1,533 research outputs found
Model-driven design of geo-information services
This thesis presents a method for the development of distributed geo-information systems. The method is organised around the design principles of modularity, reuse and replaceability. The method enables the modelling of both behavioural and informational aspects of geo-information systems in an integrated way. This thesis introduces the concept the Geo-information Service Infrastructure (GSI)
Flexible and practical modeling of animal telemetry data: hidden Markov models and extensions
We discuss hidden Markov-type models for fitting a variety of multistate random walks to wildlife movement data. Discrete-time hidden Markov models (HMMs) achieve considerable computational gains by focusing on observations that are regularly spaced in time, and for which the measurement error is negligible. These conditions are often met, in particular for data related to terrestrial animals, so that a likelihood-based HMM approach is feasible. We describe a number of extensions of HMMs for animal movement modeling, including more flexible state transition models and individual random effects (fitted in a non-Bayesian framework). In particular we consider so-called hidden semi-Markov models, which may substantially improve the goodness of fit and provide important insights into the behavioral state switching dynamics. To showcase the expediency of these methods, we consider an application of a hierarchical hidden semi-Markov model to multiple bison movement paths
Mitochondrial dysfunction promoted by Porphyromonas gingivalis lipopolysaccharide as a possible link between cardiovascular disease and periodontitis
Oxidative stress is one of the factors that could explain the pathophysiological mechanism of inflammatory conditions that occur in cardiovascular disease (CVD) and periodontitis. Such inflammatory response is often evoked by specific bacteria, as the lipopolysaccharide (LPS) of Porphyromonas gingivalis is a key factor in this process. The aim of this research was to study the role of mitochondrial dysfunction in peripheral blood mononuclear cells (PBMCs) from periodontitis patients and to evaluate the influence of LPS on fibroblasts to better understand the pathophysiology of periodontitis and its relationship with CVD. PBMCs from patients showed lower CoQ10 levels and citrate synthase activity, together with high levels of ROS production. LPS-treated fibroblasts provoked increased oxidative stress and mitochondrial dysfunction by a decrease in mitochondrial protein expression, mitochondrial mass, and mitochondrial membrane potential. Our study supports the
hypothesis that LPS-mediated mitochondrial dysfunction could be at the origin of oxidative stress in periodontal patients. Abnormal PBMC performance may promote oxidative stress and alter cytokine homeostasis. In
conclusion, mitochondrial dysfunction could represent a possible link to understanding the interrelationships between two prominent inflammatory diseases: periodontitis and CV
Bedform variability and flow regime in a barrier-inlet system. The mesotidal Piedras mouth (Huelva, SW Spain)
Bedform fields from the Piedras River mouth (Huelva, SW Spain) have been studied using side-scan sonar techniques, combined with visual scuba-dives, and direct geometric measuring. The dominant flow regime has been determined from the results in these tidal environments, where erosive processes dominate during ebb, transporting sand as a bedload towards the mouth and central sector of the tidal channel. The process is reversed during tidal floods. During neap tides, larger bedforms maintain their geometry and position, whereas small ripples are re-oriented under different tidal conditions. Sand patches, dunes and ripples are interpreted as sediment bypassing zones. Large forms indicate high energy flow, which can only migrate when flow velocity reaches threshold values for the movement, with net sand transport towards open areas. Depositional features indicate low, moderate, and high-energy conditions. Here, a depositional regime dominated by sediment accommodation is dominant, where sandy sediments are continuously remobilized, transported and re-deposited, even closer to the estuarine mouth. In inner zones finer particles, such as clay and silt, are transported by tides as suspended matter and deposited in protected inner areas. The final results are long narrow tidal flats, which alternate with sandy areas dominated by erosion
Status and preliminary results of the ANAIS experiment at Canfranc
ANAIS (Annual Modulation with NaI's) is an experiment planned to investigate
seasonal modulation effects in the signal of galactic WIMPs using up to 107 kg
of NaI(Tl) in the Canfranc Underground Laboratory (Spain). A prototype using
one single crystal (10.7 kg) is being developed before the installation of the
complete experiment; the first results presented here show an average
background level of 1.2 counts/(keV kg day) from threshold (Ethr~4 keV) up to
10 keV.Comment: 3 pages, 2 figures, talk delivered at the 7th International Workshop
on Topics in Astroparticle and Underground Physics (TAUP 2001), September
2001, Laboratori Nazionali del Gran Sasso, Italy (to appear in the Conference
Proceedings, Nucl. Phys. B (Proc. Suppl.)
La reconstrucció de l'església romànica de Sant Esteve de Bas, després dels terratrèmols dels segle XV
Històricament, el del segle XV és el de major importància al nostre país. La que Fontserè i Iglésies anomenen «sèrie olotina» (1) comprèn, almenys, set anys de commocions sísmiques que arriben al paroxisme el 1427 i 1428, amb cotes que a Olot seran de l'ordre dels graus IX i X de l'escala Mercali, amb la destrucció total de la vila. Els moviments segueixen sempre la línia Amer-Hostoles-vescomtat de Bas-Olot. Com assenyalen els autors citats, «cada sacsejada culminant apareix precedida i succeïda per vibracions de menor consideració, que semblen anunciar primer, i, després perllongar el fenomen fins a enllaçar amb la nova fase» (2). Quant a referències documentals concretes a la vall de Bas, a efectes de la precisa datació del sismisme i els seus estralls locals, si bé tenim alguns testimonis de major excepció, pel fet d'ésser coetanis dels esdeveniments, les notícies que ens proporcionen són mínimes i, encara, una mica confuses
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