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Scientists say they have discovered hints of alien life on the Saturn"s moon. The discovery of a sort of life was announced after researchers at the US space agency, NASA, analyzed data from spacecraft Cassini, which pointed to, the existence of methane-based form of life on Saturn"s biggest moon.Scientists have reportedly discovered clues showing primitive alien beings are "breathing" in Titan"s dense atmosphere filled with hydrogen.They argue that hydrogen gets absorbed before hitting Titan"s planet-like surface covered with methane lakes and rivers. This, they say, points to the existence of some "bugs" consuming the hydrogen at the surface of the moon less than half the size of the Earth."We suggested hydrogen consumption because it"s the obvious gas for life to consume on Titan, similar to the way we consume oxygen on Earth," says NASA scientist Chris McKay. "If these signs do turn out to be a sign of life, it would be doubly exciting because it would represent a second form of life independent from water-based life on Earth."To date, scientists have not yet detected this form of life anywhere, though there are liquid water based microorganisms on Earth that grow well on methane or produce it as a waste product. On Titan, where temperatures are around 90 Kelvin (minus 290 degrees Fahrenheit), a methane based organism would have to use a substance that is liquid as its medium for living processes, but not water itself. Water is frozen solid on Titan"s surface and much too cold to support life as we know it.Scientists had expected the Sun"s interactions with chemicals in the atmosphere to produce a coating of acetylene on Titan"s surface. But Cassini detected no acetylene on the surface.The absence of detectable acetylene on the Titan"s surface can very well have a non-biological explanation, said Mark Alien, a principal investigator of the NASA Titan team."Scientific conservatism suggests that a biological explanation should be the last choice after all non-biological explanations are addressed," Alien said, "We have a lot of work to do to rule out possible non-biological explanations. It is more likely that a chemical process, without biology, can explain these results." Which of the following statement about Titan is true
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The standardized educational or psychological tests, which are widely used to aid in selecting, assigning or promoting students, employees and military personnel, have been the target of recent attacks in books, magazines, the dally press, and even in Congress. The target is wrong, for, in attacking the tests, critics divert attention from the fault that lies with ill-informed or incompetent users. The tests themselves are merely tools. Whether the results will be valuable, meaningless, or even misleading depends partly upon the tool itself but largely upon the user.All informed predictions of future performance are based upon some knowledge of relevant past performance. How well the predictions will be validated by later performance depends upon the amount, reliability and appropriateness of the information used and on the skill and wisdom with which it is interpreted. Anyone who keeps careful score knows that the information available is always incomplete and that the predictions are always subject to error.Standardized tests should be considered in this context: they provide a quick, objective method of getting some kind of information about what a person has learned, the skills he has developed, or the kind of person he is. The information so obtained has, qualitatively, the same advantages and shortcomings as other kinds of information. Whether to use tests, other kinds of information, or both in a particular situation depends, therefore, upon the empirical evidence concerning comparative validity and upon such factors as cost and availability.In general, the tests work most effectively when the traits or qualities to be measured can be most precisely defined (for example, ability to do well in a particular course of training program) and least effectively when what is to be measured or predicted cannot be well defined, for example, personality or creativity. Properly used, they provide a rapid means of getting comparable information about many people. Sometimes they identify students whose high potential has not been previously recognized. Which of the following statement is not true according to the passage
The standardized educational or psychological tests, which are widely used to aid in selecting, assigning or promoting students, employees and military personnel, have been the target of recent attacks in books, magazines, the dally press, and even in Congress. The target is wrong, for, in attacking the tests, critics divert attention from the fault that lies with ill-informed or incompetent users. The tests themselves are merely tools. Whether the results will be valuable, meaningless, or even misleading depends partly upon the tool itself but largely upon the user.All informed predictions of future performance are based upon some knowledge of relevant past performance. How well the predictions will be validated by later performance depends upon the amount, reliability and appropriateness of the information used and on the skill and wisdom with which it is interpreted. Anyone who keeps careful score knows that the information available is always incomplete and that the predictions are always subject to error.Standardized tests should be considered in this context: they provide a quick, objective method of getting some kind of information about what a person has learned, the skills he has developed, or the kind of person he is. The information so obtained has, qualitatively, the same advantages and shortcomings as other kinds of information. Whether to use tests, other kinds of information, or both in a particular situation depends, therefore, upon the empirical evidence concerning comparative validity and upon such factors as cost and availability.In general, the tests work most effectively when the traits or qualities to be measured can be most precisely defined (for example, ability to do well in a particular course of training program) and least effectively when what is to be measured or predicted cannot be well defined, for example, personality or creativity. Properly used, they provide a rapid means of getting comparable information about many people. Sometimes they identify students whose high potential has not been previously recognized. The author"s attitude toward the present test is that ______.
The standardized educational or psychological tests, which are widely used to aid in selecting, assigning or promoting students, employees and military personnel, have been the target of recent attacks in books, magazines, the dally press, and even in Congress. The target is wrong, for, in attacking the tests, critics divert attention from the fault that lies with ill-informed or incompetent users. The tests themselves are merely tools. Whether the results will be valuable, meaningless, or even misleading depends partly upon the tool itself but largely upon the user.All informed predictions of future performance are based upon some knowledge of relevant past performance. How well the predictions will be validated by later performance depends upon the amount, reliability and appropriateness of the information used and on the skill and wisdom with which it is interpreted. Anyone who keeps careful score knows that the information available is always incomplete and that the predictions are always subject to error.Standardized tests should be considered in this context: they provide a quick, objective method of getting some kind of information about what a person has learned, the skills he has developed, or the kind of person he is. The information so obtained has, qualitatively, the same advantages and shortcomings as other kinds of information. Whether to use tests, other kinds of information, or both in a particular situation depends, therefore, upon the empirical evidence concerning comparative validity and upon such factors as cost and availability.In general, the tests work most effectively when the traits or qualities to be measured can be most precisely defined (for example, ability to do well in a particular course of training program) and least effectively when what is to be measured or predicted cannot be well defined, for example, personality or creativity. Properly used, they provide a rapid means of getting comparable information about many people. Sometimes they identify students whose high potential has not been previously recognized. According to the passage, the present standardized educational tests are ______.
Why the inductive and mathematical sciences, after their first rapid development at the culmination of Greek civilization, advanced so slowly for two thousand years—and why in the following two hundred years a knowledge of natural and mathematical science has accumulated, which so vastly exceeds all that was previously known that these sciences may be justly regarded as the products of our own times—are questions which have interested the modern philosopher not less than the objects with which these sciences are more immediately familiar.The explanation which has become commonplace, that the ancients employed deduction chiefly in their scientific inquiries, while the modems employ induction, proves to be too narrow. For all knowledge is founded on observation, and proceeds from this by analysis, by induction and deduction, and if possible by verification, or by steps which are indeed parts of one method.A failure to employ adequately any one of these partial methods, an imperfection in the arts and resources of observation and experiment, carelessness in observation, neglect of relevant facts—these are the faults which cause all failures to ascertain truth; but this statement does not explain why the modem is possessed of a greater virtue, and by what means he attained his superiority. Much less does it explain the sudden growth of science in recent time.The attempt to discover the explanation of this phenomenon in theantithesis(对立面；对照；对仗) of "facts" and "theories"—in the neglect among the ancients of the former, and their too exclusive attention to the latter—proves also to be too narrow, as well as open to the charge of vagueness. Theories, if true, are facts—a particular class of facts indeed, generally complex, and if a logical connection subsists between their constituents, have all the positive attributes of theories.Nevertheless, this distinction, however inadequate it may be to explain the source of true method in science, is well founded, and suggests an important character in true method. A theory, on the other hand, if true has all the characteristics of a fact, except that its verification is possible only by indirect, remote, and difficult means. To convert theories into facts is to add simple verification, and the theory thus acquires the full characteristics of a fact. Which of the following statement is true about mathematical sciences according to the passage
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