Testing inference in heteroskedastic linear regressions: a comparison of two alternative approaches

We consider the issue of performing testing inferences on the parameters that index the linear regression model under heteroskedasticity of unknown form. Quasi-t test statistics use asymptotically correct standard errors obtained from heteroskedasticity-consistent covariance matrix estimators. An alternative approach involves making an assumption about the functional form of the response variances and jointly modelling mean and dispersion effects. In this paper we compare the accuracy of testing inferences made using the two approaches. We consider several different quasi-t tests and also z tests performed after estimated generalized least squares estimation which was carried out using three different estimation strategies. The numerical evidence shows that some quasi-t tests are typically considerably less size distorted in small samples than the tests carried out after the jointly modelling of mean and dispersion effects. Finally, we present and discuss two empirical applications.     

Analysis of the Better Life Index Trough a Cluster Algorithm

Social Indicators Research - This paper discusses some concepts attributed to the term well-being and different ways to measure it. Then we present an alternative approach based on clustering...     

Labour Market Policies: Welfare,Incomes, Employment

The — in some ways innovative — objective of this paper is the study of the dynamics of the disequilibria provoked by the emergence of involuntary unemployment in the labour market, and the role of the economic policy authorities (through welfare, incomes and employment policies), with the aim of discovering if there is an explicit or implicit consistency between the role of these authorities, their actions and the pursuit of maximum employment (or elimination of the disequilibria). We seek to show, in other words, whether the actions of the government authorities conform to their accepted meaning (the aim of reducing the disequilibria) or whether, on the contrary, it may not be possible to put forward a different interpretation, if sociopolitical variables are introduced into the analysis, thus placing in the foreground different and alternative objecties such as “conflict control” and/or the reaching of a consensus between the different social partners. The paper therefore begins by analysing separately the historical-theoretical characteristics of the individual policies considered — welfare, incomes and employment — in their evolution (with particular reference to the last two decades), and then attempts an interpretative key in synthesis, by resorting to a specific model derived from the theories of disequilibria.     

Labour Economics: History and Theory

Abstract. In recent years, labour economics has been the area of study of most interest to economists, both from the theoretical and practical perspectives. The new field of labour microeconomics and the resultant new approaches that have arisen are a fundamental part of what has recently been called ‘microeconomic foundations’. Despite the newness of this topic, recent developments are in fact the result of phenomena recognized throughout the history of economic thought. This paper begins by analyzing the historical and theoretical origins of labour economics, and provides an overview of labour economics theory during the 1960s. 1970s and 1980s. It goes on to examine the relation between the labour market and technological innovation, and labour policy measures at the microeconomic and macroeconomic levels. Finally, it underscores the need for a theoretical construct that sets Keynesian and neoclassical explanations of unemployment in the same framework as demographic, social, institutional, time and economic factors.     

La violence politique totale: quatre vertus sociologiques paradoxales

Prenant acte du fait que le champ des sciences sociales est incontestablement perturbé dans sa capacité à expliquer la résurgence des formes de violence les plus radicales dans le sillage de ce qu'il est désormais convenu d'appeler ‘les évènements du 11 septembre 2001’, nous poserons l'hypothèse suivante: loin de constituer un phénomène nouveau, ces évènements nous invite avec réflexivité à reconsidérer des questions sociologiques fondamentales telles que la forclusion de la violence dans les sociétés à modernité tardive, la rationalité et les nouvelles subjectivités émergentes, la gouvernabilité des sociétés modernes et, en conclusion, le monopole explicatif des sciences sociales, autant de vertus sociologiques paradoxales.     

An Intertemporal Analysis of Development Policies in the EU

In this paper, we focus on the effects of EU structural transfer programs on the evolution of the EU less developed economies. We develop a two-sector endogenous growth model of private and public physical capital and human capital accumulation in which the public sector and the current account balances play a crucial role. This model is applied to Portugal. Simulation results suggest that structural programs will bring Portuguese GDP per capita to 63.7% of the EU average (up from around 54% in the last two decades), thereby greatly contributing to the process of real convergence of the Portuguese economy to EU standards. Additional transfers, primarily targeted at infrastructure development, are necessary, however, if a greater degree of real convergence is to be achieved. Furthermore, the impact of transfers on public deficits, the current account, and real exchange rates might adversely affect the long run requirements of nominal convergence and might exacerbate the need for budgetary restraint in Portugal. Accordingly, a relaxation of domestic matching fund requirements might be desirable.     

Manual bamboo cutting tool

The paper presents the development of a cutting tool guide, specifically for the harvest of bamboo. The development was made based on precepts of eco-design and ergonomics, for prioritizing the physical health of the operator and the maintenance of the environment, as well as meet specific requirements of bamboo. The main goal is to spread the use of bamboo as construction material, handicrafts, among others, from a handy, easy assembly and material available tool.     

Methodological proposal for occupational health and safety actions in research laboratories with nanotechnologies activities

Nanotechnologies is a multidisciplinary set of techniques to manipulate matter on nanoscale level, more precisely particles below 100 nm whose characteristic due to small size is essentially different from those found in macro form materials. Regarding to these new properties of the materials there are knowledge gaps about the effects of these particles on human organism and the environment. Although it still being considered emerging technology it is growing increasingly fast as well as the number of products using nanotechnologies in some production level and so the number of researchers involved with the subject. Given this scenario and based on literature related, a comprehensive methodology for health and safety at work for researching laboratories with activities in nanotechnologies was developed, based on ILO structure guidelines for safety and health at work system on which a number of nanospecific recommendations were added to. The work intends to offer food for thought on controlling risks associated to nanotechnologies.     

Structuring software anthropometric variables on CD Rom as a facilitator of the process of design of work situations

The environment where everyday activities are developed, these should be appropriate and the individual who will execute them, for greater efficiency of their work and even if you feel safe, comfortable and satisfied when interacting with that space, expending less energy to this interaction. Given this context, this study aims to structure a software with the results obtained in the field, from anthropometric measure to subsidize the furniture industry in manufacturing of furniture, definition work situations, considering the different anthropometric measurements made between 2001 and 2010, using data from this sample of adults aged 18 to 65 years old and children between 6 and 11 years old. It was convenient to make the software with a site, only instead of staying on the Web has been recorded on CD Rom. Tests with the prototype allow navigation through the structure of the software. The data needed to implement the remaining modules were also raised. Issues related to system layout and usability of the interface also were not considered, because it is an initial prototype.