A spatial-temporal analysis at the early stages of the COVID-19 pandemic and its determinants: The case of Recife neighborhoods, Brazil.

The outbreak of COVID-19 has led to there being a worldwide socio-economic crisis, with major impacts on developing countries. Understanding the dynamics of the disease and its driving factors, on a small spatial scale, might support strategies to control infections. This paper explores the impact of the COVID-19 on neighborhoods of Recife, Brazil, for which we examine a set of drivers that combines socio-economic factors and the presence of non-stop services. A three-stage methodology was conducted by conducting a statistical and spatial analysis, including clusters and regression models. COVID-19 data were investigated concerning ten dates between April and July 2020. Hotspots of the most affected regions and their determinant effects were highlighted. We have identified that clusters of confirmed cases were carried from a well-developed neighborhood to socially deprived areas, along with the emergence of hotspots of the case-fatality rate. The influence of age-groups, income, level of education, and the access to essential services on the spread of COVID-19 was also verified. The recognition of variables that influence the spatial spread of the disease becomes vital for pinpointing the most vulnerable areas. Consequently, specific prevention actions can be developed for these places, especially in heterogeneous cities.

Análise de múltiplas imagens para detecção de bordas do Reservatório de Sobradinho, Bahia / Analysis of multiple images for edge detection of Sobradinho Reservoir, in Bahia, Brazil

RESUMO Neste trabalho, foram realizados testes de mapeamento de borda do reservatório de Sobradinho, Bahia, Brasil, com imagens TM LANDSAT-5, MDE-SRTM, borda do SRTM-SWBD e ASTER-GDEM-VNIR. A segmentação da imagem mosaicada da banda 4 do sensor TM serviu como referência comparativa de borda do reservatório de Sobradinho em relação às outras imagens; observou-se que o mais próximo era a borda SRTM-SWBD da NASA/NGA. Foram elaborados perfis altimétricos, entre as bordas MDE-SRTM, e radiométricos, na banda B4 segmentada. Constatou-se: baixa penetração do imageamento do MDE-SRTM nas reentrâncias das bordas do reservatório. Foram constatadas discrepâncias entre a borda SRTM-SWBD (SWB) e a segmentação da banda 4.

ABSTRACT Edge mapping tests of Sobradinho reservoir, Bahia, Brazil, were carried out on this work with TM Landsat-5 and MDE-SRTM images and SRTM-SWBD and ASTER-GDEM-VNIR edges. Mosaic of image segmentation band 4 TM sensor aided as comparative reference edge of the Sobradinho reservoir in relation to other images, and it was observed that the closest was the SRTM-SWBD edge of the NASA/NGA. Altimetry profiles were developed between MDE-SRTM edges, and also radiometric profiles, on the targeted band B4. It was found: low penetration of MDE-SRTM imaging in recessed edges of the reservoir, and discrepancies between the SRTM-SWBD edge (SWB) and the segmentation of the band 4.