We discuss the issue of when to help a patient die. Doctors of our generation are not newcomers to this question. Going back to my internship（实习）days, I can remember many patients in pain, sometimes in coma(昏迷), with late, hopeless cancer. For many of them, we wrote an order for heavy medication—morphine(吗啡)by the clock. This was not talked about openly and little was written about it. It was essential, not controversial.

The best way to bring the problem into focus is to describe two patients whom I cared for. The first, formerly a nurse, had an automobile accident. A few days later her lungs seemed to fill up; her heart developed dangerous rhythm disturbances. So there she was: in coma, on a breathing machine, her heartbeat maintained with an electrical device. One day after rounds, my secretary said the husband and son of the patient wanted to see me. They told me their wife and mother was obviously going to die; she was a nurse and had told her family that she never wanted this kind of terrible death, being maintained by machines. I told them that while I respected their view, there was nothing deadly about her situation. The kidney(肾) failure she had was just the kind for which the artificial kidney was most effective. While possibly a bit reassured, they were disappointed. Here was the head surgeon seemingly determined to keep everybody alive, no matter what.

Within a few days the patient's pacemaker(起搏器) could be removed and she awoke from her coma. About six months later, the door of my office opened and in walked a gloriously fit woman. After some cheery words of appreciation, the father and son asked to speak to me alone. As soon as the door closed, both men became quite tearful. All that came out was, "We want you to know how wrong we were."

The second patient was an 85-year-old lady whose hair caught fire while she was smoking. She arrived with a deep burn; I knew it would surely be deadly. As a remarkable coincidence there was a meeting for discussion going on at the time in medical ethics(道德). The speaker asked me if I had any sort of ethical problem I could bring up for discussion. I described the case and asked the students their opinion. After the discussion, I made a remark that was, when looking back, a serious mistake. I said, "I'll take the word back to the nurses about her and we will talk about it some more before we decide." The instructor and the students were shocked: "You mean this is a real patient?" The teacher of ethics was not accustomed to being challenged by actuality. In any event, I went back and met with the nurses. A day or two later, when she was making no progress and was suffering terribly, we began to back off treatment. Soon she died quietly and not in pain. As a reasonable physician, you had better move ahead and do what you would want done for you. And don't discuss it with the world first. There is a lesson here for everybody. Assisting people to leave this life requires strong judgment and long experience to avoid its misuse.

    Music for Humans and Humpback Whales (座头鲸)

    As researchers conclude in Science, the love of music is not only a universal feature of the human species but is also deeply fixed in complex structures of the human brain and is far more ancient than previously suspected.

    In the articles, researchers present various evidence to show that music-making is at once an original human “business”, and an art form with skillful performers throughout the animal kingdom.

    The new reports stress that humans hold no copyright on sound wisdom, and that a number of nonhuman animals produce what can rightly be called music, rather than random sound. Recent in-depth analyses of the songs sung by humpback whales show that, even when their organ would allow them to do otherwise, the animals converge on the same choices related to sounds and beauty, and accept the same laws of song composition as those preferred by human musicians, and human ears, everywhere.

    For example, male humpback whales, who spend six months of each year doing little else but singing, use rhythms (节奏) similar to those found in human music and musical phrases of similar length—a few seconds. Whales are able to make sounds over a range of at least seven octaves (八度音阶), yet they tend to move on through a song in beautiful musical intervals (间隔), rather than moving forwards madly. They mix the sounds like drums and pure tones in a ratio (比例) which agrees with that heard in much western music. They also use a favorite technique of human singers, the so-called A-B-A form, in which a theme is stated, then developed, and then returned to in slightly revised form.

Perhaps most impressive, humpback songs contain tunes that rhyme. “This suggests that whales use rhyme, the same way we do: as a technique in poem to help them remember complex materials,” the researchers write.

    There are a lot of reasons why people calling 911 might not be able to tell operators which floor they're on in a high-rise building. They could be injured or simply confused. Yet precious minutes are wasted when emergency personnel have to search a building to find a person in need. With a new app called Sensory, emergency responders soon may be able to use a caller's smartphone to locate his exact position in a building.

    Columbia University researchers William Falcon and Henning Schulzrinne created Sensory using a two-step process. First, they used all existing smartphone features that help narrow down a caller's location. All iPhones produced after 2014 already include GPS and altimeter（测高仪） that can help emergency responders determine if a person is outdoors or inside a building. But when it comes to tall buildings, just knowing a person's altitude may not be enough，because the distance between floors changes from one building to another.

    So Falcon and Schulzrinne analysed the plans of figuring out the average distance between floors in residential（住宅的）buildings and office buildings among more than 1000 buildings in New York City. They tested their app in 63 experiments in five high-rise buildings and found that it could find a caller's location within two floors with about a 91 percent accuracy.

    In a survey conducted by Find Me 911 this year, dispatchers（调度员）said that they regularly received calls from people in need who often couldn't share their location. They sometimes accidentally give the wrong address or floor number. Some callers are too young to know their address. Dispatchers also received calls from those who are deaf or have hearing problems and they often couldn't hear the operator's questions.

    The new Sensory app could help shave precious minutes off the time it takes first responders to get to those calling for help. And it could make the difference between life and death.

    Nowadays six Amazon Scout delivery robots rolled out in a pilot program in Snohomish County, Wash. The robots carry meals, groceries and packages to homes and offices in this region just north of Seattle. They have appeared on the sidewalks of London, Beijing and other cities and communities worldwide. These machines must overcome pedestrian legs, naughty dogs and broken pavement, which raises some questions.

    These services are gaining attraction as a growing number of city residents expect immediate or scheduled delivery for just about everything. Between 2017 and 2018 online retail sales in the U.S. increased by 16 percent. On the final step of all these deliveries, called the last mile, humans on bicycles, motorized scooters (电动车) or large delivery trucks typically deliver packages. All the vehicles compete for space on busy urban streets. "Deliveries are trending upwards in all crowded city centers, and if city and state leaders don't start thinking about creative solutions like robot deliveries, we can expect even worse traffic jams," says Paul Mackie, director of a transportation policy research center in Arlington.

    A study by this center found 73 percent of delivery vehicles in Arlington were parked outside of authorized areas, often blocking bike lanes and crosswalks. By moving the last step of deliveries from the road to the sidewalk, cities could reduce traffic jams and solve the parking problem entirely, Mackie says.

    Companies such as Amazon are not developing this delivery technology simply to clear up urban traffic. Self-driving vehicles and sidewalk robots could cut down last-mile delivery costs in cities by as much as 40 percent, according to a 2018 report by a consultancy firm. A delivery robot can cost thousands of dollars to manufacture, and most currently require human management and conservation. But in the long run companies that use autonomous delivery vehicles in the next several years could end up saving billions of dollars, the report stated.

    Susan couldn't help it. She and her friends began lunch with cheese. Then they ate cheeseburgers and drank milk. Things seemed fine, but then suddenly Susan's stomach started making noise. Her stomach hurt, and, racing to the restroom, she had terrible gas! She was so ashamed. She had been so excited to go to lunch with her friends that she totally forgot to watch how many dairy products (奶制品) she ate! Susan is lactose intolerant (乳糖不耐受的), and eating too many dairy foods can make her feel really sick.

    Lactose intolerance means that the body can't easily digest (消化) a special sugar called lactose. Unfortunately for Susan and millions of other people with this problem, lactose is found in almost all dairy products — cheese, milk and ice cream.

    Our body uses lactase (乳糖酵素) to break lactose into a simpler form of sugar. Once lactose is broken down, it's easy to digest and it provides great energy for the body. But people like Susan don't have enough lactase to break down all the lactose they take in. So, about half an hour to two hours after eating dairy­rich foods, their stomachs begin to hurt and they have gas, making their stomachs get bigger. Sometimes they even get diarrhea (腹泻) when they eat too many dairy foods.

    So how can someone living with this problem still eat out with his or her friends? Here are some tips. If you're going to eat a dairy­rich food like ice cream, eat something that doesn't have any dairy with it, like a salad or a sandwich without cheese. This will help slow digestion, and your body will have time to create more lactase.

    University of Pennsylvania researchers say that for the first time they have linked social media use to increases in depression and loneliness. The idea that social media is anything but social when it comes to mental health has been talked about for years, but not many studies have managed to actually link the two. To do that, Penn researchers, led by psychologist Melissa Hunt, designed a study that focused on WeChat, Snapchat and Instagram.

    The study was conducted with 143 participants, who before they began, completed a mood survey and sent along photos of their battery screens, showing how often they were using their phones to access social media. "We set out to do a much more complete study which attempts to imitate real life." Hunt said.

    The study divided the participants into two groups： The first group was allowed to maintain their normal social media habits. The other, the control group, was restricted to 10 minutes per day on social media. The restrictions were put in place for three weeks and then the participants returned and were tested for outcomes such as fear of missing out, anxiety, depression and loneliness.

    The results showed a very clear link between social media use and increased levels of depression and loneliness. "Using less social media than you normally do would lead to significant decreases in both depression and loneliness," Hunt said.

    Social media invites what Hunt calls "downward social comparison." "When you're online, it can sometimes seem that everyone else is cooler and having more fun and included in more things and you're left out," Hunt said. And that's just generally discouraging. "Every minute you spend online is a minute you are not doing your work or not meeting a friend for dinner or having a deep conversation with your roommate." And these real life activities are the ones that can encourage self﹣esteem and self﹣worth, Hunt added.

    "People are on their devices, and that's not going to change," she said. But as in life, a bit of control goes a long way.