Método para determinação de resíduos de clorpirifos em alface por cromatografia a líquido de alta eficiência.

Este trabalho propõe método de análise de resíduos de Clorpirifós em amostras de alface por cromatografia a líquido de alta eficiência (CLAE). A análise foi realizada em cromatógrafo Shimadzu, com detector de ultravioleta ajustado em 229 nm, Coluna C-18, modelo Zorbax ODS (4,6 mm x 25 cm, 5 um), fluxo de 1 mL/min e temperatura de 35°C. Usou-se Metanol:Água (82: 18) como fase móvel e volume injetado de 50 UL. Amostras de alface (20 g) foram trituradas e homogeneizadas na presença de 50 mL de Diclorometano (DCM). O material foi filtrado a vácuo e evaporado a temperatura de 50°C. O resíduo foi retomado com fase móvel, agitado, desgaseificado, filtrado em membrana 0,22 Um e injetado no cromatógrafo (injetor automático). Os resultados do teste de repetitividade mostraram recuperação média de 101,91 %. O método proposto é simples e rápido para determinação de resíduos de Clorpirifós em amostras de alface

Efficient plot-based floristic assessment of tropical forests

The tropical flora remains chronically understudied and the lack of floristic understanding hampers ecological research and its application for large-scale conservation planning. Given scarce resources and the scale of the challenge there is a need to maximize the efficiency of both sampling strategies and sampling units, yet there is little information on the relative efficiency of different approaches to floristic assessment in tropical forests. This paper is the first attempt to address this gap. We repeatedly sampled forests in two regions of Amazonia using the two most widely used plot-based protocols of floristic sampling, and compared their performance in terms of the quantity of floristic knowledge and ecological insight gained scaled to the field effort required. Specifically, the methods are assessed first in terms of the number of person-days required to complete each sample (‘effort’), secondly by the total gain in the quantity of floristic information that each unit of effort provides (‘crude inventory efficiency’), and thirdly in terms of the floristic information gained as a proportion of the target species pool (‘proportional inventory efficiency’). Finally, we compare the methods in terms of their efficiency in identifying different ecological patterns within the data (‘ecological efficiency’) while controlling for effort. There are large and consistent differences in the performance of the two methods. The disparity is maintained even after accounting for regional and site-level variation in forest species richness, tree density and the number of field assistants. We interpret our results in the context of selecting the appropriate method for particular research purposes

The Employment permit system and the Filipino migrant workers in Korea

Thesis(Master) --KDI School:Master of Public Policy,2013masterpublishedDela Cruz, Mary Sol Dela Pena