Local-scale spatial variation in diversity of social wasps in an Amazonian rain forest in Caxiuanã, Pará, Brazil (Hymenoptera, Vespidae, Polistinae)

Polistine wasps are important in Neotropical ecosystems due to their ubiquity and diversity. Inventories have not adequately considered spatial attributes of collected specimens. Spatial data on biodiversity are important for study and mitigation of anthropogenic impacts over natural ecosystems and for protecting species. We described and analyzed local-scale spatial patterns of collecting records of wasp species, as well as spatial variation of diversity descriptors in a 2500-hectare area of an Amazon forest in Brazil. Rare species comprised the largest fraction of the fauna. Close range spatial effects were detected for most of the more common species, with clustering of presence-data at short distances. Larger spatial lag effects could also be identified in some species, constituting probably cases of exogenous autocorrelation and candidates for explanations based on environmental factors. In a few cases, significant or near significant correlations were found between five species (of Agelaia, Angiopolybia, and Mischocyttarus) and three studied environmental variables: distance to nearest stream, terrain altitude, and the type of forest canopy. However, association between these factors and biodiversity variables were generally low. When used as predictors of polistine richness in a linear multiple regression, only the coefficient for the forest canopy variable resulted significant. Some level of prediction of wasp diversity variables can be attained based on environmental variables, especially vegetation structure. Large-scale landscape and regional studies should be scheduled to address this issue.

Validation procedures in radiological diagnostic models. Neural network and logistic regression

The objective of this paper is to compare the performance of twopredictive radiological models, logistic regression (LR) and neural network (NN), with five different resampling methods. One hundred and sixty-seven patients with proven calvarial lesions as the only known disease were enrolled. Clinical and CT data were used for LR and NN models. Both models were developed with cross validation, leave-one-out and three different bootstrap algorithms. The final results of each model were compared with error rate and the area under receiver operating characteristic curves (Az). The neural network obtained statistically higher Az than LR with cross validation. The remaining resampling validation methods did not reveal statistically significant differences between LR and NN rules. The neural network classifier performs better than the one based on logistic regression. This advantage is well detected by three-fold cross-validation, but remains unnoticed when leave-one-out or bootstrap algorithms are used.

GUINEA-BISSAU: The Role of Local and International NGOs in Environmental Preservation and Sustainability of the Bijagos Archipelago

Bijagos Archipelago in Guinea-Bissau is at present subject to numerous external impacts that affect its centuries old balance. Since 1975 Guinean society has been using its natural resources in an uncontrolled way over the territory and especially in the coastal area. The archipelago has been increasingly raising interest, most of which is incompatible with the guarantee for a long-term sustainable development. It has also displayed a general impoverishment as far as resource preservation is concerned, due to internal demographic pressure of a population that has doubled since 1981 and to external pressure related to neighboring migrations and consequent depletion of non-renewable resources. This article aims to analyze the actions of local and international NGOs in the preservation and sustainability of the Bijagos Archipelago. We seek through an interdisciplinary approach to analyze the phenomena that are configured within the strategies of NGOs, on the assumption that these issues are articulated in the field of geography and sociology, as well as in politics and international cooperation. It is proposed new challenges to environmental issues, especially in a current situation shaken by constant instability internal and external policies.