fan became the usual term, sports fans used to be called racing bugs, baseball bugs, and the like.

    Or the bug could be a small machine or object, for example, a bug-shaped car. The bug could also be a burglar alarm, from which comes the expression to bug, that is, “to install (安装) an alarm”. Now it means a small piece of equipment that people use for listening secretly to others' conversation. Since the 1840s, to bug has long meant “to cheat”, and since the 1940s it has been annoying.

    We also know the bug as aflawin a computer program or other design. That meaning dates back to the time of Thomas Edison. In 1878 he explained bugs as “little problems and difficulties” that required months of study and labor to overcome in developing a successful product. In 1889 it was recorded that Edison “had been up the two previous nights discovering ‘a bug' in his invented record player.”

    Billie Holiday was an American jazz singer and songwriter. Nicknamed Lady Day by her loyal friend and musical partner, Lester Young, Holiday had a great influence on jazz and pop singing. Her voiced style, strongly inspired by jazz instrumentalists, pioneered a new way of controlling tempo (节奏). Above all, she was admired for her deeply personal and direct approach to singing.

    She co-wrote a few songs, and several of them have become jazz standards, notably God Bless the Child, Don't Explain, and Lady Sings the Blues. She also became famous for singing jazz standards written by others, including Easy Living and Strange Fruit.

    Her early career is hard to track down with accuracy. But she later gained work singing in local jazz clubs before being spotted by a talent scout (星探), John Hammond in 1933.

    Her voice and recordings were loved for the depth of emotion and intensity she could bring to classic standards. Her range of voice was not the greatest, but her extraordinary low rough voice was soon to become very famous and influential.

    She was an important icon (偶像) of the jazz era and influential in the development of jazz singing. In the late 1930s, she began singing a civil rights song called Strange Fruit, a song which told the tale of a lynching (用私刑处死) of a black man in the Deep South. It was very controversial for that period and it was not played on radios. It was recorded for Commodore Records and she performed it many times over the next 20 years.

    Billie Holiday had a difficult upbringing which influenced her attitude toward life. She experienced many violent relationships. She also became increasingly dependent on various drugs which contributed to her early death in 1959, aged just 44.

    The arts, especially music, should be part of every school's lessons at every grade level. Students would be much smarter if they had some musical experience. They could improve their classroom skills, like paying attention and following directions. People develop all these skills when they learn music. Making music also lets children use their imagination. It provides students with a chance to try out their own ideas.

    Music not only makes children better students, but also gives them something positive to do. In a music program, children can be part of a band instead of joining a gang (团伙). Parents can enjoy listening to their children's music instead of seeing them glued to a computer or TV screen. In a school band, students get to be part of a team. They can get along well with old friends and make new friends through music.

    Music builds self-confidence, too. It gives children a sense of achievement and success. Making music is something for them to be proud of, and it lets kids practice performing in front of an audience. Music gives children an opportunity for self-expression, and that helps develop their self-confidence.

    Once again, music is important because it can make children better students, give them something positive to do, and build their character. That is why music should be offered in every single grade in every school.

    A woman was sitting by herself in a movie theatre. The movie she was about to set was a musical version(版本)of a very successful book that had sold a million copies that year.

    As the woman was waiting for the movie to begin, she noticed that the theatre was very crowded but the two seats next to her were empty.

    Suddenly a large man carrying a big fur coat walked down the aisle(走廊) and sat down, placing the fur coat on the seat next to her.

    When the lights went out, the fur coat bean to move, and the woman realized it was not a coat but a large furry dog. He was sitting up in the seat, watching the movie screen with great interest. As soon as the movie started, the dog began to nod his head and beat his paws (爪) in perfect time to the music.

    When the movie was over, the woman turned to the man and said, “Excuse me, sir, but I've never seen Such a well-behaved dog in a movie theatre before. Does he go to the movies often?”

    “Oh, yes,” replied the man.

    “And he seemed to enjoy everything so much,” she said, “It was just amazing!”

    “As a matter of fact, it surprised me too.” said the man. “He hated the books！”