In France, a man walks on what can only be described as a human-sized hamster wheel. The wheel moves around and around, as the man keeps walking. What is he doing? He is lifting a heavy object to the top of a tower the same way workers moved such objects 800 years ago.

    In the 13th century, workers did not have the 100-meter tall cranes they now use to build tall buildings. So they had to be creative and come up with simple machines to get their work done.

    The man on the large wheel is walking at a reasonable speed. The wheel turns and pulls a rope connected to a pulley(滑轮)at the top of the tower. Another rope tied to the pulley lifts supplies from the ground.

    This is just one way skilled craftsmen arc building a 13th-century castle without using modern tools. Crew have been working on the castle since 1997. It is being built in the Burgundy area of central France. Organizers expect the work to last another 10 to 15 years. That means it will take close to 30 years to finish the project.

    The crew are making progress at about half the speed of the workers from 800 years ago. That is because many of them are accustomed to using modern tools. When the crew use heavy chisels(凿子）and hammers to break rock, as they did hundreds of years ago, they are learning as they go. The goal of the project is to learn more about old building techniques in case they might be of use today.

    Clement Guerard, 44,is a stonemason; he cuts and builds with stone. He has been working on the tower for 17 years. He said one way he is able to work on something like this for so long is by forgetting “some of the pace of modern life", he is able to adapt to working by hand.

    Jack was born without eyes. He's very lucky with his timing. He grew up having other kittens to play and socialize with, and was used to people from the moment he was born since there are always kids hanging around the barn. He was a favorite amongst the students at the barn. However, when it came time to find the kittens homes, no one knew where Jack would end up. That's when I got an e-mail from my friend. All she asked was “Do you still want one of the kittens? There's one here with no eyes and no one can take him.” Without thinking I told her that I did want the kitten.

    When we first brought him home Jack stayed mostly in my room. He walked cautiously around, sniffing everything. After about a day he had no issues running around, jumping onto my bed and climbing on everything. He went through a time where he could climb the stairs, but couldn't get down. He would sit at the top and cry until someone came and got him. Every now and then when he gets disoriented he'll stop and cry. But we just call his name and talk to him and it isn't long before he finds his way back to us.

    Also, a few weeks after getting Jack, we got a new barn cat named Bear. I always take Jack outside at that time for some fresh air and exercise. He loves to run (at top speed!) around the back yard and gardens. Bear and Jack have become best friends. It doesn't matter that he can't see, Jack always knows when Bear is around. He'll run across the yard straight to Bear and wrap his front legs around his neck in a big hug. They chase each other around and wrestle, and when they're tired they'll lie down in the grass together.

    Jack is truly an inspiration. I've owned a lot of kittens in my life, but Jack is the happiest, most playful of them all. He doesn't feel sorry for himself. Heck, for all he knows, all cats are just like him. People who know Jack don't feel sorry for him. They cherish him for the treasure that he is. I have talked to a few people who haven't met him personally who tend to pity him, but they just don't understand. Jack doesn't need pity. I think Jean (who has Gumbo the eyeless ginger) said it best when she told me that cats don't have disabilities, they have adaptabilities.

    There might be as many as 10 million species of complex life on this planet today —— a huge number. But add up all of the complex species that ever lived and some biologists think the grand total would be about five billion. The estimate leads to an astonishing conclusion: a staggering 99% of species are not around any more. They have been driven to extinction.

    More species are joining the ranks of the extinct every year. Many scientists believe we are living through an episode of remarkably rapid extinction, on a scale that has been seen only five times in the last half a billion years.

    They call this current episode the sixth mass extinction —— a large, global decline in a wide variety of species over a relatively short period of time. And they tend to agree that humans are the main cause.

    Over-hunting, overfishing, and human-driven habitat loss are pushing many species to the brink. In fact, we have changed the planet so much that some geologists are now suggesting that we have entered a new phase in Earth's history; an epoch they call the ＂Anthropocene＂. By 2100, it is expected that humans will have caused the extinction of up to half of the world's current species.

    Because we are living through this extinction, it is relatively easy for us to study the driving forces behind it. But how do we determine what caused other mass die-offs that happened long ago? To do so we have to look at what archaeologists, palaeontologists, geologists and other scientists have concluded from the evidence they have gathered.

    The trouble is, those scientists do not always agree with one another —— even about the most recent extinction event. As well as the five-or six- mass extinctions, there have also been many smaller extinctions.

    One of these mini extinction events happened towards the end of the Pleistocene, a few tens of thousands of years ago. It is sometimes called the ＂megafaunal＂ extinction because many of the species it claimed were particularly large animals, weighing more than 97lb (44kg). However, its cause remains a debate amongst scientists.

    A European Union program is letting blind people experience famous paintings for the first time. It uses three dimensional (3-D) printing to re-create famous paintings so they can be touched.

    One painting printed with the new technology is Gustav Klimt's “The Kiss.” It is a popular attraction at the Belvedere Museum in Vienna, Austria. The painting shows a man and a woman standing in a field filled with flowers. They are wearing gold robes and have their arms around each other. The man leans down to kiss the woman.

    Klimt finished the painting in 1908. Until now, people who had trouble seeing could not appreciate the artwork. But thanks to the reproduction they can touch the piece and feel the ridges and depressions. Andreas Reichinger started making 3-D versions of artwork in 2010. He said this reproduction was his most difficult project because the couple's robes are so detailed.

    Dominika Raditsch is a blind museum visitor. She touched the reproduction. As she moved her hands around it she said, ”Exactly, can you see these? There are so many details.“ Raditsch said she can imagine what the original painting looks like when she touches the reproduction. “It's somehow round. You can feel it. It comes with it. And in many places it's so smooth. And then I think to myself: it probably shines too!” Raditsch said.

    The Belvedere is not the only museum to have 3-D versions of its artwork. Some of the pieces at the Prado, in Madrid, Spain, have reproductions that can be touched. But the piece in Vienna has one special part: it is made with widely available 3-D printing technology. That means one day, blind art fans anywhere in the world could download the source files and print the reproductions themselves.

    Students perform less well in final exams if smartphones are allowed in class, for non-academic (非学业的) purposes in lectures, a new study in Educational Psychology finds. Students who don't use smartphones themselves but attend lectures where their use is acceptable also do worse, suggesting that smartphone use damages the group learning environment.

    Researchers from Rutgers University in the US performed an in-class experiment to lest whether dividing attention between smartphones and the lecturer during the class affected students' performance in within-lecture tests and a final exam. 118 students at Rutgers University took part in the experiment during one term of their course. Smartphones were not allowed in half of the lectures and allowed in the other half. When smartphones were allowed, students were asked to record whether they had used them for non-academic purposes during the lecture.

    The study found that having a smartphone didn't lower students' scores in comprehension tests within lectures, but it did lower scores in the final exam by at least 5%, or half a grade. This finding shows for the first time that the main effect of divided attention in the classroom is on the length of time in keeping memory, with fewer things of a study task later remembered. In addition, when the use of smartphones was allowed in class, performance was also poorer for students who did not use them as well as for those who did.

    The study's lead author, Professor Arnold Glass, added: "These findings should alarm students and teachers that dividing attention is having a not obvious but harmful effect that is damaging their exam performance and final grade. To help manage the use of smartphones in the classroom, teachers should explain to students the alarming effect—not only for themselves, but for the whole class."

    This is the first-ever study in an actual classroom showing a relationship between losing attention from smartphones and exam performance. However, more researches are required to see how students are affected by using smartphones after school.

    Doctors say you had better use it before you lose it. The more you sit each day, the more chance you have of getting sick.

    Richard Rosenkranz of Kansas State University was among the researchers. He said people who sat for long periods were at great risk of diseases when compared with those who sat less. He said that was especially true for some chronic (慢性的) diseases.

    Richard Rosenkranz studied the relationship between sitting and chronic diseases in middle-aged Australian men. He worked with researchers from the University of Western Sydney. They examined the health records of more than 63,000 men from New South Wales. The men were between the ages of 45 and 65. The men reported about what diseases they had, or did not have. And they kept record of the amount of time each day that they sat.

    The study also showed that exercising every morning for 30minutes did not reduce the health risk if you spend the next eight hours sitting at the desk. Mr. Rosenkranz said it was important to make sure you exercise. But he said it was also important to find ways not to sit so much during the day.

    Many jobs today require sitting and working at the desk all day. James Levine works at the Mayo Clinic in the United Sates. He suggests working while standing at high table some of the time instead of sitting at a desk. Dr. Levine also suggests standing while using the telephone or eating. Or he advises walking with the people you work with for an on-foot meeting. And he notes that if you spend more time on your feet, you may have muscle activity that helps burn fats and sugars in your body.