The benefits of regular exercise are well documented but there's a new bonus to add to the ever-growing list. New researchers found that middle-aged women who were physically fit could be nearly 90 percent less likely to develop dementia (失智症) in later life and is they did, it came on a decade later than less sporty women.

Lead researcher Dr. Helena Horder, of the University of Gothenburg in Sweden, said: "These findings are exciting because it's possible that improving people's cardiovascular (心血管的) fitness in middle age could delay or even prevent them from developing dementia."

For the study, 191 women with an average age of 50 took a bicycle exercise test until they were exhausted to measure their peak (最大值的) cardiovascular capacity. The average peak workload was measured at 103 watts. A total of 40 women met the criteria for a high fitness level, or 120 watts or higher.

A total of 92 women were in the medium fitness category: and 59 women were in the low fitness category, defined as a peak workload of 80 watts or less, or having their exercise tests stopped because of high blood pressure, chest pain or other cardiovascular problems.

These women were then tested for dementia six times over the following four decades. During that time, 44 of the women developed dementia. Five percent of the highly fit women developed dementia, compared to 25 percent of the women with medium fitness and 32 percent of the women with low fitness

"However, this study does not show cause and effect between cardiovascular fitness and dementia it only shows an association. More research is needed to see if improved fitness could have a positive effect on the risk of dementia and also to look at when during a lifetime a high fitness level is most important" She also admitted that a relatively small number of women were studied, all of whom were form Sweden so the results might not be applicable to other groups.

A machine can now not only beat you at chess, it can also outperform you in debate. Last week, in a public debate in San Francisco, a software program called Project Debater beat its human opponents, including Noa Ovadia, Israel's former national debating champion.

Brilliant though it is, Project Debater has some weaknesses. It takes sentences from its library of documents and prebuilt arguments and strings them together. This can lead to the kinds of errors no human would make. Such wrinkles will no doubt be ironed out, yet they also point to a fundamental problem. As Kristian Hammond, professor of electrical engineering and computer science at Northwestern University, put it: "There's never a stage at which the system knows what it's talking about."

What Hammond is referring to is the question of meaning, and meaning is central to what distinguishes the least intelligent of humans from the most intelligent of machines. A computer works with symbols. Its program specifies a set of rules to transform one string of symbols into another. But it does not specify what those symbols mean. Indeed, to a computer, meaning is irrelevant. Humans, in thinking, talking, reading and writing, also work with symbols. But for humans, meaning is everything. When we communicate, we communicate meaning. What matters is not just the outside of a string of symbols, but the inside too, not just how they are arranged but what they mean.

Meaning emerges through a process of social interaction, not of computation, interaction that shapes the content of the symbols in our heads. The rules that assign meaning lie not just inside our heads, but also outside, in society, in social memory, social conventions and social relations. It is this that distinguishes humans from machines. And that's why, however astonishing Project Debater may seem, the tradition that began with Socrates and Confucius will not end with artificial intelligence.

Leslie Nielsen's childhood was a difficult one, but he had one particular shining star in his life — his uncle, who was a well-known actor. The admiration and respect his uncle earned inspired Nielsen to make a career（职业）in acting. Even though he often felt he would be discovered to be a no-talent, he moved forward, gaining a scholarship to the Neighborhood Playhouse and making his first television appearance a few years later in 1948. However, becoming a full-time, successful actor would still be an uphill battle for another eight years until he landed a number of film roles that finally got him noticed.

But even then, what he had wasn't quite what he wanted. Nielsen always felt he should be doing comedy but his good looks and distinguished voice kept him busy in dramatic roles. It wasn't until 1980—32 years into his career — that he landed the role it would seem he was made for in Airplane! That movie led him into the second half of his career where his comedic presence alone could make a movie a financial success even when movie reviewers would not rate it highly.

Did Nielsen then feel content in his career? Yes and no. He was thrilled to be doing the comedy that he always felt he should do, but even during his last few years, he always had a sense of curiosity, wondering what new role or challenge might be just around the corner. He never stopped working, never retired.

Leslie Nielsen's devotion to acting is wonderfully inspiring. He built a hugely successful career with little more than plain old hard work and determination. He showed us that even a single desire, never given up on, can make for a remarkable life.