I tried not to be biased, but I had my doubts about hiring Stevie. His social worker assured me that he would be a good, reliable busboy. But I had never had a mentally handicapped employee. He was short, a little fat, with the smooth facial features and thick-togued speech of Down's Syndrome（唐氏综合症）. I thought most of my customers would be uncomfortable around Stevie, so I closely watched him for the first few weeks.

    I shouldn't have worried. After the first week, Stevie had my staff wrapped around his stubby little finger, and within a month my regular trucker customers had adopted him as their official truck stop mascot. After that, I really didn't care what the rest of the customers thought of him. He was like a 21-year-old in blue jeans and Nikes, eager to laugh and eager to please, but fierce in his attention to his duties. Every salt and pepper shaker was exactly in its place, not a bread crumb or coffee spill was visible when Stevie got done with the table. Our only problem was persuading him to wait to clean a table until after the customers were finished.

    Over time, we learned that he lived with his mother, a widow who was disabled. Money was tight, and what I paid him was probably the difference between them being able to live together and Stevie being sent to a group home.

    That's why the restaurant was a gloomy place that morning last August, the first morning in three years that Stevie missed work. He was at the Mayo Clinic in Rochester getting a heart surgery. His social worker said that people with Downs Syndrome often had heart problems at an early age and there was a good chance he would come through the surgery in good shape and be back at work in a few months.

    A ripple of excitement ran through the staff later that morning when word came that he was out of surgery, in recovery, and doing fine. Frannie, my head waitress, did a little dance when she heard the good news. Belle Ringer, one of our regular trucker customers, stared at her and asked, “Okay, Frannie, what was that all about?”

    "We just got word that Stevie is out of surgery and going to be okay."

    "I was wondering where he was. I had a new joke to tell him. What was the surgery about?"

    Frannie quickly told Belle Ringer and the other two drivers sitting at his booth about Stevie's surgery, then sighed: "Yeah, I"m glad he is going to be OK," she said. "But I don't know how he and his Mom are going to handle all the bills. From what I hear, they"re barely getting by as it is."

    Belle Ringer nodded thoughtfully, and Frannie hurried off to wait on the rest of her tables.

    After the morning rush, Frannie walked into my office. She had a couple of paper napkins in her hand.

    "What's up?" I asked.

    "I cleared off that table where Belle Ringer and his friends were sitting after they left, and I found this. This was folded and tucked under a coffee cup."

    She handed the napkin to me, and three $20 bills fell onto my desk when I opened it. On the outside, in big, bold letters, was printed "something For Stevie".

    That was three months ago. Today is New Year's day, the first day Stevie is supposed to be back to work. His placement worker said he had been counting the days until the doctor said he could work, I arranged to have his mother bring him to work, met them in the parking lot and invited them both to celebrate his day back. I took him and his mother by their arms. "To celebrate you coming back, breakfast for you and your mother is on me.”

    I led them toward a large corner booth. I could feel and hear truck customers and the rest of the staff following behind as we marched through the dining room. We stopped in front of the big table. Its surface was covered with coffee cups and dinner plates, all sitting slightly on dozens of folded paper napkins.

    "First thing you have to do, Stevie, is clean up this mess," I said.

    Stevie looked at me, and then pulled out one of the napkins. It had 'something for Stevie" printed on the outside. As he picked it up, two $10 bills fell onto the table. Stevie stared at the money, then at all the napkins peeking from beneath the tableware, each with his name printed on it.

    I turned to his mother. "There's more than $10,000 in cash and checks on that table, all from truckers and trucking companies that heard about your problems. Happy Thanksgiving!"

    While everybody else was busy shaking hands and hugging each other, Stevie, with a big, big smile on his face, was busy clearing all the cups and dishes from the table.

    The arts, especially music, should be part of every school's lessons at every grade level. Students would be much smarter if they had musical experience. They could improve their classroom skills, like paying attention and following directions. People develop all these skills when they learn music. Making music also lets children use their imagination. It provides students with a chance to try out their own ideas.

    Music not only makes children better students, but also gives them something positive to do. In a music program, children can be part of a band instead of joining a gang(团伙). Parents can enjoy listening to their children's music instead of seeing them glued to a computer or TV screen. In a school band, students get to be part of a team. They can get along well with old friends and make new friends through music.

    Music builds self-confidence, too. It gives children a sense of achievement and success. Making music is something for them to be proud of. And it lets kids practice performing in front of an audience. Music gives children an opportunity for self-expression, and that helps develop their self-confidence.

    Once again, music is important because it can make children better students, give them something positive to do, and build their character. That is why music should be offered in every single grade in every school.

    As global temperatures rise, trees around the world are experiencing longer growing seasons, sometimes as much as three extra weeks a year. All that time helps trees grow faster. For the past 100 years, trees have been experiencing fast growth in temperate regions from Maryland to Finland, to Central Europe, where the growth rate of some trees has even sped up nearly 77% since 1870. Assuming wood is just as strong today, those gains would mean more timber(木材) for building, burning, and storing carbon captured from the atmosphere. But is wood really as dense as it used to be?

    Hans Pretzsch, a forest scientist at the Technical University of Munich in Germany, and his colleagues wanted to find an answer. They carried out a study of the forests of Central Europe. They started with 41 experimental plots in southern Germany, some of which have been continuously monitored since 1870. Pretzsch and his team took core samples from the trees—which included Norway spruce, sessile oak, European beech, and Scots pine—and analyzed the tree rings using a high-frequency probe.

    They found that in all four species, wood density has decreased by 8% to 12%, they report online in Forest Ecology and Management. “We expected a trend of the wood density like this, but not such a strong and significant decrease,” Pretzsch says. Increasing temperatures, and the faster growth they spur, probably account for some of the drop. Another factor, Pretzsch says, is more nitrogen in the soil from agricultural fertilizer(化肥) and vehicle exhaust. Previous studies have linked increased fertilizer use to decreased wood density. Above all, the study suggests that the higher temperatures—combined with pollution from auto exhaust and farms—are making wood weaker, resulting in trees that break more easily and wood that is less durable.

    “I am getting worried,” says Richard Houghton, an ecologist at the Woods Hole Research Center in Falmouth, Massachusetts, who was not part of the new study. As the density of the samples dropped, so did their carbon content, by about 50%. That means forests may suffer more damage from storms and may be less efficient at soaking up the greenhouse gas carbon dioxide (CO2) than scientists had thought, Houghton says.

    For all the technological wonders of modem medicine, health care-with its fax machines and clipboards (写字板) —is out of date. This outdated era is slowly drawing to a close as the industry catches up with the artificial-intelligence (AI) revolution.

    Eric Topol, an expert in heart disease and enthusiast for digital medicine, thinks AI will be particularly useful for such tasks as examining images, observing heart traces for abnormalities or turning doctors' words into patient records. It will be able to use masses of data to work out the best treatments, and improve workflows in hospitals. In short, AI is set to save time, lives and money.

    The fear some people have is that AI will be used to deepen the assembly-line culture of modem medicine. If it gives a "gift of time" to doctors, they argue that this bonus should be used to extend consultations, rather than simply speeding through them more efficiently.

    That is a fine idea, but as health swallows an ever-bigger share of national wealth, greater efficiency is exactly what is needed, at least so far as governments and insurers are concerned. Otherwise, rich societies may fail to cope with the needs of ageing and growing populations. An extra five minutes spent chatting with a patient is costly as well as valuable. The AI revolution will also enable managerial accountants to adjust and evaluate every aspect of treatment. The autonomy of the doctor will surely be weakened, especially, perhaps, in public-health systems which are duty-bound to cut unnecessary costs.

    The Hippocratic Oath (誓言) holds that there is an art to medicine as well as a science and that "warmth, sympathy and understanding may outweigh the surgeon's knife or the chemist's drug". There's lots of sense in it: the patients of sympathetic physicians have been shown to recover better. Yet as the supply of human carers fails to satisfy the demand for health care, the future may involve consultations on smartphones and measurements monitored by chatbots. The considerately warmed stethoscope (听诊器), placed gently on a patient's back, may become a relic of the past.

     Aspirin has long been praised as a wonder drug. An aspirin a day keeps the doctor away. Many Americans have been taking one aspirin a day, believing it would protect them from a heart attack a stroke(中风), and even a cancer. But several recent studies have thrown this into question. Daily use of aspirin can have serious side effects(副作用).

    One study followed more than 19,000 healthy people aged 65 and older. They were required to take either 100 mg of aspirin (a little more than the 81 mg dose that most people take) or a placebo(无效对照剂) every day for about years, Not only did people in the aspirin group not lower their risk of heart disease, or disability but they were also more likely to suffer from bleeding into the brain or stomach. And they were more likely to die because of an increased risk of giving in to cancer, Similarly, an experiment of more than 12. 500 people aged 55 and older who have a cardiovascular (心血管的)risk found no benefit to taking aspirin daily. In study of more than 15,000 people with diabetes(糖尿病), a daily aspirin did prevent heart attacks and strokes, but it also caused serious bleeding.

    Although some earlier research has proved that aspirin can help people who have already had or are at high risk for heart attacks or strokes, the drug's value is not so clear for people, especially older people,

    The bottom line is this: Be smart and be safe. You should not take daily low-dose aspirin without talking to a doctor if you.

    ● Are over the age of 70

    ● Drink wine regularly

    ●Are on any simple medical operations

    A study published in the journal Science reveals that since 1970, bird populations in the United States and Canada have declined by 29 percent, or almost 3 billion birds. The results show tremendous losses across diverse groups of birds and habitats - from iconic songsters such as meadowlarks to long-distance migrants such as swallows.

    "These data are consistent with what we're seeing elsewhere," said coauthor Peter Marra, former head of the Smithsonian Migratory Bird Center. It's urgent to address ongoing threats, both because the domino effects (多米诺效应)can lead to the decay of ecosystems that humans depend on for our own health and livelihoods and because people all over the world cherish birds in their own right. Can you imagine a world without birdsong?"

    Evidence for the declines emerged from detection of migratory birds in the air from 143 NEXRAD weather radar stations across the continent in a period spanning over 10 years as well as from nearly 50 years of data collected through multiple monitoring efforts on the ground. Citizen-science participants also contributed a lot, for the analysis included citizen-science data from the North American Breeding Bird Survey coordinated by the Canadian Wildlife Service- the main sources of long-term, large-scale population data for North American birds.

    The study noted that the largest factor driving these declines is likely the widespread loss and degradation of habitat, especially due to agricultural intensification and urbanization. Other studies have documented death from predation (捕食)by domestic cats; collisions with glass, buildings, and other structures; and pervasive (普遍的)use of pesticides associated with widespread declines in insects, an essential food source for birds. Climate change is expected to compound these challenges by altering habitats and threatening plant communities that birds need to survive.

    "It's a wake-up call that we've lost more than a quarter of our birds in the U.S. and Canada," said coauthor Adam Smith from Environment and Climate Change Canada. But the crisis reaches far beyond our individual borders. Many of the birds that breed in Canadian backyards migrate through or spend the winter in the U.S. and places farther south - from Mexico and the Caribbean to Central and South America. What our birds need now is an historic, hemispheric effort that unites people and organizations with one common goal: bringing our birds back.