Renaissance is a French word. It means “rebirth”. It's a strange name for a period of history. What was exactly “ reborn” during the Renaissance?

    To answer this question, we need to look back at the time of the Roman Empire. At this time Roman artists, scientists and writers influenced by Greek ideas were the world's most advanced. They had become skilled observers of the natural world around them, and had become experts in studying animals, plants, the human body or the stars and planets. They wrote down their ideas about what they saw, and based their theories about the world on their observations.

    During the fourth and fifth centuries the Roman Empire slowly broke down. Many of the Romans' art and sculptures were destroyed and some manuscripts（原稿）were lost as well. But most importantly, some of the ancient attitudes were lost. A questioning approach to the world was replaced by an unquestioning one.

    Why did this happen? One reason was to do with the influence of the Christian Church. Through the thousand years following the fall of the Roman Empire, the Church controlled many aspects of life including education and learning. The Church ran all the universities and thought that the aim of a university should be to teach old ideas more clearly, not to introduce new ones. The scholars in the universities were expected to study God and heaven from the Bible and ancient books, rather than the world around them.

Take medicine for example. The main textbook for doctors had been written by a Greek doctor called Galen more than a thousand years earlier. But when Roger Bacon, a thirteenth-century priest（牧师）, said that a new approach to medicine was needed — doctors should do their own original research instead of reading writers from the past such as Galen-the Church put him in prison.

    By the time of the fourteenth century, however, some parts of the Christian Church were becoming less strict about their ideas and there was a new state of mind among artists, doctors and scientist. People wanted to find out more about the world by studying it. This attitude of investigation had been common in classical scholars, and it was ‘reborn' during the Renaissance.

    Does stress cause gray hair? Many people believe that tension and stress can cause your hair to lose its color. In fact, it is an old-wives' tale that being upset all the time can result in premature graying. Here is a closer look at this situation and why some believe that this old wives' tale could be true.

    As one ages, the hairs on the head also age. In fact, just about everything on the human body begins to show signs of wear and tear (磨损) after a while. The joints wear and become stiff and skin wears and becomes wrinkled. Hairs on the head grow and eventually die. They are replaced, but in the process something else happens.

    When new hairs are replacing the old ones, the color or pigment (色素) is also added to them. However, as one ages, this pigment becomes less and less available. At first, hairs will have a limited amount of pigment and they will appear to be grayish in color. In time, they will lose all of their pigment and will be white. Many things are known to cause graying, and genetics is a very powerful factor. If one of your parents turns gray at an early age, there is a good chance that you will too. Some people begin the graying process in high school, while others may be over the age of forty.

    Constant worry and tension can have many harmful effects on the human body. It is a known fact that stressful times can cause one to suffer hair loss. It would make sense that if it can cause these problems, perhaps it also may contribute to graying. However, there is no sound evidence to support this.

    On the other hand, many medical professionals believe that there may be a link between graying and a constant state of anxiety or tension. Does stress cause gray hair? There is no scientific evidence to support the theory, but it is best to avoid stressful situations.

    Art museums are places where people can learn about various cultures. The increasingly popular "design museums" that are opening today, however, perform quite a different role. Unlike most art museums, the design museums show objects that are easily found by the general public. These museums sometimes even place things like fridges and washing machines in the centre of the hall.

    People have argued that design museums are often made use of as advertisements for new industrial technology. But their role is not simply a matter of sales — it's the honouring of excellently invented products. The difference between the window of a department store and the showcase(玻璃陈列柜) in a design museum is that the first tries to sell you something, while the second tells you the success of a sale.

    One advantage of design museums is that they are places where people feel familiar with the exhibits. Unlike the average art museum visitors, design museum visitors seldom feel frightened or puzzled. This is partly because design museums clearly show how and why mass-produced products work and look as they do, and how design has improved the quality of our lives. Art museum exhibits, on the other hand, would most probably fill visitors with a feeling that there is something beyond their understanding.

    In recent years, several new design museums have opened their doors. Each of these museums has tried to satisfy the public's growing interest in the field with new ideas. London's Design Museum, for example, shows a collection of mass-produced objects from Zippo lighters to electric typewriters to a group of Italian fish-tins. The choices open to design museums seem far less strict than those to art museums, and visitors may also sense the humorous part of our society while walking around the exhibits.

    There are billions of people on this planet, and many of us love to eat meat. In 2018 alone, the average American will consume more than 100 kgs of red meat, according to a report from the US Department of Agriculture (USDA). At the same time, the environmental impact caused by meat consumption – waste, animal treatment, health issues and even the greenhouse gas effects – has given rise to a number of startups (新兴企业) looking for ways to fill our growing demand for meat. But can the demand be filled in a sustainable and affordable way?

    A bunch of companies are not only optimistic but are working to make this happen sooner. All of these companies harvest cells from animals and grow them in a lab. For example, San Francisco-based Memphis Meats is developing cell-based meats in its laboratories by manufacturing fat and muscle cells without requiring any animals. And don't worry if you're not a meat lover. Startups such as Jet Eat, which is based in Israel, are working on food products grown in labs that are plant based and produce meats using natural ingredients while still maintaining flavor, consistency and the "overall sensory experience".

    As you can imagine, there are plenty of hurdles facing the industry. Educating the public is a big one. Another controversial issue is the labelling of the products. Meat industry trade groups have been pressing the USDA to more strictly regulate alternative meats, labeled as "imitation products".

    Many of us have concerns about the challenges facing future generations as our global population swells and the earth's natural resources shrink. The good news is that there are plenty of companies around the world—like those producing lab-grown meats - who are working to solve some of these problems and make a few bucks in the process. Nothing wrong with that.

    Older women who walk a little over three kilometers each day might live longer than less active women of the same age, a new study suggests.

    Many Americans hoping to stay healthy set a daily goal of 10, 000 steps, or about eight kilometers. They often have this goal because they are wearing electronic devices which set that target, note researchers in the United States. Their findings appeared recently in the publication JAMA Internal Medicine.

    But it is not clear how much intensity(强度)or speed matter when counting the health benefits of every step, the researchers write. They add that 10,000 steps per day might not be the right goal for everyone.

    For the study, researchers observed 17,000 women, all in their early 70s. They asked the women to wear accelerometers for at least four days. Accelerometers are small devices that measure the number of steps and the intensity of movement. The researchers followed up with the women much later, around 4. 3 years later, on average. Since the beginning of the study, 504 women had died. Compared to women who took no more than 2, 718 steps daily, the women who took at least 4,363 steps per day were 41 percent less likely to die.

    "Even a modest amount of steps is associated with lower death rates," said I-Min Lee, the lead writer of a report on the study. "The rate of stepping did not matter in these older women: it was the number of steps that mattered.

    The study had a few limitations. For example, the researchers only measured women's movements once, at the start of the study period. It is possible that the women's behaviors changed over time. Still, the results are "good news for older adults who may have difficulty walking at faster paces, "said Keith Diaz, a researcher at Columbia University. He was not involved in the study.

    "Any walking is better than nothing," Diaz said by email. "With even small amounts of walking, your risk of death will be sharply reduced "For those who have difficulty walking, other research shows that any form of aerobic activity provides health benefits," he added. "Swimming, bicycling or any form of activity that is continuous in nature will provide health benefits.