Bad news sells. If it bleeds, it leads. No news is good news, and good news is no news. Those are the classic rules for the evening broadcasts and the morning papers. But now that information is being spread and monitored(监控) in different ways, researchers are discovering new rules. By tracking people's e-mails and online posts, scientists have found that good news can spread faster and farther than disasters and sob stories.

    “The 'if it bleeds' rule works for mass media,” says Jonah Berger, a scholar at the University of Pennsylvania. “They want your eyeballs and don't care how you're feeling. But when you share a story with your friends, you care a lot more how they react. You don't want them to think of you as a Debbie Downer.”

    Researchers analyzing word-of-mouth communication—e-mails, Web posts and reviews, face-to-face conversations—found that it tended to be more positive than negative, but that didn't necessarily mean people preferred positive news. Was positive news shared more often simply because people experienced more good things than bad things? To test for that possibility, Dr. Berger looked at how people spread a particular set of news stories: thousands of articles on The New York Times' website. He and a Penn colleague analyzed the “most e-mailed” list for six months. One of his first findings was that articles in the science section were much more likely to make the list than non-science articles. He found that science amazed Times' readers and made them want to share this positive feeling with others.

    Readers also tended to share articles that were exciting or funny, or that inspired negative feelings like anger or anxiety, but not articles that left them merely sad. They needed to be aroused(激发) one way or the other, and they preferred good news to bad. The more positive an article, the more likely it was to be shared, as Dr. Berger explains in his new book, “Contagious: Why Things Catch On.”

    China is a big country, and there is no simple answer to the question “When is the best time to visit China? ” There are two best times to visit China, depending on your preference.

    October

    Things to do: hike on the Great Wall, photography tour

    Places to visit: Beijing, Xi'an, Shanghai, Guilin, Jiuzhaigou, Chengdu

The best time to go to China is early autumn (October).

    Most of China has warm temperatures, and the summer rains have stopped (apart from around HongKong and Sanya) so it's pretty dry. The autumnn colours are also amazing. It is quiet at tourist attractions for most of the month, as the summer holiday travel crowds have gone. But try to avoid October 1st -7th, which is the Chinese National Day holiday, as attractions, transport and hotels are packed with Chinese tourists and prices go up a lot.

    Late Spring (April to May)

    Things to do: appreciate flowers, Li River cruise, ethnic festivals

    Places to visit: Beijing, Xi'an, Guilin, Huangshan, GuiZhou, Zhangjiajie

    The second-best time to travel to China is probably in April and May, when the flowers are in bloom and the temperatures are warming up. In late spring, temperatures across China are getting into the 20s (℃), except the extreme northwest and northeast. While the North of China is still dry, the summer rains have already begun in the South. This could actually improve the view in the form of mountain fog in mountainous areas like the Li River and the Yellow Mountains.

    Ethnic festivals in GuiZhou are concentrated in April and May, such as the Sisters' Meal Festival. If you are interested in Miao and Dong ethnic cultures, this is a good time to visit.

    Travel prices are average: cheaper than June to October, but more expensive than the lower season from November to March.

    One day, I received a call from a colleague. He was about to give a student a zero for his answer to a physical problem， while the student claimed a perfect score. I was elected as their arbiter. I read the examination problem: “Show how it is possible to determine the height of a tall building with the aid of a barometer(气压计).” The student had answered: “Take the barometer to the top of the building，attach a long rope to it，lower it to the street， and then bring it up, measuring the length of the rope. The length of it is the height of the building. ”

    The student had really answered the question completely, but the answer didn't confirm his competence in physics. I suggested the student try again. I gave him six minutes to answer the question, warning that the answer should show some knowledge of physics. Five minutes later, he said he had many answers and clashed off one, which read： “Take the barometer to the top of the building and lean over the edge of the roof. Drop the barometer, timing its fall with a stopwatch. Then, use the physical formula (公式）to calculate the height of the building. ”

    At this point, my colleague had to accept it, and then the student made almost full marks. I couldn't help asking the student what the other answers were. He listed many others ，and then added “Probably the best is to take the barometer to the administrator and said to him，' Sir, here is a fine barometer. If you tell me the height of the building, I will give it to you.，”

    Then, I asked the student if he really did not know the conventional answer to this question. He admitted that he did, but said that he was fed up with high school and college instructors trying to teach him how to think.

    The name of the student was Bohr who later was famous all over the world. He won the Nobel Prize for Physics in 1922.

    Eating chips, chocolates and cakes may damage a child's intelligence, according to researchers at Bristol University. Their study suggests a link between diet high in processed(加工的) food and a slightly lower IQ. Writing in the journal of Epidemiology and Community health, they suggest poor nutrition may affect brain development.

    The eating habits of 3,966 children taking part in the Avon Longitudinal Study of Parents and Children were recorded at the ages of three, four, seven and eight and a half. The researchers said three types of diet appeared: processed diet which was high in fat, sugar and fast food, traditional diet of meat, potatoes and vegetables, and healthy diet of salads, fruit and fish. The children all took IQ tests when they were eight and a half.

    The researchers found a link between IQ and diet, even after taking into consideration other factors such as the mother's level of education and social class. Diet high in processed food at the age of three was linked to a slightly lower IQ at the age of eight and a half, suggesting early eating habits have a long-term influence. Dr Pauline Emmett, who carried out the study at Bristol University, said, “Brain development is much faster in early life, and it's when it does most of its growing.”

    Although the relationship between diet and IQ was very strong, the influence was quite small. Processed food was linked with IQs only a few points lower. Experts in the field said the results had shown common sense was right. Fiona Ford, spokesperson for the British Dietetic Association, said, “It's well worth looking at the long-term influence of diet, for everyone's familiar with the short term. The research agrees with the type of advice we already know, but that's not always enough. Sometimes a society has to help a person change; we need to educate more young parents about healthy eating.”

    We often hear stories of animals rescuing people. But now someone has managed to return the favor.

    The event took place one snowy January morning Thomas Smith was walking his dog, Jack, in the park." As I was walking, I just saw Jack running onto the ice towards the ducks in the middle, and then he fell into the water and couldn't climb out, "said Smith. He realized he had no choice but to try and save his dog. "Someone else told me the lake was only one-meter deep, but it was at least twice that. I had to break my way through the 6-cm ice. Finally, I got Jack by the neck, and pulled him out. I don't think I have ever felt so cold by the time we got back to dry land. And when we got there, everyone was asking if Jack was okay no one was particularly worried, about me!"

    A neighbor, Julie Brown, saw it all happen. "The dog went onto an icy lake. All of a sudden, it started to go under. There were crowds of people around, and they were all shouting and screaming. Before I knew it, the owner Smith was in the water forcing his way through the ice. I can't begin to imagine how cold it was. Everyone was very nervous, but he was as cool as a cucumber he just crawled back out, put the dog on its lead, and went home."

    Many regard him as a hero, but Mr. Smith is quite laid-back about it. "Most dog owners are the same as me. They would do what I did without a second thought. But in the future, I'm going to make sure he's on lead near any ice ponds, Pets are members of our family. Would you do the same for them?