3,135 research outputs found

    Self-Dual codes from (−1,1)-matrices of skew symmetric type

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    Previously, self-dual codes have been constructed from weighing matrices, and in particular from conference matrices (skew and symmetric). In this paper, codes constructed from matrices of skew symmetric type whose determinants reach the Ehlich- Wojtas’ bound are presented. A necessary and sufficient condition for these codes to be self-dual is given, and examples are provided for lengths up to 52.Ministerio de Ciencia e Innovación MTM2008-06578Junta de Andalucía FQM-016Junta de Andalucía P07-FQM-0298

    Development of an Analytic Nodal Diffusion Solver in Multigroups for 3D Reactor Cores with Rectangular or Hexagonal Assemblies.

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    More accurate modelling of physical phenomena involved in present and future nuclear reactors requires a multi-scale and multi-physics approach. This challenge can be accomplished by the coupling of best-estimate core-physics, thermal-hydraulics and multi-physics solvers. In order to make viable that coupling, the current trends in reactor simulations are along the development of a new generation of tools based on user-friendly, modular, easily linkable, faster and more accurate codes to be integrated in common platforms. These premises are in the origin of the NURESIM Integrated Project within the 6th European Framework Program, which is envisaged to provide the initial step towards a Common European Standard Software Platform for nuclear reactors simulations. In the frame of this project and to reach the above-mentioned goals, a 3-D multigroup nodal solver for neutron diffusion calculations called ANDES (Analytic Nodal Diffusion Equation Solver) has been developed and tested in-depth in this Thesis. ANDES solves the steady-state and time-dependent neutron diffusion equation in threedimensions and any number of energy groups, utilizing the Analytic Coarse-Mesh Finite-Difference (ACMFD) scheme to yield the nodal coupling equations. It can be applied to both Cartesian and triangular-Z geometries, so that simulations of LWR as well as VVER, HTR and fast reactors can be performed. The solver has been implemented in a fully encapsulated way, enabling it as a module to be readily integrated in other codes and platforms. In fact, it can be used either as a stand-alone nodal code or as a solver to accelerate the convergence of whole core pin-by-pin code systems. Verification of performance has shown that ANDES is a code with high order definition for whole core realistic nodal simulations. In this paper, the methodology developed and involved in ANDES is presented

    An automatic maintenance system for nuclear power plants instrumentation

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    Maintenance and testing of reactor protection systems is an important cause of unplanned reactor trips due to be commonly carried out in manual mode. The execution of surveillance procedures in this mode entails a great number of manual operations. Automated testing is the answer because it minimises test times and reduces the risk of human errors. GAMA-I is an automatic system for testing the reactor protection instrumentation which is based on VXI instrumentation cards. This system has important advantages over previous ones in terms of easiness to carry out software modifications related to configuration changes in the protection system. The system uses visual programming and the modifications can be implemented by ordinary instrumentation specialists without programming experience.The system has been developed at the Vandellos II Nuclear Power Plant by the I&C groups of Vandellos II, Tecnatom S.A. and ENWESA Servicios S.A. The representation for this project is held by the Spanish Association for the Nuclear Technologic Development (DTN). Financial support for this research was provided by the Electrical and Electronic Research Program (PIE-OCIDE) of the Spanish Ministry of Industry

    Prolinamides as Asymmetric Organocatalysts

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    Producción CientíficaProlinamides are valuable organocatalysts for enantioselective transformations that occur by activation of the nucleophile by enamine formation. Different substituents can be appended on the nitrogen atom of the carboxamide, which allow for the modulation of the catalytic properties. In that way, the acidity, the hydrogen donor properties, the hydrophobicity, or the chiral environment can be modified, in a few steps, starting from easily available proline.Ministerio de Economía, Industria y Competitividad (CTQ2014-59870-P)Junta de Castilla y León (programa de apoyo a proyectos de investigación – Ref. VA064U13

    Error correcting codes from quasi-Hadamard matrices

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    Levenshtein described in [5] a method for constructing error correcting codes which meet the Plotkin bounds, provided suitable Ha- damard matrices exist. Uncertainty about the existence of Hadamard matrices on all orders multiple of 4 is a source of difficulties for the prac- tical application of this method. Here we extend the method to the case of quasi-Hadamard matrices. Since efficient algorithms for constructing quasi-Hadamard matrices are potentially available from the literature (e.g. [7]), good error correcting codes may be constructed in practise. We illustrate the method with some examples.Junta de Andalucía FQM–29

    Unraveling the Molecular Determinants of Manual Therapy: An Approach to Integrative Therapeutics for the Treatment of Fibromyalgia and Chronic Fatigue Syndrome/Myalgic Encephalomyelitis

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    Application of protocols without parameter standardization and appropriate controls has led manual therapy (MT) and other physiotherapy-based approaches to controversial outcomes. Thus, there is an urgency to carefully define standard protocols that elevate physiotherapy treatments to rigorous scientific demands. One way in which this can be achieved is by studying gene expression and physiological changes that associate to particular, parameter-controlled, treatments in animal models, and translating this knowledge to properly designed, objective, quantitatively-monitored clinical trials (CTs). Here, we propose a molecular physiotherapy approach (MPTA) requiring multidisciplinary teams, to uncover the scientific reasons behind the numerous reports that historically attribute health benefits to MT-treatments. The review focuses on the identification of MT-induced physiological and molecular responses that could be used for the treatment of fibromyalgia (FM) and chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME). The systemic effects associated to mechanical-load responses are considered of particular relevance, as they suggest that defined, low-pain anatomic areas can be selected for MT treatment and yet yield overall benefits, an aspect that might result in it being essential to treat FM. Additionally, MT can provide muscle conditioning to sedentary patients without demanding strenuous physical effort, which is particularly detrimental for CFS/ME patients, placing MT as a real option for integrative medicine programs to improve FM and CFS/ME.This research was funded by the Fundación Universidad Católica de Valencia San Vicente Mártir (UCV) Research Grant Program grant number 2018-121-001.Fisioterapi

    Modelo computacional para la formación de clases de equivalencia

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    A computational model of neuronal net closely related with the formation of equivalence classes is developed. First the formal pattern of the neuronal net is presented and then its operation and its direct relationship with the phenomenon of the formation of the equivalence classes and with the derived relationships are explained. Later on, the validation of the pattern is described carrying out several simulations allowing verification of the pattern so it is able to generate relationships not explicitly trained, these results being adjusted to the basic results of this investigation line. These simulations were carried out using a training of classic conditioning and a test phase by means of conditional discriminations

    Determinants of (–1,1)-matrices of the skew-symmetric type: a cocyclic approach

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    An n by n skew-symmetric type (−1, 1)-matrix K = [ki,j ] has 1’s on the main diagonal and ±1’s elsewhere with ki,j = −kj,i. The largest possible determinant of such a matrix K is an interesting problem. The literature is extensive for n 0 mod 4 (skew- Hadamard matrices), but for n 2 mod 4 there are few results known for this question. In this paper we approach this problem constructing cocyclic matrices over the dihedral group of 2t elements, for t odd, which are equivalent to (−1, 1)-matrices of skew type. Some explicit calculations have been done up to t = 11. To our knowledge, the upper bounds on the maximal determinant in orders 18 and 22 have been improved.Junta de Andalucía FQM-01

    Embedding cocylic D-optimal designs in cocylic Hadamard matrices

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    A method for embedding cocyclic submatrices with “large” determinants of orders 2t in certain cocyclic Hadamard matrices of orders 4t is described (t an odd integer). If these determinants attain the largest possible value, we are embedding D-optimal designs. Applications to the pivot values that appear when Gaussian elimination with complete pivoting is performed on these cocyclic Hadamard matrices are studied.Ministerio de Ciencia e Innovación MTM2008-06578Junta de Andalucía FQM-016Junta de Andalucía P07-FQM-0298

    Economía Social y cooperativas de trabajo asociado como alternativa de futuro tras la crisis provocada por la COVID-19

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    Estamos viviendo una época marcada por la pandemia de la comúnmente denominada COVID-19. Esta enfermedad ha avanzado alrededor de todo el planeta consiguiendo hacer tambalear, incluso, a las economías más consolidadas del mundo. En este contexto, el fomento, desarrollo y puesta en marcha de políticas propias de la economía social cobran todavía un mayor sentido, pues parece inevitable que una vez consigamos volver a la “normalidad" sean muchos los retos que debamos afrontar a nivel mundial, y la experiencia nos ha demostrado que cuando el crecimiento económico ha ido de la mano de la economía social esto se ha traducido en términos de progresos social y democracia. Aportaremos posibles medidas a esta venidera situación en el marco de la economía social, sin embargo, antes de ello serán muchas las paradas ineludibles que habremos de tomar para poder alcanzar esa meta. Nos remontaremos a los orígenes de esta disciplina, al cómo, el cuándo y el porqué de su surgimiento, y en aras de una mejor contextualización, profundizaremos en el análisis y estudio del marco jurídico y la legislación vigente en esta materia, concreta y especialmente, nos centraremos en el análisis de la Ley 5/2011, de 29 de marzo, de Economía Social. Por último, el trabajo contará con una especial referencia a las cooperativas de trabajo asociado y a su marco jurídico en España por el interés que suscitan para el cometido que nos atañe.<br /
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