O ensino da química na perspectiva da literacia química: recursos didácticos para o ensino básico

Defende-se hoje que o Ensino Básico deve, acima de tudo, dotar os alunos de competências que lhes permitam interagir com a sociedade em que se inserem, o que legitima as expectativas no sentido da formação de cidadãos capacitados para exercer a sua responsabilidade social. O processo de Reorganização Curricular do Ensino Básico actualmente em curso, em Portugal, segue esta orientação e propõe um ensino das ciências no sentido da formação dos alunos para a literacia científica. Ora, neste contexto o movimento CTS (Ciência-Tecnologia-Sociedade) assume-se como uma filosofia de ensino que muito se coaduna com os fins pretendidos. Para tal, é importante ter recursos didácticos consonantes com esta perspectiva, que suportem as práticas dos professores. O presente estudo teve por objectivo conceber e validar recursos didácticos CTS utilizáveis por professores e alunos, no âmbito do ensino e da aprendizagem do tema Sustentabilidade na Terra, no 3º ciclo do Ensino Básico. O percurso metodológico seguido incluiu várias etapas de entre as quais se destacam pela sua importância: a selecção de um contexto viável para a abordagem do tema Sustentabilidade na Terra; a planificação da abordagem CTS do referido tema; a formulação de questões-problema centradas nos domínios científico, social e tecnológico; a definição dos objectivos CTS na abordagem do problema em causa; a organização de estratégias de exploração das questões problema; a validação dos Recursos Didácticos por professores de Química qualificados e experientes. Optou-se, de uma forma fundamentada, pelo contexto geral “Barragem de Alqueva”. O produto final do presente estudo apresenta-se na forma de um Caderno de Recursos Didácticos CTS constituído por catorze actividades, organizado em Notas para o Professor, Tarefas para o Aluno e Resposta Adequada, concebidas para o contexto geral Barragem de Alqueva, e estruturadas em torno de quatro sub-temas orientadores: Água, Energia, Materiais e Resíduos. Com vista à validação dos Recursos Didácticos construídos planificou-se e realizou-se o Workshop “Sustentabilidade na Terra – perspectivas didácticas para a sua abordagem” que foi dinamizado pela autora e dirigido a um painel de treze Professores Avaliadores e no qual participaram também, como Avaliadoras Externas, duas professoras especialistas em formação de professores. VII O processo de validação evidenciou que na opinião dos avaliadores: o contexto Barragem de Alqueva é de grande relevância social e adequado à abordagem da temática Sustentabilidade na Terra; os recursos didácticos são adequados quanto ao interesse e extensão dos textos inseridos nas problemáticas desenvolvidas, quanto à adequabilidade da linguagem à faixa etária a que se destinam, quanto ao grau de profundidade dos objectos de ensino, favorecem o desenvolvimento de uma atitude crítica, favorecem o desenvolvimento de uma atitude investigativa, de recolha de dados e busca de informação complementar, contribuem para o desenvolvimento de atitudes de preservação do ambiente e contribuem para a compreensão do tema Sustentabilidade na Terra; as questões que constituem as Tarefas para o Aluno são, em geral, exequíveis pelos alunos a que se destinam. O processo de validação foi considerado quer pelos Professores Avaliadores, quer pelas Avaliadoras Externas, adequado aos objectivos do Workshop e, de um modo geral, muito importante na formulação de uma opinião sobre os Recursos Didácticos. As Avaliadoras Externas consideraram-no válido e fiável o que legitima as conclusões dele decorrentes. Deste modo, pode dizer-se que o contributo do presente estudo para a inovação no ensino da Química se reflecte no Caderno de Recursos Didácticos construído bem como na explicitação de uma metodologia útil para investigadores e professores interessados na concepção e construção de recursos CTS.

Aprendizagem das ciências em espaços não-formais: visita de estudo na rota das energias renováveis

Nos programas actuais defende-se um ensino contextualizado numa perspectiva CTSA - Ciência, Tecnologia, Sociedade e Ambiente, e a diversificação de estratégias e actividades é recomendada. Numa perspectiva construtivista, a aprendizagem fora da sala de aula, aprendizagem em espaços não-formais - as visitas de estudo - são consideradas como uma das estratégias com elevado potencial pedagógico. No presente estudo foram realizadas e avaliadas duas visitas de estudo no âmbito da disciplina de Física e Química do 10° ano de escolaridade, tendo a primeira sido feita como estudo-piloto ao Centro de Ciência Viva de Constância e uma segunda como estudo principal, Na Rota das Energias Renováveis, à Barragem do Alqueva, Central Solar Fotovoltaica da Amareleja, Parque de Natureza de Noudar e Herdade do Esporão. Realizou-se uma pré-visita aos locais a visitar, estabeleceram-se contactos privilegiados com as instituições visitadas, preparam-se materiais didácticos, um Roteiro e um Guia de Campo para cada local visitado, foram elaborados e apresentados aos alunos questionários sobre o seu grau de satisfação com as visitas e realizaram-se ainda entrevistas em grupo com alguns alunos para recolher as suas impressões. Os alunos realizaram trabalhos de divulgação da visita tendo sido disponibilizada, no "site" da escola, informação detalhada sobre a visita. Neste estudo analisou-se em que medida uma aprendizagem contextualizada num espaço não-formal foi promotora de um envolvimento produtivo dos alunos. As aprendizagens realizadas situaram-se no domínio cognitivo, social ou atitudinal e os materiais didácticos, como o Guia de Campo tiveram um papel relevante para essas aprendizagens. A motivação dos alunos para a disciplina melhorou durante e após a visita. A colaboração com as instituições visitadas mostrou-se importante no estabelecimento de uma interface entre o espaço formal e o não-formal. A realização de visitas de estudo é uma componente importante dos curricula e deve ser encarada com naturalidade a sua realização frequente, como parte de uma estratégia para motivar os alunos para a disciplina e aumentar a sua capacidade de aprender os conteúdos. ABSTRACT: Nowadays programs defend teaching model that follows a perspective based in Science, Technology, Society and Environment, with special focus in the diversification of strategies. Outside of classroom teaching, in non-formal spaces, as in field trips, is considered one of the strategies with the highest pedagogic potential. ln this study, two field trips were made based on the Physics and Chemistry program for the 1Oth grade, with the first one as the pilot visit to Centro de Ciência Viva de Constância, and the second one as the main study, ln the Path of Renewable Energies, to Alqueva’s dam, Amareleja's Solar Photovoltaic Center, Noudar's Nature Park and Herdade do Esporão. A pre-visit was made for each one of the places to visit, contacts were made, materials were created, an itinerary and a Field Guide for both field trips, satisfaction questionaries were made to the students and the teacher also interviewed some students for appreciations about the visit. The students created posters about the field trip, and information was also showed in the school website. With this study, the benefits of a contextualized learning in a non-formal space were demonstrated. These acquisitions of knowledge were in various domains, such as cognition, social behavior and the didactic materials had a relevant role in these acquirements. Moreover, the students' motivation for the subject in question improved significantly during and after the field trip. The cooperation with the visited institutions revealed to be important in the establishment of an interface between the formal and the non-formal spaces. Making field trips is an important component in the curricula and should be encouraged and seen as a natural part of a strategy of motivation of the students for a certain subject, increasing its ability to learn matters.

Articulação Centro de Pesquisa: Escola Básica: contribuições para a alfabetização científica e tecnológica

Neste artigo são discutidos aspectos relacionados à seleção e organização dos conteúdos a serem abordados durante e após visitas a laboratórios de pesquisa em física. Utilizando como exemplo o trabalho de divulgação realizado no acelerador de partículas Pelletron (Instituto de Física da Universidade de São Paulo), com alunos do ensino médio, procuramos identificar elementos que podem orientar o desenvolvimento de propostas escolares organizadas a partir de visitas a centros de pesquisa. Nesse sentido, destaca-se o potencial dessas visitas para a realização de discussões sobre as relações entre Ciência-Tecnologia-Sociedade e a importância do estabelecimento de vínculos com o conteúdo escolar

HR Del REMNANT ANATOMY USING TWO-DIMENSIONAL SPECTRAL DATA AND THREE-DIMENSIONAL PHOTOIONIZATION SHELL MODELS

The HR Del nova remnant was observed with the IFU-GMOS at Gemini North. The spatially resolved spectral data cube was used in the kinematic, morphological, and abundance analysis of the ejecta. The line maps show a very clumpy shell with two main symmetric structures. The first one is the outer part of the shell seen in H alpha, which forms two rings projected in the sky plane. These ring structures correspond to a closed hourglass shape, first proposed by Harman & O'Brien. The equatorial emission enhancement is caused by the superimposed hourglass structures in the line of sight. The second structure seen only in the [O III] and [N II] maps is located along the polar directions inside the hourglass structure. Abundance gradients between the polar caps and equatorial region were not found. However, the outer part of the shell seems to be less abundant in oxygen and nitrogen than the inner regions. Detailed 2.5-dimensional photoionization modeling of the three-dimensional shell was performed using the mass distribution inferred from the observations and the presence of mass clumps. The resulting model grids are used to constrain the physical properties of the shell as well as the central ionizing source. A sequence of three-dimensional clumpy models including a disk-shaped ionization source is able to reproduce the ionization gradients between polar and equatorial regions of the shell. Differences between shell axial ratios in different lines can also be explained by aspherical illumination. A total shell mass of 9 x 10(-4) M(circle dot) is derived from these models. We estimate that 50%-70% of the shell mass is contained in neutral clumps with density contrast up to a factor of 30.

Influence of egg pre-storage heating period and storage length on incubation results

This experiment aimed at evaluating the influence of different heating times of settable eggs of Cobb 500 (R) broiler breeders before submitting them to different storage periods on egg weight loss, embryo mortality, and hatchability. A total number of 1,980 eggs were distributed in a completely randomized experimental design with a 3 x 3 factorial arrangement, comprising nine treatments with 22 replicates of 10 eggs each. The following factors were analyzed: pre-storage heating periods (0, 6, 12 hours at 36.92 degrees C) and storage periods (4, 9, 14 days at 12.06 degrees C). After storage, eggs were incubated under usual conditions, and were transferred to the hatcher at 442 hours of incubation. Eggs were weighed before heating, incubation, and transference to determine weight loss. Partial hatchability was determined at 480 hours, and total hatchability at 498 hours of incubation. Embryo mortality was determined in non-hatched eggs. It was concluded that heating eggs for six hour before storage improves incubation results as it decreases incubation length and late embryo mortality, therefore its use can be indicated in commercial operations. Storing eggs for 14 days and pre-heating for 14 days and pre-heating for 12 hours severely impair incubation results, and therefore are not recommended.

Influence of egg pre-storage heating period and storage length on the digestive tract of newly-hatched broiler chicks

An experiment was carried out to evaluate the effect of different heating times of settable eggs of Cobb 500 (R) broiler breeders before submitting them to different storage periods on body weight, digestive tract organ weights, and intestinal mucosa morphology of newly-hatched chicks. Settable eggs were distributed in a completely randomized experimental design with a 3 x 3 factorial arrangement: pre-storage heating periods (0, 6, 12 hours at 36.92 degrees C) and storage periods (4, 9, 14 days at 12.06 degrees C). Body weight and relative weights of the yolk sac, heart, liver, proventriculus+gizzard, and intestinal segments were measured in chicks hatching at 480 and 498 hours of incubation. Villi height, width and perimeter, and crypt depth < im) were measured in duodenal histological sections. It was concluded that pre-storage healing for six hours of eggs stored for four or nine days increases small intestine weight of newly-hatched chicks, but does not influence the morphology of the duodenal mucosa. Pre-storage heating for 12 hours negatively influences body weight and duodenal mucosa development, and therefore this practice is not recommended. Storage length does not have consistent effect on body weight and development of the gastrointestinal tract.

Foundation and Perspectives of the Use of Plant Extracts as Performance Enhancers in Broilers

Feed is responsible for about 70% of broilers production costs, leading to an increasing number of studies on alternative dietary products that benefit bird performance and lower production costs. Since the 1950s, antimicrobial additives are the most frequently used performance enhancers in animal production and their positive results are observed even in high-challenge conditions. Since the 1990s, due to the ban of the use of some antibiotics as growth promoters and the growing trend of the public to consume natural products, plant extracts have been researched as alternatives to antibiotic growth promoters. The first study that evaluated the antibacterial activities of plant extracts was carried out in 1881; however, they started to be used as flavor enhancers only during the next decades. With the emergence of antibiotics in the 1950s, the use of plant extracts as antimicrobial agents almost disappeared. There are several studies in literature assessing the use of plant extracts, individually or in combination, as antimicrobials, antioxidants, or digestibility enhancers in animal feeds. Research results on the factors affecting their action, such as plant variety, harvest time, processing, extraction, as well as the technology employed to manufacture the commercial product and dietary inclusion levels show controversial results, warranting the need of further research and standardization for the effective use of plant extracts as performance enhancers, when added to animal feeds. This article aims at presenting plant extracts as alternatives to antibiotics, explaining their main modes of action as performance enhancers in broiler production.

Brown spider venom toxins interact with cell surface and are endocytosed by rabbit endothelial cells

Bites from the Loxosceles genus (brown spiders) cause severe clinical symptoms, Including dermonecrotic injury, hemorrhage, hemolysis, platelet aggregation and renal failure. Histological findings of dermonecrotic lesions in animals exposed to Loxosceles intermedia venom show numerous vascular alterations Study of the hemorrhagic consequences of the venom in endothelial cells has demonstrated that the degeneration of blood vessels results not only from degradation of the extracellular matrix molecule or massive leukocyte infiltration, but also from a direct and primary activity of the venom on endothelial cells. Exposure of an endothelial cell line in vitro to L. intermedia venom induce morphological alterations, such as cell retraction and disadhesion to the extracellular matrix. The aim of the present study was to investigate the interaction between the venom toxins and the endothelial cell surface and their possible internalization, in order to illuminate the information about the deleterious effect triggered by venom After treating endothelial cells with venom toxins, we observed that the venom Interacts with cell surface. Venom treatment also can cause a reduction of cell surface glycoconjugates When cells were permeabilized, it was possible to verify that some venom toxins were internalized by the endothelial cells The venom internalization involves endocytic vesicles and the venom was detected in the lysosomes. However, no damage to lysosomal integrity was observed, suggesting that the cytotoxic effect evoked by L interned:a venom on endothelial cells is not mediated by venom internalization (C) 2010 Elsevier Ltd. All rights reserved

Avian Infectious Bronchitis Virus in Brazil: A Highly Complex Virus Meets a Highly Susceptible Host Population

Infectious bronchitis (IB) is a highly aggressive disease for poultry in terms of symptoms and economic losses, and the control of this disease is difficult if flocks are not protected against type-specific challenges by the Avian infectious bronchitis virus (IBV). This article summarizes data presented by the author at the Workshop on Infectious Bronchitis 2009 on IB and IBV, including future developments on the field.

Serosurvey Of Selected Avian Pathogens In Brazilian Commercial Rheas (Rhea americana) And Ostriches (Struthio camelus)

Ratite farming of has expanded worldwide. Due to the intensive farming methods used by ratite producers, preventive medicine practices should be established. In this context, the surveillance and control of some avian pathogens are essential for the success of the ratite industry; however, little is known on the health status of ratites in Brazil. Therefore, the prevalence of antibodies against Newcastle Disease virus, Chlamydophila psittaci, Mycoplasma gallisepticum, Mycoplasma synoviae, and Salmonella Pullorum were evaluated in 100 serum samples collected from commercial ostriches and in 80 serum samples from commercial rheas reared in Brazil. All sampled animals were clinically healthy. The results showed that all ostriches and rheas were serologically negative to Newcastle disease virus, Chlamydophila psittaci, Myco plasma gallisepticum, and Myco plasma synoviae. Positive antibody responses against Salmonella Pullorum antigen were not detected in ostrich sera, but were detected in two rhea serum samples. These results can be considered as a warning as to the presence of Salmonella spp. in ratite farms. Therefore, the implementation of good health management and surveillance programs in ratite farms may contribute to improve not only animal production, but also public health conditions.

Tecnologias ambientais: em busca de um significado

Este artigo busca um significado mais preciso e completo para um termo cuja adoção revela-se crescente nos fóruns acadêmicos e empresariais: tecnologia ambiental. De fato, o desenvolvimento, a adoção e a difusão de tecnologias ambientais implicam o envolvimento de diversos agentes, instituições e setores sociais, que requerem um entendimento comum e devidamente completo para o significado de tecnologia ambiental. Entretanto, as propostas conceituais mais atuais são tímidas diante do desafio de se buscar um significado mais claro para o termo. Assim, este artigo explora a tipologia do termo e identifica seu processo de desenvolvimento e difusão, fornecendo um significado mais completo de tecnologia ambiental.