Hummingbirds(蜂鸟) are one of nature's most energetic fliers and the only birds to hover(盘旋) in the air by relying on their strength alone.

    Now scientists have found that it is the ratio(比值) of the bird's wing length to its width that makes them so efficient. The discovery is helping experts compete with 42 million years of natural selection to build helicopters that are increasingly efficient.

    David Lentink, an assistant professor at Stanford University in California, tested wings from 12 different species of hummingbirds, which he sourced from museums. He placed them on a machine used to test the aerodynamics(气力学) of the helicopter blades(桨叶). Professor Lentink's team used the same machine to test the blades from an advanced micro-helicopter used by the UK's army. They found that the micro-helicopter's blades are as efficient at hovering as the average hummingbirds.

    But while the micro-helicopter's blades kept pace with the average hummingbird wings, they could not keep up with the most efficient hummingbird's wing. The wings of Anna's hummingbird were found to be about 27 percent more efficient than the man-made micro- helicopter's blades.

    While Professor Lentink wasn't surprised at nature's superiority, he said that helicopter blades have come a long way. “The technology is at the level of an average hummingbird,” he said. “A helicopter is really the most efficient hovering device that we can build. The best hummingbirds are still better, but I think it's amazing that we're getting closer. It's not easy to match their performance, but if we build better wings with better shapes, we might match hummingbirds.”

    Professor Lentink said that we don't know how hummingbirds maintain their flight in a strong wind, how they navigate(确定方向) through branches, or how they change direction so quickly. He thinks that great steps could be made by studying wing aspect ratios-the ratio of wing length to wing width. Understanding these abilities and characteristics could be a benefit for robotics and will be the focus of future experiments.

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    We all fail,all the time.We might miss a call with a client because of an emergency work meeting,or miss that meeting because another project has suddenly become urgent.And then we (or our families) get sick,and we have to shift priorities around again.

    These unsystematic failures are benign,though.They reflect that all of us have limited resources.There simply is not enough time,energy,or money,to do everything you want to do all the time.Part of being a responsible adult is learning to make trade offs: balancing your conflicting goals and trying to get as much done as you can in the time you have.

    The thing you really need to watch out for is the systematic failure.The systematic failure happens when there's a particular goal you want to achieve,but never get to.The causes of systematic failures usually boil down to some combination of these three factors:

    1).Short-term pressures versus long-term goals.Most of us prefer to achieve pressing short-term goals rather than put time into long-term projects.Lots of research suggests that our brains are wired to prefer tasks that pay off in the short term rather than those whose benefit is long-term.The people who do manage to accomplish their long-term goals create regular space to make progress on them.

    2)._________Without even realizing it,we often do what is easiest to accomplish rather than what we say is most important.Email is a great example.If you are like most people,you keep your email program open at work all day. Consequently,each new message is an invitation to drop what you are working on to check it.It feels like work and it's much easier than finishing that 100-slide presentation.Simply shutting off email for a few hours a day can remove this source of distraction from the environment.

    3).Working for too long.Many workplaces create pressure to stay at the office for more and more hours,which (paradoxically) creates opportunities for systematic failures.Work is not an iron man competition where the last person there wins.Most people have an optimal（最佳的）number of hours they can work each day.For example,I can be productive at work for about 8-9 hours a day.If I spend any more time at work than that,then at some point,I start doing "fake work."

    The next time you run into trouble,assess whether it's an unsystematic failure or a systematic one.When you notice a systematic failure in your life,you need to make a change in your behavior.If you don't make a change,you will continue to fail.

    Finally,if you experience a lot of unsystematic failures,it might be worth rethinking the number of tasks you are taking on.Perhaps you need to offload some responsibilities onto someone else,before you start experiencing more systematic failures.

    This day three foreign gentlemen came to a bus stop in England and waited. About five minutes later, the bus they wanted came along. They were just going to get on when suddenly there was a loud noise behind them. People rushed onto the bus and tried to push them out of the way. Someone shouted at them. The bus conductor came rushing down the stairs to see what the trouble was about. The three foreigners seemed all at sea and looked embarrassed. No one had told them about the British custom of lining up for a bus — the first person who arrives at the bus stop is the first person to get on the bus.

    Learning the language of a country isn't enough. If you want to have a pleasant visit, find out as much as possible about the manners and customs of your host country. You will probably be surprised just how different they can be from your own. A visitor to India would do well if he/she knows that people there consider it impolite to use the left hand for passing food at table. The left hand is supposed to be used for washing yourself. Also in India, you might see a man shaking his head to show that he doesn't agree. But in many parts of India a shake of the head means agreement. Nodding your head when you are given a drink in Bulgaria will probably leave you thirsty.

    At a meal in countries on the Arabic Peninsula, you will find that your glass is repeatedly refilled as soon as you drink up. If you think that you have had enough, you should take the cup or glass in your hand and give it a little shake from side to side or place your hand over the top.

    In Europe it is quite usual to cross your legs when you are sitting talking to someone even at an important meeting. Doing this in Thailand, however, could cause trouble. Also, you should try to avoid touching the head of an adult — it's just not done in Thailand.

    "Have a nice day！" may be a pleasant gesture or a meaningless expression. When my friend Maxie says "Have a nice day" with a smile, I know she sincerely cares about what happens to me. I feel loved and safe since another person cares about me and wishes me well.

    "Have a nice day. Next！" This version of the expression is spoken by a salesgirl at the supermarket who is rushing me and my groceries out the door. The words come out in the same tone (腔调) with a fixed procedure. They are spoken at me, not to me. Obviously, the concern for my day and everyone else's is the management's attempt to increase business.

    The expression is one of those behaviors that help people get along with each other. Sometimes it indicates the end of a meeting. As soon as you hear it, you know the meeting is at an end. Sometimes the expression saves us when we don't know what to say. "Oh, you just had a tooth out? I'm terribly sorry, but have a nice day. "

    The expression can be pleasant. If a stranger says "Have a nice day" to you, you may find it heart­warming because someone you don't know has tried to be nice to you.

    Although the use of the expression is an insincere, meaningless social custom at times, there is nothing wrong with the sentence except that it is a little uninteresting. The salesgirl, the waitress, the teacher, and all the countless others who speak it without thinking may not really care about my day. But in a strange and comfortable way, it's nice to know they care enough to pretend they care when they really don't care all that much. While the expression may not often be sincere, it is always spoken. The point is that people say it all the time when they like.

Discovering the beauty of the science and maths that shape our everyday lives, an experience in Wonderlab will fuel your imagination and inspire you to see the world around you in new and exciting ways. Come and enjoy yourself!

What to see

Spread across seven different zones, there're loads of opportunities to get hands on with real scientific phenomena. Observe live experiments at our Chemistry Bar, see lightning strike before your eyes, play with forces on giant slides or travel through space under a canopy (苍穹)of stars. You can also take part in explosive science demonstrations led by our talented team of explainers. With 50 mind-blowing wonders of science to enjoy, Wonderlab is an experience unlike any other. Besides, a selection of shows will be performed daily in Wonderlab's beautiful new show space. They are free of charge and last 20 minutes.

Tickets

♦ Day pass:  £ 6 per person.

This ticket gives you day-long access to Wonderlab, perfect whether you're planning a special trip to the Museum or simply passing through London and want to feed your curiosity.

♦ Annual pass:  £ 10 per person.

For less than the price of two visits, give yourself a year packed full of wonder, curiosity and breathtaking experiences.

Opening times

Open seven days a week, 10:00 — 18:00 (last entry 17:15). Wonderlab will be closed on December 24，25 and 26 and will be open as usual from December 27.

During school holidays our opening hours are 10:00 — 19:00 (last entry 18:15). Please note that in peak periods (from midday onwards) we are experiencing long queues due to the gallery's popularity.

Study lamps are vital to learning. Finding the best lighting for study is important for everyone. For the sake of maximizing the use of time and energy, and for the very important goal of preserving eyesight, anyone reading for understanding needs not only adequate light, but light that ensures reading with ease. Only when eye strain(疲劳) is not interfering does the learning process move forward.

Desk lamps

You can purchase a large number of stylish desk lamps from lamp stores and online. The products range from precious ones to casual ones, from traditional ones to ultra-modern(超现代的)ones. They feature such desirable additions as dimmer switches and night lights. Some have battery backup in case of power failure and a choice of OttLite bulbs that duplicate natural sunlight.

LED desk lamps

MetaEfficient reviews the most recommended LED desk lamps. These lamps come in many different styles and brand names and are valued for their directed beam of light, lack of heat and exceptional energy efficiency and brilliance. LED study lamps are made in goose neck and swivel(转圈)styles, as well as the more modern Z-bar and the human-like- figure of the Moppel light.

Safest desk lamps

According to Knol, StudyLite is the safest of all desk lamp designs. Not only does it provide LED light, freeing people from UV and IR radiation, but it has been tested to be eye-friendly. It has all the advantages-low cost and long life-of any LED lamps, but it is also equipped with rechargeable battery. Its design and choice of colors make it desirable for more than its efficiency.