No one is sure how the ancient Egyptians built the pyramids near Cairo. But a new study suggests they used a little rock‘n'roll. Long-ago builders could have attached wooden pole s to the stones and rolled then across the sand, the scientists say.
“Technically, I think what they're proposing is possible,” physicist Daniel Bonn said.
People have long puzzled over how the Egyptians moved such huge rocks. And there's no obvious answer. On average, each of the two million big stones weighed about as much as a large pickup truck. The Egyptians somehow moved the stone blocks to the pyramid site from about one kilometer away.
The most popular view is that Egyptian workers slid the blocks along smooth paths. Many scientists suspect workers first would have put the blocks on sleds(滑板). Then they would have dragged them along paths. To make the work easier, workers may have lubricated the paths either with wet clay or with the fat from cattle. Bonn has now tested this idea by building small sleds and dragging heavy objects over sand.
Evidence from the sand supports this idea. Researchers found small amounts of fat, as well as a large amount of stone and the remains of paths.

However, physicist Joseph West thinks there might have been a simpler way , who led the new study . West said , “I was inspired while watching a television program showing how sleds might have helped with pyramid construction . I thought , ‘Why don't they just try rolling the things?'“A square could be turned into a rough sort of wheel by attaching wooden poles to its sides , he realized . That , he notes , should make a block of stone” a lot easier to roll than a square”.
So he tried it.
He and his students tied some poles to each of four sides of a 30-kilogram stone block. That action turned the block into somewhat a wheel. Then they placed the block on the ground.
They wrapped one end of a rope around the block and pulled. The researchers found they could easily roll the block along different kinds of paths. They calculated that rolling the block required about as much force as moving it along a slippery(滑的)path.
West hasn't tested his idea on larger blocks, but he thinks rolling has clear advantages over sliding. At least, workers wouldn't have needed to carry cattle fat or water to smooth the paths.

    It puzzled Emily when she was aware of something wrong. She tripped upon men's clothing "hidden" around her house.

    The 38-year-old woman says, at the beginning, she was confused to see quite a few photographs in her phone that she did not remember taking. She was the subject but something was different. Her friends started falling away and she did not know why. Her long-term relationship with her boyfriend also ended suddenly.

    Now she knows those men's clothing belonged to one of her "alternatives" and the same person was responsible for her closest friends' leaving her.

    In an interview, Emily said she was not allowed to name "the man" who takes over her body. She was not allowed to name any of her six alternative persons. She said, "I am aware that they are not real people, not physical people. They exist in an imaginative world. However, all those alternatives should be treated with dignity and respect."

    Emily has what's called Dissociative Identity Disorder（DID分离性身份识别障碍）, a condition characterized by the presence of two or more split personalities that have power over a person's behaviour.

    Her condition resulted from a car accident five years ago. It was August, 2012, when her vehicle broke down on the side of the road. A speeding driver crashed into her car. She wasn't physically injured but she suffered a mental condition caused by severe brain injury. Shortly after that, she discovered she wasn't alone inside her head. Switching between personalities happens frequently but there is no real pattern. It can be weeks between incidents then, for whatever reason, it happens more regularly.

    One of her alternatives is a smoker, even though she is not. Upon waking, she says there are messages in her head that she is a smoker. She describes her lifestyle as "isolated".

    "People consider DID as tragedy" she says, "I just want to make an effort to tell others that we deserve respect, that we are legally accepted members of society, and we hope to live a normal life. I'm not stupid, I'm not spiting or running around people with knives. I have a mental problem but try to live a normal life. I completed a course at Harvard, I wrote a book, I'm able to communicate well. I mother my two kids well. I'm not on welfare."

    Actually, she volunteers for an organization helping children. She also spends time speaking out about her condition and has written a book on the subject, hoping to help others who are experiencing the same trouble.

    Years ago parents worried their children would learn the truth about Santa Claus(圣诞老人)from others, but now they have a new problem—the Internet.

    A recent study from Hide My Ass! Shows 1 in 8 American parents said the Internet told their children the truth about Santa Claus. 44% of parents thought Google was a danger to this Christmas story, as children searched for Santa and found pages explaining he is not real. About 34 percent of children questioned Santa Claus after seeing ads online for gifts they had asked for in their letters to the North Pole (北极). Sadly，one in three children said their Christmas spirit was dead after reading a post saying Santa wasn't real.

    Before the Internet, the only way children found out their parents bought their gifts was if they were in a bad hiding place. Today, two-thirds of parents never clear their browser (浏览器) history, making it easy for kids to find out the gifts under the tree weren't put there by a happy man and his little helpers.

    To keep Mr. Claus alive, “Keep Believing in Santa”, an organization created by Hide My Ass!, helps kids believe in Santa. Parents receive free software from the organization that monitors all online search results and web pages that could tell kids the truth about the man who lives in the North Pole, by hiding any information that may suggest he doesn't exist.

    However, there is still a higher possibility of the Internet now being the main cause of a child's belief in Santa ending, and it can also result in kids finding out sooner than for those born before the digital age.

    ''With this organization, we wanted to give parents a new tool that would allow them to keep the magic of Christmas and the mystery of Santa for that little bit longer,” Cian  Mckenna-Charley, marketing director at Hide My Ass!.

    Nowadays, most people have a device that features artificial intelligence (AI), with the likes of Siri always there to greet us with a friendly voice.

    But Microsoft's XiaoIce is different. Launched in 2014 for the Chinese market, "she" has a creative advantage over her competitors. While most AI assistants simply read out information they get online, XiaoIce has a "realness" that the others are short of. Indeed, if you asked nicely, she could read you a poem from the weekly column in China Daily.

    The newspaper has been printing XiaoIce's self-penned poetry each week since Aug 19, taken from her own book of poems, The Sunlight that Lost the Glass Window.

    To turn XiaoIce into a master of poetry, Microsoft scientists "fed" her the works of over 500 influential modern poets, reported China Daily.

    This led to her figuring out a writing style of her own and creating over 70,000 original poems. Most of the poems are so comparable to those written by humans that they cannot be easily distinguished, and XiaoIce's book even got good feedback from experts.

    "XiaoIce's work carries a strange taste. The more you chew on it, the more interesting it becomes," Scholar Zhang, a literature professor at the Nanjing University of Science and Technology, told China Daily.

    However, it seems not everyone is a fan. "The poems dissatisfied me with their slippery tone and rhythm. The sentences were aimless, lacking the inner logic for emotional expression," Yunnan-based poet Yu told China Youth Daily. This isn't the first AI to attempt poetry. Last year, Google's Parsey McParseface made some poems of its own, although they were branded "wrongly" by reviewers. While it seems like AI is becoming more "intelligent" and less "artificial" all the time, when it comes to creativity, perhaps this is one job that software should leave to us humans.

    The dangers of drowsy (昏昏欲睡) driving have been widely known. Now several companies have developed face-tracking technology that can tell when drivers become dangerously sleepy.

    Here is how it might work: A camera in your car monitors your facial expression, compares it to a database of expressions and determines if you are likely sleepy or distracted. The car then alerts you to pay attention or pull over.

    Affectiva has developed emotion recognition technology that aims to detect when people are just starting to get tired. The idea is to catch the warning signs before drowsiness really strikes. "Actually, when someone is drowsy, that is too late." Gabi, vice president of Affectiva said. "What if you can see trends in someone's face about five minutes before they become sleepy?" Affectiva's program can recognize seven different emotions and 15 facial expressions. Its standards were developed by sifting (筛选) through a database of 4 million faces from 75 counties, said Zijderveld. She suggested that carmakers could coordinate (协调) the program's facial recognition data with oral reminders, such as sound warnings, or (nonverbal) alerts, like a change of temperature and vibrations (continuous slight shaking movements).

    Eyeris is another company working in facial analytics. Modar Alaoui, the company's CEO, said that its software detects "eye openness" in addition to other facial indicators. The software can also read head position, which may indicate when someone begins to nod off.

    These technologies aren't the first attempt to fight drowsiness behind the wheel. Inventors came up with the similar device "sleeper beeper" to prevent sleep in cars back in 1983. The sleeper beeper was attached to a driver's ear and would issue a noisy warning when the driver's head nodded past a certain point. But the latest software would intervene (干涉) earlier and more effectively.

As far as we know batteries are playing an important role in our life. We couldn't live without batteries. Why so? Batteries provide power for anything from small sensors to large systems. While scientists are finding ways to make them smaller but even more powerful, problems can arise when these batteries are much larger and heavier than the devices themselves. University of Missouri (MU) researchers are developing a nuclear energy source that is smaller, lighter and more efficient.

" To provide enough power, we need certain methods with high energy density (密度)", said Jae Kwon, assistant professor of electrical and computer engineering at MU." The radioisotope(放射性同位素) battery can provide power density that is much higher than chemical batteries."

Kwo n and his research team have been working on building a small nuclear battery, presently the size and thickness of a penny, intended to power various micro/ nanoelectromechanreal systems(M/NEMS). Although nuclear batteries can cause concerns, Kwon said, they are safe.

" People bear the word‘ nuclear' and think of something very dangerous," he said," However, nuclear power sources have already been safely powering a variety of devices, such as pace- makers, space satellites and underwater systems."

His new idea is not only in the battery's size, but also in its semiconductor(半导体). Kwon's battery uses a liquid semiconductor rather than a solid semiconductor.

" The key part of using a radioactive battery is that when you harvest the energy, part of the radiation energy can damage the lattice structure(晶体结构) of the solid semiconductor, Kwo n said," By using a liquid semiconductor, we believe we can minimize that problem."

Together with J. David Robertson, chemistry professor and associate director of the MU Research Reactor, Kwo n is working to build and test the battery. In the future, they hope to increase the battery's power, shrink its size and try with various other materials. Kwo n said that battery could be thinner than the thickness of human hair.