2,490 research outputs found
Norm localisation and migration laws in the Maghreb
In the 2000s, Morocco, Tunisia and Algeria have proceeded to revise their outdated laws regulating the movements of people across national borders. Such timely legislative action has been deemed to be the result of the European Union’s external policy on transferring its restrictive migration governance to neighbouring countries. The legal framework emerging from the Maghreb reforms does appear to have broadly converged towards restrictive migratory policies. However, the paper outlines how such policy convergence has been in part achieved through a localisation of international legal norms, which did not result in an approximation to international and EU law. Ultimately, the paper sets out to show how migratory laws in the Maghreb do play a part in the externalisation of the EU’s border control, but do so by actually departing from the same international and EU normative standards that the Union has been promoting to its Maghreb neighbours.Funded by the European Research Council (ERC) within the 7th Framework Programme, the BORDERLANDS project is hosted at the Robert Schuman Centre for Advanced Studies, European University Institute, and directed by Professor Raffaella A. Del Sarto
GEOGRAPHIC INFORMATION SYSTEMS ORIENTED TO IGM NETWORK
In questo lavoro presentiamo il lavoro svolto dall’IGM per la pubblicazione di una serie di
cataloghi web, volti alla divulgazione del materiale posseduto dall’istituto. La sperimentazione
delle tecnologie web-gis si è basata su software Open Source ed è servita come
punto di partenza per la realizzazione dei servizi previsti da INPIRE1.In this paper we present the publication of a set of web-catalogs, referring to geographic
information of IGM. The used technology is Open Source and it works as
experimentation of INSPIRE project
Preserving attribute values on simplified meshes by re-sampling detail textures
Many sophisticated solutions have been proposed to reduce the geometric complexity of 3D meshes. A slightly less studied problem is how to preserve attribute detail on simplified meshes (e.g., color, high-frequency shape details, scalar fields, etc.).We present a general approach that is completely independent of the simplification technique adopted to reduce the mesh size. We use resampled textures (rgb, bump, displacement or shade maps) to decouple attribute detail representation from geometry simplification. The original contribution is that preservation is performed after simplification by building a set of triangular texture patches that are then packed into a single texture map. This general solution can be applied to the output of any topology-preserving simplification code and it allows any attribute value defined on the high-resolution mesh to be recovered. Moreover, decoupling shape simplification from detail preservation (and encoding the latter with texture maps) leads to high simplification rates and highly efficient rendering.
We also describe an alternative application: the conversion of 3D models with 3D procedural textures (which generally force the use of software renderers) into standard 3D models with 2D bitmap textures
Real Time, Accurate, Multi-Featured Rendering of Bump Mapped Surfaces
We present a new technique to render in real time objects which have part of their high frequency geometric detail encoded in bump maps. It is based on the quantization of normal-maps, and achieves excellent result both in rendering time and rendering quality, with respect to other alternative methods. The method proposed also allows to add many interesting visual effects, even for object with large bumb maps, including non-photorealistic rendering, chrome effects, shading under multiple lights, rendering of different materials within a single object, specular reflections and others. Moreover, the implementation of the method is not complex and can be eased by software reuse
Marching Intersections: An Efficient Approach to Shape-from-Silhouette
A new shape-from-silhouette algorithm for the creation of 3D digital models is presented. The algorithm is based on the use of the Marching Intersection (MI) data structure, a volumetric scheme which allows ef\ufb01cient representation of 3D polyhedra and reduces the boolean operations between them to simple boolean operations on linear intervals. MI supports the de\ufb01nition of a direct shape-from-silhouette approach: the 3D conoids built from the silhouettes extracted from the images of the object are directly intersected to form the resulting 3D digital model. Compared to existing methods, our approach allows high quality models to be obtained in an ef\ufb01cient way. Examples on synthetic objects together with quantitative and qualitative evaluations are given
Volumetric real-time particle-based representation of large unstructured tetrahedral polygon meshes
In this paper we propose a particle-based volume rendering approach for unstructured, three-dimensional, tetrahedral polygon meshes. We stochastically generate millions of particles per second and project them on the screen in real-time. In contrast to previous rendering techniques of tetrahedral volume meshes, our method does not need a prior depth sorting of geometry. Instead, the rendered image is generated by choosing particles closest to the camera. Furthermore, we use spatial superimposing. Each pixel is constructed from multiple subpixels. This approach not only increases projection accuracy, but allows also a combination of subpixels into one superpixel that creates the well-known translucency effect of volume rendering. We show that our method is fast enough for the visualization of unstructured three-dimensional grids with hard real-time constraints and that it scales well for a high number of particles
Taking stock of nature: Essential biodiversity variables explained
In 2013, the Group on Earth Observations Biodiversity Observation Network (GEO BON) developed the framework of Essential Biodiversity Variables (EBVs), inspired by the Essential Climate Variables (ECVs). The EBV framework was developed to distill the complexity of biodiversity into a manageable list of priorities and to bring a more coordinated approach to observing biodiversity on a global scale. However, efforts to address the scientific challenges associated with this task have been hindered by diverse interpretations of the definition of an EBV. Here, the authors define an EBV as a critical biological variable that characterizes an aspect of biodiversity, functioning as the interface between raw data and indicators. This relationship is clarified through a multi-faceted stock market analogy, drawing from relevant examples of biodiversity indicators that use EBVs, such as the Living Planet Index and the UK Spring Index. Through this analogy, the authors seek to make the EBV concept accessible to a wider audience, especially to non-specialists and those in the policy sector, and to more clearly define the roles of EBVs and their relationship with biodiversity indicators. From this we expect to support advancement towards globally coordinated measurements of biodiversity
Uncertainty in species diversity mapping: unravelling a long lasting theme
Many geospatial tools have been advocated in spatial ecology and biogeography to estimate biodiversity and its changes over space and time. Such information is essential in designing effective strategies for biodiversity conservation and management.
Remote sensing is one of the most powerful approaches to identify biodiversity hotspots and predict changes in species composition in reduced time and costs. This is because, with respect to field-based methods, it allows to derive complete spatial coverages of the Earth surface under study in a short period of time. Furthermore, remote sensing provides repeated coverages of field sites, thus making studies of temporal changes in biodiversity possible.
Thus far, species diversity estimates from remote sensing have rarely taken into account uncertainty in an explicit manner. On the contrary, the spatial distribution of uncertainty should explicitly be shown on maps to avoid ignoring overall accuracy or model errors.
In this talk I will discuss, from a conceptual point of view, the potential of remote sensing in estimating biodiversity using various diversity indices. I will also face challenges in the representation of uncertainty methods mainly based on Bayesian logistic regression coupled with simulation-based Monte Carlo techniques and Cartograms applied to European and worldwide datasets for explicitly mapping uncertainty in the distribution of species diversity in a Free and Open Source environment
Off-label Utilization of Antihypertensive Medications in Children
Objective— To examine off-label utilization and costs of antihypertensive drugs in children using a national sample of prescription claims. Design— Cross-sectional study. Setting— 2002 Medstat MarketScan Database, a national sample of outpatient prescription claims of children ≥18 years old enrolled in private, employer-sponsored health plans. Main Outcome Measures— Off-label use of antihypertensive drugs by patient age and costs of
antihypertensives calculated as mean cost per child per 30-day fill.
Results— One-half of the index antihypertensive prescription claims were off-label, based on minimum age criteria. Boys were more likely (56%) than girls (46%) to be prescribed off-label antihypertensives (p<0.001). Children aged ≥12 years were more likely to be prescribed off-label antihypertensives (53%) compared with children aged ≥5 (46%) and 6–11 years (42%, p<0.001). Off-label use varied significantly by class of antihypertensive drugs (p<0.001). Overall, off-label antihypertensives were significantly more expensive than on-label antihypertensives. Conclusions— Despite availability of often less expensive on-label alternatives for the same class of antihypertensive drugs, off-label antihypertensive drugs were prescribed frequently in children. These findings underscore the potential clinical and economic implications of common off-label prescribing, for children, their parents, physicians and payers. Originally published Ambulatory Pediatrics, Vol. 7, No. 4, July 200
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Preconditioning 2D integer data for fast convex hull computations
In order to accelerate computing the convex hull on a set of n points, a heuristic procedure is often applied to reduce the number of points to a set of s points, s ? n, which also contains the same hull. We present an algorithm to precondition 2D data with integer coordinates bounded by a box of size p × q before building a 2D convex hull, with three distinct advantages. First, we prove that under the condition min(p, q) ? n the algorithm executes in time within O(n); second, no explicit sorting of data is required; and third, the reduced set of s points forms a simple polygonal chain and thus can be directly pipelined into an O(n) time convex hull algorithm. This paper empirically evaluates and quantifies the speed up gained by preconditioning a set of points by a method based on the proposed algorithm before using common convex hull algorithms to build the final hull. A speedup factor of at least four is consistently found from experiments on various datasets when the condition min(p, q) ? n holds; the smaller the ratio min(p, q)/n is in the dataset, the greater the speedup factor achieved
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