Expanded renal transplantation: a competing risk model approach

Multi-state models (MSMs) are useful to analyze survival data when, besides the event of main interest, one or more intermediate states of the individual are identified. These models take the several existing states and the possible transitions among them into account. At the same time, covariate effects on each transition intensity may be investigated separately and, therefore, MSMs are more flexible than the standard Cox proportional hazards model. In this work, we use MSMs to investigate the impact of the quality of a transplanted kidney for a group of patients at the Hospital Universitario Central de Asturias. Specifically, we use an illness-death model to study the evolution of patients with kidney disease who received a renal transplant after a dialysis period. The intermediate state is defined as the failure of the received organ, while the terminating state is the death of the patient. In order to increase the potential number of organs available for transplant, the standards of quality for the transplanted kidneys were relaxed (the new criteria are labeled expanded criteria), and these ‘expanded kidneys’ were transplanted in appropriate candidates (older patients, with higher prevalence of diabetes mellitus). Results suggest that the expanded kidneys have a minor effect on survival, while both the kidney mortality and the risk of death increase with the patient's age and the serum creatinine and serum hemoglobin levels.     

Immigrants and refugees: two sides of the same problem. A linguistic analysis through newspapers and social network in Spain 2006 and 2015

ABSTRACT

The phenomenon of immigration has been studied from diverse perspectives. It is important to note that immigration is common during times of crisis. The reason for the avalanche of immigrants to the Canary Islands (Spain) is because it is the gateway to Europe, and therefore, immigrants wanted to enter from this point. This research is based on the need to linguistically determine the treatment of the phenomenon of immigration in the Spanish press. This analysis is relevant given the arrival of thousands of foreign citizens to the coast of the Canary Islands, first in 2006 and almost a decade later, in 2015 to the south of Europe in another great population movement. This research attempts to study four Spanish newspapers, two from the Canary Islands (El Día and Canarias 7) and two Spanish mainland national newspapers (El País and ABC), the online version of the newspapers and their websites were analyzed beside one of the most important social networks, Twitter. The role of incorporating social networks to immigration discourse is also analyzed. To support the data analysis of this research, the Iramuteq software was used.     

On the asymptotic distribution of Cook's distance in logistic regression models

It sometimes occurs that one or more components of the data exert a disproportionate influence on the model estimation. We need a reliable tool for identifying such troublesome cases in order to decide either eliminate from the sample, when the data collect was badly realized, or otherwise take care on the use of the model because the results could be affected by such components. Since a measure for detecting influential cases in linear regression setting was proposed by Cook [Detection of influential observations in linear regression, Technometrics 19 (1977), pp. 15–18.], apart from the same measure for other models, several new measures have been suggested as single-case diagnostics. For most of them some cutoff values have been recommended (see [D.A. Belsley, E. Kuh, and R.E. Welsch, Regression Diagnostics: Identifying Influential Data and Sources of Collinearity, 2nd ed., John Wiley & Sons, New York, Chichester, Brisban, (2004).], for instance), however the lack of a quantile type cutoff for Cook's statistics has induced the analyst to deal only with index plots as worthy diagnostic tools. Focussed on logistic regression, the aim of this paper is to provide the asymptotic distribution of Cook's distance in order to look for a meaningful cutoff point for detecting influential and leverage observations.     

A Study of the Role Played by Manufacturing Strategic Objectives and Capabilities in Understanding the Relationship between Porter's Generic Strategies and Business Performance

An appropriate alignment between business strategy, manufacturing strategic objectives and manufacturing capabilities reportedly influences business performance positively. However, few papers empirically analyse this proposition for the case of Porter's generic strategies of cost leadership and differentiation, and none jointly considers all four elements. This paper integrates strategies, capabilities and performance in a single model and proposes that both manufacturing competitive priorities and capabilities, articulated in terms of cost and flexibility, are essential for explaining the link between generic business strategies and business commercial and financial performance. Within this analytic framework, we test whether companies that emphasize one business strategy rather than another achieve a better alignment and superior performance. The analyses conducted with a sample of 148 Spanish manufacturers provide general support for these propositions and contribute to a deeper understanding of the role played by functional strategies in understanding the outcomes of business strategy.     

Modeling healthcare costs in simultaneous presence of asymmetry,heteroscedasticity and correlation

Highly skewed outcome distributions observed across clusters are common in medical research. The aim of this paper is to understand how regression models widely used for accommodating asymmetry fit clustered data under heteroscedasticity. In a simulation study, we provide evidence on the performance of the Gamma Generalized Linear Mixed Model (GLMM) and log-Linear Mixed-Effect (LME) model under a variety of data-generating mechanisms. Two case studies from health expenditures literature, the cost of strategies after myocardial infarction randomized clinical trial on the cost of strategies after myocardial infarction and the European Pressure Ulcer Advisory Panel hospital prevalence survey of pressure ulcers, are analyzed and discussed. According to simulation results, the log-LME model for a Gamma response can lead to estimations that are biased by as much as 10% of the true value, depending on the error variance. In the Gamma GLMM, the bias never exceeds 1%, regardless of the extent of heteroscedasticity, and the confidence intervals perform as nominally stated under most conditions. The Gamma GLMM with a log link seems to be more robust to both Gamma and log-normal generating mechanisms than the log-LME model.     

Does Parental Participation in Schools Empower or Strain Civil Society? The Case of Community‐managed Schools in Central America

Among the various educational models in Latin America that seek to increase parental participation in schooling, perhaps the most far‐reaching is the experiment with self‐managed schools. These are publicly funded schools administered by parents. Broad public powers, such as the capacity to decide the budget and make staffing decisions, are given to parents, many of whom have had very limited prior administrative experience. How does this policy innovation impact on civil society? Does parental participation in school administration empower participating citizens or strain civil society? There are various ways of answering these questions. This article looks at some possible ways to conceptualize and assess the relationship between parental participation in self‐managed schools and civil society. The article draws from the experience of El Salvador, Guatemala, Honduras and Nicaragua, where these reforms have advanced significantly since the 1990s.     

Spiritual Needs and Quality of Life in Estonia

This paper reports on three field studies using the WHOQOL-100 and WHOQOL-BREF instruments that utilized three different samples (N = 1,801) to get a better understanding of how important the person’s spiritual needs are for quality of life. The most striking negative difference between the Estonian and World Health Organization samples was in the WHOQOL-100 spirituality domain. We found that the quality of life index significantly correlated with the WHOQOL-100 spirituality score. Also, spirituality was related to all quality of life domains (physical health, psychological well-being, level of independence, social relationships and environment). Regarding psychological well-being, spirituality correlated with self-esteem, positive feelings, and thinking, learning, memory, and concentration, on the other. Our findings suggest that spirituality occupies an important place in the person’s perception of their quality of life in a changing socio–economic environment as the one in Estonia.     

Quality certification, institutions and innovation in local agro-food systems: Protected designations of origin of olive oil in Spain

This article examines the interrelations between establishment of territorial quality certification systems (Protected Designations of Origin or PDOs), diffusion of innovations through local agro-food chains, and the role of the institutions overseeing geographical designations. Empirical analysis is applied to olive oil PDOs in Spain and entails a detailed case study of the “Sierra Mágina” PDO in Andalusia. Making use of the neoinstitutional concept of ‘organised proximity’—and focussing specifically on the problematic of organizational quality—the article assesses characteristics that support the competitive positions of local certified-product production systems. In particular, the authors find that collective organisation and coordination between PDO agents who are locally responsible for quality assurance and protection can enhance local competitiveness. Three hypotheses are confirmed. First, PDO labels can, through the action of PDO regulators, become quality assurance systems for distributors. Second, PDO Regulatory Boards can enhance and coordinate local inter-professional activities, particularly with respect to the diffusion of quality-enhancing innovations and knowledge. Third, the study indicates that local certified-product systems are starting to incorporate quality attributes linked to the environment and sustainable development, although much remains to be accomplished in this regard.