يعرض 1 - 10 نتائج من 419 نتيجة بحث عن '"Oliveira, José Eduardo"', وقت الاستعلام: 0.75s تنقيح النتائج
  1. 1
    دورية أكاديمية
  2. 2
    دورية أكاديمية

    المصدر: Pesquisa Agropecuária Tropical. March 2015 45(1)

    الوصف: A produção de acerola pode aumentar consideravelmente, quando suas flores são visitadas por abelhas. Este estudo objetivou determinar o grau de dependência da aceroleira cultivar Olivier, em relação à polinização entomófila, bem como conhecer seus polinizadores potenciais, por meio de análise das características florais e do comportamento da entomofauna visitante. Os insetos mais frequentes foram: Centris (Centris) varia (43,9 %), Centris (Centris) decolorata (17,4 %), Centris(Centris) flavifrons (15,6 %), Epicharis (Epicharana) flava (7,6 %), Centris (Centris) nitens (5,9 %), Centris (Hemisiella) tarsata (4,9 %), Tetragonisca angustula (2,5 %) e Trigona spinipes (2,3 %). Foi observado que as abelhas dos gêneros Centris e Epicharis coletaram óleo, enquanto as T. angustula coletaram pólen e as T. spinipes cortaram as flores. A frutificação foi maior quando as flores estavam abertas à polinização (27 % de frutos gerados), seguida de polinização manual cruzada (11 %) e polinização restrita (1 %). Não houve formação de frutos por meio de autopolinização. A cultivar Oliver demonstrou alta dependência da polinização entomófila, sendo que abelhas Centris e E. flavapodem realizar tal serviço eficientemente.

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  3. 3
    دورية أكاديمية

    المصدر: Matéria (Rio de Janeiro). September 2014 19(3)

    الوصف: O cálculo da incerteza de medição em ensaios mecânicos é uma etapa primordial para a garantia da confiabilidade dos resultados apresentados. Porém, mesmo atribuindo-se um cálculo estatístico, não necessariamente se obterá um resultado realístico, por não se considerar, muitas vezes, todas as variáveis que contribuem significativamente para a incerteza de medição e por não se considerar o efeito da correlação entre variáveis quando ele se apresenta. Dentro deste contexto, o objetivo deste trabalho é realizar um estudo analítico da influência do coeficiente de correlação no cálculo da incerteza de medição da tensão limite de resistência mecânica, obtido através do ensaio de tração. No estudo experimental, variou-se o número de corpos de prova para a obtenção dos diferentes valores de coeficiente de correlação, com o intuito de se calcular a incerteza de medição considerando-se as grandezas correlacionadas e a incerteza de medição desprezando esse efeito. Através deste estudo foi possível se verificar o quanto a correlação entre a variação da força máxima e a variação do diâmetro da parte reduzida do corpo de prova pode influenciar o resultado da medição, além de apresentar a maneira correta de se calcular a incerteza padronizada combinada considerando a correlação.

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  4. 4
    دورية أكاديمية

    المصدر: Revista de Odontologia da UNESP. August 2013 42(4)

    مصطلحات موضوعية: Glass ionomer cements, inorganic chemicals

    الوصف: INTRODUCTION: Glass ionomer cements (GICs) release inorganic elements and organic residual monomers with the potential for deleterious effects on pulp cells. OBJECTIVE: To identify and quantify inorganic elements present in different GICs and released components from these materials in cell culture medium. MATERIAL AND METHOD: Samples of two resin-modified GICs for base/liner (Vitrebond and Fuji Lining LC), two resin-modified restorative GICs (Vitremer and Fuji II LC) and two conventional restorative GICs (Ketac Fil Plus and Ketac Molar Easymix) were prepared and analyzed by Energy-Dispersive X-Ray Fluorescence Spectrometry (EDXRF). Extracts of these materials were obtained by immersion of each sample in separate containers of DMEM for 24 h (total surface-liquid ratio = 45.7 mm²/mL). The extracts were analyzed by EDXRF and Gas Chromatography-Mass Spectrometry (GC-MS). RESULT: Higher percentages of strontium, silicon and aluminum were identified in Vitrebond, Vitremer, Fuji Lining LC, Fuji II LC, and Ketac Fil Plus, while zinc was detected only in Vitrebond. Ketac Molar Easymix presented a greater atomic composition of lanthanum, calcium, aluminum and silicon. Strontium was detected in the extracts from all materials except Ketac Molar Easymix; calcium was present in extracts from Ketac Fil Plus; zinc only in Vitrebond; and silicon in Fuji II LC extract. The analysis by GC-MS detected 2-hydroxyethyl-methacrylate (HEMA) in the extracts from all resin-modified GICs, and iodine benzene was detected only in the Vitrebond extract. CONCLUSION: Of the GICs sampled, Vitrebond released the highest number of components with cytotoxic potential.

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  5. 5
    دورية أكاديمية

    المصدر: Pesquisa Agropecuária Tropical. June 2013 43(2)

    الوصف: A sericicultura é uma atividade que apresenta a possibilidade de obtenção de renda em áreas inferiores a 10,0 ha, bem como a racionalização da mão de obra familiar. Mesmo considerando-se este cenário favorável ao desenvolvimento desta atividade, ainda existe uma lacuna no gerenciamento dos seus fatores econômicos, em grande parte das propriedades rurais inseridas nesta cadeia, contribuindo, negativamente, para a sua expansão. Objetivou-se avaliar o custo de produção e a viabilidade econômica para a produção de casulos, por meio de estudo de caso realizado em uma propriedade no município de Quatá (SP). Os principais resultados para uma produção de 1.904 kg ano-1 de casulos, dado que as despesas com mão de obra perfizeram 51,5% do Custo Operacional Efetivo e 35,5% do Custo Operacional Total, foram Índice de Lucratividade superior a 50% e Taxa Interna de Retorno de 9,68%, já para o segundo ano produtivo, proporcionando boa rentabilidade para este segmento agropecuário, considerando-se que a melhoria na rentabilidade do produtor é proporcional aos melhores indicadores de produção, sobretudo pelo rápido retorno que a atividade proporciona.

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  6. 6
    دورية أكاديمية

    المصدر: Journal of the Brazilian Chemical Society. April 2013 24(4)

    مصطلحات موضوعية: strontium oxide, biodiesel, heterogeneous catalysis

    الوصف: This work describes the preparation of babassu, castor oil biodiesel and mixtures in various proportions of these oils, using alkaline compounds of strontium (SrCO3 + SrO + Sr (OH)2) as heterogeneous catalysts. The mixture of oils of these oleaginous sources was used in the production of biodiesel with quality parameters that meet current legislation. The catalyst was characterized by X-ray diffractometry (XDR), physisorption of gas (BET method), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDX) and Fourier transform infrared spectroscopy (FTIR). The viscometric technique was used to monitor the optimization. The transesterification reactions performed using strontium compounds reached conversion rates of 97.2% babassu biodiesel (BB), 96.4% castor oil biodiesel (COB) and 95.3% Babassu/Castor Oil Biodiesel 4:1 (BBCO41).

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  7. 7
    دورية أكاديمية

    المصدر: Revista Brasileira de Farmacognosia. June 2011 21(3)

    الوصف: Cytotoxic activity of eight plant extracts, native from the Mid-West of Brazil comprising Cerrado, Pantanal and semideciduous forest, was evaluated for MDA-MB-435, SF-295, and HCT-8 cancer cell strains. A single 100 µg.mL-1 dose of each extract was employed with 72 h of incubation for all tests. Doxorubicin (1 µg.mL-1) was used as the positive control and the MTT method was used to detect the activity. Cytotoxicity of distinct polarities was observed in thirty extracts (46%), from different parts of the following species: Tabebuia heptaphylla (Vell.) Toledo, Bignoniaceae, Tapirira guianensis Aubl., Anacardiaceae, Myracrodruon urundeuva Allemão, Anacardiaceae, Schinus terebinthifolius Raddi, Anacardiaceae, Gomphrena elegans Mart., Amaranthaceae, Attalea phalerata Mart. ex Spreng., Arecaceae, Eugenia uniflora L., Myrtaceae, and Annona dioica A. St.-Hil., Annonaceae. Extracts of at least two tested cell strains were considered to be highly active since their inhibition rate was over 75%.

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  8. 8
    دورية أكاديمية

    المصدر: Química Nova. January 2010 33(10)

    الوصف: Since the introduction of GC there has been an ongoing interest in reducing time of analysis resulting in new terms and definitions such as ultra fast gas chromatography (UF-GC). One of the most used definitions describes UF-GC as a technique that combines the employment of short narrow bore column with very fast temperature programming rates producing chromatographic peaks in the range of 50 ms and allowing separations times in 1-2 min or less. This paper summarizes the analytical approaches, the main parameters involved and the instrumentation towards UF-GC.

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  9. 9
    دورية أكاديمية

    المصدر: Química Nova. January 2009 32(1)

    مصطلحات موضوعية: BTEX, gasoline, statistical analysis

    الوصف: Automotive gasoline consists of a complex mixture of flammable and volatile hydrocarbons derived from crude oil with carbon numbers within the range of 4-12 and boiling points range of 30-225 ºC. Its composition varies with the kind of crude oil and the type of refinery process that they undergone. Aromatics hydrocarbons, in particular benzene, toluene, ethylbenzene and isomeric xylenes (BTEX) are the toxic group constituents presents. GC-FID was employed to quantify these hydrocarbons in 50 commercial gasoline samples from Piauí state. Statistical analysis techniques, such as PCA and HCA were used to analyze the data. Moreover, several validation parameters were evaluated.

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  10. 10
    دورية أكاديمية

    المصدر: Psychology & Neuroscience. December 2008 1(2)

    الوصف: Iron deficiency alters metabolism, neurotransmission, glial integrity and the cortical myelin layer, besides increasing myelinization time. Environmental stimulation (handling) improves morphological, biochemical, electrophysiological and behavioral aspects of both well-nourished and malnourished animals. The objective of the present study was to determine the effects of an irondeficient diet and of handling on the brainstem auditory evoked potential (BAEP) of rats during development. Ninety-six male rats were divided since birth into Well-nourished (W, 35 mg iron/kg) and Anemic (A, 4 mg iron/kg) groups, and subdivided into Handling (H) and No Handling (NH). Body weight, hemoglobin (Hb), hematocrit (Ht), latencies of waves I, II, III IV, I-IV interpeak interval, and response threshold to auditory stimuli were evaluated at 18, 22, and 32 days. W animals presented higher Hb and Ht levels than A animals at 18, 22 and 32 days. The animals presented longer latencies of waves I, II, III and IV and I-IV interpeak interval of BAEP at 18 than at 22 and 32 days, and AH18 rats presented longer latencies of waves I and II than AH22 and AH32 rats, and longer wave I latency than WH18 animals. Iron deficiency increased the latencies of BAEP waves, suggesting damage to the myelin layer, especially during the early development, and the effects of handling were more evident along time in anemic animals.

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