Birth order and the gender gap in educational attainment

Review of Economics of the Household - While studies of birth order effects on human capital formation for developed countries abound, less is known about these effects in a developing country...     

Modelling two types of heterogeneity in the analysis of student success

ABSTRACT

Student dropout is a worldwide problem, leading private and public universities in developed and underdeveloped countries to study the subject carefully or, as has recently been done, to analyse what drives student success. On this matter, different approaches are used to obtain useful information for decision-making. We propose a model that considers the enrolment date to the dropout or graduation date and also covariates to measure student success rates, to identify what the academic and non-academic factors are, and how they drive the student success. Our proposal assumes that there is one part of the population who is not at risk of dropping out, and that the part of the population at risk is heterogeneous, that is, we assume two types of heterogeneity. We highlight two advantages of our model: one is to identify the period of higher risk to dropout due to considering the academic survival time and the second is due to the inclusion of covariates that enable us to identify the characteristics linked to dropout. In this research, we also demonstrate the identifiability of the model and describe the estimation procedures. To exemplify the applicability of the approach, we use two real datasets.     

Carers and Professionals' Perspectives on Foster Care Outcomes: The Role of Contact

This study investigates the association between the contact of children or young people in care with their family, and the foster care placement evaluation (positive or negative) in Portugal. According to the perspectives of foster carers and service professionals' perceptions regarding children and young people's reactions, during and after the visits, are measured. Utilizing a quantitative approach, two fostering services teams and 140 foster carers completed questionnaires, which had 212 children in common. Results indicated that despite the importance of continued contact, especially for children and their parents, it was not determined to be essential to long-term placement. On one hand, there was the perception that a high percentage of children expressed positive reactions during and after the visit, while on the other hand, this didn't influence the perception of placement success. This study also showed significant differences between foster carers' and the professionals' perceptions on several dimensions of foster care, especially the children's reactions during visits. These differences need to be further analyzed in future research and the outcomes used to help improve contact management.     

Production planning and control as a tool for eco-efficency improvement and environmental impact reduction

The environmental impacts of industrial activity are an increasing concern amongst firms and their stakeholders. As a result, companies around the world have been exploring new tools to diminish the adverse impact of their activities on the environment. Eco-efficiency has played an essential role in this scenario, as companies are continuously seeking to produce more while utilizsing fewer resources and minimising adverse effects on the environment. The literature includes several initiatives to improve eco-efficiency and to reduce the environmental impact of manufacturing operations, but the use of production planning and control (PPC) activities to accomplish these goals has rarely been considered. Therefore, to contribute to the assessment of this issue, this paper proposes to integrate environmental concepts and actions as part of the PPC execution; therefore, they could also be applied to minimise environmental impacts, resulting in an increase in the eco-efficiency level of a company. The practical utilisation of the suggested procedure was confirmed using a case study where the procedure was successfully applied to a make-to-order firm, where a simplified version of a workload control (WLC) form of PPC was in use. As a result, incorporating environmental considerations into the WLC practices enabled the eco-efficiency level of the designated production area to increase by 42%, while the environmental impact of production was reduced by 13%.     

The struggle for the state and the politics of belonging in contemporary Angola, 1975–2015

On the occasion of the 40th anniversary of Angola’s independence, this essay revisits key dimensions of the country’s postcolonial trajectory through the prism of the complex politics of the nationalist struggle and the first decades of self-rule. Its goal is to provide a series of reflections, mostly centred on the MPLA regime, rather than a comprehensive treatment of all political actors in Angolan politics of recent decades. It argues, firstly, that Angola’s trajectory from independence to the end of the country’s long civil war in 2002 was powerfully conditioned by the structural legacies of late colonialism, the associated intra-nationalist politics and the particular circumstances of the end of empire in 1975. To these legacies, the essay adds the (constrained, but real) choices made by Angolan decision-makers in terms of institutional consolidation, the management of the economy and state–society relations. Secondly, the essay outlines the extent to which the MPLA’s 2002 victory against UNITA in the country’s civil war did away with the fragmentation that had characterised Angolan politics since the 1960s. The clashing, indeed mutually exclusionary, nationalist projects that had jostled for control of the Angolan state were replaced by a would-be hegemonic political force with a strong sense of legitimacy and a self-defined project of postwar nation building. The key question for the contemporary study of Angola – and one that the oil-fuelled politics of the national reconstruction era provided plenty of reflection on – is the extent to which the MPLA’s postwar vision can supersede the country’s historical divisions and provide the population with both the material prosperity it yearns for and a shared understanding of belonging.     

Feasibility Study on the Use of Probabilistic Migration Modeling in Support of Exposure Assessment from Food Contact Materials

The use of probabilistic approaches in exposure assessments of contaminants migrating from food packages is of increasing interest but the lack of concentration or migration data is often referred as a limitation. Data accounting for the variability and uncertainty that can be expected in migration, for example, due to heterogeneity in the packaging system, variation of the temperature along the distribution chain, and different time of consumption of each individual package, are required for probabilistic analysis. The objective of this work was to characterize quantitatively the uncertainty and variability in estimates of migration. A Monte Carlo simulation was applied to a typical solution of the Fick's law with given variability in the input parameters. The analysis was performed based on experimental data of a model system (migration of Irgafos 168 from polyethylene into isooctane) and illustrates how important sources of variability and uncertainty can be identified in order to refine analyses. For long migration times and controlled conditions of temperature the affinity of the migrant to the food can be the major factor determining the variability in the migration values (more than 70% of variance). In situations where both the time of consumption and temperature can vary, these factors can be responsible, respectively, for more than 60% and 20% of the variance in the migration estimates. The approach presented can be used with databases from consumption surveys to yield a true probabilistic estimate of exposure.     

Influence diagnostics in the tobit censored response model

In this article, we develop influence diagnostic tools for the tobit model. Specifically, we discuss global influence methods based on the Cook distance and residuals with envelopes, and total and conformal local influence techniques. In order to analyze the sensitivity of the maximum likelihood estimators of the parameters of the model to small perturbations on the assumptions of the model and/or data, we consider several perturbation schemes, such as case-weight and response perturbations. Finally, we illustrate the developed methodology by means of a real data set.     

Factors Influencing Voluntary Disclosure in the Annual Reports of Portuguese Foundations

The aim of this paper is to examine the influence of Portuguese Foundation’s characteristics on their annual report disclosure practices. Data were collected from 142 Foundations in Portugal, which represents 50.9% of the Portuguese foundational sector. Supported by a Structural Equation Model (SEM), this study evaluates cause–effect relationship between Voluntary Disclosure, Board Structure, Organizations’ Characteristics and the existence of Auditing. Findings reveal that Organizations’ Characteristics influence the forms of Auditing, and on its turn, Auditing has a positive indirect impact on Voluntary Disclosure. Contrary to expectations, Board Structure does not affect Voluntary Disclosure. This paper fills a void in the literature by examining the impact of Foundations’ characteristics on their voluntary disclosure of financial and non-financial information.