While Jennifer was at home taking an online exam for her business law class, a monitor（监控器）a few hundred miles away was watching her every move.

    Using a web camera equipped in Jennifer's Los Angeles apartment, the monitor in Phoenix tracked how frequently her eyes moved from the computer screen and listened for the secret sounds of a possible helper in the room. Her Internet access was locked — remotely — to prevent Internet searches, and her typing style was analyzed to make sure she was who she said she was: Did she enter her student number at the same speed as she had in the past? Or was she slowing down?

    In the battle against cheating, this is the cutting edge and a key to encouraging honesty in the booming field of online education. The technology gives trust to the entire system, to the institution and to online education in general. Only with solid measures against cheating, experts say, can Internet universities show that their exams and diplomas are valid — that students haven't just searched the Internet to get the right answers.

    Although online classes have existed for more than a decade, the concern over cheating has become sharper in the last year with the growth of “open online courses”. Private colleges, public universities and corporations are jumping into the online education field, spending millions of dollars to attract potential students, while also taking steps to help guarantee honesty at a distance.

    Aside from the web cameras, a number of other high-tech methods are becoming increasingly popular. Among them are programs that check students' identities using personal information, such as the telephone number they once used.

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    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.

How did the ancient Chinese keep food warm in winter?

    Facilities like electric rice cookers, microwaves, and electric kettles, make it easy for people to keep food warm and enjoy a comfortable winter. So how did Chinese people in ancient times keep food warm in winter without these? In fact, ancient Chinese people used their own methods of heat preservation as early as the Shang and Zhou dynasties.

● “Wen Ding”, ancient rice cooker

    One of the major functions of an electric rice cooker is to keep food warm. The “Wen Ding”, an ancient cooking container, served the same purpose, but instead of using electric energy, the ancient cooking container, served the same purpose, but instead of using electric energy, the ancient cooking container preserved heart by burning fuels like charcoal.

    The “Wen Ding” unearthed in Nanjing in 1989 is thought to be the oldest of its kind discovered in China, dating back to the Stone Age, The craftsmanship of making the “Wen Ding” was developed in the Bronze Age. The bronze Ding from Shang and Zhou dynasties took on different shapes and structures.

● “Ran LU”, ancient small hot pot

    The “Ran LU” is a small size cooking vessel(器皿) made of bronze, which can be divided into three parts. A charcoal stove forms the main structure, with a bottom tray to hold charcoal ashes, and a movable cup at the top. Some experts have concluded that the vessel's structure suggests it may have been used as a small hot pot and that these vessels became popular in the Warring States Period(475—221 BC)

●Bronze You, ancient kettle

    The Bronze You was one of the most common wine containers during the Shang and Zhou dynasties. The Bronze You can also be used to warm wine. For example, the Bronze You with beast mask design, unearthed in Jiangxi province, has an opening where charcoals could be placed. Just as people today can't do without an electric kettle, the Bronze You allowed people to enjoy a hot drink.

●Bronze Yan, ancient steamer

    Although the “Wen Ding” was effective at keeping food warm, the ancient Chinese people later found that its burning produced pollution. As a result, the Bronze Yan was made with a two-tier structure and used to steam rice and other grains. After the Eastern Han Dynasty (AD 25-AD 220), further improvements to the Bronze Yan led to the modern-day steamer.

    What's more exciting than having a fresh hot pizza delivered to your door?  How about having it brought to you by a robot?  Thanks to Domino's Robotic Unit or DRU, that just became a reality! On March 8, the three-foot tall robot delivered its first pizza to some lucky residents in Brisbane, Australia.

    The fully autonomous DRU is the result of cooperation between Domino's Pizza Australia and Marathon Robotics. The 450-pound machine that travels at a maximum speed of 12. 4 miles an hour can traverse a distance of up to 12 miles and back, before requiring to recharge the battery. LIDAR, a laser-based sensor technology similar to the one used in self-driving cars, enables DRU to detect and avoid obstacles, while traditional sensors, much like those used in vacuum robots ensure its path is safe as it heads to its destination.

    The robot can fit up to ten pizzas and even has a separate cold area to accommodate drink orders. To access their food, customers have to enter the unique code provided for them by the company. This not only ensures that they pick up the right pizza, but also prevents the pies from getting stolen.

    Scientists expect additional DRU's to be ready for service in their various Queensland locations within the next six months. But don't expect these super cute robots to replace humans anytime soon. According to Domino's the DRU still needs extensive testing, which the company believes could take up to two years.

    And then there is also the issue of regulations. The public use of autonomous vehicles is still banned in most countries. But Don Meij, the CEO and Managing Director of Domino's Pizza Australia New Zealand Ltd, is not worried. He is“confident that one day DRU will become an integral part of the Domino's family. ”

    Weighing too much can damage your health, and obesity is a growing problem for both kids and adults around the world. Sleep might be one answer to the problem. A new study has found that elementary school students who slept too little were more likely to gain pounds.

    Past studies have shown a link between sleeping less and weighing more, but scientists have had a tough time determining "which came first, the chicken or the egg," says Julie C. Lumeng of the university of Michigan in Ann Arbor. In other words, it hasn't been clear whether kids who weigh too much have trouble sleeping, or whether sleeping less leads to weight gain. Both scenarios (可能出现的情况) seemed equally possible.

    To get a better idea of which causes which, Lumeng and her colleagues interviewed the parents of 785 third graders from around the United States. The parents answered questions about how well their kids slept that year. Three years later, the parents answered the same questions. By sixth grade, 18percent of kids involved in the study were obese.

    The scientists found no relationship between weight and the students' race or gender. It also didn't matter how strict their parents were, or whether they were boys or girls. Obesity struck all of these groups equally. Instead, sleep seemed to be the key factor. Over the three years of study, the children averaged a healthy 9. 5 hours of sleep a night. Some kids, however, slept a lot more or less than others.

    For the sixth graders, every hour of sleep above the 9. 5houraverage was linked to a 20 percent lower risk of being obese. Sleep appeared doubly important for the third graders. Every extra hour of sleep they got was linked to a 40 percent drop in obesity.

    When I was a kid, I was the girl who kept the training wheels on my bike as long as possible. Even my younger sister had got rid of them much earlier than me. But as I began to grow older, this changed.

    All this happened on the Bike Safety Day. It is supposed to be a fun day at school when all of us kids bring our bikes to school and the school provides us with the opportunity to ride outside and learn proper bike safety. Sounds like fun, right? No. In fact, it caused me to panic. What was I going to say when my friends asked me about my training wheels?

    With the pressure of everyone seeing my training wheels, I determined to let them go. This was the first big change I'd ever made on my own.

    I went to my parents and told them all about my dilemma. They were more than happy to help. We went outside and got my bike. Instead of running away and hiding behind, I stood in front of my bike and took great pride in my decision as my dad removed the training wheels.

    I got on and steadied myself. My heart raced but my feet and hands were calm. My dad started to push before my feet even moved and suddenly I was off. The fear faded away and a relaxed mind came into its place. It was crazy to think how quickly I learned something that took so long for me to even try!

    My confidence soared. This was going to be the start of a brand new world for me. My accomplishment would carry me forth to new goals and wins. I realized that if I set my mind to something, I could achieve it.