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Registros recuperados: 17
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Análise de componentes principais de atributos químicos e físicos do solo limitantes à produtividade de grãos. Repositório Alice
SANTI, A. L.; AMADO, T. J. C.; CHERUBIN, M. R.; MARTIN, T. N.; PIRES, J. L. F.; DELLA FLORA, L. P.; BASSO, C. J..
Tipo: Artigo de periódico Palavras-chave: Análise multivariada; Variabilidade espacial; Variabilidade temporal; Zonas de manejo; Spatial variability; Temporal variability; Management zones.; Agricultura de Precisão.; Multivariate analysis; Precision agriculture..
Ano: 2012 URL: http://www.alice.cnptia.embrapa.br/alice/handle/doc/945807
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Characterising the temporal variability of the spatial distribution of animals: an application to seabirds at sea ArchiMer
Certain, Gregoire; Bellier, E; Planque, Benjamin; Bretagnolle, V.
Understanding the patterns of spatial and temporal variations in animal abundance is a fundamental question in ecology. Here, we propose a method to quantify temporal variations in animal spatial patterns and to determine the spatial scale at which such temporal variability is expressed. The methodology extends from the approach proposed by Taylor (Taylor, L. R. 1961. Aggregation, variance and the mean. Nature 189: 732-735) and relies on models of the relationship between temporal mean and variance in animal abundance. Repeated observations of the spatial distribution of populations are used to construct spatially explicit models of Taylor's power law. The resulting slope parameters of the Taylor power law provide local measures of the temporal variability...
Tipo: Text Palavras-chave: Temporal variability; Taylor's Power Law; Spatio temporal distribution; Seabirds; Scale dependence; Bay of Biscay.
Ano: 2007 URL: http://archimer.ifremer.fr/doc/2007/publication-3523.pdf
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Characterization of soil chemical properties of strawberry fields using principal component analysis Rev. Bras. Ciênc. Solo
Islabão,Gláucia Oliveira; Pinto,Marília Alves Brito; Selau,Lisiane Priscila Roldão; Vahl,Ledemar Carlos; Timm,Luís Carlos.
One of the largest strawberry-producing municipalities of Rio Grande do Sul (RS) is Turuçu, in the South of the State. The strawberry production system adopted by farmers is similar to that used in other regions in Brazil and in the world. The main difference is related to the soil management, which can change the soil chemical properties during the strawberry cycle. This study had the objective of assessing the spatial and temporal distribution of soil fertility parameters using principal component analysis (PCA). Soil sampling was based on topography, dividing the field in three thirds: upper, middle and lower. From each of these thirds, five soil samples were randomly collected in the 0-0.20 m layer, to form a composite sample for each third. Four...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Fragaria x ananassa Duch; Soil fertility; Multivariate analysis; Temporal variability.
Ano: 2013 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832013000100017
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Decadal stability in top predator habitat preferences in the Bay of Biscay ArchiMer
Lambert, C.; Authier, M.; Doray, Mathieu; Doremus, G.; Spitz, J.; Ridoux, V..
Most oceanographic systems, especially shelf ecosystems, are characterised by interannual variability in the timing, extent and intensity of their seasonal patterns. Such interannual variations have important consequences on top predator habitat preferences. Capitalising on oceanographic surveys performed every spring since 2004 in the Bay of Biscay (BoB), this study explored interannual variations in habitat preferences exhibited by five mobile top predator species: bottlenose and common dolphins, auks, fulmars and northern gannets. We expected to find species with similar habitat preferences every year or species exhibiting important variability in their habitat preferences. First, we identified with a Principal Component Analysis (PCA) three different...
Tipo: Text Palavras-chave: Habitat preference; Temporal variability; Cetaceans; Seabirds; North Atlantic; Bay of Biscay.
Ano: 2018 URL: https://archimer.ifremer.fr/doc/00431/54226/55549.pdf
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Environmental value and valuation over time AgEcon
Scheufele, Gabriela; Bennett, Jeffrey W..
Time and value are related concepts that influence human behaviour. Although classical topics in human thinking throughout the ages, few environmental economic non-market valuation studies have attempted to link the two concepts. Economists have estimated non-market environmental values in monetary terms for over 30 years. This history of valuation provides an opportunity to compare value estimates and how valuation techniques have changed over time. This research aims to compare value estimates of benefits of a protected natural area. In 1978, Nadgee Nature Reserve on the far south coast of New South Wales was the focus of the first application of the contingent valuation method in Australia. This research aims to replicate that study using both the...
Tipo: Report Palavras-chave: Environmental values; Temporal variability; Non-market valuation; Contingent valuation method; Choice experiments; Incentive compatibility; Natural resource management.; Environmental Economics and Policy; Land Economics/Use.
Ano: 2008 URL: http://purl.umn.edu/94805
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Investigating the coupling between small pelagic fish and marine top predators using data collected from ecosystem-based surveys ArchiMer
Certain, G.; Masse, Jacques; Van Canneyt, O.; Petitgas, Pierre; Doremus, G.; Santos, M. B.; Ridoux, Vincent.
The present study is a general multivariate analysis of the spatial association between small pelagic fishes and their predators (seabirds, marine mammals and fisheries), using 6 yr (18000 km) of transects surveyed in spring in the Bay of Biscay, France. We describe 4 groups of prey-predator association, with explicit distinction of prey size: (1) terns and anchovies (10 to 15 cm), (2) common dolphins, common murres, sprat and sardine (<20 cm), (3) gannets, horse mackerel and mackerel (15 to 25 cm) and (4) bottlenose dolphin, horse mackerel and mackerel (25 to 40 cm). Our analysis also illustrates the great variability in these associations, with years of strong prey-predator associations followed by years of weak relationships. The analysis allows us...
Tipo: Text Palavras-chave: Marine top predators; Small pelagic fishes; Spatial associations; Temporal variability; Pelagic ecosystem; Bay of Biscay.
Ano: 2011 URL: http://archimer.ifremer.fr/doc/00031/14257/11540.pdf
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Moisture content effect in the relationship between apparent electrical conductivity and soil attributes Agronomy
Costa, Marcelo Marques; Queiroz, Daniel Marçal de; Pinto, Francisco de Assis de Carvalho; Reis, Elton Fialho dos; Santos, Nerilson Terra.
To map the spatial variability of a field to define the variable rate application, an intensive sampling of the soil-plant system is necessary. The apparent soil electrical conductivity (ECa) has been used for soil mapping because it correlates well with soil attributes, allows for dense sampling and can be obtained at low cost. However, ECa is influenced by soil moisture content, and the variability of this attribute can reduce the reliability of the ECa maps to explain the physical and chemical soil attributes. The objective of this study was to identify conditions that maximize the correlations between the ECa and the soil attributes. The results show that the mean soil moisture content of soil sampled on different dates was correlated with the mean of...
Tipo: Info:eu-repo/semantics/article Palavras-chave: 5.03.00.00-8 precision agriculture; Temporal variability; Soil moisture content.
Ano: 2014 URL: http://periodicos.uem.br/ojs/index.php/ActaSciAgron/article/view/18342
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Short-term temporal variability of ammonium and urea uptake by Alexandrium catenella (Dinophyta) in cultures ArchiMer
Jauzein, Cecile; Collos, Yves; Garces, E; Vila, M; Maso, M.
In batch cultures of four Mediterranean strains (from France, Italy, and Spain) of Alexandrium catenella (Whedon et Kof.) Balech growing on a daily light cycle, ammonium and urea uptake were estimated by the N-15 tracer technique. Ammonium uptake could be described by Michaelis-Menten kinetics along a substrate gradient of 0.1-10 mu gat N.L-1 for the four strains, while two different patterns were observed for urea uptake with Michaelis-Menten kinetics for one strain and linear kinetics for the others. In all cases, an increase in uptake rates with time was noted over the daylight period. This trend led to a net increase in the maximum uptake rate (V-max; for saturable kinetics) and in the initial slope alpha. For ammonium, V-max increased by a factor of...
Tipo: Text Palavras-chave: Urea; Uptake kinetics; Temporal variability; Ammonium release; Ammonium; Alexandrium catenella.
Ano: 2008 URL: http://archimer.ifremer.fr/doc/2008/publication-6416.pdf
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Temporal changes in the biochemical composition of particulate organic matter sedimentation in the Bay of Banyuls-sur-Mer ArchiMer
Gremare, A; Amouroux, Jm; Charles, F; Medernach, L; Jordana, E; Nozais, C; Vetion, G; Colomines, Jc.
Gross sedimentation rates (GSRs) were monitored together with meteorological data and the main biochemical characteristics of the collected material (i.e. organic content, C, N, total proteins, carbohydrates, lipids and available proteins) over a three year cycle at a shallow station (18 m) of the Bay of Banyuls, France. GSRs were between 0.26 (11/04/92) and 317.75 gDW m(-2) d(-1) (18/02/94). They followed an annual cycle with low and relatively constant values during spring and summer and high, variable Values during fall and winter. During the study GSRs correlated poorly (state of the sea, precipitation) or even non-significantly (wind speed) with the main meteorological parameters. GSRs correlated negatively with the organic content of the material...
Tipo: Text Palavras-chave: Matière organique particulaire; Qualité; Variabilité temporelle; Zone côtière; Particulate organic matter; Quality; Temporal variability; Coastal zone.
Ano: 1998 URL: http://archimer.ifremer.fr/doc/00325/43640/43226.pdf
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Temporal variability in dissolved inorganic nitrogen fluxes at the sediment-water interface and related annual budget on a continental shelf (NW Mediterranean) ArchiMer
Denis, Lionel; Grenz, Christian; Alliot, Elisabeth; Rodier, Martine.
Sediment-water dissolved inorganic nitrogen fluxes were measured monthly between November 1997 and January 1999 at two sites on the continental shelf in the Gulf of Lions. Exchanges of ammonium, nitrate and nitrite were measured using whole core incubations performed in the laboratory at in situ temperature and in the dark;. Stations were located on the shelf and near the shelf break. Nitrate release represented the major part of total dissolved inorganic nitrogen fluxes (52-98%). At station Soft, nitrate flux doubled from winter-early spring to August (4 to 10 mu mol m(-2) h(-1)). At station R, a large increase (2 to 14 mu mol m(-2) h(-1)) was recorded between December 1997 and January 1998, after which flux tended to decrease. Ammonium flux was generally...
Tipo: Text Palavras-chave: Flux à l’interface eau–sédiment; Azote inorganique dissous; Variabilité temporelle; Cycle de l’azote; Méditerranée nord occidentale; Sediment-water flux; Dissolved inorganic nitrogen; Temporal variability; Nitrogen cycling; NW Mediterranean.
Ano: 2001 URL: http://archimer.ifremer.fr/doc/00323/43371/42839.pdf
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Temporal variability of atmospheric CO2 of the Spanish Atlantic Coast ArchiMer
Perez, Fiz F; Gago, Jesus; Alvarez, Marta; Rios, Aida F.
The variability of the molar fraction of atmospheric CO2 (xCO(2)(a)) and wind speed and direction were investigated in a coastal embayment located in the west European coast, ria de Vigo, NW Spain, along daily and seasonal time scales. Observations in the ria showed that xCO(2)(a) on a short time scale presented a much wider variability than seawater molar fraction (xCO(2)(w)), in addition, a significant covariation between xCO(2)(a) and wind was found. A sluggish atmospheric renewal due to weak winds was associated with high values of xCO(2)(a), whereas higher oceanic winds renovate the air column with more stable and constrained xCO(2)(a) values (from 350 to 370 ppm). The impact of anomalously high xCO(2)(a) on CO2 air-sea fluxes is practically not...
Tipo: Text Palavras-chave: Variabilité temporelle; CO2 atmosphérique; Échange air–mer; Côte atlantique espagnole; Temporal variability; Atmospheric CO2; Air-sea exchange; Spanish Atlantic Coast.
Ano: 2001 URL: http://archimer.ifremer.fr/doc/00322/43366/42849.pdf
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The biogeochemistry of the suboxic and anoxic zones in the cariaco basin Gayana
Scranton,Mary I; Astor,Yrene; Percy,Dane; Xiaona,Li; Xueju,Lin; Taylor,Gordon T.
A decade-long study of the Cariaco Basin has demonstrated that the suboxic interface in this system is temporally and spatially variable and that it is the home for a diverse and active microbial community. The thickness and structure of the suboxic zone appears to be primarily controlled by the physics of the basin, with oxygen containing intrusions occurring from both eastern and western sills. The microbial populations, which include both heterotrophic and chemoautotrophic micro-organisms, are actively growing at rates which cannot be supported by vertical transport of oxidants or reductants. Our studies suggest that the microbial loop depends on cycling of intermediate oxidation state sulfur species (sulfite, thiosulfate and elemental S) possibly...
Tipo: Journal article Palavras-chave: Chemoautotrophy; Sulfur; Temporal variability; Microbial loop.
Ano: 2006 URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-65382006000300017
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The impacts of short-term temporal factors on the magnitude and direction of marine protected area effects detected in reef fish monitoring ArchiMer
Powell, Abigail; Pelletier, Dominique; Jones, Timothy; Mallet, Delphine.
Marine protected areas (MPA) and in particular no-take marine reserves have been identified as important tools for the conservation of reef fish and habitats. A significant challenge of reef fish monitoring is to determine the influence of temporal factors on fish counts. Fish assemblages are dynamic and changes in activity patterns throughout the day can influence the results of surveys. While many monitoring programs account for the impacts of spatial heterogeneity on fish assemblages the effects of short-term temporal variation are less well known. In the present study, we analysed data from 197 video drops inside and outside New Caledonian MPAs and examined temporal variations in various metrics commonly used to monitor marine reserves. In addition to...
Tipo: Text Palavras-chave: Monitoring; Marine protected areas; Temporal variability; Coral reef fish.
Ano: 2016 URL: https://archimer.ifremer.fr/doc/00358/46964/46878.pdf
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The intra-annual variability of soft-bottom macrobenthos abundance patterns in the North Channel of the Seine estuary ArchiMer
Desroy, Nicolas; Janson, Anne-laure; Denis, Lionel; Charrier, Gregory; Lesourd, Sandric; Dauvin, Jean-claude.
Temporal and spatial variability of the Abra alba–Pectinaria koreni and Macoma balthica communities was examined in the northern part of the Seine estuary (North Channel) over different space and time scales in order to assess the role that the hydrologic regime and/or anthropogenic influences play in defining benthic communities over time. Sediment in the North Channel displayed strong spatial and temporal variability, sustained by intense sediment transport episodes. Total macrobenthic abundances ranged widely on the course of the year and there was no evidence of a seasonal signal for the density fluctuations, whatever the spatial scale considered. The bio-sedimentary dynamics can be divided into two periods: the first corresponds to the high flow rate...
Tipo: Text Palavras-chave: Port 2000; Anthropogenic impacts; Abra alba community; Sediment; Bentho pelagic coupling; Temporal variability.
Ano: 2007 URL: http://archimer.ifremer.fr/doc/2007/publication-2613.pdf
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The Seasonal and Inter-Annual Fluctuations of Plankton Abundance and Community Structure in a North Atlantic Marine Protected Area ArchiMer
Benedetti, Fabio; Jalabert, Laëtitia; Sourisseau, Marc; Becker, Beatriz; Cailliau, Caroline; Desnos, Corinne; Elineau, Amanda; Irisson, Jean-olivier; Lombard, Fabien; Picheral, Marc; Stemmann, Lars; Pouline, Patrick.
Marine Protected Areas have become a major tool for the conservation of marine biodiversity and resources. Yet our understanding of their efficacy is often limited because it is measured for a few biological components, typically top predators or species of commercial interest. To achieve conservation targets, marine protected areas can benefit from ecosystem-based approaches. Within such an approach, documenting the variation of plankton indicators and their covariation with climate is crucial as plankton represent the base of the food webs. With this perspective, we sought to document the variations in the emerging properties of the plankton to better understand the dynamics of the pelagic fishes, mammals and seabirds that inhabit the region. For the...
Tipo: Text Palavras-chave: Iroise Sea; Plankton; MPA; Temporal variability; Community composition; Size structure.
Ano: 2019 URL: https://archimer.ifremer.fr/doc/00490/60213/63561.pdf
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Variability patterns of microphytoplankton communities along the French coasts ArchiMer
Gailhard, Isabelle; Gros, Philippe; Durbec, Jp; Beliaeff, Benoit; Belin, Catherine; Nezan, Elisabeth; Lassus, Patrick.
Microalgal populations along French coasts (English Channel, Bay of Biscay and Mediterranean Sea) have been sampled twice a month since 1987 within the context of the French Phytoplankton and Phycotoxin Monitoring Network (REPHY). This study used these data to characterize the large-scale geographical structures of microphytoplankton communities and to determine whether 'homogeneous' geographical areas exist in which microalgal populations display similar temporal variability schemes. Once the temporal variability component shared by all sampled coastal sites was identified, the 'residual' site-specific component was analyzed. Multivariate ordination methods were used to determine seasonal and inter-annual variability. The expected-temporal pattern common...
Tipo: Text Palavras-chave: Microphytoplankton; French coast; Geographical structure; Temporal variability; RV coefficient; Multidimensional scaling.
Ano: 2002 URL: http://archimer.ifremer.fr/doc/00000/10033/7596.pdf
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Water storage variability in a vineyard soil in the southern highlands of Santa Catarina state Rev. Bras. Ciênc. Solo
Luciano,Rodrigo Vieira; Albuquerque,Jackson Adriano; Mafra,Álvaro Luiz; Costa,André da; Grah,Josué.
In the subtropical regions of southern Brazil, rainfall distribution is uneven, which results in temporal variability of soil water storage. For grapes, water is generally available in excess and water deficiency occurs only occasionally. Furthermore, on the Southern Plateau of Santa Catarina, there are differences in soil properties, which results in high spatial variability. These two factors affect the composition of wine grapes. Spatio-temporal analyses are therefore useful in the selection of cultural practices as well as of adequate soils for vineyards. In this way, well-suited areas can produce grapes with a more appropriate composition for the production of quality wines. The aim of this study was to evaluate the spatio-temporal variability of...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Cambisol; Vitis vinifera L.; Geostatistics; Spatial variability; Temporal variability.
Ano: 2014 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832014000100008
Registros recuperados: 17
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