1,455 research outputs found

    El tejido industrial de Barcelona. Estructura sectorial y condicionantes territoriales

    Get PDF
    Tot partint de la constatació de la importància de la indústria en I'economia de Barcelona, l'autor descriu I'especialització de la ciutat en sectors de tecnologia intermèdia i el predomini d'empreses de grandària petita i mitjana. A continuació es detallen els factors que incideixen en la localització de la industria al conjunt metropolita, per concloure que les empreses amb una major resistència a les pressions d'expulsió fora les àrees urbanes de major densitat són aquelles que pertanyen a sectors amb alt valor afegit i/o elevada intensitat tecnològica, així com les que estan vinculades a activitats auxiliars (manteniment, reparacions, etc.) i les petites indústries que ocupen espais inadequats i, en ocasions, degradats. Finalment, es detallen algunes actuacions (en els camps de la formació, les infraestructures, els serveis, la tecnologia i la promoció) que, a parer de I'autor, contribuirien a impulsar l'activitat industrial a l'àmbit regional i local.Partiendo de la constatación de la importancia de la industria en la economía de Barcelona, el autor describe la especialización de la ciudad en sectores de tecnología intermedia y el predominio de empresas pequeñas y medianas. A continuación se detallan los factores que inciden en la localización de la industria en el conjunto metropolitano, para concluir que las empresas con mayor resistencia a la expulsión fuera de las áreas urbanas de mayor densidad son las que pertenecen a sectores de alto valor añadido y/o elevada intensidad tecnológica, aquellas que están vinculadas a actividades auxiliares (mantenimiento, reparaciones, etc.) y las pequeñas industrias que ocupan espacios inadecuados y, en ocasiones, degradados. Finalmente, se detallan algunas actuaciones (en los campos de la formación, infraestructuras, servicios, tecnología y promoción) que a juicio del autor contribuirían a impulsar la actividad industrial en el ámbito regional y local

    Motion-Based Design of Passive Damping Devices to Mitigate Wind-Induced Vibrations in Stay Cables

    Get PDF
    Wind action can induce large amplitude vibrations in the stay cables of bridges. To reduce the vibration level of these structural elements, different types of passive damping devices are usually installed. In this paper, a motion-based design method is proposed and implemented in order to achieve the optimum design of different passive damping devices for stay cables under wind action. According to this method, the design problem is transformed into an optimization problem. Thus, its main aim is to minimize the different terms of a multi-objective function, considering as design variables the characteristic parameters of each considered passive damping device. The multi-objective function is defined in terms of the scaled characteristic parameters, one single-function for each parameter, and an additional function that checks the compliance of the considered design criterion. Genetic algorithms are considered as a global optimization method. Three passive damping devices have been studied herein: viscous, elastomeric and friction dampers. As a benchmark structure, the Alamillo bridge (Seville, Spain), is considered in order to validate the performance of the proposed method. Finally, the parameters of the damping devices designed according to this proposal are successfully compared with the results provided by a conventional design method

    Signcryption schemes with threshold unsigncryption, and applications

    Get PDF
    The final publication is available at link.springer.comThe goal of a signcryption scheme is to achieve the same functionalities as encryption and signature together, but in a more efficient way than encrypting and signing separately. To increase security and reliability in some applications, the unsigncryption phase can be distributed among a group of users, through a (t, n)-threshold process. In this work we consider this task of threshold unsigncryption, which has received very few attention from the cryptographic literature up to now (maybe surprisingly, due to its potential applications). First we describe in detail the security requirements that a scheme for such a task should satisfy: existential unforgeability and indistinguishability, under insider chosen message/ciphertext attacks, in a multi-user setting. Then we show that generic constructions of signcryption schemes (by combining encryption and signature schemes) do not offer this level of security in the scenario of threshold unsigncryption. For this reason, we propose two new protocols for threshold unsigncryption, which we prove to be secure, one in the random oracle model and one in the standard model. The two proposed schemes enjoy an additional property that can be very useful. Namely, the unsigncryption protocol can be divided in two phases: a first one where the authenticity of the ciphertext is verified, maybe by a single party; and a second one where the ciphertext is decrypted by a subset of t receivers, without using the identity of the sender. As a consequence, the schemes can be used in applications requiring some level of anonymity, such as electronic auctions.Peer ReviewedPostprint (author's final draft

    Genetic algorithms for the generation of models with micropopulations

    Get PDF
    Proceedings of: EvoWorkshops 2003: EvoBIO, EvoCOP, EvoIASP, EvoMUSART, EvoROB, and EvoSTIM Essex, UK, April 14–16, 2003The present article puts forward a method for an interactive model generation through the use of Genetic Algorithms applied to small populations. Micropopulations actually worsen the problem of the premature convergence of the algorithm, since genetic diversity is very limited. In addition, some key factors, which modify the changing likelihood of alleles, cause the likelihood of premature convergence to decrease. The present technique has been applied to the design of 3D models, starting from generic and standard pieces, using objective searches and searches with no defined objective

    An experimental comparative study for interactive evolutionary computation problems

    Get PDF
    Proceeding of: EvoWorkshops 2006: EvoBIO, EvoCOMNET, EvoHOT, EvoIASP, EvoINTERACTION, EvoMUSART, and EvoSTOC, Budapest, Hungary, April 10-12, 2006This paper presents an objective experimental comparative study between four algorithms: the Genetic Algorithm, the Fitness Prediction Genetic Algorithm, the Population Based Incremental Learning algorithm and the purposed method based on the Chromosome Appearance Probability Matrix. The comparative is done with a non subjective evaluation function. The main objective is to validate the efficiency of several methods in Interactive Evolutionary Computation environments. The most important constraint of working within those environments is the user interaction, which affects the results adding time restrictions for the experimentation stage and subjectivity to the validation. The experiments done in this paper replace user interaction with several approaches avoiding user limitations. So far, the results show the efficiency of the purposed algorithm in terms of quality of solutions and convergence speed, two known keys to decrease the user fatigue.This article has been financed by the Spanish founded research MCyT project OPLINK, Ref: TIN2006-08818-C04-02

    Población extranjera, tipologías delictivas y práctica de la interpretación judicial y policial en la provincia de Málaga: estudio de caso

    Get PDF
    Este artículo versa sobre la práctica de la interpretación judicial y policial en la provincia de Málaga. La importancia de estas prácticas en esta provincia andaluza están íntimamente relacionadas con el volumen de población extranjera que reside, de forma temporal o permanente, en esta zona geográfica del sur de España. De ahí que hayamos procedido a realizar un estudio de población que nos permite poner en relación tres elementos complementarios entre sí: el volumen de población extranjera en Málaga, la importancia que esto tiene para la práctica de la interpretación judicial y policial en esta provincia y las tipologías delictivas más frecuentes, indicando, cuando esto es posible, cuáles son los colectivos extranjeros más implicados y como se denomina, en la jerga de la policía, a estos delitos.G.I. HUM 767 (ayudas a Grupos de Investigación de la Junta de Andalucía) / Editorial Comares (colección interlingua

    A crowd-structure interaction model to analyze the lateral lock-in phenomenon on footbridges

    Get PDF
    In this paper a simplified biomechanical crowd-structure interaction model is proposed and validated in order to analyse the lateral lock-in phenomenon on real footbridges. The proposed crowd-structure interaction model is organized in three levels: (i) pedestrian-structure interaction; (ii) interaction among pedestrians in the crowd; and (iii) interaction between the crowd and the structure. To this end, first, the human-structure interaction of each pedestrian is modelled via a simplified two degrees of freedom system. Second, the interaction among pedestrians inside the crowd is simulated using a multi-agent model. The considered model simulates the movement of each pedestrian from the dynamic equilibrium of the different social forces that act on him/her. Finally, the crowd-structure interaction is achieved modifying the behaviour of the pedestrians depending on the comfort level experienced. For this purpose, the recommendations established by the French standards have been considered. The integration of the three levels in an overall model is achieved by the implementation of a predictive– corrective method. The performance of the proposed model is validated correlating the numerical and experimental dynamic response of the Pedro e Inês footbridge during the development of a lateral lock-in pedestrian test. As the first lateral natural frequency of the footbridge is inside the range that characterizes the walking pedestrian step frequency in lateral direction, numerical and experimental studies were performed to analyse its behaviour under pedestrian action. The agreement between the numerical and experimental results is adequate. However, further studies are recommended in order to generalize the proposed approach and facilitate its use during the design project of future footbridges.Ministerio de Ciencia DPI2014-53947-

    Descrita una nova espècie del Prepirineu català

    Get PDF
    Un grup d'investigadors de la UAB ha descrit una nova espècie de planta, anomenada Centaurea tripontina, a la zona del congost de Tres Ponts al Prepirineu. Aquesta nova espècie, que ha aparegut després de la revisió d'antic material d'herbari, ha estat descrita gràcies a l'exploració i recol·lecció d'espècimens al congost de Tres Ponts, a l'estudi morfològic i anatòmic de tots els òrgans de la planta i a l'estudi del seu ADN. Finalment, aquests estudis han portat els investigadors a determinar que aquesta és una espècie diferent de les altres plantes del mateix gènere. Aquesta investigació s'ha fet en col·laboració amb científics de l'Institut Botànic de Barcelona (IBB-CSIC-ICUB) i la Università degli Studi di Sassari (UniSS) de Sardegna.Un grupo de investigadores de la UAB ha descrito una nueva especie de planta, llamada Centaurea tripontina, en la zona del desfiladero de Tres Ponts en el Prepirineo. Esta nueva especie, que ha aparecido tras la revisión de antiguo material de herbario, ha sido descrita gracias a la exploración y recolección de especímenes en el desfiladero de Tres Ponts, al estudio morfológico y anatómico de todos los órganos de la planta y al estudio de su ADN. Finalmente, estos estudios han llevado a los investigadores a determinar que ésta es una especie diferente de las otras plantas del mismo género. Esta investigación se ha realizado en colaboración con científicos del Instituto Botánico de Barcelona (IBB- CSIC-ICUB) y la Università degli Studi di Sassari (Unis) de Sardegna

    Búsqueda de interactores de QQS, proteína de un gen huérfano de Arabidopsis que está relacionada con el pH intracelular y el metabolismo de almidón, mediante dos técnicas de Doble Híbrido

    Full text link
    [ES] Datos previos de microarray de los mutantes simples de pérdida de función de las dos principales isoformas de la H+-ATPasa, aha1-6 y aha2-4, ponen en evidencia QQS, él único gen que baja sensiblemente su expresión en ambos mutantes (Haruta et al., 2012). Además, nuestras primeras investigaciones de la línea transgénica pQQS::QQS-GFP de Arabidopsis tratadas a distintos pHs, nos indican que QQS varía mucho su expresión: aumenta en ambientes alcalinos y desaparece su señal en ambientes ácidos. Por último, nuestros western blots (con anticuerpos contra la H+ATPasas) de la línea de QQS RNAi, comparados con los adecuados controles, indican que QQS puede ser un factor directo o indirecto de la inhibición de la expresión de la H+ATPasa. Este gen, que codifica para una pequeña proteína citosolica de 59 aminoacidos, no presenta dominios conocidos y está presente solo en las especies de Arabidopsis y Brassica rapa (Li et al., 2009). Para seguir la investigación adelante, queremos descubrir cuáles son sus dianas mediante la técnica de rastreo de doble híbrido contra una biblioteca de cDNA de Arabidopsis (Németh et al., 1998). Clonaremos el gen QQS en un plásmido para usarlo de cebo o "bait" y se trasformará en levadura, para luego realizar el rastreo de proteínas que interaccionan con la nuestra a partir de la biblioteca de cDNA. Tampoco podemos excluir que QQS pueda interaccionar directamente con la H+-ATPasa, por lo que probaremos como control positivo solo la zona C terminal de la bomba protónica. También se realizará un doble híbrido específico para proteínas de membranas (sistema de la compañia Dualsystem Biotech). Hay evidencias en nuestro laboratorio, que líneas de perdida de función de 14-3-3 de Arabidopsis, presenten un nivel de expressión de la H+-ATPasa más bajo, no obstantes estos genes no codifiquen para factores de transcripción. En este tipo de doble híbrido usaremos AHA2 como bait y QQS como prey. Mientras un gen de la familia 14-3-3, lo emplearemos de prey para ser nuestro control positivo. Los resultados pueden darnos la clave para descubrir un nuevo mecanismo que controla la H+-ATPasa y su efecto en el pH intracelular.[EN] Previous data from microarrays of the simple knock-out mutants of the main isoforms of PM H+ - ATPase, aha1-6 and aha2-4, evidence that QQS is the only gene which is downregulated in both cases. Additionally, expression data from our laboratory suggests that QQS is antagonistic with respect to PM H+ -ATPases. In order to support these results, the expression of QQS was assessed with fluorescence microscopy at different pH values in the Arabidopsis transgenic line pQQS::QQS-GFP. The results showed an increase of the expression at basic pH values, whereas the fluorescence disappeared at acidic values. Furthermore, the QQS RNAi line was Western blotted using different antibodies against the PM H+ - ATPase, showing that QQS may act as a direct or indirect inhibitor of the expression of PM H+ - ATPases. QQS encodes for a small cytosolic protein of only 59 amino acids, does not show any known domains and is not present in closely related species such as Arabidopsis lyrata or Brassica napus. To investigate its targets, a yeast-two hybrid screening was carried out against an Arabidopsis cDNA library. QQS was cloned in a bait plasmid and was co-transformed with the cDNA library in yeast to perform the screening. The most promising interacting protein is At1g70470, a membrane protein of unknown function and without any bibliographic information. As a direct interaction between QQS and PM H+ -ATPase could not be excluded, a specific yeast-two hybrid assay for membrane proteins was conducted. In this case, the PM H+ -ATPase AHA1 was used as bait, while QQS was the prey protein. The results proved that both proteins interact directly, providing a new control mechanism of the PM H+ -ATPases and intracellular pH.Sáez Sáez, J. (2016). Búsqueda de interactores de QQS, proteína de un gen huérfano de Arabidopsis que está relacionada con el pH intracelular y el metabolismo de almidón, mediante dos técnicas de Doble Híbrido. http://hdl.handle.net/10251/68583.TFG

    Scanning electrochemical microscopy for the analysis and patterning of graphene materials: A review

    Full text link
    [EN] Graphene and related materials have recently emerged as outstanding materials due to a range of properties such as high mechanical strength, high electron mobility, thermal conductivity, etc. Due to their high surface area and conductivity, graphene materials have also been used for electrochemical applications such as supercapacitors, batteries, sensors, etc. Therefore, the characterization of the electroactivity of graphene materials is necessary and different electrochemical techniques such as cyclic voltammetry and electrochemical impedance spectroscopy have been widely used for this purpose. Scanning electrochemical microscopy has appeared as a unique technique that can be used to test electron transfer kinetics, electroactivity and conductivity of these materials. Even patterns can be created on graphene materials by this technique, This review aims to compile the different works performed with graphene materials and scanning electrochemical microscopy technique and provide new perspectives into the analysis of graphene materials using this technique. (C) 2016 Elsevier B.V. All rights reserved.Authors wish to thank to the Spanish Ministerio de Ciencia e Innovacion (contract MAT2016-77742-C2-1-P) for the financial support. J. Molina is grateful to the Conselleria d'Educacio, Formacio i Ocupacio (Generalitat Valenciana) for the Programa VALi+D Postdoctoral Fellowship (APOSTD/2013/056). Tim Vickers is gratefully acknowledged for help with the English revision.Molina Puerto, J.; Fernández Sáez, J.; Cases Iborra, FJ. (2016). Scanning electrochemical microscopy for the analysis and patterning of graphene materials: A review. Synthetic Metals. 222:145-161. https://doi.org/10.1016/j.synthmet.2016.10.019S14516122
    corecore