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, 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 internal clocks direct changes in temperature, body chemicals, hunger, sleepiness and more.

    Everyone's rhythms are unique, which is why you might like to stay up late while your sister always wants to go to bed early. But overall, everyone is programmed to feel tired at night and energetic during the day.

    Scientists have known for a long time that the light of day and the dark of night play important roles in setting our internal（内部的） clocks. Now, new discoveries are giving scientists insights into how these clocks work.

    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 on tests and quizzes. And working shifts at night leads to higher rates of heart disease, diabetes and obesity.

    “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 Research Program at Brigham and Women's Hospital in Boston.

    Scientists still aren't sure why the timing of sleep matters so much, Shea says. But research findings suggest that our circadian rhythms are more important than we give them credit for.

    “During the night, we are prepared to sleep,” Shea says. “During the day, we are prepared to eat and move around. If you reverse (颠倒)what you are doing, everything is out of phase. That can have unfavorable consequences.”

    Max Vernon Mathews has been called the father of computer music. He created electronic tools so that people could use computers as musical instruments. He had a huge influence on the development of electronic music and how it is written, recorded and played.

    In 1957, Max Mathews wrote the first computer program that enabled a computer to create sound and play it back. At the time, he was working as an engineer at Bell Laboratories in New Jersey. His computer program was called Music. It enabled a large IBM computer to play a seventeen-second piece of music that he had written.

    The computer was so slow that it would have taken an hour to play the piece of music in seventeen seconds. For that reason, Mathews moved the work to a tape player, which could be sped up to play the music at a normal speed. He later said that the sound quality of the music notes was not great, but the technical importance of the music was huge.

    The science fiction writer Arthur C. Clarke visited Bell Laboratories in the 1960s. He heard a computer “sing” the song "Daisy Bell" on devices and programs developed by Max Mathews andother engineers. Clarke noted this technology in his book “2001: A Space Odyssey,” which was later made into a movie.

    Mathews continued creating other versions of the Music program. He became interested in how computers could help musicians outside recording studios.

    Max Mathews had a long and productive career. He worked with composers like John Cage and Edgard Varese. He helped create a center for research in computer music in Paris. And he taught at the Center for Computer Research in Music and Acoustics in Stanford University in California.

    Mathews believed modern musicians were not making full use of the power of computer music. He said a violin always sounds like a violin, but with a computer, the way a violin sounds is unlimited. He said he did not want computer sounds to replace live music. But he said he hoped laptop computers would one day be considered serious instruments

    Sheffield

    Lincoln College of English

    Classes for foreign students at all levels.

    3 months, 6 months, 9 months and one year course.

    Open all year.

    Small class (at most 12 students).

    Library, language laboratory and listening center.

    Accommodation (住宿) with selected families.

    25 minutes from London.

    Course fees for English for one year are ￡ 1,380 with reduction for shorter periods of study.

Both humans and animals have enemies. 11 is easy for us to know the difference between our friends and our enemies. But can other animals do the same? Elephants can! They can use their sense of vision and smell to tell the difference between people who mean a threat and those who do not. In Kenya, researchers find that elephants react differently to clothing worn by men of the Maasai and Kamba ethnic groups. Young Maasai men hunt animals and thus mean a threat to elephants; Kamba men are mainly farmers and are not a danger to elephants.

In an experiment conducted by animal scientists, elephants were first presented with clean clothing or clothing that had been worn for five days by either a Maasai or a Kamba man. When the elephants noticed the smell of clothing worn by a Maasai man, they moved away from the smell faster and took longer to relax than when they noticed the smells of either clean clothing or clothing worn by a Kamba man.

Clothing color also plays a role. In the same study, when the elephants saw red clothing not worn before, they reacted angrily, as red is typically worn by Maasai men. Rather than running away as they did with the smell, the elephants acted angrily toward the red clothing.

The researchers believe that the elephants' emotional reactions arc due to their different senses of smell and sight. Smelling a possible danger means that a threat is nearby and the best thing to do is run away and hide. Seeing a potential threat without its smell means that risk is low. Therefore, instead of showing fear and running away, the elephants express their anger and become aggressive.

    Alison Malmon was trapping up (完成) the end of her freshman year at the University of Pennsylvania, US when she got the news: Her older brother Brian, a student at Columbia University, was suffering from mental illness.

    Inspired by this, Malmon formed a group at her university to empower (使能够) students to talk openly about mental health. It soon blossomed into a national organization that today has more than 450 campus chapters. Leaders with the organization spend their time talking with college students about the pressure that today's young people face.

    "What you hear often is just a need to be perfect," said Malmon, "and a need to present oneself as perfect."

    And a new study in the UK proved that this need for perfectionism is simply part of today's society. In the study, two researchers studied more than 40,000 students from the US, Canada, and the UK. They found that what they called "socially prescribed(社会定向型的) perfectionism" increased by a third between 1989 and 2016.

    Lead researcher Thomas Curran said that while so many of today's young people try to present a perfect appearance online, social media isn't the only reason behind this trend. Instead, he said, it may be driven by competition in modern society, meaning young people can't avoid being sorted and ranked in both education and employment. That comes from new norms(准则) like greater numbers of college students, standardized testing and parenting that increasingly emphasizes success in education.

    For example, in 1976, half of high school seniors expected to get a college degree of some kind. By 2008, more than 80 percent expected the same. The researchers also said changes in parenting styles over the last two decades might have had an impact. As parents feel increased pressure to raise successful children, they in turn pass their "achievement anxieties" onto their kids through "excessive(过多的) involvement in their child's routines, activities or emotions"

    Those in the mental health community like Malmon say they're concerned about the impact the culture of perfectionism has on mental health on campuses. "Mental health has truly become this generation's social justice issue," she said. "It's our job to equip them with the tools and to let people know that it's not their fault."

Every four or five years, vast quantities of warm water build up along the west coast of South America. This phenomenon, El Nino, creates storms that cause destructive floods. The result is costly.

Modern farmers come to terms with El Nino. They use money saved in good years to rebuild in bad ones. But history suggests it need not be like that. In a paper published recently, Ari Caramanica, an archaeologist at University of the Pacific, in Lima, shows how it used to be done. And the answer seems to be, "better".

Dr Caramanica and her colleagues have been studying the Pampa de Mocan, a coastal desert plain in northern Peru. Pampa de Mocan is not suitable for farming. Its soil contains little organic matter and the annual rainfall in non-Nino years is usually less than two centimeters. Today's farmers therefore depend on canals to carry water from local rivers to their fields.

It had been assumed that ancient farmers had a similar arrangement — and so they did. But Dr Caramanica also found eight canals that could carry water far beyond the range of modern farms. She thinks that they were intended to guide the floodwaters arriving during Nino years. Around a quarter of the ancient agricultural infrastructure of this area seems to have been built only for managing Nino-generated floodwaters.

Evidence from pollen supports this theory, revealing that Pampa de Mocan produced lots of crops in some years, while remaining nearly barren in others. The team also uncovered two cisterns in the area serviced by the extended canals. These, probably, were used to store extra flood-water.

These findings suggest that, rather than resisting El Nino, early farmers in Pampa de Mocan were ready to make use of it when it arrived. Modern farmers might do well to learn from them.