Houses fall down. Trees fall over. Large holes form in the ground. Could Alaska be sinking? That's what some villagers in Alaska have been asking themselves recently and scientists think they know why. Warmer temperatures may be causing Alaska's frozen ground to thaw (解冻).

    About 85 percent of Alaska's land surface has permafrost (永久冻结带). Permafrost supports the ground above it—including trees, houses, and roads. But why is the permafrost thawing?

    Some scientists say that human-caused pollution is leading to global warming. And most scientists agree that Alaska has been getting warmer. They say that the warmer temperature is causing permafrost to thaw in some areas. The thawing permafrost can cause problems for people, plants, and animals.

    The collapsing (倒塌) is a problem in the villages in Alaska which are built on permafrost, and some of them may have to move to safer ground, where there is no permafrost.

    The Alaskan town of Glennallen saw its old post office collapse. And, according to James Walters, a permafrost expert at the University of Northern Iowa, house-moving companies have been very busy.

    “Melting permafrost can also destroy trees and forests,” Walters said. “When holes in the ground form, trees fall into them and die. This could turn a forest into a swamp (沼泽), and animals which need the forests will have to move elsewhere.”

    “The melting could cause severe problems.” Walters says, “This could take hundreds of years, but in the end Alaska will look quite different from what it looks like now.”

    Today I went to Berkeley, near our old neighborhood. I was a bit surprised by the increased number of homeless (alternatively housed) people walking around. I remember there are more in certain areas. So the first man who asked me for money got all my single bills. So when the second man asked me two minutes later, I said I was out because I gave all I had to the previous person.

    I was headed to the grocery store for a coffee and after I left the store I walked out to find him as he had asked me for something because he was hungry and I invited him to go into the grocery store with me.

    When I asked him what he wanted to eat, he just asked for vegetable and rice. He talked about how much better the vegetables were as we waited for our number to be called. While we waited he told me that he had slept outside last night on the sidewalk, that it was not good, and that he had come from Rwanda and was alone.

    He was a gentleman. When I asked if he wanted more he said, this bowl of food would last him the whole day.

    I don't know what his circumstances were before he came to California, and wandering and begging on the streets could somehow be better because you just never know what had happened to him. He seemed like a kind soul who just needed some help like we all do. I am grateful I did a little to help him today.

    Nowadays wind is useful. Think about the different ways that people use the wind. You can use it to fly a kite or to sail a boat. Wind is one of our cleanest and richest power sources, as well as one of the oldest. Evidence shows that windmills began to be used in ancient Iran back in the seventh century BC. They were first introduced to Europe during the 1100s, when armies returned from the Middle East with knowledge of using wind power.

    For many centuries, people used windmills to grind wheat into flour or pump water from deep underground. When electricity was discovered in the late 1800s, people living in remote areas began to use them to produce electricity. This allowed them to have electric lights and radio. However, by the 1940s, when electricity was available to people in almost all areas of the United States, windmills were rarely used.

    During the 1970s, people started becoming concerned about the pollution that is created when coal and gas are burned to produce electricity. People also realized that the supply of coal and gas would not last forever. Then, wind was rediscovered, though it means higher costs. Today, there is a global movement to supply more and more of our electricity through the use of wind.

    You've got your fancy new suitcase and you're ready to take it with you on your travels across the globe.

    You get to the airport, quickly moving through the crowds on the uneven pavement, rushing to check in. Then, your heart sinks when you realize your new suitcase has got a serious case of the wobbles (摇晃).

    Why does this happen?

    Scientists from the Universite Paris-Diderot in France investigated this matter and published their findings in the science journal Proceedings of the Royal Society A. They also suggested some solutions to overcome this modern-day problem.

    To learn more about the issue, they put a suitcase on a treadmill (跑步机) and observed what happened.

    It was soon noted that the "wobble" was actually a result of repeated actions that caused the suitcase to sway from side to side. They discovered that if one of the wheels encountered an obstacle such as a small bump, it jumped into the air for just a moment and then banged back down to the ground. That second action caused the opposite wheel to lift off the ground and then to bang back down, causing the first to lift again and so on. This swaying increased as the luggage was pulled along.

    "The suitcase is a fun way to tackle the problem, but the study would be the same for any trolley with two wheels or blades (桨叶)," Sylvain Courrech du Pont, lead author of the study, told BBC News. "So it will be the same for a caravan (大篷车) or maybe also for airplanes."

    Instead of slowing down when we see a rocky part of the path, the scientists recommended doing the exact opposite and speeding up. This is because going faster gives the wheels less time to rise and fall, preventing the case from swaying. They also said that reducing the angle of the suitcase by lowering its handle to the ground would help keep it steady.

    "These findings could help researchers simulate and design better rolling suitcases and other pulled trolleys, such as towed trailers," Courrech du Pont added.

With these masterminds (智者) working on perfecting our suitcase problems, wobbly luggage may soon be a thing of history, leaving us to enjoy our travels.

    The holidays are the best time to ask the elders in your family for advice. For most people, the approaching holiday season includes more time with the extended family, including the elder generation.

    Unfortunately, older adults are often unseen in the popular media. Yet there's a big body of evidence that shows the benefits of older adults' wisdom and the value of developing communication across generations.

    First, over the course of human history, older people have played very important roles as advice-givers. Anthropological (人类学) research shows that survival in pre-literate societies was dependent on the knowledge of the oldest members.

    In recent times, most of the researches about intergenerational communication occur within formal programs, such as ones including older adults in public schools or having youth visit assisted living facilities. Also, you can apply many of the lessons of the researches to your own family gatherings.

    There is clear evidence that it is good for young people to spend time with older adults. The youth who participated in intergenerational programs showed more respect toward older adults, less anxiety, and higher self-esteem. Research also shows that interacting with younger people is good for older adults. A systematic review found that older adults who participated in intergenerational programs were likely to experience more satisfaction with their lives, higher self-esteem and fewer symptoms of depression. Interactions during intergenerational programs can be positive even when an older adult is experiencing memory or cognitive problems.

    Having children teach computer or video games to the older generations can be a fun way to spend time together. A study found that intergenerational games can help family members to bond. Another idea is to encourage the youth to ask older family members for their advice about life.

    The youth can ask older adults specific questions about the lessons they learned from their life experiences.

    The take-home message is that time with older relatives is one of the true gifts of the holiday season. Make the most of it by spending time with the older generation!

    The idea behind Facebook is to make us feel connected all the time. But in my research, I've found that the truth is quiet different.

    Technology, it turns out, has made being alone seem like a problem that needs soling. When young people are alone, even for a minute or two, they feel the need to connect to get on Facebook or some other social networks and chat. But in connecting, they often end up feeling more isolated. Why? Because by being in constant (不断的) connection, they lose the ability to feel satisfied with their own company (独处).

    Facebook can help us keep in touch with our friends, but we too often use it instead of spending face to face time with them. And since we feel the need to keep up with them online, we don't have moments of loneliness where we can collect our thoughts and learn how to be comfortable being alone.

——Sherry Turkle, Profescer

    Facebook connects more of us to more of our friends and family in more places than we have ever been connected before. Yes. Facebook is a huge time sink -maybe the biggest ever. Many people post useless stuff. And seeing too much of your friends lives can make you jealous (嫉妒的), but it won't make you lonely.

    Jane, a former student of mine, who is back in New York after living abroad for ten years told me that Facebook helps her a lot. The first time she moved back to New York from abroad, she felt disconnected from her family and friends. now because of lots of photos and information updates (更新), she knows what is happening with her friends all the time.

    In fact, if you are lonely in real life, you will be lonely online as well.

——Sree Steniveasan, Chief Digital office