The American Academy of Pediatrics (AAP) (儿科学) just released its updated guidelines for children's media use.

    The recommendations reflect what all parents know: children need less screen time, which indicates that they desperately need more free time to develop their imagination, a sense of wonder and discover their passion and purpose.

    Our children are over-stimulated, over-scheduled and under pressure to perform academically and beyond school. This weakens their ability to build creative thinking skills essential to self-discovery. Creativity occurs when kids have time for curiosity and exploration. With children spending up to eight hours a day on media devices and additional hours engaging in scheduled activities, opportunities for growth disappear.

    What we are not so sure about is how to get our kids to want the free, screenless time which we know will benefit them. It may sound counter-intuitive (违背直觉的) but today's kids need coaching to experience and discover the benefits of free time.

What came to parents easily a few decades ago has become a challenge for our generation. It's not that yesterday's parents knew more about child development; they simply had fewer choices. Boredom and relaxation were an inescapable part of daily life. Today, they mean, "I'm a bad parent and not doing enough to get my kid ahead."

    Recently, I had an eye-opening revelation while watching my 11-year-old daughter play in a softball game. I have six children and have attended dozens of such game. I know the drill—or thought I did. Families settled in for the day with lawn chairs, cold drinks and cousins. These brothers and sisters would gradually chat with each other. Games of catch and hide-and-seek began, and friendships were formed then. At crucial moments, the newfound friends turned their attention to the field to cheer on their teams.

    But that wasn't happening. Though there were at least 15 children by the sidelines (球场边线), I didn't hear any of them. They sat in silence using their individual tablets (平板电脑). Even with the score tied in the final inning (垒球比赛的一局), not a single child watched the game or spoke to each other. The situation was strange and revealing: Kids have more planned activities and passive entertainment at their fingertips than ever before, but less free time to dream, imagine and focus on what they truly love.

I understand that making time for "nothing" is difficult in a world where we are constantly worried our kids will fall behind if they aren't good at academics. But I refuse to sit back and watch this loss of childhood. We are taking back childhood. Imagination needs time and space to blossom.

If your kids are like mine, asking them to imagine will at the beginning be difficult. That's because they haven't developed the skills and muscle memory to make it second nature. I hope the AAP guidelines prompt all of us to set needed screen time limits for our children. Personally, I am practicing strategies to "develop imagination" in my children. Imagination, like a sport, requires practice, training, motivational speeches, rewards and extreme patience.

    Scientists from the University of East Anglia have identified four new man-made gases that are contributing to the damage to the ozone(臭氧) layer. Two of the gases are accumulating at a rate that is causing concern among researchers.

    Worries over the growing ozone hole have seen the production of chlorofluorocarbon (CFC) gases restricted since the mid 1980s. But the precise origin of these new, similar substances remains a mystery.

    Lying in the atmosphere, the ozone layer plays a critical role in blocking harmful UV rays, which cause cancers in humans and reproductive problems in animals.

    Scientists from the British Antarctic Survey were the first to discover a huge “hole” in the ozone over Antarctica in 1985. The evidence quickly pointed to CFC gases, which were invented in the 1920s, and were widely used in refrigeration. Extraordinarily, global action was rapidly agreed to deal with CFCs and the Montreal Protocol to limit these substances came into being in 1987. A total global ban on production came into force in 2010.

    Now, the newly discovered four new gases can destroy ozone and are getting into the atmosphere from as yet unidentified sources. Three of the gases are CFCs and one is a hydrochlorofluorocarbon (HCFC), which can also damage ozone.

    The research has shown that four gases were not around in the atmosphere at all until the 1960s, which suggests they are man-made. The scientists discovered the gases by analyzing polar snow pack. Air from this snow is a natural archive of what was in the atmosphere up to 100 years ago. There searchers also looked at modern air samples, collected at remote Cape Grim in Tasmania.

    They estimate that about 74,000 tonnes of these gases have been released into the atmosphere. Two of the gases are accumulating at significant rates. However, they don't know where the new gases are being released from and this should be investigated. Possible sources include chemicals for insecticide (杀虫剂)production and solvents (溶液) for cleaning electronic components. The three CFCs are being destroyed very slowly in :the atmosphere—so even if emissions (散发)were to stop immediately, they will still be around for many decades to come.

    Of the four species identified, CFC-113a seems the most worrying as there is a very small but growing emission source somewhere, maybe from agricultural insecticides. We should find it and take it out of production.

    "Cleverness is a gift while kindness is a choice. Gifts are easy – they're given after all. Choices can be hard." –– Jeff Bezos.

    I got the idea to start Amazon 16 years ago. I came across the fact that the Internet usage was growing at 2,300 percent per year. I'd never seen or heard of anything that grew that fast, and the idea of building an online bookstore with millions of titles was very exciting to me. I had just turned 30 years old, and I'd been married for a year. I told my wife MacKenzie that I wanted to quit my job and go to do this crazy thing that probably wouldn't work since most start-ups don't, and I wasn't sure what to expect. MacKenzie told me I should go for it. As a young boy, I'd been a garage inventor. I'd always wanted to be an inventor, and she wanted me to follow my passion.

    I was working at a financial firm in New York City with a bunch of very smart people, and I had a brilliant boss that I much admired. I went to my boss and told him I wanted to start a company selling books on the Internet. He took me on a long walk in Central Park, listened carefully to me, and finally said, "That sounds like a really good idea, but it would be an even better idea for someone who didn't already have a good job." That logic made some sense to me, and he persuaded me to think about it for 48 hours before making a final decision. Seen in that light, it really was a difficult choice, but finally, I decided I had to give it a shot. I didn't think I'd regret trying and failing. And I believed I would always be haunted(萦绕)by a decision to not try at all.

    After much consideration, I took the less safe path to follow my passion, and I'm proud of that choice. For all of us, in the end, we are our choices.

    Everyone should be so lucky as to have a friend like Francia Raisa. On Thursday, singer and actress Selena Gomez, 25, used Instagram to explain why she was "laying low" this summer. She posted a photo of herself in a hospital bed with her friend Francia Raisa holding hands. She said she recently received a kidney transplant from her best friend because of complications(并发症) from lupus(狼疮), an autoimmune disease, which means it is the result of the immune system attacking normal tissue, including the kidneys, brain, heart and lungs.

    People with lupus may first experience tiredness, joint pain or a little bit of rash(皮疹) on their bodies and can go for a long time before their doctors realize it is more serious. Many people see two or four doctors before the real problem is picked up. According to Dr. Kyriakos Kirou, roughly a third to one-half of people with lupus develop kidney disease, and up to one in five of them will eventually need a transplant, sometimes because they weren't treated with effective drugs to prevent the immune system from attacking the kidneys. Though Gomez said that she was "very well now," she warned about the dangers of not taking medical diagnoses seriously, like she initially did.

    Her Instagram post also called attention to two major health topics: the need for living organ donators and the fact that Gomez represents three groups more likely to be diagnosed with lupus and lupus-related kidney disease. Nine out of 10 people diagnosed with lupus are women, and most develop the disease between the ages of 15 to 44. And lupus is two to three times more common among women of color, including Hispanic women, according to the Lupus Foundation.

    Raisa is Latina, and Gomez's father is of Mexican origin. While it's not essential that the organ donator and receiver be of the same ethnicity, people who share a similar background sometimes are better matched, according to data from the United Network for Organ Sharing.

    After photographer Monni Must's daughter Miya died, the sad mother adopted her black dog, Billy Bean. As Billy became increasingly weak, the thought of its dying was just more than Must could handle. So she decided to clone the dog. “I feared everyone was going to forget Miya," she said, "and my other daughters thought I had completely lost my mind."

    Billy's cells were shipped to ViaGen Pets, a Texas company that provides the cloning service. With more than $50,000, Must picked up a new puppy. "The dog has a real soul and is everything my daughter was—fun, social and kind," she said. "I feel that I still have that touchable connection and not just a spiritual connection.”

    Cloning animals is hardly new. But the recent news that singer Barbra Streisand had cloned her dog grabbed international headlines. People for the Ethical Treatment of Animals(PETA) president Ingrid Newkirk issued a statement saying she would love to talk her out of cloning, noting that millions of wonderful dogs are getting old in animal shelters every year or dying in terrifying ways when abandoned.

    Normally, a doctor takes a tissue biopsy(组织活检), a piece of skin and muscle about the size of a pencil eraser, from the dog. The next step is to take an egg cell from a donor dog, remove the egg's nucleus, and insert DNA from the pet to be cloned. When an embryo(胚胎)develops, it is transplanted in the body of a mother dog.

    In the basic cloning procedure, scientists take an entire adult cell and put it into an egg that's been relieved of its own DNA. The resulting embryo is a clone. However, in many animals, only one in 100 cloned embryos ever leads to a live birth. Some embryos die in the IVF dish or in the mothers bodies. Of those that are born, a few suffer from abnormalities and quickly die. Besides, pet cloning doesn't mean copying everything of your beloved pets.

    Mr. King lived with six hundred wild animals on the Greek Island of Kyklos. Ever since he left school, he had traveled all over the world collecting animals for his own zoo. He hoped to collect two examples of every kind of animal on his island. But he was afraid that people would find him someday.

    He wrote books about his travels and about his animals that he collected. The money from the books helped to pay for all the food those animals ate.

    One day, when Mr. King was out looking for drinking water, he found oil. He needed money for his travels and for his zoo, and a little oil would buy enough water for what he needed all his life, but he knew that if he told anyone else about it, it would be the end of his zoo and his life's work. So he decided not to tell anyone else about what he had found, because oil and water couldn't mix.