Scientists have exactly discovered the set of brain cells involved in making risky decisions, and have been able to control them in rats using targeted light. By changing the activity of the cells they were able to change the behaviour of risk-taking rats to avoid risk, hinting the approach could in future be used to treat people with impulse (冲动) control problems.
Risk-taking is a key part of survival, knowing when to take a chance could pay off—such as moving to a new area to look for food when pickings are slim.
While all animals need an element of risk, the preference towards it varies between individuals. Researchers found this variation, which determines how risk-averse an individual is, is regulated by brain cells in a region of the brain called the nucleus accumbens. This cluster of neurons releases the neurotransmitter dopamine, which regulates the brain’s reward and pleasure centres.
Previous studies have shown that in patients with Parkinson’s disease, taking medication which blocks specific dopamine receptors (DR2) (受体) leads to increased gambling (赌博) behaviour and risk taking behaviour. In studies with rats, researchers were able to use a technique called optogenetics (光遗传学)—which uses light sensitive proteins to change the activity of cells—to modify cells with DR2 in the nucleus accumbens.
Rats were trained to choose one of two levers, offering them a choice between a “safe” or “risky” choice. The safe option resulted in a small, but consistent amount of a sugar water treat. But the risky choice consistently delivered smaller amounts of sugar water, with the occasional large pay off—essentially encouraging the animals to gamble for a bigger prize. Around two-thirds of the animals weren’t keen on risk, opting for the safe option, but the remaining third were risk-seekers. Brain scans of the animals showed that those with low levels of DR2 consistently went for the gamble.
But using pulses of light to stimulate (刺激) the DR2 cells and improve their activity could cause the risk-takers to play it safe and opt for the guaranteed but less rewarding option. Once the light-pulses stopped, the risk-takers returned to their gambling strategy.
In the risk-averse animals, stimulating the same cells had little to no effect.
Professor Karl Deisseroth, of Stanford University in California, said: “Humans and rats have similar brain structures involved.”And we found a drug known to increase risk preference in people had the same effect on the rats. So every indication is that these findings are relevant to humans. “Risky behavior has its moments where it’ s valuable. As a species, we wouldn’t have come as far as we have without it.”
1.The variation in people’s preference towards risks is directly regulated by ________.
A. nucleus accumbens B. light sensitive proteins
C. neurons D. dopamine
2.From the experiment with rats, we can conclude that ________.
A. the lack of DR2 cells results in a safe option
B. the levels of DR2 have little to do with their choices
C. the high levels of DR2 can make animals avoid risks
D. the risky choice is a less rewarding option
3.The underlined words in Paragraph 7 most likely mean the animals that are ________.
A. willing to take big risks
B. reluctant to take risks
C. fond of gambling strategy
D. afraid of receiving stimulation
4.What can be inferred from what Professor Karl Deisseroth said?
A. Humans and rats differ in their preference for risk-taking.
B. Too much risk-taking can do more harm than good.
C. Risk-taking can be used to treat people with impulse control problems.
D. Risk-taking is a means of survival and brings higher returns to humans.
Computer power is moving into the “cloud”—networks of data centres that use the Internet to supply all kinds of services, from e-mail and social networks to data storage and analysis.
The rise of cloud computing is rapid and causing huge changes in the tech industry. The old guard is suffering: this week’s $67 billion merger (合并) between Dell and EMC, makers of computers and storage devices respectively (分别), was a marriage forced by the rise of the cloud. Disruptive (捣乱的) newcomers are blooming: if Amazon’s cloud-computing unit were a stand-alone public company, it would probably be worth almost as much as Dell and EMC combined.
The gains for customers have been equally dramatic. Compared with older IT systems, cloud computing is often much cheaper. It adds tremendous flexibility: firms that need more computing capacity no longer have to spend weeks adding new servers and installing software. In the cloud they can get hold of it in minutes. Their applications can be updated continually, rather than just every few months. Individual users can reach their e-mails, files and photos from any device. And cloud services also tend to be more secure, since providers know better than their customers how to protect their computing systems against hackers.
But cloud computing makes one problem worse. In the old IT world, once a firm or a consumer had decided on an operating system or database, it was difficult and costly to switch to another. In the cloud this “lock-in” is even worse. Cloud providers go to great lengths to make it easy to upload data. They accumulate huge amounts of complex information, which cannot easily be moved to an alternative provider.
Cloud firms also create a world of interconnected services, software and devices, which is convenient but only for as long as you don’t venture (冒险) outside their universe. Being locked in to a provider is risky. Firms can start to tighten the screws by increasing prices. If a cloud provider goes bust (崩溃), its customers may have trouble getting back their data.
These risks have already caused a debate about whether the cloud needs stricter regulation. Some European politicians want to force cloud providers to ensure that data can be moved between them. That is too heavy-handed, because strict rules will inhibit (阻碍) innovation in what is still a young industry. The history of computing suggests that common standards may well appear naturally in response to customers’ demands—just as in personal computers, where it is now much easier to use the same files on different systems.
In the meantime, a few commonsense measures can reduce the risk of lock-in. Firms that use more than one cloud provider to host their data are less affected. So are those that keep their most important information in their own data centres. Consumers can take precautions, too. Some services are better than others at enabling users to move data between providers (Google does well on this score). Cloud computing promises its users many benefits, but don’t mistake it for some sort of digital heaven.
1.The author takes “the merger between Dell and EMC” for example to show ________.
A. the influence of cloud computing on computer and storage device makers
B. the miserable sufferings of old computer companies
C. the rapid development of new computer companies
D. the interaction between old companies and newcomers
2.With wide applications of cloud computing customers can ________.
A. pay less for the older IT systems
B. gain more computing capacity quickly
C. know better about defeating the hackers
D. install software within weeks
3.The problem of “lock-in” can be dangerous because ________.
A. it should ensure data can easily be moved to another provider
B. it can create a network of services connected with devices
C. it may make it difficult for customers to recover their data
D. it will discourage an argument about stricter rules
4.It can be inferred from the last two paragraphs that ________.
A. the European politicians’ advice is perfect
B. customers’ demands play a role in setting standards
C. lock-in is caused by firms’ storing information in their own centres
D. Google enables users to provide services and move data
5.Which of the following sayings can best express the main idea of the passage?
A. Everything has its time and that time must be watched.
B. The grass looks greener on the other side of the fence.
C. A candle lights others and consumes itself.
D. Every white has its black, and every sweet has its sour.
请认真阅读下面短文, 从短文后各题所给的A、B、C、D四个选项中, 选出最佳选项, 并在答题纸上将该项涂黑。
How many licks (舔) does it take to get to the center of a Tootsie Pop (棒棒糖)?
The first time I heard this in the Tootsie Pop commercial, I was five years old. I immediately started _________ and counting. After about two hundred licks or so, I stopped. The _________ of the chewy center had proven to be too great, and I _________ my way through the hard shell (外壳) to the very center. Besides, I _________ knew how many licks it took to get to the center—three. That’s how many licks it took the owl (猫头鹰) in the commercial to get to the center, so that, to me, was the _________ answer.
In high school, I held to the Tootsie Pop _________ . To me, the answer was still always three licks.
In my freshman year, I joined the Model United Nations _________ in my school. The Chair position had _________ the center of the Tootsie Pop and my _________ had become various other students. The first so-called “owl” was Eric who had luckily _________ the prestigious (声望高的) Chair position. So, I decided, _________ Eric reached the center in only one lick, that’s how many licks it should take me. I went to the tryouts with a view to obtaining the position but _________ .
At the end of my sophomore (高二) year, a new owl named Iris had _________ achieved the chair position after trying twice. I began working hard again. But then again, I did not make a _________ of it.
Now, slightly frustrated after _________ two owls, I found a new owl, Evan. It had taken him three licks to get to the “center”. Three was all I could _________. It was widely known that senior year was the _________ year to become Chair. I thought about _________ the program, but on second thoughts, I decided to continue.
Eleven years later, I visited the official Tootsie Pop website to find the real answer to the question that had _________ me my entire high school life. I finally understood. However many licks it takes to get to the center of the Tootsie Pop depends on however many licks I _________ to take—not how many the other owls take.
1.A. dreaming B. admiring C. licking D. chewing
2.A. temptation B. appearance C. power D. discovery
3.A. fought B. followed C. made D. bit
4.A. seldom B. never C. already D. nearly
5.A. brief B. right C. random D. temporary
6.A. commercial B. plan C. philosophy D. custom
7.A. program B. conference C. title D. activity
8.A. become B. changed C. determined D. explored
9.A. shell B. hope C. owl D. companion
10.A. noticed B. shifted C. improved D. landed
11.A. unless B. if C. before D. until
12.A. failed B. quitted C. survived D. struggled
13.A. yet B. even C. still D. also
14.A. promise B. success C. point D. joke
15.A. interacting with B. frightening away C. going through D. dealing with
16.A. afford B. hold C. admit D. expect
17.A. middle B. gap C. last D. initial
18.A. winning B. criticizing C. quitting D. arranging
19.A. motivated B. troubled C. attracted D. instructed
20.A. learn B. agree C. refuse D. choose
—How come Tom picked a quarrel with his wife?
—________? We also have the occasional argument.
A. What’s on B. How’s that
C. Who doesn’t D. Why not
Learning from ________ mistakes can help us keep conscious and avoid repeating them in the days to come.
A. previous B. curious C. obvious D. ridiculous
