Nutrient density, the vitamin or mineral content of a food or diet per unit energy, has long been a useful concept in the nutritional sciences. However, few nutritionists have applied the idea in quantitative, population-based nutrition planning and assessment. This paper discusses the conceptual issues related to the calculation of a nutrient density value that, if consumed, should meet the nu...

Background and Objectives: During Ramadan, the ninth month in the Islamic calendar, Muslims abstain from eating and drinking from sunrise adhaan to sunset adhaan. This long fasting period can cause change in certain metabolic and hormonal indices and affect eating behaviors and nutrient intake. Therefore, the purpose of this study was to assess nutrient intake in fasting people in Qom, Iran. ...

We calculate values of forest carbon sequestration and nutrient recycling applying the replacement cost method. The value is then determined as the savings in costs by the replacement of more expensive abatement measures with these ecosystem services in cost-effective climate and nutrient programs. To this end, a dynamic optimization model is constructed, which accounts for uncertainty in seque...

Plankton--nutrient interaction models with both instantaneous and delayed nutrient recycling are considered. The system consists of three components: autotrophic phytoplankton, herbivorous zooplankton and dissolved limiting nutrient. Local stability of the equilibria is analysed. It is shown that the positive equilibrium loses its stability when the nutrient input concentration passes through a...