Articles reporting research on Latin American social movements are only rarely transparent

ABSTRACT

Social movement scholars often want their research to make a difference beyond the academy. Readers will either read reports directly or they will read reviews that aggregate findings across a number of reports. In either case, readers must find reports to be credible before they will take their findings seriously. While it is not possible to predict the indicators of credibility used by individual, direct readers, formal systems of review do explicate indicators that determine whether a report will be recognized as credible for review. One such indicator, also relevant to pre-publication peer review, is methodological transparency: the extent to which readers are able to detect how research was done and why that made sense. This paper tests published primary research articles on and for social movements in Latin America for compliance with a generous interpretation of methodological transparency. We find that, for the most part, articles are not methodologically transparent. If transparency matters to social movement scholars, the research community may wish to formalize discussions of what aspects of research should be reported and how those reports should be structured.     

A hierarchical Bayesian model for predicting the functional consequences of amino-acid polymorphisms

Summary.  Genetic polymorphisms in deoxyribonucleic acid coding regions may have a phenotypic effect on the carrier, e.g. by influencing susceptibility to disease. Detection of deleterious mutations via association studies is hampered by the large number of candidate sites; therefore methods are needed to narrow down the search to the most promising sites. For this, a possible approach is to use structural and sequence-based information of the encoded protein to predict whether a mutation at a particular site is likely to disrupt the functionality of the protein itself. We propose a hierarchical Bayesian multivariate adaptive regression spline (BMARS) model for supervised learning in this context and assess its predictive performance by using data from mutagenesis experiments on lac repressor and lysozyme proteins. In these experiments, about 12 amino-acid substitutions were performed at each native amino-acid position and the effect on protein functionality was assessed. The training data thus consist of repeated observations at each position, which the hierarchical framework is needed to account for. The model is trained on the lac repressor data and tested on the lysozyme mutations and vice versa. In particular, we show that the hierarchical BMARS model, by allowing for the clustered nature of the data, yields lower out-of-sample misclassification rates compared with both a BMARS and a frequen-tist MARS model, a support vector machine classifier and an optimally pruned classification tree.     

Habitus: beyond sociology

This paper presents a contribution of a set of interrelated innovative thinking to revitalize the sociological understanding of the notion of the habitus. It discusses contributions by sociologists exploring the sources of Bourdieu's inspiration from psychology and psychoanalysis to the development of the concept, and brings in new thinking inspired by authors and frameworks that branch out of sociology to bring into sociology fresher thinking. Three areas of concern about habitus are focused on: firstly, the objectivism and subjectivism dichotomy; secondly, the plasticity or rigidity of the concept; and thirdly, the implications of intangibles attached to the notion. The paper introduces a Special Section including five articles on theoretical and empirical explorations bringing exciting perspectives to creative and critical sociology.     

Log-Weibull extended regression model: Estimation,sensitivity and residual analysis

The failure rate function commonly has a bathtub shape in practice. In this paper we discuss a regression model considering new Weibull extended distribution developed by Xie et al. (2002) that can be used to model this type of failure rate function. Assuming censored data, we discuss parameter estimation: maximum likelihood method and a Bayesian approach where Gibbs algorithms along with Metropolis steps are used to obtain the posterior summaries of interest. We derive the appropriate matrices for assessing the local influence on the parameter estimates under different perturbation schemes, and we also present some ways to perform global influence. Also, some discussions on case deletion influence diagnostics are developed for the joint posterior distribution based on the Kullback–Leibler divergence. Besides, for different parameter settings, sample sizes and censoring percentages, are performed various simulations and display and compare the empirical distribution of the Martingale-type residual with the standard normal distribution. These studies suggest that the residual analysis usually performed in normal linear regression models can be straightforwardly extended to the martingale-type residual in log-Weibull extended models with censored data. Finally, we analyze a real data set under a log-Weibull extended regression model. We perform diagnostic analysis and model check based on the martingale-type residual to select an appropriate model.     

Genetic algorithms for the analysis of Bayesian hierarchical partition models

Hierarchical partition models (see Malec and Sedransk, 1992, Consonni and Veronese, 1995) aim at finding an optimal grouping (partition) of a set of experiments regarding a target variable. In this class of models the partition is regarded as an unknown parameter, and one of the main goals is computing the posterior distribution over the class of the possible partitions. This problem has been addressed in Sampietro and Veronese (1998), where a Metropolis-Hastings algorithm is applied. In this paper the performance of an alternative procedure, based on the logic of genetic algorithms, is evaluated. The results of the two approaches are compared, even if a conjoint use of them is to be advised.