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A simplified model for A. Niger FS3 growth during phytase formation in solid State fermentation BABT
Spier,Michele Rigon; Letti,Luiz Alberto Junior; Woiciechowski,Adenise Lorenci; Soccol,Carlos Ricardo.
A simplified model to describe fungal growth during citric pulp fermentation for phytase production was described for the first time. Experimental data for biomass growth were adjusted to classical mathematical growth models (Monod and Logistic). The Monod model predictions showed good agreement with the experimental results for biomass concentration during 96 hours of fermentation. Parameters such as yield of biomass from oxygen (Y X/O), maintenance coefficient (m) and specific growth rate (µ) were compared showing a good correlation between the data and the model. An alternative method for biomass determination in this process was developed since a great correlation was found between biomass growth and enzyme formation.
Tipo: Info:eu-repo/semantics/article Palavras-chave: Monod Model; Logistic model; Modelling; Fungal growth; Phytase formation; Citric pulp.
Ano: 2009 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132009000700020
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Adjusting the growth curve of sugarcane varieties using nonlinear models Ciência Rural
Jane,Sérgio Alberto; Fernandes,Felipe Augusto; Silva,Edilson Marcelino; Muniz,Joel Augusto; Fernandes,Tales Jesus; Pimentel,Guilherme Vieira.
ABSTRACT: Assessing sugarcane (Saccharum spp.) stalk growth helps to adequately manage the phenological stages of the crop. The aim of this study was to describe the height-growth curve of four sugarcane varieties (RB92579, RB93509, RB931530 and SP79-1011), in irrigated plant-cane and ratoon cane plantations, using the Logistic and Gompertz nonlinear models, while considering all deviations from assumptions. The model parameters were estimated based on the least squares method using the Gauss-Newton algorithm. To select the most suitable model, nonlinear measures, adjusted coefficient of determination (R2 adj), residual standard deviation (RSD), and corrected Akaike information criterion (AICc) were used. Based on the best models, stalk height growth rates...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Logistic model; Gompertz model; Growth rates.
Ano: 2020 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782020000300204
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Ajustamento de modelos não-lineares a dados de crescimento de suínos. Repositório Alice
FREITAS, A. R.; COSTA, C. N..
1983
Tipo: Artigo em periódico indexado (ALICE) Palavras-chave: Modelos logístico; Gompertz; Bertalanfly; Curvas de crescimento; Growth curves; Logistic model; Gompertz model; Bertalanffy model.
Ano: 1983 URL: http://www.alice.cnptia.embrapa.br/handle/doc/43218
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An analysis of the Peruvian jungle cocoa farmers: Acopagro cooperative vs. intermediaries – a case of study AgEcon
Higuchi, Angie; Moritaka, Masahiro; Fukuda, Susumu.
n the Peruvian jungle, there are two main cocoa marketing channels: the intermediaries and the cooperative. The Acopagro Cooperative, a Peruvian organization, for example, has contributed to the shift from illegal crops like cocoa to an alternative crop like cocoa which gives small scale farmers a sustainable welfare. A survey of 243 farmers in Juanjui, San Martin-which is the main cocoa production area in Peru-was carried out between December 2009-January 2010. This study analyzes Peruvian cocoa farmers’ socio-economic characteristics as these attributes affect their decision-making process in the cocoa commercialization for their self-improvement and evaluates if the farmers’ participation in Acopagro or not influences the increment of the cocoa...
Tipo: Journal Article Palavras-chave: Cooperative; Socio-economic characteristics; Logistic model; Multiple regression function; Cocoa production; Marketing channel; Farmers’ organization; Agribusiness; Community/Rural/Urban Development; Farm Management; GA; IN.
Ano: 2010 URL: http://purl.umn.edu/99218
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Analysis of Participation in Multifunctional Agriculture: U.S. Rice Farms AgEcon
Tur Cardona, Juan; Wailes, Eric J.; Dixon, Bruce L.; Danforth, Diana M..
Multifunctional agriculture is particularly fundamental to some working lands conservation policies and programs, such as the Environmental Quality Incentive Program (EQIP), Conservation Security Program (CSP) and Wildlife Habitat Incentive Program (WHIP). Farmers can also be engaged in providing recreational and agri-tourism services such as hunting, fishing, bird-watching, farm tours, petting zoos and hospitality services. Using the Agricultural Resource Management Survey (ARMS) we analyze factors associated with participation in conservation, recreation and agri-tourism activities as a function of farm structure, farm financial measures, production practices, and socio-demographic characteristics of the farm operator. To estimate the functional...
Tipo: Presentation Palavras-chave: Multifunctional agriculture; Agri-environmental policy; Rice; Logistic model; Agricultural and Food Policy; Community/Rural/Urban Development; Crop Production/Industries; Environmental Economics and Policy; Land Economics/Use; Q18; Q26; Q28.
Ano: 2012 URL: http://purl.umn.edu/119750
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Analysis of Participation in Multifunctional Agriculture: U.S. Rice Farms AgEcon
Tur Cardona, Juan; Wailes, Eric J.; Dixon, Bruce L.; Danforth, Diana M..
Multifunctional agriculture is particularly fundamental to some working lands conservation policies and programs, such as the Environmental Quality Incentive Program (EQIP), Conservation Security Program (CSP) and Wildlife Habitat Incentive Program (WHIP). Farmers can also be engaged in providing recreational and agri-tourism services such as hunting, fishing, bird-watching, farm tours, petting zoos and hospitality services. Using the Agricultural Resource Management Survey (ARMS) we analyze factors associated with participation in conservation, recreation and agri-tourism activities as a function of farm structure, farm financial measures, production practices, and socio-demographic characteristics of the farm operator. To estimate the functional...
Tipo: Presentation Palavras-chave: Multifunctional agriculture; Agri-environmental policy; Rice; Logistic model; Agricultural and Food Policy; Land Economics/Use; Q18; Q26; Q28.
Ano: 2012 URL: http://purl.umn.edu/119768
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Detection of determinant genes and diagnostic via Item Response Theory Genet. Mol. Biol.
Tavares,Héliton Ribeiro; Andrade,Dalton Francisco de; Pereira,Carlos Alberto de Bragança.
This work presents a method to analyze characteristics of a set of genes that can have an influence in a certain anomaly, such as a particular type of cancer. A measure is proposed with the objective of diagnosing individuals regarding the anomaly under study and some characteristics of the genes are analyzed. Maximum likelihood equations for general and particular cases are presented.
Tipo: Info:eu-repo/semantics/article Palavras-chave: Item Response Theory (IRT); Predisposition; Propensity; Logistic model.
Ano: 2004 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572004000400033
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Determination of a point sufficiently close to the asymptote in nonlinear growth functions Scientia Agricola
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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Epidemiología del variegado del chile (Capsicum annuum L.) en la región de Yurécuaro, Michoacán. Colegio de Postgraduados
Camacho Tapia, Moisés.
En los municipios de Yurécuaro y Vista Hermosa, con el objetivo de determinar el comportamiento de la epidemia del variegado del chile asociada a Candidatus Liberibacter solanacearum, se realizó un análisis espacio-temporal de dicha epidemia. Para confirmar la presencia de la bacteria, se colectaron muestras de chile con síntomas de clorosis, deformación de hojas, variegado y albinismo, además semillas de frutos de plantas en etapa de corte, también se colectó el insecto vector Bactericera cockerelli Sulc. Se realizó muestreo regional de diez parcelas de cultivo de chile en la etapa final para comparar la distribución espacial. Se realizaron mapas bidimensionales y tridimensionales, además se estimaron los índices de agregación usando los métodos de...
Palavras-chave: Candidatus Liberibacter solanacearum; Variegado de chile; Epidemia; Indice de agregación; Modelo logístico; Variegated pepper; Epidemic; Index of aggregation; Logistic model; Maestría; Fitopatología.
Ano: 2010 URL: http://hdl.handle.net/10521/211
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Epidemiología del variegado del chile (Capsicum annuum L.) en la región de Yurécuaro, Michoacán. Colegio de Postgraduados
Camacho Tapia, Moisés.
En los municipios de Yurécuaro y Vista Hermosa, con el objetivo de determinar el comportamiento de la epidemia del variegado del chile asociada a Candidatus Liberibacter solanacearum, se realizó un análisis espacio-temporal de dicha epidemia. Para confirmar la presencia de la bacteria, se colectaron muestras de chile con síntomas de clorosis, deformación de hojas, variegado y albinismo, además semillas de frutos de plantas en etapa de corte, también se colectó el insecto vector Bactericera cockerelli Sulc. Se realizó muestreo regional de diez parcelas de cultivo de chile en la etapa final para comparar la distribución espacial. Se realizaron mapas bidimensionales y tridimensionales, además se estimaron los índices de agregación usando los métodos de...
Palavras-chave: Candidatus Liberibacter solanacearum; Variegado de chile; Epidemia; Indice de agregación; Modelo logístico; Variegated pepper; Epidemic; Index of aggregation; Logistic model; Maestría; Fitopatología.
Ano: 2010 URL: http://hdl.handle.net/10521/211
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Growth in weight and of some tissues in the bullfrog: fitting nonlinear models during the fattening phase Ciência e Agrotecnologia
Pereira,Marcelo Maia; Mansano,Cleber Fernando Menegasso; Silva,Edney Pereira da; Stéfani,Marta Verardino De.
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...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Frog farming; Growth curves; Growth rate; Logistic model.
Ano: 2014 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1413-70542014000600009
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Growth modeling of castrated Brahman males raised in tropical conditions and born in different seasons Ciencia e Investigación Agraria
Miguel,José A; Melendez,Sandy J; Asenjo,Begoña; Bonilla,Luis M; Ciria,Jesús.
In this paper, parameters that describe growth, as a function of the season in which they were born (dry or rainy), are presented for males of the for males of the Brahman breed that were castrated at birth and raised in their native environment in the intense system of the Llano Venezolano. Data are presented for 1,478 Brahman males that were castrated at birth. Of these, 750 were born in the months of June and July (the rainy season) and 728 were born in January and February (the dry season). The animals born during the dry season were heavier up until the beginning of the fattening period; after weaning, the greatest average daily weight gain coincided in both groups during rainy periods when the pasture production was greater. When comparing the...
Tipo: Journal article Palavras-chave: Bertalanffy model; Brahman cattle; Brody model; Gompertz model; Growth curves; Logistic model; Richards model.
Ano: 2012 URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-16202012000200004
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Health Disparities in Rural Georgia: A Case Study of Liberty, Long, and McIntosh Counties AgEcon
Amponsah, William A.; Fuller, Whitney; Gibbison, Godfrey.
Health disparities can be defined as differences in the health status among distinct segments of the population including differences that occur by gender, race or ethnicity, education, income, disability, or living in various geographic localities. When populations are disproportionately unhealthy, they are likely to be unable to maintain steady employment, and are more likely to rely on government assistance and support from others. We conduct a case study of three rural counties; Liberty, Long, and McIntosh to explore what factors explain the incidence of health disparities manifested in high blood pressure and heart disease. We test the hypotheses that older individuals are more likely to experience illness at a higher rate than the rest of the...
Tipo: Conference Paper or Presentation Palavras-chave: Health disparities; High blood pressure; Heart disease; Rural community; Logistic model; Community/Rural/Urban Development; Health Economics and Policy; I100; I120; I180.
Ano: 2010 URL: http://purl.umn.edu/56562
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Influencing Factors of Householders’ Transferring out Cultivated Land under the Background of Urban and Rural Integration AgEcon
Zhang, Rui; Xiao, Hong-an; Zhang, Wen-xiu.
Factors influencing householders’ transferring out the cultivated land are analyzed from the aspects of farmers’ individual characteristics, farmers’ family features, resources endowment features and external environmental features. And based on the results of the questionnaire survey of 252 households in Chengdu City, the effect of each factor is analyzed through building the dual preference model of Logistic. The result shows that 65.87% of householders have transferred out their cultivated land and proportion of non-agricultural incomes, stability of land ownership, per capita area of cultivated farmland, comminution of cultivated farmland, transferring price and distance to town have relatively significant effect on farmers’ transferring out cultivated...
Tipo: Journal Article Palavras-chave: Cultivated land transference; Logistic model; Influence; China; Agribusiness.
Ano: 2011 URL: http://purl.umn.edu/113438
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Methods to verify parameter equality in nonlinear regression models Scientia Agricola
Carvalho,Lídia Raquel de; Pinho,Sheila Zambello de; Mischan,Martha Maria.
In biologic experiments, in which growth curves are adjusted to sample data, treatments applied to the experimental material can affect the parameter estimates. In these cases the interest is to compare the growth functions, in order to distinguish treatments. Three methods that verify the equality of parameters in nonlinear regression models were compared: (i) developed by Carvalho in 1996, performing ANOVA on estimates of parameters of individual fits; (ii) suggested by Regazzi in 2003, using the likelihood ratio method; and (iii) constructing a pooled variance from individual variances. The parametric tests, F and Tukey, were employed when the parameter estimators were near to present the properties of linear model estimators, that is, unbiasedness,...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Logistic model; Treatments comparison.
Ano: 2010 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162010000200014
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Mixed-effects growth curves in the valuation of Nellore sires Scientia Agricola
Giolo,Suely Ruiz; Henderson,Robin; Demétrio,Clarice Garcia Borges.
Cattle breeding programmes need objective criteria in order to evaluate and subsequently improve production systems. This work uses a logistic growth curve model for evaluating sires based on their progeny weight measured repeatedly over time. The parameters of the curve are described as a linear function of fixed and random effects. A Bayesian approach is used for the estimation. Analysis of the weights recorded on animals of the Nellore breed shows that growth curve models with fixed and random effects can be useful to evaluate and selecting sires.
Tipo: Info:eu-repo/semantics/article Palavras-chave: Beef cattle; Logistic model; Longitudinal data; Random effects.
Ano: 2009 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162009000100012
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Modeling the weight gain of freshwater-reared rainbow trout ( Oncorhynchus mykiss ) during the grow-out phase R. Bras. Zootec.
Janampa-Sarmiento,Peter Charrie; Takata,Rodrigo; Freitas,Thiago Mendes de; Freire,Licius de Sá; Pereira,Marcelo Menezes de Britto; Lugert,Vincent; Heluy,Guilherme Melgaço; Pereira,Marcelo Maia.
ABSTRACT We used five nonlinear models to calculate the weight gain of rainbow trout (122.11±15.6 g) during the final grow-out phase of 98 days under three different feed types (two commercials diets, A and B, and one experimental diet, C) in triplicate groups. We fitted the von Bertalanffy growth function with allometric and isometric scaling coefficient, Gompertz, Logistic, and Brody functions to weight (g) at age data of 900 fish, distributed in nine tanks. The equations were fitted to the data based on the least squares method using the Marquardt iterative algorithm. The accuracy of the fitted models was evaluated using a model performance metrics, combining mean squared residuals (MSR), mean absolute error (MAE), and Akaike’s Information Criterion...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Aquaculture; Logistic model; Non-linear equations; Oncorhynchus mykiss.
Ano: 2020 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982020000100200
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Nonlinear regression and plot size to estimate green beans production Horticultura Brasileira
Lucio,Alessandro DC; Nunes,Luis F; Rego,Francisco.
ABSTRACT The objectives of this work were to adjust nonlinear regression models for the green beans production and to identify the plot size which provides the best explanation and adjustment to the models. The authors used two field and two protected environment (plastic tunnel) trials in the autumn-winter and spring-summer seasons. The logistic and von Bertalanffy models were adjusted for average weight of green beans accumulated after multiple harvests and with different plot sizes. The models presented similar estimates and the same parameters estimates in all the plot sizes. The logistic model provided estimates closest to the reality, showing the best description performance for the average weight of pods during the productive cycle. In the...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Phaseolus vulgaris; Growth models; Logistic model; Von Bertalanffy model; Horticulture.
Ano: 2016 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-05362016000400507
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Soil drying and rewatering applied at three grain developmental stages affect differentially growth and grain protein deposition in wheat (Triticum aestivum L.) Braz. J. Plant Physiol.
Beltrano,José; Ronco,Marta Guillermina; Arango,María Cecilia.
Water deficits cause large yield losses in wheat. Although anthesis is generally considered the most vulnerable period, water deficit during grain filling can also cause yield losses. The objective of this study was to investigate the effect of water stress and rewatering, at three different grain developmental stages, on physiological and grain filling parameters and on yield components. Wheat plants were subjected to water deficit and rewatering at the watery ripe, milk and soft dough stages. In the flag leaf, water stress decreased the relative water content, the chlorophyll and protein content and increased the leakage of solutes, at all three studied grain filling stages. Water stress at the watery ripe and milk stages reduced the final grain dry mass...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Grain filling; Growth rate; Logistic model; Protein profile; Water stress.
Ano: 2006 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202006000200011
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The Importance Of Indigenous Biodiversity On Waikato Farms AgEcon
Trinh, Phuong Khanh; Kaval, Pamela.
In this paper, we studied the importance of indigenous biodiversity (native bush) on farm properties in the Waikato Region. To do this, we surveyed both real estate agents and farmers. We discovered that opinions of native bush between the two groups were very different. A small percentage of real estate agents believed that indigenous biodiversity on farms mattered; type of farm sold and age of respondent influenced this belief. While approximately half of Waikato farmers believed that native bush was important; this was influenced by age, income, education level, number of farm owners and sex. Farmers suggested that rates rebates, as well as subsidized planting and subsidized fencing would motivate them to plant more native bush on their lands.
Tipo: Conference Paper or Presentation Palavras-chave: Waikato; Indigenous biodiversity; Farms; Surveys; Logistic model; Agricultural and Food Policy; Community/Rural/Urban Development; Consumer/Household Economics; Environmental Economics and Policy; Farm Management; Land Economics/Use; Livestock Production/Industries.
Ano: 2005 URL: http://purl.umn.edu/98505
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