In many countries, schools have long summer holidays, with shorter holidays in between. However, a new report suggests shortening school holidays to stop children forgetting what they have learnt during the long summer break. Instead of three school terms, it says, there should be five eight-week terms. And there should be just four weeks off in the summer, with a two-week break between the other terms.

    Sonia Montero has two children at primary school and works full-time. She supports the idea. “The kids,” she says, “have much longer holidays than me and I can't afford to take several weeks off work, so I need someone to take care of them. But nobody wants the work in the summer months — they all have holidays of their own.”

    Not surprisingly, some young people disagree. Student Jason Panos says “It's a stupid idea. I would hate staying at school in the summer. It's unfair, too. The people who suggest this had long school holidays when they were young, but now they want to stop us enjoying the summer. The kids in Spain and America have much longer holidays than here, but they don't forget everything they've learnt in a few months.”

    Nadia Salib agrees. “Sure,” she says, “the first week at school after the summer is never easy, but you soon get back into it. The real problem round here is that kids get bored after so many weeks out of school, and then some of them start causing trouble. But the answer is to give them something to do, not make everyone stay in school longer.”

    Augusto Esquivel is a sculptor who, in his own words, is “crazy with comparisons of reality and potential and the balance between them.” Perhaps the best example of what he's talking about are his most famous creations: the suspended(悬挂的) button sculptures.

Made entirely from buttons hanging on various lengths of string, Esquivel's sculptures are made to look like common objects: a piano, a gumball machine, and even a toilet. If it wasn't for the clear string hanging above, these objects, these sculptures, would look solid, yet you can put your hands right through them. The process starts with him deciding on a subject and setting the acrylic （丙烯酸树脂）from where the buttons are being suspended. He buys buttons of different shapes and sizes, paints them with spray paint, and carefully hangs them. After that, it's a manner of hanging each individual button, which takes a lot of time. For his piano, for example, he individually hung over 60 pounds worth of tiny buttons.

Esquivel's sculptures, while mostly housed inside art galleries, perfectly capture one of the main principles of street art: something that is eye-catching and something that invites interaction. Often the best sculptures outside the art galleries aren't the ones behind guards and fencing, but the ones people can go right up to and touch. In Vancouver, a series of laughing old men are attracting people for pictures and to just generally hang around, but the people who simply walk by and see the sculptures almost always leave with a smile on their face. That's good street art: it draws the viewer in rather than relying on a gallery to draw in an audience and point them to certain pieces.

Esquivel's art is not only a presentation of talent, something that mentions larger philosophical questions, like the ones he stated above, but also just the right combination of interesting idea and painstaking work. One can look at his work in a critical way, or simply appreciate his idea and execution(艺术品的制作).

Authors (作者)

    Alexandru Micu: Author

    ZME Science author profile | e-mail: alex@zmescience.com

    Main focus: technology, biology

    Curiosity (好奇心) is what drives Alex forward-his interest in learning more about the planet being matched only by his ability to discuss things with a light heart. Alex tries to make others more interested in special science and technology. He does things in his own way.

    Dragos Mitrica: Author

    ZME Science author profile | e-mail: dragos@zmescience.com

    Main focus: wheather

    Dragos loves nature, and does everything he can to understand it. This interest led him to many unexpected places in his life, and now, he mainly studies and understands how ancient (古代的) weather changed, and what this means for the future.

    Henry Conrad: Author

    ZME Science author profile | e-mail: henrykconrad@gmail.com

    Main focus: technology

    Henry Conrad is a game developer from Albuquerque, New Mexico. Whenever he's not working or reading the latest tech news, he enjoys writing about the latest inventions and technology, which benefits (有益) him a lot. It helps him find rich writing materials (材料).

    Mihai Andrei: Editor-in-chief

    ZME Science author profile | e-mail: andrei@zmescience.com

    Main focus: geophysics, environment

    Andrei has put a lot of sweat and tears into ZME Science ever since he was a student. He is always looking for the most interesting subjects, presenting them in a way that everybody can understand. He believes that education is the key towards a better future and he tries to persuade people to become better persons of the planet. His background is in Geology and Geophysics, but now, he focuses more on environmental studies.

    Sandra Cisneros was born in Chicago in 1954 to a Mexican American family. As the only girl in a family of seven children, she often felt like she had "seven fathers ", because her six brothers, as well as her father, tried to control her. Feeling shy and unimportant, she hid herself into books. Despite her love of reading, she did not do well in elementary school because she was too shy to participate.

    In high school, with the encouragement of one particular teacher, Cisneros improved her grades and worked for the school literary magazine. Her father encouraged her to go to college because he thought it would be a good way for her to find a husband. Cisneros did attend college, but instead of searching for a husband, she found a teacher who helped her join the famous graduate writing program at the University of Iowa. At the University's Writers' Workshop, however, she felt lonely—a Mexican American from a poor neighborhood among students from wealthy families. The feeling of being so different helped Cisneros find her "creative voice".

    "It was not until this moment when I considered myself truly different that my writing acquired a voice. I knew I was a Mexican woman, but I didn't think it had anything to do with why I felt so much imbalanced in my life, but it had everything to do with it! That's when I decided I would write about something my classmates couldn't write about."

    Cisneros published her first work, The House on Mango Street , when she was twenty-nine. The book tells about a young Mexican American girl growing up in a Spanish-speaking area in Chicago, much like the neighborhoods in which Cisneros lived as a child. The book won an award in 1985 and has been used in classes from high school through graduate school level. Since then, Cisneros has published several books of poetry, a children's book, and a shortstory collection.

    China officially informed the World Trade Organization on Tuesday that it will ban the import of 24 different types of solid waste by the end of this year as part of a campaign to deal with environmental pollution and protect people's health.

    In response to growing public concerns over the potential environmental and health danger caused by the increasing amounts of solid waste imported into the country for recycling and treatment, China passed a special law in 1995 to control imports of waste materials, such as plastics, slag from steelmaking, unsorted scrap paper and discarded textile materials.

    A year later, the country published a list for solid waste imports and began implementing a permit system to control the import volumes and types of waste imported.

    However, due to the lack of effective supervision（监管）and the failure of relevant departments to fulfill their duties, solid waste imports have not been effectively controlled.

    So far, China is the world's largest importer of solid waste. According to the Ministry of Environmental Protection, China imported 7.3 million metric tons of plastic waste worth $3.7 billion in 2016, accounting for 56 percent of global imports of solid waste.

    Correct recycling of solid waste materials is an important part of the global economy, and moderate imports of scrap plastic, scrap paper and scrap rubber products, such as vehicle tires, can to some extent, make up for China's shortage of various raw materials.

    However, the lack of supervision has resulted in the country's severe soil and environmental worsening.

    Given that China's continuing efforts to push for industrial transformation and upgrading have resulted in a noticeable decline in the demand for the materials recycled from solid waste imports. It is right for the country to restrict such imports for the sake of the environment and public health, and to better adapt to the changed industrial structure.

    Earlier this month a study showed that bees can teach themselves to play football. They can learn by watching and, rather than copy what they have seen, change it to make it better. Bees also have a clever trick for helping their friends find lunch. New research shows that bees leave smelly little footprints on flowers that help them know what flowers they and their family members have recently visited.

    The discovery was made by scientists from University of Bristol who report these smelly footprints help bees distinguish  between their own scent(气味), the scent of a relative and the scent of a stranger. And by using this ability, bees can improve their success at finding good sources of a food and avoid flowers that have already been visited and mined of nutrients.

    The Bristol team performed three separate experiments with bumblebees(大黄蜂)in which they were repeatedly exposed to rewarding and unrewarding flowers at the same time that had footprints from different bees attached to them. Each flower type either carried scent -marks from bumblebees of differing relatedness or were unmarked. The marks were either the bee's own marks, sisters from their nest, or strangers from another nest.

    The study shows that not only can bumblebees tell the marks of their own nest mates from strangers, but they can also discriminate between the smell of their own footprints and those of their nest mate sisters, which could help them to remember which flowers they have visited recently. But it doesn't explain how they use that in the wild. They may detect the footprints of their friends and keep moving on, since that flower may be tapped out. Or they may smell a bit of familiar foot smell and dive in, seeing it as a marker that nectar(花蜜)is present.