Anthropization as a determinant factor in the genetic structure of Copernicia prunifera (Arecaceae).

This study uses ISSR molecular markers to characterize the demographic pattern, and spatial genetic structure (SGS) at different life stages of development (cohorts) in a natural population of Copernicia prunifera in the Rio Grande do Norte State, Brazil. All individuals were sampled and georeferenced in a 0.55-ha plot. The demographic analyses showed a clustered pattern in the first-distance classes and a random or segregated pattern at higher distance classes for all cohorts. Among the three studied life stages, juveniles showed the greatest value for Nei's genetic diversity index (HE = 0.369), while the lowest was found among reproductive adults (HE = 0.341). Greater genetic differentiation was found within life stages (98.61%) than among stages (1.39%). The total population (N = 161) showed positive and significant kinship in the first-distance class (12.3 m). The juveniles showed significant kinship up to 10.5 m. Non-reproductive adults had a positive kinship in the first-distance class (11.0 m) and a random distribution of genotypes in the remaining classes, while reproductive adults showed a random spatial distribution of genotypes. Tests for genetic bottleneck showed that the number of loci with excess observed heterozygosity was greater than expected. The SGS results reflected the restricted seed dispersion of the species, and the genetic bottleneck reflected the reduction of genotypes as a result of the anthropization of C. prunifera natural environments.

[Inter- and intra-observer variation in silicosis radiology]. / Variação inter e intra-observador na radiologia da silicose.

The radiologic criteria are important for the diagnosis of silicosis and must be objective. Initial radiologic changes are nonspecific and sometimes misinterpreted. We asked six Pulmonologists with distinct training in pulmonary disease to interpret 112 chest films according to a simple established protocol. No further information was given. One year later, all the observers analysed the same films over again. Then, we compared the results among the observers and between the two analysis made by the same individual. In 34 cases (30%) there was unanimity in asserting or denying the presence of micronodules and in 74 cases (66%) there was an agreement among the three more experienced observers. The intraobserver variability ranged from 8% to 40% and it was more important in the least trained observers. We concluded that when interpreting early radiologic changes in silicosis inter and intraobserver variability was elevated, more objectivity was achieved by the observers with more experience in epidemiologic studies and that we must be careful in interpreting results of epidemiologic studies concerning this matter.