Nonparametric Shrinkage Estimation for Aalen's Additive Hazards Model

Aalen's nonparametric additive model in which the regression coefficients are assumed to be unspecified functions of time is a flexible alternative to Cox's proportional hazards model when the proportionality assumption is in doubt. In this paper, we incorporate a general linear hypothesis into the estimation of the time‐varying regression coefficients. We combine unrestricted least squares estimators and estimators that are restricted by the linear hypothesis and produce James‐Stein‐type shrinkage estimators of the regression coefficients. We develop the asymptotic joint distribution of such restricted and unrestricted estimators and use this to study the relative performance of the proposed estimators via their integrated asymptotic distributional risks. We conduct Monte Carlo simulations to examine the relative performance of the estimators in terms of their integrated mean square errors. We also compare the performance of the proposed estimators with a recently devised LASSO estimator as well as with ridge‐type estimators both via simulations and data on the survival of primary billiary cirhosis patients.     

State transition modeling of complex monitored health data

This article considers the analysis of complex monitored health data, where often one or several signals are reflecting the current health status that can be represented by a finite number of states, in addition to a set of covariates. In particular, we consider a novel application of a non-parametric state intensity regression method in order to study time-dependent effects of covariates on the state transition intensities. The method can handle baseline, time varying as well as dynamic covariates. Because of the non-parametric nature, the method can handle different data types and challenges under minimal assumptions. If the signal that is reflecting the current health status is of continuous nature, we propose the application of a weighted median and a hysteresis filter as data pre-processing steps in order to facilitate robust analysis. In intensity regression, covariates can be aggregated by a suitable functional form over a time history window. We propose to study the estimated cumulative regression parameters for different choices of the time history window in order to investigate short- and long-term effects of the given covariates. The proposed framework is discussed and applied to resuscitation data of newborns collected in Tanzania.     

Active Ageing: Social and Cultural Integration of Older Turkish Alevi Refugees in London

Ageing of migrants in Europe has become an important policy issue, especially within the context of health inequalities and increasing health care costs. Based on in-depth interviews with older Alevi/Kurdish refugees in London, we explore the cumulative impact of difficult migration trajectories on the experience of ageing. The findings highlight the important role of cultural capital and transnational ties throughout the refugees’ migration journeys and particularly at old age. However, the study indicates the double edge impact of strong ‘solidarity’ bonds, increasing isolation at old age due to lack of accumulation of capital and knowledge, particularly language, which are important in accessing health and social care services at old age.     

Evaluating modified generalized information criterion in presence of multicollinearity

When there are many explanatory variables in the regression model, there is a chance that some of these are intercorrelated. This is where the problem of multicollinearity creeps in due to which precision and accuracy of the coefficients is marred, and the quest to find the best model becomes tedious. To tackle such a situation, Model selection criteria are applied for selecting the best model that fits the data. Current study focuses on the evaluation of the four unmodified and four modified versions of generalized information criteria—Akaike Information Criterion, Schwarz's Bayes Information Criteria, Hannan-Quinn Information Criterion, and Akaike Information Criterion corrected for small samples. A simulation study using SAS software was carried out in order to compare the unmodified and modified versions of the generalized information criteria and to discover the best version amongst the four modified model selection criteria, for identifying the best model, when the collinearity assumption is violated. For the proposed simulation, two samples of size 50 and 100, for three explanatory variables X₁, X₂, and X₃, are drawn from Normal distribution. Two situations of collinearity violations between X₁ and X₂ are looked into, first when ρ = 0.6 and second when ρ = 0.8. The outcomes of the simulations are displayed in the tables along with visual representations. The results revealed that modified versions of the generalized information criteria are more sensitive in identifying models marred with high multicollinearity as compared to the unmodified generalized information criteria.     

Migration,gender and low-paid work: on migrant men’s entry dynamics into the feminised social care work in the UK

The literature on workers in gender atypical occupations has been dominated by a focus on women doing men’s work. Much less attention has been paid to men in women’s work, and even less to the impact of migration. Based on 28 in-depth interviews with migrant men having experiences of working in hands-on social care in England, this article is a contribution to the understanding of migrant men’s entry dynamics into a female-dominated occupation. Focusing on migrant life experiences, it discusses how they actively engage in three entry dynamics: (1) facing barriers and negotiating them, (2) ‘stumbling upon’ women’s work, then developing compensating strategies and (3) migratory/temporary settling into the sector. The article suggests a theory about lifelong ‘travelling’ when entering women’s work: a continuing process of negotiating work options within a specific historical sector context, the intersection of gender and migration being part of this.     

Trade-off between quoted lead time and price

In a make-to-order environment, lead time and price can play a crucial role in determining the financial success of a firm. Their importance increases when demand is sensitive to the quoted lead time and price. A model is presented which uses the quoted lead time and price as a mechanism to determine the optimal demand level. The relationships between the model parameters and their impacts on the firm's profit is also analysed. In addition, the effect of the number of job requests, and the mean processing time are examined. Based on the results presented in this paper, there is clear indication that the firm's profit is sensitive to the inventory holding rate, and that the inventory holding cost component is redundant in the presence of a tardiness cost component.     

An Assessment of Sheltered Housing Design in Belfast,Northern Ireland

This article presents a UK-based research that has studied the existing sheltered or assisted living housing population and its future housing options and preferences. This meets an identified need to know and understand users' needs and requirements in much more detail that outlines what is liked and disliked by older people about sheltered housing, so that those who plan and design such housing can be aware of their views. The study also sought to understand the architects' challenges in designing and adapting this type of housing. The sheltered housing managed by housing associations in Belfast, Northern Ireland, was assessed through a series of site visits, structured interviews, and a focus group with stakeholders. Findings revealed older users' keen interest in participating in their housing needs assessment, identified building design concerns and provided recommendations for potential design guidelines.     

Emploi des jeunes et inégalité des chances: en quoi le monde arabe est-il différent?

Le marché du travail du Moyen-Orient et de l'Afrique du Nord se caractérise par un chômage des jeunes généralisé et par un nombre disproportionné de chômeurs parmi les nouveaux diplômés. À partir des enquětes du BIT sur le passage de l'école à la vie active menées en Égypte, Jordanie et Tunisie, les auteurs regardent si cela tient à l'inégalité des chances ou à des caractéristiques structurelles induisant des discordances entre offre et demande de travail. Les principales explications seraient le faible nombre d'emplois qualifiés disponibles et le peu de valeur accordée aux qualifications acquises dans le système de formation professionnelle.     

Training and organizational commitment: exploring the moderating role of goal orientation in the Lebanese context

In this study, we investigated the impact of organizational training on organizational commitment and whether goal orientation moderates the relationship between training and commitment. The sample consisted of 124 employees from different industries in the country of Lebanon. Multiple regression and hierarchical moderated regression were used to test hypotheses. The results of the analysis showed that training has a significant effect on organizational commitment. Moderation analysis showed that the relationship between training and affective commitment was stronger for individuals who had higher levels of learning goal orientation. Performance goal orientation failed to moderate the relationship between training and affective commitment. Ultimately, this suggests that advanced training offered to individuals with performance goal orientations may not necessarily increase their commitment to their employer, in contrast to individuals with learning goal orientations. Theoretical and management implications in the context of Lebanon are proposed.