People around the world are superstitious about numbers; even those ancient Greeks believed that all numbers and their multiples had some mystical significance.

    Those numbers between 1 and 13 were in particular to have a powerful influence over the affairs of men.

    For example, it is commonly said that luck, good or bad, comes in threes; if an accident happens, two more of the same kind may be expected soon afterwards. The arrival of a letter will be followed by two others within a certain period.

    Another belief involving the number three has it that it is unlucky to light three cigarettes from the one match. If this happens, the bad luck that goes with the deed falls upon the person whose cigarette was the last to be lit. The ill-men linked to the lighting of three things from one match or candle goes back to at least the 17th century and probably earlier. It was believed that three candles alight at the same time would be sure to bring bad luck; one, two, or four, were permissible, but never just three.

    Seven was another significant number, usually regarded as a bringer of good luck. The ancient astrologers believed that the universe was governed by seven planets; students of Shakespeare will recall that the life of man was divided into seven ages. Seven horseshoes nailed to a house will protect it from all evil.

    Nine is usually thought of as a lucky number because it is the product of three times three. It was much used by the Anglo Saxons in their charms for healing.

    Another belief was that great changes occurred every 7th and 9th of a man's life. Consequently, the age of 63 (the product of nine and seven) was thought to be a very perilous time for him. If he survived his 63rd year he might hope to live to a ripe old age.

    Thirteen, as we well know, is regarded with great awe and fear. The common belief is that this derives from the fact that there were 13 people at Christ's Last Supper. This being the eve of his betrayal, it is not difficult to understand the significance given to the number by the early Christians.

    In more modern times 13 is an especially unlucky number of a dinner party, for example. Hotels will avoid numbering a floor the 13th; the progression is from 12 to 14, and no room is given the number 13. Many home owners will use 12 1/2 instead of 13 as their house number.

    Yet oddly enough, to be born on the 13th of the month is not regarded with any fear at all, which just shows how irrational we are in our superstitious beliefs.

    What's more exciting than having a fresh hot pizza delivered to your door?  How about having it brought to you by a robot?  Thanks to Domino's Robotic Unit or DRU, that just became a reality! On March 8, the three-foot tall robot delivered its first pizza to some lucky residents in Brisbane, Australia.

    The fully autonomous DRU is the result of cooperation between Domino's Pizza Australia and Marathon Robotics. The 450-pound machine that travels at a maximum speed of 12. 4 miles an hour can traverse a distance of up to 12 miles and back, before requiring to recharge the battery. LIDAR, a laser-based sensor technology similar to the one used in self-driving cars, enables DRU to detect and avoid obstacles, while traditional sensors, much like those used in vacuum robots ensure its path is safe as it heads to its destination.

    The robot can fit up to ten pizzas and even has a separate cold area to accommodate drink orders. To access their food, customers have to enter the unique code provided for them by the company. This not only ensures that they pick up the right pizza, but also prevents the pies from getting stolen.

    Scientists expect additional DRU's to be ready for service in their various Queensland locations within the next six months. But don't expect these super cute robots to replace humans anytime soon. According to Domino's the DRU still needs extensive testing, which the company believes could take up to two years.

    And then there is also the issue of regulations. The public use of autonomous vehicles is still banned in most countries. But Don Meij, the CEO and Managing Director of Domino's Pizza Australia New Zealand Ltd, is not worried. He is“confident that one day DRU will become an integral part of the Domino's family. ”

    When I was younger, I thought that boys and grown men should not cry. The tears were signs of being weak and a sissy(胆小鬼), which a man is not supposed to be. This was even strengthened in my young mind when the song, Boys Don't Cry, came out in the early 1980s.

    But just this June, I discovered that courage is not all about trying to keep all the pain inside in check. Courage is not all about trying to hide the tears. It is the opposite — the tears strengthen the heart's courage. And I saw this in my father. That day my father cried.

    My 18-year-old sister eloped (私奔) and from it I saw how weak my father's heart was. My sister and I were used to seeing him as an iron-willed figure and authoritarian father.

    For three days after my sister eloped, he would not talk. He would just sit quietly outside our house in the dark. On the fourth night, I sat beside him and asked him to tell me what he felt about everything.

    It has been years since I have laid my hand on my father's shoulder as we have drifted apart (疏远) farther and farther while I was growing up. That night，though, I sensed my father trying to control his pain and I wanted him to be able to let it out. We have all cried over what happened except him. All of us except him.

    The simple touch and my words, "Dad, it is not your fault.", broke my father's dam.

    In the darkness, he began to cry. I felt his shoulders shaking as he whispered, "Where did

    I go wrong? All I ever wanted was for my children to grow up right. Why couldn't your sister wait?"

    I understood then why he preferred to be in the dark. By being there, he hoped to spare his family of a father's pain. His tears, though we did not see them before that night, were there all the same. I saw his courage, that night when my father cried with my hand on his shoulder, and understood his pain.

    The haunting paintings of Helene Schjerfbeck, on show in the final leg of a travelling tour that has already attracted thousands of visitors in Hamburg and the Hague, may come as a surprise to many. Few outside the Nordic(北欧的) world would recognize the works of this Finnish artist who died in 1946. More people should. The 120 works have at their core 20 self-portraits, half the number she painted in all. The first, dated 1880, is of a wide-eyed teenager eager to absorb everything. The last is a sighting of the artist's ghost-to-be.

    Prematurely gifted, Schjerfbeck was 11 when she entered the Finnish Art Society's drawing school. “The Wounded Warrior in the Snow”, a history painting, was bought by a private collector and won her a state travel grant when she was 17. Schjerfbeck studied in Paris, went on to Pont-Aven, Brittany, where she painted for a year, then to Tuscany, Cornwall and St Petersburg. During her 1887 visit to St Ives, Cornwall, Schjerfbeck painted “The Convalescent”. A child wrapped in a blanket sits supported up in a large wicker(柳条编制的) chair, toying with a sprig(小枝条). The picture won a bronze medal at the 1889 Paris World Fair and was bought by the Finnish Art Society. To a modern eye it seems almost sentimental(感伤的) and is made up for only by the somewhat astonished, sad expression on the child's face, which may have been inspired by Schjerfbeck's early experiences. At four, she fell down a flight of steps and never fully recovered.

    In 1890, Schjerfbeck settled in Finland. Teaching exhausted her, she did not like the works of other local painters, and she was further isolated when she took on the care of her mother. “If I allow myself the freedom to live an isolated life”, she wrote, “then it is because it has to be that way.” In 1902, Schjerfbeck and her mother settled in the small, industrial town of Hyvinkaa, 50 kilometres north of Helsinki. Isolation had one desired effect for it was there that Schjerfbeck became a modern painter. She produced still lives and landscapes but above all moody yet sharp portraits of her mother, local school girls, women workers in town.

    “I have always searched for the dense depths of the soul, which have not yet been discovered by humans themselves”, she wrote, “where everything is still unconscious -- there one can make the greatest discoveries.” She experimented with different kinds of underpainting, scraped and rubbed, made bright rosy red spots; doing whatever had to be done to capture the subconscious — her own and that of her models. In 1913, Schjerfbeck was rediscovered by an art dealer and journalist, Gosta Stenman. Once again she was a success.

    It is common to see many different kinds of insects while spending time outside in the summer. Some of them do not trouble people and can even add beauty to the natural environment. Other insects can harm the environment or humans. The population of these insects seems to stay large and healthy.

    But scientists say this does not appear to be true for some flying insects that serve an important purpose. There is growing evidence that these insects are decreasing across the world.

    One researcher looking into the present insect population is Doug Tallamy, a professor at the University of Delaware. He remembers walking through Washington D. C., in the past when it was "alive with insects, especially butterflies". Now, he said, "The flying insects are actually gone." Wilson said this point seemed to be proved during a drive he made last year from Boston to Vermont. He was surprised that, during his trip, he counted only one insect that had hit the car's front window. Several other scientists have carried out similar tests by checking how many insects hit their cars while traveling.

    While researchers admit this method is not scientific, they say it can still help them understand the changing flying insect population. There have not been many studies done on the flying insect populations covering large areas. However, some international research suggests a downward turn. In 2006, a group of studies showed that there had been a 14-percent drop in ladybugs(瓢虫) in the United States and Canada from 1987 to 2006. In Germany, a 2017 study found an 82-percent drop in the number of flying insects compared to levels recorded in 1990.

    After the German study, other countries also started looking into the problem. David Wagner of the University of Connecticut says other evidence leads him to believe the findings of the 2017 study are "clearly not a German thing".

    Scientists in New Zealand have found fossilized (化石的) leg bones from a penguin believed to have been about the size of an adult human. The previously undiscovered giant penguin species likely stood about 1.6 meters tall and weighed up to 80 kilograms.

    The penguin existed about 60 million years ago. The bones are believed to be from the oldest of several species of giant penguins that lived after dinosaurs died out. A fossil hunter found the bones last year in the Waipara River bed near the city of Christchurch. The bones are from the animal's legs and feet. Scientists confirmed that the bones came from a newly discovered species.

    Paul Scofield is senior curator (馆长) at New Zealand's Canterbury Museum. He co-wrote a paper on the discovery. He said that the bones are an important find. They show that the species is similar to another giant penguin found in Antarctica in 2000. The latest discovery, he said, helps show a clear connection between the two areas during the Paleocene period. This period lasted from 66 million to 56 million years ago.

    Scofield said the penguins were able to grow larger after entering a new development period following the extinction of dinosaurs, sea reptiles and huge fish. Scofield added that the giant penguins became extinct within 30 million years, as large mammals began to rule the waters.

    John Cockrem is a penguin expert at the country's Massey University who was also not involved in the research. He said the discovery helps add to what we know about giant penguins. He said it also confirmed New Zealand as the penguin center of the world.

    New Zealand is believed to have been home to many giant bird species that later disappeared. These included the world's largest parrot, a giant eagle and an emu-like bird called the moa. Recently, Canterbury Museum announced the discovery of an unusually large parrot believed to have lived about 19 million years ago. Scientists say the bird stood about one meter tall.