There are lots of insects that farmers hate. But there also are some they like. They protect crops against damage from other insects. A good example is the lady beetle, which is also known as the ladybug(瓢虫)．

    Lady beetles are a natural control for aphids(蚜虫). Lady beetles are red, orange or black. They often have black spots, though some have light colored spots. Different kinds of lady beetles have different numbers of spots. There are lady beetles with four, five, seven and fourteen spots.

    Many of the well-known kinds of lady beetles come from Asia or Europe. They now are common throughout the United States.

    American scientists imported one kind of lady beetle, the multicolored Asian lady beetle, as early as 1916. They released them as an attempt to control some kinds of insects. Over the years, the beetle has become established, possibly helped by some that arrived with imported plants on ships.

    Experts say over 450 kinds of lady beetles are found in North America. Some are native to the area. Others have been brought from other places. Almost all are helpful to farmers.

    The Asian lady beetles now in the United States probably came from Japan. The Asian lady beetle eats aphids that damage crops like soybeans, fruits and berries.

    In the southern United States, Asian lady beetles have reduced the need for farmers to use reskilling poisons on pecan trees. This popular tree nut suffers from aphids and other pests that the lady beetles eat.

    But some people say the Asian lady beetle has itself become a pest. They worry that the lady beetles may eat their late autumn fruit crops.

    Experts say Asian lady beetles may appear in large numbers in some years. But they say the insects are too helpful to be considered as pests.

    Climbing Without Ropes

    The popular image of the mountain climber is of a person carefully climbing a steep cliff with a network of safety ropes, but it is not the only kind. Many climbers now enjoy bouldering. It's more accessible and better for the environment.

    Here is an example of a climber addressing a bouldering problem.

    Figure 1: The climber has two routes she could take, one to the left and one to the right. The left one appears easier because it has a jug within easy reach, but look what happens if she chooses that direction. She gets stuck on the rock and has to go back down. Sometimes that is even more difficult than going up.

    Figure 2: The climber takes the one to the right this time. Using a foothold and placing her right hand in a crimp, she is able to lift herself up and locate other handholds. After only a few moves, she is able to throw her leg over the top of the boulder and pull herself up.

    Human began farming around 12,000 years ago, and only in the past 50 years have scientists realized we're not the only species to research into agriculture. A new study has revealed that a small Fijian ant species beat us to becoming the first farmers by almost three millions years.

    The ants have been observed carefully sowing seeds, fertilizing (施肥) them, and waiting for them to grow into plants which bear tasty fruit. What led to the formation of this relationship remains a mystery to scientists. But it puts the ants millions of years ahead of the first human societies to use farming techniques.

    The newly discovered relationship is unique to the animal kingdom. Researchers say they have already watched ants spread seeds, and ants feed plants, but they never had a case where they farm a plant they can't live without. The ants rely on the plants for shelter and food, while the plants need the ants to sow and spread their seeds.

    The find puts the ants millions of years ahead of the first human societies to use farming techniques, who began using agriculture around 12,000 years ago.

    As the plants grow under the care of the ants, the plants to keep further growth. Once the plant is big enough, its hollow chambers provide shelter for the ants. It had previously been spotted that the ants like to live in these small chambers, but the Munich researchers have uncovered the true nature of the relationship that ants sow and take care of the plants to grow themselves a new home.

    The ants will eat the fruit of the plant and harvest their seeds for further projects.

While many other examples of mutually (相互地) beneficial relationships between ants and plants exist, the discovery marks the only case in which both parties other for are totally dependent on each other survival.

    A new study shows students who write notes by hand during lectures perform better on exams than those who use laptops.

    Students are increasingly using laptops for note-taking because of speed and legibility(清晰度).But the research has found laptop users are less able to remember and apply the concepts they have been taught.

    Researchers performed experiments that aimed to find out whether using a laptop increased the tendency to make notes "mindlessly" by taking down word for word what the professors said

    In the first experiment, students were given either a laptop or pen and paper .They listened to the same lectures and were told to use their usual note-taking skills. Thirty minutes after the talk, they were examined on their ability to remember facts and on how well they understood concepts.

    The researchers found that laptop users took twice as many notes as those who wrote by hand. However, the typists performed worse at remembering and applying the concepts. Both groups scored similarly when it came to memorizing facts.

    The researchers' report said, "While more notes are beneficial, if the notes are taken mindlessly, as is more likely the case on a laptop, the benefit disappears."

    In another experiment aimed at testing long-term memory, students took notes as before but were tested a week after the lecture. This time, the students who wrote notes by hand performed significantly better on the exam.

    These two experiments suggest that handwritten notes are not only better for immediate learning and understanding, but that they also lead to superior revision in the future.

    One of the most outspoken supporters that I know of women and girls is actually a man. As co­founder of the ONE Campaign, my friend Bono spends a lot of time speaking out against global poverty (贫困). Together, we're working to get out a simple, powerful message: poverty is sexist.

    Women and girls are more likely to be in poverty, less likely to get an education and more likely to suffer bad health. And when they are born into poverty, it is much more difficult for them to lift themselves and their families out of it.

    Why? One reason is that breaking out of poverty takes time­and that is a resource women around the world are short on. On average, women spend about twice as much time as men in doing the unpaid work that makes life possible for everyone, like cooking, washing, cleaning, shopping and caring. In developing countries, the gap is even much bigger. As a result, women have no time to finish their education, learn new skills, open a business, develop personal relationships or even go to the doctor. They dream of creating a better future for their children, but they can not spare the hours to put those dreams that they have into action.

    The fact that the potential of so many women and girls is going unrealized is a sad thing­but it is also an opportunity for us. We need to recognize, reduce and redistribute the burden of work that is holding them back. Because if women have time to invest (投资) in themselves and their ideas, they could transform the world.

    Fred Rogers was a curious man, six feet tall and without pretense (虚伪). He liked to pray, to play the piano, to swim, and to write, and he somehow lived in a different world than I did. We became friends for some 20 years, and I made lifelong friends with his wife, Joanne. I remember thinking that it seemed as if Fred had access to another realm (领域) like the way pigeons have some special magnetic compass that helps them find home.

    Fred died in 2003, somewhat quickly, of stomach cancer. He was 74. "Just don't make Fred into a saint (圣人)," That has become Joanne's refrain (叠句). 91 now, still full of energy, she lives alone in the same roomy apartment, in the university section of Pittsburgh, that she and Fred moved into after they raised their two boys. Throughout her 50-year marriage to Fred, she wasn't the type to hang out on the set or attend production meetings. That was Fred's thing. He had his career, and she had hers as a concert pianist. For decades she toured the country with her college classmate, Jeannine Morrison, as a piano duo; they didn't retire the performance until 2008.

    "If you make him out to be a saint, people might not know how hard he worked," Joanne said. Disciplined, focused; a perfectionist — an artist. That was the Fred she and the cast and crew knew. "I think people think of Fred as a child-development expert," David Newell, the actor who played Mr. "Speedy Delivery" McFeely, told me recently. "As a moral example maybe. But as an artist? I don't think they think of that." that was the Fred I came to know. Creating, the creative impulse (冲动), and the creative process were our common interests. He wrote or co-wrote all the scripts for the program — all 33 years of it. He wrote the melodies. He wrote the lyrics. He structured a week of programming around a single theme, many of them difficult topics, like war, divorce, or death.

    I don't know that he cared whether people saw him as an artist. He seemed more intent (急切的) that people not see him at all. The focus was always on you. Or children. Or the tiny things. It was hard to see Fred.

    I like you just the way you are. One day he told me where that core message came from. His grandfather, Fred Brooks McFeely, who like the rest of the Rogers family lived in Latrobe, Pennsylvania, about 40 miles east of Pittsburgh. "He was a character," he said. "Oh, a lot of me came from him."

    His grandfather represented a life of risk and adventure, the very things Fred's boyhood lacked. He was a lonely kid, an only child until he was 11, when his sister came. He was bullied. Here comes Fat Freddie! He was sickly. He had asthma. He was not allowed to play outside by himself. He spent much of his childhood in his bedroom.

    He had music, and he had puppets to keep himself amused. He didn't need much. He was expected to fill his father's shoes, become his business partner at the brick company. "My dad was pretty much Mr. Latrobe," he told me. "He worked hard to accomplish all that he did, and I've always felt that that was way beyond me. And yet I'm so grateful that he didn't push me to do the kinds of things that he did or to become a miniature (缩小的) version of him. It certainly would have been miniature."

    Fred wanted to be like his grandfather. "He taught me all kinds of really neat stuff!" he told me. "I remember one day my grandmother and my mother were telling me to get down, or not to climb, and my grandfather said: ‘Let the kid climb on the wall! He's got to learn to do things for himself!' I heard that. I will never forget that. What a support that was. He had a lot of stone walls on his place." "I think it was when I was leaving one time to go home after our time together," Fred told me, "that my grandfather said to me: ‘You know, you made this day a really special day. Just by being yourself. There's only one person in the world like you. And I happen to like you just the way you are."