scholarly journals Double sigmoidal models describing the growth of coffee berries

2017 ◽  
Vol 47 (8) ◽  
Author(s):  
Tales Jesus Fernandes ◽  
Adriele Aparecida Pereira ◽  
Joel Augusto Muniz
Keyword(s):  
Nonlinear Model ◽  
Growth Curve ◽  
Growth Pattern ◽  
Logistic Model ◽  
Least Squares Method ◽  
Logistic Models ◽  
Fresh Mass ◽  
R Software ◽  
Over Time ◽  
Mass Accumulation

ABSTRACT: This study aimed to verify if the growth pattern of coffee berries, considering fresh mass accumulation over time, is double sigmoid and to select the most suitable nonlinear model to describe such behavior. Data used consisted of fourteen longitudinal observations of average fresh mass of coffee berries obtained in an experiment with the cultivar Obatã IAC 1669-20. The fits provided by the Logistic and Gompertz models were compared in their single and double versions. Parameters were estimated using the least squares method using the Gauss-Newton algorithm implemented in the nls function of the R software. It can be concluded that the growth pattern of the coffee fruit, in fresh mass accumulation, is double sigmoid. The double Gompertz and double Logistic models were adequate to describe such a growth curve, with a superiority of the double Logistic model.

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

2017 ◽  
Vol 48 (1) ◽  
Author(s):  
Thais Destefani Ribeiro ◽  
Taciana Villela Savian ◽  
Tales Jesus Fernandes ◽  
Joel Augusto Muniz
Keyword(s):  
Logistic Model ◽  
Least Squares Method ◽  
Nonlinear Models ◽  
Logistic Models ◽  
Information Criterion ◽  
Fruit Weight ◽  
Coefficient Of Determination ◽  
Pear Fruit ◽  
Asian Pear ◽  
Residual Correlations

ABSTRACT: 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.

scholarly journals Description of the growth of pequi fruits by nonlinear models

2018 ◽  
Vol 40 (4) ◽  
Author(s):  
Thais Destefani Ribeiro ◽  
Ricardo Wagner Pacopahyba de Mattos ◽  
Augusto Ramalho de Morais ◽  
Joel Augusto Muniz
Keyword(s):  
Least Squares Method ◽  
Nonlinear Models ◽  
Logistic Models ◽  
Fresh Mass ◽  
Initial Growth ◽  
Von Bertalanffy ◽  
Growth Data ◽  
Cross Sectional ◽  
Mass Data ◽  
Days After Anthesis

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 determination coefficient and corrected Akaike information criterion. In general, data presented no correlation error structure and the Von Bertalanffy model did not fit fresh mass data. The models presented good quality in the adjustment to pequi growth data, except for the Brody model for fresh mass. The Gompertz and Logistic models were those that best described variables, and the Gompertz model was the most suitable to describe diameter and mass data. Based on the adjustment, a slow initial growth was observed up to about 20 days after anthesis; after this period, the fruit developed more rapidly up to 90 days and then presented a tendency to stability until the end of the evaluation period at 117 days after anthesis, with sigmoid curve character. Pequi fruits obtained final average value of 7.1 cm for cross-sectional diameter, 6.8 cm for longitudinal diameter and 113g for fresh mass.

scholarly journals Highlighting Features of Spatiotemporal Spread of Powdery Mildew Epidemics in the Vineyard Using Statistical Modeling on Field Experimental Data

2009 ◽  
Vol 99 (4) ◽  
pp. 411-422 ◽  
Author(s):  
A. Calonnec ◽  
P. Cartolaro ◽  
J. Chadœuf
Keyword(s):  
Experimental Data ◽  
Disease Management ◽  
Powdery Mildew ◽  
Statistical Modeling ◽  
Logistic Model ◽  
Field Data ◽  
Logistic Models ◽  
Rate Of Progression ◽  
Over Time

A greater understanding of the development of powdery mildew epidemics on vines would improve disease management by making assessments of the risk of invasion more accurate. We characterized the spatiotemporal spread of epidemics in the vineyard, quantified their variability, and identified the factors responsible for it. We described changes in the probability of infection of a leaf in a plot over time and as a function of distance from a source of disease. Logistic models were fitted to field data from artificially inoculated plots. The velocity of spread decreased along the row and increased in the direction of the prevailing winds. The rate of progression over time was plot dependent, and the velocity was dependent on the vigor of the vine (0.1 to 0.27 m day–1 in areas of moderate vigor and 1.1 m day–1 in areas of high vigor). When applied to a larger plot with natural primary foci, the spatiotemporal logistic model showed that the velocity and the slope of the gradient in space depended on the foci; however, the velocity remained in the same range. During the period of highest susceptibility for grape, the probability of a leaf becoming infected increased from 2.5 to 13%. Our logistic model was able to predict changes in disease over time of its extension within the plot; however, the crop heterogeneity prevented prediction of variability of disease at the vine scale.

scholarly journals Development of Interest and Role of Choice During Sequential Knowledge Acquisition

2018 ◽  
Author(s):  
Greta M. Fastrich ◽  
Kou Murayama
Keyword(s):  
Knowledge Acquisition ◽  
Growth Curve ◽  
School Environment ◽  
Interest Development ◽  
Growth Curve Modelling ◽  
Over Time

Interest is an important motivational element for learning in the school environment. However, little research has directly addressed how interest develops over time as knowledge accumulates. To gain a better understanding of interest development, we developed a paradigm where participants gain step-by-step information about lesser known countries. After reading each piece of information, participants rated their interest in and liking of the country. Growth-curve modelling showed that interest grows during knowledge acquisition until it eventually stalls and starts to decline. We also found that the opportunity to choose information boosted the growth in interest and delayed its decline. Further analysis revealed that people disengaged from a topic (i.e. stopped accessing information about a particular country) when their interest started to decrease.

The Psychological Well-Being of Taiwanese Youth

2009 ◽  
Vol 24 (3) ◽  
pp. 397-429 ◽  
Author(s):  
Chin-Chun Yi ◽  
Chyi-In Wu ◽  
Ying-Hwa Chang ◽  
Ming-Yi Chang
Keyword(s):  
Depressive Symptoms ◽  
Growth Curve ◽  
Panel Study ◽  
School Context ◽  
Subsequent Development ◽  
Well Being ◽  
Quadratic Growth ◽  
School Factors ◽  
Psychological Well Being ◽  
Over Time

This study examines the growth trajectory of the psychological well-being of Taiwanese adolescents from early to late adolescence. Under the competitive educational system in Taiwan, family and school context are two major loci accounting for the developmental outcome. Data are taken from the Taiwan Youth Project, which is a longitudinal panel study of 2696 students since the year 2000. The study uses individual depressive symptoms as the dependent variable. Family cohesion, family educational strategy as well as classroom effects at school are chosen to indicate the potential contextual influence. Using the latent growth curve method, the analysis confirms that family and school factors do produce different effects over time. Family context is salient at the initial status, but not for subsequent development. Class cohesion as well as adolescents' perceptions of unfairness by teachers determine the depressive level, the linear slope and the non-linear quadratic growth curve. In other words, once the adolescent gets used to junior high school, the school context tends to exert more pronounced effects. Further analysis on gender comparisons indicates that selective family and school effects are more pronounced among females, with a greater degree of depressive symptoms over time. The article concludes that while family and school have different impacts on the growth curve of individual depressive symptoms, the school context exerts salient effects over an adolescent's life course.

scholarly journals Growth in weight and of some tissues in the bullfrog: fitting nonlinear models during the fattening phase

2014 ◽  
Vol 38 (6) ◽  
pp. 598-606 ◽  
Author(s):  
Marcelo Maia Pereira ◽  
Cleber Fernando Menegasso Mansano ◽  
Edney Pereira da Silva ◽  
Marta Verardino De Stéfani
Keyword(s):  
Food Intake ◽  
Logistic Model ◽  
Fat Body ◽  
Nonlinear Models ◽  
Logistic Models ◽  
Live Weight ◽  
Initial Weight ◽  
Expected Values ◽  
Growth Of Animals ◽  
Cumulative Food Intake

Knowledge of the growth of animals is important so that zootechnical activity can be more accurate and sustainable. The objective of this study was to describe the live weight, development of liver tissue and fat body, leg growth, and cumulative food intake of bullfrogs during the fattening phase using nonlinear models. A total of 2,375 bullfrog froglets with an initial weight of 7.03 ± 0.16 g were housed in five fattening pens (12 m²). Ten samplings were performed at intervals of 14 days to obtain the variables studied. These data were used to estimate the parameters of Gompertz and logistic models as a function of time. The estimated values of weight (Wm) and food intake (FIm) at maturity and time when the growth rate is maximum (t*) were closer to expected values when the logistic model was used. The Wm values for live weight and liver, adipose and leg weights and the FIm value for food intake were 343.7, 15.7, 19.6, 96.03 and 369.3 g, respectively, with t* at 109, 98, 105, 109 and 107 days. Therefore, the logistic model was the best model to estimate the growth and food intake of bullfrogs during the fattening phase.

INDIVIDUAL PERFORMANCE OVER TIME: GROWTH CURVE APPLICATIONS.

1991 ◽  
Vol 1991 (1) ◽  
pp. 315-319
Author(s):  
David A. Hofmann ◽  
Rick Jacobs ◽  
Steve J. Gerras
Keyword(s):  
Growth Curve ◽  
Individual Performance ◽  
Over Time

scholarly journals Evolution of communities of software: using tensor decompositions to compare software ecosystems

2019 ◽  
Vol 4 (1) ◽  
Author(s):  
Oliver A. Blanthorn ◽  
Colin M. Caine ◽  
Eva M. Navarro-López
Keyword(s):  
Dynamic Network ◽  
Tensor Decomposition ◽  
Software Projects ◽  
R Software ◽  
Tensor Decompositions ◽  
Software Ecosystems ◽  
Software Libraries ◽  
Dependency Networks ◽  
Software Packages ◽  
Over Time

AbstractModern software development is often a collaborative effort involving many authors through the re-use and sharing of code through software libraries. Modern software “ecosystems” are complex socio-technical systems which can be represented as a multilayer dynamic network. Many of these libraries and software packages are open-source and developed in the open on sites such as , so there is a large amount of data available about these networks. Studying these networks could be of interest to anyone choosing or designing a programming language. In this work, we use tensor factorisation to explore the dynamics of communities of software, and then compare these dynamics between languages on a dataset of approximately 1 million software projects. We hope to be able to inform the debate on software dependencies that has been recently re-ignited by the malicious takeover of the npm package and other incidents through giving a clearer picture of the structure of software dependency networks, and by exploring how the choices of language designers—for example, in the size of standard libraries, or the standards to which packages are held before admission to a language ecosystem is granted—may have shaped their language ecosystems. We establish that adjusted mutual information is a valid metric by which to assess the number of communities in a tensor decomposition and find that there are striking differences between the communities found across different software ecosystems and that communities do experience large and interpretable changes in activity over time. The differences between the elm and R software ecosystems, which see some communities decline over time, and the more conventional software ecosystems of Python, Java and JavaScript, which do not see many declining communities, are particularly marked.

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