13,990 research outputs found

    Redescription of Hemileius suramericanus (Acari, Oribatida, Scheloribatidae) with comments about Neotropical congeneric species

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    This paper represents the first redescription of Hemileius suramericanus (Hammer, 1958) (Oribatida, Scheloribatidae). Morphological and chaetotactic details are added to original Hammer's description. The species is compared with others Neotropical species of Hemileius and two new synonyms, H. laticlava and H. confundatus sensu Hammer, are proposed.Fil: Fredes, Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología; ArgentinaFil: Martínez, Pablo Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología; Argentin

    Fixed point theorems via Nash Equilibria

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    In this note we show that the fixed points of a continuous function (or of an upper semi-continuous correspondence, with non-empty and convex values) can be attained as Nash Equilibria of a game with finitely many players.

    A theoretical model of the endothelial cell morphology due to different waveforms

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    Endothelial cells are key units in the regulatory biological process of blood vessels. They represent an interface to transmit variations on the fluid dynamic changes. They are able to adapt its cytoskeleton, by means of microtubules reorientation and F-actin reorganization, due to new mechanical environments. Moreover, they are responsible for initiating a huge cascade of biological processes, such as the release of endothelins (ET-1), in charge of the constriction of the vessel and growth factors such as TGF-ß and PDGF. Although a huge efforts have been made in the experimental characterization and description of these two issues the computational modeling has not gained such an attention. In this work we study the 3D remodeling of endothelial cells based on the main features of blood flow. In particular we study how different oscillatory shear index and the time average wall shear stresses modify the endothelial cell shape. We found our model fitted the experimental works presented before in in vitro studies. We also include our model within a computational fluid dynamics simulation of a carotid artery to evaluate endothelial cell shape index which is a key predictor of atheroma plaque formation. Moreover, our approach can be coupled with models of collagen and smooth muscle cell growth, where remodeling and the associated release of chemical substance are involved.Peer ReviewedPostprint (author's final draft

    On the Utility of the Inverse Gamma Distribution in Modeling Composite Fading Channels

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    We introduce a general approach to characterize composite fading models based on inverse gamma (IG) shadowing. We first determine to what extent the IG distribution is an adequate choice for modeling shadow fading, by means of a comprehensive test with field measurements and other distributions conventionally used for this purpose. Then, we prove that the probability density function and cumulative density function of any IG-based composite fading model are directly expressed in terms of a Laplace-domain statistic of the underlying fast fading model, and in some relevant cases, as a mixture of well-known state-of-the-art distributions. We exemplify our approach by presenting a composite IG/two-wave with diffuse power fading model, for which its statistical characterization is directly attained in a simple form.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    General equilibrium existence with asset-backed securitization

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    We propose a specification of a general equilibrium model with securitization of collateral-backed promises and discuss the role of physical collateral to avoid, in equilibrium, pessimistic beliefs about the future rates of default. Promises are pooled in either pass-through securities or collateralized loans obligations (CLO), allowing the existence of different seniority lev- els among tranches in the same CLO. In case of default, borrowers may also suffer extra-economic penalties, which are internalized into a structure of non-ordered preferences. In this context, we prove the existence of an equilibrium in that investors are not over-pessimistic about the payments of derivatives. JEL Codes: D52, D91Asset Backed-Securitization, Extra-economic Default Penalties, Collateral, Non- ordered Preferences

    Quantum measurement optimization by decomposition of measurements into extremals

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    Using the convex structure of positive operator value measurements and of several quantities used in quantum metrology, such as quantum Fisher information or the quantum Van Trees information, we present an efficient numerical method to find the best strategy allowed by quantum mechanics to estimate a parameter. This method explores extremal measurements thus providing a significant advantage over previously used methods. We exemplify the method for different cost functions in a qubit and in a harmonic oscillator and find a strong numerical advantage when the desired target error is sufficiently small.Comment: 12 page
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