Urban swans might be born with a daredevil gene that makes them less fearful of humans, compared with their rural colleagues.

    A study has found swans living in cities tend to be bolder and it is at least partly determined by a gene called DRD4. Birds with this gene could therefore be better adapted to settling in more populated areas, while more timid（胆怯的）swans would escape to less inhabited regions.

    It could help to explain why swans in public parks and on urban rivers have a reputation for being so aggressive towards humans - they are simply not afraid of us.

    Biologists from some universities in Australia, tracked and collected blood samples from black swans living in two wetlands near cities. One group of swans lived in a recreational urban park, while the other occupied a waste-water processing site out of town. The two areas were less than 20 miles apart. Later, from 2011 through 2013, the researchers started systematically scaring the swans at both sites. The researchers approached the birds and calculated how close they could get before they flew away. As expected, they noticed that while rural swans started flying away if a human was closer than 119 meters, the scientists could come as close to urban swans as 39 meters before taking off.

    Analyses of the blood samples, in fact, showed that 83 per cent of the less cautious swans presented the same genetic DRD4 variation（变异)while rural swans have different genetic makeups resulting in more wariness(谨慎，小心）.

The researchers conclude that swans with the bold variation of the gene might choose to live in urban environments, as they tend to be less bothered by human presence.

    A disease called “Panama” is threatening supplies of the world's most popular fruit—banana.Two years ago,the United Nations warned that the "Panama disease" could destroy "much of the world's banana crop."Since then,things have not gotten better.A new outbreak was discovered last year in Australia.The disease started in Asia in the 1990s, and later spread to Africa and the Middle East.

    World health officials worry the disease could travel to Latin America,one of the top banana producers in the world.All this is a big concern because bananas are an important source of income and nutrients for millions of people.They are grown in 135 tropical nations.The United Nations lists bananas as one of the most important foods, along with rice,wheat and corn.

    Randy Ploetz is a professor at the Tropical Research & Educational Center at the University of Florida.Many consider him as America's top banana expert.As he explained,Panama disease affects the Cavendish banana.The Cavendish is one of more than 500 kinds of bananas.But it is the most popular.

    “The industry is waking up to the problem,”Ploetz said.“They are pretty scared.”He was speaking Thursday by telephone from Miami,Florida,where he is among 1,000 people attending the International Banana Congress.The meeting was supposed to take place in Costa Rica,but was moved at the last minute.There were concerns banana growers could spread Panama disease from dirt collected on their shoes,Ploetz said.

    Ploetz said reports that Cavendish banana production could end are not correct.But if the disease spreads to Latin America,it could hurt the world's economy along with food supplies for millions of people.Still,he said there is reason for hope.Scientists in Australia are working on a genetically engineered banana that might not be at risk of getting Panama disease.

    One day an old woman was traveling alone in the mountains. Suddenly she saw something shining in the stream. When she came close, she found it was a precious （珍贵的） stone. She put the stone into her bag and went on with her trip.

    The next day the old woman met a young man, who was also a traveler in the mountains. The young man looked very hungry, so the old woman opened her bag to share her food. The hungry traveler saw the precious stone and asked carefully, “The stone is beautiful. Would you like to give it to me?”

    “Sure. Why not?” the woman said, and handed the stone to him.

    The young man left happily with the stone. He knew it was worth enough to give him security for a lifetime. But a few days later he came back to return the stone to the woman.

    “I've been thinking,” he said. “I know how valuable the stone is, but I give it back and hope that you can give me something even more precious. Give me what you have within your bag.”

    The woman opened her bag. It was almost empty. She looked at the young man and smiled, “I have nothing special in my bag, but I do have something precious — the joy of giving!”

    The young man felt ashamed and left silently.

    Our lifestyles today are very busy. We have family, school, sports, entertainment and social activities to fit into a time that seems never enough. We need to be healthy to meet the demands of daily life. But what does it mean to have a healthy lifestyle?

    To have a healthy lifestyle, we need to: eat different kinds of healthy food most of the time do exercise often have time to relax get enough sleep to give our bodies time to grow healthy and strong

    Read about a normal day in the lives of two children.

    Abbey gets up at 7:00 am, feeds the dog, and has cereal and a glass of juice for breakfast. She walks to school with her friend, Julia. She has a bag of chips for a morning snack, drinks water, and has a chicken and lettuce sandwich with a banana for lunch. She likes to play soccer with her friends at lunch and morning break time. She walks home with Julia, has some crackers with cheese and juice for afternoon snack and plays with the dog for a while. She plays computer games for an hour or two before dinner, then has a shower and does her homework. She watches her favorite television show for an hour, then usually goes to bed at about 9:30 pm.

    Carl gets up at 8:30 am and has two pieces of bread with jam and a glass of milk for breakfast. His mother drives him to school on her way to work. He eats cookies with juice for morning snack and a pot pie ordered from the school lunch room with juice for lunch. He likes to play card games with his friends at lunchtime and climb the fixed equipment at morning break time. He catches the bus home, has a cereal bar and a can of soda for afternoon snack, then watches some television. He has a shower before dinner, then plays the computer for an hour or two. He goes to bed at about 10:30 pm.

    Augustus Saint-Gaudens and his family immigrated to New York, America, from Dublin, Ireland, in 1848 when he was just six months old. As he grew up, Augustus liked racing his friends around the block, buying candies at the store, especially drawing—drawing pictures of the shoemakers at his father's shoe shop. At the age of 13, his father told him it was time to go to work. Augustus replied, "I should like it if I could do something which would help me to be an artist." He began as an apprentice to a cameo cutter out of stone and shell, and carved cameos of people, lions, and even the head of Hercules from Greek mythology, when the Civil War had just begun.

    At 19, with his earnings and his parents' support, he travelled to Paris and Rome for further training and artistic study. Before he left, he drew a portrait of his mother in pencil and sculpted a small bust(半身像) of his father out of clay. Then, 22-year-old Augustus opened an art studio in Rome and worked on his first life-sized sculpture, called Hiawatha. An art patron was impressed with this sculpture and promised to help Augustus "until your genius and labors shall have met with the reward to which I feel they are entitled".

    In 1876, Augustus was chosen to design a monument to the Civil War hero Admiral David Farragut of the U. S. Navy. Completed five years later, when he was 33, his first major sculpture for the U. S. was unveiled at Madison Square in New York City, the sculptor's boyhood home. One art critic called it "the best monument of the kind the city has to show". Then the giant Standing Lincoln in Lincoln Park, Chicago in a setting by architect White, 1884-1887, was considered the finest portrait statue in the U. S.

    However, in 1900, aged 52, his doctors told him he had cancer. Even though he was often ill, he continued to work at his home and studio in Cornish, New Hampshire.

    In 1905, President Theodore Roosevelt requested that Augustus redesign American coins—to convey the strength of the nation. Augustus made lifelike pencil sketches of his coin designs. Yet, Augustus died in August 1907, two months before his l0-dollar and 20-dollar gold coins were issued. Augustus Saint-Gaudens had fulfilled his dream-and more! He was one of the greatest American sculptors not only of his day but also of all time.

    "Dad," I say one day, "Let's take a trip. Why don't you fly and meet me?"

    As a manager from IBM, my father's job filled his day, his thought, his life. While he woke up and took a warm shower, I had fun under the Eiffel Tower. While he tied a tie and put on the same Swiss watch, I rowed a boat across Lake of the Ozarks.

    My father sees me travelling without a purpose, nothing to show for my 33 years but a passport full of funny stamps. He wants me to settle down (安定下来), but now I want him to explore the world.

    He agrees and we meet four weeks later in Rapid City.

    "What is our first stop?" asks my father.

    "What time is it?"

    "Still don't have a watch?"

    Less than an hour away is Mount Rushmore. As he looks up at sculptures of the four Presidents in granite(花岗岩), his mouth and eyes open slowly, like those of little boy.

    "Amazing," he says, "How was this done?"

    A film in the information center shows sculptor(雕塑家) Gutzon Borglum devoted 14 years to the sculptures.

    We look up and I ask myself, "Can I devote my life to anything?"

    No directions, no purpose. I always used to hear those words in my father's voice. Now I hear them in my own.

    The next day we're at Yellowstone National Park, where we have a picnic.

"Did you ever travel with your dad?" I ask.

    "Only once," he says. "I never spoke much with my father. We loved each other—but never said it. Whatever he could give me, he gave."

    The last sentence—it's probably the same thing I will say about my father. And what I want my child to say about me.

    In Glacier National Park, my father says, "I've never seen water so blue." I have, in several places of the world. I can keep traveling. I realize— and maybe a fixed job won't be as boring as I think.

    Weeks after our trip, I call my father. "The photos from the trip are wonderful," he says. "We have got to take another trip like that sometime." I tell him I've decided to settle down and find a fixed job, and I'm wearing a watch.