MÚLTIPLOS APRENDIZADOS NO ENSINO DE FRAÇÕES E NÚMEROS DECIMAIS NA EDUCAÇÃO BÁSICA

A proposta deste trabalho é fazer o resgate do ensino de fração na Educação Básica. A ideia inicial é fazer um histórico sobre fração e números decimais, identificando quando e como surgiram os primeiros registros e a partir de qual necessidade foram introduzidos nas sociedades. A partir daí, será feita uma apresentação sobre o ensino de fração na atualidade e como estão os índices relativos ao Brasil. Para que se entenda este processo, será apresentado, neste trabalho, um diagnóstico qualitativo feito com professores da Educação Infantil e Ensino Fundamental (1ª Fase) sobre tempo de atuação, formação em Matemática e formação em frações e decimais, entre outros. Será feita uma análise de questionários específicos, aplicados para alunos de 5º ano e 9º ano do Ensino Fundamental, e da 3ª série do Ensino Médio, com questões específicas de modelos aplicados no SAEB (Sistema de Avaliação da Educação Básica) com os respectivos descritores dos conteúdos estudados. Em seguida, serão discutidas as respostas dadas pelos alunos. Consta também, neste trabalho, uma proposta de intervenção para o ensino de fração com exercícios e discussões de possíveis soluções para facilitar o aprendizado do conteúdo

Preliminary conceptual model of the Cerro Blanco caldera-hosted geothermal system (Southern Puna, Argentina): Inferences from geochemical investigations.

The Cerro Blanco Caldera (CBC) is the youngest collapse caldera system in the Southern Central Andes (Southern Puna, Argentina). The CBC is subsiding with at an average velocity of 0.87 cm/year and hosts an active geothermal system. A geochemical characterization of emitted fluids was carried out based on the chemical and isotopic compositions of fumaroles, and thermal and cold springs discharged in this volcanic area with the aim of constructing the first hydrogeochemical conceptual model and preliminary estimate the geothermal potential. The main hydrothermal reservoir, likely hosted within the pre-caldera basement rocks, has a Na+-Clˉ(HCO3)ˉ composition with estimated temperatures ≥135 °C. The unconsolidated, fine-grained Cerro Blanco ignimbrite likely acts as the cap-rock of the hydrothermal system. The presence of phreatic eruption breccias in the surrounding area of the geothermal fumaroles supports the effectiveness of the pyroclastic deposit as sealing rocks. The isotopic data of water (δ18O and δD) indicate a meteoric recharge of the hydrothermal reservoir, suggesting as recharge areas the sectors surrounding the CBC, mainly towards the W and NW where large outcrops of the pre-caldera basement exist. A fault-controlled hydraulic connection between the hot springs and the hydrothermal reservoir is proposed for the Los Hornitos area. The fumaroles show the typical compositional features of hydrothermal fluids, being dominated by water vapor with significant concentrations of H2S, CH4 and H2. Considering the high geothermal gradient of this area (∼104 °C/km) and the relatively high fraction of mantle He (∼39%) calculated on the basis of the measured R/Ra values, the hydrothermal aquifer likely receives inputs of magmatic fluids from the degassing magma chamber. The preliminary geothermal potential at CBC was evaluated with the Volume Method, calculating up to E = 11.4*1018 J. Both the scarce presence of superficial thermal manifestations and the occurrence of an efficient cap-rock likely contribute to minimize the loss of thermal energy from the reservoir. The results here presented constitute the necessary base of knowledge for further accurate assessment of the geothermal potential and ultimately the implementation of the geothermal resource as a viable energy alternative for small localities or mining facilities isolated from the National Interconnected System due to their remote localization.Published1022136A. Geochimica per l'ambiente e geologia medicaJCR Journa

Pulsating flow dynamics of sustained, forced pyroclastic density currents: insights from a facies analysis of the Campo de la Piedra Pómez ignimbrite, southern Puna, Argentina

The Quaternary Campo de la Piedra Pomez ignimbrite (CPPI) is a superbly exposed, partially indurated, rhyolitic ignimbrite emplaced on the southern Puna of Argentina. It is characterized by a variety of facies that record in unprecedented detail the flow dynamics of the parent pyroclastic density currents (PDCs). Detailed facies analysis and internal architecture defined using a sequential stratigraphy approach reveal that CPPI was formed by sustained PDCs, generated from a low fountain eruptive style (boiling over). The PDCs had overall flow conditions characterized by high particle concentration and limited capability to surmount topographic obstacles. The mobility of the PDCs was largely controlled by high pore pressure and the continuous supply at the source (sustained forced convection-dominated PDCs). The successive forestepping-backstepping stacking patterns identified in the CPPI reflect a marked unsteadiness of its parent PDCs due to a pulsating discharge rate at the source. The lateral facies variations in the CPPI record the non-uniform character of its parent PDCs as they flowed outward from the base of the collapsing fountain. Proximal-medial areas characterized by steady aggradation rates pass through to distal braided thalwegs with highly variable aggradation rates, to frontal edges characterized by the step aggradations of secondary decoupled pumice-rich lobes. Collectively, the facies variations in the CPPI record the complex dynamics of sustained PDCs that include pulsating discharge rate at the source, progressive modification of the original topography, and lateral flow transformations

Prevalência de helicobactérias e alterações na mucosa gástrica de cães saudáveis Prevalence of helicobacters and alterations in gastric mucosa of healthy dogs

<abstract language="eng">Prevalence, distribution and density of gastric helicobacter colonization were determined in 50 healthy dogs, characterizing the macroscopic and microcospic aspects of their mucosa. Helicobacter prevalence was 96%, with greater distribution in the gastric fundus and body. Although the presence of macroscopic alterations was high (58%), it was characterized as mild due to the predominance of less severe ones (65.5%). High prevalence of mostly monoclear cell infriltate (64.7%) was noted. Association between the presence of helicobacter and macro and microscopic alterations was not observed

Adenoma pleomórfico de parótida: aspectos clínicos, diagnósticos e terapêuticos Parotid pleomorphic adenoma: clinical, diagnostic and therapeutical aspects

As neoplasias da glândula parótida constituem um grupo heterogêneo com mais de 30 tipos histológicos definidos, sendo o adenoma pleomórfico o tumor benigno mais comum. OBJETIVO: Neste trabalho apresentamos uma casuística de adenoma pleomórfico de glândula parótida, com o objetivo de discutir a apresentação clínica, o diagnóstico e as técnicas cirúrgicas mais adequadas no tratamento desta doença. MATERIAL E MÉTODO: Foi realizado estudo clínico retrospectivo de um grupo de 68 pacientes com diagnóstico histopatológico de adenoma pleomórfico de glândula parótida, operados no Serviço de Otorrinolaringologia do HSPE-FMO, de janeiro de 1982 a junho de 2002. Foram colhidos os dados referentes a idade, sexo, sintomas mais freqüentes, exames complementares, localização, tamanho, técnica cirúrgica empregada, complicações do tratamento e evolução. RESULTADOS: Nesta casuística observamos maior incidência no sexo feminino, e mais freqüente na 5ª década de vida. A apresentação clínica mais comum foi nódulo na região parotídea, sendo este sinal presente em 100% dos casos. A parotidectomia superficial com identificação e preservação do nervo facial foi a cirurgia mais realizada (91,2% dos casos). As complicações pós-operatórias mais freqüentes foram paresia (14,7%) e paralisia (7,3%) do nervo facial, seguida da síndrome de Frey (4,4%). CONCLUSÃO: O adenoma pleomórfico é a neoplasia benigna mais comum na glândula parótida, sendo mais freqüente no sexo feminino, a partir da 5ª década de vida. É uma neoplasia de diagnóstico clínico, com confirmação a partir do exame histopatológico. A parotidectomia superficial é procedimento mínimo para o diagnóstico e terapêutica, sendo baixa a taxa de recidiva com esta cirurgia.<br>The neoplasias of the parotid gland are a heterogeneous group with more than 30 histological kinds already defined, and the pleomorphic adenoma is the most common benign tumor. AIM: In this study we present our case of parotid gland pleomorphic adenoma, with the purpose of discussing the clinical presentation, the diagnosis and the more suitable surgical techniques to treat this disorder. MATERIAL AND METHOD: A retrospective clinical study was carried out on a group of 68 patients with histological diagnosis of parotid gland pleomorphic adenoma who underwent surgery at the Department of Otolaryngology of the HSPE-FMO, from January 1982 to June 2002. The data regarding their age, sex, more frequent symptoms, supplementary tests performed, location, size, surgical technique used, treatment complications and evolution were gathered. RESULTS: In our case we observed a higher incidence in female patients, being more frequent in their fifth decade of life. The most common clinical presentation was of a nodule at the parotid region, this sign being present in 100% of the cases. Superficial parotidectomy by identifying and preserving the facial nerve was the more common surgery (91.2 % of the cases). The more frequent post-surgical complications were paresis (14.7%) and paralysis (7.3%) of the facial nerve, followed by the Frey's syndrome (4.4%). CONCLUSION: The pleomorphic adenoma is the most common benign neoplasia of the parotid gland, being more frequent in female patients from their fifth decade of life. It is a clinically diagnosable neoplasia, to be confirmed with a histopathological examination. The superficial parotidectomy is the basic procedure to diagnose and treat it, being low the recurrence index with this surgery