Security—for the information on your smart phone, as well as for the phone itself—is a hot topic these days.The truth is that you're packing a lot of sensitive information on your phone, and you should keep it safe.

    When it comes to physical security, iPhone users would do well to download Find My iPhone, a free app from Apple that allows you to visit a website and see your (lost, stolen or misplaced) phone on the map.You can then sound an alarm, send a message that will pop up on its screen, lock the phone or erase all your data.

    Android does not have an exact equivalent(等价物), but there are plenty of alternatives. A free app called Lookout offers the find­my­phone feature.The paid version allows you to wipe the data from your phone remotely.

    Then there is your coffee shop's Wi­Fi network.Anyone with minimal technical expert skill can snoop on(窥视) people using shared wireless networks, harvesting passwords and other personal data. Lookout will caution you when you've logged on to an insecure network, but cannot protect you once you're there.

    In order to protect yourself on such networks, you can use a virtual private network, or VPN. This turns all your activity into nonsense to anyone trying to read along with you from across Starbucks. It also keeps websites from tracking you and, if you're travelling, allows you to get access to sites that may be blocked in other countries.

    If you have an iPhone, the simplest VPN app is probably Hotspot Shield, whose distinguishing feature is said to be that it automatically kicks in each time you start browsing (浏览), as opposed to other VPN apps that require you to start them up manually(手动地)．This matters, because even if you decide you want a VPN app, you want to spend approximately zero time thinking about it. For the most part, that was true of Hotspot Shield, though occasionally it took a while to connect or temporarily lost connection without warning. I found myself having to turn the app on and off sometimes, which involved setting my phone constantly.

    If even reading about the settings on your phone drive you crazy, then it is probably best to stay away from a VPN app. But if you're the type who can't resist checking your bank balance from your corner bar, the hassle(麻烦) may be preferable to the risk.

    In the mid-2000s, Waze Mobile co-founder Ehud Shabtai received a cutting-edge (尖端的) gift from girlfriend: a GPS. The expensive gift was supposed to be helpful. But straight out of the box, it was already out of date.

    Shabtai, a coding enthusiast, had an immediate reaction to reinvent. Shabtai's solution? To build an app. With 80 million monthly active users globally and nearly 400,000 superusers who function much like Wikipedia volunteer editors (editing maps rather than words), Waze Mobile caught the eye of Google as a revolutionary approach to navigation (导航).

    Acquired by Google in 2013, Waze's value mainly lies in its high rate of user involvement. Unlike traditional navigation apps that simply show directions, Waze asks its users to report accidents and other road conditions in real time, so other users can avoid the traffic by using an alternative route.

    The goal behind Waze's approach is an ambitious one: not just avoid traffic, but end it altogether. Waze is finding new ways to put its loyal and active user base to use to make that vision a reality, including a plan to make carpooling (拼车) cool.

    To be sure, traffic jams are troubling people all over the world. Waze has been quietly ahead of the game for some time. In 2013, when Waze was just a small digital-mapping business with limited resources it had something Google Maps and other competitors didn't: richer GPS guidance thanks to its stream of live traffic reports from users.

    These users were the basis of Shabtai's plan to solve for his GPS device's “silent” hardware: he grounded the app in software that could be perpetually updated by users, anywhere and anytime.

    Waze Carpool is going straight to the heart of traffic jams, trying to get more drivers off the road and into carpools. The app has already connected tens of thousands of rideseekers with drivers willing to ferry them along a shared route, and that trend could be the answer to a traffic-free future.

    Are you interested in movie musicals? Here are some best movie musicals you need to watch.

    Singin' in the Rain (1952)

    Debbie Reynolds (the heroine) is ultra-charming in this time-honored classic musical about the coming of the talking pictures in movie history. She plays a winning showgirl with a golden singing voice designed for Hollywood stars. You can also see how Gene Kelly (the hero) made a hit in the timeless "Singin'in the Rain".

    The Sound of Music (1965)

    It hit the big screen in 1965 and became an early blockbuster. It's one of those movies that everybody watches again and again. Whether you're singing along to "Do-Re-Mi" or "My Favorite Things", you'll still think of the cute Von Trapp children and the beautiful Austrian setting. Christopher Plummer (the hero) is wonderful as the serious captain melts into gentleness when singing "Edelweiss". And Julie Andrews (the heroine) shows her addictive voice in such songs as "I Have Confidence".

    Chicago (2002)

    Renee Zellweger and Catherine Zeta-Jones sing and dance as criminals in this musical about fame, envy, and murderous love. Famous songs include "Cell Block Tango", where female criminals sing about how they ended up in jail. It won Best Picture, Best Actress in a supporting role, Best Art Direction-Set Decoration, Best Costume Design, Best Film Editing, and Best Sound in Oscar 2003.

    La La Land (2016)

    Struggling actress Mia (Emma Stone) and ambitious jazz pianist Sebastian (Ryan Gosling) begin a romance as they both follow their heart in the path of their dreams in Los Angeles. It won Best Performance by an Actress in a leading role, Best Achievement in Directing, Best Achievement in Cinematography, Best Achievement in Music Written for Motion Pictures, and Best Achievement in Production Design in Oscar 2017.

    Addyson Moffitt is an 8-year-old from Kansas City, Missouri. Maurine Ghelagat is a 9-year-old from a village in Kenya called Bartabwa. It might not seem as if the girls have much in common, but when they met at a dinner two years ago, in Kansas City, they immediately hit it off.

    "We had this one little red ball to play with," Addyson told TIME for Kids. "We didn't have any electronics or phones, no iPads or TV. It was just us playing." Addyson and Maurine still keep in touch now.

    The dinner was hosted by the nonprofit group World Vision International, which builds wells, pipelines, and rain catchers in communities where people find it hard to get clean water. Addyson, was at the dinner because her family supports World Vision. Maurine was there because her village had been without clean water. World Vision fixed that by building a water station there.

    "People helped Maurine so she could have clean water, and kids are dying because they don't have it," Addyson says. "I want to help."

    Races are one way World Vision raises money to pay for its water projects. Runners run a race, often a 26-mile marathon or 13-mile half marathon. They ask people to support them by donating(捐赠) to World Vision.

    Addyson decided to run the 2017 Kansas City Half Marathon for World Vision. At age 7, she was one of the youngest-ever runners in the race, and had to get special permission to take part.

    Addyson spent four months training with her parents, waking up before 6 a.m. to run. Meanwhile, she started fundraising(募捐)by asking friends to make donations as birthday presents and clearing tables at a restaurant for tips.

    By October 2017, when Addyson ran the race, she'd raised more than $20,000. She's the youngest person in World Vision history to raise more than $10,000. In 2018, she ran again and raised $36.000.

    But Addyson's work is not finished. "My goal is for every kid to have clean water," she says.

New research into a long-lived tree has shown some of the tricks that have helped it survive for thousands of years. The ginkgo(银杏树) is a huge, slow-growing tree with fan-shaped leaves, native to China, but planted in parks and gardens across the world. Some of the largest ginkgoes are said to be more than 3, 000 years old.

In order to discover how these and other trees can live for so long, scientists from the US and China studied 34 healthy ginkgoes of different ages. The team studied growth rings in each tree's trunk(树干), as well as cells(细胞) from the bark, leaves and seeds. They found that 600-year-old trees were just as healthy as 2-year-olds.

To learn more, the team then looked in detail at the DNA of nine trees aged between three and 667 years old. DNA is the chemical in the cells of plants and animals that holds instructions that tell any living thing how to grow and develop-including what to do at different times in its life At the beginning of a tree's life, DNA instructs the cells in a seedling to divide quickly so the tree grows rapidly. The cells also make special chemicals to help the young plant survive difficult situations, such as disease. As most trees grow older, their DNA tells their cells to divide more slowly (so growth slows down) and to make fewer chemical defenses(防御).

Ginkgoes, however, do things differently. The team found that although their growth finally slows, both young and old trees make protective chemicals." The secret is keeping a really healthy defense system," said researcher Richard Dixon." As ginkgoes age, they show no sign of weakening their ability to defend themselves from things like disease. "Other trees that live for a long time may have the same ability.

For all their defenses, though, ginkgoes cannot live forever--they finally meet with deadly accidents such as fire, disease and storms. While they last, however, these leafy trees are some of the most beautiful trees in the world.

You've probably heard it a dozen times by now. But here it goes again: Sleep is important. Your mental health and immune (免疫时)system are connected to your sleeping habits. So are your grades, a new study finds. Sleep accounts for nearly one-fourth of the difference among students' grades in a class. So even if you spend hours studying for a test but get too little sleep, you might still do poorly.

Typically, people's sleep schedules are messy and can not be known in advance. Professor Jeffrey Grossman of Massachusetts Institute of Technology in Cambridge wanted to see if sleep links to people's learning performance even when a study was done with people who kept such true-to-life schedules at home. So he turned to Fitbits, which can check how long people sleep and how frequently they wake up. And the researchers looked for 100 students. They focused on these students' sleep patterns in the days and weeks before exams and then compared them to these students' test scores.

"How much time a person sleeps the night. before an exam doesn't affect that person's grade," Grossman says. "A student who sleeps 7 hours every night will do better than a student who sleeps 7.5 hours one night and 6.5 hours another night."

"It's important for people to know that if their Fitbits tell them that they have terrible sleep, that may not actually be so," Michael Scullin, a sleep scientist at Baylor University says. Grossman also raises this point. Fitbit, Inc. makes this advanced tool. But it doesn't share how its tool works. This leaves a question about whether the tool is really correct when checking a student's sleep. Even so, Scullin emphasizes that there are enough data supporting ties between sleep and how well someone performs.

"Students need more sleep and less late evening use of phones and other screens. Even with after-school activities and schoolwork, they need to get enough sleep," Grossman says.