When she looked ahead，Florence Chadwick saw nothing but a solid wall of fog.Her body was numb (麻木的)．She had been swimming for nearly sixteen hours.

    Already she was the first woman to swim the English Channel in both directions.Now，at age 34，her goal was to become the first woman to swim from Catalina Island to the California coast.

    On the morning of July 4th，1952，the sea was like an ice bath and the fog was so thick that she could hardly see her support boats.The wind was strong and it was raining heavily.Against the cold water of the sea，she struggled on—hour after hour.Millions of people at home were watching her in front of the television.

    In one of the boats，her mother and her trainer tried their best to encourage her.They told her it wasn't much farther.But all she could see was fog.They urged her not to give up.She never had...until then.With only a half mile to go，she asked to be pulled out.

    After thawing her cold body several hours later，she told a reporter，“Look，I'm not excusing myself，but if I could have seen land I might have made it.” It was not tiredness or even the cold water that defeated her.It was the fog.She was unable to see her goal.

    Two months later，she tried again.This time，despite the same thick fog，she swam with all her strength and her goal clearly pictured in her mind.She knew that somewhere behind that fog was land and this time she made it! Florence Chadwick became the first woman to swim the Catalina Channel!  

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STANFORD UNIVERSITY

    When I was in the eighth grade, one caring teacher of mine taught me several useful little techniques. He told me to keep a notebook nearby when I was reading and that I should try to figure out what the main idea of every paragraph was so that I could understand the passages better. It seemed awfully boring at that time, but I decided to give it a try anyway.

    It didn't take long before I started reading a book called How to Read a Book that would completely change how I thought about the written word. Thanks to these techniques, I learned to get the most out of reading. I kept applying them over the years until I finally came up with a lot of little techniques for reading a book.

    I also eventually came to learn that there were a lot of different kinds of reading. For example, when I read a Stephen King novel, the interesting plot made me completely relaxed. Then there's reading to learn new things, which is what I do when I read personal finance books. There's also reading to understand and grow, which is easily the hardest and the most rewarding. The last kind of reading involves taking a piece of literature or a nonfiction book that you might read for simple pleasure and transforming it into something life-changing, or something that causes you to question some of your deeply-held ideas and beliefs.

    How to Read a Book really focuses on the latter two: books that you read to learn about a new topic or to learn a skill, and books that you read to learn about yourself. If you've ever been drawn to read to really improve yourself, this book is well worth the time to read even if it's a bit dry at times. Let's dig in.

    What happens inside the head of a soccer player who repeatedly heads a soccer ball. That question motivated a study of the brains of experienced players.

    Researchers at the Albert Einstein College of Medicine in New York selected 34 adults, men and women. All of the volunteers had played soccer since childhood and  now competed year﹣round in adult soccer leagues. Each filled out a detailed questionnaire developed especially for this study to determine how many times they had headed a soccer ball in the previous year, as well as whether they had experienced any known concussions in the past.

    Then the players completed computerized tests of their memory and other learning skills and had their brains scanned. using a complex new M.R.I. technique which can find structural changes in the brain that can't be seen during most scans.

    According to the data they presented, the researchers found that the  players who had headed the ball more than about 1, 100 times in the previous 12 months showed significant loss of white matter in parts of their brains involved with memory, attention and the processing of visual information, compared with players who had headed the ball less.

    This pattern of white matter loss is "similar to those seen in traumatic brain injury", like that after a serious concussion, the researchers reported, even though only one of these players was reported to have ever experienced a concussion.

    The players who had headed the ball about 1, 100 times or more in the past year were also generally worse at remembering lists of words read to them, forgetting the words far more often than players who had headed the ball less.

    Andrew Ritchie, inventor of the Brompton folding bicycle, once said that perfect portable bike would be "like a magic carpet... You could fold it up and put it into your pocket or handbag". Then he paused: "But you'll always be limited by the size of the wheels. And so far no one has invented a folding wheel."

It was a rare — indeed unique — occasion when I was able to put Ritchie right. A 19th-century inventor, William Henry James Grout, did in fact design a folding wheel. His bike, predictably named the Grout Portable, had a frame that was divided into two and a larger wheel that could be separated into four pieces. All the bits fitted into Grout's Wonderful Bag, a leather case.

    Grout's aim: to solve the problems of carrying a bike on a train. Now doesn't that sound familiar? Grout intended to find a way of making a bike small enough for train travel: his bike was a huge beast. And importantly, the design of early bicycles gave him an advantage: in Grout's day, tyres were solid, which made the business of dividing a wheel into four separate parts relatively simple. You couldn't do the same with a wheel fitted with a one-piece inflated(充气的) tyre.

    So, in a 21st-century environment, is the idea of the folding wheel dead? It is not. A British design engineer, Duncan Fitzsimons , has developed a wheel that can be folded into something like a slender ellipse(椭圆). From beginning to end, the tyre remains inflated.

    Will the young Fitzsimons's folding wheel make it into production? I have no idea. But his inventiveness shows two things. First, people have been saying for more than a century that bike design has reached its limit, except for gradual advances. It's as silly a concept now as it was 100 years ago: there's plenty still to go for. Second, it is in the field of folding bikes that we are seeing the most interesting inventions. You can buy a folding bike for less than £1,000 that can be knocked down so small that can be carried on a plane ——minus wheels, of course ——as hand baggage.

    Folding wheels would make all manner of things possible. Have we yet got the magic carpet of Andrew Ritchie's imagination? No. But it's progress.

A group of small, waggling (扭动) robots that communicate by flashing lights can make collective decisions. This is similar to the process bees use to reach an agreement on where to build their nest.

"We believe that in the near future there are going to be simple robots that will do jobs that we don't want to do, and it will be very important that they make decisions on their own," says Carmen Miguel at the University of Barcelona in Spain. She and her team tested how copying bees might help with that.

When bees go house-hunting, they communicate their preferred locations through a "waggle dance". The more a bee recommends one location, the longer and harder it waggles. Eventually other bees join them, and they reach an agreement when a majority are waggling together. Researchers previously translated this behavior into a mathematical model, and Miguel and her colleagues used it to program decision-making rules into small robots called kilobots.

Each kilobot with three thin legs had an infrared-light emitter (红外线发射器) and receiver, and a colored LED light. Within a group, kilobots could move around, turn clockwise or anticlockwise and use infrared signals to exchange information.

Ezequiel Ferrero at the University of Barcelona says that across all the experiments, kilobots reached an agreement within about half an hour, even when they didn't have many immediate neighbors to communicate with. He says that getting the right combination of how long they spend transmitting their message and how much they walk around allowed them to make a collective decision in the end.