Before birth, babies can tell the difference between loud sounds and voices. They can even distinguish their mother's voice from that of a female stranger. But when it comes to embryonic learning(胎教), birds could rule the roost. As recently reported in The Auk: Ornithological Advances, some mother birds may teach their young to sing even before they hatch(孵化)。New-born chicks can then imitate their mom's call within a few days of entering the world.

    This educational method was first observed in 2012 by Sonia Kleindorfer, a biologist at Flinders University in South Australia, and her colleagues. Female Australian superb fairy wrens were found to repeat one sound over and over again while hatching their eggs, When the eggs were hatched, the baby birds made the similar chirp to their mothers—a sound that served as their regular “feed me!”call.

To find out if the special quality was more widespread in birds, the researchers sought the red-backed fairy wren, another species of Australian songbird. First they collected sound data from 67 nests in four sites in Queensland before and after hatching, Then they identified begging calls by analyzing the order and number of notes. A computer analysis blindly compared calls produced by mothers and chicks, ranking them by similarity.

    It turns out that baby red-backed fairy wrens also emerge chirping like their moms. And the more frequently mothers had called to their eggs, the more similar were the babies' begging calls. In addition, the team set up a separate experiment that suggested that the baby birds that most closely imitated their mom's voice were rewarded with the most food.

    This observation hints that effective embryonic learning could signal neurological(神经系统的) strengths of children to parents. An evolutionary inference can then be drawn.“As a parent, do you invest in quality children, or do you invest in children that are in need? ”Kleindorfer asks. “Our results suggest that they might be going for quality. ”

    If you have a chance to go to Finland, you will probably be surprised to find how “foolish” the Finnish people are.

    Take the taxi drivers for example. Taxis in Finland are mostly high-class Benz（奔驰）with a fare of two US dollars a kilometer. You can go anywhere in one, tell the driver to drop you at any place, say that you have some business to attend to, and then walk off without paying your fare. The driver would not show the least sign of anxiety.

    The dining rooms in all big hotels not only serve their guests, but also serve outside diners. Hotel guests have their meals free, so they naturally go to the free dining rooms to have their meals. The most they would do to show their good faith is to wave their registration card to the waiter. With such a loose check, you can easily use any old registration card to take a couple of friends to dine free of charge.

    The Finnish workers are paid by the hour. They are very much on their own as soon as they have agreed with the boss on the rate（价钱）. From then on they just say how many hours they have worked and they will be paid accordingly（相应地）.

    With so many loopholes（漏洞）in everyday life, surely Finland must be a heaven to those who love to take “petty advantages”. But the strange thing is, all the taxi passengers would always come back to pay their fare after they have attended to their business; not a single outsider has ever been found in the free hotel dining rooms. And workers always give an honest account of the exact hours they put in. As the Finns always act on good faith in everything they do, living in such a society has turned everyone into a real “gentleman”.

    In a society of such high moral practice, what need is there for people to be on guard against others? 

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    In the 1600's when the Spanish moved into what later was to become the southwestern United States, they came across the ancestors of the modern-day Pueblo, Hopi, and Zuni peoples. These ancestors, known variously as the basket makers, the Ancient ones, had lived in the area for at least 2000 years. They were an advanced agricultura people who used irrigation to help grow their drops.

    The Anasazi lived in houses constructed of earth and wood. Anasazi houses were originally built underground and were entered from the roof. But around the year 700 A. D., the Anasazi began to build their homes above ground and join them together into multistoried complexes, which the Spanish called villages. Separate underground rooms in these villages—known as kivas or holy places—were set aside for religious ceremonies. Each kiva had a fireplace and a hole that was believed to lead to the underworld. The largest villages had five stories and more than 800 rooms.

    The Anasazi family was ruled by women. The sacred objects of the family were under the control of the oldest female, but the actual ceremonies were conducted by her brother or son. Women owned the rooms in the village and the crops, once they were harvested. While still growing, crops belonged to the men who, in contrast to most other Native American groups, planted them. The women made baskets and pottery; the men wove cloth and made jewelry.

    Each village had two chiefs. The village chief dealt with land arguments and religious affairs. The war chief led the men in fighting during occasional conflicts that broke out with neithboring villages and directed the men in commnity building projects. The political and social organization of the Anasazi made it almost impossible for outer groups to conquer them.

    The online economy—from search to email to social media—is built in large part on the fact that consumers are willing to give away their data in exchange for products that are free and easy to use. The assumption behind this trade-off is that without giving up all that data, those products either couldn't be so good or would have to come at a cost.

    But a new working paper, released this week by Lesley Chiou of Occidental College and Catherine Tucker of MIT, suggests that the trade-off may not always be necessary. By studying the effects of privacy regulations in the EU, they attempted to measure whether the anonymization(匿名化) of search data hurts the quality of search results.

    Most search engines capture user data, including IP addresses and other data that can identify a user across multiple visits. This data allows them search companies to improve their algorithms(算法) and to personalize results for the user. At least, that's the idea. To determine whether storage of users' personal data improves search results, Chiou and Tucker looked at how search results from Bring and Yahoo differed before and after changes in the European Commission's rules on data retention(数据保存). In 2008 the Commission recommended that search engines reduce the period over which search engines kept user records. In response, Yahoo decided to strengthen its privacy policy by anonymizing user data after 90 days. In 2010 Microsoft changed its policy, and began deleting IP addresses associated with searches on Bring after six months and all data points intended to identify a user across visits after 18 months. In 2011 Yahoo changed its policy again, this time deciding to store personal data longer—for 18 months rather than 90 days—allowing the researchers yet another chance to measure how changes in data storage affected search results.

    The researchers then looked at data from UK residents' web history before and after the changes. To measure search quality, they looked at the number of repeated searches, a signal of dissatisfaction with search results. In all three cases, they found no statistically significant effect on search result quality following changes in data retention policy. In other words, the decision to anonymize the data didn't appear to impair the search experience. “Our results suggest that the costs of privacy may be lower than currently perceived,” the authors write, though they note that previous studies have come to different conclusions.

    The fence was long and high. He put the brush into the whitewash and moved it along the top of the fence. He repeated the operation. He felt he could not continue and sat down.

    He knew that his friends would arrive soon with all kinds of interesting plans for the day.

    They would walk past him and laugh. They would make jokes about his having to work on a beautiful summer Saturday. The thought burned him like fire.

    He put his hand into his pockets and took out all that he owned. Perhaps he could find some way to pay someone to do the whitewashing for him. But there was nothing of value in his pockets—nothing that could buy even half an hour of freedom. So he put the bits of toys back into his pockets and gave up the idea.

    At this dark and hopeless moment, a wonderful idea came to him. It filled his mind with a great, bright light. Calmly he picked up the brush and started again to whitewash.

    While Tom was working, Ben Rogers appeared. Ben was eating an apple as he walked along the street. As he walked along it, he was making noises like the sound of a riverboat. First he shouted loudly, like a boat captain. Then he said “Ding－Dong－Dong”,“Ding－Dong－Dong” again and again, like the bell of a riverboat. And he made other strange noises. When he came close to Tom, he stopped.

    Tom went on whitewashing. He did not look at Ben. Ben stared a moment and then said: “Hello! I'm going swimming, but you can't go, can you？”

    No answer. Tom moved his brush carefully along the fence and looked at the result with the eye of an artist. Ben came nearer. Tom's mouth watered for the apple, but he kept on working.

    Ben said, “Hello, old fellow, you've got to work, hey？”

    Tom turned suddenly and said, “Why, it's you, Ben! I wasn't noticing.”

     “Say—I'm going swimming. Don't you wish you could? But of course you'd rather work—wouldn't you? Of course you would.”

    Tom looked at the boy a bit, and said, “What do you call work？”

     “Why, isn't that work？”

    Tom went back to his whitewashing, and answered carelessly.

     “Well, maybe it is, and maybe it isn't. All I know is, it suits Tom Sawyer.”

     “Oh come, now, you don't mean to say that you like it？”

    The brush continued to move.

     “Like it? Well, I don't see why I shouldn't like it. Does a boy get a chance to whitewash a fence every day？”

    Ben stopped eating his apple. Tom moved his brush back and forth, stepped back to look at the result, added a touch here and there, and stepped back again. Ben watched every move and got more and more interested. Soon he said，“Say, Tom, let me whitewash a little.”

    Tom thought for a moment, and was about to agree, but he changed his mind.

     “No—no—it won't do, Ben. You see, Aunt Polly wants this fence to be perfect. It has got to be done very carefully. I don't think there is one boy in a thousand, maybe two thousand, that can do it well enough.”

     “No—is that so? Oh come, now—let me just try. Only just a little.”

“Ben, I'd like to, but if it isn't done right, I'm afraid Aunt Polly ”

     “Oh, I'll be careful. Now let me try. Say—I'll give you the core of my apple.”

     “Well, here—No, Ben, now don't. I'm afraid …”

     “I'll give you all of it.”

    Tom gave up the brush with unwillingness on his face, but joy in his heart. And while Ben worked at the fence in the hot sun, Tom sat under a tree, eating the apple, and planning how to get more help. There were enough boys. Each one came to laugh, but remained to whitewash. By the time Ben was tired, Tom sold the next chance to Billy for a kite; and when Billy was tired, Johnny bought it for a dead rat—and so on, hour after hour. And when the middle of the afternoon came, Tom had won many treasures.

    And he had not worked. He had had a nice idle time all the time, with plenty of company, and the fence had been whitewashed three times. If he hadn't run out of whitewash, Tom would have owned everything belonging to his friends.

    He had discovered a great law of human action, namely, that in order to make a man or a boy want a thing, it is only necessary to make the thing difficult to get.

    Have you ever looked out of the window of a passenger plane from 30,000 feet at the vast expanses of empty ocean and uninhabited land, and wondered how people can have any major effect on the Earth? I have. It is now becoming pretty clear that we are causing a great deal of damage to the natural environment. And the planes which rush us in comfort to destinations around the globe, contribute to one of the biggest environmental problems that we face today— global warming.

    As usual, people in the developing world are having to deal with problems created mainly by those of us in developed countries. Beatrice Schell, a spokeswoman for the European Federation for Transport and Environment says that, "One person flying in an airplane for one hour is responsible for the same greenhouse gas emissions（排放）as a typical Bangladeshi in a whole year." And every year jet aircraft produce almost as much carbon dioxide as the entire African continent does.

    There is a way of offsetting(抵消) the carbon dioxide we produce when we travel by plane. A company called Future Forests offers a service which can relieve the guilty consciences of air travelers. The Future Forest website calculates the amount of CO₂ you are responsible for producing on your flight, and for a small fee will plant a number of trees which will absorb this CO₂.

    Yesterday I returned to Japan from England, and was happy to pay Future Forests 25 pounds to plant the 3 trees which balance my share of the CO₂ produced by my return flight. Now the only thing making me lose sleep is jet lag.