Comparison of the linear coefficients from the regression analysis of 307 blast (Pyricularia grisea) disease progress curves of 42 rice genotypes, tested over a period of nine seasons, were made by fitting into the logistic and Gompertz models. The regression parameters Yintercept (a), regression coefficient (b), its standard error (SEb), coefficient of determination (R) and the time required f...

the performance of different yield loss models from an exponential family was evaluated in safflower-redroot pigweed systems in two field experiments conducted during 2007 and 2008 growing seasons at the research field of agricultural college of shiraz university, iran. the yield loss of safflower was recorded as relative yield loss in experimental plots laid out in split plot design with three...

This study was conducted to describe the growth pattern of the French guinea fowl, a meat-type variety. Using BW data from hatch to 9 wk, 2 nonlinear mathematical functions (Gompertz and logistic) were used to estimate growth patterns of the French guinea fowl. The French guinea fowl did not exhibit sexual dimorphism for growth characteristics. From the Gompertz model, the asymptotic BW, growth...

The logistic, Gompertz, Richards and asymmetric logistic growth curve models were fitted to body weight data of local Ghanaian chickens and French SASSO T44 chickens. All four growth models provided good fit for each sex by genotype growth data with R2 values ranging from 86.7% to 96.7%. The rate constant parameter, k, ranged between 0.137 and 0.271 and were significantly different from zero fo...

the logistic, gompertz, richards and asymmetric logistic growth curve models were fitted to body weight data of local ghanaian chickens and french sasso t44 chickens. all four growth models provided good fit for each sex by genotype growth data with r2 values ranging from 86.7% to 96.7%. the rate constant parameter, k, ranged between 0.137 and 0.271 and were significantly different from zero fo...

A new Faustmann optimal rotation harvesting stands’ problem under Brown geometric price and Logistic and Gompertz wood stock, diffusions is presented. The optimal cut policies for the stochastic Faustmann model and the single harvest rotation or Vicksell model are evaluated in the case of a Chilean Radiata pine forest company. The company cut policy validates the Vicksell model, its optimal cut...

Logistic and Gompertz growth equations are the usual choice to model sustainable immoderate causing depletion of resources, respectively. Observing that logistic distribution is geo-max-stable function proportional Gumbel max-stable distribution, we investigate other models either distributions (log-logistic backward log-logistic) or (Fréchet max-Weibull). We show former arise when in hyper-log...

This study was undertaken to describe the growth pattern of the pearl gray Guinea fowl. Using BW data from hatch to 22 wk, 3 nonlinear mathematical functions (Richards, Gompertz, and logistic) were used to estimate growth patterns of the pearl gray guinea fowl. The logistic and Gompertz models are a special case of the Richards model, which has a variable point of inflection defined by the shap...

Experimental data of different animals (e.g. cocks, pigs, cats, dogs, cattles, etc.) from recent bibliography were selected to evaluate the capability of five classical sigmoidal equations (i.e. Bertalanffy, Weibull, logistic, Gompertz, and modified Hill) to model growth. These functions were used in different reparameterized forms in order to define all growth phases and to characterize signif...