Structural changes in multivariate regression models

This study generalizes the work of chin choy and Broemeling (1980) who investigated the change in the regression parameters of univariate linear models.

The marginal posterior distributions of the change point, the regression matrices,and the precision matrix are found with the use of a proper multivariate normal-Wishart distribution for the parameters of the model.

A numerical study is undertaken in order to gain some insight into the effect that changes in sample size and certain parameter values have on these marginal posterior distributions.     

Parameter changes in a regression model with autocorrelated errors

This study is a Bayesian analysis of a regression model with autocorrelated errors which exhibits one change in the regression parameters and where the autocorrelation parameter is unknown

Using a normal-gamma prior for all the parameters except the shift point which has a uniform distribution, the marginal posterior distribution of the regression parameters, the shift point and the precision of the errors is found. It is important to know where the shift occurred thus the main emphasis is with the posterior distribution of the shift point

A numerical study assesses the effect of the values of the shift point and the magnitude of the shift on the posterior distribution of the shift point. The posterior distribution of the shift point is more sensitive to change, which occurs in the middle of the observations than to one which occurs at an extreme of the data.     

The Sound of Silence. Lesbian,Gay, Bisexual and Transgender Discrimination in ‘Inclusive Organizations’

Most studies on diversity and discrimination in the workplace have focused on ‘visible’ minorities such as gender or race, often neglecting the experiences of invisible minorities such as lesbian, gay, bisexual and transgender (LGBT) workers. In this paper we explore the practices of inclusion/exclusion of LGBTs in the workplace in Italian social cooperatives, which are specifically founded to create employment for people who are disadvantaged in the labour market. The study examines how organizations, which have an ethos focused on inclusion and mainly employ workers from specific social minority groups, manage the inclusion of LGBT workers. We also explore the experience of LGBT workers within these organizations. The paper reports that the culture of silence existing in the five organizations studied prevents LGBT employees from constructing a work identity which encompasses their sexual identity and prevents the organizations from achieving their aim of being fully inclusive workplaces.     

Turning the Immigration Policy Paradox Upside Down? Populist Liberalism and Discursive Gaps in South America

A paradox of officially rejecting but covertly accepting irregular migrants has long been identified in the immigration policies of Western immigrant receiving states. In South America, on the other hand, a liberal discourse of universally welcoming all immigrants, irrespective of their origin and migratory status, has replaced the formally restrictive, securitized and not seldomly ethnically selective immigration rhetoric. This discursive liberalization has found partial translation into immigration laws and policies, but contrary to the universality of rights claimed in their discourses, governments reject recently increasing irregular south–south migration from Africa, Asia, and the Caribbean to varying degrees. This paper applies a mixed methodological approach of discourse and legal analysis and process tracing to explore in how far recent immigration policies in South America constitute a liberal turn, or rather a reverse immigration policy paradox of officially welcoming but covertly rejecting irregular migrants. Based on the comparative analysis of Argentina, Brazil and Ecuador, the study identifies and explains South American “populist liberalism” in the sphere of migration. We highlight important implications for migration theory, thereby opening up new avenues of research on immigration policy making outside Western liberal democracies, and particularly in predominantly migrant sending countries.     

Advancing a qualitative turn in news media trust research

The contemporary media environment represents the greatest challenge ever to journalism's legitimacy. Surveys conducted in different parts of the world highlight a decline in trust in news media. Due to the numerous changes in the news media environment, different investigative tools are required to grasp the mechanisms underlying news media trust from those adopted so far. This article provides a review of existing media trust research and argues that it is necessary to investigate news media trust (also) from a qualitative perspective because today understanding media trust is as crucial as measuring it.     

Bayesian beta nonlinear models with constrained parameters to describe ruminal degradation kinetics

The models used to describe the kinetics of ruminal degradation are usually nonlinear models where the dependent variable is the proportion of degraded food. The method of least squares is the standard approach used to estimate the unknown parameters but this method can lead to unacceptable predictions. To solve this issue, a beta nonlinear model and the Bayesian perspective is proposed in this article. The application of standard methodologies to obtain prior distributions, such as the Jeffreys prior or the reference priors, involves serious difficulties here because this model is a nonlinear non-normal regression model, and the constrained parameters appear in the log-likelihood function through the Gamma function. This paper proposes an objective method to obtain the prior distribution, which can be applied to other models with similar complexity, can be easily implemented in OpenBUGS, and solves the problem of unacceptable predictions. The model is generalized to a larger class of models. The methodology was applied to real data with three models that were compared using the Deviance Information Criterion and the root mean square prediction error. A simulation study was performed to evaluate the coverage of the credible intervals.     

The Relational Antecedents of Interpersonal Helping: ‘Quantity’, ‘Quality’ or Both?

Having a large network of colleagues means having several opportunities to help those colleagues, as well as a higher chance of receiving requests for help from them. Employees with large networks are therefore expected to help more in the workplace than those with small networks. However, large networks are also associated with cognitive costs, which may reduce the focal employee's ability to both recognize the need for help and engage in helping behaviours. For these reasons, the authors assert an inverted U‐shaped relation between the size of an ego's social network and engagement in helping behaviour. However, high‐quality relationships imply higher mutual understanding between the actors, and hence lower cognitive costs. In turn, the position (and threshold) of the curve between network size and interpersonal helping should be influenced by the quality of the relationship between the provider and the beneficiaries of help. Analysis of employee‐level, single‐firm data supports these ideas, providing preliminary evidence that quality of relationship compensates for the difficulties that may arise from having large social networks.     

Income and Beyond: Multidimensional Poverty in Six Latin American Countries

This paper studies multidimensional poverty for Argentina, Brazil, Chile, El Salvador, Mexico and Uruguay for the period 1992–2006. The approach overcomes the limitations of the two traditional methods of poverty analysis in Latin America (income-based and unmet basic needs) by combining income with five other dimensions: school attendance for children, education of the household head, sanitation, water and shelter. The results allow a fuller understanding of the evolution of poverty in the selected countries. Over the study period, El Salvador, Brazil, Mexico and Chile experienced significant reductions in multidimensional poverty. In contrast, in urban Uruguay there was a small reduction in multidimensional poverty, while in urban Argentina the estimates did not change significantly. El Salvador, Brazil and Mexico, and rural areas of Chile display significantly higher and more simultaneous deprivations than urban areas of Argentina, Chile and Uruguay. In all countries, deprivation in access to proper sanitation and education of the household head are the highest contributors to overall multidimensional poverty.     

Nonmanipulable voting schemes when participants' interests are partially decomposable

Recent papers by Barberá and Peleg and by Zhou have established that the Gibbard-Satterthwaite Theorem remains valid when individuals are restricted to reporting only reasonable preferences. We present a theorem that covers situations in which, as in Barberá-and-Peleg and Zhou, preferences may be restricted to reasonable ones, but in which, additionally, it may be known in advance that some dimensions of the social decision do not affect all the participants — i.e., in which the social decisions are partially decomposable into decisions that affect only subsets of the participants. As in the previous theorems, the conclusion of this new theorem is that nonmanipulable voting schemes must be dictatorial.An early version of this paper was delevered at the 1989 NBER-NSF Conference on Decentralization at Cal Tech; comments by the conference participants are appreciated, as are comments by James Schmitz.