An ecosystem-based composite spatial model for floodplain vulnerability assessment: a case study of Artigas,Uruguay     

Freitas  Gabriel  Díaz  Ismael  Bessonart  Martín  da Costa  Edwin  Achkar  Marcel 《GeoJournal》2021,86(3):1155-1171

Floods are natural processes that constitute a hazard to society when associated to improper land use. Anthropic activities in floodplains are a factor of vulnerability that converts a natural hazard into a threat factor, eventually leading to disaster. Nowadays, natural and social complex processes demand integrated assessments in order to improve their understanding, helping decision making over sustainable use of territory, as well as integrating society’s activity in ecosystems and potentials, restrictions and benefits that society obtain from them. In this context, the objective of this work was to build a composite vulnerability model for a floodplain under urban influence, using an integrated assessment approach. This model was based on three dimensions; threat, fragility and an ecosystem services provision. These dimensions were calculated using both primary and secondary information, and weights by specialists. Main results show that the area presents high vulnerability with an increasing gradient towards high and urbanized areas, associated with an important number and relevant ecosystem services. Also, a spatial heterogeneity of the three dimensions emerged, making evident this area’s complexity and the need of integrated assessments to approach it. The composite vulnerability model proposed presents an elevated potential for natural and social processes analysis in floodplains, which is crucial for these territory management. Moreover, these integrated dimensions could contribute to decision making in different levels, as well as generating important supplies for environmental management and land planning.

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Exploratory experiments to determine the effect of alternative operations on the efficiency of subsurface arsenic removal in rural Bangladesh     

M. M. Rahman  M. Bakker  S. C. Borges Freitas  D. van Halem  B. M. van Breukelen  K. M. Ahmed  A. B. M. Badruzzaman 《Hydrogeology Journal》2015,23(1):19-34

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Mapping impervious surfaces with the integrated use of Landsat Thematic Mapper and radar data: A case study in an urban–rural landscape in the Brazilian Amazon     

Dengsheng Lu  Guiying Li  Emilio Moran  Mateus Batistella  Corina C. Freitas 《ISPRS Journal of Photogrammetry and Remote Sensing》2011,66(6):798-808

This research explored the integrated use of Landsat Thematic Mapper (TM) and radar (i.e., ALOS PALSAR L-band and RADARSAT-2 C-band) data for mapping impervious surface distribution to examine the roles of radar data with different spatial resolutions and wavelengths. The wavelet-merging technique was used to merge TM and radar data to generate a new dataset. A constrained least-squares solution was used to unmix TM multispectral data and multisensor fusion images to four fraction images (high-albedo, low-albedo, vegetation, and soil). The impervious surface image was then extracted from the high-albedo and low-albedo fraction images. QuickBird imagery was used to develop an impervious surface image for use as reference data to evaluate the results from TM and fusion images. This research indicated that increasing spatial resolution by multisensor fusion improved spatial patterns of impervious surface distribution, but cannot significantly improve the statistical area accuracy. This research also indicated that the fusion image with 10-m spatial resolution was suitable for mapping impervious surface spatial distribution, but TM multispectral image with 30 m was too coarse in a complex urban–rural landscape. On the other hand, this research showed that no significant difference in improving impervious surface mapping performance by using either PALSAR L-band or RADARSAT C-band data with the same spatial resolution when they were used for multi-sensor fusion with the wavelet-based method.  相似文献   

Gravitational lenses in the dark Universe     

R. C. Freitas  S. V. B. Gonçalves  A. M. Oliveira 《Astrophysics and Space Science》2014,349(1):443-455

We discuss how different cosmological models of the Universe affect the probability that a background source has multiple images related by an angular distance, i.e., the optical depth of gravitational lensing. We examine some cosmological models for different values of the density parameter Ω _i : (i) the cold dark matter model, (ii) the ΛCDM model, (iii) the Bose-Einstein condensate dark matter model, (iv) the Chaplygin gas model, (v) the viscous fluid cosmological model and (vi) the holographic dark energy model by using the singular isothermal sphere (SIS) model for the halos of dark matter. We note that the dependence of the energy-matter content of the universe profoundly modifies the frequency of multiple quasar images.  相似文献   

Removal of phenolic compounds in olive mill wastewater by silica–alginate–fungi biocomposites     

K. R. Duarte  C. Justino  T. Panteleitchouk  A. Zrineh  A. C. Freitas  A. C. Duarte  T. A. P. Rocha-Santos 《International Journal of Environmental Science and Technology》2014,11(3):589-596

This study aims to attempt a treatment strategy based on fungi immobilized on silica-alginate (biocomposites) for removal of phenolic compounds in olive oil mill wastewater (OMW), OMW supplemented (OMWS) with phenolic compounds and water supplemented (WS) with phenolic compounds, thus decreasing its potential impact in the receiving waters. Active (alive) or inactive (death by sterilization) Pleurotus sajor caju was encapsulated in alginate beads. Five beads containing active and inactive fungus were placed in a mold and filled with silica hydrogel (biocomposites). The biocomposites were added to batch reactors containing the OMW, OMWS and WS. The treatment of OMW, OMWS and WS by active and inactive biocomposites was performed throughout 28 days at 25 °C. The efficiency of treatment was evaluated by measuring the removal of targeted organic compounds, chemical oxygen demand (COD) and relative absorbance ratio along the time. Active P. sajor caju biocomposites were able to remove 64.6–88.4 % of phenolic compounds from OMW and OMWS and 91.8–97.5 % in water. Furthermore, in the case of OMW there was also a removal of 30.0–38.1 % of fatty acids, 68.7 % of the sterol and 35 % of COD. The silica–alginate–fungi biocomposites showed a high removal of phenolic compounds from OMW and water. Furthermore, in the application of biocomposites to the treatment of OMW it was observed also a decrease on the concentration of fatty acids and sterols as well as a reduction on the COD.  相似文献   

Perspectives on the Impact of Short-Term Climatic Change in New Zealand     

Cr. de  Freitas 《New Zealand geographer》1987,43(3):169-176

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The angular momentum of dark haloes: merger and accretion effects     

Sébastien Peirani  Roya Mohayaee  José A. de Freitas Pacheco 《Monthly notices of the Royal Astronomical Society》2004,348(3):921-931

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Reconstructing fluvial bar surfaces from compound cross‐strata and the interpretation of bar accretion direction in large river deposits          下载免费PDF全文

Renato P. Almeida  Bernardo T. Freitas  Bruno B. Turra  Felipe T. Figueiredo  André Marconato  Liliane Janikian 《Sedimentology》2016,63(3):609-628

The interpretation of fluvial styles from the rock record is based for a significant part on the identification of different types of fluvial bars, characterized by the geometric relationship between structures indicative of palaeocurrent and surfaces interpreted as indicative of bar form and bar accretion direction. These surfaces of bar accretion are the boundaries of flood‐related bar increment elements, which are typically less abundant in outcrops than what would be desirable, particularly in large river deposits in which each flood mobilizes large volumes of sediment, causing flood‐increment boundary surfaces to be widely spaced. Cross‐strata set boundaries, on the other hand, are abundant and indirectly reflect the process of unit bar accretion, inclined due to the combined effect of the unit bar surface inclination and the individual bedform climbing angle, in turn controlled by changes in flow structure caused by local bar‐scale morphology. This work presents a new method to deduce the geometry of unit bar surfaces from measured pairs of cross‐strata and cross‐strata set boundaries. The method can be used in the absence of abundant flood‐increment bounding surfaces; the study of real cases shows that, for both downstream and laterally accreting bars, the reconstructed planes are very similar to measured bar increment surfaces.  相似文献   

Internal gravity waves in Titan's atmosphere observed by Voyager radio occultation     

Robert A. Freitas 《Icarus》1983,55(2):337-343

This paper discusses observational considerations in a search for extraterrestrial intelligence (SETI) program to detect extraterrestrial messenger probes in the solar system. Observable artifacts will most likely be found in a search space consisting of geocentric, selenocentric, Earth-Moon libration, and Earth-Moon halo orbits, which may be searched to a limiting artifact size of 1–10 m (p_v = 0.1) using existing or foreseeable instrumentation.  相似文献   

Structural framework and Mesozoic–Cenozoic evolution of Ponta Grossa Arch, Paraná Basin, southern Brazil     

Michael Strugale  Sidnei Pires Rostirolla  Fernando Mancini  Carlos Vieira Portela Filho  Francisco Jos Fonseca Ferreira  Rafael Corrêa de Freitas 《Journal of South American Earth Sciences》2007,24(2-4):203-227

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