Geographic information system and multilevel analysis: gingival status among 12-year-old schoolchildren in São Paulo, Brazil.

Objective: To evaluate gingival and calculus status among schoolchildren 12 years of age using a geographic information system and multilevel analysis.

Methods: A total of 1 002 schoolchildren were selected from 18 municipal districts by means of cluster sampling, from among 25 public and private schools in Piracicaba, São Paulo, Brazil, in 2005. Examinations were carried out by a single calibrated examiner utilizing the criteria of the World Health Organization, as well as the Community Periodontal Index.

Large woody debris input and its influence on channel structure in agricultural lands of Southeast Brazil.

Riparian forests are important for the structure and functioning of stream ecosystems, providing structural components such as large woody debris (LWD). Changes in these forests will cause modifications in the LWD input to streams, affecting their structure. In order to assess the influence of riparian forests changes in LWD supply, 15 catchments (third and fourth order) with riparian forests at different conservation levels were selected for sampling.