“When I grow up， I want to be...”

    Almost all of us have thought about，or been asked to think about，our future careers. Our answers may differ greatly. Even now your aspirations(志向，抱负)may have changed from when you were in primary school.

    However，it seems that career choices aren't only based on personal taste. In a survey carried out by Teens， doctors，lawyers，and bankers were some of most popular careers that people said they hoped to follow. This is similar to a survey carried out in the UK in May 2016 by job website—Co.uk，in which medicine was the top choice among UK teenagers aged between 13 and 17.

    Medicine and law are two of the oldest and best known professions. Their prestige (威望) may come from the fact that doctors and lawyers are much­respected members of society，and they make good money. What's more， these professions are often seen as a sign of upward social class.

    It is equally unsurprising that banking is now one of the most common career choices. Youngsters worldwide think of banking and see the money rolling in. Wealth is increasingly becoming one of the most important indicators(标志) of a successful career.

    However，not every child has the makings of doctor， lawyer， or banker. They are those who see achievement and happiness in other areas. As the Teens' survey discovered，a variety of unconventional(非传统的) jobs—coffee shop owner，waiter at a fast food restaurant—are among teenagers' career choices. They can be equally interesting and rewarding jobs.

    With every choice comes responsibility and challenge，and all career paths require specific education and training，you have to learn to balance optimism(乐观主义)and confidence with being realistic about your particular talents and skills.

    There were smiling children all the way. Clearly they knew at what time the train passed their homes and they made it their business to stand along the railway, wave to complete strangers and cheer them up as they rushed towards Penang. Often whole families stood outside their homes and waved and smiled as if those on the trains were their favorite relatives. This is the simple village people of Malaysia. I was moved.

    I had always traveled to Malaysia by plane or car, so this was the first time I was on a train. I did not particularly relish the long train journey and had brought along a dozen magazines to read and reread. I looked about the train. There was not one familiar face. I sighed and sat down to read my Economics.

    It was not long before the train was across the Causeway and in Malaysia. Johore Baru was just another city like Singapore, so I was tired of looking at the crowds of people as they hurried past. As we went beyond the city, I watched the straight rows of rubber trees and miles and miles of green. Then the first village came into sight. Immediately I came alive; I decided to wave back.

    From then on my journey became interesting. I threw my magazines into the waste basket and decided to join in Malaysian life. Then everything came alive. The mountains seemed to speak to me. Even the trees were smiling. I stared at everything as if I was looking at it for the first time.

    The day passed fast and I even forgot to have my lunch until I felt hungry. I looked at my watch and was surprised that it was 3:00 pm. Soon the train pulled up at Butterworth. I looked at the people all around me. They all looked beautiful. When my uncle arrived with a smile, I threw my arms around him to give him a warm hug (拥抱). I had never done this before. He seemed surprised and then his weather-beaten face warmed up with a huge smile. We walked arm in arm to his car.

    I looked forward to the return journey.

C

Plastic-Eating Worms

    Humans produce more than 300 million tons of plastic every year. Almost half of that winds up in landfills(垃圾填埋场), and up to 12 million tons pollute the oceans. So far there is no effective way to get rid of it, but a new study suggests an answer may lie in the stomachs of some hungry worms.

    Researchers in Spain and England recently found that the worms of the greater wax moth can break down polyethylene, which accounts for 40% of plastics. The team left 100 wax worms on a commercial polyethylene shopping bag for 12 hours, and the worms consumed and broke down about 92 milligrams, or almost 3% of it. To confirm that the worms' chewing alone was not responsible for the polyethylene breakdown, the researchers made some worms into paste(糊状物) and applied it to plastic films. 14 hours later the films had lost 13% of their mass — apparently broken down by enzymes (酶) from the worms' stomachs. Their findings were published in Current Biology in 2017.

    Federica Bertocchini, co-author of the study, says the worms' ability to break down their everyday food — beeswax — also allows them to break down plastic. ＂Wax is a complex mixture, but the basic bond in polyethylene, the carbon-carbon bond, is there as well, ＂she explains, ＂The wax worm evolved a method or system to break this bond. ＂

    Jennifer DeBruyn, a microbiologist at the University of Tennessee, who was not involved in the study, says it is not surprising that such worms can break down polyethylene. But compared with previous studies, she finds the speed of breaking down in this one exciting. The next step, DeBruyn says, will be to identify the cause of the breakdown. Is it an enzyme produced by the worm itself or by its gut microbes(肠道微生物)?

    Bertocchini agrees and hopes her team's findings might one day help employ the enzyme to break down plastics in landfills. But she expects using the chemical in some kind of industrial process — not simply ＂millions of worms thrown on top of the plastic.＂

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-like (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.

When your boss calls and tells you to send $100,000 to a supplier, be on your toes. It could be a fake call. As if fake emails weren't enough, on the rise now is the deep fake audio (虚假音频) that can be cloned to sound almost real and perfect and is easy to create. "It's on the rise, and something to watch out for," says Vijay Balasubramaniyan, the CEO of a company called Pindrop.

Balasubramaniyan stated during a safety meeting how easy it is to use machine to create sentences that a person probably never said from recorded words. "All you need is five minutes of audio, and you can create fake audio," says Balasubramaniyan. Then, he showed a database (数据库) of voices, typed a sentence, and connected it to a famous people's name on the list. A few seconds later, he clicked "play", and it sounded quite real.

More costly are fake phone calls, where cheaters are able to fake the phone number of real contacts and make calls that result in workers sending off lots of money. He mentioned the example of a United Kingdom energy company in 2019 that got attacked by deep fake audio in a call that asked a worker to send $243,000 to a supplier. Reported by the Wall Street Journal, the worker was directed to pay it within an hour.

Balasubramaniyan says if you were to get that kind of call from a "boss" be doubtful and ask to call back right away to prove authenticity (真实性). Besides this, in his opinion, companies need to use more safety measures for keeping up with deep fake artificial intelligence (AI) that produces phone calls and software to check authenticity versus fake calls. "This is a threat that's waiting to happen," he says. "It's a very small number now, but it's very real."

That night, when Aksionov was lying on his bed and just beginning to sleep, someone came quietly and sat down on his bed. He peered(看) through the darkness and recognized Makar.

"What more do you want of me?" asked Aksionov. "Why have you come here?"

Makar Semyonovich was silent. So Aksionov sat up and said, "What do you want? Go away, or I will call the guard!"

Makar Semyonovich bent close over Aksionov, and whispered, "Ivan Dmitrich forgive me!"

"What for?" asked Aksionov.

"It was I who killed the merchant and hid the knife among your things. I meant to kill you, too, but I heard a noise outside, so I hid the knife in your bag and escaped out of the window."

Aksionov was silent, and didn't know what to say. Makar Semyonovich slid off the bed-shelf and knelt upon the ground. "Ivan Dmitrich" he said, "forgive me! I will confess that it was I who killed the merchant, and you will be released and can go to your home."

"It is easy for you to talk," said Aksionov "but I have suffered for you these twenty-six years. Where could I go now?... My wife is dead, and my children have forgotten me. I have nowhere to go..."

Makar Semyonovich did not rise, but beat his head on the floor. "Ivan Dmitrich, forgive me!" he cried. "When they flogged(鞭打) me with the knot, it was not so hard to bear as it is to see you now... yet you had pity on me and did not tell. Forgive me, devil that I am!" And he began to sob.

When Aksionov heard him sobbing, he too, began to weep. "I will forgive you!" he said. "Maybe I am a hundred times worse than you." And at these words his heart grew light, and the longing for home left him. He no longer had any desire to leave the prison, but only hoped for his last hour to come.

In spite of what Aksionov had said, Makar Semyonovich confessed his guilt. But when the order for his release came, Aksionov was already dead.