Brazilian Digital Library of Theses and Dissertations

This paper relates and analyses the experience of various Brazilian institutions organized in a consortium with the aim of providing integration and unified access, via a web gateway, to full-text electronic theses already available at different Brazilian universities. The rise and impact of free electronic academic publishing on scientific communication and the development of science is analyzed. The results of a pilot programme, developed under the coordination of IBICT, as well as technical and technological aspects of information system models adopted, are presented. Aspects such as metadata sets and formats, protocols for automatic gathering of metadata, union catalogue databases, user interfaces and integration with other Brazilian STI systems, are analyzed. Finally, future developments and the enlargement of the Brazilian Digital Library of Theses and Dissertations are discussed.     

Does Media Consumption Make Us Happy? Evidence for Spain

This article concerns the study of the impact of media consumption on happiness in Spain using data from the fourth wave of the European Social Survey, distinguishing between watching TV, listening to the radio, reading newspapers, and using the Internet. A negative effect of TV watching was found on individual happiness, mainly among women; those with higher incomes; and those with paying jobs—that is, among those with a higher opportunity cost of time. However, this negative effect on happiness does not appear for radio listening, newspaper reading, or Internet usage.     

SEMDS: An R Package for Structural Equation Multidimensional Scaling

The aim of this article is to introduce the R package semds for structural equation multidimensional scaling. This methodology combines multidimensional scaling with latent variable features from structural equation modeling and is applicable to asymmetric and three-way input dissimilarity data. This key idea of this approach is that the input data are assumed to be imperfect measurements of a latent symmetric dissimilarity matrix. The parameter estimation is performed via an alternating least squares multidimensional scaling procedure that minimizes the stress. The latent dissimilarities are estimated as factor scores within a structural equation modeling framework. Applications shown in the article involve data associated with the banking crisis and data from avalanche research. The models fitted with the semds package are compared to related methods from multidimensional scaling. The R code to reproduce all the computations is provided in the supplementary materials.     

The longitudinal effect of the Aprender a Convivir (learning to live together) programme in childhood: the development of social competence / Efecto longitudinal del programa Aprender a Convivir en la infancia: desarrollo de la competencia social

Abstract

In the context of a changing society, strategies are required to eradicate the phenomenon of antisocial behaviour. The Aprender a Convivir universal prevention programme tries to provide such a response. This study attempts to test the effectiveness of the programme through a quasi-experimental long-term study carried out over three years in some nursery schools. Of the students who participated in this study (N = 784), those from the experimental group showed significant increases in social competence compared to the control group, and behavioural problems decreased, albeit not in any significant way. To draw conclusions about the effectiveness of the programme, further improvements are proposed to the design of the study.     

Viscoelasticity of blood and viscoelastic blood analogues for use in polydymethylsiloxane in vitro models of the circulatory system

The non-Newtonian properties of blood are of great importance since they are closely related with incident cardiovascular diseases. A good understanding of the hemodynamics through the main vessels of the human circulatory system is thus fundamental in the detection and especially in the treatment of these diseases. Very often such studies take place in vitro for convenience and better flow control and these generally require blood analogue solutions that not only adequately mimic the viscoelastic properties of blood but also minimize undesirable optical distortions arising from vessel curvature that could interfere in flow visualizations or particle image velocimetry measurements. In this work, we present the viscoelastic moduli of whole human blood obtained by means of passive microrheology experiments. These results and existing shear and extensional rheological data for whole human blood in the literature enabled us to develop solutions with rheological behavior analogous to real whole blood and with a refractive index suited for PDMS (polydymethylsiloxane) micro- and milli-channels. In addition, these blood analogues can be modified in order to obtain a larger range of refractive indices from 1.38 to 1.43 to match the refractive index of several materials other than PDMS.     

Reading strategies in Spanish developmental dyslexics

Cross-linguistic studies suggest that the orthographic system determines the reading performance of dyslexic children. In opaque orthographies, the fundamental feature of developmental dyslexia is difficulty in reading accuracy, whereas slower reading speed is more common in transparent orthographies. The aim of the current study was to examine the extent to which different variables of words affect reaction times and articulation times in developmental dyslexics. A group of 19 developmental dyslexics of different ages and an age-matched group of 19 children without reading disabilities completed a word naming task. The children were asked to read 100 nouns that differed in length, frequency, age of acquisition, imageability, and orthographic neighborhood. The stimuli were presented on a laptop computer, and the responses were recorded using DMDX software. We conducted analyses of mixed-effects models to determine which variables influenced reading times in dyslexic children. We found that word naming skills in dyslexic children are affected predominantly by length, while in non-dyslexics children the principal variable is the age of acquisition, a lexical variable. These findings suggest that Spanish-speaking developmental dyslexics use a sublexical procedure for reading words, which is reflected in slower speed when reading long words. In contrast, normal children use a lexical strategy, which is frequently observed in readers of opaque languages.     

Egocentrismo espacial: concepto y procesos implicados

Resumen

En este artículo se estudia el concepto de egocentrismo espacial en una muestra de 47 niños entre 4 y 13 años, a través de un diseño transversal. Los resultados demuestran que los niños tienen capacidad de ponerse en el punto de vista del observador desde el período preescolar. Por otra parte, la capacidad de construir otras perspectivas con varios objetos, teniendo en cuenta las relaciones entre ellos, comienza a desarrollarse a partir de los 6 años en estrecha relación con la edad y el nivel de desarrollo.     

Reproducibility of upper leg EMG frequency content during cycling

Reproducibility of frequency content from surface electromyography (sEMG) signals has not been assessed and it is unknown if incremental load testing design could affect sEMG in cycling. The goals of this study were to assess the reproducibility of measures from sEMG frequency content between sessions and to compare these frequency components between a ramp and a step incremental cycling test. Eighteen cyclists performed four incremental load cycling tests to exhaustion. Two tests were performed using a step increment (load started at 100 W for 3 min followed by increments of 30 W every 3 min) and two were performed using a ramp increment (load started at 100 W for 1 min followed by increments of 30 W·min^?1). sEMG was monitored bilaterally for the rectus femoris and vastus lateralis throughout the tests and converted into overall activation (whole signal bandwidth), high- and low-frequency contents. The reproducibility of the frequency content ranged from none to strong (ICC = 0.07–0.90). Vastus lateralis activation was larger at the step compared to the ramp test (P < 0.01), without differences for rectus femoris (P = 0.22–0.91) and for the high-frequency (P = 0.28–0.95) and low-frequency contents (P = 0.13–0.94). sEMG from vastus lateralis and rectus femoris presented none to strong reproducibility. Vastus lateralis is more activated in step test design.     

A model for the effective engagement of all stakeholders in engineering education and its pilot implementation

Methodologies for engineering learning and teaching (MELT) approach aims to enhance the attractiveness of education through science, technology, engineering and mathematics (STEM) among young people, while promoting awareness of future careers in these areas. To this end, students’ expectations are considered within university programmes, aiming to an increased engagement in STEM careers. To accomplish these goals, a new and integrated approach (MELT) is presented, involving the main stakeholders in both scientific education and society. An education framework is presented, providing guidelines for an improved collaborative approach to STEM education in the future. Results from the pilot implementation of MELT are presented, from a small-scale education parliament prototype. From these initial stage and results, it is seen that there is a need for a proper alignment of expectations from all involved stakeholders, concerning the engineering education towards society’s demands.