You may have heard adults say they are uncomfortable in the morning without a cup of coffee. One reason they may feel that way is that coffee contains caffeine(咖啡因). Caffeine appears naturally in coffee, tea, and cocoa beans, which are used to make chocolate. But now food makers are adding it to many products, from potato chips to water.

    The US government is especially worried about the problem. That's why the Food and Drug Administration (FDA) is studying the health effects of caffeine on young people. Studies show that too much caffeine can make people nervous and unable to sleep. What's more, caffeine is habit-forming. Those who consume it regularly and stop suddenly may experience headaches and feel tired.

    One of the biggest concerns is the large amount of caffeine added to so-called energy drinks, like Red Bull. A 12-ounce can of cola has about 35 milligrams of caffeine. A similar serving of Red Bull contains more than three times that amount.

    The Institute of Medicine is also working on caffeine-safety measures. “Teenagers should not drink beverages that contain caffeine. They should be aware of caffeine's effects on health and on how the brain works. Take, for example, teenagers who consume caffeine to stay awake and study for a test. They will remember less of what they just studied,” said Stallings, a member of the institute.

    Companies that make products with added caffeine claim they do not advertise them to kids. However, there is no law to stop children from buying them. So the FDA needs to set limits on caffeine, especially in energy drinks. As for added caffeine in foods, the government should just say no. If not, the amount of caffeine should be printed on food labels to remind consumers. The government must do that.

    Doctors say kids should avoid caffeine. If you need extra energy, try these natural boosters: eat right, exercise, and get plenty of sleep.

Yawning（哈欠）sends out certain messages—either “Oh, this movie is boring" or "I probably need to get some sleep". But did you know that a yawn can also help your brain to cool down when it is so overheated?

    A new study, led by a research team of Princeton University, has indicated（表明）that yawning could be the brain's natural way of regulating temperature. People yawn more often when the temperature outdoors is lower than their body temperature but are less likely to yawn when it is hotter outdoors, according to Sciencedaily.com.

    The research team did an experiment on 160 people, 80 in summer and 80 in winter, to examine how often they yawned at different air temperatures. The study found that people yawned more often in winter than in summer. Scientists say that when the air temperature is lower outside the body, there is heat exchange between the overheated brain and the cool air. But when the air temperature is higher than or equal to the body, people are less likely to yawn because the hot air they breathe in will make the brain even hotter.

    When people yawn, their jaw is also stretched, which increases blood flow and may also help cool the brain.

    The study showed that the amount someone yawned could be related to the amount of time they spent outside. The longer they spent outside in summer, the less they yawn. Nearly 40 percent of participants yawned within their first five minutes outside, but after that the percentage was reduced to less than 10 percent.

    However, the result was the opposite in winter. The number of people who yawned increased when they spent more than five minutes outdoors. But the change was only slight compared to summertime.

    According to Gallup, this is the first report to show that yawning frequencies(频率) change depending on season. This could help us to understand better the way our brains work. It may also help us understand the reason why frequent yawning can sometimes be a sign of brain disease.

    WeChat, the Chinese social media smartphone app, saw an increase in user numbers of 41 percent year on year to 500 million at the end of last year, in a sign that parent company Tencent is extending its reach for the mobile Internet. As one of the largest Internet integrated service providers in Chinaand one of the most Internet users in China, Tencent's profit grew 24 percent to RMB 20.98 billion per year, slightly higher than forecasts, driven mainly by online gaming profits. It is unclear how much WeChat contributed to Tencent's profits but the app's growth is a strong indicator of the company's long-term health as it tries to adjust its business to be more suitable for mobile devices.

    "We extended our leadership in games and online media, and made breakthroughs in emerging platforms such as online security and mobile payments." Ma Huateng, Tencent chairman, said in a statement. WeChat is the second highest ranked social app in China, behind QQ, Tencent's another chatting app, which claimed to have 815 million registered monthly users at the end of 2014.

    Tencent has been unwilling to earn money through WeChat by flooding it with advertising, which could influence the users' experience. But this is expected to change. Some analysts anticipated(预期) that advertising would be introduced on a large scale later this year. Early attempts to test ads on the service have not always gone smoothly. After a BMW ad was introduced on some users' feedbacks in January, many users who were not targeted by the brand's marketing complained of "discrimination" by Tencent's data mining algorithm(数据挖掘算法). They claimed it unfairly treated them as not wealthy or successful enough to view the BMW ad.

    Poet William Stafford once said that we are defined more by the detours(绕行路) in life than by the narrow road toward goals. I like this image. But it was quite by accident that I discovered the deep meaning of his words.

    For years we made the long drive from our home in Seattle to my parents' home in Boise in nine hours. We traveled the way most people do: the fastest, shortest, easiest road, especially when I was alone with four noisy, restless kids who hate confinement(限制) and have strong opinions about everything.

    Road trips felt risky, so I would drive fast, stopping only when I had to. We would stick to the freeways and arrive tired.

    But then Banner, our lamb was born. He was rejected by his mama days before our planned trip to Boise. I had two choices: leave Banner with my husband, or take him with me. My husband made the decision for me.

    That is how I found myself on the road with four kids, a baby lamb and nothing but my everlasting optimism to see me through. We took the country roads out of necessity. We had to stop every hour, let Banner shake out his legs and feed him. The kids chased him and one another. They'd get back in the car breathless and energized, smelling fresh from the cold air.

    We explored side roads, catching grasshopper in waist-high grass. Even if we simply looked out of the car window, at baby pigs following their mother, or fish leaping out of the water, it was better than the best ride down the freeway. Here was life. And new horizons(见识).

    We eventually arrived at my parents' doorstep astonishingly fresh and full of stories.

    I grew brave with the trip back home and creative with my disciplining technique.

    On an empty section of road, everyone started quarreling. I stopped the car, ordered all kids out and told them to meet me up ahead. I parked my car half a mile away and read my book in sweet silence.

    Some road trips are by necessity fast and straight. But that trip with Banner opened our eyes to a world available to anyone adventurous enough to wander around and made me realize that a detour may uncover the best part of a journey-and the best part of yourself.

    We lived in a quiet neighborhood. One evening I heard a loud crash. Earlier my wife had asked me to the store for soft drinks. My teenage daughter Holly practiced her driving, so I sent her to the store in my truck.

    At dinner my son talked about how much he liked my truck. I enjoyed having it, but I said: "My heart is not set on that truck. I like it but it is just metal and won't last forever. Never set your heart on anything that won't last. "

    After hearing the loud noise, the whole family ran outside. My son shouted: "Holly crashed your truck."

    The accident took place in my own driveway. Holly had crashed my truck into our other vehicle(交通工具), the family van. In her inexperience, she had confused the brake(刹车) and the gas pedal(油门). Holly was unhurt physically, but she was crying, "Dad, I'm sorry. I know how much you love this truck." I held her in my arms as she cried.

    I still remembered how sad Holly was the night she crashed our truck, and how I comforted her. When Holly thinks back on her life, I want her to know that I love her a thousand times more than any piece of property(财产).

    I repaired the van, but the dent(凹痕) in my truck is still there today. Every day it reminds me of what really matters in my life.

At age 22, Hikari Oberman has already been a lifeguard for four years. Last week, Oberman talked to The Garden Island about how he helped save lives during a recent rescue.

On Dec. 30, Oberman and his coworker Cope were parked in their truck at Anini Beach when two workers ran up to them and said, "I think someone's getting stuck in the channel!"

"I grabbed our equipment. We started rolling out down there," Oberman said. When he got out there, Oberman found a standup paddler, a man in his late 30s, struggling against the current, with an elderly man holding tightly to the back of the paddleboard (冲浪板).

He said, "My coworker grabbed the standup guy. Meanwhile, I'm stuck with the older man. "

Normally, Oberman said he would pull the paddler up, lay him on the surfboard, climb up behind and paddle from there. He tried that technique at first and quickly realized it was not a practicable option. They are not going anywhere.

Waves hit against the extremely sharp reef very hard about 30 yards behind them, and the current was pulling them into it.

"It's right behind us. If I stop paddling, we're definitely going to be in that zone." He said.

They started making progress toward the reef, where they might safely be able to climb out. Oberman just focused on forward movement.

After about five minutes-"even though it felt longer" -Oberman said his partner had gotten the paddleboarder safely to shore and started coming back out to help.

"I look back, and I see our Jet Ski. He's finally coming in the channel. We're not going to have to worry about that now. "

It was a good rescue.

When asked what it feels like to save someone's life, Oberman responded, "I love it! That's why we do it!" But as exciting as it might be to perform a big rescue, he explained that the most important part of his job is to keep people from getting into trouble in the first place.