Phase ordering and symmetries of the Potts model

We have studied the ordering of the q-colours Potts model in two dimensions on a square lattice. On the basis of our observations we propose that if q is large enough the system is not able to break global and local null magnetisation symmetries at zero temperature: when q<4 the system forms domains with a size proportional to the system size while for q>4 it relaxes towards a non-equilibrium phase with energy larger than the ground state energy, in agreement with the previous findings of De Oliveira et al. (M. J. de Oliveira, A. Petri, T. Tome, Europhys. Lett., 65, 20 (2004)).Comment: 6 pages, 3 figures; minor text rewordings and changes in figures styl

A generalized Holling type II model for the interaction between dextral-sinistral snails and Pareas snakes

Producción CientíficaPareatic snakes possess outstanding asymmetry in the mandibular tooth number, which has probably been caused by its evolution to improve the feeding on the predominant dextral snails. Gene mutation can generate chiral inversion on the snail body. A sinistral snail population can thrive in this ecological context. The interactions between dextral/sinistral snails and Pareas snakes are modeled in this paper by using a new generalized functional response of Holling type II. Distinct Pareas species show different bilateral asymmetry degrees. This parameter plays an essential role in our model and determines the evolution of the populations. Stability of the solutions is also analyzed for different regimes in the space of parameters.Ministerio de Economía, Industria y Competitividad (grant MTM2014-57129-C2-1-P)Junta de Castilla y Leon (grant VA057U16

Hierarchical component-wise models for enhanced stress analysis and health monitoring of composites structures

L'abstract è presente nell'allegato / the abstract is in the attachmen

The present and future state of multi-brand platforms in luxury e-commerce: leveraging digital tools to build customer loyalty

Luxury fashion consumption is changing. For decades, the industry favored premium in-person experiences. Recently, however, luxury brands and consumers have taken notice of online channels, and competition is fiercer than ever. The aim of this thesis is to analyze the industry and specify recommendations for the improvement of a business model employed by major e commerce platforms in luxury fashion, the multi-brand model. Literature, a consumer survey and company records comprise the primary sources of information used to analyze the model and support the elaboration of three major recommendations: integration of metaverse technology, improved customer experience and digital loyalty development

Relationship between the main components of the crystalline lens and the anterior chamber depth after cataract formation

Producción CientíficaPurpose To assess the relationship between anterior chamber depth (ACD) and lens thickness (LT), as well as its three main components (anterior and posterior cortex and nucleus thickness), in cataractous and non-cataractous eyes, depending on the axial length (AxL). Methods Anterior and posterior cortex and nucleus thickness of the crystalline lens, ACD, and AxL were measured using optical low-coherence reflectometry in cataractous and non-cataractous eyes. They were also classified into hyperopia, emme- tropia, myopia, and high myopia, depending on AxL; thus, eight subgroups were created. A minimum sample size of 44 eyes (of 44 patients) for each group was recruited. Linear models were fitted for the whole sample and each AxL subgroup to assess if there were differences in the relationships between the crystalline lens variables and ACD, including age as a covariate. Results Three hundred seventy cataract patients (237 females, 133 males) and 250 non-cataract controls (180 females, 70 males), aged 70.5 ± 9.4 and 41.9 ± 15.5 years, respectively, were recruited. The mean AxL, ACD, and LT for the cataractous and non-cataractous eyes were 23.90 ± 2.05, 24.11 ± 2.11, 2.64 ± 0.45, and 2.91 ± 0.49, 4.51 ± 0.38, 3.93 ± 0.44 mm, respec- tively. The inverse relationship of LT, anterior and posterior cortex, and nucleus thickness with ACD was not significantly (p ≥ 0.26) different between cataractous and non-cataractous eyes. Further subclassification of the sample depending on AxL showed that the inverse relationship between the posterior cortex and ACD was no longer significant (p > 0.05) for any non-cataractous AxL group. LT, anterior and posterior cortex, and nucleus thickness was not significantly (p ≥ 0.43) different between cataractous and non-cataractous eyes for the whole sample, and all AxL groups after adjusting for age. Conclusions The presence of cataracts does not modify the inverse relationship of the LT, anterior and posterior cortex, and nucleus with ACD. And this relationship does not seem to depend importantly on AxL. Besides, the possible differences in LT, anterior and posterior cortex, and nucleus between cataractous and non-cataractous eyes may not be caused by lens opacification, but possibly by the progressive lens growth due to aging.Ministerio de Economía y Competitividad (Instituto de Salud Carlos III) through Research Projects (RETICS RD16/008/0001)Publicación en abierto financiada por el Consorcio de Bibliotecas Universitarias de Castilla y León (BUCLE), con cargo al Programa Operativo 2014ES16RFOP009 FEDER 2014-2020 DE CASTILLA Y LEÓN, Actuación:20007-CL - Apoyo Consorcio BUCL

Geometry of curves and surfaces in contemporary chair design

In the present work, we focus on some of the current trends used in furniture design, from a dual point of view: differential geometry of curves and surfaces, and the existing perspective deriving from the usual techniques of computer-aided design. The contributions of architects such as Alvar Aalto, Mies van der Rohe, Marcel Breuer, Arne Jacobsen and Charles and Ray Eames to contemporary chair design are related to these techniques. Among them, we point out those which are performed by means of spatial geometric transformations of curves and surfaces, with an emphasis on ruled surfaces

Decomposition of sectoral water consumption: a subsystem SAM model for Extremadura, Spain

Though most direct water use is generally associated with agriculture, and therefore with the production of food, there is a clear consensus that considering indirect water uses is a relevant factor to be considered in any environmental analysis. In this regard, the subsystems input-output approach makes it possible to isolate the water relations of a limited number of activities as part of the entire production sphere and thus obtain specific production information of them. However, not directly related with production, the demand of goods and services closely linked to available income, also play a significant role in water consumption. Hence, in this paper we propose an extension of the input?output subsystem model to account for all transactions within a Social Accounting Matrix (SAM) and capture the entire flow by which water depletion is caused and transmitted throughout the economic system. Our approach, which divides the water consumption into different components, illustrates how the individual patterns of water depletion differ among economic agents. The starting point of the subsystems representation consists of the decomposition of the N accounts of a SAM system into two categories of institutions: m endogenous and s exogenous. By taking into account this separation of the accounts, in this paper, we analyze separately all the endogenous economic agents, and for each one, we apply a subsystem division of its water consumption. The empirical application is for the Spanish regional economy of Extremadura, and the economic and environmental data are for the year 2005. Our results show that large asymmetries exist not only in the quantitative contribution of the different economic agents to water consumption, but also in the decomposed effects of this contribution. In particular, this decomposition allows illustration of the pull effects of the SAM economic agents on the others, and this shows the effective consumption caused by one agent, no matter which is the agent that causes the end water consumption. Models such as the one presented here also have limitations, like the shortage of data or parameter specification. However, they are of great interest to define the direction that environmental or economic policies should take if we are to reduce water consumption or increase water use efficiency levels

Trajectory Reconstruction Techniques for Evaluation of ATC Systems

This paper is focused on trajectory reconstruction techniques for evaluating ATC systems, using real data of recorded opportunity traffic. We analyze different alternatives for this problem, from traditional interpolation approaches based on curve fitting to our proposed schemes based on modeling regular motion patterns with optimal smoothers. The extraction of trajectory features such as motion type (or mode of flight), maneuvers profile, geometric parameters, etc., allows a more accurate computation of the curve and the detailed evaluation of the data processors used in the ATC centre. Different alternatives will be compared with some performance results obtained with simulated and real data sets