【推荐1】A new study has found that smiling at London bus drivers increases happiness. However, on the Number 24 bus to Hampstead Heath, Londoners are sceptical. “Bus drivers,” says Liz Hands, a passenger, “are generally annoying.”

It might seem improbable that a report on London’s buses could change behaviour. But it has happened before. London’s buses have an underappreciated role in the history of medical science. In the 1940s, a single study of London’s transport workers transformed epidemiology (流行病学), medicine and the way we live now. Every time you go on a run, check your step-count, or take the stairs instead of the lift, you are following a path pioneered by the feet of the workers on London’s buses.

In the late 1940s, doctors were worried. Britain, like many rich countries, was suffering from an “epidemic” of heart disease and no one knew why. Various hypotheses, such as stress, were suggested; but one thing that was not exercising researchers was exercise. The idea that health and exercise were linked “wasn’t the accepted fact that we know today”, says Nick Wareham, a professor of epidemiology at Cambridge University. Some even felt that “too much physical activity was a bad thing for your health”. Miners and farmers who did physical exercise also suffered from various diseases and died young.

At this time a young doctor called Jerry Morris started to suspect that the increasing deaths from heart disease might be linked to occupation. He began studying the medical records of 31,000 London transport workers. His findings were breathtaking: conductors, who spent their time running up and down stairs, had an approximately 30% lower possibility of disease than drivers, who sat down all day. Exercise was keeping people alive.

Morris’s research was eventually published in 1953, just three years after a study by Richard Doll proving the link between smoking and lung cancer. Morris’s work had consequences both big and small. Morris now also took up exercise, handing his jacket to his daughter and just running. “People thought I was bananas.” Slowly, the rest of the world took off its jacket and followed.

【推荐1】Do you know what “zero” means? Have you ever even stopped to think much about this concept (概念)? It’s an easy one to take for granted. Of course, everyone can understand the concept of nothing, or having nothing.

But did you know that some animals can understand zero as well? Experiments with monkeys and birds have proven that they can master this concept. But now, the understanding of zero has been found in a most unlikely candidate (候选人): bees.

According to a recently published study in the journal Science, Australian and French researchers worked together to conduct experiments to prove that bees are the first insects to “understand that zero belongs at the lower end of a sequence (序列) of numbers”, according to a report by Science Daily.

Scarlett Howard, a researcher at RMIT University in Melbourne, trained bees to choose from several cards with different numbers of shapes printed on them. Correctly choosing the card with the fewest shapes earned them a reward of sugar water. For example, the bees learned to choose three elements when presented with three VS four; or two elements when presented with two VS three. And then these bees were presented a challenge — a card that was entirely blank and that they had never seen before. But 64 percent of the time, they chose to fly toward the blank card instead of the card that had shapes on it. This suggests that the insects understand that zero stands for something less than two or three, according to Science magazine.

Associate Professor Adrian Dyer, also from RMIT University, said the number zero was the basis of modern mathematical and technological progress.

He told Science Daily that the findings have opened a door to new understandings of how different brains understand zero. “If bees can understand zero with a brain of less than a million neurons (神经元) [compared with the 86,000 million neurons of a human brain], it suggests there are simple and efficient (有效的) ways to teach artificial (人工的) intelligence new tricks .”

【推荐3】What’s your opinion about finding good friends? Speaking from my past experience, it is very difficult to find good friends that you can trust but once you have found them, they are worth keeping forever! Therefore, I think friendship is the most important relationship that anybody could have.

The qualities I look for in a friend are a good sense of humor and sensitivity. A friend would have to be strong-minded and highly spirited. I think that these qualities are the key qualities to look for in a good friend.

Even the best friends can still have arguments between themselves, though usually about more serious topics, rather than the usual childish arguments. Some matters can seriously affect friendship. If one of your friends started experimenting with harmful and dangerous drugs, what would you do? A good friend would try to help as much as possible, while a bad example of a friend would simply shrug and turn a blind eye.

Not only the bad things affect friendship—good activities do too, such as bonding with one another, not just by going out on a night with them, but by spending quality time with them and talking to each other. This is a key aspect of a good friendship.

Good friends do not always have to be in the same age group as you. I have a good friend and she is 47 years old and I am 16.

Unfortunately, some people lose contact with their friends as they grow older, which is a sad way to lose a good friend.

I think friendship is one of the most important things in life because if you have no friends you will have no happiness.