Wave equation and dispersion relations for a compressible rotating fluid

A fundamental non-classical fourth-order partial differential equation to describe small amplitude linear oscillations in a rotating compressible fluid, is obtained. The dispersion relations for such a fluid, and the different regions of the group and phase velocity are analyzed.Comment: 9 page

Climate model simulation of winter warming and summer cooling following the 1991 Mount Pinatubo volcanic eruption

We simulate climate change for the 2-year period following the eruption of Mount Pinatubo in the Philippines on June 15, 1991, with the ECHAM4 general circulation model (GCM). The model was forced by realistic aerosol spatial-time distributions and spectral radiative characteristics calculated using Stratospheric Aerosol, and Gas Experiment II extinctions and Upper Atmosphere Research Satellite-retrieved effective radii. We calculate statistical ensembles of GCM simulations with and without volcanic aerosols for 2 years after the eruption for three different sea surface temperatures (SSTs): climatological SST, El Nino-type SST of 1991-1993, and La Nina-type SST of 1984-1986. We performed detailed comparisons of calculated fields with observations, We analyzed the atmospheric response to Pinatubo radiative forcing and the ability of the GCM to reproduce it with different SSTs. The temperature of the tropical lower stratosphere increased by 4 K because of aerosol absorption of terrestrial longwave and solar near-infrared radiation. The heating is larger than observed, but that is because in this simulation we did not account for quasi-biennial oscillation (QBO) cooling and the cooling effects of volcanically induced ozone depletion. We estimated that both QBO and ozone depletion decrease the stratospheric temperature by about 2 K. The remaining 2 K stratospheric warming is in good agreement with observations. By comparing the runs with the Pinatubo aerosol forcing with those with no aerosols, we find that the model calculates a general cooling of the global troposphere, but with a clear winter warming pattern of surface air temperature over Northern Hemisphere continents. This pattern is consistent with the observed temperature patterns. The stratospheric heating and tropospheric summer cooling are directly caused by aerosol radiative effects, but the winter warming is indirect, produced by dynamical responses to the enhanced stratospheric latitudinal temperature gradient. The aerosol radiative forcing, stratospheric thermal response, and summer tropospheric cooling do not depend significantly on SST. The stratosphere-troposphere dynamic interactions and tropospheric climate response in winter are sensitive to SST

Augustana Seniors Fall 1884: Carl August Blomgren

Carl August Blomgren was a senior at Augustana College, Rock Island, Illinois, in the fall of 1884. His name appears in the college catalog of 1884 – 1885, along with his birthplace, the year of his birth, and a few other facts. From this start, we researched the genealogy and family history of Blomgren. This paper contains a short biography of C.A. Blomgren, a report on his ancestors, a report on his descendants, and some open questions for further researc

La intervención del primer franquismo sobre la fiesta popular: una aproximación a través del caso asturiano (1937-1945)

Resumen: La intervención del calendario festivo es una pieza clave de la estrategia diseñada por el régimen franquista para el perfeccionamiento de su control sobre la población española. Dicha intervención, ampliamente estudiada para las grandes celebraciones de alcance nacional, demanda nuevas aportaciones en lo que se refiere al átomo del tejido festivo español: la fiesta popular local. Este trabajo pretende contribuir al conocimiento de la actitud del Régimen hacia las expresiones del ocio festivo popular, a través de la imagen proyectada por el caso asturiano y aprovechando las sugerentes aportaciones de la sociología y la antropología del ocio y la fiesta. Palabras clave: fiesta popular, franquismo, Asturias, posguerra, poder simbólico. Abstract: The intervention in the festive calendar is a linchpin of the strategy designed by the Franco regime in order to improve its control over the Spanish population. Such intervention, amply studied through the great national celebrations, demands new contributions about the atom of the Spanish festive network: the local popular feast. This article pretends to contribute to the knowledge of the attitude of the Regime towards the local festive leisure of the Spanish people, through the image projected by the Asturian case and making use of the suggestive contributions offered by the sociology and anthropology of leisure and feast. Keywords: popular feast, Franco regime, Asturias, postwar period, symbolic power

Characterization of GaN-based light-emitting diodes

Maximizing the performance of light-emitting diodes (LEDs) is essential for the widespread uptake of solid-state lighting. To contribute towards this goal, this thesis focuses on the electrical and optical characterization of InGaN/GaN-based multi quantum well LEDs. In this work a wide range of characterization methodologies are introduced. A new development is the study of the emission spectra under resonant optical pumping and varying electrical bias. This has proven to be useful to obtain insights into the carrier dynamics and is used here to investigate LED samples containing different numbers of quantum wells (QWs) with different thicknesses for the barriers. Despite having only small structural differences, these samples have shown strong differences in their performance, which are attributed to a stronger piezoelectric field in the QWs in the sample with thinner barriers. Fluorescence microscopy with selective excitation of the QWs also allows the study of the spatially dependent luminescent properties of LEDs. In this case ohmic contacts create an equipotential surface and influence the collective emission. Strong carrier escape is observed in photovoltaic mode under both open and short circuit conditions. To help identify the underlying recombination mechanisms, different voltage ideality factors are extracted and compared with each other. This thesis shows that the use of photovoltaic measurements together with biasdependent spectrally resolved luminescence is a powerful tool to investigate GaN LEDs. The methodologies presented here provide experimental tools to better understand carrier recombination processes in different LED samples. These methods can extended to samples grown on different crystallographic orientations or to study the effects of additional layers in novel LED structures

Monitoreo del proceso de esterilización en unidades médicas hospitalarias

Propósito y Método de Estudio: El propósito del estudio fue observar el proceso de esterilización que se realiza con autoclaves de vapor de agua y esterilizadores de gas de óxido de etileno en las Unidades Médicas Hospitalarias de una Institución del Sector Salud en la Delegación Nuevo León y comparar con el proceso de esterilización establecido por la Institución. El marco de referencia se basó en la etapa de esterilización, la cuál se define como el proceso por medio del cual toda forma de vida microbiana (bacterias, esporas, hongos y virus), contenidos en líquidos, instrumentos o utensilios, es completamente destruida. El diseño del estudio fue de tipo exploratorio observacional, la unidad de análisis estuvo constituida por 20 autoclaves de vapor de agua y siete esterilizadores de gas de óxido de etileno disponibles en nueve Unidades Médicas Hospitalarias de una institución del Sector Salud en el estado de Nuevo León. Contribución y Conclusiones: En relación a la normatividad ubicada en el servicio se observó su cumplimiento en un 48%, el uso de los indicadores biológicos establecidos en la normatividad se presentó en un 71.2%, en relación al uso de las incubadoras adecuadas al tipo de indicador definido en la normatividad se cumple en el 88.2% y permanecen conectadas las 24 horas del día en un 90.4%. El índice de cumplimiento del proceso de esterilización reportó el menor cumplimiento para los indicadores biológicos con una media de 36.54% y (DE= 18.60) seguida de los indicadores químicos con una media de 65.95% y (DE= 16.91), para los indicadores físicos una media de 79.14 y DE=22.32, con un índice global de cumplimiento de 60.78% de media y (DE=13.41). De acuerdo a los resultados se recomienda realizar estudios de investigación de seguimiento, considerando la metodología del presente estudio para validación de parámetros físicos, control de los registros y la efectividad de la penetración del vapor, a través del control del paquete con tiras integradoras, acomodo de paquetes y funcionalidad del equipo, los cuales no fueron considerados en el presente estudio