题目内容

以下各项中,()不是数据报操作的特点。

A. 每个分组自身带有足够的信息,它的传送是被单独处理的
B. 在整个传送过程中,不需建立虚电路
C. 所有分组按顺序到达目的地
D. 网络节点要为每个分组作出路由选择

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3.Born to be Big In 2006 scientists at the Harvard School of Public Health reported that the prevalence of obesity (肥胖) in infants under 6 months had risen 73 percent since 1980. "This epidemic of obese 6 - month - olds," as Robert Lustig of the University of California, San Francisco, calls it, poses a problem for conventional explanations of the fattening of America. "Since they’ re eating only formula (配方奶) or breast milk, and never exactly got a lot of exercise, the obvious explanations for obesity don’t work for babies," he points out. "You have to look beyond the obvious. " The search for the non - obvious has led to an early - life exposure to Paces of chemicals in the environment. Evidence has been steadily accumulating that certain hormone - mimicking pollutants (污染物质), ubiquitous (到处存在的) in the food chain, have two previously effects. They act on genes in the developing fetus (胎儿) and newborn to turn more precursor (前体) cells into fat cells, which stay with you for life. And they may alter metabolic (新陈代谢的) rate, so that the body saves calories rather than burning them. "The evidence now emerging says that being overweight is not just the result of personal choices about what you eat, combined with inactivity," says Retha Newbold of the National Institute of Environmental Health Sciences (NIEHS). " Exposure to environmental chemicals during development may he contributing to the obesity epidemic. "They are not the cause of extra pounds in every person who is overweight but environmental chemicals may well account for a good part of the current epidemic, especially in those under 50. The new thinking about obesity comes at a critical time politically. As the debate over health care shines a light on the country’s unsustainable spending on doctors, hospitals, and drugs, the obese make tempting scapegoats (替罪羊). About 60 percent of Americans are overweight or obese, and their health - care costs are higher: $3,400 in annual spending for a normal- weight adult versus $ 4,870 for an obese adult, mostly due to their higher levels of type 2 diabetes, heart disease, and other conditions. If those outsize costs inspire greater efforts to prevent and treat obesity, fine. But if they lead to demonizing (妖魔化) the obese - caricaturing (画成漫画讽刺) them as lazy pigs raising insurance premiums (保险费) for the rest of us -that’ s a problem, and not only for ethical reasons: it threatens to obscure (使不明显) that one potent cause of weight gain may be largely beyond an individual’s control. There are about 73% more fat infants under 6 months since 1980.

A. Right
B. Wrong
C. Not mentioned

The grid computing is a new (66) technology connecting the distributed and (67) resources to the high-speed network and integrating a super-computer of processing capacity. The significance and architecture of the grid computing is explained. Several kernel technology such as OGSI, resource management, task management, task scheduling, high rate communication and security are described. Aiming at the particularity of the grid computing environment a mechanism similar to the technology of the search engine is designed to registry, discovery and (68) the resources in the grid. The whole model of the resource management is built by connecting task manager in the local resource management system to others with P2P model. The task may migrate among the task managers in order to (69) the load. The task users summit may be executed in relatively tight resource set, which will not only decrease the total communication overheads of the whole task but also (70) the performance of the system. (69)处填()。

A. decrease
B. balance
C. enhance
D. keep

The Anti- Alcohol Campaign Tries in Russia Last week Russian President Dmitry Medvedev kicked off a new anti - alcohol campaign aimed at cutting the nation’s per capita consumption of alcohol by nearly a quarter by 2012. Russians currently drink about 18 liters (19 quarts) a year, more than double the 8 liters (8.4 quarts) deemed safe by the World Health Organization (WHO). With each additional liter, adds the WHO, men can subtract 11 months from their average life expectancy. The latest move consists of three parts: a media campaign, restrictions on beer consumption, and strict penalties for selling to minors. Russian officials plan to set up more than 500 health centers by the end of the year, complete with Soviet - era tactics like drawings of cimlosis (肝硬化) - stricken livers on their walls. Even with such aggressive measures, it’ s hardly the most ambitious campaign Russians has ever launched against drinking. Former leader Mikhail Gorbachev got alcohol sales to decline by 60 percent. Three years ago, a group of young Russians organized a sort of Vigilante (治安维持会成员)vice squad to single out and shame merchants who sold alcohol to minors. Supported by the Moscow city administration, the Solar Circle movement, as they called themselves, held rallies, and slapped leaflets on the shop doors of guilty establishments. They piqued (激起,激发) media interest at first, but the momentum soon fizzled (渐停,夭折). Some critics say that, while admirable: it hardly addresses the biggest culprit of all: vodka. "The main problem is the availability of hard liquor," says Aleksandr Nemtsov, a top Russian expert on alcohol policy. Some 70 percent of alcohol consumption in Russia is of the hard stuff, primarily vodka. One attempt, tried in the mid - 1990s, substituted beer as a less intoxicating non - liquor alternative. Instead, "beer has become a gateway opening the way to alcoholism for teenagers," says Oleg Zykov, a member of the Public Chamber. The earlier people start down that route, the more likely they are to end up grappling with (尽力解决) alcoholism problems later. Still, for now, Russians seem to support the government’ s new approach. As the National Center for the Study of Public Opinion reported last week, 65 percent of the population say they are in favor of the new measures - especially those that restrict alcohol sales to those under 21. (Right now, the drinking age is 18. ) According to the passage, what is the main aim to carry out the anti -alcohol movement

A. To limit the expenditure on drinking.
B. To restraint the development of beverage industry.
C. To lead people to drink less alcohol beverage.
D. To show govemment’ s concern about public healt

Chocolate to Live For! A study published in the Journal of the American Medical Association in 2003 reported that dark chocolate may lower your blood pressure. Researchers at the University of Cologne studied men and women who were recently diagnosed with mild high blood pressure. Half were given 100g (fabout 3.5 ounces) of dark chocolate per day and half were given white chocolate. After only two weeks systolic (收缩的) blood pressure decreased on average by five points and diastolic (以及舒张的) blood pressure by two points in those consuming dark chocolate, but not those consuming white chocolate. In a similar study, researchers from Italy reported in the American Heart Association journal Hypertension that 3.5 ounces of dark chocolate for one week lowered systolic blood pressure by 12 points and diastolic blood pressure by 8.5 points when blood pressure was monitored continuously for 24 hours. Insulin (胰岛素) sensitivity and LDL cholesterol also improved. No benefits were seen with white chocolate. Another study published in the Journal of the American College of Cardiology found that chocolate may help repair damage to smokers’ blood vessels, at least temporarily. why Chocolate increases your body’ s production of nitric oxide (一氧化氮), a powerful substance that causes your blood vessels to relax and dilate. This, in turn, causes an increase in blood flow and a decrease in blood pressure--like opening a water spigot (水龙头). A study published in July in the Journal of the American Medical Association reported that just 30 calories per day of dark chocolate lowered blood pressure and increased nitric oxide production after 18 weeks. Nitric oxide is also stimulated by drugs such as Viagra and Levitra, which increase blood flow to the penis and enhance erections. This may be one of the reasons why chocolate has had a long reputation as an aphrodisiac (壮阳药). Casanova (卡萨诺瓦) is said to have considered it as his "favorite breakfast dish. " Chocolate also contains phenylethylamine (苯乙胺), which research suggests is a stimulant that is released when you’ re interacting with someone intimately. Which of the following statements is true about the subjects in the 2003 study

A. They were all diagnosed with very high blood pressure before they joined the study.
B. They were given 100g of dark chocolate every day for two weeks.
C. Those who had taken dark chocolate had a decrease of systolic blood pressure.
D. All the participants had a decrease of systolic blood pressure and diastolic blood pressur

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