The need to feed a growing population is putting much pressure on the world's supply of water. With 97% of the world's water too salty to be drunk or used in agriculture, the worldwide supply of water needs careful management, especially in agriculture. Although the idea of a water shortage(短缺)seems strange to someone fortunate enough to live in a high rainfall country, many of the world's agricultural industries experience constant water shortages.

    Although dams can be built to store water for agricultural use in dry areas and dry seasons, the costs of water redistribution(重新分配)are very high. Not only is there the cost of the engineering itself, but there is also an environmental cost to be considered. Where valleys(山谷)are flooded to create dams, houses are lost and wildlife homes destroyed. Besides, water may flow easily through pipes to fields, but it cannot be transported from one side of the world to the other. Each country must therefore rely on the management of its own water to supply its farming requirements. This is particularly troubling for countries with agricultural industries in areas dependent on irrigation. In Texas, farmers' overuse of irrigation water has resulted in a 25% reduction of the water stores.

    In the Central Valley area of southwestern USA, a huge water engineering project provided water for farming in dry valleys, but much of the water use has been poorly managed.

    Saudi Arabia's attempts to grow wheat in desert areas have seen the pumping of huge quantities of irrigation water from underground reserves. Because there is no rainfall in these areas, such reserves can only decrease, and it is believed that fifty years of pumping will see them run dry.

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    A new research has discovered that meditation(冥想)and oxygen sport together reduce depression. The Rutgers University study found that this mind and body combination, done twice a week for only two months, reduced the symptoms of a group of students by 40 percent.

    “We are excited by the findings because we saw such a meaningful improvement in both clinically depressed and non-depressed students,” said lead author Dr. Brandon Alderman. “It is the first time that both of these two behavioral ways have been looked at together for dealing with depression.”

    Researchers believe the two activities have an interactive effect in combating depression. Alderman and Dr. Tracey Shors discovered that a combination of mental and physical training(MAP) enabled students with major depressive disorder not to let problems or negative thoughts defeat them.

    Rutgers researchers say those who participated in the study began with 30 minutes of focused attention meditation followed by 30 minutes of oxygen sport. They were told that if their thoughts drifted to the past or the future they should refocus on their breathing, which enabled those with depression to accept moment-to-moment changes in attention.

    Shors, who studies the production of new brain cells in the hippocampus—part of the brain involved in memory and learning—says scientists have shown in animal models that oxygen sport exercise keeps a large number of certain cells alive.

    The idea for the human intervention(干预)came from her laboratory studies, she says, with the main goal of helping individuals acquire new skills so that they can learn to recover from stressful life events.

    By learning to focus their attention and exercise, people who are fighting depression can acquire new learning skills that can help them process information and reduce the overwhelming recollection of memories from the past, Shors says.

    “We know these treatments can be practiced over a lifetime and that they will be affective in improving mental health,” said Alderman. “The good news is that this intervention can be practiced by anyone at any time and at no cost.”

    Visit one of the most outstanding prehistoric sites in the United Kingdom, and enjoy amazing historic English attractions. Please notice that every tour starts and ends in London. Have a tour with visiting Britain.

    Stonehenge Direct Tour

    Visit one of the most outstanding prehistoric sites in England and in the world: Stonehenge.

    Duration：1 day

    Price：Adults ￡29.99，Children ￡28.99

    Stonehenge and Bath Tour

    Enjoy a late breakfast before heading to the Stonehenge site and end your day with an original visit to the Roman Baths.

    Duration：10 hours(departure 10：30 a．m.，return 8：30 p．m.)

    Price：Adults ￡64，Children ￡60

    Stonehenge, Bath and Windsor Castle Tour

    Explore three of England's most popular sites to visit: Windsor Castle, Stonehenge and the Roman Baths.

    Duration：1 day(return 8：30 p．m.)

    Price：Adults ￡64.80, Children ￡61.20

    Stonehenge, Lacock and Bath Tour

    Come and feel the warmth of Bath, see the pleasant village of Lacock, and solve the mystery of Stonehenge.

    Duration：1 day(return 6 p．m.)

    Price：Adults ￡85，Children ￡78

    Stonehenge, Windsor and Oxford Tour

    Choose Stonehenge ，Windsor and Oxford Tour and enjoy ancient mysticism, royal history and illustrious knowledge.

    Duration：1 day

    Price：Adults ￡72, Children ￡68

    Stonehenge, Bath and Stratford Tour

    Take a tour to make the most of the English historic attractions：the Stonehenge site, Bath and Stratford, the birthplace of playwright William Shakespeare.

    Duration：1 day(return 8 p．m.)

    Price：Adults ￡79, Children ￡68

    Want a wonderful travel in London? Don't miss the following!

    Cartoon Museum

    This highly entertaining London tourist attraction covers the history and development of British cartoons from the 18th century to the present day. You can find a detailed collection of all types of cartoons in this museum including caricatures (讽刺漫画) and rare examples of cartoon art: it's an ideal place to entertain kids of all ages as well as a serious collection for animation enthusiasts.

    There are over nine hundred pieces on exhibit and the museum regularly holds events where both children and adults can participate. Booking for these events is recommended due to the popularity year round of this London Museum.

    Telephone: 020 7580 8155

    Chislehurst Caves

    Chislehurst in London is home to chalk caves that were mined by hand for over 8,000 years. A tour of these caves is an exciting way to see how British people have impacted on their environment over thousands of years.

    Telephone: 020 8467 3264

    The Old Operating Theatre Museum

    The Old Operating Theatre Museum is one London museum offering a fascinating insight into the medical profession of the past. This 300-year old herb garret (阁楼) is Britain's only surviving operating theatre, with a wooden operating table and an observation stand, from which visitors can witness surgery performed.

    Telephone: 020 7188 2679

    Curzon Mayfair Cinema Museum

    Recently voted one of London's best cinemas by Time Out readers, the Curzon Mayfair cinema is everything you would expect from this particular part of town: luxurious (奢华的) and tasteful. Showing mostly art-house and independent films, the Curzon Mayfair is unique in the world of London cinema for its role in screening these films for industry and press.

    Telephone: 033 3321 0104

    You know those nutrition guidelines the government issues every few years? It turns out that following them isn't just good for your health. It's good for the planet, too.

    " What we found is that impacts vary across nations, but in the high­impact nations, in general, you can see that, if you follow a nationally recommended diet, despite the fact that these diets don't mention explicitly—or most of them don't explicitly mention—environmental impacts, that you are going to have lower environmental impacts due to that. So that's sort of fairly clear across all the high­income nations." said Paul Behrens, an environmental scientist at Leiden University in the Netherlands.

    The food we eat takes a big toll on the environment. A third of the ice­free land on Earth is used for agriculture, and according to some estimates, producing food accounts for roughly a fifth of all human­caused greenhouse gas emissions. Fertilizer runoff also leads to other problems, like the algae blooms in Lake Eerie and the Dead Zone in the Gulf of Mexico.

    However, following dietary guidelines would reduce those impacts, especially in wealthy countries like the US. "Most of the reductions come from meat and dairy," which have an outsized impact on land use and pollution, and are a major source of greenhouse gases.(That's partly due to cow farts. Seriously.) Following the suggestions would also mean eating fewer calories, since many people here eat more than they need.

    Overall, in high­income countries, Behren's team estimates that following the rules could result in as much as a 17 percent reduction in land use, a 21 percent reduction in nutrient pollution, and a 25 percent drop in agricultural greenhouse gas emissions. Cutting down on how much food we waste—which is roughly a third in the US—could help even more. The results are in the Proceedings of the National Academy of Sciences.

    Of course, people are notoriously bad at following diets. But: "These nationally recommended guidelines do actually have a knock­on effect on other areas of policy making. So if I'm developing a new healthy­eating­for­schools program then that's going to be based off a lot of detail that I get from the nationally recommended guidelines. So while it might not necessarily be the case that people follow directly …they actually are quite influential on the preparation of other advice."

    It seems that a smaller environmental footprint and a healthier lifestyle could go hand in hand.

    The full moon climbs over the eastern horizon (地平线) and hangs like a huge orange globe in the sky. A few hours later, the moon is overhead but seems to have changed. The huge orange globe has become a small silver disk. What has happened? Why has the orange color disappeared? Why does the moon seem so much smaller and farther away now that it is overhead?

    The moon appears orange on the horizon because we view it through the dust of the atmosphere. The overhead moon does not really shrink (缩小) as it moves away from the horizon. Our eyes inform us that the overhead moon is farther away. But in this position the moon is actually closer to our eyes than when it is near the horizon.

    The change in size is a trick our eyes and minds play on us. When the moon is low in the sky, we can compare its size with familiar objects. It is easy to see that the moon is much larger than trees or buildings, for example. When the moon is high in the sky, however, it is hard to compare it with objects on earth. Compared to the vastness of the sky, the moon seems small.

    There is another reason why the moon seems to shrink. We are used to staring at objects straight ahead of us. When an object is difficult to see, our eyes have to try to focus on it. When we move our heads back to look up, we will try hard again. Looking at something from an unaccustomed position can fool you into believing an object is smaller or farther away than it is. However, scientists do not yet understand completely why the moon seems to shrink as it rises in the sky.