Climate and Country Wealth
Why are some countries stupendously rich and others horrendously poor? Social theorists have been captivated by this question since the late 18th century, when Scottish economist Adam Smith argued in his magisterial work The Wealth of Nations that the best prescription for prosperity is a free-market economy in which the government allows businesses substantial freedom to pursue profits. Smith, however, made a second notable hypothesis: that the physical geography of a region can influence its economic performance. He contended that the economies of coastal regions, with their easy access to sea trade, usually outperform the economies of inland areas.
Coastal regions and those near navigable waterways are indeed far richer and more densely settled than interior regions, just as Smith predicted. Moreover, an area's climate can also affect its economic development. Nations in tropical climate zones generally face higher rates of infectious disease and lower agricultural productivity (especially for staple foods) than do nations in temperate zones. Similar burdens apply to the desert zones. The very poorest regions in the world are those saddled with both handicaps: distance from sea trade and a tropical or desert ecology. The basic lessons of geography are worth repeating, because most economists have ignored them. In the past decade the vast majority of papers on economic development have neglected even the most obvious geographical realities.
The best single indicator of prosperity is gross national product (GNP) per capita – the total value of a country's economic output, divided by its population. A map showing
the world distribution of GNP per capita immediately reveals the vast gap between rich and poor nations. The great majority of the poorest countries lie in the
geographical tropics. In contrast, most of the richest countries lie in the temperate zones. Among the 28 economies categorized as high income by the World Bank, only
Hong Kong, Singapore and part of T aiwan are in the tropical zone, representing a
mere 2 percent of the combined population of the high-income regions. Almost all the temperate-zone countries have either high-income economies (as in the cases of North America, western Europe, Korea and Japan) or middle-income economies (as in the
cases of eastern Europe, the former Soviet Union and China). In addition, there is a strong temperate-tropical divide within countries that straddle both types of climates. Most of Brazil, for example, lies within the tropical zone, but the richest part of the nation – the southernmost states –is in the temperate zone.
There are two major ways in which a region’s climate affects economic development. First, it affects the prevalence of disease. Many kinds of infectious diseases are
endemic to the tropical and subtropical zones. This tends to be true of diseases in
which the pathogen spends part of its life cycle outside the human host: for instance, malaria (carried by mosquitoes) and helminthic infections (caused by parasitic
worms). Although epidemics of malaria have occurred sporadically as far north as
Boston in the past century, the disease has never gained a lasting foothold in the temperate zones, because the cold winters naturally control the mosquito-based
transmission of the disease. Winter could thus be considered the world's most
effective public health intervention. It is much more difficult to control malaria in
tropical regions, where transmission takes place year-round and affects a large part of the population.
According to the World Health Organization, 300 million to 500 million new cases of malaria occur every year, almost entirely concentrated in the tropics. Widespread
illness and early deaths obviously hold back a nation's economic performance by significantly reducing worker productivity. But there are also long-term effects that may be amplified over time through various social feedbacks. A high incidence of disease can alter the age structure of a country's population. Societies with high levels
of child mortality tend to have high levels of fertility: mothers bear many children to guarantee that at least some will survive to adulthood. Young children will therefore constitute a large proportion of that country's population. With so many children, poor families cannot invest much in each child's education. High fertility also constrains the role of women in society, because child rearing takes up so much of their adult lives.
Moreover, temperature affects agricultural productivity. Of the major food grains – wheat, maize and rice – wheat grows only in temperate climates, and maize and rice crops are generally more productive in temperate and subtropical climates than in
tropical zones. On average, a hectare of land in the tropics yields 2.3 metric tons of maize, whereas a hectare in the temperate zone yields 6.4 tons. Farming in tropical rain-forest environments is hampered by the fragility of the soil: high temperatures mineralize the organic materials, and the intense rainfall leaches them out of the soil. In tropical environments that have wet and dry seasons–such as the African
savanna–farmers must contend with the rapid loss of soil moisture resulting from high temperatures, the great variability of precipitation, and the ever present risk of drought. Moreover, tropical environments are plagued with diverse infestations of pests and parasites that can devastate both crops and livestock.
Moderate advantages or disadvantages in geography can lead to big differences in
long-term economic performance. Favorable agricultural or health conditions may
boost per capita income in temperate-zone nations and hence increase the size of their economies. The resulting inventions further raise economic output, spurring yet more inventive activity. The moderate geographical advantage is thus amplified through innovation. In contrast, the low food output per farm worker in tropical regions tends to diminish the size of cities. With a smaller proportion of the population in urban
areas, the rate of technological advance is usually slower. The tropical regions
therefore remain more rural than the temperate regions, with most of their economic activity
concentrated in low-technology agriculture rather than in high-technology
manufacturing and services.
Geographical factors, however, are only part of the story. Social and economic institutions are critical to long-term economic performance. It is particularly instructive to compare the post-World War II performance of socialist and free-market economies in neighboring countries that share the same geographical characteristics: North and South Korea, East and West Germany, the Czech Republic and Austria, and Estonia and Finland. In each case we find that free-market
institutions vastly outperformed their counterparts.
If these findings are true, the policy implications are significant. Aid programs for developing countries will have to be revamped to specifically address the problems imposed by climate and geography. In particular, new strategies have to be formulated that would help nations in tropical zones raise their agricultural productivity and reduce the prevalence of diseases such as malaria.
While fatigue, drowsiness or boredom easily bring on yawns, scientists are discovering there's more to yawning than most people think. Not much is known about why we yawn or if it serves any useful function, and very little research has been done on the subject. However, there are several theories about why we yawn. Here are the four most common:
The physiological theory: Our bodies induce yawning to draw in more oxygen or remove a buildup of carbon dioxide. This theory helps explain why we yawn in groups. Larger groups produce more carbon dioxide, which means our bodies would act to draw in more oxygen and get rid of the excess carbon dioxide. However, if our bodies make us yawn to draw in needed oxygen, wouldn't we yawn during exercise? Robert Provine, a developmental neuroscientist at the University of Maryland, Baltimore County and a leading expert on yawning, has tested this theory: Giving people additional oxygen didn't decrease yawning, and decreasing the
amount of carbon dioxide in a subject's environment also didn't prevent yawning.
The evolution theory: Some think that yawning began with our ancestors, who used yawning to show their teeth and intimidate others. An offshoot of this theory is the idea that yawning developed from early man as a signal for us to change activities. Another speculated reason for yawning is the desire to stretch one's muscles. Yawns are often accompanied by the urge to stretch. Prey animals must be ready to physically exert themselves at any given moment. There have been studies that suggest yawning, especially psychological "contagious" yawning, may have developed as a way of keeping a group of animals alert. If an animal is drowsy or bored, it may not be as alert as it should to be prepared to spring into action. Therefore, the "contagious" yawn could be an instinctual reaction to a signal from one member of the "herd" reminding the others to stay alert. Nervousness has also been suggested as a possible reason. Nervousness often indicates the perception of an impending need for action. Anecdotal evidence suggests that yawning helps increase the state of alertness of a person. Paratroopers have been noted to yawn in the moments before they exit the aircraft.
The brain-cooling theory: A more recent theory proposed by researchers is that since people yawn more in situations where their brains are likely to be warmer -- tested by having some subjects breathe through their noses or press hot or cold packs to their foreheads -- it's a way to cool down their brains. In 2007, researchers, including a professor of psychology, from the University of Albany proposed that yawning may be a means to keep the brain cool. Mammalian brains operate best within a narrow temperature range. In two experiments, they demonstrated that both subjects with cold packs attached to their foreheads and subjects asked to breathe strictly nasally exhibited reduced contagious yawning when watching videos of people yawning.
A similar recent hypothesis is that yawning is used for regulation of body temperature. Similarly, a study by Jared Guttmann at Worcester Polytechnic Institute found that when a subject wearing earplugs yawned, a breeze is heard caused by the flux of the air moving between the subject's ear and the environment. Researcher Guttmann determined that a
yawn causes one of three possible situations to occur: the brain cools down due to an influx or outflux of oxygen, the pressure in the brain is reduced by an outflux of oxygen, or the pressure of the brain is increased by an influx of air caused by increased cranial space. What does it matter if our brains are cold or hot? Cool brains can think more clearly; hence, yawning might have developed to keep us alert.
Interestingly, while all vertebrates (including fish) yawn, only humans, chimps and possibly dogs find yawns contagious. And people don't find them contagious until they're about 4 years old. Recent studies show contagious yawning may be linked to one's capacity for empathy. In one study, autistic and non-autistic children were shown videos of people yawning and people simply moving their mouths. Both groups of kids yawned the same amount when viewing the video of people moving their mouths. But the non-autistic kids yawned much more frequently than those with autism when watching people really yawning.
Since autism is a disorder that affects a person's social interaction skills, including the ability to empathize with others, the autistic kids' lack of yawning when watching others do so could indicate they're less empathetic. The study also found the more severe a child's autism, the less likely he or she was to yawn. On a positive note, someday doctors may be able to diagnose cognitive disabilities in young children more easily by seeing whether or not they can catch a yawn from other.
So even though we still don't know for sure why we yawn, we do know lots of interesting things about yawning: you start yawning in utero; you yawn when you're aroused; more than half of you will yawn if you see someone else yawn; and reading about yawning makes you yawn.
The soviet calendar
There are no fortresses that Bolsheviks cannot storm’. With these words, Stalin expressed the dynamic self-confidence of the Soviet Union’s Five Year Plan: weak and backward Russia was to turn overnight into a powerful modern industrial country. Unlimited enthusiasm was the mood of the day, with the Communists believing that iron will and hard-working manpower alone would bring about a new world. Enthusiasm spread to Time itself, in the desire to make the state a huge efficient machine, where not a moment would be wasted, especially in the workplace. Lenin had already been intrigued by the ideas of the American Frederick Winslow T aylor (1856-1915), whose time-motion studies had discovered ways of stream-lining effort so that every worker could produce the maximum. The Bolsheviks were also great admirers of Henry Ford’s assembly line mass production and of his Fordson tractors that were imported by the thousands. The engineers who came with them to train their users helped spread what became a real cult of Ford. Emulating and surpassing such capitalist models formed part of
the training of the new Soviet Man, a heroic figure whose unlimited capacity for work would benefit everyone in the dynamic new society. All this culminated in the Plan, which has been characterized as the triumph of the machine, where workers would become supremely efficient robot-like creatures.
Yet this was Communism whose goals had always included improving the lives of the proletariat. One major step in that direction was the sudden announcement in 1927 that reduced the working day from eight to seven hours. In January 1929, all industries were ordered adopt the shorter day by the end of the Plan. Workers were also to have an extra hour off on the eve of Sundays and holidays. Typically though, the state took away more than it gave, for this was part of a scheme to increase production by establishing a three-shift system. That meant that the factories were open day and night and that many had to work at highly undesirable hours.
Hardly had that policy been announced, though, than Yuri Larin, who had been a close associate of Lenin and architect of his radical economic policy, came up with an idea for even greater efficiency. Workers were free and plants were closed on Sundays. Why not abolish that wasted day by instituting a continuous work week so that the machines could operate to their full capacity every day of the week? When Larin presented his idea to the Congress of Soviets in May 1929, no one paid much attention. Soon after, though, he got the ear of Stalin, who approved. Suddenly, in June, the Soviet press was filled with articles praising the new scheme. In August, the Council of Peoples’ Commissars ordered the continuous work week brought into immediate effect, during the height of enthusiasm for the Plan, whose goals the new schedule seemed guaranteed to forward.
The idea seemed simple enough, but turned out to be very complicated in practice. Obviously, the workers couldn’t be made to work seven days a week, nor should their total work hours be increased. The solution was ingenious: a new five-day week would have the workers on the job for four days, with the fifth day free; holidays would be reduced from ten to five, and the extra hour off on the eve of rest days would be abolished. Staggering the rest-days between groups of workers meant that each worker would spend the same number of hours
on the job, but the factories would be working a full 360 days a year instead of 300. The 360 divided neatly into 72 five-day weeks. Workers in each establishment (at first factories, then stores and offices) were divided into five groups, each assigned a colour which appeared on the new Uninterrupted Work Week calendars distributed all over the country. Colour-coding was a valuable mnemonic device, since workers might have trouble remembering what their day off was going to be, for it would change every week. A glance at the colour on the calendar would reveal the free day, and allow workers to plan their activities.
Official propaganda touted the material and cultural benefits of the new scheme. Workers would get more rest; production and employment would increase (for more workers would be needed to keep the factories running continuously); the standard of living would improve. Leisure time would be more rationally employed, for cultural activities (theatre, clubs, sports) would no longer have to be crammed into a weekend, but could flourish every day, with their facilities far less crowded. Shopping would be easier for the same reasons. Ignorance and
superstition, as represented by organized religion, would suffer a mortal blow, since 80 per cent of the workers would be on the job on any given Sunday. The only objection concerned the family, where normally more than one member was working: well, the Soviets insisted, the narrow family was far less important than the vast common good and beside, arrangements could be made for husband and wife to share a common schedule.
The continuous work week, hailed as a Utopia where Time itself was conquered and the sluggish Sunday abolished forever, spread like an epidemic. According to official figures 63 per cent of industrial workers were so employed by April 1930; in June, all industry was ordered to convert during the next year. The fad reached its peak in October when it affected 73 per cent of workers. In fact, many managers simply claimed that their factories had gone over to the new week, without actually applying it. Conforming to the demands of the Plan was important; practical matters could wait. By then, though, problems were becoming obvious. Most serious (though never officially admitted), the workers hated it. Coordination of family schedules was virtually impossible and usually ignored, so husbands and wives only saw each other before or after work; rest days were empty without any loved ones to share them - even friends were likely to be on a different schedule. Confusion reigned: the new plan was introduced haphazardly, with some factories operating five-, six- and seven-day weeks at the same time, and the workers often not getting their rest days at all.
The soviet government might not have ignored all that depending on public approval, but the new week was far from having the vaunted effect on production. With the complicated rotation system, the work teams necessarily found themselves doing different kinds of work in successive weeks. Machines, no longer consistently in the hands of people who knew how to tend them, were often poorly maintained or even broken. As a result, the new week started to lose ground. Stalin’s speech in June 1931, which criticized the “depersonalized labor” its too hasty application had brought, marked the beginning of the end. In November, the government ordered the widespread adoption of the six-day week, which had its own calendar, with regular breaks on the 6th, 12th, 18th, 24th, and 30th, with Sunday usually as a working day. By July 1935 only 26 per cent of workers still followed the continuous schedule, and the six-day week was soon on its way out. Finally, in 1940, as part of the general
reversion to more traditional methods, both the continuous five-day week and the novel six-day week were abandoned, and Sunday returned as the universal day of rest. A bold but typically ill-conceived experiment was at an end.
Ants and brain's neurons
An individual ant is not very bright, but ants in a colony, operating as a collective, do remarkable things. A single neuron in the human brain can respond only to what the neurons connected to it are doing, but all of them together can be Immanuel Kant. That resemblance is why Deborah M. Gordon, StanfordUniversity assistant professor of biological sciences, studies ants. "I'm interested in the kind of system where simple units together do behave in complicated ways," she said.
No one gives orders in an ant colony, yet each ant decides what to do next. For instance, an ant may have several job descriptions. When the colony discovers a new source of food, an ant doing housekeeping duty may suddenly become a forager. Or if the colony's territory size expands or contracts, patroller ants change the shape of their reconnaissance pattern to conform to the new realities. Since no one is in charge of an ant colony - including the misnamed "queen," which is simply a breeder - how does each ant decide what to do?
This kind of undirected behavior is not unique to ants, Gordon said. How do birds flying in a flock know when to make a collective right turn? All anchovies and other schooling fish seem to turn in unison, yet no one fish is the leader. Gordon studies harvester ants in Arizona and, both in the field and in her lab, the so-called Argentine ants that are ubiquitous to coastal California. Argentine ants came to Louisiana in a sugar shipment in 1908. They were driven out of the Gulf states by the fire ant and invaded California, where they have displaced most of the native ant species. One of the things Gordon is studying is how they did so. No one has ever seen an ant war involving the Argentine species and the native species, so it's not clear whether they are quietly aggressive or just find ways of taking over food resources and territory.
The Argentine ants in her lab also are being studied to help her understand how they change behavior as the size of the space they are exploring varies. "The ants are good at finding new places to live in and good at finding food," Gordon said. "We're interested in finding out how they do it." Her ants are confined by Plexiglas walls and a nasty glue-like substance along the tops of the boards that keeps the ants inside. She moves the walls in and out to change the arena and videotapes the ants' movements. A computer tracks each ant from its image on the tape and reads its position so she has a diagram of the ants' activities.
The motions of the ants confirm the existence of a collective. "A colony is analogous to a brain where there are lots of neurons, each of which can only do something very simple, but together the whole brain can think. None of the neurons can think ant, but the brain can think ant, though nothing in the brain told that neuron to think ant." For instance, ants scout for food in a precise pattern. What happens when that pattern no longer fits the circumstances, such as when Gordon moves the walls? "Ants communicate by chemicals," she said. "That's how they mostly perceive the world; they don't see very well. They use their antennae to smell.
So to smell something, they have to get very close to it. "The best possible way for ants to
find everything - if you think of the colony as an individual that is trying to do this - is to have an ant everywhere all the time, because if it doesn't happen close to an ant, they're not going to know about it. Of course, there are not enough ants in the colony to do that, so somehow the ants have to move around in a pattern that allows them to cover space efficiently."
Keeping in mind that no one is in charge of a colony and that there is no central plan, how do the ants adjust their reconnaissance if their territory expands or shrinks? "No ant told them, 'OK, guys, if the arena is 20 by 20. . . .' Somehow there has to be some rule that individual ants use in deciding to change the shape of their paths so they cover the areas effectively. I think that that rule is the rate in which they bump into each other." The more crowded they are, the more often each ant will bump into another ant. If the area of their territory is expanded, the frequency of contact decreases. Perhaps, Gordon thinks, each ant has a threshold for normality and adjusts its path shape depending on how often the number of encounters exceeds or falls short of that threshold.
If the territory shrinks, the number of contacts increases and the ant alters its search pattern. If it expands, contact decreases and it alters the pattern a different way. In the Arizona harvester ants, Gordon studies tasks besides patrolling. Each ant has a job. "I divide the tasks into four: foraging, nest maintenance, midden [piling refuse, including husks of seeds] and patrolling - patrollers are the ones that come out first in the morning and look for food. The foragers go where the patrollers find food. "The colony has about eight different foraging paths. Every day it uses several of them. The patrollers go out first on the trails and they attract each other when they find food. By the end of an hour's patrolling, most patrollers are on just a few trails. All the foragers have to do is go where there are the most patrollers."
Each ant has its prescribed task, but the ants can switch tasks if the collective needs it. An ant on housekeeping duty will decide to forage. No one told it to do so and Gordon and other entomologists don't know how that happens. "No ant can possibly know how much food everybody is collecting, how many foragers are needed," she said. "An ant has to have very simple rules that tell it, 'OK, switch and start foraging.' But an ant can't assess globally how much food the colony needs. "I've done perturbation experiments in which I marked ants according to what task they're doing on a given day. The ants that were foraging for food were green, those that were cleaning the nest were blue and so on. Then I created some new situation in the environment; for example, I create a mess that the nest maintenance workers have to clean up or I'll put out extra food that attracts more foragers. "It turns out that ants that were marked doing a certain task one day switch to do a different task when conditions change." Of about 8,000 species of ants, only about 10 percent have been studied thus far. "It's hard to generalize anything about the behavior of ants," Gordon said. "Most of what we know about ants is true of a very, very small number of species compared to the number of species out there."
A facial expression is one or more motions or positions of the muscles in the skin. These movements convey the emotional state of the individual to observers. Facial expressions are a form of nonverbal communication. They are a primary means of conveying social information among humans, but also occur in most other mammals and some other animal species.Fical expressions and their significance in the perceiver can, to some extent, vary between cultures.
Humans can adopt a facial expression to read as a voluntary action. However, because expressions are closely tied to emotion, they are more often involuntary. It can be nearly impossible to avoid expressions for certain emotions, even when it would be strongly desirable to do so; a person who is trying to avoid insulting an individual he or she finds highly unattractive might nevertheless show a brief expression of disgust before being able to reassume a neutral expression. Microexpressions are one example of this phenomenon. The close link between emotion and expression can also work in the other direction; it has been observed that voluntarily assuming an expression can actually cause the associated emotion.
Some expressions can be accurately interpreted even between members of different species- anger and extreme contentment being the primary examples. Others, however, are difficult to interpret even in familiar individuals. For instance, disgust and fear can be tough to tell apart.
Because faces have only a limited range of movement, expressions rely upon fairly minuscule differences in the proportion and relative position of facial features, and reading them requires considerable sensitivity to same. Some faces are often falsely read as expressing some emotion, even when they are neutral, because their proportions naturally resemble those another face would temporarily assume when emoting. Also, a person's eyes reveal much about how they are feeling, or what they are thinking. Blink rate can reveal how nervous or at ease a person may be. Research by Boston College professor Joe Tecce suggests that stress levels are revealed by blink rates. He supports his data with statistics on the relation between the blink rates of presidential candidates and their success in their races. Tecce claims that the faster blinker in the presidential debates has lost every election since 1980. Though Tecce's data is interesting, it is important to recognize that non-verbal communication is multi-channeled, and focusing on only one aspect is reckless. Nervousness can also be measured by examining each candidates' perspiration, eye contact and stiffness.
As Charles Darwin noted in his book The Expression of the Emotions in Man and Animals:the young and the old people of widely different races, both with man and animals, express the same state of mind by the same movements. Still, up to the mid-20th century most anthropologists believed that facial expressions were entirely learned and could therefore differ among cultures. Studies conducted in the 1960s by Paul Ekman eventually supported Darwin's belief to a large degree.
Ekman's work on facial expressions had its starting point in the work of psychologist Silvan Tomkins. Ekman showed that contrary to the belief of some anthropologists including Margaret Mead, facial expressions of emotion are not culturally determined, but universal across human cultures.
The South Fore people of New Guinea were chosen as subjects for one such survey. The study consisted of 189 adults and 130 children from among a very isolated population, as well as twenty three members of the culture who lived a less isolated lifestyle as a control group. Participants were told a story that described one particular emotion; they were then shown three pictures (two for children) of facial expressions and asked to match the picture which expressed the story's emotion.
While the isolated South Fore people could identify emotions with the same accuracy as the non-isolated control group, problems associated with the study include the fact that both fear
and surprise were constantly misidentified. The study concluded that certain facial expressions correspond to particular emotions, regardless of cultural background, and regardless of whether or not the culture has been isolated or exposed to the mainstream.
Expressions Ekman found to be universal included those indicating anger, disgust, fear, joy, sadness, and surprise (note that none of these emotions has a definitive social component, such as shame, pride, or schadenfreude). Findings on contempt (which is social) are less clear, though there is at least some preliminary evidence that this emotion and its expression are universally recognized.
Insects and inspired artificial robot
The creation of artificial devices with life-like characteristics has been pursued for over 2000 years, beginning, as did so many things in our modern world, in Ancient Greece. For example, among the inventions of Hero of Alexandria were a windmill-operated pipe organ and a mechanical theatrical play.
With the rise of cybernetic approaches in the late 1940s and early 1950s, a wide variety of electromechanical machines designed to mimic biological processes and systems were constructed. Perhaps the best-known and most directly relevant to biorobotics is W. Gray Walter's robotic "tortoises" Elsie and Elmer. Walter was a physiologist who made important early contributions to electroencephalography and clinical neurophysiology. His tortoises were small mobile robots covered by a hard shell. The robots were driven by steerable motorized wheels and possessed a headlight, a light sensor, and a touch sensor that
responded when the shell was hit. Their behavior was controlled by electronic circuit analogues of neural circuits. The behavioral repertoire of the tortoises included exploration, both positive and negative phototropisms, and obstacle avoidance. The activation of these different behaviors in interaction with the robots' environment could produce a variety of behavioral sequences. Although originally designed to explore Walter's theories of brain function, the tortoises became objects of popular fascination in much the same way that ancient automata did.
The seeds of the modern renaissance of biorobotics were sown from the mid 1980s to the mid 1990s. A key event in this resurgence was Rodney Brooks' work on behavior-based robots. Although not as directly based on biology as later work would be, Brooks argued that nontrivial and flexible behavior in a robot could be generated by the interaction between simple control machinery and its environment, demonstrating his point with robots accomplishing such tasks as insect-like walking. Another important milestone was Raibert's work on hopping and legged robots, which emphasized the central role of energetics in the dynamic balance and locomotion of animals. Arkin , building on earlier work by Michael Arbib, developed a control architecture for reactive robots based on schema theory. Based on studies of serpentine motion, Hirose developed a number of snake-like locomotors and manipulators. In the early 1990s, Beer, Quinn, Chiel & Ritzmann developed a series of hexapod robots based directly on the body morphology and neural control of cockroach and stick insect walking (the latter, like many hexpod robots, based on the work of biologist Holk Cruse). In addition, Triantafyllou & Triantafyllou built a series of very efficient swimming robots based on studies of the hydrodynamics of fish swimming. Early biorobotic work on the sensory side includes Franceshini's robotic compound eye based on studies of insect eyes and motion-sensitive neurons in the fly, Webb's robotic model of cricket phonotaxis, Grasso et al's robotic model of lobster chemical orientation strategies, and Sahabot, whose navigation by polarized light compass was inspired by studies of homing behavior in the desert ant. An early example of robots whose control was based on theories of human brain function is given by the work of Edelman et al.
There has been an explosion of work in biorobotics in recent years, with robotic vocal tracts, jaws, retinas, expressive faces, hands, arms, legs, etc. deployed on robotic worms, snakes, ants, flies, crickets, cockroaches, walking stick insects, dinosaurs, bats, lobsters, tuna, pickeral, turkeys, apes and humanoids. In addition, there is closely related work on swarm robotics, developmental robotics, and evolutionary robotics. Thus, no brief introduction could possibly do justice to the range of work currently being undertaken.
A recent example of biologically-inspired robotics is Spenko et al's work on a hexapedal robotic climber called RiSE which, like a number of biologically-inspired legged robots, is based in part on work by the biologist Robert Full. In order to grip a vertical surface, this robot combines both bonding mechanisms inspired by the structure of gecko feet and interlocking mechanisms inspired by the structure of insect spines and claws. In addition, its design is based on a set of principles that have been found to be common to many climbing animals: a sprawled posture keeps the body close to the surface so as to reduce the pitch-back
moment; front limbs pull inward and rear limbs push outward so as to counteract the
pitch-back moment; a long body reduces the pull-in force required of the front limbs; lateral forces act inward toward the central axis of the body; compliant legs, ankles and toes so as to distribute contact forces. Each of the six legs of RiSE have two degrees of freedom and the robot also possesses a static tail that presses against the surface to reduce the pull-in forces required of the front legs. The robot uses a wave gait in which only one leg at a time is lifted from the surface. In addition to an open-loop gait generator, RiSE utilizes a variety of feedback controllers, including traction force control, normal force control and gait regulation. In addition, the robot has a pawing behavior that allows a foot that fails to grasp on initial contact to reestablish a grip on the climbing surface. Spenko et al. have demonstrated that RiSE is able to traverse a variety of horizontal and vertical surfaces, including climbing trees and brick or cinder block walls.
A powerful example of biorobotic modeling is provided by the aerodynamics of insect flight. Although quasi-steady-state aerodynamical analyses of the sort used to understand aircraft have been successfully applied to larger animals, they have not been very successful for explaining the generation of lift in small flying insects due to the tiny wingspans, relatively slow flight speeds and extremely fast wing movements involved. However, a recent biorobotic model by Dickinson and colleagues has begun to shed considerable light on the unsteady aerodynamics insect flight. Because of the delicate size and high speed of insect wings, direct measurement of the forces involved is extremely difficult. For this reason, a robotic model with a 60 cm wingspan was used to explore the non-steady-state airflow during hovering by the fruit fly Drosophila melanogaster. In order to reproduce the Reynolds number (ratio of inertial to viscous forces) relevant to small insects flying in air, their model was submerged in mineral oil and scaled both in space and time. Force sensors at the base of one wing allowed direct measurement of the forces produced and illumination of air bubbles in the tank allowed direct observation of the fluid flow around the robotic wings. Dickinson and colleagues found that three major mechanisms contributed to lift generation in the model. First, vortices formed at the leading edge of the wing produce lift during much of the power stroke. Second, additional lift is produced by circulation of air around the wings due to rapid rotation at the beginning and end of each stroke. Third, further forces are produced at the
start of each upstroke and downstroke due to collisions of the wings with the swirling wake produced by the previous stroke, a mechanism termed wake capture. Due to the sensitivity of the latter two mechanisms to the timing of wing rotation, the model suggests that the control of small details of wing motion can be used in steering flight.
Norse mythology tells of the dwarf Otr habitually taking the form of an otter. In some Native American cultures, otters are considered totem animals. The time of year associated with this is also associated with the Aquarius zodiac house, which is traditionally observed January 20-February 18. Indeed, inhabiting five of the continents of the world, otters are truly amazing mammals. Otters are unique in many ways. For instance, otters are the only marine mammals to have fur instead of blubber. There are 13 species of otters alive today. There used to be fourteen, but the fourteenth otter, Maxwell’s otter, is presumed extinct due to draining of their waters to perform genocide in Iraq. Otters are very smart; they are one of only a handful of tool using mammals. Sea Otters use rocks to pry abalone off rocks and to break open shells.
Otters have a dense layer of very soft underfur (almost half a million hairs per square inch of skin) which, protected by their outer layer of long guard hairs, keeps them dry under water
and traps a layer of air to keep them warm. All otters have long, slim, streamlined bodies of extraordinary grace and flexibility, and short limbs; in most cases the paws are webbed. Most have sharp claws to grasp prey but the Short-clawed Otter of southern Asia has just vestigal claws, and two closely related species of African otter have no claws at all: these species live in the often muddy rivers of Africa and Asia and locate their prey by touch.
Fish is the primary item in the diet of most otters, supplemented by frogs, crayfish, and crabs; some have become expert at opening shellfish, and others will take any small mammals or birds that happen to be available. To survive in the cold waters where many otters live, the specialised fur is not enough: otters have very high metabolic rates and burn up energy at a profligate pace: Eurasian Otters, for example, must eat 15% of their body weight a day; Sea Otters, 20 to 25%, depending on the temperature. In consequence, otters are very vulnerable to prey depletion: in water as warm as 10°C an otter needs to catch 100 g of fish per hour: less than that and it cannot survive. Most species hunt for 3 to 5 hours a day; nursing mothers up to 8 hours a day.
The North American River Otter (Lutra canadensis) was one of the major animals hunted and trapped for fur in North America after contact with Europeans. They are playful and active, making them a popular exhibit in zoos and aquaria, but unwelcome on agricultural land because they alter river banks for access, sliding, and defense. River otters eat a variety of fish and shellfish, as well as small land mammals and birds. They are 3-4 feet in length and weigh from 10-30 pounds. They were once found all over North America, but are rare or extinct in most places, although flourishing in some locations.
Sea otters (Enhydra lutris) live along the Pacific coast of North America. Their historic range included shallow waters of the Bering Strait and Kamchatka, and as far south as Japan. Sea otters have about 26,000 to 165,000 strands of hair per square centimetre of skin, a rich fur for which humans hunted them almost to extinction. By the time the 1911 Fur Seal Treaty gave them protection, so few sea otters remained that the fur trade had become unprofitable. Sea otters eat shellfish and other invertebrates (especially clams, abalone, and sea urchins), frequently using rocks as crude tools to smash open shells. They grow to 1.0 to 1.5 metres
(2.5 to 5 ft) in length and weigh 30 kilograms (65 lb). Although once near extinction, they have begun to spread again, from remnant populations in California and Alaska.
Otters also inhabit Europe, and its range also extends across most of Asia and parts of North Africa. In the British Isles, they occurred commonly as recently as the 1950s, but became rare in many areas due to the use of chlorinated hydrocarbon pesticides and as a result of habitat loss and water pollution (they remained relatively common in parts of Scotland and Ireland). Population levels attained a low point in the 1980s, but are now recovering strongly. The UK Biodiversity Action Plan envisages the re-establishment of otters by 2010 in all the UK rivers and coastal areas they inhabited in 1960. Roadkill deaths have become one of the significant threats to the success of their re-establishment.
The European Otter has received full legal protection in England and Wales since 1978. It is included in Schedule 5 of the Wildlife and Countryside Act 1981, making it an offence to kill, injure or take a wild otter without a licence; to intentionally damage, destroy or obstruct a holt; or to disturb an otter in its resting place. With the aid of a number of initiatives, by 1999 estimated numbers indicated a recovery to under 1000 animals. The UK Biodiversity Action Plan envisages the re-establishment of otters by 2010 in all the UK rivers and coastal areas that they inhabited in 1960. Roadkill deaths have become one of the significant threats to the success of their re-establishment.
Rapid, Urban, and Flexible
The car is so popular that it is about to strangle itself in success. On the other hand, traditional bus/train transit systems are so unattractive that they will never be able to become a real alternative to the car in a society where there is freedom of choice. Something new has to be invented. Something which is as flexible as the car, but as efficient as the train regarding capacity and environmental impact. A Dual Mode system is able to offer this new combination.
Modern cities are very low density. People prefer to have space around them. It is good for the children and you have more privacy than in highrise buildings. The consequence is, that travel patterns are very diffuse both in time and in space. People are traveling from everywhere to everywhere and at the time they choose to travel. This makes it extremely difficult to transport people with traditional transit. Normally people are not willing to walk more than 400 m to a station, so a Light Rail system will only appeal to a minor part of the travelors. In the figure the grey lines are the demands, the red lines (10%) are the demands that can be met by the Light Rail system. A Dual Mode system like RUF is able to cover widespread cities. For that reason it is a better alternative to the car than traditional transit. The vehicles drive manually a few km on ordinary roads in order to get to the rail system. The driver programmes the ruf to know its destination and this information is transferred to the system when the vehicle gets near to the monorail. The system guides the vehicle to enter the guideway without waiting and at 30 km/h. From there on the driver can relax until he get close to his destination where he takes over control again and drives manually to his destination. The main part of the trip is automated and the system knows when to turn right or left and when to get off. The automated part is very safe and energy efficient. The travel speed is typically 120 km/h on average. Travel times are short and predictable.
The RUF system will be implemented as a network of guideways. A typical mesh size will be 5 x 5 km, so a typical commuter will use 3 sections of the rail. At every junction, the speed is reduced to 30 km/h. The top speed between junctions can reach 200 km/h, but typically it will be 150 km/h when the mesh size is 5 x 5 km. The reason for this speed reduction during switching is partly that the the safety has to be extremely high in an automated system, partly that if the speed was any higher, the radius of curvature would be much higher (it goes with the square of the speed). In an existing city it will not be possible to find room for soft curves. At 30 km/h the comfort criteria will allow for a 26 m radius of curvature.
The vehicles in the RUF system are coupled to form trains when they use the guideway. The length of the train depends on the demand. During night everybody will be allowed to travel alone. During rush hour 1 ruf per second can enter the guideway system. This means that a train of 10 rufs can be created in approx. 10 seconds. This train creation can be made before merging onto the main rail. This way a very high capacity can be obtained. Capacity is more than just a number. The quality of capacity depends on the frequency. It is much better to have a capacity of 20,000 passengers per hour per direction with many small units than the same capacity obtained by squeezing people into large trains.
The RUF system can reduce the energy consumption from individual traffic. The main factor is the reduction of air resistance due to close coupling of vehicles. The energy consumption per ruf can be reduced to less than 1/3 at 100 km/h. Since RUF is an electric system, renewable sources can be used without problems. A combination of windmills and a RUF rail could be used over water. Solar cells can also be integrated into the system and ensure completely sustainable transportation.
The RUF system uses the space very efficiently. Only 2.5 x 2.5 m is required for the rail. This means that it will often be possible to place a guideway along existing traffic corridors, so that the ROW can be used more efficiently. A tunnel solution can be created where one tube can contain 3 rails. This means that the cost will be much lower than for a train system requiring
2 tubes. The third rail can be used to supply more capacity for rush hour traffic in one direction or to help in an emergency.
The vehicles in a RUF system "rides" very safely on top of a triangular monorail. This means that derailments are impossible and that the users will feel safe because it is easy to understand that when the rail is actually inside the vehicle it is absolutely stable. The special rail brake ensures that braking power is always available even during bad weather. The brake can squeeze as hard against the rail as required in order to bring the vehicle to a safe stop. If a vehicle has to be evacuated, a walkway between the two rails can be used.
Personal Rapid Transit (PRT) is a beautiful system where small vehicles drive on demand on a guideway system. It is much better than traditional transit. Unfortunately it has never been fully implemented. Part of the reason is, that it is not a Dual Mode system. It cannot leave the guideway. RUF can work as a PRT system where it is relevant (in dense parts of a town), but is also a Dual Mode system. In this respect it can be seen as a PRT+ system. Since RUF also uses the maxi-ruf, it can be considered as a PRT++ system.
It will be impossible to start the RUF system as a system with privately owned rufs from the start. Nobody would invest in a new infrastructure without knowing if anybody would like to buy the vehicles for it. For that reason, it is the intention to start it as a Public Transport system. Since the guideway is very slender and relatively inexpensive, such a system will be less costly than traditional public transport. It would also be a success compared to traditional transit because of the very high level of service offered in RUF.
HOW IQ BECOMES IQ
In 1904 the French minister of education, facing limited resources for schooling, sought a way to separate the unable from the merely lazy. Alfred Binet got the job of devising selection principles and his brilliant solution put a stamp on the study of intelligence and was the forerunner of intelligence tests still used today. He developed a thirty-problem test in 1905, which tapped several abilities related to intellect, such as judgment and reasoning. The test determined a given child's mental age'. The test previously established a norm for children of a given physical age. For example, five-year-olds on average get ten items correct, therefore, a child with a mental age of five should score 10, which would mean that he or she was functioning pretty much as others of that age. The child's mental age was then compared to his physical age.
A large disparity in the wrong direction (e.g., a child of nine with a mental age of four) might
suggest inability rather than laziness and means that he or she was earmarked for special schooling. Binet, however, denied that the test was measuring intelligence and said that its purpose was simply diagnostic, for selection only. This message was however lost and caused many problems and misunderstandings later. Although Binet's test was popular, it was a bit inconvenient to deal with a variety of physical and mental ages. So, in 1912, Wilhelm Stern suggested simplifying this by reducing the two to a single number. He divided the mental age by the physical age and multiplied the result by 100. An average child, irrespective of age, would score 100. a number much lower than 100 would suggest the need for help and one much higher would suggest a child well ahead of his peer.
This measurement is what is now termed the IQ (intelligence quotient) score and it has evolved to be used to show how a person, adult or child, performed in relation to others. The term IQ was coined by Lewis m. Terman, professor of psychology and education of Stanford University, in 1916. He had constructed an enormously influential revision of Binet's test, called the Stanford-Binet test, versions of which are still given extensively. The field studying intelligence and developing tests eventually coalesced into a sub-field of psychology called psychometrics (psycho for ‘mind' and metrics for 'measurements'). The practical side of psychometrics (the development and use of tests) became widespread quite early, by 1917, when Einstein published his grand theory of relativity, mass-scale testing was already in use.
Germany's unrestricted submarine warfare (which led to the sinking of the Lusitania in 1915) provoked the United States to finally enter the first world war in the same year. The military had to build up an army very quickly and it had two million inductees to sort out. Who would become officers and who enlisted men? Psychometricians developed two intelligence tests that helped sort all these people out, at least to some extent. This was the first major use of testing to decide who lived and who died since officers were a lot safer on the battlefield.
The tests themselves were given under horrendously bad conditions and the examiners seemed to lack common sense. A lot of recruits simply had no idea what to do and in several sessions most inductees scored zero! The examiners also came up with the quite astounding
2019年雅思考试巩固模拟试题及答案1 Next Year Marks the EU's 50th Anniversary of the Treaty A. After a period of introversion and stunned self-disbelief, continental European governments will recover their enthusiasm for pan-European institution-building in 2007. Whether the European public will welcome a return to what voters in two countries had rejected so short a time before is another matter. B. There are several reasons for Europe’s recovering self-confidence. For years European economies had been lagging dismally behind America (to say nothing of Asia), but in 2006 the large continental economies had one of their best years for a decade, briefly outstripping America in terms of growth. Since politics often reacts to economic change with a lag, 2006’s improv ement in economic growth will have its impact in 2007, though the recovery may be ebbing by then. C. The coming year also marks a particular point in a political cycle so regular that it almost seems to amount to a natural law. Every four or five years, European countries take a large stride towards further integration by signing a new treaty： the Maastricht treaty in 1992, the Treaty of Amsterdam in 1997, the Treaty of Nice in 2001. And in 2005 they were supposed to ratify a European constitution, laying the ground for yet more integration—until the calm rhythm
Animal’s Self-Medicatin TRUE/NOT GIVEN/FALSE/TRUE pitch/terpenses/alkaloids/detoxity/hooks G/D/E/C Development of Public Management Theory BE/AD/AB/AC/A/B/D/C/B ---------------------------------------------17 Koalas C/C/A/B/A YES/NO/NO/NOT GIVEN/YES/NOT GIVEN/YES A Coastal Archaeology of Britain C/D/A TRUE/FALSE/TRUE/FALSE/NOT GIVEN/TRUE/TRUE/ADF
Communication Styles and Conflict iii/vii/i/iv/ix/viii/v/ii TRUE/FALSE/NOT GIVEN/TRUE/TRUE B Talc Powder Applied on Food and Agricultural Industries B/B/A/A/C/B 20/foam/waste water/harmful/biodegrade/droplet(s)/lamination(packing)/gr ape grower(s) Human Navigation-finding our way B / C / A / C / B / C / D / A / TRUE / NOT GIVEN / TRUE / FALSE / NOT GIVEN Plant Scents B/A/F/C TRUE/NOT GIVEN/TRUE/FALSE B/B/C/D/A
Climate and Country Wealth Why are some countries stupendously rich and others horrendously poor? Social theorists have been captivated by this question since the late 18th century, when Scottish economist Adam Smith argued in his magisterial work The Wealth of Nations that the best prescription for prosperity is a free-market economy in which the government allows businesses substantial freedom to pursue profits. Smith, however, made a second notable hypothesis: that the physical geography of a region can influence its economic performance. He contended that the economies of coastal regions, with their easy access to sea trade, usually outperform the economies of inland areas. Coastal regions and those near navigable waterways are indeed far richer and more densely settled than interior regions, just as Smith predicted. Moreover, an area's climate can also affect its economic development. Nations in tropical climate zones generally face higher rates of infectious disease and lower agricultural productivity (especially for staple foods) than do nations in temperate zones. Similar burdens apply to the desert zones. The very poorest regions in the world are those saddled with both handicaps: distance from sea trade and a tropical or desert ecology. The basic lessons of geography are worth repeating, because most economists have ignored them. In the past decade the vast majority of papers on economic development have neglected even the most obvious geographical realities. The best single indicator of prosperity is gross national product (GNP) per capita – the total value of a country's economic output, divided by its population. A map showing the world distribution of GNP per capita immediately reveals the vast gap between rich and poor nations. The great majority of the poorest countries lie in the geographical tropics. In contrast, most of the richest countries lie in the temperate zones. Among the 28 economies categorized as high income by the World Bank, only Hong Kong, Singapore and part of T aiwan are in the tropical zone, representing a mere 2 percent of the combined population of the high-income regions. Almost all the temperate-zone countries have either high-income economies (as in the cases of North America, western Europe, Korea and Japan) or middle-income economies (as in the cases of eastern Europe, the former Soviet Union and China). In addition, there is a strong temperate-tropical divide within countries that straddle both types of climates. Most of Brazil, for example, lies within the tropical zone, but the richest part of the nation – the southernmost states –is in the temperate zone. There are two major ways in which a region’s climate affects economic development. First, it affects the prevalence of disease. Many kinds of infectious diseases are endemic to the tropical and subtropical zones. This tends to be true of diseases in which the pathogen spends part of its life cycle outside the human host: for instance, malaria (carried by mosquitoes) and helminthic infections (caused by parasitic worms). Although epidemics of malaria have occurred sporadically as far north as Boston in the past century, the disease has never gained a lasting foothold in the temperate zones, because the cold winters naturally control the mosquito-based
Next Year Marks the EU's 50th Anniversary of the Treaty A. After a period of introversion and stunned self-disbelief，continental European governments will recover their enthusiasm for pan-European institution-building in . Whether the European public will welcome a return to what voters in two countries had rejected so short a time before is another matter. B. There are several reasons for Europe’s recovering self-confidence. For years European economies had been lagging dismally behind America (to say nothing of Asia)， but in the large continental economies had one of their best years for a decade， briefly outstripping America in terms of growth. Since politics often reacts to economic change with a lag，’s improvement in economic growth will have its impact in ， though the recovery may be ebbing by then. C. The coming year also marks a particular point in a political cycle so regular that it almost seems to amount to a natural law. Every four or five years， European countries take a large stride towards further integration by signing a new treaty： the Maastricht treaty in 1992， the Treaty of Amsterdam in 1997， the Treaty of Nice in . And in they were supposed to ratify a European constitution， laying the ground for yet more integration—until the calm rhythm was rudely shattered by French and Dutch voters. But the political impetus to sign something every four or five years has only been interrupted，not immobilised， by this setback. D. In the European Union marks the 50th anniversary of another treaty—the Treaty of Rome， its founding charter. Government leaders have already agreed to celebrate it ceremoniously， restating their commitment to “ever closer union” and the basic ideals of European unity. By itself， and in normal circumstances， the EU’s 50th-birthday greeting to itself would be fairly meaningless， a routine expression of European good fellowship. But it does not take a Machiavelli to spot that once governments have signed the declaration (and it seems unlikely anyone would be so uncollegiate as to veto
Time to cool it 1 REFRIGERATORS are the epitome of clunky technology： solid， reliable and just a little bit dull. They have not changed much over the past century， but then they have not needed to. They are based on a robust and effective idea--draw heat from the thing you want to cool by evaporating a liquid next to it， and then dump that heat by pumping the vapour elsewhere and condensing it. This method of pumping heat from one place to another served mankind well when refrigerators' main jobs were preserving food and， as air conditioners， cooling buildings. Today's high-tech world， however， demands high-tech refrigeration. Heat pumps are no longer up to the job. The search is on for something to replace them. 2 One set of candidates are known as paraelectric materials. These act like batteries when they undergo a temperature change： attach electrodes to them and they generate a current. This effect is used in infra-red cameras. An array of tiny pieces of paraelectric material can sense the heat radiated by， for example， a person， and the pattern of the array's electrical outputs can then be used to construct an image. But until recently no one had bothered much with the inverse of this process. That inverse exists， however. Apply an appropriate current to a paraelectric material and it will cool down. 3 Someone who is looking at this inverse effect is Alex Mischenko， of Cambridge University. Using commercially available paraelectric film， he and his colleagues have generated temperature drops five times bigger than any previously recorded. That may be enough to change the phenomenon from a laboratory curiosity to something with commercial applications. 4 As to what those applications might be， Dr Mischenko is still a little hazy. He has， nevertheless， set up a company to pursue them. He foresees putting his discovery to use in more efficient domestic fridges and air conditioners. The real money， though， may be in cooling computers. 5 Gadgets containing microprocessors have been getting hotter for a long time. One consequence of Moore's Law， which describes the doubling of the number of transistors on a chip every 18 months， is that the amount of heat produced doubles as well. In fact， it more than doubles， because besides increasing in number，the components are getting faster. Heat is released every time a logical operation is performed inside a microprocessor， so the faster the processor is， the more heat it generates. Doubling the frequency quadruples the heat output. And the frequency has doubled a lot. The first Pentium chips sold by Dr Moore's company，Intel， in 1993， ran at 60m cycles a second. The Pentium 4--the last "single-core" desktop processor--clocked up 3.2 billion cycles a second. 6 Disposing of this heat is a big obstruction to further miniaturisation and higher speeds. The innards of a desktop computer commonly hit 80℃. At 85℃， they
2019年雅思考试阅读理解模拟练习试题及答案A. When Denis Hennequin took over as the European boss of McDonald’s in January 2004，the world’s biggest restaurant chain was showing signs of recovery in America and Australia，but sales in Europe were sluggish or declining.One exception was France，where Mr Hennequin had done a sterling job as head of the group’s French subsidiary to sell more Big Macs to his compatriots.His task was to replicate this success in all 41 of the European countries where anti- globalisers’favourite enemy operates. B. So far Mr Hennequin is doing https://www.sodocs.net/doc/0411268503.html,st year European sales increased by 5.8%and the number of customers by 3.4%， the best annual results in nearly 15 years.Europe accounted for 36%of the group’s profits and for 28%of its sales.December was an especially good month as customers took to seasonal menu offerings in France and Britain，and to a promotion in Germany based on the game of Monopoly. C Mr Hennequin’s recipe for revival is to be more open about his company’s operations，to be“locally relevant”，and to improve the experience of visiting his 6，400 restaurants.McDonald’s is blamed for making people fat，exploiting workers，treating animals cruelly，polluting the environment and simply for being American.Mr Hennequin says
2019年雅思IELTS考试备考资料模拟试题及答案14 The nervous system of vertebrates is characterized by a hollow, dorsal nerve cord that ends in the head region as an enlargement, the brain. Even in its most primitive form this cord and its attached nerves are the result of evolutionary specialization, and their further evolution from lower to higher vertebrate classes is a process that is far from fully understood. Nevertheless, the basic arrangements are similar in all vertebrates, and the study of lower animals gives insight into the form and structure of the nervous system of higher animals. Moreover, for any species, the study of the embryological development of the nervous system is indispensable for an understanding of adult morphology. In any vertebrate two chief parts of the nervous system may be distinguished. These are the central nervous system (the nerve cord mentions above), consisting of the brain and spinal cord, and the peripheral nervous system, consisting of the cranial, spinal, and peripheral nerves, together with their motor and sensory endings. The term "autonomic nervous system" refers to the parts of the central and peripheral systems that supply and regulate the activity of cardiac muscle, smooth muscle, and many glands. The nervous system is composed of many millions of nerve and glial cells, together with blood vessels and a small amount of connective tissue. The nerve cells, or "neurons", are characterized by many processes and are specialized in that they exhibit to a great degree the phenomena of irritability and conductivity. The glial cells of the central nervous system are supporting cells collectively termed
Section I Words A.Match the words with the same meaning.W rite down the letters on you answer sheet. (1(1’’*6) 1.epidermic 2.motivate 3.assume 4.appealing 5.controversy 6expertise A.skill or knowledge in a particular area B.dispute,argument C.attractive D.an outbreak of a contagious disease that spreads rapidly and widely E.to provide with an incentive;impel . F.to take for granted,suppose B.Fill in the blanks with proper forms of words given in the box,one word can be used more than once.(1(1’’*10) evolve prepare propose minimum peer through cheat weep address exploit except 1.Not surprisingly,his was not well received,even though it seemed to agree with the scientific information available at the time.. 2.The little girl with disappointment when she learned that her favourite Barbie Dolls were sold out. 3.The price is her,she refuses to lower it any further. 4.Apes,monkeys and many other primates have fairly elaborate systems of calls for communicating with other members of their species. 5.Some melodies are quite manipulative,working on our emotions very effectively,and composers have often this to the full. 6.I realized I’d been when I saw the painting on sale for half the price I paid for it. 7.To this problem,Counter Intelligence built a kitchen of its own and started making gagets to fill it with. 8.Most birds don’t have a good sense of smell,but fish-eaters such as petrels and shearwaters are significant. 9.Why bother a clear door,when you can put a camera in the oven to broadcast snapshots of the activities in the oven to a screen in another room? 10.Exploration will allow us to make suitable for dealing with any dangers that we might face,and we may be able to find physical resources such as minerals. SectionⅡ.Translation A.Translate the following sentences into English.(3(3’’*5) 1.Despite the hardship he encountered,Mark never (放弃对知识的追求) 2.由于缺乏对这种病的了解，许多人依然认为HIV受害者都是自作自受。(owing to; ignorance)
2020年11月21日雅思考试真题及答案 雅思线下11月21日已结束，雅思又上热搜，很多小伙伴看到阅读的书剑，内心都一惊。11月难度再次刷新，不知道12月的会不会简单点……那么2020年11月21日雅思考试试题如何呢？我们一起回顾下： 2020年11月21日雅思听力真题及答案SECTION 1 主题：旅游咨询 题型：填空 参考答案： 1. 13 July 2. Temple 3. ferry 4. moderate 5. dancing 6. castle 7. breakfast 8. house 9. Harvey 10. 45 days SECTION 2
主题：交响音乐会介绍 题型：选择+匹配 参考答案： 11. new people 12. who can play violin 13. attend two rehearsals every week 14. play in local area 15. E 16. F 17. A 18. G 19. B 20. H SECTION 3 主题：关于学习的调研网课讨论 题型：选择+匹配 SECTION 4 主题：气候与建筑 题型：填空 参考答案： 31. both in rural areas and in cities 32. received funds of a city bank
33. skyscrapers: lower levels of acid in damaging pollutants 34. in recent years, Alter Project focuses on the buildings made of stone 35. glasses used to reduce pollution in skyscrapers 36. are affected by the increased rainfall 37. humidity affects the constrictions made of wood 38. are worried about the soil that protects the foundation of buildings 39. architects monitor the evidence of the movement of buildings 40. government should make guidelines for architects 2020年11月21日雅思阅读真题及答案Passage 1 主题：新旧公园 题型：匹配+选择 参考答案： 1. A：visibility and accessibility of parks 2. B：park numbers increased 3. C：reasons why park popularity declined 4. D：importance of park design 5. E：different opinions in the park roles 6. F：different functions of parks 7. David 8. James
Selling Digital Music without Copy-protection Makes Sense A. It was uncharacteristically low-key for the industry’s greatest showman. But the essay published this week by Steve Jobs， the boss of Apple，on his firm’s website under the unassuming title “Thoughts on Music” has nonetheless provoked a vigorous debate about the future of digital music，which Apple dominates with its iPod music-player and iTunes music-store. At issue is “digital rights management” (DRM)—the technology guarding downloaded music against theft. Since there is no common standard for DRM， it also has the side-effect that songs purchased for one type of music-player may not work on another. Apple’s DRM system， called FairPlay， is the most widespread. So it came as a surprise when Mr. Jobs called for DRM for digital music to be abolished. B. This is a change of tack for Apple. It has come under fire from European regulators who claim that its refusal to license FairPlay to other firms has “locked in” customers. Since music from the iTunes store cannot be played on non-iPod music-players (at least not without a lot of fiddling)， any iTunes buyer will be deterred from switching to a device made by a rival firm， such as Sony or Microsoft. When French lawmakers drafted a bill last year compelling Apple to open up FairPlay to rivals， the company warned of “state-sponsored piracy”. Only DRM， it implied， could keep the pirates at bay. C. This week Mr. Jobs gave another explanation for his former defence of DRM： the record companies made him do it. They would make their music available to the iTunes store only if Apple agreed to protect it using DRM. They can still withdraw their catalogues if the DRM system is compromised. Apple cannot license FairPlay to others， says Mr Jobs， because it would depend on them to produce security fixes promptly. All DRM does is restrict consumer choice and provide a barrier to entry， says Mr Jobs； without it there would be far more stores and players， and far more innovation. So， he suggests， why not do away with DRM and sell music unprotected？“This is