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Search Results: 1 - 10 of 85239 matches for " Valle Basanta Maria del "
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Estimativa do volume máximo de calda para aplica??o foliar de produtos químicos na cultura de milho
Basanta, Maria del Valle;Dourado-Neto, Durval;García y García, Axel;
Scientia Agricola , 2000, DOI: 10.1590/S0103-90162000000200014
Abstract: with the objective of estimating the volume of water retained by corn leaves per unit area (ha) for chemigation purposes, a simple model is proposed. a field experiment was carried out to obtain the water interception on the aerial corn plant parts under a center pivot irrigation system. three plant populations were used to obtain different designs, the measurements having been performed at three phenological stages: i) 4-5 leaves; ii) 8 leaves and iii) 14 leaves. the water mass retained by the corn leaves was obtained considering the total plant mass (measured after irrigation), the plant dry weight and the plant constitution water mass. treatments were arranged in a split-plot design, with four replications. main plot treatment was plant population and subplot treatment was sampling date. total plant leaf area was evaluated for each sampling period. phenology and the relative crop development were evaluated periodically. results indicate that the proposed model can be used for this estimate.
Estimativa do volume máximo de calda para aplica o foliar de produtos químicos na cultura de milho
Basanta Maria del Valle,Dourado-Neto Durval,García y García Axel
Scientia Agricola , 2000,
Abstract: Com o objetivo de estimar o volume de água por hectare retido na folhagem da cultura de milho para fins de quimiga o (alvo folha), é proposto um modelo, tendo sido conduzido um experimento em que foi avaliada a intercepta o de água pela parte aérea das plantas de milho sob diferentes laminas de irriga o aplicadas via piv central. Foi semeado um híbrido de milho, em três densidades, obtendo-se assim três arranjos espaciais diferentes. As avalia es foram realizadas em 3 estádios fenológicos: i) 4-5 folhas; ii) 8 folhas e iii) 14 folhas. A quantidade de água retida nas folhas das plantas foi estimada subtraindo à massa total da planta medida após a passagem do piv , a massa de matéria seca e a água constitutiva das plantas. Para a análise estatística dos resultados, utilizou-se um delineamento experimental em parcelas subdivididas no tempo, com quatro repeti es. O tratamento principal foi a popula o de plantas e o subtratamento a data de amostragem. A área foliar foi avaliada em cada amostragem. A fenologia e o desenvolvimento relativo da cultura foram avaliados periodicamente. Os resultados permitiram verificar que o modelo proposto é utilizável.
Temperatura do ar, rendimento de gr?os de milho e caracteriza??o fenológica associada à soma calórica
Gadioli, Jo?o Luiz;Dourado-Neto, Durval;García y García, Axel;Valle Basanta, Maria del;
Scientia Agricola , 2000, DOI: 10.1590/S0103-90162000000300001
Abstract: with the purpose of evaluating the effect of the mean daily air temperature on grain yield and to predict the occurrence of the maize crop phenological phases as function of heat units, a field experiment was carried out using three hybrids with different heat unit requirements and three sowing dates. to estimate grain productivity, different yield components were determinated. crop phenology was associated to the relative degree-days, for which a linear relation was observed. there is a mean air temperature corresponding to maximum grain yield, and the crop phenological phases can be predicted knowing the local historical temperature series and the thermic index for physiological maturity.
Temperatura do ar, rendimento de gr os de milho e caracteriza o fenológica associada à soma calórica
Gadioli Jo?o Luiz,Dourado-Neto Durval,García y García Axel,Valle Basanta Maria del
Scientia Agricola , 2000,
Abstract: Com os objetivos de avaliar o efeito da temperatura média do ar no rendimento de gr os e de prever a época de ocorrência dos estádios fenológicos da cultura de milho em fun o da soma calórica, foi conduzido um experimento de campo utilizando três híbridos, com diferentes exigências térmicas, em três diferentes épocas de semeadura. Para estimativa do rendimento de gr os foram determinados seus diferentes componentes, onde se observou um decréscimo do rendimento com aumento da temperatura em fun o das épocas de semeadura utilizadas. A fenologia foi associada ao número relativo de graus-dia, onde se observou uma rela o linear. Há uma temperatura média do ar correspondente ao máximo rendimento de gr os, e os estádios fenológicos da cultura podem ser previstos através do conhecimento prévio da série histórica de temperatura da localidade e da soma calórica requerida para o ponto de maturidade fisiológica.
Logistic rice model for dry matter and nutrient uptake
García y García Axel,Dourado-Neto Durval,Basanta Maria del Valle,López Ovejero Ramiro Fernando
Scientia Agricola , 2003,
Abstract: The temporal variation of cumulative dry matter can be represented by a sigmoidal curve and the temporal variation of nutrient uptake follows this characteristic shape. Therefore, modeling the temporal variation of cumulative dry matter allows estimating nutrient uptake along the crop cycle. The objective of this study was to propose a sine model to estimate dry matter and macronutrient uptake, and to estimate the moments of maximum N and K uptake rates for the rice crop. The field experiment was carried out on a wetland area of Piracicaba, SP, Brazil, consisting of an Humic Haplaquept. The chosen rice variety was IAC 103, a middle season cycle and high yield. Observed variables were dry matter of different plant parts (root, leaf and stem, and panicle) and macronutrient contents per unit dry matter. A sine model was proposed for the cumulative variation of these variables, based on biological events that occurred during the crop cycle. The temporal variation of nutrient uptake was estimated and a lower accuracy was observed for K uptake. The maximum absorption rate for N and K was found at 56% of the relative development of the crop, corresponding to 60 days after emergence in this experiment. The proposed model presented a satisfactory behavior to define the order of magnitude of estimated dry matter and macronutrient uptake by the rice crop and maximum N and K uptake rates.
Logistic rice model for dry matter and nutrient uptake
García y García, Axel;Dourado-Neto, Durval;Basanta, Maria del Valle;López Ovejero, Ramiro Fernando;Favarin, José Laércio;
Scientia Agricola , 2003, DOI: 10.1590/S0103-90162003000300011
Abstract: the temporal variation of cumulative dry matter can be represented by a sigmoidal curve and the temporal variation of nutrient uptake follows this characteristic shape. therefore, modeling the temporal variation of cumulative dry matter allows estimating nutrient uptake along the crop cycle. the objective of this study was to propose a sine model to estimate dry matter and macronutrient uptake, and to estimate the moments of maximum n and k uptake rates for the rice crop. the field experiment was carried out on a wetland area of piracicaba, sp, brazil, consisting of an humic haplaquept. the chosen rice variety was iac 103, a middle season cycle and high yield. observed variables were dry matter of different plant parts (root, leaf and stem, and panicle) and macronutrient contents per unit dry matter. a sine model was proposed for the cumulative variation of these variables, based on biological events that occurred during the crop cycle. the temporal variation of nutrient uptake was estimated and a lower accuracy was observed for k uptake. the maximum absorption rate for n and k was found at 56% of the relative development of the crop, corresponding to 60 days after emergence in this experiment. the proposed model presented a satisfactory behavior to define the order of magnitude of estimated dry matter and macronutrient uptake by the rice crop and maximum n and k uptake rates.
Runaway massive stars as variable gamma-ray sources
Maria V. del Valle,Gustavo E. Romero
Physics , 2014, DOI: 10.1051/0004-6361/201322308
Abstract: Runaway stars are ejected from their formation sites well within molecular cores in giant dark clouds. Eventually, these stars can travel through the molecular clouds, which are highly inhomogeneous. The powerful winds of massive runaway stars interact with the medium forming bowshocks. Recent observations and theoretical modelling suggest that these bowshocks emit non-thermal radiation. As the massive stars move through the inhomogeneous ambient gas the physical properties of the bowshocks are modified, producing changes in the non-thermal emission. We aim to compute the non-thermal radiation produced in the bowshocks of runaway massive stars when travelling through a molecular cloud. We calculate the non-thermal emission and absorption for two types of massive runaway stars, an O9I and an O4I, as they move through a density gradient. We present the spectral energy distributions for the runaway stars modelled. Additionally, we obtain light curves at different energy ranges. We find significant variations in the emission over timescales of $\sim$ 1 yr. We conclude that bowshocks of massive runaway stars, under some assumptions, might be variable gamma-ray sources, with variability timescales that depend on the medium density profile. These objects might constitute a population of galactic gamma-ray sources turning on and off within years.
Effect of Risperidone and Fluoxetine on the Movement and Neurochemical Changes of Zebrafish  [PDF]
Maria Jimena Prieto, Hector Carreno Gutierrez, Rosario Arévalo Arévalo, Nadia S. Chiaramoni, Silvia del Valle Alonso
Open Journal of Medicinal Chemistry (OJMC) , 2012, DOI: 10.4236/ojmc.2012.24016
Abstract: Brain developmental disorders in humans, including Autism Spectrum Disorders (ASD) and Downs syndrome, have been linked to increased serotonin levels. This work was designed to study changes in serotonin levels in the early stages of development with two classes of antipsychotic drugs: Risperidone, a drug that blocks serotonin and dopamine receptors, and fluoxetine, a serotonin reuptake inhibitor. The use of antipsychotic drugs is a solid choice to study the decrease and increase of these neurotransmitters and their influence on development. The study of these parameters will give an idea of the effects of serotonin in early developmental stages. To this end, we examined the effects of risperidone and fluoxetine on the locomotor activity, heart rate and brain development of zebrafish larvae. Our results showed that in larvae exposed to fluoxetine alone, swimming was significantly increased at 9 dpf (days post-fertilization). Erratic and abnormal movements were observed suggesting a toxic effect of fluoxetine. No erratic swimming was observed in larvae treated with fluoxetine plus risperidone. Both drugs presented morphological changes in dopaminergic neurons and mononeurons. Exposure to fluoxetine plus risperidone indicated possible reversal effects. Studies in zebrafish allow obtaining new insights into the side effects of these drugs as well as into the brain control of locomotor activity. Testing several drug-induced changes in behavior and serotonin levels is one of the experimental approaches for screening a new therapeutically relevant compound, and thus, merits further research.
Effect of CuI Anode Buffer Layer on the Growth of Polymers Thin Films and on the Performances of Organic Solar Cells  [PDF]
Pedro Pablo Zamora, Fernando Raul Díaz, Maria Angelica del Valle, Linda Cattin, Guy Louarn, Jean Christina Bernède
Natural Resources (NR) , 2013, DOI: 10.4236/nr.2013.41A016
Abstract:

Organic photovoltaic cells using polymer belonging to the aniline-heteroaryl family as electron donor have been achieved by thermal evaporation. We show that the properties of the polymer film, morphology, molecule order and conductivity depend strongly on the bottom anode buffer layer. While cells without anode buffer layer or with MoO3 or CuI anode buffer layer have been probed, we show that CuI allows improving strongly the cells efficiency through an improvement of the morphology and conductivity of the polymer film. This shows that although it is necessary a good band matching at the interface, this is not sufficient, because the templating effect of CuI on the polymer film is primordial for photovoltaic cells improvement.

A situa??o de trabalho do pessoal de enfermagem no contexto de um hospital argentino: um estudo sob a ótica da ergonomia
Del Valle Royas, Azucena;Marziale, Maria Helena Palucci;
Revista Latino-Americana de Enfermagem , 2001, DOI: 10.1590/S0104-11692001000100015
Abstract: the present study aimed at characterizing the work situation of the nursing personnel from an argentine hospital through the identification of the characteristics of the workers, the executed activities and the work environment, using the methodological fundamentals of ergonomics. in order to diagnose the work situation, the author performed 74 interviews with the workers, 17 nurses and 57 nursing auxiliaries. findings showed that the work situation in the studied presents problems related to the work organization, tasks division, lack of a policy directed to improve professional capacities and safety at work, promotion of worker's health and adequacy of the materials, equipments. the authors presented suggestions based on ergonomics in order to minimize or to eliminate the detected problems.
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