A new semiparametric Weibull cure rate model: fitting different behaviors within GAMLSS

ABSTRACT

We propose a new semiparametric Weibull cure rate model for fitting nonlinear effects of explanatory variables on the mean, scale and cure rate parameters. The regression model is based on the generalized additive models for location, scale and shape, for which any or all distribution parameters can be modeled as parametric linear and/or nonparametric smooth functions of explanatory variables. We present methods to select additive terms, model estimation and validation, where all computational codes are presented in a simple way such that any R user can fit the new model. Biases of the parameter estimates caused by models specified erroneously are investigated through Monte Carlo simulations. We illustrate the usefulness of the new model by means of two applications to real data. We provide computational codes to fit the new regression model in the R software.     

Older People’s Motivations to Engage in Political Organizations: Evidence from a Catalan Study

This study explored the motivations of Catalan older people to engage in political organizations. The sample consisted of 192 people aged 65 and over who were active members of three types of political organizations: neighborhood associations, political parties/trade unions, and single-issue organizations. Their answers to an open-ended question were content analyzed, and a series of Chi-square tests were run to assess the association of the resulting categories with the type of organization in which participants were active. The results show that the motives for engaging in political organizations were mainly focused on introducing changes in the community, although the scope of the changes desired tended to vary. While some participants expressed idealistic motivations, others stated that they become involved in order to stand up for a cause in which they believed. One in six participants was motivated by self-interest, either related to personal growth or to self-protective needs. Motives for participating were related to the type of organization in which participants were active, suggesting that organizations should consider the influence of their own particular context and characteristics in developing recruitment and retention strategies.     

Public-Private Partnership Contractual Design: A Computational Model of the Moral Hazard with Lotteries

Public-Private Partnership (PPP) is a new model of public management which consists of the contractual relationship between public and private entities. In particular, PPPs enable risk share between public and private sectors making the asymmetric information problem in a contractual arrangement more evident. The aim of this paper was to study a moral hazard problem applied to PPP contracts. To achieve this objective, a PPP computational contractual model including the moral hazard with lotteries was developed to assess how contractual changes could affect the optimum behavior of arrangement members. Simulations indicate that projects with higher economic value should attract more qualified firms, which may be why the companies expend more effort. To deal with possible contractual contingencies and try to minimize the moral hazard problem, the government could draw up more flexible contracts in order to include possible necessary changes and punish unwanted or improper consortium behavior.     

Managing ergonomics in the development of rotation between workstations in the automotive industry. A balance between health and traceability of tasks

Abstract When the subject rotation between workstations (job rotation) is inside the organizations it's seemed that technically there are lots of restrictions to the development of an adequate system of rotation. We went from the need for an advanced ergonomic study and even possible restrictions of versatility and training of employees. The implementation of the ideal system of rotation passes through stages of development and research ergonomic study of the level of employee versatility, awareness and discussion with employees, implementation of the proposed system, feedback and audits for maintenance of the ideal sequence and time of rotation. For the success of the project there is a need for multidisciplinary involvement in the areas of manufacturing engineering, industrial engineering, human resources, medical services and manufacturing. Rotation between the tasks may mean that a worker should conduct two or more different activities in different parts of the day (ie. change between activity A and activity B "between 1 hours and 2 hours interval). An important consideration is to ensure that different activities do not present the same ergonomic risk for the same body part. The tracing of the execution of the activity is an important factor for production processes. Thus it is possible to conduct appropriate levels of training for employees and ensure safe and sustainable processes in terms of workers' health, productivity and quality.     

Authorship Trends in The Analysis of Verbal Behavior: 1982–2016

The Analysis of Verbal Behavior - The Analysis of Verbal Behavior (TAVB) is the only journal focused on theoretical and empirical research in verbal behavior. An assessment of authorship trends can...     

Towards sustainability by aligning operational programmes and sustainable performance measures

Abstract

In the last decades, sustainable concerns have increasingly gained importance to organizational survival, and Lean/Six Sigma approaches are becoming more and more outstanding in order to improve sustainability performance. This article aims to evaluate the degree of importance of sustainable performance measures of Brazilian organizations and to propose guidelines to achieve sustainability by aligning these measures with operational improvement programmes. Multiple data collection methods were applied as theoretical literature review, questionnaire survey and semi-structured interviews with industry professionals and academic researchers. The findings show that it is the corporate responsibility to focus their efforts on both operational improvement programmes and sustainable initiatives in order to achieve better environmental protection, corporate reputation, quality management, cost performance and suppliers relations, as they are considered to be more important on organizational sustainability.     

Parametric Bayesian inference for Y-linked two-sex branching models

A Y-linked two-sex branching process with blind choice is a suitable model for analyzing the evolution of the number of carriers of two alleles of a Y-linked gene in a two-sex monogamous population where each female chooses her partner from among the male population without caring about his type (i.e., the allele he carries). This work focuses on the development of Bayesian inference for this model, considering a parametric framework with the reproduction laws belonging to the power series family of distributions. A sample is considered given by the observation of the total number of females and males (regardless of their types) up to some generation as well as the number of each type of male in the last generation. Using a simulation method based on the Gibbs sampler, we approximate the posterior distributions of the main parameters of this model. The accuracy of the procedure based on this sample is illustrated by way of a simulated example.     

Tempus Edax Rerum: Measuring the incumbency advantage in the U.S. House of Representatives

Many studies provide valuable insight on the electoral incumbency advantage; however, little work provides insight or an organized theory for how such an advantage develops for career politicians. We develop such a theory, arguing that to understand the incumbency advantage at the time of an electoral victory, it is necessary to consider the length of each specific congressional career. We find that the total share of the incumbent vote received has a curvilinear relationship with the number of years any House Member spends in office. Our findings also result in a better understanding of the incumbency advantage in the U.S. then previous conceptualizations and allows for comparisons of the incumbency advantage across the two Chambers of Congress, other elective offices, and even across democratic political systems.     

Coefficients of determinations for variable selection in the msae regression

Our objective is to modify a robust coefficient of determination for the minimum sum of absolute errors MSAE regression proposed by McKean and Sievers (1987) so that it satisfies all the desirable properties. We also propose an adjusted coefficient of determination that is appropriate for comparing several models with different number of variables. Further, it has the property that if it decreases with the addition of predictor variables to the model, then the contribution of these variables is statistically non-significant. We illustrate the results with an example.