This study provided the basic needs of parameters estimation for nonlinear growth model such as partial derivatives of each model, determination of initial values for each parameter and statistical tests of industrial usage. Twelve nonlinear growth models and its partial derivatives for oil palm yield growth are presented in this study. The parameters are estimated using the Marquardt iterative...

A new logistic model for bacterial growth was developed in this study. The model is based on a logistic model, which is often applied for biological and ecological population kinetics. The new model is described by a differential equation and contains an additional term for suppression of the growth rate during the lag phase, compared with the original logistic equation. The new model successfu...

The Gompertz function was formulated to represent an actuarial curve, yet it often fits growth of organisms, organs and tumors. Despite numerous attempts, no consensus has been forged about the biological foundation of the broad applicability of the model. Here we revisit the Gompertzian notion of the "power to grow" and equate it with growth fraction. Aside from conferring biological interpret...

Almost perfect fits of the Gompertz equation to the growth in length of tail regenerates in the lizard, Lacerta lepida, and the newt, Notophthalmus viridescens, were obtained. Comparison of certain parameters of the equation with published mitotic index data suggests that the Gompertz equation characterizes each system at least from the time that significant mitotic activity is first observed h...

It is often necessary in applied statistical research to perform direct numerical optimization because the problem can not be transformed to be solved by standard procedures implemented in the statistical packages. One example of such a problem comes from the field of growth modeling: The Polynomial Gompertz model is known to provide a good fit to individual growth curves and growth percentiles...

A fractional factorial design was used to measure the effects and interactions of temperature (12-37 degrees C), initial pH (5.5-7.5), NaCl (0.5-4.0%) and NaNO2 (0-1000 ppm) on the anaerobic growth kinetics of Shigella flexneri in Brain-Heart Infusion broth. Anaerobic conditions were established by flushing the culture flasks with N2. A total of 375 cultures representing 124 variable combinatio...

In this communication, based upon the deterministic Gompertz growth law, a stochastic nonlinear model of tumour growth is proposed to model the conventional size-dependent therapy strategy of tumours. The probability density function of the size of the tumour obeys a nonlinear Fokker-Planck equation which can be solved analytically. It is found that during the cancer treatments the dose intensi...

Studies in the evolutionary biology of cancer research require good estimates of the intrinsic growth rate of the tumour coefficient. A Gompertzian model is a classical continuous model useful in describing population dynamics; in particular, it is a very efficient mathematical modelto describe tumour growth in humans and animals. The Gompertz survival model of a tumour growth is the interest o...

Predictions of growth are important factors that contribute to the profitability of an operation in poultry production. Modern commercial hybrids have a higher body growth in comparison with the local purebreds. However a niche market for meat and egg poultry production needs to be established using local purebreds to promote biodiversity. The aim of this study was to model the growth response ...