As the population of the planet increases, so does the number of homes, business, parking lots, schools, airports and roadways. All these structures use electricity and need to be lighted. Humans demand light. They want their homes more comfortable and they want their streets safe. The problem is that researchers are finding that all the light is having a negative effect on humans and wildlife as well.

    Less than 10 years ago I drove to a thinly populated section of my own, lay down in the middle of the road and watched an attractive meteor shower(流星雨). If I did that today, I wouldn't be able to see the meteor shower.

    Nowadays scientists are finding light pollution can be almost as bad as carbon dioxide （二氧化碳）pollution. One of the saddest parts of light pollution is that most of it is unnecessary and most of the outdoor light that we use is wasted. One only needs to look at a row of street lights to see how much of the lights shines upwards and lights the sky: a total waste of electricity.

    Additionally, the production of electricity creates pollution by releasing greenhouse gases. This affects the air we breathe and our quality of life.

    Scientists are also studying the effects of light pollution on wildlife. Thousands of birds die each year when they crash into highly lighted buildings, as they become puzzled by the light. It has been long known that tiny baby sea turtles become lost and follow the light on the shore instead of heading towards the sea.

    Fortunately, light pollution is one of the easiest sources of pollution that can be corrected without a negative effect. Following some guidelines and a little searching on Google can give you many ideas on how to reduce your contribution to light pollution.

    Some people think if you are happy, you are blind to reality. But when we research it, happiness actually raises every single business and educational outcome for the brain. How did we miss this? Why do we have these social misunderstandings about happiness? Because we assumed you were average. When we study people, scientists are often interested in what the average is.

    Many people think happiness is genetic. That's only half the story, because the average person does not fight their genes. When we stop studying the average and begin researching positive outliers —people who are above average for a positive aspect like optimism or intelligence —a wildly different picture appears. Our daily decisions and habits have a huge impact upon both our levels of happiness and success.

    Scientifically, happiness is a choice. It is a choice about where your single processor brain will devote its limited resources as you process the world. If you scan for the negative first, your brain really has no resources left over to see the things you are grateful for or the meaning embedded(嵌入) in your work. But if you scan the world for the positive, you start to acquire an amazing advantage.

    I wrote the cover story for the Harvard Business Review magazine on “Happiness Leads to Profits.” Based on my article called “Positive Intelligence” and my research in The Happiness Advantage, I summarized our researched conclusion: the single greatest advantage in the modern economy is a happy and busy workforce.

    A decade of research in the business world proves that happiness raises nearly every business and educational outcome: increasing sales by 37%, productivity by 31%, and accuracy on tasks by 19%, as well as a number of health and quality-of-life improvements.

    James Gross, a psychology professor at Stanford University, has a 13-year-old daughter who loves math and science. “It hasn't occurred to her yet that's unusual,” he says. “But I know in the next couple of years, it will.”

    She's already being pulled out of class to do advanced things with a couple of other kids, who are guys. And as someone who studies human emotion for a procession, Gross says, “I know as time goes on, she will feel increasingly lonely as a girl who's interested in math and science, and be at risk of narrowing her choices in life before finding out how far she could have gone.''

    Gross' concern clearly shows what has been a touchy subject in the world of science for a long time: Why are there still so few women in science, and how might that affect what we learn from research?

    Women now make up half the national workforce, earn more college and graduate degrees than men, and by some estimates represent the largest single economic force in the world. Yet the gender gap in science persists, to a greater degree than in other professions, particularly in high-end, math-intensive fields such as computer science and engineering.

    According to US Census Bureau statistics, women in fields commonly referred to as STEM (science, technology, engineering, mathematics) made up 7 percent of that workforce in 1970, a figure that had jumped to 23 percent by 1990. But the rise essentially stopped there. Two decades later, in 2011, women made up 26 percent of the science workforce.

    I travel a lot, and I find out different "styles" of directions every time I ask "How can I get to the post office?"

    Foreign tourists are often confused in Japan because most streets there don't have names; in Japan, people use landmarks in their directions instead of street names. For example, the Japanese will say to travelers, "Go straight down to the corner. Turn left at the big hotel and go past a fruit market. The post office is across from the bus stop."

    In the countryside of the American Midwest, there are not usually many landmarks. There are no mountains, so the land is very flat; in many places there are no towns or buildings within miles. Instead of landmarks, people will tell you directions and distances. In Kansas or Iowa, for example, people will say, "Go north two miles. Turn east, and then go another mile."

    People in Los Angeles, California, have no idea of distance on the map; they measure distance in time, not miles. "How far away is the post office?" you ask. "Oh," they answer, "it's about five minutes from here." You say, "Yes, but how many miles away is it?" They don't know.

    It's true that a person doesn't know the answer to your question sometimes. What happens in such a situation? A New Yorker might say, 'Sorry, I have no idea." But in Yucatan, Mexico, no one answers "I don't know." People in Yucatan believe that "I don't know" is impolite, they usually give an answer, often a wrong one. A tourist can get very, very lost in Yucatan!

The Alexander technique

    Until earlier this year, I didn't know anything about the Alexander technique—and saw no reason to think I should. One day, the backache I regularly suffered was more painful. I was brought up to think that the preferred way of dealing with aches is to do nothing and hope they'll go away, but I eventually went to the doctor. After examining me, he said, "You actually have bad posture (姿势). Go off and learn the Alexander technique." Three months later I could walk straighter and sit better.

    The Alexander technique is a way of learning how you can get rid of harmful tension in your body. The teaching focuses on the neck, head and back. It trains you to use your body less severely and carry out the movements that we do all the time with less effort. There is little effort in the lessons themselves, which sets apart the Alexander technique from yoga or pilates, which are exercise-based. A typical lesson involves standing in front of a chair and learning to sit and stand with minimum effort. You spend some time lying on a bench with your knees bent to straighten the spine (脊椎) and relax your body while the teacher moves your arms and legs to train you to move them correctly.

    The technique helps to break the bad habits accumulated over years. Try folding your arms the opposite way to normal. This is an example of a habit the body has formed which can be hard to break. Many of us carry our heads too far back. The head weighs four to six kilos, so any inappropriate posture can cause problems for the body. The technique teaches you to let go of the muscles holding the head back, allowing it to go back to its natural place on the top of our spines.

    So who was Alexander and how did he come up with the technique? Frederick Alexander, an Australian actor born in 1869, found in his youth that he had vocal (声音的) problems during performances. He analyzed himself and realized his posture was bad. He worked on improving it, with excellent results. He brought his technique to London and opened a teacher-training school, which is still successful today.

    So if you're walking along the road one day with shoulders bent forward, feeling weighed down by your troubles, give a thought to the Alexander technique. It will help you walk tall again.

    In early November of 1942, my geology (地质学)class was supposed to go on a field trip to see the mica mine (云母矿). Although it rained, everyone showed up on time. I was the only girl in the class. We all fit into two cars.

    Near Deary, Mr. Tier, our teacher, went into a store to ask about the direction, while townsmen looked at us with curiosity. On the store owner's advice, we drove out into the hills for a few miles. Then we left the cars. We were afraid they would get stuck in the mud.

    Eventually, we located the mine near the top of the mountain. There was a very small hole, running about two or three hundred feet into the mountainside. The passage (通道) was so narrow that we could touch both sides with our hands, and not tall enough to allow us to stand up straight. The first boy held the torch; we took hold of the backs of each other's coats, in a line, and followed him in, ducking our heads. After getting in, we were disappointed because it was not the mine our teacher was looking for.

    The rain was coming down hard as we started back to the cars to go home. Back at Deary, we went into a drugstore and stood around its big heating stove to dry out. The clerk was a middle­aged lady. Seeing our entirely wet hair and clothes, she handed each of us a cup of hot water immediately and asked if there was anything wrong with any of us.

    Hiking eight miles in the rain had not reduced our interest at all. We all felt we had had a wonderful time, even if we didn't find the mine.