Navegando por Assunto "Costa - Pará"

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Acesso aberto (Open Access)
Análise do padrão espectro-temporal de ambientes costeiros com imagens Landsat, Ilha de Marajó/PA.
(Universidade Federal do Pará, 2010-10-06) CARDOSO, Gustavo Freitas; SOUZA JUNIOR, Carlos Moreira de; http://lattes.cnpq.br/2090802631407077; SOUZA FILHO, Pedro Walfir Martins e; http://lattes.cnpq.br/3282736820907252
Knowledge of spatial and temporal distribution and monitoring of its dynamic evolution are the most important factors for the study and management of wetlands. The aim of this study was to characterize, to map, to compare the spectral response of coastal wetlands, as well as detect the changes on the eastern shore of Marajo, State of Pará, using images from TM Landsat-5 reflectance. To this end, the images were geometrically and radiometrically corrected. Were collected in the reference image (2008), at least 20 polygonal samples (5x5 pixels) for each type of land cover. The analysis of variance (ANOVA), Tukey HSD Test and an index of spectral separability of pairs of regions of interest (ROIs) were calculated. The mapping was generated from the supervised classification Spectral Angle Mapper, and validating data, outlined by the Confusion Matrix. Thus were recognized the following units: MAN - mangrove, MAD - degraded mangrove, PRD – beaches and dunes, VSI – initial secondary vegetation, VSA - advanced secondary vegetation, ACS – water with sediment, ASS - water without sediment, OCH - human occupation and CAM – marshes. The result of ANOVA showed that there are significant differences between the average reflectance in all classes and at least one pair of means, for all bands (1-5 and 7) image. The Tukey HSD test found that the smallest difference between two means of bands 1 and 2 occurs in pair VSAMAN, the band 3, VSI-MAN, the band 4, OCH-MAN, the band 5, OCH-PRD, and band 7, ASS-ACS. The function of spectral separability of pairs of ROIs highlighted a low value for the pair of classes OCH-CAM. The calculation accuracy of the mapping showed acceptable values. Was also applied the technique of spectral mixture model to determine the fractions – green vegetation, water and/or shade, soil and vegetation not photosynthetically active – in reflectance images in years from 1988, 1994, 1998, 2004, 2006 and 2008. The detection of changes over the years was done with the help of the tri-linear diagram of Thompson, used to analyze the evolution of Mangrove environments, Salt Marshes with a predominance of soils, Grassland Salt Marshes, Beaches and Dunes, Wet Sediment, Water with Sediment and Water without Sediment. The results showed that 80% of the samples from mangrove environment, maintained their spectral characteristics, ie, the environment has not changed over time, and that 15% of possible paths indicated a gradual change for the formation of mangrove until 2008. Of the total number of pixels analyzed for this environment, 93% corresponded to the actual mangrove, confirming a relative stability of this environment in the study area. Salt Marshes showed an unusual condition in the analysis of the image of the reference year (2008), with spectral response similar to the soil characteristics, this is not checked in years gone by. In recent years, there was a predominance of Grassland Salt Marshes. As for the environment Beaches and Dunes revealed a considerable increase of its surface (66.7%) in the 20-year period (1988-2008). Overall, the results suggest that the study area has undergone the process of progradation of sediments along the shoreline and stabilization in the increase of surface Mangrove since 2006. For the Salt Marshes detect the variations in the abundance values among the three fractions (Green Vegetation, Shade/Water, Non-photosynthetically Active Vegetation and Soil) generated by the spectral mixture model, mainly due to seasonal climate in the region. The method of change detection applied fostered the development of a model spectral dispersion diagram for coastal wetlands. This model should assist in future research about the monitoring of the impacts of the humid coastal environments from the increase in sea level, the location and spectral characterization, and change detection.
Acesso aberto (Open Access)
Diretrizes técnicas para locação de limites edificados em praias
(2010-12) NASCIMENTO, Flávio Campos do; LIMA, José Júlio Ferreira
Establishing limits for building on beach borders is important in urban intervention projects, since they separate private domain from public life. Contention walls play a crucial role by limiting the area used for building, and also by minimizing the effects of erosion and flooding in urban areas. This article analyzes case studies carried out in Praia do Amor, Outeiro island, in the Metropolitan Region of Belém, and Marudá Beach, a town in the Northeast of the state of Pará, Brazil. Based on the analysis of existing buildings in those locations, this study suggests a set of guidelines for establishing built limits on beaches. This article also provides references for additional studies required.
Acesso aberto (Open Access)
A gestão dos riscos naturais à erosão e inundação nos planos diretores de municípios da zona costeira (estado do Pará)
(Universidade Federal do Pará, 2011-10-10) ESPÍRITO SANTO, Celina Marques do; SZLAFSZTEIN, Claudio Fabian; http://lattes.cnpq.br/1348005678649555
The Para’s Coastal Zone is characterized by the complexity of their physical and social support. Its location marks the existence of natural hazards - erosion and flooding, which combined with a lack of consistent public policies makes people vulnerable and compromises their life quality. However, if the problem of natural hazards are recognized and considered by municipal administrators, mainly on issues of land use, damage and loss of life and material can be avoided. Thus, those who depend on these areas for survival can have a sustainable way of life, without been exposed to unsanitary conditions. It is considered that the instrument responsible for the urban planning of the territorial organization at a municipal level is the Municipal Master Plan. This is legal according to the Article 182o of the Federal Constitution considers it as regards the basic tool to guide development policies in cities. Considering the functions of the Municipal Master Plan and the reality of the Coastal Zone the present study is concerned with this problem, because potential natural disasters are putting human lives at stake. Thus, the main objective of this study is to analyze how the Municipal Master Plan for coastal municipalities of Pará incorporates the theme of natural hazards of erosion and flooding, and how this is reflected in public policies associated with risk management. Specific objectives include the following: I - Identify and describe the natural hazards of erosion and flooding of coastal cities in the State of Pará, and II - Review the management of natural erosion and flooding in the sectors policies of territorial organization in the Municipal Master Plan for coastal municipalities of the State of Pará. To pursue our goals, this study was developed at the towns of Belém, Bragança and Salinópolis under the following methodology: the search of the theoretical and conceptual references; the research and review of basic municipal information (MUNIC) and the Civil Defense organ reports of disasters as well, and also the appliance of an array to analyse the risks present at the municipal master plans. Although the natural hazards are largely found at this field of study, we could find very little information at the MUNIC data source related to problems such as erosion and flooding phenomenas. Through the Civil Defense organ data base, between the years of 2007 and 2010, only four towns, all of them on the shore area, had reported disasters, which only the town of Bragança was taken in consideration on this present essay. On our reviews of the cities government master plans, we found statements in total opposition of what they were supposed to be, probably as a result of a very trivial aproach of these matters on previous studies. In our pont of view, the government Master Plan is an important diagnostic tool on illustrating the city’s diagnosis on these situations, as well it should establish the guidelines supporting the land use. Knowing the risks, by identifying the hazardous conditions in areas subject to erosion and flooding, is the only way to make possible to support the government action, which have been claiming to intervene in the Coastal Zone seeking the improvement of the environmental and social conditions lived by those who inhabit the place.
Acesso aberto (Open Access)
Ultraestrutura do espermatozóide de Ucides cordatus Linnaeus (Crustacea, Ocypodidae) do litoral norte do Brasil
(2000-09) MATOS, Edilson Rodrigues; MATOS, Patrícia Santos; CORRAL, Laura Felícia Machado; AZEVEDO, Carlos José Correia de
Ultrastructure of spermatozoa of the crab Ucides cordatus Linnaeus, 1763 is described and illustrated. Three parts can be distinguished: 1. the elongate-ovoid acrosome located anteriorly; 2. the cytoplasmic region; and 3. the nuclear region. The acrosome is composed of a thick electron-dense wall and a less electron-dense subacrosomal space. The cytoplasm region connects the acrosome with the nucleus, and three arms filled with microtubules arise from this region. The nucleus is polymorphous. The spermatozoon of Ucides cordatus follows the general pattern described for other Decapods.