In this work, we focus on the mathematical analysis of the model of chemostat with enzymatic degradation of a substrate (organic matter) that can partly be under a solid form Simeonov and Stoyanov (2003). The study of this 3-step model is derived from a smaller order sub-model since some variables can be decoupled from the others. We study the existence and the stability of equilibrium points o...

Nutrient availability is one of the major factors regulating marine productivity and phytoplankton community structure. While the response of phytoplankton species to nutrient variation is relatively well known, that of phytoplankton community remains unclear. We question whether phytoplankton community growth rates respond to nutrient concentration in a similar manner to phytoplankton species ...

The phenomenon of enzyme induction (enzymatic adaptation) has been observed in a variety of micro-organisms. One of the most carefully studied examples, largely the work of Jacques Monod and his colleagues at the Institut Pasteur, is the induction of the synthesis of the enzyme j3-galactosidase in the bacterium Escherichia coli.", 2 This enzyme, not otherwise present in appreciable amounts, is ...

We examined the activation kinetics of the delayed rectifier K+ current of bullfrog sympathetic neurons, primarily using whole cell recording. On depolarization, currents activated with a sigmoid delay but did not show a Cole-Moore shift. The time course of activation differed systematically from an exponential raised to a power. At most voltages, a power of 2 gave the best overall fit but a po...