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Registros recuperados: 12
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Caracterizacao do meio fisico da microbacia Quatro bocas, em Angelim, PE, e sua quantificacao por sistema de informacao geografica. Repositório Alice
SILVA, A. B. da; BRITES, R. S.; SOUSA, A. R. de..
Este trabalho teve por objetivos fazer a caracterizacao fisiografica da microbacia Quatro Bocas, quantificar por meio de Sistema de Informacao Geografica (SIG) as classes de ocupacao do meio fisico (area por classe de solo; area por classe de solo e declividade; area por classe de solo, de declividade e de uso atual das terras) e, paralelamente, fazer consideracoes sobre seu planejamento. Os planos de informacoes utilizados para entrada no SIG foram os mapas de solo, de declividade e de uso atual das terras (1989). Os solos apresentam uma forte deficiencia na fertilidade natural e o Podzolico Vermelho-Amarelo abruptico plintico abrange 87% da area, com 63% em relevo forte ondulado, o que favorece a erosao, impede a mecanizacao e exige cuidados especiais...
Tipo: Artigo em periódico indexado (ALICE) Palavras-chave: Classes de solo; Declividade; Uso atual das terras; Soil classes; Slope; Current land use.
Ano: 1999 URL: http://www.alice.cnptia.embrapa.br/handle/doc/87103
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Confidence intervals for rank statistics: Percentile slopes, differences, and ratios AgEcon
Newson, Roger.
I present a program, censlope, for calculating confidence intervals for generalized Theil–Sen median (and other percentile) slopes (and per-unit ratios) of Y with respect to X. The confidence intervals are robust to the possibility that the conditional population distributions of Y , given different values of X, differ in ways other than location, such as having unequal variances. censlope uses the program somersd and is part of the somersd package. censlope can therefore estimate confounder-adjusted percentile slopes, limited to comparisons within strata defined by values of confounders, or by values of a propensity score representing multiple confounders. Iterative numerical methods have been implemented in the Mata language, enabling efficient...
Tipo: Article Palavras-chave: Somersd; Censlope; ALSPAC; Robust; Confidence interval; Rank; Nonparametric; Median; Percentile; Slope; Difference; Ratio; Kendall's τ; Somers' D; Theil–Sen; Hodges–Lehmann; Confounder adjusted; Propensity score; Research Methods/ Statistical Methods.
Ano: 2006 URL: http://purl.umn.edu/119241
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Estimating potential soil erosion for environmental services in a sugarcane growing área ussing multisource remote sensing data. Repositório Alice
MULIANGA, B.; BÉGUÈ, A.; SIMÕES, M.; CLOUVEL, P.; TODOROFF, P..
Characterization of landscapes is crucial in modelling potential soil erosion to ascertain environmental services that are provided by the main land use in the ecosystem. Remote sensing techniques have proved successful in characterization of landscapes. In this study area of a rain-fed Kibos-Miwani sugar zone of Kenya, we used Normalized Difference Vegetation Index (NDVI) data extracted from satellite imagery to characterize the spatial and temporal heterogeneity of the vegetation conditions, and to model potential soil erosion. Data used included Moderate Resolution Imaging Spectroradiometer (MODIS) 250 m NDVI acquired in the period 2000 to 2012; 30 m Landsat5 time series images acquired between November 2010 and June 2011; a 30 m digital elevation model...
Tipo: Artigo em anais de congresso (ALICE) Palavras-chave: Sugarcane; Environmental service; Remote sensing; Land cover; Slope; Soil erosion; Cropping practices.
Ano: 2013 URL: http://www.alice.cnptia.embrapa.br/alice/handle/doc/981213
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Hydrate dissolution as a potential mechanism for pockmark formation in the Niger delta ArchiMer
Sultan, Nabil; Marsset, Bruno; Ker, Stephan; Marsset, Tania; Voisset, Michel; Vernant, Antoine-mathieu; Bayon, Germain; Cauquil, Eric; Adamy, J.; Colliat, J. L.; Drapeau, D..
Based on acquired geophysical, geological and geotechnical data and modeling, we suggest hydrate dissolution to cause sediment collapse and pockmark formation in the Niger delta. Very high-resolution bathymetry data acquired from the Niger delta reveal the morphology of pockmarks with different shapes and sizes going from a small ring depression surrounding an irregular floor to more typical pockmarks with uniform depression. Geophysical data, in situ piezocone measurements, piezometer measurements and sediment cores demonstrate the presence of a common internal architecture of the studied pockmarks: inner sediments rich in gas hydrates surrounded by overpressured sediments. The temperature, pressure and salinity conditions of the studied area have allowed...
Tipo: Text Palavras-chave: Methane gas hydrate; Sea floor; Marine sediments; Pore pressure; Porous media; Continental margin; Clathrate hydrate; Fluid flow; Stability; Slope.
Ano: 2010 URL: http://archimer.ifremer.fr/doc/00012/12300/9092.pdf
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Land Use, Soil Loss and Sustainable Agriculture in Rwanda AgEcon
Clay, Daniel C.; Lewis, Laurence A..
This paper demonstrates that there is relatively little association between field slope and crop cover in Rwanda, and examines the question of how this could be so in this highland African nation.
Tipo: Report Palavras-chave: Food security; Food policy; Rwanda; Soil erosion; Cropping patterns; Slope; Sustainable agriculture; Land Economics/Use; Q18.
Ano: 1996 URL: http://purl.umn.edu/55057
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Methodology for determining the suitability of land for the cultivation of highbush blueberry: a case study on a farm in Southern Chile Ciencia e Investigación Agraria
Vera,Leonardo; Montalba,René; Vieli,Lorena; Jorquera,Emilio; González,Isabel.
L. Vera, R. Montalba, L. Vieli, E. Jorquera, and I González. 2015. Methodology for determining the suitability of land for the cultivation of highbush blueberry: a case study on a farm in southern Chile. Cien. Inv. Agr. 42(3): 353-364. The selection of good planting sites is critical for the success of blueberry plantations. The objective of the present study was to identify farm territorial units suitable for the establishment and management of highbush blueberry crops on a farm in southern Chile. A farm-level characterization was developed, and districts and sites were classified according to their receptive capacity. Numerical suitability valúes were subsequently obtained for each land unit identified on the farm. Four suitability categories were...
Tipo: Journal article Palavras-chave: Landscape management; Limiting variable; PH; Receptive capacity; Slope.
Ano: 2015 URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-16202015000300004
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Paleoecological and paleoenvironmental implications of a high-density Chondrites association in slope deposits of the Neogene Santo Domingo Formation, Valdivia, south-central Chile Ameghiniana
Encinas,Alfonso; Buatois,Luis A.; Finger,Kenneth L..
Neogene marine strata of the Santo Domingo Formation crop out in the vicinity of Valdivia, south-central Chile (40°S, 73°W). The succession is characterized by dark-gray sandy siltstone with abundant Chondrites isp. The occurrence of this ichnotaxon and lower-bathyal benthic foraminifers is consistent with a slope depositional environment. The abundance of Chondrites and the low ichnodiversity reveal poorly oxygenated bottom waters. The Santo Domingo Formation most likely accumulated in fault-controlled, intraslope silled minibasins, which werw formed during a major event of Neogene subsidence of the Chilean margin.
Tipo: Info:eu-repo/semantics/article Palavras-chave: Ichnology; Trace fossils; Chondrites; Slope; Neogene; Chile.
Ano: 2008 URL: http://www.scielo.org.ar/scielo.php?script=sci_arttext&pid=S0002-70142008000100015
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Perdas de água e de sedimentos em solos sob as coberturas de pastagem e de mata nativa na sub-bacia do ribeirão das Posses, Extrema/MG. Repositório Alice
GOMES, M. A. F.; PEREIRA, L. C.; SOUZA, M. D. de; FIGUEIREDO, R. de O..
Este trabalho avalia perdas de água e de sedimentos em uma vertente com três tipos (classes) de solos representados por dois Cambissolos, dois Argissolos e dois Neossolos Litólicos, denominados de CH1, CH2, PVA1, PVA2, RL1 e RL2, sendo o primeiro sob cobertura de mata nativa, situado em cota mais elevada, com declividade de 55%, e os demais sob cobertura de pastagem em cotas inferiores, com declividades entre 53 a 19%. Uma análise comparativa entre as perdas de água, por exemplo, no período entre 25/05 e 10/12/2016, com precipitação de 649,3 mm, mostra que as maiores perdas ocorreram nos Neossolos Litólicos, com 19 e 21% de declividade, seguidos dos Argissolos com valores entre 35 e 23%. As perdas de água foram de 380,09 m3/ha (CH1), 392,49 m3/ha (CH2),...
Tipo: Artigo em anais de congresso (ALICE) Palavras-chave: Declividade; Escoamento superficial; Slope; Solo; Relação solo-água; Soil; Runoff.
Ano: 2017 URL: http://www.alice.cnptia.embrapa.br/alice/handle/doc/1085542
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Relevo digital dos municípios brasileiros. Repositório Alice
GUIMARAES, D. P.; LANDAU, E. C.; COSTA, T. C. e C. da.
The Brazilian Geodetic Network is being modified to the geocentric system since the creation of SIRGAS (Geocentric Reference System for South America), a system identical to WGS 84 (Wor/d Geodetic System /984). The availability of digital elevation models of mission SRTM (Shutt/e Radar Topography Mission) represent an important reference for the generation of standardized topographic bases of low cost in a geocentric system. The agricultural activity is closely related to relief characteristics, and the existence of a standardized base in a scale compatible with the agricultural use is fundamental for better utilization of the rural space. From SRTM information, data bases were generated including levei contours lines, slope and solar exposition for ali...
Tipo: Artigo em anais de congresso (ALICE) Palavras-chave: SRTM; Digital relief; Digital Elevation Model; Levei contour lines; Slope; Aspect solar exposition; Topography; Modelo Digital do Terreno; Relevo digital; Curvas de nivel; Declividade; Exposição solar; Topografia.
Ano: 2009 URL: http://www.alice.cnptia.embrapa.br/handle/doc/491975
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Sedimentation adjacent to atolls and volcano-cored carbonate platforms in the Mozambique Channel (SW Indian Ocean) ArchiMer
Counts, John; Jorry, Stephan; Leroux, Estelle; Miramontes, Elda; Jouet, Gwenael.
Recently acquired data from the Iles Eparses (southwestern Indian Ocean) reveal new information about the geomorphology, depositional processes, and sedimentary deposits on the slopes of atolls and atoll-like platforms. The deposits discussed here lie on the deepwater flanks of isolated, inactive volcanos that are capped by shallow, relatively flat carbonate platforms 45–210 km2 in area. Much of the slope geomorphology is controlled by the underlying volcanic edifice. Steep (~25–35°) upper slopes consist of outcrops of volcanic basement, smooth banks, failure scarps, and channels. Sedimentary features seen in the lower slope and proximal basin (2000–3500 m deep) consist of channels, levees, lobes, and mass transport deposits (MTDs). In places, channels...
Tipo: Text Palavras-chave: Atoll; Carbonate; Indian Ocean; Slope; Deepwater sediments.
Ano: 2018 URL: https://archimer.ifremer.fr/doc/00450/56136/57802.pdf
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The distribution of scleractinian corals in the Bay of Biscay, NE Atlantic ArchiMer
Reveillaud, J; Freiwald, A; Van Rooij, D; Le Guilloux, Erwan; Altuna, A; Foubert, A; Vanreusel, A; Olu, Karine; Henriet, J.
Studies on the distribution of scleractinian corals in the Bay of Biscay were relatively numerous during the nineteenth and the first half of the twentieth century. Yet, recent reports are scattered, sometimes unpublished, and therefore knowledge about the current coral occurrence in the area is limited. This study aims at compiling the available historical and more recently collected information on the occurrence of scleractinian corals in the Bay of Biscay. Data from two recent cruises are included and compared with previous explored coral sites from as early as 1830 up to 1995. A database of 347 records including 34 described species of scleractinians highlights that the slope of the Bay of Biscay is an important habitat for scleractinians. This could...
Tipo: Text Palavras-chave: Biodiversity; Bay of Biscay; Slope; Scleractinia; Cold water corals.
Ano: 2008 URL: http://archimer.ifremer.fr/doc/2008/publication-4503.pdf
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The GO4 Model in Near-Nadir Microwave Scattering From the Sea Surface ArchiMer
Boisot, Olivier; Nouguier, Frederic; Chapron, Bertrand; Guerin, Charles-antoine.
We introduce a practical and accurate model, referred to as "GO4," to describe near-nadir microwave scattering from the sea surface, and at the same time, we address the issue of the filtered mean square slope (mss) conventionally used in the geometrical optics model. GO4 is a simple correction of this last model, taking into account the diffraction correction induced by the rough surface through what we call an effective mean square curvature (msc). We evaluate the effective msc as a function of the surface wavenumber spectrum and the radar frequency and show that GO4 reaches the same accuracy as the physical optics model in a wide range of incidence and frequency bands with the sole knowledge of the mss and msc parameters. The key point is that the mss...
Tipo: Text Palavras-chave: Curvature; Geometrical optics; Near-nadir; Ocean radar sensing; Slope.
Ano: 2015 URL: http://archimer.ifremer.fr/doc/00277/38789/37537.pdf
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