A Joint Modeling Approach for Longitudinal Outcomes and Non-ignorable Dropout under Population Heterogeneity in Mental Health Studies

The paper proposes a joint mixture model to model non-ignorable drop-out in longitudinal cohort studies of mental health outcomes. The model combines a (non)-linear growth curve model for the time-dependent outcomes and a discrete-time survival model for the drop-out with random effects shared by the two sub-models. The mixture part of the model takes into account population heterogeneity by accounting for latent subgroups of the shared effects that may lead to different patterns for the growth and the drop-out tendency. A simulation study shows that the joint mixture model provides greater precision in estimating the average slope and covariance matrix of random effects. We illustrate its benefits with data from a longitudinal cohort study that characterizes depression symptoms over time yet is hindered by non-trivial participant drop-out.KEYWORDS: Latent growth curve, MNAR drop-out, survival analysis, finite mixture model, mental health     

Improved Transferability of Data‐Driven Damage Models Through Sample Selection Bias Correction

Damage models for natural hazards are used for decision making on reducing and transferring risk. The damage estimates from these models depend on many variables and their complex sometimes nonlinear relationships with the damage. In recent years, data‐driven modeling techniques have been used to capture those relationships. The available data to build such models are often limited. Therefore, in practice it is usually necessary to transfer models to a different context. In this article, we show that this implies the samples used to build the model are often not fully representative for the situation where they need to be applied on, which leads to a “sample selection bias.” In this article, we enhance data‐driven damage models by applying methods, not previously applied to damage modeling, to correct for this bias before the machine learning (ML) models are trained. We demonstrate this with case studies on flooding in Europe, and typhoon wind damage in the Philippines. Two sample selection bias correction methods from the ML literature are applied and one of these methods is also adjusted to our problem. These three methods are combined with stochastic generation of synthetic damage data. We demonstrate that for both case studies, the sample selection bias correction techniques reduce model errors, especially for the mean bias error this reduction can be larger than 30%. The novel combination with stochastic data generation seems to enhance these techniques. This shows that sample selection bias correction methods are beneficial for damage model transfer.     

Working Adults and Personal Business Ethics in South East Asia: a Comparative Study in Thailand and Vietnam

Global leaders and managers have been facing new challenges in the twenty-first century since globalization has created a much more integrated and borderless business environment. One of the key issues that they constantly deal with is business ethics. The global economy has made ethical issues become more complex and challenging. Businesses nowadays face urgent demands to act ethically and responsibly. In order for global leaders and managers to manage such a cultural diverse and complex workforce, they must have the ability to understand these complex issues and act ethically. They also need to possess adequate leadership skills to lead an ethical organization in a multinational environment. Thus, understanding and recognizing the cultural differences as well as the ethical standards of people in different countries are critical to the success of global leaders and managers. The purpose of this study is to investigate the perception of working professionals on business ethics in the two high-context cultures in South East Asia: Thailand and Vietnam. Using the Univariate Analysis of Variance method and adopting the widely-used Clark and Clark’s Personal Business Ethics Scores (PBES) measure, this study will compare the level of ethical maturity of the respondents based on a variety of variables including gender, business law course taken, code of conduct, ethics training, and government work experience. The authors will provide a thorough literature review on business ethics as well as the current ethical issues, i.e., bribery and corruption, in the two countries, together with practical suggestions and implications for educators, managers, and employees.     

Reshaping state/local communities relations in Tunisia: The socio-cultural and institutional challenges of the decentralization project

International development agencies believe that by adopting institutional reforms based on the best practices that have proved effective elsewhere, so-called « developing countries » could take their places in the globalised economy. Based on a case study carried out on the implementation challenges of a decentralization project in Tunisia, I will argue by using an interpretive approach that this thesis is not sustained. This article shows that institutions cannot be reduced to their technical functions but that they are based on particular collective imaginaries that ground what is legitimate or not and structure the relationship of individuals to power and the meaning given to their actions. It encourages the consideration of cultural framework of meaning; these local cultural references structure the governance modalities of a society, understood in terms of the modalities of exercise of power in a given group (state, company, local authority, etc.). It advocates the necessity to move from a technic-prone approach in the implementation of institutional changes towards a socio-cultural approach that integrates the local expectations of what “good governance” should be and on which depends the legitimacy of institutions and their appropriation by local populations.     

A comparative study of the searching efficiencies of a parasite and a hyperparasite

Summary The searching efficiencies of a primary parasite (Diaeretiella rapae (McIntosh)) and a hyperparasite (Alloxysta brassicae (Ash.)) were investigated and compared. In both species, at all parasite densities, there was a curvilinear relationship (P<0.001) between the number of hosts parasitised and the host density. A linear regression (loga=logQ−m logP) was fitted for log area of discovery against log parasite density (P<0.001). The area of discovery for its immediate (i.e. primary) host (viz.Diaeretiella for the hyperparasite and aphid forDiaeretiella) is lower in the hyperparasite than in the primary parasite. InDiaeretialla both the searching efficiency and the mutual interference constant increased (but not significantly,P>0.05) in the presence of its males.     

The Ecology of Suicide in an Australian Metropolis: The Case of Sydney

The ecological patterns of suicide in metropolitan Sydney are described and policy recommendations made. Some inferences about the association of urbanization with suicide are suggested.