5,263 research outputs found

    Role of resonances in rho^0 -> pi^+ pi^- gamma

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    We study the effect of the sigma(600) and a_1(1260) resonances in the rho^0 -> pi^+ pi^- gamma decay, within the meson dominance model. Major effects are driven by the mass and width parameters of the sigma(600), and the usually neglected contribution of the a_1(1260), although small by itself, may become sizable through its interference with pion bremsstrahlung, and the proper relative sign can favor the central value of the experimental branching ratio. We present a procedure, using the gauge invariant structure of the resonant amplitudes, to kinematically enhance the resonant effects in the angular and energy distribution of the photon. We also elaborate on the coupling constants involved.Comment: 5 pages, 5 figures, accepted for publication in PR

    Holographic collisions in large DD effective theory

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    We study collisions of Gaussian mass-density blobs in a holographic plasma, using a large DD effective theory, as a model for holographic shockwave collisions. The simplicity of the effective theory allows us to perform the first 4+1 collisions in Einstein-Maxwell theory, which are dual to collisions of matter with non-zero baryonic number. We explore several collision scenarios with different blob shapes, impact parameters and charge values and find that collisions with impact parameter below the transverse width of the blobs are equivalent under rescaling. We also observe that charge weakly affects the rest of quantities. Finally, we study the entropy generated during collisions, both by charge diffusion and viscous dissipation. Multiple stages of linear entropy growth are identified, whose rates are not independent of the initial conditions.Comment: v3: Matches published versio

    Feeding of Sciaenid (Pisces: Sciaenidae) Larvae in Two Coastal Lagoons of the Gulf of Mexico

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    Stomach contents analyses showed that Leiostomus xanthurus (8.50-12.90 mm SL) had a wide trophic spectrum (15 food categories) with copepods and eggs of invertebrates as main components. In contrast, Micropogonias undulutus (6.65-12.20 mm SL) ingested only six food categories (copepods, eggs of invertebrates, crustacean nauplii, bamacle nauplii, amphipods and other crustaceans). There is an overlap of 73.2 to 83.0% in the diet of these two species. Bairdiella chrysoura (1.17-1.92 mm SL) fed primarily on juvenile pelecypods, crustacean nauplii, eggs of invertebrates, including gasteropods and copepods. Cynoscion nebulosus (1.50-2.42 mm SL) ingested juvenile pelecypods, copepods, crustacean nauplii, eggs of invertebrates and tintinnids, variability in overlap (47.4 to 79.5%) between these species was affected by size of the larvae

    IGF-1 Regulates the extracellular level of active MMP-2 and promotes Müller glial cell motility

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    In ischemic proliferative retinopathies, Müller glial cells (MGCs) acquire migratory abilities. However, the mechanisms that regulate this migration remain poorly understood. In addition, proliferative disorders associated with enhanced activities of matrix metalloproteinases (MMPs) also involve insulin-like growth factor (IGF)-1 participation. Therefore, the main interest of this work was to investigate the IGF-1 effect on the extracellular proteolytic activity in MGCs.Methods: Cell culture supernatants and cell lysates of the human MGC line MIO-M1 stimulated with IGF-1 were analyzed for MMP-2 by zymographic and Western blot analysis. The MGCs´ motility was evaluated by scratch wound assay. The MMP-2, β1-integrin, and focal adhesions were detected by confocal microscopy. The localization of active MMPs and actin cytoskeleton were evaluated by in situ zymography.Results: The IGF-1 induced the activation of canonical signaling pathways through the IGF-1R phosphorylation. Culture supernatants showed a relative decrease in the active form of MMP-2, correlating with an increased accumulation of MMP-2 protein in the MGCs´ lysate. The IGF-1 effect on MMP-2 was abolished by an IGF-1R blocking antibody, αIR3, as well as by the PI3-kinase inhibitor, LY294002. The IGF-1 increased the migratory capacity of MGCs, which was blocked by the GM6001 MMP inhibitor, LY294002 and αIR3. Finally, IGF-1 induced the intracellular distribution of MMP-2 toward cellular protrusions and the partial colocalization with β1-integrin and phospo-focal adhesion kinase signals. Gelatinase activity was concentrated along F-actin filaments.Conclusions: Taken together, these data indicate that IGF-1, through its receptor activation, regulates MGCs´ motility by a mechanism that involves the MMP-2 and PI3K signaling pathway.Fil: Lorenc, Valeria Erika. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; ArgentinaFil: Jaldín Fincati, Javier Roberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; ArgentinaFil: Luna Pinto, Jose Domingo. Departamento de Vítreo-retina, Centro Privado de Ojos R; ArgentinaFil: Chiabrando, Gustavo Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; ArgentinaFil: Sanchez, Maria Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; Argentin

    Nucleotomía Percutánea Automatizada: nuestra Experiencia

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    Ante las diferentes técnicas quirúrgicas en la patología del disco lumbar, los autores presentan su experiencia personal con la nucleotomía percutánea automatizada utilizando el nucleotomo de Surgical Dynamics. Sobre un total de 50 pacientes intervenidos se expone la técnica utilizada, con algunas variantes sobre la inicial de Onik, tal como la posición en sedestación del enfermo. Se puntualizan las indicaciones y contraindicaciones y se analizan los resultados obtenidos tras un mínimo de 6 meses de seguimiento. Se considera como una técnica útil, adecuada, relativamente inócua y que no sustituye sino que complementa a los procedimientos quirúrgicos convencionales.Faced with the different surgical techniques of lumbar disk pathology» the authors convery personal experience with automated percutaneous nucleotomy using the Surgical Dynamics. Based on the intervention of 50 patients, the technique used is explained, with some variations of the Onik procedure, such as the sitting position of the patient. The indications and contraindications are reviewed by the analysis. The results obtained with 6 months of follow up. The technique is considered usefull, proper, and relatively innocuous. It does not substitute but complements conventional surgical procedures

    Nulidad de los actos administrativos

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    72 p.La presente memoria tiene por objeto tratar la nulidad de los actos administrativos, atendiendo a la importancia que ésta tiene para el logro de un correcto funcionamiento de la Administración del Estado con la finalidad de garantizar a los particulares el respeto a sus derechos que pueden haber sido vulnerados con la dictación de algún acto administrativo ilegal. El método que se utilizará será el teórico y la jurisprudencia que se utilizará sólo servirá de apoyo. Tal nulidad se enfocará desde los dos ámbitos en que tiene aplicación, ya sea en sede judicial o administrativa. Se abordará el tema desde la perspectiva de la nulidad de derecho público y se tratará la Invalidación de los actos administrativos como la sanción aplicada por la propia Administración del Estado, consagrada en la Ley de Bases de los Procedimientos Administrativos

    Fighting the disagreement in Explainable Machine Learning with consensus

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    Machine learning (ML) models are often valued by the accuracy of their predictions. However, in some areas of science, the inner workings of models are as relevant as their accuracy. To understand how ML models work internally, the use of interpretability algorithms is the preferred option. Unfortunately, despite the diversity of algorithms available, they often disagree in explaining a model, leading to contradictory explanations. To cope with this issue, consensus functions can be applied once the models have been explained. Nevertheless, the problem is not completely solved because the final result will depend on the selected consensus function and other factors. In this paper, six consensus functions have been evaluated for the explanation of five ML models. The models were previously trained on four synthetic datasets whose internal rules were known in advance. The models were then explained with model-agnostic local and global interpretability algorithms. Finally, consensus was calculated with six different functions, including one developed by the authors. The results demonstrated that the proposed function is fairer than the others and provides more consistent and accurate explanations.Comment: 21 pages, 7 figure

    Eye drop Self-medication: Comparative Questionnaire-based study of two Latin American cities.

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    A broad spectrum of ocular symptoms are treated by self-medication with commercial eye-drops.  This behavior threatens individuals' visual health. In Latin America, evidence is poor. Objective:  To  detect,  characterize  and  compare  patterns  of  ophthalmic  self-medication  between  Córdoba (Argentina) and Barranquilla (Colombia).Design:  Analytic, cross-sectional and comparative population-based study. Setting: Two private tertiary care ophthalmology centers from Córdoba, Argentina, and Barranquilla, Colombia.Participants:  Patients 18 years of age or older who consulted for the first time in this two institutions duringAugust-November 2009, were included. A number of 570 patients were enrrolled.Methods:  Data collected through a semi-structured questionnaire. Main outcome measure: To determine thefrequency of self-medication with eyedrops on a specific population of two cities in Latin America.Results:  Comparable  rates  of  ocular  self-medication  were  found  (25.6%  and  25.7%  for  Cordoba  and Barranquilla, respectively). The percentage of men and women who self-medicated was not significantly different between both samples. The major source of eye drops recommendation in the Argentineans patients was the pharmacist (31%); while the social source was predominant in Colombian individuals (53%). In Cordoba, the most frequently used product was a non-steroidal anti-inflammatory drop in combination with a vasoconstrictive agent (32%); while in Barranquilla, antibiotic eye drops were preferred (33%). Self-medication was higher between the ages of 31 and 50 years old in Argentinean citizens (28%) and between 18 to 31 years old in the Colombiancommunity (39%). This habit was found mostly in patients who completed university studies in Cordoba (33%); in Barranquilla, individuals with lower educational level practice more this behavior (36%).Conclusion:  In both populations, patients commonly treat ocular conditions by self-medicating. Currently, anincreasing number of eye drops are obtainable without prescription and a high percentage of self-medicated patients in both samples ignore the possible side effects of the used medication.Fil: Marquez, Gabriel. Fundación VER; ArgentinaFil: Hildegard Piñeros-Heilbron. Fundación Oftalmológica del Caribe; ColombiaFil: Sanchez, Victoria M.. Fundación VER; ArgentinaFil: Torres, Victor Eduardo Roque. Fundación VER; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones y Estudios sobre Cultura y Sociedad. Universidad Nacional de Córdoba. Centro de Investigaciones y Estudios sobre Cultura y Sociedad; ArgentinaFil: Gramajo, Ana L.. Fundación VER; ArgentinaFil: Juarez, Claudio P.. Fundación VER; Argentina. Fundación Oftalmológica del Caribe; ColombiaFil: Peña, Fernando. Fundación Oftalmológica del Caribe; ColombiaFil: Luna, José D.. Fundación VER; Argentin
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