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. ”

    Whether you're up for a Crocodile Dundee's adventure or you'd just like a taste of the Australian sun, the beaches in and around Sydney can offer you all that and more.

Sydney Beach

    Sydney Beach is located at Sydney's northernmost tip on an extension(延伸) of land ending at Palm Beach. Before checking out the golden sand, take a quick tour of the houses of millionaires from the art and film industries.

Palm Beach

    Only about an hour from downtown Sydney, Palm Beach offers a long stretch(延伸) of clean sand and water. With parking near the center of the beach, that leaves the rest of it as a peaceful location with a sparse population, from which you can go surfing but take care — without the huge crowds of other Sydney's beaches, Palm Beach doesn't afford quite the safety level to be found elsewhere. Volunteer lifesavers are on duty only on weekends and holidays.

Bondi Beach

    For the famous beach, Bondi Beach has to be your choice. Parking is difficult to find even on slow days, so consider taking public transport to this world—known beach in the eastern Sydney suburbs. Easily reachable by taxi, bus, and rail, Bondi Beach offers sun bathing, swimming, snorkeling, and all sorts of water sports fun. If you're in the mood for a bit of exercise, two scenic coastal walks will afford you great views and sights along the shore. Take in views from Mackenzie's Point. It starts at Bondi and heads south to Bronte Beach. But don't try to swim in Mackenzie's Bay — it holds dangers such as hidden rocks.

Bronte Beach

    Your second choice for a scenic coastal walk covers a few miles and takes you from Bronte Beach to Waverly Cemetery, where many famous Australians are buried, including the poet Henry Lawson.

    Devon, 17, is used to paying her own cell phone and car expenses. But lately it's been harder. The family she baby-sits for hasn't been calling as much as usual and she couldn't find a job over the summer. Devon's dad said it's a sign of the tough economy. He told her he's feeling the pinch too and that he had to use her college fund to pay the loan(货款).

    This kind of money troubles isn't strange to common families these days. In fact, it's hard to avoid news about the economy on the screen of the TV or the computers recently. It can seem a bit worry and some families are hit really hard.

    For most people, the big problem is that things cost more at a time when they have less money to spend. But higher prices aren't the only problem. Many people are having a tough time making payments on some types of home loans.

    Therefore, some families are cutting back on what they spend.  For example, eating out less, staying home instead of going on vacation, moving to a less expensive house and so on.

    However, as discouraging as things may seem now, the good news is that the economy always gets back on track after a while. Jobs may be hard to find, but the slow economy can open up new opportunities. The couple Devon babysat for might cut back on evening's out, but they could be interested in hiring her for after-school care. Perhaps it's time to sell her old toys and baby gear (设备)in the basement(地下室) or help others sell these items online if she is good at it. She could charge them a fee to sell their old stuff(东西).

    E-mail systems at thousands of companies and government offices around the world were attacked by a virus(病毒)called “Melissa” that disguises(伪装)itself as an “important message from a friend. In spite of a weekend of warnings，more than 50 000 computers at about 100 places around the world have been attacked by the virus，computer security experts said on Monday.

    The virus began to show up last Friday and spread rapidly on Monday by making computers fire off dozens of infected(被传染的)e-mails. Although the virus causes no serious damage to a computer，its effect was far reaching.

    To make matters worse，a similar virus called “Papa” was discovered on Monday. Papa is programmed to send out even more infected e-mails than Melissa.

    The Melissa virus comes in the form of an e-mail，usually containing the subject line“Important Message”. It appears to be from a friend. The body of the e-mail message says，“Here is that document you asked for...,don't show it to anyone else.” Attached(附)to the message is a document file.

    Once the user opens that file，the virus digs into the user's address book and sends infected documents to the first 50 addresses. E-mails from the Papa virus include an attached spreadsheet(电子数据文件)file. When the user opens that file，the virus sends 60 infected e-mails.

    The reason why this is spreading so fast is that you are getting it from people you know. You should never open documents or attachments from people you don't know. People who get an unexpected e-mail with the “important message” subject line should delete it immediately and not open the message.

    On Friday, the Food and Drug Administration (FDA) released two proposals to improve food safety. The regulations are a response to a series of recent foodborne illnesses. The FDA hopes these new rules will prevent problems of food in the earliest period of production, before the contaminated（受污染的）food causes consumers to get sick.

    Over the past decade, foodborne illnesses have caused many people to get sick. Food like spinach（菠菜）, ground beef and cantaloupes（甜瓜）has been sent back to producers, because it is bound to contain germs and bacteria that cause illnesses.

    Among the most common problems are dangerous bacteria that cause stomach pains and food poisoning. Often these illnesses occur when food is undercooked or improperly prepared. While not all illnesses are reported, the FDA estimates that nearly 130,000 Americans a year are hospitalized for food-related problems.

    The two new rules proposed by the FDA are called Preventive Controls for Human Food and Standards for Produce Safety. Each rule is described in detail on the FDA's website. Readers can submit comments, which the FDA will use as feedback to mike future adjustments to the proposals.

    The first rule demands manufacturers should have formal plans for preventing contamination and for fixing problems when contamination occurs. This regulation is applied to food produced in the US and overseas.

    The second rule k specific to food that is eaten raw. It requires strict standards of growing harvesting, and packing fruit and vegetables. Workers must make sure the materials used in soil are safe and free of contamination.

    The FDA believes these new rules will not just improve Americans' health but also make a positive economic impact. The regulations can lead to major savings in medical costs for people who get sick because of the contamination food.

    If manufacturers are able to fix problems at source, they will prevent future issuer However, putting the proposals into action will lake lime and money.

    The human face is a remarkable piece of work. The astonishing variety of facial features helps people recognize each other and is vital to the formation of complex societies. So is the face's ability to send emotional signals, whether through an unconscious red face or the artifice of a false smile. People spend much of their waking lives reading faces, for signs of attraction, hatred, trust and fraud. They also spend plenty of time trying to hide true feelings or intentions.

    Technology is rapidly catching up with the human ability to read faces. In America facial recognition is used by churches to track worshippers' attendance; in Britain, by retailers to spot past shoplifters. In China, it confirms the identities of ride-hailing drivers, permits tourists to enter attractions and lets people pay for things with a smile. Apple's new iPhone is expected to use it to unlock the home screen.

    Set against human skills, such applications might seem incremental(增值的). Some breakthroughs, such as flight or the Internet, obviously transform human abilities; facial recognition seems merely to encode(编码)them. Although faces are unique to individuals, they are also public, so technology does not, at first sight, interfere with something that is private. And yet the ability to record, store and analyze images of faces cheaply, quickly and on a vast scale promises one day to bring about fundamental changes to opinions of privacy, fairness and trust.

    Start with privacy. One big difference between faces and other biometric data, such as fingerprints, is that they work at a distance. Anyone with a phone can take a picture for facial-recognition programs to use. Facebook's bank of facial images cannot be used by others, but the Silicon Valley giant could obtain pictures of visitors to a car showroom, say, and later use facial recognition to serve them ads for cars. Law-enforcement agencies now have a powerful weapon in their ability to track criminals, but at enormous potential cost to citizens' privacy.

    The face is not just a name-tag. It displays a lot of other information—and machines can read that, too. Again, that promises benefits. Some firms are analyzing faces to provide automated diagnoses of rare genetic conditions, far earlier than would otherwise be possible. Systems that measure emotion may give autistic(孤独症的)people a grasp of social signals they find difficult.