Os gêneros de discurso do texto de biologia dos livros didáticos de ciências

Este trabalho analisa o texto de biologia do livro didático de ciências. A hipótese principal é que esse texto constitui-se em um gênero  de discurso distinto, construído a partir de elementos dos gêneros de discurso científico, didático e cotidiano. Para estudar essa hipótese, buscamos apoio nas concepções de Bakhtin (1953/1997) sobre gêneros de discurso e linguagem social e usamos um conjunto de categorias para caracterizar esses diferentes gêneros de discurso. Essas categorias foram construídas a partir das tipologias textuais de Bronckart (1999) baseadas nas ordens do ‘narrar’ e do ‘expor’; da estrutura analítica utilizada Mortimer e Scott (2002, 2003) para analisar o discurso de sala de aula de ciências; e de alguns elementos gramaticais identificados por Halliday e Martin (1993) nos textos científicos e didáticos. Tendo por base a análise de coleções didáticas de Ciências, do segmento de 5a a 8a série, recomendadas pelo Programa Nacional do Livro Didático  – PNLD/1999 e PNLD/2002, do Ministério de Educação – MEC, foram selecionadas duas coleções, ambas recomendadas nas avaliações do PNLD em 1999 e em 2002 e escolhidas por um número expressivo de professores da rede pública nos dois PNLDs. Foram analisados dois capítulos diferentes dessas coleções, que contemplam temas biológicos distintos – metabolismo e diversidade dos seres vivos. Num primeiro momento, as categorias são explicitadas e exemplificadas por trechos extraídos desses capítulos. A seguir, todos os períodos que constituem os textos desses diferentes capítulos são analisados segundo essas categorias, o que permitiu verificar nossa hipótese de trabalho e fazer inferências sobre a articulação entre os gêneros nos diferentes conteúdos abordados e sobre as particularidades de cada coleção

Conceptual Profiles: Theoretical-methodological Grounds and Empirical Studies

AbstractIn this paper, we briefly address the theoretical and methodological grounds of the conceptual profile theory and discuss two empirical studies aiming at constructing conceptual profile models and using them to analyze classroom discourse in different sciences, chemistry (entropy and spontaneity) and biology (adaptation). The basic idea is to illustrate how these models were built, considering differences and similarities between the methods used for this purpose. Conceptual profiles are models of different modes of seeing and conceptualizing the world used by individuals to signify their experience. They are built for a given concept and are constituted by several zones, each representing a particular mode of thinking about that concept, related to a particular way of speaking. Each zone is individuated by ontological, epistemological, and axiological commitments underlying discourse. We will show how different concepts, situated in sciences with different levels of conceptual polysemy, demand different methodologies to deal with the variation found in meaning making in the sociocultural, ontogenetic, and microgenetic domains

Perfis conceituais de entropia e espontaneidade de processos físicos e químicos: uma abordagem voltada para a sala de aula

L’article té com a objectiu presentar diferents maneres de pensar i parlar sobre l’espontaneïtat dels processos físics i químics i l’entropia, estructurades en zones d’un perfil conceptual basat en situacions i fenòmens que els docents poden discutir a l’aula. La discussió sobre l’heterogeneïtat de pensament i llenguatge d’aquests dos conceptes serà utilitzada com a suport per a la proposició d’aspectes epistemològics, pedagògics i didàctics que puguin possibilitar un abordatge contextualitzat i plural del concepte d’entropia i d’espontaneïtat dels processos físics i químics, buscant facilitar l’acció docent a les classes de química.The article aims to present different ways of thinking and talking about spontaneity of physical and chemical processes and entropy, structured in zones of a conceptual profile, based on situations and phenomena that can be discussed by teachers in the classroom. The discussion about the heterogeneity of thought and language of these two concepts will be used as support for the proposition of epistemological and pedagogical resources that can enable a contextualized and plural approach to the concept of entropy and spontaneity of physical and chemical processes, seeking facilitate the teaching action in chemistry classes.O artigo tem por objetivo apresentar diferentes modos de pensar e falar sobre espontaneidade de processos físicos e químicos e entropia, estruturados em zonas de um perfil conceitual, a partir de situações e fenômenos que podem ser discutidos por professores em sala de aula. A discussão sobre a heterogeneidade do pensamento e da linguagem desses dois conceitos será usada como suporte para a proposição de recursos epistemológicos, pedagógicos e didáticos que podem possibilitar uma abordagem contextualizada e plural para o conceito de entropia e de espontaneidade dos processos físicos e químicos, buscando facilitar a ação docente em aulas de química

Ten millennia of hepatitis B virus evolution

Hepatitis B virus (HBV) has been infecting humans for millennia and remains a global health problem, but its past diversity and dispersal routes are largely unknown. We generated HBV genomic data from 137 Eurasians and Native Americans dated between ~10,500 and ~400 years ago. We date the most recent common ancestor of all HBV lineages to between ~20,000 and 12,000 years ago, with the virus present in European and South American hunter-gatherers during the early Holocene. After the European Neolithic transition, Mesolithic HBV strains were replaced by a lineage likely disseminated by early farmers that prevailed throughout western Eurasia for ~4000 years, declining around the end of the 2nd millennium BCE. The only remnant of this prehistoric HBV diversity is the rare genotype G, which appears to have reemerged during the HIV pandemic

Symposium 1: Investigating Teaching Practices that Promote Learning in Science Lessons

In this talk we use the notion of communicative approach, as outlined in our book (Mortimer & Scott 2003), as a way of highlighting the science teaching practices carried out by two teachers, one Brazilian and the other British. The characteristics that emerge from these practices demonstrate that teaching for meaningful learning involves progressive shifting between authoritative and dialogic communicative approaches. On the one hand, dialogic discourse is open to different points of view. The discourse direction changes as ideas are introduced and explored and the teachers assume a neutral position, avoiding evaluative comments and encouraging and probing student ideas. On the other hand, authoritative discourse focuses on a single perspective, normally the school science view. The discourse direction is prescribed in advance and the authority of teacher is clear:  he/she acts as a gatekeeper to points of view, through reshaping, ignoring, rejecting student ideas. The relationship between dialogic and authoritative approaches is that dialogic exploration of both everyday and scientific views requires resolution through authoritative guidance by the teacher. In shifting between dialogic and authoritative discourses these two teachers shows a number of pedagogical skills: they sustain a line of speech and thought, through which ideas are introduced, reviewed and consolidated in a cumulative process involving the creation of temporal links. They also monitor and follow the students’ understanding. They sistematicaly progress from the phenomenon to the description and explanation. And they select carefully developed activities to ensure the advancement of the scientific story. They also show affective and emotional skills, systematically encouraging the participation of all members of the class,offering approval, modeling the enthusiasm, recalling individual ideas and arguments of the students and linking to their names, and being consistent, warm and having control.With our analytical framework we are able to highlight all these features and to get a more precise idea of what are good teaching practices.Mortimer, E.F. & Scott, P. (2003) Meaning Making in Secondary Science Classroom. Maidenhead: Open University Press

Promoting awareness of conflicts: analysis of discursive activity in science classroom

This paper will examine how the conflict between the scientific point of view and the students’ everyday point of view can be perceived and overcome by the students with the mediation of a teacher. For this purpose we analyze a science class episode, which was recorded when a teaching sequence on heat and temperature was carried out with students aged 14-15 in a Brazilian secondary school. We used the framework proposed by Mortimer and Scott (2002, 2003) to make visible discursive moves that allows the students to become aware of the conflict between two models they use, in different circumstances, to interpret thermal phenomena: the kinetic particle model and a model of heat and cold exchange. Our analysis demonstrates how the teacher’s interventions guided the students to examine their own ideas through a slow and laborious meaning making process. We were able to identify changes in the teacher’s purposes and type of interventions as the students further developed their ideas. These changes are associated to alternations in the communicative approaches, first dialogic and then mainly authoritative. As in Mortimer and Machado (2000), our data indicate that the process of becoming aware of and overcoming conflicts, in the classroom, depends not only on the choice of suitable teaching strategies, but above all, on the discourse teacher and students build around the experiment

Bases teóricas e epistemológicas da abordagem dos perfis conceituais

Neste artigo, discutimos bases teóricas e epistemológicas da abordagem dos perfis conceituais, concebida como uma maneira de modelar a heterogeneidade do pensamento e da linguagem em salas de aula de ciências. Nós distinguimos entre duas visões sobre conceitos: (1) conceitos como modelos ou esquemas mentais de objetos ou eventos; (2) conceitos como exibindo significados relativamente estáveis e existindo apenas nas linguagens naturais e nos sistemas de conhecimento, e diferenciando-se da conceitualização, um processo dinâmico que ocorre nas mentes dos indivíduos, como resultado de interações socialmente situadas com eventos e experiências externas. Nós discutimos a aprendizagem da perspectiva da abordagem dos perfis conceituais, tratando-se como envolvendo os processos relacionados de enriquecimento de perfis conceituais e tomada de consciência tanto da heterogeneidade quanto da demarcação de modos de pensar e falar. Por fim, discutimos se a abordagem dos perfis conceituais é relativista, defendendo que ela é, antes, uma abordagem pragmatista objetiva