【推荐1】We've known for years that plants can see,hear,smell and communicate with chemicals.Now, reported New Scientist,they have been recorded making sounds when stressed.

In a yet-to-be-published study, Itzhak Khait and his team at Tel Aviv University, in Israel, found that tomato and tobacco plants can make ultrasonic(超声的)noises. The plants "cry out" due to lack of water,or when they are cut. It's just too high-pitched(音调高的）for humans to hear.

Microphones placed 10 centimeters away from the plants picked up sounds in the ultrasonic range of 20 to 100 kilohertz(干赫兹)。Human hearing usually ranges from 20 hertz to 20 kilohertz."These findings can change the way we think about the plant kingdom,”they wrote.

On average,"thirsty"tomato plants made 35 sounds an hour,while tobacco plants made 11. When they were cut,tomato plants made an average of 25 sounds in the following hour,and tobacco plants 15.Unstressed plants produced less than one sound per hour,on average.

Perhaps most interestingly,different types of stress led to different sounds.The researchers trained a machine-learning model to separate the plants' sounds from those of the wind,rain and other noises of the greenhouse.In most cases,it correctly recognized whether the stress was caused by dryness or a cut.Water-hungry tobacco appears to make louder sounds than cut tobacco,for example.Although Khait and his colleagues only looked at tomato and tobacco plants,they think other plants also make sounds when stressed.

If farmers could hear these sounds,said the team,they could give water to the plants that need   it most.As climate change causes more droughts,they said this would be important information for farmers. "The sounds that drought-stressed plants make could be used in precision(精准) agriculture, "said Anne Visscher at the Royal Botanic Gardens,Kew,in the UK.

Khait's report also suggests that insects can hear the sounds up to 5 meters away and respond. For example,a moth(蛾子）may decide not to lay eggs on a water-stressed plant.Edward Farmer. at the University of Lausanne,Switzerland,is doubtful.He said that the idea of moths listening to plants is"a little too speculative”。

If plants are screaming(尖叫）for fear of their survival,maybe we should be glad we can't hear them.

【推荐1】If you live in a town or city on the edge of a desert or coastline where sand dunes form, you might understand the threat they can have. It’s, sometimes, a piece of cake for them to cover roads, buildings, farms and other man-made developments with their unpredictable movements. Thus, figuring out how they move is important for preventing some natural disasters.

Now scientists have discovered that dunes have been secretly moving in ways we never knew before. There are different explanations on dune interaction, however, Karol Bacik, first author on the new dune study, and his colleagues have found a new one for dune movement. The researchers employed high-speed cameras to observe how dunes separated by distance can act as if they’re connected.

It turns out, currents flowing over sand dunes can carry “information” to other dunes downstream in the form of swirls(旋涡). For instance, as wind or water flows over the top of a dune, it slightly moves. This can generate “swirls” on the back of a downstream dune and push it in a direction opposite the movement of the front dune.

It’s the first time that researchers were able to provide causal explanations for some of these strange, previously unpredictable movements. The team also hopes to get out of the laboratory and into the real world, to see if their models can be applied to dune movements in complex natural systems. They plan to use satellite images over large deserts to track groups of dunes over long periods.

Perhaps they can start to alter the dune marching orders in the near future. Imagine being able to tell a dune field exactly how you want it to move. That’s the idea that this research might one day make possible.

【推荐3】Scientists today are making greater effort to study ocean currents (洋流). Most do it using satellites and other high­tech equipment. However, ocean expert Curtis Ebbesmeyer does it in a special way — by studying movements of random floating garbage. A scientist with many years’ experience, he started this type of research in the early 1990s when he heard about hundreds of athletic shoes washing up on the shores of the northwest coast of the United States. There were so many shoes that people were setting up swap meets to try and match left and right shoes to sell or wear.

Ebbesmeyer found out in his researches that the shoes — about 60,000 in total — fell into the ocean in a shipping accident. He phoned the shoe company and asked if they wanted the shoes back. As expected, the company told him that they didn’t. Ebbesmeyer realized this could be a great experiment. If he learned when and where the shoes went into the water and tracked where they landed, he could learn a lot about the patterns of ocean currents.

The Pacific Northwest is one of the world’s best areas for beachcombing (海滩搜寻) because winds and currents join here, and as a result, there is a group of serious beachcombers in the area. Ebbesmeyer got to know a lot of them and asked for their help in collecting information about where the shoes landed. In a year he collected reliable information on 1,600 shoes. With this data, he and a colleague were able to test and improve a computer program designed to model ocean currents, and publish the findings of their study.

As the result of his work, Ebbesmeyer has become known as the scientist to call with questions about any unusual objects found floating in the ocean. He has even started an association of beachcombers and ocean experts, with 500 subscribers from West Africa to New Zealand. They have recorded all lost objects ranging from potatoes to golf gloves.

【推荐2】In the more and more competitive service industry, it is no longer enough to promise customer satisfaction. Today, customer “delight” is what companies are trying to achieve in order to keep and increase market share.

It is accepted in the marketing industry, and confirmed by a number of researches, that customers receiving good service will promote business by telling up to 12 other people; those treated badly will tell their tales of woe to up to 20 people. Interestingly, 80 percent of people who feel their complaints are handled fairly will stay loyal.

New lineages for customer care have come when people can obtain goods and services through telephone call centers and the Internet. For example, many companies now have to invest (投资) a lot of money in information technology and staff training in order to cope with the “phone rage (愤怒)” — caused by delays in answering calls ,being cut off in mid-conversation or left waiting for long periods.

“Many people do not like talking to machines,” says Dr. Storey Senior Lecturer in Marketing at City University Business School, “Banks, for example, encourage staff at call centers to use customer data to establish instant and good relationship with them. The aim is to make the customer feel they know you and that you can trust — the sort of comfortable feelings people have during face-to-face chats with their local branch manager.”

Recommended ways of creating customer delight include: under-promising and over-delivering (saying that a repair will be come out within five hours, but getting it done within two ); replacing a faulty product immediately: throwing in a gift voucher (购物礼券) as an unexpected “thank you” to regular customers; and always returning calls, even when they are complaints.

Aiming for customer delight is all very well, but if services do not reach the high level promised, disappointment or worse will be the result. This can be eased by offering an apology and an explanation of why the service did not meet usual standards with empathy (for example, “I know how you must feel”), and possible solutions (replacement, compensation or whatever suggests best meets the case).

Airlines face some of the toughest challenges over customer care. Fierce competition has convinced them that delighting passengers is an important marketing tool, while there is great potential for customer anger over delays caused by weather, unclaimed luggage and technical problems.

For British Airways staff, a winning telephone style is considered vital in handling the large volume of calls about bookings and flight times. They are trained to answer quickly, with their name, job title and a “we are here to help” attitude. The company has invested heavily in information technology to make sure that information is available instantly on screen.

British Airways also says its customer care policies are applied within the company and staff are taught to regard each other as customers requiring the highest standards of service.

Customer care is obviously here to stay and it would be a foolish company that used slogans such as “we do as we please”. On the other hand, the more customers are promised, the greater the risk of disappointment.

【推荐3】We usually hear the term addiction used when talking about drugs or alcohol. But researchers are finding that certain foods can trigger(引发)the same feelings as drugs. It all comes down to what’s happening in the brain. When we feel a happy rush, it’s due to a flood of the feel-good chemical in our brain. Drugs and alcohol can cause a similar high. So, it turns out, can some popular snack foods.

“We’re designed to find carbohydrates(碳水化合物)and fats reinforcing,” says Ashley Gearhardt. She’s a psychologist. “Evolving(进化)such tastes helped our ancestors overcome famine when we couldn’t find enough to eat and make sure we survive.” she explains. That critical role shaped the brain’s reward system, making us hard-wired to enjoy carbohydrates and fatty foods.

The problem isn’t with all foods containing carbohydrates and fats. Fruit is full of sugar. Oats and other whole grains have lots of carbohydrates. Nuts and meat have fat. But such unprocessed foods eaten in a form that’s similar to how they grew-also contain other nutrients, such as fiber, that slow digestion. That limits how quickly our bodies can absorb the nutrients. Cookies, candy, soda, fries and other highly processed foods lack those additional nutrients. Such foods contain ingredients that have been highly changed from their natural state. They’re full of easy-to-absorb carbohydrates and added fats. What’s more, they often contain ingredients that don’t naturally occur together. “Sugar and fat don’t come together in nature,” Gearhardt says. But highly processed foods often “have unnaturally high levels of both carbohydrates and fat.” When we cat these foods, we get a quick “hit” of carbohydrates and fats that give the brain a boost That makes us want to eat them again and again.

“Pay attention to what you eat,” Gearhardt says. “It’s best to get plenty of nutritious foods for your mind and body. That doesn’t mean you can`t have a donut or pizza now and then. Just be sure you’re aware of what you’re eating.”

【推荐1】Student loans are based on a simple idea: that a graduate’s future flow of earnings will more than cover the costs of doing a degree. But with unemployment rates in parts of the rich world at post-war highs, that may no longer hold true for many people. The consequences will be felt by everybody.

All over the world student indebtedness is causing problems. In Britain, rising university fees mean that student debt is likely to treble (变成三倍) to £70 billion. But, partly because higher education there is so expensive, the scale of the problem is far greater in America. When the next official estimates of outstanding student debt there are published, it is expected to be close to $1 trillion.

Student-loan systems in America and elsewhere are often badly designed for an extended period of high unemployment. In contrast to the housing crash, the risk from student debt is not of a sudden explosion in losses but of gradual financial suffocation (窒息). The pressure needs to be eased.

One option is to change the bankruptcy laws. In America, Britain and elsewhere, these treat student debt as a special case: unlike other forms of debt, it cannot be wiped out. If student debt is not to bind existing graduates and put off future ones, the rules could be changed so that it is dischargeable (可解除的) in bankruptcy. Yet some worry that graduates would rush to declare bankruptcy, handing losses to taxpayers.

So a second option is preferable. Many countries, America included, have designed student debt primarily as a mortgage (抵押)-like obligation: it is repaid to a fixed schedule. Other places, like Britain and Australia, make student-loan repayments income- based so that the prospect of taking on debt is more acceptable to people from poorer backgrounds. That approach makes sense, especially when jobs are scarce.

Both changes would lead to a repricing of student debt. That would be a bad thing for taxpayers, but a good thing overall. Just as borrowers need to understand the risks they are exposing themselves to, voters need to understand the duties that governments are taking on when they subsidize (资助) students.

【推荐2】A book is made of wood. But it is not a tree. The dead cells have been repurposed to serve another need.

Now a team of scientists has repurposed living cells—scraped(刮落)from frog embryos—and assembled them into entirely new life forms. These millimeter-wide “xenobots” can move toward a target, perhaps pick up a payload(like a medicine that needs to be carried to a specific place inside a patient)—and heal themselves after being cut.

“These are novel living machines,” says Joshua Bongard, a computer scientist and robotics expert at the University of Vermont who co-led the new research. “They're neither a traditional robot nor a known species of animal. It's a new class of artifact：a living, programmable organism.” “We can imagine many useful applications of these living robots that other machines can't do,” says co-leader Michael Levin, “like searching out nasty compounds or radioactive contamination(污染物), gathering microplastic in the oceans, traveling in arteries(动脉)to scrape out plaque.”

People have been manipulating(操纵)organisms for human benefit since at least the dawn of agriculture, genetic editing is becoming widespread, and a few artificial organisms have been manually assembled in the past few years—copying the body forms of known animals. But this research, for the first time ever, “designs completely biological machines from the ground up," the team writes in their new study.

Many people worry about the implications of rapid technological change and complex biological manipulations. "That fear is not unreasonable,” Levin says. "When we start to deal with complex systems that we don't understand, we're going to get unintended consequences.” “If humanity is going to survive into the future, we need to better understand how complex properties, somehow, emerge from simple rules,” says Levin. Much of science is focused on "controlling the low-level rules. We also need to understand the high-level rules." In other words, “this study is a direct contribution to getting a handle on what people are afraid of, which is unintended consequences,” Levin says.

【推荐3】Solving great space mystery

Monkey King, the hero in the classic Chinese novel Journey to the West, is making headlines again. On Nov 30, China’s Dark Matter Particle Explorer(DAMPE, 暗物质粒子探测卫星), which is named after Monkey King’s Chinese name Wukong, found mysterious signals in the universe that may help scientists learn more about dark matter, according to Xinhua News Agency.

“This is the first time scientists have found such detailed and precise signals, ” Chang Jin, vice director of the Purple Mountain Observatory of the Chinese Academy of Sciences (中国紫金山天文台), told Xinhua.

Dark matter is a type of hypothetical(假设的)matter in the universe. Scientists believe that it influences the movement of galaxies. However, no one has ever directly observed it.

Swiss astronomer Fritz Zwicky first used the term “dark matter” in 1933, when he spotted something very unusual. Some galaxies that Zwicky saw were spinning so fast that they should have scattered into all comers of the universe, but they didn’t. He realized there must have been something else there that had a strong enough gravitational pull to hold everything together. He called it“dark matter”.

In one sense, dark matter is like the wind：we can’t see it, but we know it’s there.

Finding out more about dark matter could help us understand how the universe began, but being able to do so isn’t easy. Scientists believe that when two dark matter particles crash together, they form new particles and produce high amounts of energy and heat. This is why explorers like Wukong are sent to find such particles.

Indeed, “Wu” means “understanding” and “kong” means “void(空的). ” The nickname symbolizes the main goal of DAMPE’s mission, which is to understand dark matter better.

Since its launch in 2015, DAMPE has already recorded 3. 5 billion high-energy particles, reported Newsweek. And according to Science, the satellite has a lifespan of five years, which means it still has three more years to “understand the void”. “DAMPE has opened a new window tor observing the high-energy universe, unveiling new physical phenomena beyond our current understanding, ” Chang told Xinhua.