the best quadratic unbiased estimation (bque) of variance components in the gauss-helmert model is used to combine adjustment of gps/levelling and geoid to determine the individual variance components for each of the three height types. through the research, different reasons for achievement of the negative variance components were discussed and a new modified version of the best quadratic unbi...

BACKGROUND When subjects are measured multiple times, linkage analysis needs to appropriately model these repeated measures. A number of methods have been proposed to model repeated measures in linkage analysis. Here, we focus on assessing the impact of repeated measures on the power and cost of a linkage study. METHODS We describe three alternative extensions of the variance components appro...

Variance and covariance components were estimated for yearling scrotal circumference and weaning weight from Limousin field data. Records of 8.226 bulls were used to evaluate 584 sires and 653 maternal grandsires. Data included all herdbook records of bulls with a recorded scrotal circumference and their weaning contemporaries. Analyses were performed by restricted maximum likelihood techniques...