Evaluation of variance models for fractionator sampling of trees.

We compared the performance of several models for predicting, from small samples, the precision of estimates of the total number of blossoms on fruit trees obtained using a three-stage fractionator, in which the sampling units were defined by the tree structure: (1) primary branches and stem (2) secondary branches and shoots and (3) flowering buds. The models considered were the semiempirical models of Cruz-Orive (1990, 2004) (CO), a random sample model (SR), a Poisson model (P), successive differences (D) and repeated systematic sampling (R). Procedures that relied upon a single sample and a model of the variance (SR, P, D) were not able to predict the estimator variance because the considered structures strongly violated model assumptions.

Conservative treatment vs. mastectomy without radiotherapy in aged women with breast cancer--a prospective and randomized trial.

Objective: To determine whether tumorectomy with tamoxifen in women over 70 years achieves the same treatment results as mastectomy plus tamoxifen.

Material And Methods: Prospective randomized analysis of 121 patients over 70 with breast cancer clinically negative axilla and tumor up to 4 cm diameter. Randomization was according to even or odd birth month.