168 research outputs found
On the local existence of maximal slicings in spherically symmetric spacetimes
In this talk we show that any spherically symmetric spacetime admits locally
a maximal spacelike slicing. The above condition is reduced to solve a
decoupled system of first order quasi-linear partial differential equations.
The solution may be accomplished analytical or numerically. We provide a
general procedure to construct such maximal slicings.Comment: 4 pages. Accepted for publication in Journal of Physics: Conference
Series, Proceedings of the Spanish Relativity Meeting ERE200
Quantitative analysis of the dripping and jetting regimes in co-flowing capillary jets
We study a liquid jet that breaks up into drops in an external co-flowing
liquid inside a confining microfluidic geometry. The jet breakup can occur
right after the nozzle in a phenomenon named dripping or through the generation
of a liquid jet that breaks up a long distance from the nozzle, which is called
jetting. Traditionally, these two regimes have been considered to reflect the
existence of two kinds of spatiotemporal instabilities of a fluid jet, the
dripping regime corresponding to an absolutely unstable jet and the jetting
regime to a convectively unstable jet. Here, we present quantitative
measurements of the dripping and jetting regimes, both in an unforced and a
forced state, and compare these measurements with recent theoretical studies of
spatiotemporal instability of a confined liquid jet in a co-flowing liquid. In
the unforced state, the frequency of oscillation and breakup of the liquid jet
is measured and compared to the theoretical predictions. The dominant frequency
of the jet oscillations as a function of the inner flow rate agrees
qualitatively with the theoretical predictions in the jetting regime but not in
the dripping regime. In the forced state, achieved with periodic laser heating,
the dripping regime is found to be insensitive to the perturbation and the
frequency of drop formation remains unaltered. The jetting regime, on the
contrary, amplifies the externally imposed frequency, which translates in the
formation of drops at the frequency imposed by the external forcing. In
conclusion, the dripping and jetting regimes are found to exhibit the main
features of absolutely and convectively unstable flows respectively, but the
frequency selection in the dripping regime is not ruled by the absolute
frequency predicted by the stability analysis.Comment: 10 pages, 12 figures, to appear in Physics of Fluid
Perceived health and its relation with macrosocial and individual factors in children from two departments of Tucumán, Argentina
Introducción: El estudio de la calidad de vida relacionada con la salud (CVRS) durante la infancia permite identificar factores que condicionan el crecimiento y el desarrollo. Los objetivos de este trabajo fueron: a) describir la CVRS de niños con edades comprendidas entre 8,0 y 11,9 años que residían en la provincia de Tucumán; y b) analizar si la CVRS variaba en relación con factores macrosociales (calidad de vida departamental, residencia urbano-rural, nivel socioeconómico) e individuales (edad y sexo).
Población y métodos: Estudio cuantitativo, transversal en escolares de los departamentos de Yerba Buena y Simoca. Se aplicó el cuestionario KIDSCREEN-52 para medir dimensiones de CVRS y las pruebas t de Student, análisis de la varianza y regresión logística multivariada para el análisis según factores macrosociales e individuales.
Resultados: Se analizaron 1647 encuestas. Los escolares de menor edad y los varones, en general, tuvieron una mejor percepción de su salud. Los residentes en Yerba Buena presentaron puntuaciones medias significativamente más bajas en la dimensión recursos económicos, comparados con los de Simoca (45,3 vs. 46,7, p: 0,01). No hubo asociación entre el nivel socioeconómico y la CVRS. Los niños rurales puntuaron más bajo en la mayoría de las dimensiones, con diferencias significativas en autopercepción (51,3 vs. 53,0, p: 0,01) y estado de ánimo (43,2 vs. 44,5, p: 0,03).
Conclusiones: La salud percibida de los niños de Yerba Buena y Simoca varió en relación a aspectos macrosociales e individuales. En Yerba Buena, la percepción de los recursos económicos fue peor respecto de Simoca. En general, las apreciaciones de los niños urbanos fueron más favorables que las de los rurales. Los varones y los escolares de menor edad percibieron mejor su salud.Facultad de Ciencias VeterinariasInstituto de Genética Veterinari
Perceived health and its relation with macrosocial and individual factors in children from two departments of Tucumán, Argentina
Introducción: El estudio de la calidad de vida relacionada con la salud (CVRS) durante la infancia permite identificar factores que condicionan el crecimiento y el desarrollo. Los objetivos de este trabajo fueron: a) describir la CVRS de niños con edades comprendidas entre 8,0 y 11,9 años que residían en la provincia de Tucumán; y b) analizar si la CVRS variaba en relación con factores macrosociales (calidad de vida departamental, residencia urbano-rural, nivel socioeconómico) e individuales (edad y sexo).
Población y métodos: Estudio cuantitativo, transversal en escolares de los departamentos de Yerba Buena y Simoca. Se aplicó el cuestionario KIDSCREEN-52 para medir dimensiones de CVRS y las pruebas t de Student, análisis de la varianza y regresión logística multivariada para el análisis según factores macrosociales e individuales.
Resultados: Se analizaron 1647 encuestas. Los escolares de menor edad y los varones, en general, tuvieron una mejor percepción de su salud. Los residentes en Yerba Buena presentaron puntuaciones medias significativamente más bajas en la dimensión recursos económicos, comparados con los de Simoca (45,3 vs. 46,7, p: 0,01). No hubo asociación entre el nivel socioeconómico y la CVRS. Los niños rurales puntuaron más bajo en la mayoría de las dimensiones, con diferencias significativas en autopercepción (51,3 vs. 53,0, p: 0,01) y estado de ánimo (43,2 vs. 44,5, p: 0,03).
Conclusiones: La salud percibida de los niños de Yerba Buena y Simoca varió en relación a aspectos macrosociales e individuales. En Yerba Buena, la percepción de los recursos económicos fue peor respecto de Simoca. En general, las apreciaciones de los niños urbanos fueron más favorables que las de los rurales. Los varones y los escolares de menor edad percibieron mejor su salud.Facultad de Ciencias VeterinariasInstituto de Genética Veterinari
Perceived health and its relation with macrosocial and individual factors in children from two departments of Tucumán, Argentina
Introducción: El estudio de la calidad de vida relacionada con la salud (CVRS) durante la infancia permite identificar factores que condicionan el crecimiento y el desarrollo. Los objetivos de este trabajo fueron: a) describir la CVRS de niños con edades comprendidas entre 8,0 y 11,9 años que residían en la provincia de Tucumán; y b) analizar si la CVRS variaba en relación con factores macrosociales (calidad de vida departamental, residencia urbano-rural, nivel socioeconómico) e individuales (edad y sexo).
Población y métodos: Estudio cuantitativo, transversal en escolares de los departamentos de Yerba Buena y Simoca. Se aplicó el cuestionario KIDSCREEN-52 para medir dimensiones de CVRS y las pruebas t de Student, análisis de la varianza y regresión logística multivariada para el análisis según factores macrosociales e individuales.
Resultados: Se analizaron 1647 encuestas. Los escolares de menor edad y los varones, en general, tuvieron una mejor percepción de su salud. Los residentes en Yerba Buena presentaron puntuaciones medias significativamente más bajas en la dimensión recursos económicos, comparados con los de Simoca (45,3 vs. 46,7, p: 0,01). No hubo asociación entre el nivel socioeconómico y la CVRS. Los niños rurales puntuaron más bajo en la mayoría de las dimensiones, con diferencias significativas en autopercepción (51,3 vs. 53,0, p: 0,01) y estado de ánimo (43,2 vs. 44,5, p: 0,03).
Conclusiones: La salud percibida de los niños de Yerba Buena y Simoca varió en relación a aspectos macrosociales e individuales. En Yerba Buena, la percepción de los recursos económicos fue peor respecto de Simoca. En general, las apreciaciones de los niños urbanos fueron más favorables que las de los rurales. Los varones y los escolares de menor edad percibieron mejor su salud.Facultad de Ciencias VeterinariasInstituto de Genética Veterinari
A diet rich in saturated fat and cholesterol aggravates the effect of bacterial lipopolysaccharide on alveolar bone loss in a rabbit model of periodontal disease
Increasing evidence connects periodontitis with a variety of systemic diseases, including metabolic syndrome, atherosclerosis, and non-alcoholic fatty liver disease (NAFLD). The proposal of this study was to evaluate the role of diets rich in saturated fat and cholesterol in some aspects of periodontal diseases in a lipopolysaccharide (LPS)-induced model of periodontal disease in rabbits and to assess the influence of a periodontal intervention on hyperlipidemia, atherosclerosis, and NAFLD progression to non-alcoholic steatohepatitis. Male rabbits were maintained on a commercial standard diet or a diet rich in saturated fat (3% lard w/w) and cholesterol (1.3% w/w) (HFD) for 40 days. Half of the rabbits on each diet were treated 2 days per week with intragingival injections of LPS from Porphyromonas gingivalis. Morphometric analyses revealed that LPS induced higher alveolar bone loss (ABL) around the first premolar in animals receiving standard diets, which was exacerbated by the HFD diet. A higher score of acinar inflammation in the liver and higher blood levels of triglycerides and phospholipids were found in HFD-fed rabbits receiving LPS. These results suggest that certain dietary habits can exacerbate some aspects of periodontitis and that bad periodontal health can contribute to dyslipidemia and promote NAFLD progression, but only under certain conditions
A Diet Rich in Saturated Fat and Cholesterol Aggravates the Effect of Bacterial Lipopolysaccharide on Alveolar Bone Loss in a Rabbit Model of Periodontal Disease
Increasing evidence connects periodontitis with a variety of systemic diseases, including metabolic syndrome, atherosclerosis, and non-alcoholic fatty liver disease (NAFLD). The proposal of this study was to evaluate the role of diets rich in saturated fat and cholesterol in some aspects of periodontal diseases in a lipopolysaccharide (LPS)-induced model of periodontal disease in rabbits and to assess the influence of a periodontal intervention on hyperlipidemia, atherosclerosis, and NAFLD progression to non-alcoholic steatohepatitis. Male rabbits were maintained on a commercial standard diet or a diet rich in saturated fat (3% lard w/w) and cholesterol (1.3% w/w) (HFD) for 40 days. Half of the rabbits on each diet were treated 2 days per week with intragingival injections of LPS from Porphyromonas gingivalis. Morphometric analyses revealed that LPS induced higher alveolar bone loss (ABL) around the first premolar in animals receiving standard diets, which was exacerbated by the HFD diet. A higher score of acinar inflammation in the liver and higher blood levels of triglycerides and phospholipids were found in HFD-fed rabbits receiving LPS. These results suggest that certain dietary habits can exacerbate some aspects of periodontitis and that bad periodontal health can contribute to dyslipidemia and promote NAFLD progression, but only under certain conditions
A Configurable Event-Driven Convolutional Node with Rate Saturation Mechanism for Modular ConvNet Systems Implementation
Convolutional Neural Networks (ConvNets) are a particular type of neural network often used for many applications like image recognition, video analysis or natural language processing. They are inspired by the human brain, following a specific organization of the connectivity pattern between layers of neurons known as receptive field. These networks have been traditionally implemented in software, but they are becoming more computationally expensive as they scale up, having limitations for real-time processing of high-speed stimuli. On the other hand, hardware implementations show difficulties to be used for different applications, due to their reduced flexibility. In this paper, we propose a fully configurable event-driven convolutional node with rate saturation mechanism that can be used to implement arbitrary ConvNets on FPGAs. This node includes a convolutional processing unit and a routing element which allows to build large 2D arrays where any multilayer structure can be implemented. The rate saturation mechanism emulates the refractory behavior in biological neurons, guaranteeing a minimum separation in time between consecutive events. A 4-layer ConvNet with 22 convolutional nodes trained for poker card symbol recognition has been implemented in a Spartan6 FPGA. This network has been tested with a stimulus where 40 poker cards were observed by a Dynamic Vision Sensor (DVS) in 1 s time. Different slow-down factors were applied to characterize the behavior of the system for high speed processing. For slow stimulus play-back, a 96% recognition rate is obtained with a power consumption of 0.85mW. At maximum play-back speed, a traffic control mechanism downsamples the input stimulus, obtaining a recognition rate above 63% when less than 20% of the input events are processed, demonstrating the robustness of the networkEuropean Union 644096, 687299Gobierno de España TEC2016-77785- P, TEC2015-63884-C2-1-PJunta de Andalucía TIC-6091, TICP120
Gravitational waves in dynamical spacetimes with matter content in the Fully Constrained Formulation
The Fully Constrained Formulation (FCF) of General Relativity is a novel
framework introduced as an alternative to the hyperbolic formulations
traditionally used in numerical relativity. The FCF equations form a hybrid
elliptic-hyperbolic system of equations including explicitly the constraints.
We present an implicit-explicit numerical algorithm to solve the hyperbolic
part, whereas the elliptic sector shares the form and properties with the well
known Conformally Flat Condition (CFC) approximation. We show the stability
andconvergence properties of the numerical scheme with numerical simulations of
vacuum solutions. We have performed the first numerical evolutions of the
coupled system of hydrodynamics and Einstein equations within FCF. As a proof
of principle of the viability of the formalism, we present 2D axisymmetric
simulations of an oscillating neutron star. In order to simplify the analysis
we have neglected the back-reaction of the gravitational waves into the
dynamics, which is small (<2 %) for the system considered in this work. We use
spherical coordinates grids which are well adapted for simulations of stars and
allow for extended grids that marginally reach the wave zone. We have extracted
the gravitational wave signature and compared to the Newtonian quadrupole and
hexadecapole formulae. Both extraction methods show agreement within the
numerical errors and the approximations used (~30 %).Comment: 17 pages, 9 figures, 2 tables, accepted for publication in PR
Role of AMPK in the protective effects exerted by triiodothyronine in ischemic-reperfused myocardium
Recent studies have provided evidence that triiodothyronine (T3) might play an effective role in the recovery of ischemic myocardium, through the preservation of mitochondrial function and the improvement of energy substrate metabolism. To this respect, it has been suggested that T3 could activate AMP-activated protein kinase (AMPK), the cellular ‘fuel-gauge’ enzyme, although its role has yet to be elucidated. The aim of the present study was to investigate the effects produced by acute treatment with T3 (60 nM) and the pharmacological inhibition of AMPK by compound C on isolated rat left atria subjected to 75 min simulated ischemia-75 min reperfusion. Results showed that T3 increased AMPK activation during simulated ischemia-reperfusion, while compound C prevented it. At the end of simulated reperfusion, acute T3 treatment increased contractile function recovery and cellular viability conservation. Mitochondrial ultrastructure was better preserved in the presence of T3 as well as mitochondrial ATP production rate and tissue ATP content. Calcium retention capacity, a parameter widely used as an indicator of the resistance of mitochondrial permeability transition pore (MPTP) to opening, and GSK-3β phosphorylation, a master switch enzyme that limits MPTP opening, were increased by T3 administration. All these beneficial effects exerted by T3 acute treatment were prevented when compound C was co-administrated. The present study provided original evidence that T3 enhances intrinsic activation of AMPK during myocardial ischemiareperfusion, being this enzyme involved, at least in part, in the protective effects exerted by T3, contributing to mitochondrial structure and function preservation, post-ischemic contractile recovery and conservation of cellular viability.Fil: Hermann, Romina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Metabolismo del Fármaco. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Metabolismo del Fármaco; ArgentinaFil: Mestre Cordero, Victoria Evangelina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Metabolismo del Fármaco. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Metabolismo del Fármaco; ArgentinaFil: Fernández Pazos, María de Las Mercedes. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Ciencias Biológicas. Cátedra de Fisiología Humana; ArgentinaFil: Córdoba, Mailen Florencia. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Ciencias Biológicas. Cátedra de Fisiología Humana; ArgentinaFil: Reznik, Federico Joaquín. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Ciencias Biológicas. Cátedra de Fisiología Humana; ArgentinaFil: Vélez, Débora Elisabet. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Metabolismo del Fármaco. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Metabolismo del Fármaco; ArgentinaFil: Fellet, Andrea L.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Metabolismo del Fármaco. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Metabolismo del Fármaco; ArgentinaFil: Marina Prendes, María Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Metabolismo del Fármaco. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Metabolismo del Fármaco; Argentin
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