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Registros recuperados: 13 | |
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Puiatti,Guilherme Alves; Cecon,Paulo Roberto; Nascimento,Moysés; Nascimento,Ana Carolina Campana; Carneiro,Antônio Policarpo Souza; Silva,Fabyano Fonseca e; Puiatti,Mário; Cruz,Cosme Damião. |
ABSTRACT: The objective of this study was to adjust nonlinear quantile regression models for the study of dry matter accumulation in garlic plants over time, and to compare them to models fitted by the ordinary least squares method. The total dry matter of nine garlic accessions belonging to the Vegetable Germplasm Bank of Universidade Federal de Viçosa (BGH/UFV) was measured in four stages (60, 90, 120 and 150 days after planting), and those values were used for the nonlinear regression models fitting. For each accession, there was an adjustment of one model of quantile regression (τ=0.5) and one based on the least squares method. The nonlinear regression model fitted was the Logistic. The Akaike Information Criterion was used to evaluate the goodness of... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Quantile regression; Nonlinear regression; Allium sativum L.; Growth rate; Cluster analysis.. |
Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782020000100203 |
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Puiatti,Guilherme Alves; Cecon,Paulo Roberto; Nascimento,Moysés; Nascimento,Ana Carolina Campana; Carneiro,Antônio Policarpo Souza; Silva,Fabyano Fonseca e; Puiatti,Mário; Oliveira,Ana Carolina Ribeiro de. |
ABSTRACT: Plant growth analyses are important because they generate information on the demand and necessary care for each development stage of a plant. Nonlinear regression models are appropriate for the description of curves of growth, since they include parameters with practical biological interpretation. However, these models present information in terms of the conditional mean, and they are subject to problems in the adjustment caused by possible outliers or asymmetry in the distribution of the data. Quantile regression can solve these problems, and it allows the estimation of different quantiles, generating more complete and robust results. The objective of this research was to adjust a nonlinear quantile regression model for the study of dry matter... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Quantile regression; Nonlinear regression; Dry matter; Allium sativum L. |
Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782018000100203 |
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Sousa,Iábita Fabiana; Kunzle Neto,Johan Eugen; Muniz,Joel Augusto; Guimarães,Renato Mendes; Savian,Taciana Villela; Muniz,Fabiana Rezende. |
Cumulative germination of coffee has a longitudinal behavior mathematically characterized by a sigmoidal model. In the seed germination evaluation, the study of the germination curve may contribute to better understanding of this process. The aim of this study was to evaluate the goodness of fit of Logistic and Gompertz models, with independent and first-order autoregressive errors structure, AR (1), in the description of coffee (Coffea arabica L.) line Catuai vermelho IAC 99 germination, at five different potential germination. The data used were from an experiment conducted in 2011 at the Seed Analysis Laboratory of the Federal University of Lavras. The Logistic and Gompertz nonlinear models were appropriately adjusted to the percentage germination data.... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Growth models; Autocorrelated errors; Nonlinear regression; Germination potential; Regression and correlation. |
Ano: 2014 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782014001102016 |
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Silva,Fabyano Fonseca e; Resende,Marcos Deon V. de; Rocha,Gilson Silvério; Duarte,Darlene Ana S.; Lopes,Paulo Sávio; Brustolini,Otávio J.B.; Thus,Sander; Viana,José Marcelo S.; Guimarães,Simone E.F.. |
In the current post-genomic era, the genetic basis of pig growth can be understood by assessing SNP marker effects and genomic breeding values (GEBV) based on estimates of these growth curve parameters as phenotypes. Although various statistical methods, such as random regression (RR-BLUP) and Bayesian LASSO (BL), have been applied to genomic selection (GS), none of these has yet been used in a growth curve approach. In this work, we compared the accuracies of RR-BLUP and BL using empirical weight-age data from an outbred F2 (Brazilian Piau X commercial) population. The phenotypes were determined by parameter estimates using a nonlinear logistic regression model and the halothane gene was considered as a marker for evaluating the assumptions of the GS... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Bayesian LASSO; Nonlinear regression; SNP effects. |
Ano: 2013 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572013000400010 |
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Graybeal, Dale K.. |
A logistic growth equation with time and location varying parameters was used to model corn response to applied nitrogen. A nonlinear dummy-variable regression model provided a parsimonious representation of site and time effects on parameter values. The model was used to test for the equality of the mean marginal product of nitrogen fertilizer between locations on the coastal plain of North Carolina. Monte Carlo simulation and bootstrap simulation were used to construct finite sample covariance estimates. Results support rejection of the hypothesis that mean marginal products are equal when nitrogen is applied at 168 kg/ac. A comparison of bootstrapped errors and asymptotic errors suggests that results based on asymptotic theory are fairly reliable in... |
Tipo: Journal Article |
Palavras-chave: Bootstrap; Corn yield; Marginal product; Nitrogen fertilizer; Nonlinear regression; Crop Production/Industries; C200; C150; Q100. |
Ano: 2000 |
URL: http://purl.umn.edu/15502 |
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Furtado,Thais Destefani Ribeiro; Muniz,Joel Augusto; Silva,Edilson Marcelino; Fernandes,Jaqueline Gonçalves. |
Abstract Jabuticaba tree is native to the Atlantic Forest in Southern Brazil, and its fruit is widely consumed in the fresh form, but it is highly perishable, requiring conservation techniques. The aim of this study was to describe the drying kinetics of jabuticaba pulp at temperatures of 50 and 60°C, comparing the Henderson, Simple Three-Parameter Exponential, Lewis, Thompson, Fick and Wang and Sing regression models and estimating the Absolute Drying Rate (ADR) for the best model. Parameters were estimated using the SAS software. The evaluation of the quality in the adjustment and selection of models was made based on the adjusted determination coefficient, Residual Standard Deviation and Akaike Information Criterion. Models presented good adjustment to... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Food preservation; Moisture ratio; Nonlinear regression; Statistical models. |
Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-29452019000100903 |
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Leão,Tairone Paiva. |
ABSTRACT: The least limiting water range is a soil physical quality indicator, which is useful to predict the optimum water range for plant growth in a given soil and to study the effects of soil use and management over this optimum water range by integrating the effects of available water, penetration resistance and air filled porosity. This study tested six equations to fit water retention and penetration resistance surface responses used to determine the least limiting water range and present a simple algorithm written in the open source software R for fitting, calculation and visualization of the least limiting water range. Five soils from Brazil and Canada, under different use and management conditions were used to test the functions. The results show... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Nonlinear regression; Soil physical quality. |
Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162019001200172 |
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Mischan,Martha Maria; Pinho,Sheila Zambello de; Carvalho,Lídia Raquel de. |
Growth functions with upper horizontal asymptote do not have a maximum point, but we frequently question from which point growth can be considered practically constant, that is, from which point the curve is sufficiently close to its asymptote, so that the difference can be considered non-significant. Several methods have been employed for this purpose, such as one that verifies the significance of the difference between the curve and its asymptote using a t-test, and that of Portz et al. (2000), who used segmented regression. In the present work, we used logistic growth function, which has horizontal asymptote and one inflection point, and applied a new method consisting in the mathematical determination of a point in the curve from which the growth... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Nonlinear regression; Logistic model; Critical point of growth. |
Ano: 2011 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162011000100016 |
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Registros recuperados: 13 | |
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