191 resultados para Goma arábica


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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The objective of this work was to evaluate the productive and economic performance of Arabica coffee and macadamia nut intercropping, under rainfed and drip-irrigation conditions, as well as the financial viability of treatments in three coffee price scenarios. A completely randomized design was used, with six treatments (rainfed sole coffee, irrigated sole coffee, rainfed coffee-macadamia nut intercropping, irrigated coffee-macadamia nut intercropping, rainfed sole macadamia nut, and irrigated sole macadamia nut) and ten replicates. The productivity, the area equivalency index, and the economic outcomes of the treatments were evaluated in three coffee price scenarios. Drip irrigation and intercropping increased coffee and macadamia nut yields, in comparison to rainfed monocultures, and generally promoted the same productivity as the coffee irrigated monocultures, as well as higher productivity than the macadamia nut irrigated monocultures. The combined use of intercropping and drip irrigation promotes land-use efficiency 5-fold greater than the averages of rainfed monocultures. Irrigated intercropping promotes higher profitability and faster return on investment, making it a viable alternative, especially in periods of lower coffee prices.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Pós-graduação em Ciência e Tecnologia Animal - FEIS

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Os mercados futuros possuem uso restrito entre os cafeicultores brasileiros, o que, de certa maneira, não condiz com as altas razões ótimas de hedge obtidas nos modelos de mínima variância. Os motivos para esta baixa utilização estão associados às características do produtor e de seu negócio, preferências em relação ao modelo de administração de risco da atividade e questões comportamentais. Diante disso, o presente estudo buscou verificar quais fatores interferem na decisão de uso destes derivativos entre os cafeicultores brasileiros. Em uma primeira etapa, foram calculadas razões ótimas de hedge, de acordo com Myers e Thompson (1989), para os mercados da BM&FBOVESPA e ICE Futures. Tais razões apresentaram valores superiores a 50%. Em uma segunda etapa, a partir da aplicação de 373 questionários, observou-se que 12,9% da amostra declara conhecer e utilizar futuros, sendo que, na média, a razão de hedge adotada esteve abaixo de 50%. Em uma terceira etapa, a partir de um modelo logit, concluiu-se que os fatores que influenciaram o uso dos contratos foram grau de aversão ao risco de preço, tamanho da produção, nível de conhecimento sobre derivativos e dimensão pela qual se entende que tais instrumentos levam à maior estabilidade da receita da atividade.

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O aumento das doses de potássio (K) para atender a demanda nutricional desse nutriente em cafezais produtivos induz a deficiência de Mg. Esta pesquisa foi realizada com o objetivo de compreender como a classe de solo interfere na interação entre esses nutrientes (K e Mg), de maneira que a aplicação de alta dose de K não afete a nutrição da planta em relação ao Mg. Dois experimentos foram conduzidos em duas classes de solo: Latossolo, com textura muito argilosa, em Machado-MG, e Argissolo, com textura media sobre argilosa, em Monte Santo de Minas-MG. Adotou-se delineamento fatorial com três doses de K (110, 260 e 390 kg ha-1 K2O) x cinco doses de Mg (0, 81, 162, 324 e 405 kg ha-1 MgO), com três repetições. No Argissolo, a lixiviação de K impediu a redução da concentração foliar de Mg, independentemente da dose de K. No Latossolo, a concentração de Mg foliar variou com a dose de K, e apresentou ajuste quadrático. A concentração foliar de Mg aumentou linearmente com a dose desse nutriente, independentemente da classe de solo e da dose de K.

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Dissertação para obtenção do grau de Mestre no Instituto Superior de Ciências da Saúde Egas Moniz

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At head of title: Oficina Nacional de Inmigracion, Estadística y Propaganda Geográfica.

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In double columns.

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Mode of access: Internet.

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The written text, and approaches to reading it, serves well as an analogy for the classroom space as a "text" that teachers are able to compose; and students are able to read, interpret meaning(s) of, and make responses to and about (Rosenblatt, 1988). Researchers point to ways in which the classroom can be conceptualized as a text to be evoked, experienced, and read (Freire & Macedo, 1987; Powell, 2009; Rosenblatt, 1988; Spears-Bunton & Powell, 2009).^ The present study analyzed secondary data including: 10 transcripts of teacher talks and six self-reports retrieved from the program evaluation archives of DOR Foundation. The data described six teachers' classroom experiences subsequent to professional development centered on Goma character education curriculum that was used during a summer youth program located in South Georgia. Goma, an acronym that stands for Goal, Objective, Method, and Attitude, is a character education paradigm derived from The Inclusive Community Building Ellison Model, the theoretical framework used for this study. The Model identifies conflict resolution as one of its five foci (Hunt, Howard, & Rice, 1998). Hunt (2006) conceived Goma as part of a 7-Step unitary process, also named the 7-Step pathway, to demonstrate how conflict resolution is accomplished within a variety of contexts.^ Analysis of the data involved: (a) a priori coding of teacher talks transcripts using the components of the Goma 7-Step pathway as coding categories, (b) emergent coding of teacher talks transcripts for the types of experiences teachers evidenced, and (c) emergent coding of teachers' self-reports for categories of teachers' instructional activities. Results of the study showed positive influence of Goma curriculum on participating teachers and their instructional practices. Teachers were shown to have had cognitive, instructional, emotional, and social experiences that were most evident when they reported changes in their attitudes toward their students, themselves, and their instructional practices. The present study provided implications for classroom teachers wherein all aspects of teachers' instructional practices can be guided by principles of positive character; and can be used to help compose the kinds of "texts" that may likely contribute to a classroom character culture.^

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This study aimed mainly to evaluate the influence of xanthan gum (XG) and carboxymethylcellulose (CMC) in the filtration process of water-based drilling fluids, considering the conformational changes suffered by the polyelectrolyte with the addition of sodium chloride (NaCl) in different concentrations (0.17, 0.34 and 0.51 mol.L-1). It was also evaluated the behavior of the fluid by the addition of calcium carbonate (CaCO3) in pure water and in brine. Seeking a better understanding of the interaction between the polymers used and CaCO3, polymer adsorption analyzes were performed using a depletion method, which yielded a higher percentage of adsorption of Xanthan Gum in this material (29%), which can justify the formation of a thin and waterproof filter cake for drilling fluids containing this polymer. However, the best values of apparent viscosity (20 and 24 mPa.s) and volume of filtrate (8.0 and 8.1 mL) were obtained for the systems consisting of xanthan gum, CMC and CaCO3, in NaCl aqueous solutions concentrations of 0.34 and 0.51 mol.L-1, respectively. The values can be related to the presence of CMC that increases the apparent viscosity and reduces the volume of filtrate. In addition, the CaCO3 added acts as a bridging agent, promoting the formation of a less permeable filter cake

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Produced water is considered the main effluent of the oil industry, due to their increased volume in mature fields and its varied composition. The oil and grease content (TOG) is the main parameter for the final disposal of produced water. In this context, it is of great significance to develop an alternative method based on guar gum gel for the treatment of synthetic produced water, and using as the differential a polymer having high hydrophilicity for clarifying waters contaminated with oil. Thus, this study aims to evaluate the efficiency of guar gum gels in the remotion of oil from produced water. Guar gum is a natural polymer that, under specific conditions, forms three-dimensional structures, with important physical and chemical properties. By crosslinking the polymer chains by borate ions in the presence of salts, the effect salting out occurs, reducing the solubility of the polymer gel in water. As a result, there is phase separation with the oil trapped in the collapsed gel. The TOG was quantified from the spectroscopy in the ultraviolet and visible region. The system was proven to be highly efficient in the removal of dispersed oil from water produced synthetically, reaching removal percentages above 90%.

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Oral route of administration is considered to be the most comfortable, safe and greater adaptation for patients. But, oral route presents some disadvantages such as drugs bioavailability and side effects on the stomach. Some technologies are studied to soften and/or resolve these problems, such as coating with polymeric films, which are able to protect the pharmaceutical form of the acid stomachic environment and to act in the drug release, and mucoadhesive systems, which allow the pharmaceutical form remains a greater time interval in the intestine, increasing the effectiveness of the drug. Cellulose triacetate (CTA) films were produced from cellulose extracted from sugar cane bagasse. The films were prepared with different morphologies (with and without water, acting as non-solvent) and concentrations (3, 6.5 and 10%) of CTA and characterized using scanning electron microscopy (SEM), water vapor permeability (WVP), puncture resistance (PR), enzymatic digestion (DE), and mucoadhesive force evaluation (MF). Microscopy showed the formation of symmetric and asymmetric morphologies. WVP data showed that more concentrated films have higher values for WVP; moreover, asymmetric films had higher values than symmetric films. PR measurements showed that symmetric membranes are more resistant than asymmetric ones. More concentrated films were also more puncture resistant, except for symmetric membranes with CTA concentrations of 6.5 and 10% that did not show significant differences. All of the films presented large mucoadhesive capacities independent of their morphology and CTA concentration. From the results of WVP and RP, a symmetric filme with 6.5% CTA showed better ability and mechanical resistance, therefore, was selected to serve as coating of gellan gum (GG) particles incorporating ketoprofen (KET), which was confirmed by SEM. The selected film presented low values in measurements of the swelling index (SI) and in a dissolution test (DT). TGA analysis showed that the CTA coating does not influence the thermal stability of the particles and there is no incompatibility evidence between CTA, GG and KET. Coated particles released 100% of the ketoprofen in 24 h, while uncoated particles released the same amount in 4 h. The results of this study highlight the potential of CTA in the development of new controlled oral delivery systems.