7,350 research outputs found

    Assessment of heritage rammed-earth buildings. The Alcázar of King Don Pedro I (Spain).

    Get PDF
    The conservation and maintenance of earthen buildings is crucial, especially when dealing with heritage sites. This normally involves considerable effort in preliminary studies, which must be well planned in order to efficiently manage any restoration. This case study proposes a methodology to briefly assess the current state of a historical rammed-earth wall, to bring to light specific information regarding approaches for subsequent studies or decisions. This methodology is based on the study of damage and risk as a tool to swiftly discern critical areas or issues needing immediate attention. The procedure is illustrated on an outstanding heritage building: the Alcázar of King Don Pedro I in Carmona (Seville, Spain). Our conclusions confirm that this methodology constitutes an efficient and straightforward means to obtain not only a preliminary assessment of rammed-earth walls, but also objective and useful criteria for decision-makers

    Implicaciones humanitarias de la contratación de empresas militares privadas (PMC) por parte de los Estados. Estudio de caso; Estados Unidos y Blackwater en Irak (2003-2007)

    Get PDF
    La presente investigación tiene como finalidad analizar las implicaciones humanitarias de la participación de las Compañías Militares Privadas (PMC) contratadas por los Estados en escenarios de conflicto, a partir del caso de Blackwater y Estados Unidos en Irak (2003-2007), con el fin de mostrar a través de algunos hechos específicos como el acaecido en la plaza Al Nisour los vacíos existentes en la regulación de sus actividades. Frente a estos hechos se muestra como la Comunidad Internacional ha tratado de avanzar en la creación de un régimen internacional que las controle, sin embargo, como se evidencia a lo largo de este escrito la falta de compromiso por parte de los Estados ha hecho que esta tarea se vea obstaculizada y por lo tanto la actuación de estas compañías se encuentra aún en una zona jurídica gris.This investigation aims to analyze Private Military Companies’ participation in conflict sceneries, using the specific case of Blackwater in Irak hired by the United States (2003-2007). Achieving the goal of trying to explain the blank spaces in current law regulations trough some incidents such as the one developed in Al Nisour square. According to this, the article also reflects the efforts made by the international community and the lack of States solid participation, turning this into a difficult to solve situation that carries many grey jurisdiction areas.Universidad del Rosari

    Discrimination of milks with a multisensor system based on layer-by-layer films

    Get PDF
    Producción CientíficaA nanostructured electrochemical bi-sensor system for the analysis of milks has been developed using the layer-by-layer technique. The non-enzymatic sensor [CHI+IL/CuPcS]2, is a layered material containing a negative film of the anionic sulfonated copper phthalocyanine (CuPcS) acting as electrocatalytic material, and a cationic layer containing a mixture of an ionic liquid (IL) (1-butyl-3-methylimidazolium tetrafluoroborate) that enhances the conductivity, and chitosan (CHI), that facilitates the enzyme immobilization. The biosensor ([CHI+IL/CuPcS]2-GAO) results from the immobilization of galactose oxidase on the top of the LbL layers. FTIR, UV–vis, and AFM have confirmed the proposed structure and cyclic voltammetry has demonstrated the amplification caused by the combination of materials in the film. Sensors have been combined to form an electronic tongue for milk analysis. Principal component analysis has revealed the ability of the sensor system to discriminate between milk samples with different lactose content. Using a PLS-1 calibration models, correlations have been found between the voltammetric signals and chemical parameters measured by classical methods. PLS-1 models provide excellent correlations with lactose content. Additional information about other components, such as fats, proteins, and acidity, can also be obtained. The method developed is simple, and the short response time permits its use in assaying milk samples online.Ministerio de Economía, Industria y Competitividad - Fondo Europeo de Desarrollo Regional (project AGL2015-67482-R)Junta de Castilla y Leon - Fondo Europeo de Desarrollo Regional (project VA-011U16)Junta de Castilla y León (grant BOCYL-D-4112015-9

    Causes and success of brand deletions. The role of brand orientation

    Get PDF
    La eliminación de una marca es una decisión crítica dentro de la estrategia de marketing de una empresa. Pese a que en los últimos años muchas organizaciones han tomado este tipo de decisión y han acometido drásticos programas de eliminación de marcas, la literatura sobre este tema es muy escasa y fragmentada, y son múltiples las cuestiones que se deben abordar. Concretamente, en este trabajo nos proponemos examinar la influencia de las causas de eliminación de una marca –previamente clasificadas en proactivas y reactivas– en el éxito de la decisión. Además, exploramos el efecto que la orientación a la marca tiene en la mayor o menor ocurrencia de eliminaciones por causas proactivas o reactivas. Implícitamente, en el trabajo proponemos que la orientación a la marca tendrá un doble efecto indirecto positivo en el éxito de una eliminación. En primer lugar, a través de incremento de eliminaciones exitosas que ocurren por causas proactivas y, en segundo, por la reducción de eliminaciones no exitosas que sobrevienen por causas reactivas. La propuesta investigadora que realizamos se testa sobre una muestra de 155 casos de eliminación de marca. Los análisis preliminares indican que la orientación a la marca contribuye al éxito a través de la adopción de eliminaciones enfocadas en el aprovechamiento de oportunidades de la marca, tales como un mayor ajuste estratégico o unos menores costes de oportunidad. Además, la orientación a la marca previene de realizar eliminaciones simplemente por causas problemáticas, eliminaciones que no acaban arrojando grandes resultados.Brand deletion (BD) is a critical decision within a firm’s marketing strategy. Despite in recent years many organizations have pruned their brand portfolios and undertaken drastic BD programs, the literature on this topic is extremely scarce and fragmented, and several issues of BD can be investigated. This research is primarily concerned with the study of the impact of BD causes –previously classified as proactive versus reactive– on BD success. In addition, we explore the effect of the firm’s brand orientation on the occurrence of deletions by proactive versus reactive causes. Implicitly, we suggest that brand orientation will have a double positive indirect effect on BD success: first, through the increase of successful BDs due to proactive causes and, second, by the reduction of unsuccessful BDs precipitated by reactive causes. Our research proposal is tested on a sample of 155 cases of BD. Preliminary findings indicate that brand orientation contributes to the BD success through the adoption of BDs focused on taking advantage of brand opportunities, such as searching for a better strategic fit or avoiding opportunity costs. Besides, brand orientation prevents deletions due to merely problematic causes, deletions that, after all, do not generate success

    Electrochemical sensors modified with combinations of sulfur containing phthalocyanines and capped gold nanoparticles: A study of the influence of the nature of the interaction between sensing materials

    Get PDF
    Producción CientíficaVoltametric sensors formed by the combination of a sulfur-substituted zinc phthalocyanine (ZnPcRS) and gold nanoparticles capped with tetraoctylammonium bromide (AuNPtOcBr) have been developed. The influence of the nature of the interaction between both components in the response towards catechol has been evaluated. Electrodes modified with a mixture of nanoparticles and phthalocyanine (AuNPtOcBr/ZnPcRS) show an increase in the intensity of the peak associated with the reduction of catechol. Electrodes modified with a covalent adduct-both component are linked through a thioether bond-(AuNPtOcBr-S-ZnPcR), show an increase in the intensity of the oxidation peak. Voltammograms registered at increasing scan rates show that charge transfer coefficients are different in both types of electrodes confirming that the kinetics of the electrochemical reaction is influenced by the nature of the interaction between both electrocatalytic materials. The limits of detection attained are 0.9 × 10−6 mol∙L−1 for the electrode modified with the mixture AuNPtOcBr/ZnPcRS and 1.3 × 10−7 mol∙L−1 for the electrode modified with the covalent adduct AuNPtOcBr-S-ZnPcR. These results indicate that the establishment of covalent bonds between nanoparticles and phthalocyanines can be a good strategy to obtain sensors with enhanced performance, improving the charge transfer rate and the detection limits of voltammetric sensors.Ministerio de Economía, Industria y Competitividad - Fondo Europeo de Desarrollo Regional (projects RTI2018-097990-B-I00 / CTQ2017-87102-R)Junta de Castilla y Leon - Fondo Europeo de Desarrollo Regional (project VA275P18

    Aplicación y uso de la web 2.0 y de las redes sociales en la comunicación científica especializada: del marketing viral al usuario activo

    Get PDF
    Analizamos el uso que hacen las entidades científicas españolas de la web 2.0 parala difusión de sus actividades e informaciones científico-técnicas. Para ello, elegimoscomo marco temporal la Semana de la Ciencia, el mayor evento de comunicacióncientífica anual que se celebra en España. Partiendo de la hipótesis de que enevento la red se convierte en el principal canal de difusión para que el público esté alcorriente de las actividades, investigamos las estrategias push y pull para la captaciónde públicos y la ampliación del segmento-nicho, a priori demasiado circunscrito a laespecialización, hasta su extensión a una audiencia más amplia y, en consecuencia,más generalista. Ha resultado especialmente interesante la aplicación que estosorganismos han hecho en 2009 de la web 2.0 y de las redes sociales para incrementarsus posibilidades de comunicación mediante la aplicación de técnicas virales y debuzz, con el objetivo de que los públicos adoptasen una actitud proactiva de difusiónde la ciencia entre perfiles de usuarios que comparten expectativas y aspiracionesvinculadas al mundo de la ciencia

    The first report of South American edrioasteroids and the paleoecology and ontogeny of rhenopyrgid echinoderms

    Get PDF
    A new species of rhenopyrgid edrioasteroid Rhenopyrgus piojoensis sp. nov. is described form the Silurian (Lower Lud− low) Los Espejos Formation in the Precordillera of Argentina. This species is the first reported edrioasteroid from South America. Rhenopyrgids are widely distributed in Ordovician through Devonian deposits of most continents. Numerous juvenile specimens show that the general bodyplan is organized early in ontogeny and that the pedenculate zone lengthens with age. Phylogenetic analysis shows that rhenopyrgids are more closely related to edrioasterid edrioasteroids such as edrioblastoids and cyathocystids than to pyrgocystid isorophids.Fil: Sumrall, Colin D.. University of Tennessee; Estados UnidosFil: Heredia, Susana Emma. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Investigaciones Mineras; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Rodríguez, Cecilia María. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Investigaciones Mineras; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Mestre García, Ana Isabel. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Investigaciones Mineras; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

    Photosynthetic active radiation, solar irradiance and the CIE standard sky classification

    Get PDF
    Plant growth is directly related to levels of photosynthetic photon flux density, Qp. The improvement of plant-growth models therefore requires accurate estimations of the Qp parameter that is often indirectly calculated on the basis of its relationship with solar irradiation, RS, due to the scarcity of ground measurements of photosynthetic photon flux density. In this experimental campaign in Burgos, Spain, between April 2019 and January 2020, an average value of the Qp/Rs ratio is determined on the basis of measurements at ten-minute intervals. The most influential factor in the Qp/Rs ratio, over and above any daily or seasonal pattern, is the existence of overcast sky conditions. The CIE standard sky classification can be used to establish an unequivocal characterization of the cloudiness conditions of homogeneous skies. In this study, the relation between the CIE standard sky type and Qp/Rs is investigated. Its conclusions were that the Qp/Rs values, the average of which was 1.93 0.15 mol J�����1, presented statistically significant di erences for each CIE standard sky type. The overcast sky types presented the highest values of the ratio, while the clear sky categories presented the lowest and most dispersed values. During the experimental campaign, only two exceptions were noted for covered and partial covered sky-type categories, respectively, sky types 5 and 9. Their values were closer to those of categories classified as clear sky according to the CIE standard. Both categories presented high uniformity in terms of illumination.Spanish Ministry of Science and Innovation, grant number RTI2018-098900-B-I00 and Consejería de Educación, Junta de Castilla y León, grant number BU021G1

    Biosensors Platform Based on Chitosan/AuNPs/Phthalocyanine Composite Films for the Electrochemical Detection of Catechol. The Role of the Surface Structure

    Get PDF
    Producción CientíficaBiosensor platforms consisting of layer by layer films combining materials with different functionalities have been developed and used to obtain improved catechol biosensors. Tyrosinase (Tyr) or laccase (Lac) were deposited onto LbL films formed by layers of a cationic linker (chitosan, CHI) alternating with layers of anionic electrocatalytic materials (sulfonated copper phthalocyanine, CuPcS or gold nanoparticles, AuNP). Films with different layer structures were successfully formed. Characterization of surface roughness and porosity was carried out using AFM. Electrochemical responses towards catechol showed that the LbL composites efficiently improved the electron transfer path between Tyr or Lac and the electrode surface, producing an increase in the intensity over the response in the absence of the LbL platform. LbL structures with higher roughness and pore size facilitated the diffusion of catechol, resulting in lower LODs. The [(CHI)-(AuNP)-(CHI)-(CuPcS)]2-Tyr showed an LOD of 8.55∙10−4 μM, which was one order of magnitude lower than the 9.55·10−3 µM obtained with [(CHI)-(CuPcS)-(CHI)-(AuNP)]2-Tyr, and two orders of magnitude lower than the obtained with other nanostructured platforms. It can be concluded that the combination of adequate materials with complementary activity and the control of the structure of the platform is an excellent strategy to obtain biosensors with improved performances.Ministerio de Ciencia, Innovación y Universidades - Fondo Europeo de Desarrollo Regional (project RTI2018-097990-B-100)Junta de Castilla y Leon - Fondo Europeo de Desarrollo Regional (project VA275P18)Infraestructuras Red de Castilla y León (grant UVA01

    Polymeric foams as the matrix of voltammetric sensors for the detection of catechol, hydroquinone, and their mixtures

    Get PDF
    Producción CientíficaPorous electrodes based on polymethylmethacrylate and graphite foams (PMMA_G_F) have been developed and characterized. Such devices have been successfully used as voltammetric sensors to analyze catechol, hydroquinone, and their mixtures. The presence of pores induces important changes in the oxidation/reduction mechanism of catechol and hydroquinone with respect to the sensing properties observed in nonfoamed PMMA_graphite electrodes (PMMA_G). The electropolymerization processes of catechol or hydroquinone at the electrode surface observed using PMMA_G do not occur at the surface of the foamed PMM_G_F. In addition, the limits of detection observed in foamed electrodes are one order of magnitude lower than the observed in the nonfoamed electrodes. Moreover, foamed electrodes can be used to detect simultaneously both isomers and a remarkable increase in the electrocatalytic properties shown by the foamed samples, produces a decrease in the oxidation potential peak of catechol in presence of hydroquinone, from +0.7 V to +0.3 V. Peak currents increased linearly with concentration of catechol in presence of hydroquinone over the range of 0.37·10−3 M to 1.69·10−3 M with a limit of detection (LOD) of 0.27 mM. These effects demonstrate the advantages obtained by increasing the active surface by means of porous structures.Ministerio de Economía, Industria y Competitividad - Fondo Europeo de Desarrollo Regional (project AGL2015-67482-R)Junta de Castilla y Leon - Fondo Europeo de Desarrollo Regional (project VA-011U16
    corecore