Nuisance parameter free properties of correlation integral based statistics

This paper presents conditions under which statistics based on the correlation integral are invariant to the use of estimated residuals from dynamic models. The methods are applied to the so-called BDS test for nonlinearity, under a variety of data-generating processes.     

Support Vector Clustering for Customer Segmentation on Mobile TV Service

This article presents a proposal for customer segmentation through Support Vector Clustering, a technique that has been gaining attention in the academic literature due to the good results usually obtained. An application of this method to a sample from consumers in Brazil about mobile TV service is performed; we compare this approach with the classical hierarchical methods of cluster analysis. It is concluded that this methodology is effective in reducing the heterogeneity often present in customers’ data, improving the cluster segmentation analysis for managers.     

Sample Partitioning Estimation for Ergodic Diffusions

In this article, we present a new technique to obtain estimators for parameters of ergodic processes. When a diffusion is ergodic its transition density converges to the invariant density Durett (1996 Durett, R. (1996). Stochastic Calculus. A Practical Introduction. New York: CRC Press. [Google Scholar]). This convergence enabled us to introduce a sample partitioning technique that gives, in each subsample, observations that can be treated as independent and identically distributed. Within this framework, is possible the construction of estimators like maximum likelihood estimators or others.     

Cognitive Factors and Male Genital Pain: A Preliminary Study

Objectives: This study aimed to evaluate how pain catastrophizing and sexually related thoughts help explain pain intensity in men with genital pain. Methods: Fifty men with genital pain completed an online survey. Results: Sexually related thoughts explained an additional 11.5% of variance of pain intensity, above and beyond the influence of pain catastrophizing and medical conditions. Conclusions: Overall, findings showed that cognitions during sexual activity also contribute to explain pain intensity in men with genital pain. Besides the severity of organic factors and pain catastrophizing, sexually-related thoughts should also be included in clinical evaluation and treatment of male genital pain.     

Estimating Parliamentary composition through electoral polls

Summary.  All electoral systems have an electoral formula that converts proportions of votes into Parliamentary seats. Pre-electoral polls usually focus on estimating proportions of votes and then apply the electoral formula to give a forecast of Parliamentary composition. We describe the problems that arise from this approach: there will typically be a bias in the forecast. We study the origin of the bias and some methods for evaluating and reducing it. We propose a bootstrap algorithm for computing confidence intervals for the allocation of seats. We show, by Monte Carlo simulation, the performance of the proposed methods using data from Spanish elections in previous years. We also propose graphical methods for visualizing how electoral formulae and Parliamentary forecasts work (or fail).     

Shaping ways of managing diversity in Portuguese schools,from the student's perspective

This article examines the results of an empirical research project that analysed the political socialisation processes of the students at three Portuguese public secondary schools in the Lisbon Metropolitan Area in 2011. Against the background of the implementation of an ‘education for citizenship’ programme in the official Portuguese school curriculum (2001), the project basically sought to know what attitudes the students mobilised in the face of a hypothetical situation involving the presence of ciganos (gypsies) in a school context. In this respect, and based on a pragmatic and comprehensive perspective, we attempted to test the concept of multiculturality and how it is seen and experienced by the students at these schools. Our aim is to answer the question: In a school context, how do students think the coexistence of gypsies and non-gypsies should be managed? In seeking to answer this question, the methodology that seemed to us most appropriate to this study's objectives is founded on the mobilisation of a scenario-based questionnaire, and to this purpose we surveyed 700 secondary students in a classroom environment. We were able to identify and characterise four possible coexistence formats within the overall framework of a synoptic vision of the available ways of managing a multicultural experience: separation; socialisation; universalism; and co-operation.     

Prevalence of Sexual Problems in Portugal: Results of a Population-Based Study Using a Stratified Sample of Men Aged 18 to 70 Years

Despite the use of different methodologies, target populations, and clinical definitions of sexual problems, recent epidemiological studies have shown that the occurrence of sexual difficulties is a very common experience among men from the general population regardless of their age. The objective of this study was to present epidemiological data on the prevalence of sexual difficulties in a community sample of 650 sexually active Portuguese men, stratified by age, marital status, and educational level. Participants completed a self-reported questionnaire assessing sexual function in the previous four weeks (International Index of Erectile Function). Results showed that sexual difficulties were relatively common among this sample. Rapid ejaculation was the most frequently reported sexual difficulty (23.2%), followed by erectile difficulties (10.2%), orgasm problems (8.2%), and low desire (2.9%) in the previous four weeks. With the exception of rapid ejaculation, all categories showed age-specific prevalence rates, with sexual difficulties increasing gradually in men above age 45. Age was a significant predictor of all sexual difficulties except rapid ejaculation, and lower educational levels were related to orgasm difficulties. Findings are consistent with the majority of epidemiological studies indicating a high prevalence of sexual difficulties among men in the general population and highlight the importance and the need to implement sexual health promotion programs in the target population.     

Mimicry and the Judgment of Emotional Facial Expressions

Lipps (1907) presented a model of empathy which had an important influence on later formulations. According to Lipps, individuals tend to mimic an interaction partner's behavior, and this nonverbal mimicry induces—via a feedback process—the corresponding affective state in the observer. The resulting shared affect is believed to foster the understanding of the observed person's self. The present study tested this model in the context of judgments of emotional facial expressions. The results confirm that individuals mimic emotional facial expressions, and that the decoding of facial expressions is accompanied by shared affect. However, no evidence that emotion recognition accuracy or shared affect are mediated by mimicry was found. Yet, voluntary mimicry was found to have some limited influence on observer' s assessment of the observed person's personality. The implications of these results with regard to Lipps' original hypothesis are discussed.