Robust Bayesian nonlinear mixed‐effects modeling of time to positivity in tuberculosis trials

Early phase 2 tuberculosis (TB) trials are conducted to characterize the early bactericidal activity (EBA) of anti‐TB drugs. The EBA of anti‐TB drugs has conventionally been calculated as the rate of decline in colony forming unit (CFU) count during the first 14 days of treatment. The measurement of CFU count, however, is expensive and prone to contamination. Alternatively to CFU count, time to positivity (TTP), which is a potential biomarker for long‐term efficacy of anti‐TB drugs, can be used to characterize EBA. The current Bayesian nonlinear mixed‐effects (NLME) regression model for TTP data, however, lacks robustness to gross outliers that often are present in the data. The conventional way of handling such outliers involves their identification by visual inspection and subsequent exclusion from the analysis. However, this process can be questioned because of its subjective nature. For this reason, we fitted robust versions of the Bayesian nonlinear mixed‐effects regression model to a wide range of TTP datasets. The performance of the explored models was assessed through model comparison statistics and a simulation study. We conclude that fitting a robust model to TTP data obviates the need for explicit identification and subsequent “deletion” of outliers but ensures that gross outliers exert no undue influence on model fits. We recommend that the current practice of fitting conventional normal theory models be abandoned in favor of fitting robust models to TTP data.     

Social mobility and demand for redistribution in Europe: a comparative analysis

The literature on preferences for redistribution has paid little attention to the effect of social mobility on the demand for redistribution and no systematic test of the hypotheses connecting social mobility and preferences for redistribution has yet been done to date. We use the diagonal reference model to estimate the effect of origin and destination classes on preferences for redistribution in a large sample of European countries using data from the European Social Survey. Our findings are consistent with the logic of acculturation in the sense that newcomers tend to adapt their views to those of the destination class at early stages and that upward and downward mobility do not have distinctive effects on the formation of political preferences. However, even though social origins seem to have a limited impact on preferences for redistribution, the evidence does not support the hypothesis that mobile and non‐mobile individuals are alike. We also find that the effect of social origin on preferences varies largely across countries. The empirical evidence leads to the conclusion that the effect of social origin on preferences for redistribution increases in contexts of strong familism.     

Internal Migration in Spain: Dealing with Multilateral Resistance and Nonlinearites

This article investigates the determinants of internal mobility of both foreigners and natives across Spanish provinces over the decade 2004‐14. Building on an extended gravity model, our econometric strategy controls for multilateral resistance to migration by including different fixed effects structures. Additionally, the article allows for some nonlinearities in the key economic determinants of migration, wages and unemployment. The main finding is that the impact of economic factors on internal migration is higher for foreigners than for natives; furthermore, the effect of these factors on internal migration is clearly nonlinear for the group of natives, while this only happens for foreigners when dyadic fixed effects of origin‐destination are considered. Finally, the article shows that the nature of the amenities with the greatest impact on internal movements differs between the two groups: foreigners look for social services and cultural amenities, whereas natives are more attracted by good climate conditions.     

Stressful Life Events and Physical and Psychological Health: Mediating Effects of Differentiation of Self in a Spanish Sample

The pathways between differentiation of self and health remain only partly elucidated. This cross‐cultural study sought to test Bowen's hypothesis about the associations between differentiation, stressful life events, and physical and psychological health, in a sample of 466 Spanish adults. Results show that people with higher levels of differentiation were less prone to physical ailments (e.g., heart disease, cancer, or blood disorders) and psychological symptoms (e.g., depression or anxiety). Further, differentiation mediated the association between stress (i.e., perceived negativity of stress in the past year and number of stressful events across the lifetime) and physical and psychological health. The current research provides cross‐cultural empirical evidence for the links between differentiation and mind and body health in a Mediterranean culture.     

Community care for adults with severe mental disorders in rural China: A case study

In China, family care is the dominant form of care for people with mental disorders. Since 2004, the government has been developing a community‐care model that places more responsibility on community organisations and the local governments at the provincial, municipal and county levels for the provision of formal care. As a large number of people with severe mental disorders live in rural China, this case study was conducted in a rural county in order to examine the development of community care. It was found that, although family care remains dominant, families’ need for formal care is increasing. Community services have improved, but their development is constrained by several contextual and micro factors. In this study, it is argued that the community‐care model introduces a process of reconfiguration of the relative responsibility for care among the family, social organisations and the government, but progress depends on further administrative and fiscal reforms.     

Economic Stress, Quality of Life, and Mortality for the Oldest-Old in China

China??s oldest old population is estimated to quadruple by 2050. Yet, poverty rate for the oldest old has been the highest among all age groups in China. This paper investigates the relationship between economic stress, quality of life, and mortality among the oldest-old in China. Both objective economic hardships and perceived economic strain are examined. We base our investigation on data drawn from the Chinese Longitudinal Healthy Longevity Survey conducted between 2000 and 2005. Our sample includes 10,972 men and women between the ages of 80 and 105 in 2000. The data show that about 16% of these oldest-old lived under economic stress in 2000. The risk factors that make one vulnerable to economic stress include age, being male, being widowed or never married, being a minority member, having no education, having no living children, and not having children as main source of income, and having no pension. Economic stress is negatively associated with indicators of quality of life, such as the quality of medical care and mental well-being. The poor quality of life contributes to the higher mortality rate for the oldest old who are under economic stress. Results also show that perceived economic strain increases the risk of mortality by 42% in rural areas, even after controlling for basic demographic characteristics, life style factors, and major health events.?For the rural oldest-old, having children as a main source of income and having access to pension alleviates the negative impact of economic hardship on mortality hazard by 23 and 66% respectively. However, in urban areas, economic stress has no direct impact on the hazard of mortality.     

Perception of Earthquake Risk in Taiwan: Effects of Gender and Past Earthquake Experience

This study explored how individuals in Taiwan perceive the risk of earthquake and the relationship of past earthquake experience and gender to risk perception. Participants (n= 1,405), including earthquake survivors and those in the general population without prior direct earthquake exposure, were selected and interviewed through a computer‐assisted telephone interviewing procedure using a random sampling and stratification method covering all 24 regions of Taiwan. A factor analysis of the interview data yielded a two‐factor structure of risk perception in regard to earthquake. The first factor, “personal impact,” encompassed perception of threat and fear related to earthquakes. The second factor, “controllability,” encompassed a sense of efficacy of self‐protection in regard to earthquakes. The findings indicated prior earthquake survivors and females reported higher scores on the personal impact factor than males and those with no prior direct earthquake experience, although there were no group differences on the controllability factor. The findings support that risk perception has multiple components, and suggest that past experience (survivor status) and gender (female) affect the perception of risk. Exploration of potential contributions of other demographic factors such as age, education, and marital status to personal impact, especially for females and survivors, is discussed. Future research on and intervention program with regard to risk perception are suggested accordingly.     

Can Carbon Nanomaterials Improve CZTS Photovoltaic Devices? Evaluation of Performance and Impacts Using Integrated Life‐Cycle Assessment and Decision Analysis

In emergent photovoltaics, nanoscale materials hold promise for optimizing device characteristics; however, the related impacts remain uncertain, resulting in challenges to decisions on strategic investment in technology innovation. We integrate multi‐criteria decision analysis (MCDA) and life‐cycle assessment (LCA) results (LCA‐MCDA) as a method of incorporating values of a hypothetical federal acquisition manager into the assessment of risks and benefits of emerging photovoltaic materials. Specifically, we compare adoption of copper zinc tin sulfide (CZTS) devices with molybdenum back contacts to alternative devices employing graphite or graphene instead of molybdenum. LCA impact results are interpreted alongside benefits of substitution including cost reductions and performance improvements through application of multi‐attribute utility theory. To assess the role of uncertainty we apply Monte Carlo simulation and sensitivity analysis. We find that graphene or graphite back contacts outperform molybdenum under most scenarios and assumptions. The use of decision analysis clarifies potential advantages of adopting graphite as a back contact while emphasizing the importance of mitigating conventional impacts of graphene production processes if graphene is used in emerging CZTS devices. Our research further demonstrates that a combination of LCA and MCDA increases the usability of LCA in assessing product sustainability. In particular, this approach identifies the most influential assumptions and data gaps in the analysis and the areas in which either engineering controls or further data collection may be necessary.