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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    Age has never been a problem for 16-year-old Thessalonika Arzu-Embry. After all, she's already got her master's degree.

    The North Chicago-area teen started homeschooling at the age of 4. She began having an influence on others soon after. When she was 6 years old, she was an inspirational speaker at an organization called Tabitha House Community Service, a shelter for people who were forced to leave their homes due to the situations such as earthquake, flood and other natural disasters.

    At the age of 11, she graduated from high school and then earned her bachelor's degree in psychology in 2013. She completed those classes online as she was traveling for church events and leadership meetings.

    She doesn't stop there, though. The teen plans to focus on aviation psychology（航空心理学） for her further study, a decision inspired by her father who is a pilot. She grew up around airplanes and took fights all the time. Her goal is to use it to determine whether pilots are dealing with problems that could have deadly results once the plane takes off -- a topic that has been in the news lately. For her, it's a mix of two of her interests.

    In her free time, Thessalonika enjoys playing tennis, swimming and being active in her youth group at church. She also has three self-published books, which are on her site. Jump the Education Barrier is written to help students finish college, and in the future aims to help business owners with trends. Her third book The Genius Race, has a wider appeal. It is designed to help people to be geniuses in various areas of life.

How Room Designs Affect Our Work and Feelings

    Architects have long had the feeling that the places we live in can affect our thoughts, feelings and behaviors. But now scientists are giving this feeling an empirical（经验的，实证的） basis. They are discovering how to design spaces that promote creativity, keep people focused and lead to relaxation.

    Researches show that aspects of the physical environment can influence creativity. In 2007, Joan Meyers-Levy at the University of Minnesota, reported that the height of a room's ceiling affects how people think. Her research indicates that higher ceilings encourage people to think more freely, which may lead them to make more abstract connections. Low ceilings, on the other hand, may inspire a more detailed outlook.

    In additions to ceiling height, the view afforded by a building may influence an occupant's ability to concentrate. Nancy Wells and her colleagues at Cornell University found in their study that kids who experienced the greatest increase in greenness as a result of a family move made the most gains on a standard test of attention.

    Using nature to improve focus of attention ought to pay off  academically, and it seems to, according to a study led by C. Kenneth Tanner, head of the School Design & Planning Laboratory at the University of Georgia. Tanner and his team found that students in classrooms with unblocked views of at least 50 feet outside the window had higher scores on tests of vocabulary, language arts and maths than did students whose classrooms primarily overlooked roads and parking lots.

    Recent study on room lighting design suggests than dim（暗淡的） light helps people to loosen up. If that is true generally, keeping the light low during dinner or at parties could increase relaxation. Researchers of Harvard Medical School also discovered that furniture with rounded edges could help visitors relax.

    So far scientists have focused mainly on public buildings. "We have a very limited number of studies, so we're almost looking at the problem through a straw（吸管）," architect David Allison says. "How do you take answers to very specific questions and make broad, generalized use of them? That's what we're all struggling with."

    Maybe ten-year-old Elizabeth put it best when she said to her father. “But, Dad, you can't be healthy if you're dead.”

    Dad, in a hurry to get home before dark so he could go for a run, had forgotten to wear his safety belt — a mistake 11.5% of the US population make every day, according to a survey in 2015.

    The percentage doesn't seem so bad, but the big question is why still so many people ignore it when every day there are reports about car accidents and casualties (a death toll of 37461 in 2016).

    There have been many myths about safety belts ever since their first appearance in cars some forty years ago. The following are three of the most common.

    Myth Number One: It's best to be “thrown clear”of a serious accident.

    Truth: Sorry, but any accident serious enough to “throw you clear”is also going to be serious enough to give you a very bad landing. And chances are you'll have traveled through a windshield (挡风玻璃) or door to do it. Studies show that chances of dying after a car accident are twenty-five times greater in cases where people are “thrown clear.”

    Myth Number Two: Safety belts “trap” people in cars that are burning or sinking in water.

    Truth: Sorry again. but studies show that people knocked unconscious (昏迷) due to not wearing safety belts have a greater chance of dying in these accidents People wearing safety belts are usually protected to the point of having a clear head to free themselves from such dangerous situations, not to be trapped in them.

    Myth Number Three: Safety belts aren't needed at speeds of less than 30 miles an hour (mph).

    Truth: When two cars traveling at 30 mpb hit each other, an unbelted driver would meet the windshield with a force equal to diving headfirst into the ground from a height of 10 meters.

    Panama City, Panama

    For beach vacations that get you out of town and invite you and your family to dive into culture, consider a trip to Panama City. Here, you will enjoy beaches and city exploring. Book your stay at the Westin Playa Bonita, where you can book a room starting at $222 a night. There are various programs, including beach Olympics, stargazing (天体观察）and Spanish lessons.

    Jupiter, Florida

    This place offers you quality time you can spend with your loved ones. Book your stay at Jupiter Beach Resort & Spa, with rates for a family of four starting at $207 a night. Here, you can shoot baskets at the basketball courts, take a dip in the pool or teach your children beach yoga.

    San Diego, California

    The West Coast is a great spot for cheap beach vacations, so tell your family to pack their bags for a visit to San Diego. A cheap $10 Uber ride from the airport will have you pulling up the Kona Kai Resort & Spa. Here, a family of four can stay in a Deluxe Guest Room starting at $159 per night. Your kids can practice cannonballs at the pool after a visit to the world-famous San Diego Zoo.

    Kihei Maui, Hawaii

    For West Coasters who are growing bored with their backyard, fly to the islands of Hawaii. Stay at the Aston at the Maui Banyan, with a charge of $179 a night for a family of four. Here, you'll witness some of the best sunsets of your life while your kids splash (戏水）in the Pacific, And if you're set on cooking a fancy meal, you'll enjoy suites that come with a full kitchen.

There are two types of people in the world. Although they have equal degree of health and wealth and other comforts of life, one becomes happy and the other becomes unhappy. This arises from the different ways in which they consider things, people, events and the resulting effects.

    People who are to be happy fix their attention on the convenience of things: the pleasant parts of conversation, the well-prepared dishes, the goodness of the wine and the fine weather. They enjoy all the cheerful things. Those who are to be unhappy think and speak only of the opposite things. Therefore, they are continually dissatisfied. By their remarks, they sour the pleasure of society, hurt many people, and make themselves disagreeable everywhere. If this turn of mind was founded in nature, such unhappy people would be more pitiful. The intention of criticising and being disliked is perhaps taken up by imitation. It grows into a habit, unknown to its possessors. The habit may be strong, but it may be cured when those who have it realise its bad effects on their interests and tastes. I hope this little warning may be of service to them, and help them change this habit.

    Although in fact it is chiefly an act of imagination, it has serious results in life since it brings on deep sorrow and bad luck. Those people hurt many others; nobody loves them, and no one treats them with more than the most common politeness and respect. This frequently puts them in a bad temper and draws them into arguments. If they aim at getting some advantages in social position or fortune, nobody wishes them success. Nor will anyone start a step or speak a word to favour their hopes. If they bring public objections to themselves, no one will defend or excuse them, and many will join in to criticise their wrongdoings. They should change this bad habit and be pleased with what is pleasing, without worrying needlessly about themselves and others. If they do not, it will be good for others to avoid any contact with them. Otherwise, it can be disagreeable and sometimes very inconvenient, especially when one becomes mixed up in their quarrels.