The rainy season increases the abundance and richness of the aquatic insect community in a Neotropical reservoir / Período chuvoso aumenta a abundância e riqueza da comunidade de insetos aquáticos em um reservatório neotropical

Alterations in aquatic systems and changes in water levels, whether due to rains or dam-mediated control can cause changes in community structure, forcing the community to readjust to the new environment. This study tested the hypothesis that there is an increase in the richness and abundance of aquatic insects during the rainy season in the Serra da Mesa Reservoir, with the premise that increasing the reservoir level provides greater external material input and habitat diversity, and, therefore, conditions that promote colonization by more species. We used the paired t test to test the differences in richness, beta diversity, and abundance, and a Non-metric Multidimensional Scaling (NMDS) was performed to identify patterns in the community under study. Additionally, Pearson correlations were analyzed between the richness, abundance, and beta diversity and the level of the reservoir. We collected 35,028 aquatic insect larvae (9,513 in dry period and 25,515 in the rainy season), predominantly of the Chironomidae family, followed by orders Ephemeroptera, Trichoptera, and Odonata. Among the 33 families collected, only 12 occurred in the dry season, while all occurred in the rainy season. These families are common in lentic environments, and the dominance of Chironomidae was associated with its fast colonization, their behavior of living at high densities and the great tolerance to low levels of oxygen in the environment. The hypothesis was confirmed, as the richness, beta diversity, and abundance were positively affected by the increase in water levels due to the rainy season, which most likely led to greater external material input, greater heterogeneity of habitat, and better conditions for colonization by several families.

Alterações nos sistemas aquáticos, bem como variações nos níveis da água, sejam devido a chuvas ou pelo controle exercido pela barragem podem provocar mudanças na estruturação das comunidades fazendo com que as mesmas sejam obrigadas a se readequar às novas características do ambiente. Este estudo testou a hipótese de que ocorre aumento na riqueza e abundância de insetos aquáticos na estação chuvosa no reservatório de Serra da Mesa com a premissa que o aumento do nível do reservatório proporciona maior entrada de material alóctone, maior diversidade de habitats e, consequentemente, condições para a colonização de mais espécies. Para testar as diferenças na riqueza, diversidade beta e abundância foi utilizado o test t pareado e, além disso, foi feita uma NMDS para identificar padrões na comunidade em estudo. Foram coletados 35.028 larvas de insetos aquáticos (9513 no período seco e 25.515 no período de cheia) com predominância da família Chironomidae seguida das famílias Ephemeroptera, Trichoptera e Odonata. Dentre as 33 famílias coletadas, apenas 12 ocorreram no período de seca, enquanto todas ocorreram no período chuvoso. Essas famílias são bastante encontradas em ambientes lênticos e a dominância de Chironomidae está associada ao seu rápido processo de colonização, ao seu comportamento de viver em altas densidades e sua grande tolerância a baixos teores de oxigênio no ambiente. A hipótese testada foi corroborada visto que a riqueza, a diversidade beta e a abundância de insetos aquáticos foram influenciadas positivamente pelo aumento do nível da água, decorrente do período chuvoso, que, provavelmente, propiciou uma maior entrada de material alóctone, maior heterogeneidade de habitat e melhores condições para a colonização das diversas famílias.

Evaluation of the agreement by examiners according to classifications of third molars.

OBJECTIVES: This study recorded and evaluated the intra- and inter-group agreement degree by different examiners for the classification of lower third molars according to both the Winter's and Pell & Gregory's systems. STUDY DESIGN: An observational and cross-sectional study was realized with forty lower third molars analyzed from twenty digital panoramic radiographs. Four examiner groups (undergraduates, maxillofacial surgeons, oral radiologists and clinical dentists) from Aracaju, Sergipe, Brazil, classified them in relation to angulation, class and position. The variance test (ANOVA) was applied in the examiner findings with significance level of p<0.05 and confidence intervals of 95%. RESULTS: Intra- and inter-group agreement was observed in Winter's classification system among all examiners. Pell & Gregory's classification system showed an average intra-group agreement and a statistical significant difference to position variable in inter-group analysis with greater disagreement to the clinical dentists group (p<0.05). CONCLUSIONS: High reproducibility was associated to Winter's classification, whereas the system proposed by Pell & Gregory did not demonstrate appropriate levels of reliability.