Cells in our brain usually send a “stop eating” signal when we've eaten enough. But in a study, researchers found that after mice ate fatty food for just two weeks, their brains brake on overeating failed.
Researchers at the University of Washington in Seattle conducted the study.They shared their findings in Science.Garret Stuber is a professor at the University of Washington.He and his team mainly focused on one brain area known-to be connected with eating behavior.This brain area contains many different kinds of cells.Researchers noticed big differences between the glutamatergic nerve cells(谷氨酸神经细胞)of the fat mice and those of the thin mice.And the earlier work by Stuber's group had suggested that these cells act like a brake on overeating.When the researchers stopped these cells from working,mice suddenly overate.They also fattened up. But it wasn't clear how these cells' activity changed as the mice changed from being slim to being fat.
“Being fat doesn't just happen overnight,”notes Stuber.To study that gradual fattening up,his group did a new study.They fed mice with high-fat food.Now and again,they used a microscope to look at how well the animals 'glutamatergic nerve cells could send out signals.During the process,they found the activity of these glutamatergic nerve cells slowed,even before the mice became fat.That cell sluggishness(怠惰)continued as the mice grew larger over a 12-week period.
The results suggest that the high-fat diet is removing the brake on overeating and becoming fat,”says Stephanie Borgland,a professor at the University of Calgary in Canada. Stuber's group doesn't know whether these brain cells will go back to normal if the mice stop eating the fatty food and slim down.It would be hard to keep monitoring the same cells over the months it would likely take for the mice to return to a healthy body weight,”explains Stuber.And it's hard to say whether similar cells control the same thing in humans.
“Having high-fat diets probably affects a much wider family of cells than those studied here,” Stuber notes. “Changes,” he says, “are probably happening across the brain.” Understanding those things might help us find better ways of limiting overeating.
1.What did researchers find in the study?
A.Mice tended to become sluggish if they often overate.
B.Having high-fat diets affected many kinds of brain cells.
C.Mice began to overeat after eating fatty food for a period.
D.The number of brain cells would drop when mice overate.
2.Why was a new study conducted?
A.To prove that fatty food was bad for health.
B.To know more about that gradual weight-gain.
C.To collect more information about the mice 's cells.
D.To observe how long it would take for the mice to grow fat.
3.What does the last but one paragraph mainly show?
A.It's still difficult to answer some questions.
B.It's hard to find the similar brain area in humans.
C.It's wrong to apply what suits animals to humans.
D.It's necessary to keep monitoring the mice for long.
4.Where is this text most likely from?
A.A personal diary.
B.A useful guidebook.
C.A science magazine.
D.An adventure novel
Fire Prevention Information
The University of Adelaide employs a full-time staff of fire prevention professionals. They inspect all campus buildings and test and maintain all sprinkler(喷水灭火装置)systems, fire alarms and fire extinguishers(灭火器).They also provide educational programs or fire safety in the residence hall. Whenever you move to a new area, you should locate the fire alarm purl stations and the two exits nearest your room.
Fire Alarms
The floors of all campus buildings are equipped with manual fire alarm systems which include fire alarm pull stations and pipes.Most are also equipped with automatic fire alarm systems consisting of heat detectors,smoke detectors and sprinklers.For your safety,never tamper with(胡乱摆弄)these systems.False fire alarms are illegal and may lead to imprisonment.
Fire Drills
A fire drill will be conducted in your residence hall every semester.During a fire drill,please do the following:
Take your room key and ID,close and lock the door to your room.
Exit immediately from the nearest emergency exit;do not use a lift.
Meet outside of your residence hall and wait for further instructions.
Fire Extinguishers
Fire extinguishers are located on each floor and in each apartment.Use a fire extinguisher only if you have been trained to do so.Irresponsible use of a fire extinguisher can create a dangerous situation for other residents and could result in damage to personal property.Misuse of a fire extinguisher will result in fines.
Smoke Detector
A smoke detector is on the ceiling in your room.Some buildings also have heat detectors on the ceilings.Do the following to ensure the safe operation of your smoke detector:
If your smoke detector is working properly,the red light should be on.If the red light is not blinking(闪动)，contact residence hall staff immediately.
Do not cover or block your smoke detector in any way.
If a smoke detector sets off an alarm and there is no fire or smoke,inform your hall staff.
1.What is the main duty of the fire prevention professionals?
A.To provide part-time jobs for students.
B.To lead the students to the nearest exits.
C.To check and maintain fire prevention equipment.
D.To train teachers to be fire prevention professionals..
2.What do the automatic fire alarm systems include?
A.Pipes and smoke detectors.
B.Smoke detectors and sprinklers.
C.Fire alarm pull stations and pipes.
D.Sprinklers and fire alarm pull stations
3.What do we know about the use of fire extinguishers?
A.Using them wrongly results in punishment.
B.Irresponsible use of them can damage them.
C.Improper use of them can destroy the apartment.
D.Using them without a trainer present is forbidden.
听下面一段独白，回答以下小题。
1.According to the passage,what were dogs trained for in the past?
A.For protection against other animals.
B.For protection against other dogs.
C.Just for fun.
2.Why were dogs used for hunting?
A.Because they did not eat other animals.
B.Because they were useful for protection.
C.Because they always obeyed their masters.
3.What is the most important reason for people in the city to keep dogs now?
A.For companionship.
B.For amusement.
C.For protection against robbery.
听下面一段较长对话，回答以下小题。
1.Where are the man and the woman going?
A.To the bus station. B.To the police station. C.To the railway station.
2.What does the woman think they should do?
A.Take a taxi. B.Walk slowly. C.Leave the bags with the police.
3.What does the man find out at last?
A.Fifteen minutes is too long.
B.The traffic is moving too slowly.
C.He is not able to carry two bags.
听下面一段较长对话，回答以下小题。
1.What is NOT true about the man?
A.Water is running down his leg.
B.He can not breathe well after a walk.
C.He hasn't been sleeping well because of the pain in his leg.
2.What has caused the trouble?
A.The woman doesn't know yet.
B.He was burnt by boiling water.
C.He has tired himself out in his work.
3.What's the woman's name?
A.Doctor Cook. B.Doctor Martin. C.The conversation doesn't tell us.
听下面一段较长对话，回答以下小题。
1.What are the man and the woman talking about?
A.A film. B.A real story. C.A ghost story.
2.What's the first name of the man they are talking about?
A.Tim. B.Tom. C.Smith.
3.Why didn't the man return home after the war?
A.He had been wounded in the war.
B.The man hasn't told the woman yet.
C.He had to sell newspapers at the railway station.
