576 research outputs found

    Influences of thermal environment on fish growth

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    Indexación: Scopus.Thermoregulation in ectothermic animals is influenced by the ability to effectively respond to thermal variations. While it is known that ectotherms are affected by thermal changes, it remains unknown whether physiological and/or metabolic traits are impacted by modifications to the thermal environment. Our research provides key evidence that fish ectotherms are highly influenced by thermal variability during development, which leads to important modifications at several metabolic levels (e.g., growth trajectories, microstructural alterations, muscle injuries, and molecular mechanisms). In Atlantic salmon (Salmo salar), a wide thermal range (ΔT 6.4°C) during development (posthatch larvae to juveniles) was associated with increases in key thermal performance measures for survival and growth trajectory. Other metabolic traits were also significantly influenced, such as size, muscle cellularity, and molecular growth regulators possibly affected by adaptive processes. In contrast, a restricted thermal range (ΔT 1.4°C) was detrimental to growth, survival, and cellular microstructure as muscle growth could not keep pace with increased metabolic demands. These findings provide a possible basic explanation for the effects of thermal environment during growth. In conclusion, our results highlight the key role of thermal range amplitude on survival and on interactions with major metabolism-regulating processes that have positive adaptive effects for organisms.http://onlinelibrary.wiley.com/doi/10.1002/ece3.3239/ful

    Normas técnicas e documentos de acompanhamento da produção Integrada de maçã- 2º versão.

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    bitstream/item/60750/1/CNPUV-DOC.33-04.pdf2. ed

    Optical Sky Brightness at Cerro Tololo Inter-American Observatory from 1992 to 2006

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    We present optical UBVRI sky brightness measures from 1992 through 2006. The data are based on CCD imagery obtained with the CTIO 0.9-m, 1.3-m, and 1.5-m telescopes. The B- and V-band data are in reasonable agreement with measurements previously made at Mauna Kea, though on the basis of a small number of images per year there are discrepancies for the years 1992 through 1994. Our CCD-based data are not significantly different than values obtained at Cerro Paranal. We find that the yearly averages of V-band sky brightness are best correlated with the 10.7-cm solar flux taken 5 days prior to the sky brightness measures. This implies an average speed of 350 km/sec for the solar wind. While we can measure an enhancement of the night sky levels over La Serena 10 degrees above the horizon, at elevation angles above 45 degrees we find no evidence that the night sky brightness at Cerro Tololo is affected by artificial light of nearby towns and cities.Comment: 24 pages, 5 figures, to be published in the June, 2007, issue of the Publications of the Astron. Society of the Pacifi

    Use of images of leaves and fruits of apple trees for automatic identification of symptoms of diseases and nutritional disorders.

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    Rapid diagnosis ofsymptoms caused by pest attack, diseases and nutritional or physiological disorders in apple orchards is essential to avoid greater losses. This paper aimed to evaluate the efficiency of Convolutional Neural Networks (CNN) to automatically detect and classify symptoms of diseases, nutritional deficiencies and damage caused by herbicides in apple trees from images of their leaves and fruits. A novel data set was developed containing labeled examples consisting of approximately 10,000 images of leaves and apple fruits divided into 12 classes, which were classified by algorithms of machine learning, with emphasis on models of deep learning. The resultsshowed trained CNNs can overcome the performance of experts and other algorithms of machine learning in the classification of symptoms in apple trees from leaves images, with an accuracy of 97.3% and obtain 91.1% accuracy with fruit images. In this way, the use of Convolutional Neural Networks may enable the diagnosis of symptoms in apple trees in a fast, precise and usual way. Keywords Apple, Apple Disorders, Artificial Intelligence, Automatic Disease Identification, Classifications, Convolutional Neural Networks, Disorders, Machine Learnin

    The core population and kinematics of a massive clump at early stages: an ALMA view

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    High-mass star formation theories make distinct predictions on the properties of the prestellar seeds of high-mass stars. Observations of the early stages of high-mass star formation can provide crucial constraints, but they are challenging and scarce. We investigate the properties of the prestellar core population embedded in the high-mass clump AGAL014.492-00.139, and we study the kinematics at the clump and the clump-to-core scales. We have analysed an extensive dataset acquired with the ALMA interferometer. Applying a dendrogram analysis to the Band o-H2D+\rm H_2D^+ data, we identified 22 cores. We have fitted their average spectra in local-thermodinamic-equilibrium conditions, and we analysed their continuum emission at 0.8mm0.8 \, \rm mm. The cores have transonic to mildly supersonic turbulence levels and appear mostly low-mass, with Mcore<30MM_\mathrm{core}< 30 \, \rm M_\odot. Furthermore, we have analysed Band 3 observations of the N2H+\rm N_2H^+ (1-0) transition, which traces the large scale gas kinematics. Using a friend-of-friend algorithm, we identify four main velocity coherent structures, all of which are associated with prestellar and protostellar cores. One of them presents a filament-like structure, and our observations could be consistent with mass accretion towards one of the protostars. In this case, we estimate a mass accretion rate of M˙acc2×104Myr1 \dot{M}_\mathrm{acc}\approx 2 \times 10^{-4} \rm \, M_\odot \, yr^{-1}. Our results support a clump-fed accretion scenario in the targeted source. The cores in prestellar stage are essentially low-mass, and they appear subvirial and gravitationally bound, unless further support is available for instance due to magnetic fields.Comment: Accepted for publication in Ap

    Produção de inóculo de Trichoderma viride para o controle da armilariose em Pinus spp.

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    Organizado por Patricia Póvoa de Mattos, Celso Garcia Auer, Rejane Stumpf Sberze, Katia Regina Pichelli e Paulo César Botosso

    Hidrólisis del aceite de coco (Cocos nucífera L) mediante enzimas estereoespecíficas y sin especificidad posicional.

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    The characteristic fatty acid composition of coconut oil provides mainly short- and medium- chain fatty acids when incorporated to the diet. These fatty acids have nutritional advantages because their metabolic disposition allows the rapid obtention of energy, mainly at the hepatic level. The obtention of short- and medium- chain fatty acids from coconut oil as substrate, may be of importance because the different nutritional, pharmacological, and technological uses of these fatty acids. In the present work, the effect of two type of lipases on the hydrolysis of coconut oil was studied; a lipase obtained from Candida cylindracea showing no positional specificity, and a lipase from Mucor miehei with sn-1',3' specificity in its free and immobilized form (Lipozyme IM-20). The lipase from Candida cylindracea allows the hydrolysis of 85%-90% of the triacylglycerols after 47-50 hours, the fatty acid composition of the hydrolyzate being similar to the composition of the oil. The remaining monoacylglycerols show a prevalent composition of short- (C6-C8) -and medium- chain (C10-C14) fatty acids. Lipase from Mucor miehei allows 65% of hydrolysis, which is obtained after 30 hours of incubation when the free form of the lipase is assayed, and after 10 hours for the immobilized form (Lipozyme IM-20). The fatty acid composition of the hydrolyzate is similar for the two enzymes and different to the composition of the oil, being C8-C14 the most prevalent fatty acids. The remaining monoacylglycerol, as product of the action of both forms of the enzyme, is almost enterely composed by lauric acid (C12:0), implicating that the sn-2' position is the most favoured for this fatty acid in the coconut oil triacylglycerols. The usefulness of lipases for the obtention of especific fractions of some fatty acids is discussed. The utility of the lipase from Mucor miehei for the obtention enriched fractions of lauric acid, which can be liberated after saponification, is also discussed.El aceite de coco, por su composición, aporta a la dieta principalmente ácidos grasos de cadena corta y media, los que desde el punto de vista nutricional tienen ventajas, debido a su rápida utilización metabólica que permite brindar energía, principalmente a nivel hepático. Es importante contar con procedimientos que permitan obtener estos ácidos grasos en forma libre a partir del aceite de coco, ya que de esta manera pueden ser utilizados con diferentes fines, ya sea nutricionales, farmacológicos o tecnológicos. En el presente trabajo se estudió la hidrólisis del aceite de coco producida por dos tipos de lipasas; una lipasa sin especificidad posicional obtenida de Candida cylindracea, y otra lipasa sn-1',3' estereoespecífica, obtenida de Mucor miehei, en forma libre e inmovilizada (Lipozyme IM-20). La lipasa de Candida cylindracea hidroliza un 85%-90% de los triacilgliceroles del aceite a las 47-50 horas de acción. La composición del hidrolizado es muy similar a la del aceite, y en los monoacilgliceroles remanentes la composición de ácidos grasos es poco definida, aunque predominan los de cadena corta (C6 y C8) y media (C10-C14). La enzima de Mucor miehei permite alcanzar sólo un 65% de hidrólisis, que se obtiene a las 30 horas en el caso de la enzima libre y a las 10 horas en el caso de la enzima inmovilizada (Lipozyme IM-20). La composición de ácidos grasos del hidrolizado es muy similar en ambos casos, destacando la presencia de ácidos grasos en el rango C8-C14, aunque con una composición muy diferente a la del aceite original. La composición de ácidos grasos del monoacilglicerol remanente muestra una marcada predominancia de ácido láurico (C12:0) en el producto de ambas formas de la enzima, lo cual indicaría que este ácido graso ocupa mayoritariamente la posición sn-2' de los triacilgliceroles del aceite de coco. Se discute la utilidad de las lipasas para obtener fracciones enriquecidas en ciertos ácidos grasos. También se discute la posible utilidad de la enzima de Mucor miehei para obtener fracciones enriquecidas en ácido láurico, el que por saponificación posterior puede ser obtenido en forma libre

    Métodos de seleção de microrganismos antagônicos a fitopatógenos: manual técnico.

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    Resumo: Este Manual tem como objetivo fornecer informações básicas sobre métodos já estabelecidos para seleção de microrganismos antagônicos a fitopatógenos no sentido de minimizar os esforços para obtenção segura de agentes com potencial de controle biológico. Procurou-se selecionar práticas rápidas e simples relacionadas com o assunto, mormente àquelas de interesse aos estudantes de cursos de pós-graduação ou de cursos isolados

    The Caveolin-1 Connection to Cell Death and Survival

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    Nunez, S (Nunez, S.)[ 1,4 ] 1. Fac Med, CEMC, Lab Comunicac Celulares, Santiago, Chile. 4. Univ Talca, Fac Hlth Sci, Talca, ChileCaveolins are a family of membrane proteins required for the formation of small plasma membrane invaginations called caveolae that are implicated in cellular trafficking processes. In addition to this structural role, these scaffolding proteins modulate numerous intracellular signaling pathways; often via direct interaction with specific binding partners. Caveolin-1 is particularly well-studied in this respect and has been attributed a large variety of functions. Thus, Caveolin-1 also represents the best-characterized isoform of this family with respect to its participation in cancer. Rather strikingly, available evidence indicates that Caveolin-1 belongs to a select group of proteins that function, depending on the cellular settings, both as tumor suppressor and promoter of cellular traits commonly associated with enhanced malignant behavior, such as metastasis and multi-drug resistance. The mechanisms underlying such ambiguity in Caveolin-1 function constitute an area of great interest. Here, we will focus on discussing how Caveolin-1 modulates cell death and survival pathways and how this may contribute to a better understanding of the ambiguous role this protein plays in cancer

    Obtención de fracciones altamente purificadas de ácido eicosapentaenoico y docosahexaenoico de aceite de sardina mediante cromatografía en columna utilizando resina impregnada con ion plata: Un procedimiento semipreparativo.

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    Pure fractions of eicosapentaenoic acid (ERA) and docosahexaenoic acid (DHA) were obtained from silver-resin column chromatography of ERA+DHA concentrates obtained from sardine oil. Two types of silver-impregnated resins were assayed; Amberlite IR-118H and Dowex 50 W-HCR-W2.The Amberlite-silver column allows the separation of almost pure fractions (98.5%) of ERA, being unable to separate DHA from other polyunsaturated fatty acids. The Dowex-silver column does not separate the ERA from the concentrate but allows the isolation of a highly purified fraction of DHA. The chromatographic procedure described may provide pure forms of two important n-3 polyunsaturated fatty acids for nutritional or pharmacological research or as substrates for the obtention of structured lipids.Mediante cromatografía en columna utilizando resinas impregnadas con ion plata se separaron fracciones puras de ácido eicosapentaenoico (EPA) y ácido docosahexaenoico (DHA) a partir de un concentrado de EPA+DHA obtenido de aceite de sardina. Se utilizaron dos tipos de resinas impregnadas con plata: Amberlite-IR 118H y Dowex 50 W-HCR-W2. La columna de Amberlite-plata permite la separación de fracciones casi puras de ERA (98,5%), siendo incapaz de separar el DHA de otros ácidos grasos poliinsaturados. La columna de Dowex-plata no separa el ERA a partir del concentrado, pero permite la obtención de una fracción de DHA de alta pureza. El procedimiento cromatográfico que se describe permite obtener fracciones puras de dos importantes ácidos grasos poliinsaturados de la serie n-3 que pueden ser utilizados para la investigación nutricional o farmacológica, o como sustratos para la obtención de lípidos estructurados
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