Vitamin B could help reduce the effects of the dangerous type of air pollution, according to a new study published on Monday. In the first study of its kind, a team of international researchers looked into the damage caused by one of the pollutants that have the severest impact on health—PM2.5.

    They found that Vitamin B supplement could effectively reduce the impact of the tiny particles     （颗粒）on the human body, although they stressed that the research was in its early stages. According to the WHO, 92% of the world's people are living in places where the PM2.5 level goes beyond the recommended level. So it's urgent to find a solution to the problem.

    According to this study, published in the PNAS, 10 volunteers were initially exposed to clean air and given a placebo (安慰剂）to check their baseline responses. The group then kept on taking placebos tor tour weeks before being exposed to heavily polluted air from downtown Toronto, where an estimated 1,000 cars passed every hour. The bad air was delivered to the volunteers through an "oxygen type" face mask. The experiment was then repeated, with each volunteer taking a Vitamin B supplement daily, made up of 2.5mg of folic acid, 50mg of Vitamin B6, and l mg of Vitamin B12.

    Vitamin B6 can be found in liver, chicken, nuts and other things, and Vitamin B12 in fish, meat, eggs, milk and some cereals. The researchers found that four weeks of Vitamin B supplements — the damage of PM2.5 effects by 28-76%. The results emphasized how prevention at an individual level could be used to fight against the damage of PM2.5, the researchers said.

    Last year I lived in Chile for half a year as an exchange student with the American Field Service. Compared to most visitors, I didn't travel much. I lived with a Chilean family and had the responsibilities of any Chilean teenager. I went to school every day, in uniform. I had good days and bad days and days that I didn't understand.

    Chuquicamata, my host community, is a mining camp in the Atacama Desert. There is no disco, no shopping center, no museum or beach. Driveways must be watered daily to keep the dust down.

    When I arrived here, I was scared. It was so different from the urban middle-class America I was accustomed to. There were lost dogs on the streets, and a constant cloud of brick-colored dust came from the mine. There was no downtown, few smoothly paved(用砖石铺的) streets, and little to do for amusement. The people worked extremely hard. Rain was a rare phenomenon; earthquakes and windstorms were frequent.

    I had studied Spanish for two and a half years and was always one of the best students in my class. But in my first week in Chile I was only able to communicate and needed one person to whom I could explain my shock. I couldn't speak the thoughts in my head—and there were so many.

    Most exchange students experience this like me. Culture shock presents itself in everything from increased aggression towards the people to lack of appetite. I was required to overcome all difficulties. Being an exchange student is not easy.

    As time passed, everything changed. I began to forget words in English and to dream in Spanish and love Chilean food. I got used to not depending on expensive things for fun. Fun in Chuquicamata was being with people. And I took math, physics, chemistry, biology, Spanish, art, and philosophy.

    But the sacrifices were nothing compared to the gain. I learned how to accept as well as to succeed in another culture. I now know the world is my community and have a much deeper understanding of both myself and others.

    Sydney has a huge bus system(系统). No buses accept cash, and a ticket needs to be bought ahead of time. The buses often run at busy hours and regularly(有规律地) during the day. The Sydney Explorer bus provides air-conditioned service and stops at 27 tourist attractions. Its partner, the Bondi Explorer, stops at 19 attractions. Tickets allow holders to jump on and off as they please, and they are valid(有效的) for one or two days. It's an easy way to see the city and the surroundings.

    Sydney's train service runs throughout the central city area and the surroundings. Tickets can be bought from machines that operate 24 hours a day or from ticket offices. The monorail(单轨铁路) travels through central Sydney. It is the most excellent way to gain a good view of the whole city. The monorail runs every three to five minutes, and it takes 15 minutes to complete its journey.

    Sydney is built around a harbor, and the Parramatta River has a large ferry（渡轮）system. It serves the area around the harbor. These include Taronga Zoo, Darling Harbor, Rose Bay, the North Shore, Cockatoo Island and Sydney Olympic Park. The ferries have operated for more than 135 years and 14 million passengers take the ferries each year.

    Water taxis can transport passengers to specific locations(地点), and offer guided tours of waterways. They also offer special services that some visitors may enjoy. The tickets sell for 20 AUD (Australian dollars)for a day or 57 AUD for a week. It is strange, isn't it?

    Students in many countries are learning English. Some of these students are little children. Others are teenagers. Many are adults. Some learn at school, others learn by themselves. A few learn English over the radio, on TV, or in films. One must work hard to learn another language.

    Why do all these people want to learn English? It's difficult to answer this question. Many boys and girls learn English at school because it is one of their subjects for study. They study their own language, math, English, and so on. Some people learn it because it is useful for their work. Many people learn English for their work and higher studies, because at colleges or universities some of their books are in English. Other people learn English because they want to read newspapers or magazines in English.

    It is quite reasonable to blame traffic jams, the cost of gas and the great speed of modern life, but manners on the road are becoming horrible. Everybody knows that the nicest men would become fierce tigers behind the wheel. It is all right to have a tiger in a cage, but to have one in the driver's seat is another matter altogether.

    Road politeness is not only good manners, but good sense too. It takes the most cool-headed drivers great patience to give up the desire to beat back when forced to face rude driving. On the other hand, a little politeness goes a long way towards reducing the possibility of quarrelling and fighting. A friendly nod or a wave of thanks in answer to an act of politeness helps to create an atmosphere of good will and calm so necessary in modern traffic condition. But such behaviors of politeness are by no means enough. Many drivers nowadays don't even seem able to recognize politeness when they see it.

    However, misplaced politeness can also be dangerous. Typical examples are the driver who waves a child crossing the street at a wrong place into the path of oncoming cars that may be not able to stop in time. The same goes for encouraging old ladies to cross the road wherever and whenever they want to. It always amazes me that the highways are not covered with the dead bodies of these grannies (奶奶).

    An experienced driver, whose manners are faultless, told me it would help if drivers learnt to correctly join in traffic stream without causing total blockages that give rise to unpleasant feelings. Unfortunately, modern drivers can't even learn to drive. Years ago, experts warned us that the fast increase of the car ownership would demand more give-and-take from all road users. It is high time for all of us to take this message to heart.

    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."