Dreams can be familiar and strange, fantastical or boring, but some dreams might be connected to the mental processes that help us learn. In a recent study, scientists found a connection between nap time dreams and better memory in people who were learning a new skill.

    In the study, 99 college students between the ages of 18 and 30 each spent an hour on a computer, trying to get through a virtual maze (逃宫). The maze was difficult, and the study participants had to start in a different place each time they tried, making it even more difficult. They were also told to find a particular picture of a tree and remember where it was.

    For the first 90 minutes of a five - hour break, half of the participants stayed awake and half were told to take a short nap. Participants who stayed awake were asked to describe their thoughts. Participants who took a nap were asked about their dreams after sleep and they were awakened within a minute of sleep to describe their dreams.

    Stickgold, a neuroscientist, wanted to know what people were dreaming about when their eyes weren't moving during sleep.Four of the 50 people who slept said their dreams were connected to the maze. Some dreamed about the music that had been playing when they were working; others said they dreamed about seeing people in the maze. When these four people tried the computer maze again, they were able to find the tree faster than before their naps.

    Stickgold suggests the dream itself doesn't' help a person learn, it's the other way around. He suspects that the dream was caused by the brain processes associated with learning.

    All four of the people who dreamed about the task had done poorly the first time,which makes Stickgold wonder if the dreams show up when a person finds a new task particularly difficult. People who had other dreams, or people who didn't' take a nap, didn't show the same improvement.

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    In 1812, the year Charles Dickens was born, there were 66 novels published in Britain. People had been writing novels for a century—most experts date the first novel to Robinson Crusoe in 1719—but nobody wanted to do it professionally. The steam-powered printing press was still in its early stages; the literacy（识字） rate in England was under 50%. Many works of fiction appeared without the names of the authors, often with something like "By a lady." Novels, for the most part, were looked upon as silly, immoral, or just plain bad.

    In 1870, when Dickens died, the world mourned him as its first professional writer and publisher, famous and beloved, who had led an explosion in both the publication of novels and their readership and whose characters — from Oliver Twist to Tiny Tim— were held up as moral touchstones. Today Dickens' greatness is unchallenged. Removing him from the pantheon（名人堂） of English literature would make about as much sense as the Louvre selling off the Mona Lisa.

    How did Dickens get to the top? For all the feelings readers attach to stories, literature is a numbers game, and the test of time is extremely difficult to pass. Some 60,000 novels were published during the Victorian age, from 1837 to 1901; today a casual reader might be able to name a half-dozen of them. It's partly true that Dickens' style of writing attracted audiences from all walks of life. It's partly that his writings rode a wave of social, political and scientific progress. But it's also that he rewrote the culture of literature and put himself at the center. No one will ever know what mix of talent, ambition, energy and luck made Dickens such a singular writer. But as the 200th anniversary of his birth approaches, it is possible — and important for our own culture—to understand how he made himself a lasting one.

    Like all big cities, Paris has a traffic problem: lots of cars, lots of traffic jams and lots of pollution from exhaust fumes (废气). So the city began a project to improve the situation.

    Under the Velib project ('Velib' comes from vélo liberté, or 'bicycle freedom') people can take a bicycle, use it for as long as they want, and then leave it at the same or another bicycle station. The first half-hour on the bike is free, but if you don't return it after 30 minutes, you have to pay. But it's only €1 a day or €29 a year! The bicycles are heavy (25 kg), and they are all grey and have baskets. There are about 20,000 of them in the city, and around 1,450 bicycle stations. So there are a lot more Velib stations than the 298 subway stations!

    Paris is not the first city to have a project like this. But not everybody thinks it's a great idea. One Parisian said, “These bicycles are only for short journeys. If people want to travel across the city, they won't use a bicycle — they'll still use their cars.”

    A city spokesman said, “The bicycle project won't solve all our traffic problems, of course. But it might help reduce air pollution. Traffic, together with factory fumes, is a big problem. There aren't any simple answers to traffic problems and pollution in cities. But unless we do something now, there will be more traffic jams and temperatures will continue to rise, so the problems in our environment will get worse. The bikes might help people to lead a healthier life, too.”

    Anyone who cares about what schools and colleges teach and how their students learn will be interested in the memoir(回忆录)of Ralph W. Tyler, who is one of the most famous men in American education.

    Born in Chicago in 1902, brought up and schooled in Nebraska, the 19-year-old college graduate Ralph Tyler became hooked on teaching while teaching as a science teacher in South Dakota and changed his major from medicine to education.

    Graduate work at the University of Chicago found him connected with honorable educators Charles Judd and W. W. Charters, whose ideas of teaching and testing had an effect on his later work. In 1927, he became a teacher of Ohio State University where he further developed a new method of testing.

    Tyler became well-known nationally in 1938, when he carried his work with the Eight-Year Study from Ohio State University to the University of Chicago at the invitation of Robert Hutchins.

    Tyler was the first director of the Center for Advanced Study in the Behavioral Sciences at Stanford, a position he held for fourteen years. There, he firmly believed that researchers should be free to seek an independent(独立的)spirit in their work.

    Although Tyler officially retired in 1967, he never actually retired. He served on a long list of educational organizations in the United States and abroad. Even in his 80s he traveled across the country to advise teachers and management people on how to set objectives(目标)that develop the best teaching and learning within their schools.

News 1

    Yuan Longping, the father of hybrid rice, won the World Food Prize on Monday. Yuan developed the world's first popular and widely known hybrid rice. Hybrid rice plants can make more rice than regular ones.

News 2

    Have you ever got angry at books that are full of mistakes? Don't worry, things will get better soon. Last week, China started checking textbooks, dictionaries and children's books all over the country. The government said the results of the check would come out at the end of June.

News 3

    People will see a new "star" in the sky soon. China plants to send a satellite into space by December 2006.It will stay in space for one year. It will go around the moon and take pictures. It must be very expensive, right? That's for sure; 1.4 billion yuan!

News 4

    Have you ever thought of being able to fly around the world in a few hours? One day, maybe you can. Last Saturday, the American X­43A airplane made its first flight. It reached a speed of 8,000 kilometers per hour. This makes it the fastest plane in the world. X­43A is only three to four meters long, but it's very heavy. It weighs 1,270 kilograms.

    Plastics remain one of the most - used materials for making many things. Things made of plastics can be very strong and last a long time. Plastics are also much lighter than metal and can easily be formed into different shapes. Plastics can take hundreds of years to break down on their own. And very few kinds are highly recyclable.

    A team of researchers working at the US Department of Energy says it has created a kind of plastic that could lead to products that are 100 percent recyclable. It recently reported the discovery in a study in the journal Nature Chemistry.

    The researchers say the new material is a plastic polymer (聚合体)called polydiketoenamine, or PDK. The team reports the material can be broken down in parts at the molecular (分子的)level. It can then be built up again to form plastics of different shapes, textures and colors. The researchers say this process can be repeated over and over again—without the plastic material losing any performance or quality.

    "Most plastics were never made to be recycled," lead researcher Peter Christensen said in a statement. " But we have discovered a new way to assemble plastics that takes recycling into consideration from a molecular perspective. "

    Many plastics have different chemicals added to them to make them more useful and powerful. The problem is that these chemicals attach to the monomers (单体), which remain in plastics even after the material gets processed at a recycling plant. The research team reported that, with the newly discovered PDK material, the monomers could be recovered and separated from any chemical additives.

    Next, the researchers plan to develop PDK plastics "with a wide range of thermal and mechanical properties. These plastics could be used for many kinds of cloth, as well as things such as 3D printed materials and foams. In addition, the team is trying to include plant - based materials in the process.