阅读理解Are responses to odors acquired as a function of the emotional context in which they are initially perceived? Researchers recently conducted a study in which a novel odor was paired with either a positive or negative emotional experience. Ratings associated with the test odor varied in accordance with the paired emotion, such that the odor was perceived as either congenial or noisome, depending upon the quality of paired experience the participant had. 　　Olfactory sensory attributes may produce an unlearned impact when odors are irritating; in these cases discomfort is experienced simultaneously to odor sensation, an event occurring when stimulation of the trigeminal nerve occurs coterminous with olfactory sensation. Many odors elicit trigeminal stimulation to varying degrees, so that the subjective distinction between pure odor and trigeminal irritation is not possible to make, though scientists have precipitously ventured to suggest methods. While these cases may help explain why one may be immediately repelled by a certain scent, they unfortunately do not allow most scientists to establish which smells trigger innate reactions.

阅读理解Behavioral psychologists apprehend that conditioned fear responses to atone previously paired with a shock diminish, if the tone is repeatedly presented　without the shock, a process known as extinction. Since Parlor it has been hypothesized that this extinction does not erase conditioning, but forms a new memory. Research has now demonstrated that destruction of the infralimbic cortice blocks recall of fear extinction, indicating that it might store long-term extinction memory. Infralimbic neurons recorded during fear conditioning and extinction fire to the tone only when rats are recalling extinction on the following day, and rats indicating the least fear responses also demonstrate the greatest increase in infralimbic tone responses. Conditioned tones paired with brief electrical stimulation of infralimbic cortex elicit low fear responses in rats that have not undergone extinction. Thus, stimulation resembling extinction-induced infralimbic tone responses is able to simulate extinction memory.

阅读理解Electronic computer speeds are restricted not only by the speed of electrons in matter but also by the escalating density of interconnections necessary to connect the electronic gates on microchips. Electrical engineers and physicists have been developing and augmenting the technologies of analog and digital optical computing, in which the information is primarily carried by photons rather than by electrons. Optical computing could, in principle, generate much higher computer speeds, but one of the problems it has encountered lies in accuracy, for these devices have practical limits of 8 to 11 bits of accuracy in basic operations. Recent research has evinced that digital partitioning algorithms in tandem with error-correction codes, can substantially enhance the accuracy of optical computing operations. In the near term optical computers will most likely be hybrid optical/electronic systems that preprocess input data for computation and post-process output data via electronic circuits, but nevertheless, the prospect of all-optical computing remains highly attractive.

阅读理解That large regions of the galaxy can be influenced by the formation of massive stars in a few localized regions requires that star formation somehow be coordinated over long periods of time. The process commences with a single O-type star or a cluster of such stars in a giant molecular cloud, around which stellar radiation, winds and explosions carve a modest cavity from of the surrounding interstellar medium, concomitantly destroying the progenitor cloud. Perchance this disturbance triggers star formation in a nearby cloud, and so on, until the interstellar medium in this corner of the galaxy resembles Swiss cheese, composed of what theorists have recently begun to refer to as bubbles, or superbubbles, one of the most exciting discoveries in astrophysics in years. Within a hot bubble, the sun has revealed itself in x-rays emitted by highly ionized trace ions such as oxygen and at some point in the process of its formation, nearby bubbles commence to overlap, coalescing into a superbubble. The energy from more and more O-type stars feeds this expanding superbubble until its natural buoyancy stretches it from the midplane up toward the halo, forming a chimney―the superbubble thus becomes a pathway for hot interior gas to spread into the upper reaches of the galactic atmosphere, producing a widespread corona. Far from its source of energy, the coronal gas slowly starts to cool and condense into clouds. Over eons, these clouds fall back to the galaxy''s mid-plane, completing the fountain-like cycle and replenishing the galactic disk with cool clouds from which star formation begins anew. Star formation often occurs in sporadic but intense bursts, but in the Milky Way the competing feedback effects almost balance out, so that stars form at an unhurried pace―just 10 per year on average, except in some galaxies where positive feedback has gained the upper hand. 20 million to 50 million years ago, star formation in the central parts of M82 began running out of control. Our galaxy, too, may have had sporadic bursts, and the way these starbursts occur, and what turns them off must be tied to the complex relation between stars and the tenuous atmosphere from which they precipitate. 　　Progress will be made in this complicated subject as astronomers continue to study how the medium is cycled through stars, through the different phases of the medium, and between the disk and the halo. Observations of other galaxies give astronomers a bird''s-eye view of the interstellar goings-on, and answer such a critical question as whether stars are really the main source of power for the interstellar medium. The loop above the Cassiopeia superbubble1looks uncomfortably similar to the prominences that arch above the surface of the sun, prominences which owe much to the magnetic field in the solar atmosphere, and scientists have begun to wonder if magnetic activity dominates our galaxy''s atmosphere.

阅读理解Many microorganisms survive such environmental stresses as heat, cold and desiccation not by rapid rates of mitosis, but by producing specialized cells designed to persist in a dormant state in hostile environments. Most fungi, for Line example, yield single-celled spores, which, through wind distribution, can survive for long periods of time before germinating and sprouting fungal filaments of their own. Other types of bacteria produce a special type of spore called an endospore, capable of withstanding such extremes as boiling and freezing temperatures, and even ultraviolet radiation. 　　Though research results remain tentative, several factors may protect endospores from environmental stress: they have a low water content, unusual proteins and a tough spore coat absent in mature bacterial cells. When garden fruits and vegetables, which may contain botulism endospores, are preserved by canning at boiling temperatures, we know that these spores survive the heat and sprout in the food, and as a result, the bacteria generate the botulism toxin that can lead to food poisoning―proof of their magnificent resilience.

阅读理解Disease is a fluid concept influenced by societal and cultural attitudes that change diachronically in response to new scientific and medical discoveries. Historically, doctors defined a disease according to a cluster of symptoms, and Live as their clinical descriptions became more sophisticated, they started to classify diseases into separate groups, so that from this medical taxonomy came new insights into disease etiology. Before the 20th century, schizophrenia and syphilitic insanity were treated as the same disease, but by early 1900 it became evident that psychoses without associated dementia represented a separate disease for which the term schizophrenia was then coined. The definition of schizophrenia continues to evolve from the psychiatric disease of the 1960s to an illness with a suspected genetic etiology, though the existence of such an etiology remains uncertain. While an optimistic hunt is still on for the genes involved, we must continue to define schizophrenia in terms of the presence or absence of "positive" and "negative" symptoms. 　　Labeling someone as diseased, however, has enormous individual, social, financial, and physical implications, for irrespective of disease symptoms, the label itself may lead to significant distress. Individuals with asymptomatic conditions, including genetic variations, may be perceived by themselves or others as having a disease. It is not that labeling someone as diseased is always positive―it does have severe ramifications, affecting decisions to have children or resulting in unjust treatment by life, medical, and disability insurers―but it can be beneficial, legitimizing symptoms, clarifying issues of personal responsibility, and improving accessibility to health care. Nevertheless, deviations from normal that are not associated with risk should not be considered synonymous with disease. Two schools― nominalist and essentialist or reductionist―have debated the clinical criteria used to label a patient as diseased. Nominalists label symptoms with a disease name, such as schizophrenia, and do not offer an explanation of the underlying etiology, while essentialists contend that for every disease there is an underlying pathological etiology, and now argue that the essential lesion defining the disease state is a genetic abnormality. 　　It has been suggested that diseases defined according to the essentialist tradition may be precisely wrong, whereas those defined in the nominalist traditional may be roughly accurate. But in labeling a disease state, we must consider both the phenotype (symptoms) or the genotype (genetic abnormality), for the former describes a state that places individuals at some definable risk of adverse consequences, while the latter helps suggest specific genetic or pharmacologic therapies. Thus, both clinical criteria and genetic abnormalities should be used to define a disease state, and the choice of a disease definition will vary according to what one wishes to achieve, the genetic counseling of family members or the effective treatment of the patient.

阅读理解Feminist critics have long debated the extent to which gender plays a role in the creation and interpretation of texts. Androgynist poetics, rooted in mid-Victorian women''s writing, contends that the creative mind is sexless, but Line from the 1970s on, many feminist critics rejected the idea of the genderless mind, finding that the imagination cannot evade conscious or unconscious structures of gender which is part of culture-determination where separating imagination from the self is impossible. 　　The Female Aesthetic, expressing a unique female consciousness in literature, spoke of the "female vernacular, the Mother Tongue, a powerful but neglected women''s culture." Virginia Woolf discusses how a woman writer seeks within herself "the pools, the depths, the dark places where the largest fish slumber," inevitably colliding against her own sexuality to Confront "something about the body, about the passions." Accessible to men and women alike, but representing female sexual morphology, this method sought a way of writing which literally embodied the female, thereby fighting the subordinating, linear style of classification or distinction. 　　It must be admitted that there are problems with the Female Aesthetic that feminist critics themselves recognized. For instance, they avoided defining exactly what constituted their writing style, as any definition would then categorize it and safely subsume it as a genre under the linear patriarchal structure?―its very restlessness and ambiguity defied identification as part of its identity. Some feminists and women writers could feel excluded by the surreality of the Female Aesthetic and its stress on the biological forms of female experience, which also bear close resemblance to essentialism. Men may try their hand at writing woman''s bodies, but according to the feminist critique, only. a woman whose very biology gave her an edge could read these texts successfully―a position which, worst of all, risked marginalization of women''s literature and theory. 　　Later, Gynocritics attempted to resolve some of these problems, by agreeing that women''s literature lay as the central concern for feminist criticism but rejecting the concept of an essential female identity and style, while simultaneously seeking to revise Freudian structures by emphasizing a Pre-Oedipal phase wherein the daughter''s bond to her mother inscribes the key factor in gender identity. Matriarchal values dissolve intergenerational conflicts and build upon a female tradition of literature rather than the struggle of Oedipus and Lais at the crossroads. Lastly and most promising in its achievement of a delicate balance are developments of an over-arching gender theory, which considers gender, both male and female, as a social construction built on biological differences. Gender theory proposes to explore ideological inscription and the literary effects of the sex/gender system, opening up the literary theory stage and bringing in questions of masculinity into feminist theory. Taking gender as a fundamental analytic category brings feminist criticism from the margin to the center, though it risks depoliticizing the study of women.

阅读理解Feminist critics''have often pondered whether a postmodern language may be articulated that obviates the essentialist arrogance of much modernist and some feminist discourse and does not reduce feminism to silences or a purely negative and reactionary stance. This ideal may be actualized in a discourse that recognizes itself as historically situated, '' as motivated by values and, thus, political interests, and as a human practice without transcendent justification. The author Dorothy Allison meets these criteria by focusing on women who have been marginalized by totalizing forces and ideas, while simultaneously reminding the reader, through the wide range of women that she portrays and their culpability in her protagonists'' predicaments, that unlike pure and transcendent heroes, women are real characters and morally complex. Allison insists that humans are burdened with the responsibility of fashioning their own stories, quotidian as they may be, and .while these will never offer the solace of transcendent justification, the constant negotiation between the word and the world avoids reticence on the one hand and the purely negative on the other.

阅读理解From the beginning, the idea of a finite universe ran into its own obstacle, the apparent need for an edge, a problem that has only recently been grappled with. Aristotle''s argument, that the universe is finite, and that a boundary was necessary to fix an absolute reference frame, held only until scientists wondered what happened at the far side of the edge. In other words, why do we not redefine the "universe" to include that other side? 　　Riemann ingeniously replied by proposing the hypersphere, the three- dimensional surface of a four-dimensional ball. Previously it was supposed that the ultimate physical reality must be a Euclidean space of some dimension, and thus if space were a hypersphere, it would need to sit in a four-dimensional Euclidean space that allows us to view it from the outside. But according to Riemann, it would be perfectly acceptable for the universe to be a hypersphere and not embedded in any higher-dimensional space; nature need not therefore cling to the ancient notion. According to Einstein''s powerful but limited theory of relativity, space is a dynamic medium that can curve in one of three ways, depending on the distribution of matter and energy within it, but because we are embedded in space, we cannot see the flexure directly but rather perceive it as gravitational attraction and geometric distortion of images. Thus, to determine which of the three geometries our universe has, astronomers are forced to measure the density of matter and energy in the cosmos, whose amounts appear at present to be insufficient to force space to arch back on itself in "spherical" geometry. Space may also have the familiar Euclidean geometry, like that of a plane, or a "hyperbolic" geometry, like that of a saddle. Furthermore, the universe could be spherical, yet so large that the observable part seems Euclidean, just as a small patch of the earth''s surface looks flat. 　　We must recall that relativity is a purely local theory: it predicts the curvature of each small volume of space--its geometry--based on the matter and energy it contains, and the three plausible cosmic geometries are consistent with many different topologies: relativity would describe both a torus and a plane with the same equations, even though the torus is finite and the plane is infinite. Determining the topology therefore requires some physical understanding beyond relativity, in order to answer the question, for instance, of whether the universe is, like a plane, "simply connected", meaning there is only one direct path for light to travel from a source to an observer. A simply connected Euclidean or hyperbolic universe would indeed be infinite--and seems self-evident to the layman--but unfortunately the universe might instead be "multiply-connected", like a torus, in which case there are many different such paths. An observer could see multiple images of each galaxy and easily interpret them as distinct galaxies in an endless space, much as a visitor to a mirrored room has the illusion of seeing a huge crowd, and for this reason physicists have yet to conclusively determine the shape of the universe.

阅读理解The distinction between making art and thinking and writing about it should imply neither a mutual exclusiveness nor a hierarchic differentiation of these processes. Leonardo demonstrated that producing art and theorizing about Line it need not be antithetically opposed activities and that meaningful contributions can be achieved successfully in more than one field. Inexplicably, few theorists have built as memorable architectural structures as his and even fewer artists have been entrusted with the directorship of an influential art institution. Unfortunately, as theory and practice became more specialized in the modernera and their operational framework clearly defined both in the cultural milieu and the educational process, their independent paths and boundaries have curtailed possibilities of interaction. The creations of categories and divisions have further emphasized highly individualized idiosyncrasies and, by exposing differences, diminished the value of a unifying artistic vocabulary. The transformative cultural process of the last decades has critically examined the artificial separations between theoretical and studio practices and disclosed viable connections between making, writing, thinking, looking and talking about art. The recent dialogue between the various components of the artistic discourse has recognized the common denominators shared by theoretical analyses and artistic production, one of which is clearly exposed by the argument that the central objective of the theorist and artist is to unmask and understand artistic meanings in painting or text. 　　The notion that "true" art is the product of individuals who are incapable of in-depth understanding, in stark contrast to erudite, restrained and controlled scholars, is an outdated model. The assumption that artists make art but cannot or do not have to talk or write about it and that theorists rarely know anything about the creative process, has been consistently refuted by the many texts written from Leonardo da Vinci to Mary Kelly. Even van Gogh, a martyr of the stereotypical "misunderstood genius," whose artistic career has been distorted by scores of films and books, wrote with lucidity and insight about art and his work. Apparently, the "mystery" of the creative process, jealously protected by artists but also selectively cultivated by some art historians has been both a fascination and frustration for those extrinsic to the process and artists have exposed the intimacy of creativity while acknowledging the role of cognition in creativity. 　　Even the ironic and subversive demise of authorship of the post-modern and electronic age acknowledges, at least indirectly, the value of the artist''s individual participation. However, many contemporary artists have abandoned the hierarchic segregation of the inner realm of the creator and, by combining theoretical and studio practices, brought a reconciliatory tone to the processes of making art and analyzing it. Their works, which are often simultaneously artistic productions and critique of the artistic discourse, make use of visual and textual forms to expose the connection between looking and thinking as the essential attribute to both creating and understanding art.

阅读理解Until recently, scrutiny of tree-ring records seemed to establish that a prolonged dry spell called the Great Drought drove the Anasazi Indians to abandon their magnificent stone villages on the Colorado Plateau. Line Groundbreaking climatological studies have convinced many archaeologists, however, that the Great Drought was not sufficiently austere to coerce the sudden evacuation of the Anasazi. Reviewing tree ring records, including moisture levels, Van West disputed the Great Drought theory by presenting evidence that enough corn could have been grown during the drought to support the population, that the Anasazi had weathered many severe droughts in the past, and that the evacuation actually began before the dry spell set in. 　　Belying the popular image of the Anasazi as a peaceable kingdom of farmers and potters, some new research puts the blame for the evacuation on a bloody internecine war. Noting that the Anasazi had been suffering from malnutrition, shorter life spans and increased infant mortality, Adler suggests that the Anasazi were not able to move around freely to farm because their once open range was becoming balkanized into hostile fiefdoms. Perhaps as a reaction to drier weather, people in the Mesa Verde area began building dams and canals to trap and divert water, and the result may have been conflict and warfare. Unfortunately, other archeologists, having trouble envisioning how even drought, balkanization and warfare could make an entire civilization evacuate, are trying to combine archeological evidence with anthropological studies of the modern pueblo Indians to make the case that the Anasazi were roiled by a religious crisis as divisive as European medieval heresies. Analyzing the spread of religious symbols found on rocks or pottery and the distribution of ceremonial structures, some argue that the Anasazi may have been pulled from their homeland by a new religion emerging to the south, whose egalitarian spirit would have had great appeal to a civilization, like the Anasazi''s, that was entering a dark age. Ware comes closest to a plausible synthesis of his predecessors'' theories in suggesting that the Anasazi world was rocked by a spiritual crisis catastrophic enough to cause a collapse of a civilization, and that the uprooted Anasazi apparently embraced a variety of new beliefs on migration to their new homes. 　　Ware further argues that the precipitating factor in the evacuation may have been a change in climate after all. Recent climatological studies suggest that indeed, rainfall patterns were disrupted in a way that might have made the Anasazi disillusioned with their old religion: the customary pattern of heavy snows in the winter followed by summer monsoons had become unpredictable. Even if there was not a great drought, moisture may have been coming at the wrong times, and the summer rains, essential for nourishing the spring crops, were no longer reliable―the rain dances were not working anymore. Thus, Ware''s theory accommodates the greatest variety of factors that may explain the Anasazi''s evacuation.

单选题Analogies

单选题 k ak pk 1 100 0.10 2 200 0.25 3 300 0.20 4 400 0.25 5 500 0.20 If in an experiment the probabilities of obtaining the values a1，a2，a3，a4， and a5are p1，P2，P3，P4 and P5，respectively，then the expected value is defined as a1p1+a2p2+a3p3+a4p4+a5p5．For the values and their corresponding probabilities in the table above，what is the expected value? A. 350 B. 320 C. 300 D. 270 E. 250

单选题If a particular vaccine is produced only by one company at a single facility, there is a possibility that the supply of vaccine could grow ------- if the company decides to cease production.

单选题In a happy, somewhat boisterous celebration of the European discovery of America, the major phase of the Columbus Cinquecentennial got off to ______start on Friday.(A) a slow(B) a rousing(C) a reluctant(D) an indifferent(E) a quiet

单选题IMMEDIATE:

单选题ADHERENT:(A) fugitive(B) dissembler(C) opponent(D) educator(E) witness

单选题The authority of voice in Frazer's writing strikes many readers today as ______ colonialism; his prose seems as invulnerable and expansive as something on which the sun was presumed never to set.(A) consonant with(B) independent of(C) ambivalent toward(D) cognizant of(E) detrimental to

单选题Childhood memoirs often gain their poignancy through a sense of displacement: each lesson in experience is accompanied by a loss of-------.

单选题xpercentof24is12