C

Plastic-Eating Worms

    Humans produce more than 300 million tons of plastic every year. Almost half of that winds up in landfills(垃圾填埋场), and up to 12 million tons pollute the oceans. So far there is no effective way to get rid of it, but a new study suggests an answer may lie in the stomachs of some hungry worms.

    Researchers in Spain and England recently found that the worms of the greater wax moth can break down polyethylene, which accounts for 40% of plastics. The team left 100 wax worms on a commercial polyethylene shopping bag for 12 hours, and the worms consumed and broke down about 92 milligrams, or almost 3% of it. To confirm that the worms' chewing alone was not responsible for the polyethylene breakdown, the researchers made some worms into paste(糊状物) and applied it to plastic films. 14 hours later the films had lost 13% of their mass — apparently broken down by enzymes (酶) from the worms' stomachs. Their findings were published in Current Biology in 2017.

    Federica Bertocchini, co-author of the study, says the worms' ability to break down their everyday food — beeswax — also allows them to break down plastic. ＂Wax is a complex mixture, but the basic bond in polyethylene, the carbon-carbon bond, is there as well, ＂she explains, ＂The wax worm evolved a method or system to break this bond. ＂

    Jennifer DeBruyn, a microbiologist at the University of Tennessee, who was not involved in the study, says it is not surprising that such worms can break down polyethylene. But compared with previous studies, she finds the speed of breaking down in this one exciting. The next step, DeBruyn says, will be to identify the cause of the breakdown. Is it an enzyme produced by the worm itself or by its gut microbes(肠道微生物)?

    Bertocchini agrees and hopes her team's findings might one day help employ the enzyme to break down plastics in landfills. But she expects using the chemical in some kind of industrial process — not simply ＂millions of worms thrown on top of the plastic.＂

    An American company has built a new drone（无人机）that could improve the speed of deliveries（送交的货）.

    The drone is very different from other unmanned aircraft.It is made almost completely out of cardboard and has no motor.It can be packed with materials and sealed up with tape.

    Because the drones do not have a motor,they are designed to be dropped from airplanes.Hundreds of drones could be sent out at once.Then they could be automatically guided to where they are supposed to go.The company says these drones could then complete deliveries to different places over an area covering hundreds of kilometers. The drones look bigger than the paper airplanes we used to make as kids.But this light flyer is not a toy.It is aerodynamically designed and equipped with a small computer,a battery and sensors to guide it to the ground.

    The drones are being developed by Otherlab—a technology research company in San Francisco,California.It calls the drone a "Sky Machine."

    The company says it can travel about 150 kilometers at speeds up to 88 kilometers an hour.Now,it can carry materials weighing up to one kilogram,but future models are expected to carry larger loads.

    One of the drone's main advantages is that it does not have a heavy motor or large battery.This allows more room for materials and makes the drone cost less to build and operate.

    The Otherlab development team has called its invention the "Ikea of drones".This is because it is packaged similarly to products from the Swedish furniture maker Ikea.The drone arrives as flat pieces of pre-cut cardboard that can be quickly and easily put together.

    The technology that guides the drone can make it land within 10 meters of its target,according to Otherlab. Unlike other drones,even a crash landing is acceptable.The company says the drones can also be reused.

    Once the drone completes its delivery,it can be thrown away and the cardboard material will likely break down within a few months.

    The company has received money from the U.S. Department of Defense to carry out research on the drones.The money came from the Defense Advanced Research Projects Agency.The agency is attempting to find the best delivery vehicles that can disappear after their missions are complete.The U.S. military has a need for delivery drones.But it wants to simplify and lower the cost of using them.Otherlab's Sky Machines are an attempt to fill that need.

    Military drones can also be stolen and studied by others if found after use.Before they can truly disappear,the electronic materials inside must also somehow disappear.Researchers are still working on ways to get the technology itself to self-destruct.

    I am sure we've all come across inspiring quotes（引言）that made us nod in agreement or made us think, "Wow, that's good quotes". But we end up going back to procrastinating（拖延）on whatever it was we were procrastinating on. So is it worthwhile to read these inspirational quotes? Well, that depends.

    Quotes, books, articles, audio programs… all of these things are just tools and they're only effective when you use them. I don't know about you but most quotes I read don't do anything for me. However, every now and then, I will come across one that will positively affect me in some way such as reminding me to be grateful, getting me to work out extra hard at the gym without being pressed by my wife, or never give up when things get tough.

      From my experience, reading quotes is more effective when you're actually trying to motivate yourself rather than just reading them for the sake of reading them. The second you feel the urge to take action, you'd better immediately get up off your chair and take action.

    These quotes aren't for everyone. If you have read tons of them and have never been motivated or had a positive change in the way you look at life or how you treat others, or these quotes don't help you to insist on doing something when you feel like giving up on it, then it's probably not worthwhile to read more of them. If you have done something a bunch of times and it's not giving you the results you want, don't keep doing it. Try something else.

    Now if you've found some value in reading these quotes in the past, continue to make them more effective by letting them guide your life.

    What do you do for fun in your spare time? Do you like reading? Do you often go to a book store? There is a store that is so different from others.

    The World's Smallest Bookstore, whose official name is just these three words, sits quietly about 100 miles northeast of Toronto.

    The bookstore is about 10 feet by 10 feet, so it is easy to imagine how tiny it really is. The bookstore is open 24 hours a day. Inside the bookstore are various books, especially literary books and classic authors' works. So if you are looking for something less popular, you may get a bit disappointed there.

    Another special feature of this bookstore is that each book only costs three dollars. All the expenses are paid on the honor system, which means buyers should make a note of what they've bought and leave their money by themselves. So the tools of the trade in this bookstore are quite simple: pens, papers, light bulbs and a label-maker.

    In order to catch passers-by's attention, the billboards (广告牌) of the bookstore are several times bigger than the store itself. With these large eye-catchers, many people are willing to stop by and have a visit.

    The 2019 Beijing Horticultural Expo, the largest of its kind, has chosen the theme "Live Green, Live Better". The expo, opened on April 29 in Yanqing District of Beijing, is scheduled to last for 162 days until October 7.

    Tickets available

    *Standard day ticket

    *Designated day ticket

    *Discounted ticket

    *Group ticket

    Designated days

    *Labor Day holiday (May 1-4)

    *Dragon Boat Festival holiday (June 7-9)

    *Mid-Autumn Festival holiday (Sept 13-15)

    *National Day holiday (Oct 1-7)

    Tickets prices

    *Standard day ticket: 120 yuan

    *Ordinary designated day ticket: 160 yuan

    *Discounted standard day ticket: 80 yuan

    *Discounted designated day ticket: 120 yuan

    Tickets are free for children under the age of six or shorter than 130 centimeters. Discounted tickets are available for those with disabilities, seniors (people aged at 60 or above), children, students and PLA soldiers.

    Where to buy

    Visitors can buy or book tickets from two online agents, seven travel agencies, or three event channels—the event WeChat account, the event app or Onsite ticket kiosks.

Opening hours

Requirements

    Buying tickets for Expo 2019 Beijing requires real-name registration, and all visitors are required to input information from their ID cards (or valid passports, mainland travel permits for Hong Kong and Macao residents, and mainland travel permits for Taiwan residents) to buy or book tickets online.

    You probably know who Marie Curie was, but you may not have heard of Rachel Carson. Of the outstanding ladies listed below, who do you think was the most important woman of the past 100 years?

    Jane Addams (1860-1935)

    Anyone who has ever been helped by a social worker has Jane Addams to thank. Addams helped the poor and worked for peace. She encouraged a sense of community(社区)by creating shelters and promoting education and services for people in need. In 1931, Addams became the first American woman to win the Nobel Peace Prize.

    Rachel Carson (1907-1964)

    If it weren't for Rachel Carson, the environmental movement might not exist today. Her popular 1962 book Silent Spring raised awareness(意识) of the dangers of pollution and the harmful effects of chemicals on humans and on the world's lakes and oceans.

    Sandra Day O'Connor (1930-present)

    When Sandra Day O'Connor finished third in her class at Stanford Law School, in 1952, she could not find work at a law firm because she was a woman. She became an Arizona state senator(参议员) and in 1981, the first woman to join the U. S. Supreme Court(最高法院). O'Connor gave the deciding vote in many important cases during her 24 years on the top court.

    Rosa Parks(1913-2005)

    On December 1,1955, in Montgomery, Alabama, Rasa Parks would not give up her seat on a bus to a white passenger. Her simple act landed Parks in prison. But it also set off the Montgomery bus boycott(抵制). It lasted for more than a year, and kicked off the civil-rights movement. "The only tired I was, was tired of giving in," said Parks.