Our body clock, or natural body rhythm, influences our energy and alertness. Paying attention to it can help us choose the suitable time of the day when we best perform specific tasks.

    The reality, however, is that most of us organize the time around work demands, school deadlines, commuting or social events. Doing whatever the body feels like doing is a luxury in today's fast-paced modern society.

    But that doesn't mean it isn't worth trying. Obeying our body clock has significant health benefits. Disrupting our natural body rhythm, on the other hand, has been linked to problems such as depression, obesity, or headache, says Steve Key, a biology professor.

    When the body clock can synchronize (使…同步) the rhythms of its natural processes, it “gives us an advantage in daily life”, says Key.

    According to him, when it comes to cognitive (认知的) work, most adults perform best in the late morning. As our body temperature starts to rise just before awakening in the morning and continues to increase until midday, our memory, alertness and concentration gradually improve.

    However, he adds, our ability to concentrate typically starts to decrease soon thereafter. Most of us are more easily distracted (分心) between noon and 4 pm.

    Alertness also tends to fall after eating a meal and sleepiness tends to peak around 2 pm, making that a good time for a nap.

    Surprisingly, tiredness may increase our creative powers. For most adults, problems that require open-ended thinking are often best dealt with in the evening when they are tired, according to a study in the journal Thinking & Reasoning.

    When choosing a time of the day to exercise, paying attention to your body clock can improve results. Physical performance is usually best from about 3 to 6 pm, says Michael Smolensky, a professor of biomedical engineering.

    Of course, not everyone's body clock is the same, making it even harder to synchronize natural rhythms with daily plans.

Wilderness

    “In wilderness(荒野) is the preservation of the world.” This is a famous saying from a writer regarded as one of the fathers of environmentalism. The frequency with which it is borrowed mirrors a heated debate on environmental protection: whether to place wilderness at the heart of what is to be preserved.  

     As John Sauven of Greenpeace UK points out, there is a strong appeal in images of the wild, the untouched; more than anything else, they speak of the nature that many people value most dearly. The urge to leave the subject of such images untouched is strong, and the danger exploitation(开发) brings to such landscapes(景观) is real. Some of these wildernesses also perform functions that humans need—the rainforests, for example, store carbon in vast quantities. To Mr.Sauven, these ”ecosystem services” far outweigh the gains from exploitation.

    Lee Lane, a visiting fellow at the Hudson Institute, takes the opposing view. He acknowledges that wildernesses do provide useful services, such as water conservation. But that is not, he argues, a reason to avoid all human presence, or indeed commercial and industrial exploitation. There are ever more people on the Earth, and they reasonably and rightfully want to have better lives, rather than merely struggle for survival. While the ways of using resources have improved, there is still a growing need for raw materials, and some wildernesses contain them in abundance. If they can be tapped without reducing the services those wildernesses provide, the argument goes, there is no further reason not to do so. Being untouched is not, in itself, a characteristic worth valuing above all others.

    I look forwards to seeing these views taken further, and to their being challenged by the other participants. One challenge that suggests itself to me is that both cases need to take on the question of spiritual value a little more directly. And there is a practical question as to whether wildernesses can be exploited without harm.

    This is a topic that calls for not only free expression of feelings, but also the guidance of reason. What position wilderness should enjoy in the preservation of the world obviously deserves much more serious thinking.

    Mark is always engaged in his work. But this time he felt that it was time for him to take part in his community, so he went to the neighborhood meeting after work. The area city council woman was leading a discussion about how the quality of life was on the decline. The neighborhood faced many problems. Mark looked at the charts taped to the walls. There were charts for parking problems, crime, and for problems in empty buildings. Mark read from the charts, “Police patrols cut back, illegal parking up 20%”. People were supposed to suggest solutions to the council woman. It was too much for Mark. “The problems are too big”, he thought. He turned to the man next to him and said, “I think this is a waste of my time. Nothing I can do would make a difference here.”

    As he neared the bus stop on his way home, Mark saw a woman carrying a grocery bag, and a baby. As Mark got closer, her other child, a little boy, suddenly ran into the street. The woman tried to reach for him, but as she moved, her bag shifted, and groceries started to fall out. Mark ran to take the boy's arm and led him back to his mother. “You gotta stay with mom,” he said. Then he picked up the stray groceries while and the woman smiled in relief. “Thanks,” she said, “You've got great timing.” “Just being neighborly,” Mark said. As he rode home, he glanced at the walls of bus. On one of them was “Small acts of kindness add up.” Mark smiled and thought, “Maybe that's a good place to start.”

    Parents can cut the chances of their children getting fat simply by keeping them longer at table. Just three minutes extra at a family mealtime could help prevent child obesity. Research found that among poor families, the extra minutes at mealtimes made great improvement of a normal weight for the youth. The factors are likely to be communication and the importance of a scheduled mealtime.

    Dr Barbara Fiese said, “Children, whose families have a 20-minute meal over four times a week, weigh less than kids who leave the table after 15 to 17 minutes. Over time, those extra minutes per meal add up and become really powerful.”

    The researchers studied 200 family mealtimes, testing the effects of factors and mealtime behavior of families with children in primary school. They found that families, who said that shared mealtimes were an important part of family life and had special meaning for them, were less likely to have an obese child. Similarly, families, who talked more together and interacted more positively during the meal, were more likely to have healthy-weight children.

    Teaching low-income families how to make the most of family mealtimes was a wise idea. Dr Fiese said, “This is something we can target and teach.” She added, “It's also important to recognize the increasing differences of families and their sometimes complex living arrangements that may challenge their abilities to plan ahead and arrange a single time to communicate with each other.”

    Families in poorer US neighborhoods faced a lot of problems, including poor access to healthy food. But even so, regular high quality family mealtimes made a difference to the children's weight. Dr Fiese said, “Three to four extra minutes per meal will make a healthy weight more possible.”

    On December 26, 2004, hundreds of tourists relaxed on Sri Lanka's Yala National Park's beaches. But at mid-morning the park's elephants began crying wildly and running away from the ocean and up a nearby hill. The puzzled keepers could tell the animals were worried about something but what?

    What the keepers did not know was that a 30-foot wall of water was headed straight toward them. This tsunami(海啸) had been caused by an earthquake more than 1, 000 miles away in the Indian Ocean. When the huge wave hit the coast, it caused severe damage. Many people died. The elephants, however, were not swept away by the water. They stood safely on the hill.

    Scientists have long suspected that animals sense natural disasters before humans do. People have told stories of dogs refusing to go outside and sharks swimming to deeper waters before a hurricane. After the 2004 tsunami, people said they saw tigers, monkeys, and water buffalo escaping to higher ground before the waters rushed in. Even in the hardest-hit areas of southern Asia, there were few animal deaths.

    It's unlikely that an animal's so-called sixth sense comes from some magical power to see into the future. Experts believe that animals may be more sensitive than humans to changes in temperature and other environmental conditions that take place before a natural disaster. The elephants in Sri Lanka, for example, may have picked up vibrations from within the Earth, a sign that earthquake was coming. Because vibrations in the ground travel much faster than an ocean wave, the elephants may have felt the earthquake that caused the tsunami well before the tsunami itself came to the coast.

    A few scientists are calling for a system to track reports of strange behavior in people's pets, hoping that these reports can serve as a warning system that a natural disaster is about to happen. But Marina Haynes, an animal behavior scientist at the Philadelphia Zoo, says, "It would be an unreliable way to predict disasters. It can be difficult to know what an animal is doing. Is the animal nervous because an earthquake is about to happen or is it frightened because there is an enemy nearby?"

    Close your eyes for a minute and imagine what life would be like if you had a hundred dollars less. Also imagine what it would be like spending the rest of your life with your eyes closed. Imagine having to read this page, not with your eyes but with your finger-tips.

    With existing medical knowledge and skills, two-thirds of the world's 42 million, blind should not have to suffer. Unfortunately, rich countries possess most of this knowledge, while developing countries do not.

    ORBIS is an international non-profit organization which operates the world's only flying teaching eye hospital. ORBIS intends to help fight blindness worldwide. Inside a DC-8 aircraft, there is a fully-equipped teaching hospital with television studio and classroom. Doctors are taught the latest techniques of bringing sight back to people there. Project ORBIS also aims at promoting peaceful cooperation among countries.

    ORBIS tries to help developing countries by providing training during three-week medical programs. ORBIS has taught sight-saving techniques to over 3,000 doctors and nurses, who continue to cure tens of thousands of blind people every year. ORBIS has conducted 17 plan programs in China so far. For the seven to ten million blind in China ORBIS is planning to do more for them. At the moment an ORBIS is working on a long-term plan to develop a training center and to provide eye care service to Shanxi Province. ORBIS needs your help to continue their work and free people from blindness.

    For just US$38, you can help one person see; for $380 you can bring sight to 10 people; $1,300 helps teach a doctor new skills; and for $13,000 you can provide a training program for a group of doctors who can make thousands of blind people see again. Your money can open their eyes to the world. Please help ORBIS improve the quality of life for so many people less fortunate than ourselves.