New research has found that even if you give up smoking, the damage it has done to your genes (基因) will stay there for a much longer time.

In the research, a team of US scientists studied the blood of 16, 000 people. Among them, some were smokers, some used to smoke, and the rest were non­smokers. Scientists compared their genes and found that more than 7, 000 genes of smokers had changed—a number that is one­third of known human genes.

According to NBC News, both heart disease and cancer are caused by genetic changes. Some people may have had the changes when they were born, but most people get them in their day­to­day lives while doing things like smoking.

When you stop smoking, a lot of these genes will return to normal within five years. This means your body is trying to heal (治愈) itself of the harmful effects of smoking. But the changes in some of the genes stay for longer. They can stay for as long as 30 years. It’s almost like leaving a footprint on wet cement (水泥) — it will always be there, even when you’ve walked away and when the cement becomes dry.

Although the study results may make people unhappy, there is a bright side:the findings could help scientists invent medicine to treat genetic damage caused by smoking or find ways to tell which people have heart disease or cancer risks.

An afternoon nap could improve your cognitive abilities, study says. Taking an afternoon snooze (打盹) could keep your brain sharp, a new study has said. Adults aged 60 and older who took afternoon naps showed signs of better mental sharpness compared to those who didn’t nap, according to a study published in General Psychiatry earlier this week.

Researchers analyzed napping habits in 2,214 older Chinese people and measured their cognitive abilities using several cognitive tests. Participants took the Mini-Mental State Examination and the Beijing version of the Montreal Cognitive Assessment, both of which test for memory, language and other cognitive abilities. In every category listed in the study, nappers tested statistically higher on average compared to their non-napping counterparts.

Researchers did not gather data from people under 60, so a connection cannot be drawn between napping and younger generations. The study also noted that there are conflicting studies about the benefits and risks of napping.

Sleeping behaviors can be affected by a large number of factors. Daily routines, medication use and sleep disorders can all play a role in how frequently someone takes a nap.

Neubauer recommended taking a shorter “power nap” of up to 20 minutes to decrease the chances of changing into slow-wave sleep, which makes people feel very tired when they wake up. Napping can be a healthy part of an older adult’s day, but make sure sleepiness isn’t due to a treatable nighttime sleep disorder. Older individuals who want to do all they can to preserve their cognitive functioning should deal with nighttime sleep first.

The first thing we notice about new people are their faces. The next time we see these people, we remember them because we remember their faces. This seems like a simple process. However, scientists found that it is not such a simple process. The section of the brain that is responsible for face recognition seems to work differently for different people. Some people have great difficulty remembering and recognizing faces, while others almost never forget a face.

Normal babies are born with a natural ability to recognize faces. In fact, their face recognition abilities are much better than their parents. Babies are most highly skilled at face recognition at six months. But by nine months, they lose this skill. By nine months, a baby’s face-recognition skills are about the same as an adult’s.

Unfortunately, some people are not born with this ability to recognize faces. The part of the brain that is responsible for face recognition doesn’t work for them. This condition is called face blindness. People with very severe face blindness cannot even recognize their own faces. In fact, people with this condition can sometimes be frightened when they look in the mirror. They don’t recognize their own face, so for a second they are startled when they see this unfamiliar face.

Face blindness is not always severe. Scientists believe up to 10 percent of the population may be affected by face blindness to some degree, yet many people with mild face blindness might not even know they have it. They have no reason to know they are different from anyone else until someone points it out. This is similar to people with color blindness. Colorblind people can’t see the difference between certain colors such as red and green, until someone tells them that green and red are two different colors.

There is no cure for face blindness. So for the time being, people with face blindness need to find simple techniques to compensate for their problem. They can try to recognize people by their hairstyle, their voice, or their glasses. Hopefully, in the future as scientists learn more about this condition, they may find a cure.