107 research outputs found

    Evolución y terrorismo suicida: las raíces biológicas del altruismo letal [Ressenya]

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    Reseña del libro de Adolf Tobeña "Mártires mortíferos. Un itinerario por el cerebro de los suicidas atacantes" Valencia, PUV-Cátedra Divulgació de la Ciencia, 2005, 274 p

    Manifestações neurológicas como forma de apresentação do cancro do pulmão

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    O cancro do pulmão, em particular o carcinoma de pequenas células do pulmão, é a principal causa maligna de síndromes paraneoplásicas. Esta revisão foca-se nos dados da literatura acerca da associação das síndromes paraneoplásicas com o cancro do pulmão. As síndromes paraneoplásicas podem ser o primeiro sinal de apresentação ou de recorrência da neoplasia subjacente. Geralmente, a síndrome paraneoplásica pode ser aliviada com o tratamento bem sucedido do tumor. Síndromes paraneoplásicas, em particular as neurológicas, são doenças com fisiopatologia relacionada ao cancro, mas não atribuíveis a metástases ou outros mecanismos indirectos. Desenvolvem-se em menos de 1% dos doentes com neoplasias sistémicas, mais frequentemente neoplasia pulmonar de pequenas células, neoplasias da mama e ovário. Podem afectar qualquer nível do sistema nervoso e frequentemente antecedem a detecção do tumor. O diagnóstico correcto depende de um alto grau de suspeição por parte do médico, além do conhecimento de suas manifestações clínicas e dos tumores tipicamente a elas associadas. Por anteceder o diagnóstico da neoplasia, a sua importância reside na oportunidade de identificar e tratar precocemente o tumor, que muitas vezes é pequeno e por isso mesmo escapa à detecção mesmo após avaliações clínicas repetidas

    La medicina darwinista: el origen evolutivo de la enfermedad

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    La influencia del darwinismo ha marcado el desarrollo de toda la biología moderna. Sorprendentemente, la medicina se ha mantenido, en buena medida, al margen del pensamiento evolutivo hasta hace unos años. La situación experimentó un cambio drástico en el año 1991 cuando el psiquiatra Randolph M. Nesse de la Universidad de Michigan y el prestigioso evolucionista George C. Williams de la Universidad de Nueva York publicaron un artículo titulado “El amanecer de la medicina darwinista

    Castrodeza. 2009. La darwinización del mundo

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    On solving large-scale multistage stochastic optimization problems with a new specialized interior-point approach

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    © 2023 The Authors. Published by Elsevier B.VA novel approach based on a specialized interior-point method (IPM) is presented for solving largescale stochastic multistage continuous optimization problems, which represent the uncertainty in strategic multistage and operational two-stage scenario trees. This new solution approach considers a splitvariable formulation of the strategic and operational structures. The specialized IPM solves the normal equations by combining Cholesky factorizations with preconditioned conjugate gradients, doing so for, respectively, the constraints of the stochastic formulation and those that equate the split-variables. We show that, for multistage stochastic problems, the preconditioner (i) is a block-diagonal matrix composed of as many shifted tridiagonal matrices as the number of nested strategic-operational two-stage trees, thus allowing the efficient solution of systems of equations; (ii) its complexity in a multistage stochastic problem is equivalent to that of a very large-scale two-stage problem. A broad computational experience is reported for large multistage stochastic supply network design (SND) and revenue management (RM) problems. Some of the most difficult instances of SND had 5 stages, 839 million linear variables, 13 million quadratic variables, 21 million constraints, and 3750 scenario tree nodes; while those of RM had 8 stages, 278 million linear variables, 100 million constraints, and 100,000 scenario tree nodes. For those problems, the proposed approach obtained the solution in 1.1 days using 174 gigabytes of memory for SND, and in 1.7 days using 83 gigabytes for RM; while CPLEX v20.1 required more than 53 days and 531 gigabytes for SND, and more than 19 days and 410 gigabytes for RM.J. Castro was supported by the MCIN/AEI/FEDER grant RTI2018-097580-B-I00. L.E. Escudero was supported by the MCIN/AEI/10.13039/501100011033 grant PID2021-122640OB-I00. J.F. Monge was supported by the MCIN/AEI/10.13039/501100011033/ERDF grants PID2019-105952GB-I00 and PID2021-122344NB-I00, and by PROMETEO/2021/063 grant funded by the government of the Valencia Community, Spain.Peer ReviewedPostprint (published version

    On solving large-scale multistage stochastic problems with a new specialized interior-point approach

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    A novel approach based on a specialized interior-point method (IPM) is presented for solving large-scale stochastic multistage continuous optimization problems, which represent the uncertainty in strategic multistage and operational two-stage scenario trees, the latter being rooted at the strategic nodes. This new solution approach considers a split-variable formulation of the strategic and operational structures, for which copies are made of the strategic nodes and the structures are rooted in the form of nested strategic-operational two-stage trees. The specialized IPM solves the normal equations of the problem’s Newton system by combining Cholesky factorizations with preconditioned conjugate gradients, doing so for, respectively, the constraints of the stochastic formulation and those that equate the split-variables. We show that, for multistage stochastic problems, the preconditioner (i) is a block-diagonal matrix composed of as many shifted tridiagonal matrices as the number of nested strategicoperational two-stage trees, thus allowing the efficient solution of systems of equations; (ii) its complexity in a multistage stochastic problem is equivalent to that of a very large-scale two-stage problem. A broad computational experience is reported for large multistage stochastic supply network design (SND) and revenue management (RM) problems; the mathematical structures vary greatly for those two application types. Some of the most difficult instances of SND had 5 stages, 839 million variables, 13 million quadratic variables, 21 million constraints, and 3750 scenario tree nodes; while those of RM had 8 stages, 278 million variables, 100 million constraints, and 100,000 scenario tree nodes. For those problems, the proposed approach obtained the solution in 2.3 days using 167 gigabytes of memory for SND, and in 1.7 days using 83 gigabytes for RM; while the state-of-the-art solver CPLEX v20.1 required more than 24 days and 526 gigabytes for SND, and more than 19 days and 410 gigabytes for RMPeer ReviewedPreprin

    Evolución y cultura: una aproximación naturalista a las ciencias sociales

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    Las tradiciones que configuran el cuerpo central de teoría en las ciencias sociales comparten la convicción de que las culturas constituyen sistemas que pueden ser interpretados sin tener en cuenta las características psicobiológicas de la naturaleza humana. Frente a esto, desde hace unos años, distintas aproximaciones naturalistas, como la psicología evolucionista y la teoría de la herencia dual, han logrado construir modelos bastante sólidos en el análisis de la cultura. Aquí se revisan brevemente los elementos básicos de esos modelos y, en la parte final del artículo, se presenta una propuesta alternativa basada en lo que denominamos el aprendizaje social asesor

    Cultura, adaptación y ciencias sociales: una aproximación naturalista

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    RESUMENEn la primera parte de este artículo defendemos que la evolución de la cultura en nuestra especie es consecuencia de una naturaleza humana esencialmente valorativa, la naturaleza de Homo suadens. La propuesta considera que nuestros antepasados homínidos dotados de la capacidad de aprobar y reprobar la conducta ajena desarrollaron un sistema de transmisión cultural assessor entre padres e hijos, el cual transformó el aprendizaje social en un sistema de herencia acumulativo. En la segunda parte, defendemos, desde nuestra condición de Homo suadens, la necesidad de reconceptualizar algunos de los problemas presentes en el núcleo teórico de las ciencias sociales.PALABRAS CLAVEAPRENDIZAJE SOCIAL, EVOLUCIÓN CULTURAL, TRANSMISIÓN ASSESSOR, HOMO SUADENSABSTRACTIn this paper, first we argue that the evolution of culture in our species is the result of an essentially evaluative human nature, the nature of Homo suadens. The proposal considers that our hominid ancestors endowed with the ability to approve or disapprove of the conduct of others developed a system of assessor cultural transmission between parents and children, who transformed social learning into a cumulative inheritance system. Second, we defend, from our Homo suadens condition, the need to reconceptualise some of the problems lying at the theoretical core of social sciences.KEY WORDSSOCIAL LEARNING, CULTURAL EVOLUTION, ASSESSOR TRANSMISSION, HOMO SUADEN

    Syphilis Hereditaria

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