2,413 research outputs found

    Diagrammatic logic applied to a parameterization process

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    This paper provides an abstract definition of some kinds of logics, called diagrammatic logics, together with a definition of morphisms and of 2-morphisms between diagrammatic logics. The definition of the 2-category of diagrammatic logics rely on category theory, mainly on adjunction, categories of fractions and limit sketches. This framework is applied to the formalization of a parameterization process. This process, which consists in adding a formal parameter to some operations in a given specification, is presented as a morphism of logics. Then the parameter passing process, for recovering a model of the given specification from a model of the parameterized specification and an actual parameter, is seen as a 2-morphism of logics

    Simulated seed predation reveals a variety of germination responses of neotropical rain forest species

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    Seed predation, an omnipresent phenomenon in tropical rain forests, is an important determinant of plant recruitment and forest regeneration. Although seed predation destroys large amounts of the seed crop of numerous tropical species, in many cases individual seed damage is only partial. The extent to which partial seed predation affects the recruitment of new individuals in the population depends on the type and magnitude of alteration of the germination behavior of the damaged seeds. We analyzed the germination dynamics of 11 tropical woody species subject to increasing levels of simulated seed predation (0–10% seed mass removal). Germination response to seed damage varied considerably among species but could be grouped into four distinct types: (1) complete inability to germinate under damage ≥1%, (2) no effect on germination dynamics, (3) reduced germination with increasing damage, and (4) reduced final germination but faster germination with increasing damage. We conclude that partial seed predation is often nonlethal and argue that different responses to predation may represent different proximal mechanisms for coping with partial damage, with potential to shape, in the long run, morphological and physiological adaptations in tropical, large-seeded species

    Quantifying image distortion based on Gabor filter bank and multiple regression analysis

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    Image quality assessment is indispensable for image-based applications. The approaches towards image quality assessment fall into two main categories: subjective and objective methods. Subjective assessment has been widely used. However, careful subjective assessments are experimentally difficult and lengthy, and the results obtained may vary depending on the test conditions. On the other hand, objective image quality assessment would not only alleviate the difficulties described above but would also help to expand the application field. Therefore, several works have been developed for quantifying the distortion presented on a image achieving goodness of fit between subjective and objective scores up to 92%. Nevertheless, current methodologies are designed assuming that the nature of the distortion is known. Generally, this is a limiting assumption for practical applications, since in a majority of cases the distortions in the image are unknown. Therefore, we believe that the current methods of image quality assessment should be adapted in order to identify and quantify the distortion of images at the same time. That combination can improve processes such as enhancement, restoration, compression, transmission, among others. We present an approach based on the power of the experimental design and the joint localization of the Gabor filters for studying the influence of the spatial/frequencies on image quality assessment. Therefore, we achieve a correct identification and quantification of the distortion affecting images. This method provides accurate scores and differentiability between distortions

    Relación entre periodontitis crónica y la obesidad en pacientes atendidos en una clínica estomatológica

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    El objetivo de la presente investigacion fue determinar la relacion entre periodontitis cronica y la obesidad en pacientes atendidos en la Clinica de la Facultad de Estomatologia de la Universidad Inca Garcilaso de la Vega en el ano 2017.The objective of the present investigation was to determine the relationship between chronic periodontitis and obesity in patients treated at the Clinic of the Faculty of Stomatology of the Inca Garcilaso de la Vega University in 201

    Individual variance in the attributes of Clusia salvinii Donn. Smith associated with the attraction of frugivores in the dispersal of fruits and seeds

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    Seed dispersal is one of the processes of plant-frugivore interactions that involves characteristics specific to the plant effecting the attraction of frugivores. In this paper, the individual variance in the attributes of Clusia salvinii in relation to the attraction of frugivores and its effect on the dispersal of fruits and seeds in the Reserva de Nanchititla, State of Mexico was studied. The morphometric characteristics of 25 trees of the C. salvinii species were evaluated (height, coverage, number of fruit, number of seeds per fruit, and fruit below the canopy). The removal of fruits and seeds (dispersal) was also estimated, as well as some of its attributes as estimators of the quantity of biomass assigned to the reproduction or as compensation for the dispersers (average weight per tree, average weight of the arils per tree). According to the results, tree height and harvest size or fruit production have an effect on the removal of seeds. On the other hand, the mass of the fruit, aril and seed had no relation to the removal of the fruit. Tree height and the quantity of fruit play an important role in the attraction of dispersers

    Successful development of vitrified embryonic kidney after laparoscopy transplantation into non-immunosuppressed hosts

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    [EN] Transplantation from living or deceased donors has been limited by donor availability that is opposed to the increasing demand and by the risk of allograft loss rejection and immunosuppressive therapy toxicity. In recent years, xenotransplantation of metanephroi has offered a novel solution for the unlimited supply of human donor organs. However, even if in a most favourable and idyllic situation the organ availability and its demand could be balanced using transplantation of animal embryonic organs, the future of this treatment would still be compromised without proper long-term storage procedure. Thus, based on the ongoing long-term storage necessities, this study was designed to investigate the effect of two specific time window of the metanephroi development (15 days-old and 16 days-old) on the in vivo developmental capacity and the developed morphologically normal glomeruli of vitrified metanephroi in non-immunosuppressive rabbits. Metanephroi originating from 15 and 16 days old rabbit embryos were vitrified using M22 solution and Cryotop® as a device. After three months of storage in liquid nitrogen, metanephroi were transplanted into non-immunosuppressed adult hosts by laparoscopy surgery. Twenty-one days after allotransplantation, 6 (32%) and 7 (35%) new kidneys were recovered. All the new kidneys recovered exhibited significant growth and mature glomeruli. However, histomorphometry analysis revealed that new kidneys developed from 16 days-old metanephroi exhibit a greater degree of maturity compared with 15 days-old metanephroi. Results obtained in the present study point out that, in rabbit model, vitrified 16 days-old metanephroi could be stored in liquid nitrogen, achieving good in vivo developmental capacity and the developed morphologically normal glomeruli after laparoscopy transplantation into non-immunosuppressed hosts.This work was supported by funds from the Generalitat Valenciana Research Programme (PrometeoII 2014/036), ALCER-TURIA foundation and PRECIPITA CROWDFUNDING. English text version was revised by N. Macowan English Language Service.Garcia-Dominguez, X.; Vicente Antón, JS.; Vera Donoso, CD.; Marco-Jiménez, F. (2017). Successful development of vitrified embryonic kidney after laparoscopy transplantation into non-immunosuppressed hosts. Transplantation open. 2(2):1-5. https://doi.org/10.15761/JTO.1000125S152

    Hybrid dome with total internal reflector as a secondary optical element for CPV

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    Secondary optical elements (SOEs) are used in Concentrator Photovoltaic (CPV) modules to allow the concentration ratio to exceed those typically achievable by Fresnel lenses, reducing cell costs, without sacrificing tolerance to tracking errors. One option is a “dome” SOE: a simple, single surface refractive optic that images the primary lens onto the cell while immersing it. In this article, we explore the limits of this type of SOE and propose an evolved version, which we dub the Hybrid Dome Reflector (HDR), which offers advantages especially for high concentration modules with large cells, where reflective secondaries do not offer sufficient acceptance angle, but other dielectric secondaries, such as the Dielectric Totally Internally Reflecting Concentrator DTIRC, may be too large for economical manufacture. We discuss aspects of HDR design and share selected ray-tracing simulations and experimental results. We show that the new HDR design improves acceptance angle and tolerances to manufacturing error and lens temperature as compared to a reflective SOE built while offering similar efficiencies

    Metallic diluted dimerization in VO2 tweeds

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    Altres ajuts: ICN2 was also supported by the CERCA programme (Generalitat de Catalunya).The observation of electronic phase separation textures in vanadium dioxide, a prototypical electron-correlated oxide, has recently added new perspectives on the long standing debate about its metal-insulator transition and its applications. Yet, the lack of atomically resolved information on phases accompanying such complex patterns still hinders a comprehensive understanding of the transition and its implementation in practical devices. In this work, atomic resolution imaging and spectroscopy unveils the existence of ferroelastic tweed structures on ≈5 nm length scales, well below the resolution limit of currently used spectroscopic imaging techniques. Moreover, density functional theory calculations show that this pretransitional fine-scale tweed, which on average looks and behaves like the standard metallic rutile phase, is in fact weaved by semi-dimerized chains of vanadium in a new monoclinic phase that represents a structural bridge to the monoclinic insulating ground state. These observations provide a multiscale perspective for the interpretation of existing data, whereby phase coexistence and structural intermixing can occur all the way down to the atomic scale
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