Joint effect of ageing and multilayer structure prevents ordering in the voter model

The voter model rules are simple, with agents copying the state of a random neighbor, but they lead to non-trivial dynamics. Besides opinion processes, the model has also applications for catalysis and species competition. Inspired by the temporal inhomogeneities found in human interactions, one can introduce ageing in the agents: the probability to update decreases with the time elapsed since the last change. This modified dynamics induces an approach to consensus via coarsening in complex networks. Additionally, multilayer networks produce profound changes in the dynamics of models. In this work, we investigate how a multilayer structure affects the dynamics of an ageing voter model. The system is studied as a function of the fraction of nodes sharing states across layers (multiplexity parameter q ). We find that the dynamics of the system suffers a notable change at an intermediate value q*. Above it, the voter model always orders to an absorbing configuration. While, below, a fraction of the realizations falls into dynamical traps associated to a spontaneous symmetry breaking in which the majority opinion in the different layers takes opposite signs and that due to the ageing indefinitely delay the arrival at the absorbing state.Comment: 10 pages, 8 figure

Is the Voter Model a model for voters?

The voter model has been studied extensively as a paradigmatic opinion dynamics' model. However, its ability for modeling real opinion dynamics has not been addressed. We introduce a noisy voter model (accounting for social influence) with agents' recurrent mobility (as a proxy for social context), where the spatial and population diversity are taken as inputs to the model. We show that the dynamics can be described as a noisy diffusive process that contains the proper anysotropic coupling topology given by population and mobility heterogeneity. The model captures statistical features of the US presidential elections as the stationary vote-share fluctuations across counties, and the long-range spatial correlations that decay logarithmically with the distance. Furthermore, it recovers the behavior of these properties when a real-space renormalization is performed by coarse-graining the geographical scale from county level through congressional districts and up to states. Finally, we analyze the role of the mobility range and the randomness in decision making which are consistent with the empirical observations.Comment: 13 pages, 13 figure

A First Order Analytical Solution for Spacecraft Motion about (433)Eros

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76061/1/AIAA-2002-4543-167.pd

Contra los que atacan las imágenes sagradas. Discurso apologético

Polémicos son también sus discursos apologéticos «sobre las imágenes sagradas», en los que el Damasceno defiende la ortodoxia de la veneración de las imágenes en contra del criterio del emperador León III y de quienes entendían que la veneración de la imagen era, en realidad, una adoración idólatra que debía ser erradicada. El estilo sencillo que Juan de Damasco empleó en estos textos facilitó su difusión entre la población cristiana e incitó a la misma a tomar postura ante la nueva polémica promovida por el poder imperial

A European perspective on nosocomial urinary tract infections II. Report on incidence, clinical characteristics and outcome (ESGINI–04 study)

ObjectivesTo estimate the incidence of nosocomially acquired urinary tract infections (NAUTI) in Europe and provide information on the clinical characteristics, underlying conditions, etiology, management and outcome of patients.Materials and methodsWe collected clinical information from NAUTI patients with a microbiology report on the named study day.ResultsA total of 141 hospitals from 25 European countries participated in the study. Written institutional bladder catheter guidelines were in place in 90.3% of EU hospitals and 55% of non-EU hospitals (P <0.05). The total number of new NAUTI episodes on the day of the study was 298, representing an incidence of 3.55 episodes/1000 patient-days and an estimated prevalence of 10.65/1000. The five most commonly isolated micro-organisms were Escherichia coli, Enterococcus sp., Candida sp., Klebsiella sp. and Pseudomonas aeruginosa. Patients from non-EU countries were younger, with more severe underlying diseases with a higher incidence of obstructive uropathy/lithiasis. Overall, 22.8% of patients had no ‘classic’ UTI-predisposing factors. Catheter-associated UTI (CAUTI) was present in 187 patients (62.8%). A closed drainage system was used in only 78.5% of catheterised patients. The indication for bladder catheterisation was not considered adequate in 7.6% of cases and continuation of bladder catheterisation was considered unnecessary in 31.3%. Opening of the closed drainage system was the most frequent major error in catheter management (16.8%). Antimicrobial treatment was not considered adequate in 19.8% of all cases.ConclusionsThe incidence of NAUTI in a large European population is 3.55/1000 patient-days. There is clearly room for improvement in the area of bladder catheterisation, catheter care and medical management of NAUTI. We recommend that European authorities draw up and implement practical and specific guidelines to reduce the incidence of this infection

Productivity and international competitiveness of agriculture in the European Union and the United States

This study looks at international competitiveness of agriculture in the European Union and the United States. The most intuitive concept is that of price competitiveness.We calculate relative prices for 11 member states of the European Union and the United States for the period 1973–2002. We assume that markets are perfectly competitive and in long-run equilibrium, so that the observed price always equals average total cost, as measured by the cost dual to the production function. This assumption is used in our calculation of relative competitiveness and productivity gaps between the European Union and the United States and in our decomposition of relative price movements between changes in relative input prices and changes in relative productivity levelsPublicad

Viscoelastic behavior of a polyester resin concrete reinforced with nonmetallic bars under bending loads

This paper deals with the study of a highly durable polyester polymer concrete reinforced with glass fibre reinforced polymer rebars. The paper describes the properties of this specific concrete, which were tested using different experimental techniques such as porosimetry, scanning electron microscopy and petrography. Likewise, characterisation in a macro-scale was carried out to define the mechanical properties of the material (modulus of elasticity, stress-strain curve, ultimate strength and bond). Based on the latter properties, the paper presents a relatively simple method to estimate the ultimate bearing capacity of beams under bending load. The calculation method has been verified by testing beams and full-scale elements. At the end, and due to the viscoelastic nature of the polymer, several considerations will be made in order identify safety factors dependent on the loads nature: permanent loads (deferred deformations) and live loads.Peer ReviewedPostprint (author’s final draft

High temperature internal friction in a Tie46Ale1Moe0.2Si intermetallic, comparison with creep behaviour

Advanced g-TiAl based intermetallics Mo-bearing have been developed to obtain the fine-grained microstructure required for superplastic deformation to be used during further processing. In the present work we have studied an alloy of Tie46.8Ale1Moe0.2Si (at%) with two different microstructures, as-cast material with a coarse grain size above 300 mm, and the hot extruded material exhibiting a grain size smaller than 20 mm. We have used a mechanical spectrometer especially developed for high temperature internal friction measurements to study the defect mobility processes taking place at high temperature. The internal friction spectra at different frequencies has been studied and analyzed up to 1360 K in order to characterize the relaxation processes appearing in this temperature range. A relaxation peak, with a maximum in between 900 K and 1080 K, depending on the oscillating frequency, has been attributed to Ti-atoms diffusion by the stress-induced reorientation of AleVTieAl elastic dipoles. The high temperature background in both microstructural states, as-cast and extruded, has been analyzed, measuring the apparent activation parameters, in particular the apparent energies of Ecast(IF) ¼ 4.4 ± 0.05 eV and Eext(IF) ¼ 4.75 ± 0.05 eV respectively. These results have been compared to those obtained on the same materials by creep deformation. We may conclude that the activation parameters obtained by internal friction analysis, are consistent with the ones measured by creep. Furthermore, the analysis of the high temperature background allows establish the difference on creep resistance for both microstructural states.Peer reviewe