This study explores a hybrid stochastic delay Gompertz model under regime switching. It is proved that the has unique global positive solution. Suficient conditions for persistence in mean and extinction are obtained. The results show random perturbations time delays could effect of model.

t A mixture parametric model is used to analyze the changing pattern of Taiwanese mortality from 1926 to 1991. Three different age ranges are modeled as mixtures of extreme value distributions, namely the Weibull, inverse Weibull, and Gompertz distributions. The results show a significant improvement of mortality over the years.

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...

In this paper we provide an interval of existence of negative critical mortality rate parameters A and α in Gompertz survival model, in the absence of age specific mortality data. c © 2007 Elsevier Ltd. All rights reserved.

Soybean plants have limited growth with a planting period of 12 weeks, which causes the observed sample to be very small. A small soybean plant observations can bias in conclusion prediction results on growth. The purpose this study is apply bootstrap resampling technique Gompertz model overcomes residual distribution samples, research data was taken from four varieties spacing treatments, five...

A kinetic study was conducted to investigate the growth of Escherichia coli O157:H7 in mechanically-tenderized beef meat (MTBM) inoculated and internalized with a cocktail of 5 rifampicin-resistant (Rif(r)) or 3 arbitrarily selected wild-type strains of the bacteria. The storage was conducted at 5, 10, 15, 20, 25, and 37 degrees C. No growth was observed at 5 degrees C and the growth was minima...