567 research outputs found

    Distribution of melanopsin positive neurons in pigmented and albino mice: evidence for melanopsin interneurons in the mouse retina.

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    Here we have studied the population of intrinsically photosensitive retinal ganglion cells (ipRGCs) in adult pigmented and albino mice. Our data show that although pigmented (C57Bl/6) and albino (Swiss) mice have a similar total number of ipRGCs, their distribution is slightly different: while in pigmented mice ipRGCs are more abundant in the temporal retina, in albinos the ipRGCs are more abundant in superior retina. In both strains, ipRGCs are located in the retinal periphery, in the areas of lower Brn3a(+)RGC density. Both strains also contain displaced ipRGCs (d-ipRGCs) in the inner nuclear layer (INL) that account for 14% of total ipRGCs in pigmented mice and 5% in albinos. Tracing from both superior colliculli shows that 98% (pigmented) and 97% (albino) of the total ipRGCs, become retrogradely labeled, while double immunodetection of melanopsin and Brn3a confirms that few ipRGCs express this transcription factor in mice. Rather surprisingly, application of a retrograde tracer to the optic nerve (ON) labels all ipRGCs, except for a sub-population of the d-ipRGCs (14% in pigmented and 28% in albino, respectively) and melanopsin positive cells residing in the ciliary marginal zone (CMZ) of the retina. In the CMZ, between 20% (pigmented) and 24% (albino) of the melanopsin positive cells are unlabeled by the tracer and we suggest that this may be because they fail to send an axon into the ON. As such, this study provides the first evidence for a population of melanopsin interneurons in the mammalian retina

    Exact solution of the Schrodinger equation with the spin-boson Hamiltonian

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    We address the problem of obtaining the exact reduced dynamics of the spin-half (qubit) immersed within the bosonic bath (enviroment). An exact solution of the Schrodinger equation with the paradigmatic spin-boson Hamiltonian is obtained. We believe that this result is a major step ahead and may ultimately contribute to the complete resolution of the problem in question. We also construct the constant of motion for the spin-boson system. In contrast to the standard techniques available within the framework of the open quantum systems theory, our analysis is based on the theory of block operator matrices.Comment: 9 pages, LaTeX, to appear in Journal of Physics A: Mathematical and Theoretica

    Stabilized vortex solitons in layered Kerr media

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    In this letter we demonstrate the possibility of stabilizing beams with angular momentum propagating in Kerr media. Large propagation distances without filamentation can be achieved in layered media with alternating focusing and defocusing nonlinearities. Stronger stabilization can be obtained with the addition of an incoherent beam.Comment: 4 pages, 3 figures. We have removed the sentence "Thus, they erroneously point out to the existence of fully stabilized vortex solitons" in page 2, column 2, line 7-8, because it might be confusin

    Stabilization of high-order solutions of the cubic Nonlinear Schrodinger Equation

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    In this paper we consider the stabilization of non-fundamental unstable stationary solutions of the cubic nonlinear Schrodinger equation. Specifically we study the stabilization of radially symmetric solutions with nodes and asymmetric complex stationary solutions. For the first ones we find partial stabilization similar to that recently found for vortex solutions while for the later ones stabilization does not seem possible

    Efecto de un inhibidor de la vía paracelular (2, 4, 6 Triaminopirimidina) sobre el movimiento de agua y electrolitos en íleon y colon de conejo “in vitro” e “in vivo”

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    Se estudia la influencia de un inhibidor de la vía paracelular 2, 4, 6 Triaminopirimidina (T AP) sobre el movimiento de agua y electrolitos en ileon distal y colon proximal de conejo "in vitro" e "in vivo". "In vitro" el TAP disminuye marcadamente la absorción de sodio, cloruro y aumenta la secreción de potasio, inviertiendo la transferencia de bicarbonato hacia la secreción. "In vivo" el T AP a nivel ileal tiene un efecto similar al indicado "in vitro", si bien las diferencias son menos importantes, mientras que a nivel de colon ocurre todo lo contrario, aunque estos cambios no son importantes.The influence of an inhibitor of the paracellular pathways (2, 4, 6 Triaminopirimidine, T AP) on the movemente of water and electrolytes, in distal ileum and proximal colon of rabbit "in vitro" and "in vivo", have been studied. "In vitro" the TAP significantly decreased the absorption of sodium, chloride and raised the secretion of potassium, reversing the transference of bicarbonate to the secretion, both in ileum and colon. "In vivo" the T AP at ileal level had a similar effect than "in vitro", al though the differences were less important. In the colon the changes were just the opposite, but they were no significative differences

    Efecto de un inhibidor de la vía paracelular (2, 4, 6 Triaminopirimidina) sobre el movimiento de agua y electrolitos en íleon y colon de conejo “in vitro” e “in vivo”

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    The influence of an inhibitor of the paracellular pathways (2, 4, 6 Triaminopirimidine, T AP) on the movemente of water and electrolytes, in distal ileum and proximal colon of rabbit "in vitro" and "in vivo", have been studied. "In vitro" the TAP significantly decreased the absorption of sodium, chloride and raised the secretion of potassium, reversing the transference of bicarbonate to the secretion, both in ileum and colon. "In vivo" the T AP at ileal level had a similar effect than "in vitro", although the differences were less important. In the colon the changes were just the opposite, but they were no significative differences.Se estudia la influencia de un inhibidor de la vía paracelular 2, 4, 6 Triaminopirimidina (T AP) sobre el movimiento de agua y electrolitos en ileon distal y colon proximal de conejo "in vitro" e "in vivo". "In vitro" el TAP disminuye marcadamente la absorción de sodio, cloruro y aumenta la secreción de potasio, inviertiendo la transferencia de bicarbonato hacia la secreción. "In vivo" el T AP a nivel ileal tiene un efecto similar al indicado "in vitro", si bien las diferencias son menos importantes, mientras que a nivel de colon ocurre todo lo contrario, aunque estos cambios no son importantes

    La falla de Tíscar: su significado en la terminación sudoeste del arco Prebético

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    10 páginas, 11 figuras, 1 tabla.[EN] The Tíscar fault, located towards the SW end of the Prebetic arc, is an important feature within the Betic External Zone which contributed to the separation of two different geologic domains. This fault affected the Mesozoic and Tertiary cover detached from the Palaeozoic basement and was developed as consequence of the blockage of the thrust sheets of the western border of the arc, because they could not advance farther over the basement situated progressively in a shallower position. Hence, this fault encouraged the continuation of the NW displacements in the western block, formed by Subbetic olistostromic masses and part of the Prebetic situated in the end of the arc. Although the Tíscar fault has been defined by one main line, there are in fact other parallel faults that form a broad fault zone. Its displacement began during the late Miocene and continued till Pliocene, within a near N-S compressive setting with a perpendicular extension.[ES] La falla de Tíscar, localizada en la terminación SO del arco Prebético, es un rasgo importante dentro de la Zona Externa Bética, donde ha contribuido a la separación de dos dominios geológicos diferentes. Esta falla afectó a la cobertera mesozoica y terciaria despegada del basamento paleozoico y se formó como consecuencia de que los cabalgamientos del borde occidental del arco quedaron bloqueados al no poder avanzar más sobre el basamento cada vez menos profundo. Entonces la falla permitió la continuación de los movimientos hacia el NO de su bloque occidental formado por materiales del Subbético, dispuesto en masas olistostrómicas, e incluso parte del propio Prebético del extremo del arco. Aunque la falla de Tíscar se ha definido por su traza principal, existen otras paralelas que en conjunto forman una amplia zona. Sus movimientos iniciados en el Mioceno superior continuaron hasta el Plioceno, en un contexto de compresión N-S y extensión perpendicular.Este estudio se ha financiado a través de los proyectos BTE2001-5230-E, CGL200401636/BTE, CGL2004-03333/ BTE, CGL2005-01520/BTE y BTE2001-5230-E y los grupos de la Junta de Andalucía RNM 163 y 217.Peer reviewe

    TABLERO DE PLC, PARA CAPACITACIÓN EN EL TRABAJO

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    Este trabajo se enfoca en la realización de un tablero de control eléctrico para la capacitación en el trabajo de los PLC basado en un PLC S7-1200 de Siemens. Con este tablero los participantes contaran con un referente didáctico-industrial en la capacitación para el trabajo en control eléctrico por PLC en diversos niveles educativos. Por su arquitectura abierta, apoyada para su conexión eléctrica en clemas y no en jacks, el desarrollo de este prototipo cuenta con elementos y condiciones industriales para activar los módulos de entradas y salidas del PLC. Se desarrolla el diseño y construcción de un tablero de control eléctrico para capacitación en PLC, que se adapta a diversos esquemas de habilitación laboral, dando prioridad a la instalación, operación y programación de manera respectiva. Como innovación se plantea un prototipo de tablero genérico capaz de ofrecer un entrenamiento específico a los profesionistas involucrados en la actualización a los procesos productivos controlados por relevadores y escalados a control por PLC. Palabra(s) Clave(s): capacitación para el trabajo, PLC, prototipo didáctico

    Real time approach to tunneling in open quantum systems: decoherence and anomalous diffusion

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    Macroscopic quantum tunneling is described using the master equation for the reduced Wigner function of an open quantum system at zero temperature. Our model consists of a particle trapped in a cubic potential interacting with an environment characterized by dissipative and normal and anomalous diffusion coefficients. A representation based on the energy eigenfunctions of the isolated system, i.e. the system uncoupled to the environment, is used to write the reduced Wigner function, and the master equation becomes simpler in that representation. The energy eigenfunctions computed in a WKB approximation incorporate the tunneling effect of the isolated system and the effect of the environment is described by an equation that it is in many ways similar to a Fokker-Planck equation. Decoherence is easily identified from the master equation and we find that when the decoherence time is much shorter than the tunneling time the master equation can be approximated by a Kramers like equation describing thermal activation due to the zero point fluctuations of the quantum environment. The effect of anomalous diffusion can be dealt with perturbatively and its overall effect is to inhibit tunneling.Comment: 25 pages, 1 figur

    Las fallas y pliegues recientes y activos de la parte centro-oriental de las Zonas Internas de la Cordillera Bética

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    The most recent tectonic structures of the central-eastern Internal Zones of the Betic Cordillera (from 3.1ºW to 1.7ºW and to the south of 37.525ºN) include fault and folds developed from the Late Miocene onwards, which are related to N-S/NW-SE directed continental collision and moderate thickening of a crust that is relatively hot at depth. In this setting, E-W to WSW-ENE folds, with locally associated E-W transpressive right-lateral and reverse faults, favoured the emersion of the northern Alborán basin palaeomargin and the progressive intramontane basin disconnection. The NNE-SSW to NE-SW trending regional left-lateral Palomares and Carboneras fault zones are dominant structures in the easternmost part of the cordillera. In addition, NW-SE to WNWESE trending normal and oblique-slip normal faults are widespread. The collision is still active and continues to drive active folds and faults, some probably being the likely source of moderate-sized earthquakes. The Campo de Dalías and surrounding sectors, deformed by active ENE-WSW folds and NW-SE to WNW-ESE oblique-slip normal faults, are probably the sites with the largest concentration of significant earthquakes during recent years. Moderate-magnitude earthquakes (Mw 5.0 to 6.5) have occurred there at fairly regular intervals, in 1804, 1910, and 1994. Toward the east, NW-SE trending normal faults extending from Almería to the Tabernas basin deform the Quaternary rocks with associated moderate seismicity (the 2002 Gergal Mw 4.7 earthquake, and possibly the 1894 Nacimiento earthquake, felt with intensity VII). In the Sorbas-Vera basin, the Palomares fault zone is also responsible for moderate-sized earthquakes (1518 Vera earthquake). In the Almanzora corridor, NW-SE to WNW-ESE trending Lúcar-Somontín faults also could be considered one of the possible source of moderate-magnitude seismicity (1932 Lúcar, Mw 4.8 earthquake felt with intensity VIII). Toward the east, between Albox and Partaloa, several small reverse faults and associated compressive structures deform Quaternary alluvial and fluvial sediments. Although some of these folds reveal a slow and progressive deformation from the Middle Pleistocene onwards, some of these reverse fault segments that deform the western Huércal-Overa basin could host the 1972 NW Partaloa, mbLg 4.8 earthquake, felt with intensity VII.Las estructuras tectónicas más recientes que deforman la parte centro-oriental de las Zonas Internas de Cordillera Bética (entre 3.1º y 1.7ºO y al sur de 37.525ºN) son fallas y pliegues que comenzaron a formarse aproximadamente en el Mioceno superior en un contexto de colisión continental N-S/NO-SE y moderado engrosamiento cortical. En este marco tectónico, pliegues y fallas transpresivas dextras e inversas de direcciones E-O/OSO-ENE favorecieron la emersión del borde norte de la paleocuenca de Alborán y la progresiva desconexión de pequeñas cuencas intramontañosas. Además, comenzaron a formarse las grandes zonas de falla de Palomares y Carboneras, con direcciones NNE-SSO y NE-SO respectivamente y movimientos sinistros, que también han condicionado la evolución de la Cordillera Bética oriental desde el Mioceno superior. Algunas fallas con salto normal/normal-oblicuo y trazas NO-SE/ONO-ESE también se han desarrollado ampliamente en toda la zona de estudio. La colisión, aún activa, permite que algunos pliegues y fallas continúen propagándose en la actualidad, eventualmente causando terremotos con magnitudes moderadas. El Campo de Dalías y los sectores adyacentes, deformados por pliegues activos de direcciones ENE-OSO y fallas NO-SE/ONOESE normales-oblicuas, probablemente representan la zona con mayor concentración de terremotos importantes (Mw 5.0-6.5) con eventos recurrentes en 1804, 1910 y 1994. Al este del Campo de Dalías, una amplia zona de falla normal se extiende en dirección NO-SE desde Almería hasta la cuenca de Tabernas. Esta zona de falla muestra evidencias de funcionamiento durante el Cuaternario y tiene sismicidad moderada asociada a su terminación septentrional (el terremoto de Gergal en 2002 con Mw 4.7; y posiblemente el terremoto de Nacimiento en 1894 con intensidad VII). La zona de falla de Palomares es también responsable de terremotos moderados en la Cuenca de Sorbas-Vera (terremoto de Vera en 1518). En la parte central del corredor del Almanzora, alguno de los segmentos de falla normal que se extienden entre Lúcar y Somontín podría ser responsable del terremoto de Lúcar, en 1932 (Mw 4.8 e intensidad VIII). Al este, entre Albox y Partaloa, se han descrito fallas inversas y pliegues asociados que deforman sedimentos cuaternarios. Aunque algunas de estas estructuras muestran evidencias de funcionamiento lento y progresivo durante el Cuaternario, el terremoto de Partaloa en 1972 (mbLg 4.8 e intensidad VII) pudo ser causado por la actividad de cualquiera de estos segmentos de falla inversa que deforman la parte occidental de la cuenca de Huércal-Overa
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