Latent class logistic regression: application to marijuana use and attitudes among high school seniors

Summary.  Analysing the use of marijuana is challenging in part because there is no widely accepted single measure of individual use. Similarly, there is no single response variable that effectively captures attitudes toward its social and moral acceptability. One approach is to view the joint distribution of multiple use and attitude indicators as a mixture of latent classes. Pooling items from the annual 'Monitoring the future' surveys of American high school seniors from 1977 to 2001, we find that marijuana use and attitudes are well summarized by a four-class model. Secular trends in class prevalences over this period reveal major shifts in use and attitudes. Applying a multinomial logistic model to the latent response, we investigate how class membership relates to demographic and life style factors, political beliefs and religiosity over time. Inferences about the parameters of the latent class logistic model are obtained by a combination of maximum likelihood and Bayesian techniques.     

The Consequences of Migration to the United States for Short-Term Changes in the Health of Mexican Immigrants

Although many studies have attempted to examine the consequences of Mexico-U.S. migration for Mexican immigrants’ health, few have had adequate data to generate the appropriate comparisons. In this article, we use data from two waves of the Mexican Family Life Survey (MxFLS) to compare the health of current migrants from Mexico with those of earlier migrants and nonmigrants. Because the longitudinal data permit us to examine short-term changes in health status subsequent to the baseline survey for current migrants and for Mexican residents, as well as to control for the potential health selectivity of migrants, the results provide a clearer picture of the consequences of immigration for Mexican migrant health than have previous studies. Our findings demonstrate that current migrants are more likely to experience recent changes in health status—both improvements and declines—than either earlier migrants or nonmigrants. The net effect, however, is a decline in health for current migrants: compared with never migrants, the health of current migrants is much more likely to have declined in the year or two since migration and not significantly more likely to have improved. Thus, it appears that the migration process itself and/or the experiences of the immediate post-migration period detrimentally affect Mexican immigrants’ health.     

Comparing the Survival of Two Groups with an Intermediate Clinical Event

Consider a subject entered on a clinicaltrial in which the major endpoint is a time metric such as deathor time to reach a well defined event. During the observationalperiod the subject may experience an intermediate clinical event.The intermediate clinical event may induce a change in the survivaldistribution. We consider models for the one and two sample problem.The model for the one sample problem enables one to test if theoccurrence of the intermediate event changed the survival distribution.This models provides a way of carrying out non-randomized clinicaltrial to determine if a therapy has benefit. The two sample problemconsiders testing if the probability distributions, with andwithout an intermediate event, are the same. Statistical testsare derived using a semi-Markov or a time dependent mixture model.Simulation studies are carried out to compare these new procedureswith the log rank, stratified log rank and landmark tests. Thenew tests appear to have uniformly greater power than these competitortests. The methods are applied to a randomized clinical trialcarried out by the Aids Clinical Trial Group (ACTG) which comparedlow versus high doses of zidovudine (AZT).     

Imagining Social Work: A Qualitative Study of Students' Perspectives on Social Work in China

Social work education in China has expanded rapidly since it was reintroduced in 1988. This has led to a growing body of English language literature on the development of social work education in China. However, thus far, this literature lacks an empirical foundation and little research on students' perspectives has been done. To fill this gap, this paper reports on a qualitative study of a group of graduating social work students (n = 32) from four social work programmes in Jinan, the provincial capital of the Shandong Province. Three major findings are reported. Firstly, the students liken their social work learning experience to a roller coaster ride with many ups and downs. Secondly, the cultural compatibility of western social work in China has not yet been conclusively established, while an ‘indigenized’ social work needs to be compatible with Chinese family values, referred to as ‘familism’ in direct Chinese to English translation, and with the dominant socialist political ideology. Thirdly, the future of social work is bright given increasing government support for its development.     

Public Documents and Legislation: The South Australian Juvenile Courts Act, 1971, and Community Welfare Act, 1972

Abstract

This study of social work practice and disability follows the history of two fields of disability: mental illness and intellectual disability. Of particular interest are two key policy influences in the disability sector, deinstitutionalisation and normalisation. The extent to which deinstitutionalisation and normalisation have brought real benefit to people with disabilities is examined from social workers' perspectives. The implementation of these policies and practices on the daily work of social workers is discussed. This research indicates that social work practice in these two fields involves significantly different foci and approach. The study found that the similarities and differences between the two fields of practice are influenced by the historical and contemporary developments in the care and control of people with disabilities.     

Public relations aspects of brand attitudes and customer activity

Featuring the role of public relations in brand equity research and best practices, this study investigates how product, non-product, and customer–business relationship attributes affect customer-based brand equity (i.e., brand attitudes and customer activity). Analysis reveals customer–business relationships are central to a causal model linking evaluation (brand attitudes) and activation/motivations (customer activity). Findings demonstrate that for service businesses (e.g., banks), customer–business relationships are the primary, rather than minor, predictor of brand equity. These findings demonstrate how public relations scholarship and practice plays a central rather than peripheral role in customer satisfaction.     

The Critical Role of Ocean Container Transport in Global Supply Chain Performance

With supply chains distributed across global markets, ocean container transport now is a critical element of any such supply chain. We identify key characteristics of ocean container transport from a supply chain perspective. We find that unlike continental (road) transport, service offerings tend to be consolidated in few service providers, and a strong focus exists on maximization of capital intensive resources. Based on the characteristics of ocean container transport as part of global supply chains, we list a number of relevant and challenging research areas and associated questions.     

A note on the article “Economic order quantity with trade credit financing for non-decreasing demand”

This note not only indicates incompleteness of both Theorems 2 and 3 in Teng et al. (2012) [1] but also presents correct modifications for them.     

Managing lean capabilities through flexible workforce development: a process and framework

Many firms today are employing temporary contractual workers in order to help them to stay lean and flexible. The benefit of this approach is that the process of layoff is much easier. Thus, an emerging issue arises here, on how can firms manage and train temporary workers effectively? The core of lean adoption is through people, to have workers buy into the ideas and be part of the overall initiative. There is very little guidance available on how to deal with contractual workers who have less motivation and commitment to the firm given that they are only employed on a temporary basis. This article proposes a framework and process to assist firms in managing and training temporary workers to improve the efficiency and effectiveness of the implementation of lean improvement initiatives.     

SERVICE TYPOLOGIES: A STATE OF THE ART SURVEY

Services comprise an ever-expanding source of employment in the world's economies and are of significant interest to both academicians and practitioners. In this study, historical perspectives from which to view service typologies are provided and four decades of service typologies are chronicled. The interest in services demonstrated by academicians is tracked over time as are the purposes for which typologies have been developed. A unified schematic representation of services is developed in which the common themes underlying service typology development are identified from both a macro and micro level. Based on this study, areas for future research are identified.