Peer effects, unobserved factors and risk behaviours: an analysis of alcohol abuse and truancy among adolescents

The objective of this paper is to examine the factors which affect alcohol abuse and truancy among adolescents. We propose a new theoretical specification in which alcohol abuse and truancy appear as derived demands, given that they condition peer group and family acceptance, and we introduce unobserved individual effects that can influence both behaviours. Empirically, our paper develops an analysis where, after controlling for the existence of unobserved individual factors affecting both decisions, we test for peer influences. Our results first show evidence that alcohol abuse and truancy share unobserved factors affecting both decisions, and then confirm the existence of significant peer group influences on these two deviant behaviour

Involvement of advanced glycation end products in the pathogenesis of diabetic complications: the protective role of regular physical activity

Advanced glycation end products (AGEs) may play an important role in the pathogenesis of chronic diabetic complications and in the natural process of biological aging. In fact, maintained hyperglycaemia favours the formation of AGEs at the tissue level in diabetic patients, which may influence the triggering of different chronic pathologies of diabetes such as retinopathy, nephropathy, neuropathy and macro- and micro-vascular diseases. Moreover, the literature has also demonstrated the involvement of AGEs in biological aging, which may explain the accelerated process of aging in diabetic patients. The practice of regular physical activity appears to positively influence glycaemic control, particularly in type 2 diabetes mellitus patients. This occurs through the diminution of fasting glycaemia, with a consequent reduction of glycation of plasmatic components suggested by the normalisation of HbA1c plasmatic levels. This exercise-induced positive effect is evident in the blood of diabetic patients and may also reach the endothelium and connective tissues of different organs, such as the kidneys and eyes, and systems, such as the cardiovascular and nervous systems, with a local reduction of AGEs production and further deceleration of organ dysfunction. The aim of this paper was to review the literature concerning this topic to coherently describe the harmful effects of AGEs in organ dysfunction induced by diabetes in advanced age as well as the mechanisms behind the apparent protection given by the practice of regular physical

Effect of an electric field within microscopy focused ion beam (FIB) between manipulator sharp and the ion trap of the electron detector

"The manipulation of samples with micro manipulators sharps in the normal axis to the observation plane is practically blind in microscopy focused ion beam (FIB) mono beam. The application of a negative potential to the manipulator sharp has been considered, which causes differences of electrical potential between the detector and the sample holder, generating an electric field between the sharp and the sample. This makes the electrons, aside the sample, undergo a greater deflection, reflecting in poorer contrast image. This deflection depends on a great extension of the sample holder height between the micromanipulator sharp, voltage deflector, q/m electron factor and electron acceleration.

El abuso juvenil de alcohol: estimaciones count data

En este trabajo analizamos los determinantes del consumo abusivo de alcohol entre los jóvenes españoles. Con este fin, adoptamos un enfoque psicosocial que formulamos empíricamente estimando diversos modelos count data (Poisson, binomial negativo, Poisson con exceso de ceros y binomial negativo con exceso de ceros) a partir de la información disponible en las tres olas de la Encuesta sobre Drogas a la Población Escolar correspondientes a 1996, 1998 y 2000. Los resultados muestran que los factores físicos (sexo y edad), así como los determinantes psicosociales (entornos familiar, escolar y local) son clave en la explicación de la probabilidad y la frecuencia de consumo abusivo de alcohol.Determinantes psicosociales, consumo abusivo de alcohol, jóvenes, modelos count data.

Lesões celulares do músculo esquelético induzidas pelo exercício físico

Dissertação de Doutoramento em Ciência do Desporto, área de especialização em Biologia do Desporto, apresentada à Faculdade de Ciências do Desporto e de Educação Física da Universidade do Port

Reducing attrition and dropout in e-learning: the development of a course design model

Worldwide, the e-Learning market has been growing faster and faster [1], but not without some disappointments [2]. One of the biggest setbacks regarding e-Learning is that related to the high rates of attrition [3] that leads to frustration [4] [5] [6] and, eventually, to dropout. Student dropout rates for e- Learning are 15–20% higher than traditional face-to-face courses [7]. For all reasons that might have an influence in attrition and dropouts in e-Learning we argue that course design is the key. Therefore, the main question is how to design e-Learning courses with lower attrition and dropout rates? The primary objective of this Erasmus+ Strategic Partnership for adult education research project, is to produce a model to assist e-Learning course developer’s decisions based on scientific literature that will lead to the development of an implementation prototype. The specific objectives are: (i) to understand the relationship between course design in e-Learning with attrition and dropout; (ii) to identify dropout reasons in relations to course design in e-Learning; (iii) to validate course design as a problem affecting dropout in e-Learning; and (iv) to propose a decision-making course design model for a future prototype. As a methodological approach, we will use Development Research [8]. This methodology involves an interrelationship between theory and practice to create an effective intervention to a specific problem, which requires not only its analysis but also the construction of a particular process or product. We see the Development Research as a cyclical process of designing, testing, and redesigning, always incorporating feedback provided by all the actors. This process leads to new theoretical and empirically founded products, whereby the researchers get new insights, ultimately bringing the state of the art a step forward. Outgoing from the creation of our e-Learning prototype, we will collect information in a participatory manner, justifying the choices that will be integrated into the development process/product, and creating the conditions for permanent feedback to improve the product as well as the educational process. Thus, the research process is less driven on obtaining a descriptive knowledge; instead, it is more focused on the need to get, from the feedback on the tasks and the product development, information about how different aspects of the problem can be solved. According to our research plan, we firstly review the state of the art, following a systematic review [9], which is “designed to locate, appraise and synthesize the best available evidence relating to a specific research question to provide informative and evidence-based answers” [10]. Secondly, and after accessing the relationship between course design in e-Learning with attrition and dropout in previous step, we propose a decision-making model for an implementation prototype. Third, the prototype is tested and improved based on data collected, including attrition and dropout. Fourth, a functional product is released, providing the necessary mechanics for improvement based on continuous data collection.The research leading to these results has received funding from the European Community's ERASMUS+ PROGRAMME under grant agreement no. 2015-1-TR01-KA204-021954 “Better e- Learning for All”

Computerized respiratory sounds in paediatrics: a systematic review

Background Diagnosing and monitoring of children with respiratory disorders is often challenging. Respiratory sounds (RS) are simple, non-invasive and universally available measures that are directly related to movement of air, within the tracheobronchial tree. Thus, RS may be valuable indicators of respiratory health, their characteristics in the paediatric population are scattered in the literature and not systematized. Aim Systematically review the different acoustic RS properties in healthy children and in children with different respiratory disorders. Methods: MEDLINE, EMBASE, AMED and CINHAL databases were searched on Sept 2020. One author extracted data and two independently assessed the quality of the articles using the National Heart Lung and Blood Institute quality assessment tool. Results Twenty-eight studies were included with a total 2032 participants (44% with a respiratory condition, such as asthma, bronchiolitis, cystic fibrosis, presence of wheezing and non-specified low respiratory tract infections). A high heterogeneity in the procedures, outcomes and outcome measures used was found. Healthy participants showed lower values of F50 (from 194 ± 26 to 521 ± 18Hz) than those with asthma (from 140 ± 8 to 769 ± 85Hz) or bronchiolitis (from 100 to 80Hz). F50 tend to increase with provocation tests (136 ± 9 to 909 ± 81Hz) and decrease with treatments (128 ± 6 to 781 ± 57Hz). Wheeze rates ranged from 0 to 24.7 ± 25% on asthmatic participants. Crackles findings ranged from 6% on people with recurrent wheezing to 30.8% in middle lobe atelectasis. Conclusion RS show different acoustic properties in healthy children vs with different respiratory disorders and thus may be useful in the diagnostic and monitoring on paediatrics.publishe

Atividade lítica de células natural "killer" durante a infecção pelo HIV-1 em indivíduos brasileiros

Natural killer cells are increasingly being considered an important component of innate resistance to viruses, but their role in HIV infection is controversial. Some investigators have found that natural killer cells do not confer a protective effect during the progression of HIV disease, whereas others have shown that natural killer cells may be protective and retard the progression of the disease, either through their lytic activity or by a chemokine-related suppression of HIV replication. In this study, we analyzed functional alterations in the activity of natural killer cells during HIV-1 infection using a natural killer cells activity assay with K562 cells as targets. RESULTS: Our results show that the activity of natural killer cells decreases only in the advanced phase of HIV infection and when high (40:1) effector cell-target cell ratios were used. The depression at this stage of the disease may be related to increased levels of some viral factors, such as gp120 or gag, that interfere with the binding capacity of natural killer cells, or to the decreased production of natural killer cells -activity-stimulating cytokines, such as IFN-a and IL-12, by monocytes, a subset of cells that are also affected in the late stage of HIV infection. The data suggest that decreased natural killer cells cell activity may contribute to the severe impairment of the immune system of patients in the late stages of HIV infection.As células "natural killer" são consideradas importante componente da resistência inata às viroses, mas seu papel na infecção pelo HIV é controverso. Alguns investigadores verificaram que as células "natural killer" não possuíam qualquer efeito protetor durante a progressão para doença, enquanto outros têm mostrado que as mesmas podem ser protetoras e retardar a progressão para doença, tanto devido à sua ação lítica como pela supressão por quimocinas. Em nosso estudo, analisamos as alterações funcionais na atividade durante infecção pelo HIV-1 usando ensaio com células K562 como alvo. Os resultados mostraram que a atividade "natural killer" está diminuída somente nas fases mais avançadas da doença e somente quando foi utilizar um número elevado de (40:1) células efetoras-alvos. A diminuição da atividade neste estágio da doença pode estar relacionada com a imunossupressão grave; a presença de alguns fatores virais, como a gp120 e gag, que interferem como a capacidade de ligação das células "natural killer"; ou a redução da produção de citocinas que estimulam a atividade "natural killer", como IFN-a e IL-12, por monócitos, uma subpopulação de células que são afetadas somente nos estágios mais avançados da infecção HIV. Assim, fica sugerido que a diminuição da atividade "natural killer" pode contribuir para alterações no sistema imune de pacientes nas fases avançadas da infecção HIV