Sleep deprivation(缺失)is an important hidden factor in lowering the achievement of school pupils, according to researchers carrying out international education tests.

    It is a particular problem in richer countries with sleep experts linking it to the use of mobile phones and computers in bedroom late at night. Sleep deprivation is such a serious problem that lessons have to be dragged down to a lower level to suit sleep-deprived learners, the study found. The international comparison, carried out by Boston College, found the United States to have the highest number of sleep-deprived students, with 73% of 9- and 10-year-olds and 80% of 13- and 14-year-olds identified by their teachers as being negatively affected.

    In literacy(读写能力) tests there were 76% of 9- and 10-year-olds lacking sleep. This was much higher than the international average of 47% of primary pupils needing more sleep and 57% among the secondary age group.

    Other countries with the most sleep-deprived youngsters were New Zealand, Saudi Arabia, Australia, England, Ireland and France. High-performing Finland is also among the most lacking in sleep. Countries with the best records for getting enough sleep include Azerbaijan, Kazakhstan, Portugal, the Czech Republic, Japan and Malta.

    The analysis was part of the huge date-gathering process for global education rankings, the Trends in International Mathematics and Science Study(TIMSS)and Progress in International Reading Literacy Study(PIRLS)

    “I think we underestimate the impact of sleep. Our data show that across countries internationally, on average, children who have more sleep achieve higher in maths, science and reading. That is exactly what our data show,” says Chad Minnich of the TIMSS and PIRLS International Study Center.

    “It's the same link for children who are lacking basic nutrition,” says Mr Minnich, based at the Lynch School of Education, Boston College. “If you are unable to concentrate, to attend mentally, you are unable to achieve at your best level, because your mind and body are in need of something more basic. Sleep is a fundamental need for all children. If teachers report such large proportions of children suffering from lack of sleep, it's having a significant impact. But worse than that, teachers are having to adjust their instruction based on those children who are suffering from a lack of sleep. The children who are suffering from a lack of sleep are driving down instruction.”

    That means that even the children who are getting enough sleep are still suffering from this sleep-related lowering.

    A Japanese telecom company has designed a robot that it says has emotions (情绪). But rather than run in fear from it, we've welcomed it into our homes: Pepper, the “emotional robots” sold out within a minute of going on sale.

    Created by Aldebaran Robotics and Japanese mobile giant SoftBaok, Pepper went on sale to the general public in Japan on June 20. It is “the first humanoid (类人的) robot designed to live with humans,” Aldebaran says on its website. Pepper costs about $ 1,600. And like all good mobile products, there's a $ 120 per month data fee, as well as an $80 per month damage insurance fee. According to a news report, Pepper can pick up on human emotions and create his own using a “multi-layer neural (神经的) network.” Pepper's touch sensors and cameras are said to influence its mood, which is displayed on the tablet-sized screen on its chest.

    Pepper will sigh when unhappy, and can go around your house recording your family's daily activity. Aldebaran says Pepper can feel “joy, surprise, anger, doubt and sadness,” but it doesn't say how strongly it can feel these emotions. What happens when Pepper is having a bad day? Will it, like many humans, become uncooperative? Will it ask for some time alone? What happens if it knows that its purpose in life is just to take part in small talk? Thankfully, Pepper is only about four feet tall, with roller balls instead of legs, so if it is angry with and even turns on its owners, you'll be safe if you can make it upstairs.

    Aldebaran says in reality, they're probably quite a few years away from artificial intelligence that could create real emotions. Aldebaran wasn't immediately able to tell when Pepper will be available out of Japan, but additional sales are scheduled for July after the first 1,000 units sell out. SoftBank currently uses the robots in its stores as greeters, and it plans to offer Pepper to other stores in the future. Hopefully “boredom” is not an emotion Pepper can feel.

    Camping wild is a wonderful way to experience the natural world and, at its best, it makes little environmental influence. But with increasing numbers of people wanting to escape into the wilderness, it is becoming more and more important to camp unobtrusively (不引人注目地) and leave no mark.

    Wild camping is not permitted in many places, particularly in crowded low—land Britain. Wherever you are, find out about organizations responsible for managing wild spaces, and contact them to find out their policy on camping and shelter building. For example, it is fine to camp wild in remote parts of Scotland, but in England you must ask the landowner's permission, except in national parks.

    Camping is about having relaxation, sleeping outdoors, experiencing bad weather, and making do without modem conveniences. A busy, fully—equipped campsite (野营地) seems to go against this, so seek out smaller, more remote places with easy access to open spaces and perhaps beaches. Better still, find a campsite with no road access; walking in makes a real adventure.

    Finding the right spot to camp is the first step to guaranteeing a good night's sleep. Choose a campsite with privacy and minimum influence on others and the environment. Try to use an area where people have obviously camped before rather than creating a new spot. When camping in woodland, avoid standing dead trees, which may fall on a windy night. Avoid animal runs and caves, and possible homes of biting insects. Make sure you have most protection on the windward side. If you make a fire, do so downwind of your shelter. Always consider what influence you might have on the natural world. Avoid damaging plants. A good campsite is found, not made—changing it should be unnecessary.

    Against the supposition that forest fires in Alaska, Canada and Siberia warm the climate, scientists have discovered that cooling may occur in areas where burnt trees allow more snow to mirror more sunlight into space.

    This finding suggests that taking steps to prevent northern forest to limit the release of greenhouse gases may warm the climate in northern regions. Usually large fires destroyed forests in these areas over the past decade. Scientists predict that with climate warming, fires may occur more frequently over next several centuries as a result of a longer fire season. Sunlight taken in by the earth tends to cause warming, while heat mirrored back into space tends to cause cooling.

    This is the first study to analyze all aspects of how northern fires influence climate. Earlier studies by other scientists have suggested that fire in northern regions speed up climate warming because greenhouse gases from burning trees and plants are released into the atmosphere and thus trap heat.

    Scientists found that right after the fire, large amounts of greenhouse gases entered the atmosphere and caused warming. Ozone (臭氧) levels increased, and ash from the fire fell on far-off sea ice, darkening the surface and causing more radiation from the sun to be taken in. The following spring, however, the land within the area of the fire was brighter than before the fire, because fewer trees covered the ground. Snow on the ground mirrored more sunlight back into space, leading to cooling.

    "We need to find out all possible ways to reduce the growth of greenhouse gases in the atmosphere." Scientists tracked the change in amount of radiation entering and leaving the climate system as a result of the fire, and found a measurement closely related to the global air temperature. Typically, fire in northern regions occurs in the same area every 80 to 150 years. Scientists, however, found that when fire occurs more frequently, more radiation is lost from the earth and cooling results. Specifically, they determined when fire returns 20 years earlier than predicated, 0.5 watts per square meter of area burned are soaked up by the earth from greenhouse gases, but 0.9 watts per square meter will be sent back into space. The net effect is cooling. Watts are used to measure the rate at which energy is gained or lost from the earth.

    Bottled water is a booming industry in New Zealand, but it's terrible for the environment —each bottle thrown away adding to the 190,000 tons of plastic New Zealanders throw into landfills each year.

    But now one company has created water storage that they hope will prove to be just as convenient as a plastic bottle—but contains no actual plastic.

    Skipping Rock Labs make Oohos, flexible membranes filled with water that are constructed using a seaweed extract—meaning they, re totally edible and biodegradable, wrapping and all.

    There aren't any known side effects from digesting the membranes, which are tasteless—though Ooho! says flavors can be added to make them more appetizing.

    The company took to crowdfunding site CrowdCube with the idea, and it has since gone viral— with more than 900 investors bagging them A£ 751,700 to develop and launch the Ooho! balls ( $ 1.35 million).

    Skipping Rock Labs create the balls by dipping ice into brown algae and calcium chloride, with the membrane taking shape around the ice—and while that may sound complicated, the company says it, s more cost-effective than producing a plastic bottle.

    A layer atop the membrane can be peeled off just before drinking, for hygiene purposes. Skipping Rock Labs are hoping their new product takes off—and that it starts to put a dent into the plastic packaging industry.

Simple ways to improve your written English

    Lots of people think it is really difficult to improve their written English. Don't worry, here are some simple steps that you can take to improve your written English.

    Increase your vocabulary(词汇)

    To express yourself clearly, you need a good active vocabulary. That's not just being able to know lots of words-it means actually being able to use them correctly. {#blank#}1{#/blank#}

    Tip: When you learn a new word, try to learn all the forms of that word.

    {#blank#}2{#/blank#}

    People often say that we learn to write best by reading. Reading in English is useful in many ways. It is a great way to get an idea of the different styles of writing and see how to use words appropriately.

    Tip: {#blank#}3{#/blank#}Learning shouldn't be boring. Read each text several times to make sure you understand how to use new words and expressions in the text.

    Improve your grammar

    Grammar is very important because it improves the quality(质量)of your writing.

    Tip: {#blank#}4{#/blank#}The first time, look for general mistakes and the second time look for mistakes with the particular grammar point you are studying at the moment.

    Just do it!

    The best way to improve your writing is to get a pen and paper and write. Be prepared to write several versions(版本)of each text. {#blank#}5{#/blank#}

A. Read widely and often.

B. Know much about your readers.

C. Always check your writing twice.

D. Remember, practice makes perfect!

E. Choose books or articles that interest you.

F. Use simple languages and shorter sentences to show your ideas.

G. Do this by learning new words with example sentences, not just word lists.