Since 2008, hunters have illegally killed more than 3000 rhinos in South Africa. The International Union for Conservation of Nature warns that rhinos may die out by 2026. People who hunt and kill illegally are called poachers. The most effective way to watch for and prevent illegal hunting is from the air. However, piloted flights are too costly. Fortunately, some Spanish college students have invented a drone (无人机) that can observe more places than a plane.

    Arnau Garcia is an aeronautical (航空学的) engineering student at the Polytechnic Institute of Catalonia, in Spain. He says observers from the air have trouble finding poachers when they hide under the trees. Mr. Garcia and other students have worked with the drone manufacturer HEMAV to help find the hidden poachers. They make it by using the thermal camera, which is especially sensitive to body heat. Even when the poachers keep still, it can also keep track of them.

    The drone can fly in the wind up to 55 kilometers per hour. It has an autopilot system, so it memorizes the flight path. The drone also has a microphone, a video camera and a GPS system. These permit it to report accurately where a picture is taken. After each flight, the drone can bring back detailed information about where rhinos are found, the conditions of water and plants in the area, and the positions of suspected poachers.

    Experts say the drone can fly as far as 70 kilometers from the base. It means that it could quickly observe large areas for poachers. However, the same search operation would take days for human observers. Thanks to the drone, many poachers have been caught and the number of rhinos is on the increase. In addition, HEMAV has received an increasing number of orders for the drone. Even South African national park officials attempt to fill the air with drones.

    Travelling around the world with children is difficult enough, while attempting it without using motorized transport is even more of challenge．Even so, Dario Schworer a 42-year-old climatologist and mountain guide, and his 33-year-old wife Sabine are on a journey to do just that．

    The Swiss couple want to travel across the world's oceans and climb the highest mountain on every continent to promote Earth-friendly ways of life．

    "We are collecting good examples of dealing with climate change and living in harmony with nature and we want to spread such ideas．" Schworer said．"We want to help people affected by global warming and to inspire children for the future．"

    Recently after having spent three months teaching children in the Everest region, the couple want to show it is possible to travel through the world's climate zones using just human-power and forces of nature．

    In the 47 countries they have visited they have collected 22 tons of trash, taught people in Ecuador how the sun's rays can be used to clean water and inspired a person in Chile to build a house on water with recycled plastic bottles as a foundation．They have also collected trash in the mountains of Nepal with school children．

    So far they have communicated with 45,000 children from South America, Australia and Asia, giving presentations about the importance of recycling and using alternative energy like solar and wind power．

    When they began their adventure in 2003 they had no children of their own．But since then two has become five: daughter Sabine is now five years old, Andri was born in Chile and baby Neo was born in Australia．

    Initially the couple thought they would complete their travels in four years, but now, they believe it could take seven more．

    "Since our belief is the need to respect nature, we travel only when conditions are good," Schworer said．

    Now many young people are traveling around the world on their own，not because they have no one to travel with，but because they prefer to go alone.

    Kristina Wegscheider from California first traveled alone when she was at college and believes that it is something everyone should do at least once in their life. ＂It opens up your mind to new things and pushes you out of your comfort zone.＂ Wegscheider has visited 46 countries covering all seven continents.

    In foreign countries，with no one to help you read a map，look after you if you get ill，or lend you money if your wallet is stolen，it is challenging. This is what drives young people to travel alone. It is seen as character building and a chance to prove that they can make it on their own.

    Chris Richardson decided to leave his sales job in Australia to go traveling last year. He set up a website，The Aussie Nomad，to document his adventures. He says he wished he had traveled alone earlier. ＂The people you meet，the places you visit，or the things you do，everything is up to you and it forces you to grow as a person，＂ said the 30-year-old man.

    Richardson describes traveling alone like ＂a shot in the arm＂，which ＂makes you a more confident person that is ready to deal with anything＂. He said，＂The feeling of having overcome something on my own is a major part of what drives me each day when I'm dealing with a difficult task. I walk around with my head up because I know deep down inside that nothing is impossible if you try.＂

    The great 19th century explorer John Muir once said，＂Only by going alone in silence can one truly get into the heart of the wilderness.＂

    My three-year-old granddaughter, Tegan, went with her parents to a family gathering at the home of her other grandparents. Everyone was having a wonderful time visiting and catching up on all the latest family news.

    Like most children, Tegan was having a good time playing with all the toys that were different from her own and that were kept for children to play with at her grandparents' house. In particular, Tegan had found a little tea set and had begun pretending that she was having a tea party. She set up all the place settings and arranged her table with the great care and elegance that only a three-year-old can create. Meanwhile, her Daddy concentrated on conversation, and as he continued to chat with his family, Tegan would hand him a cup of "tea". Her Daddy, who always tries to participate in her games, would pause for a few seconds from his conversation, and say all the proper words and gestures for her tea party which would thrill Tegan. He would request two lumps of sugar. He would tell her how wonderful her tea tasted, and then he would continue his adult conversation with his family.

    After going through this routine several times, her Daddy suddenly awoke to reality as he had a flash of concern in his mind: "She is only three years old, where is she getting this 'tea' that I've been dutifully drinking?" He quietly followed her, without her knowing, and his fears were growing stronger as he saw her turn and go through the bathroom door. Sure enough, there she was stretching up on her tippy toes reaching up to get her 'tea' water out of the container of water that grandpa used to soak (浸泡)his false teeth!

    We often just use our sense of sight, touch, smell, and taste to eat food. But what about our sense of hearing? Does sound also affect our dining experience?

    A new report answers, “yes, it does.”

    That answer comes from researchers at Brigham Young University and Colorado State University in the United States. They found that hearing is important in the eating experience.

    Hearing is often called “the forgotten food sense”, says Ryan Elder. Elder is an assistant professor of marketing at Brigham Young University's Marriott School of Management. He says that if people notice the sound the food makes as they eat it, they might eat less. On the other hand, watching loud television or listening to loud music while eating can hide such noises. And this could lead to overeating.

    For the study, the researchers wanted to test whether the sounds of eating—chewing, chomping and crunching—had any effect on how much a person ate. During the experiments, the test subjects wore headphones and listened to noise at either a high or low audio level. Then researchers gave them a crunchy snack: pretzels. The study found that subjects who listened to the higher volume noise ate more pretzels than those with the low audio levels.

    Elder says that when hiding I heard sounds of eating, like when you watch television or listen to loud music while eating, we take away the sense of hearing. And this may cause you to eat more than you would normally. The researchers are calling this, the “crunch effect”.

    The researchers admit that the effects may not seem like much at one meal. But over a week, a month or a year, all that food can really add up.

    Would it surprise you to learn that, like animals, trees communicate with each other and pass on their wealth to the next generation?

    UBC Professor Simard explains how trees are much more complex than most of us ever imagined. Although Charles Darwin thought that trees are competing for survival of the fittest, Simard shows just how wrong he was. In fact, the opposite is true: trees survive through their co-operation and support, passing around necessary nutrition (营养) “depending on who needs it”.

    Nitrogen (氮) and carbon are shared through miles of underground fungi (真菌) networks, making sure that all trees in the forest ecological system give and receive just the right amount to keep them all healthy. This hidden system works in a very similar way to the networks of neurons (神经元) in our brains, and when one tree is destroyed, it affects all.

    Simard talks about “mother trees”, usually the largest and oldest plants on which all other trees depend. She explains how dying trees pass on the wealth to the next generation, transporting important minerals to young trees so they may continue to grow. When humans cut down “mother trees” with no awareness of these highly complex “tree societies” or the networks on which they feed, we are reducing the chances of survival for the whole forest.

    “We didn't take any notice of it.” Simard says sadly. “Dying trees move nutrition into the young trees before dying, but we never give them chance.” If we could put across the message to the forestry industry, we could make a huge difference towards our environmental protection efforts for the future.