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| Registros recuperados: 233 | |
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| Pereira,Gener Tadeu; Souza,Zigomar Menezes de; Teixeira,Daniel De Bortoli; Montanari,Rafael; Marques Júnior,José. |
| The sampling scheme is essential in the investigation of the spatial variability of soil properties in Soil Science studies. The high costs of sampling schemes optimized with additional sampling points for each physical and chemical soil property, prevent their use in precision agriculture. The purpose of this study was to obtain an optimal sampling scheme for physical and chemical property sets and investigate its effect on the quality of soil sampling. Soil was sampled on a 42-ha area, with 206 geo-referenced points arranged in a regular grid spaced 50 m from each other, in a depth range of 0.00-0.20 m. In order to obtain an optimal sampling scheme for every physical and chemical property, a sample grid, a medium-scale variogram and the extended Spatial... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Simulation; Geostatistics; Sugar cane. |
| Ano: 2013 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832013000500002 |
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| Dallacort,Rivanildo; Freitas,Paulo S. L. de; Faria,Rogério T. de; Gonçalves,Antonio C. A.; Jácome,Aleksandra G.; Rezende,Roberto. |
| The performance of the CROPGRO-Drybeans model for the prediction of soil water balance, as well as growth components and bean crop yield, was assessed using data from two field experiments conducted at the State University of Maringá Irrigation Technical Center, Paraná - Brazil, (latitude 23º27'S, longitude 51º57' and altitude 542 m), during the 2005 and 2006 growing season. The model simulations correlated well with measured soil moisture (r > 0.7) for both experiments. However, there were high discrepancies between measured and simulated soil moisture values on the days after rainfall. In addition, it was found that the model exaggerates the effect of water stress during the flowering phase, which leds to underprediction (19 and 29%) of crop yield. |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Water stress; Soil moisture; Simulation. |
| Ano: 2010 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662010000400002 |
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| Mamann,Ângela T. W De; Silva,José A. G. da; Scremin,Osmar B.; Mantai,Rubia D.; Scremin,Ari H.; Dornelles,Eldair F.. |
| ABSTRACT Nitrogen use efficiency in wheat biomass and grain yields can be favored by the biopolymer hydrogel. The objective of the study was to analyze the use of the biopolymer hydrogel applied to the seed in the optimization of fertilizer-N on wheat biomass and grain yields, under different conditions of agricultural year and succession systems of high and reduced release of residual-N. In the study, two experiments were conducted, with different farming systems, soybean/wheat and maize/wheat, one to quantify the biomass yield rate and the other to determine grain yield. The experiments were conducted in the years 2014 and 2015, in a randomized block design with four replicates in a 4 x 4 factorial scheme, corresponding to hydrogel doses (0, 30, 60 and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Triticum aestivum; Simulation; Farming systems; Water stress. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662017001000697 |
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| Prado,Giuliani do. |
| ABSTRACT The study aimed to evaluate the water distribution from a medium-size sprinkler working in solid set sprinkler systems. Water distribution radial curves from the sprinkler operating under four nozzle diameter combinations (4.0 x 4.6; 5.0 x 4.6; 6.2 x 4.6 and; 7.1 x 4.6 mm) and four working pressures (196; 245; 294 and 343 kPa) were evaluated on the sprinkler test bench of the State University of Maringá, in Cidade Gaúcha, Paraná, Brazil. The sixteen water distribution curves were normalized and subjected to clustering analysis (K-Means algorithm), identifying the occurrence of normalized distribution curves with three different geometric shapes. A computer algorithm, in Visual Basic for Applications in Excel spreadsheet, was developed to simulate... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Distribution curve; Simulation; Distribution uniformity. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662016000300195 |
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| Rekaya,Romdhane; Robbins,Kelly. |
| In recent years there has been much focus on the use of single nucleotide polymorphism (SNP) fine genome mapping to identify causative mutations for traits of interest; however, many studies focus only on the marginal effects of markers, ignoring potential gene interactions. Simulation studies have show that this approach may not be powerful enough to detect important loci when gene interactions are present. While several studies have examined potential gene interaction, they tend to focus on a small number of SNP markers. Given the prohibitive computation cost of modeling interactions in studies involving a large number SNP, methods need to be develop that can account for potential gene interactions in a computationally efficient manner. This study adopts... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Genome; Simulation; SNP. |
| Ano: 2009 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982009001300011 |
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| Vargas-Villamil,Luis Manuel; Ku-Vera,Juan Carlos; Vargas-Villamil,Felipe; Medina-Peralta,Salvador; Avila-Vales,Eric José; Aranda-Ibañez,Emilio Manuel; Avendaño-Reyes,Leonel. |
| The objective of this study was to use the Turix model (a new mechanistic dynamic model that can be used for feed evaluation under tropical conditions), along with in situ and in vitro sugar cane experimental data from a previous study, to evaluate sugar cane kinetics through estimation of three parameters associated with ruminal bacterial growth: kM,SmL, the substrate uptake; kLM, the bacterial growth from intermediate metabolite; and Y VFAP,FS, the products related to volatile fatty acid yield. Values of these parameters for the whole sugar cane and its neutral detergent fiber (NDF) and acid detergent fiber (ADF) fractions were: a) kM, SmL, 16.20, 50.47 and 21.97 mL h-1 (mg M)-1 ; b) kLM, 96.00, 543.00 and 1,680.00 h-1 ; and, 1.02, 0.40 and 0.23 g g-1 ,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Model fitting; Parameter estimation; Ruminant; Simulation; Sugar cane. |
| Ano: 2013 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982013000400009 |
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| Cunha,Daniel de Noronha Figueiredo Vieira da; Pereira,José Carlos; Campos,Oriel Fajardo de; Gomes,Sebastião Teixeira; Braga,José Luis; Martuscello,Janaina Azevedo. |
| The objective of the study was to compare through simulation Holstein and Jersey breed herds, considering the farm size, zootechnical and economic indexes and profitability of the activity, by using different systems of bonus payment for milk price based in percentage of fat and protein in the milk. The comparisons were made, initially, disregarding the bonus payment for milk price based on the increase in the fat and protein percentage in milk. After that, the profitability of the activity was compared considering bonus payment for milk price of the Jersey breed herd, for each unit increment in fat and protein percentage in milk above those obtained with the Holstein breed herd. Finally, the profitability of the activity was compared by using the bonus... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Dairy cattle; Milk fat; Milk protein modeling; Simulation. |
| Ano: 2010 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982010000400028 |
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| Meneghetti,Carlos Renato; Tizzei,Alexandre; Cappelli,Nelson Luis; Umezu,Claudio Kiyoshi; Bezzon,Guilherme. |
| Studies of control strategies for refrigeration systems observe, among other variables, the dynamic behavior of temperature and the consumption of electrical energy. Aiming to contribute to these studies, this work presents the proposal and validation of a mathematical model for the cooling system of a cold-storage unit. The model approximates the dynamics and interdependence of the variables, to first-order systems with time delay and the summation of effects. The input variables available are the frequency of compressor activation and the thermal load imposed on the unit, and as output variables, the air temperature both at the evaporator inlet and at the centre of the chamber, as well as the electrical power consumed by the compressor. The results... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Variable rotation; Simulation; Agricultural products-storage; Electrical energy-consumption. |
| Ano: 2013 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1806-66902013000200010 |
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| Meireles,Elza Jacqueline Leite; Pereira,Antonio Roberto; Sentelhas,Paulo Cesar; Stone,Luis Fernando; Zimmermann,Francisco José Pfeilsticker. |
| Simulation models are important tools for the analysis of cultivated systems to estimate the performance of crops in different environments. The CROPGRO- model (DSSAT) was calibrated and validated using Carioca bean (Phaseolus vulgaris L.) to estimate yield and the development of the crop, sown in three row spacings (0.4, 0.5, and 0.6 m) and two fertilization rates (300 and 500 kg ha-1 of 4-30-16 N-P-K), in Santo Antônio de Goiás, GO, Brazil. To calibrate the model a combination of the genetic coefficients that characterize the phenology and morphology of the dry bean crop was used to obtain the best possible fit between predicted and observed anthesis and physiological maturity dates, leaf area index (LAI), total dry matter (TDM), yield components, and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: DSSAT; Dry bean; Simulation. |
| Ano: 2002 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162002000400016 |
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| Conceição,Marco Antônio Fonseca; Coelho,Rubens Duarte. |
| Experimental determination of microsprinkler droplets is difficult and time-consuming. This determination, however, could be achieved using ballistic models. The present study aimed to compare simulated and measured values of microsprinkler droplet diameters. Experimental measurements were made using the flour method, and simulations using a ballistic model adopted by the SIRIAS computational software. Drop diameters quantified in the experiment varied between 0.30 mm and 1.30 mm, while the simulated between 0.28 mm and 1.06 mm. The greatest differences between simulated and measured values were registered at the highest radial distance from the emitter. The model presented a performance classified as excellent for simulating microsprinkler drop... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Irrigation; Modeling; Simulation. |
| Ano: 2003 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162003000400025 |
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| Silva,Gabi Nunes; Tomaz,Rafael Simões; Sant'Anna,Isabela de Castro; Nascimento,Moysés; Bhering,Leonardo Lopes; Cruz,Cosme Damião. |
| Analysis using Artificial Neural Networks has been described as an approach in the decision-making process that, although incipient, has been reported as presenting high potential for use in animal and plant breeding. In this study, we introduce the procedure of using the expanded data set for training the network. Wealso proposed using statistical parameters to estimate the breeding value of genotypes in simulated scenarios, in addition to the mean phenotypic value in a feed-forward back propagation multilayer perceptron network. After evaluating artificial neural network configurations, our results showed its superiority to estimates based on linear models, as well as its applicability in the genetic value prediction process. The results further... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Genetic value; Statistics; Simulation; Artificial intelligence; Training strategy. |
| Ano: 2014 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162014000600008 |
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| Registros recuperados: 233 | |
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