2,907 research outputs found

    Dedifferentiation and growth of friable calluses from stems of Capsicum chinense cv. Airetama.

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    Chili peppers belong to the genus Capsicum and have been studied for their bioactivity, provided by secondary metabolites, which can be used for medicinal and agricultural purposes. Some Capsicum species have been submitted to in vitro cultivation systems of cell suspensions, which have been largely reported as safe and standardized methods of production of secondary compounds. The objective of this study was to determine a protocol for the establishment of cell suspensions from stems of the cultivar C. chinense cv. Airetama. For this, it was necessary to determine the combinations and concentrations of growth regulators for callus induction and to study the growth pattern of the calluses with a focus on the deceleration phase. In this phase the callus cells must be subcultured in a liquid medium in order to establish cell suspension cultivations. Stem explants were inoculated into media supplemented with 2,4-D and BA. The proliferation of callus cells and their growth pattern were evaluated. The highest callus cell proliferation occurred with the combination of 18.10 µM 2,4-D + 2.22 µM BA. The calluses were friable and whitish and their growth pattern followed a sigmoid shape. The deceleration phase started on the 42nd day

    Portuguese airport efficiency analysis: the case study of Oporto

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    The Oporto Airport located in the northern region in Porto city is crucial because is the only one located in the northern region. This airport had an increasing in number of passengers, sales revenue and accumulated investment during the last two decades, principally after the introduction and the operation of the Low Cost Companies since 2004 to the present. In order to determine if the last changes had an impact in the competitiveness of this airport, the main aims is to analise the evolution of values of the technical efficiency and equate the results before and after the introduction of the LCCs in this airport. The methodology uses the Data Envelopment Analysis. Results show that the Oporto Airport efficiency increases highly after the introduction of LCCs since 2004. The main conclusions suggest the importance of the introduction of LCCs in the increasing efficiency of the Oporto Airport and the potential relation with tourism development in this region, but more strong studies are needed.info:eu-repo/semantics/publishedVersio

    Simulation of Offshore Wind System with Three-Level Converters: HVDC Power Transmission in Cloud Scope

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    This paper is on a simulation for offshore wind systems in deep water under cloud scope. The system is equipped with a permanent magnet synchronous generator and a full-power three-level converter, converting the electric energy at variable frequency in one at constant frequency. The control strategies for the three-level are based on proportional integral controllers. The electric energy is injected through a HVDC transmission submarine cable into the grid. The drive train is modeled by a three-mass model taking into account the resistant stiffness torque, structure and tower in the deep water due to the moving surface elevation. Conclusions are taken on the influence of the moving surface on the energy conversion

    Distribution and provenance of heavy minerals from recent sediments of Green Lake, North Brazil, revisited

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    Geostatistical and multivariate statistical analyses were applied to heavy mineral data from an Amazonian fluvial-lake system near the Tapajós River mouth to investigate the spatial distribution and source-area of sediments. Twenty-one points were investigated, and the physical characteristics of the Green Lake deepest point were determined. Sand accumulates in the lake margins and mud quantity increases towards the lake center. Heavy mineral assemblage is composed of zircon, tourmaline, kyanite, rutile, staurolite, anatase, sillimanite, garnet, and spinel. Tourmaline, staurolite, and spinel are more abundant in the southeast area of the lake, while kyanite is dominant in the north area and zircon is in the whole lake except in its southeast area. Zircon - tourmaline and zircon - staurolite pairs are negatively correlated (r= -0.947 and -0.775, respectively), while tourmaline - staurolite and sillimanite - anatase pairs have a positive correlation (r= 0.628 and 0.675, respectively) which indicate different source rock types. Geostatistical analysis grouped the heavy minerals in three grups: Group 1 (tourmaline – staurolite – spinel - kyanite) and Group 2 (garnet – rutile – sillimanite - anatase) related to metamorphic source rocks ranging from medium to high grade, and Group 3 (zircon) related to acid igneous source rocks. The heavy mineral assemblage of Green Lake is analogous to the assemblage of the Alter do Chão Formation, indicating that this formation is the source of sediments of Green Lake

    Influence of preparation procedures on the phenolic content, antioxidant and antidiabetic activities of green and black teas

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    The influence of common tea preparation procedures (temperature, infusion time, consumption time interval and tea bag/loose-leaf) and the type of water used, on the total phenolic content (TPC), the radical scavenging activity and the alpha-glucosidase inhibitory activity were assessed. Higher TPC and antioxidant activity were obtained when using lower mineralized waters. Tea bags also evidenced higher antioxidant activity than loose-leaf samples. Under the same conditions (90 degrees C and five minutes of infusion time) green tea contains almost twice the quantity of polyphenols and the free radical scavenging ability of black tea. In the alpha-glucosidase assay all infusions were active (97-100 %). Furthermore, HPLC allowed to identify some of the polyphenols present in both teas and to monitor their composition change with time. After twenty-four hours, the antioxidant activity was maintained without significant changes, but a small decrease in enzyme inhibition was observed, although this activity was still very high.info:eu-repo/semantics/publishedVersio

    Utilização de obras protegidas pelo direito autoral em Website de conteúdo: a experiência da Embrapa Informática Agropecuária.

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    O artigo relata a experiência de adoção de mecanismo de proteção de direito autoral em website de conteúdo "Agência de Informação Embrapa da Cana-de-açúcar", na Embrapa. Para todas as obras utilizadas como fonte de produção do conteúdo do website, foram solicitadas autorizações de uso de autores. Uma licença de uso de obras foi celebrada entre a Embrapa e os autores, com triplo objetivo: o estrito cumprimento do diploma legal de direitos autorais (lei 9.610/1998), o reconhecimento e proteção dos direitos dos autores das obras e a salvaguarda da empresa de possíveis ações judiciais por violação de propriedade intelectual.XXIII CBBD

    MULTI-FIELD STABILIZED FINITE ELEMENT APPROXIMATIONS FOR OLDROYD-B FLUID FLOWS

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    This work concerns with numerical simulations of creeping and inertial flows of viscoelastic fluids. The mechanical model consists of mass and momentum balance equations, coupled with the Oldroyd-B fluid. The model is approximated by a multi-field Galerkin least-squares (GLS) methodology in terms of extra-stress, velocity and pressure. The GLS method, introduced by Hughes et al. (1986) in the context of the Stokes problem for Newtonian fluidflows, allows the use of combinations of equal-order finite element interpolations and remains stable even for elastic- and inertiadominated fluid flows. Some steady simulations of Oldroyd-B fluids, flowing over a slot, are herein carried out. The influence of inertia and fluid viscoelasticity is taken into account ranging the Reynolds and Weissenberg numbers for relevant values of this flow. The results are in accordance to the viscoelastic literature and reassure the fine stability features of the GLS formulation

    Resposta das bananeiras Grand Naine e Princesa a irrigação no segundo ciclo nas condições do Norte de Minas.

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    A bananeira é uma das fruteiras mais exploradas nos países tropicais e seu fruto um dos mais consumidos no mundo. O Brasil ocupa a quarta posição no ranking dos países produtores de banana, com cerca de 7 milhões de toneladas de frutos produzidos em 2008 (AGRIANUAL, 2011). A bananeira é uma planta herbácea de rápido crescimento e de grande porte, que chega a produzir mais de 300 toneladas de matéria fresca por hectare, por safra (LICHTEMBERG; LICHTEMBERG, 2011), sendo a massa de água correspondente a 87,5% da massa total da planta. Desta forma é uma cultura que consome grandes volumes de água
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