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    Measles(麻疹), which once killed 450 children each year and disabled even more, was nearly wiped out in the United States 14 years ago by the universal use of the MMR vaccine(疫苗). But the disease is making a comeback, caused by a growing anti-vaccine movement and misinformation that is spreading quickly. Already this year, 115 measles cases have been reported in the USA, compared with 189 for all of last year.

    The numbers might sound small, but they are the leading edge of a dangerous trend. When vaccination rates are very high, as they still are in the nation as a whole, everyone is protected. This is called “herd immunity”, which protects the people who get hurt easily, including those who can't be vaccinated for medical reasons, babies too young to get vaccinated and people on whom the vaccine doesn't work.

    But herd immunity works only when nearly the whole herd joins in. When some refuse vaccination and seek a free ride, immunity breaks down and everyone is in even bigger danger.

    That's exactly what is happening in small neighborhoods around the country from Orange County, California, where 22 measles cases were reported this month, to Brooklyn, N.Y., where a 17-year-old caused an outbreak last year.

    The resistance to vaccine has continued for decades, and it is driven by a real but very small risk. Those who refuse to take that risk selfishly make others suffer.

    Making things worse are state laws that make it too easy to opt out(决定不参加) of what are supposed to be required vaccines for all children entering kindergarten. Seventeen states allow parents to get an exemption（豁免), sometimes just by signing a paper saying they personally object to a vaccine.

    Now, several states are moving to tighten laws by adding new regulations for opting out. But no one does enough to limit exemptions.

    Parents ought to be able to opt out only for limited medical or religious reasons. But personal opinions? Not good enough. Everyone enjoys the life-saving benefits vaccines provide, but they'll exist only as long as everyone shares in the risks.

    Did you know that the position(位置) you choose to sleep in says something about what kind of person you are?

    A study of 1,000 British people has been done by Chris Idzikowski, a British professor and director of the Sleep Assessment and Advisory Service in the UK. It looked at the six most common sleeping positions and which personalities tend to match them. Have a look:

    ⒈Fetus (胎儿) position – This is the most common sleeping position. About 41 percent of the participants said they sleep in this position. These sleepers may appear to be strong but they are usually sensitive (敏感的) and shy. The more they curl (蜷缩) up, the more worried they are.

    ⒉Log position (树干睡姿) – This is the second most common position. People who sleep like a log are usually stubborn.

    ⒊Yearner position (向往型睡姿) – This position says that you are open-minded and eager (急切的) to face challenges.

    ⒋Soldier position – These sleepers lie on their backs with their arms down and close to the body. They are usually reserved and quiet.

    ⒌Freefall position – People who sleep in this position are outgoing (外向的) but feel a lack of control in their lives. This is the least comfortable position.

    ⒍Starfish position – People who sleep like this are good listeners, helpful, and uncomfortable being the center of attention.

    The iPhone XS and iPhone XS Max's internals are nearly the same: With each, you get a 12 megapixel camera, better-sounding speakers and the ability to pack two SIM cards into one device for international travelers or people who have to turn between a device for work and one for personal use.

    The phones come with Apple's new A12 bionic chip, which helps make Face ID and games load faster. Apple played up the speed of these new phones during its product announcement, and they are fast. But so were the models before them.

    Both models feature beautiful OLED screens that make watching videos, especially on the XS Max, totally surprising.

    Battery life is also improved on both devices. Apple (AAPL) says you can spare about 30 minutes longer on the XS compared to last year's X, and 90 minutes longer on the Max. It's not a game changer, but we'll take any extra minutes we can get.

    There is one major difference between the iPhone XS and XS Max: size. The Max is unquestionably big, but it's technically the same size as the iPhone 8 Plus. The edge-to-edge screen creates the illusion（幻想）the device itself is 21% larger than its predecessor, but it'll fit in your hands just as easily (or not) as older Plus models.

    But it's hard to shake the feeling that the device is big just to be big. Unlike the Samsung (SSNLF) Galaxy Note or the iPad, the XS Max doesn't support many features tailored for bigger screens, such as another row of apps or a side-by-side display that lets you use two apps at once. It's a missed opportunity.

    The real star of the new models is the camera. A new feature called Smart HDR shoots a four-frame object taken at different exposures and settings and mixes them together to create more detailed shots — similar to an existing feature on the Google Pixel 2.

    But the likely fan favorite feature is a change to the iPhone's Portrait Mode that lets you change the depth of a photo after you take it, allowing you to have more creative control. For example, you can snap a shot of a friend on a beach and change the background for an artsy feel. If you decide later you want to see more of the ocean, you can change the background via the edit button.

    It's an impressive feature, but the results also depend on your photo skills and the lighting. When it's good, it's really good. When it's not, you'll still get a good-looking picture. The Pixel 2 and Samsung Galaxy S9 offer a similar feature, too.

    The XS and XS Max come with headphones, but unlike last year, you won't find an adapter included in the box. This means you'll need to spend $9 more if you want to use an old pair of headphones. It's Apple's way of saying it's finally time to get over the fact there's no longer a headphone jack.

    The morning of March 2, 2012, was a busy one for the students in Mrs. Goodknight's class in Henryville, Indiana. There was morning meeting with poems to read, jokes to share, and tests to prepare for. "It was just an ordinary day," says student Lyric Darling, 12.

    At noon, while students played basketball under a sunny sky, a huge tornado (龙卷风) was forming 50 miles away. Around 2:25 p.m. 20 minutes before school was supposed to let out, a huge tornado touched down in Fredericksburg, 20 miles away. As word spread, parents rushed to the school. Teachers rushed to get kids onto buses or into waiting cars. By 2:45, the skies were darkening.

    "I was crying," says Lyric. "All around me, kids were crying." Two buses returned to the school with students whose parents had not been home. Teachers brought the kids to the office, where they all took cover under desks. Suddenly the power went out. And then the tornado attacked the school, filled with wood and trees and glass. The tornado was over the school for less than one minute. In that time, it almost completely destroyed the school. Teachers were about to lead the group out of the office when a second tornado was upon them. When it finally ended, the group made its way out of the building.

    Over the next few hours, parents arrived, overjoyed to find their children. The next day, it was clear: All of Henryville's people were safe.

    There were so many sad and frightening stories. Some students saw the tornado with their own eyes. Some lost their homes. But many described how the community (社区) came together to help and support each other. "You learn what's important," Mrs. Goodknight says.

    The Environmental Film Festival has become one of the world's grandest supporters of the environmental film. To offer fresh views on global environmental issues, this year's festival will include a record of 190 films from 50 countries. including 110 premieres(首映). Here are just a few of the highlights.

⒈Hot Water

    Featured among the festival's opening night films is the highly expected "Hot Water, " a look 2 the depressing destructive effects of uranium铀) mining in the American West. Former US. Rep Denis Kucinich. who ran for president in 2004 and 2008, is featured in the film, along with filmmakers Elizabeth Kucinich and Lizabeth Rogers Directed by Kevin Flint and

⒉To the Wonder

    To the Wonder is the latest film by will-known American Director Trrence Malick. The film, "an exploration of love set against the power of nature," stars Ben Aleck, Olga Kurylenko. Rachel McAdams and Javier Bardem The film premiered in competition at the 2012 Venice Film Festival and is making is Washington D.C premiere during the festival.

⒊Revolution

    This Washington D.C. premiere presents the Canadian filmmaker and environmental activist, Rob Stewart's new work, "Revolution" an urging cry to today's youth to change the planet before it's too late. The award-winning documentary takes Stewart through 15 countries over four years, in an effort to find the secret to save the ecosystems we rely on for survival.

⒋The Fifth Season

    Beautiful and mystery, Jessica Woodworth's latest feature, "The Fifth Season", is a poetic meditation (EA) on nature in battle against humans." The dramatic narrative takes place in Belgium's secret Ardennes, where the locals rely on the land, but nature takes a turn and seems to go on mysterious strike, In French and Flemish with English subtitles. Directed and produced by Woodworth and Peter Brosens.

Biofuels (生物燃料), gained from plants and animal matter, are a key solution to the environmental problems caused by fuels like coal. "Bioalcohol (生物酒精) is the most common biofuel and is produced by sugars found in materials such as corn. With some engine redesigned, it can be used directly by cars, buses, etc. ," says Professor Daniel Tan, "12 percent of transport fuel could come from biofuels, especially bioalcohol, by 2030. "

But a 2016 study of biofuels said, "Bioalcohol presently is mostly produced with food crops. Altogether, the environmentally-friendly biofuels rely on about 2-3 percent of the global water and land used for agriculture, which could feed a large number of hungry people. "

Energy experts have therefore been trying to deal with the problem. Recent research led by an international team found that the agave (龙舌兰) plant might offer a way out. This plant tends to be the right bioalcohol source to supersede others such as sugarcane (甘蔗) and corn.

Daniel Tan explains that the agave can be grown in unfavorable conditions and is not a major food crop. "It can grow in areas that lack water and rainfall without being watered by farmers, and it does not compete with food crops or put demands on limited water. This kind of useful plant is recently being grown in Australia. It can survive Australia's hot summers," he says.

The study finds that sugarcane produces just a little more fuel per square meter each year than the agave. However, the agave outperforms sugarcane in a range of areas, including pollution to the earth, and water using. The agave uses 69 percent less water than sugarcane and 46 percent less water than corn for the same amount of fuel produced. As for corn，it produces less fuel per square meter each year than the agave.

However, Daniel Tan states: "The first generation of bioalcohol from the agave recently faces a big competition from oil, whose recent low price makes it far more attractive to customers. Without some policy support from the government, bioalcohol production from the agave faces big challenges. "