Papa, as a son of a dirt-poor farmer, left school early and went to work in a factory, for education was for the rich then. So, the world became his school. With great interest, he read everything he could lay his hands on, listened to the town elders and learned about the world beyond his tiny hometown. "There's so much to learn," he'd say. "Though we're born stupid, only the stupid remain that way. " He was determined that none of his children would be denied an education.

    Thus, Papa insisted that we learn at least one new thing each day. Though, as children, we thought this was crazy, it would never have occurred to us to deny Papa a request. And dinner time seemed perfect for sharing what we had learned. We would talk about the news of the day; no matter how insignificant, it was never taken lightly. Papa would listen carefully and was ready with some comment, always to the point.

    Then came the moment—the time to share the day's new learning.

    Papa, at the head of the table, would push back his chair and pour a glass of red wine, ready to listen.

    "Felice," he'd say, "tell me what you learned today. "

    "I learned that the population of Nepal is .... "

    Silence.

    Papa was thinking about what was said, as if the salvation of the world would depend upon it. "The population of Nepal. Hmm. Well . . . . " he'd say. "Get the map; let's see where Nepal is. " And the whole family went on a search for Nepal.

    This same experience was repeated until each family member had a turn. Dinner ended only after we had a clear understanding of at least half a dozen such facts.

    As children, we thought very little about these educational wonders. Our family, however, was growing together, sharing experiences and participating in one another's education. And by looking at us, listening to us, respecting our input, affirming our value, giving us a sense of dignity, Papa was unquestionably our most influential teacher.

    Later during my training as a future teacher /1 studied with some of the most famous educators. They were imparting what Papa had known all along—the value of continual learning. His technique has served me well all my life. Not a single day has been wasted, though I can never tell when knowing the population of Nepal might prove useful.

    Our cities have never been denser, taller, or busier than they are now, and with that, comes the constant battle for land. But if we look at aerial images of any city center, we can quickly spot plenty of unused space — the rooftops.

    So what can we use this precious resource for? In a growing number of high-density cities, some of it is dedicated to recreation — everything from bars and pools, to soccer pitches and running tracks can now be found atop skyscrapers. But when a rooftop offers access to sunlight, there are two more obvious candidates for its use - agriculture and solar power.

    Green roofs have been growing in popularity for more than a decade, and in some cases, growing in scale too. Green roofs can provide a habitat for birds and insects in an otherwise hostile environment.

    Cities can be several degrees warmer than the surrounding countryside. Green roofs come with the added benefit of mitigating the dreaded urban heat island effect. Trees and green spaces can absorb shortwave radiation, and use it to evaporate water from their leaves — a kind of 'double cooling' effect.

    With food security and urban nutrition ever-higher on the agenda for the United Nations, there's also a worldwide movement of using green roofs for hyper-local food production. In regions with suitable climates, hundreds of different vegetables, fruits, and salad leaves can be grown on rooftops.

    But what about solar power? With so many cities now stopping using fossil fuels, and the costs of solar panels dropping dramatically, PV systems have become the 'go to' option for generating distributed power in built-up areas. And, even with standard commercial panels, the energy gains are dramatic. It is estimated that rooftop PV systems could generate almost 40% of electricity demands nationwide.

    There's no doubt that in both cases, a network of 'productive rooftops' could benefit the local community by supplying a portion of a necessary resource — either food or electricity — while also reducing their environmental burden. But is one better than the other?

    This was the question posed by researchers from MIT and the University of Lisbon in a recent paper in the journal Cities. Focusing on the rooftops of a mixed-use neighborhood in Lisbon, they carried out a Cost-Benefit Analysis. Starting with existing data on everything from installation costs and resources used, to carbon footprint and yield, they modelled the impact that each installation would have on the local community over a period of 50 years.

    And by looking at it that way, they concluded that for Lisbon, the use of rooftops for food production could yield significantly higher local value than solar PV energy generation. Of course, this is very site-specific. There is no one-size-fits-all solution to make cities more sustainable, and anyone who tells you otherwise is massively over-simplifying a complex issue. Now, all I hope is that some of those decision makers start using it.

    Many of us have reached in our pockets, feeling a vibration (振动), wrongly believing our mobile phones have just rung. The phenomenon even has a name: phantom (幻觉的) vibration syndrome—and found it is surprisingly common.

    Now scientists believe that we are so alert (警觉) for phone calls and messages we are misinterpreting slight muscle spasms (痉挛)as proof of a call. Robert Rosenberger, an assistant professor at the Georgia Tech Institute of Technology has studied the delusional calls. He said sufferers describe a vague tingling feeling which they think is their mobile phone indicating it has received a text message or call while on 'silent'. But when the device is retrieved, there was no one on the other end.

    Dr. Rosenberger said he found so many people say, "This happens to me, but I thought I was the only one. I thought I was odd." It seems that the syndrome particularly affects people at the beck and call of mobile phones or pagers. A 2010 study by Michael Rothberg and colleagues found that nearly 70 per cent of doctors at a hospital in Massachusetts suffered phantom vibrations. A more recent study of US college students found the figure was as high as 90 per cent.

    While the odd feeling is widespread, it does not seem to be considered a grave problem. Dr. Rosenberger said: "It's not actually a syndrome in a technical sense. That's just the name that's got stuck to it." He added," Only 2 per cent of people consider it a problem."

    While this phenomenon is widespread, the scientific community has not yet invested much effort in getting to the bottom of why we suffer phantom calls.

    Dr. Rosenberger said: "People are guessing it has something to do with nervous energy. The cognitive(认知的)scientists are talking about brain chemistry, cognitive pathways changing. But it's not like they have brain scans to go on." He said: "We have a phone call in our pocket all the time and it becomes sort of an extension of ourselves. We have this sort of readiness to experience a call. We feel something and we think, OK, that could be a call."

    I took a journey to New York, US several months ago. It was the first time I had been abroad. It was also the first time I had taken a trip by myself. I had great enthusiasm and high hopes, and I wasn't let down.

    It's hard to describe how I felt when I arrived at the airport in New York. Looking at people of different races and nationalities passing by and hearing different languages all around me, I couldn't say anything for a long time. I had never understood the cultural diversity of the US so clearly and closely before.

    The following days were even more impressive. We integrated(融入)into the forest of concrete and cement(混凝土和水泥). We waved to the Statue of Liberty; we looked down at the busy island of Manhattan; we looked at well-known universities—Harvard of ancient Egypt.

    Then we visited some well-known university—Harvard, Yale, Princeton and Columbia—each with its own appealing and time-honored history. But what all these universities have in common is their peaceful academic atmospheres witch you could feel everywhere. I was impressed by the libraries, decorated just like cathedrals(教堂), and the laboratories just next to the classroom. My dream is to return to those places as an international student.

    Finally came our destinations—the Model United Nations conference at the University of Chicago. Students from various countries arrived to act as United Nations delegations and share their opinions about global issues.

    As a non-native speaker, I felt that competing against native speakers was a very tough task. But it was also a rare change to improve my English and I couldn't throw it away. With perseverance and devotion. I got used to talking to other delegations naturally. Although I didn't win any awards, the chairman praised me at the closing ceremony for my excellent performance. That made me feel really proud.

    This trip brought me unforgettable and valuable experiences that will benefit me forever.

Liu Yexi has taken Douyin by storm. As of Nov 17, the virtual idol, who performed on the social media platform on Oct 31, had only released two short videos but attracted over 5 million followers. 

Different from other virtual idols, Liu is defined as a "virtual beauty vlogger". In her first video, Liu is doing makeup with an eye brush while dressed in a traditional Chinese costume. 

When she turns around, the onlookers are terrified, except one boy. Then Liu slightly brushes the boy's eyes, allowing him to see the fantasy world in her own eyes. The internet users marveled(使...惊叹) at its storyline, science-fiction elements and special visual effects with cyberpunk style. Liang Zikang, the CEO of the production team, told China Newsweek that the team spent two months making the video. 

Liu's instant popularity online further reflects that the virtual idol industry in China has been booming. There are over 32,400 virtual idols that have opened accounts on video-sharing platform Bilibili in the past year, seeing a year-on-year rise of 40 percent, Chen Rui, the CEO of Bilibili, said in a speech. 

"Compared with real idols and stars, the virtual ones seem to be more approachable for fans," Shine News noted. Additionally, these virtual web celebrities(名人) won't have scandals(丑闻). 

As more young people are fascinated by these virtual figures, their commercial(商业的) value has been on the rise. Generally, they earn money by online concerts, livestreaming and related products. For example, Luo Tianyi, a well-known virtual singer, cooperated with livestreamer Li Jiaqi to promote goods in 2020. 

Therefore, some people are wondering whether they will replace real humans. "These socalled virtual idols have real human teams to back them up and control them. They are not really virtual." Ding Daoshi, an independent analyst in the internet sector, told the Global Times. The real virtual idol will come when artificial intelligence achieves a new level of selflearning and self-training and then interacts with others, he added.

It's breathtaking to watch the delicate spring wildflowers come out from their blanket of leaves, bloom, develop and disperse (传播) fruit, all in a matter of a few short days or weeks.

Although they look fragile, these are tough little plants, each focusing its efforts on spreading its species. They have evolved to have a wide range of flower structures and colors, some with fragrances, attracting many different insect species to assist them in pollination (授粉).

There is one strategy that a surprising number of spring blooming native plants have evolved in common: seed dispersal by ants. As many as thirty percent of the spring flowering plant species in the forests of eastern North America have evolved to take advantage of this situation to benefit themselves. These species have evolved to provide food attached to their seeds to encourage ants to disperse those seeds. This food, called an elaiosome（油质体）, is a specialized fat body whose chemical composition more closely matches that of the insects that ants prefer than it does that of a seed.

When a fruit opens to disperse its seeds, the elaiosomes are an instant attraction for ants. They take the seed with its attached elaiosome back to their nests for consumption there, but they just eat the elaiosome, their preferred food, and dispose of the seed on their trash pile. This tends to be an environment that is rich in nutrients, and will benefit the growth of the new plant. Just to make sure the ants don't eat the seeds in addition to the elaiosome, some plant species have hard seed coatings that ants can't really bite through.

This evolutionary adaptation is somewhat similar to the strategy of plants that have evolved to surround their seeds with fleshy fruits to attract birds to assist them with seed dispersal. Given the fact that there are fewer birds available in early spring to help with seed dispersal, it makes sense that the early blooming plants evolved to partner instead with the ants for this service.

Did you ever wonder how your Spring Beauty managed to pop up in new locations in your lawn or garden? Thank an ant!