The expression “a thirst for knowledge" may soon have a new meaning for millions of people who have no way to get clean water. Researchers have developed a book with specially treated pages that can turn dirty water into clean and drinkable water. They say their invention could improve the lives of many in the developing world.

    About 700 million people around the world are at risk of disease or even death because their drinking water is not clean. The water is polluted by harmful bacteria.

    The book contains 25 pages. Each page is about one millimeter thick. The pages contain very small particles (微粒) of silver. The pages can be used as filters（过滤器）to remove harmful microorganisms (微生物) that can pollute drinking water. The filter kills the organisms that pass throughit.

    Pictures on the pages show the dangers of dirty water and how to use the book for those unable to read. The pages aremade of filter paper. They are designed to be torn from the book. Water can bepoured through the paper to be cleaned.

    Ms. Dankovich, the inventor, says eachpage can treat up to 100 liters of water. She recently presented her invention at the meeting of the American Chemical Society in Boston, Massachusetts. She was asked whether she had considered adding classic literature on the book's pages.

    "The idea of classic texts—that's of interest maybe later. We have discussed a little bit more exciting text. But we really haven't had the time to go through that part," she says.

    Teri Dankovich and another researcher tested the drinkable book in Bangladesh, Ghana and South Africa. The tests proved to be successful.

    Water for Life, a non-government alorganization, has provided financial support for the project.

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    Say you're in the supermarket parking lot，holding your baby，bags of goods，and trying to open your car. A stranger walks up and says，" Here，let me hold your baby." Should you let him?

    According to a new New York University study，knowing whether or not to trust someone is so important that we can tell whether a face is trustworthy before we even consciously know it's there. The researchers knew from previous studies that people are fairly similar when it comes to how they judge a face's trustworthiness. They wanted to find out whether that would be true if people only saw a face for a quick moment—an amount of time so short that it would prevent making a conscious judgment.

    To carry out their study，the researchers monitored the amygdala (扁桃腺结构) of 37 volunteers while showing them 300 faces for 33 milliseconds each. Those faces had already been tested with a different set of 10 subjects，who saw them for much longer. In those earlier tests，people agreed about whether to trust each face. In this new study，fascinatingly，different parts of the amygdala lit up when a subject saw an untrustworthy face and a trustworthy one—and it lit up more when the face in question was suspicious (可疑的).

    " Faces that appear likely to cause harm are suddenly tracked by the amygdala，so it could then quickly change other brain processes and make fast responses to people—approach or avoid，" says Jon Freeman，the study's senior author. "Our talents for making instant judgments could either come from birth or be learned from the social environment."

    So should you trust the guy in the parking lot? Your brain already knows.

    He was a founder of modem Chinese literature. He was regarded as "an old man always telling the truth". Living across two centuries, he experienced many periods of danger and suffering but never lost his beliefs. His name was Ba Jin.

    As the 101-year-old legendary（传奇的）writer passed away in Shanghai after a six-year battle with disease, millions of Chinese were deeply sad. People in Shanghai and Chengdu gathered around his old house and literature museum to mourn for the great man.

    "My school held a series of ceremonies to express our deep sorrow,'' said Zuo Shang, a 17-year-old girl in Shanghai, who appreciates much of Ba's works. "He is a great writer who wrote so many masterpieces, but what I admire about him the most is his courage to tell the truth, 'Telling the truth, being an honest man.' That's what I learned from him," explained Zuo.

    Ba Jin was born in 1904 in Chengdu, Sichuan Province. A son of a wealthy family, Ba helped the poor ever since he was a child. It is they who taught him a strong yet down-to earth way of living.

    Ba finished his first novel, "Destruction", in 1929 during his travels to France. His later masterpieces, "Family" "Spring" and "Autumn", mirrored the struggles, tragedies and loves of the young in a feudal society. The books encouraged Chinese people not to give in to fate and to be their own masters.

    "Ba Jin told the true story of his country and his people. His great love and service to them meant he was thinking about what he could do for them," said Bing Xin, a well-known writer and also his good friend.

    Like other famous writers in China, Ba suffered in the "cultural revolution" during 1966—1976. But several years later, Ba examined his hard experience in strict introspection（自我反省）instead of hatred. His book, "Random Thoughts"， in 1979 displayed his real thoughts with painful sincerity and won him his reputation for honesty.

    "It really hurts to recall my past mistakes, but 1 have to," said the respectable man. "Always tell the truth. Say what you think in the bottom of your heart. That's my life motto."

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Any schoolchild knows that a whale breathes through its blowhole. Fewer know that a blowhole is a nostril （鼻孔） slightly changed by evolution into a form more useful for a mammal that spends its life at sea. And only a dedicated expert would know that while toothed whales, such as sperm whales, have one hole, baleen （鲸须） whales, such as humpback and Rice whales, have two. 

Even among the baleen whales, the placing of those nostrils differs. In some species they are close together. In others, they are much further apart. In a paper published in Biology Letters Conor Ryan, a marine biologist at the Scottish Association for Marine Science, suggests why that might be. Having two nostrils, he argues, helps whales smell in stereo （立体空间）. 

Many types of baleen whales eat tiny animals known as zooplankton （浮游动物）， which they catch by filtering （过滤） them from seawater using the sheets of fibrous baleen that have replaced teeth in their mouths. But to eat something you first have to find it. Toothed whales do not hunt by scent. In fact, the olfactory bulb-the part of the brain that processes smell-is absent in such creatures. But baleen whales still have olfactory bulbs, which suggests smell remains important. And scent can indeed give zooplankton away. Zooplankton like to eat other tiny creatures called phytoplankton （浮游植物）. When these are under attack, they release a special gas called dimethyl sulphide, which in turn attracts baleen whales. 

Most animals have stereoscopic senses. Having two eyes, for instance, allows an animal to compare the images from each in order to perceive depth. Having two ears lets them locate the direction from which a sound is coming. Dr Ryan theorized that paired blowholes might bring baleen whales the same sorts of benefits. 

The farther apart the sensory organs are, the more information can be extracted by the animal that bears them. The researchers used drones to photograph the nostrils of 143 whales belonging to 14 different species. Sure enough, baleen whales that often eat zooplankton, such as the North Atlantic right whale, have nostrils that are farther apart than do those, such as humpback whales, that eat zooplankton occasionally. Besides allowing them to breathe, it seems that some whales use their blowholes to determine in which direction dinner lies.