Bayesian analysis of the generalized gamma distribution using non-informative priors

The Generalized gamma (GG) distribution plays an important role in statistical analysis. For this distribution, we derive non-informative priors using formal rules, such as Jeffreys prior, maximal data information prior and reference priors. We have shown that these most popular formal rules with natural ordering of parameters, lead to priors with improper posteriors. This problem is overcome by considering a prior averaging approach discussed in Berger et al. [Overall objective priors. Bayesian Analysis. 2015;10(1):189–221]. The obtained hybrid Jeffreys-reference prior is invariant under one-to-one transformations and yields a proper posterior distribution. We obtained good frequentist properties of the proposed prior using a detailed simulation study. Finally, an analysis of the maximum annual discharge of the river Rhine at Lobith is presented.     

Shaping emotional reactions to ethical behaviors: Proactive personality as a substitute for ethical leadership

Due to ethical lapses of leaders, interest in ethical leadership has grown, raising important questions about the responsibility of leaders in ensuring moral and ethical conduct. However, research on ethical leadership has failed to examine the active role that followers' attributes play in enhancing or minimizing the influence of ethical leadership in organizational outcomes. We applied the substitutes for leadership approach (Kerr & Jermier, 1978) to ethical leadership and predicted that proactive personality acts as substitute in the relationship between ethical leadership, workplace emotions and organizational citizenship behaviors (OCBs). Data from two distinct samples offered strong support for the hypotheses. Specifically, we found that ethical leadership was significantly and negatively related to negative workplace emotions when subordinate proactive personality was low, but not when it was high, with consequences for OCBs. These findings suggest that proactive personality constitutes an important moderator on the impact of low ethical leadership on workplace emotions, with consequences for OCBs.     

Augmented-limited regression models with an application to the study of the risk perceived using continuous scales

Studies of risk perceived using continuous scales of [0,100] were recently introduced in psychometrics, which can be transformed to the unit interval, but the presence of zeros or ones are commonly observed. Motivated by this, we introduce a full inferential set of tools that allows for augmented and limited data modeling. We considered parameter estimation, residual analysis, influence diagnostic and model selection for zero-and/or-one augmented beta rectangular (ZOABR) regression models and their particular nested models, which is based on a new parameterization of the beta rectangular distribution. Different from other alternatives, we performed maximum-likelihood estimation using a combination of the EM algorithm (for the continuous part) and Fisher scoring algorithm (for the discrete part). Also, we perform an additional step, by considering other link functions, besides the usual logistic link, for modeling the response mean. By considering randomized quantile residuals, (local) influence diagnostics and model selection tools, we identified that the ZOABR regression model is the best one. We also conducted extensive simulations studies, which indicate that all developed tools work properly. Finally, we discuss the use of this type of models to treat psychometric data. It is worthwhile to mention that applications of the developed methods go beyond to Psychometric data. Indeed, they can be useful when the response variable in bounded, including or not the respective limits.     

HIV seroprevalence and risk behaviors among clients attending a clinic for the homeless in Miami/Dade County,Florida, 1990–1996

In the early 1990s, HIV seroprevalence was highest at the Miami homeless clinic among 16 homeless sites participating in a nationwide sentinel survey. To examine dynamic seroprevalence patterns in Miami's homeless clients in relation to demographics and risk behaviors over six years, we analyzed data from an unlinked (blinded) serosurvey of clients attending the principal primary care clinic serving Miami's homeless. Data were from 3,797 medical encounters with homeless persons who, on their initial clinic visit within an annual survey period, received routine serologic testing and a risk behavior survey. Overall HIV seroprevalence was 15.9% and infection rates for men (16.4%) and women (14.5%) did not differ. Seroprevalence for blacks (19.9%) was significantly higher than for Hispanics (9.1%) or whites (8.3%) (p < 0.0001). Seroprevalence was 12.6% (35 times the national rate) for clients reporting heterosexual contact as their only risk. Significant increases in seroprevalence, above this heterosexual-contact-only 'baseline', were found for clients disclosing high-risk behaviors: male-to-male sex, drug injection, receiving or giving money/drugs for sex, and sexual contact with a drug injector or HIV-infected partner (p < 0.0001). Seroprevalence declined over six years from 23.2 to 7.2% (p < 0.0001). Significant downward trends were observed for men and women, blacks and Hispanics, men who have sex with men, and clients reporting heterosexual contact. The proportion of clients reporting high-risk behaviors decreased sharply (p < 0.0001). Elevated HIV seroprevalence in Miami's homeless clients was strongly associated with high-risk behaviors. Expansion of HIV prevention and HIV/drug treatment services for homeless persons is strongly recommended.     

Fiscal Sustainability and Immigration in the Madrid Region

The growing number of immigrants in the Madrid region raises several questions concerning the welfare of future native generations. The debates shift from increasing concern about the congestion of public services like education or healthcare, to how immigration helps to ease tension in relation to financing those services and other benefits to the region's general welfare. In order to evaluate the global effect, our analysis uses a generational accounting method which is applied to different productivity, interest rate and growth scenarios. The results show that the impact of immigrants is positive, with intergenerational distribution towards the currently most active taxpayers.     

Voices of Nigerian Women Survivors of Trafficking Held in Italian Centres for Identification and Expulsion

This article examines the vicissitudes that affect the migration trajectories of many Nigerian women who experienced trafficking before arriving in Italy, and end up in Centers for Identification and Expulsion (CIE) for undocumented migrants. Their life stories, collected within the CIE of Ponte Galeria (Rome), revealed violence as “a rule of action” with which these women are obliged to cope with at different levels. Moreover, they highlighted the failure of traditional security approaches to human trafficking, and the necessity to rethink the measures adopted to ensure survivors' protection and rights. As it is conceived, the system of immigration control prevents the full guarantee of survivors' rights, often labelling them as “illegal migrants”. Finally, there is the need to extend protection to all survivors of human trafficking even if the crime against them has not happened in Italy.     

A new continuous distribution on the unit interval applied to modelling the points ratio of football teams

We introduce a new flexible distribution to deal with variables on the unit interval based on a transformation of the sinh–arcsinh distribution, which accommodates different degrees of skewness and kurtosis and becomes an interesting alternative to model this type of data. We also include this new distribution into the generalised additive models for location, scale and shape (GAMLSS) framework in order to develop and fit its regression model. For different parameter settings, some simulations are performed to investigate the behaviour of the estimators. The potentiality of the new regression model is illustrated by means of a real dataset related to the points rate of football teams at the end of a championship from the four most important leagues in the world: Barclays Premier League (England), Bundesliga (Germany), Serie A (Italy) and BBVA league (Spain) during three seasons (2011–2012, 2012–2013 and 2013–2014).     

Associations of Migrants in Spain: An Enquiry into Their Digital Inclusion in the “Network Society” in the 2010s

VOLUNTAS: International Journal of Voluntary and Nonprofit Organizations - This paper explores the way that associations of migrants in Spain (AMS) in the 2010 decade integrate into the Network...