Atividades digitais através do Edilim no 1º ciclo do ensino básico : resultados de uma investigação na prática de ensino supervisionada

As TIC fazem parte fundamental da nossa vida sendo indispensáveis para as atividades diárias de cada cidadão. Naturalmente, no sistema educativo as TIC também transformam o dia a dia na comunidade educativa. Neste sentido, a formação dos jovens em TIC para adquirirem competências digitais é um aspeto fundamental para os preparar para a sociedade atual e que deve ser inicializada através da sua utilização em contexto de sala de aula. O Relatório de Estágio pretendeu averiguar as potencialidades da utilização das TIC e o impacto, em particular, da implementação de um software de autor «EdiLim» através dos seguintes objetivos: promover a utilização de recursos digitais nas aprendizagens do 1.° Ciclo; identificar qual a utilização das TIC que os professores fazem no contexto de sala de aula; implementar atividades pedagógicas com atividades através do EdiLim; avaliar o contributo para as aprendizagens através da utilização do EdiLim. Esta investigação foi desenvolvida no âmbito da Prática de Ensino Supervisionada no 1º Ciclo do Ensino Básico (PES1CEB), no 2º ano do Mestrado em Educação Pré-Escolar e Ensino do 1º Ciclo do Ensino Básico. A turma era constituída por 22 alunos com idades compreendidas entre os 9 e os 10 anos. A investigação assumiu um caráter qualitativo no qual se realizou uma abordagem de estudo de caso e de investigação-ação. O principal instrumento de recolha de dados consistiu na observação participada com recurso a registo fotográfico e notas de campo, tendo como participantes, para além da investigadora e dos alunos, a «Orientadora Cooperante» e o «Par Pedagógico». Houve ainda necessidade de realizar inquéritos por questionários aos alunos e entrevistas semiestruturadas à «Orientadora Cooperante» e a um professor do 1º CEB da Instituição, como forma de conhecer a opinião dos inquiridos e entrevistados face à utilização das TIC e de softwares educativos como recurso no Ensino Básico. Em suma, os resultados da investigação, através da triangulação de dados possibilitaram a perceção de que a utilização do EdiLim veio promover maiores e melhores níveis de motivação dos alunos, favorecendo o processo de ensino e de aprendizagem.info:eu-repo/semantics/publishedVersio

Bisphenol A exposure and cardiac electrical conduction in excised rat hearts

BACKGROUND: Bisphenol A (BPA) is used to produce polycarbonate plastics and epoxy resins that are widely used in everyday products, such as food and beverage containers, toys and medical devices. Human biomonitoring studies have suggested that a large proportion of the population may be exposed to BPA. Recent epidemiological studies have reported correlations between increased BPA urinary concentrations and cardiovascular disease; yet the direct effects of BPA on the heart are unknown. OBJECTIVES: The goal of our studies was to measure BPA\u27s effect (0.1-100 μM) on cardiac impulse propagation ex vivo, using excised whole hearts from adult rats. METHODS: We measured atrial and ventricular activation times during sinus and paced rhythms using epicardial electrodes and optical mapping of transmembrane potential. Atrioventricular activation intervals and epicardial conduction velocities were computed using recorded activation times. RESULTS: Cardiac BPA exposure resulted in prolonged PR segment and decreased epicardial conduction velocity (0.1 - 100 μM), prolonged action potential duration (1 - 100 μM) and delayed atrioventricular conduction (10 - 100 μM). Importantly, these effects were observed after acute exposure (≤ 15 min), underscoring the potential detrimental effects of continuous BPA exposure. The highest BPA concentration used (100 μM) resulted in prolonged QRS intervals, dropped ventricular beats and eventually resulted in complete heart block. CONCLUSIONS: Our results show that acute BPA exposure slows electrical conduction in excised hearts from female rats. These findings emphasize the importance of examining BPA\u27s effect on heart electrophysiology and determining whether chronic in vivo exposure can cause/exacerbate conduction abnormalities in patients with pre-existing heart conditions and other high-risk populations

Generation and escape of local waves from the boundary of uncoupled cardiac tissue

We aim to understand the formation of abnormal waves of activity from myocardial regions with diminished cell-to-cell coupling. In route to this goal, we studied the behavior of a heterogeneous myocyte network in which a sharp coupling gradient was placed under conditions of increasing network automaticity. Experiments were conducted in monolayers of neonatal rat cardiomyocytes using heptanol and isoproterenol as means of altering cell-to-cell coupling and automaticity respectively. Experimental findings were explained and expanded using a modified Beeler-Reuter numerical model. The data suggests that the combination of a heterogeneous substrate, a gradient of coupling and an increase in oscillatory activity of individual cells creates a rich set of behaviors associated with self-generated spiral waves and ectopic sources. Spiral waves feature a flattened shape and a pin-unpin drift type of tip motion. These intercellular waves are action-potential based and can be visualized with either voltage or calcium transient measurements. A source/load mismatch on the interface between the boundary and well-coupled layers can lock wavefronts emanating from both ectopic sources and rotating waves within the inner layers of the coupling gradient. A numerical approach allowed us to explore how: i) the spatial distribution of cells, ii) the amplitude and dispersion of cell automaticity, iii) and the speed at which the coupling gradient moves in space, affects wave behavior, including its escape into well-coupled tissue.Comment: 28 pages, 10 figures, submitted to Biophysical Journa

Evolution of spiral and scroll waves of excitation in a mathematical model of ischaemic border zone

Abnormal electrical activity from the boundaries of ischemic cardiac tissue is recognized as one of the major causes in generation of ischemia-reperfusion arrhythmias. Here we present theoretical analysis of the waves of electrical activity that can rise on the boundary of cardiac cell network upon its recovery from ischaemia-like conditions. The main factors included in our analysis are macroscopic gradients of the cell-to-cell coupling and cell excitability and microscopic heterogeneity of individual cells. The interplay between these factors allows one to explain how spirals form, drift together with the moving boundary, get transiently pinned to local inhomogeneities, and finally penetrate into the bulk of the well-coupled tissue where they reach macroscopic scale. The asymptotic theory of the drift of spiral and scroll waves based on response functions provides explanation of the drifts involved in this mechanism, with the exception of effects due to the discreteness of cardiac tissue. In particular, this asymptotic theory allows an extrapolation of 2D events into 3D, which has shown that cells within the border zone can give rise to 3D analogues of spirals, the scroll waves. When and if such scroll waves escape into a better coupled tissue, they are likely to collapse due to the positive filament tension. However, our simulations have shown that such collapse of newly generated scrolls is not inevitable and that under certain conditions filament tension becomes negative, leading to scroll filaments to expand and multiply leading to a fibrillation-like state within small areas of cardiac tissue.Comment: 26 pages, 13 figures, appendix and 2 movies, as accepted to PLoS ONE 2011/08/0

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Glass art.https://hsrc.himmelfarb.gwu.edu/artshow_gallery_2014/1072/thumbnail.jp

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Glass art.https://hsrc.himmelfarb.gwu.edu/artshow_gallery_2014/1071/thumbnail.jp

Building Valveless Impedance Pumps From Biological Components: Progress and Challenges

Valveless pumping based on Liebau mechanism entails asymmetrical positioning of the compression site relative to the attachment sites of the pump\u27s elastic segment to the rest of the circuit. Liebau pumping is believed to play a key role during heart development and be involved in several other physiological processes. Until now studies of Liebau pump have been limited to numerical analyses, modeling, experiments using non-biological elements, and a few indirect measurements. This review aims to stimulate experimental efforts to build Liebau pumps using biologically compatible materials in order to encourage further exploration of the fundamental mechanisms behind valveless pumping and its role in organ physiology. The covered topics include the biological occurrence of Liebau pumps, the main differences between them and the peristaltic flow, and the potential uses and body sites that can benefit from implantable valveless pumps based on Liebau principle. We then provide an overview of currently available tools to build such pumps and touch upon limitations imposed by the use of biological components. We also talk about the many variables that can impact Liebau pump performance, including the concept of resonant frequencies, the shape of the flowrate-frequency relationship, the flow velocity profiles, and the Womersley numbers. Lastly, the choices of materials to build valveless impedance pumps and possible modifications to increase their flow output are briefly discussed