6,564 research outputs found

    Consensus must be found on intravenous fluid therapy management in trauma patients

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    Introduction: Trauma is an important cause of death among young people and 30-40% of this mortality rate is due to hypovolemic shock, intensified by trauma's lethal triad: Hypothermia, Acidosis, and Coagulopathy. Nurses are responsible for managing fluid therapy administration in trauma victims. The purpose of this study is to analyse the reasons why intravenous fluid therapy is recommended for trauma patients' hemodynamic stabilization. Methods: This narrative literature review included published and unpublished studies in English, Spanish or Portuguese between 1994 and January 2019. The search results were analyzed by two independent reviewers. Inclusion criteria encompasses quantitative studies involving trauma victims aged over 18 who underwent fluid therapy in a prehospital assessment context. Results&Discussion: 11 quantitative studies were included. 9 involved the use of fluid therapy for hypotension treatment and 2 of the studies analyzed involved the use of warmed fluid therapy for hypothermia treatment. The analysis performed reveals that the administration of aggressive fluid therapy seems to be responsible for the worsening of the lethal triad. In the presence of traumatic brain injury, permissive hypotension is not allowed due to the negative impact on cerebral perfusion pressure. Used as warming measure, warmed fluid therapy does not seem to have a significant impact on body temperature. Conclusions: There is no consensus regarding the administration of fluid therapy to trauma patients. This conclusion clearly supports the need to develop more randomized controlled trials in order to understand the effectiveness of such measure when it comes to control hypovolemia and hypothermia.info:eu-repo/semantics/publishedVersio

    Transport and mixing simulation along the continental shelf edge using a Lagrangian approach

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    Este trabajo presenta la comprobación de un modelo bioquímico a partir de dos modelos hidrodinámicos diferentes: un modelo 1D (Coelho, 1996) y un modelo 3D (Santos, 1995), correspondientes a dos fases de trabajo sucesivas. En la primera fase el modelo hidrodinámico 1D fue usado para calibrar el modelo biogeoquímico; los resultados de esta fase permitieron el análisis de la evolución de los perfiles temporales verticales. Se usaron tanto la aproximación euleriana como la lagrangiana para el transporte de las propiedades bioquímicas. En la segunda fase 3D se aplicó el modelo hidrodinámico, lo que permitió obtener una visión a escala regional de los procesos involucrados. El transporte de las propiedades bioquímicas fue realizado a partir de la aproximación lagrangiana, habiéndose destacado el origen del agua procedente de afloramientos (upwelling). Los datos obtenidos en Goban Spur/La Chapelle durante el Ocean Margin Exchange Project (Anon., 1996) fueron usados para definir las condiciones iniciales y de contorno para los modelos bioquímicos e hidrodinámicos. Nuestra principal conclusión es que el modelo 3D de seguimiento de la dinámica de partículas, junto con el modelo hidrodinámico 3D (con un modelo de turbulencia cerrado apropiado) y con un modelo bioquímico, puede ser una excelente herramienta para cuantificar intercambios entre la plataforma continental y el océano abierto.This paper presents the coupling of a biochemical model with two different hydrodynamic models, a 1-D model (Coelho, 1996) and a 3-D model (Santos, 1995), corresponding to two successive work phases. In the first phase the 1-D hydrodynamic model was used to calibrate the biochemical model; the results of this phase made it possible to analyse temporal vertical profiles evolution. Both an Eulerian and a Lagrangian approach were used to transport biochemical properties. In the second phase, the 3-D hydrodynamic model was applied; this gave a regionalscale view of the processes involved. Biochemical properties transport was made with a Lagrangian approach, highlighting the origin of upwelled water. Goban Spur/La Chapelle field data collected during the Ocean Margin Exchange project (Anon., 1996) were used as initial and boundary conditions in hydrodynamic and biochemical models. Our main conclusion is that a 3-D particle-tracking model, coupled with a 3-D hydrodynamic model (with a proper turbulence closure model) and with a biochemical model, can be an excellent tool to quantify exchanges between the continental shelf and deep ocean.Instituto Español de Oceanografí

    Metastability and Nucleation for the Blume-Capel Model. Different mechanisms of transition

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    We study metastability and nucleation for the Blume-Capel model: a ferromagnetic nearest neighbour two-dimensional lattice system with spin variables taking values in -1,0,+1. We consider large but finite volume, small fixed magnetic field h and chemical potential "lambda" in the limit of zero temperature; we analyze the first excursion from the metastable -1 configuration to the stable +1 configuration. We compute the asymptotic behaviour of the transition time and describe the typical tube of trajectories during the transition. We show that, unexpectedly, the mechanism of transition changes abruptly when the line h=2*lambda is crossed.Comment: 96 pages, 44 tex-figures, 7 postscript figure

    X-ray method to study temperature-dependent stripe domains in MnAs/GaAs(001)

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    MnAs films grown on GaAs (001) exhibit a progressive transition between hexagonal (ferromagnetic) and orthorhombic (paramagnetic) phases at wide temperature range instead of abrupt transition during the first-order phase transition. The coexistence of two phases is favored by the anisotropic strain arising from the constraint on the MnAs films imposed by the substrate. This phase coexistence occurs in ordered arrangement alternating periodic terrace steps. We present here a method to study the surface morphology throughout this transition by means of specular and diffuse scattering of soft x-rays, tuning the photon energy at the Mn 2p resonance. The results show the long-range arrangement of the periodic stripe-like structure during the phase coexistence and its period remains constant, in agreement with previous results using other techniques.Comment: 4 pages, 4 figures, submitted to Applied Physics Letter

    Co‐existing monophasic teratoma and uterine adenocarcinoma in a female dog

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    Ovarian teratomas are occasionally reported in dogs; the rarest type is the monophasic teratoma,composed of tissues originating from only one germ layer. Canine endometrial adenocarcinomas are also rare in dogs and mainly affect geriatric females. This report describes case of co-existing ovarian teratoma and uterine adenocarcinoma in a 10-year old nulliparous female Boxer presented with lethargy, anorexia and purulent vaginal discharge. Abdominal ultrasonography evidenced pyometra and a mass in the left ovary. This was composed of a uniform whitish tissue with multiple cystic structures. The histology revealed an atrophy of the ovarian parenchyma, compressed by a proliferation of well-differentiated nervous tissue staining positively to vimentin, S100 and neuronal specific enolase (NSE), and negatively to keratin and inhibin. The left uterine horn, whose diameter was markedly increased, showed foci of endometrial cellular atypia, evident nucleoli and mitoses, at light microscopy. To our best knowledge, this is the first report of a coexisting ovarian monophasic teratoma and endometrial adenocarcinoma, two rare reproductive neoplasia in dogs

    From a magnet to a heat pump

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    The magnetocaloric effect (MCE) is the thermal response of a magnetic material to an applied magnetic field. Magnetic cooling is a promising alternative to conventional vapor compression technology in near room temperature applications and has experienced significant developments over the last five years. Although further improvements are necessary before the technology can be commercialized.Researchers were mainly focused on the development of materials and optimization of a flow system in order to increase the efficiency of magnetic heat pumps. The project, presented in this paper, is devoted to the improvement of heat pump and cooling technologies through simple tests of prospective regenerator designs. A brief literature review and expected results are presented in the paper. It is mainly focused on MCE technologies and provides a brief introduction to the magnetic cooling as an alternative for conventional vapor compression technology

    Magnetic reconfiguration of MnAs/GaAs(001) observed by Magnetic Force Microscopy and Resonant Soft X-ray Scattering

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    We investigated the thermal evolution of the magnetic properties of MnAs epitaxial films grown on GaAs(001) during the coexistence of hexagonal/orthorhombic phases using polarized resonant (magnetic) soft X-ray scattering and magnetic force microscopy. The results of the diffuse satellite X-ray peaks were compared to those obtained by magnetic force microscopy and suggest a reorientation of ferromagnetic terraces as temperature rises. By measuring hysteresis loops at these peaks we show that this reorientation is common to all ferromagnetic terraces. The reorientation is explained by a simple model based on the shape anisotropy energy. Demagnetizing factors were calculated for different configurations suggested by the magnetic images. We noted that the magnetic moments flip from an in-plane mono-domain orientation at lower temperatures to a three-domain out-of-plane configuration at higher temperatures. The transition was observed when the ferromagnetic stripe width L is equal to 2.9 times the film thickness d. This is in good agreement with the expected theoretical value of L = 2.6d.Comment: 16 pages in PD

    Analytical results for a Bessel function times Legendre polynomials class integrals

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    When treating problems of vector diffraction in electromagnetic theory, the evaluation of the integral involving Bessel and associated Legendre functions is necessary. Here we present the analytical result for this integral that will make unnecessary numerical quadrature techniques or localized approximations. The solution is presented using the properties of the Bessel and associated Legendre functions.Comment: 4 page
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