It is reported that conservation groups in North America have been arguing about the benefits and dangers of wolves. Some groups believe wolves should be killed. Other people believe wolves must be protected so that they will not disappear from the wilderness(荒野).

For Killing Wolves

    In Alaska，the wolf almost disappeared a few years ago，because hunters were killing hundreds of them for sport. However, 1aws were established to protect the wolves from sportsmen and people who catch the animals for their fur．So the wolf population has greatly increased. Now there are so many wolves that they are destroying their own food supply.

    A wolf naturally eats animals in the deer family. People in the wilderness also hunt deer for food. Many of the animals have been destroyed by the very cold winters recently and by changes in the wilderness plant life．When the deer can't find enough food，they die.

    If the wolves continue to kill large numbers of deer, their prey(猎物) will disappear some day. And the wolves will, too. So we must change the cycle of life in the wilderness to balance the ecology. If we killed more wolves, we would save them and their prey from dying out. We'd also save some farm animals.

    In another northern state, wolves attack cows and chickens for food. Farmers want the government to send biologists to study the problem. They believe it necessary to kill wolves in some areas and to protect them in places where there is a small wolf population．

Against Killing Wolves

    If you had lived long ago，you would have heard many different stories about the dangerous wolf．According to most stories，hungry wolves often kill people for food．Even today，the stories of the “big bad wolf” will not disappear．

    But the fact is wolves are afraid of people, and they seldom travel in areas where there is a human smell．When wolves eat other animals，they usually kill the very young, or the sick and injured. The strongest survive. No kind of animal would have survived through the centuries if the weak members had lived. And has always been a law of nature.

    Although some people say it is good sense to kill wolves，we say it is nonsense! Researchers have found wolves and their prey living in balance．The wolves keep the deer population from becoming too large, and that keeps a balance in the wilderness plant life.

    The real problem is that the areas where wolves can live are being used by people. Even if wilderness land is not used directly for human needs, the wolves can't always find enough food. So they travel to the nearest source, which is often a farm. Then there is danger. The “big bad wolf” has arrived! And everyone knows what happens next.

    Throughout the past few years, I have tried to give myself to others. I have bounced around to find where I truly fit in. I found my place while I stayed in Guatemala, an orphanage(孤儿院), with the children living there. Through hearing many stories of their lives, I was moved to tears and started question my living ways and gave up everything that wasn't essential: makeup and any other sort of luxury(奢侈品). I lived like they did. It was the most relaxing feeling in the world.

    When at Nuestros Pequenos Hermanos, we were given the task of creating a pig pen. At first, I thought it should be easy. After arriving at the area where the pig pen should be, we saw a hill. We were told to uproot the weeds as well as level the entire area. Looking at it, we felt 'it would be impossible. On my own faith journey, I have felt this type of doubt before. The “hole”, as we referred to, is a symbol of my faith journey. It appeared to be an obstacle I could not overcome, but in the end I completed it with efforts. I feel this pig pen wasn't easy to create but was so rewarding to give.

    I've always struggled to be on a journey of faith, but I've never completely stepped foot onto the path until Guatemala. I've always tried to open my heart to everyone around me and give them my love. I feel as though I cut open my heart and share every bit of love 'I had with these orphans. There is one orphan named Ceto who will always remain very close to my heart. In Guatemala, I sponsor with thirty dollars a month, but it doesn't seem enough. I'll return there next summer and give more of my love for a whole month.

    When it was time to leave, I looked out of the window and saw not just ordinary children. Overall, the most significant accomplishment I made in Guatemala was stepping towards my own faith journey and not looking back.

    In a foreign country, a man visited a local restaurant. He didn't speak their language. He ordered something indecipherable off the menu. When the waiter brought him a plate of delicious looking fried noodles, he smiled and made an OK sign at the waiter with his thumb and forefinger linked in a circle. Looking angry, the waiter then picked up the dish and thrown it to his lap. What he did wrong, he wondered. Well, nothing is quite as it seems when it comes to using hand gesture in another country.

    Gestures have been used to replace words in many countries, and they are often specific to a given culture. Gesture may mean something complimentary in one culture, but is highly offensive in another.

    The gesture “thumb-up” is commonly misinterpreted. In English, it is popularly known as 'thumbs up', despite the fact that the action is commonly performed with only one hand. English-speaking Caucasians use it to signal 'OK', which is the same meaning as O.K. ring gesture. The two can in fact be used almost interchangeably.

    Avoid using this gesture in Southern Sardina or Northern Greece unless you want to invite a fight. While American, British and Australian would use the thumb up to signal hitch-hiking to the drivers, this message will not encourage a Greek driver or motorist to stop to give them a ride.

    There are no right or wrong signals, only cultural differences. Lack of cultural understanding will lead to disharmony among people from different cultures. When we know what to look for, such encounters with other cultures are actually very interesting, fascinating and fun. It is certainty a great topic to discuss over a cup of coffee and cakes.

    Can exercise during childhood protect you against memory loss many decades later?Exercise early in life seems to have lifelong benefits for the brain,in rats at least.

    "This is an animal study,but it shows that physical activity at a young age is very important一not just for physical development,but for the whole lifelong track of cognitive（认知的）development during ageing,"says Martin Wojtowicz of the University of Toronto,Canada."In humans,it may delay the appearance of Alzheimer's symptoms（阿兹海默氏症）,possibly to the point of preventing them."

    Wojtowicz's team divided 80 young male rats into two equal groups,and placed running wheels in the cages of one group for a period of six weeks.Around four months later—when the rats had reached middle age—the team taught all the rats to connect an electric shock with being in a specific box.When placed in the box,they froze with fear.

    Two weeks later,the team tested the rats in three situations: exactly the same box in the same room,the same box with the room arranged differently,and a completely different box in a different room.

    The rats without access to a running wheel when they were young now froze the same percentage of times in each of these situations,suggesting they couldn't remember which one was dangerous.But those that had been able to run in their youth froze 40 to 50 percent less in both changed box settings.

    “The results suggest the amount of physical activity when we're young,at least for rats,has influence on brain and cognitive health—in the form of better memories—when we're older,"says Arthur Kramer of Northeastern University in Boston,who has found that,in humans,exercise promotes the growth of new brain cells.

    Why can some people sleep through noises like a honking car or flushing toilet, while others are awakened by the lightest sound?

    To find the answer, sleep researchers at Massachusetts General Hospital conducted an unusual study of 12 self-described deep sleepers. After tests confirmed that the healthy volunteers were solid sleepers, they took part in a three-night study in the university's sleep laboratory. The participants spent the night in a big and comfortable room. But the room also included four speakers positioned near the top of the bed.

    During the night, the deep sleepers were subjected to 14 different recorded sounds, like street traffic, toilets flushing, and an airplane flying overhead. Next door, the researchers monitored their sleep patterns and brain waves.

    As expected, all of the participants slept relatively well, but there were differences in how they responded to the noisy interruptions. Some of the sleepers didn't wake up even when a sound was blasted at 70 decibels（分贝）; others were awakened by sounds at 40 or 50 decibels.

    The researchers discovered that the difference in a sleeper's reaction to noise could be predicted by the level of brain activity called "sleep spindles（纺锤体）". A sleep spindle is a burst of high-frequency brain activity coming from deep inside the brain during sleep. The source of the spindles is the thalamus（丘脑）, a part of the brain that sends sensory information to the rest of the cortex（皮层）.

    Before the study, the Massachusetts researchers theorized that the spindles are the brain's way of preventing sensory information from passing through the thalamus and waking the rest of the brain during sleep. They found that sleepers who experienced the most sleep spindles during the night were also the soundest sleepers and were least likely to be awakened by noise.

    Scientists already know that most people become lighter sleepers with age, most likely because older people experience less "slow wave sleep", which is the deepest stage of sleep. People also produce fewer sleep spindles as they age. But even when controlling for the stage of sleep a person was in, the number of sleep spindles still predicted their risk for awakening because of noise.

    More research is needed, but the findings suggest that a better understanding of sleep spindles could lead to new behavioral or drug therapies for people with sleep disorders. For example, future studies may try to determine whether diet, exercise or other behaviors may influence the number of sleep spindles a person produces during the night.

    Tourism is often about seeking deeper emotional and personal connections with the world around us. Not all travel experiences, however, need to take place in the real world. With the evolution of virtual reality (VR) technology, tourism will increasingly become a combination of physical and virtual worlds. VR may even remove the need to travel entirely.

    But can a VR experience really equal a real world one? Many experts believe it can. Studies have shown that our brains have an inbuilt VR-like mechanism that enables us to live imagined experiences. Much of our waking life is spent thinking about either the past or the future. This is known as" mind wandering". During these events we're not paying attention to the current world around us. Instead, we're recalling memories, or creating and processing imagined futures.

    When engaged in mind wandering, our brains process these mental images using the same pathways used to receive inputs from the real world. So, the imagined past or future can create emotions and feelings similar to how we react to everyday life. VR can create these same feelings.

    While critics might argue that a virtual experience will never match reality, there are several ways VR tourism could make a positive contribution. Firstly it could help protect sensitive locations from over-tourism. In recent years famous sites such as Maya Bay in Thailand, and Cambodia's Angkor Wat Temples have had to limit the number of visitors because of their negative impact. These places are now producing their own VR experiences that will allow tourists to pass through virtual models of the sites.

    Virtual reality may also allow people back in time, to experience historical events, visit ancient cities, and even to walk among dinosaurs.

    Finally, in a world where many people suffer from stress and depression due to overwork, virtual tourism may provide a cheap and convenient way for people to take brief holidays to otherwise unreachable destinations and recharge their batteries, without ever leaving their homes.

    It sounds like science fiction but it's already happening. As virtual technology improves and as people continue to demand new and interesting experiences, expect more virtual tourism, both in combination with the real world and instead of it.