Life in the Clear

    Transparent animals let light pass through their bodies the same way light passes through a window. These animals typically live between the surface of the ocean and a depth of about 3,300 feet—as far as most light can reach. Most of them are extremely delicate and can be damaged by a simple touch. Sonke Johnsen, a scientist in biology, says, “These animals live through their life alone. They never touch anything unless they're eating it, or unless something is eating them.”

    And they are as clear as glass. How does an animal become see-through? It's trickier than you might think.

    The objects around you are visible because they interact with light. Light typically travels in a straight line. But some materials slow and scatter(散射) light, bouncing it away from its original path. Others absorb light, stopping it dead in its tracks. Both scattering and absorption make an object look different from other objects around it, so you can see it easily.

But a transparent object doesn't absorb or scatter light, at least not very much, Light can pass through it without bending or stopping. That means a transparent object doesn't look very different from the surrounding air or water. You don't see it —-you see the things behind it.

    To become transparent, an animal needs to keep its body from absorbing or scattering light. Living materials can stop light because they contain pigments(色素) that absorb specific colors of light. But a transparent animal doesn't have pigments, so its tissues won't absorb light. According to Johnsen, avoiding absorption is actually easy. The real challenge is preventing light from scattering.

Animals are built of many different materials—-skin, fat, and more—-and light moves through each at a different speed. Every time light moves into a material with a new speed, it bends and scatters. Transparent animals use different tricks to fight scattering. Some animals are simply very small or extremely flat. Without much tissue to scatter light, it is easier to be see—through. Others build a large, clear mass of non-living jelly-lie(果冻状的)material and spread themselves over it .

    Larger transparent animals have the biggest challenge, because they have to make all the different tissues in their bodies slow down light exactly as much as water does. They need to look uniform. But how they're doing it is still unknown. One thing is clear for these larger animals, staying transparent is an active process. When they die, they turn a non-transparent milky white.

    Two summers ago I was about to turn fifty and wanted to do something I'd never done before. My daughter Bailey thought skydiving (跳伞) would be perfect for me. I can promise you that of all the things I was thinking of doing, jumping out of an airplane never came close to making the list. As I age, I seem to have developed a growing fear of heights.

    After several requests from my daughter, I finally said yes and she looked almost shocked. I told a friend what we were doing, then we set off. We had a 3-hour drive to the jump site. We drove through some beautiful countryside, but then we passed a small cemetery(墓地). Then we passed another cemetery and another one. I asked if so many people died jumping out of airplanes in this area that they needed to keep building more cemeteries to bury all the bodies!

    As we squeezed into the little plane, I tightly held the right hand of my partner Ronnie. The short ride to altitude was cruel for me. As Bailey stepped to the door, she looked back at me and said “Dad, I'm sure you can do it!” I said yes as she rolled out. I immediately looked behind me and said “RONNIE I AM NOT FEELING GOOD!” He said, “It's going to be great. Besides, it's too late now anyway”, and we jumped out.

    The next five minutes were some of the most amazing of my life. It was so beautiful and peaceful—except for the parts where I was screaming. I prayed to God for the parachute (降落伞) to open, but mostly I told Him how thankful I was for my life and being with me through good and bad.

    Years ago, I lived in a building in a large city. The next building was only a few feet away from mine. There was a woman who lived there, whom I had never met, yet I could see her seated by her window each afternoon, sewing or reading.

    After several months had gone by, I began to notice that her window was dirty. Everything was unclear through the dirty window. I would say to myself, “I wonder why that woman doesn't wash her window. It really looks terrible.”

    One bright morning I decided to clean my flat, including washing the window on the inside.Late in the afternoon when I finished the cleaning, I sat down by the window with a cup of coffee for a rest. What a surprise! Across the way, the woman sitting by her window was clearly visible. Her window was clean!

    Then it dawned on me. I had been criticizing her dirty window, but all the time I was watching hers through my own dirty window.That was quite an important lesson for me. How often had I looked at and criticized others through the dirty window of my heart, through my own shortcomings?

    Since then, whenever I wanted to judge someone, I asked myself first, “Am I looking at him through my own dirty window?” I try to clean the window of my own world so that I may see the world about me more clearly.

    Festivals are a great way to experience a destination in a different way. This article will fuel your wanderlust（漫游癖）and guide you to the best festivals.

    St Patrick's Day

    Where: Dublin, Ireland & New York, USA

    When: 17 March

    St Patrick's Day has taken place in New York city on March 17th since 1762. On this day, the whole city turns green. Many Irish make traditional bread on this day. It is one of the most fun days the of the year in New York City every year, when the whole city turns into a big green party.

    SXSW

    Where: Austin, USA

    When: 10-19 March

    Like free things? Yeah me too! Free food, drink and music sound good? Welcome to Austin, Texas. SXSW is a festival for those who work in the music and film industries. There are "free" shows. You di have to pay but not by handing over cash; you have to give some time to queue but it is worth it to see some popular stars.

    King's Day

    Where: Amsterdam, Netherlands

    When: 27 April

    Every year on April 27 Amsterdam turns a very bright color of orange for King's Day, which is the birthday of King Willem-Alexander. It is a crazy fun celebration when the center of the city is car, bus, and bike-free. It is a market day, when anyone can sell pretty much anything. Tips: Take a jacket with you, wear orange, and bring cash.

    Just for Laughs

    Where: Montreal, Canada

    When: 14-30 July

    For comedy lovers there is no other festival in the world better than Montreal's Just for Laughs. The festival concentrates most of its shows in the Latin Quarter. During the day street performers delight the crowds and at night the city comes alive with comedy all over the city.

    The annual World Economic Forum took place in Davos, Switzerland, in Jan. 23-26, 2018. What did Chinese entrepreneurs （企业家）speak in the forum? Are there some quotable quotes for you?

    Jack Ma, founder and executive chairman of Alibaba Group

    "I think globalization cannot be stopped — no one can stop globalization, no one can stop trade. If trade stops, the world stops. Trade is the way to dissolve (结束) the war not cause the war," said Ma in Davos, "Google, Facebook, Amazon and Alibaba — we are the luckiest companies of this century. But we have the responsibility to have a good heart, and do something good."

    Richard Liu, founder and chief executive officer of JD

    "Business is not only a way to make money but also a way to contribute yourself, to help people," Liu said in a speech in Davos. "How can we face the fractured (分化的) world? That's the topics of the Davos this year. I think a very important thing in business is cooperation. If we can unite, work together, if we work very closely, I think we can bring more hope to the people and we can build more trust between the people, countries and companies and partners," he said.

    Jane Sun, CEO of Ctrip

    "Tourism is a sunrise industry. Since I entered Ctrip, every year there are new comers, which, first of all, shows that tourism is booming." Sun told Sina.com in Davos. "We invested heavily in ABC. A refers to AI, B is big data, and C is cloud computing. As we continue to expand overseas, these three will be very good weapons for us. So we think those mean opportunity," she said.

    Hu Xiaoming, president of Aliyun

    "In 2018, people will see the development in various countries more closely connected with cloud computing. More manufacturing enterprises and financial institutions will start to use ‘cloud', and cloud computing will increase the efficiency of technology and finance," Hu told Xinhua in Davos.

    Are you sometimes a little tired and sleepy in the early afternoon? Many people feel this way after lunch. They may think that eating lunch is the cause of the sleepiness. Or, in summer, they may think it is the heat. However, the real reason lies inside their bodies. At that time—about eight hours after you wake up—your body temperature goes down. This is what makes you slow down and feel sleepy. Scientists have tested sleep habits in experiments where there was no night or day. The people in these experiments almost always followed a similar sleeping pattern. They slept for one long period and then for one short period about eight hours later.

    In many parts of the world, people take naps (小睡) in the middle of the day. This is especially true in warmer climates, where the heat makes work difficult in the early afternoon. Researchers are now saying that naps are good for everyone in any climate. A daily nap gives one a more rested body and mind and therefore is good for health in general. In countries where naps are traditional, people often suffer less from problems such as heart disease. Many working people, unfortunately, have no time to take naps. Though doctors may advise taking naps, employers don't follow it! If you do have the chance, however, here are a few tips about making the most of your nap. Remember that the best time to take a nap is about eight hours after you get up. A short sleep too late in the day may only make you feel more tired and sleepy afterward. This can also happen if you sleep for too long. If you do not have enough time, try a short nap—even ten minutes of sleep can be helpful.