Crown shyness(树冠羞避) is a mysterious natural phenomenon in which the crowns of some tree species do not touch each other, but get separated by a gap clearly visible from ground level. The effect usually occurs between trees of the same species, but has also been observed between trees of different species.

    There are many theories going around, most of which make sense, but no one has been able to prove without the shadow of a doubt why some trees avoid touching each other.

    In his 1955 book Growth Habits of the Eucalypts, Australian forester M.R. Jacobs writes that the growing tips of the trees are sensitive to abrasion(擦伤), which results in crown shyness phenomenon. This theory was also supported by Dr. Miguel Franco. Some experiments have shown that if trees displaying crown shyness are artificially prevented from swinging in the wind and touching each other, they gradually fill up the gaps between them.

    But while the above theory is arguably the most widespread, it's certainly not the only one. Some scientists have suggested that crown shyness is a mechanism to stop the spreading of leaf-eating insects. These pests have been known to work together and create structures that extend up to 10 cm off of tree branches in order to reach other plants, so the gaps are the trees' natural defense method.

    One Malaysian scholar studied many trees, but found no traces of abrasions, despite their clear crown shyness. Instead, he suggests that the growing tips of the trees were sensitive to light levels and stopped growing when they got too close to other trees. Plants are able to sense how close they are to other plants and in order to get more light, they give off some chemical element to stop other trees from growing too close.

    Whatever the reason, one thing is for sure: plants are more intelligent than people used to think.

    An international group of coffee experts has considered Ethiopia's coffee as the best in the world. Coffee is a top export of the country. But at home, it is seen as national pride. Ethiopians feel good about their coffee, and enjoying a drink with friends is a long tradition.

    International coffee experts travel the world to find the best coffee. They keep returning to Ethiopia. Some people say the climate produces quality beans. Morton Wenner is a coffee importer. He said, “Ethiopia has different ancient types of coffee. They are planted in places with perfect soil, perfect altitude, and climates that are really suitable for coffee processing, such as drying and things like that.”

    Finding the best quality beans is often an issue of taste. The process is known as cupping — tasting and comparing coffee from different roasted beans, grading and then pricing them.

    But before international experts come to taste, coffee beans are studied in small coffee laboratories. Helen Assefa, a lab technician, describes the process, “When the coffee comes to the lab, we assess its quality first by recording the details. Then we weigh the wetness level and screen the beans for analysis. After that we polish the coffee beans and taste the samples. At the end we check for imperfect beans.”

    Ethiopia is making big profits on its coffee reputation by exporting coffee to more than 120 countries. The country has an export income of more than $840 million a year. But not all the best coffee leaves Ethiopia. Forty percent of the coffee grown in the country stays there. It remains an important part of everyday life at work, at home and at ceremonies just to celebrate that special cup.

    There is a cry of anger, and a tennis racket crashes to the ground. Jake, age 7, has just lost another match and is now in tears beside the court. His sister Sally, just one year older, looks at her mother and rolls her eyes: it is hard to enjoy winning when this keeps happening. It is not an unusual situation, and it is one reason why many people argue that competition is bad for children. However, the truth is that competitive games are a valuable preparation for adult life.

    Games with winners and losers give children the chance to experience life's ups and downs. Take Jake, for example. Even though he is unhappy now, he will probably be smiling and laughing with his sister in a few minutes, just like the last time this happened. Gradually, he will learn that the world does not end when you lose a game. Eventually, he may even be able to lose with a smile on his face. This is an important lesson. Not everything in life goes the way you would like, and it is important to know how to handle disappointment when it occurs.

    Children who participate in competitive games develop qualities that allow them to succeed in the complex world of adult life. For example, one of the missions of the Youth Olympic Games is to inspire young people to adopt the Olympic values, which include striving, determination and optimism. Competition creates a desire to do better. Children have to learn to succeed in a competitive atmosphere in order to take advantage of opportunities in the future. Although it is possible to win by chance occasionally, people who win and keep winning work very hard to achieve their success.

    On the negative side, there are those who will say that competition actually encourages some values, which does happen. It is common to see sports competition in which the desire to win has replaced the desire to have fun. You may even see very young children playing violently—like the superstars they see on TV. While the bad behavior of young athletes is troubling, the problem is not the competition itself. In reality, the blame lies with the professional players who are bad role models for these children. In fact, a recent study of young athletes by the school of Physical Health Education at the University of Wyoming showed an improvement in mood after exercise, athletes were less depressed or tense.

    Of course, there are parents who argue that children of Jake's age are too young to handle the pain of losing. But whether we like it or not, adult life is very competitive, and keeping children away from competition does them more harm than good. If children do not learn how to compete, they will be defeated by people who can. It is an unfortunate fact of life: whether ten or a hundred people want the same job, there can be only one winner. Wouldn't you want your child to be that person?

    Six months after a Chinese scientist was widely condemned for helping to make the world's first gene­edited babies, he remains out of public view, and new information suggests that others may be interested in undertaking the same kind of work outside the United States.

    A clinic in the United Arab Emirates city of Dubai emailed scientist He Jiankui to seek training in gene editing, Stanford University bioethicist Dr. William Hurlbut said ahead of a speech Tuesday at the World Science Festival in New York.

    Hurlbut, whose advice He often sought, said He told him that scientists from multiple countries and families with inherited health problems had messaged support and interest in altering the genes of embryos(胚胎)to prevent or treat disease. Hurlbut gave The Associated Press the email the Dubai clinic sent to He in December but decided to hide the clinic's name.

    "It reveals what eagerness there is out there to use this technology" and the need "for some sort of practical governance" of it, Hurlbut said.

    Jennifer Doudna, a University of California, Berkeley, co­inventor of the CRISPR gene­editing tool that He used, said that she also has heard of others who want to edit embryos.

    "I think they're entirely credible," she said of such reports. Doudna, who was also a speaker at the New York festival, said the field needs to focus on setting specific principles for how and when such work should proceed.

    "The technology is frankly just not ready for clinical use in human embryos," although research should continue, she said. Doudna is paid by the Howard Hughes Medical Institute, which also supports AP's Health and Science Department.

    Scientists and policy leaders have been debating how to set international standards or controls since He claimed in November that he had altered the genes of twin girls at conception(怀孕)to try to help them resist possible future infection with the AIDS virus.

    Editing embryos is outlawed in many countries because it risks damaging other genes, and the DNA changes can be passed to future generations. Many scientists have condemned He's work, and attention has fallen on other scientists who knew or strongly suspected what He was doing.

    HANGZHOU — Chinese internet giant Alibaba on Tuesday opened a hotel loaded with artificial intelligence (AI) and robots, automating a series of procedures like check­ in, lights control and room service.

    FlyZoo Hotel, opened in Hangzhou, capital of East China's Zhejiang province, where Alibaba is headquartered, is known as the company's "first future hotel". Customers can check into the hotel by simply scanning their faces. The facial recognition system installed in the hotel also enables customers to use their faces as key cards to open doors and access another hotel service. Users can also control the lights, televisions and curtains in the room via Alibaba's voice­activated digital assistant, while robots are deployed to serve dishes, cocktails and coffee. Hotel bookings and check­out can also be done with a few clicks on mobile through an app. "The AI­based solution can help customers save time and relieve hotel employees from repetitive work," said Wang Qun, CEO of FlyZoo Hotel. The hotel is the latest example of Chinese tech companies' attempt into traditional industries such as the hotel industry.

    E­commerce giant JD.com announced in October its strategy to put smart home and electronic devices sold on its platform into hotels, in an effort to improve online sales.

    In July, Baidu teamed up with Intercontinental Hotels Group in Beijing to allow guests to use its voice­ controlled assistant to adjust room temperature and order room service at ease.

    Before that, social media giant Tencent introduced QQfamily, a similar tech solution for hotel operators, in the southern city of Zhuhai last year.

    "We want to install a 'smart brain' for hotels," said Wang. "In the future, we will continue to make hotels smarter and more automated, as well as create more personalized experiences for consumers."

If you've ever seen a sparrow steal your dog food or a crow open a garbage bag, you get a sense of that some birds have learned to take advantage of new feeding opportunities—a clear sign of their intelligence. Scientists have long wondered why certain species of birds are more innovative than others, and whether these capacities stem from larger brains or from a greater number of neurons（神经元） in specific areas of the brain.

It turns out that it's a bit of both, according to a recent study by an international team that included members from McGill University published in Nature Ecology and Evolution.

The researchers used a new technique to estimate the number of neurons in a specific part of the brain called the pallium in 111 bird species. The pallium in birds is equal to the human cerebral cortex（大脑皮层）, which is involved in memory, learning, reasoning, and problem-solving, among other things. When these estimates about neuron numbers in the pallium were combined with information about over 4,000 feeding innovations, the team found that the species with the higher numbers of neurons in the pallium were also likely to be the most innovative.

"The amount of time chicks spend in the nest as their brains develop might also play acrucial role in the evolution of intelligence," says McGill University Emeritus Professor Louis Lefebvre who spent more than 20 years gathering examples of feeding innovations. "Larger species of crows and parrots, which are known for their intelligence, spend longer in the nest, which allows more time for the brain to grow and accumulate pallial neurons."

The results of the study help to deal with previously opposed views of the evolution and significance of brain size and show how a life-history perspective helps to understand the evolution of cognition.