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.     

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.     

Ownership Strategy and Foreign Affiliate Performance in Multinational Family Business Groups: A Double-edged Sword

We argue that ownership strategies can be a double edged sword for multinational family business groups from emerging economies and the performance of their affiliates located abroad. We test an integrated framework based on internalization and agency theory on a longitudinal dataset of multinational family business groups from Taiwan. We find evidence for the contingent impact of cultural differences and family management on the association between ownership strategy and affiliate performance. While direct ownership is seen as offering more control over the affiliate, we show that this comes at a performance cost for affiliates in culturally different host countries and affiliates under family management. Indirect ownership seems to be one way to positively influence affiliate performance in culturally distant countries, but seems not to be contingent on family management utilization.     

Approximation Algorithms in Batch Processing

A polynomial approximation scheme for minimizing makespan in a batch processing system under dynamic job arrivals is presented. A lower bound of on the competitive ratio of any on-line algorithm is proved. This is matched by an on-line algorithm for the special case of unbounded machine capacity.     

Estimating the underlying change in unemployment in the UK

By setting up a suitable time series model in state space form, the latest estimate of the underlying current change in a series may be computed by the Kalman filter. This may be done even if the observations are only available in a time-aggregated form subject to survey sampling error. A related series, possibly observed more frequently, may be used to improve the estimate of change further. The paper applies these techniques to the important problem of estimating the underlying monthly change in unemployment in the UK measured according to the definition of the International Labour Organisation by the Labour Force Survey. The fitted models suggest a reduction in root-mean-squared error of around 10% over a simple estimate based on differences if a univariate model is used and a further reduction of 50% if information on claimant counts is taken into account. With seasonally unadjusted data, the bivariate model offers a gain of roughly 40% over the use of annual differences. For both adjusted and unadjusted data, there is a further gain of around 10% if the next month's figure on claimant counts is used. The method preferred is based on a bivariate model with unadjusted data. If the next month's claimant count is known, the root-mean-squared error for the estimate of change is just over 10000.     

Cox regression for current status data with mismeasured covariates

Covariate measurement error problems have been extensively studied in the context of right‐censored data but less so for current status data. Motivated by the zebrafish basal cell carcinoma (BCC) study, where the occurrence time of BCC was only known to lie before or after a sacrifice time and where the covariate (Sonic hedgehog expression) was measured with error, the authors describe a semiparametric maximum likelihood method for analyzing current status data with mismeasured covariates under the proportional hazards model. They show that the estimator of the regression coefficient is asymptotically normal and efficient and that the profile likelihood ratio test is asymptotically Chi‐squared. They also provide an easily implemented algorithm for computing the estimators. They evaluate their method through simulation studies, and illustrate it with a real data example. The Canadian Journal of Statistics 39: 73–88; 2011 © 2011 Statistical Society of Canada     

Determinants of fertility control in Korea

The objective of this study is to examine the socioeconomic and intervening determinants of fertility control in Korea. The conceptual framework applied here is based on the synthesis framework of fertility control developed by Easterlin and Crimmins. The data came from the 1974 Korean National Family Survey, which was conducted as part of the World Fertility Survey. The study focuses on the relative importance of the socioeconomic factors and intervening variables in the determination of fertility control. The most interesting finding is that there are only small differentials in fertility control by socioeconomic factors. The analysis emphasizes the importance of examining the determinants of fertility control in terms of the intervening variables, which include the components of natural fertility, desired family size, and costs of fertility control. These intervening variables provide general support for the theoretical predictions. Moreover, most of the coefficients for these variables are statistically significant at the .05 level. The analysis also shows that motivation for fertility control is an important factor in determining use of fertility control.