Exercise may help to safeguard the mind against depression through previously unknown effects on working muscles, according to a new study involving mice.

    Mental health experts have long been aware that even mild, repeated stress can contribute to the development of depression and other mood disorders in animals and people. Scientists have also known that exercise seems to cushion against depression. But precisely how exercise, a physical activity can lessen someone's risk for depression, a mood state, has been mysterious. So for the new study, researchers at the Karolinska Institute in Stockholm studied the brains and behavior of mice in a complicated and novel fashion.

    We can't ask mice if they are feeling cheerful or in low spirits. Instead, researchers have pictured certain behaviors that indicate depression in mice. If animals lose weight, stop seeking out a sugar solution when it's available — because, probably, they no longer experience normal pleasures — or give up trying to escape from the cold-water zone just freeze in place, they are categorized as depressed. And in the new experiment, after five weeks of frequent but low-level stress, such as being lightly shocked, mice displayed exactly those behaviors. They became depressed.

    The scientists could then have tested whether exercise blunts (延缓) the risk of developing depression after stress by having mice run first. But, frankly, from earlier research, they wanted to know how, so they bred pre-exercised mice. A wealth of earlier research by these scientists and others had shown that aerobic exercise, in both mice and people, increases the production within muscles of an enzyme (酶) called PGC-1alpha. The Karolinska scientists suspected that this enzyme somehow creates conditions within the body that protect the brain against depression. Then, the scientists exposed the animals, which without exercising, were in high levels of PGC-1alpha to five weeks of mild stress. The mice responded with slight symptoms of worry. But they did not develop depression. They continued to seek out sugar and fought to get out of the cold-water zone. Their high levels of PGC-1alpha appeared to make them depression-resistant. Finally, to ensure that these findings are relevant to people, the researchers had a group of adult volunteers complete three weeks of frequent endurance training, consisting of 40 to 50 minutes of moderate cycling or jogging. The scientists conducted muscle biopsies (活体检查) before and after the program and found that by the end of the three weeks, the volunteers' muscle cells contained substantially more PGC-1alpha than at the study's start. The finding of these results, in the simplest terms, is that “you reduce the risk of getting depression when you exercise,” said Maria Lindskog, a researcher at the Karolinska Institute.

    Tourism probably started in Roman times. Rich Romans visited friends and family who were working in another part of the Roman empire. But when the empire broke down, this kind of tourism stopped.

    In the early 17th century, the idea of the “Grand Tour” was born. Rich young English people sailed across the English Channel（英吉利海峡）. They visited the most beautiful and important European cities of the time, including Paris in France, and Rome and Venice（威尼斯）in Italy. Their tours lasted for two to four years, and the tourists stayed a few weeks or months in each city. The “Grand Tour” was an important part of young people's education—but only for the rich.

    In the 18th century, tourism began to change. For example, people in the UK started to visit some towns, such as Bath to “take the waters”. They believed that the water there was good for their health. So large and expensive hotels were built in these towns.

    In the 19th century, travel became much more popular and faster. When the first railways were built in the 1820s, it was easier for people to travel between towns, so they started to go for holidays by the sea. And some started to have holidays in the countryside as cities became larger, noisier and dirtier.

    Traveling by sea also became faster and safer when the first steamships were built. People began to travel more to far-away countries.

    The 20th century saw cars become more and more popular among ordinary people. Planes were made larger, so ticket prices dropped and more people used them.

    Thus tourism grew. In 1949, Russian journalist Vladimir Raitz started a company called Horizon Holidays. The company organizes everything—plane tickets, hotel rooms, even food—and tourists pay for it all before they leave home. The package tour and modern tourist industry was born.

    The first travel agency in China was set up as early as 1949. But tourism did not take off until 1978. In 2002, the industry was worth 500 billion Yuan and became an important part of China's social development.

    I was in a terrible mood. Two of my friends had gone to the movies the night before and hadn't invited me. I was in my room thinking of ways to make them sorry when my father came in.

    "Want to go for a ride, today, Beck? It's a beautiful day."

    "No! Leave me alone!" Those were the last words I said to him that morning. My friends called and invited me to go to the mall with them a few hours later. I forgot to be mad at them and when I came home to find a note on the table. My mother put it where I would be sure to see it.

    "Dad has had an accident. Please meet us at Highland Park Hospital".

    When I reached the hospital, my mother came out and told me my father's injuries were extensive. "Your father told the driver to leave him alone and just call 911, thank God! If he had moved Daddy, there's no telling what might have happened. A broken rib（肋骨）might have pierced（穿透）a lung..."

    My mother may have said more, but I didn't hear. I didn't hear anything except those terrible words: Leave me alone. My dad said them to save himself from being hurt more. How much had I hurt him when I hurled those words at him earlier in the day?

    It was several days later that he was finally able to have a conversation. I held his hand gently, afraid of hurting him.

    "Daddy… I am so sorry…"

    "It's okay, sweetheart. I'll be okay. "

    "No," I said, "I mean about what I said to you that day. You know, that morning?"

My father could no more tell a lie than he could fly. He looked at me and said. "Sweetheart, I don't remember anything about that day, not before, during or after the accident. But I remember kissing you goodnight the night before. "He managed a weak smile.

    My English teacher once told me that words have immeasurable power. They can hurt or they can heal. And we all have the power to choose our words. I intend to do that very carefully from now on.

    Reading can be a social activity. Think of the people who belong to book groups. They choose books to read and then meet to discuss them. Now, the website Book Crossing.com turns the page on the traditional idea of a book group.

    Members go on the site and register the books they own and would like to share. Book Crossing provides an identification number to stick inside the book. Then the person leaves it in a public lace hoping that the book will have an adventure, traveling far and wide with each new reader who finds it.

    Bruce Pederson, the managing director of BookCrossing, says, "The two things that change your life are the people you meet and books you read. BookCrossing combines both."

    Members leave books on park benches and buses, in train stations and coffee shops. Whoever finds their book will go to the site and record where they found it.

    People who find a book can also leave a journal entry describing what they thought of it. E-mails are then sent to the BookCrossing to keep them updated about where their books have been found. Bruce peterson says the idea is for people not to be selfish by keeping a book to gather dust on a shelf at home.

    BookCrossing is part of a trend among people who want to get back to the "real" and not the virtual(虚拟). The site now has more than one million members in more than one hundred thirty-five countries.

Notice for Tourists to Beijing Expo 2019

    The 2019 Beijing Horticultural Expo (园博会) from April 29 to October 7 is an opportunity for international discovery, where cultural elements of different places in China are on display, as well as gardens and buildings about each country's wonderful culture and history. Here is a notice for whoever plans to come.

    Quick Entry by Showing ID Cards.

    To make sure your quick and orderly entry into the Expo Site, please wait in lines and get your ID card ready for pre-check, ticket check and security inspection before entering. During the ticket check, those who hold discounted tickets must provide the materials about discount.

    Safe Tour to the Expo.

    Considering your personal safety, please don't take anything that may disturb other visitors or the order of the Expo Site, such as pets, kites, and speakers. Except for wheelchairs for the elderly and the disabled and strollers (婴儿推车)for children, no vehicles(机动车辆)are allowed to enter the Expo Site.

    Taking Action to Protect the Environment.

    To create a green, beautiful environment for yourself and others, please follow the travel rules, protect public buildings, keep environment clean and care plants growing in the Expo Site. Behaviors such as climbing or destroying structures and exhibits are not permitted.

    Orderly Travel by Limiting the Number.

    For the safety of visitors, sometimes staff members may limit the number of tourists into some gardens and buildings in the event of overcrowding Thank you for your understanding.

    Enjoying Service and Having Fun.

    Tourist service centers in the Expo Site provide services including information inquiry (查询) storage of personal belongings, wheelchair and stroller renting, lost found service, and search for missing persons. We hope you have a good time at the Expo.

    You can call the service hotline at 86-10-86484017 for inquiry, suggestion or complaint. Thanks for your attention.

    There is always no lack of ordinary people taking action for extraordinary change. Aghan Oscar is just among them. Thirteen years ago, Aghan bothered by the ever-increasing quantity of plastic waste in this low-income suburb of Nairobi, decided to find a way to recycle it.

    Nou his company. Continental Renewable Energy Co.Ltd(COREC) produces poles for use in construction, farming and road signs. So far he's sold 96,000, and he says his potential or growth is limited only by the considerable expense of setting up plastic recycling plants.

    Most of Aghan's customers are farmers and developers who once used wooden fence poles. Customers say they have other benefits as well. "I have fenced my piece of land three times using wood posts, but most of the time the fence was vandalized(故意破坏)by villagers who used the posts as firewood." said Caleb Kapten. Now plastic posts have stopped the problem, he said.

    The Kenya National Highways Authority is one of COREC s biggest customers. It approached the company after road signs were vandalized by criminals who sold the metal poles to steel manufacturing companies. Aghan reckons (估计)that COREC's products have saved the government millions of shillings, besides preventing road accidents. And he also points out that COREC has been able to conserve large numbers of trees by producing plastic poles.

    When Aghan started this recycling business in 2003, most of his employees were his family members due to financial constraint(限制).Now he employs 250 young people to collect plastic waste. Fifty more youths work on the production line, where the waste is sorted according to quality before being crushed and washed, melted and cast into different shapes. The poles arc then arranged by shape and size for sale in the yard of the recycling plant.