A team of engineers at Harvard University has been inspired by Nature to create the first robotic fly. The mechanical fly has become a platform for a series of new high-tech integrated systems. Designed to do what a fly does naturally, the tiny machine is the size of a fat housefly. Its mini wings allow it to stay in the air and perform controlled flight tasks.

    “It's extremely important for us to think about this as a whole system and not just the sum of a bunch of individual components (元件),” said Robert Wood, the Harvard engineering professor who has been working on the robotic fly project for over a decade. A few years ago, his team got the go-ahead to start piecing together the components.“The added difficulty with a project like this is that actually none of those components are off the shelf and so we have to develop them all on our own,” he said.

    They engineered a series of systems to start and drive the robotic fly. “The seemingly simple system which just moves the wings has a number of interdependencies on the individual components, each of which individually has to perform well, but then has to be matched well to everything it's connected to,” said Wood. The flight device was built into a set of power, computation, sensing and control systems. Wood says the success of the project proves that the flying robot with these tiny components can be built and manufactured.

    While this first robotic flyer is linked to a small, off-board power source, the goal is eventually to equip it with a built-in power source, so that it might someday perform data-gathering work at rescue sites, in farmers' fields or on the battlefield. “Basically it should be able to take off, land and fly around,” he said.

    Wood says the design offers a new way to study flight mechanics and control at insect-scale. Yet, the power, sensing and computation technologies on board could have much broader applications. “You can start thinking about using them to answer open scientific questions, you know, to study biology in ways that would be difficult with the animals, but using these robots instead,” he said. “So there are a lot of technologies and open interesting scientific questions that are really what drives us on a day to day basis.”

    When was the last time someone unexpectedly did something nice for you? Not someone you knew, but a total stranger? It's happened to me a few times, but two instances really stand out.

    A few years ago, I was dining in a restaurant with a friend who kept talking about himself completely not aware of the fact that I was sitting there in misery. It wasn't my friend's talks that made me suffer. I was recovering from a broken heart, and just sitting down to dinner reminded me of my last relationship. I could have burst into tears right there at the table.

    When we picked up the check, the waitress said “ Your meal was already paid for .” My friend and I didn't have a clue how it happened. Then I remembered a man I saw out of the corner of my eye. He was dressed in mostly white, sat down at the bar, had a beer, and stayed for maybe ten minutes . The waitress said ,”Yes , the gentleman in white paid for you .” It felt like an angel was saying “I see you , honey. It's going to be okay.”

    Just last year, I was running a half-marathon. With just 1 mile to go, I was out of gas. Runners call it “hitting the wall”. I thought I couldn't move another inch. Out of nowhere, a stranger came up to me and said, “What's your name, sweetie? Jennifer? Okay, Jennifer, let's go! Come on! It's just around the corner! You can do it!” And he ran with me until I picked up my pace. I found him at the finish line to thank him for the encouragement only to learn he wasn't even supposed to be in the race that day.

    I still shake my head when I think of these momentary angels that came to me at my point of need. Do you have any experiences like these?

    Energy goes from one plant or animal to another. A food chain shows how this energy moves. Each time an animal gets eaten, its energy is passed onto the animal that eats it. The food chain is very important because it keeps the balance of nature. If one part of the food chain disappears, it can affect all the other plants and animals. Any threat to the food chain is a threat to the environment's biodiversit(生物多样性). The food chain helps keep animal populations in balance. However, if something happens to increase or decrease one of the links in the food chain, that balance is broken. If one animal becomes endangered, it puts all the animals above it at risk.

    Some of the threats are natural, such as wildfires, hurricanes, tornados, floods and so on. But the biggest threats to the food chain come from you and me. These threats include overhunting, overfishing, logging, farming, development, pollution, etc. The food chain is endangered anywhere humans have had an effect on the natural environment.

    A recent study shows that the overfishing of large sharks is damaging the food chain along the US Atlantic coast. Canadian and American scientists say sharks are being killed in great numbers for their meat and fins(鳍). Now, not enough sharks are around to eat the cownose(牛鼻) ray. The ray's population has increased and they have eaten up the shellfish to the point where it has hurt commercial(商业的) fishing.

    Many of us disturb the natural environment in our own backyards. It's up to us to take care of the environment and try not to disrupt the natural food chain. If we don't act responsibly, animals will start disappearing.

    An old farmer lived on a farm with his young grandson. Each morning Grandpa was up early to read his holy. His grandson wanted to be just like him and tried to imitate him in every way he could.

    One day the grandson asked, "Grandpa! I try to read holy（圣书） just like you but I don't understand it, What good does reading the holy do?"

    The Grandfather quietly turned from putting coal in the stove and replied, "Take this coal basket down to the river and bring me back a basket of water." The boy did as he was told, but all the water leaked out (漏出) before he got back to the house. The grandfather laughed and said, "You'll have to move a little faster next time," and sent him back to the river with the basket to try again. This time the boy ran faster, but again the same took place. He told his grandfather that it was impossible to carry water with a basket.

    The old man said, "You're just not trying hard enough," So the boy again dipped the basket into the river and ran hard, but when he reached his grandfather the basket was again empty, he said, "See Grandpa, it's useless!", "So you think it is useless?" The old man said, "Look at the basket."

    The boy looked at the basket and for the first time realized that the basket was different. It had been changed from a dirty old coal basket into a clean one inside and outside.

    "You might not understand or remember everything, but when you read it, you will be changed, inside and out. That is the work of Krishna in our lives."

    I spend half of my life with my mother and the other half with my father. My father lives with a twenty-pound cat named Tofu. He calls me his favorite daughter. I am an only child.

    My father's apartment is quite different from any other person's living space. Except for my room, there is no furniture. He doesn't like sofas or any comfortable chairs, so he has only a drawing table, a desk and his bed. He spends a lot of time lying on the studio floor. That's how he thinks, he says. Then he does yoga

    He has a big kitchen, and on top of the refrigerator is an old clock he winds every week for good luck. The last time the clock stopped, my father's car was towed(被警察拖走) and some other terrible things happened, so he has become very superstitious (迷信的) . When he goes out of town, he hires someone to feed Tofu and wind the clock so it won't stop.

    The one thing he has plenty of is house rules. You have to take off your shoes when you come in. He won't allow anyone who wears a baseball cap into his house. He says only baseball players should wear baseball caps and only the catchers should wear them backward. Every time I go to stay in his house, he makes up a new rule. "House rule number 579, no television programs with laugh tracks!" he will say. But then be can never remember the numbers, so they change constantly.

The rule that he always enforces is the one that requires me to write a two-page essay anytime I want something. He didn't speak English until he was sixteen, and he had a hard time learning to write it, so he wants me to become a good writer at an early age. This ritual(仪式)started when I asked him if I could have my ears pierced when I was nine. He said it was very cruel and told me I couldn't do it until I was thirty-five. But l kept asking him, and he finally said that if I wrote an essay and I could persuade him in writing why I wanted holes in my ears, maybe he would say okay. I wrote my first essay for my father, and after one month of writing and rewriting, he finally gave me his permission.