A Special Appointment

    Years ago I moved to Woodland Hills to take a job in a small hospital's emergency department. No one wanted to work on Christmas Eve, so the shift (轮班) went to me. I kissed my family goodbye and went off to spend the night in the hospital. It was a thankless job.

At 9 pm, the ambulance brought in a man in his 60s who was having a heart attack. His face was pale, and he was frightened. The whole night I did my best to save his life. Before I left in the morning to spend Christmas with my family, I stopped by to see how he was doing. It was still tough, but he had survived the night and was sleeping.

    The following year I got Christmas Eve duty again. At 9 pm sharp, the ward clerk told me there was a couple who wanted to speak with me. When I approached them, the man introduced himself as Mr. Lee and said, “You probably don't remember me, but last Christmas Eve you saved my life. Thank you for the year you gave me.” He and his wife hugged me, handed me a small gift, and left.

    The following year a new doctor had joined the group, but I wanted to see if Mr. and Mrs. Lee would return. This time, I volunteered for the shift. I kept an eye on the door. Once again, at exactly 9 pm, the Lees appeared, carrying a warmly wrapped bundle. It was their new grandchild. Mr.Lee, his family and I spent 13 Christmas Eves together. In the later years the staff all knew about the story and would work to give me time with him in the break room, where we spent a half-hour each Christmas Eve.

    The last year I saw him, he brought me a gift. I carefully opened the package and found a crystal (水晶) bell inside. It was engraved (镌刻) with a single word: Friendship. Now, my family, friends and I ring that bell every Christmas Eve at exactly 9 pm and offer our best wishes to the man who we won't forget.

     “Sugar, alcohol and tobacco,” economist Adam Smith once wrote, “are commodities which are nowhere necessaries of life, which have become objects of almost universal consumption, and which are, therefore, extremely popular subjects of taxation.”

    Two and a half centuries on, most countries impose (征税) sort of tax on alcohol and tobacco. With obesity levels putting increasing pressure on public health systems, governments around the world have begun to toy with the idea of taxing sugar as well.

    Whether such taxes work is a matter of debate. A preliminary review of Mexico's taxation found a fall in purchases of taxed drinks as well as a rise in sales of untaxed and healthier drinks. By contrast, a Danish tax on foods high in fats was abandoned a year after its introduction, during claims that consumers were avoiding it by crossing the border to Germany to satisfy their desire for cheaper, fattier foods.

    The food industry has, in general, been firmly opposed to such direct government action. Nonetheless, the renewed focus on waistlines means that industry groups are under pressure to demonstrate their products are healthy as well as tasty.

    Over the past three decades, the industry has made some efforts to improve the quality of its offerings. For example, some drink manufactures have cut the amount of sugar in their beverages (饮料).

    Many of the reductions over the past 30 years have been achieved either by reducing the amount of sugar, salt or fat in a product, or by finding an alternative ingredient. More recently, however, some companies have been investing money in a more ambitious undertaking: learning how to adjust the fundamental make-up of the food they sell. For example, having salt on the outside, but none on the inside, reduces the salt content without changing the taste.

    While reformulating (再制定) recipes is one way to improve public health, it should be part of a multisided (多边的) approach. The key is to remember that there is not just one solution. To deal with obesity, a mixture of approaches, which include reformulation, taxation and adjusting portion sizes, will be needed. There is no silver bullet.

    Some parents can't resist the strong desire to help their children play hooky (逃学) for a trip. Five-year-old Erica and her siblings Alex, 9, and Kate, 12, missed school in Denver on Aug. 21, 2017. Their father Mr. Reed took them on a camping trip to Halsey to see the solar eclipse (日食). Kate had told her teachers she'd be absent and Mr. Reed let Erica's and Alex's teachers know, too. But he didn't ask for permission.

    Mr. Reed has loved astronomy since seeing Neil Armstrong walk on the moon on his sixth birthday. He says, “I want my own kids to have a similar kind of wonderment and hope about future discoveries.”

    Parents often dream of traveling with their children to teach them about science, geography and culture. Many teachers support them, as the Reed children's teachers did. Other teachers were angry about the extra work.

    Teacher Amanda says she feels frustrated when parents take students out of school for family trips. If she sends homework, she finds it's often returned incomplete or incorrect, because the absent student didn't hear her explanation in class. Some students suffer anxiety as they struggle to catch up. Research shows that students who are absent often, for any reason—excused or unexcused—performed more poorly in school.

    Garrick agreed to miss five days of school for the Antarctic trip last year as a senior high school student, however. Managing the homework was a challenge, but it helped him gain time management skills. “And the trip is worth the effort,” he says, “sparking his interest in international relations. You can't really put a price on changing your world view,” Garrick says. “That's what travel has done for me. It has changed how I think about things.”

    Sue Hendrickson is a self-taught fossil（化石）hunter. As a kid, Sue Hendrickson often walked with her head down. “People said, 'Look up. Smile!” she says. “Now, I realize I was born to look for things and just didn't know it.”

    Sue Hendrickson does more than look—she finds valuable things: Shipwrecks（沉船）with treasure, ancient sunken cities, and in 1990, she found Sue, the world's largest, most complete Tyrannosaurus rex（霸王龙）. Is Hendrickson lucky? Well, maybe. But she also knows how to look.

    “I limit the area where I'm going to look,” she says. No one knew the location of the sunken ship San Diego in the Philippines. For a year, Hendrickson and other researchers searched papers and sailors' diaries. “The descriptions of the ship's sailors led us to the wreck,” she says. The team also used a tool that can respond to metal. This tool found the San Diego. All the work paid off. The 400-year-old ship was complete, with valuable gold and silver coins.

    To find the dinosaur she calls “the biggest animal that ever walked on earth,” Hendrickson started with maps made to search for oil. What Hendrickson found was the largest and most complete T-rex found to date. The T-rex is 42 feet long with 200 bones! Because it is so complete, scientists were able to infer that Sue walked at about 6 miles per hour and did not run faster than 15 miles an hour. Before Sue was discovered, they thought T-rex was much faster. To learn more about T-rex Sue, go to the Field Museum in Chicago.

    There's plenty left to be found, Hendrickson says, including answers to mysterious such as how T-rex lived. “I tell kids that they need to grow up and work them out because all of us old persons haven't yet!”

    Most dog owners are convinced that their four-legged friends know exactly what they mean when they use certain words like sit, stay or treat. However, researchers have always wondered whether dogs really understand human speech or if they rely on other information to get the meaning. For example, does the word “fetch” form a picture of a stick or ball in the dog's mind, or does the dog bring back the object based on the owner's voice or gesture? A new study by scientists at Atlanta's Emory University seems to indicate that “man's best friend” does indeed know what the owner is saying.

    The researchers began by asking the owners of twelve dogs of various kinds to train their pets to identify two toys of different materials, such as a toy animal and a ball. Once the dogs had mastered the task, they took turns inside a special scanner. The owners then tested their dog's language skill by first calling out the names of the toys they had been trained to recognize and then saying meaningless words such as “bobbu” and “bodmick” while holding up random objects the dogs hadn't seen before.

    The scans suggested that the parts of the dogs' brains responsible for processing of sounds showed different brain patterns when they heard words they were familiar with, compared with the ones they had never heard before. While that was not enough to prove that the dogs were picturing their toys when they heard the word, it did indicate some sort of recognition. The researchers believe this is an important step forward in understanding how dogs process language.

    Even more interesting was that the dog's brains showed a higher level of neural(神经)activity at the sound of unknown words. This is the exact opposite of what happens in human brains, which get more active at the sound of familiar words. The researchers say the dogs may become cheerful at the sound of new words to try to understand them in the hope of delighting their masters. “Dogs want to please their owners, and perhaps also receive praise or food,” says Empty neuroscientist Gregory Burns, senior author of the study.

    However, though your pet may understand human speech, the scientists recommend using visual signals and smell for training. “When people want to teach their dog a trick, they often use spoken command because that's what humans prefer, ”Prichard says.“ From the dog's view, however, a visual command might be more effective, helping the dog learn the trick faster.”

    Languages have been coming and going for thousands of years, but in recent times there has been less coming and a lot more going. When the world was still populated by hunter-gatherers, small, tightly knit(联系) groups developed their own patterns of speech, independent of each other. Some language experts believe that 10,000 years ago, when the world had just five to ten million people, they spoke perhaps 12,000 languages between them.

    Soon afterwards, many of those people started settling down to become farmers, and their languages too became more settled and fewer in number. In recent centuries, trade, industrialization, the development of the nation-state and the spread of universal compulsory education, especially globalization and better communications in the past few decades, all have caused many languages to disappear, and dominant languages such as English, Spanish and Chinese are increasingly taking over.

    At present, the world has about 6,800 languages. The distribution of these languages is hugely uneven. The general rule is that mild zones have fewer languages spoken by many people while hot, wet zones have more, often spoken by small numbers. Europe has only around 200 Languages: the Americas about 1,000, Africa 2,400; and Asia and the Pacific perhaps 3,200, of which New Guinea alone accounts for well over 800. The median number(中位数) of speakers is a mere 6,000, which means that half the world's languages are spoken by fewer people than that.

    Now over 400 of the total of 6,800 languages are close to extinction(消亡), with only a few elderly speakers left. None of these seems to have chances of survival.