The increased interest in the variability of soil properties is responsible for recent observations that soil variables are not normally distributed but are more closely approximated by the two-parameter lognormal frequency distribution. Statistical methods commonly applied in the estimation of...

The authors build a model of child labor and study its implication for welfare and fertility. Assuming there is a trade-off between child labor and human capital accumulation, we derive conditions under which child labor is socially inefficient. Even if parents are altruistic, child labor may...

The autors study the implications of the trade-off between child quality and child quantity for the efficiency of the rate of population growth. They show that if quantity and quality are inversely related then, even in the case of full altruism within the family, population growth is...

Natural resources models serve as important tools to support decision making by predicting environmental indicators. All model predictions have uncertainty associated with them. Model predictive uncertainty, often expressed as the confidence interval around a model prediction value, may serve as...

For most irrigation systems, the most practical method for determining the global distribution uniformity (i.e., that experienced by the entire crop) is to measure the uniformity resulting from several components and combine them statistically. In this paper, procedures and equations are...

Estimation of uncertainty using agronomic models typically requires a Monte Carlo study with a large number of simulations. Parallel computation dramatically speeds repetitive computation of this sort. The use of a Beowulf cluster parallel computer offers a low cost method of parallel computing...

Although the U.S. Congress established the Total Maximum Daily Load (TMDL) program in the original Clean Water Act of 1972, Section 303(d), it did not receive attention until the 1990s. Currently, two methods are available for tracking pollution in the environment and assessing the effectiveness...