687 research outputs found

    Mining structured Petri nets for the visualization of process behavior

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    Visualization is essential for understanding the models obtained by process mining. Clear and efficient visual representations make the embedded information more accessible and analyzable. This work presents a novel approach for generating process models with structural properties that induce visually friendly layouts. Rather than generating a single model that captures all behaviors, a set of Petri net models is delivered, each one covering a subset of traces of the log. The models are mined by extracting slices of labelled transition systems with specific properties from the complete state space produced by the process logs. In most cases, few Petri nets are sufficient to cover a significant part of the behavior produced by the log.Peer ReviewedPostprint (author's final draft

    Visualising the South Yorkshire floods of ‘07

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    This paper describes initial work on developing an information system to gather, process and visualise various multimedia data sources related to the South Yorkshire (UK) floods of 2007. The work is part of the Memoir project which aims to investigate how technology can help people create and manage long-term personal memories. We are using maps to aggregate multimedia data and to stimulate remembering past events. The paper describes an initial prototype; challenges faced so far and planned future work

    Evidencias sobre la eficacia de los corredores ecológicos: ¿Solucionan la problemática de fragmentación de hábitats?

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    Se realiza una revisión del estado de la cuestión con respecto al bagaje científico existente sobre la eficacia de los corredores ecológicos como elementos dirigidos a la conservación de especies en paisajes fragmentados. Previamente se enumeran los efectos potenciales positivos y negativos que pudieran tener los corredores sobre la vida silvestre y se describen las principales dificultades metodológicas que presentan los estudios que tienen como objetivo testar dicha eficacia. Se evidencia la existencia de un nivel probatorio creciente sobre los efectos positivos de corredores ecológicos de características adecuadas en materia de conservación, si bien se espera que aumente significativamente el bagaje científico al respecto en los próximos años. El principio de precaución en materia de conectividad ecológica se torna fundamental dentro de la planificación territorial y sectorial, con el objeto de prevenir la pérdida de funcionalidad de los corredores ecológicos remanentes en el territorio.A review of scientific knowledge about the effectiveness of ecological corridors as elements aimed at the conservation of species in fragmented landscapes is conducted. Before, the potential positive and negative effects that corridors might have on wildlife are listed and the main methodological difficulties that show the studies that aim to test that effectiveness are described. It is clear that there is a growing level of evidence about the positive effects of ecological corridors of appropriate characteristics in terms of conservation, although it is expected that the scientific knowledge in this regard increase significantly in the coming years. The precautionary principle in the field of ecological connectivity becomes crucial in landscape planning, in order to prevent the loss of function of ecological corridors remaining in the territory.On réalise une révision de l’état de la question à l’égard du bagage scientifique existant sur l’efficacité des corridors écologiques, comme des éléments dirigés à la conservation d’espèces dans des paisajes fragmentés. Au préalable on énumère les effets potentiels positifs et négatives que peuvent avoir les corridors sur la vie sauvage et on décrit les difficultés principales méthodologiques que présentent les études qui ont pour but tèster la dite efficacité. Bien que les effets positifs des corridors écologiques adecuats sont évidents, on s’attend que le bagage scientifique à ce sujet augmente significativement dans les prochaines années. Le principe de précaution en matière de connectivité écologique deviene fondamental dans la planification territoriale et séctorielle, afin de prévenir la perte de fonctionnalité des corridors écologiques rémanents dans le territoire

    A systematic review of Twitter’s hashtags in public health: an example of a globally adopted standard

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    The objective is to find evidence and make recommendations on the use of Twitter in public health,particularly through the study of hashtags(#). This systematic review shows the use of Twitter in different areas of public health: epidemiological surveillance, health promotion, health protection and disease prevention. Articles on this subject published in indexed journals with impact factor show the importance of conversations to engage the attention of Twitter users by using citations (@ user) and retweets(RT); however, not much importance seems to be given to the use of hashtags(#), which are often assimilated to the concept of keywords. Although tracking recurring hashtagsshould be less expensive than computing Twitter content, the potential of hashtaggeddata has not been properly exploited or recognized over the past years, probably due to the lack of efficient tools

    Schroedinger vs. Navier-Stokes

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    [EN] Quantum mechanics has been argued to be a coarse-graining of some underlying deterministic theory. Here we support this view by establishing a map between certain solutions of the Schroedinger equation, and the corresponding solutions of the irrotational Navier-Stokes equation for viscous fluid flow. As a physical model for the fluid itself we propose the quantum probability fluid. It turns out that the (state-dependent) viscosity of this fluid is proportional to Planck's constant, while the volume density of entropy is proportional to Boltzmann's constant. Stationary states have zero viscosity and a vanishing time rate of entropy density. On the other hand, the nonzero viscosity of nonstationary states provides an information-loss mechanism whereby a deterministic theory (a classical fluid governed by the Navier-Stokes equation) gives rise to an emergent theory (a quantum particle governed by the Schroedinger equation).Fernández De Córdoba, P.; Isidro San Juan, JM.; Vazquez Molina, J. (2016). Schroedinger vs. Navier-Stokes. Entropy. 18(1):1-11. doi:10.3390/e18010034S11118

    Biomimetic Ca-P coatings Incorporating bisphosphonates produced on starch-based degradable biomaterials

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    In this study, sodium clodronate, a well-known therapeutic agent from the family of bisphosphonates (BPs), is incorporated in a biomimetic calcium phosphate (CaP) coating, previously formed on the surface of a starch-based biomaterial by a sodium silicate methodology, as a strategy to develop a site-specific drug delivery system for bone tissue regeneration applications. The effects on the resulting CaP coatings were evaluated in terms of morphology, chemistry, and structure. The dissolution of Ca and P from the coating and the release profiles of sodium clodronate was also assessed. As a preliminary approach, this first study also aimed at evaluating the effects of this BP on the viability of a human osteoblastic cell line since there is still little information available on the interaction between BPs and this type of cells. Sodium clodronate was successfully incorporated, at different doses, in the structure of a biomimetic CaP layer previously formed by a sodium silicate process. This type of BPs had a stimulatory effect on osteoblastic activity, particularly at the specific concentration of 0.32 mg/mL. It is foreseen that these coatings can, for instances, be produced on the surface of degradable polymers and then used for regulating the equilibrium on osteoblastic/osteoclastic activity, leading to a controlled regenerative effect at the interface between the biomaterial and bone

    A comparative study of two different approaches for the incorporation of silver nanoparticles into layer-by-layer films

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    UPNa. Departamento de Ingeniería Eléctrica y Electrónica. Laboratorio de Dispositivos Ópticos NanoestructuradosIn this work, a comparative study about the incorporation of silver nanoparticles (AgNPs) into thin films is presented using two alternative methods, the in situ synthesis process and the layer-by-layer embedding deposition technique. The influence of several parameters such as color of the films, thickness evolution, thermal post-treatment, or distribution of the AgNPs along the coatings has been studied. Thermal post-treatment was used to induce the formation of hydrogel-like AgNPs-loaded thin films. Cross-sectional transmission electron microscopy micrographs, atomic force microscopy images, and UV-vis spectra reveal significant differences in the size and distribution of the AgNPs into the films as well as the maximal absorbance and wavelength position of the localized surface plasmon resonance absorption bands before and after thermal post-treatment. This work contributes forThis work was supported by the Spanish Ministry of Economy and Competitiveness through TEC2010-17805 Research Project, Innocampus Program and Public University of Navarra (UPNA) research grants

    Self-referenced optical fiber sensor for hydrogen peroxide detection based on LSPR of metallic nanoparticles in layer-by-layer films

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    Intensity-based optical fiber sensors are one of the most studied sensor approaches thanks to their simplicity and low cost. Nevertheless, their main issue is their lack of robustness since any light source fluctuation, or unexpected optical setup variation is directly transferred to the output signal, which, significantly reduces their reliability. In this work, a simple and robust hydrogen peroxide (H2O2) optical fiber sensor is proposed based on the Localized Surface Plasmon Resonance (LSPR) sensitivity of silver and gold metallic nanoparticles. The precise and robust detection of H2O2 concentrations in the ppm range is very interesting for the scientific community, as it is a pathological precursor in a wide variety of damage mechanisms where its presence can be used to diagnose important diseases such as Parkinson's disease, diabetes, asthma, or even Alzheimer's disease). In this work, the sensing principle is based the oxidation of the silver nanoparticles due the action of the hydrogen peroxide, and consequently the reduction of the efficiency of the plasmonic coupling. At the same time, gold nanoparticles show a high chemical stability, and therefore provide a stable LSPR absorption band. This provides a stable real-time reference that can be extracted from the spectral response of the optical fiber sensor, giving a reliable reading of the hydrogen peroxide concentration.This work has been supported by the Spanish Economy and Competitiveness TEC2016-78047-R grant and the PhD research grants of the Public University of Navarre

    Ecología del Paisaje. Un marco para el estudio integrado de la dinámica territorial y su incidencia en la vida silvestre

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    A review on the conceptual basis and aims of Landscape Ecology, scientific discipline that presents an important geographical component, is realized. It assumes that landscape heterogeneity controls diverse movements and flows of organisms, matter and energy. One of the principal objects of study of the above mentioned discipline is the existing relations between landscape structural patterns and dynamics of wild populations and communities. This is an aspect of great applicability in biodiversity conservation and land-use planning policies. In relation to this subject matter, transdisciplinarity of Landscape Ecology is described.Se realiza una revisión sobre las bases conceptuales y los objetivos de la Ecología del Paisaje, disciplina científica que presenta un importante componente geográfico. Como punto de partida asume que la heterogeneidad espacio-temporal del paisaje, resultante de la interacción dinámica de las sociedades humanas con el medio, controla diversos movimientos y flujos de organismos, materia y energía. Uno de los principales objetos de estudio de dicha disciplina son las relaciones existentes entre los cambios estructurales del paisaje y la dinámica de poblaciones y comunidades silvestres, configurándose como un aspecto de gran aplicabilidad en las políticas de conservación de la biodiversidad y de planificación territorial con base ecológica. En relación a esta temática, se describe el carácter transdisciplinar de la Ecología del Paisaje
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