I had been following the yellowish-green markers for a “popular and easy” three-mile out-and-back hike. Immediately after the trailhead(山道的起点), the trail became very rocky and steep. But having read information about the hike, I knew within five minutes, I was supposed to reach the hike's first overlook.

    However, the overlook never arrived. Instead, I found myself lost in the woods. Pulling out my cellphone, I saw it read “no service”. I checked the last text message I'd sent to my mom. It read, “Conference ended…going for a small hike before my flight home this afternoon.” I put my phone away and kept moving and yelling, “Help! Is anybody out there?” Every so often, I'd stop to listen, but I never heard a reply.

    I got out my phone again. The battery was running out fast as it searched for a signal. I struggled to find a place where I could get service. When I did, I called my mom. It went through! In a shaky voice, I said, “Mom?” And then the call dropped. More than 1,500 miles away, my mom instantly knew something was wrong. She called the Denver Police Department and was directed to the US Forest Service.

    This was how I was introduced to John, an operator from the US Forest Service. Following John's instruction on the phone, I finally escaped from the woods. I breathed a sigh of relief. Then my phone rang, and it was John, making sure I was still going in the right direction. “By the way,” he said, “we've had your mother on hold this whole time. We know once you get down the mountain, you will absolutely want to give her a call.”

    We already know the fastest, least expensive way to slow climate change: Use less energy. With a little effort, and not much money, most of us could reduce our energy diets by 25 percent or more—doing the Earth a favor while also helping our wallets.

    Not long ago, my wife, PJ, and I tried a new diet—not to lose a little weight but to answer an annoying question about climate change. Scientists have reported recently that the world is bending up even faster than predicted only a few years ago, and that the consequences could be severe if we don't keep reducing emissions(排放) of carbon dioxide (CO₂ ) and other greenhouse gases that are trapping heat in our atmosphere.

    We decided to try an experiment. For one month we recorded our personal emissions of CO₂. We wanted to see how much we could cut back, so we went on a strict diet. The average US household(家庭) produces about 150 pounds of CO₂  a day by doing common-place things like turning on air-conditioning or driving cars. That's more than twice the European average and almost five times the global average, mostly because Americans drive more and have bigger houses. But how much should we try to reduce?

    For an answer, I checked with Tim Flannery, author of The Weather Makers: How Man is Changing the Climate and What it Means for Life on Earth. In his book, he had challenged readers to make deep cuts in personal emissions to keep the world from reaching extremely important tipping points, such as the melting(融化) of the ice sheets in Greenland or West Antarctica. "To stay below that point, we need to reduce CO₂  emissions by 80 percent," he said.

    Good advice, I thought. I'd opened our bedroom windows to let in the wind. We'd gotten so used to keeping our air-conditioning going around the clock. I'd almost forgotten the windows even opened. We should not let this happen again. It's time for us to change our habits if necessary.

    For grown-ups, an afternoon snooze(打盹) is often easier said than done. But many of us have probably experienced just how simple it can be to catch some sleep in a gently rocking hammock(吊床). By examining brain waves in sleeping adults, researchers reported in the June 21 issue of Current Biology, a Cell Press publication, that they now have evidence to explain why that is.

    “It is a common belief that rocking causes sleep: we fall asleep in a rocking chair soon and, since ancient times, we cradle our babies to sleep,” said Sophie Schwartz of the University of Geneva. “Yet, how this works had remained a mystery. The goal of our study was made up of two parts: to test whether rocking does indeed improve sleep, and to understand how this might work at the brain level.”

    Schwartz, Michel Mühlethaler, and their colleagues Laurence Bayer and Irina Constantinescu asked twelve adult volunteers to nap on a custom-made bed or “experimental hammock” that could either remain still or rock gently. All participants were good sleepers who didn't typically nap and did not suffer from excessive sleepiness during the day. Each participant took two 45-minute afternoon naps, one with the bed still and one with the bed in motion, while their brain activity was monitored.

    “We observed a faster transition to sleep in each and every subject in the swinging condition,” Mühlethaler said. “Surprisingly, we also observed a dramatic boosting of certain types of sleep-related brain waves.”

    More specifically, rocking increased the length of stage N2 sleep, a form of non-rapid eye movement sleep that normally occupies about half of a good night's sleep. The rocking bed also had a lasting effect on brain activity, increasing slow brain waves and bursts of activity known as sleep spindles(纺锤体).

    Schwartz and Mühlethaler say the next step is to find out whether rocking can improve longer periods of sleep and to find out whether it may be useful for the treatment of sleep disorders, such as insomnia(失眠).

    Chinese scientists recently have produced two monkeys with the same gene, Zhong Zhong and Hua Hua, using the same technique that gave us Dolly the sheep. These monkeys are not actually the first primates（灵长类）to be cloned. Another one named Tetra was produced in the late 1990s by embryo（胚胎）splitting, the division of an early-stage embryo into two or four separate cells to make clones. By contrast, they were each made by replacing an egg cell nucleus（原子核）with DNA from a differentiated body cell. This Dolly method, known as somatic cell nuclear transfer（SCNT）, can create more clones and allows researchers greater control over the edits they make to the DNA.

    Success came from adopting several new techniques. These included a new type of microscopy to better view the cells during handling or using several materials that encourage cell reprogramming, which hadn't been tried before on primates. Still, the research process proved difficult, and many attempts by the team failed. Just two healthy baby monkeys born from more than 60 tested mothers. This leads to many researchers' pouring water on the idea that the team's results bring scientists closer to cloning humans. They thought this work is not a stepping stone to establishing methods for obtaining live born human clones. Instead, this clearly remains a very foolish thing to attempt, it would be far too inefficient, far too unsafe, and it is also pointless.

    But the scientists involved emphasize that this is not their goal. There is now no barrier for cloning primate species, thus cloning humans is closer to reality. However, their research purpose is entirely for producing non-human primate models for human diseases; they absolutely have no intention, and society will not permit this work to be extended to humans. Despite limitations, they treat this breakthrough a novel model system for scientists studying human biology and disease.

    Why do you go to the library? For books, yes—but you like books because they tell stories. You hope to get lost in a story or be transported into someone else's life. At one type of library you can do just that—even though there's not a single book.

    At a Human Library, instead of books, you can "borrow" people. People with unique life stories volunteer to be the "books." For a certain amount of time, you can ask them questions and listen to their stories, which are as fascinating as any you can find in a book. (If you attend, make sure to review the habits that make you a good listener.) Many of the stories have to do with some kind of depressing topic. You can speak with a refugee, a soldier suffering from PTSD (创伤后遗症), a homeless person and a woman living with HIV. The Human Library encourages people to take time to truly get to know and learn from someone they might otherwise make a snap judgement about. According to its website, the Human Library is "a place where difficult questions are expected, appreciated and answered."

    The Human Library Organization came to be in Copenhagen, Denmark in 2000. Romni Abergel and his colleagues hosted a four-day event during a major Northern European festival. After the success of this event, Abergel founded the Human Library Organization, hoping to raise awareness among youth about depression, which has been growing ever since.

    Though there a few permanent human libraries, most aren't place at all, but events. Though many do take place at physical libraries, you don't need a library card—anyone can come and be part of the experience. There have been human library events all over the globe, in universities and in pubs, from Chicago to Tunis to Edinburgh to San Antonio. Check out the organization's Facebook page to see when the Human Library might be arriving near you.

    Many animal and plant species have become extinct and many more are in critical danger. Finding ways to protect the earth's wildlife and conserve the natural world they inhabit (居住) is now more important than ever.

    Dodo

    The Dodo is a classic example of how human caused damage to the earth's biology. The flightless Dodo was native to the Island of Mauritius in the Indian Ocean. It lived off fruit fallen from the island's trees and lived unthreatened until humans arrived in 1505. The easily controlled bird became a source of food for sailors and was attacked by animals introduced to the island by humans such as pigs, monkeys and rats. The population of Dodos rapidly decreased and the last one was killed in 1681.

    Rhinos

    The Rhino (犀牛) horn is a highly prized item for Asian medicine. This has led to the animal being hunted in its natural habitat. Once widespread in Africa and Eurasia, most Rhinos now live in protected natural parks and reserves (保护区). Their numbers have rapidly decreased in the last 50 years, and the animals remain under constant threat from poachers (偷猎者).

    The Giant Panda

    The future of the World Wildlife Fund's symbol is far from certain. As few as 1, 000 remain in the wild. The Chinese government has set up 33 panda reserves to protect these beautiful animals and made poaching them punishable with 20 years in prison. However, the panda's distinct black and white patched coat fetches a high price on the black market and determined poachers still pose (造成) one of the most serious threats to the animals continued existence.

    Whales

    The International Whaling Commission is fighting to ensure the survival of the whale species. Despite the fact that one-third the world's oceans have been declared whale sanctuaries (保护区), 7 out of 13 whale species remain endangered. Hunted for their rich supply of oil, their numbers have decreased to just 300. Collisions with ships, poisonous pollution and being caught in fishing nets are other major causes of whale deaths.

    Tigers

    The last 100 years has seen a 95% reduction in the numbers of remaining tigers to between 5, 000 and 7, 000 and the Bali, Javan, and Caspian tigers are already extinct. The South China tiger is precariously close to disappearing, with only 20 to 30 still alive. Like the Rhino horn, tigers' bones and organs are sought after for traditional Chinese medicines. These items are traded illegally along with tiger skins.