This study compared the use of various models to describe growth in lambs of 2 contrasting breeds from birth to slaughter. Live BW records (n = 7559) from 240 Texel and 231 Scottish Blackface (SBF) lambs weighed at 2-wk intervals were modeled. Biologically relevant variables were estimated for each lamb from modified versions of the logistic, Gompertz, Richards, and exponential models, and from...

Here we show that a particular one-parameter generalization of the exponential function is suitable to unify most of the popular one-species discrete population dynamics models into a simple formula. A physical interpretation is given to this new introduced parameter in the context of the continuous Richards model. From the discretization of the continuous Richards’ model (generalization of the...

The Richards equation is widely used as a model for the flow of water in unsaturated soils. For modelling one-dimensional flow in a homogeneous soil, this equation can be cast in the form of a specific nonlinear partial differential equation with a time derivative and one spatial derivative. This paper is a survey of recent progress in the pure mathematical analysis of this last equation. The e...

We present an evaluation of the laser ablation Sr isotope data reported by Richards et al. (2008) for a Neanderthal tooth recovered from a site in Greece. Based on an alternative and analytically more robust method of correcting for isobaric interferences present during the analysis the tooth appears to be isotopically homogenous and within uncertainty of the value for modern seawater. If this ...

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...

The Bertalanffy-Richards growth model is employed more than any other models for forest growth and yield modelling. However, its features have not completely been recognised. As a result, misunderstanding of the model still appears in some papers published in forest journals. A study by [1] is cited here as an evidence of the misunderstanding. This paper tries to explain different features of t...