360 research outputs found

    Argumentos ontológicos

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    En este artículo proponemos una revisión a fondo de los argumentos ontológicos clásicos: de Anselmo, Descartes, Spinoza y Leibniz. En la introducción se precisa la noción de argumento ontológico y señalamos la importante distinción que hacemos en lógica entre la validez de un argumento y su solidez, esta última tiene en cuenta no sólo la corrección formal del mismo sino también la verdad de las hipótesis. En las siguientes secciones se analizan por turno los argumentos de Anselmo, Descartes, Spinoza y Leibniz. En todos los casos hemos traducido los pasajes correspondientes del argumento original y formalizado sus hipótesis y conclusión. En algunos casos hemos reconstruido el argumento y destacado como hipótesis todos los enunciados que de hecho se usan en la demostración por parte de los autores en estudio. De esta forma a veces nos separamos de lo que tradicionalmente es considerado el argumento (por ejemplo, tal y como se presentan en Logic and Theism [Sobel]) y la mayor parte de los argumentos deviene en formalmente válidos. Somos conscientes de que de esa manera hemos explicitado las premisas ocultas que validan el argumento pero a la vez disminuyen la solidez del mismo por tratarse de hipótesis de difícil justificación y con carga filosófica en muchos casos, incluso de falacias de petición de principio. Frecuentemente se trata de hipótesis existenciales, que claramente permiten pasar de una definición, que simplemente establece una correspondencia entre propiedades, a una asunción de consistencia, estableciendo que no son vacíos ciertos conjuntos. Se mencionan los temas relevantes a este estudio: el de la consideración de la existencia como un predicado, el de las descripciones impropias, el compromiso o aporte existencial de los enunciados universales, las categorías modales y el eventual colapso modal. Habría que destacar el esfuerzo de formalización para la que hemos empleado varias lógicas: clásica de primer, de orden superior (con descriptores como operadores lógicos) y lógica modal. Finalizamos señalando que el tema de los argumentos ontológicos sigue fascinando a los lógicos y filósofos, recibió mucha atención en el siglo XX y también en el XXI.Palabras clave: argumento ontológico, lógica de primer orden, lógica de orden superior, lógica modal, aporte existencial, colapso modal, descripciones impropiasAbstract:In this paper we propose a deep revision of the classical ontological arguments of Anselm, Descartes, Leibniz and Spinoza. The introduction clarifies the concept of ontological argument and point out the important logic distinction between the validity of an argument and its soundness, where besides validity it is required that all premises are actually true. The following sections discuss in turn the arguments of Anselm, Descartes, Spinoza and Leibniz. In all cases we have translated the relevant passages of the original argument and formalized its hypothesis and conclusion. In some cases we reconstructed the whole argument and added as hypothesis all statements that served the authors to prove their thesis. By doing this we detached ourselves from what is traditionally considered the argument (for example, as seen in Logic and Theism [Sobel]) and most of the arguments become formally valid.We are aware of the fact that in this way we made explicit the hidden assumptions that made the argument valid while weakening its strength. The reason why is that the new hypothesis are hard to justify as in many cases they have philosophical import and they even committed the fallacy known as petitio principii. Very often the new hypothesis are existential statements, which clearly allow passing from a definition, which simply establishes a correspondence between properties, to an assumption of consistency, stating that certain sets are not empty. The paper includes the issues relevant to this study: the consideration of existence as a predicate, improper descriptions, existential import of universal statements, modal categories and the eventual modal collapse. We should highlight the effort of formalization for which we have used several logics: classical first order logic, higher order (with a description operator) and modal logic. We conclude by pointing out that the subject of ontological arguments still fascinate logicians and philosophers and received attention in the twentieth and the twenty first century.Keywords: ontological argument, first order logic, higher-order logic, modal logic, existential import, modal collapse, improper description.</p

    Atomistic simulations of geopolymer models: the impact of disorder on structure and mechanics

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    Geopolymers are hydrated aluminosilicates with excellent binding properties. Geopolymers appeal to the construction sector as a more sustainable alternative to traditional cements, but their exploitation is limited by a poor understanding of the linkage between chemical composition and macroscopic properties. Molecular simulations can help clarify this linkage, but existing models based on amorphous or crystalline aluminosilicate structures provide only a partial explanation of experimental data on the nanoscale. This paper presents a new model for the molecular structure of geopolymers, in particular for nanoscale interfacial zones between crystalline and amorphous nanodomains, which are crucial for the overall mechanical properties of the material. For a range of Si–Al molar ratios and water contents, the proposed structures are analyzed in terms of skeletal density, ring structure, pore structure, bond-angle distribution, bond length distribution, X-ray diffraction, X-ray pair distribution function, elastic moduli, and large-strain mechanics. Results are compared with experimental data and with other simulation results for amorphous and crystalline molecular models, showing that the newly proposed structures better capture important structural features with an impact on mechanical properties. This offers a new starting point for the multiscale modeling of geopolymers

    Síndrome de «burnout» y apoyo social en maestros de Educación Primaria

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    This paper examines the relationship between burnout and perceived social support in a sample of 801 Primary School teachers. The Maslach Burnout Inventory (MBI) and the Duke-UNC-11 questionnaire were used. The statistical method used was canonical correspondence analysis, where the linear combination of the social support factors that maximises the dispersion of values of the three dimensions of the MBI was selected. The results of the study show that perceived social support relates to each of the dimensions of burnout syndrome in a different way and that is key to restore psychosocial balance.Este trabajo examina la relación entre burnout y apoyo social percibido en una muestra de 801 maestros de Educación Primaria. Para ello se usa el Maslach Burnout Inventory (MBI) y el cuestionario Duke-UNC-11. El método estadístico empleado fue el análisis canónico de correspondencias, donde se seleccionó la combinación lineal de los factores del apoyo social que maximiza la dispersión de valores de las tres dimensiones del MBI. Los resultados muestran que un 20,8% de los maestros sufre burnout. El apoyo social percibido, en su carácter restaurador del equilibrio psicosocial, se relaciona de distinto modo con las tres dimensiones del burnout.</em

    Entanglement in helium

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    Using a configuration-interaction variational method, we accurately compute the reduced, single-electron von Neumann entropy for several low-energy, singlet and triplet eigenstates of helium atom. We estimate the amount of electron-electron orbital entanglement for such eigenstates and show that it decays with energy.Comment: 5 pages, 2 figures, added references and discussio

    Cut-offs and response criteria for the Hospital Universitario la Princesa Index (HUPI) and their comparison to widely-used indices of disease activity in rheumatoid arthritis

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    Objective To estimate cut-off points and to establish response criteria for the Hospital Universitario La Princesa Index (HUPI) in patients with chronic polyarthritis. Methods Two cohorts, one of early arthritis (Princesa Early Arthritis Register Longitudinal PEARL] study) and other of long-term rheumatoid arthritis (Estudio de la Morbilidad y Expresión Clínica de la Artritis Reumatoide EMECAR]) including altogether 1200 patients were used to determine cut-off values for remission, and for low, moderate and high activity through receiver operating curve (ROC) analysis. The areas under ROC (AUC) were compared to those of validated indexes (SDAI, CDAI, DAS28). ROC analysis was also applied to establish minimal and relevant clinical improvement for HUPI. Results The best cut-off points for HUPI are 2, 5 and 9, classifying RA activity as remission if =2, low disease activity if >2 and =5), moderate if >5 and <9 and high if =9. HUPI''s AUC to discriminate between low-moderate activity was 0.909 and between moderate-high activity 0.887. DAS28''s AUCs were 0.887 and 0.846, respectively; both indices had higher accuracy than SDAI (AUCs: 0.832 and 0.756) and CDAI (AUCs: 0.789 and 0.728). HUPI discriminates remission better than DAS28-ESR in early arthritis, but similarly to SDAI. The HUPI cut-off for minimal clinical improvement was established at 2 and for relevant clinical improvement at 4. Response criteria were established based on these cut-off values. Conclusions The cut-offs proposed for HUPI perform adequately in patients with either early or long term arthritis

    The comparative responsiveness of Hospital Universitario Princesa Index and other composite indices for assessing rheumatoid arthritis activity

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    Objective To evaluate the responsiveness in terms of correlation of the Hospital Universitario La Princesa Index (HUPI) comparatively to the traditional composite indices used to assess disease activity in rheumatoid arthritis (RA), and to compare the performance of HUPI-based response criteria with that of the EULAR response criteria. Methods Secondary data analysis from the following studies: ACT-RAY (clinical trial), PROAR (early RA cohort) and EMECAR (pre-biologic era long term RA cohort). Responsiveness was evaluated by: 1) comparing change from baseline (Delta) of HUPI with Delta in other scores by calculating correlation coefficients; 2) calculating standardised effect sizes. The accuracy of response by HUPI and by EULAR criteria was analyzed using linear regressions in which the dependent variable was change in global assessment by physician (Delta GDA-Phy). Results Delta HUPI correlation with change in all other indices ranged from 0.387 to 0.791); HUPI's standardized effect size was larger than those from the other indices in each database used. In ACT-RAY, depending on visit, between 65 and 80% of patients were equally classified by HUPI and EULAR response criteria. However, HUPI criteria were slightly more stringent, with higher percentage of patients classified as non-responder, especially at early visits. HUPI response criteria showed a slightly higher accuracy than EULAR response criteria when using Delta GDA-Phy as gold standard. Conclusion HUPI shows good responsiveness in terms of correlation in each studied scenario (clinical trial, early RA cohort, and established RA cohort). Response criteria by HUPI seem more stringent than EULAR''s
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