Search results for "SPATIAL STRUCTURE"
showing 10 items of 30 documents
Determination of highly porous plastic foam structural characteristics by processing light microscopy images data
2013
Mathematical modelling of physical and mechanical properties of plastic foam as well as numerous practical applications requires knowledge of foam structural characteristics. A necessity exists to determine the characteristics of the spatial structure of inhomogeneous materials comprising inclusions of other material, e.g., polyurethane foam without destructing the material and analysis of each element. A methodology is elaborated for preparing highly porous plastic foam specimens and investigation of foam strut-like structure with light microscopy (LM) by taking images in three mutually perpendicular planes. A mathematical model is developed for highly porous plastic foam for the determina…
Molecular Rearrangement of an Aza-Scorpiand Macrocycle Induced by pH: A Computational Study †
2016
Rearrangements and their control are a hot topic in supramolecular chemistry due to the possibilities that these phenomena open in the design of synthetic receptors and molecular machines. Macrocycle aza-scorpiands constitute an interesting system that can reorganize their spatial structure depending on pH variations or the presence of metal cations. In this study, the relative stabilities of these conformations were predicted computationally by semi-empirical and density functional theory approximations, and the reorganization from closed to open conformations was simulated by using the Monte Carlo multiple minimum method Financial support by the Spanish Ministerio de Economía y Competitiv…
High-Speed and Robust Monocular Tracking
2015
In this paper, we present a system for high-speed robust monocular tracking (HSRM-Tracking) of active markers. The proposed algorithm robustly and accurately tracks multiple markers at full framerate of current high-speed cameras. For this, we have developed a novel, nearly co-planar marker pattern that can be identified without initialization or incremental tracking. The pattern also encodes a unique ID to identify different markers. The individual markers are calibrated semi-automatically, thus no time-consuming and error-prone manual measurement is needed. Finally we show that the minimal spatial structure of the marker can be used to robustly avoid pose ambiguities even at large distanc…
Expansion of SN 1993J: New λλ6 and 13 cm images
1997
Abstract Radio supernovae are rare events among supernovae, usually taking place in distant galaxies. In recent years, great progress has been made in the study of radio supernovae with high angular resolution, due to advances in the VLBI technique and to the lucky occurrence of the powerful supernova SN 1993J in M81 only 3.6 Mpc distant. Its spatial structure has been unveiled and its expansion rate determined at 3.6 cm. Here we present new preliminary VLBI results on the expansion of this supernova at 6 and 13 cm. We resolve the shell at both wavelengths. The size estimates at 6 cm indicate a lower expansion rate than previously estimated. This may be the first evidence of deceleration.
Modeling Forest Tree Data Using Sequential Spatial Point Processes
2021
AbstractThe spatial structure of a forest stand is typically modeled by spatial point process models. Motivated by aerial forest inventories and forest dynamics in general, we propose a sequential spatial approach for modeling forest data. Such an approach is better justified than a static point process model in describing the long-term dependence among the spatial location of trees in a forest and the locations of detected trees in aerial forest inventories. Tree size can be used as a surrogate for the unknown tree age when determining the order in which trees have emerged or are observed on an aerial image. Sequential spatial point processes differ from spatial point processes in that the…
A spatial analysis of new business formation: Replicative vs innovative behaviour
2017
Abstract Using spatial econometric tools, the paper examines the spatial structure of new business formation of Italian regions during the period 2004–2007. In particular, the study empirically investigates whether new business formation in a given geographical area may be explained in terms of replicative and/or innovative entrepreneurial behaviour in each area as well as in the neighbouring areas. Additionally, the analysis focuses on the influence of urbanization on the birth of new firms. From the estimation of a Spatial Durbin Model, we find a significant degree of spatial dependence among Italian regions not only in new business formation but also in some of its determinants. We also …
A spatial analysis of Italian unemployment differences
2008
Using spatial econometric models, this paper focuses attention on the spatial structure of provincial unemployment disparities of Italian provinces for the year 2003. On the basis of findings from the economic literature and of the available socio-economic data, various model specifications including supply- and demand-side variables are tested. Further we use ESDA analysis as equivalent to integration analysis on time series; therefore it is applied on each variable, dependent and independent, involved in the statistical model. The suggestions of ESDA lead us to the most adequate statistical model, which estimates indicate that there is a significant degree of neighbouring effect (i.e. pos…
Spatio-temporal Vegetation Recuperation after a Grassland Fire in Lithuania
2013
The aim of this work is to study the spatio-temporal effects of a grassland fire in Lithuania. Immediately after the fire, a experimental plot was designed in a east-faced slope. Vegetation cover and height were measured 10, 17, 31 and 46 days after the fire (vegetation cover was only measured until 31 days after the fire because in the last measurement campaign the plot was completely covered). The results showed that vegetation recovered very fast. Ten days after the fire vegetation cover and height distribution were heterogeneous, decreasing with the time due to vegetation spread. Vegetation recovered was specially observed between 17 and 31 days after the fire due vegetation recuperatio…
FUNCIONES NEUROPSICOLÓGICAS EN LAS HABILIDADES DE INICIO A LA LECTOESCRITURA
2016
Abstract:Numerous studies have tried to identify the set of skills and knowledge that are the basis for the development of literacy as phonological awareness, orthographic awareness and RAN. Since learning of literacy has its onset between 3 and 6 years, which is the maximum period of brain plasticity, it is clear the need to relate certain brain functions with the early onset of the skills that are the basis of its learning. Thus, the main objective of this work is the detection of neuropsychological functions that allow proper development of all those skills. Participants were 119 students who have been assessed twice, when 4 and 5 years old. The instruments used were the BIL, the Rapid A…
Spatial Bayesian Modeling Applied to the Surveys of Xylella fastidiosa in Alicante (Spain) and Apulia (Italy)
2020
The plant-pathogenic bacterium Xylella fastidiosa was first reported in Europe in 2013, in the province of Lecce, Italy, where extensive areas were affected by the olive quick decline syndrome, caused by the subsp. pauca. In Alicante, Spain, almond leaf scorch, caused by X. fastidiosa subsp. multiplex, was detected in 2017. The effects of climatic and spatial factors on the geographic distribution of X. fastidiosa in these two infested regions in Europe were studied. The presence/absence data of X. fastidiosa in the official surveys were analyzed using Bayesian hierarchical models through the integrated nested Laplace approximation (INLA) methodology. Climatic covariates were obtained from …