The African elephant, the largest land animal remaining on earth , is of great importance to African ecosystem(生态系统). Unlike other animals, the African elephant is to a great extent the builder of its environment. As a big plant-eater, it largely shapes the forest-and-savanna(大草原)surroundings in which it lives, therefore setting the terms of existence for millions of other animals that live in its habitat(栖息地).

    It is the elephant's great desire for food that makes it a disturber of the environment and an important builder of its habitat. In its continuous search for the 300 pounds of plants it must have every day, it kills small trees and underbushes, and pulls branches off big trees. This results in numerous open spaces in both deep tropical forests and in the woodlands that cover part of the African savannas. In these open spaces are numerous plants in various stages of growth that attract a variety of other plant-eaters.

    Take the rain forests for example. In their natural state, the spreading branches overhead shut out sunlight and prevent the growth of plants on the forest floor. By pulling down trees and eating plants, elephants make open spaces, allowing new plants to grow on the forest floor. In such situations, the forests become suitable for large hoofed plant-eaters to move around and for small plant-eaters to get their food as well.

    What worries scientists now is that the African elephant has become an endangered species. If the elephant disappears, scientists say, many other animals will also disappear from vast areas of forest and savanna, greatly changing and worsening the whole ecosystem.

    Would you buy a car that released calming smells into the air when you are stuck in heavy traffic? Would you buy a robot that smells like a human being?

    Many people have seen the 3-D computer-made environments of virtual reality (VR). Now these virtual worlds will not just look and sound real. Researchers have created VR environments that even smell like the real things. With the new technology, users open a virtual door and step into a new environment, like a rainforest. After they enter this virtual world, special equipment releases forest-like smells into the air to make the experience seem more real.

    Suzanne Fisher-Murray said, “it is a really wonderful experience that you have because you're exploring this environment and you have smells with it.”

    In the United States, Smell-O-Vision was designed to provide smells during the showing of a movie. The Smell-0-Vision system was once popular in the 1960s. Now, Emanuela Maggioni says it is close to becoming popular again. “The connection with emotions, memories, and…the sense of smell,” Maggioni said. “It is unbelievable what we can do with technology.”

    The uses for smell technology are not just limited to films and the performing arts. Researchers showed a computer program where users could imagine themselves driving a car. The system included a special smell-spraying machine. Dmitrijs Dmitrenko said, “We want to deliver the smell of lavender（薰衣草）every time the person drives over the speed limit. We choose lavender because it's a very calming smell.”

    Scientists are experimenting with smell instead of sounds or image-based alerts on telecommunications equipment. And businesses are already using smell to influence people's behavior. “Not only.…in stores…But on the other side, you can create and stimulate immediate buying,” Maggioni said. “So you're in a library and you smell coffee and actually you are unconsciously having the need to drink a coffee.”

    When the natural climate changes due to global warming, it can surely affect seals. The majority of them live in the Antarctic region so as the ice is melting, their natural habitat（栖息地）can be seriously affected. These changes don't take place overnight. They can be the result of many years of additional temperatures in the area. The seals then have to find ways to adapt.

    Seals depend on the cool air currents to bring plenty of food for them. When the temperatures get higher, there is less and less food and the seal population starts to get depleted. Mothers aren't healthy enough to feed their babies. Many of them end up abandoned as the mothers have to leave to find their own source of food.

    The fact that their desire to produce young can be changed by the warmer temperatures is frightening too. It is also believed that the warmer temperatures can allow different diseases and viruses to attack the seals. This is a huge concern as they can rapidly wipe out huge numbers of seals out there.

    However, these changes in climate and temperature aren't all bad for other species of seals. Scientists have found that those living in warmer climates are producing more young due to the changes. Research also shows that the females are moving further to find food and water. When they are out of the reach of the governing males, they are more willing to accept the moves of other males in the group.

    This is good news too because it means that there will be more selection in the gene pool（基因库）for future generations. It can help the seals as a species adapt to changes in their natural environment more easily.

    The climate change problem for seals is directly linked to humans. When we take action to change what we let out into the environment, we will make positive changes for the seals. However, it is going to take a very long time to reverse（彻底改变）the effects of what has already been done.

    Try this: For an entire day, forget about the clock. Eat when you're hungry and sleep when you're tired. What do you think will happen?

    You may be surprised to find that your day is much like most other days. You'll probably get hungry when you normally eat and tired when you normally sleep. Even though you don't know what time it is, your body does. These patterns of daily life are called circadian rhythms(生理节奏), and they are more than just habits. Inside our bodies are several clocklike systems that follow a roughly 24-hour cycle. Throughout the day and night, our inner clocks direct changes in temperature, body chemicals, hunger, sleepiness and more.

    Everyone's rhythms are different, which is why you might like to stay up late while your sister always wants to go to bed early. But on the whole, everyone is programmed to feel tired at night and energetic during the day. Learning about our body clocks may help scientists understand why problems arise when we act out of step with our circadian rhythms. For example, traveling across time zones can make people wake up in the middle of the night. Regularly staying up late can make kids do worse in tests.

    "There is a growing sense that when we eat and when we sleep are important parts of how healthy we are," says Steven Shea, director of the Sleep Disorders Program at Brigham and Women's Hospital in Boston.

    One way to learn about how our body clocks tick is to mess them up and see what happens. That's what neurologist(神经病学家)Frank Scheer and his workmates did in a recent study. Staying up night after night, their studies suggest, could make kids extra hungry and more likely to gain weight. And regularly sleeping too little, Scheer says, may be one cause of the recent increase in childhood obesity.

    In my memory, winters always used to be really unpleasant. You had to dress like a bear just to keep warm when you went outside. You were often cold, wet and no more than one step away from the thin ice on the lake. If you worked over time and went home in the dark, you would arrive home to an ice-cold house. And that would mean turning on the heating and waiting.

    Fortunately, things don't have to be so challenging any more. Technology, engineering and design have developed, giving us new solutions to old problems. It means dealing with winter needn't be like skating on thin ice.

    With a smart thermostat(恒温器), our homes can be toasty when we need them to be. Many models go with smartphone APPs that allow you to regulate temperature from a distance, so we can warm up the house before we arrive home. According to techradar.com, a large technology news and reviews website, Tado's model has a voice control function, while the Nest “learns” your habits and heats the house for you.

    Clothes have been given an upgrade, too. Electronic heated jackets and trousers heat up when you turn them on. What better way to keep warm in the dead of winter? At the touch of a button, or through an APP on our phones, the clothes produce heat from materials placed inside. Many models offer three levels of heating which stay warm for over 12 hours.

    Finally, there is the headgear(头部装备) - Hats that have speakers which are included in the cloth using Bluetooth technology, so we can listen to our favourite music or, in some cases, have a phone call using the in-built microphone. All while keeping the head warm and avoiding coldness.

    For many, the thought of winter used to be enough to make their blood run cold. But using technology, life needn't freeze up. There's no reason why winter can't be really, really cool.

    Many people find that music lifts their spirits. Now a new research shows that music therapy (疗法) can be a useful treatment for depression.

    The finding that music therapy offers a real medical benefit to depression sufferers comes from a review by the Cochrane Collaboration, a non-profit group that reviews health care issues. Some studies looked at the effects of providing music therapy to patients who were receiving drug treatment for depression. Others compared music therapy to traditional talk therapy. In four out of five of the trials, music therapy worked better at easing depression symptoms than therapies that did not employ music, the researchers found.

    “While the evidence came from a few small studies, it suggests that this is an area that is well worth further investigation.” said lead author Anna Maratos. Ms. Maratos notes that music therapy might be particularly useful for adolescents who may reject a traditional form of counseling. Some older patients also may not be comfortable talking about their feelings but do tend to express themselves through songs.

    There are two main types of music therapy. Sometimes, a therapist will listen to music with a patient and talk about the feelings or memories that it arouses. In another form, the therapist is a skilled musician and will improvise (即兴创作) music with the patient. If the patient doesn't play an instrument, he or she might be given a simple percussion (击打) instrument and the therapist will play along.

    Other studies have shown a benefit from music therapy in the treatment for dementia, learning disabilities, strokes and pain management during labor and birth. The problem is that there isn't very much high-quality research. "It doesn't easily attract serious research funding. It's difficult to do high-quality, large-scale trials." said Ms. Maratos.