393 research outputs found

    Movimento Vertical e Balístico

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    Este trabalho é destinado aos profissionais da área de física e assim como aos estudantes de Física, e tem como objetivo desenvolver aulas sobre Movimento vertical e Movimento Balístico. Tal trabalho representa uma proposta de uma aula para os alunos do primeiro ano Ensino Médio das redes públicas e particulares, que tenham conhecimento sobre Movimento Retilíneo Uniforme (M.R.U.) e Movimento Retilíneo Uniformemente Variado (M.R.U.V.) e vetores. Utilizando equipamentos do cotidiano numa aula teórica de física podemos introduzir o conceito experimental, mostrando para os alunos como o conceito físico pode ser aplicado matematicamente. Com o auxílio desses materiais, fica mais fácil para o aluno visualizar os fenômenos físicos e com uma câmera digital, por exemplo, estes movimentos podem ser filmados e serem uma fonte rica de informações. Tendo em vista as dificuldades dos alunos em visualizar os movimentos e a ausência de procedimentos experimentais no Ensino Médio, este trabalho introduz o conceito experimental para análise de dados obtidos através de imagens filmadas e superpostas com programas de computador. O referencial metodológico foi baseado nas teorias de Lev Vigotsky, onde coloca o professor como mediador no processo de aprendizagem

    Comunicação política no Facebook e previsão eleitoral - Análise de big data da eleição presidencial brasileira de 2018 no Brasil: Big data analysis of the 2018 Brazilian presidential election Brazil

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    This article aims to understand how the quantitative analysis of political communication in social media, through indicators of engagement to the political speech, is able to predict the electoral outcome. This study is a big data analysis of the first round of the 2018 presidential election in Brazil. Specifically, around 10,000 posts were collected from official Facebook campaign pages between June 1 and October 7, 2018. Regarding voting intent, a series of daily representative of the Brazilian population opinion polls were conducted for the same period. In order to understand whether there is a causal relationship between candidate engagement on Facebook and voting intent, predictive analysis was performed by testing two empirical approaches: one with aggregated data and the other with 90 multiple linear regression prediction models. We conclude the analysis by comparing the actual election results with all predictive models. The results showed that both the aggregate and regressive approaches demonstrate that the candidate engagement rate on Facebook is a good electoral predictor. The results reinforce the theories that defend the relevance of data coming from political behaviour in social media as good electoral predictor.O presente artigo busca entender como a análise quantitativa da comunicação política nas mídias sociais, mediante indicadores de engajamento ao discurso de candidatos, é capaz de prever o resultado eleitoral. Trata-se de uma análise de big data do 1º turno do pleito presidencial de 2018 no Brasil. Concretamente, foram coletadas cerca de 10 mil postagens das páginas oficiais de campanha no Facebook entre 1 de junho e 7 de outubro de 2018. No que se refere à intenção de voto, foi realizada para o mesmo período uma série surveys de opinião com frequência diária, representativa da população brasileira. Com o fim de entender se há uma relação causal entre o engajamento ao candidato no Facebook e a sua intenção de voto, a análise preditiva foi realizada testando duas abordagens empíricas: uma com dados agregados e a outra com 90 modelos de previsão mediante regressão linear múltipla. Concluímos a análise comparando os resultados reais das eleições com todos os modelos preditivos. Os resultados mostraram que tanto a abordagem agregada quanto a regressiva demonstram que o índice de engajamento ao candidato no Facebook é um bom preditor eleitoral. Os resultados obtidos reforçam as teorias que defendem a relevância dos dados advindos do comportamento político nas mídias sociais como bons preditores eleitorais

    Two-dimensional multiscale entropy analysis: applications to image texture evaluation

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    Complexity measures, defined as measures of irregularity over time scales, are the subject of a growing number of studies as the information they reveal can find utility in a large field of applications. One of the most popular complexity measures is the multiscale entropy. Nevertheless, more and more algorithms dedicated to complexity analyses are proposed to improve the existing ones. However, such measures are available only for one-dimensional time series. For bidimensional data (images), no equivalent algorithm has been proposed to analyze irregularity over spatial scales. We herein introduce a new framework that extends the one-dimensional multiscale entropy (MSE1D) to the bidimensional case (MSE2D). Moreover, a variant of MSE2D is also ModMSE2D). The two new algorithms are tested as new texture analysis frameworks. They are applied to simulated and real data. Our results show that, compared with other existing texture analysis algorithms, MSE2D and ModMSE2D are suitable and powerful tools for image analysis and classification according to their texture patterns. While MSE2D is computationally faster than ModMSE2D, ModMSE2D is more robust to small image sizes. The two methods present interesting performances, and can be as useful as their unidimensional versions in two-dimensional applications

    Biomimetic phantom with anatomical accuracy for evaluating brain volumetric measurements with magnetic resonance imaging

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    Purpose: Brain image volumetric measurements (BVM) methods have been used to quantify brain tissue volumes using magnetic resonance imaging (MRI) when investigating abnormalities. Although BVM methods are widely used, they need to be evaluated to quantify their reliability. Currently, the gold-standard reference to evaluate a BVM is usually manual labeling measurement. Manual volume labeling is a time-consuming and expensive task, but the confidence level ascribed to this method is not absolute. We describe and evaluate a biomimetic brain phantom as an alternative for the manual validation of BVM. Methods: We printed a three-dimensional (3D) brain mold using an MRI of a three-year-old boy diagnosed with Sturge-Weber syndrome. Then we prepared three different mixtures of styrene-ethylene/butylene-styrene gel and paraffin to mimic white matter (WM), gray matter (GM), and cerebrospinal fluid (CSF). The mold was filled by these three mixtures with known volumes. We scanned the brain phantom using two MRI scanners, 1.5 and 3.0 Tesla. Our suggestion is a new challenging model to evaluate the BVM which includes the measured volumes of the phantom compartments and its MRI. We investigated the performance of an automatic BVM, i.e., the expectation–maximization (EM) method, to estimate its accuracy in BVM. Results: The automatic BVM results using the EM method showed a relative error (regarding the phantom volume) of 0.08, 0.03, and 0.13 (±0.03 uncertainty) percentages of the GM, CSF, and WM volume, respectively, which was in good agreement with the results reported using manual segmentation. Conclusions: The phantom can be a potential quantifier for a wide range of segmentation methods

    Water infiltration in the Brazilian tropical savanna: the case of Cerrado típico

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    A savana brasileira, regionalmente conhecida como Cerrado é uma importante fonte de água devido à sua posição espacial na região de terras de alta altitude conhecida como Planalto Central do Brasil. No entanto, o funcionamento hidrológico desse complexo conjunto de ecossistemas e duas inúmeras variações são pouco compreendidos. O objetivo do presente estudo foi caracterizar a permeabilidade da superfície do solo à água em um dos mais comuns tipos de vegetação do Cerrado: o Cerrado típico que é um tipo de savana. Foram medidas a capacidade de infiltração usando o infiltrômetro  Mini-Disk (n = 15) e a resistência do solo à penetração usando o penetrômetro Stolf (n = 7) em um Latossolo sob Cerrado típico localizado em Brasília (Planaltina), Distrito Federal, Brasil. Os resultados indicaram uma alta capacidade de infiltração sob Cerrado típico que pode estar associada à uma baixa resistência do solo à penetração. Este fato destaca a importância dos ecossistemas naturais sem distúrbio, no presente caso o Cerrado típico, como uma cobertura da terra que favorce processos hidrológicos que promovem a recarga do solo e a da água subterrânea que mantém a água nos corpos d´água e reservatórios da região.The Brazilian savanna, regionally known as Cerrado is an important water source due to its spatial position in the highlands known as Planalto Central of Brazil. Yet, the hydrological functioning of such complex ecosystems and its many variations is poorly understood. In this paper, we characterized the soil surface permeability to water under in one of the most common vegetation types: the Cerrado típico which is a type of savanna. In doing so, we measured infiltration capacity using the Mini-Disk infiltrometer (n = 15) and soil resistance to penetration using the Stolf penetrometer (n = 7) in a Latossolo (oxisol) under Cerrado típico located in Brasília (Planaltina), Distrito Federal, Brazil. Our  results indicated a high infiltration capacity under Cerrado típico which is potentially associated with a low penetration resistance. This fact might highlight the importance of the natural undisturbed ecosystems, in this case Cerrado típico, as a land-cover which favors hydrological processes which, in turn, promotes soil-groundwater recharge that are inportant to maintain water bodies and reservoirs in the region

    A collective autoethnography of coproduction in mental health research by academic researchers and young people in Brazil

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    Introduction Coproduction of mental health research and interventions involving researchers and young people is increasingly common. However, this model raises challenges, related, for instance, to communication, power and control. This paper narrates—from a collective first-person perspective—the lived experience of coproduction of a digital intervention by institutional researchers and young citizen researchers in Brazil. Method This study employed a collaborative autoethnographic methodology, utilising autobiographical data such as meeting recordings, individual notes and collective guided reflections on the coproduction process. Our analysis focused on challenges and solutions that arose during the process. Results Throughout the project, we created formal and informal mechanisms for accountability, transparency and fair inclusion of multiple voices. We engaged in mutual capacity-building, invested in building interpersonal knowledge, and implemented practices to reduce overload and promote equitable participation. Through ongoing reflection and readjustment in response to challenges, we progressively embraced more democratic and egalitarian values. The collective care invested in the process fostered synergy, trust, and intergroup friendship. Conclusion Our experience points to the value of creating a space for multiple research identities: the citizen young person and the institutional researcher, both of whom critically reflect on their roles in the research process. Our focus on coproduced care calls into question participation metaphors that represent the process via a single axis—young people—who linearly progress from minimal participation to full autonomy. Instead, our analysis highlights the importance of a social and caring bond that supports the radical co-production of innovative health solutions in contexts of vulnerability

    Acceptability of short message service (SMS) as a tool for malaria treatment adherence in the Brazilian Amazon: a qualitative study

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    Background: Malaria is one of the leading causes of morbidity worldwide, and patient adherence to prescribed antimalarials is essential for effective treatment. Methods: This cross-sectional study, with in-depth telephone interviews, analyzed participants’ perceptions of short message service (SMS) in adherence to treatment. Results: Five thematic categories emerged: decreased forgetfulness, the novelty of the tool, easy-to-understand language, the impact of SMS messages during treatment, and suggestions for improvement and complaints. Conclusions: SMS could assist patients in adhering to prescribed antimalarials.Fil: Rodovalho, Sheila. Universidade do Estado do Amazonas; BrasilFil: Dias, Ádila Liliane Barros. Universidade do Estado do Amazonas; BrasilFil: Paz Ade, Maria. Pan American Health Organization; ArgentinaFil: Saint Gerons, Diego Macias. Pan American Health Organization; ArgentinaFil: Castro, Jose Luis. Pan American Health Organization; ArgentinaFil: Beratarrechea, Andrea Gabriela. Instituto de Efectividad Clínica y Sanitaria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Murta, Felipe Leão Gomes. Universidade do Estado do Amazonas; BrasilFil: dos Santos, Alicia Cacau Patrine. Universidade do Estado do Amazonas; BrasilFil: Marques, Leonardo Lincoln Gomes. Universidade do Estado do Amazonas; BrasilFil: Sampaio, Vanderson Souza. Universidade do Estado do Amazonas; BrasilFil: Baia da Silva, Djane Clarys. Fundación Oswaldo Cruz; Brasil. Universidade do Estado do Amazonas; BrasilFil: Monteiro, Wuelton Marcelo. Universidade do Estado do Amazonas; Brasi

    The crude glycerin reduces losses fermentative and improves the nutritional value of marandu grass silage in a semiarid region / A glicerina bruta reduz perdas fermentativas e melhora o valor nutricional da silagem de capim marandu em uma região semiárida

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    The ensiling of marandu grass at the recommended time of management results in low dry matter (DM) content and nutritional value, but the addition of crude glycerin can compensate for these deficits if used during ensiling. Thus, the aim of this study was to evaluate the best level of inclusion of crude glycerin that can improve fermentation and the nutritional value of silages prepared with Urochloa brizantha cv. Marandu. The treatments consisted of five levels of inclusion of crude glycerin (0, 7.5, 15, 22.5, 30% of fresh forage) during ensiling of marandu grass with eight replications following the completely randomized design. For the evaluation of ruminal kinetics, four crossbred steers were used, cannulated in the rumen, following a randomized block design in a split plot scheme. For the percentage unit of inclusion of glycerin, there was a linear reduction of 0.34% in gas losses and increase of 0.45% and 0.55% in the recovery of DM (P <0.01) and in the DM content (P <0.01), respectively. The inclusion of up to 22.5% of crude glycerin in the silage of marandu grass is recommended to reduce losses during fermentation and improve the recovery of dry matter and the nutritional value of silage
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