Modelos de crescimento animal para tempos irregulares

Cassiano, Fernando Ribeiro; Sáfadi, Thelma

doi:10.1590/s0100-204x2015001100015

Cited by 6 publications

(6 citation statements)

References 11 publications

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“…Similar findings were reported by MUNIZ et al (2017), MUIANGA et al (2016) and CASSIANO & SÁFADI (2015) in their studies on growth, in which the residual dependence was modeled by autoregressive order AR P . In the current study, the logistic model offered the best results corroborating the findings of PRADO et al, (2013), who also reported a better fit by this model in their studies on the green dwarf cocus fruit diameter.…”

Section: Resultssupporting

confidence: 82%

“…When the residuals are independent, the parameters Ø i are null, and consequently u i -ɛ i (MUIANGA et al, 2016). CASSIANO & SÁFADI (2015) reiterated that time-ordered sets of data are normally autocorrelated, which must be taken into account and modeled to ensure more highly accurate estimates and better quality in the adjustment of the models.…”

Section: Methodsmentioning

confidence: 99%

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The use of the nonlinear models in the growth of pears of ‘Shinseiki’ cultivar

et al. 2017

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The goal of this study was to elucidate the growth and development of the Asian pear fruit, on the grounds of length, diameter and fresh weight determined over time, using the non-linear Gompertz and Logistic models. The specifications of the models were assessed utilizing the R statistical software, via the least squares method and iterative Gauss-Newton process (DRAPER & SMITH, 2014). The residual standard deviation, adjusted coefficient of determination and the Akaike information criterion were used to compare the models. The residual correlations, observed in the data for length and diameter, were modeled using the second-order regression process to render the residuals independent. The logistic model was highly suitable in demonstrating the data, revealing the Asian pear fruit growth to be sigmoid in shape, showing remarkable development for three variables. It showed an average of up to 125 days for length and diameter and 140 days for fresh fruit weight, with values of 72mm length, 80mm diameter and 224g heavy fat.

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Section: Resultssupporting

confidence: 82%

Section: Methodsmentioning

confidence: 99%

The use of the nonlinear models in the growth of pears of ‘Shinseiki’ cultivar

et al. 2017

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“…This fact evidenced that for the description of growth characteristics of the group of animals under study, the parameterization and the value of m = 3/4 of great importance to obtain better fits. In practice, it is common to neglect the models with a practical or biological interpretation for parameter b, as in the studies of , Silveira et al (2011), Cassiano & Sáfadi (2015), Jacob et al (2015), and Rodrigues et al (2018). Nevertheless, if the parameterization of Model 3 is used, considering the correct allometry, a better fit can be achieved in these studies.…”

Section: Resultsmentioning

confidence: 99%

“…The study of growth curves of these animals by nonlinear models is very attractive, as they are flexible and summarize the characteristics of the species development in a few parameters with biological interpretation. In practice, this knowledge allows of the adoption of strategies to enhance or mitigate certain characteristics of the animals under study (Freitas, 2005;Cassiano & Sáfadi, 2015;Souza et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Growth curves of meat-producing mammals by von Bertalanffy’s model

Fernandes

Pereira

et al. 2019

Pesq. agropec. bras.

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The objective of this work was to evaluate how the parameterization and the application of different allometric values affect the obtention of the most adequate fit of von Bertalanffy’s model, in the description of the growth curve of meat-producing mammals (bovine, pigs, rabbits, and sheep). Among the nonlinear models, von Bertalanffy’s has been very often applied in several areas, with different parameterizations. This model has been commonly used with an allometric value of m = 2/3; however, for mammals, it is believed that this value can be m = 3/4. The analyzed data referring to the mass of meat-producing mammals according to their age were obtained from research institutions and from the literature. The results showed that von Bertalanffy’s model, with the allometric value of m = 3/4 and the used parameterization, provided better adjustments to quality evaluators. Besides, the model softened the overestimation of parameter a, giving a direct interpretation of parameter b, with the lowest values for curvature measurements, mainly for the parametric ones, and provided more reliable adjustments. Von Bertalanffy’s model can be used in the description of the growth curves of meat-producing mammals.

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“…Several iterative methods are used, especially Gauss-Newton (PEREIRA et al, 2005;MENDES et al, 2008;ZEVIANI et al, 2012;CARNEIRO et al, 2014;FERNANDES at al., 2015). In regression studies, it is usual to admit in the estimation process and inference under parameters that the errors are independent, which does not necessarily occur when working with time-ordered data that are potentially correlated (CASSIANO; SÁFADI, 2015). In this case, the model parameters estimates can be biased, with values below or above the actual value (GUEDES et al, 2014;MAZZINI et al, 2005;FERNANDES et al, 2014), and one should consider the autocorrelation structure present in data in the model adjustment (PRADO et al, 2013a;RIBEIRO et al, 2018), as it may affect the value of the standard error estimate.…”

Section: Introductionmentioning

confidence: 99%

Description of the growth of pequi fruits by nonlinear models

et al. 2018

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Descrição do crescimento de frutos de pequizeiro por modelos não linearesResumo -O pequizeiro é uma espécie nativa do cerrado brasileiro, com ampla distribuição geográfica, cujo fruto é bastante apreciado na culinária, compondo pratos tradicionais. Em geral, o fruto do pequi é consumido quando maduro, na forma in natura ou nos diversos, produtos derivados tais como óleos, licores, doces, sorvetes, entre outros, envolvendo importante atividade socioeconômica geradora de emprego e renda na agricultura familiar. Este trabalho teve por objetivo avaliar o ajuste dos modelos Brody, Gompertz, Logístico e Von Bertalanffy no crescimento e no desenvolvimento de frutos de pequi, com base em suas características físicas, como diâmetro longitudinal e transversal, e massa fresca obtidos ao longo do tempo. Os parâmetros foram estimados por meio de rotinas do software R, utilizando-se do método de mínimos quad rados e o processo iterativo de Gauss-Newton. O ajuste dos modelos foi comparado, utilizando os critérios: desvio-padrão residual, coeficiente de determinação ajustado e critério de informação de Akaike corrigido. Em geral, os dados não apresentaram estrutura de erros correlacionados, e o modelo Von Bertalanffy não se ajustou aos dados de massa fresca. Os modelos apresentaram boa qualidade no ajuste aos dados de crescimento de pequi, exceto o modelo Brody para a variável massa fresca. Os modelos Gompertz e Logístico foram os que melhor descreveram as variáveis, sendo o Gompertz o mais indicado para descrever os dados de diâmetro e de massa. Com base no ajuste, observou-se um crescimento inicial lento até cerca de 20 dias após a antese; após este período, o fruto desenvolveu-se de modo mais acelerado até 90 dias e, então, apresentou tendência à estabilidade até o final da avaliação, aos 117 dias após a antese, com caráter sigmoide da curva. O fruto de pequizeiro obteve valores finais, em média, de 7,1 cm de diâmetro transversal, 6,8 cm de diâmetro longitudinal e 113g de massa fresca. Termos de indexação: Modelos de crescimento, medidas biométricas, curvas sigmoides, ajuste de modelos, pequi.Abstract-Pequi tree is a species native to the Brazilian cerrado, with wide geographic distribution, whose fruit is very appreciated in cooking, composing traditional dishes. In general, pequi fruit is consumed when ripe in the fresh form or in the various derived products such as oils, liqueurs, sweets, ice creams among others, involving important socioeconomic activity generating employment and income in family agriculture. The aim of this study was to evaluate the adjustment of Brody, Gompertz, Logistic and Von Bertalanffy models in the growth and development of pequi fruits based on their physical characteristics such as longitudinal and cross-sectional diameter and fresh mass obtained over time. Parameters were estimated using R software routines, using the least squares method and the Gauss-Newton iterative process. The adjustment of models was compared using the following criteria: residual standard deviation, adjusted determinati...

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Modelos de crescimento animal para tempos irregulares

Cited by 6 publications

References 11 publications

The use of the nonlinear models in the growth of pears of ‘Shinseiki’ cultivar

The use of the nonlinear models in the growth of pears of ‘Shinseiki’ cultivar

Growth curves of meat-producing mammals by von Bertalanffy’s model

Description of the growth of pequi fruits by nonlinear models

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