14 research outputs found
Mapping of summer crops in the State of Paraná, Brazil, through the 10-day spot vegetation NDVI composites
Mapeamento de culturas de verão no Estado do Paraná por meio de composições decendiais de NDVI do sensor spot vegetation
The search for low subjectivity area estimates has increased the use of remote sensing for agricultural monitoring and crop yield prediction, leading to more flexibility in data acquisition and lower costs comparing to traditional methods such as census and surveys. Low spatial resolution satellite images with higher frequency in image acquisition have shown to be adequate for cropland mapping and monitoring in large areas. The main goal of this study was to map the Summer crops in the State of Paraná, Brazil, using 10-day composition of NDVI SPOT Vegetation data for 2005/2006, 2006/2007 and 2007/2008 cropping seasons. For this, a supervised digital classification method with Parallelepiped algorithm in multitemporal RGB image composites was used, in order to generate masks of Summer cultures for each 10-day composition. Accuracy assessment was performed using Kappa index, overall accuracy and Willmott's concordance index, resulting in good levels of accuracy. This methodology allowed the accomplishment, with free and low resolution data, of the mapping of Summer cultures at State level.A busca por menor subjetividade em estimativas de área tem aumentado a utilização do sensoriamento remoto para monitoramento agrÃcola e previsão de safras, pois proporciona maior agilidade na aquisição de dados e menor custo em relação a métodos tradicionais de censos e pesquisas. Imagens de satélite de baixa resolução espacial e alta periodicidade são adequadas para o mapeamento, acompanhamento e desenvolvimento de culturas em áreas extensas. O objetivo deste trabalho foi mapear culturas de verão no Estado do Paraná por meio de composições decendiais de imagens NDVI do satélite SPOT Vegetation para safras de 2005/2006, 2006/2007 e 2007/2008. Para isso, foi utilizado um método de classificação digital supervisionada com algoritmo ParalelepÃpedo em composições RGB multitemporais das imagens, de forma a gerar máscaras das culturas de verão para cada composição decendial. A verificação da acurácia das máscaras foi realizada utilizando Ãndice Kappa, exatidão global e Ãndice de concordância de Willmott, resultando em bons Ãndices de acerto. Essa metodologia possibilitou realizar, com dados gratuitos e de baixa resolução espacial, o mapeamento de culturas de verão em nÃvel estadual.76077
Rosuvastatin Affecting Aortic Valve Endothelium to Slow the Progression of Aortic Stenosis
The Role of Coincidence-Detector Neurons in the Reliability and Precision of Subthreshold Signal Detection in Noise
DNA damage Mechanisms and principles of homology search during recombination
Homologous recombination is crucial for genome stability and for genetic exchange. Although our knowledge of the principle steps in recombination and its machinery is well advanced, homology search, the critical step of exploring the genome for homologous sequences to enable recombination, has remained mostly enigmatic. However, recent methodological advances have provided considerable new insights into this fundamental step in recombination that can be integrated into a mechanistic model. These advances emphasize the importance of genomic proximity and nuclear organization for homology search and the critical role of homology search mediators in this process. They also aid our understanding of how homology search might lead to unwanted and potentially disease-promoting recombination events