533 research outputs found

    Mergeable weighted majority games and characterizations of some power indices

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    In this paper, we introduce a notion of mergeable weighted majority games with the aim of providing the first characterization of the Colomer–Martínez power index (Colomer and Martínez in J Theor Polit 7(1):41–63, 1995). Furthermore, we define and characterize a new power index for the family of weighted majority games that combines ideas of the Public Good (Holler in Polit Stud 30(2):262–271, 1982) and Colomer–Martínez power indices. Finally, we analyze the National Assembly of Ecuador using these and some other well-known power indicesWe would like to thank Balbina V. Casas-Méndez and two anonymous referees for their valuable comments. This work is part of the R+D+I project grants MTM2017-87197-C3-2-P, MTM2017-87197-C3-3-P, PID2021-124030NB-C32, and PID2021-124030NB-C33, that were funded by MCIN/AEI/10.13039/501100011033/ and by “ERDF A way of making Europe”/EU. This research was also funded by Grupos de Referencia Competitiva ED431C-2020/03 and ED431C-2021/24 from the Consellería de Cultura, Educación e Universidades, Xunta de Galicia. Open Access funding provided thanks to the CRUE-CSIC agreement with Springer NatureS

    Comparing risk-weighted assets: the importance of supervisory validation processes

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    Artículo de revistaThis article analyses the problems of using the risk-weighted assets (RWA) density ratio – defined as the ratio of RWA to total assets – to make comparisons across banks, as is frequently done by banks themselves and analysts. An international comparison is made of 16 European banks, based on public information, from which it is concluded that a significant part of the differences in RWA density are a consequence of differences in the type of business involved. In particular, the greater the weight of credit risk in a bank’s balance sheet the higher will be its RWA density. We propose alternative RWA density ratios and illustrate them with the results for Spanish banks using confidential data. We show that public information cannot be sufficiently detailed to enable differences across banks arising from their risk profiles to be distinguished from others attributable, for example, to different interpretations of solvency rules by banks or supervisors. Therefore, the supervisory review process and the progress in its inter-jurisdictional harmonisation are especially important. The paper concludes with a review of the process used by the Banco de España for the supervisory validation of Internal Ratings Based (IRB) approaches for credit risk

    Cooperation on capacitated inventory situations with fixed holding costs

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    [Abstract] In this paper we analyze a situation in which several firms deal with inventory problems concerning the same type of product. We consider that each firm uses its limited capacity warehouse for storing purposes and that it faces an economic order quantity model where storage costs are irrelevant (and assumed to be zero) and shortages are allowed. In this setting, we show that firms can save costs by placing joint orders and obtain an optimal order policy for the firms. Besides, we identify an associated class of costs games which we show to be concave. Finally, we introduce and study a rule to share the costs among the firms which provides core allocations and can be easily computed.Ministerio de Ciencia e Innovación; MTM2011-23205Galicia. Consellería de Economía e Industria; INCITE09-207-064-PRComunidad Valenciana. Generalidad; ACOMP/2014Ministerio de Ciencia e Innovación; MTM2011-27731-C0

    Flapless implant surgery: a review of the literature and 3 case reports

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    Since the 1970s, modern Implantology is based on a concept of surgery with flap elevation. Gradually, several clinical trials demonstrated that a mid-crestal incision gives similar success rates compared to those obtained using the classical protocol. However, over the past decade in medicine it has been established the concept of minimally invasive surgery, consisting in taking advantage of advancements experienced in diagnostic techniques and specific surgical instruments, to perform surgical procedures infringing as less damage as possible to the patient The present work aims to produce a thorough review of the literature published on the field of Implantology with flapless surgery, to determine the current scientific evidence of the technique, along with illustrating the results with different clinical cases. After presenting the clinical cases, and the review of literature, we can say that flapless surgeries should be restricted to well-selected cases in which a proper clinical and radiological planning has been made. Patients treated with anticoagulant drugs or medically compromised equally can get benefitted by this minimal invasion technique

    Influencia de la adición de estaño en el proceso de precipitación en una aleación de Cu-Ni-Zn

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    Mediante calorimetría diferencial de barrido (DSC), medidas de microdureza y microscopía electrónica de transmisión de alta resolución (HRTEM) se estudió la influencia de la adición de 1,1% en peso de estaño en el endurecimiento por precipitación en una aleación de Cu-11Ni-20Zn (% en peso). Las curvas calorimétricas de la aleación ternaria, en el intervalo de temperaturas analizado, muestran la presencia de dos reacciones exotérmicas asociadas al desarrollo de orden de corto alcance, favorecidas por la migración de vacantes. En cambio, en la aleación cuaternaria se observa una reacción exotérmica y una endotérmica, asociadas a la formación y disolución de precipitados de Cu2NiZn, respectivamente. Se ha demostrado que una adición de 1,1% de estaño juega un papel importante en la formación de los precipitados de Cu2NiZn, responsables del endurecimiento por precipitación de la aleación ternaria.Influence of tin additions on the precipitation processes in a Cu-Ni-Zn alloys. The influence of 1.1 wt% tin additions on the precipitation hardening of Cu-11 wt% Ni-20 wt% Zn alloy was studied by Differential Scanning Calorimetry (DSC), microhardeness measurements and High Resolution Transmission Electron Microscopy (HRTEM). The calorimetric curves, in the range of temperatures analyzed, show the presence of two exothermic reactions in the ternary alloy, associated to the short-range-order development assisted by migration of excess vacancies. On the other hand, one exothermic and one endothermic reaction are observed in the quaternary alloy, associated to the formation and dissolution of Cu2NiZn precipitates, respectively. It has been show that an addition of 1.1% tin plays an important role in the formation of Cu2NiZn precipitates, responsible for the precipitation hardening of the ternary alloyFondo Nacional de Desarrollo Científico y Tecnológico FONDECYT 114078

    Self-cleaning durability assessment of TiO2/SiO2 photocatalysts coated concrete: Effect of indoor and outdoor conditions on the photocatalytic activity

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    A self-cleaning nanostructured TiO2 coating has demonstrated the capacity to mitigate undesired effects from air pollution. Not only it reduces the deterioration of building materials but may also prevent certain pollution-related human health problems. In this study, mesoporous TiO2/SiO2 photocatalysts were synthesized in order to produce self-cleaning and long-lasting coatings that meet the necessary requirements for outdoor applications. The synthesized products were sprayed on concrete substrates and their self-cleaning and air depolluting capabilities were evaluated. The former one as a function of methylene blue (MB) and soot degradation and the latter, according to nitrogen oxides reduction. The coatings proved to have high photocatalytic activity, and their efficiency was enhanced as TiO2 loadings were increased. Thus, after the first 60 min of their irradiation by UV–vis light, the photocatalysts ST1 and S4T had removed 79% and 95% of the MB, respectively. These coatings presented particulate surfaces that provided more surface area and porosity, which are key factors for a high photocatalytic activity. Moreover, the same samples after 104 h of irradiation exhibited 38% and 49% conversion of total NO, respectively. While E503, a commercially available photocatalyst, produced coating cracked surfaces and a total MB degradation of just 50% after 60 min of irradiation as well as 35% of NO conversion after 104 h of irradiation. The TiO2/SiO2 coatings’ photocatalytic efficacy remained practically invariable after four months of exposure to real-life conditions and three MB degradation cycles. After the outdoor durability tests, the coated surfaces exhibited a practically unchanged structure, which confirms their long-lasting efficiency. © 2022 The AuthorsThis work has been supported by the Spanish Government MAT2017-84228-R (MINECO/AEI//FEDER, UE) and PID2020- 115843RB-I00/AEI/10.13039/501100011033 . This work has been co-financed by the European Union under the 2014–2020 ERDF Operational Programme and by the Department of Economic Transformation, Industry, Knowledge, and Universities of the Regional Government of Andalusia . Project reference: FEDER-UCA18-106613

    The attached testimoy in the colombian system

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    En este artículo se reflexiona sobre el empleo del testimonio adjunto como mecanismo de incorporación de una declaración anterior a juicio dentro del sistema penal acusatorio colombiano. El documento consta de cuatro apartados. Primero se abordan los aspectos generales sobre el testimonio adjunto en Colombia, es decir, se identificarán los antecedentes, el concepto y la base jurídica en el sistema normativo nacional. Luego se plantea el desarrollo jurisprudencial del testimonio adjunto, con indicación de sus reglas, la oportunidad y los requisitos de su aducción. Después se exponen algunas de las problemáticas que conlleva la aplicación del testimonio adjunto en Colombia. Para ello se analiza la figura de cara al debido proceso y se cuestiona la viabilidad de descubrir y solicitar el testimonio adjunto antes del juicio oral. Finalmente, se exponen los hallazgos y resultados del proceso de reflexión.Universidad Libre Seccional Pereira -- Facultad de Derecho, Ciencias Políticas y Sociales -- Especialización en Derecho PenalThis article reflects on the use of attached testimony as a mechanism for incorporating a statement prior to trial within the Colombian accusatory criminal system. The document consists of four sections. First, the general aspects of the attached testimony in Colombia are addressed, that is, the background, concept and legal basis in the national regulatory system will be identified. Then the jurisprudential development of the attached testimony is raised, indicating its rules, the opportunity and the requirements of its adduction. Afterwards, some of the problems that the application of the attached testimony in Colombia entails are exposed. To do this, the figure facing due process is analyzed and the feasibility of discovering and requesting the attached testimony before the oral trial is questioned. Finally, the findings and results of the reflection process are exposed

    Influence of gold nanoparticles size for photocatalytic NO oxidation in low loading Au/TiO2 catalysts

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    Gold nanoparticles (AuNPs) supported on TiO2 are one of the most investigated photocat-alysts, however, the positive effect of AuNPs size reduction on Au/TiO2 activity is clear for conventional catalysis, but this relationship not strictly happens in photocatalysis. The present work investigates how small changes in the lower size range of AuNPs can affect the Au/TiO2 photoactivity in order to maximize the performance of photocatalysts with low metal loadings (<1 wt%). Precipitation-deposition methods and a speciation-controlled incipient wetness impregnation (ScIWI) method have been employed for preparing Au/TiO2 photocatalysts that exhibited a NOx elimination capacity significantly higher than pristine TiO2. Comparing the photocatalysts, ScIWI method achieved the highest gold dispersion and Au-TiO2 contact perimeter providing the most active photocatalysts, confirming the positive effect of AuNPs size reduction in the average sizes around 2 nm. In addition, on the basis of the results obtained, it has been proposed that the adsorption of nitrogen oxides species on gold has a relevant role on the NO photooxidation process.(c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)

    Innovación Docente en Historia Económica en el EEES

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    El Proyecto de Innovación Docente se aplicó sobre 450 alumnos de la asignatura de Historia Económica en el primer curso del Grado de Finanzas y Contabilidad. En esta asignatura se había utilizado tradicionalmente una metodología basada en clases magistrales con el apoyo de lecturas y materiales complementarios. El proyecto docente introducía una metodología de enseñanza mixta utilizando la plataforma virtual de la Universidad de Sevilla. A través de esta plataforma se realizaron actividades presenciales y también de e-learning en la web. La temática principal de estas actividades se centró en las crisis económicas. Esto se concretó a partir de estudio de casos: la crisis finisecular del siglo XIX, la crisis de 1929 y las crisis de finales del siglo XX y principios del XXI (crisis del petróleo de 1973, crisis financiera de los años 90 y la crisis económica actual). A través del material aportado por el profesor en la red y en las actividades complementarias presenciales (prensa, lecturas de historia económica y documentales) se establecen las causas, efectos y aspectos comunes y diferenciales de estas crisis.The Teaching Innovation Project was applied to 450 students of the Subject of Economic History of the first year of the Finance and Accounting Degree. This topic had used to be a traditional method based on master classes with the support of complementary readings and dossiers. Teaching project introduced a blended learning using the University of Seville web site. Through this platform and attending classes were also e-learning. The main topic of these activities are focused on the economic crisis with cases studies: the crisis of 1873, the Great Depression of 1929, the crisis of 1973 oil crisis, financial crisis 90’s years and the current economic crisis. Through the network materials, and exercises in class (press, reading of economic history and documentaries are established the causes, effects and common and differents aspects of these crisis
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