Last year I ruined my summer vacation by bringing along a modern convenience that was too convenient for my own good: the iPad. Instead of looking at nature, I checked my email. Instead of paddling a small boat, I followed my Twitter feed (推特简讯). Instead of reading great novels, I stuck to reading four newspapers each morning. I was behaving as if I were still in the office. My body was on vacation but my head wasn't.

    So this year I made up my mind to try something different: withdrawal (退出) from the Internet. I knew it wouldn't be easy, since I'm bad at self-control. But I was determined. I started by giving the iPad to my wife.

    The cellphone signal at our house was worse than in the past, making my attempts at cheating an experience in frustration (沮丧). I was trapped, forced to go through with my plan. Largely cut off from e-mail, Twitter and my favorite newspaper websites, I had few ways to connect to the world except for radio and how much radio can one listen to, really? I had to do what I had planned to all along: read books.

    This experience has had a happy ending. With determination and the strong support of my wife, I won in my vacation struggle against the Internet, realizing finally that it was I, not the iPad, that was the problem.I knew I had won when we passed a Starbucks and my wife asked if I wanted to stop to use the Wi-Fi. “ I don't need it,” I said.  

    However, as we return to post -vacation life, a harder test begins: Can I continue when I'm back at work? There are times when the need to know what's being said right now is great. And I have no intention of giving up my convenience completely. But I hope to resist the temptation (诱惑) to check my e-mail every five minutes, which leads to checking my Twitter feed and a website or two.

    I think a vacation is supposed to help you reset your brain to become more productive. Here I hope this one worked.

    It's official. Denmark—as well as being the world's best country to live in for women with the second-happiest people and one of the best healthcare systems in Europe—has the most contented babies. Or, at least, the ones who cry the least. According to research published in the Journal of Pediatrics, Danish, German and Japanese babies cry the least, while British, Canadian and Italian babies cry the most.

    “I'm not surprised,” Danish parenting expert and co-author of The Danish Way of Parenting Jessica Alexander tells me. “The first year of a child's life is considered so important in Denmark. Danish parents are much less stressed because they get good maternity and paternity leave (孕产假). The atmosphere is much calmer and, if mothers are getting more time off, that goes hand in hand with less stress, more contact, more routines and less crying.” She pauses before throwing in a final tip: “Oh, and Danish babies sleep outdoors a lot.”

    In Denmark, a woman is given four weeks pregnancy leave followed by 52 weeks of paid leave that can be shared between parents. And Alexander thinks there is another important reason why Danish babies cry less: breastfeeding. “It's just the done thing in Denmark,” she says of a country that has the world's highest breastfeeding rates. “In other countries, there are continual discussions about whether you should or shouldn't breastfeed. In Denmark, breastfeeding has never gone out of style. And everyone does it for a year.”

    For Iben Sandahl, Alexander's co-author, it comes down to the Danish attitude to life in general. “We are an honest and pure people,” she tells me. “We are surrounded by social support and are less likely to become angry, sad or annoyed when our babies are crying. And we are good at embracing (拥抱) all kinds of feelings, so we aren't scared. Instead, we try to connect with the babies when they cry. It's how babies communicate and it's about trying to understand it.”

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    Even if trees cannot walk, they are still on the move.

    In parts of the Arctic, entire forests are moving northward. Across the Arctic, temperatures are rising faster than anywhere else in the world. As that happens, the tree line that marks where forests stop and the treeless tundra(冻土地带) starts has been shifting northward. Trees growing along the tree line must protect themselves from the cold wind. To do this, plants tend to grow horizontal(水平的) branches low to the ground. The energy it takes for trees to grow this way means they don't have enough energy to make seeds.

    But as Earth's climate has been warming, trees no longer have to just grow horizontally. Many can instead grow up toward the sky. This takes less energy. And with all the leftover energy. these trees have started producing more seeds. This happens especially in places where the white spruce(白云杉) grows.

    White spruce, which is a North American tree, is quite able to produce a lot of seeds, which can move long distances in the wind. When wind-blown seeds end up on the tundra beyond the tree line, they eventually can sprout(发芽) new trees. This explains how a forest can move. Of course, the process would work only if the tundra were warm enough. But in recent years, the whole planet has been warming.

    New trees will provide shelters for some snow, keeping the sun's rays from making the white surface disappear. Instead, the trees absorb the sun's heat. This warms the surrounding air. The extra warmth encourages even more trees to produce seeds. That further boosts a forest's ability to expand. In addition, more trees will trap more snow, preventing much of it from being blown away. Snow can trap heat in the soil below, which encourages trees to grow. The recent rise of temperature has helped more trees grow. The recent rise of temperatures has helped more trees grow past the tree line. People worry about impacts on the animals that depend on frozen conditions for food and shelter.

    A new study suggests that people who drank a certain amount of alcohol（酒）had a lower risk of cancer and death than those who drank more or none during a nine-year period. And with each additional drink a week, the risk of cancer and death from any cause increased, the scientists reported.

    However, the study found only an association between alcohol and cancer and death, and did not prove cause and effect, the researches said. What sets the new study apart, said lead study author Andrew Kunzmann, is that previous studies looked at cancer and death separately. “What our study does is combine the two outcomes together and we find that lighter drinking is associated with the lowest risk of cancer or death,” Kunzmann said.

    But Kunzmann noted that the participants（参与者）were all older adults. That means that “we're not really showing what happens in younger people if they drink,” he said. Also, it's difficult to account for other lifestyles that could have affected the results. “These could also influence health. But the results did take into consideration differences in diet, smoking and education among participants,” Kunzmann noted.

    The researchers said that they hope their study sparks conversation about reducing the suggested alcohol intake in countries' guidelines. “We're not telling people what they can or can't do or what they can or can't drink,” Kunzmann said. “We're just trying to give them reliable evidence so that they can make their own informed, healthy decisions.”

    Until recently, scientists had mapped only about 20 percent of the sea floor. But our knowledge of the deep seas is changing because of information from satellites. Scientists have produced a new map that provides a detailed picture of the oceans. The map is expected to help oceanographers (海洋学家), industry and governments.

    The new map is twice as detailed as the map made 20 years ago. David Sandwell is a geophysics professor at the University of California. He and other scientists worked on the mapping project. He says they turned to space to look deeper into the ocean.

    The scientists collected and studied information from two satellites. Some of the data came from the European Space Agency's Cryo-2 satellite. It was placed in Earth's orbit to watch sea ice. The other satellite is the American space agency's Jason-1. It is studying the surface of the oceans. Scientists combined the satellite data with images gathered by sonar (声波定位仪) equipment on ships. Sonar works by sending sound waves through the water. When the sound waves hit an object, its presence is confirmed.

    The new map shows the sea floor as it has never been seen before. It shows thousands of underwater mountains and places where continents pulled apart. It shows where earthquakes were active many years ago. They all are buried deep underneath the ocean floor.

    David Sandwell says the map is a powerful tool for fisheries, those interested in protecting the environment and for oil exploration.

    “The petrol exploration industry is interested in how to reconnect the continents, bring them back together tectonically so you can map the basins （盆地）on one continental edge—say, Africa—and use that to establish where the similar basin would be on the other continental edge in South America.”

    If scientists know that information, they may be able to find oil fields. The new data also will help scientists improve their estimates of ocean depths. This information can help ships travel safely and improve military operations and scientific projects worldwide.

    Mr. Sandwell thinks scientists will make many more discoveries as they examine the new map and the information it provides.

    Walking routes that are quicker and cheaper than the Tube in London

    Love to shop? You can walk between Knightsbridge and fashionable Sloane Square in around 10 minutes—much simpler than swapping lines at South Kensington.

    Don't fall into the trap of taking the Piccadilly line between Covent Garden and Leicester Square. It takes just four minutes to walk and you'll avoid the queues for the lifts at Covent Garden.

    *Use a Santander Cycle for just £2

    It costs £2 to access Santander Cycles for 24 hours. The first half hour is free each time you hop on a new bike, which means you can make multiple trips in one day and still pay only £2.

    *Hop on a bus

    Buses don't just offer a scenic way of getting around London—they're easy on the wallet too! A single fare costs just £1.50, while unlimited bus travel on a contactless card costs £4.50.

    Make the most of the hopper fare, which allows you to make a second bus journey for free within an hour of travel.

    *Go contactless for the cheapest fare

    If you have to take the Tube, use the same contactless card all day long to make the most savings when making multiple journeys. Contactless card users benefit from a daily cap (上限).