Chebyshev pseudospectral method for wave equation with absorbing boundary conditions that does not use a first order hyperbolic system

Abstract The analysis and solution of wave equations with absorbing boundary conditions by using a related first order hyperbolic system has become increasingly popular in recent years. At variance with several methods which rely on this transformation, we propose an alternative method in which such hyperbolic system is not used. The method consists of approximation of spatial derivatives by the Chebyshev pseudospectral collocation method coupled with integration in time by the Runge-Kutta method. Stability limits on the timestep for arbitrary speed are calculated and verified numerically. Furthermore, theoretical properties of two methods by Jackiewicz and Renaut are derived, including, in particular, a result that corrects some conclusions of these authors. Numerical results that verify the theory and illustrate the effectiveness of the proposed approach are reported

An in vitro experimental investigation of oscillatory flow in the cerebral aqueduct

This in vitro study aims at clarifying the relation between the oscillatory flow of cerebrospinal fluid (CSF) in the cerebral aqueduct, a narrow conduit connecting the third and fourth ventricles, and the corresponding interventricular pressure difference. Dimensional analysis is used in designing an anatomically correct scaled model of the aqueduct flow, with physical similarity maintained by adjusting the flow frequency and the properties of the working fluid. The time-varying pressure difference across the aqueduct corresponding to a given oscillatory flow rate is measured in parametric ranges covering the range of flow conditions commonly encountered in healthy subjects. Parametric dependences are delineated for the time-averaged pressure fluctuations and for the phase lag between the transaqueductal pressure difference and the flow rate, both having clinical relevance. The results are validated through comparisons with predictions obtained with a previously derived computational model. The parametric quantification in this study enables the derivation of a simple formula for the relation between the transaqueductal pressure and the stroke volume. This relationship can be useful in the quantification of transmantle pressure differences based on non-invasive magnetic-resonance-velocimetry measurements of aqueduct flow for investigation of CSF-related disorders.National Institutes of Health/ National Institute of Neurological Diseases and Stroke through contract # 1R01NS120343-0

Análisis crítico, comentario y ponderación valorativa de la actual Constitución de San Juan

La Corte Supremade Justicia dela Naciónha definido ala República Argentinacomo un “Estado de Derecho”, tipificándolo como aquél que: (a) posee un orden jurídico; (b) que sea justo; (c) que tenga vigencia efectiva; y (d) en el que se sancionen  las transgresiones a tal orden normativo.Desde nuestra óptica, un genuino Estado de Derecho es una zona de convergencia e interacción no declamada sino real entre el Derecho,la Constitución, la democracia y la efectiva protección de los derechos fundamentales.En consecuencia, resulta esencial que cada uno de los miembros integrantes del sistema federal argentino –nos referimos en particular a las provincias- materialicen una Constitución con una clara metodología y que además resulte –en lo posible- de sencilla y práctica interpretación y aprehensión, revelando sus contenidos axiológicos e ideológicos. En esa línea, es deseable que las Constituciones provinciales sean comprensibles y asequibles, a fin de que las políticas de Estado y el accionar de los habitantes dela República puedan adecuarse más fácilmente a su contenido y objetivos.Por lo demás, es sabido que los derechos sólo pueden ser ejercidos si son conocidos. De allí la necesidad de ponderar el grado de conocimiento que los habitantes tienen dela Norma Básicaprovincial y la percepción que poseen respecto del nivel de acatamiento de la misma por parte de los gobernantes.Tomando los citados insumos como plataforma de lanzamiento, hemos considerado de interés desarrollar un exhaustivo estudio histórico, jurídico, político, institucional, ideológico y sociológico dela Constituciónde San Juan, como una iniciativa que pueda representar siquiera un mínimo aporte a la sociedad para lograr la comprensión de la esencia de aquélla y coadyuvar a la generación de conductas consistentes con sus postulados, principios y valores.Persuadidos de quela Constituciónse identifica (o debería identificarse) con sus ciudadanos, y éstos reconocerse en ella, y ante la ausencia de una obra que de modo integral aborde el examen crítico y completo de aquélla, hemos estimado de gran interés llevar adelante un análisis de sus normas e instituciones y un relevamiento del modo como ellas han sido interpretadas porla Cortede Justicia provincial, máximo órgano de justicia local.En el proceso de investigación que nos hemos propuesto no estarán ausentes las fuentes y la historia política que subyace a la aplicación de la Constituciónprovincial, el análisis normativo y doctrinario de ésta, el examen de fallos relevantes de la Corte Supremade Justicia de la Nacióny de los órganos internacionales de protección de los derechos humanos (particularmente, de la Comisióny la Corte Interamericanasde Derechos Humanos) que se irradian hacia los órganos locales.A lo señalado. Agregamos la plena convicción de que siendo considerada un instrumento de gobierno, pero además un núcleo de valores y la prenda de unión de sanjuaninos,la Constituciónes siempre perfectible; por lo que se prestará suma atención a si finalmente resulta necesario perfeccionar su contenido literal y readaptarla ideológicamente al ritmo de las nuevas demandas del estado Constitucional de Derecho y las crecientes exigencias de la protección de los derechos fundamentales.

Nuevo atlas de radiación solar de la Pampa Húmeda argentina: resultados preliminares

El Grupo de Estudios de la Radiación Solar (GERSolar) de la Universidad Nacional de Luján ha confeccionado un nuevo Atlas de Radiación Solar de la Pampa Húmeda Argentina, el cual incluye 12 cartas mensuales y una anual que dan cuenta de los niveles diarios medios de irradiación solar en plano horizontal a nivel de la superficie terrestre. La información ha sido obtenida a través de las estaciones que el GERSolar y el INTA operan en la llanura Pampeana y corresponde a más de siete años de mediciones realizadas con instrumental de primera calidad en diez sitios de la provincia de Buenos Aires, Santa Fe, Entre Ríos, Córdoba y La Pampa. Se analiza la validez de la información presentada y se compara el potencial solar de la región con otros sitios de Argentina y el mundo.The Solar Radiation Studies Group (GERSolar) of the National University of Luján has created a new Atlas of Solar Radiation of the Pampas Húmeda Argentina, which includes 12 monthly letters and an annual one that offers the account of the new means of communication solar irradiation in a horizontal plane at the level of the earth's surface. The information has been obtained through the stations that the GERSolar and the INTA operates in the Pampeana plain and the correspondence to more than seven years of measurements made with first quality instruments in ten sites in the province of Buenos Aires, Santa Fe, Entre Ríos, Córdoba and La Pampa. The validity of the information presented is analyzed and the solar potential of the region is compared with other sites in Argentina and the world.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

Elovanoids counteract inflammatory signaling, autophagy, endoplasmic reticulum stress, and eenescence gene programming in human nasal epithelial cells exposed to allergens

To contribute to further understanding the cellular and molecular complexities of inflammatory-immune responses in allergic disorders, we have tested the pro-homeostatic elovanoids (ELV) in human nasal epithelial cells (HNEpC) in culture challenged by several allergens. ELV are novel bioactive lipid mediators synthesized from the omega-3 very-long-chain polyunsaturated fatty acids (VLC-PUFA,n-3). We ask if: (a) several critical signaling events that sustain the integrity of the human nasal epithelium and other organ barriers are perturbed by house dust mites (HDM) and other allergens, and (b) if ELV would participate in beneficially modulating these events. HDM is a prevalent indoor allergen that frequently causes allergic respiratory diseases, including allergic rhinitis and allergic asthma, in HDM-sensitized individuals. Our study used HNEpC as an in vitro model to study the effects of ELV in counteracting HDM sensitization resulting in inflammation, endoplasmic reticulum (ER) stress, autophagy, and senescence. HNEpC were challenged with the following allergy inducers: LPS, poly(I:C), or Dermatophagoides farinae plus Dermatophagoides pteronyssinus extract (HDM) (30 µg/mL), with either phosphate-buffered saline (PBS) (vehicle) or ELVN-34 (500 nM). Results show that ELVN-34 promotes cell viability and reduces cytotoxicity upon HDM sensitization of HNEpC. This lipid mediator remarkably reduces the abundance of pro-inflammatory cytokines and chemokines IL-1β, IL-8, VEGF, IL-6, CXCL1, CCL2, and cell adhesion molecule ICAM1 and restores the levels of the pleiotropic anti-inflammatory IL-10. ELVN-34 also lessens the expression of senescence gene programming as well as of gene transcription engaged in pro-inflammatory responses. Our data also uncovered that HDM triggered the expression of key genes that drive autophagy, unfolded protein response (UPR), and matrix metalloproteinases (MMP). ELVN-34 has been shown to counteract these effects effectively. Together, our data reveal a novel, pro-homeostatic, cell-protective lipid-signaling mechanism in HNEpC as potential therapeutic targets for allergies

Efecto de los protocolos ketamina-midazolam / tiletamina-zolazepam sobre los parámetros fisiológicos en tortugas Chelonoidis carbonaria sometidas a procedimientos exploratorios de rutina

The aim of this study was to determine the effect of the ketamine-midazolam / tiletamine-zolazepam protocols on physiological parameters (respiratory rate, heart rate, partial oxygen saturation and central and peripheral temperature) in Chelonoidis carbonaria turtles subjected to routine exploratory procedures (swab rectal and buccal). Twenty turtles were randomly distributed into two groups: Group 1: ketamine + midazolam and Group 2: tiletamine + zolazepam intramuscularly. The results were evaluated according to time and treatment, as well as the time-treatment interaction. Significant differences were found between protocols for the variables of respiratory rate and heart rate (p<0.05), but not for the variables of partial oxygen saturation (Sp O2) and central and peripheral temperature (p>0.05).El estudio tuvo como objetivo determinar el efecto de los protocolos ketamina-midazolam / tiletamina-zolazepam sobre parámetros fisiológicos (frecuencia respiratoria, frecuencia cardíaca, saturación parcial de oxígeno y temperatura central y periférica) en tortugas Chelonoidis carbonaria sometidas a procedimientos exploratorios de rutina (hisopado rectal y bucal). Se utilizaron 20 tortugas distribuidas al azar en dos grupos: Grupo 1: ketamina + midazolam y Grupo 2: tiletamina + zolazepam vía intramuscular. Los resultados fueron evaluados en función al tiempo y al tratamiento, así como en la interacción tiempo-tratamiento. Se encontraron diferencias significativas entre protocolos para las variables de frecuencia respiratoria y frecuencia cardiaca (p<0.05), mas no así para las variables de saturación parcial de oxigeno (Sp O2), temperatura central y periférica (p>0.05)

Calidad del Agua de Consumo en el Gran La Plata, Buenos Aires, Argentina. El Problema de los Nitratos

This work establishes the variation of quality of drinking water in its physicist-chemist aspect, comparing results between samples taken in the year 1997 and 2008. It is notable the growth of nitrates in the year 2008 than 1997. The concentration of silica allows to distinguish the origin of consumption water: of river, mix water or underground water.El presente trabajo establece la variación de la calidad del agua de consumo en su aspecto fisicoquímico, comparando resultados entre muestras tomadas en los años 1997 y 2008. Se nota el incremento de los nitratos en el año 2008 con respecto al año 1997. La concentración de sílice permite distinguir el origen del agua de consumo: de río, agua de mezcla o agua subterránea

Adaptive refinement and selection process through defect localization for reconstructing an inhomogeneous refraction index

We consider the iterative reconstruction of both the internal geometry and the values of an inhomogeneous acoustic refraction index through a piecewise constant approximation. In this context, we propose two enhancements intended to reduce the number of parameters to reconstruct, while preserving accuracy. This is achieved through the use of geometrical informations obtained from a previously developed defect localization method. The first enhancement consists in a preliminary selection of relevant parameters, while the second one is an adaptive refinement to enhance precision with a low number of parameters. Each of them is numerically illustrated

Performance of a commercial polymerase chain reaction test for endocervical Chlamydia trachomatis infection in a university hospital population.

OBJECTIVES: To examine the accuracy of a commercial polymerase chain reaction (PCR) test (Amplicor CTR, Roche Diagnostic Systems, Branchburg NJ) for identification of endocervical chlamydial infections through both laboratory evaluation and among a diverse teaching hospital patient population. METHODS: Testing of reliable threshold inocula and reproducibility were carried out using laboratory stock organisms. Paired endocervical samples from patients with a wide range of indications were tested by PCR and an established culture procedure, and discrepant pairs were further analyzed to determine true results. RESULTS: Laboratory evaluation suggested that one copy of target DNA from a viable organism consistently yielded a positive result, and test reproducibility was very good, with an overall coefficient of variation of 15%. Compared to true results in 1,588 paired clinical samples from 1,489 women with a 10% prevalence of infection, the PCR test and culture yielded respective sensitivities of 87.4% and 78.0%, and negative predictive values of 98.6% and 97.6%. Specificity and positive predictive value for both tests were 100%. Cost per specimen was nearly identical at $18.84 and$18.88 respectively. Polymerase inhibitors and organisms lacking target DNA were not found in false-negative PCR samples. CONCLUSION: This commercial PCR test is accurate, cost-competitive, and much faster than culture for diagnosis of endocervical chlamydia infections in our population of intermediate prevalence of chlamydial infection