2,229 research outputs found

    Network coevolution drives segregation and enhances Pareto optimal equilibrium selection in coordination games

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    In this work we assess the role played by the dynamical adaptation of the interactions network, among agents playing Coordination Games, in reaching global coordination and in the equilibrium selection. Specifically, we analyze a coevolution model that couples the changes in agents’ actions with the network dynamics, so that while agents play the game, they are able to sever some of their current connections and connect with others. We focus on two action update rules: Replicator Dynamics (RD) and Unconditional Imitation (UI), and we define a coevolution rule in which, apart from action updates, with a certain rewiring probability p, agents unsatisfied with their current connections are able to eliminate a link and connect with a randomly chosen neighbor. We call this probability to rewire links the ‘network plasticity’. We investigate a Pure Coordination Game (PCG), in which choices are equivalent, and on a General Coordination Game (GCG), for which there is a risk-dominant action and a payoff-dominant one. Changing the plasticity parameter, there is a transition from a regime in which the system fully coordinates on a single connected component to a regime in which the system fragments in two connected components, each one coordinated on a different action (either if both actions are equivalent or not). The nature of this fragmentation transition is different for different update rules. Second, we find that both for RD and UI in a GCG, there is a regime of intermediate values of plasticity, before the fragmentation transition, for which the system is able to fully coordinate on a single component network on the payoff-dominant action, i.e., coevolution enhances payoff-dominant equilibrium selection for both update rules

    Kinematic and dynamic array of the alpine deformations in alto Tajo area (Guadalajara)

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    The geological macrostructure of Alto Tajo is defined by several N1500E dextral strike-slip faults with related secundary structures. The former set of faults together with others N-S sinistral strike-slip faults delimited areas in transtension and transpession. Four tectonic phases have been detected by means of microstructural analysis: N600E compression; N1500E compression (the main deformation phase). N-S compression, without important structures asociated and a last episode of radial extension.Depto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasFALSEpu

    Tensorial analisis of the superposed deformation in the easthern border of the Madrid basin

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    An analysis of Neogene brittle deformation using fault populatíon analysis methods has been carried out between the SW border of the Iberian Range and Altomira Range. Two main paleostress fields have been established: 1) N70E - N120E compression (Altomira paleostress field) ofLate Oligocene - Early Miocene age that induced the formation of the SW border of Iberian Range and Altomira - Pareja thrust belts with reverse and strike-slip faults. 2) N140-N160E compression (Guadarrama paleostress field) of Middle Aragonian - early Pleistocene age that reactivated previous faults with strikeslip movement along the Iberian Range. A superposition of two regional stress fields (Iberian and Guadarrama) is proposed to explain E-W compression that formed Altomira Range. Stress tensorial additions have been realized to check this hypothesis

    Characterization of plasmid-mediated beta-lactamases in fecal colonizing patients in the hospital and community setting in Spain

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    Aim: Active surveillance of plasmid-mediated ß-lactamase-producing Enterobacteriaceae (PMBL-E) in fecal carriers in the hospital and in the community setting in a non-outbreak period of time. Methods: Patients were screened for carriage of Enterobacteriaceae resistant to expanded-spectrum cephalosporins and PMBL-E were characterized (extended-spectrum-ß-lactamase [ESBL], plasmid-mediated AmpC ß-lactamase [pAmpC], and carbapenemases) by PCR and sequencing. Results: The prevalence of ESBL and pAmpC carriers was 5.06% and 0.59%, respectively. Overall, CTX-M-like enzymes were the ESBL dominate enzymes (96.15%). The group CTX-M-9 was the most prevalent (81, 54%) [CTX-M-14 (74, 91.35%), CTX-M-9 (5, 6.17%), CTX-M-24 (1, 1.23%), and CTX-M-27 (1, 1.23%)] followed by the group CTX-M-1 (64, 42.67%) [CTX-M-15 (42, 65.63%), CTX-M-1 (13, 20.31%), CTX-M-32 (8, 12.5%), and CTX-M-3 (1, 1.56%)]. One CTX-M-10, one CTX-M-59, and three CTX-M-8 were also found. A very small representation of SHV or TEM ESBL enzymes was found (3.2% and 0.64%, respectively). pAmpC characterization revealed a predominance of CMY-2 (81.25%), followed by DHA-1 (18.75%). We did not detect the presence of carbapenemase producers. Conclusions: The prevalence of ESBL-producers from fecal carriers is stable in our area, but colonization by pAmpC producers has emerged recently as we have confirmed. Periodic active surveillance is useful to identify these human reservoirs and control the evolution of PMBL carriage in a community over time

    Tribological behavior of oils additised with a phosphonium-derived ionic liquid compared to a commercial oil

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    Purpose: The purpose of this paper is to study the antifriction, antiwear and tribolayer formation properties of the trihexyltetradecylphosphonium bis(2,4,4-trimethylpentyl) phosphinate ionic liquid (IL) as additive at 1 wt.% in two base oils and their mixtures, comparing the results with those of a commercial oil. Design/methodology/approach: The mixture of the base oils used in the formulation of the commercial oil SAE 0W20 plus the IL was tested under rolling/sliding and reciprocating conditions to determine the so-called Stribeck curve, the tribolayer formation and the antifriction and antiwear behaviors. Findings: The use of this IL as additive in these oils does not change their viscosity; improves the antifriction and antiwear properties of the base oils, making equal or outperforming these properties of the SAE 0W20; and the thickness and formation rate of the tribolayer resulting from the IL-surface interaction is highly dependent on the type of base oil and influence on the friction and wear results. Originality/value: The use of this IL allows to replace partial or totally commercial antifriction and antiwear additives. Peer review: The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-05-2020-0179/

    Ejercicio interlaboratorio de bioensayos marinos para la evaluación de la calidad ambiental de sedimentos costeros. IV. Ensayo de toxicidad sobre sedimento con crustáceos anfípodos

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    9 páginas, 2 figuras, 3 tablas.[EN] Interlaboratory variability was studied for the bioassay using crustacean amphipods. Nine series of data were obtained from different laboratories using four different species (Ampelisca brevicornis, Corophium volutator, Corophium multisetosum and Microdeutopus gryllotalpa), all previously used for sediment toxicity assessment in Spain. Results were studied for interlaboratory variability and according to different confounding factors. The coefficients of variation were similar to those previously reported for this bioassay and sample classification was homogeneous among the laboratories that successfully completed the exercise. No significant tendencies related to test species were identified and it seems that the factor most critically affecting test results and the classification of samples is storage time before testing.[ES] Se estudió la precisión interlaboratorio del bioensayo con crustáceos anfípodos. Se recogieron nueve series de datos procedentes de distintos laboratorios europeos y de cuatro especies distintas (Ampelisca brevicornis, Corophium volutator, Corophium multisetosum y Microdeutopus gryllotalpa), todas ellas usadas previamente para la caracterización de la toxicidad de sedimentos en España. Esos resultados se estudiaron para evaluar la variabilidad interlaboratorio de acuerdo a las diferentes especies y los distintos tiempos de almacenamiento de las muestras antes del ensayo. Los resultados mostraron coeficientes de variación similares a los encontrados en estudios previos y permitieron una clasificación homogénea de las muestras entre los laboratorios que completaron el ejercicio con éxito. No se identificaron tendencias significativas debidas al uso de distintas especies y, al parecer, el factor que puede afectar más críticamente la clasificación de las muestras y, por lo tanto, el uso de los resultados para la toma de decisiones, es el tiempo de almacenamiento de los sedimentos previamente al desarrollo del ensayo.This study was carried out under a joint research project between CEDEX and the University of Cádiz. Part of the work was funded by the Spanish Ministry of Science and Technology REN2002_01699/TECNO). The first author was supported by a grant (FPI) from the Spanish Ministry of Education and Science.Peer reviewe

    Generic competences for the IT knowledge workers: a study from the field.

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    Proceedings of: Third World Summit on the Knowledge Society (WSKS 2010), Corfu, Greece, September 22-24, 2010This paper aims to identify generic competency levels relevant to a particular kind of knowledge workers: software engineers. Based on previous works, and in particular in the description of a professional career, authors review of the literature related to the characterization of the labor force in the Software Engineering (SE) domain. Subsequently, using a quantitative analysis based on investigative surveys administered to a number of representative professionals, authors provide with a generic competency ladder adapted to the given career description.Publicad
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