Finite mixture models with concomitant information: assessing diagnostic criteria for diabetes

The World Health Organization (WHO) diagnostic criteria for diabetes mellitus were determined in part by evidence that in some populations the plasma glucose level 2 h after an oral glucose load is a mixture of two distinct distributions. We present a finite mixture model that allows the two component densities to be generalized linear models and the mixture probability to be a logistic regression model. The model allows us to estimate the prevalence of diabetes and sensitivity and specificity of the diagnostic criteria as a function of covariates and to estimate them in the absence of an external standard. Sensitivity is the probability that a test indicates disease conditionally on disease being present. Specificity is the probability that a test indicates no disease conditionally on no disease being present. We obtained maximum likelihood estimates via the EM algorithm and derived the standard errors from the information matrix and by the bootstrap. In the application to data from the diabetes in Egypt project a two-component mixture model fits well and the two components are interpreted as normal and diabetes. The means and variances are similar to results found in other populations. The minimum misclassification cutpoints decrease with age, are lower in urban areas and are higher in rural areas than the 200 mg dl^-1 cutpoint recommended by the WHO. These differences are modest and our results generally support the WHO criterion. Our methods allow the direct inclusion of concomitant data whereas past analyses were based on partitioning the data.     

GENDER, EARNINGS, AND THE ENGLISH SKILL ACQUISITION OF HISPANIC WORKERS IN THE UNITED STATES

Using the 1980 and 1990 Public Use Microdata Samples, we find that labor market outcomes associated with English proficiency vary with respect to gender. For example, a synthetic cohort analysis provides evidence of gender-related differences in Hispanic workers' English skill acquisition. Moreover, we observe that Hispanic women face a lower English deficiency earnings penalty that rises more sharply with education than the penalty obtained by their otherwise similar male peers. Finally, English fluency appears to serve as a stronger occupational sorting mechanism for women than men. ( JEL J3, J1)     

Practicing managed care in the academic medical center

The purpose of this article is to outline the contrasts between the traditional AMC and an organization oriented toward the delivery of population-based managed care. Academic medical centers differ from one another considerably in the extent to which they serve as quaternary care community resources, the degree to which they emphasize primary care in training and care delivery, and the amount of research undertaken. Nor is there a single organizational structure for managed care; successful managed care is practices in IPAs, multispecialty groups, PHOs, and staff-model HMOs. Nonetheless, the contrasts outlined here between AMCs and managed care organizations (MCOs) are valid in most cases.     

The implementation of the healthy cities project in developing countries: lessons from Chittagong

The Chittagong Healthy City Project was carried out in late 1994 in Chittagong, Bangladesh. This paper presents findings of an evaluation of the project based upon internationally generated process indicators related to the institutional aspects of the project. The following issues are discussed with regard to project implementation: the institutional organization of local authorities, institutions' conceptual understanding of the project, formal insertion of the project into public authorities' activities, institutional leadership of the project, central-local relations, the lack of interministerial coordination, the project's office, international projects, and community organization. Giving consideration to these issues may help program planners detect problems in forthcoming projects prior to their implementation.     

From the 30s to the 60s: The folk music revival in the United States

Conclusion Woody Guthrie's ashes were spread by the wind over the water from a Coney Island, New York pier a few days after he died on Oct. 3, 1967. His wife and children, including his 19-year-old son Arlo, were present as America's greatest folksinger was laid to rest. One of the last things Woody heard before he died was Arlo's recorded voice singing the draft-dodging tale of Alice's restaurant. He must have sensed that the spirit had been passed on. Woody Guthrie died just as the second great wave of popular interest in American folk music was coming to an end. Alice's Restaurant was in many ways one of its last echoes. The symbolism could not have been more poignant. At the center of the first folk revival, Woody Guthrie was a vital source of inspiration for the second.The new generation of singer-songwriters who marked the second wave was largely composed of those with at least some contact with the new mass higher education and those multi-versities that were built to dispense it. They were neither members of a déclassé elite, as could be said of Charles and Pete Seeger and John and Alan Lomax, nor were they authentic folk singers, like Woody Guthrie. Nor could they be. By the 1960s, the conditions that had created the possibility for the first wave of the movement had been irretrievably altered. After the Second World War, with a postwar economic expansion and population explosion under way, America was a different place. Besides, the first folk revival had already claimed authenticity as its own. For the most part, if there was any aspiration toward authenticity amongst the topical singer-songwriters (those in New York City in any case), it was to be as close a copy of the first generation, Guthrie and Seeger, as possible. Purism was the second wave's answer to the authenticity of the first.Being part of an expanding generation of white, college-educated youths affected the form and content of the music that characterized the second wave. The most obvious aspect of this was the arena of performance and the audience who filled it. Gone were the union halls, the singing in working-class bars and beerhalls and at Party functions, all of which had characterized the first wave. These were replaced first by coffee shops and small clubs, either in Greenwich Village or those surrounding college campuses. The forays into the South in support of the civil-rights movement were for the most part short-lived and highly symbolic, not to say self-serving. The real mass audience arrived with the antiwar activity and was largely university centered.It was also this audience that filled the auditoriums and concert halls for the more obviously commercial performances by the singer-songwriters of the second wave. This overlapping public provided the grounds for a new mass market in folk music. Peter, Paul, and Mary, who sang in front of many mass demonstrations in protest against the war in Vietnam or in support of civil rights, were, although they saw themselves as carrying on in the spirit of the Weavers, an entirely commercial creation. In the article from the East Village Other cited above, written just after the first big concert in America against the war in Vietnam, Izzy Young angrily notes that everybody was a part of it except the people managed by Albert Grossman - Peter, Paul and Mary, and Bob Dylan. When the war in Vietnam became popular, three years later, Peter, Paul and Mary flew down to Washington, D.C. to take their place in front of the cameras.Commercial rationality was much more a factor in defining the second folk revival than the first. The possibilities were greater and the structure of the music industry was different. With a new mass market still in the process of formation and thus unspecified in terms of taste, the larger record companies could afford to take a liberal attitude and to include under their label, all the revolutionaries, as Columbia Records proudly announced in its contemporary advertising. Commercial possibilities thus were more important in shaping the musical form and content of second folk revival than politics, which were so central to the first. As opposed to the old left, the new left was a loosely organized contingent of organizations and groups with little coordination between them. In fact, many if not most of the organizations were ad hoc committees formed for a specific strike or demonstration. No one group was thus in a position to exert ideological hegemony. Following from this, at least during the period under discussion, there was little political dogmatism to be found. With no powerful organization to impose it, there was no clear political line to defend and thus to sing about. Even the notion of the people, so central to the first folk revival, was relatively absent in the second. Who were the people addressed? Certainly not the working class or even the common man. I am just a student, Sir, I only want to learn, sang Phil Ochs.During the second folk revival, the people had become the silent majority, the province of the conservative right. Neither in music nor in politics did the new left make many attempts to reach the common man in the street. The people had been massified, according to new left theory, and in the new one-dimensional mass society the grounds of political and social identity were always shifting. Besides, country music had already established itself as the musical genre of the rural, southern, western and white, common man. From a commercial point of view, there was little need to look for authenticity or the people; the market was sufficiently large and getting larger as more and more young people entered the institutions of higher education. Politically, this was not a serious problem either, as long as the aim was not revolution as it had been for the old left. It was sufficient, then, to address the masses of youngsters gathering together at institutions of higher education. If there was a revolution at foot, this was it.While the first wave practically had to invent folk music, the second could draw on the reservoir of public culture that to a large extent resulted from this invention. The networks and institutional support provided by the old left and the personal authority of a figure like Alan Lomax made possible the imposition of rather strict criteria for determining in what exactly folk music consisted. Neither networks nor gatekeepers were so determinate to the second wave. With the folksong and folksinger already invented, the new generation could pick and choose from a rather wide range of options. In addition, by the time the new left and the topical-song movement achieved at least a semblance of cohesion, folk music was already institutionally supported by radical entrepreneurs like Izzy Young and the more commercial recording industry. There were, thus, strong institutional bases for folk music outside of politics. Politics, in other words, was not the only game in town. But neither was commerce. The civil-rights movement and the new social movements that developed out of it opened for a short period a space, a public arena, in which the idea of folk music could be reinvented anew. Within this space the traditions constituted during the first wave of folk revival were experimented with and modified in light of the new social and historical context. America was not the same place in the 1960s as it had been in the 1930s and neither could its folk music be. The actors, the setting, and the songs were all different, yet still the same.In attempting to account for both this continuity and change in the two waves of folk revival we have drawn from both the cognitive approach to the study of social movements, which calls attention to the creative role of social-movement actors in the production of knowledge, and the production of culture perspective, which highlights the effects of institutional arrangements in the production of cultural goods. From the former, we have focused on the changing character of movement intellectuals, those to whom Ralph Rinzler in the epigraph that begins this article gave special place; from the latter, we have noted how, among other things, the changing nature of the recording industry helped recast the folk music revival. We hope that the foregoing has demonstrated that in combining these approaches, as well as areas of research interest, we have uncovered aspects of the folk revival others may have missed.     

Characterizations,length-biasing,and infinite divisibility

SupposeL(X) is the law of a positive random variableX, andZ is positive and independent ofX. Admissible solution pairs (L(X),L(Z)) are sought for the in-law equation $\hat X \cong X o Z$ °Z, where $L\left( {\hat X} \right)$ is a weighted law constructed fromL(X), and ° is a binary operation which in some sense is increasing. The class of weights includes length biasing of arbitrary order. When ° is addition and the weighting is ordinary length biasing, the class of admissibleL(X) comprises the positive infinitely divisible laws. Examples are given subsuming all known specific cases. Some extensions for general order of length-biasing are discussed.     

Changes in physician and non-physician relationships

At the end of World War II, one-third of the nation's hospital administrators were physicians. During the 1950's through the mid-1980's a new breed of masters'level administrator, with well-honed coordinating skills, orchestrated a major expansion of new programs, services, and facilities. With the advent of the Medicare prospective payment system (PPS), more governing boards restructured their administrative staffs with corporate titles. Meanwhile, physicians sensed that trustees were becoming far more concerned with bottom line performance to repay a mounting debt that hospitals had incurred to remain technologically competitive. Since mergers and integrated health systems by themselves will be unable to generate significant operating efficiencies, governing boards will be forced to change direction and shift back to recruiting physicians as their CEOs or in other senior positions to assure themselves of the clinical leadership required to implement the managed care concepts of reducing utilization and cost, and simultaneously enhancing quality of patient care.     

An Exploration of the Meaning and Consequences of Workaholism

Although much has been written aboutworkaholism, rigorous research andtheoretical development on the topic is in its infancy.We integrate literature from multiple disciplines andoffer a definition of workaholic behavior. We identify three types ofworkaholic behavior patterns: compulsive-dependent,perfectionist, and achievement-oriented workaholism. Apreliminary model is proposed; it identifies potential linkages between each type of workaholismpattern and important outcomes such as performance, joband life satisfaction, and turnover. Specificpropositions for future research are articulated. Weconclude that, depending on the type of workaholicbehavior pattern, workaholism can be good or bad, andits consequences may be experienced or evaluateddifferently by individuals, organizations, and societyat large. Researchers and managers should avoidmaking judgments about the positive or negative effectsof workaholism until more carefully controlled researchhas been published.