Have you ever been hungry and sleepy and wished you could solve both problems at once? If you were a reindeer (驯鹿) , it would be easy. According to a new research, these talented deer can have a snooze while they eat their food.

Reindeer live in the Arctic and other northern regions where the winters are extremely dark and cold. Food can be rare in winter, so during the warmer months the deer must eat as much as they possibly can.

Like cows, reindeer use a process called rumination (反刍) to break down the tough plant they eat. This process involves passing the food back and forth between their mouth and the four “stomachs”, chewing it repeatedly until all the nutrients (营养) have been absorbed. In summer, all that chewing seems to leave very little time for sleep.

To find out their secret to getting enough rest, scientists fitted four reindeer with devices that monitored their brain waves. While the reindeer were ruminating, their brain waves were similar to the patterns shown during sleep. The animals sat or stood quietly with their eyes closed, and they were less likely than usual to react to. the movements of a neighbouring deer. “They were in a very relaxed state, ” researcher Melanie Furrer said.

The chewing movement made it hard for the researchers to tell whether, the animals’ brain waves were truly in sleep mode. But when they tested the deer again after rumination, the animals' brain activity showed that they felt rested.

If reindeer are kept awake for too long, they need extra “recovery sleep” to catch up. After ruminating, however, the deer did not need as much recovery sleep. Study co-author Gabriela Wagner said that ruminating serves two different purposes at the same time —eating and sleeping.

Here’s a new reason to be an optimist. 【小题1】 Pessimists, of course, might have suspected this all along-but now there’s actual research behind it.

Boston-area scientists found the most optimistic people live an average of 11 to 15 percent longer than their more pessimistic peers.

In previous studies, researchers have found that more optimistic people tend to have lower risk of diseases and early death, said Lewina Lee, the lead researcher and a psychiatry professor at Boston University School of Medicine. “【小题2】“

Optimists generally expect good things to happen in the future and feel like they can control important outcomes. They tend to stay positive whatever comes their way.

【小题3】 There’s good news: The mind-set is about 25 percent hereditary (遗传的). Lee said, meaning people have some control over their level of good thoughts. She said people can become more optimistic by imagining a future in which their goals have been reached.

To conduct their research. Lee and the other scientists compared results from two independently conducted studies-one that followed nearly 70,000 women for a decade and another that followed about 1,400 men for 30 years. 【小题4】 They ranked themselves on statements including in uncertain times, “I usually expect the best” or “I'm always optimistic about my future.”

The conclusion that optimistic people tend to live longer holds true regardless of other factors, Lee said.

The study leaves one question unanswered: 【小题5】 Although it's unclear, the researchers believe optimists may be better at regulating stressors and bouncing (反弹) back I from upsetting events. Optimists also generally have healthier habits, like exercising more and smoking less.

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.