【推荐3】If you’re one of those people who have trouble falling asleep, listen up. You might fall asleep 15 minutes earlier and wake up far less during the night if you put on a pair of socks at bedtime.

To understand why, you first need to understand the relationship between core body temperature and sleep. During daylight hours, the human body keeps at an average temperature of 37 degrees Celsius. But at night, your core body temperature reduces as much as 1.2 degrees Celsius over the course of six or seven hours of sleep.

It turns out that this gradual decrease in core body temperature is a key part of the complex neurobiological dance (神经生物学行为) of falling asleep and staying asleep. And the faster you can lower the core body temperature, the faster you will fall asleep.

One of the ways your body regulates (调节) its temperature is through blood vessels (血管) in your skin. If the brain decides the body is too hot, it will widen blood vessels, guiding warmer blood from the body’s core to the rest of the body to cool it down. If the body is too cold, the brain signals the opposite reaction, limiting the flow of blood to the surface.

According to researchers, warming the feet before going to sleep promotes vasodilation (血管舒张) by using a warm foot bath or wearing socks, which in turn lowers the body’s core temperature faster than going to sleep with cold, bare feet.

Scientists think socked feet may have a neurological effect as well. Inside the PO/AH of the brain is a type of a warm-sensitive neuron (热敏神经元), helping us fall asleep and stay asleep. And if that’s the case, warming up the feet before bedtime gives warm-sensitive neurons an extra power.

In a study, Korean researchers found that wearing a pair of special “sleeping socks” not only quickened sleep, but lengthened overall sleep time by an average of 30 minutes and cut nighttime waking period in half.

【推荐1】Even though they are lifeless objects, sand dunes (沙丘) can “communicate” with each other, researchers have found. A team from the University of Cambridge has found that as they move, sand dunes interact with their downstream neighbours and force them away.

It’s well-known that active sand dunes move around. Generally speaking, smaller dunes move faster and larger dunes move slower. And what hasn’t been understood is whether and how dunes within a field interact with each other.

“There are different views on dune interaction: one is that dunes of different sizes will hit each other until they form one giant dune.” said Karol Bacik, the study’s author. Now, Bacik and his workmates have shown results that query these explanations.

Water-filled flumes (水槽) are common tools for studying the movement of sand dunes in a lab setting, but the dunes can only be observed until they reach the end of the flume. Instead, Dr Nathalie Vriend, who led the research, and the members of her lab designed a circular flume, so that the dunes could be observed for hours, while high-speed cameras allowed them to record the movement of the dunes.

The two dunes in the study started with the same amount of sand. As the flow began to move across the two dunes, they started moving. At first, the front dune moved faster than the back dune, but as the experiment continued, the front dune began to slow down, until the two dunes were moving at almost the same speed. Besides, the type of flow across the two dunes was observed to be different: the front dune changed the flow’s direction, generated swirls (旋涡) on the back dune and pushed it away. As the experiment continued, the dunes got further and further apart.

“The next step for the research is to find evidence of large-scale and complex dune migration in deserts. By tracking clusters of dunes over long periods, we can observe whether measures to change the migration of dunes are effective or not, which will be a way to cope with the desertification (沙漠化),” Vriend said.

【推荐2】The oceans play a crucial role in lightening global warming by absorbing carbon dioxide emissions. However, in a study conducted by the University of Texas, researchers found that the oceans’ capacity to absorb carbon dioxide (CO₂) would reach its maximum by 2100 and decrease to half of its current efficiency by 2300, based on a climate simulation (模拟) that was set for a worst-case emissions scenario (设想).

The decline happens because of a surface layer of low-alkalinity (碱度) water that can hinder the ability of the oceans to absorb CO₂. Alkalinity affects how much CO₂ can dissolve in seawater. Although the emissions scenario used in the study is unlikely because of global efforts to limit greenhouse gas emissions, the findings reveal a previously unknown tipping point that if activated would release an important brake on global warming.

“We need to think about these worst-case scenarios to understand how our CO₂ emissions might affect the oceans not just this century, but next century and the following centuries. Climate simulations had previously shown that the oceans slow their absorption of CO₂ over time, but none had considered alkalinity as an explanation. We recalculated pieces of a 450-year simulation until we hit on alkalinity as a key cause of the slowing.” said Megumi Chikamoto, who led the research at the University of Texas Institute.

The effect begins with extreme climate change, which slows ocean currents. This leaves the surface of the oceans covered in a warm layer of fresh water that won’t mix easily with the cooler, more al kaline waters below it. That means more of it is left behind in the atmosphere. This in turn produces faster warming, which sustains and strengthens the low-alkalinity surface layer. Co-author, Pedro DiNezio, said that the discovery was a powerful reminder that the world needs to reduce its CO₂ emissions to avoid crossing this and other tipping points.

【推荐3】U.S. teens spend more than eight hours a day on screens, and there’s growing concern over how social media may affect their mental health. Now, a new study has found that limiting screen time to about one hour a day helped anxious teens feel better about their body image and their appearance.

The study arose from the personal experience of Helen Thai, a doctoral student in psychology at MeGill University. “What I noticed when I was engaging in social media was that I couldn’t help but compare myself,” Thai says. She was well aware that social media posts often feature polished, airbrushed or filtered images that can alter (改变) appearances in an unrealistic way, but it still affected her negatively.

So, Thai and a team of researchers decided to test whether cutting time on social media platforms including Instagram, TikTok and Snapchat would improve body image. They recruited a few hundred volunteers, all of whom had experienced symptoms of anxiety or depression, which could make them vulnerable to the effects of social media. Half of the participants were asked to reduce their social media to 60 minutes a day for three weeks while the other half continued to use social media with no restrictions, which averaged about three hours per day.

The researchers gave the participants surveys at the beginning and end of the study, which included statements such as “I’m pretty happy about the way I look,” and “I am satisfied with my weight.” Among the group that cut social media use, the overall score on appearance improved from 2.95 to 3.15 on a 5-point scale. This may seem like a small change, but any shift in such a short period of time is striking, the authors say.

“The study is encouraging, but it only included people who had symptoms of anxiety or depression. It’s worth evaluating this approach with other groups, such as people with or at risk of eating disorders. It’s also possible that the benefits of cutting back could extend more broadly to anyone in this age group,” says Psychologist Andrea Graham, co-director of the Center for Behavioral Intervention at Northwestern University.

【推荐1】Recently, a team of researchers in Oxford University found that creating fuel(燃料)for planes out of CO2 could soon be a reality.

The process uses cheap iron as a material to catch CO2 from the air and turns it into fuel for planes. The researchers have described their discovery a “significant social progress” in how the plentiful greenhouse gas(CO2) is turned into fuel and its potential to make flying more environmentally acceptable.

Aviation(航空)is a large and growing contributor to the greenhouse effect. It contributes around 10 per cent of the UK’s greenhouse gas emissions(排放). Flying has as a result become an environmental battleground-with environmentalists strongly against expansion of air travel-for increasing CO2 emissions.

The UK, by law, is determined to get to “zero” carbon emissions by 2050, so a new form of carbon fuel must be found. The problem for aviation is that its fuel breaks down and gives off CO2and water, and both of them are sent out into the atmosphere.

However, the new technique would catch the gas in the air and create fuel, without the need of filling up with new fuel from the ground. CO2 is highly stable(稳定的), but the researchers managed to turn it back into fuel by using a chemical change powered by an iron-based material-at low temperatures-and adding hydrogen(H2).

Professor Edwards said the achievement could put Britain at a leading level of a new green industry. He expected it could increase production in two to three years and the team is in discussion with UK industries to set up a factory to put it into production. “Our plan is that the world can see that CO2 can be used as energy carrier to enable aviation to last.” he said.

【推荐2】In over 5,000 years of development, folk art has become a source of other forms of Chinese culture. However, the diversity (多样性) of cultural forms and the influence of foreign cultures have also brought challenges to Chinese folk art.

Chinese folk art has many types, including painting, calligraphy, embroidery, carving and paper cutting. It is hard to say how many kinds of folk art there are in the country. On the other hand, it is also hard to tell how many of them have disappeared. The situation is becoming more and more serious. Some kinds of folk art came to an end naturally, while others disappeared because there wasn’t enough protection. Isn’t it painful to lose so many kinds of folk art simply because of the absence of protection?

Folk art has played an important role in carrying forward history. For example, the blue printed cloth in Jiangsu Province has been a part of China’s printing technology for so long that, it is of great value to those studying China’s ancient science, technology, culture, folk custom and art.

Chinese folk art is drawing the attention of more and more foreigners with its unique charm and miraculous techniques (独特的魅力和神奇的技巧). Many people are worried about its protection and further development.

Then, who will be the protectors of Chinese folk art? It has to be the government, experts and scholars and even the whole of society. Though China has passed laws to protect its cultural relics, they don’t include the protection of folk art. Experts and scholars should go out among the people and find top artistic works still unknown to the world. Such protection also requires the support of the whole of society. Only when we gather forces from all sides can we protect Chinese folk art.

【推荐3】You drink diet soda enjoying the sweet taste without the guilt of calories. But scientists have long suspected a link between artificial sweeteners(甜味剂)and obesity in humans. A new study suggests that artificial sweeteners may not be as harmless as once thought. They may not only disturb the microbes(微生物)living in the bodies of humans, but some may even increase the risk of weight gain.

Every human hosts a unique group of microbes. The number of cells that make up this vast community, called microbiome(微生物群), is extremely large in the human body. It not only helps digestion but also protects against diseases. The disturbance to the microbiome occurs because artificial sweeteners, although zero calories for humans, serve as nutrients for some microbes, which then increase rapidly. This causes an imbalance in microbial populations that can lead to diseases.

In the study, scientists first chose 1,375 volunteers to see if they consumed artificial sweeteners in their daily lives. Then, they identified 120 volunteers who were not previously exposed to artificial sweeteners and gave them one of the four commonly used sweeteners—saccharin, sucralose, aspartame, and stevia for two weeks. After that, to test how artificial sweeteners affect the body’s ability to control the sudden increase of blood sugar after consuming sugar as part of meals, volunteers were monitored for blood glucose(血糖)levels after a test glucose drink.

The study showed that sucralose and saccharin pushed the body towards glucose intolerance, which, if sustained, can cause weight gain. However, aspartame and stevia did not affect glucose tolerance at the tested levels. “The study is the first to show that the human microbiome responds to artificial sweeteners. It’s also a convincing study to show how these sweeteners really are affecting the human body,” says Michael Goran, a professor at Children’s Hospital Los Angeles.

“This study provides evidence of both short-term harmful effects and long-term negative effects caused by artificial sweeteners,” David Katz, a nutrition specialist, says. “That does not mean artificial sweeteners should be replaced with sugar. Rather, alternative approaches to reducing sugar intake should be considered.”