Every animal sleeps,but the reason for this has remained foggy. When lab rats are not allowed to sleep, they die within a month.{#blank#}1{#/blank#} 

    One idea is that sleep helps us strengthen new memories. {#blank#}2{#/blank#} We  know that, while awake,fresh memories are recorded by reinforcing (加强)connections between brain cells, but the  memory processes that take place while we sleep  have been unclear.

    Support is growing for a theory that sleep evolved so that connections between neurons(神经元)in the brain can be weakened overnight, making room for fresh memories to form the next day.  {#blank#}3{#/blank#}

    Now we have the most direct evidence yet that he is right. {#blank#}4{#/blank#} The synapses in the mice taken at the end of a period of sleep were 18 per cent smaller than those taken before sleep,showing that the connections between neurons weaken while sleeping.

If Tononi's theory is right, it would explain why, when we miss a night's, we find it harder the next day to concentrate and learn new information —our brains may have smaller room for new experiences.

    Their research also suggests how we may build lasting memories over time even though the synapscs become thinner. The team discovered that some synapses seem to be protected and stayed the same size. {#blank#}5{#/blank#}  “You keep what matters,” Tononi says.

    ID systems are used as a means for people to prove their identity, as a means of access control, or for many other situations. ID cards also contain a lot more information than simply the name of the holder. All ID cards contain information that is relevant to the institution that released them, so there is no single model that applies to all ID cards.

    Different institutions have different rules when it comes to ID cards, and ID cards used by students, in universities, will not have the same security features as those used in the military, for example. The more important the institution is, the more important the security is, and the more security features will be used to prevent duplication(复制) of an ID card.

    Anyone with a printer that can print ID cards can duplicate in ID card, if it does not have any security measures. There have been lots of cases, especially in low security institutions, where ID cards have been duplicated and this was not noticed, since the person holding the card usually flashed it when it was requested, and that was not enough to notice that it is a fake.

    That may not be extremely important when it is simply a case of a student trying to enter the campus of another university, but it can be of vital importance if it happens in a military institution. Checks in military institutions are much stricter and the personnel checking the card are always trained to spot fakes in a short amount of time.

    Some may think that creating an ID card is extremely difficult, but it is not. All it takes is a special printer that can print ID cards, a model and a photo ID. The fact that such printers can be freely ordered online has raised security issues with lots of companies and institutions, and most have decided to either create their own ID cards, or simply use more advanced security features that regular home-users do not have access to. This includes magnetic stripes(磁条), chips, barcodes(条形码),and other methods. This does increase the cost of the card per person, so the total cost of the cards increases based on the number of employees the company has, but it also reduces security risks to a minimum.

    So ID systems, as basic as they seem, are an excellent security measure for any institution. To ensure that the IDs look good and function properly, the company that handles the card printing services should be top-class. Trying to save some money by choosing a cheaper provider is not really wise. While some companies offer bonuses for large orders, if the quality provided is not of the highest standard, it is not worth it.

Do you think you could learn a language in an hour?

    We know, we know! We would expect you to be skeptical. It's ridiculous to think you can learn a language in 60 minutes. You wouldn't even get through the As in a bilingual dictionary in that amount of time! Best-case situation: in an hour, most of us could probably stuff a few words and ready-made phrases into our short-term memory (with a high likelihood of forgetting it all by the following day). Accomplishing anything more than that in one hour? Impossible. Unless…

    We posed the one-hour language challenge to four polyglots(通晓数种语言的人) who are experts on how to study languages. To keep the challenge from becoming completely impossible, we gave them a bit of a break: to learn Romanian in one hour. Why Romanian? Because it's a Romance language and shares many similarities with the languages that the polyglots already know: French, Spanish, Italian, Portuguese. And to make sure their hour of learning was as effective as possible, all of them were assigned a personal Romanian tutor to help coach them on their way to success.

    Although each polyglot has a different technique for picking up and remembering a new language, all four methods offer valuable insights to anyone, from casual learners to hard-core language enthusiasts.

Alex Rawlings — UK

    "I'm a bit nervous. This is probably the craziest language-learning thing I've ever done, but learning languages has always been about fun. I expect that, after this, I'll be prepared to have a simple chat over a coffee in Romanian. Is that reasonable?"

    Method: Learn the verbs first

    With only an hour until he had to start demonstrating his grasp of Romanian, Alex knew he had to start talking quickly. He chose to focus first on commonly used verbs and how to conjugate（动词变形） them. Once he had some verbs down, he could start collecting nouns from his tutor and plugging them in to make more interesting and relevant sentences.

Luca Lampariello — Italy

    "Every time I have a conversation with native speakers, it really motivates me. Human contact is really important when learning a language."

Method: Start speaking right away

    Speaking doesn't mean speaking perfectly. Speaking even a little bit is a huge confidence boost. When you can say something in a new language and people actually understand you, it's very motivating. Yes, you'll make mistakes, but you'll also learn faster than if you try to get it all perfect in your head first.

Michael Youlden — UK

    "We all speak a variety of Romance languages which I think will help us get into Romanian quickly."

Method: Write everything down

    Language learning is about recall; there's no use learning something if you don't remember it. Speaking new words aloud is very important, but so is writing them down — after all, words exist as sounds and in written form. Taking notes is a proven way to put new vocabulary and grammar into your memory. Writing supports memorizing which supports speaking... it's a cycle. Plus, you have an easy reference when you want to review what you've learned.

Matthew Youlden — UK

    "I'm going to look for the patterns and similarities with languages I already know. We won't be able to speak fluently after an hour of study, but we should be able to get by with some basic vocabulary and phrases."

Method: Look for cognates

    Cognates are words in different languages that look and sound similar and have the same meaning, due to a common origin. Almost every language combination contains cognates (even if two languages aren't seemingly related), but languages from the same language family have many more. Whichever language you are learning, identify the familiar words and then use them to anchor the new words that aren't so familiar. To use English as an example, because it's a sort of Germanic-Romance hybrid, English already has many words that cognate with German, Dutch and Swedish on one hand, and on the other hand it also has lots of words that cognate with French, Spanish, Portuguese, Italian and, of course, Romanian!

    Learn a language with courses designed by the experts. Start here, today!

    Pick a language to learn. German, Spanish, Italian, French, Portuguese, and Swedish.

Quiet Virtue: The Conscientious

    The everyday signs of conscientiousness (认真尽责)—being punctual, careful in doing work, self-disciplined, and scrupulous (一丝不苟的) in attending to responsibilities—are typical characteristics of the model organizational citizen, the people who keep things running as they should. They follow the rules, help out, and are concerned about the people they work with. It's the conscientious worker who helps newcomers or updates people who return after an absence, who gets to work on time and never abuses sick leaves, who always gets things done on deadline.

    Conscientiousness is a key to success in any field. In studies of job performance, outstanding effectiveness for almost all jobs, from semi-skilled labor to sales and management, depends on conscientiousness. It is particularly important for outstanding performance in jobs at the lower levels of an organization: the secretary whose message taking is perfect, the delivery truck driver who is always on time.

    Among sales representatives for a large American car manufacturer, those who were most conscientious had the largest volume of sales. Conscientiousness also offers a buffer (缓冲) against the threat of job loss in today's constantly changing market, because employees with this quality are among the most valued. For the sales representatives, their level of conscientiousness mattered almost as much as their sales in determining who stayed on.

    There is an air around highly conscientious people that makes them seem even better than they actually are. Their reputation for dependability influences managers' evaluations of their work, giving them higher evaluations than objective measures of their performance would predict.

    But conscientiousness in the absence of social skills can lead to problems. Since conscientious people demand so much of themselves, they can hold other people to their own standards, and so be overly judgmental when others don't show the same high levels of model behavior. Factory workers in Great Britain and the United States who were extremely conscientious, for example, tended to criticize co-workers even about failures that seemed unimportant to those they criticized, which damaged their relationships.

    When conscientiousness takes the form of living up to expectations, it can discourage creativity. In creative professions like art or advertising, openness to wild ideas and spontaneity (自发性) are scarce and in demand. Success in such occupations calls for a balance, however; without enough conscientiousness to follow through, people become mere dreamers, with nothing to show for their imaginativeness.

AlphaZero--an Updated Model of AI

    Soon after Garry Kasparov, the former world chess champion, lost his rematch against IBM's Deep Blue in 1997, the short window of human-machine chess competition slammed shut forever. Unlike humans, machines keep getting faster, and today a smartphone chess app can be stronger than Deep Blue. However, as people see with the new AlphaZero system, machine dominance has not ended the historical role of chess as a laboratory of cognition.

    Much as airplanes don't flap their wings like birds, machines don't produce chess moves like humans do. Based on a generic algorithm (算法), AlphaZero incorporates deep learning and other AI techniques like Monte Carlo tree search to play against itself to develop its own chess knowledge. Unlike the traditional program Stockfish, which employs many preset evaluation functions as well as opening and endgame moves, AlphaZero starts out knowing only the rules of chess, with no preset human strategies. In a few hours, it plays more games against itself than have been recorded in human chess history. It teaches itself the best way to play, reevaluating the relative values of the pieces. It quickly becomes strong enough to win 28, draw 72, and lose none in a victory over Stockfish. Since AlphaZero can program itself, this superior understanding allows it to outclass the world's top traditional program despite calculating far fewer positions per second. It's the typical example of the cliché, "work smarter, not harder".

    AlphaZero shows that machines can be the experts, not merely expert tools. Explainability is still an issue—it's not going to put chess coaches out of business just yet. But the knowledge it produces is information humans can learn from. AlphaZero is surpassing humans in a profound and useful way, and researchers are working on transferring the knowledge acquired from AlphaZero to other fields.

    Machine learning systems aren't perfect. Even though great progresses have been achieved, AI algorithms are still struggling on open problems such as computer vision, natural language understanding... There will be cases where an AI will fail to detect exceptions to its rules. Therefore, as Kasparov writes, "We must work together to combine our strengths. I know better than most people what it's like to compete against a machine. Instead of raging against them, it's better if we're all on the same side."

Kite Power

The search for new, clean energy sources has occupied the attention of scientists and politicians for years. One common resource for green energy is the wind. A new twist on this old resource could cause the energy output of wind-power plants to rise dramatically.

Standard wind-power plants rely on fixed support and generally can only reach a height of 200 meters or so. Higher than that, winds tend to be stronger and more persistent.{#blank#}1{#/blank#}

Delft University of Technology in the Netherlands and Karlsruhe University of Applied Sciences in Germany have formed a kite-power research group. The group is working to develop kites with inflatable (可充气的) wings connected to electrical gencrators on the ground. The research group's goal is to design a kite that can operate on its own for 24 hours. Research has begun，but many challenges remain，including making the generators more efficient and perfecting the automatic flight control and the structure of the kites.{#blank#}2{#/blank#}

Meanwhile, in Italy, researchers are working in a similar power generator that relies on kites. When the generator, called KiteGen, senses the wind blowing, kites are released from the ends of poles with high-resistance cables to control their height and angle. These cables are able to move the kites if the system senses incoming objects such as planes, helicopters or even individual birds. The kites themselves are light, tough and able to reach fairly high altitudes. They form a circular shape in the wind, which sets the core of the generator in motion, producing electric current. KiteGen has the potential to be very cost-effective in the long run.{#blank#}3{#/blank#}

The plant also requires relatively little space, which makes it ideal for cities and means that multiple plants can be set up to provide even more energy.

{#blank#}4{#/blank#}In the future, it may be an efficient, cost-effective addition to the other sources of energy we use, or even a replacement for some of them.

A. But the challenge is figuring out how to collect the energy from those winds.

B. Kite power has the potential to greatly improve on current wind-power strategies.

C. Wind at these altitudes (海拔高度) is stronger and steadier0 which increases productivity factors of the system to about 60%.

D. Its plan is to build a kite power station using technology that can collectively generate (产生) large amounts of energy.

E. Nevertheless, they successfully demonstrated that their kites could operate automatically at an altitude of up to 700 meters.

F. After the initial cost of designing and setting up the plant, little additional investment will be necessary, apart from standard maintenance.