bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluación de un proceso de capacitación para extensionistas rurales implementado en Paraguay
Authors: Landini Fernando Pablo , Bianqui Vanina , Russo Mabel
Published: April 2014

Se implementó una metodología, innovadora en el contexto paraguayo, para capacitar extensionistas rurales del departamento de Caazapá. Esta capacitación se caracterizó por orientarse al fortalecimiento y a la transformación de las prácticas de extensión, buscando desarrollar un modelo más horizontal y participativo de interacción. Para esto se implementaron ocho módulos de capacitación de carácter mensual donde se incorporaron procesos reflexivos sobre los problemas a los que enfrentan los extensionistas en su práctica y espacios para la construcción de propuestas para superarlos. En este artículo se describe y evalúa tanto la implementación como el impacto de la capacitación en las creencias de los extensionistas, tanto a nivel cualitativo como cuantitativo. La evidencia muestra que la metodología implementada transformó significativamente el modo en que los técnicos comprenden su rol en el trabajo de extensión. En concreto, ahora se conciben como facilitadores que trabajan de manera conjunta con los productores en lugar de como quienes tienen que aportar todas las soluciones.
Una tipología de los nuevos habitantes del campo: aportes para el estudio del fenómeno neorrural a partir del caso de Manizales, Colombia
Authors: Méndez Sastoque Marlon Javier
Published: April 2014

El artículo presentar una propuesta tipológica de los nuevos y diversos habitantes del campo, asumiendo como sustento el caso de Manizales, Colombia. Se construyó mediante el análisis de información producto de entrevistas semi-estructuradas centradas en las motivaciones para migrar de la ciudad al campo y el proceso de inmersión de los migrantes al espacio social de acogida. El análisis permitió establecer cuatro tipos de nuevos habitantes del campo: a) neorrurales por atracción comparativa, b) neorrurales por atracción ético-política, c) neorrurales por atracción económico-productiva, y d) neorrurales por expulsión. Se concluye que el neorruralismo es una expresión localizada, variable en relación con el dominio o contexto de ocurrencia.
Deliberacionismo e os limites da crítica: uma resposta
Authors: Miguel Luis Felipe
Published: April 2014

O artigo apresenta uma resposta ao texto "Teoria crítica e democracia deliberativa", de Ricardo Fabrino Mendonça (Opinião Pública, vol. 19, nº 1). Em vez de analisar a fidelidade das atuais teorias democrático-deliberativas ao legado da Escola de Frankfurt, busca-se compreender o quanto elas mantêm do impulso emancipatório original. A avaliação é que a teoria deliberativa encontra-se presa a um trade-off entre uma normatividade abstrata, incapaz de uma intervenção efetiva na realidade, e a acomodação com as instituições e práticas das democracias liberais realmente existentes.
Literary studies in Romania before and after 1989
Authors: Schneider Ana-Karina
Published: April 2014

In comparative terms, after the strict cultural policies and censorship of the communist regime, the literature and literary studies of post-communist Romania would seem to be almost completely free of the political. This article investigates the complex ways in which various aspects of the study and reception of English literature - from the practice of teaching English, through textbooks, to literary translation - reflect the evolution of the relationship between literature and politics in pre- and post-1989 Romania. In the asymmetrical cultural exchange resulting from the inevitable hierarchy in which Anglo-American culture is dominant, whereas Romanian culture is perpetually subordinate, the latter embraces its marginality and places itself strategically at the receiving end. I therefore argue that while Anglo-American scholars' concern with the pernicious outcomes of Anglocentricity in ES is in itself a laudable ethical move, in target cultures such as the Romanian, Anglocentricity may function as a catalyst of resistance and change.
Ao preço da minha boca: poesia romena pós-comunista
Authors: Mysjkin Jan H.
Published: April 2014

O artigo esboça um panorama da poesia romena a partir de 1947, quando os comunistas tomaram o poder e estabeleceram uma ditadura que durou até o final de 1989. De década a década, o autor acompanha a evolução da poesia até a geração mais recente, que não conheceu a era comunista.
Tradição e modernidade na obra de Lucian Blaga
Authors: Grigore Rodica
Published: April 2014

Lucian Blaga, poeta e filósofo, é, depois de Mihai Eminescu, o elo mais importante na cultura romena entre a tradição e a modernidade, entre uma "era heroica" de provação e sobrevivência e a nova época de consolidação. Blaga era um poeta de uma vocação dupla, um inovador e também um consolidador. Se os seus poemas de juventude expressam o espírito de uma modalidade transformada de expressionismo, os de maturidade ilustram uma atitude mais cética em relação à realidade. É claro, todos esses poemas iluminam e são iluminados por diferentes facetas da filosofia de Blaga; e ao mesmo tempo eles tornam problemáticos os aspectos conceituais de sua obra, submetendo-os a uma interrogação poética. Lucian Blaga foi o primeiro poeta romeno cuja obra estava sincronizada com formas artísticas europeias essenciais, e sua maior conquista talvez tenha sido a de adaptar o expressionismo para a poesia romena, mas sempre conseguindo manter uma direção original em sua obra, reavaliando os modelos e adaptando a "vontade de modernidade" para a cultura romena.
The two english versions of Mioritza
Authors: Olaru Victor
Published: April 2014

This paper proposes a short comparative analysis of two English translations of the Romanian poem Mioritza, the first from 1856, made by Henry Stanley, and the second, by the American Poet W.D. Snodgrass, from 1972. It is argued that the latter has more poetic value, for it utilizes rhyme patterns and a meter closer to the Romanian ballad.
Proposta para estimar curva carga-recalque e capacidade de carga em estacas de madeira
Authors: Segundinho Pedro Gutemberg de Alcântara , Miná Alexandre José Soares , Dias Antonio Alves , Regazzi Adair José , Carreira Marcelo Rodrigo
Published: April 2014

Este trabalho teve como objetivo propor um método para estimar a curva carga-recalque e a capacidade de carga de estacas de madeira a partir do ajuste de equações de regressão não lineares utilizando o método de Gauss Newton modificado. Para isso, foram utilizados dados experimentais obtidos para 12 estacas de madeira, curvas carga-recalque durante a cravação e capacidade de carga determinada no ensaio de carregamento dinâmico, utilizando modelo teórico. Nesta pesquisa, realizada de forma pioneira no Brasil, fez-se a análise do comportamento de estacas de madeira imersas no solo durante a cravação delas. As médias do erro percentual absoluto médio foram 4,0% e 29,3%, obtidas a partir das equações não lineares ajustadas via método de Gauss Newton modificado e proposto por Van Der Veen respectivamente. Concluiu-se que as equações ajustadas via método de Gauss Newton modificado conduziram a uma maior exatidão nas estimativas, apresentando boa concordância com os dados experimentais obtidos nos ensaios de carregamento dinâmico, indicando sua utilização para estimar a curva carga-recalque e a capacidade de carga em estacas de madeira.
Utilização de termografia infravermelha para avaliação de fissuras em fachadas com revestimento de argamassa e pintura
Authors: Freitas Juliana Gomes de , Carasek Helena , Cascudo Oswaldo
Published: April 2014

As fachadas dos edifícios estão expostas aos fenômenos climatológicos da região em que se localizam. A falta de adequada compreensão da interação entre os ciclos de temperatura e de umidade e os revestimentos de fachada favorece sua degradação. Nesse contexto, o monitoramento e o estudo do efeito desses aspectos físicos são importantes para a garantia da durabilidade das fachadas. Em outros países a termografia infravermelha vem sendo utilizada como técnica não destrutiva para a avaliação de problemas nas edificações. Nesse sentido, o presente trabalho tem como objetivo aplicar a termografia na avaliação de manifestações patológicas relacionadas à temperatura em revestimentos de fachadas. Para tanto, realizaram-se imagens utilizando um termovisor em diferentes horários do dia nas estações seca e chuvosa em uma edificação da cidade de Goiânia, GO. Aferiu-se também a temperatura superficial, em pontos das quatro orientações das fachadas. Por fim, mapearam-se as manifestações patológicas existentes com o auxílio de programa computacional. Como resultado, verificou-se que parte das fissuras levantadas foi visualizada nas imagens térmicas. Verificou-se, também, que o período seco e o horário da tarde provocaram maiores diferenças nas temperaturas superficiais, resultando em isotérmicas mais claras, o que possibilitou a obtenção de imagens que revelaram alguns dos problemas mapeados.
Caracterização reológica de suspensões cimentícias mistas com cales ou filitos
Authors: Romano Roberto Cesar de Oliveira , Seabra Mauro Adamo , John Vanderley Moacyr , Pileggi Rafael Giuliano
Published: April 2014

Filitos são tipos de rochas metamórficas que vêm sendo utilizados ultimamente como insumos em composições de argamassa de revestimento, em substituição à cal. A melhora da trabalhabilidade e da plasticidade dos materiais cimentícios, principais motivos para a utilização das cales, são as características obtidas também com a utilização dos filitos. Este trabalho tem como objetivo avaliar as características de suspensões cimentícias formuladas com cal ou filito, a partir de ensaios de reometria rotacional para a avaliação das propriedades das suspensões durante o fluxo, e oscilatória para a avaliação da cinética de consolidação. Os resultados mostraram que, apesar de as características físicas, químicas e mineralógicas dos pós serem muito diferentes, as cales hidratadas do tipo I (CHI) não se diferenciaram dos filitos durante o fluxo, mas durante o endurecimento foram observadas consideráveis alterações na cinética de aglomeração.
Dosagem de concretos produzidos com agregado miúdo reciclado de resíduo da construção civil
Authors: Rodrigues Clarissa Ribeiro de Sá , Fucale Stela
Published: April 2014

Esta pesquisa apresenta uma investigação sobre concretos confeccionados com agregado reciclado de resíduo da construção civil (RCC), com a finalidade de observar a influência da utilização desse material nas características mecânicas dos concretos. O material utilizado foi coletado em uma obra na Região Metropolitana do Recife, PE, na fase de estrutura, constituído por cerca de 70% de concreto. Foi realizado um estudo de dosagem experimental em concretos com 0%, 50% e 100% de substituição do agregado miúdo natural pelo reciclado, em massa. Foram analisadas as características dos concretos no estado fresco e endurecido. Após a obtenção dos resultados dos ensaios, foram construídos diagramas de dosagem, em que foi possível estudar as correlações entre as propriedades mecânicas dos concretos e as variáveis que influenciam esses parâmetros. Observou-se que os concretos reciclados apresentaram um aumento de volume de argamassa seca, devido às diferenças existentes nos valores de massa específica entre o material natural e o reciclado. Percebeu-se, ainda, que com a substituição do agregado miúdo natural pelo reciclado houve um incremento na absorção de água e consumo de cimento do concreto reciclado. Houve a diminuição do módulo de elasticidade, o que, contudo não causou grandes prejuízos à resistência à compressão do concreto reciclado, sendo o teor de 50% em massa de substituição do agregado miúdo natural pelo reciclado o mais adequado.
Phylogenetic relationships of the enigmatic Carlastyanax aurocaudatus (Eigenmann) with remarks on the phylogeny of the Stevardiinae (Teleostei: Characidae)
Authors: Mirande Juan Marcos , Jerep Fernando Camargo , Vanegas-Ríos James Anyelo
Published: April 2014

The monotypic genus Carlastyanax Géry was defined to include Astyanax aurocaudatus, a morphologically odd species having, among other features, four teeth in the posterior premaxillary row and eight branched dorsal-fin rays. Later on, the characters used to define Carlastyanax were considered as invalid and this genus was synonymized with Astyanax. In this paper, we include Astyanax aurocaudatus in a phylogeny of the Characidae and obtain a sister-group relationship between this species and Creagrutus, within the Stevardiinae. The resurrection of Carlastyanax as a valid genus is therefore proposed. The analysis presented is the largest phylogeny of the Stevardiinae so far published. Relationships of this subfamily are also discussed.
Parotocinclus seridoensis, a new hypoptopomatine catfish (Siluriformes: Loricariidae) from the upper rio Piranhas-Açu basin, northeastern Brazil
Authors: Ramos Telton Pedro A. , Barros-Neto Luciano F. , Britski Heraldo A. , Lima Sergio M. Q.
Published: April 2014

A new species of Parotocinclus is described from the upper rio Piranhas-Açu basin, northeastern Brazil. The new species differs from all its congeners, except P. bidentatus, P. muriaensis (both from rio Paraíba do Sul basin, southeastern Brazil), and P. spilurus (rio Jaguaribe basin, northeastern Brazil) by presenting the adipose fin rudimentary or absent. The new species differs from P. bidentatus, P. muriaensis, and P. spilurus mainly by presenting the abdomen region extensively naked, with few reduced rounded dermal platelets between the pectoral girdle and the anus. Parotocinclus seridoensis is probably an endemic species of the semi-arid Caatinga, region where the genus presents high species richness.
Morphological analysis and description of the ovaries of female silky sharks, Carcharhinus falciformis (Müller & Henle, 1839)
Authors: Rêgo Mariana G. , Hazin Fábio H. V. , Evêncio Neto Joaquim , Oliveira P. G. V. , Soares Maria Goretti , Torres Keilla Regina L. S. , Lana Fernanda O. , Roque Pollyana C. G. , Santos Natália L. , Coelho Rui
Published: April 2014

This work aims to study the female reproductive tract of silky sharks, Carcharhinus falciformis, captured in the South and Equatorial Atlantic Ocean. Samples were collected between January 2008 and March 2010 through oceanic commercial vessels that targeted tuna and swordfish, with a total of 17 females collected. The methodologies followed for analyzing the ovaries of those females included both macroscopic and histological analysis. Macroscopically, it was possible to determine that the ovaries on these sharks is suspended by mesenteries in the anterior section of the body cavity, heavily irrigated by blood vessels, and contains a wide range of oocytes. Ovaries were found in three distinct maturational stages: Stage I (Immature), Stage II (Maturing) and Stage III (Mature). Immature ovaries were small, with widths ranging from 1.0 to 3.1 cm, and had a gelatinous or granulose internal structure; maturing ovaries were slightly larger, ranging in width between 5.2 and 6.0 cm; mature ovaries ranged in width between 6.5 and 7.8 cm, and had a more rounded shape and the presence of large and well developed oocytes. Under microscopic examination, it was observed that the ovaries were covered with simple epithelial tissue during the early development stages and a simple cubic epithelium in the final stages of maturation. During the initial maturation stages the epigonal organ was not differentiated from the ovary. In mature specimens, the ovary showed a simple cubic epithelium and just below this epithelium there was a layer of dense connective tissue and muscle with the presence of vitellogenic oocytes and fat cells. A thin yolk membrane enclosing the oocytes was also evident. Finally, it was possible to distinguish a zona pellucida, separating the oocytes from the follicle wall and a basal lamina between the granular layers and the teak layer.
Ultrastructure of fresh and post thawed sperm of pejerrey Odontesthes bonariensis (Atheriniformes)
Authors: Gárriz Ángela , Miranda Leandro A.
Published: April 2014

In the present study it was showed for the first time the ultrastructural morphology of O. bonariensis sperm using electron microscopy techniques. Different kinds of abnormalities were described in fresh and post thawed sperm caused by crogenic protocols. Pejerrey spermatozoon is uniflagellated and is differentiated into three parts: a small roundish head (~1.80µm in length and 1.67µm in width), a midpiece or transitional region (~1.11µm in length and 1.56µm in width), and a long tail or flagellum (~29.08µm). Samples of fresh and post thawed sperm showed evidence of morphological anomalies affecting various intracellular compartments. Spermatozoa with swollen, ruptured, or absent membranes in the head showing excess of cytoplasm, and with alteration of the spatial orientation of the mitochondria were observed. A swollen flagellum was observed containing cytoplasmic vesicles, distributed along the whole length or concentrated in a restricted part of the tail. It was also found a high level of abnormalities (60%) in frozen sperm when compared with normal sperm (18%) reflecting the damage provoked by cryopreservation procedures.
Habitat preferences of common native fishes in a tropical river in Southeastern Brazil
Authors: Costa Marcus Rodrigues da , Mattos Tailan Moretti , Borges Joyce Liz , Araújo Francisco Gerson
Published: April 2014

We determined in this study the habitat preferences of seven native fish species in a regulated river in Southeastern Brazil. We tested the hypothesis that fishes differ in habitat preference and that they use stretches of the river differing in hydraulic characteristics and substrate type. We surveyed fishes in four 1-km long river stretches encompassing different habitat traits, where we also measured water depth, velocity, and substrate type. We investigated preference patterns of four Siluriformes (Loricariichthys castaneus, Hoplosternum littorale, Pimelodus maculatus, and Trachelyopterus striatulus) and three Characiformes (Astyanax aff. bimaculatus, Oligosarcus hepsetus, and Hoplias malabaricus), representing approximately 70% of the total number of fishes and 64% of the total biomass. We classified fishes into four habitat guilds: (1) a slow-flowing water guild that occupied mud-sand substrate, composed of two Siluriformes in either shallow (< 4 m, i.e., H. littorale) or deep (> 8 m, L. castaneus) waters; (2) a run-dwelling guild that occurs in deep backwaters with clay-mud substrate, composed of the Characiformes A. aff. bimaculatus and O. hepsetus; (3) a run-dwelling guild that occurs in sandy and shallow substrate, composed of T. striatulus; and (4) a fast-flowing guild that occurs primarily along shorelines with shallow mud bottoms, composed of H. malabaricus and P. maculatus. Our hypothesis was confirmed, as different habitat preferences by fishes appear to occur in this regulated river.
Fish diet composition in permanent and semi-permanent pools in tropical wetlands of the Yucatan Peninsula
Authors: Hinojosa-Garro Demián , Arceo-Gómez Joselito , Zambrano Luis , Escalera-Vázquez Luis H.
Published: April 2014

We compared fish diet composition between permanent (P) and semi-permanent (SP) pools in Petenes Biosphere Reserve (PBR), Campeche. A total of 445 gut contents were examined to determine stomach relative fullness (RF), fish diet as index of niche breadth (INB) and diet overlap. In SP pools, species showed a RF of 1.66 (57.20 % empty stomachs) whereas in P pools, the RF was 2.91 (31.16%). We classified fish diet into six trophic groups: detritivorous, herbivorous-detritivorous, insectivorous, piscivorous, omnivorous and malacophagous. Species in P pools were found to be specialist. Conversely, species present in both habitats shifted to generalist patterns. There was a 54.0% dissimilarity in fish diet composition between pools. From all items identified, detritus (21.33% of the total dissimilarity), aquatic and terrestrial invertebrates (12.31%), fish remains (10.29%), plant remains (7.37%), and crustaceans (2.74%) distinguished diets between pools. Significant diet overlaps (>0.6) and low INB values (<0.3) were observed in P pools, whereas in SP pools, intermediate-low diet overlaps (<0.4) and higher INB values (>0.5) were observed. In SP pools seasonality had a strong effect on fish diet, increasing the frequency of food items such as terrestrial insects, amphipods and arachnids, during the rainy season while P pools showed lower variation. Thus, fish trophic habits appear to be regulated by pools hydrology.
Taxonomic revision of SpectracanthicusNijssen & Isbrücker (Loricariidae: Hypostominae: Ancistrini), with description of three new species
Authors: Chamon Carine C. , Py-Daniel Lúcia H. Rapp
Published: April 2014

A taxonomic review of Spectracanthicus Nijssen & Isbrücker, including Oligancistrus Rapp Py-Daniel, following a phylogenetic study, is presented. Additionally to S. punctatissimus(Steindachner) and S. murinus Nijssen & Isbrücker, three new species are recognized based on the examination of 159 specimens: S. immaculatus n. sp. from rio Tapajós basin, differs from its congeners by its color pattern consisting of a dark gray body, with no dots or spots, and by having very slender teeth; Spectracanthicus tocantinensisn. sp., from the rio Tocantins drainage is distinguished by the color pattern consisting of dark brown or black body with small, yellowish dots (except in S. punctatissimus), presence of thick teeth, infraorbital 4 forming most of the posterior edge of the orbit and the large basipterigium fenestrae; and Spectracanthicus zuanonin. sp., from the rio Xingu basin is diagnosed by its color pattern consisting of large, white spots and by the larger orbital diameter. Other characters based on osteological features are also usefull to distinguish the species. A key to the species of the genus and a brief discussion of their threats and conservation are also provided.
Miniaturization in Otothyris Myers, 1927 (Loricariidae: Hypoptopomatinae)
Authors: Rosa Alaina Cristine , Langeani Fernanda de Oliveira Martins and Francisco
Published: April 2014

Many species of freshwater fishes are considered miniatures, nevertheless, their identification as miniatures is frequently based only on an arbitrary criterion of small body size. Although some species of Otothyris had been suggested to be miniature, informations about the process and consequences of miniaturization in the genus are lacking. Here, we detail developmental events of loss, fusion, and modifications in several bones, the laterosensory system, and even the brain, that in sum demonstrate miniaturization in all species of the genus. Our results may be useful in the recognition of other miniature species of loricariids.
A new long-finned Corydoras Lacépède, 1803 (Siluriformes: Callichthyidae) from the lower rio Paraná basin, Brazil
Authors: Tencatt Luiz F. C. , Britto Marcelo R. , Pavanelli Carla S.
Published: April 2014

A new species of Corydoras is described from the lower rio Paraná basin, just downstream from Itaipu Dam, Brazil, close to Paraguay boundary. The new species can be distinguished from most of its congeners by the infraorbital 2 with a posterior laminar expansion conspicuously reduced, first and second dorsal-fin branched rays conspicuously elongated in males, mesethmoid entirely covered by skin, and by the presence of four to six irregular black or brownish blotches on the midline of the flank. The probable occurrence of the new species in the floodplain of the upper portion of the rio Paraná drainage is discussed.
A new species of Corydoras Lacépède, 1803 (Siluriformes: Callichthyidae) from the upper rio Paraná basin, Brazil
Authors: Tencatt Luiz F. C. , Britto Marcelo R. , Pavanelli Carla S.
Published: April 2014

A new species of Corydorasis described from three tributaries of the rio Ivaí drainage, upper rio Paraná basin, Paraná State, Brazil. The new species can be distinguished from most of its congeners by the presence of three nasal pores. Other diagnostic features are the lower number of serrations in posterior margin of pectoral and dorsal spines and presence of four to six small black blotches along the midline of the flank. The possible mimetic relationship between the new species and Characidium heirmostigmatais discussed.
Discovery of endangered annual killifish Austrolebias cheradophilus (Aplocheiloidei: Rivulidae) in Brazil, with comments on habitat, population structure and conservation status
Authors: Lanés Luis Esteban Krause , Gonçalves Ândrio Cardozo , Volcan Matheus Vieira
Published: April 2014

Austrolebias genus comprises about 40 small annual killifishes endemic to South America and their highest diversity occurs in southern Brazil and Uruguay, especially in drainages of Patos-Mirim system. Austrolebiasspecies are severely threatened with extinction because their life cycle and restricted ranges. Low dispersal ability and the extensive loss and fragmentation of freshwater wetlands contribute to this threat. Accurate information on the geographic distribution and ecology of the species, vital to plan conservation and management strategies, are scarce. In order to provide basic knowledge for annual fish conservation this paper reports the presence of Austrolebias cheradophilus and present data about its population structure (CPUA, size, sex ratio, length-weight relationships and condition factor) and conservation status in southern Brazil. The estimated CPUA of populations was 0.86 fish/m2. Standard length (SL) of males ranged between 32.14 and 49.17 mm and for females between 25.11 and 41.6 mm. There were no differences in SL between the sexes (t-test = - 1.678; P = 0.105), and Chi-squared test demonstrated marginal differences in proportions of sexes (2.25:1; χ2 = 3.846; P= 0.07). Allometric coefficient of the LWR was slightly hyperallometric (b = 3.08) and K of the specimens ranged from 1.84 to 2.42 (mean ± S.E. = 2.12 ± 0.04). Populations have low density and their biotopes are under critical threat, mainly due to suppression by agriculture, pastures for livestock and increase housing. The species is considered "Critically Endangered" in Brazil, furthermore is strongly recommended its inclusion on lists of endangered fauna and ensures the protection of their remaining habitats.
Disentangling the influences of habitat structure and limnological predictors on stream fish communities of a coastal basin, southeastern Brazil
Authors: Ferreira Fabio Cop , Silva André Teixeira da , Gonçalves Cristina da Silva , Petrere Jr. Miguel
Published: April 2014

In stream environments habitat structure and limnological factors interact regulating patterns of energy and material transfer and affecting fish communities. In the coastal basins of Southeastern Brazil, limnological and structural characteristics differ between clear and blackwaters streams. The former have a diversity of substrate types, higher water velocities, and lower water conductivity, while the latter have sandy substrate, tea-colored and acidic waters, and low water velocities. In this study, we verified the relative importance of habitat structure and limnological variables in predicting patterns of variation in stream fish communities. Eight first to third order streams were sampled in the coastal plain of Itanhaém River basin. We captured 34 fish species and verified that community structure was influenced by physical habitat and limnology, being the former more important. A fraction of the variation could not be totally decomposed, and it was assigned to the joint influence of limnology and habitat structure. Some species that were restricted to blackwater streams, may have physiological and behavioral adaptations to deal with the lower pH levels. When we examined only the clearwater streams, all the explained variation in fish community composition was assigned to structural factors, which express specific preferences for different types of habitats.
Ionosphere-magnetosphere coupling and field-aligned currents
Authors: Oliveira D.
Published: April 2014

It is presented in this paper a review of one of several interactions between the magnetosphere and the ionosphere through the field-aligned currents (FACs). Some characteristics and physical implications of the currents flowing in a plane perpendicular to the magnetic field at high latitudes are discussed. The behavior of this system as an electric circuit is explained, where momentum and energy are transferred via Poynting flux from the magnetosphere into the ionosphere.
Refrigerador termoelétrico de peltier usado para estabilisar um feixe laser em experimentos didáticos
Authors: Moura Paulo Roberto de , Almeida Danilo
Published: April 2014

É apresentado um experimento onde os alunos montam um sistema de estabilização térmica de um laser de diodo mantido a temperatura controlada e estabilizada utilizando materiais de baixo custo. Um circuito de controle baseado no efeito Peltier foi montado para estabilizar um sistema ótico composto de uma ponteira laser e de optodiodos para a detecção dos feixes espalhados e transmitido. Os efeitos físicos associados são discutidos permitindo aos estudantes a fixação dos conteúdos teóricos na área de termodinâmica e de semicondutores.
O modelo ondulatório da luz como ferramenta para explicar as causas da cor
Authors: Scarinci Anne L. , Marineli Fábio
Published: April 2014

O presente texto trata dos efeitos da interação luz-matéria que resultam nas cores que enxergamos, assunto que geralmente não é tratado adequadamente em aulas de física. São feitas algumas considerações sobre percepção visual e, em seguida, procuramos nos centrar em explicações para as causas da cor que utilizam o eletromagnetismo clássico (luz como onda eletromagnética) e o modelo de Drude-Lorentz (osciladores moleculares e eletrônicos). Esse modelo subsidia o entendimento dos fenômenos de espalhamento, reflexão, refração e reflexão-refração difusa. Ao final do texto, para efeito de comparação e para ampliar o entendimento dos fenômenos relacionados à cor, também abordamos algumas causas da cor que exigem a utilização de um modelo quântico para a luz.
Modelo clássico para resfriamento atômico: Uma forma pedagógica de entender o problema
Authors: Gomes N.D. , Caracanhas M.A. , Bagnato V.S.
Published: April 2014

Neste trabalho desenvolvemos um modelo clássico para descrever o processo de resfriamento atômico devido à interação de um átomo com uma configuração de feixes de luz laser. Derivamos uma expressão para a força de radiação sobre o átomo com a descrição detalhada da origem de cada um dos termos envolvidos. Por fim construímos um paralelo entre o aspecto clássico e as particularidades da natureza quântica da interação radiação matéria.
Construção de um dilatômetro e determinação do coeficiente de dilatação térmica linear
Authors: Pizetta Daniel Cosmo , Mastelaro Valmor Roberto
Published: April 2014

O estudo da dilatação térmica linear dos sólidos é de grande importância para diferentes áreas da física e engenharias como, por exemplo, a construção civil onde a dilatação pode causar danos estruturais irreversíveis. Por outro lado, dispositivos como sensores termostatos utilizados em equipamentos de aquecimento ou refrigeração, como ferros-de-passar e geladeiras, têm seu funcionamento baseado neste princípio físico. Os experimentos de ensino de física relacionados ao estudo da dilatação térmica de sólidos relatados na literatura utilizam diferentes tipos de aquecimento dos materiais estudados, mas a utilização de vapor d'água é a mais comum. Neste trabalho, está sendo proposta uma nova forma de aquecimento das amostras através de um forno elétrico que promove um aquecimento mais homogêneo, possibilitando resultados mais precisos, de forma mais rápida e de fácil visualização. O dispositivo foi construído com materiais de relativo baixo custo e de fácil aquisiçao. Os valores do coeficiente de dilatação térmica de diferentes materiais como alumínio, latão, cobre, cimento e vidro foram obtidos e mostraram um bom acordo quando comparados com os valores disponíveis na literatura.
Medición de frecuencias de resonancia, factor de pérdida y módulo de Young dinámico de varillas empotradas
Authors: Repetto C.E. , Roatta A. , Welti R.J.
Published: April 2014

En este trabajo se estudian teórica y experimentalmente las vibraciones forzadas de varillas rígidas y flexibles empotradas en un extremo. Las experiencias que se analizan, además de ilustrar el fenómeno de resonancia en una estructura diferente del clásico oscilador masa-resorte, permiten medir el módulo de Young del material. En el caso de la varilla flexible es fácil visualizar también el segundo y el tercer modo normal de vibración, lo cual nos permite comparar la forma que adopta la varilla, cuando vibra en sus diferentes modos, con las predicciones teóricas. En particular se pueden observar los "cuasi-nodos" (o nodos con pequeña amplitud) que se deben al flujo de energía a través de los mismos para compensar las pérdidas.
Investigando o impulso em crash tests utilizando vídeo-análise
Authors: Wrasse Ana Cláudia , Etcheverry Louise Patron , Marranghello Guilherme Frederico , Rocha Fábio Saraiva da
Published: April 2014

Utilizamos vídeos disponíveis na web que mostram testes de colisões de automóveis para investigar as propriedades do impulso de uma força. Este tema, pouco abordado em sala de aula, possui, em colisões de automóveis, uma possibilidade de aplicação em problemas reais e importantes para a compreensão de fenômenos presentes em nosso cotidiano. Segundo os PCN+, o dispositivo de airbag seria um excelente exemplo para ilustrar as propriedades do impulso. Para a investigação deste problema através de vídeos, utilizamos o software livre Tracker, onde determinamos propriedades físicas, tais como de posição, velocidade e aceleração, relacionadas ao movimento dos carros e manequins utilizados nos testes.
Ensinando física através do radioamadorismo
Authors: Bruscato Gentil César , Mors Paulo Machado
Published: April 2014

Em nossas escolas a relação ensino-aprendizagem, na maioria das vezes, restringe-se à tentativa de atingir o objetivo dos alunos obterem grau suficiente para serem aprovados no final do ano, sem haver maior preocupação com a aprendizagem significativa e contextualizada dos conteúdos ensinados, e com a interação social que promova a discussão dos assuntos estudados. Apresentamos uma proposta de ensino utilizando o radioamadorismo como tema motivador, em uma tentativa de melhor qualificar o aprendizado de física. Adotamos como referencial as teorias de aprendizagem significativa, de David Ausubel, e da interação social, de Lev Vygotsky. O projeto, a montagem de uma estação radioamadora para fins educacionais, em especial para o ensino da física, foi aplicado no segundo semestre de 2010, com a participação voluntária de alunos da série final do Ensino Fundamental e das três séries do nível médio do Colégio Militar de Porto Alegre, na modalidade ensino extracurricular, no contraturno do horário regular das aulas. É apresentado um relato da experiência e dos resultados alcançados, além de um texto-guia facilitador do professor que se interessar em reproduzir experiência semelhante.
La física en la extensión universitaria a través de la holografía como medio de educación social
Authors: Toledo Rolando Serra , Yeras Alfredo Moreno , Cruz Gilda Vega , Pérez Ibette Alfonso , Magalhães Daniel S.F. , Muramatsu Mikiya
Published: April 2014

Con el surgimiento de los hologramas reconstruibles con luz blanca y su desarrollo posterior, se abrieron grandes posibilidades para su utilización como medio de educación social por la característica de producir una imagen tridimensional que constituye un duplicado óptico de un objeto. En el trabajo se describen, la fundamentación y características del holograma como un medio de educación social y las experiencias en la construcción y utilización de exposiciones holográficas permanentes en museos e itinerantes en la comunidad como un resultado de extensión universitaria de las investigaciones físicas realizadas.
Stable isotopic composition of raw and treated water
Authors: Bieroza Magdalena , Baker Andy , Bridgeman John , Boomer Ian
Published: April 2014

To date, the δ18O and δ2H stable isotopic composition of freshwaters has received little attention compared to stable isotopes in precipitation. Specifically, studies characterising the stable isotopic variability of surface waters on regional and local scales are limited. Here, the δ18O and δ2H stable isotopic compositions of raw and partially treated waters from 16 UK water treatment works are examined. The water treatment works abstract surface waters from a range of catchments (upland versus lowland and semi-natural versus anthropogenically impacted). The investigation of stable isotope composition and deuterium excess (d-excess) revealed a high degree of spatial and temporal variability. Compared to rainfall, the spatial and temporal variability of surface water is more complex and catchment-dependent. Multiple linear regression analysis identified moderately strong relationships between catchment controls (altitude, mean rainfall, base flow index, aquifer permeability, location) and δ2H, δ18O and d-excess of raw and partially treated waters. Results suggest that catchment controls explain 60% (δ2H), 66% (δ18O) and 74% (d-excess) of the variation in isotopic composition of raw water. Results also indicate that catchment permeability has a stronger influence on surface waters isotopic composition than altitude, latitude or rainfall effects. The potential benefits from the use of isotopic composition data in the water supply are discussed.
Spatial and temporal variation in tree seed production and dispersal in a New Zealand temperate rainforest
Authors: Canham Charles D. , Ruscoe Wendy A. , Wright Elaine F. , Wilson Deborah J.
Published: April 2014

Spatial and temporal variation in tree seed production is an important driver of the population dynamics of trees and of mammalian and avian seed consumers. Many studies have documented strong synchrony in production of intermittent large tree seed crops (masting), with cascading effects on the food webs of seed consumers and their predators. We used inverse modeling to characterize spatial and temporal variation in seed production and dispersal by four dominant tree species (two angiosperms and two conifers) over 8 years in southern temperate rainforests of New Zealand. In contrast to expectations from masting theory, there was little evidence of synchrony across species in years of high seed production, and only weak evidence in support of the expectation that temporal variation in seed production within species was strongly bimodal. Contrary to expectation from allometric scaling rules, there was no increase in reproductive effort once tree size (DBH) exceeded a minimum threshold (22–29 cm DBH) in the two angiosperm species. In the conifers, the minimum estimated size threshold for seed production was much higher (42–56 cm DBH), and in one of the species increased faster than linearly with biomass above the threshold size, indicating that the very largest trees in the conifer populations dominated seed production. Of the two species that occurred commonly on both fertile alluvial sites and less fertile uplifted marine terraces, the angiosperm species had higher per capita seed production on the fertile sites, while the conifer had higher per capita seed production (during seed years) on the less fertile sites. Local seed rain from all four species declined steeply with increasing distance from a parent, with peak local dispersal within 6 m of parent trees. This is not surprising given that the species are predominately gravity or animal dispersed with poor adaptations for wind dispersal. A substantial fraction of the input of seeds of all four species could not be attributed to local parent trees, consistent with longer distance dispersal by animals.
Fluctuations of the number of adsorbed micro/nanoparticles in sensors for measurement of particle concentration in air and liquid environments
Authors: Jokic Ivana , Djuric Zoran , Radulovic Katarina , Frantlovic Milos
Published: April 2014

A theoretical model of fluctuations of the number of adsorbed
micro/nanoparticles in environmental sensors operating in air and liquids is
presented, taking into account the effects of the mass transfer processes of
the target particles in a sensor reaction chamber. The expressions for the
total power of the corresponding adsorption-desorption noise, and for the
corresponding signal-to-noise ratio are also derived. The presented analysis
shows that the transfer processes can have a significant influence on the
sensors limiting performance. The influence on both the fluctuations
spectrum and the signal-to-noise ratio is estimated at different values of
target particles concentration, functionalization sites surface density, and
adsorption and desorption rate constants (the values are chosen from the
ranges corresponding to real conditions). The analysis provides the
guidelines for optimization of sensor design and operating conditions for
the given target substance and sensor functionalization, in order to
decrease the influence of the mass transfer, thus improving the ultimate
performance (e.g. minimal detectable signal, signal-to-noise ratio) of
sensors for particle detection. The calculations we performed show that it
is possible to increase the signal-to-noise ratio for as much as two orders
of magnitude by using the optimization that eliminates the mass transfer
influence.
Thermal power of small scale manually fed boiler
Authors: Janic Todor , Igic Sasa , Dedovic Nebojsa , Pavlovic Darijan , Turan Jan , Sedlar Aleksandar
Published: April 2014

This study reviews test results of the combustion of square soybean straw
bales used as fuel in manually fed boiler with nominal thermal power of 120
kWth. The influence of the mass flow rate (180, 265, 350, 435, and 520 kg
h-1) of inlet air and flue gas recirculation (0%, 16.5%, and 33%) fed to the
boiler furnace was continuously monitored. Direct method was used for
determination of the boiler thermal power. Correlation between boiler thermal
power and bale residence time has been observed and simple empirical equation
has been derived. General conclusions are as follows: the increase of the
flow rate of inlet air passing through the boiler furnace results in decrease
of the bale residence time and increase of the boiler thermal power. Share of
the flue gas recirculation of 16.5% increases bale residence time and
decreases average boiler thermal power in all regimes except in the regime
with inlet air flow rate of 265 kg h-1. In regime with 0% flue gas
recirculation boiler thermal power was higher than nominal in regimes with
435 and 520 kg h-1 inlet air flow rates. In regimes having inlet air mass
flow rate of 350 kg h-1 boiler thermal power is equal to the nominal power of
120 kWth.
MHD two-phase fluid flow and heat transfer with partial slip in an inclined channel
Authors: Abbas Zaheer , Hasnain Jafar , Sajid Muhammad
Published: April 2014

The aim of this paper is to investigate the velocity and thermal slip effects
in MHD flow and heat transfer of two-phase viscous fluid. It is assumed that
both the phases have different densities, viscosities and electrical
conductivities. The fully developed flow governed by a constant pressure
gradient is passing through an inclined channel having inclination f with
horizontal axis. The electrical conductivity in phase I is assumed to be zero
so that the constant applied magnetic field of strength B0 in the transverse
direction only effect the fluid in phase II. The method of successive
approximation is used to develop the analytic solution of order 1 for the
developed dimensionless coupled ordinary differential equations. The main
focus is to discuss the influence of velocity and thermal slip parameters and
Hartmann number on the velocity and temperature profiles.
Numerical investigation of the effect of insulation on heat transfer of thermal bridges with different types
Authors: Karabulut Koray , Buyruk Ertan , Fertelli Ahmet
Published: April 2014

In the present study, the effects of different types thermal bridges formed
by beams for floor-wall junctions in reinforced concrete structures, with and
without balconies, and the optimum configuration of the insulation layers to
avoid heat loss were investigated as numerically. Both insulation between the
walls and internal insulation was selected for floor-wall junctions and
internal insulation was used for floor-wall junctions with balcony. Fluent
package program was used to solve the temperature domain numerically. Results
showed that high heat transfer rates were obtained in the region of thermal
bridges for all building models. It was also obviously obtained that heat
transfer rate decreased with making insulation on the beam surfaces.
Computational analysis of heat and mass transfer during microwave drying of timber
Authors: Kadem S. , Younsi R. , Lachemet A.
Published: April 2014

The need for improvement in engineering design and process optimization for
microwave drying of wood has stimulated the development of computer
simulation techniques to predict temperature and moisture history and
distribution wood sample. A three-dimensional comprehensive heat and mass
transfer model was developed to simulate the free liquid, vapor, and bound
water movement including consideration of internal heat generation in
microwave drying of yellow poplar specimens. The model was solved using the
finite element analysis with FEMLsoftware. The model predictions compared
favorably with predicted and experimental solutions. The effect of changes of
the most important parameters on the predictions of the model is also
presented. The results showed that the variations of irradiation time,
microwave power level and sample thickness played an important role in
overall drying kinetics.
Osteonecrosis of the jaw as a serious adverse effect of bisphosphonate therapy and its indistinct etiopathogenesis
Authors: Gavric Miodrag , Antic Svetlana , Jelovac Drago , Zarev Anita , Petrovic Milan , Golubovic Mileta , Antunovic Marija
Published: April 2014

nema
Histopathological Pattern of Salivary Gland Tumors
Authors: Shrestha S , Pandey GK , Pun CB , Bhatta R , Shahi R
Published: April 2014

Background: The tumors of the salivary glands are uncommon head and neck neoplasms. The aim of this study was to evaluate the relative frequencies, types, site distribution and the histopathological features of salivary gland tumors. Materials and Methods: This was a retrospective study of 176 cases of salivary gland tumors collected from medical record section and department of pathology at B.P.Koirala Memorial Cancer Hospital from Jan. 2005 to Dec. 2010. Tumors were analyzed based on demographics, anatomic location and histopathological type. Results: Out of 176 cases, 66 (37.5 %) were benign and 110 (62.5 %) were malignant with M:F ratio of 1.7:1. The mean age observed was 44.76 years with age range of 12 to 75 years. Pleomorphic adenoma was found to be the commonest benign tumor (72.7 %), followed by Warthin tumor (15.1%), monomorphic adenoma (3.0 %) and basal cell adenoma (3.0 %). The mucoepidermoid carcinoma was the most common malignant tumor (38.1 %), followed by adenoid cystic carcinoma (25.4%), acinic cell carcinoma (10.9%), adenocarcinoma NOS (6.3%), carcinoma ex pleomorphic adenoma (5.4%) and unclassified malignant tumor (4.5 %). Parotid was the most common site for the location of tumors (70.4%) followed by submandibular (19.3%) and minor salivary glands (10.2 %). Conclusion: Pleomorphic adenoma was the commonest salivary gland tumor observed in both sexes. Mucoepidermoid carcinoma was the most common malignant salivary gland tumor. The parotid gland was the most common site of origin in both benign and malignant tumors. DOI: http://dx.doi.org/10.3126/jpn.v4i7.10291 Journal of Pathology of Nepal (2014) Vol. 4, 520-524