Refletindo dificuldades de aprendizagem de alunos do ensino médio no estudo do equilíbrio químico

This research intends to identify the main conceptual mistakes committed by High School students when studying Chemical Equilibrium and also how the didactic books can influence in their formation. For the data - collecting we applied 150 questionnaires with 11 open questions e 4 restricted ones. Students from three different private schools in Natal-RN were used in this survey. The questionary about the book analysis tried to understand how the subject has been boarded, making it easier or not for the knowledge building. The books were chosen by being usually the most used ones at the chemistry classes in the schools in town. On the didactic book analysis we evaluated 12 items that tried to identify the clarity with which the books would bring up the subjects, the contextualization of the exercises, the analogies used, the amount and the quality of exercises, the connections between the subjects, and the retaken of important concepts. The questionary given to the students tried to get their knowledge about the concepts related to Chemical Equilibrium. The main mistakes found were: the definition of the state of equilibrium in a chemical reaction, the constant, the double headed arrow, confusions between mass and concentration, the representation of a microscopic reaction in equilibrium, partial pressure and total pressure, and the function of the catalyser. The results demonstrated a lot of insecurity or lack of knowledge about the subject when it was realized that there was a big number of blank questions and a considerable percentage of questions with conceptual errors. We concluded that those errors could be eased or even avoided if the didactic books and the teachers boarded the contents in a more conceptual form with the application of a largest number of good quality exercices, watching the building of definitions by the students, avoiding this way the formation of wrong concepts

Acurácia e precisão: revendo os conceitos de forma acurada

Accuracy concepts that involve systematic and random effects and precision, that involves only random ones, are reviewed in this paper. An objective discussion is presented based on the definitions that appear in the literature, followed by examples that may be enough to clarify some concepts and allow the extension for other applications. The discussion presented aims at raising eventual inconsistencies in the interpretations so as to provide better possibilities of use for those involved with this topic, which is fundamentally important in the quality analysis of cartographic, geodetic and remote sensing or photogrammetric products.

A escrita do texto acadêmico na graduação: modos de utilização de conceitos teóricos de uma área de conhecimento

In this study we have developed a discussion about academic text production in the undergraduate course of Literature and Languages. Specifically, we are going to analyze the monographic text writing in order to verify the meaning effects created from the ways of showing other s discourses that constitute a written production. As a means to do that, we are going to answer the following question: How does a young researcher make use of a theory in order to be part of a particular scientific community? We aim to: 1) analyze the linguistic resources, like quotations and signs of cohesion that demonstrate the other s voice presence in academic writing; 2) observe the meaning effects produced through the ways that the one who writes shows the other s voice in the written text. Firstly, we have selected 23 (twentythree) monographs produced in the last five years by students from a Literature and Languages undergraduate course in a determined public university. However, in this study, we have analyzed just 02 (two) different monographic texts. To develop such an investigation, we have inquired Kuhn s concept of science, which shows the existence of different meanings of science production in the course of the centuries. It allows us to define academic writing as science production that develops and contributes to knowledge production. With the purpose of restricting the meaning of writing conception, we have relied on Coracini, who assumes that all writing production is the registration of the self, in other words, writing comes from the subject s intervention, it is to say that only an imposition of the self guarantees the subject as author of what he writes. We have as theoretical basis the following concepts: 1-) Authier-Revus s enunciative heterogeneity, that allowed us to analyze the written marks of the other in the monographic writing; 2-) Pêcheux s reformulation-paraphrase and Orlandi s polysemy and paraphrase, concepts that present notions of productivity and creativity as ways of meaning production, and allows us to observe how the process of language production in academic writing is established; 3-) Rossi-Landi s concept of exchange-value and use-value, which consider language as a linguistic work, allowing us to verify the differences between use and social functionality in a determined theory; and 4-) Possenti s notion of authorship indicia, with which we have identified attitudes that make the one who writes author of his own text. We have verified that writing characterized for repetition and reproduction may develop a meaning effect that constructs the idea that writing production promotes an author, a concept or a theory. We have also realized that a written text that restricts itself to reproduce other authors discourses and does not articulate a theory with data analysis or with work methodology, when evaluated is approved and legitimates itself as scientific production. That demonstrates the existence of academic productions that do not develop any functionality of the employed theory. The text works as a means to promote its theoretical concepts, and theory. It is to say that the theoretical foundantion, which usually is a way to argue and sustain scientific production, does not have any function. Thus, we consider that the way someone shows the other s discourse in academic writing may work as a way to underline what the other asserts to the detriment of the researcher s words. This fact allows us to comprehend that a way of writing may evidence a meaning effect of the author s, theory s or theoretical concepts promotion

Caracterização química de glucanas fúngicas e suas aplicações biotecnológicas

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Modalização autonímica: um estudo de utilização e apropriação do discurso sobre os conceitos de variação e de mudança na escrita de dissertação de mestrado de 1970 - 2011

Universidade Federal do Rio Grande do Norte

Deus, mente e mundo: sobre os conceitos de complicatio, imago e explicatio a partir do diálogo de mente de nicolau de cusa

This work deals with the way how the three themes of traditional metaphysics, namely, God, man, and the world, are rethought through the philosophical speculation of German cardinal Nicholas of Cusa (1401-1464). Due to the comprehensiveness of this subject, our dissertation had as a starting point and constant reference the book that the philosopher wrote in 1450, Idiota. De mente, the second written work that makes up the series of the Idiota (Idiotae libri), whose discussion is developed around the theme of the human mind. From the dialogue of the mind we have built our reflection on some issues and theoretical foundations presented in Idiota. De sapientia and De docta ignorantia, extending it to little more than that. According to Nicholas of Cusa, the human mind, in its creative character in the image of the divine mind, transcends the purely functional considerations commonly assigned to it, that is, those that regard its cognitive nature and epistemological role. In addition to these aspects, Cusanus understands the humana mens as a point of articulation of two other main themes of his metaphysics: God and the world. In this context, through the concepts of complicatioexplicatio and imago, as well as with the intercession between the themes of man as imago Dei and the reason of the microcosm, we present here an introduction to Cusan metaphysics

Os Polímeros como Sistemas Complexos

Neste trabalho, através de simulações computacionais, identificamos os fenômenos físicos associados ao crescimento e a dinâmica de polímeros como sistemas complexos exibindo comportamentos não linearidades, caos, criticalidade auto-organizada, entre outros. No primeiro capítulo, iniciamos com uma breve introdução onde descrevemos alguns conceitos básicos importantes ao entendimento do nosso trabalho. O capítulo 2 consiste na descrição do nosso estudo da distribuição de segmentos num polímero ramificado. Baseado em cálculos semelhantes aos usados em cadeias poliméricas lineares, utilizamos o modelo de crescimento para polímeros ramificados (Branched Polymer Growth Model - BPGM) proposto por Lucena et al., e analisamos a distribuição de probabilidade dos monômeros num polímero ramificado em 2 dimensões, até então desconhecida. No capítulo seguinte estudamos a classe de universalidade dos polímeros ramificados gerados pelo BPGM. Utilizando simulações computacionais em 3 dimensões do modelo proposto por Lucena et al., calculamos algumas dimensões críticas (dimensões fractal, mínima e química) para tentar elucidar a questão da classe de universalidade. Ainda neste Capítulo, descrevemos um novo modelo para a simulação de polímeros ramificados que foi por nós desenvolvido de modo a poupar esforço computacional. Em seguida, no capítulo 4 estudamos o comportamento caótico do crescimento de polímeros gerados pelo BPGM. Partimos de polímeros criticamente organizados e utilizamos uma técnica muito semelhante aquela usada em transições de fase em Modelos de Ising para estudar propagação de danos chamada de Distância de Hamming. Vimos que a distância de Hamming para o caso dos polímeros ramificados se comporta como uma lei de potência, indicando um caráter não-extensivo na dinâmica de crescimento. No Capítulo 5 analisamos o movimento molecular de cadeias poliméricas na presença de obstáculos e de gradientes de potenciais. Usamos um modelo generalizado de reptação para estudar a difusão de polímeros lineares em meios desordenados. Investigamos a evolução temporal destas cadeias em redes quadradas e medimos os tempos característicos de transporte t. Finalizamos esta dissertação com um capítulo contendo a conclusão geral denoss o trabalho (Capítulo 6), mais dois apêndices (Apêndices A e B) contendo a fenomenologia básica para alguns conceitos que utilizaremos ao longo desta tese (Fractais e Percolação respectivamente) e um terceiro e ´ultimo apêndice (Apêndice C) contendo uma descrição de um programa de computador para simular o crescimentos de polímeros ramificados em uma rede quadrada

Determinação do perfil dos usuários e da composição química e nutricional da alimentação oferecida no restaurante universitário da Universidade Estadual Paulista, Araraquara, Brasil

Este estudo teve como objetivos determinar o perfil e o estado nutricional da clientela e a composição química e nutricional das refeições oferecidas no restaurante universitário da Universidade Estadual Paulista de Araraquara, Brasil. Realizou-se a determinação química do teor de proteínas, lipídios, carboidratos, fibra, cinzas e umidade de amostras das refeições fornecidas. A amostra populacional foi constituída de 403 usuários (212 mulheres e 191 homens). em relação ao perfil do usuário, constatou-se que 82,60% encontravam-se na faixa etária de 18 a 25 anos e 75,44% dos indivíduos apresentaram índice de massa corporal dentro da faixa de normalidade. em média, as refeições continham 4,74% de proteínas, 10,84% de lipídeos, 24,32% de carboidratos, 3,30% de fibras, 1,00% de cinzas e 55,00% de umidade. Os dados mostraram que as refeições do restaurante universitário continham excesso de proteínas e de energia e que se faz necessário realizar ajustes na sua composição para adequá-la ao perfil da clientela atendida.

Conceitos e técnicas da mecânica estatística e termodinâmica aplicados ao estudo dos grafos aleatórios

This dissertation briefly presents the random graphs and the main quantities calculated from them. At the same time, basic thermodynamics quantities such as energy and temperature are associated with some of their characteristics. Approaches commonly used in Statistical Mechanics are employed and rules that describe a time evolution for the graphs are proposed in order to study their ergodicity and a possible thermal equilibrium between them

Construção de Conceitos Matemáticos na Educação Básica numa Abordagem Peirceana

Peircean semiotic analysis is employed to examine the construction/representation of signs-thinking of 32 early elementary school students regarding the concept of length measurement. The work consisted of developing concepts of standard unit, reading and interpretation of measurement by instruments, so that the mathematical language presented in the concrete materials was being signified and re-signified as a tool for perception and representation of new concepts. The pedagogical triad Feeling-Perceiving, Relating-Concept (F-P/R/C) co-related with the dynamism of the semiosis process, defined by Charles Sanders Peirce (1839-1914) in his semiotic theory on the production of the sign (Object, Representamen and Interpretant), enabled the interpretation and analysis of the students' inferences in the phase of perception (feel, admire), induction (experience), and deduction (concept).

Conceitos de didática: depoimentos de docentes universitários da área de Educação Física

Na pesquisa investigou-se como docentes universitários em Educação Física conceituam didática. Realizou-se revisão da literatura abordando história e conceituações da didática. Utilizando-se a técnica de entrevista e análise qualitativa, coletou-se e analisou-se depoimentos de treze docentes universitários oriundos do mestrado em Educação Física. Com o método de abordagem histórico constatou-se que a didática esteve articulada às tendências pedagógicas: tradicional, escola nova, tecnicista e progressista e é conceituada como disciplina, área de estudos e técnica de ensino. Como técnica pode ser entendida no sentido amplo, referindo-se a procedimentos de levar alguém a aprender algo e no sentido pedagógico apresenta os procedimentos atrelados à questões sócio-morais. Os depoimentos coletados revelaram que os docentes universitários entendem a didática no sentido amplo. Conclui-se que na formação destes docentes universitários a didática foi abordada apenas como técnica de ensino, apesar de sua trajetória histórica e a prática pedagógica estarem diretamente ligadas aos rumos da educação.

Os conceitos de eletricidade vítrea e eletricidade resinosa segundo Du Fay

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Influência da composição química do substrato no cultivo de Pleurotus florida

Com o objetivo de avaliar a influência da composição química do substrato no cultivo do cogumelo comestível Pleurotus florida, seis resíduos agrícolas foram testados: palha de arroz, palha de feijão, palha de trigo, folha de bananeira, palha de sorgo e sabugo de milho. O substrato palha de feijão apresentou resultados semelhantes para a produção (189,8 g kg-1), eficiência biológica (89,2%) e número de cogumelos (12) à palha de arroz, substrato utilizado tradicionalmente no cultivo de Pleurotus em escala comercial. Não foi possível atribuir apenas a um fator químico as altas produções e eficiências biológicas observadas em palha de arroz e palha de feijão e muito menos para a baixa produção em palha de sorgo (77,8 g kg-1) e sabugo de milho (53,2 g g-1). No geral, substratos com relação C/N em torno de 45 (N = 1,0%), maior conteúdo de cinzas, acrescido de altos teores de P, K, Ca, Mg and Mn foram os melhores para o cultivo de P. florida.

Dependência química em mulheres :um estudo sobre o consumo de medicamentos ansiolíticos no serviço público de saúde de Natal/RN

This work was concerned to investigate the meaning attributed to anxiolytic drugs by women, in public health service. It proposes a joint analysis through a link between three dimensions: the woman, the drug, and public health service itself, in an hegemonic medical assistance model. It is observed that the relation between these elements has a great influence over the use and construction of a particular meaning, by the user. The medication is analysed as a consumption merchandise and as an health symbol. In this way, it reflects a biologized vision, which believes the drug as a solution for all health problems. It tries to analyse the generalized medical prescription for anxiolythics and it s consequences. It focalizes also the production and utilization of public health services by patients, mainly women. The question related to the use of anxiolytics and the meaning construted by women is analysed focusing the way that relations of masculine/feminine gender are organized in our society. At this point of view, it tries to understand the dimension that these questions have in subjectivity production, and how it acts in the health/disease process. Finally, this work tries to understand, in a broad sense, the use of anxiolytics looking at the problem not only as a biological question, but also as a cultural matter. The research was done over seventeen women, all of them anxiolytic users. It was used, as research instrument, semi-structured interview associated with methodological analysis of user s speeches

Avaliação das condições química e física dos sedimentos do estuário Jundiaí-Potengi

The aim of this study was to quantify the presence of major and minor elements in the sediments of the Jundiaí-Potengi estuary, bordering the municipalities of Macaíba, Natal and São Gonçalo do Amarante in the state of Rio Grande do Norte, Brazil, considering the evidence of anthropic activity along this estuary, resulting in pollution by treated and untreated wastewaters as well as those produced by industry and shrimp farming. The assessment of the environmental status of this estuary was based on physical-chemical parameters, such as granulometry, organic matter and the major (Al, Fe, Mn and P) and minor (Cd, Cr, Cu, Ni, Pb and Zn) elements found in sediment samples. Two collections were made at 12 georeferenced points along the channel of the estuary at different times. Granulometric analysis was carried out and the percentage of organic matter was determined. The sediments were microwave digested using acid digestion and quantitative analyses of the elements Al, Fe, Cd, Cr, Cu, Mn, Ni, P, Pb and Zn were performed by inductively coupled plasma optical emission spectrometry. Sediment analysis followed the methodology proposed by US EPA 3051A for total elements analysis. The small correlation between the organic matter and the elements studied here suggests that they are of geochemical rather than anthropic origin. The analytical results obtained from the bottom sediment samples in the study area show that the concentration of elements was below the reference values for standard shales (Turekian & Wedepohl, 1961) at the vast majority of points analyzed, ruling out a possible contamination by metals