Exporting countries are concerned that sanitary standards might shield domestic industry from foreign competition. This study analyzes economic effects of changes in Western Hemisphere sanitary requirements on broiler trade in the Americas. A mathematical programming model detects that if Brazil...

For the general Gauss-Markov model with E(Y)=X[beta] and Var(Y)=V, we give a concise proof of an explicit characterization of the general nonnegative-definite covariance structure V such that the best linear unbiased estimator, weighted least-squares estimator, and least-squares estimator of...