Consistent patterns of common species across tropical tree communities

Trees structure the Earth’s most biodiverse ecosystem, tropical forests. The vast number of tree species presents a formidable challenge to understanding these forests, including their response to environmental change, as very little is known about most tropical tree species. A focus on the common species may circumvent this challenge. Here we investigate abundance patterns of common tree species using inventory data on 1,003,805 trees with trunk diameters of at least 10 cm across 1,568 locations 1–6 in closed-canopy, structurally intact old-growth tropical forests in Africa, Amazonia and Southeast Asia. We estimate that 2.2%, 2.2% and 2.3% of species comprise 50% of the tropical trees in these regions, respectively. Extrapolating across all closed-canopy tropical forests, we estimate that just 1,053 species comprise half of Earth’s 800 billion tropical trees with trunk diameters of at least 10 cm. Despite differing biogeographic, climatic and anthropogenic histories 7, we find notably consistent patterns of common species and species abundance distributions across the continents. This suggests that fundamental mechanisms of tree community assembly may apply to all tropical forests. Resampling analyses show that the most common species are likely to belong to a manageable list of known species, enabling targeted efforts to understand their ecology. Although they do not detract from the importance of rare species, our results open new opportunities to understand the world’s most diverse forests, including modelling their response to environmental change, by focusing on the common species that constitute the majority of their trees

Validação de um questionário de freqüência de consumo alimentar para população adulta Validation of a food frequency questionnaire for the adult population

OBJETIVO: Investigar a validade e a reprodutibilidade de um questionário de freqüência de consumo alimentar desenvolvido para a população adulta. MÉTODOS: Foram entrevistados, em três momentos, 69 indivíduos, de ambos os sexos, freqüentadores de restaurantes industriais em dois órgãos públicos de Brasília, Distrito Federal. Na primeira e terceira entrevistas foram aplicados um recordatório 24 horas e um questionário de freqüência de consumo alimentar, e na segunda entrevista, um recordatório 24 horas. A duração média do estudo foi de 181 dias. Macronutrientes, vitaminas A e C, cálcio, ferro, zinco, colesterol, fibras e energia total foram analisados utilizando-se os coeficientes de correlação intraclasse e de Pearson, este último na forma bruta e deatenuada. RESULTADOS: Quanto à reprodutibilidade, o questionário de freqüência de consumo alimentar obteve desempenho adequado, apresentando resultados acima de 0,7 para lipídeo, colesterol, energia e proteína. Para a validade, os melhores coeficientes deatenuados foram observados para vitamina C (r=0,66), ferro (r=0,58), proteína (r=0,55) e carboidrato (r=0,55) e os piores, para colesterol (r=0,32) e vitamina A (r=0,37). CONCLUSÃO: A obtenção de coeficientes de correlação expressivos para alguns nutrientes indica que este questionário de freqüência de consumo alimentar constitui-se em um bom instrumento de pesquisa para estudos epidemiológicos em população adulta, podendo fornecer informações importantes para a implementação de ações na área de saúde e nutrição.<br>OBJECTIVE: The aim of the present study was to investigate the validity and reproducibility of a food frequency questionnaire developed for the adult population. METHODS: Sixty-nine individuals from both genders who attended industrial restaurants from two government divisions in Brasília, Federal District, Brazil, were interviewed on three different occasions. In the first and third interviews, a 24h recall and a food frequency questionnaire were applied, and in the second interview only a 24h recall was applied. The study lasted 181 days. Macronutrients, vitamins A and C, calcium, iron, zinc, cholesterol, fibers and total energy were analyzed using the intraclass and Pearson's correlation coefficients, this last one in a crude and deattenuated manner. RESULTS: Regarding reproducibility, the food frequency questionnaire provided adequate results, presenting correlation coefficients above 0.7 for lipid, cholesterol, energy and protein. For validity, the best deattenuated coefficients were observed for vitamin C (r=0.66), iron (r=0.58), protein (r=0.55) and carbohydrate (r=0.55) and the worst for cholesterol (r=0.32) and vitamin A (r=0.37). CONCLUSION: The expressive correlation coefficients obtained for some nutrients indicates that this food frequency questionnaire constitutes a good research instrument for epidemiological studies in the adult population, as it can supply important dietary information allowing the implementation of actions in the health and nutrition areas

Prevalência de respiradores bucais em crianças de idade escolar Prevalence of mouth breathing in children from an elementary school

Pretende-se identificar a prevalência de respiradores bucais em crianças de uma escola do ensino fundamental. Foram aplicados 496 questionários aos pais ou responsáveis das crianças de 1ª à 4ª série de uma escola fundamental, para identificar respiradores bucais. O questionário incluía questões sobre hábitos, sono, comportamento, alimentação, cuidados pessoais e respiração. Para comparar as variáveis entre respiradores bucais e nasais, foi utilizado o teste de Mann-Whitney e qui-quadrado. Para medir o efeito da exposição das variáveis explicativas sobre o desfecho primário, foi utilizada regressão logística e sua magnitude foi calculada por meio do odds ratio. A significância estatística foi estipulada em 5%. A taxa de devolução dos questionários foi de 84,5%. A prevalência de respiração bucal nessa população foi 56,8%. A mediana de idade foi sete anos (6-9). Não houve diferença estatisticamente significante entre os gêneros, 49,1% masculino e 50,9% feminino. O modelo final de regressão logística identificou as variáveis baba, dorme bem (associação negativa) e ronca como fatores que predizem a ocorrência da respiração bucal. A prevalência de respiradores bucais foi semelhante à encontrada na literatura pesquisada. As variáveis babar, roncar e dormir bem (associação negativa) podem predizer a ocorrência da respiração bucal.<br>The objective of this article is to identify the prevalence of mouth breathing in children from an elementary school. 496 questionnaires were answered by 1st and 4th grade children's parents or sponsors in order to identify mouth-breathing. There were questions about habits, sleeping, behavior, eating, personal care and breathing. Mann-Whitney and the Chi-square tests were used to compare the variables between mouth-breathing and nose-breathing among the groups. To measure the exposure effect of the explanatory variables on mouse breathing, the test of logistic regression was used and its magnitude was calculated through Odds Ratio. The statistical significance was set at 5%, and the rate of returned questionnaires was 84.5%. The prevalence of the mouthbreathing over this population was 56.8%. The average age was 7 years old (6-9). There was no significant statistical difference between genders, considering 49.1% male and 50.9% female. The final model of logistic regression identified the variables dribble, sleeps well (negative association) and snores as factors that predict the occurrence of the mouth-breathing. The prevalence of mouthbreathing was similar to related in the literature. The variables dribble, sleeps well (negative association) and snores may be factors that predict the occurrence of mouth-breathing