2,668 research outputs found

    Reiteraciones: ritmo y diseminación en Génesis 1,1-2,4a

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     PRELIMINARES. I. LA SECCIÓN CENTRAL. 1. La disposición rítmica de Génesis 1,3-31. 1.1. Ritmo. 1.2. Diseminación. 2. Una hipótesis sobre el procedimiento de construcción de Génesis 1,3-31. 3. El sentido de la presencia de los elementos rítmicos y de los diseminados. 3.1. La presencia de los días. 3.2. La presencia de las acciones. 3.2.1. Las seis acciones centrales. 3.2.2. Las dos acciones marginales. 3.3. La estructura de cada acción creadora. 3.3.1. «Y dijo Dios». 3.3.2. «Y fue así». 3.3.3. Las operaciones con las que Dios crea. 3.3.4. «Y llamó». «Y vio». 4. Progresión temática. II. LAS SECCIONES MARGINALES. CONCLUSIONES

    Circadian and Metabolic Effects of Light: Implications in Weight Homeostasis and Health

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    Daily interactions between the hypothalamic circadian clock at the suprachiasmatic nucleus (SCN) and peripheral circadian oscillators regulate physiology and metabolism to set temporal variations in homeostatic regulation. Phase coherence of these circadian oscillators is achieved by the entrainment of the SCN to the environmental 24-h light:dark (LD) cycle, coupled through downstream neural, neuroendocrine, and autonomic outputs. The SCN coordinate activity and feeding rhythms, thus setting the timing of food intake, energy expenditure, thermogenesis, and active and basal metabolism. In this work, we will discuss evidences exploring the impact of different photic entrainment conditions on energy metabolism. The steady-state interaction between the LD cycle and the SCN is essential for health and wellbeing, as its chronic misalignment disrupts the circadian organization at different levels. For instance, in nocturnal rodents, non-24 h protocols (i.e., LD cycles of different durations, or chronic jet-lag simulations) might generate forced desynchronization of oscillators from the behavioral to the metabolic level. Even seemingly subtle photic manipulations, as the exposure to a "dim light" scotophase, might lead to similar alterations. The daily amount of light integrated by the clock (i.e., the photophase duration) strongly regulates energy metabolism in photoperiodic species. Removing LD cycles under either constant light or darkness, which are routine protocols in chronobiology, can also affect metabolism, and the same happens with disrupted LD cycles (like shiftwork of jetlag) and artificial light at night in humans. A profound knowledge of the photic and metabolic inputs to the clock, as well as its endocrine and autonomic outputs to peripheral oscillators driving energy metabolism, will help us to understand and alleviate circadian health alterations including cardiometabolic diseases, diabetes, and obesity.Fil: Plano, Santiago Andrés. Pontificia Universidad Católica Argentina "Santa María de los Buenos Aires". Instituto de Investigaciones Biomédicas. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas; ArgentinaFil: Casiraghi, Leandro Pablo. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Cronobiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Garcia Moro, Paula. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Cronobiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Paladino, Natalia. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Cronobiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Golombek, Diego Andrés. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Cronobiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Chiesa, Juan José. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Cronobiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

    Interconexiones eléctricas y su enfoque regulatorio analizados desde el derecho comparado

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    Artículo de reflexiónEste artículo aborda la regulación sobre interconexiones eléctricas que se ha dado en materia regional, analizando detalladamente las características que han implementado los diversos mercados regionales para llevar a cabo de manera efectiva intercambios de electricidad, de igual manera plantea unas alternativas regulatorias que podrían ser tenidas en cuenta en el desarrollo del proyecto SINEA que actualmente desarrolla el marco regulatorio para interconexiones eléctricas entre los países miembros CAN.INTRODUCCIÓN 1. CONSIDERACIONES PREVIAS 2. ORIGEN DE LA ENERGIA Y EL MERCADO 3. TRANSACCIONES INTERNACIONALES DE ELECTRICIDAD 4. CARACTERIZACION DE LAS INTERCONEXIONES ELECTRICAS 5. PRACTICAS COLOMBIANAS EN CUANTO A INTERCONEXION ELECTRICA CONCLUSIONES BIBLIOGRAFIAPregradoAbogad

    Air gap influence on the vibro-acoustic response of Solar Arrays during launch

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    One of the primary elements on the space missions is the electrical power subsystem, for which the critical component is the solar array. The behaviour of these elements during the ascent phase of the launch is critical for avoiding damages on the solar panels, which are the primary source of energy for the satellite in its final configuration. The vibro-acoustic response to the sound pressure depends on the solar array size, mass, stiffness and gap thickness. The stowed configuration of the solar array consists of a multiple system composed of structural elements and the air layers between panels. The effect of the air between panels on the behaviour of the system affects the frequency response of the system not only modifying the natural frequencies of the wings but also as interaction path between the wings of the array. The usual methods to analyze the vibro-acoustic response of structures are the FE and BE methods for the low frequency range and the SEA formulation for the high frequency range. The main issue in the latter method is, on one hand, selecting the appropriate subsystems, and, on the other, identifying the parameters of the energetic system: the internal and coupling loss factors. From the experimental point of view, the subsystems parameters can be identified by exciting each subsystem and measuring the energy of all the subsystems composing the Solar Array. Although theoretically possible, in practice it is difficult to apply loads on the air gaps. To analyse this situation, two different approaches can be studied depending on whether the air gaps between the panels are included explicitly in the problem or not. For a particular case of a solar array of three wings in stowed configuration both modelling philosophies are compared. This stowed configuration of a three wing solar arrays in stowed configuration has been tested in an acoustic chamber. The measured data on the solar wings allows, in general, determining the loss factors of the configuration. The paper presents a test description and measurements on the structure, in terms of the acceleration power spectral density. Finally, the performance of each modelling technique has been evaluated by comparison between simulations with experimental results on a spacecraft solar array and the influence on the apparent properties of the system in terms of the SEA loss factors has been analyse

    Poder de mercado en mercados spot de generación eléctrica: metodología para su análisis

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    Después de analizar las experiencias internacionales relacionadas con el monitoreo y control de poder de mercado, se establece una metodología acorde a las características del pool eléctrico en Colombia, la cual permite hacer seguimiento sobre comportamientos estratégicos respecto al precio en bolsa en este mercado. Se propone un modelo exponencial para la función de oferta en el pool basado en un modelo de precios spot, explicado por los costos, las condiciones climáticas, las intervenciones de la Comisión de Regulación de Energía y Gas, la demanda diaria, las cantidades generadas y el precio histórico. Por medio de una convolución (técnica similar a la de un Filtro de Kalman) sobre los precios históricos se estiman los parámetros y elasticidades dinámicas asociadas a las cantidades que determinan el comportamiento del precio en bolsa. A su vez, estas estimaciones son utilizadas en la estructura de beneficios en un modelo de Cournot, de competencia en cantidades, que evidencia el efecto positivo, vía disminución del precio de bolsa, de mayores niveles de contratos a futuros en el pool eléctrico colombiano

    New lanthanide phosphonates structures obtained using XRPD data

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    5 páginas, 2 figuras, 3 tablas.-- Trabajo presentado como póster a la 12th European Powder Diffraction Conference (EPDIC 2010).-- et al.Seven lanthanide diphosphonates, [H3N(CH2)4NH3]Ln[hedpH][hedpH2] (Ln = La, Pr, Sm, Eu, Gd, Tb, Er; hedp = 1 hydroxyethylidenediphosphonate) have been synthesized with 1,4-diaminobutane as the template. The structures were obtained starting from the known X-ray single crystal model of lanthanum compound, with the X-ray powder diffraction data for these seven compounds. H-atoms were introduced using geometrical considerations. Rietveld fits of the experimental diffractograms confirm the isostructurality of all compounds in the series, and show the different behaviour between the two distances M-M existing in the structures.Financial support from Spanish MICINN (MAT2006-01997, MAT2010-15095 and ‘Factoría de Cristalización’ Consolider Ingenio 2010), Un-iversidad de Oviedo and Banco Santander is acknowledged. FEDER support is also acknowledged.Peer reviewe

    A density functional theory insight towards the rational design of ionic liquids for SO2 capture

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    A systematic density functional theory (DFT) analysis has been carried out to obtain information at the molecular level on the key parameters related to efficient SO2 capture by ionic liquids (ILs). A set of 55 ILs, for which high gas solubility is expected, has been selected. SO2 solubility of ILs was firstly predicted based on the COSMO-RS (Conductor-like Screening Model for Real Solvents) method, which provides a good prediction of gas solubility data in ILs without prior experimental knowledge of the compounds' features. Then, interactions between SO2 and ILs were deeply analyzed through DFT simulations. This work provides valuable information about required factors at the molecular level to provide high SO2 solubility in ILs, which is crucial for further implementation of these materials in the future. In our opinion, systematic research on ILs for SO2 capture increases our knowledge about those factors which could be controlled at the molecular level, providing an approach for the rational design of task-specific ILs.Ministerio de Economı´a y Competitividad (Spain, project CTQ2013-40476-R) and Junta de Castilla y León (Spain, project BU324U14

    High-pressure, low-abundance water in bipolar outflows. Results from a Herschel-WISH survey

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    (Abridged) We present a survey of the water emission in a sample of more than 20 outflows from low mass young stellar objects with the goal of characterizing the physical and chemical conditions of the emitting gas. We have used the HIFI and PACS instruments on board the Herschel Space Observatory to observe the two fundamental lines of ortho-water at 557 and 1670 GHz. These observations were part of the "Water In Star-forming regions with Herschel" (WISH) key program, and have been complemented with CO and H2 data. We find that the emission from water has a different spatial and velocity distribution from that of the J=1-0 and 2-1 transitions of CO, but it has a similar spatial distribution to H2, and its intensity follows the H2 intensity derived from IRAC images. This suggests that water traces the outflow gas at hundreds of kelvins responsible for the H2 emission, and not the component at tens of kelvins typical of low-J CO emission. A warm origin of the water emission is confirmed by a remarkable correlation between the intensities of the 557 and 1670 GHz lines, which also indicates the emitting gas has a narrow range of excitations. A non-LTE radiative transfer analysis shows that while there is some ambiguity on the exact combination of density and temperature values, the gas thermal pressure nT is constrained within less than a factor of 2. The typical nT over the sample is 4 10^{9} cm^{-3}K, which represents an increase of 10^4 with respect to the ambient value. The data also constrain within a factor of 2 the water column density. When this quantity is combined with H2 column densities, the typical water abundance is only 3 10^{-7}, with an uncertainty of a factor of 3. Our data challenge current C-shock models of water production due to a combination of wing-line profiles, high gas compressions, and low abundances.Comment: 21 pages, 13 figures. Accepted for publication in A&
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