O uso do software GeoGebra para o ensino de função do 2º grau: o caso da 1ª série do ensino médio de uma escola federal

No cenário atual da educação no Brasil, o ensino de Matemática não tem se mostrado eficiente nas escolas, tornado cada vez mais necessário buscar alternativas para melhorar esse quadro. Este trabalho surge a partir da dificuldade de se ensinar função no ensino médio do Instituto Federal da Bahia Campus Eunápolis, visto que, os alunos que ingressam na instituição apresentam deficiências em conteúdos que são pré-requisitos. Este cenário nos fez formular a seguinte pergunta: Como a utilização do software GeoGebra pode potencializar a exploração da função do 2o grau? Diante disto, este trabalho apresenta uma proposta de ensino da função quadrática com o auxílio do software GeoGebra a partir de uma sequência de atividades e ao final a construção de um mapa conceitual, que tinha como principal objetivo investigar como a utilização do software GeoGebra pode potencializar a exploração da função do 2o grau. A pesquisa, de abordagem qualitativa, ocorreu no Instituto federal da Bahia Campus Eunápolis em uma turma da 1a série do ensino médio com 36 alunos e teve duração de 10 aulas de 50 minutos, sendo que a cada duas aulas foi aplicada uma atividade de função quadrática. A análise dos dados seguiu a metodologia de descritiva, pois pretendia-se analisar as respostas dos alunos nas atividades. Os resultados mostraram que a utilização do software GeoGebra aliado às atividades contribuiu para a aprendizagem dos estudantes, pois a utilização do software permitiu maior manipulação e observação do objeto matemático (função do 2o grau) por parte dos alunos, precisão dos gráficos e a rapidez na sua construção otimizando o tempo de aula e permitindo assim discussões entre alunos e entre alunos e professor e exploração do comportamento da função em seus aspectos gráficos, contribuindo com a dedução de conceitos desta função de forma dinâmica e interativa.. Além disso, esta metodologia possibilitou que os estudantes tivessem uma postura ativa no processo de ensino e de aprendizagem, pois ao responder diretamente as questões, com o auxílio do software, o professor fazia apenas o papel de mediador.In the current scenario of education in Brazil, the teaching of mathematics has not been efficient in schools, that is why teachers and educators seek alternatives to reduce such inefficiency. The motivation to do this research arises from the difficulty I have to teach “function” to the first-year high school students who enter the Federal Institute of Bahia Campus Eunápolis since they present deficiencies in contents that are prerequisites to study other contents. This scenario has permitted us to ask the following question: How can I use GeoGebra software to enhance the exploration of the 2nddegree function? Thus, this work presents a proposal of teaching the quadratic function with the help of GeoGebra software from a sequence of activities and, at the end, doing a conceptual map, whose main objective is to investigate how the use of GeoGebra software can enhance the exploration of the 2 nd degree function. The qualitative research was carried out at the Federal Institute of Bahia Campus Eunápolis in a 1st high school class with 36 students and lasted 10 lessons of 50 minutes each, in whicha quadratic function activity was applied every two classes. The analysis of the data followed descriptive content analysis methodology, since it was intended to analyze the students' responses to the activities. The results haves howed that the use of the GeoGebra software added to regular activities have contributed to the students' learning, since the use of the software has allowed greater manipulation and observation of the mathematical object (2nd degree function) by the students, as well as the accuracy of the graphs and speed in its construction, optimizing the class time and allowing good discussions among students and between students and teacher. We could also explore the behavior of the function in its graphical aspects, contributing to the deduction of concepts of this function in a dynamic and interactive way. Moreover, such methodology made it possible that students could have an active posture in the teaching and learning process, since the teacher only played the role of mediator because the students were able to answer the questions, with the help of software

O Cabo-verdiano através dos olhos de forasteiros: representações nos textos portugueses, 1784-1844

Tese de mestrado, História de África, Universidade de Lisboa, Faculdade de Letras, 2011Ao ler os textos portugueses dos finais do século XVIII e a primeira metade do século XIX deparase com uma certa depreciação e africanização do homem cabo-verdiano. As formas de sociabilidade dos cabo-verdianos eram reprovadas por estes serem demasiados próximo dos “negros africanos”. Estas representações continuam a ser menos conhecidas tanto no domínio da História como nos outros campos do saber. Ora, o presente trabalho debruça-se sobre a imagem do homem caboverdiano construída, pensada, e dada a ler nos textos portugueses produzidos pelos forasteiros no período entre 1784 e 1844. O corpo textual que sustenta este estudo foi produzido a partir do contacto com as ilhas e os seus habitantes ou, muitas vezes, a partir de informações de terceiros, por alguém cujos padrões mentais e culturais pertenciam à outra realidade. Da longa relação dos portugueses/europeus com os africanos sob a soberania portuguesa no espaço cabo-verdiano desenvolveu-se uma cultura nova e um homem novo – uma nova sociedade, que por um lado reflecte o fracasso português na assimilação dos cabo-verdianos e por outro mostra a capacidade de, num espaço novo, através do processo de mestiçagem, que foi quase um fenómeno natural nas ilhas de Cabo Verde, surgir algo novo, com contornos próprios, que se pode caracterizar de caboverdianoAbstract: By reading late XVIII and first half of XIX centuries portuguese texts we find some depreciation and africanization of the Cape Verdean man. The forms of sociability of the Cape Verdeans were disapproved for being these very similar to the “black africans”. These representations are still not widely known in History and other areas of knowledge. So, the present dissertation focus on the image of the Cape Verdean man built, thought and readable in these Portuguese texts, produced by foreigners/outsiders in the period between 1784 and 1844. The accounts which sustain this study, the present dissertation was also built from contact with the Cape Verdean archipelago and its people, and sometimes counts with informations exchanged with persons which cultural and mental patterns fitting other realities. The long relationship between Portuguese/Europeans and Africans, under the portuguese sovereignty, in the Cape Verdean territory, gave birth to a new culture and a new man - a new society that expresses not only the Portuguese failure in the assimilation of the Cape Verdeans but also expresses the capacity to make something new happen. Something that, through the métissage process, in a new place, with its own aspects, can be named as Cape Verdean

Global optimal stabilization of MT-HVDC systems: Inverse optimal control approach

The stabilization problem of multi-terminal high-voltage direct current (MT-HVDC) systems feeding constant power loads is addressed in this paper using an inverse optimal control (IOC). A hierarchical control structure using a convex optimization model in the secondary control stage and the IOC in the primary control stage is proposed to determine the set of references that allows the stabilization of the network under load variations. The main advantage of the IOC is that this control method ensures the closed-loop stability of the whole MT-HVDC system using a control Lyapunov function to determine the optimal control law. Numerical results in a reduced version of the CIGRE MT-HVDC system show the effectiveness of the IOC to stabilize the system under large disturbance scenarios, such as short-circuit events and topology changes. All the simulations are carried out in the MATLAB/Simulink environment.Fil: Montoya Giraldo, Oscar Danilo. Universidad Tecnológica de Bolívar; Colombia. Universidad Distrital Francisco José de Caldas; ColombiaFil: Gil González, Walter. Institución Universitaria Pascual Bravo; ColombiaFil: Serra, Federico Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Investigaciones en Tecnología Química. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Investigaciones en Tecnología Química; Argentina. Universidad Nacional de San Luis. Facultad de Ingeniería y Ciencias Agropecuarias. Laboratorio de Control Automático; ArgentinaFil: de Angelo, Cristian Hernan. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados; ArgentinaFil: Hernández, Jesus C.. Universidad de Jaén; Españ

Whiteflies Provide Honeydew to Camponotus ants Without Receiving Reciprocal Favor

The notion that tending ants provide protection to honeydew-producing hemipterans is widely accepted. Nevertheless, there have been debates about whether or not this protection can always disrupt the biological control of hemipterans. Although various hemipteran species interact with tending ants, most studies have focused on the mutualism between ants and aphids.  Woolly whitefly Aleurothrixus floccosus (Maskell) is an important pest of citrus whose nymphs are frequently tended by ants such as Camponotus. However, it is unknown whether or not ants in this genus can disrupt biological control of woolly whitefly by protecting this pest’s nymphs from natural enemies. We investigated the impact of Camponotus ants on the biological control of woolly whitefly in the field by excluding or allowing the access of ants to whitefly nymph colonies in different tangerine trees. Furthermore, in a laboratory study we also assessed the behavior of Camponotus ants in response to woolly whitefly’s common predator cues (visual and scent).  In summary, this field-laboratory study suggests that there is no mutualism between tending Camponotus ants and the whitefly A. floccosus; rather it indicates commensalism as an alternative interaction. Interactions as this may provide more benefits for the host plant, whereby Camponotus ants can reduce sooty mold by removing honeydew from the leaves and favor pest biological control by leaving the whiteflies unprotected

Seasonality effect analysis and recognition of charging behaviors of electric vehicles: A data science approach

Electric vehicles (EVs) presence in the power grid can bring about pivotal concerns regarding their energy requirements. EVs charging behaviors can be affected by several aspects including socio-economics, psychological, seasonal among others. This work proposes a case study to analyze seasonal effects on charging patterns, using a public real-world based dataset that contains information from the aggregated load of the total charging stations of Boulder, Colorado. Our approach targets to forecast and recognize EVs demand considering seasonal factors. Principal component analysis (PCA) was used to provide a visual representation of the variables and their contribution and the correlation among them. Then, twelve classification models were trained and tested to discriminate among seasons the charging load of electric vehicles. Later, a benchmark stage is presented for regression as well as for classification results. For regression models, examined through Mean Absolute Percentage Error (MAPE) and Root Mean Square Error (RMSE), the random Forest provides better prediction than quasi-Poisson model widely. However, it was observed that for large variations in electric vehicles’ charging load, quasi-Poisson fits better than random forest. For the classification models, evaluated through Accuracy and the Area under the Curve, the Lasso and elastic-net regularized generalized linear (GLMNET) model provided the best global performance with accuracy up to 100% when evaluated on the test dataset. The results of this work offer great insights for enhancing demand response strategies that involve PEV charging regarding charging habits across seasons