Parents who help their children with homework may actually be bringing down their school grades. Other forms of parental involvement, including volunteering at school and observing a child's class, also fail to help, according to the most recent study on the topic.

    The findings challenge a key principle of modern parenting where schools expect them to act as partners in their children's education. Previous generations concentrated on getting children to school on time, fed, dressed and ready to learn.

    Keith Robinson, the author of the study, said, "I really don't know if the public is ready for this but there are some ways parents can be involved in their kids' education that leads to declines in their academic performance. One of the things that was consistently negative was their parents' help with homework." Robinson suggested that may be because parents themselves struggle to understand the tasks."They may either not remember the material their kids are studying now, or in some cases never learnt it themselves, but they're still offering advice."

    Robinson assessed parental involvement performance and found one of the most damaging things a parent could do was to punish their children for poor marks. In general, about 20% of parental involvement was positive,  about 45% negative and the rest statistically insignificant.

    Common sense suggests it was a good thing for parents to get involved because "children with good academic success do have involved parents", admitted Robinson. But he argued that this did not prove parental involvement was the root cause of that success. "A big surprise was that Asian-American parents whose kids are doing so well in school hardly involved. They took a more reasonable approach, conveying to their children how success at school could improve their lives."

    Advances in artificial intelligence and the use of big data are changing the way many large companies recruit (招募) entry level and junior management positions. These days, graduates' CVs may well have to impress an algorithm (算法) rather than an (human resources) manager.

    While algorithms supposedly treat each application equally, experts are divided about whether so-called robo-recruitment promises an end to human prejudice in the selection process —or whether it may in fact add to it.

    “AI systems are not all equal,” says Loren Larsen, chief technology officer for HireVue, which has developed an automated video interview analysis system. “I think you have to look at the science team behind the work,” says Mr Larsen.

    The problem, experts say, is that to find the best candidates an algorithm has first to be told what “good” looks like in any given organization. Even if it is not given criteria that seem discriminatory, a powerful machine-learning system will quickly be able to copy the characteristics of existing workers. If an organization has favoured white male graduates from well-known universities, the algorithm will learn to select more of the same.

    The growing dependence on automation to judge suitability for everything from a loan to a job worries Yuriy Brun, an associate professor specializing in software engineering. “It takes a lot of the time for a company to put out software but it doesn't know if it is discriminatory” he says. Prof Brun explains that, considering the use of big data, algorithms will unavoidably learn to discriminate.

    Many of those working with robo-recruiters are more optimistic. Kate Glazebrook, the leader and co-founder of Applied, a hiring platform, says her task is to encourage hiring manager to move away from such indicators of quality as schools or universities and move to more evidence-based methods. When candidates complete tests online, Applied hides their names and shows the tests the candidates have completed, question by question, to human assessors. Every stage of the process has been designed to remove prejudice.

    With the same aim, Unilever decided in 2016 to switch to a more automated process for its graduate-level entry programme. Unilever worked with HireVue, Amberjack, which provides and advises on automated recruitment processes, and Pymetrics, another high volume recruitment company, which developed a game-based test in which candidates are scored on their ability to take risks and learn from mistakes, as well as on emotional intelligence. Unilever says the process has increased the ethnic diversity of its listed candidates and has been more successful at selecting candidates who will eventually be hired.

    “The things that we can do right now are impressive, but not as impressive as we're going to be able to do next year or the year after,” says Mr Larsen.

    Still, robo-recruiters must be regularly tested in case prejudice has occurred without anyone realizing it, says Frida Polli, the leader and co-founder of Pymetrics. “The majority of algorithmic tools are most likely causing prejudice to continue existing. The good ones should be examined.”

    Birds' feathers are some of the most strikingly variable animal characteristics that can be observed by the eyes. The patterns that we see in birds' feathers are made up of combinations of scales, bars, and spots.

    We already know why birds have colored feathers. Generally, the color of feathers may protect a bird from being noticed by the enemy in the environment, or it can make a bird more appealing to potential mates by helping them to stand out. These aspects are well known. A greater mystery has been how the patterns are created.

    Dr. Ismael Galván and his team studied the color of feathers to see what types of colors were present in birds' complex feather patterns. The study shows they mainly consist of two types of colors: melanin（黑色素）, which produce a range of black, grey, brown, and orange color, and carotenoids（类胡萝卜色素）, which are used to create brighter colors.

    Birds cannot produce carotenoids on their own. For feathers with bright colors, birds must consume food items that contain these paints, and the carotenoids circulate through the blood and to the feather. Melanin, on the other hand, is produced by special cells in the birds' bodies.

    The team found that about 32% if the species studied have complex color patterns, with the vast majority of these complex patterns produced by melanin rather than carotenoids. If the birds were artists, they would use carotenoids as a broad brush to produce color patches, with melanin as a detail paint brush to produce more complex designs.

    But a few birds are exceptions to this rule: Three bird families do have complex patterns without melanin.

    There was a time in the 1960's and 1970's when some people believed that coffee would replace tea as Britain's favourite drink, but that did not happen, and today, tea remains Britain's favourite drink.

    To say that the British are fond of tea is something of an understatement. From the Royal(皇室的) Family down to the homeless and the out-of-work, tea is more than just a pleasure. It is an important part of life!

    The popularity of tea in the United Kingdom has a long history. It was in 1657 that Thomas Garway, the owner of a coffee house, sold the first tea in London. The drink soon became popular as another choice besides coffee.

    In those days, however, tea was not something for anyone. For a century and a half, it remained an expensive drink. Many bosses served a cup of it to their workers in the middle of the morning, thus inventing a lasting British tradition, the “tea break”. But as a social drink outside the workplace, tea was served for the nobility(贵族) and for the growing middle classes. Among those who had the money for tea, it became very popular as a drink to be enjoyed in cafés and “tea gardens”.

    It was the 7th Duchess of Bedford who, in around 1800, started the popular “afternoon tea”, which took place at about four o'clock. At about the same time, the Earl of Sandwich popularized a new way of eating bread with something (e. g. jam) between them, and before long, a small meal at the end of the afternoon with tea and sandwiches had become part of a way of life.

    As tea became much cheaper during the nineteenth century, its popularity spread right through British society. In working-class households, it was served with the main meal of the day, eaten when workers returned home after a day's labour. This meal has become known as “high tea”.

    Today, tea can be drunk at any time of day. Most people in Britain drink tea for breakfast. The mid-morning “tea break” is an institution in British offices and factories. Later in the day, “afternoon tea” is still a way of life in the south of England and among the middle classes, while “high tea” has remained a tradition in the north of Britain.

    On a recent spring morning. Susan Alexander, a retired government intelligence analyst, left her Maryland home, climbed into her Volkswagen Passat and drove about three miles to pick up two strangers. She battled rush-hour traffic on the Capital Beltway and George Washington Memorial Parkway before dropping them off at Reagan National Airport. She didn't earn a cent for her trouble, and that was the point.

    Alexander is a member of the Silver Spring Time Bank-one of more than 100 such exchanges around the world trying to build community by exchanging time credits for services instead of dollars and cents. "I have time," she said. "I like giving the gift of time to other people."

    In Alexander's case, passengers Mary and Al Liepold were grateful for the ride, but it wasn't charity. Mary, a retired writer and editor for nonprofit organizations, used time credits she banked for editing work and baking. Senior citizens who don't drive, the Liepolds cashed in their credits to catch a flight to Montreal for a five-day vacation.

    Without money changing hands or shifting between virtual accounts, the airport drop-off was more like a coffee party than a taxi ride. Driver and passengers chatted about projects they've completed for the time bank, and no one raised an eyebrow when Mary said she likes "to avoid the conventional economy."

    "The beauty of this is that you make friends," Mary Liepold said. "You don't just get services."

    The Silver Spring Time Bank formed in 2015 and has about 300 members, said co-founder Mary Murphy. Last year, she said, l,000 hours were exchanged for basic home repairs, dog walking, cooking and tailoring, among other services, without the exchange of money. "You get to save that money that you would have spent," she said. "You get to meet somebody else in your community and get to know that person. That's a bonus that's part of an exchange."

    A deal performed partly to make friends would seem to go against classical economics and one of Benjamin Franklin's most memorable sayings: "Time is money." To those at the forefront of modem time-banking, that is the appeal.

    A famous Anglican Church stands in a quiet corner of Dunedin in New Zealand's South Island. Built in 1865, it is the city's oldest church still in use. Countless couples have gathered here to marry. It's where morning tears are shared, friendships formed and comfort given during times of loss.

    As with many churches, its walls are graced with a collection of beautiful stained-glass windows. Known as the "John Allen window", one window portrays the short life of a local man, John Allen, who died in 1915 in the Gallipoli campaign in Turkey.

    John was the son of Sir James Allen, who as Minister of Defense, helped plan and administer New Zealand's World War I strategy, which saw 100,000 troops sent to fight. With the war over and his son dead, Sir James chose to install a window in the church, with which the Allen family had strong ties.

    Divided into two parts, one depicts (描绘) St. George, the patron saint (守护神) of soldiers, while the other has an angel of peace, along with the words at the bottom, "John Hugh All Gallipoli, 6th June, 1915". Two trees with local birds on the branches can be seen and a kiwi walks at the bottom- reminders that John was a lover of birds.

    "There are many war memorials in the church," says the church. "However the 'John Allen window' stands out; it touches people because of the beautiful design, the New Zealand birds and because John's story, of a life so full of promise ending tragically in the war, reflects the lives and stories of so many others involved in World War I."