Dr. Sasaki knew the first-night effect probably has something to do with how humans evolved.

    The puzzle was what benefit would be gained from it when performance might be affected the following day. She also knew from previous work conducted on birds and dolphins that these animals put half of their brains to sleep at a time so that they can rest while remaining alert enough to avoid predators (捕食者). This led her to wonder if people might be doing the same thing. To take a closer look, her team studied 35 healthy people as they slept in the unfamiliar environment of the university's Department of Psychological Sciences. The participants each slept in the department for two nights and were carefully monitored with techniques that looked at the activity of their brains. Dr. Sasaki found, as expected, the participants slept less well on their first night than they did on their second, taking more than twice as long to fall asleep and sleeping less overall. During deep sleep, the participants' brains behaved in a similar manner seen in birds and dolphins. On the first night only, the left hemispheres (半球) of their brains did not sleep nearly as deeply as their right hemispheres did.

    Curious if the left hemispheres were indeed remaining awake to process information detected in the surrounding environment, Dr. Sasaki re-ran the experiment while presenting the sleeping participants with a mix of regularly timed beeps (蜂鸣声) of the same tone and irregular beeps of a different tone during the night. She worked out that, if the left hemisphere was staying alert to keep guard in a strange environment, then it would react to the irregular beeps by stirring people from sleep and would ignore the regularly timed ones. This is precisely what she found.

    We have to admit that many cities around the world today are heavily polluted. Careless methods of production and lack of consumer demand for environment friendly products have actually contributed to the pollution problem. One result is that millions of tons of glass, paper, plastic, and metal containers are produced and these are difficult to get rid of.

    However, today, more and more consumers are choosing “green” and demanding that the products they buy should be safe for the environment. Before they take action to buy a product, they ask questions like these “Will this shampoo add damage to the environment?” “Can this metal container be reused or can it only be used once?”

    A recent study showed that two out of five adults now take the environmental safety of a product into account before they buy it. This means that companies must now adjust the way they make and sell their products to make sure that they are “green” that is, friendly to the environment

    Only a few years ago, it was impossible to find green products in supermarkets, but now there are hundreds of them advocating green. In addition, some supermarket products carry labels (标签) to show that the product is green. Some companies have adopted the manufacturing (生产) of clean and safe products as their main selling point and emphasize it in their advertising.

    The concern for a safer and cleaner environment is making companies rethink how they do business. No longer will the public accept the old attitude of “Buy it, use it, throw it away, and forget it.” The public pressure is on, and gradually business is cleaning up its act.

    Adults understand what it feels like to be flooded with objects(物品). Why do we often think that more is more when it comes to kids and their belongings? The good news is that I can help my own kids learn earlier than I did how to live more with less.

    I found the pre-holidays a good time to encourage young children to donate less-used things, and it worked. Because of our efforts, our daughter Georgia did decide to donate a large bag of toys to a little girl whose mother was unable to pay for her holiday due to illness. She chose to sell a few larger objects that were less often used when we promised to put the money into her school fund (基金) (our kindergarten daughter is serious about becoming a doctor).

    For weeks, I've been thinking of bigger, deeper questions: How do we make it a habit for them? And how do we train ourselves to help them live with, need, and use less? Yesterday, I sat with my son, Shepherd, determined to test my own theory on this. I decided to play with him with only one toy for as long as it would keep his interest. I expected that one toy would keep his attention for about five minutes, ten minutes, max. I chose a red rubber ball — simple, universally available. We passed it, he tried to put it in his mouth, he tried bouncing it, rolling it, sitting on it, throwing it. It was totally, completely enough for him. Before I knew it an hour had passed and it was time to move on to lunch.

    We both became absorbed in the simplicity of playing together. He had my full attention and I had his. My little experiment to find joy in a single object worked for both of us.

    When the company was small, Google cared a lot about getting kids from Harvard, Stanford, and MIT. But Laszlo Bock, Google's former Senior Vice President of People Operations, said it was the "wrong" hiring strategy. Experience has taught him that there are exceptional kids at many other places, from state schools in California to those in New York. "What we find is that the best people from places like these are just as good if not better as anybody you can get from any Ivy League school," said Bock, who authored a book titled "Work Rules!"

    So what else does Google not care about:

    Grades: Google's data shows that grades predict performance for the first two years of a career, but do not matter after that.

    Brain-teasers: Gone are interview questions such as: Why are manhole covers (井盖) round? How many golf balls can fit in a school bus? "Our research tells us those questions are a waste of time," Bock said. "They're a really coachable skill. The more you practice, the better you get at it."

    Here's what Google does care about:

    Problem solvers: Your cognitive (认知的) ability, or how well you solve problems.

    Leaders: The idea is not whether you were president of the student body or vice president of a bank, but rather "When you see a problem, do you step in and help solve it?" and then critically, "Are you willing to let somebody else take over, and make room for somebody else? Are you willing to give up power?"

    Googleyness: That's what Google calls its cultural fit. It's not "Are you like us?" Bock said. "We actually look for people who are different, because diversity gives us great ideas."

    "What's most important is that people are intellectually humble, willing to admit when they're wrong, and care about the environment around them ...because we want people who think like owners not employees," Bock said.

    People have grown taller over the last century, with South Korean women shooting up by more than 20cm on average, and Iranian men gaining 16.5cm. A global study looked at the average height of 18-year-olds in 200 countries between 1914 and 2014.

    The results show that while Swedes were the tallest people in the world in 1914, Dutch men have risen from 12th place to claim top spot with an average height of 182.5cm. Latvian women, meanwhile, rose from 28th place in 1914 to become the tallest in the world a century later, with an average height of 169.8cm.

    James Bentham, a co-author of the research from Imperial College, London, says the global trend is likely to be due to improvements in nutrition and healthcare. "An individual's genetics has a big influence on their height, but once you average over whole populations, genetics plays a less key role," he added.

    A little extra height brings a number of advantages, says Elio Riboli of Imperial College. "Being taller is associated with longer life expectancy," he said. "This is largely due to a lower risk of dying of cardiovascular(心血管的)disease among taller people."

    But while height has increased around the world, the trend in many African countries causes concern, says Riboli. While height increased in Uganda and Niger during the early 20th century, the trend has reversed in recent years, with height decreasing among 18-year-olds.

    "One reason for these decreases in height is the economic situation in the 1980s,"said Alexander Moradi of the University of Sussex. The nutritional and health crises that followed the policy of structural adjustment, he says, led to many children and teenagers failing to reach their full potential(潜力)in terms of height.

    Bentham believes the global trend of increasing height has important implications "How tall we are now is strongly influenced by the environment we grew up in," he said. "If we give children the best possible start in life now, they will be healthier and more productive for decades to come."

The quality of your sleep is just as important as the quantity. Getting the right number of hours every night is unlikely to benefit you if you are frequently waking up, if you sleep at wildly different times, or if you sleep shallowly. Here are some tips that help you get quality sleep.

{#blank#}1{#/blank#} You will sleep the most soundly if you go to bed and wake up around the same time every day. {#blank#}2{#/blank#} Work, children, and other demands on your time may determine your rhythm. Many sleepers, especially night owls, may be tempted to sleep in longer on weekends. Try to keep the same wake-up time, even on weekends.

Determine your natural sleep schedule. If you have the freedom to determine your own sleep schedule, do so around the rhythms of your body. {#blank#}3{#/blank#} Notice when you feel sleepy, and when you feel the most awake. To establish a natural sleep rhythm, spend a week or two waking up without an alarm clock. Keep a log with all the times you wake up.

Stay asleep.{#blank#}4{#/blank#}This can be difficult if you are an evening person, if you have children, or if you are a light sleeper. Making arrangements in your bedroom and winding down properly can make a huge difference, but so can prioritizing staying asleep. Tell yourself and tell everyone you live with that you need to stay asleep all night.

Sleep enough. Most adults need to sleep between seven and nine hours a night. Teenagers need eight to10 hours of sleep, and school-aged children need at least 10 hours. Sleeping too little can expose you to higher risks of illness, anxiety, and disease. {#blank#}5{#/blank#}

A. Make lifestyle changes to promote better sleep.

B. Establish a regular bedtime and wake up time.

C. This rhythm helps your body prepare for sleep.

D. Your body has natural waking and sleeping moments.

E. Do everything in your power to avoid waking up at night.

F. Sleeping too much, however, may reduce the quality of your sleep.

G. If you haven't fallen asleep after 15 minutes, get up and do a brief, relaxing activity.