The effect of variability and carryover on average bioequivalence assessment: a simulation study

The purpose of this study was to evaluate the effect of residual variability and carryover on average bioequivalence (ABE) studies performed under a 22 crossover design. ABE is usually assessed by means of the confidence interval inclusion principle. Here, the interval under consideration was the standard 'shortest' interval, which is the mainstream approach in practice. The evaluation was performed by means of a simulation study under different combinations of carryover and residual variability besides of formulation effect and sample size. The evaluation was made in terms of percentage of ABE declaration, coverage and interval precision. As is well known, high levels of variability distort the ABE procedures, particularly its type II error control (i.e. high variabilities make difficult to declare bioequivalence when it holds). The effect of carryover is modulated by variability and is especially disturbing for the type I error control. In the presence of carryover, the risk of erroneously declaring bioequivalence may become high, especially for low variabilities and large sample sizes. We end up with some hints concerning the controversy about pretesting for carryover before performing ABE analysis.     

Use of exponential power distributions for mixture models in the presence of covariates

In this paper, we present a Bayesian analysis of exponential power mixture models in the presence of a covariate. Considering Gibbs sampling with MetropolisHastings algorithms, we obtain Monte Carlo estimates for the posterior quantities of interest.     

Between two Beneditos: enslaved wet-nurses amid slavery’s decline in southeast Brazil

ABSTRACT

This article discusses a series of questions related to the presence of enslaved women, female slaves working toward contractual or bequeathed freedom, and freedwomen in the domestic sphere in the final years of slavery in Brazil, with an initial emphasis on the contradictions between medical and sanitarian discourses that promoted a new, bourgeois vision of the home and the continued existence of the master-slave relationship and tutelary relations derived therefrom in the most intimate spaces of wealthy households in the cities and towns of the country’s coffee-growing southeast. The article also seeks to reconstruct the perspective of these captive and servant-class women at the moment of slavery’s extinction, thus providing a new perspective on the latter process by noting how the abolition of slavery was conditioned by the gendering of household work. A reconstruction of the life of Ambrosina, a slave woman rented out by her owner to serve another family as a wet nurse, then accused of murder after the death of her young charge, is the means by which these contributions are made.     

Bootstrap Bartlett correction in inflated beta regression

The inflated beta regression model aims to enable the modeling of responses in the intervals (0, 1], [0, 1), or [0, 1]. In this model, hypothesis testing is often performed based on the likelihood ratio statistic. The critical values are obtained from asymptotic approximations, which may lead to distortions of size in small samples. In this sense, this article proposes the bootstrap Bartlett correction to the statistic of likelihood ratio in the inflated beta regression model. The proposed adjustment only requires a simple Monte Carlo simulation. Through extensive Monte Carlo simulations the finite sample performance (size and power) of the proposed corrected test is compared to the usual likelihood ratio test and the Skovgaard adjustment already proposed in the literature. The numerical results evidence that inference based on the proposed correction is much more reliable than that based on the usual likelihood ratio statistics and the Skovgaard adjustment. At the end of the work, an application to real data is also presented.     

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...     

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.     

Is there enough information to calculate the financial benefits of ergonomics projects?

Many authors studied work situations and, mainly, ergonomics projects concerning the financial benefit point of view. At the same time seems to be little information available concerning these financial benefits in manufacturing companies' processes. The aim of this article is to identify if there enough information available within a company to quantify the financial benefits of an ergonomic project. The study was applied on two manufacturing companies, one in Brazil and other in Portugal. A literature review based checklist and a manager interview was applied on each company in order to identify if the information was available and how were been used. The two companies have revealed a good quantity of available information regarding ergonomics benefit calculation. The interviews showed that managers are not aware of the financial savings possibility with investments in ergonomics projects.