Since the 1970s, scientists have been searching for ways to link the brain with computers. Brain-computer interface (界面) (BCI) technology could help people with disabilities send commands to machines.

    Recently, two researchers, Jose Milan and Michele Tavella from the Federal Polytechnic schooling Lausanne, Switzerland, demonstrated(展示)a small robotic wheelchair directed by a person's thoughts.

    In the laboratory, Tavella operated the wheelchair just by thinking about moving his left or right hand. He could even talk as he watched the vehicle and guided it with his thoughts.

    "Our brain has billions of nerve cells. These send signals through the spinal cord(脊髓)to the muscles to give us the ability to move. But spinal cord injuries or other conditions can prevent these weak electrical signals from reaching the muscles," Tavella says.  "Our system allows disabled people to communicate with external world and also to control devices."

The researchers designed a special cap for the user. This head cover picks up the signals from the scalp(头皮) and sends them to a computer. The computer interprets the signals and commands the motorized wheelchair. The wheelchair also has two cameras that identify objects in its path. They help the computer react to commands from the brain.

    Prof. Milan, the team leader, says scientists keep improving the computer software that interprets brain signals and turns them into simple commands. "The practical possibilities that BCI technology offers to disabled people can be grouped in two categories: communication, and controlling devices. One example is this wheelchair."

    He says his team has set two goals. One is testing with real patients, so as to prove that this is a technology they can benefit from. And the other is to guarantee that they can use the technology over long periods of time.

    People around the world are superstitious about numbers; even those ancient Greeks believed that all numbers and their multiples had some mystical significance.

    Those numbers between 1 and 13 were in particular to have a powerful influence over the affairs of men.

    For example, it is commonly said that luck, good or bad, comes in threes; if an accident happens, two more of the same kind may be expected soon afterwards. The arrival of a letter will be followed by two others within a certain period.

    Another belief involving the number three has it that it is unlucky to light three cigarettes from the one match. If this happens, the bad luck that goes with the deed falls upon the person whose cigarette was the last to be lit. The ill-men linked to the lighting of three things from one match or candle goes back to at least the 17th century and probably earlier. It was believed that three candles alight at the same time would be sure to bring bad luck; one, two, or four, were permissible, but never just three.

    Seven was another significant number, usually regarded as a bringer of good luck. The ancient astrologers believed that the universe was governed by seven planets; students of Shakespeare will recall that the life of man was divided into seven ages. Seven horseshoes nailed to a house will protect it from all evil.

    Nine is usually thought of as a lucky number because it is the product of three times three. It was much used by the Anglo Saxons in their charms for healing.

    Another belief was that great changes occurred every 7th and 9th of a man's life. Consequently, the age of 63 (the product of nine and seven) was thought to be a very perilous time for him. If he survived his 63rd year he might hope to live to a ripe old age.

    Thirteen, as we well know, is regarded with great awe and fear. The common belief is that this derives from the fact that there were 13 people at Christ's Last Supper. This being the eve of his betrayal, it is not difficult to understand the significance given to the number by the early Christians.

    In more modern times 13 is an especially unlucky number of a dinner party, for example. Hotels will avoid numbering a floor the 13th; the progression is from 12 to 14, and no room is given the number 13. Many home owners will use 12 1/2 instead of 13 as their house number.

    Yet oddly enough, to be born on the 13th of the month is not regarded with any fear at all, which just shows how irrational we are in our superstitious beliefs.

    Welcome to your future life!

    You get up in the morning and look into the mirror. Your face is firm and young-looking. In 2035, medical technology is better than ever. Many people your age could live to be 150, so at 40, you're not old at all. And your parents just had an anti-aging(抗衰老的) treatment. Now, all three of look the same age!

    You say to your shirt, “Turn red.” It changes from blue to red. In 2035, “smart clothes” contain particles(粒子) much smaller than the cells in your body. The particles can be programmed to change clothes' color or pattern.

    You walk into the kitchen. You pick up the milk, but a voice says,“ You shouldn't drink that!” Your fridge has read the chip (芯片) that contains information about the milk , and it knows the milk is old . In 2035, every article of food in the grocery store has such a chip.

    It's time to go to work. In 2035, cars drive themselves. Just tell your “smart car” where to go. On the way, you can call a friend using your jacket sleeve. Such “smart technology” is all around you.

    So will all these things come true? “For new technology to succeed,” says scientist Andrew Zolli ,”it has to be so much better that it replaces what we have already.” The Internet is one example—what will be the next?

    People and animals often enjoy loving relationships with each other. When people adopt domesticated (家养的) animals into their families as pets, animals give humans the blessings of companionship and fun in return. In the wild, animals sometimes carry out dramatic rescues of people in dangerous situations, miraculously (奇迹般地) sensing human needs and jumping in without fear to help.

    In 2000, a 6-year-old boy unified Elian Gonzalez left Cuba on a boat bound for Florida in the United States, but the boat sank and everyone aboard drowned except Elian and two adults. Elian and the other two survivors held onto inner tube for 48 hours to try to stay afloat in the sea. After a while, however, Elian began to lose strength, slipping under the water and then grabbing the tube again as he fought to stay alive.

    A small group of dolphins noticed Elian struggling and swan over to him to help. The dolphins formed a circle around the inner tube and took turns using their noses to lift Elian until fishermen working in the area discovered and rescued Elian and the two adults who floated nearby. The fishermen reported that, when they discovered Elian, he was repeating a prayer that his mother had taught him before drowning, asking guardian angels to protect him.

    Miraculously, the dolphins knew that a child would need more help than adults, so they focused on Elian — and they figured out exactly what needed to be done and cooperated to carry out that plan successfully. They made it!

    A few weeks ago, I called an Uber to take me to the Boston airport for a flight home for the holidays. As I slid into the back seat of the car, the warm intonations(语调) of the driver's accent washed over me in a familiar way.

    I learned that he was a recent West African immigrant with a few young children, working hard to provide for his family. I could relate: I am the daughter of two Ethiopian immigrants who made their share of sacrifices to ensure my success. I told him I was on a college break and headed home to visit my parents. That's how he found out I go to Harvard. An approving eye glinted at me in the rearview window, and quickly, we crossed the boundaries of rider and driver. I became his daughter, all grown up — the product of his sacrifice.

    And then came the fateful question: "What do you study?" I answered "history and literature" and the pride in his voice faded, as I knew it might. I didn't even get to add "and African-American studies" before he cut in, his voice thick with disappointment, "All that work to get into Harvard, and you study history?"

    Here I was, his daughter, squandering the biggest opportunity of her life. He went on to deliver the age-old lecture that all immigrant kids know. We are to become doctors (or lawyers, if our parents are being generous) — to make money and send money back home. The unspoken demand, made across generations, which my Uber driver laid out plainly, is simple: Fulfill your role in the narrative(故事) of upward mobility so your children can do the same.

    I used to feel anxious and backed into a corner by the questioning, but now as a junior in college, I'm grateful for their support more than anything. This holiday season, I've promised myself I won't huff and get annoyed at their inquiries. I won't defensively respond with "but I plan to go to law school!" when I get unrequested advice. I'll just smile and nod, and enjoy the warmth of the occasion.