【推荐2】Memory loss is a common part of aging. A decade-long study of older adults in China has found that a healthy lifestyle is linked to slower memory loss even when people carry a risky gene for Alzheimer’s(阿尔茨海默氏症). Researchers from China’s National Center for Neurological Disorders and other medical organizations followed 29,000 people aged at least 60 years for up to 10 years. Forty-nine percent of the participants were women.

At the beginning of the study in 2009, the researchers tested the participants memory function with the Auditory Verbal Learning Test(AVLT 听觉词语学习测验). They were also tested for the APOE gene, the most common gene linked with Alzheimer’s. Around 20 percent of the participants were carriers of the risk gene. The participants received tests in 2012, 2014, 2016 and 2019. In the follow-ups, six healthy lifestyle factors were analyzed: a healthy diet, regular physical exercise, active social contact, active cognitive activity, non-smoking and never drinking alcohol.

The results showed that the AVLT scores continuously decreased over the 10 years. But the highest test scores were in the favorable group and the lowest in the group where people usually have an unhealthy lifestyle. The participants with favorable and average lifestyles, even when they were APOE carriers, had a slower rate of memory loss than the participants with unhealthy lifestyles.

The researchers said that they studied the contribution of each lifestyle factor and their combined effects in a large sample size over an entire 10 years and offered important information to protect older adults against memory loss.

The results about the APOE carriers also provide a positive outlook that healthy lifestyle risks are related to a slower rate of memory loss, regardless of the genetic risk.

【推荐3】Math geeks (奇葩) know what March 14 means. It’s Pi Day. Not Pie Day — although Pi Day is a good excuse to have some actual pie. This holiday honors one of math’s most famous constants: pi.

But what does pi actually mean? Read on to find out.

The number pi, or is a ratio that’s equal to the circumference of a circle divided by the circle’s diameter. That comes out to about 3.14159. This is true for circles of all sizes, from pennies to pizzas to planets. Pi’s value is often rounded to 3.14, which is why Pi Day is celebrated on March 14, or 3/14. It’s also why one Earth-sized planet orbiting another star every 3.14 days has the nickname “Pi Earth”.

But the exact value of pi is actually impossible to write out. Last year. A powerful computer calculated pi to a record-breaking 62.8 trillion digits. No one, though, will ever get to the end of pi. That’s because the digits go on forever.

Historians aren’t sure when people first discovered pi, but its been around for almost 4,000 years. Ancient Greeks and Babylonians knew it, and maybe the Egyptians used pi to build the pyramids.

Today just about all math involving circles users pi. It helps engineers map out the path of satellites Pi also helps describe other kinds of curves, such as light waves and sound waves.

Some people want to knock pi off its pedestal (神坛). They think another constant might make math easier to learn. That constant is tau, or DŽ. It is equal to 2. In math angles are often measured in radians (弧度). And while pi is the number of radians in half a circle, tau is the number of radians in a whole circle. So, equations written with tau might help people understand and enjoy math more, tau supporters say.

Of course, a simple pi-to-tau switch may not win over everyone. But if you’ve got anxiety about maths, never fear. Science has revealed some ways to manage that stress. That way, you can have your pi and enjoy math, too.