On a stormy day last August, Tim heard some shouting. Looking out to the sea carefully, he saw a couple of kids in a rowboat were being pulled out to sea.

Two 12-year-old boys, Christian and Jack, rowed out a boat to search a football. Once they'd rowed beyond the calm waters, a beach umbrella tied to the boat caught the wind and pulled the boat into open water. The pair panicked and tried to row back to shore. But they were no match foritand the boat was out of control.

    Tim knew it would soon be swallowed by the waves.

“Everything went quiet in my head,” Tim recalls（回忆）. “I'm trying to figure out how to swim to the boys in a straight line.”

    Tim took off his clothes and jumped into the water. Every 500 yards or so, he raised his head to judge his progress. “At one point, I considered turning back,” he says. “I wondered if I was putting my life at risk.” After 30 minutes of struggling, he was close enough to yell to the boys, “Take down the umbrella!”

    Christian made much effort to take down the umbrella. Then Tim was able to catch up and climb aboard the boat. He took over rowing, but the waves were almost too strong for him.

“Let's aim for the pier（码头）,” Jack said. Tim turned the boat toward it. Soon afterward, waves crashed over the boat, and it began to sink. “Can you guys swim?” he cried. “A little bit,” the boys said.

Once they were in the water, Tim decided it would be safer and faster for him to pull the boys toward the pier. Christian and Jack were wearing life jackets and floated on their backs. Tim swam toward land as water washed over the boys' faces.

    “Are we almost there?” they asked again and again. “Yes,” Tim told them each time.

    After 30 minutes, they reached the pier.

    Self-driving vehicles will rely on cameras, sensors and artificial intelligence (AI) to recognize and respond to road and traffic conditions, but sensing is the most effective for objects and movement in the neighborhood of the vehicle. Not everything important in a car's environment will be caught by the vehicle's camera. Another vehicle approaching at high speed on a collision (碰撞) track might not be visible until it's too late. This is why vehicle-to-vehicle communication is undergoing rapid development. Our research shows that cars will need to be able to chat and cooperate on the road, although the technical challenges are considerable.

    Applications for vehicle- to-vehicle communication range from vehicles driving together in a row, to safety messages about nearby emergency vehicles. Vehicles could alert each other to avoid collisions or share notices about passers-by and bicycles.

    From as far as several hundred meters away, vehicles could exchange messages with one another or receive information from roadside units (RSUs) about nearby incidents or dangerous road conditions through 4G network. A high level of AI seems required for such vehicles, not only to self-drive from A to B, but also to react intelligently to messages received. Vehicles will need to plan, reason, strategize and adapt in the light of information received in real time and to carry out cooperative behaviors. For example, a group of autonomous vehicles might avoid a route together because of potential risks, or a vehicle could decide to drop someone off earlier due to messages received, a foreseen crowding ahead.

    Further applications of vehicle- to-vehicle communication are still being researched, including how to perform cooperative behavior.

    Most people looking for ways to quit smoking worry about weight gain, and with good reason. Smokers who quit tend to pack on an average of 5 pounds after they stop smoking cigarettes. A new study, published by the journal Science, explains why this happens.

    The new research explains that nicotine appears to combine with appetite-regulating neurons (调节食欲的神经元) in the brain, besides the receptors (感受器) that bring about addiction. These neurons help regulate how much food gets consumed, but under the influence of nicotine, they lose their self-control. This is why when smokers quit, they tend to eat more and gain weight.

    The researchers believe that their discovery will lead to the development of drugs that aim at nicotine receptors on brain cells that control appetite. In the future, weight gain may no longer be a reason for smokers to delay the decision to kick the habit, but that's no reason to wait. Nicotine-replacement treatment, while not for everyone, can help. Here are a few more ways to quit smoking and stay slim.

    Drink water. To improve metabolic (新陈代谢的) rates, make half of those glasses ice water. Juice can be too high in calories, something you'll want to keep an eye on your journey toward being a slimmer non-smoker. Plan your snacks. Healthy snacks help keep your metabolism working, so you continue to burn calories while stopping wild hunger pain, or fake hunger.

    Keep moving. Exercise kills two birds with one stone. It helps you burn calories and prevents you from eating when you're not truly hungry. It's also a feel-good stress reliever (缓解物). Focus on your fitness and how being healthy makes you feel. Make exercise a goal and think of quitting as your reward for being physically fit.

    "Don't answer it," I said to Sam. Our door in the inner city is constantly knocked on; our previous door in the suburbs rarely so. Sam has a full-time job and cannot spend his days answering requests to fix leaking baths or carry cash to the bank.

    Sam opened the door and it was Mervin.

    "There's a bird on the second floor," he said. "It's in trouble."

    Sam followed Mervin upstairs. Mervin pointed and turned to let Sam look. It was a pigeon, the most common of all birds, the bird most likely to foul (弄脏) your newly washed car. And it wasn't flying away. It was stamping in circles. As Sam bent to look, Mervin coughed, "Number two."

    Sam asked him to repeat that. "Number two," Mervin said. "The pigeon has been sitting in his own number two, and now it's stuck to his foot."

It had rained for five days, and the bird was young. It could have been sheltering in a     wet nest of its own waste, which had then dried on its foot, preventing it from flying away. The pigeon moved in a few more circles. Sam bent to take another look. Mervin said, "All right, then." and walked away.

    "Why does everyone think you must solve the problems around here?" I said to Sam when he returned with his story. "It's a bird. Just leave it on the stairs, and let nature take its course." Sam didn't agree. Then he went to the garage and emptied the cardboard box containing our imported camping mats. He returned with the gray pigeon in the box. He showed the bird to our children and they decided to keep it.

    They put its foot in the warm water bath and got rid of its waste. Immediately the pigeon erupted in a bomb of feathers and began flying.

    The UNESCO has recognized the Chinese art of paper cutting on its Intangible Cultural Heritage List. But paper cutting is at the risk of disappearing.

    Voyo Woo, a Chinese immigrant, who loves paper cutting, worked hard to celebrate the ancient art form. With a keen interest in paper cutting, Ms Woo held a paper cutting exhibition at a shopping center near Washington. "I really love it. I get so much fun by doing it. So I'm just kind of hoping that more people will learn about this art which is about to disappear. I think it's time to take action. So I held it."

    Voyo Woo began to study paper cutting when she was a 14-year-old girl in southeastern China. Voyo Woo's teacher gave her extra training after class because Voyo Woo discovered a special love for it. Later, her beautiful paper cuttings won second prize in a national painting competition. "Paper is the easiest material that you can find. You can just turn it into beautiful art. I think it is like magic to me."

    Ms Woo came to the US after she finished college in 2008. She has been invited to show the art at a wide collection of events. She also has shown her skill and works at famous museums like the Smithsonian Institution's Freer and Sackler art galleries in Washington.

    "I saw so many people coming to me and asking me. They were amazed. I think it's important to introduce the art form to American people or anyone who is interested."

    Ms Woo placed examples of her art around her as she displayed paper cutting at the shopping center. Ann Russ, a shopper, was attracted by the nature of the work. She said it put her at ease. "I like to know about Chinese art, specifically because it's almost relaxing to put that much effort into it," Russ said.

    In March 2008, I told my friends: I was going to shut down my law practice and travel around the world in a year. What's more, I'd do it without taking any flights or making a single advance (预先的) reservation. Some friends offered support and encouragement, while others were doubtful. Once I'd said the words, there was no turning back. It took months to shut down my law practice and get things in order.

    There really wasn't any great reason why I wanted to circle the world. I simply wanted to do something fun and different. When I had this plan, I didn't plan for it to lead to a life on the road forever. I was planning to come back, open a new law practice and write a hugely successful book about my travels. Before I left, I started a travel blog, which served as a way to take notes for the book.

    Once I set off on my trip in December 2008, I found that travelling without using planes was not easy. It took seven days and nights on trains to get from Moscow to Beijing. Sometimes, I wouldn't see a village or a human being for 10 hours. I had a whole cabin to myself from the second day of that journey.

    It turned out that travelling with no reservations was far less difficult than I had imagined. Pulling into a city on a bus with a bag, looking in a guidebook for a few suggestions of accommodations (住宿), and then finding an empty room was never a problem.

    Soon after I started this adventure, I realised that my return to the US would be temporary (暂时的). About three months into my journey, I realised that I didn't want to go back to my old life. The world is so wonderful and I wanted to see as much of it as I could.