Polymer-coated controlled-release fertilizers (PCFs) are the most widely used fertilizers in the production of container-grown nursery plants. The duration and magnitude of PCF nutrient release varies with product and this variation can significantly affect plant growth. Three experiments were conducted to determine the long-term nutrient release patterns of three PCFs (each with a rated longev...

In this paper we construct a mathematical model of two microbial populations competing for a single-limited nutrient with internal storage in an unstirred chemostat. First we establish the existence and uniqueness of steadystate solutions for the single population. The conditions for the coexistence of steady states are determined. Techniques include the maximum principle, theory of bifurcation...

We establish conditions which exclude periodic solutions in a simple chemostat with a single nutrient and N competing species. Growth rates are not required to be proportional to food uptake. Instead of a Lyapunov function approach, we develop and apply a multi-dimensional Bendixson-Dulac type exclusion principle based on differential forms.

We establish a general result for estimating the upper average of a continuous and bounded function over an infinite interval. As an application, we show that a previously studied model of microbial growth in a chemostat with time–varying nutrient input admits solutions (populations) that exhibit weak persistence but not weak average persistence.

Persistent nutrient excess results in a compensatory increase in the β-cell number in mammals. It is unknown whether this response occurs in nonmammalian vertebrates, including zebrafish, a model for genetics and chemical genetics. We investigated the response of zebrafish β-cells to nutrient excess and the underlying mechanisms by culturing transgenic zebrafish larvae in solutions of different...

Tissue engineering systems for orthopedic tissues, such as articular cartilage, are often based on the use of biomaterial scaffolds that are seeded with cells and supplied with nutrients or growth factors. In such systems, relationships between the functional outcomes of the engineered tissue construct and aspects of the initial system design are not well known, suggesting the use of mathematic...

The nutrient needs of athletes with Spinal Cord Injury (SCI) are dependent on their physiological alterations and training status. Limited research is available regarding dietary intake of elite athletes with SCI and possible nutrient deficiencies. Therefore, the purpose of this study was to examine dietary intake of elite athletes with SCI, and determine dietary intake inadequacies based on th...

The effect of oral co-administration of nutrients on intestinal drug absorption is a function of drug dissolution, gastrointestinal (GI) residence time and intestinal membrane transport. Nutrient effects on GI residence time may influence the availability of the drug for absorption when dissolution is rate controlling; alternatively, nutrient effects on membrane transport pathways may dictate v...