5,685 research outputs found

    Impact of origin-destination information in epidemic spreading

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    The networked structure of contacts shapes the spreading of epidemic processes. Recent advances on network theory have improved our understanding of the epidemic processes at large scale. The relevance of several considerations still needs to be evaluated in the study of epidemic spreading. One of them is that of accounting for the influence of origin and destination patterns in the flow of the carriers of an epidemic. Here we compute origin-destination patterns compatible with empirical data of coarse grained flows in the air transportation network. We study the incidence of epidemic processes in a metapopulation approach considering different alternatives to the flows prior knowledge. The data-driven scenario where the estimation of origin and destination flows is considered turns out to be relevant to assess the impact of the epidemics at a microscopic level (in our scenario, which populations are infected). However, this information is irrelevant to assess its macroscopic incidence (fraction of infected populations). These results are of interest to implement even better computational platforms to forecast epidemic incidence

    Motif-based communities in complex networks

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    Community definitions usually focus on edges, inside and between the communities. However, the high density of edges within a community determines correlations between nodes going beyond nearest-neighbours, and which are indicated by the presence of motifs. We show how motifs can be used to define general classes of nodes, including communities, by extending the mathematical expression of Newman-Girvan modularity. We construct then a general framework and apply it to some synthetic and real networks

    Low-lying spectra in anharmonic three-body oscillators with a strong short-range repulsion

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    Three-body Schroedinger equation is studied in one dimension. Its two-body interactions are assumed composed of the long-range attraction (dominated by the L-th-power potential) in superposition with a short-range repulsion (dominated by the (-K)-th-power core) plus further subdominant power-law components if necessary. This unsolvable and non-separable generalization of Calogero model (which is a separable and solvable exception at L = K = 2) is presented in polar Jacobi coordinates. We derive a set of trigonometric identities for the potentials which generalizes the well known K=2 identity of Calogero to all integers. This enables us to write down the related partial differential Schroedinger equation in an amazingly compact form. As a consequence, we are able to show that all these models become separable and solvable in the limit of strong repulsion.Comment: 18 pages plus 6 pages of appendices with new auxiliary identitie

    Los edificios de paneles más altos de España

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    RESUMEN Este artículo describe el proceso constructivo de un conjunto de 484 viviendas realizadas con paneles prefabricados portantes de hormigón. Dicho conjunto edi¿catorio, de 20 plantas de altura, se compone de diversos bloques que integran además, locales comerciales, o¿cinas, trasteros, 4 plantas de garaje e instalaciones comunes. El principal interés de este edi¿cio consiste en haber alcanzado veinte plantas sobre rasante y 4 más de sótano con el sistema constructivo de paneles prefabricados de hormigón INDAGSA; el cual dispone de un Documento de Idoneidad Técnica emitido por el IETcc, con el número DIT 452. Las obras de INDAGSA son conocidas por ser precisas, ordenadas y limpias; debido a estas características, se pudieron establecer visitas no sólo para doctorandos de la ETSAM, sino para estudiantes de la Cátedra de sistemas industrializados y prefabricados. A través de la descripción del sistema constructivo, podremos mostrar una perspectiva global de las posibilidades de los sistemas de paneles prefabricados de hormigón y las capacidades evolutivas de éstos

    Roper Excitation in Alpha-Proton Scattering

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    We study the Roper excitation in the (α,α)(\alpha,\alpha') reaction. We consider all processes which may be relevant in the Roper excitation region, namely, Roper excitation in the target, Roper excitation in the projectile, and double Δ\Delta excitation processes. The theoretical investigation shows that the Roper excitation in the proton target mediated by an isoscalar exchange is the dominant mechanism in the process. We determine an effective isoscalar interaction by means of which the experimental cross section is well reproduced. This should be useful to make predictions in related reactions and is a first step to construct eventually a microscopic NNNNNN \rightarrow NN^* transition potential, for which the present reaction does not offer enough information.Comment: Latex 17 pages; figures available by request; Phys. Rev. C in prin

    Optimizing tip-surface interactions in ESR-STM experiments

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    Electron-spin resonance carried out with scanning tunneling microscopes (ESR-STM) is a recently developed experimental technique that is attracting enormous interest on account of its potential to carry out single-spin on-surface resonance with subatomic resolution. Here we carry out a theoretical study of the role of tip-adatom interactions and provide guidelines for choosing the experimental parameters in order to optimize spin resonance measurements. We consider the case of the Fe adatom on a MgO surface and its interaction with the spin-polarized STM tip. We address three problems: first, how to optimize the tip-sample distance to cancel the effective magnetic field created by the tip on the surface spin, in order to carry out proper magnetic field sensing. Second, how to reduce the voltage dependence of the surface-spin resonant frequency, in order to minimize tip-induced decoherence due to voltage noise. Third, we propose an experimental protocol to infer the detuning angle between the applied field and the tip magnetization, which plays a crucial role in the modeling of the experimental results.Comment: 10 pages, 5 Figure

    Nuevos escenarios para la adquisición de conocimientos medioambientales. Una experiencia en la Facultad de Educación y Humanidades de Melilla

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    Desde el año 2006 se viene desarrollando en la Facultad de Educación y Humanidades de Melilla (UGR) el proyecto “Propuesta metodológica para el aprendizaje autónomo de conceptos medioambientales en la formación de maestros”, que nace con la intención de adecuar la metodología de la asignatura obligatoria Fundamentos científicos medioambientales, al sistema de enseñanza impulsado por el Espacio Europeo de Educación Superior a la vez que trata de dar respuesta a la escasez de recursos didácticos que relacionan el conocimiento del entorno local, en sus facetas ambiental y urbana, con los conocimientos que se deben trabajar en la formación inicial de los futuros maestros. En el presente trabajo se aportan algunos de los resultados obtenidos tras la puesta en práctica de una metodología activa en donde se combinan distintos escenarios de enseñanza-aprendizaje

    Preanalytical errors: the professionals’ perspective

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    This study was aimed at understanding the perspective on preanalytical errors from the point of view of the professionals involved in the preanalytical process. A significant contribution of their specialized knowledge and experience in day-to-day practice for identifying these kinds of mistakes, and their most frequent causes, was expected.It seems evident that weaknesses and threats are closely related to institutional organization aspects and the same is true for positive elements (strengths and opportunities). There is also an important appreciation of the staff’s implication. Staff´s opinions should be taken into account by institution managers, as they offer an approach that is different and complementary to the one traditionally applied, which is purely managerial and therefore not sufficient. The results should be complemented with more updated information. Multidisciplinary cooperation must involve not only professionals from different fields but also with different roles, i.e., managers, in order to obtain results that can be used to improve healthcare, save costs and to guarantee patient’s safety. We will continue with this research line investigating the same questions among primary care staff, in order to assess “the other side of the coin” of this problem.This study was partially supported by project Fondo de Investigaciones Sanitarias (FIS) grant PIFIS 1099/12 from “Instituto de Salud Carlos III” Ministerio de Sanidad y Política Social. Gobierno de España. (Health Ministry, Spanish Government).Yes2015-04-0
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