1 . A new study has found no evidence that sunscreen, commonly used to reduce the risk of skin cancer, actually increases the risk.

Researchers from the University of Iowa based their findings on a review of 18 earlier studies that looked at the association between sunscreen use and melanomas(黑素瘤). They said that they found flaws in studies that had reported associations between sunscreen use and higher risk of melanoma.

Most health experts believe that by protecting the skin from the harmful effects of the sun, sunscreen helps prevent skin cancer, which is increasing in incidence (发生率) faster than any other cancer in the United States.

But questions have been raised about sunscreen and whether it may have the opposite effect, perhaps by allowing people to remain exposed to the sun longer without burning.

The researchers said that among the problems with some earlier studies is that they often failed to take into account that those people most at risk for skin cancer—people with fair skin and freckles(雀斑), for example—are more likely to use sunscreen. As a result, it may appear that sunscreen users get cancer more often.

The studies, which generally relied on volunteers to recall their sunscreen use, were also unable to prove how well the products had been applied, said the new study.

2 . Bitcoin and other so-called cryptocurrencies (加密货币)have been all over the news lately. Apparently, the idea of money that’s not tied to a specific bank—or a specific country—is appealing to many. But it’s worth remembering that the banking system that we now all live with is just that： A modern invention. Not so long ago, money was almost always created and used locally, and bartering was common. (In fact, it still is common among many online local networks, like the Buy Nothing Project.).

In the past, money’s makeup varied from place to place, depending on what was considered valuable there. So while some of the world’s first coins were made from a naturally occurring hybrid of gold and silver called electrum (银金矿)，objects other than coins have served as currency, including beads, ivory, livestock, and cowrie shells. In West Africa, bracelets of bronze or copper were used as cash, especially if the transaction was associated with the slave trade there. Throughout the colonial period, tobacco was used to replace coins or paper bills in Virginia, Maryland and North Carolina, even though it was used elsewhere in the colonies and extensively throughout Europe and the U. K.

Today, on an island in the Pacific, a specific type of shell still serves as currency—and some people there are even hoarding(贮存)it, just like Bitcoin moguls, convinced that one day, it will make them wealthy beyond imagination. On Malaita, the most-populated island that’s part of the Solomon Islands, shells are accepted at most places in exchange for goods.

”How much tuna(金枪鱼)you can get for your shells depends on their color and shape,“ Mary Bruno, a shop owner from the small town of Auki, on Malaita, told Vice. ”One strip of darker shells might get you about two cans of smaller tuna, but the red ones are worth more. For the red ones, one strip might get enough tuna to feed a big family for a long time.“

Just like a mint that creates coins, there’s only one place on the island where the shells, which are polished and strung together to form 3-foot-long ropes, are made. The strips of red, white, and black shells all come from Langa Langa Lagoon, where artificial islands were long-ago built by locals to escape from the island-dwelling cannibals. Once marooned(困住)out on their islands, locals needed a currency to use among themselves, and so the shell currency was born.

Using shells for money was common throughout the Pacific islands as late as the early 1900s, but Malaita is unique in that they are still used today. And just like cryptocurrencies, there are those who think the islanders are smart to invest in this type of money, which is reported to have risen in value over the last three decades. It might seem strange to hoard a bunch of processed, strung-together shells, but what is a pile of dollars? Just a specially printed piece of paper and hemp that we’ve assigned value to—and probably less durable over time than those shells.

3 . George Prochnik would like the world to put a sock in it. He makes his case in a new book, listenning for Meaning in a World of Noise, here he explains himself (using his indoor voice):

“We’ve become so accustomed to noise, there’s about almost a deep prejudice against the idea that silence might be beneficial. If you tell someone to be quiet, you sound like an old man. But it’s never been more important to find continuing quiet. Silence focuses us, improves our health, and is a key to lasting peace and satisfaction.”

“We need to excite people about the sounds you start to hear if you merely quiet things down a little. During a Japanese tea ceremony, the smallest sounds becomes a kind of art—the spoons making a light ringing sound on a bowl, the edges of a kimono(和服)brushing against the floor.”

“Dear people are very attentive(专注的)in almost every aspect of life. If two deaf people are walking together, using sign language, they constantly watch out for each other and protect each other by paying steady attention to the other. They are connected yet also fully aware of their surroundings. Even deaf teenagers! We in the hearing world can learn from them. If we remove the powerful blasts(一阵阵)of noise, we become aware of an extraordinarily rich world around us—of little soft sounds and the sound of footsteps, of bird songs and ice cracking(开裂声). It’s astonishing how beautiful things sound when you can really listen. ”

4 . When the explorers first set foot upon the continent of North America, the skies and lands were alive with an astonishing variety of wildlife. Native Americans had taken care of these precious natural resources wisely. Unfortunately, it took the explorers and the settlers who followed only a few decades to decimate a large part of these resources. Millions of waterfowl (水禽) were killed at the hands of market hunters and a handful of overly ambitious sportsmen. Millions of acres of wetlands were dried to feed and house the ever-increasing populations, greatly reducing waterfowl habitat.

In 1934, with the passage of the Migratory Bird Hunting Stamp Act (Act), an increasingly concerned nation took firm action to stop the destruction of migratory (迁徙的) waterfowl and the wetlands so vital to their survival. Under this Act, all waterfowl hunters 16 years of age and over must annually purchase and carry a Federal Duck Stamp. The very first Federal Duck Stamp was designed by J.N. “Ding” Darling, a political cartoonist from Des Moines, lowa, who at that time was appointed by President Franklin Roosevelt as Director of the Bureau of Biological Survey. Hunters willingly pay the stamp price to ensure the survival of our natural resources.

About 98 cents of every duck stamp dollar goes directly into the Migratory Bird Conservation Fund to purchase wetlands and wildlife habitat for inclusion into the National Wildlife Refuge System — a fact that ensures this land will be protected and available for all generations to come. Since 1934, better than half a billion dollars has gone into that Fund to purchase more than 5 million acres of habitat. Little wonder the Federal Duck Stamp Program has been called one of the most successful conservation programs ever initiated.

What does the underlined word “decimate” mean in the first paragraph?

5 . When I was 9, we packed up our home in Los Angeles and arrived at Heathrow, London on a gray January morning. Everyone in the family settled quickly into the city except me. Without my beloved beaches and endless blue—sky days, I felt at a loss and out of place. Until I made a discovery.

Southbank, at an eastern bend in the Thames, is the center of British skateboarding, where the continuous crashing of skateboards left your head ringing .I loved it. I soon made friends with the local skaters. We spoke our own language. And my favorite: Safe. Safe meant cool. It meant hello. It meant don’t worry about it. Once, when trying a certain trick on the beam(横杆), I fell onto the stones, damaging a nerve in my hand, and Toby came over, helping me up: Safe, man. Safe. A few minutes later, when I landed the trick, my friends beat their boards loud, shouting: “ Safe! Safe! Safe!” And that’s what mattered—landing tricks, being a good skater.

When I was 15, my family moved to Washington. I tried skateboarding there, but the locals were far less welcoming. Within a couple of years, I’d given it up.

When I returned to London in 2004, I found myself wandering down to Southbank, spending hours there. I’ve traveled back several times since, most recently this past spring. The day was cold but clear: tourists and Londoners stopped to watch the skaters. Weaving(穿梭)among the kids who rushed by on their boards, I found my way to the beam. Then a rail—thin teenager, in a baggy white T—shirt, skidded(滑)up to the beam. He sat next to me. He seemed not to notice the man next to him. But soon I caught a few of his glances. “I was a local here 20 years ago,” I told him. Then, slowly, he began to nod his head. “Safe, man. Safe.”

“Yeah,” I said. “Safe.”

6 . We live in a town with three beaches. There are two parts less than 10 minutes’ walk from home where neighborhood children gather to play. However, what my children want to do after school is pick up a screen — any screen — and stare at it for hours. They are not alone. Today’s children spend an average of four and a half hours a day looking at screens, split between watching television and using the Internet.

In the past few years, an increasing number of people and organisations have begun coming up with plans to counter this trend. A couple of years ago film-maker David Bond realised that his children, then aged five and three, were attached to screens to the point where he was able to say “chocolate” into his three-year-old son’s ear without getting a response. He realised that something needed to change, and, being a London media type, appointed himself “marketing director from Nature”. He documented his journey as he set about treating nature as a brand to be marketed to young people. The result was Project Wild Thing, a film which charts the birth of the World Network, a group of organizations with the common goal of getting children out into nature.

“Just five more minutes outdoors can make a difference,” David Bond says. “There is a lot of really interesting evidence which seems to be suggesting that if children are inspired up to the age of seven, then being outdoors will be on habit for life.” His own children have got into the habit of playing outside now: “We just send them out into the garden and tell them not to come back in for a while.”

Summer is upon us. There is an amazing world out there, and it needs our children as much as they need it. Let us get them out and let them play.

7 . Over the last seven years, most states have banned texting by drivers, and public service campaigns have tried a wide range of methods to persuade people to put down their phones when they are behind the wheel.

Yet the problem, by just about any measure, appears to be getting worse. Americans are still texting while driving, as well as using social networks and taking photos. Road accidents, which had fallen for years, are now rising sharply.

That is partly because people are driving more, but Mark Rosekind, the chief of the National Highway Traffic Safety Administration, said distracted(分心)driving was “only increasing, unfortunately.”

“Big change requires big ideas.” he said in a speech last month, referring broadly to the need to improve road safety. So to try to change a distinctly modern behavior, lawmakers and public health experts are reaching back to an old approach: They want to treat distracted driving like drunk driving.

An idea from lawmakers in New York is to give police officers a new device called the Textalyzer. It would work like this: An officer arriving at the scene of a crash could ask for the phones of the drivers and use the Textalyzer to check in the operating system for recent activity. The technology could determine whether a driver had just texted, emailed or done anything else that is not allowed under New York’s hands-free driving laws.

“We need something on the books that can change people’s behavior,” said Félix W. Ortiz, who pushed for the state’s 2001 ban on hand-held devices by drivers. If the Textalyzer bill becomes law, he said, ”people are going to be more afraid to put their hands on the cell phone.“

8 . Many people believe that working to the maximum is the secret to success, but research has found that moderation(适度) also gets results on the job.

In a study led by Ellen Langer of Harvard University, researchers asked people to translate sentences into a new a made-up language. Subjects who practiced the language moderately beforehand made fewer errors than those who practiced extensively or not at all. High levels of knowledge can make people too attached to traditional ways of viewing problems across fields the arts, sciences, and politics. High conscientiousness is related to lower job performance, especially in simple jobs where it doesn’t pay to be a perfectionist.

How long we stay on the clock and how we spend that time are under careful examination in many workplaces. The young banker who eats lunch at his desk is probably seen as a go-getter, while his colleagues who chat over a relaxed conference-room meal get dirty looks from the corner office. “People from cultures that value relationships more than ours does are shocked by the thought of eating alone in front of a computer”, says Art Markman, a professor of psychology at the University of Texas, Austin. Social interaction has been shown to lift mood(情绪) and get people thinking in new directions and in ways that could help improve any post-lunch effort.

Markman also promotes off-task time. “Part of being a good thinker is experiencing things that are seemingly unrelated to what you are working on at the moment but give you fresh ideas about your work,” he says. “Also, there is a lot of research showing that a positive mood leads to higher levels of productivity and creativity. So, when people do things to increase their life satisfaction, they also make themselves more effective at work.”

9 . A machine can now not only beat you at chess, it can also outperform you in debate. Last week, in a public debate in San Francisco, a software program called Project Debater beat its human opponents, including Noa Ovadia, Israel’s former national debating champion.

Brilliant though it is, Project Debater has some weaknesses. It takes sentences from its library of documents and prebuilt arguments and strings them together. This can lead to the kinds of errors no human would make. Such wrinkles will no doubt be ironed out, yet they also point to a fundamental problem. As Kristian Hammond, professor of electrical engineering and computer science at Northwestern University, put it: “There’s never a stage at which the system knows what it’s talking about.”

What Hammond is referring to is the question of meaning, and meaning is central to what distinguishes the least intelligent of humans from the most intelligent of machines. A computer works with symbols. Its program specifies a set of rules to transform one string of symbols into another. But it does not specify what those symbols mean. Indeed, to a computer, meaning is irrelevant. Humans, in thinking, talking, reading and writing, also work with symbols. But for humans, meaning is everything. When we communicate, we communicate meaning. What matters is not just the outside of a string of symbols, but the inside too, not just how they are arranged but what they mean.

Meaning emerges through a process of social interaction, not of computation, interaction that shapes the content of the symbols in our heads. The rules that assign meaning lie not just inside our heads, but also outside, in society, in social memory, social conventions and social relations. It is this that distinguishes humans from machines. And that’s why, however astonishing Project Debater may seem, the tradition that began with Socrates and Confucius will not end with artificial intelligence.