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.

Quantum (量子) computers have been on my mind a lot lately. A friend has been sending me articles on how quantum computers might help solve some of the biggest challenges we face as humans. I've also had exchanges with two quantum-computing experts. One is computer scientist Chris Johnson who I see as someone who helps keep the field honest. The other is physicist Philip Taylor.

For decades, quantum computing has been little more than a laboratory curiosity. Now, big tech companies have invested in quantum computing, as have many smaller ones. According to Business Weekly, quantum machines could help us "cure cancer, and even take steps to turn climate change in the opposite direction." This is the sort of hype (炒作) that annoys Johnson. He worries that researchers are making promises they can't keep. "What's new," Johnson wrote, "is that millions of dollars are now potentially available to quantum computing researchers.

As quantum computing attracts more attention and funding, researchers may mislead investors, journalists, the public and, worst of all, themselves about their work's potential. If researchers can't keep their promises, excitement might give way to doubt, disappointment and anger, Johnson warns. Lots of other technologies have gone through stages of excitement. But something about quantum computing makes it especially prone to hype, Johnson suggests, perhaps because ""quantum' stands for something cool you shouldn't be able to understand." And that brings me back to Taylor, who suggested that I read his book Q for Quantum.

After I read the book, Taylor patiently answered my questions about it. He also answered my questions about PyQuantum, the firm he co-founded in 2016. Taylor shares Johnson's concerns about hype, but he says those concerns do not apply to PyQuantum.

The company, he says, is closer than any other firm "by a very large margin (幅度)" to building a "useful quantum computer, one that "solves an impactful problem that we would not have been able to solve otherwise." He adds, "People will naturally discount my opinions, but I have spent a lot of time quantitatively comparing what we are doing with others"

Could PyQuantum really be leading all the competition "by a wide margin", as Taylor claims? I don't know. I'm certainly not going to advise my friend or anyone else to invest in quantum computers. But I trust Taylor, just as I trust Johnson.

Over the last seven years, most states have banned texting by drivers, and public service campaigns have tried a wide range of methods to persuade people to put down their phones when they are behind the wheel.

Yet the problem, by just about any measure, appears to be getting worse. Americans are still texting while driving, as well as using social networks and taking photos. Road accidents, which had fallen for years, are now rising sharply.

That is partly because people are driving more, but Mark Rosekind, the chief of the National Highway Traffic Safety Administration, said distracted (分心) driving was "only increasing, unfortunately."

"Big change requires big ideas." he said in a speech last month, referring broadly to the need to improve road safety. So to try to change a distinctly modern behavior, lawmakers and public health experts are reaching back to an old approach: They want to treat distracted driving like drunk driving.

An idea from lawmakers in New York is to give police officers a new device called the Textalyzer. It would work like this: An officer arriving at the scene of a crash could ask for the phones of the drivers and use the Textalyzer to check in the operating system for recent activity. The technology could determine whether a driver had just texted, emailed or done anything else that is not allowed under New York's hands-free driving laws.

"We need something on the books that can change people's behavior," said Félix W. Ortiz, who pushed for the state's 2001 ban on hand-held devices by drivers. If the Textalyzer bill becomes law, he said, "people are going to be more afraid to put their hands on the cell phone."