A warm drink of milk before bed has long been the best choice for those wanting a good night's sleep. But now a study has found it really does help people nod off-if it is milked from a cow at night.

    Researchers have discovered that “night milk” contains more melatonin(褪黑激素), which has been proven to help people feel sleepy and reduce anxiety.

    The study, by researchers from Seoul, South Korea, involved mice being fed with dried milk powder made from cows milked both during the day and at night.

    Those given night milk, which contained 10 times the amount of melatonin, were less active and less anxious than those fed with the milk collected during daytime, according to the study published in The Journal of Medicinal Food.

    Night milk quickened the start of sleep and caused the mice to sleep longer.

    While the effect of cows milk harvested at different time has not been tested on humans up to now, taking melatonin drugs has been suggested to those who are struggling to fall asleep at night.

    Previous studies have also indicated that milk can be excellent for helping sleep because of the calcium content, which helps people to relax.

    Milk is also sugar-free and additive-free with nutritionists recommending skimmed milk as the best choice before bed as it is the least fattening. The more fat you take in before bedtime, the greater burden you will put on your body at night.

    By the mid-nineteenth century, the term “icebox” had entered the American language, but ice was still only beginning to affect the diet of ordinary citizens in the United States. The ice trade grew with the growth of cities. Ice was used in hotels, pubs, and hospitals, and by some forward-looking city dealers in fresh meat, fresh fish, and butler. After the Civil War (1861-1865), as ice was used to refrigerate freight cars(货车), it also came into household use. Even before 1880, half the ice sold in New York, Philadelphia, and Baltimore, and one-third of that sold in Boston and Chicago, went to families for their own use. This had become possible because a new household convenience, the icebox, a precursor（前身）of the modem refrigerator, had been invented.

    Making an efficient icebox was not as easy as we might now suppose. In the early nineteenth century, the knowledge of the physics of heat, which was essential to a science of refrigeration, was undeveloped. The common belief that the best icebox was one that prevented the ice from melting was of course mistaken, for it was the melting of the ice that performed the cooling. Nevertheless, early efforts to economize ice included wrapping the ice in blankets, which kept the ice from doing its job. Not until near the end of the nineteenth century did inventors achieve the delicate balance of insulation(绝缘) and circulation needed for an efficient icebox.

    But as early as 1803, an intelligent Maryland farmer, Thomas Moore, had been on the right track. He owned a farm about twenty miles outside the city of Washington, for which the village of Georgetown was the market center. When he used an icebox of his own design to transport his butter to market, he found that customers would pass up the rapidly melting butter of his competitors to pay an extra price for his butter, still fresh and hard in neat, one-pound bricks. One advantage of his icebox, Moore explained, was that fanners would no longer have to travel to market at night in order to keep their produce cool.

    One morning, more than a hundred years ago, an American inventor called Elias Howe finally fell asleep. He had been working all night on the design of a sewing machine but he had run into a very difficult problem: It seemed impossible to get the thread to run smoothly around the needle.

    Though he was tired, Howe slept badly. He turned and turned. Then he had a dream. He dreamt that he had been caught by terrible savages whose king wanted to kill him and eat him unless he could build a perfect sewing machine. When he tried to do so, Howe ran into the same problem as before. The thread kept getting caught around the needle. The king flew into the cage and ordered his soldiers to kill Howe. They came up towards him with their spears raised. But suddenly the inventor noticed something. There was a hole in the tip of each spear. The inventor awoke from the dream, realizing that he had just found the answer to the problem. Instead of trying to get the thread to run around the needle, he should make it run through a small hole in the center of the needle. This was the simple idea that finally made Howe design and build the first really practised sewing machine.

    Elias Howes was not the only one in finding the answer to his problem in this way.

    Thomas Edison, the inventor of the electric light, said his best ideas came into him in dreams. So did the great physicist Albert Einstein. Charlotte Bronte also drew in her dreams in writing Jane Eyre.

    To know the value of dreams, you have to understand what happens when you are asleep. Even then, a part of your mind is still working. This unconscious(无意识的), but still active part understands your experiences and goes to work on the problems you have had during the day. It stores all sorts of information that you may have forgotten or never have really noticed. It is only when you fall asleep that this part of the brain can send messages to the part you use when you are awake. However, the unconscious part acts in a special way. It uses strange images which the conscious part may not understand at first. This is why dreams are sometimes called “secret messages to ourselves”.

    The U.S. has countless secret swimming holes throughout most states, many of which you've likely never heard of unless you're from the area.

    Allan Guei, 18, was a star basketball player at Compton High School in the Los Angeles area before he graduated last month. His good grades made him eligible for an unusual competition: A free-throw contest in the Compton High gymnasium. The top prize: ＄40,000 in scholarship money.

    Guei, whose parents immigrated to the United States from the Ivory Coast, knew how much that financial aid could mean for his family. He was also feeling a fair share of pressure as students and teachers crushed into the gym to watch Guei and seven other randomly compete against each other.

    Guei won the free-throw contest by one basket and netted the ＄40,000. But it's what he did next that's truly astonishing.

In the weeks following the March free-throw competition, Guei learned that he'd scored a full-ride basketball scholarship to California State University—Northridge. NCAA(全国大学生体育协会)rules allowed Guei to accept the athletic scholarship and also keep most of the ＄40,000 he had won.

    But Guei couldn't stop thinking about the seven talented runners-up from the free-throw contest. They, too, had dreams and very real needs. So, he asked Principal Jesse Jones to make a surprise announcement at Compton High's graduation ceremony: Geui wanted to donate the ＄40,000 to the other seven students.

    “I've already been blessed so much and I know we're living with a bad economy, so I know this money can really help my classmates,” Guei said in a statement. “It was the right decision.”

    Guei elaborated on his decision to give the money away in an interview with ESPN(体育电视网): “I was already well taken care of to go to school, to go to university for free… I felt like they needed it more than I did.”

The giant Amazon rainforest in South America has been a mystery for centuries. It holds all kinds of natural wonders. Among them in Colombia, a river stands out as"the most beautiful river"in the world. 

Locally called Carni o Cristales, this special river lies in a national park. It is made up of several waterfalls, rapids, and plenty of pools. For most of the year, Canio Cristales looks like a common river: clean, green, and rocky. However, during the short period between September and November, the river explodes(迸发) with life and colour. It appears as any mix of colours including blue, green, yellow, orange, and a purplish red. So it is also known as the"River of Five Colours". 

Although at first it may appear as if some chemicals were added to the water, this rainbow river is completely natural. Cafio Cristales'colours are the result of a rare(稀有) water plant which needs sunlight to grow. The plants change col-our depending on how much sunlight they receive, and the amount is decided by the height and speed of the water. Therefore, it is possible for the plants to be totally colourless if the sunlight is too hard to get. They are a delicate plant. This makes them easily damaged in the water. 

Actually, the river faces some problems, including drier seasons, wildlife trouble, waste management, and budget(预算) cuts. In 2007, the park was forced to close because it was over-crowded with tourists. Now the park admits only 200 people a day and requires them to mind their behaviour. 

Today, Cano Cristales still shines among Colombia's most popular natural attractions, drawing thousands of tourists every year.