Against the assumption that forest fires in Alaska, Canada and Siberia warm the climate, scientists have discovered that cooling may occur in areas where burnt trees allow more snow to mirror more sunlight into space.

    This finding suggests that taking steps to prevent northern forest fires to limit the release of greenhouse gases may warm the climate in northern regions. Usually large fires destroyed forests in these areas over the past decade. Scientists predict that with climate warming, fires may occur more frequently over next several centuries as a result of a longer fire season. Sunlight taken in by the earth tends to cause warming, while heat mirrored back into space tends to cause cooling.

    This is the first study to analyze all aspects of how northern fires influence climate. Earlier studies by other scientists have suggested that fire in northern regions speed up climate warming because greenhouse gases from burning trees and plants are released into the atmosphere and thus trap heat.

    Scientists found that right after the fire, large amounts of greenhouse gases entered the atmosphere and caused warming. Ozone（臭氧）levels increased, and ash from the fire fell on far-off sea ice, darkening the surface and causing more radiation from the sun to be taken in. The following spring, however, the land within the area of the fire was brighter than before the fire, because fewer trees covered the ground. Snow on the ground mirrored more sunlight back into space, leading to cooling.

    “We need to find out all possible ways to reduce the growth of greenhouse gases in the atmosphere.” Scientists tracked the change in amount of radiation entering and leaving the climate system as a result of the fire, and found a measurement closely related to the global air temperature. Typically, fire in northern regions occurs in the same area every 80 to 150 years. Scientists, however, found that when fire occurs more frequently, more radiation is lost from the earth and cooling results. Specifically, they determined when fire returns 20 years earlier than predicated, 0.5 watts per square meter of area burned are soaked up by the earth from greenhouse gases, but 0.9 watts per square meter will be sent back into space. The net effect is cooling. Watts are used to measure the rate at which energy is gained or lost from the earth.

    Our warming planet is expected to face serious water crisis（危机）in the coming decades — which means each nation's natural resource will be more important than ever.

    Can you imagine printing food? Some scientists are trying to revolutionize the dining experience by doing this. They hope that having a 3D printer in the kitchen will become as commonplace as the microwave. Scientists say that they are easy to use:you simply have to select a recipe and put the raw food "inks" into the printer. You can also change the instructions to make the food exactly how you want it. This means that it would be very quick and easy to create tasty and nutritious meals.

    They say that if people used 3D printers to create meals there would be less need for traditional growing, transporting and packaging processes as food production would be a lot easier. For example, alternative ingredients (原料) such as proteins from insects could be changed into tasty products. And as is known,those traditional activities are not beneficial to our surroundings.

    This technology could also help people who suffer from dysphagia (a swallowing disorder).The patients could program the printer and softer versions would be made so that they would not have trouble swallowing them.

    However,some people think that using 3D-printed foods would be a disaster. It could take away many jobs,including those for growing,transporting and packaging food. Imagine a world where there was no need for farming or growing crops and the same tastes could be printed from a raw "food ink". Likewise, traditional cafes and restaurants might lose business. Also, there are concerns about the nutritional value of printed food:is it really possible to get the nutrients we need from food-based inks?

    What's more, cooking and eating together with family and friends has long been a traditional and enjoyable activity. It is hard to imagine a world where the pastime of cooking is dead and meals can be created at the touch of a button.

    “Oh，my god.Are you serious?”

    That's a reaction I often get when people hear the tale of my childhood.

    It's a story I don't often share.Growing up in a bad home, I learned to protect myself by not speaking up.I've seldom said anything about how badly I was treated and hurt as a child. I don't talk about how my name was changed at least three times, what it was like to live in my van(箱式货车), or how I've struggled with anxiety, depression, and wanting to kill myself. But I learned to start speaking up for myself. I went on to earn two graduate degrees and I will complete my Doctor's degree this year. I've also become a widely published author. So，how did I get to where I am today?

    What's helped me is surrounding myself with caring, loving people. I've learned day-to-day skills through research, trial and error, and with the help of skilled professionals. They've taught me how to slow down，to breathe，to be thankful for what I've got.They're the ones who make my goals possible.They have also taught me to turn my past experiences into strength-to make the negatives into positives.

    My hope is that sharing my story might help others to see what is possible even in the darkest of times and help others to speak out.I don't think I'm in any way special or unique. I'm a common man，no more deserving than anyone else.But for far too long，I've been afraid that others think I'm damaged goods.I've worried about how I might be treated differently.

    Pain and fear teach us to be silent.It's time for that to change.

    I don't know what tomorrow might bring.But one thing I've learned is that if we can hold on and find help，if we find ways to get through the day and speak up，we'11 not only survive，but become stronger than before.

    Our very survival can be an inspiration all on its own.And with love of my friends，I look forward to so much more than completing my education—I look forward to the future.

    Even though it's not the most popular time of year to get married, I allow my thoughts to wander and consider the most unusual marriage habits across the world.

    In some parts of India it is believed that ghosts can stay with certain people of the living world. In general, girls who are born with a baby tooth and girls who are very ugly or have some facial damage are believed to be owned by ghosts. The only way to free from the ghosts is for the girl to marry an animal, typically a goat or a dog. She is free to marry a man later on, when the ghosts are proven to be freed from her. I wonder who makes this decision and how they come to their conclusion.

    In Korea, it is a custom for grooms to request that their successfully married friends carve them wooden ducks as a symbol of great marriage. Hand-carving a wooden duck can't be easy. This leads me to wonder why it's a duck and not another animal.

    Imagine being as young as 5 and already your parents are sending you to a fat farm where you are forced to eat too much food until you vomit (呕吐). Then, the old woman watching you eat forces you to eat that vomit. This is not a TV show. This is really happening in some parts of Africa. Men there want women fat; the fatter the better. It doesn't matter if it ruins their health or make them live shorter lives. All that matters is that the woman is as large as possible in order to sell her for a high price when she reaches the age for marrying.

    Cold weather during winter months may keep many people from leaving home and running in the open air.

    However, a new study shows that the drop in temperature is a good reason to run. In fact, researchers say, running in cold weather helps improve one's performance.

    Many people say running in the winter can be difficult. Two reasons are the low temperatures and bitter winds. Yet many runners might find it easier than running in hot weather.

    That could be because lower temperatures reduce stress on the body. When you run in cold weather, your heart rate and the body's dehydration (脱水) levels are lower than in warmer conditions. The body needs less water on a cold day than in warm weather.

    This information comes from sports scientists at St. Mary's University in London. John Brewer is a professor of applied sport science at St. Mary's.

    For this study, he and other researchers put a group of people into a room they called an “environmental chamber.” The researchers then recreated summer and winter weather conditions in the room. The test subjects were asked to run 10,000 meters under both conditions. Brewer says he and his team recorded biological measurements of the runners.

    “We've got a group of subjects into the environmental chamber, we've changed the conditions to replicate the summer or winter and we've got them to run a 10km under both of those conditions and taken various measurements on each runner while they've been completing their 10km.”

    Brewer says every movement runners make produces heat. He explains that one way in which we lose heat is by sweating. The body loses heat through droplets of sweat. He says the body also loses heat by transporting the blood to the surface of the skin.