Can a fish be depressed? This question has been on my head ever since I spent a night in a hotel across from a sad-looking fish. His name was Bruce Lee.
The pleasant woman at the front desk assured me that he was well taken care of. Was I incorrectly assuming his laziness was a sign of being upset?
When I sought answers from scientists, I assumed that they would find the question ridiculous. But they did not. New research has been totally shifting the way that scientists think about fish cognition (认知)，building a case that pet and owner are not nearly as different as many assume. The neurochemistry (神经化学）is so similar that it’s scary, said Julian Pittman，a professor. We tend to think of them as simple living things, but there is a lot we don't give fish credit for.
Dr. Pittman likes working with fish, in part, because they are so obvious about their depression. A zebrafish gets dropped in a new tank. If after five minutes it is hanging out in the lower half, it’s depressed. If it’s swimming up top, then it’s not.
Is depression the right word? There's the obvious issue that we cannot ask animals how they feel, says Dr. Diego A. Pizzagali . Neither fish nor rats can catch the entire range of depression as we know it.
There is a heated debate about whether anxious or depressed is a more appropriate term. But what has convinced Dr. Pittman, and others, over the past ten years is watching the way the zebrafish lose interest in just about everything: food, toys, exploration, just like clinically depressed people who are withdrawn. The same is true of fish.
One of the things we're finding is that fish are naturally curious and seek novel things out, said Dr. Braithwaite. In other words, your goldfish is probably bored. To help get rid of depression, she urges introducing new objects to the tank or switching up the location of items.
1. What is Paragraph 3 mainly about?| A．Fish are considered simple living things. |
| B．Pet and owner are always assumed the same. |
| C．Scientists have learnt a lot about fish cognition. |
| D．Fish and human beings have something in common. |
| A．Quiet and shy. |
| B．Happy and excited. |
| C．Interested and careful. |
| D．Disappointed and surprised. |
| A．They need oxygen from the air. |
| B．They are not born to be curious. |
| C．They lack new things to explore. |
| D．They can’t locate the positions of items. |
| A．Fish Depression Is not a Joke. |
| B．Fish Can Be a Boring Pet. |
| C．Fish Need Better Care More. |
| D．Fish Cognition Does not Exist. |
相似题推荐
【推荐1】Armed with surprisingly powerful forelegs, the brown bear, also known as grizzly, is the fastest of the eight bear species, reaching speeds of up to 35 mph. The grizzly is only slightly faster than the world’s most common bear species, the American black bear.
Of course, a bear would be able to achieve such a speed only at the top of its athletic ability—not fresh out of hibernation (冬眠), having lost 15% to 30% of its body weight — and only on certain soft, flat surfaces into which their long claws (爪子) can run easily.
In any case, bears are surprisingly fast considering their huge bodies. Discover the characters that make their quickness possible, and what to do (besides run) if you encounter one in the wild.
Even the fastest known human on Earth, Usain Bolt, could not run faster than a determined black or grizzly bear at its top speed. The famous Jamaican short-distance runner achieved the fastest recorded human foot speed ever during a 2009 race in Berlin. He was clocked going an unbelievable 27.8 mph, about 4 mph faster than his average (平均) speed and more than 10 mph faster than the average human runner. Still, that’s 7 mph slower than the supposed top speed of a grizzly and just over 2 mph short of a black bear’s.
At his record speed, Bolt may be able to run faster than a slow polar bear, which tops out at 24 mph, or a panda, which can reportedly go 20 mph. A bear, however, can keep up speeds of 25 to 28 miles per hour for 2 miles. The average human, running at a comparatively slow 15 mph, would simply not stand a chance. The good news is that bears, and most wildlife, would usually rather avoid humans than run after them. They generally only attack to protect their food, young, and space.
1. What does the text mainly tell about the bear?| A．Its types. | B．Its speed. | C．Its power. | D．Its weight. |
| A．Watch over. | B．Pick out. | C．Run after. | D．Come across. |
| A．To make readers better understand the bears' speed. |
| B．To describe the fastest man in the world. |
| C．To warn us of the great danger from the bears. |
| D．To introduce a new topic to discuss. |
| A．A bear. | B．A panda. | C．A polar bear. | D．An average human. |
【推荐2】Daphne Soares, a biologist, made an amazing discovery about alligators (短吻鳄). The investigation of the sensory dots of alligators began when she was at university. Now she holds a research position at the University of Maryland.
The first time Daphne Soares got really close to an alligator was when she was helping to hold down an eight-foot alligator. When she got close to the alligator, she noticed that its face was covered with little black spots.
She started her study of the black dots when she went to the library. When she read the books and the scientific journals, she learned that people had noticed the dots. People thought that the dots were some kind of sense organ. However, no one really knew what the dots were for.
It was a complete accident when she found out what the dots were used for. She placed electrodes (电极) on nerves coming from some of the sensory dots. When the nerves were stimulated, they created a tiny electric current. Just then she heard a small sound over a audio speaker. She tried to see if the dots acted like eyes and temperature sensors, but nothing worked. One day she accidentally dropped a tool into an alligator’s tank. When she put her hand in the tank to get the tool out, she made small ripples (涟漪) in the water. When the ripples reached the alligator’s face, she heard a noise over the speaker. She then realized that the dots must be sensitive to the changes in pressure when they were hit by ripples of water.
After that, she is now studying blind cavefish. She is trying to learn whether they are blind from birth or lose their sight as they grow up.
1. What was Daphne Soares doing when she noticed the black dots?| A．Studying the sense organ. |
| B．Helping to keep a hold of an alligator. |
| C．Observing an alligator in a pond. |
| D．Reading scientific journal in the library. |
| A．She collected data online. |
| B．She did some field observations. |
| C．She sought help from professionals. |
| D．She did some scientific experiments. |
| A．The sense of feeling. | B．The sense of sight. |
| C．The sense of taste. | D．The sense of hearing. |
| A．A Born Biologist | B．The Types of Alligators |
| C．A Discovery About Alligators | D．Daphne Soares’ Stories |
【推荐3】Most dog owners are convinced that their four-legged friends know exactly what they mean when they use certain words like “sit”, “stay”, or “treat”. However, scientists have always wondered whether dogs really understand human speech or if they rely on other clues to arrive at the meaning.
To find the answer, scientists at Atlanta’s Emory University did a study. They began by asking the owners of twelve dogs of various breeds to train their pets to identify two toys-a stuffed animal and a ball. Once the dogs had mastered the task, they took turns inside a functional magnetic resonance imaging(fMRI)scanner(功能性磁共振成像扫描仪). The owners then tested their dogs’ language skills by first calling out the names of the toys they had been trained to recognize and then saying meaningless words such as “bobbu” and “bodmick” while holding up random objects the dogs hadn’t seen before.
The fMRI scans revealed that the regions of the dogs’ brains responsible for auditory(听觉的)processing showed different brain patterns when they heard words they were familiar with, compared with the ones they had never heard before. While not enough to prove that the dogs were picturing their toys when they heard the word, it did indicate some sort of recognition. The scientists believe this is an important step forward in understanding how dogs process language.
An even more interesting thing was that the dogs’ brains showed a higher level of neural activity at the sound of unknown words. This is the exact opposite of what happens in human brains. The scientists guess the dogs may become excited at the new words to try to understand them in the hope of delighting their owners.
However, though your pet may understand human speech, the scientists recommend using visual and scent cues(视觉和气味的提示)for training. “When people want to teach their dogs a trick, they often use a verbal command because that’s what we humans prefer,” Prichard, a Ph.D.at Emory’s Department of Psychology and the study’s first author, says. “From the dog’s perspective, however, a visual command might be more effective, helping the dog learn the trick faster.”
1. What did scientists do for the study?| A．They trained the dogs. | B．They turned to dog owners. |
| C．They referred to previous research. | D．They did various experiments in the lab. |
| A．Dogs can understand words. | B．Dogs have their own language. |
| C．Dogs do well in recognizing things. | D．Dogs have the ability to recall images. |
| A．are more sensitive to new words | B．respond actively to strange sounds |
| C．show a higher level of neural activity | D．become excited at the familiar words |
| A．Yes, Your Dog Is Very Smart | B．Yes, Your Dog Does Understand You |
| C．Yes, Your Dog Does Try to Please You | D．Yes, You Can Communicate with Your Dog |
【推荐1】Are you wondering whether it’s worth going for a little jog? Don’t hesitate, and get your sports shoes on. A new study shows that proper running lowers the risk of premature (过早的) death.
In an analysis of 14 previous studies from the US and Denmark, the group of researchers from institutes in Australia and Finland concluded that increasing running participation would probably lead to substantial improvements in population health and longevity. The studies involved 232,149 participants over time periods ranging from 5.5 to 35 years.
Overall, people running any distance were associated with a 27% lower risk of death from all causes than those who did not, the analysis shows. Running was also associated with a 30% and 23% lower risk of death from cardiovascular (心血管的) disease and cancer, respectively.
Previous studies had concluded “inconsistent findings” about whether running could lower the risk of premature death, according to the researchers. Lead researcher Jim White, a professor at Victoria University in Melbourne, told CNN, “Our recent findings may motivate physically inactive individuals to take up running and those who already run to keep on doing it.”
He added that doctors may be encouraged by our findings to promote running as a part of “lifestyle medicine”. In their paper, which will be published in the British Journal of Sports Medicine, the researchers say health professionals are sometimes wary of promoting running because vigorous (剧烈的) use of it has been linked with sudden cardiac death.
Jim and his team countered this by noting that the benefit of running outweighs the risk. However, they did say advice should be given on a case-by-case basis, as running might not be appropriate for everyone. Although running has a clear overall health benefit, the researchers point out that higher “doses” of running may not reduce the risk of premature death further. According to the WHO’s guidelines, adults aged between 18 and 64 should take 150 minutes of gentle exercise or 75 minutes of vigorous exercise each week.
1. What did the new study focus on?| A．The benefit of jog. | B．People’s lifestyles. |
| C．People’s living conditions. | D．The popularity of jog. |
| A．Researchers’ promotion of sport. |
| B．People’s involvement in running. |
| C．Doctors’ quicker treatment. |
| D．People’s losing weight. |
| A．Certain. | B．Capable. |
| C．Confident. | D．Cautious. |
| A．The risk of exercising vigorously. |
| B．The suggestion on running appropriately. |
| C．The reason why people should keep running. |
| D．The argument about whether running benefits people. |
【推荐2】From a very early age, some children exhibit better
self-control than others. Now, a new study that began with about 1, 000 children in New Zealand has tracked how a child’s low self-control can predict poor health, money troubles and even a criminal record in their adult years.
Researchers have been studying this group of children for decades now. They observed the level of self-control the youngsters displayed. Parents, teachers, even the kids themselves, scored the youngsters on measures like “acting before thinking” and “Persistence in reaching goals.”
The study led by Moffitt of Duke University and colleagues followed 1, 000 children from birth to age 32 in Dunedin, New Zealand.
“The children who had the lowest self-control when they were age three to ten, later on had the most health problems in their 30s, ” Moffitt said, “and they had the worst financial situation. They were more likely to have a criminal record and to be raising a child as a single parent on a very low income.” Moffitt explained that self-control problems were widely observed, and weren’t just a feature of a small group of misbehaving kids.
Moffitt said it’s still unclear why some children have better self-control than others, though she said other researchers have found that it’s mostly a learned behavior, with relatively little genetic influence. But good self-control can be set to run in familles because children with good self-control are more likely to grow up to be healthy and prosperous parents. But the good news, Moffitt said, is that self-control can be taught by parents, and through school curricula that have been shown to be effective.
1. From the first two paragraphs we learn that ________.| A．the research has been carried out for five years |
| B．self-control in kids tends to determine their future |
| C．self-control was assessed by children’s intelligence |
| D．children’s self-control is almost the same at early age |
| A．become wealthy in later life | B．get good school performance |
| C．have better financial planning | D．adopt negative behaviors |
| A．only good genetic factors can shape their lives in the future |
| B．scientists know well why some children have better self-control |
| C．self-control in childhood has nothing to do with criminal activity |
| D．willpower as a child really influences people’s chances of adulthood |
| A．Self-control cannot be taught in schools. |
| B．The study is restricted within few participants. |
| C．It’s never too late to deal with self-control problems. |
| D．Good parenting can improve self-control and life success. |
| A．Child’s self control predicts future health, success |
| B．Kids are encouraged to take risks at an early age |
| C．Children’s development cannot be changed by teachers |
| D．How to teach the kids a bit of self-control in schools |
【推荐3】Diet containing lots of salt can contribute to increased levels of stress, a new study shows. Scientists found in studies of mice that a high-salt diet increased the levels of a stress hormone by 75 per cent. Experts hope the findings will encourage a review of public health policy around salt consumption, aiming at manufacturers reducing the amount of salt in processed food.
The recommended salt intake for adults is less than six grams a day but most people regularly eat about nine grams. This can contribute to higher blood pressure, which increases the risks of heart attacks, strokes and dementia.
While effects on the heart and circulatory(循环) system have been ascertained, little was known about the impact of a high-salt diet on a person’s behaviour. To study this, experts from the University of Edinburgh used mice, who ordinarily have a low-salt diet, and gave them high-salt food to reflect the typical intake of humans.
They found that not only did resting stress hormone levels increase, but the mice’s hormone response to environmental stress was double that of mice that had a normal diet. Salt intake increased the activity of genes that produce the proteins in the brain which control how the body responds to stress.
Experts say further studies are already underway to understand if a high-salt intake leads to other behavioural changes such as anxiety and aggression. Matthew Bailey, professor of Renal Physiology at the University of Edinburgh’s Centre for Cardiovascular Science, said: “We are what we eat and understanding how high-salt food changes our mental health is an important step to improving wellbeing. We know that eating too much salt damages our heart, blood vessels(血管) and kidneys. This study now tells us that high salt in our food also changes the way our brain handles stress.”
1. What are the findings expected to bring about eventually?| A．Manufacturers adding less salt to processed food. |
| B．People debating the policy on public health. |
| C．Decreased levels of stress hormones. |
| D．Reduced amount of processed food. |
| A．Ignored. | B．Restored. |
| C．Reduced. | D．Confirmed. |
| A．What policy on salt should be. |
| B．How a high-salt intake affects blood pressure. |
| C．How much salt intake is appropriate. |
| D．Whether a high-salt intake causes anxiety. |
| A．Most people regularly take in too much salt. |
| B．Mental health is important to improving well being. |
| C．Diet containing much salt increases levels of stress. |
| D．Less than six grams of salt a day is recommended. |
【推荐1】The Chinese version of TikTok-Douyin is introducing a “teenage mode” that will limit the amount of time children under the age of 14 spend on the short-form video app to 40 minutes a day.
The measure will apply to all Douyin users under the age of 14 who have registered for the app using their real names, Beijing-based ByteDance announced in a statement on Saturday.
Douyin will also be unavailable to those users between 10 p.m. and 6 a.m., the owner of TikTok and Douyin added.
The company also urged parents to help their children register with real names, or otherwise manually enable “teenage mode.” ByteDance did not immediately respond to a question from CNN Business about how it might enforce (执行) the- policy for those who don’t use then real names.
The app also said it would introduce new content-ranging from science experiments and museums to art gallery exhibition and natural scenery-by ByteDance to get ahead of potential regulation analysts at Citigroup Global Markets wrote in a Monday research note. They suggested that the decision could push other internet platforms with short video content to look at implementing similar restrictions.
“Self-assessment and voluntary implementation (履行) of minor-protection measures by more platforms could help suggest platforms are being more socially responsible and potentially reassure parents and regulators,” they added.
Douyin had at least 490 million users in November 2020, according to media research firm iiMedia Research.
Chinese regulators have already started pressuring tech companies to curb the amount of time minors spend on their services.
In June, China revised its “Minor Protection law,” which requires internet service providers including social media apps-to “set-up corresponding functions such as time management, content restriction and consumption limits for minors.”
Douyin’s rival Kuaishou-which is backed by Tencent-introduced a similar setting for minors in2019.
China’s pressure on tech companies is part of sweeping new regulations on businesses focused on the next generation, from a heavy crackdown-on-private tutoring to rules for online gaming.
Last month, the country barred online gamers under the age of 18 from playing on weekdays and limited their play to just three hours most weekends.
1. Which is the best title of the passage?| A．Tech companies are limiting entertainment. |
| B．Tech companies are facing a lot of pressure. |
| C．Douyin is limiting kids to 40 minutes a day. |
| D．Young generation is banned from short videos. |
| A．save | B．control |
| C．increase | D．minimize |
| A．Because it is required by Chinese regulators. |
| B．Because it fits the current trend in regulations. |
| C．Because it can appeal to more young people. |
| D．Because it can help grab more market share. |
| A．Children under 18 will not be able to use Douyin on weekdays. |
| B．The “teenage mode” aims to help students focus 0on studies. |
| C．Kuaishou is the first company to introduce setting for minors. |
| D．There still exists some problem about “teenage mode”. |
【推荐2】My favourite book is The Adventure of Tom Sauyer by Mark Twain. Tom lives with his aunt Polly in a quiet street of St. Petersburg, Missouri. He’s a lively and clever young boy, and he finds himself in many exciting adventures. He runs away with his two friends, Huck Finn and Joe, to an island in the middle of the Mississippi River for several days. With Huck he goes looking for treasure, with Becky he gets lost in a cave. And finally, they find a box of gold.
My favourite scene in the book is when everyone thinks Tom is dead. He decides to go to his own funeral(葬礼). He hides and watches for a time and then suddenly he appears. Everyone is surprised to see him but they’re also pleased to see him alive.
Tom is the hero of the story, but there are other important characters. Huck is an outsider and everyone is afraid of him. Becky is pretty with fair hair, Joe is Tom’s best friend. And Injun Joe is the bad man of the story.
The theme of the story is about children growing up. It describes how strangers are seen in small towns of America. Finally, it talks about freedom, social rules and how people are punished for bad behaviour.
Why do I think The Adventure of Tom Sawyer is a great book? Mark Twain wrote the story in 1876, but it’s still read and loved by people all over the world today. And although it’s only a story, Twain wrote it in the everyday English of the southern states of America in the 19th century, so it sounds very real. Today its thought to be one of the greatest books in American literature. Go on-read it! I know you’ll enjoy it, too.
1. Where does Tom run away with his two friends?| A．To a quiet street. | B．To a small town. | C．To an island. | D．To a forest. |
| A．Huck Finn. | B．Joe. | C．Becky. | D．Polly. |
| A．They were surprised and happy. |
| B．They were surprised and sad. |
| C．They were worried and excited. |
| D．They were frightened and happy. |
| A．To recommend the book for you. |
| B．To explain the history of America. |
| C．To tell us when Mark Twain wrote the story. |
| D．To explain why the story sounds very real. |
【推荐3】Hacking (侵入) isn’t just for computers or smart phones. According to a study published last week in Science, scientists have found a way to hack a plant’s genes in order to make it use sunlight more quickly. Someday, the result could increase the amount of food produced around the world.
Scientists who did the new study believe photosynthesis (光合作用) is a very slow process. Plants use less than one percent of the energy available to them. But by hacking a plant’s genes the scientists are able to increase the amount of leaf growth on plants between 14 and 20 percent.
Specially, scientists hacked the plant’s protective system. Normally, this system can be useful when a plant gets too much sunlight. When the plant senses the light, it removes extra energy and creates more leaves. When the plant can’t meet light, the protective system is turned off. But the process is slow. Stephen Long is the lead author of the study. He compared a plant’s protective system to light-adjusting glasses. “When a person wears the sunglasses outside during the day, the sunglasses darken and lighten depending on how sunny it is. Plants do the same thing,” he said. But in plants, the adjustment can take place anywhere, which lasts from 10 minutes to an hour. This makes it hard for plants to get the right amount of sunlight needed to create food.
The new study sped up the process. By changing the plant’s genes, the protective system turned on and off more quickly. As a result, leaf growth on the plants scientists used in the study increased. Leaf growth on two plants increased by 20 percent, while leaf growth on third plants increased by 14 percent. Scientists did the study on tobacco plants. But they think the genetic modification would produce the same results on corn and rice plants. Agriculture professor Tala Awanda said the study made senses, but cautioned the production might not be quite so high for traditional food crops. Still, she added in an email, “This study remains a breakthrough.”
1. What will happen when the plants’ genes are hacked?| A．The plants will use sunlight more properly. |
| B．The plants will remove the energy quickly. |
| C．The plants will turn on their protective system. |
| D．The plants will work faster to produce more food. |
| A．By making plants get less sunlight. |
| B．By using computers and smart phones. |
| C．By making photosynthesis become slow. |
| D．By changing the protective system of plants. |
| A．To warn people of the hot and bright sun. |
| B．To explain the usage of plants’ protective system. |
| C．Just to better understand how sunny it is every day. |
| D．Just to talk about the adjustment of sunglasses to the sun. |
| A．Critical. | B．Negative. | C．Objective. | D．Doubtful. |
【推荐1】People speak English in different parts of the world. The same words can be used in different ways, depending on where you live. People can also have completely different ways of saying the same thing.
The Oxford English Dictionary(OED) is asking the public to help it add new words. Editors want to find the regional differences in English around the world. They want to expand its record of the language.
Last year, the OED, BBC Radio and the Forward Arts Foundation teamed up to find local words in the United Kingdom. It resulted in more than 100 regional words and phrases being added to the dictionary. One was “cuddy winter”, which means a left-handed person.
Now, the OED is widening its search to English speakers around the world. Eleanor Maier, an editor at OED, said the response has been great. Editors are listing a bunch of suggestions to include in the dictionary.
These include Hawaii's “hammajang” which means “in a disorderly state”. Another is the word for a swimming costume, " lookers" or “duckers”. It is used in Scotland.
The OED also might include the word “ frog-drowner” , which Americans might use to describe a downpour of rain. Another possibility is “brick”. It means “very cold” to people in New Jersey and New York City.
The dictionary has already found that, depending on location, a picture hanging off center might be described as “agley”. It might also be called “catawampous” or “ahoo”.
“The OED aims to cover all types of English,” Maier said. That includes scientific words, slang and regional language. Maier also said that it can be difficult for the OED's editors to identify regional words. The terms are more often spoken than written down.
The appeal is called Words Where You Are. It is looking for more suggestions. “We were surprised and pleased by the number of regional words we were able to include,” said Maier.
1. "Cold" is closest in meaning to .| A．hammajang | B．dockers | C．brick | D．ahoo |
| A．agley | B．frog-drowner | C．cuddy winter | D．brick |
| A．It is challenging to create a complete collection of regional words. |
| B．People pay little attention to the appeal for regional words. |
| C．People use regional words only when they are home or with close friends. |
| D．Having an understanding of regional words can be helpful when communicating. |
| A．It's time to trace the source of local words. |
| B．The same English words can be used to say different things. |
| C．Oxford Dictionary aims to enlarge its collection to appeal to locals. |
| D．Oxford Dictionary will include more regional words from around the globe. |
【推荐2】Catching up with e-mail while you eat lunch? Watching television? How often do you eat while doing something else like checking out a web site or watching television?
Results of a recent study indicate that distracted (注意力分散的) eaters are less able to recall what they ate and more likely to snack later. As an alternative, mindful eating may help you avoid extra pounds and unnecessary snacking. Researchers had 22 volunteers eat a meal while playing computer games and 22 others eat the same meal in the same amount of time while undistracted. They told the subjects it was a test of the effect of food on memory, but actually they were testing how full people felt after a meal, how much they ate at a “taste test” 30 minutes later, and how successfully they could recall exactly what they ate.
Results showed that those who ate while distracted felt significantly less full just after the meal, and they were worse at remembering what they had eaten than those who were not distracted. In addition, at the taste-test session 30 minutes later, distracted eaters consumed twice as many cookies as those who were not distracted. The senior author Jeffrey advises, “Avoiding eating in front of a computer screen might temper the tendency to snack later in the day. Memory plays an important role in the regulation of food intake,” he said, “and distractions during eating ruin that.
So, after reading this article, you definitely know the easiest way to keep fit. If you want to watch your waistline, it’s wise to focus on the food before you.
1. What do we know about the study?| A．It is a two-session test. |
| B．It lasted for 30 minutes. |
| C．22 volunteers took part in it. |
| D．The volunteers knew its purpose. |
| A．prove harm of snacks |
| B．select the most delicious snack |
| C．advocate a healthy eating habit |
| D．find out relation between food and memory |
| A．Tend to have snack. | B．Be less likely to snack. |
| C．Change the attitude to snacking. | D．Have a good temper after snacking. |
| A．Focusing on the food helps you keep fit. |
| B．Eating while watching TV does harm to health. |
| C．Memory plays an important role in losing weight. |
| D．Undistracted eating leads to consuming more food. |
【推荐3】Few people can refuse a delicious ice cream, especially on a hot day. The only thing that stops the fun is that the treat is hard to enjoy slowly, ending up with a sticky, melted mess. Now, researchers from Colombia’s Pontifical Bolivarian University may have found an unlikely thing to help solve this age-old problem — a kind of fibre from banana plant waste.
Bananas, as you probably know, grow in groups on a tree-like plant. Each group is connected to a central rachis (叶轴), which is thrown once the fruit has been gathered. The team, which was led by Dr. Robin Zuluaga Gallego, began by abstracting /drawing out cellulose nanofibrils (CNFs) from the powdered rachis. The tasteless fiber, thousands of times smaller than the width of a human hair, was then added to 100 grams of ice cream mix.
With the right amount of CNFs mixed in, the dessert lasted longer in its frozen state than the traditional ice cream, extending the amount of time that the treat can be enjoyed. What was even more exciting was that the fibre increased the stickiness of the low-fat ice cream to levels higher than the full-fat one. Since this is what determines the frozen treat’s creaminess and taste, CNFs could help create the healthier ice cream without influencing the taste of it.
The researchers, who presented their findings at the American Chemical Society( ACS) meeting in New Orleans in March, 2018, next plan to study how different types of fat, such as coconut oil, influence the behaviour of CNFs in other frozen treats.
The Colombian researchers are not the only ones working on creating a slower-melting ice cream. In 2015, scientists at the University of Dundee in Scotland found that a natural protein called BsIA was very effective in keeping the treat frozen for longer periods of time. With both teams fighting to be the first to get to the market, the future of everyone’s favorite dessert certainly looks bright.
1. What prevents people enjoying an ice cream slowly?| A．A kind of fibre from bananas. |
| B．The ice cream’s quick melting. |
| C．The ice cream’s stickiness. |
| D．The fat in the ice cream. |
| A．To improve its taste. |
| B．To increase its stickiness. |
| C．To reduce its fat content. |
| D．To make it melt more slowly. |
| A．The ice cream. | B．The fiber. |
| C．The fat. | D．The stickiness. |
| A．BsIA is popular in the market. |
| B．CNFs are more useful and expensive than BsIA. |
| C．Ice creams with CNFs have been on sale at the market. |
| D．Slowly enjoying an ice cream will soon become a reality. |
