You may have heard of the American Dream, an ideal that has powered the hopes of Americans for generations.

    It began as a belief that the US was a land of opportunity, and that anyone could achieve success through hard work. At times, the dream has referred to home ownership, a good job, retirement security or each generation doing better than the last.

    Yet today, this concept seems to have greatly changed. As Time magazine pointed out, quite different from the older generation, many Millennials (the generation born after 1980) redefine(重新定义) the American Dream as “day-to-day control of your life”. They “prize job mobility, flexible schedules, any work that is more interesting than typing, and the ability to travel”, said the magazine.

    Home ownership, once the cornerstone of the American Dream, is becoming a smaller priority for this generation. Meanwhile, nearly 40% of them choose travel as part of their dream. And entrepreneurship(创业) is a rising favorite, as nearly 26% of Millennials consider self-employment as part of their dream.

    So what has led to this huge change?

    Many point fingers at the poor economy. “Modern young Americans seem bound to face a world stamped by ever narrowing opportunity and social stagnation(停滞),”noted The Daily Beast.

    “The rate of 16-to 24-year-olds out of school and out of work is unusually high at 15%. Many college graduates have taken jobs that don't require a degree,” Time reported.

    The magazine worries that these difficulties may lead to a lost generation who are “unable to ever truly find their feet on the corporation's ladder”.

    Dan Kadlec, a reporter of Time, sees Millennials as resetting their expectations.”This situation is different for young adults today,” he wrote. “A true American dream has to feel attainable, and many Millennias are feeling they can only attain a day-today lifestyle that suits them.”

    Last week, my granddaughter started kindergarten, and I wished her every success. But part of me didn't. I actually wanted her to fail in some ways because I believe that failure can be good for our learning process. Success is proving that you can do something that you already know you can do, or doing something correctly the first time, which can often be a problematic (存在问题的) victory. First-time success is usually a fluke (侥幸). First-time failure, however, is supposed to be the natural order of things. Failure is how we learn.

    In Africa they describe a good cook as “She who has broken many pots.” If you've spent enough time in the kitchen to have broken a lot of pots, probably you know a fair amount about cooking. I once had dinner with a group of cooks, and they spent time comparing knife wounds and burn scars. They knew how much credibility (可信) their failures gave them.

    I earn my living by writing a daily newspaper column. Each week I know that one column I write is going to be the worst column. I try my best every day. I have learned to love that column. A successful column usually means that I am discussing my familiar topic, writing in a style I am used to or saying the same things as anyone else but in a better way.

    My younger daughter is a trapeze artist (荡秋千演员). She spent three years practising a show, and she did it successfully for years. There was no reason for her to change it but she did anyway. She said she was no longer learning anything new and she was bored. And if she was bored, there was no point in subjecting (使……服从于) her body to all that stress. She risked failure and great public embarrassment in order to feed her soul.

    My granddaughter is a perfectionist. She will feel her failures, and I will want to comfort her. But I will also, I hope, remind her of what she learned, and how she can do better next time. I hope I can tell her, though, that it's not the end of the world. Indeed, with luck, it is the beginning.

    A recent study presents the possibility of “carbon farming” as a less risky alternative to other carbon capture and storage technologies. It suggests that a significant percentage of atmospheric CO₂ could potentially be removed by planting millions of acres of a shrub known as the Barbados nut（麻疯树）, in dry, coastal areas. But other experts doubted whether the Barbados nut would be able to grow well in sandy desert soils and absorb the quantity of carbon their models predict.

    The researchers behind the study say Barbados nut plantations（种植园）could help to reduce the local effects of global warming in desert areas, causing a decrease in average temperature and an increase in rainfall. If a large enough portion of the Earth were blanketed with carbon farms, these local effects could become global, capturing between 17 and 25 metric tons of CO₂ per hectare each year over a 20-year period.

    Carbon farms would not compete with food production if they were concentrated in dry coastal areas. In their analysis, oceanside desalination（海水淡化）plants provide a low-emission irrigation method. The study states that the Barbados nut is uniquely suited to growing in regions unsuitable for other crops .The plant, which produces a non-edible seed that can be used to create biodiesel（生物柴油）, is comfortable growing at temperatures exceeding 100 degrees Fahrenheit. It can also stand up to high levels of pollution in the soil, making waste water another potential source for irrigation.

    The cost of carbon farming is comparable to the costs associated with other carbon capture and storage technologies, the study claims. Wulfmeyer stressed that carbon farming could have “fantastic value for the local people” if international carbon markets pick up, promoting rural development and opening up the possibility of additional agriculture as the soil quality improves around the plantation.

    In an email, Van Noordwijk, a chief science advisor, questioned the growth rate and the atmospheric carbon capture rate assumed by the study's authors, calling the estimated carbon price of the plantations a “considerable underestimate”. “We are talking about a plant with a shrubby growth habit and a long track record of misleading farmers with production potentials that are not being realized,” he said, and “Even with abundant water, the nutrient storage in sandy desert soil is low. He added, “The estimated carbon price of this option already indicates that there are far better opportunities for reducing ongoing emissions from peatland（泥炭地）use and deforestation.”

    Teenagers' fitness is now a major concern, to which physical exercise is very important. It reduces stress and improves fitness. Exercise makes your body strong, and helps you to keep the right body weight. Sports scientists Dr. Helen Lopez offers the following advice to teenagers: “First, you need to find out your present level of fitness. Then you can design a programme that will help you become healthier.”

    Dr. Lopez suggests that there are three levels of fitness that need a change of lifestyle. “Overweight” means that the person gets very little exercise and often has a serious weight problem. “Inactive” mean that the person does not join in many physical activities, but is not seriously overweight. “Active” refers to people who take part in sports and other physical activities, but do not have a high fitness level.

    According to Dr. Lopez, overweight teenagers should keep active to keep healthy. “Ride a bike, play volleyball or basketball for a while, and go for a twenty-minute walk each day. All these will help to burn calories.” Inactive teenagers should do similar activities, but add some bending and stretching exercises, such as push-ups and sit-ups, starting with twenty of each a day. “Inactive people can take a little more exercise than overweight people because their bodies are stronger,” said Dr. Lopez. The same principle applies to active teenagers.

    Dr. Lopez suggests one hour a week or more on running and other forms of intensive exercise, together with fifteen minutes a day spent on stretching and bending activities. “These are really important in order to prevent injuries,” Dr. Lopez said. Some weight-training and other body-strengthening exercises could also be planned in the programme in order to increase the person's strength.

    My teenage son Karl became withdrawn after his father died. As a single parent, I tried to do my best to talk to him. But the more I tried, the more he pulled away. When his report card arrived during his junior year, it said that he had been absent 95 times from classes and had six falling grades for the year. At this rate he would never graduate. I sent him to the school adviser, and I even begged him. Nothing worked.

    One night I felt so powerless that I got down on my knees and begged for help. "Please God, I can't do anything more for my son. I'm at the end of my rope. I'm giving the whole thing up to you."

    I was at work when I got a phone call. A man introduced himself as the headmaster. "I want to talk to you about Karl's absences." Before he could say another word, I cried and all my disappointment and sadness over Karl came pouring out into the ears of this stranger. "I love my son but I just don't know what to do. I've tried everything to get Karl to go back to school and nothing has worked. It's out of nay hands. "For a moment there was silence on the other end of the line. The headmaster seriously said, "Thank you for your time", and hung up.

    Karl's next report card showed a marked improvement in his grades. Finally, he even made the honor roll. In his fourth year, I attended a parent-teacher meeting with Karl. I noticed that his teachers were astonished at the way he had turned himself around. On our way home, he said, "Mum, remember that call from the headmaster last year?" I nodded. "That was me. I thought I'd play a joke but when I heard what you said, it really hit me how much I was hurting you. That's when I knew I had to make you proud."

    (CNN)—This photograph of two men sharing a drink 30 meters below the water is part of an art project exploring the mysterious world of freediving—a form of underwater diving that relies on a diver's ability to hold his or her breath until resurfacing rather than on the use of oxygen tanks (氧气瓶).

    Each man, dressed in shirt, jeans and sunglasses, sits in a chair at the bottom of the Caribbean Sea with local sharks—harmless to humans—swimming just meters away. Of course, these aren't ordinary men, but freedivers: extreme athletes who dive on a single breath of air.

    American photographer Lia Barrett had been taking pictures of brave divers competing at the Caribbean Cup off the coast of Honduras, when she decided to create a fantastic underwater world in which humans go about everyday tasks—such as drinking coffee or riding bikes.

    "After the competitors had a great time in the new national and world records set at the competition, I took advantage of their breath-holding skills to do photo shoots I had only dreamed of before," said the 29-year-old.

    Perhaps unsurprisingly, Barrett is often asked whether the amazing pictures are Photoshopped. She laughs quietly as she insists they're 100% real.

    The picture of two men having coffee took 50 minutes to create, with the men receiving oxygen from standby assistants around every three minutes.

    "On the way back up, we were holding onto the table during our decompression (减压) stop in the strong current (水流)—it was quite a scene."

    The underwater models made an 11-minute stop on the way back to the surface, making sure they didn't rise too quickly and suffer decompression sickness—which can cause deadly blackouts (眩晕).