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| Registros recuperados: 159 | |
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| Koubbi, Philippe; Loots, Christophe; Cotonnec, Gwenaelle; Harlay, Xavier; Grioche, Alain; Vaz, Sandrine; Martin, Canterbury Christ Church University; Walkey, Mike; Carpentier, Andre. |
| The spring distribution of larval fish stages of flatfishes in the Dover Strait (eastern English Channel) was studied in 1995 and 1999. Fish larvae were identified and sorted according to developmental stages in order to study their ontogenic distribution. The French coastal waters are characterised by an unstable tide-dependent front, which influences larval dispersion. In spring, the French coastal waters have a high phytoplanktonic production. They have higher temperatures, lower salinities and differences in current intensity compared with the central English Channel waters. Generalised Additive Models (GAM) combined with Geographic Information Systems (GIS) were used to model the potential habitats of life stages considering data from three major... |
| Tipo: Text |
Palavras-chave: English Channel; Fish larvae; Geostatistics; GIS; GAM. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-2090.pdf |
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| Samb, Birame; Petitgas, Pierre. |
| This study presents an application of the geostatistical one-dimensional (1D) transitive method for estimating the precision of acoustic pelagic abundance estimates in Senegal. In applying the method, the major problem encountered was how to take into account the temporal variability in the computation of the estimation variance. In acoustic surveys, echointegration is performed continuously along the ship's sailing track. For a survey design made of parallel transects, each transect can thus be considered as a sampling unit. By summing the density values along the transects to obtain biomass values per transect, the 2D estimation is simply reduced to a 1D estimation procedure. If the transects are equidistant, the geostatistical transitive method applied... |
| Tipo: Text |
Palavras-chave: Céostatistique; Variance; Acoustique; Abondance; Geostatistics; Variance; Acoustics; Abundance. |
| Ano: 1997 |
URL: http://archimer.ifremer.fr/doc/00188/29883/28348.pdf |
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| Guarini, Jean-marc; Blanchard, Fabian; Bacher, Cedric; Gros, Philippe; Riera, P; Richard, P; Gouleau, D; Galois, R; Prou, Jean; Sauriau, Pg. |
| Microphytobenthos plays an important role as primary producer in shallow embayments subject to a tidal regime. The present paper aims to characterize the spatial patterns of sedimentary chlorophyll a (chl a) biomass in 2 seasons in the wide intertidal mudflats of the Marennes-Oleron Bay (France); furthermore, it provides estimates of total microphytobenthic biomass. Accordingly, a systematic sampling scheme was performed in June 1995 and in January 1996. On average, biomass was higher in June (ca 120 mg chi a m(-2)) than in January (ca 85 mg chi a m(-2)). Moreover, the geostatistical analysis revealed that spatial similarities were propagated over larger distances in June (6 km) than in January (2.2 km). In order to account or this result, we suggest that... |
| Tipo: Text |
Palavras-chave: Microphytobenthos; Chlorophyll a; Spatial distribution; Geostatistics; Intertidal mudflat. |
| Ano: 1998 |
URL: http://archimer.ifremer.fr/doc/00447/55852/58117.pdf |
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| Orvain, Francis; Lefebvre, Sebastien; Montepini, J.; Sebire, M.; Gangnery, Aline; Sylvand, B.. |
| Intertidal flats of the estuarine macro-intertidal Baie des Veys (France) were investigated to identify spatial features of sediment and microphytobenthos (MPB) in April 2003. Gradients occurred within the domain, and patches were identified close to vegetated areas or within the oyster-farming areas where calm physical conditions and biodeposition altered the sediment and MPB landscapes. Spatial patterns of chl a content were explained primarily by the influence of sediment features, while bed elevation and compaction brought only minor insights into MPB distribution regulation. The smaller size of MPB patches compared to silt patches revealed the interplay between physical structure defining the sediment landscape, the biotic patches that they contain,... |
| Tipo: Text |
Palavras-chave: Benthic diatoms; Benthos; Coastal ecosystems; Intertidal flats; Baie des Veys; Normandie; Spatial pattern; Geostatistics; Kriging. |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00088/19945/17598.pdf |
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| Siqueira,Diego Silva; Marques Júnior,José; Teixeira,Daniel De Bortoli; Matias,Sammy Sidney Rocha; Camargo,Livia Arantes; Pereira,Gener Tadeu. |
| Abstract The objective of this work was to evaluate the use of magnetic susceptibility for characterizing the spatial variability of soil attributes and identifying areas with different potentials for sugarcane (Saccharum spp.) production. Samples were collected at 110 points (1 per 7 ha) in the layers of 0.00-0.20 and 0.20-0.40 m, to determine the magnetic susceptibility and physical and chemical attributes of the soil. Fiber content, sucrose polarization (POL), and sugarcane yield were determined in 33 points. The spatial variability model for magnetic susceptibility was 63 and 22% more accurate in delimiting soil potential for sugarcane production than soil physical and chemical attributes at the 0.0-0.2 and 0.2-0.4-m layers, respectively. The spatial... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Detailed mapping; Geostatistics; Indirect quantification; Pedometrics; Scaled semivariogram; Spatial correlation. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2016000901349 |
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| Batistella Pasini,Mauricio Paulo; Dal'Col Lúcio,Alessandro; Cargnelutti,Alberto Filho. |
| The objective of this work was to select semivariogram models to estimate the population density of fig fly (Zaprionus indianus; Diptera: Drosophilidae) throughout the year, using ordinary kriging. Nineteen monitoring sites were demarcated in an area of 8,200 m2, cropped with six fruit tree species: persimmon, citrus, fig, guava, apple, and peach. During a 24 month period, 106 weekly evaluations were done in these sites. The average number of adult fig flies captured weekly per trap, during each month, was subjected to the circular, spherical, pentaspherical, exponential, Gaussian, rational quadratic, hole effect, K-Bessel, J-Bessel, and stable semivariogram models, using ordinary kriging interpolation. The models with the best fit were selected by... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Zaprionus indianus; Geostatistics; Integrated pest management; Monitoring; Regionalized variables; Spatial dependence. |
| Ano: 2014 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2014000700493 |
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| Batista,Anderson Pedro Bernardina; Mello,José Márcio de; Raimundo,Marcel Régis; Scolforo,Henrique Ferraço; Reis,Aliny Aparecida dos; Scolforo,José Roberto Soares. |
| Abstract: The objective of this work was to analyze the spatial distribution and the behavior of species richness and diversity in a shrub savanna fragment, in 2003 and 2014, using ordinary kriging, in the state of Minas Gerais, Brazil. In both evaluation years, the measurements were performed in a fragment with 236.85 hectares, in which individual trees were measured and identified across 40 plots (1,000 m2). Species richness was determined by the total number of species in each plot, and diversity by the Shannon diversity index. For the variogram study, spatial models were fitted and selected. Then, ordinary kriging was applied and the spatial distribution of the assessed variables was described. A strong spatial dependence was observed between species... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Geostatistics; Shannon index; Variogram. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2016000800958 |
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| Almeida,André Quintão de; Souza,Rodolfo Marcondes Silva; Loureiro,Diego Campana; Pereira,Donizete dos Reis; Cruz,Marcus Aurélio Soares; Vieira,Jodnes Sobreira. |
| Abstract: The objective of this work was to model the spatial dependence and to map the rainfall erosivity index (EI30) in the semiarid region of Brazil. Registers of monthly erosivity from 210 rainfall stations were used, with daily time series equal to or greater than 15 years. Based on the values of the EI30, a spatial dependence model was made by adjusting the semivariogram. From the semivariogram models, erosivity isoline maps were generated with a kriging interpolator. According to the historical data series, the maximum monthly average value of the EI30 was observed in March, and the annual value ranged from 1,439 to 5,864 MJ mm ha-1 per year, classified as low and moderate, respectively. The highest EI30 values were obtained in the northern and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: EI30; Geostatistics; Northeastern Brazil; Semivariogram. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2017000600371 |
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| Pasini,Mauricio Paulo Batistella; Lúcio,Alessandro Dal’Col; Cargnelutti Filho,Alberto; Ribeiro,Ana Lúcia de Paula; Zamberlan,João Fernando; Lopes,Sidinei José. |
| Abstract: The objective of this work were to evaluate the population dynamics of the rice stem bug (Tibraca limbativentris) around and in flood irrigated rice cultivation area, to quantify the insect population flow between crops and host plants, and to determine the effect of the species, the diameter of the plant, and the distance of the host plant from the border on the rice stem bug population. The work was conducted in the 2012/2013 harvest and in the off-season, with sampling of rice, Andropogom bicornis, and Andropogon lateralis plants in six cultivated areas, in order to count the number of insects. The population density of the rice stem bug in irrigated rice and alternative host plants presents spatial and temporal dependence. In the cultivated... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Oryza sativa; Geostatistics; Population dynamics; Quiescence; Rice stem bug. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2018000300265 |
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| Vasques,Gustavo Mattos; Coelho,Maurício Rizzato; Dart,Ricardo Oliveira; Oliveira,Ronaldo Pereira; Teixeira,Wenceslau Geraldes. |
| Abstract The objective of this work was to compare ordinary kriging with regression kriging to map soil properties at different depths in a tropical dry forest area in Brazil. The 11 soil properties evaluated were: organic carbon content and stock; bulk density; clay, sand, and silt contents; cation exchange capacity; pH; water retention at field capacity and at permanent wilting point; and available water. Samples were taken from 327 sites at 0.0-0.10, 0.10-0.20, and 0.20-0.40-m depths, in a tropical dry forest area of 102 km2. Stepwise linear regression models for particle-size fractions and water retention properties had the best fit. Relief and parent material covariates were selected in 31 of the 33 models (11 properties at three depths) and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Caatinga; Digital soil mapping; Gamma radiometric survey; Geostatistics; Pedometrics. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2016000901371 |
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| ROCHA,F.C.; OLIVEIRA NETO,A.M.; BOTTEGA,E.L.; GUERRA,N.; ROCHA,R.P.; VILAR,C.C.. |
| The aim of this study was to identify and map the weed population in a no-tillage area. Geostatistical techniques were used in the mapping in order to assess this information as a tool for the localized application of herbicides. The area of study is 58.08 hectares wide and was sampled in a fixed square grid (which point spaced 50 m, 232 points) using a GPS receiver. In each point the weeds species and population were analyzed in a square with a 0.25 m2 fixed area. The species Ipomoea grandifolia, Gnaphalium spicatum, Richardia spp. and Emilia sonchifolia have presented no spatial dependence. However, the species Conyza spp., C. echinatus and E. indica have shown a spatial correlation. Among the models tested, the spherical model has shown had a better fit... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Conyza spp.; Geostatistics; Foci; No-tillage farming. |
| Ano: 2015 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-83582015000100157 |
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| Parfitt,José Maria Barbat; Timm,Luís Carlos; Pauletto,Eloy Antonio; Sousa,Rogério Oliveira de; Castilhos,Danilo Dufech; Ávila,Conceição Lagos de; Reckziegel,Nestor Luis. |
| In the areas where irrigated rice is grown in the south of Brazil, few studies have been carried out to investigate the spatial variability structure of soil properties and to establish new forms of soil management as well as determine soil corrective and fertilizer applications. In this sense, this study had the objective of evaluating the spatial variability of chemical, physical and biological soil properties in a lowland area under irrigated rice cultivation in the conventional till system. For this purpose, a 10 x 10 m grid of 100 points was established, in an experimental field of the Embrapa Clima Temperado, in the County of Capão do Leão, State of Rio Grande do Sul. The spatial variability structure was evaluated by geostatistical tools and the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Geostatistics; Soil sampling; Spatial dependence. |
| Ano: 2009 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832009000400007 |
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| Teixeira,Daniel De Bortoli; Bicalho,Elton da Silva; Panosso,Alan Rodrigo; Perillo,Luciano Ito; Iamaguti,Juliano Luciani; Pereira,Gener Tadeu; La Scala Jr,Newton. |
| The soil CO2 emission has high spatial variability because it depends strongly on soil properties. The purpose of this study was to (i) characterize the spatial variability of soil respiration and related properties, (ii) evaluate the accuracy of results of the ordinary kriging method and sequential Gaussian simulation, and (iii) evaluate the uncertainty in predicting the spatial variability of soil CO2 emission and other properties using sequential Gaussian simulations. The study was conducted in a sugarcane area, using a regular sampling grid with 141 points, where soil CO2 emission, soil temperature, air-filled pore space, soil organic matter and soil bulk density were evaluated. All variables showed spatial dependence structure. The soil CO2 emission... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Soil respiration; Geostatistics; Ordinary kriging; Sequential Gaussian simulation; Sugarcane. |
| Ano: 2012 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832012000500010 |
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| Mendonça,Patrícia Gabarra; Teixeira,Daniel De Bortoli; Moitinho,Mara Regina; Silva Junior,João Fernandes da; Oliveira,Ismênia Ribeiro de; Martins Filho,Marcílio Vieira; Marques Junior,José; Pereira,Gener Tadeu. |
| ABSTRACT The identification of erosion-susceptible areas is fundamental for the adoption of soil conservation practices. Thus, the best way to estimate the spatial pattern of soil erosion must be identified, in which the process uncertainties are also taken into consideration. The purpose of this study was to evaluate the spatial and temporal uncertainty of soil loss under two scenarios of sugarcane harvest management: green cane (GC) and burnt cane (BC). The study was carried out on a 200-ha area, in Tabapuã, São Paulo State, Brazil. A regular 626-point sampling grid was established in the area, with equidistant intervals of 50 m and a final plant density of about 3.3 samples per ha. The probability that the soil loss would exceed the tolerable limit of... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Green cane; Burnt cane; Geostatistics; Indicator kriging. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832018000100512 |
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| Registros recuperados: 159 | |
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