683 research outputs found

    Sistemas financieros y financiación de las PYMES en España y Europa

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    Tras la excesiva dependencia del crédito bancario vivida históricamente en Europa los sistemas financieros evolucionan hacia una orientación de mercado y un mayor equilibrio entre la financiación bancaria y no bancaria, todo ello impulsado por la puesta en marcha de mercados alternativos de renta variable y de renta fija de mayor accesibilidad para empresas de menor tamaño. Además, distintas fuentes de financiación tradicionales vuelven a retomar impulso tras la crisis financiera de 2008, al tiempo que otros métodos alternativos de financiación se posicionan como necesarios para la obtención de recursos por parte de pequeños negocios.Following the over-reliance on bank credit historically experienced in Europe, financial systems have evolved towards market orientation and a better balance between bank and non-bank financing, all driven by the launch of alternative equity and fixed income markets of greater accessibility for smaller companies. In addition, a number of traditional sources of funding are regaining momentum following the financial crisis of 2008, while other alternative financing methods are positioned as necessary to obtain resources from small businesses.Universidad de Sevilla. Grado en Administración y Dirección de Empresa

    Coarse-Grained Simulations of Release of Drugs Housed in Flexible Nanogels: New Insights into Kinetic Parameters

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    Funding: This research was funded by “Consejería de Economía, Conocimiento, Empresas y Universidad, Junta de Andalucía, Programa Operativo FEDER Andalucía 2014-2020”, grant number P20_00138 as well as “Ministerio de Ciencia e Innovación”, grant numbers PID2020-116615RA-I00 and PGC2018-098770-B-I00.The diffusion-controlled release of drugs housed in flexible nanogels has been simulated with the help of a coarse-grained model that explicitly considers polymer chains. In these in silico experiments, the effect of its flexibility is assessed by comparing it with data obtained for a rigid nanogel with the same volume fraction and topology. Our results show that the initial distribution of the drug can exert a great influence on the release kinetics. This work also reveals that certain surface phenomena driven by steric interactions can lead to apparently counterintuitive behaviors. Such phenomena are not usually included in many theoretical treatments used for the analysis of experimental release kinetics. Therefore, one should be very careful in drawing conclusions from these formalisms. In fact, our results suggest that the interpretation of drug release curves in terms of kinetic exponents (obtained from the Ritger–Peppas Equation) is a tricky question. However, such curves can provide a first estimate of the drug diffusion coefficient.Consejería de Economía, Conocimiento, Empresas y Universidad, Junta de Andalucía, Programa Operativo FEDER Andalucía 2014-2020, grant number P20_00138Ministerio de Ciencia e Innovación, grant numbers PID2020-116615RA-I00 and PGC2018-098770-B-I0

    ¿Normal o patológico? El enfermo imaginario en tierra de nadie

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    Is the boundary between the normal and the pathological real or fiction? Are health and disease just a matter of fact or are they value-laden? Here we present some examples of how alleged diseases can be invented and propagated by the industry (disease mongering) or by the methodology of medical science itself. We show that the boundary between health and disease is blurred and depends on individual and social representations, culture relative ways of categorising things and people, and by the society’s degree of medicalisation. However, we do not mean that it is not real, rather that it is more complex than expected, as the subjectivity of social constructions and individual experiences makes them no less real. Finally, we conclude that health and disease belong to both objective and subjective kinds of reality, so the fictional can be real.¿Es la frontera entre lo normal y lo patológico una realidad o una ficción? ¿Es la enfermedad solo una cuestión de hecho o también de valores? Presentamos aquí algunos ejemplos de cómo supuestas enfermedades pueden ser inventadas y difundidas con fines de lucro (disease mongering) o por la propia dinámica de la investigación médica. Mostramos cómo la frontera entre la salud y la enfermedad es borrosa y está bajo la influencia de representaciones individuales y sociales, de modos de categorización relativos a cada cultura, y del grado de medicalización de la sociedad. Ahora bien, estas consideraciones no le restan realidad sino que le añaden complejidad, porque las construcciones sociales y las experiencias individuales, por ser subjetivas, no son menos reales. Concluimos que la salud y la enfermedad pertenecen simultáneamente a diferentes tipos de realidad, tanto objetivos como subjetivos, y que lo ficticio puede ser real

    Téléologie et fonctions en biologie. Une approche non causale des explications téléofonctionnelles

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    This dissertation is focused on teleology and functions in biology. More precisely, it focuses on the scientific legitimacy of teleofunctional attributions and explanations in biology. It belongs to a multi-faceted debate that can be traced back to at least the 1970s. One aspect of the debate concerns the naturalization of functions. Most authors try to reduce, translate or explain functions and teleology in terms of efficient causes so that they find their place in the framework of the natural sciences. Our approach here is radically different, as we question the premise that teleological explanations are disguised causal explanations. On the contrary, we defend that they are acceptable in natural sciences and in biology in particular. We challenge the idea that teleological explanations are immature causal explanations, as well as the idea that teleology and functions are some sort of intentional explanations. We therefore reject the accusations of anthropomorphism, vitalism and finalism. On the contrary, we defend that teleology, causality and intentionality correspond to different, autonomous and complementary modes of representation of the outside world. ———[FRANÇAIS]——— Ce travail de thèse porte sur la téléologie et les fonctions en biologie. Plus précisément, il porte sur la légitimité scientifique des attributions et des explications téléofonctionnelles en biologie. Il s’inscrit dans le cadre d’un débat à plusieurs facettes que l’on peut faire remonter au moins jusqu’aux années 1970 et qui est encore très actif aujourd’hui. L’un des aspects du débat porte sur la naturalisation des fonctions, c’est-à-dire sur la manière de les réduire, de les traduire ou de les expliciter en termes de causes efficientes de sorte qu’elles trouvent leur place dans le cadre des sciences de la nature. Notre approche ici est radicalement différente, car nous remettons en question la prémisse selon laquelle les explications téléologiques seraient des explications causales déguisées. Nous défendons au contraire qu’elles sont acceptables en tant que telles aussi bien de façon générale que dans le domaine scientifique et en particulier en biologie. De façon générale, nous remettons en question l’idée selon laquelle la pensée téléologique serait une pensée causale immature, ainsi que sa dépendance présumée vis-à-vis de la psychologie, c’est-à-dire de l’intentionnalité. Nous rejetons donc les accusations d’anthropomorphisme, de vitalisme et de finalisme formulées contre elle. Nous défendons au contraire que la téléologie, la causalité et l’intentionnalité correspondent à des modes différents, autonomes et complémentaires de représentation du monde extérieur

    Micromechanics of fully lamellar TiAl alloys

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    Fully lamellar gamma titanium aluminides are very promising materials for aerospace applications, due to their increased thrust-to-weight ratios and improved efficiency under aggressive environments at temperatures up to 750 ºC. For that reason, they are projected to replace the heavier Ni- base superalloys currently used for low pressure turbine (LPT) blades manufacturing. However, their ductility is limited due to their inherent anisotropy, associated to the lamellar microstructure. The objective of this work was to study the mechanical response of single colonies of polycrystalline γ-TiAl, as a function of layer thickness and layer orientation, and to relate this mechanical response with the operative deformation mechanisms. With this aim, micropillars with lamellae oriented at 0º, 45º and 90º with respect to the loading direction were compressed at room temperature and elevated temperature. The results revealed a large plastic anisotropy, that was rationalized, based on slip/twin trace analysis, according to the relative orientation of the main operative deformation modes with respect to the lamellar interfaces. Loading at 45º resulted in the activation of soft longitudinal deformation modes, where both the slip plane and the slip direction were parallel to the interfaces, and therefore, little interaction of dislocations with lamellar interfaces is expected. At 0º loading, deformation was mainly accommodated by harder mixed deformation modes (with an oblique slip plane but a slip direction parallel to the lamellar interfaces), although the lamellar interfaces seemed to be relatively transparent to slip transfer. On the contrary, 90º loading represented the hardest direction and deformation was accommodated by the activation of transverse deformation modes, confined to individual lamellae, together with longitudinal modes that were activated due to their softer nature, despite their very small Schmid factors. Finally, a thorough study of pillar size effects revealed that the results were insensitive to pillar size for dimensions above 5 mm. The results can therefore be successfully applied for developing mesoscale plasticity models that capture the micromechanics of fully lamellar TiAl microstructures at larger length scales Additionally, microtensile specimens were also milled out of single colonies and in-situ tested in the SEM, to study the role of interlamellar interfaces on the plastic deformation and fracture under tension. EBSD was used before and after the test to study the role of different type of interfaces (true twin, pseudo twin and order variant) on slip/twin transfer. This study emphasizes the complexity of the micromechanics of fully lamellar TiAl alloys, where the activation of different deformation modes is strongly affected, not only by the lamellar orientation, but also by the character of the interfaces between the different lamellae. References A.J. Palomares, M.T. Pérez-Prado, J.M. Molina-Aldareguia, Acta Mater. 123 (2017) 102-114 A.J. Palomares, I. Sabirov, M.T. Pérez-Prado, J.M. Molina-Aldareguia, Scripta Mater. 139 (2017) 17-2

    Fertility Decisions: The Role of Divorce Laws, Culture and Its Impact on Marital Status

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    Esta tesis doctoral sigue un análisis económico para estudiar las decisiones de la pareja relativas a la fertilidad, un importante campo de estudio dentro de la Economía de la Familia, mediante el desarrollo de tres líneas de investigación. En primer lugar, analizamos el efecto de las reformas en las leyes de divorcio que se produjeron en Europa sobre las decisiones de fertilidad, para lo que explotamos la historia legislativa de la liberalización del divorcio en Europa, encontrando que las reformas de las leyes de divorcio tienen un efecto negativo y permanente sobre la fertilidad. En segundo lugar, usamos datos de inmigrantes de segunda y superior generación que viven en los Estados Unidos para estudiar el impacto de la cultura en las decisiones de fertilidad de las mujeres adolescentes, para lo que explotamos las variaciones en las tasas de fertilidad de las mujeres adolescentes por país de origen de sus antepasados. Los resultados muestran que la cultura tiene un impacto cuantitativamente significativo sobre las decisiones de fertilidad de las mujeres adolescentes. Finalmente, estudiamos el efecto del número de hijos concebidos durante el primer matrimonio sobre el riesgo de ruptura matrimonial usando un enfoque de variables instrumentales. Los resultados confirman el efecto disuasorio de los hijos en la probabilidad de divorcio de la pareja. Mediante esta tesis integrada dentro de la Economía de la Familia, pretendemos mejorar el conocimiento de las causas y las consecuencias de las decisiones de fertilidad de las parejas, complementando y contribuyendo a la literatura existente sobre fertilidad
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