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.

    My father had returned from his business visit to London when I came in, rather late, to supper. I could tell at once that he and my mother had been discussing something. In that half-playful, half-serious way I knew so well, he said, "How would you like to go to Eton?"

    "You bet," I cried quickly catching the joke. Everyone knew it was the most expensive, the most famous of schools. You had to be entered at birth, if not before. Besides, even at 12 or 13, I understood my father. He disliked any form of showing off. He always knew his proper station in life, which was in the middle of the middle class, our house was medium-sized; he had avoided joining Royal Liverpool Golf Club and went to a smaller one instead; though once he had got a second-hand Rolls-Royce at a remarkably low price, he felt embarrassed driving it, and quickly changed it for an Austin 1100.

    This could only be his delightful way of telling me that the whole boarding school idea was to be dropped. Alas! I should also have remembered that he had a liking for being different from everyone else, if it did not conflict(冲突) with his fear of drawing attention to himself.

    It seemed that he had happened to be talking to Graham Brown of the London office, a very nice fellow, and Graham had a friend who had just entered his boy at the school, and while he was in that part of the world he thought he might just as well phone them. I remember my eyes stinging (刺痛) and my hands shaking with the puzzlement of my feelings. There was excitement, at the heart of great sadness.

"Oh, he doesn't want to go away," said my mother, "You shouldn't go on like this." "It's up to him," said my father. "He can make up his own mind."

    Winters are long and unforgiving in North Dakota. The winter of 1996 was especially brutal. It was a hard time in my own life too. A neck injury had kept me flat in bed for nearly a year. “Just in time for Easter,”my husband, Dick, said. But how could I feel the joy when the snow was four feet deep and I had months of painful physical treatment ahead?

    I was doing the dishes one day, feeling hopeless when there was a tap against the glass. It was a branch of the troublesome cottonwood (棉白杨).Back in the fall of 1979, it was a new subdivision (分支）then, an eight-foot stick. The people who'd briefly occupied the house before us had placed the pipe from the pump next to it. The earth was so wet that the poor thing had fallen down, most of its bare root system pointing skyward, and blowing hopelessly back and forth in the cold wind. Dick decided to pull it out one day, but I protested.

    “Look at how hard it's trying!” I said, pointing to the way it strongly kept hold of the earth. “It deserves a chance.”

     Dick borrowed some tools. We packed dry soil around the tree and put up some stakes (桩) into the ground, making it stand upright. That winter was still terrible. Surprisingly,in the spring my “rescue stick”put forth a few leaves,then with lots of branches. The year after that, we were able to remove the stakes. By the 1990s that little stick was a giant, towering over the house.

    Now the tapping at the window continued, louder as the wind picked up, almost as though to tell me to look up. At last, I did. I caught my breath. In the window against the icy blue sky, thousands and thousands of fresh red buds were waving in the wind.

    The tree was bursting with life and I had a wonderful Easter.

    Younger students experience school bullying (欺凌) more frequently than older ones, and male students are bullied more than their female peers, a survey found.

    It also found that nearly half of the students had been intentionally hit or knocked down by classmates. About 6 percent said they are targeted by bullies on campus every day. The survey also found that students from ordinary schools experienced more bullying than peers from key institutions, and children from poor families are more likely to be bullied at school.

    Being bullied can have a negative impact on a child's personal development and academic performance, according to Zhou Jinyan, a researcher who led the study at Beijing Normal University. 揅hildren being bullied will find it hard to trust others,? Zhou said. 揟hey may often feel anxiety, anger, resentment or depression. These emotions will further undermine their ability to control their own life.”

    In recent years, bullying on Chinese campuses has been frequently reported and has attracted widespread attention and concern. The most recent incident to arouse heated discussions took place in December at Beijing's Zhongguancun No.2 Primary School. A fourth-grade student was bullied and laughed at by classmates, causing him acute stress disorder.

    The Supreme People's Procuratorate (最高人民检察院) received about 1,900 cases related to school bullying in 2016. Meanwhile, there was a notable increase in bullying reports involving middle school students from 14 to 18 years old.

    Zhou came up with some ways to solve the problem, including boosting communication between teachers, parents and students and trying to establish more harmonious relationships among children. She said it was strongly suggested that parents try to be involved in their children's educational experience, as their presence and companionship have proved effective in reducing bullying and its negative effects.

    As Internet users become more dependent on the Internet to store information, are people remembering less? If you know your computer will save information, why store it in your own personal memory, your brain? Experts are wondering if the Internet is changing what we remember and how.

    In a recent study, Professor Betsy Sparrow conducted some experiments. She and her research team wanted to know the Internet is changing memory. In the first experiment, they gave people 40 unimportant facts to type into a computer. The first group of people understood that the computer would save the information. The second group understood that the computer would not save it. Later, the second group remembered the information better. People in the first group knew they could find the information again, so they did not try to remember it.

    In another experiment, the researchers gave people facts to remember, and told them where to find the information on the Internet. The information was in a specific computer folder(文件夹). Surprisingly, people later remember the folder location(位置)better than the facts. When people use the Internet, they do not remember the information. Rather, they remember how to find it. This is called “transactive memory”.

    According to Sparrow, we are not becoming people with poor memories as a result of the Internet. Instead, computer users are developing stronger transactive memories; that is, people are learning how to organize large amounts of information so that they are able to find it at a later date. This doesn't mean we are becoming either more or less intelligent, but there is no doubt that the way we use memory is changing.

    Do you like to show off your expensive items? You could find yourself without friends! Scientists prove that expensive status symbols make you look less socially attractive.

    Items such as a fancy car and a Rolex watch are often thought to increase our social standing(地位) and often come with a high price tag(标签).According to the latest research, however, it has the opposite effect and people would prefer to be friends with someone who places less value on material objects.

    "Often we think that status symbols will make us look more socially attractive to others," says Stephen Garcia, the study's leading author from the University of Michigan. He adds, "However, our research suggests that these status signals actually make us look less socially attractive.

    The researchers conducted six studies which assessed how people presented themselves and how people viewed strangers. People who chose to wear higher status items tended to get a negative response, but people wanted to be friends with people who preferred lower status symbols.

    The study took the role of the luxury(奢侈) item to see if it was possible that the expensive item itself played a part in people's reactions. The definition of a status symbol changed based on a person's socioeconomic status, but the same effect of keeping off potential friends was seen regardless of social position.

    "At a social level, we may be wasting billions of dollars on expensive status symbols that finally keep others from wanting to associate with us, "says Kimberlee Weaver Livnat at the University of Haifa. She says, "And to the extent that close friendships are important to well-being, and we may be unintentionally hurting ourselves."

    However, Patricia Chen of the National University of Singapore said this does not necessarily mean status symbols are a bad thing. She says, "Our findings right now only apply to the formation of new friendships. Status symbols may be beneficial at other times and in other settings, such as when trying to establish new business contacts."