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The author of the passage believes that writers are ambivalent to recognition because it is
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Originally, scientists predicted small asteroids to be hard and rocky, as any loose surface material (called regolith) generated by impacts was expected to escape their weak gravity. Aggregate small bodies were not thought to exist, because the slightest sustained relative motion would cause them to separate. But observations and computer modeling are proving otherwise. Most asteroids larger than a kilometer are now believed to be composites of smaller pieces. Those imaged at high-resolution show evidence for copious regolith despite the weak gravity. Most of them have one or more extraordinarily large craters, some of which are wider than the mean radius of the whole body. Such colossal impacts would not just gouge out a crater-they would break any monolithic body into pieces. In short, asteroids larger than a kilometer across may look like nuggets of hard rock but are more likely to be aggregate assemblages-or even piles of loose rubble so pervasively fragmented that no solid bedrock is left.
The rubble hypothesis, proposed decades ago by scientists, lacked evidence, until the planetologist Shoemaker realized that the huge craters on the asteroid Mathilde and its very low density could only make sense together: a porous body such as a rubble pile can withstand a battering much better than an integral object. It will absorb and dissipate a large fraction of the energy of an impact; the far side might hardly feel a thing. At first, the rubble hypothesis may appear conceptually troublesome. The material strength of an asteroid is nearly zero, and the gravity is so low one is tempted to neglect that too. The truth is neither strength nor gravity can be ignored. Paltry though it may be, gravity binds a rubble pile together. And anybody who builds sandcastles knows that even loose debris can cohere. Oft-ignored details of motion begin to matter: sliding friction, chemical bonding, damping of kinetic energy, etc. We are just beginning to fathom the subtle interplay of these minuscule forces.
The size of an asteroid should determine which force dominates. One indication is the observed pattern of asteroidal rotation rates. Some collisions cause an asteroid to spin faster; others slow it down. If asteroids are monolithic rocks undergoing random collisions, a graph of their rotation rates should show a bell-shaped distribution with a statistical "tail" of very fast rotators. If nearly all asteroids are rubble piles, however, this tail would be missing, because any rubble pile spinning faster than once every two or three hours would fly apart. Recently, several astronomers discovered that all but five observed asteroids obey a strict rotation limit. The exceptions are all smaller than about 150 meters in diameter, with an abrupt cutoff for asteroids larger than 200 meters. The evident conclusion-that asteroids larger than 200 meters across are rubble piles-agrees with recent computer modeling of collisions. A collision can blast a large asteroid to bits, but those bits will usually be moving slower than their mutual escape velocity (the lowest velocity that a body must have in order to escape the orbit of a planet). Over several hours, gravity will reassemble all but the fastest pieces into a rubble pile.
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The example of the sandcastle (in the second paragraph) serves to
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Epidemiologist: Malaria passes into the human population when a mosquito carrying the malaria protozoa bites a human who has no immunity. The malaria parasite can remain for up to forty days in the blood of an infected person. The disease cannot be passed from person to person, unless a non-infected person is exposed to the blood of an infected person. Theoretically, malaria could be eradicated in any given area, if all the mosquitoes carrying malaria in that area are exterminated. If such a course of action is carried out at a worldwide level, then the global eradication of malaria is possible.
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Which of the following, if true, suggests that the epidemiologist`s plan for eliminating malaria is not viable?
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Even though physiological and behavioral processes are maximized within relatively narrow ranges of temperatures in amphibians and reptiles, individuals may not maintain activity at the optimum temperatures for performance because of the costs associated with doing so. Alternatively, activity can occur at suboptimal temperatures even when the costs are great. Theoretically, costs of activity at suboptimal temperatures must be balanced by gains of being active. For instance, the leatherback sea turtle will hunt during the time of day in which krill are abundant, even though the water is cooler and thus the turtle`s body temperature requires greater metabolic activity. In general, however, the cost of keeping a suboptimal body temperature, for reptiles and amphibians, is varied and not well understood; they include risk of predation, reduced performance, and reduced foraging success.
One reptile that scientists understand better is the desert lizard, which is active during the morning at relatively low body temperatures (usually 33.0 C), inactive during midday when external temperatures are extreme, and active in the evening at body temperatures of 37.0 C. Although the lizards engage in similar behavior (e.g., in morning and afternoon, social displays, movements, and feeding), metabolic rates and water loss are great and sprint speed is lower in the evening when body temperatures are high. Thus, the highest metabolic and performance costs of activity occur in the evening when lizards have high body temperatures. However, males that are active late in the day apparently have a higher mating success resulting from their prolonged social encounters. The costs of activity at temperatures beyond those optimal for performance are offset by the advantages gained by maximizing social interactions that ultimately impact individual fitness.
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The passage suggests that reptiles and amphibians are able to
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Even though physiological and behavioral processes are maximized within relatively narrow ranges of temperatures in amphibians and reptiles, individuals may not maintain activity at the optimum temperatures for performance because of the costs associated with doing so. Alternatively, activity can occur at suboptimal temperatures even when the costs are great. Theoretically, costs of activity at suboptimal temperatures must be balanced by gains of being active. For instance, the leatherback sea turtle will hunt during the time of day in which krill are abundant, even though the water is cooler and thus the turtle`s body temperature requires greater metabolic activity. In general, however, the cost of keeping a suboptimal body temperature, for reptiles and amphibians, is varied and not well understood; they include risk of predation, reduced performance, and reduced foraging success.
One reptile that scientists understand better is the desert lizard, which is active during the morning at relatively low body temperatures (usually 33.0 C), inactive during midday when external temperatures are extreme, and active in the evening at body temperatures of 37.0 C. Although the lizards engage in similar behavior (e.g., in morning and afternoon, social displays, movements, and feeding), metabolic rates and water loss are great and sprint speed is lower in the evening when body temperatures are high. Thus, the highest metabolic and performance costs of activity occur in the evening when lizards have high body temperatures. However, males that are active late in the day apparently have a higher mating success resulting from their prolonged social encounters. The costs of activity at temperatures beyond those optimal for performance are offset by the advantages gained by maximizing social interactions that ultimately impact individual fitness.
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The author implies that, in the desert lizard, the advantages in some forms of social interaction
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In his magnificent biography of Keats, Nicholas Roe chronicles a forward-looking spirit, whose poetry offered a strikingly modern amalgam of the arts and sciences.?Medical allusions to nerves, arteries, bone and blood developed in tandem with deepening thoughts on human pain and suffering, says Roe. Keats`s vaunted "negative capability" allowed him to engage imaginatively with life`s transience and his own consumptive state (he suffered from tuberculosis and was not expected to live for long).?The rueful melancholy of "To Autumn" and "Ode to a Nightingale" speaks of a courageous reckoning with mortality.
Lord Byron, with customary disdain, regarded Keats as a mere dilettante of sensation and "his imagination". Roe will have little of this. The imagination at work in a poem such as "Isabella, or, the Pot of Basil" derived from Keats`s professional exposure to dissecting-room corpses. As the son of a Moorfields livery stables manager, Keats knew how the poor could serve as fodder for scalpels. Hospitals were complicit in the body-snatching trade, as the science of anatomy was in its infancy and trainee surgeons were required to practice their skills.
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Select the part of the passage that mentions the poems that were informed by Keats's illness.
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The price of the SuperPixel high definition television, by Lux Electronics, has typically been out of the range of most consumers, a few of whom nonetheless save up for the television. This past July, the SuperPixel reduced its price by 40%, and sales during that month nearly tripled. TechWare, a popular electronics magazine, claims that the SuperPixel television should continue to see sales grow at this rate till the end of August.
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Which of the following suggests that TechWare`s forecast is misguided?
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A senator, near the end of his first six-year term and running for reelection, made the claim: "Citizens of our state are thriving. While national unemployment levels have remained high, our state unemployment rate has been at astonishingly low levels for eleven years running. Clearly, everyone in our state has benefited from the economical packages I have introduced during my time in the Senate. Therefore, grateful citizens of our state ought to vote for my second term."
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This argument is most vulnerable to what criticism?
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In order to combat Carville`s rampant homeless problem, Mayor Bloomfield recently proposed a ban on sleeping outdoors in the city`s many parks. He claims that such a measure will force the homeless to either leave Carville or to find means other than sleeping in public parks.
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Which of the following, if true, suggests that Mayor Bloomfield`s plan will be successful?
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The main goal of "risk communication" is for experts to inform laypeople of the potential dangers of new technologies and ecological phenomenon. In order for experts to effectively communicate risk, they must understand the extent of the knowledge base of those whom they hope to guide. Research has found that canned messages, which make no concessions to a person`s knowledge, are likely to leave those who hear or read the message feeling befuddled or indifferent.
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Which of the following scenarios best captures the principle regarding effective "risk communication" elucidated in the passage?
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Dolphins can swim at high speeds and achieve high acceleration in the water. In 1936, Sir James Gray calculated the force dolphins should be able to exert based on their physiology. He concluded that the propulsive force they were able to exert was not enough to explain how fast they swim and accelerate.?In the 2000s, experimenters used special computer-enhanced measurements of the water in which dolphins were swimming. Through mathematical modeling, they were able to measure the force dolphins exert with their tails. As it turns out, dolphins exert considerably more force with their tails than Sir James Gray or anybody else ever expected.?Therefore, the force exerted by their tails easily explains how fast they swim and accelerate.
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