Global and local tests to assess stationarity of Markov transition models

We present global and local likelihood-based tests to evaluate stationarity in transition models. Three motivational studies are considered. A simulation study was carried out to assess the performance of the proposed tests. The results showed that they present good performance with the control of the type-I error, especially for ordinal responses, and control of the type-II error, especially for the nominal case. Asymptotically they are close to the classical test performance. They can be executed in a single framework without the need to estimate the transition probabilities, incorporating both categorical and continuous covariates, and used to identify sources of non-stationarity.     

Financial management in long-term low-income households: comparing perspectives of professionals and families in Portugal

Long-term low-income households face economic hardship, together with a lack of opportunities, which restrict their social participation. There is a widely held belief among professionals that these households poorly manage their finances. This exploratory study aims to gain a deeper understanding of these households' difficulties and strategies of family financial management in Portugal, taking into account the perspectives of both members of the households and professionals. Comparing viewpoints is relevant in order to identify how they might be informing interactions and interventions. A qualitative approach based on semi-structured interviews was used; the sample comprised 10 household members and 10 professionals. The main findings suggest that professionals believe these households demonstrate insufficient management strategies, while household members report struggling to manage insufficient resources. These distinctive views seem to facilitate interaction patterns characterized by mutual distrust, which should be taken into consideration when designing interventions, particularly concerning financial management.     

Oral,systemic and socioeconomic factors associated with preterm birth

Background

The rates of preterm births have been increasing worldwide. Complications related to preterm births are associated with increased costs of care, and have a direct impact on the health system of the countries. Therefore, it is important to address factors associated with preterm birth in order to provide prevention strategies.

Sociosexuality,Commitment, Sexual Infidelity,and Perceptions of Infidelity: Data From the Second Love Web Site

This study explored the association between sociosexuality (behavior, attitudes, and desire) and commitment to understand sexual infidelity in current relationships. We also explored how these variables were associated with attitudes toward infidelity. Participants were romantically involved heterosexuals (N = 252; 51 women, 201 men; M_age = 41.13, SD = 9.82) registered on a dating Web site directed at romantically involved individuals. Results showed that sociosexuality, alongside commitment, was associated with sexual infidelity. Individuals who had (versus had not) previously engaged in infidelity reported more unrestricted sociosexuality, while reporting less commitment. For individuals reporting prior sexual infidelity, unrestricted sociosexual desire and lesser commitment were associated with more permissive perceptions of infidelity. For individuals reporting no prior sexual infidelity, greater commitment was always associated with more strict perceptions of infidelity. No gender differences emerged in the analyses. Also, no differences were found according to individual motivations (i.e., looking to know other people versus seeking casual sex) or relational motivations (i.e., individual registration versus registration as a couple) underlying individuals’ registration on the Web site. These results are an important addition to the literature on infidelity by analyzing a specific sample motivated to engage in infidelity. Implications for future research are discussed.     

Frailty models power variance function with cure fraction and latent risk factors negative binomial

In this article, we propose a flexible cure rate model, which is an extension of Cancho et al. (2011 Cancho, V.G., Rodrigues, J., de Castro, M. (2011). A flexible model for survival data with a cure rate: A Bayesian approach. J. Appl. Stat. 38:57–70.[Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]) model, by incorporating a power variance function (PVF) frailty term in latent risk. The model is more flexible in terms of dispersion and it also quantifies the unobservable heterogeneity. The parameter estimation is reached by maximum likelihood estimation procedure and Monte Carlo simulation studies are considered to evaluate the proposed model performance. The practical relevance of the model is illustrated in a real data set of preventing cancer recurrence.     

Destructive weighted Poisson cure rate models

In this paper, we develop a flexible cure rate survival model by assuming the number of competing causes of the event of interest to follow a compound weighted Poisson distribution. This model is more flexible in terms of dispersion than the promotion time cure model. Moreover, it gives an interesting and realistic interpretation of the biological mechanism of the occurrence of event of interest as it includes a destructive process of the initial risk factors in a competitive scenario. In other words, what is recorded is only from the undamaged portion of the original number of risk factors.     

Development and Validation of a Self-Reported Measure of Job Performance

Social Indicators Research - The current turbulent context in which we live in requires, more and more, that organisations focus on improving the workers’ performance. Individual performance...     

Defective models induced by gamma frailty term for survival data with cured fraction

In this paper, we propose a defective model induced by a frailty term for modeling the proportion of cured. Unlike most of the cure rate models, defective models have advantage of modeling the cure rate without adding any extra parameter in model. The introduction of an unobserved heterogeneity among individuals has bring advantages for the estimated model. The influence of unobserved covariates is incorporated using a proportional hazard model. The frailty term assumed to follow a gamma distribution is introduced on the hazard rate to control the unobservable heterogeneity of the patients. We assume that the baseline distribution follows a Gompertz and inverse Gaussian defective distributions. Thus we propose and discuss two defective distributions: the defective gamma-Gompertz and gamma-inverse Gaussian regression models. Simulation studies are performed to verify the asymptotic properties of the maximum likelihood estimator. Lastly, in order to illustrate the proposed model, we present three applications in real data sets, in which one of them we are using for the first time, related to a study about breast cancer in the A.C.Camargo Cancer Center, São Paulo, Brazil.     

The methodological involvement of the emotional design and cognitive ergonomics as a tool in the development of children products

To demonstrate the relationship between design and emotional development for kids, this article offers an initial approach about the definition and historical aspects of emotion in product development, citing the main authors of this issue. Based the field research conducted with children from 2 to 6 years of age, was also describes the basic ideas of Piaget in the child psychology and pre-operational stage (age group studied) and the significance of children's toys from the perspective of Vigostsky. Using this theoretical framework and results of field research, we can infer some emotional design as advocated by the producers of positive affect on humans and its relationship with the child's development and choices of their toys.     

A computerized system to monitor resilience indicators in organizations

The concepts developed by resilience engineering allow the understanding and monitoring the functioning of organizations and, particularly, to map the role of human activities, in success or in failure, enabling a better comprehension about how people make decisions in unexpected situations. The capture of information about human activities in the various organization levels gives managers a deeper real-time understanding of what is influencing the people performance, providing awareness of the factors that influence positively or negatively the organizational goals initially projected. The monitoring is important because the correct functioning of complex systems depends on the knowledge that people have to perform their activities and how the system environment provides tools that actually support the human performance. Therefore, organizations should look forward through precursors in operating signals to identify possible problems or solutions in the structure of tasks and activities, safety, quality, schedule, rework, and maintenance. We apply the concepts of resilience engineering to understand the organization by the analysis of cognitive tasks and activities. The aim is the development of a computerized system to monitor human activities to produce indicators to access system resilience. The validation of the approach was made in a real organization and the results show the successful applicability of the system. Based on findings obtained after the experiment of the system in a real organization, and managers and workers opinions, it was possible to show that the use of system provided an anticipated (real-time) perception about how activities are effectively being performed, allowing managers and workers to make decisions more consistent with daily problems, and also to anticipate solutions to cope with unexpected situations.