Search results for "Spatial"
showing 10 items of 2121 documents
Effets sensori-moteurs et fonctionnels à long terme d’un traitement hebdomadaire par adaptation prismatique dans la négligence : un essai randomisé e…
2015
RésuméLa négligence spatiale (NS) constitue un facteur de mauvais pronostic fonctionnel. L’adaptation à une déviation prismatique de la vision vers la droite améliore la NS. Les bases neurophysiologiques et les modalités optimales de l’adaptation prismatique (AP) restent à valider. Cette étude vise à explorer les effets sensori-moteurs, cognitifs et fonctionnels à long terme produits par une séance d’AP hebdomadaire pendant 4 semaines. Un essai monocentrique, en double insu, randomisé et contrôlé a été réalisé. Vingt patients avec NS gauche secondaire à un accident vasculaire cérébral droit ont été inclus (10 dans le groupe « prisme » et 10 dans le groupe « témoin »). Les effets sensori-mot…
Estimation of actual evapotranspiration of Mediterranean perennial crops by means of remote-sensing based surface energy balance models
2009
Abstract. Actual evapotranspiration from typical Mediterranean crops has been assessed in a Sicilian study area by using surface energy balance (SEB) and soil-water balance models. Both modelling approaches use remotely sensed data to estimate evapotranspiration fluxes in a spatially distributed way. The first approach exploits visible (VIS), near-infrared (NIR) and thermal (TIR) observations to solve the surface energy balance equation whereas the soil-water balance model uses only VIS-NIR data to detect the spatial variability of crop parameters. Considering that the study area is characterized by typical spatially sparse Mediterranean vegetation, i.e. olive, citrus and vineyards, alterna…
Semi-blind Independent Component Analysis of functional MRI elicited by continuous listening to music
2013
This study presents a method to analyze blood-oxygen-level-dependent (BOLD) functional magnetic resonance imaging (tMRI) signals associated with listening to continuous music. Semi-blind independent component analysis (ICA) was applied to decompose the tMRI data to source level activation maps and their respective temporal courses. The unmixing matrix in the source separation process of ICA was constrained by a variety of acoustic features derived from the piece of music used as the stimulus in the experiment. This allowed more stable estimation and extraction of more activation maps of interest compared to conventional ICA methods.
Salinity and Bacterial Diversity: To What Extent Does the Concentration of Salt Affect the Bacterial Community in a Saline Soil?
2014
In this study, the evaluation of soil characteristics was coupled with a pyrosequencing analysis of the V2-V3 16S rRNA gene region in order to investigate the bacterial community structure and diversity in the A horizon of a natural saline soil located in Sicily (Italy). The main aim of the research was to assess the organisation and diversity of microbial taxa using a spatial scale that revealed physical and chemical heterogeneity of the habitat under investigation. The results provided information on the type of distribution of different bacterial groups as a function of spatial gradients of soil salinity and pH. The analysis of bacterial 16S rRNA showed differences in bacterial compositi…
El SandBox, una aplicación de representación espacial de realidad aumentada de interés para el aprendizaje de la geografía
2022
La SandBox est une technologie développée par l’UC Davis qui permet de modéliser des terrains en réalité augmentée. Il s’agit d’un système permettant de sculpter dans le sable un paysage qui va être topographié par l’ordinateur. Une carte d’élévation (2D), composée de courbes et de couleurs, est projetée dans l’espace d’expérimentation (3D). L’opération se fait en direct, ce qui permet une grande interactivité. Les représentations bidimensionnelles (carte 2D) ne permettent pas toujours une bonne perception de l’espace (3D) représenté, cependant cet article souligne comment utiliser la SandBox pour pallier aux difficultés rencontrées lors de la lecture de ces représentations. Il détaille com…
Bed scouring downstream of hydraulic structures under steady flow conditions: Experimental analysis of space and time scales and implications for mat…
2011
Abstract Sediment transport and bed deformation in alluvial rivers are space and time dependent. The knowledge of the space and time scales can be helpful for the definition of predictive procedures of an alluvial reach response to changing boundary conditions. In this work, attention is paid to scouring process occurring downstream of the rigid basement of a hydraulic structure. The analysis is focused on transient bed profiles which are determined, under steady flow conditions, by a decrease of the upstream sediment transport rate. In particular, the paper is aimed at improving understanding of the space and time scales required by the alluvial system to reach the equilibrium conditions. …
Measuring soil erosion by field plots: Understanding the sources of variation
2006
Soil erosion plots of different types and sizes are widely used to investigate the geomorphological processes related to soil erosion. This field method has provided a variety of results, depending on the characteristics of the plots, on their suitability to reflect the ecosystem's characteristics and on the objectives of each particular research. The coupling of real soil loss at patch and slope scale within a landscape and the values obtained by field plots depend, among other things, on how good the methodology performs over a set of ecosystem properties, such as those related with temporal and spatial scale issues, disturbance and representation of natural conditions, and the ability to…
Proposed use of spatial mortality assessments as part of the pesticide evaluation scheme for vector control
2013
Background: The WHO Pesticide Evaluation Scheme to evaluate the efficacy of insecticides does not include the testing of a lethal effect at a distance. A tool was developed to evaluate the spatial mortality of an insecticide product against adult mosquitoes at a distance under laboratory and field conditions. Operational implications are discussed. Methods: Insecticide paint, Inesfly 5A IGR (TM), containing two organophosphates (OPs): chlorpyrifos and diazinon, and one insect growth regulator (IGR): pyriproxyfen, was the product tested. Laboratory tests were performed using "distance boxes" with surfaces treated with one layer of control or insecticide paint at a dose of 1 kg/6 sq m. Field …
Long-term characterization of trihalomethane levels in drinking water
2010
Water chlorination leads to the formation of trihalomethanes (THM). In this case study, the levels of THM during the chlorination process of the drinking water in Valencia (Spain) were determined over a 12-year period. Different control areas and points were strategically sampled and samples were analyzed by gas chromatography. Temporal tendencies, as well as spatial and seasonal variations, were established. The individual distribution of THM was also evaluated. Factors such as distances from chlorination points and inter-month seasonal distribution, including ambient temperature effect, were assessed. The range of total THM concentrations measured in the water network goes from 4 to 184 µ…
Minimum contrast for point processes' first-order intensity estimation
2023
In this paper, we exploit some theoretical results, from which we know the expected value of the K-function weighted by the true first-order intensity function of a point pattern. This theoretical result can serve as an estimation method for obtaining the parameter estimates of a specific model, assumed for the data. The only requirement is the knowledge of the first-order intensity function expression, completely avoiding writing the likelihood, which is often complex to deal with in point process models. We illustrate the method through simulation studies for spatio-temporal point processes.