Search results for "Spatial Analysi"
showing 10 items of 208 documents
Spatial noise-aware temperature retrieval from infrared sounder data
2020
In this paper we present a combined strategy for the retrieval of atmospheric profiles from infrared sounders. The approach considers the spatial information and a noise-dependent dimensionality reduction approach. The extracted features are fed into a canonical linear regression. We compare Principal Component Analysis (PCA) and Minimum Noise Fraction (MNF) for dimensionality reduction, and study the compactness and information content of the extracted features. Assessment of the results is done on a big dataset covering many spatial and temporal situations. PCA is widely used for these purposes but our analysis shows that one can gain significant improvements of the error rates when using…
Species richness of migratory birds is influenced by global climate change
2007
Aim Global climate change is increasingly influencing ecosystems. Long-term effects on the species richness and composition of ecological communities have been predicted using modelling approaches but, so far, hardly demonstrated in the field. Here, we test whether changes in the composition of bird communities have been influenced by recent climate change. Location Europe. Methods We focus on the proportion of migratory and resident bird species because these groups are expected to respond differently to climatic change. We used the spatial relationship between climatic factors and bird communities in Europe to predict changes in 21 European bird communities under recent climate change.…
A Spatial Econometric Analysis of Convergence Across European Regions, 1980–1995
2003
The convergence of European regions has been largely discussed in the macroeconomic and the regional science literature during the past decade. Two observations are often emphasized. First, the convergence rate among European regions appears to be very slow in the extensive samples considered (Barro and Sala-iMartin 1991, 1995; Armstrong 1995a; Sala-i-Martin 1996a, 1996b). Second, as shown in Ertur and Le Gallo (see Chap. 2), the geographical distribution of European per capita GDP is highly clustered.
Statistical power of disease cluster and clustering tests for rare diseases: A simulation study of point sources
2012
Abstract Two recent epidemiological studies on clustering of childhood leukemia showed different results on the statistical power of disease cluster and clustering tests, possibly an effect of spatial data aggregation. Eight different leukemia cluster scenarios were simulated using individual addresses of all 1,009,332 children living in Denmark in 2006. For each scenario, a number of point sources were defined with an increased risk ratio at centroid, decreasing linearly to 1.0 at the edge; aggregation levels were administrative units of Danish municipalities and squares of 5, 12.5 and 25 km 2 . Six statistical methods were compared. Generally, statistical power decreased with increasing s…
Prevalence of aphthous stomatitis in patients with inflammatory bowel disease after the treatment with monoclonal antibodies: a systematic review and…
2022
Currently, the most frequently employed therapies in the treatment of inflammatory bowel diseases (IBD), i.e., Crohn's Disease (CD), Ulcerative Colitis (UC) or unclassified IBD (IBD-U) are monoclonal anti-TNFs and anti-integrin therapies, such as vedolizumab (VDZ). Forty-seven per cent of these patients present extra-intestinal manifestations, the second most prevalent being aphthous stomatitis (AS). The present study aims to investigate which of the two therapies is associated with a lower prevalence of AS after treatment. An electronic search of the MEDLINE (via PubMed), Web of Science, SCOPUS, LILACS and OpenGrey databases was carried out. The criteria used were those described by the PR…
Loss of spatial learning in a patient with topographical disorientation in new environments
2003
The case is described of a patient who, following cerebral hypoxia, developed severe difficulty in orienting himself in new environments in the context of a mild global amnesic syndrome. Some episodes he related suggested that his main difficulty was remembering the spatial/directional value of landmarks he recognised. A neuroradiological examination documented severe bilateral atrophy of the hippocampi associated with atrophic changes in the cerebral hemispheres, most marked in the dorsal regions. Neuropsychological and experimental evaluation showed a severe deficit of spatial learning with substantially preserved ability to learn verbal and visual-object information. He was also virtuall…
Processing of 3D Models for Networking of CH in Geomatics
2020
In recent times the possibility of reconstruction of complex 3D Cultural Heritage (CH) environments has opened new scenarios for touristic and scientific aims. The different needs for networking or conservation purposes of CH lead to study proper structuring of 3D models. In light of this, a scientific approach has been developed in order to test the networking capabilities, comparing different loading configurations of 3D environments with multiple combinations of 3D models inside them, considering different solutions. This experimentation has been based on WebGL-HTML5 technologies and allowed to discover the true balance between performances of proposed system, the quality of visualizatio…
Clustering statistics in cosmology
2002
The main tools in cosmology for comparing theoretical models with the observations of the galaxy distribution are statistical. We will review the applications of spatial statistics to the description of the large-scale structure of the universe. Special topics discussed in this talk will be: description of the galaxy samples, selection effects and biases, correlation functions, Fourier analysis, nearest neighbor statistics, Minkowski functionals and structure statistics. Special attention will be devoted to scaling laws and the use of the lacunarity measures in the description of the cosmic texture.
Application of Geostatistical Tools to the Geochemical Characterization of the Peloritani Mts (Sicily, Italy) Aquifers
2021
Sources of groundwater contaminants in inhabited areas, located in complex geo-tectonic contexts, are often deeply interlocked, thus, making the discrimination between anthropic and natural origins difficult. In this study, we investigate the Peloritani Mountain aquifers (Sicily, Italy), using the combination of probability plots with concentration contour maps to retrieve an overall view of the groundwater geo-chemistry with a special focus on the flux of heavy metals. In particular, we present a methodology for integrating spatial data with very different levels of precision, acquired before and during the “geomatic era”. Our results depict a complex geochemical layout driven by a geo-puz…