How did people in ancient China change their luck? Most of them would take the exam, Keju, which began during the Sui Dynasty and lasted for 1,300 years before it was ended in the Qing Dynasty.

    Keju, the early “gaokao”, played a very important role in choosing qualified persons to work for the king.

    The Keju exams were mainly based on classical literature(文学) and philo- sophy. Poetry was very important in earlier Keju exams, and later Keju focused more on writing.

    All candidates had to write an article explaining ideas from those books, which was called Eight Part Essay. Two sentences were required at the start of the article, about the main idea of the title, which was called “to clear the topic”. The exams also focused on more practical matters.  

    Most candidates in ancient China had to go a long way to the capital city for the exam. As transportation in ancient times was not developed, they usually went to the capital on foot, and some took several months to reach the capital.

    The exam was held once every three years and it was made up of four levels: the county examination, provincial examination, academy examination and palace examination. Candidates had to first pass one level in order to take part in the next level. Each examination would take from one to three days to finish, and they were locked in a small room and received cold meals.

    On the exam day, candidates had to first go through safety check. They had to let their hair loose so that it could be checked and their trouser legs, shoes and socks, even bottoms were also checked.

    Camels are large animals living in dry areas. There are two species of camels; the Arabian camel with a single hump(驼背) from the dry desert areas of West Asia, and the Bactrian camel with two humps from Central and East Asia. Camels are over 7 feet tall and weigh over 1,600 pounds. They will live up to 40 to 50 years. Most camels are domesticated(驯化) and fed by people. Camels are plant-eaters．

    Camels are very strong animals with wide, padded feet. They have thick leathery pads on their knees and chest. Camels have nostrils(鼻孔)that can open and close, protecting them from the desert environment. Bushy eyebrows and two rows of long eyelashes protect their eyes from sand. Their mouth is extremely tough, allowing camels to eat thorny(带刺的)desert plants. Their widened feet help them move without sinking into the sand. Their thick coats reflect sunlight, and also protect them from the intense heat from desert sand. Their long legs help by keeping them further from the hot ground．

    Camels can go without food and water for 3 to 4 days. They do not store water in their humps as is commonly believed．The humps are actually a container of fat. Camels are incredibly well-adapted to their environment. When conditions heat up, camels can increase their own body temperature, which prevents sweating and therefore water loss. They may not sweat at all during the day．

    Camels are sometimes called“ships of the desert”because people ride them around the hot, dry deserts of the world．However, the number of camels is becoming smaller for various reasons．

    Scientists have found that human eyes are more likely to be damaged by UV rays while skiing in the snow-covered areas than sitting on the beach, according to a report by the UK newspaper.

    The researchers at Kanazawa Medical University, Japan and American company Johnson conducted the study together. They looked at the effects of light reflection on newly fallen snow on a ski trail in Ishikawa District, northern Japan. They compared the results with the levels of UV rays on a sand beach in southern Japan's Okinawa District.

    They found that on the beach, eyes are exposed to a daily 260 kilojoules (千焦耳) of UV a square meter compared to 658 kilojoules  in snow-covered areas.

The findings are supported by the Japan Meteorological (气象的) Agency. According to the agency, the reflection rate of UV light on beaches is often between 10 and 25 percent, compared to 80 percent in the new snow areas. The amount of light increased 4 percent with a 300-meter rise in height.

    Most of us know that UV rays can harm the skin. That's why we wear sunscreen on our skin before we get out in the sun. But many of us may not realize that UV rays are also harmful to the eyes.

    If your eyes are exposed to large amounts of UV radiation over a short period of time, you may experience a kind of sunburn of the eye, which is harmful. Your eyes will become red and feel a strange feeling. They may be sensitive to light. Fortunately, this is usually temporary and seldom causes permanent damage to the eyes.

    Long-term exposure to UV radiation, however, can be more serious. Scientific studies and researches have shown that exposure to small amounts of UV radiation over a period of many years increases the chance of eye damage, which could lead to total blindness.

    In the United States, when one becomes rich, he wants people to know it. And even if he does not become very rich, he wants people to think that he is. That is what “keeping up with the Joneses” is about. It is the story of someone who tried to look as rich as his neighbors.

    The expression was first used in 1913 by a young American called Arthur Momand. He told this story about himself. He began earning $ 125 a week at the age of 23. That was a lot of money in those days. He got married and moved with his wife to a very wealthy neighborhood outside New York City. When he saw that rich people rode horses, Momand went horseback riding every day. When he saw that rich people had servants, Momand and his wife also hired a servant and gave big parties for their new neighbors.

    It was like a race, but one could never finish his race because one was always trying to keep up. The race ended for Momand and his wife when they could no longer pay for their new way of life. They moved back to an apartment in New York City.

    Momand looked around him and noticed that many people do things just to keep up with rich lifestyle of their neighbors. He saw the funny side of it and started to write a series of short stories. He called it “Keeping up with the Joneses” because “Jones” is a very common name in the United States. “Keeping up with the Joneses” came to mean keeping up with rich lifestyle of the people around you. Momand's series appeared in different newspapers across the country for over 28 years.

    People never seem to get tired of keeping up with the Joneses. And there are “Joneses” in every city of the world. But one must get tired of trying to keep up with the Joneses because no matter what one does, Mr. Jones always seems to be ahead.

    Why Do People Blink Their Eyes?

    People blink(眨眼) their eyes tens of thousands of times every day. Scientists have long believed blinking was an involuntary movement and served mainly to keep the eyeballs wet. But a new study suggests it has a more important purpose.

    An international team of scientists from the University of California at Berkeley studied the blinking of human eyelids. The journal Current Biology published their findings. The team said they found that blinking “repositions our eyeballs so we can stay focused” on what we are seeing. They said that when we blink our eyelids, the eyes roll back into their sockets--the bony area that surrounds and protects the eyes. However, the researchers found the eyes don't always return to the same position. They said this causes the brain to tell the eye muscles to reorganize our eyesight.

    Gerrit Maus is the lead writer of the report. He serves as an assistant professor of psychology at Nanyang Technological University in Singapore. Maus says: “Our eye muscles are quite sluggish(迟缓的) and imprecise, so the brain needs to constantly adapt its motor signals to make sure our eyes are pointing where they're supposed to. Our findings suggested that the brain measures the difference in what we see before and after a blink, and commands the eye muscles to make the needed corrections.” The researchers said that without such corrections our surroundings would appear unclear and even jumpy. They said the movement acts “like a Steadicam(摄影稳定器) of the mind.”

    The researchers said they asked volunteers to sit in a dark room while staring at a small dot on a flat surface. They used special cameras to follow the volunteer's blinks and eye movements. After each blink, the dot was moved one centimeter to the right. The volunteers did not notice this, but the brain did. It followed the movement and directed the eye muscles to refocus on the dot. After the dot was moved in this way 30 times, the volunteers' eyes changed their focus to the place where they predicted it would be.

    Professor Maus says “Even though participants did not consciously register that the dot had moved, their brains did, and adjusted with the corrective eye movement. These findings add to our understanding of how the brain constantly adapts to changes, commanding our eye muscles to correct for errors in our bodies' own hardware.”

    While the start of a new school year is always exciting, this year was even more so for some elementary school students in Auckland, New Zealand. They became the world's first kids to be “taught” by a digital teacher, Will. Will is just an avatar(用户头像) that appears on the student's desktop, tablet, or smartphone screen, not a human-like robot walking around the classroom.

    Auckland energy company Vector and AI company Soul Machines worked together to develop Will, which has been modeled after the human brain and nervous system, allowing it to perform human-like behavior. The digital teacher is currently assigned to teach Vector's “Be sustainable with energy,” a free program for Auckland elementary schools.

    Just like the humans it replaced, Will is able to instantly react to the students' responses to the topic. Thanks to a webcam(网络摄像头) and microphone, the avatar not only responds to questions the kids may have, but also picks up non-verbal cues(非口头提示). For instance, if a student smiles at Will, he responds by smiling back. This two-way interaction not only helps capture the students' attention, but also allows the program's developers to monitor their engagement, and make changes if needed.

    Vector's Chief Digital Officer, Nikhil Ravishankar says, “What was fascinating to me was the reaction of the children to Will. The way they look at the world is so creative and different, and Will really captured their attention.”

    Will, in place since August 2018, has been a great success thus far. However, regardless of how popular it becomes, Will is unlikely to replace human educators any time soon. For one, the avatar's knowledge base is severely restricted. But more importantly, even the smartest digital avatars could never predict and react to all the unexpected situations that educators have to deal with on a daily basis. However, it could come in handy as a “personal tutor”, providing kids with one-on-one help on specific subjects or even topics.