To prevent the deserts coming near, China has planted billions of trees—to replace destroyed forests and as barriers against the sand. This isn't a cure, though, say experts, as thirsty trees can make the problem worse by taking in groundwater.

    “Planting tress is one way, but it isn't that simple. It doesn't solve the basic issue of water resources,” says Wu Bo, a professor. “We need to calculate how much water the trees will absorb, or else it could have a negative effect.”

    Villagers in Zhengxin have taken on this challenge, with limited success. When the irrigation channels began to run dry, Lu Xianglin switched from wheat to cotton on his land. He also planted trees to protect his fields from sandstorms. He says he still gets good yields（产量） using flood irrigation and earns a good income for his family.

    Other farmers haven't stuck it out（坚持到底）: about one in three have left Zhengxin in the past 10 years after their wheat crops died. Young people who can find jobs in the towns rarely return.

    Last week, Mr Lu joined the other men in his village on a government-arranged trip to see the land that has been set aside for their relocation, nearly 40 miles to the south. The next day, he was back, shaking his head at the plan. The idea of uprooting his family troubles him, as does the idea of giving up the land that fed his forefathers. He prefers to stay and keep up the fight.

    “With enough water, this problem can be solved,” Lu says. “We can plant trees and grass, and they will grow bigger. That will stop the desert.”

    Experts say that farmers could switch to drip irrigation （滴灌）to lessen their water intake for growing crops. Elsewhere in the region, farmers have built brick greenhouses as part of a plan to grow vegetables using less water. Roadside signs urge farmers to “Save Water, Protect the Environment”.

    Coral reefs are,in fact,a necessary part of our ecosystem and provide opportunities for human beings to gain a better understanding of the ocean.Unfortunately,they're also disappearing faster than ever.

    According to a warning by the US National Oceanic and Atmospheric Administration(NOAA) on Oct.8,the world is in its third recorded global coral bleaching（白化）since 1998 and 2010.This means no place with coral has been spared,as coral reefs are coming into contact with increasingly warm seas,which is leading to them dying off in large numbers.

    Coral bleaching is like human cancer.It happens when corals are under stress from changes in light,nutrients,or temperature.This causes the coral to drive away the symbiotic algae（共生藻类）,living within their tissues（组织）, which play an important role in providing food for coral while making it colorful.Without the algae,coral reefs become pale and weak.In some cases they are not able to recover and eventually die off.

    The current coral bleaching event started back in late 2014 and continued into this year with no signs of stopping.The BBC reports that 35% of coral reefs in the world will likely be affected,and an estimated 4,633 square miles (about 120,000 square kilometers) of coral reefs could die.

    The loss of coral reefs is no small matter.Although they only take up 0.1% of the ocean floor,coral is home to about 25% of marine life.This isn't just a problem for divers and fish,as Eakin pointed out.Coral reefs are important globally,he added,as they protect shorelines,produce money in tourism,and help provide food for 500 million people worldwide.So people cannot overlook the environmental,economic and social effects of the loss.

    The NOAA warning about coral bleaching came just about two months before a global climate summit（峰会）in Paris,where hundreds of world leaders will attempt to work out a plan to fight climate change.

    Oceans will be a key subject during the summit,and Eakin says there's an "absolutely urgent need" for action.

    Milton Hershey was born near the small village of Derry Church, Pennsylvania, in 1857. He only attended school through the fourth grade; at that point, he was apprenticed(做学徒) to a printer in a nearby town. After a while, he left the printing business and was apprenticed to a Lancaster, Pennsylvania candy maker. And at the age of eighteen, he opened his own candy store in Philadelphia. In spite of his talents as a candy maker, the shop failed after six years.

    After the failure of his Philadelphia store, Milton headed for Denver, where he learned the art of making caramels(焦糖). Then in Denver, Milton once again attempted to open his own candy-making businesses, in Chicago, New Orleans, and New York City. Finally, in 1886, he went to Lancaster, Pennsylvania, where he raised the money necessary to try again. This company— the Lancaster Caramel Company—established Milton's reputation as a master candy maker.

    In 1893, Milton attended the Chicago International Exposition, where he saw a display of German chocolate-making implements. Fascinated by the equipment, he purchased it for his Lancaster candy factory and began producing chocolate, which he used for coating his caramels. By the next year, production had grown to include cocoa, sweet chocolate, and baking chocolate. The Hershey Chocolate company was born in 1894 as a subsidiary(子公司) of the Lancaster Caramel Company. Six years later, Milton sold the caramel company, but reserved the rights, and the equipment, to make chocolate. He believed that a large market of chocolate consumers was waiting for someone to produce reasonably priced candy. He was right.

    Milton Hershey returned to the village where he had been born, in the heart of dairy country, and opened his chocolate manufacturing plant. With access to all the fresh milk he needed, he began producing the finest milk chocolate. The plant that opened in a small Pennsylvania village in 1905 is today the largest chocolate factory in the world. The sweets created at this facility are favorites around the world.

    The area where the factory is located is now known as Hershey, Pennsylvania. Within the first decades of its existence, the town of Hershey thrived, as did the chocolate business. A bank, a school, churches, a department store, even a park and a trolley system all appeared in short order; the town soon even had a zoo. Today, a visit to the area reveals the Hershey Medical Center, Milton Hershey School, and Hershey's Chocolate World—a theme park where visitors are greeted by a giant Reeses Peanut Butter Cup. All of these things— and a huge number of happy chocolate lovers—were made possible because a caramel maker visited the Chicago Exposition of 1893!

    Teenagers around the world can be happy with the news that the brain will ignore parents' order when they use their smart phones. A new scientific study from the University College London has shown that humans may temporarily go deaf when they're focusing on something visual (视觉的) at the same time.

    The researchers played the normal-volume sounds in the background. And 13 volunteers experienced inattentional deafness as their visual tasks became increasingly difficult. "We found that when volunteers were performing the difficult visual task, they were unable to hear sounds that they would normally hear," Maria Chait said in a statement. "The brain scans showed that people didn't filter out the sounds on purpose. They were not actually hearing them in the first place."

    The findings, published in the Journal of Neuroscience, suggest that the centre of sights and the center of sounds share limited resources. Inattentional deafness is a common everyday experience and the study explains why, according to UCL Institute of Cognitive Neuroscience Professor Nili Lavie.

    If you try to talk to someone focusing on a book, game, or television program and don't receive a response, they aren't necessarily ignoring you. They simply might not hear you at all. This could also explain why you might not hear your bus or train stop being announced if you're lost in your phone, book or newspaper. However, some loud sounds will still be able to break through.

    Some situations could become possibly dangerous when the quieter ones go unheard. As you can imagine, in the operating room, when a doctor concentrates on his work, he might not hear the equipment beeping. It also applies to drivers who center on complex directions. Fortunately, experts have given us some useful tips on preventing such situations.

    We work with Cambridge County Council's Participation Team to create opportunities for young people to visit the University and learn more about it. The following events are scheduled for the 2019/2020 academic year.

    Superstar workshops

    12 engaging workshops are planned for young people aged 7 to 11. These half-day visits will be held throughout the year, at times when young people are not at school. If participants complete 8 of the 12 workshops, they will be awarded the nationally recognized Superstar Crest Award.

Please note, workshops will only run if we have a sufficient number of attendees (usually around 3+ participants).

    Explore University Days

    Explore University Days are for young people aged 12-15. Participants visit the University for two days and engage with a range of university-related workshops, and other fun activities.

Previous participants have engaged with the following:

    Visited the Sports Centre

    Took part in a Neuroscience workshop

    Enjoyed a two-course meal at a University College

    Dates will be confirmed in early December 2019, and a schedule for event will follow in the New Year.

    Events for post-16 students

    If you are studying for your post-16 qualifications and are considering applying for Cambridge or would like to find out more about a specific subject, the following events might be for you:

    University and College Open Days

    Subject Master classes

    Cambridge Science Festival

    A shark moving around the coastline is normally a worrying sight，but this waterborne drone (无人机) threatens floating rubbish instead of people.

    Developed by Dutch company RanMarine, the WasteShark takes nature as its inspiration with its whale shark-like mouth. Responsible for collecting waste, the drone will begin operations in Dubai Marina in November after a year of trials with local partner Ecocoast.

    According to RanMarine, the WasteShark is available in both autonomous and remote-controlled models. Measuring just over five feet by three-and-a-half feet (1.5 meters by 1.1 meter), it can carry up to 352 pounds of rubbish (159.6 kg) and has an operational battery life of 16 hours.

    By 2016 there were approximately 150 million tons of plastic in the world's oceans. One paper from December 2014 estimated that over a quarter of a million tons of ocean plastic pollution was afloat.

    "WasteShark also has the abilities to gather air and water quality data, remove chemicals out of the water such as oil, and heavy metals, and scan the seabed to read its depth and outlines," said Oliver Cunningham, one of the co-founders of RanMarine. "Fitted with a collision-avoidance system, the drone uses laser imaging detection and ranging technology to detect an object in its path and stop or back up if the object approaches."

    "Our drones are designed to move through a water system, whether it's around the perimeter (周边) or through the city itself. The drones are that last line of defense between the city and the open ocean," added Cunningham. "WasteSharks are operating in Dubai, South Africa and the Netherlands and cost $ 17, 000 for the remote-controlled model and just under $ 23, 000 for the autonomous model."

    Dubai-based operator Ecocoast has two WasteShark drones. Co-founder Dana Liparts says they will clean waterfronts for clients including hotels and environmental authorities and that Ecocoast' intention is to have the collected rubbish recycled or upcycled. However, Liparts argues that cleaning waterways doesn't have a one-size-fits-all solution and requires a combination of new technology, preventative measures and changing people's attitudes towards littering.