YOUR mom might cook a bowl of noodles for you on your birthday. But in the US, a mom makes a cupcake for her children on their birthday.

    Cupcakes are small, round cakes topped with frosting (糖霜). It has been an American tradition that moms bring cupcakes to the classroom to celebrate their child's birthday. But recently some doctors have called for this to be banned. They believe cupcakes contribute to child obesity. Despite their good intentions, however, some people believe that experts are interfering (妨碍) with American culture. The cupcake is seen as American as apple pie — only prettier.

    According to Marion Nestle, a professor of nutrition at New York University, the cupcake is the most democratic (民主的) of desserts. As they are small enough for one person, you don't have to share your cupcake with anyone — it's all yours. They are also all of the same size, so there can't be any cries of  “she got the bigger piece!”

    Each bite can taste different depending on how much icing you have. It is a lesson in self-determination. Some people eat only a little of the frosting every time, others have it all in just one bite.

    In recent years, eating a cupcake has become as trendy as having a cup of Starbucks coffee.

    Democratic presidential candidate Hillary Clinton jokingly promised on a talk show that if she was elected president, she would give everyone a cupcake on her birthday. Ruth Reichl, editor-in-chief of Gourmet magazine, explains that the rise of the cupcake is very much about going back to American national identity in food, which is all about comfort. “People want to think about when they and their country were innocent,” she said.

    However wealthy we may be, we can never find enough hours in the day to do everything we want. Economics deals with this problem through the concept of opportunity cost, which simply refers to whether someone's time or money could be better spent on something else.

    Every hour of our time has a value. For every hour we work at one job we could quite easily be doing another, or be sleeping or watching a film. Each of these options has a different opportunity cost—namely, what they cost us in missed opportunities.

    Say you intend to watch a football match but the tickets are expensive and it will take you a couple of hours to get to and from the stadium. Why not, you might reason, watch the game from home and use the leftover money and time to have dinner with friends? This—the alternative use of your cash and time—is the opportunity cost.

    For economists, every decision is made by knowledge of what one must forgo—in terms of money and enjoyment—in order to take it up. By knowing precisely what you are receiving and what you are missing out on, you ought to be able to make better-informed, more reasonable decisions. Consider that most famous economic rule of all: there's no such thing as a free lunch. Even if someone offers to take you out to lunch for free, the time you will spend in the restaurant still costs you something in terms of forgone opportunities.

    Some people find the idea of opportunity cost extremely discouraging: imagine spending your entire life calculating whether your time would be better spent elsewhere doing something more profitable or enjoyable. Yet, in a sense it's human nature to do precisely that—we assess the advantages and disadvantages of decisions all the time.

    In the business world, a popular phrase is “value for money.” People want their cash to go as far as possible. However, another is fast obtaining an advantage: “value for time.” The biggest restriction on our resources is the number of hours we can devote to something, so we look to maximize the return we get on our investment of time. By reading this passage you are giving over a bit of your time which could be spent doing other activities, such as sleeping and eating. In return, however, this passage will help you to think like an economist, closely considering the opportunity cost of each of your decisions.

    When I recently revealed to my friends, colleagues, and family members that I would be moving my family to Israel, the reactions were numerous and varied. Some people said it was an expected thing while others asked: Why now? What will you do?

    For me, making the move to Israel is the fulfillment of a dream that has lasted for my 47 years of life. I have always known that Israel is my home. Over the years Israel has been in my heart, but I have found a number of reasons to put off making it my permanent residence: kids, the economy, education… you name an excuse, and at some point I have probably used it.

    Truthfully, I believe that I was always just a little bit scared. And of course I still am, with the fear factor that is reported by the press surrounding the Israeli military and economy. However, it has come to the point when I have realized that for over 2000 years we have longed for this land, and that for 47 years I have denied the opportunity to make it my home. I am finally ready to fully grasp this opportunity.

    Over the years, I have always loved visiting Israel. I have traveled there with my family, and enjoyed introducing thousands of travelers to the country. I have come to love all of these things about Israel as a tourist because I get to love my home. And as far as waiting for the “perfect” condition under which to make aliyah, I believe the time is now!

    I have been asked many times if I am nervous about moving to Israel. Before I answer, I remember that we have overcome the Greeks, the Romans, the Russian killings, Hitler and the Holocaust(大屠杀)，and the armies of seven countries.

    How can I not feel confident that I , and my family, will overcome any difficulties that may come our way? I am not worrying, complaining, crying, or fearing as I prepare to make aliyah. I am proud and excited to say that I am fulfilling a 47-year-old dream: I am going home.

    Mayor Day called me that morning, his voice full of an urgency I'd never heard before. "These Chinese big people are coming to our town and I need you to prepare something really special for them. I'm relying on you, Adrian. The whole town is. This could be just the thing to put us over the top."

    "Okay, I'm on it," I said. I'm a caterer (酒席承办人), and for years I've done all the mayor's events for Thomasville, Alabama, our little town of 4,099. He likes everything I make, but I knew exactly what he wanted this time, banana pudding, his favorite.

    It's my mama's recipe. It was her desserts that she was known for. Mama cooked her banana pudding on the stove. Hers was thick and cream-colored, not dark yellow like the other ladies made. I remember practicing in the kitchen when I was a young girl. Mama showed me how to make banana pudding properly. "Good job, Adrian," Mama would say. I was so proud when I finally got mine just right, the way she did.

    For months Mayor Day had tried his best to persuade some Chinese businessmen who ran a copper company to build their new plant in Thomasville, but our little town didn't have the land they needed. "We are leaning toward Houston or Lamar," the company representative told Mayor Day. "There is nothing personal, just business."

    "Wait! What about Wilcox County?" the mayor asked. Wilcox, just east of us, was one of the poorest counties in the entire United States and had got plenty of land. There hadn't been any kind of plant built there since the 1970s.

    "But that's not your county," the company representative said. "Why are you lobbying (游说) for them?"

    "Because if you build in Wilcox County their economy will grow and so will Thomasville's. Besides, there's something to be said for loving your neighbor, isn't there?"

    The representative agreed to visit Wilcox County before the final decision was made. All the top leaders would come and have lunch in Thomasville, lunch that I cooked. And for dessert, the dish the mayor hoped would sweeten the deal. Banana pudding with 300 jobs riding on it, I knew it had to be perfect, like Mama's.

    The luncheon was held at the Thomasville Civic Center. Next to each plate I'd placed a little cup of pudding. I looked on anxiously as the Chinese businessmen eyed the dessert. Were they curious or sickening? One of the men pointed at his cup and said something to the translator. I couldn't hear his answer but the businessman still looked puzzled. He took a spoon, inserted it into the pudding, then put barely a taste to his lips. For a moment there was no reaction. Then he smiled, a grin that went from ear to ear. The rest of the businessmen started eating their pudding, one bite after another. In seconds all the cups were empty.

    One of the businessmen looked toward me and said something to the translator, who waved me over to the table. "Excuse me," he said. "Is there more? More …" he searched for the word, "… pie?" I brought out all the banana pudding. Even last cup was finished. By the time the men put down their dessert spoons they'd reached an agreement. They needed to know more about Wilcox County. There would be another meeting, another lunch.

    "And we will have again the banana pie?" one of the leaders asked.

    Mayor Day didn't miss a beat. "Absolutely," he said. "Adrian's lunches always come with banana pie."

    And a few months later, when it was announced that the plant would be built in Wilcox County instead of Houston, everyone joked that the decision had come down to one thing. Mama's been away for a few years now, but I like to think she's up in heaven, looking down on that new copper plant going up in Wilcox County, and saying, "Good job, Adrian."

Plastic-Eating Worms

    Humans produce more than 300 million tons of plastic every year. Almost half of that winds up in landfills(垃圾填埋场)，and up to 12 million tons pollute the oceans. So far there is no effective way to get rid of it, but a new study suggests an answer may lie in the stomachs of some hungry worms.

    Researchers in Spain and England recently found that the worms of the greater wax moth can break down polyethylene, which accounts for 40% of plastics. The team left 100 wax worms on a commercial polyethylene shopping bag for 12 hours, and the worms consumed and broke down about 92 milligrams, or almost 3% of it. To confirm that the worms' chewing alone was not responsible for the polyethylene breakdown, the researchers made some worms into paste(糊状物) and applied it to plastic films. 14 hours later the films had lost 13% of their mass--apparently broken down by enzymes(酶)from the worms' stomachs. Their findings were published in Current Biology in 2017.

    Federica Bertocchini, co-author of the study, says the worms' ability to break down their everyday food-beeswax--also allows them to break down plastic "Wax is a complex mixture, but the basic bond in polyethylene, the carbon-carbon bond, is there as well, "she explains. "The wax worm evolved a method or system to break this bond. "

    Jennifer Debruyn, a microbiologist at the University of Tennessee, who was not involved in the study, says it is not surprising that such worms can break down polyethylene. But compared with previous studies, she finds the speed of breaking down in this one exciting. The next step, DeBruyn says, will be to identify the cause of the breakdown. Is it an enzyme produced by the worm itself or by its gut microbes(肠道微生物)?

    Bertocchini agrees and hopes her team's findings might one day help employ the enzyme to break down plastics in landfills. But she expects using the chemical in some kind of industrial process-not simply "millions of worms thrown on top of the plastic."

    Last week I did something that scared me. I stood in front of nearly 200 financial planners and I talked to them about why financial blogs are a good thing. I'm a confident writer. I've been doing this long enough that I know my strength and my limitations. I'm less confident as a speaker. I don't have time to pause to collect my thoughts. I'm not able to edit. I'm afraid of being trapped in a corner without being able to talk my way out. Basically, I'm scared to speak.

    It would be easy to simply refuse the chances that come my way. When somebody asks me to speak in front of a group, I could say "no". When radio and television stations call for an interview, I could say "no". But for the past two years, I've been following my own policy to say "yes" to new chances.

    To say "yes" is to live in fear. My goal is to continually improve myself to become better than I am today. One way to do that is to do the things that scare me, to take them on as challenges, and to learn from them—even if I fail.

    In mid-November, a local station asked me to appear on live television. "I realize it's short notice," the producer wrote, "but we'd love to have you on the show if you're available tonight." I was frightened. I thought about recent taped television interviews that I had hated. I was afraid of what might happen.

    But I also thought about the things that had gone right. I thought of how my speaking skills had improved over the past year. And then I thought of the book I was reading, a book that I had bought for $1.29 at the local store. The Magic of Thinking Big was a huge bestseller during the 1960s. Written by Dr. David Schwartz, a professor at Georgia State University, the book contains dozens of practical tips on how to take risks to achieve big goals. Schwartz argues that nobody will believe in you until you believe in yourself.

    So when the television producer asked if I wanted to appear on his show, I thought big. "Sure," I said. "I'll do it." I acted confidently, but on the inside I was frightened. What I needed was techniques to build up my confidence and to overcome my fear.