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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.

    Dogs are wonderful companions all their own, but they can also help change your life so that you're more accepting of new friendships. A new study studied how dogs' brains responded to the human voice and found that “the human brain responds to dog emotions the same way it responds to human emotions” and that the dog's brain does the same.

    Dogs are pack animals, so in terms of pet ownership, your dog will prefer to stay with you rather than somewhere alone. Think about how this concept applies to friendship. People today are getting more and more used to spending time on social networking, email, and text. While all methods of communication are good, there is nothing like seeing your friends and hearing their voice. With good friends, sometimes a look explains everything, and you can only get this when you're together hanging out in person.

    Let's face it, dogs never hide their feeling. They let you know what they enjoy doing most, whether it is chasing a ball, going for a walk, or getting a treat. For people, it's harder to be open with your emotions. But in order to truly find a friend, you'll need to let go of your fears and put trust into your friends. The reality is that you'll never make everyone you meet happy one-hundred percent of the time, so if your friends and family think you're great, put aside the need to be liked by everyone.

    Dogs wait for you to come home and are so happy to see you again that they practically do a happy dance when you walk through the door. Friends, on the other hand, are sometimes so busy that even hearing from a friend becomes an unwelcome interruption. Rather than avoid calls or emails, make a point to talk to friends on a regular basis.

    Kung fu is one of a number of Chinese martial arts designed to improve the body and the mind. It is perhaps one of the most widely known martial arts, because many films include its techniques. There are hundreds of styles taught all over the world, although they can be loosely divided into two camps: Shaolin style kung fu, and other techniques, some of which have a history that outdates the Shaolin order.

    Shaolin kung fix has its origins in the fifth century. Like some other martial arts, it began in religious temples, where the monks sought a mind and body discipline (训练方法). In addition to the fighting style, it also includes mental exercises and religious practices designed to balance the whole body.

    Shaolin temples resembled universities, integrating a wide range of subjects of study. Therefore, traditional Shaolin styles such as Wing Chun, Crane, Praying Mantis, and Hung Gar took knowledge from fields outside martial arts, such as the healing arts and meditation. Supporters for Shaolin styles believe that they are more rounded martial arts styles, and that learners will benefit from them on a whole body level.

    Other fighting styles, some of which predate the Shaolin style, are also lumped under the kung fu umbrella. They include Pa-Kua, Eagle Claw, and Eight Drunken Immortals styles. These disciplines are not considered to be Shaolin style because they did not originate in temples and are focused primarily on fighting techniques.

    Whether Shaolin or otherwise, kung fu is characterized by self defense strategies that turn the energy of an attacker against him or her. Although the techniques may vary, most styles teach throws, kicks, punches, and the use of weapons. In addition to the physical discipline, most place a great importance on respect, honor, and living a balanced life.

    In one of the world's most forbidding environments, Polar bears spend !heir summers roaming (漫步) the Arctic on large pieces of floating ice. They drift(漂移) for hundreds of miles, finding mates, hunting for seals , and fatting themselves up for the winter. Without the floating ice , the world's largest bears could not survive Yet at this moment , the polar bears' Arctic habitat (栖息地) is melting away under it because of global warming.

    Over the past three decades, more than a million square miles of floating ice has disappeared Scientists predict that, if the current rate of global warming continues, most, if not all, of the bears' floating ice will be gone by 2100. As a result, the world's polar bears could face global dying out by the end of this century.

    Already, the ice on the southern edge of the polar bears' habitat is melting about three weeks earlier than in the past. The loss of those key weeks leaves the bears less time to hunt, eat and store up fat. Once the ice melts, the bears must fast for up to eight months on land until the floating ice returns. As a result of early melting, there has been a 14 percent decline in the Hudson Bay polar bear population over the past ten years- a fall clearly caused by global warming.

    Besides, a growing number of polar bears may be drowning (溺水) as they are forced to swim more often, and for longer distances, looking for ice sheets(冰原). According to a report by the US Mincrals Management Service, researchers observed four dead polar bears floating 60miles off Alaska in September of2006 and said it was likely that many other bears swimming far off shore also drowned. Scientists have concluded that the worldwide population of about 20,000polar bears is likely to become smaller by more than 30 percent in the next 35 to 50 years alone.

    Children moving from primary to secondary school are ill-equipped to deal with the impact of social media, as it is playing an increasingly important role in their lives and exposing them to significant emotional risk, according to a recent report by the Office of the Children's Commissioner for England.

    The report shows that many children in year 7 -- the first year of secondary school, when almost all students will have a phone and be active on social media -- feel under pressure to be constantly connected.

    They worry about their online image, particularly when they start to follow celebrities on Instagram and other platforms. They are also concerned about “sharenting” -- when parents post pictures of them on social media without their permission – and worry that their parents won't listen if they ask them to take pictures down.

    The report, which was created with data from focus group interviews with 8 to 12-year-olds, says that although most social media sites have an official age limit of 13, an estimated 75 percent of 10 to 12-year-olds have a social media account.

    Some children are almost addicted to “likes”, the report says. Aaron, an 11-year-old in year 7, told researchers, “If I got 150 likes, I'd be like, that's pretty cool, it means they like you.” Some children described feeling inferior(差的) to those they follow on social media. Aimee, also 11, said, “You might compare yourself because you're not very pretty compared to them.”

    Children's Commissioner for England Anne Longfield is calling on parents and teachers to do more to prepare children for the emotional impact of social media as they get older. She wants to see the introduction of compulsory digital literacy and online resilience (适应力) lessons for students in year 6 and 7.

    “It is also clear that social media companies are still not doing enough to stop under-13s using their platforms in the first place,” Longfield said.

    “Just because a child has learned the safety messages at primary school does not mean they are prepared for all the challenges that social media will present,” Longfield said.

    “It means a bigger role for schools in making sure children are prepared for the emotional demands of social media. And it means social media companies need to take more responsibility,” Longfield said.

Four Best Places to Travel for the Summer of 2019

    If you're still deciding where to take your summer vacation, 2019 brings major anniversaries, new flight routes, buzzy museum openings and more. In no particular order, check out our picks for where to travel this summer:

    Salar de Uyuni, Bolivia

    The Salar de Uyuni, or Uyuni Salt Flat, is a vast expanse near the Bolivian Andes that resembles ice. The surreal landscape is actually leftover salt from ancient lakes. A large lounge dome offers a public space with tables, floor cushions and hanging lanterns. Food is provided by Gustu in La Paz, considered one of Latin America's top restaurants. Beyond simply enjoying the food and scenery, guests can hike to the crater of Tunupa Volcano, mountain bike across the Salar or visit the village of Jirira. Come nightfall, on­site telescopes take full advantage of the star­flooded sky.

    Las Vegas

    There's the Park Theater, where up to 5,200 people can enjoy A­list artist residencies: Lady Gaga is currently in residence until November, with Janet Jackson and Cher starting this summer. For good measure, Bruno Mars will also be performing some dates in September. Daniel Humm and Will Guidara, perhaps best known for NYC's Eleven Madison Park restaurant, are behind the NoMad Restaurant and NoMad Bar. And foodies will no doubt want to experience Roy Choi's Best Friend, the first brick­and­mortar restaurant following his hugely successful Korean BBQ truck.

    Nova Scotia

    Nova Scotia often gets overlooked for popular provinces like British Columbia and Quebec, but its quiet charms are worth exploring. Cape Breton Island takes a bit of work to reach, but it's here that you'll find challenging hiking trails, a scenic driving route minus the traffic and real­deal Celtic culture. The Halifax Jazz Festival, held in the province's capital, is considered Nova Scotia's largest music festival, and goes down from July 9­14 on the waterfront.

    Grand Canyon

    It's the Grand Canyon's 100th anniversary as a national park, and there are multiple ways to celebrate this notable occasion. From June 22­29, stargazers can join amateur astronomers for free at the park's North and South Rims for the Star Party. Telescopes will be on hand to find planets (Jupiter and Saturn among them), star clusters and nebulae. There will also be slide show programs with a different focus each night, from protecting dark skies to learning how planets form. Constellation talks and night sky photography workshops are among the free offerings, just allow yourself enough time since you won't be the only one with this idea.