Caribbean box jellyfish (水母) can learn to spot and avoid obstacles (障碍) despite lacking a central brain, according to a new study. This is the first evidence that jellyfish can do something called associative learning. The nervous systems of Caribbean box jellyfish are fairly simple, including four “rhopalia (视神经束)”on a jellyfish’s body, each of which has six “eyes”, by which the jellyfish judge a mangrove root’s distance based on how dark it looks compared to the water and make their way round it. In common waters, nearby roots have high contrast. Only distant roots fade into the background. But in murky waters, even near-by roots can blend into their surroundings and have low contrast. The researchers wondered if Caribbean box jellyfish could learn that low-contrast objects-which might at first seem distant-were actually close by.
To find out, the team put 12 jellyfish into a round water tank. The tank was surrounded by low-contrast gray and white stripes (条纹), which might appear to a jellyfish like roots in clear water. A camera filmed the animals for about seven minutes. At first, they seemed to see the gray stripes as distant roots and swam away, ending up bumping the tank wall. But those collisions (碰撞) seemed to lead the jellyfish to reconsider the stripes. Soon, the creatures treated the gray stripes more like close roots in murky water-and avoided them.
This suggests that the rhopalia alone can learn that seemingly distant, low-contrast objects are in fact close enough to avoid. That, in turn, hints that these nerve centers are behind Caribbean box jellyfish learning.
“That’s the coolest part of the paper,” says Ken Cheng, a biologist at Macquarie University, Sydney, Australia. “That gets us one step down into the wiring of how it works.” For Gaëlle Botton-Amiot, tracing learning to the rhopalia raises new questions. “They have four of these things in their bodies. So how does that work?” asks this neurobiologist. If a jellyfish loses one of its rhopalia, does it forget everything those eyes saw and the neurons had learned? Or do the other rhopalia remember it?
1. Jellyfish are able to avoid obstacles because ______.A.they use brain cells to process information gathered |
B.they rely on different levels of visual signal input |
C.they have unique organs to measure the distance |
D.they are driven by excellent survival instinct |
A.Unusual. | B.Cloudy. | C.Deep. | D.Rapid. |
A.Jellyfish usually tend to be scared off by the gray color. |
B.Jellyfish tend to compare stripes with mangrove roots. |
C.Stimulation in controlled environment backed the finding. |
D.Rhopalia are in control of the jellyfish’s memory system. |
A.No brain, no gain? Denies the jellyfish |
B.Unique “eyes” help jellyfish survive |
C.Evolution of learning: from nerve to brain |
D.White or gray? Creature’s decision-making |
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【推荐1】Have you ever heard of underwater football? Underwater football has been called one of the world’s least-known sports.
The goal of the game is to score a point by placing a ball on the opponents’ side of the pool. The ball can only be possessed by players who completely stay underwater holding their breath.
Just like on land, underwater football is a game of control and possession.
To win the ball back or keep it away from your opponents, you must use all your strength and abilities underwater.
A.To play it you need snorkeling equipment. |
B.Underwater football involves two teams of five players. |
C.The equipment necessary for underwater football isn’t very complex. |
D.The ball must be passed or dropped when players go to the surface for air. |
E.It is a sport that combines the fundamentals of football with the excitement of diving. |
F.To play well, you need to master the basics of spacial awareness and decision-making. |
G.All these skills require practice if you want to become an expert at this exciting sport. |
【推荐2】Are you somebody who can’t wake up in the morning? Do you need two cups of coffee before you can start a new day? Do you feel awful when you first wake up? Scientists say it’s all because of our genes(基因).
They discovered that we all have a “clock” gene, also called a PER3 gene.
A.How did they find this out? |
B.As soon as you wake up, wash your face and step outside. |
C.How does it help us to know we have the long or short gene? |
D.This gene can be long or short. |
E.It is common for people to feel sleepy in the morning. |
F.Scientists then compared their answers to the people’s DNA. |
G.So maybe, instead of nine to five we should work from seven to three or twelve to eight. |
【推荐3】Look at the center circles of Diagram A and Diagram B. Which of the center circles looks larger? In Diagram B? In fact, they are exactly the same size.
Then look at the picture on the right. What do you see? A vase? Or two faces?Does the picture change quickly from one to the other again and again? Maybe or maybe not, but you can never see them at the same time.
“What’s happening? Is something wrong with my eyes?” You may wonder at what you see.
Don’t worry. Here is how it goes:
When we look at things, our eyes send messages to our brains and then our brains interpret the information. However, sometimes our brains interpret the received information in a wrong way. It seems that our eyes are playing a joke on us. This often happens and we call it “visual illusion (错误)”.
1. Why does the center circle in Diagram A look smaller than that in Diagram B?A.Something is wrong with our eyes. |
B.The two circles are not the same size. |
C.The two pictures change quickly from one to the other. |
D.Our brains interpret the information in a wrong way. |
a. We look at things with our eyes.
b. Our brains interpret the messages.
c. Our brains tell us what we have seen.
d. Our eyes send messages to our brains.
A.c a b d |
B.a d b c |
C.a c d b |
D.b c a d |
A.To make the actors seem different in size. |
B.To make the actors much braver. |
C.To help the actors become stronger. |
D.To help the actors look better. |
【推荐1】Rescuing victims from a burning building, a chemical spill, or any disaster that is inaccessible to human responders could one day be a task for adaptable robots. Imagine, for instance, rescue-robots rising up on two legs can bound through rubble, push aside a heavy obstacle, or break through a locked door.
Engineers are improving the design of four-legged robots and their abilities to run, jump and even do back leaps. But getting two-legged, human-like robots to use force or push against something without falling has been a lion in the way.
Now engineers at MIT and the University of Illinois at Urbana-Champaign have developed a method to control balance in a two-legged, tele-operated robot — an essential step toward enabling a human-like to carry out high-impact tasks in challenging environments. The team's robot, physically resembling a machined body and two legs, is controlled remotely by a human operator wearing a vest that sends information about the human's motion and ground reaction forces to the robot. Through the vest, the human operator can direct and experience the robot's movements. If the robot is starting to tip over, the human feels the same pull on the vest and can adjust in a way to rebalance both himself and the robot.
In experiments with the robot to test this new "balance feedback" approach, the researchers were able to remotely maintain the robot's balance as it jumped and walked in sync with its human operator.
“It's like running with a heavy backpack ——you can feel how the dynamics of the backpack move around you, and you can make up properly," says Joao Ramos, who developed the approach as an MIT post doctor. “Now if you want to open a heavy door, the human can command the robot to throw its body at the door and push it open, without losing balance. ”
1. What's the function of the first paragraph?A.Draw people's attention to a new robot. | B.Show the appearance of the robot. |
C.Tell the principle of the two-legged robot. | D.Introduce the purpose of the two-legged robot. |
A.It's hard for them to do back leaps. | B.It's hard for them to keep their balance. |
C.They can't push against anything hard. | D.They often fall back when meeting the lions. |
A.The tested robot's actions can be felt by the human operator. |
B.The robot is tested in challenging environments by operator. |
C.The data on the tested robot is sent by telephones. |
D.The tested robot has a remote voice-control system. |
A.The two-legged robot is worse than the four-legged robot. |
B.The vest must be put into the machined body. |
C.The new research on the robot has made great breakthrough. |
D.The robot's movements must be controlled by human operator. |
【推荐2】The film, recording lots of people killed by Japanese troops in Nanjing, was shot secretly by the US priest John Magee (1884-1953).
As pastor at Daosheng Church of Nanjing and later the chairman of the International Commission of Nanking Red Cross Organization, John Magee remained in the city along with another 20 Westerners in December 1937. He helped establish the Nanjing Safety Zone, which is estimated to have sheltered around 200, 000 Chinese and saved many thousands of lives during the Nanjing Massacre (屠杀). While helping Chinese refugges escape Japanese atrocities, Magee also used his 16mm movie camera to record evidence of Japanese war crimes.
The Japanese had banned any street photography or filming, but Magee took a risk and managed to secrectly shoot 105 minutes of videos. He photographed such scenes as women in agony after being raped and beaten by Japanese invaders, severely injured locals being treated in hospitals and the cruel murders in the city. Many scenes in his film have been later edited into related war documentaries.
When Magee passed away in 1953, his 16mm camera and the film were left to his son David Magee, who came to Nanjing in 2002 and donated the camera and related historical materials to the Memorial Hall of the Victims in Nanjing Massacre by Japanese Invaders in Nanjing.
His film recording seven members of Xia Shuqin's family killed later also served as important evidence in the family’s survivor Xia’s decade-long battle to win over the libel suit (诽谤诉讼) in 2009 against Japanese rightist scholar Shudo Higashinakano and author Magsumura Goshio, as well as publisher Tendensha, for books that claimed Xia was a false witness to the massacre.
1. Which of the following statement about John Magee is NOT TURE?A.He succeeded in secretly shooting 105 minutes of pictures. |
B.He donated the camera and related historical materials to China. |
C.He helped establish the Nanjing Safety Zone to save around 200, 000 people. |
D.He used his 16mm movie camera to record evidence of Japanese war crimes. |
A.Little inspiration. | B.High confidence. | C.Terrible pain. | D.Endless pleasure. |
A.Funny. | B.Right-minded. | C.Brave. | D.Helpful. |
A.Important evidence that Xia Shuqin won the libel suit in 2009. |
B.Important evidence that lots of people had been killed by Japanese. |
C.Important evidence that seven family members of Xia's had been killed. |
D.Important evidence that claimed Xia was a false witness to the massacre. |
【推荐3】We all have problems and barriers (障碍) that prevent us from moving into new areas. When someone meets the problem which he can’t get over, he usually turns away and starts walking along a different path. Unluckily, soon he may get into another similar one. In this way, his life stays inside the same old cycles, in which he is unlikely to make progress or keep learning.
While others deal with problems by loving them instead of hating them. The word “love” means accepting your problems. The more we deny (否定) a problem, the stronger it seems to become. Only when we accept the fact can we find the useful ways to deal with it.
Suppose one of your barriers is taking a final exam. You fear that you will forget everything that you have remembered. One way of dealing with it is to pretend (假装) that you are not afraid—tell yourself “I’m not going to be scared ”and then try to force a smile on your face.
But compared with that, loving your fear actually works better. You just need to say to yourself, “I’m scared. But I’m going to take it easy. It is not only a problem, but also a chance for me to make progress.” By doing that, you allow yourself to be afraid and you can have a right understanding to your problem. You welcome your problem and face it in an active way. So there’s no doubt that you are more likely to overcome it completely.
It is impossible to live a life without problems. Loving them doesn’t mean hiding them. Instead, it means admitting the truth about them. This helps us take effective (有效的) actions, which can free us from the problems once and for all.
1. If our lives stay the same, we are unlikely to ________.A.make progress or keep learning | B.deal with the problem |
C.meet difficulties | D.force a smile on the face |
A.try to find a different path | B.avoid another similar problem |
C.accept the problem first | D.try to deny the problem |
A.Accepting. | B.Refusing. |
C.Praising. | D.Remembering. |
A.How to Deal with a Problem | B.How to Make Progress |
C.How to Avoid Difficulties | D.How to Become Confident |