Getting active in midlife could be as good for you as starting young when it comes to reducing the risk of an early death, researchers have suggested. But experts say the study also shows that the benefits fade once exercise declines.

“If you maintain an active lifestyle or participate in some sort of exercise from youth to middle age, you can reduce your risk for dying,” said Dr. Pedro Saint-Maurice, the lead author of the research. “If you are not active and you get to your 40s - 50s and you decide to become active, you can still enjoy a lot of those benefits.”

The study was based on data from more than 300,000 Americans aged 50-71 who undertook a questionnaire(问卷)in the late-1990s. They were asked to recall the extent of their moderate to vigorous (剧烈的) leisure exercise at different stages of their life. Researchers then used national records to track who died in the years up to the end of 2016. After taking into account factors including age, sex, smoking and diet, the team found that those who were exercising into middle age had a lower risk of death than those who had never carried out any leisure exercise. However, when the team looked at different patterns in the way people were active over their life, it found a surprise.

Men and women who started exercising at the age of 40-50 reduced their risk of death from any cause by about 35%. The benefit was similar to that seen for people who reached and maintained similar activity from their teens or 20s onwards.

However, the study found that the protective effect of exercise did not last forever. People whose levels of leisure exercise decreased by middle age had no difference in the risk of an early death to those who had always been couch potatoes. “If you have been active and you slowly decrease your exercise participation as you age, you lose a lot of the benefits that we know are associated with exercise,” Saint - Maurice said.

But the study has limitations, including that it is based on individuals recalling how active they were many years before. What’s more, the research looked only at death records, not other aspects of health such as levels of sickness and disease. Nonetheless, he said, the message was positive. “This adds to the growing body of evidence about the importance of physical activity and exercise across he life course, and indicates that it is never too late to start.”

Researchers have been investigating for years the ways in which screens affect the quality of a person’s reading. The magazine Scientific American reported that at least 100 studies have been published on the issue since the 1980s.

Virginia Clinton carried out a research examination. She is a professor of Education, Health and Behavior at the University of North Dakota. She found what she called a “small but significant” difference in reading text from screen versus paper.

Clinton looked at 33 past studies that examined paper versus screen reading. All of the studies were done between 2008 and 2018. The studies collectively had 2,799 study subjects, including both children and adults. Clinton’s examination found that reading from paper generally led to better understanding and improved a person’s performance on tests connected to the reading material. And, she found no major differences in reading speed between the two.

Clinton and other researchers have found screen readers often believe they understand a text better than they really do. And, they are more likely than paper readers to overestimate how well they would do on a test of the materials they have read.

Yet, this overestimated sense of understanding is especially common among screen readers. Clinton said, “There are many possible reasons for such findings. Overconfidence of reen readers, for example, could be the result of a distracted, less focused mind. Readers’ preferences are also important. Research shows the majority of people of all ages prefer reading from paper. If you are enjoying the reading process, you’re going to be more involved. You’re going to be paying better attention. Preferences are a key issue here.”

Several studies have found that people often think of paper materials as something more important and serious. “If you are reading from paper, your mind thinks this is something important. I need to pay attention to it,” Clinton said.

All the hard work that you’ve spent making strong passwords, combining pet names with numbers, symbols and birthdates could all soon be for nothing as a new artificial intelligence (AI) model achieves a 95% accuracy of understanding keystrokes (按键).

At least that’s the extreme view of a team of British researchers. Using a deep learning model, they were able to steal data from a laptop’s keyboard using a microphone to understand what is being typed. This, in theory, would allow hackers who were able to gain access to your laptop to obtain what is being typed including messages and passwords.

The first step for this attack to work is by recording the keystrokes on someone’s keyboard. This is needed to train the algorithm (计算程序). While this could be done from the laptop’s microphone, it could equally be achieved by placing a smartphone near the computer. By pressing 36 keys on a modern MacBook Pro 25 times each and recording the sounds produced, the researchers gained a full set of training data. This information is turned into waveforms to show identifiable differences between each key. With this information in hand, they could then build a machine-learning model to understand which of these waveforms lines up with which key.

“If you get enough data, a model can be built pretty easily,” Oli Buckley, a professor of Internet security. “If it works on one keyboard, it will likely work on the next. The MacBook has a nice, quiet keyboard, so the idea is that if it works on something quiet, it will have a wide-reaching ability on louder keyboards”.

While this all sounds pretty scary, not to mention a new form of hacking (侵入) to look out for, it isn’t quite as worrying as it sounds.

“A good sample of data is needed for it to work, so this changes if you’re using a Dell, a MacBook or an external keyboard. Also, factors change. Some people type louder and harder, or my keyboards full of cat hair so that impacts things slightly”, says Buckley.