Maximum likelihood estimation of variance components in a completely random bib design

ABSTRACT

The purposes of this paper are to abstract from a number of articles variance component estimation procedures which can be used for completely random balanced incomplete block designs, to develop an iterated least squares (ITLS) computing algorithm for calculating maximum likelihood estimates, and to compare these procedures by use of simulated experiments. Based on the simulated experiments, the estimated mean square errors of the ITLS estimates are generally less than*those for previously proposed analysis of variance and symmetric sums estimators.     

Social workers' assessments of needs and interventions for adolescents with substance misuse problems,criminal behaviour and mental health difficulties: a vignette study

The aim of the current vignette study was to examine how social workers assess adolescents with substance misuse problems, criminal behaviour and mental health difficulties, and how they make decisions about treatment interventions to reduce these problems. Earlier research has shown lack of knowledge concerning factors and processes that govern assessments and decisions in social work practice. In this anonymously administered survey, social workers in Stockholm, Sweden, were invited to assess fictitious youth issues. We found that social workers recognise the problems and needs of young people, but that they find it harder to link needs to evidence-based interventions. Also, there is a tendency to overrate alleged non-serious problems in the vignettes. We conclude that there is a need for increased knowledge about evidence-based methods and more structured procedures to broaden the basis for decisions.     

A Quality Risk Management Model Approach for Cell Therapy Manufacturing

International regulatory authorities view risk management as an essential production need for the development of innovative, somatic cell‐based therapies in regenerative medicine. The available risk management guidelines, however, provide little guidance on specific risk analysis approaches and procedures applicable in clinical cell therapy manufacturing. This raises a number of problems. Cell manufacturing is a poorly automated process, prone to operator‐introduced variations, and affected by heterogeneity of the processed organs/tissues and lot‐dependent variability of reagent (e.g., collagenase) efficiency. In this study, the principal challenges faced in a cell‐based product manufacturing context (i.e., high dependence on human intervention and absence of reference standards for acceptable risk levels) are identified and addressed, and a risk management model approach applicable to manufacturing of cells for clinical use is described for the first time. The use of the heuristic and pseudo‐quantitative failure mode and effect analysis/failure mode and critical effect analysis risk analysis technique associated with direct estimation of severity, occurrence, and detection is, in this specific context, as effective as, but more efficient than, the analytic hierarchy process. Moreover, a severity/occurrence matrix and Pareto analysis can be successfully adopted to identify priority failure modes on which to act to mitigate risks. The application of this approach to clinical cell therapy manufacturing in regenerative medicine is also discussed.     

Social Development in Hong Kong: Development Issues Identified by Social Development Index (SDI)

Surviving the aftermaths of the Asian Financial Crisis and SARS in 2003, Hong Kong’s economy has re-gained its momentum and its economic growth has been quite remarkable too in recent few years. Nevertheless, as reflected by the Social Development Index (SDI), economic growth in Hong Kong does not seem to have benefited the people of the city at large as we see social qualities such as cohesion, security, equity, and empowerment are gradually eroded. This paper aims to summarize the current state of social development in Hong Kong based on the SDI-2008 and identify the major social, political and economic challenges that are confronted by Hong Kong. Based on the findings, a range of policy options proposed for promoting a more balanced approach to social and economic development are discussed. The article illustrates the utility of social indicators research such as the SDI in assessing quality of life and assisting related social planning initiatives in Asian communities such as Hong Kong.     

Prediction based classification for longitudinal biomarkers

Assessment of circulating CD4 count change over time in HIV-infected subjects on antiretroviral therapy (ART) is a central component of disease monitoring. The increasing number of HIV-infected subjects starting therapy and the limited capacity to support CD4 count testing within resource-limited settings have fueled interest in identifying correlates of CD4 count change such as total lymphocyte count, among others. The application of modeling techniques will be essential to this endeavor due to the typically non-linear CD4 trajectory over time and the multiple input variables necessary for capturing CD4 variability. We propose a prediction based classification approach that involves first stage modeling and subsequent classification based on clinically meaningful thresholds. This approach draws on existing analytical methods described in the receiver operating characteristic curve literature while presenting an extension for handling a continuous outcome. Application of this method to an independent test sample results in greater than 98% positive predictive value for CD4 count change. The prediction algorithm is derived based on a cohort of n = 270 HIV-1 infected individuals from the Royal Free Hospital, London who were followed for up to three years from initiation of ART. A test sample comprised of n = 72 individuals from Philadelphia and followed for a similar length of time is used for validation. Results suggest that this approach may be a useful tool for prioritizing limited laboratory resources for CD4 testing after subjects start antiretroviral therapy.