Using too much water or throwing rubbish into our rivers are clear ways that humans can put our water supply in danger , but we also affect our water supply in less obvious ways. You may wonder how paving(铺砌) a road can lead to less useable fresh water. A major part of the water we use every day is groundwater. Groundwater does not come from lakes or rivers. It comes from underground. The more roads and parking lots we pave ，the less water can flow into the ground to become groundwater.

    Human activity is not responsible for all water shortages(短缺). Drier climates are of course more likely to have droughts(干旱) than areas with more rainfall, but in any case, good management can help to make sure there is enough water to meet our basic needs.

    Thinking about the way we use water every day can make a big difference, too In the United States , a family of four can use 1.5 tons of water a day! This shows how much we depend on water to live, but there's a lot we can do to lower the number.

    You can take steps to save water in your home. To start with use the same glass for your drinking water all day. Wash it only once a day. Run your dishwasher (洗碗机)only when it is full 。Help your parents fix any leaks in your home. You can even help to keep our water supply clean by recycling batteries instead of throwing them away.

    One half of the brain remains on high alert during the first night of sleep in a new space.

    Over the course of three experiments on 35 young, healthy volunteers, researchers measured brain activity during two nights of sleep. They found that part of the left side of the brain remained more active than the right side only on the first night, specifically during a deep sleep stage.

    “When you sleep in a new place for the first time, a part of one side of the brain seems to stay awake, so you could wake up faster if necessary,” said senior study author Yuka Sasaki of Brown University.

    While this may be bad news for business travelers who regularly make brief overnight trips, it may not be as troublesome for people who go away for longer periods of time, Sasaki added by email.

    To see how being in a strange place affects sleep, Sasaki and colleagues performed a series of lab tests on their subjects.

    When they stimulated（刺激） the left side of the brain with sounds in the right ear during deep sleep on the first night, that led to greater possibility of waking and faster action upon waking, than if sounds were played in the left ear to affect the right side of the brain. On the second night, there wasn't any difference in reactions to tests between the left and right sides of the brain, even during deep sleep. This suggests that there is a first-night-only effect specifically in one side of the brain during deep sleep, the authors conclude.

    One limitation of the new study is its focus on healthy volunteers, which means the results may not apply to people with sleep disorders, the authors note.

    While it's possible that the findings may explain poor sleep among frequent travelers, the study wasn't designed to test whether these “first night effects” continue to happen to people every time they hit the road, said Patrick Finan, a researcher at Johns Hopkins University School of Medicine in Baltimore.

    I have never been a fan of the phrase, "No pains, no gains." I prefer the alternative version, "No pains, no pains!" When it comes to exercise, for example, I learned years ago that pushing through pain was more likely to lay me up with an aching back than to leave me feeling strong and healthy.

    But there are times when stressful situations actually do lead to greater happiness. A new study published in the Journal of Happiness Studies found that people who pursue (追求) goals that are tough to achieve feel more stress in the moment, but greater happiness in the aftermath particularly if they feel connected to others along the way.

    The researchers concluded that happiness increases when people develop greater competence in something and greater competence only comes when people keep on working through the stress-inducing phase of trying, fighting, and trying again to learn and grow. If the psychological needs to be autonomous or self-directed, and to be connected to others are met, the momentary stresses will be less acute, and the resulting happiness will be more lasting.

    This idea reminds me of another often quoted phrase, which I have heard in reference to challenging tasks, such as exercise —"Fill-in-the-blank-stressful-task is the worst thing to do, but the greatest thing to have done." In other words, suffering from the stress of an exercise class that leaves us feeling sweat-drenched shouldn't lead us to walk away from exercising. And if we can pass those stressful moments with a friend, colleague or family member who is trustworthy and supportive, all will be better.

    As I travel my positive path, I'm certainly not seeking out stress. But life will offer me plenty of it, whether I ask for it or not. My task is to choose wisely when and how to face it head-on, knowing that happiness awaits on the other side.

    You may probably meet most of the powerful graduation speakers, here who are well-known people in their fields. I think the schools couldn't have picked better speakers than them, because they set good examples, deeply inspiring us in our daily life.

    1) Steve Jobs, Stanford University:

    "Remembering you're going to die, and the best way I know is to avoid the trap of thinking that you have something to lose. There is no reason not to follow your heart. Your time is limited, so don't waste it living someone else's life. Don't let the noise of others' opinions drown out your own inner voice... "

    2) Oprah Winfrey, Stanford University:

    "I consider the world, this Earth, to be like a school... And the secret I've learned to get ahead is being open to the lessons from the grandest universe of all. Don't react against a bad situation. And the solution will arise from the challenge. So don't give up easily, acting with responsibility... "

    3) Bono, University of Pennsylvania:

    "For four years you've been buying, trading, and selling everything you've got in this market-place of ideas. Your pockets are full, even if your parents' are empty, and now you've got to figure out what to spend it on... The world is more flexible than you think and it's waiting for you to hammer it into shape... "

    4) Michael Dell, University of Texas at Austin:

    "Now it's time for you to move on to what's next and obtain your desire. But you must not let anything prevent you from taking those first steps. Don't spend so much time trying to choose the perfect opportunity, or sometimes you'll miss the right opportunity. Recognize that there will be failures and obstacles. But you will learn from your mistakes and the mistakes of others."

    The British Museum is a museum dedicated to human history, art and culture, located in the Bloomsbury area of London. Its permanent collection, numbering some 8 million works, is among the largest and most comprehensive in existence and originates from all continents, illustrating and documenting the story of human culture from its beginnings to the present.

    The British Museum was established in 1753, largely based on the collections of the physician and scientist Sir Hans Sloane. The museum first opened to the public on 15 January 1759 in Montagu House in Bloomsbury, on the site of the current museum building.

    Admission and opening times

    Free, open daily 10: 00—17: 30.

    The Museum is open every day except for 24, 25 and 26 December and 1 January.

    Museum galleries are open daily 10: 00—17: 30, and most are open until 20: 30 on Fridays.

    Closing starts from 17: 20 (20: 20 on Fridays).

    Tips for your school visit

    It's a good idea to come and see the Museum before your visit. Whatever your plans, please book in advance via the Ticket Desk to make sure you get the most out of your trip.

    Booking your visit

    Contact the Ticket Desk at ＋44(0)20 7323 8181 or tickets @ britishmuseum.org

    Cancellation

    If you are not able to attend a session you must inform the Ticket Desk at least three weeks before the session date. Failure to do so may incur a charge.

    Gallery availability

    Please book at least one term in advance and wait for confirmation before making travel plans. Greek and Egyptian galleries book up quickly. Opening times of some galleries may be limited at short notice—you will be contacted if necessary.

    Access and special educational needs

    The majority of galleries and all special exhibitions are fully accessible. There is a range of facilities for visual, hearing and mobility impaired students.

    Parking

    There is little on-street parking available. The nearest car park to the Museum is located at Bloomsbury Square, WC1A 2RJ. There is limited parking in the Museum's forecourt for disabled visitors only. To make arrangements please telephone＋44 (0)20 7323 8299 at least 24 hours in advance. You will be asked to provide the registration number, make and model of your vehicle and the date of your visit.

    Support us

    Your support is vital in enabling the Museum to fulfill its mission to share its collection with the world. The British Museum relies on funding from a wide range of sources and there are many ways that you can donate to help ensure the display, care and preservation of the collection for future generations.

    Please consider supporting the British Museum today.

The brain-training app trains people to tap on images of healthy foods but to stop when they see unhealthy snacks, creating a link between these foods and stops. The new study, by the universities of Exeter and Helsinki, found that playing the game about once a day for a month led to an average one-point reduction of junk food consumption.

Generally, people who used the app more also reported great changes in their food intake. One app user wrote, "Really useful. I used to eat junk food two to four times a week and I have reduced this to once a week after using the app regularly for a month. My desire for junk food has been reduced greatly and I no longer eat in the evening mindlessly."

The study used the app's usage data, and the app regularly asked questions about how often users eat certain food, along with other information such as their age and weight. The findings suggested that using the app regularly was linked with big changes in eating habits.

The app is free and it only takes about four minutes per day, so it's something people can do not just at home but at work and elsewhere. "From our results it seems important that you do the training at regular times and don't just stop. Therefore, keep it interesting, so you won't get bored with it. Personalize the app as much as possible and pick the food that you find really hard to resist," said Natalia Lawrence, a professor of the University of Exeter.

The researchers stressed that their findings should be further proved, because there was no comparison group and other factors____(such as the possibility that people who did more training were also more motivated to lose weight) could play a part in the results.