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(This passage was excerpted from material published in 1996.)When a large body strikes a planet or moon, material is ejected, thereby creating a hole in the planet and a localdeficit of mass. This deficit shows up as a gravity anomaly: the removal of the material that has been ejected to make the hole results in an area of slightly lower gravity than surrounding areas. One would therefore expect that all of the large multi-ring impact basins on the surface of Earth's Moon would show such negative gravity anomalies, since they are, essentially, large holes in the lunar surface. Yet data collected in 1994 by the Clementine spacecraft show that many of these lunar basins have no anomalously low gravity and some even have anomalously high gravity. [hl:1]Scientists[/hl:1] speculate that early in lunar history, when large impactors struck the Moon's surface, causing millions of cubic kilometers of crustal debris to be ejected, denser material from the Moon's mantle rose up beneath the impactors almost immediately, compensating for the ejected material and thus leaving no low gravity anomaly in the resulting basin. Later, however, as the Moon grew cooler and less elastic, rebound from large impactors would have been only partial and incomplete. Thus today such [hl:3]gravitational compensation[/hl:3] probably would not occur: the outer layer of the Moon is too cold and stiff.
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Linda Kerber argued in the mid-1980's that after the American Revolution (1775-1783), an ideology of "republican motherhood" resulted in a surge of educational opportunities for women in the United States. Kerber maintained that the leaders of the new nation wanted women to be educated in order to raise politically virtuous sons. A virtuous citizenry was considered essential to the success of the country's republican form of government; virtue was to be instilled not only by churches and schools, but by families, where the mother's role was crucial. Thus, according to Kerber, motherhood became pivotal to the fate of the republic, providing justification for an unprecedented attention to female education.Introduction of the republican motherhood thesis dramatically changed historiography. Prior to Kerber's work, educational historians barely mentioned women and girls; Thomas Woody's 1929 work is the notable exception. Examining newspaper advertisements for academies, Woody found that educational opportunities increased for both girls and boys around 1750. Pointing to "An Essay on Woman" (1753) as reflecting a shift in view, Woody also claimed that practical education for females had many advocates before the Revolution. Woody's evidence challenges the notion that the Revolution changed attitudes regarding female education, although it may have accelerated earlier trends. Historians' reliance on Kerber's "republican motherhood" thesis may have obscured the presence of these trends, making it difficult to determine to what extent the Revolution really changed women's lives.
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This passage was adapted from an article written in 1990.Research data indicate that there is a great deal of poverty in the United States among single-parent families headed by women. This problem could result from the fact that women's wages are only 60 percent of men's. Some economists believe that rigorous enforcement of existing equal pay laws would substantially decrease this wage inequity. But equal pay laws are ineffectual when women and men are concentrated in different occupations because such laws require only that women and men doing the same jobs be paid the same. Since gender concentration exists (for example, 80 percent of clerical workers are women), other economists argue that a comparable worth standard, which would mandate that women and men in any jobs that require comparable training and responsibility be paid the same, should be applied instead. But some [hl:2]policy analysts[/hl:2] assert that, although comparable worth would virtually equalize male and female wages, many single-parent families headed by women would remain in poverty because many men earn wages that are below the poverty line. These policy analysts believe that the problem is not caused primarily by wage inequity but rather by low wages coupled with single parenthood, regardless of sex. As a solution, they challenge the government's assumption that a family's income should depend primarily on wages and urge the government to provide generous wage supplements (child and housing allowances) to single parents whose wages are low.
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Is it possible to decrease inflation without causing a recession and its concomitant increase line in unemployment? The orthodox answer is "no." whether they support the "inertia" theory of inflation (that today's inflation rate is caused by yesterday's inflation, the state of the economic cycle, and external influences such as import prices) or the "rational expectations" theory (that inflation is caused by workers' and employers' expectations, coupled with a lack of credible monetary and fiscal policies), most economists agree that tight monetary and fiscal policies, which cause recessions, are necessary to decelerate inflation. They point out that in the 1980's, many European countries and the United States conquered high (by these countries' standards) inflation, but only by applying tight monetary and fiscal policies that sharply increased unemployment. Nevertheless, some governments' policymakers insist that direct controls on wages and prices, without tight monetary and fiscal policies, can succeed in decreasing inflation. Unfortunately, because this approach fails to deal with the underlying causes of inflation, wage and price controls eventually collapse, the hitherto-repressed inflation resurfaces, and in the meantime, though the policy-makers succeed in avoiding a recession, a frozen structure of relative prices imposes distortions that do damage to the economy's prospects for long-term growth.
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In most earthquakes the Earth's crust cracks like porcelain, Stress builds up until a fracture forms at a line depth of a few kilometers and the crust slips to relieve the stress. Some earthquakes, however, take place hundreds of kilometers down in the Earth's mantle, where high pressure makes rock so ductile that it flows instead of cracking, even under stress severe enough to deform it like [hl:6]putty[/hl:6]. How can there be earthquakes at such depths?That such deep events do occur has been accepted only since 1927. when the seismologist Kiyoo Wadati convincingly demonstrated their existence. Instead of comparing the arrival times of seismic waves at different locations, as earlier researchers had done, Wadati relied on a time difference between the arrival of primary(P) waves and the slower secondary(S) waves. Because P and S waves travel at different but fairly constant speeds, the interval between their arrivals increases in proportion to the distance from the earthquake focus, or initial rupture point.For most earthquakes, Wadati discovered, the interval was quite short near the epicenter; the point on the surface where shaking is strongest. For a few events, however, the delay was long even at the epicenter. Wadati saw a similar pattern when he analyzed data on the intensity of shaking. Most earthquakes had a small area of intense shaking, which weakened rapidly with increasing distance from the epicenter. but others were characterized by a lower peak intensity, felt over a broader area. Both the P-S intervals and the intensity patterns suggested two kinds of earthquakes: the more common shallow events, in which the focus lay just under the epicenter, and deep events, with a focus several hundred kilometers down.The question remained: how can such quakes occur, given that mantle rock at a depth of more than 50 kilometers is too ductile to store enough stress to fracture? Wadati's work suggested that deep events occur in areas (now called Wadati-Benioff zones) where one crustal plate is forced under another and descends into the mantle. The descending rock is substantially cooler than the surrounding mantle and hence is less ductile and much more liable to fracture.
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In mid-February 1917 a women's movement independent of political affiliation erupted in New York City, the stronghold of the Socialist party in the United states. Protesting against the high cost of living, thousands of women refused to buy chickens, fish, and vegetables. The boycott shut down much of the City's foodstuffs marketing for two weeks, riveting public attention on the issue of food prices, which had increased partly as a result of increased exports of food to Europe that had been occurring since the outbreak of the First World War. By early 1917 the Socialist party had established itself as a major political presence in New York City. New York Socialists, whose customary spheres of struggle were electoral work and trade union organizing, seized the opportunity and quickly organized an extensive series of cost-of-living protests designed to direct the women's movement toward Socialist goals. Underneath the Socialists' brief commitment to cost-of-living organizing lay a basic indifference to the issue itself. While some Socialists did view price protests as a direct step toward socialism, most Socialists ultimately sought to divert the cost-of-living movement into alternative channels of protest. Union organizing, they argued, was the best method through which to combat the high cost of living. For others, cost-of-living or organizing was valuable insofar as it led women into the struggle for suffrage, and similarly, the suffrage struggle was valuable insofar as it moved United States society one step closer to socialism.Although New York's Socialists saw the cost-of-living issue as, at best ,secondary or tertiary to the real task at hand, the boycotters, by sharp contrast, joined the price protest movement out of an urgent and deeply felt commitment to the cost-of-living issue. A shared experience of swiftly declining living standards caused by rising food prices drove these women to protest. Consumer organizing spoke directly to their daily lives and concerns; they saw cheaper food as a valuable end in itself. Food price protests were these women's way of organizing at their own workplace, as workers whose occupation was shopping and preparing food for their families.
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Although recent censure of corporate boards of directors as "passive" and "supine" may be excessive, those who criticize board performance have plenty of substantive ammunition. Too many corporate boards fail in their two crucial responsibilities of overseeing long-term company strategy and of selecting, evaluating, and determining appropriate compensation of top management. At times, despite disappointing corporate performance, compensation of chief executive officers reaches indefensibly high levels, Nevertheless, suggestions that the government should legislate board reform are premature. There are ample opportunities for boards themselves to improve corporate performance.Most corporate boards' compensation committees focus primarily on peer-group comparisons. They are content if the pay of top executives approximates that of the executives of competing firms with comparable short-term earnings or even that of executives of competing firms of comparable size. However, mimicking the compensation policy of competitors for the sake of parity means neglecting the value of compensation as a means of stressing long-term performance. By tacitly detaching executive compensation policy from long-term performance, committees harm their companies and the economy as a whole. The committees must develop incentive compensation policies to emphasize long-term performance. For example a board's compensation committee can, by carefully proportioning straight salary and such short-term and long-term incentives as stock options, encourage top management to pursue a responsible strategy.
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Astronomers theorize that a black hole forms when a massive object shrinks catastrophically under its own gravity, leaving only a gravitational field so strong that nothing escapes it. Astronomers must infer the existence of black holes, which are invisible, from their gravitational influence on the visible bodies surrounding them. For example, observations indicate that gas clouds in galaxy M87 are whirling unusually fast about the galaxy's center. [hl:1]Most astronomers[/hl:1] believe that the large concentration of mass at the galaxy's center is a black hole whose gravity is causing the gas to whirl. A few skeptics have argued that the concentration of mass necessary to explain the speed of the whirling gas is not necessarily a black hole: the concentration in M87 might be a cluster of a billion or so dim stars.The same hypothesis might have been applied to the galaxy NGC 4258, but the notion of such a cluster's existing in NGC 4258 was severely undermined when astronomers measured the speed of a ring of dust and gas rotating close to the galaxy's center. From its speed, they calculated that the core's density is more than 40 times the density estimated for any other galaxy. If the center of NGC 4258 were a star cluster, the stars would be so closely spaced that collisions between individual stars would have long ago torn the cluster apart.
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Social learning in animals is said to occur when direct or indirect social interaction facilitates the acquisition of a novel behavior. It usually takes the form of an experienced animal (the demonstrator) performing a behavior such that the naive animal (the observer) subsequently expresses the same behavior sooner, or more completely, than it would have otherwise. One example of social learning is the acquisition of preferences for novel foods.Some experiments have suggested that among mammals, social learning facilitates the identification of beneficial food items, but that among birds, social learning helps animals avoid toxic substances. For example, one study showed that when red-wing blackbirds observed others consuming a colored food or a food in a distinctly marked container and then becoming ill, they subsequently avoided food associated with that color or container. Another experiment showed that house sparrows consumed less red food after they observed others eating red food that was treated so as to be noxious. Studies on nonavian species have not produced similar results, leading researchers to speculate that avian social learning may be fundamentally different from that of mammals.But Sherwin's recent experiments with domestic hens do not support the notion that avian social learning necessarily facilitates aversion to novel foods that are noxious or toxic. Even when demonstrator hens reacted with obvious disgust to a specific food, via vigorous head shaking and bill wiping, there was no evidence that observers subsequently avoided eating that food. Sherwin's research team speculated that ecological or social constraints during the evolution of this species might have resulted in there being little benefit from the social learning of unpalatability, for instance, selective pressures for this mode of learning would be reduced if the birds rarely encountered noxious or toxic food or rarely interacted after eating such food, or if the consequences of ingestion were minimal. In a related experiment, the same researchers showed that if observer hens watched demonstrator hens react favorably to food of a particular color, then observer hens ate more food of that color than they ate of food of other colors. These results confirmed that avian species can develop preferences for palatable food through social learning.
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Carotenoids, a family of natural pigments, form an important art of the colorful signals used by many animals. Animals acquire carotenoids either directly (from the plants and algae that produce them) or indirectly (by eating insects) and store them in a variety of tissues. Studies of several animal species have shown that when choosing mates, females prefer males with brighter carotenoid-based coloration. Owens and Olson hypothesize that the presence of carotenoids, as signaled by coloration, would be meaningful in the context of mate selection if carotenoids were either rare or required for health. The [hl:3]conventional view[/hl:3] is that carotenoids are meaningful because they are rare: healthier males can forage for more of the pigments than can their inferior counterparts. Although this may be true, there is growing evidence that carotenoids are meaningful also because they are required: they are used by the immune system and for detoxification processes that are important for maintaining health. It may be that males can use scarce carotenoids either for immune defense and detoxification or for attracting females. Males that are more susceptible to disease and parasites will have to use their carotenoids to boost their immune systems, whereas males that are genetically resistant will use fewer carotenoids for fighting disease and will advertise this by using the pigments for flashy display instead.
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Customer loyalty programs are attempts to bond customers to a company and its products and services by offering incentives—such as airline frequent flyer programs or special credit cards with valuable benefits—to loyal customers. In support of loyalty programs, companies often invoke the "80/20" principle, which states that about 80 percent of revenue typically comes from only about 20 percent of customers. However, this profitable 20 percent are not necessarily loyal buyers, especially in the sense of exclusive loyalty. Studies have demonstrated that only about 10 percent of buyers for many types of frequently purchased consumer goods are 100 percent loyal to a particular brand over a one-year period. Moreover, 100-percent-loyal buyers tend to be light buyers of the product or service. "Divided loyalty" better describes actual consumer behavior, since customers typically vary the brands they buy. The reasons for this behavior are fairly straightforward: people buy different brands for different occasions or for variety, or a brand may be the only one in stock or may offer better value because of a special deal. Most buyers who change brands are not lost forever; usually, they are heavy consumers who simply prefer to buy a number of brands. Such multibrand loyalty means that one company's most profitable customers will probably be its competitors' most profitable customers as well.Still, advocates of loyalty programs contend that such programs are beneficial because the costs of serving highly loyal customers are lower, and because such loyal customers are less price sensitive than other customers. It is true that when there are start-up costs, such as credit checks, involved in serving a new customer, the costs exceed those of serving a repeat customer. However, it is not at all clear why the costs of serving a highly loyal customer should in principle be different from those of serving any other type of repeat customer. The key variables driving cost are size and type of order, special versus standard order, and so on, not high-loyalty versus divided-loyalty customers. As for price sensitivity, highly loyal customers may in fact come to expect a price discount as a reward for their loyalty.
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In a 1984 book, Claire C.Robertson argued that, before colonialism, age was a more important indicator of status and authority than gender in Ghana and in Africa generally. British colonialism imposed European-style male-dominant notions upon more egalitarian local situations to the detriment of women generally, and gender became a defining characteristic that weakened women's power and authority.[hl:3]Subsequent research in Kenya convinced Robertson that she had overgeneralized about Africa.[/hl:3] Before colonialism, gender was more salient in central Kenya than it was in Ghana, although age was still crucial in determining authority. In contrast with Ghana, where women had traded for hundreds of years and achieved legal majority (not unrelated phenomena), the evidence regarding central Kenya indicated that women were legal minors and were sometimes treated as male property, as were European women at that time. Factors like strong patrilineality and patrilocality, as well as women's inferior land rights and lesser involvement in trade, made women more dependent on men than was generally the case in Ghana. However, since [hl:4]age apparently remained the overriding principle of social organization in central Kenya[/hl:4], some senior women had much authority. Thus, Robertson revised her hypothesis somewhat, arguing that in determining authority in precolonial Africa age was a primary principle that superseded gender to varying degrees depending on the situation.
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While acknowledging that there are greater employment opportunities for Latin American women in cities than in the countryside, social science theorists have continued to argue that urban migration has unequivocally hurt women's status. However, the effects of migration are more complex than these theorists presume. For example, effects can vary depending on women's financial condition and social class. Brazilian women in the lowest socioeconomic class have relatively greater job opportunities and job security in cities than do men of the same class, although there is no compelling evidence that for these women the move to the city is a move out of poverty. Thus, these women may improve their status in relation to men but at the same time may experience no improvement in their economic standing.In addition, working outside the home, which is more common in urban than in rural areas, helps women in the lowest socioeconomic class make contacts to extend exchange networks—the flow of gifts, loans, or child care from those who currently have access to resources to those who do not. Moreover, poor women working in urban areas actively seek to cultivate long-term employer-employee relations. When an emergency arises that requires greater resources than an exchange network can provide, these women often appeal for and receive aid from their wealthy employers. However, the structure of many poor women's work - often a labor force of one in an employer's home - makes it difficult for them to organize to improve their economic conditions in general.Not surprisingly, then, [hl:4]Latin American women in the lowest socioeconomic class differ in their opinions about the effects of urban migration on their lives. Some find urban living, with access to electricity and running water, an improvement and would never return to the countryside. Others, disliking the overcrowding and crime, would return to the countryside if there were work opportunities for them there.[/hl:4] Thus, urban life has had both negative and positive impacts on women's lives. In general, urban migration has not provided economic prosperity or upward mobility for women in the lowest socio-economic class, despite their intelligent and energetic utilization of the resources available to them.
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Federal efforts to aid minority businesses began in the1960's when the Small Business Administration (SBA)began making federally guaranteed loans and government-sponsored management and technical assistanceavailable to minority business enterprises. While thisprogram enabled many minority entrepreneurs toform new businesses, the results were disappointing,since managerial inexperience, unfavorable locations,and capital shortages led to high failure rates. Even 15years after the program was implemented, minoritybusiness receipts were not quite two percent of the nationaleconomy's total receipts.Recently federal policymakers have adopted anapproach intended to accelerate development of theminority business sector by moving away from directlyaiding small minority enterprises and toward supportinglarger, growth-oriented minority firms through intermediary companies. In this approach, large corporationsparticipate in the development of successful and stableminority businesses by making use of governmentsponsored venture capital. The capital is used by aparticipating company to establish a Minority EnterpriseSmall Business Investment Company or MESBIC. TheMESBIC then provides capital and guidance to minoritybusinesses that have potential to become future suppliersor customers of the sponsoring company.MESBIC's are the result of the belief that providingestablished firms with easier access to relevant management techniques and more job-specific experience, aswell as substantial amounts of capital, gives those firmsa greater opportunity to develop sound business foundations than does simply making general managementexperience and small amounts of capital available.Further, since potential markets for the minority businesses already exist through the sponsoring companies,the minority businesses face considerably less risk interms of location and market fluctuation. Followingearly [hl:5]financial and operating problems[/hl:5], sponsoringcorporations began to capitalize MESBIC's far abovethe legal minimum of $500,000 in order to generatesufficient income and to sustain the quality of management needed. MESBIC'c are now emerging as increasingly important financing sources for minority enterprises.Ironically, MESBIC staffs, which usually consist ofHispanic and Black professionals, tend to approachinvestments in minority firms more pragmatically thando many MESBIC directors, who are usually seniormanagers from sponsoring corporations. The latteroften still think mainly in terms of the "social responsibility approach" and thus seem to prefer deals that areriskier and less attractive than normal investment criteriawould warrant. Such differences in viewpoint have produced uneasiness among many minority staff members,who feel that minority entrepreneurs and businessesshould be judged by established business considerations.These staff members believe their point of view is closerto the original philosophy of MESBIC's and they areconcerned that, unless a more prudent course is followed, MESBIC directors may revert to policies likelyto re-create the disappointing results of the original SBAapproach.
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New observations about the age of some globular clusters in our Milky Way galaxy have cast doubt on a long-held theory about how the galaxy was formed. The Milky Way contains about 125 globular clusters (compact groups of anywhere from several tens of thousands to perhaps a million stars) distributed in a roughly spherical halo around the galactic nucleus. The stars in these clusters are believed to have been born during the formation of the galaxy, and somay be considered relics of the original galactic nebula, holding vital clues to the way of the formation took place.The conventional theory of the formation of the galaxy contends that roughly 12 to 13 billion years ago the Milky Way formed over a relatively short time (about 200 million years) when a spherical cloud of gas collapsed under the pressure of its own gravity into a disc surrounded by a halo. Such a rapid formation of the galaxy would mean that all stars in the halo should be very nearly the same age.However, the astronomer Michael Bolte has found considerable variation in the ages of globular clusters. One of the clusters studied by Bolte is 2 billions years older than most other clusters in the galaxy, while another is 2 billion years younger. A colleague of Bolte contends that the cluster called Palomar 12 is 5 billion years younger than most other globular clusters.To explain the age differences among the globular clusters, astronomers are taking a second look at "renegade"theories. One such newly fashionable theory, first put forward by Richard Larson in the early 1970's, argues that the halo of the Milky Way formed over a period of a billion or more years as hundreds of small gas clouds drifted about, collided, lost orbital energy, and finally collapsed into a centrally condensed elliptical system. Larson's conception of a "lumpy and turbulent" protogalaxy is complemented by computer modeling done in the 1970's by mathematician Alan Toomre, which suggests that closely interacting spiral galaxies could lose enough orbital energy to merge into asingle galaxy.
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It was once assumed that all living things could bedivided into two fundamental and exhaustive categories. Multicellular plants and animals, as well as many unicellular organisms, are eukaryotic-their large, complex cells have a well-formed nucles and many organelles. On the other hand, the true bacteria are prokaryotic cell, which are simple and lack a nucleus. The distinction between eukaryotes and bacteria, initially defined in terms of subcellular structures visible with a microscope, was ultimately carried to the molecular level. Here prokaryotic and eukaryotic cells have many features in common. For instance, they translate genetic information into proteins according to the same type of genetic coding. But even where the molecular processes are the same, the details inthe two forms are different and characteristic of the respective forms. For example, the amino acid sequences of various enzymes tend to be typically prokaryotic or eukaryotic. The differences between the groups and the similarities within each group made it seem certain to most biologists that the tree of life had only two stems. Moreover, arguments pointing out the extent of both structural and functional differences between eukaryotes and true bacteria convinced many biologists that the precursors of the eukaryotes must have diverged from the common ancestor before the bacteria arose.Although much of this picture has been sustained by more recent research, it seems fundamentally wrong in one respect. Among the bacteria, there are organisms that are significantly different both from the cells of eukaryotes and from the true bacteria, and it now appears that there are three stems in the tree of life. [hl:5]New techniques[/hl:5] for determining the molecular sequence of the RNA of organisms have produced evolutionary information about the degree to which organisms are related, the time since they diverged from a common ancestor, and the reconstruction of ancestral versions of genes. These techniques have strongly suggested that although the true bacteria indeed form a large coherent group, certain other bacteria, the archaebacteria, which are also prokaryotes and which resemble true bacteria, represent a distinct evolutionary branch that far antedates the common ancestor of all true bacteria.
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Historians of women's labor in the United States at firstlargely disregarded the story of female service workers-women earning wages in occupations such as salesclerk.domestic servant, and office secretary. These historiansfocused instead on factory work, primarily because itseemed so different from traditional, unpaid "women'swork" in the home, and because the underlying economicforces of industrialism were presumed to be gender-blindand hence emancipatory in effect. Unfortunately, emancipation has been less profound than expected, for not evenindustrial wage labor has escaped continued sex segregation in the workplace.To explain this unfinished revolution in the status ofwomen, historians have recently begun to emphasize theway a prevailing definition of femininity often eterminesthe kinds of work allocated to women, even when suchallocation is inappropriate to new conditions. For instance,early textile-mill entrepreneurs, in justifying women'semployment in wage labor, made much of the assumptionthat women were by nature skillful at detailed tasks andpatient in carrying out repetitive chores; the mill ownersthus imported into the new industrial order hoary stereotypes associated with the homemaking activities theypresumed to have been the purview of women. Becausewomen accepted the more unattractive new industrial tasksmore readily than did men, such jobs came to be regardedas female jobs.And employers, who assumed that women's"real" aspirations were for marriage and family life.declined to pay women wages commensurate with those ofmen. Thus many lower-skilled, lower-paid, less secure jobscame to be perceived as "female."More remarkable than the origin has been the persistenceof such sex segregation in twentieth-century industry. Oncean occupation came to be perceived as "female." employersshowed surprisingly little interest in changing that percep-tion, even when higher profits beckoned. And despite theurgent need of the United States during the Second World Warto mobilize its human resources fully, job segregation by sexcharacterized even the most importantwar industries. Moreover, once the war ended, employersquickly returned to men most of the "male" jobs thatwomen had been permitted to master.
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(This passage was written in 1984.)It is now possible to hear a recording of Caruso's singing that is far superior to any made duringhis lifetime. A decades-old way-cylinder recording of this great operatic tenor has been digitized,and the digitized signal has been processed by computer to remove the extraneous sound, or"noise," introduced by the now "ancient" wax-cylinder recording process.Although this digital technique needs improvements, it represents a new and superior way ofrecording and processing sound which overcomes many of the limitations of analog recording. Inanalog recording systems, the original sound is represented as a continuous waveform created byvariations in the sound's amplitude over time. When analog playback systems reproduce thiswaveform, however, they invariably introduce distortions. First, the waveform produced duringplayback differs somewhat from the original waveform. Second, the medium that stores the analogrecording creates noise during playback which gets added to the recorded sounds.Digital recordings, by contrast, reduce the original sound to a series of discrete numbers thatrepresent the sound's waveform. Because the digital playback system "reads" only numbers, anynoise and distortion that may accumulate during storage and manipulation of the digitized signalwill have little effect: as long as the numbers remain recognizable, the original waveform will bereconstructed with little loss in quality. However, because the waveform is continuous, while itsdigital representation is composed of discrete numbers, it is impossible for digital systems to avoidsome distortion. One kind of distortion, called "sampling error," occurs if the sound is sample (i.e.,its amplitude is measured) too infrequently, so that the amplitude changes more than one quantum(the smallest change in amplitude measured by the digital system) between samplings. In effect,the sound is changing too quickly for the system to record it accurately. A second form ofdistortion is "quantizing error," which arises when the amplitude being measured is not a wholenumber of quanta, forcing the digital recorder to round off. Over the long term, these errors arerandom, and the noise produced (a background buzzing) is similar to analog noise except that itonly occurs when recorded sounds are being reproduced.
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Historians have identified two dominant currents in the Russian women's movement of the late tsarist period. "Bourgeois" feminism, so called by its more radical opponents, emphasized "individualist" feminist goals such as access to education, career opportunities, and legal equality. "Socialist" feminists, by contrast, emphasized class, rather than gender, as the principal source of women's inequality and oppression, and socialist revolution, not legal reform, as the only road to emancipation and equality.However, despite antagonism between bourgeois feminists and socialist feminists, the two movements shared certain underlying beliefs. Both regarded paid labor as the principal means by which women might attain emancipation: participation in the workplace and economic self-sufficiency, they believed, would make women socially useful and therefore deserving of equality with men. Both groups also recognized the enormous difficulties women faced when they combined paid labor with motherhood. In fact, at the First All-Russian Women's Congress in 1908, most participants advocated maternity insurance and paid maternity leave, although the intense hostility between some socialists and bourgeois feminists at the Congress made it difficult for them to recognize these areas of agreement. Finally, socialist feminists and most bourgeois feminists concurred in subordinating women's emancipation to what they considered the more important goal of liberating the entire Russian population from political oppression, economic backwardness, and social injustice.
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Colonial historian David Allen's intensive study of five communities in seventeenth-century Massachusetts is a model of meticulous scholarship on the detailed microcosmic level, and is convincing up to a point. Allen suggests that much more coherence and direct continuity existed between English and colonial agricultural practices and administrative organization than other historians have suggested. However, he overstates his case with the declaration that he has proved "the remarkable extent to which diversity in New England local institutions was directly imitative of regional differences in the mother country.Such an assertion ignores critical differences between seventeenth—century England and New England. First, England was overcrowded and land-hungry; New England was sparsely populated and labor-hungry. Second, England suffered the normal European rate of mortality; New England, especially in the first generation of English colonists, was virtually free from infectious diseases. Third, England had an all-embracing state church; in New England membership in a church was restricted to the elect. Fourth, a high proportion of English villagers lived under paternalistic resident squires; no such class existed in New England. By narrowing his focus to village institutions and ignoring these critical differences, which studies by Greven, Demos, and Lockridge have shown to be so important, Allen has created a somewhat distorted picture of reality.Allen's work is a rather extreme example of the "country community" school of seventeenth-century English history whose intemperate excesses in removing all national issues from the history of that period have been exposed by Professor Clive Holmes. What conclusion can be drawn, for example, from Allen's discovery that Puritan clergy who had come to the colonies from East Anglia were one-third to one-half as likely to return to England by 1660 as were Puritan ministers from western and northern England? We are not told in what way, if at all, [hl:3]this discovery[/hl:3] illuminates historical understanding. Studies of local history have enormously expanded our horizons, but it is a mistake for their authors to conclude that village institutions are all that mattered, simply because their functions are all that the records of village institutions reveal.
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