【推荐1】Warming seas across the globe are endangering coral reefs, a key ecosystem that supports marine life to live and thrive. As a possible way to preserve them from extinction, scientists have recently frozen and revived groups of adult corals for the first time, according to a recent study.

Freezing biological materials, or “cryopreserving” them, refers to keeping them in a deep freeze for long periods without affecting the cell’s viability (活性), according to the Science Times website. This method usually cools them to very low temperatures, commonly to -196 ℃. Since cells would normally die at such a low temperature due to the formation of ice inside, scientists need to monitor the freezing rate and choose the freezing medium carefully.

Researchers in the US experimented with freezing pea-sized pieces of a common coral in Hawaii. After removing the microorganisms on the corals, they sealed the corals in metal containers filled with a chemical solution that partially dehydrated them and helped control ice growth. When the corals reached a temperature of around -200 ℃, the remaining water in the corals solidified into a glassy form. The corals were still alive, with their life-driving functions becoming extremely weak. After being cryopreserved for a few minutes, the researchers pulled the corals out and placed them in warm water. In two minutes, they started consuming oxygen — a sign of them staying alive.

Previously, researchers had already successfully cryopreserved coral larvae (幼虫), according to a study in 2018. However, the larvae can only be collected when corals lay eggs, which happens just a few nights each year. “That’s putting a lot of eggs in one basket, ” US marine scientist Li za Roger told Science News. This breakthrough offers more hope to the world’s corals, said Roger. However, there’s more work to be done. A few days after unfreezing, the corals became “stressed out” from the process and were killed by the bacteria they normally live in harmony with. The researchers are working on using antibiotics to help them survive for a longer period of time.

【推荐2】In 2008, a study was conducted in Hong Kong to find out why some people appeared to be better at public speaking. Three hundred people who were employed in jobs that require an advanced level of public speaking skills were interviewed.     1     The results of the study showed that 77% of the participants reported having parents that encouraged them to ask Questions and express their opinions from a young age. And 85% answered that their parents had repeatedly exposed (使接触) them to a variety of good “public speaking” experiences at home.     2    

In another study to determine the causes of fear of public speaking, 70% of the participants said they had not had any public speaking opportunities at home. In addition, 18% of the participants had been given such opportunities, but these had resulted in a loss of confidence.

    3     His parents had arranged for him to present his school project about earthquakes to his cousins. As an outgoing boy, he was eager to show off all his hard work, until he forgot a sentence and started to stutter (结巴). His cousins began to laugh at him, and instead of his family encouraging him to continue with his presentation, his father told him to stop. The stress of this incident and the feeling of being rejected continued to school, where he started struggling with his words and went red like a sunset every time he had to speak in front of an audience.

From these studies, we can see that the way parents handle their children’s communication efforts and the children’s future attitudes towards public speaking can be linked.     4     But rather they grow to be anxious about it because of terrible experiences of outside influences. Yet this does not mean they have no control over their fear — because they do.

【推荐3】Maybe you are familiar with scenes in movies where a pilot has encountered(遇) an issue mid-flight and you hear him shout “Mayday，mayday，mayday”.

But what does “mayday” mean? “Mayday” is an internationally recognized distress call（求救信号），mostly used by pilots and boat captains. The signal can be sent out by any channel by radio communication.

This emergency call originated in the 1920s. At that time, the standard distress call was “SOS” and was typically used by navy captains. The message was sent in Morse code by telegraph. In Morse codes,“SOS”is three dots（点），three dashes（线）and three dots. The signal was unmistakable. However, aircraft pilots use radio calls, so sending out “SOS”could be misheard as other letters, such as “F”.

Frederick Stanley Mockford, a radio officer at Croydon Airport in London, was asked to think of a word that would indicate distress. Because of the amount of the flights that flew between Croydon and Paris, he chose mayday, as it sounds similar to the French word “m’aider”, which means “help me”.

Facing a threatening situation, pilots are required to repeat the signal three times in case of radio interference（干扰）or loud background noise. If the pilots don’t get a reply within two minutes, they should repeat it. Once they receive a reply, more information, including the code of the flight, their current situation and the number of people on board should be reported. Sometimes pilots are directed to a nearby airport or location where they can make an emergency landing. While mayday signals indicate a life-threatening situation, they do not always end in fatalities（死亡）.

Despite dangers, air travel is still the safest means of transport.

【推荐1】The internet isn't always a happy place. But there are groups trying to change that. Kuakuaqun, or “praising group” on Wechat, in which people send out compliments and positive messages, are becoming popular among university students in China.

Praising groups have been founded by students from several universities, such as Fudan University, Communication University of China, Huazhong University of Science and Technology. People can even buy memberships of such groups on online platforms like Taobao. Once admitted, they make complimentary comments about each other and even ask to be complimented on particular things.

The praising groups come at a time when the mental health of young Chinese is getting attention. As young Chinese seek company and confidence, the praising groups meet a lot of psychological needs. “The group allows me to see the good qualities in myself that I often overlook and look at the bright side of everything. Kindness from strangers can help me feel much better,” Tian Jiayin, 22, told China Daily.

The popularity of chat groups is also a reflection of Chinese culture, reported Global Times. As many young Chinese are raised to be modest, it’s uncommon for them to openly seek and give praise. As a result, they desire compliments as they grow up. “If the kids got more praise from parents and teachers, their desire for praise wouldn't be so strong,” said Dai Ji, a psychologist from Hunan University of Commerce.

But Chen Kan, a psychologist from Fudan University, warned that members of praising groups should be cautious about giving or receiving praise. “The biggest risk is the constant emphasis on the ‘false self’, which makes it harder to see the ‘true self’,” she said.

【推荐3】As the new year approaches, crowds around the world may be expecting whizzes and bangs to light up the sky. The appeal of fireworks could fade out with the growing use of drones (无人机)for light shows, though.

Ollie Howitt, a leader of Sky Magic, which used a team of 300 drones to create a display for London’s new year celebration last year, said the demand had increased dramatically. “We do think it’s going to be something ever-eye catching rather than being a short-lived sort of fashion people have suddenly got interested in. Drones are reusable and there’s no fallout. In that sense, they’re a very good, sustainable option.” she said.

But not everyone agrees. A spokesperson from the British Fireworks Association said drones could also pose environmental problems. “Drones have less an impact on the environment, but we have serious concerns about electrical demand and the use of lithium batteries which are known not to be much that ‘green’,” they said.

An RSPCA spokesperson said that while drones tried to reduce the impact of displays on animals, there were downsides. “Drones are not without their own negative issues such as scaring horses or crashing into birds, and can cause disturbance to animals and members of the public. Therefore, it’s important for their effects to be fully considered and measures taken to minimize the chance of accidents.” they said.

Some express the opinion that the use of fireworks and drones don’t conflict with each other. The sight, sound and gunpowder smell of fireworks will always provide its own unique thrill.

“We find fireworks work really well when teamed up with drones. But we don’t really see it as a one-replacing-the-other at all. We feel as if it’s merely another tool to light the sky.” said Howitt, noting that while fireworks give a loud, emotive, big performance, drones offer the chance to tell stories in the sky by using a series of images.