Reading can be a social activity. Think of the people who belong to book group. They choose books to read and then meet to discuss them. Now the website BookCrossing.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. BookCrossing provides an identification number to stick inside the book. Then the person leaves it in a public place, hoping that the book will have an adventure, traveling far and wide with each new reader who finds it.

    Bruce Peterson, 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 BookCrossers 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.

    Louis Pasteur was born in Dole, France on December 27, 1822. His family was poor, and during his early education Pasteur was an ordinary student who enjoyed art and singing. However, when Pasteur was exposed to science as a teenager, he knew he had found his career.

    In 1838, Pasteur went to college to become a science teacher. He then became a chemistry professor at the University of Strasbourg. He got married in 1849 and had five children. However, three died young from typhoid fever (伤寒症). It was the deaths of his children that drove Pasteur to investigate the infectious disease in order to find a cure.

    During Pasteur's time, people believed that bacteria (细菌) appeared due to “spontaneous generation (自然发生)”. They thought that the bacteria just appeared out of nowhere. Pasteur earned out experiments to see if this was true. Through his experiments he proved that germs (细菌) were living things that came from other living things. They didn't just spontaneously appear. This was a major discovery in the study of biology and earned Pasteur the title of Father of Germ Theory.

    As Pasteur learned more about bacteria, he began to think they may be the cause of diseases in humans. When the French silk market was threatened by a disease to silkworms (蚕), Pasteur decided to investigate. He discovered that this disease was caused by germs. By killing them from the silkworm farms, he was able to cease the disease and save the French silk business.

    Today Louis Pasteur is known as one of the most important scientists in history. His discoveries led to an understanding of bacteria and diseases that has helped save millions of lives.

    Developed by researchers and designers specializing in typography(印刷术)and behavioral science, Sans Forgetica is a new font(字体)designed to help readers better remember the information they read by forcing them to spend a bit more time on each word.

    The design of Sans Forgetica is based on a font called Albion, but with substantial  modifications(修改)to reduce familiarity and attain its goal of engaging the brain more and helping the reader retain(保留) more information. It was developed by scientists at RMIT University in Melbourne, Australia, who believe it could help students studying for exams.

    “We believe this is the first time that specific principles of design theory have been combined with specific principles of psychology theory in order to create a font, ”Behavioral economist Jo Peryman told DW.

    If fonts are too familiar, readers often glance over them without their brain creating may  memories of what was read. At the same time, if a font is too outlandish, the brain has to struggle too much to decipher(破译)it while neglecting the retention of information. According to its developers, “Sans Forgetica lies at a sweet spot where just enough obstacle has been added to create that memory retention.” Its modifications force readers to spend more time, but not too much time, reading each word, allowing the brain to engage in deeper cognitive processing.

    So does Sans Forgetica actually work? Does it help readers better remember the information they read? So far, studies have shown that it can make a difference, although not a significant one.

    One experiment had 96 participants recall word pairs presented in three different fonts. They remembered 69 percent of the word pairs written in Sans Forgetica, compared to 61 percent for the other fonts. In a different experiment, 303 students took a mock(模拟)multiple-choice exam, and whenever the text was presented in Sans Forgetica, they remembered 57 percent of the text, compared to only 50 percent of the surrounding text written in Arial font.

    So Sans Forgetica won't give you the memory of an elephant, but if you're the kind of person who believes every little bit helps, it might be worth a try.

    Scientists can figure out a movie's emotional tone from the gasps(喘气) of its audience. These gases could point the way to a subtle(微妙的，精细的) form of human communication, a new study suggests.

    "When you see a movie, you can hear the music and see the pictures. However, you don't realize here are chemical signals in the air. And they, too, could be affecting you, says Williams, who led the study. As an atmospheric chemist, he studies the chemical makeup of the air around us.

    Williams started out measuring the air in a soccer stadium. He noticed that levels of carbon dioxide and other gases changed wildly whenever the crowd cheered. That got him wondering -- Could the gases people breathe out be influenced by emotions?

    To find out, he went to the movies.

    Williams and his coworkers measured air samples collected over six weeks in two movie theaters. Overall, 9,500 movie goers watched 16 films. They included a mix of comedy, romance, action and horror films. Among them were The Hunger Games, Catching Fire, Carrie, and Walking with Dinosaurs. The researchers gave scenes from the movies such labels as "suspense(悬疑)", "laughter" and "crying". Then they looked for hundreds of chemicals in the air that showed up as people were watching particular movie scenes.

    And certain scenes had distinct chemical "fingerprints". Scenes that had people laughing or on the edge of their seats were especially distinctive. During screenings of The Hunger Games, levels of carbon dioxide and isoprene got to the highest at two suspenseful moments. Because isoprene is related to muscle movement, the researchers think tense movie moments likely led to its spikes(尖峰). Williams and his colleagues think the increase in carbon dioxide was due to the viewers' increased pulse and breathing rates.

    Scientists need more data to make stronger links between human emotions and what's in their breath. But Williams can see potential practical uses. Companies, for instance, could quickly measure the air during tests to see how people feel about new products. He pictures future studies recording other body variables(变数) as well. These might include heart rate and body temperature, for instance. "It's something to find out."

    Desiree was only four when she lost her Dad. Instead of gradually adjusting to his death, Desiree refused to accept it and even wanted to die so as to be with her father. Concerned about her daughter, Rhonda turned to her mother, Trish Moore, for help.

    November 8 of 1993 would have been Ken's 29th birthday. So Trish advised Desiree to send her father a card. Desiree's eyes lit up as she dictated a letter, "Happy birthday, Daddy. I love you and miss you. I hope you get this and can write to me on my birthday." Trish wrote the message and their address on a small piece of paper and tied it to the end of the string on a balloon with a drawing of the Little Mermaid (美人鱼). Finally, Desiree released the balloon.

    On November 12 in eastern Canada, Wade MacKinnon was duck-hunting. Suddenly something in the bushes caught his eye. Curious, he approached to find a silver balloon. The letter finished with a mailing address in Live Oak, California. The balloon traveled 3,000 miles. What a coincidence! A Little Mermaid balloon landed at Mermaid Lake. To help Desiree, the MacKinnons wrote her a letter with a birthday card and an adaptation of The Little mermaid.

    The MacKinnons' package arrived later on Desiree's birthday. The letter read, "Happy birthday from your daddy. You must be wondering who we are. Well, it all started... There are no stores in heaven, so your daddy picked us to do the shopping. We know your daddy loves you very much and wants you to be happy and not sad. Lots of love, the MacKinnons."

    Tears in eyes, Desiree said, "I knew Daddy would find a way not to forget me." Next, Trish began to read the Little Mermaid to her, in which the mermaid was finally carried away by angels. "The mermaid goes to heaven just like Daddy!" Desiree said with delight. She understood then her father was with her always.

    The Secretary-General of the U.N. has always been chosen in private meetings. But for the first time in its 70-year history, part of the selection process is taking place in public.

    At least eight countries have announced their candidates (候选人) for the position, among whom are women, including Irina Bukova from Bulgaria, Susana Malcorra from Argentina and Helen Clark from New Zealand. 56 countries says the next U.N. chief should be a woman. There have been eight U.N. chiefs, none of whom was a woman.

    All member states were permitted to ask the candidates questions during two hour-long meetings last week in the U.N. General Assembly (联合国大会). The candidates were also asked some of the 1,000 questions written by people on social media.

    They were asked questions about development, how they would improve efforts to create peace and how they would protect human rights.

    The U.N. Security Council will examine the candidates' backgrounds. Then the 15 members will vote secretly until one person is chosen. The General Assembly will then vote on whether to accept the choice.

    Britain, China, France, Russia and the United States are the five permanent members of the Security Council. Experts say they are likely to have more influence on who will be the new secretary-general than the 10 non-permanent nations on the council.

    The Security Council will begin to discuss who will be named the next secretary-general in July. A new secretary-general may not be confirmed until as late as November.

    The U.N. has a tradition of choosing its new leader from a part of the world different from its current leader. U.N. Secretary-General Ban Ki-moon is from Asia. The previous U.N. chief was Kofi Annan, who was from Africa.

    Dan Thomas is a spokesman for the president of the General Assembly. He says there is no rule that says where a new secretary-general must come from. But most observers say the new U.N. chief will not be from Asia or Africa.