La “otra” sociedad en Costa Rica: un estudio sobre la discriminación social en el contexto geohistórico

Este artículo trata el tema de la discriminación social dentro de la sociedad costarricense en el contexto geohistórico. Costa Rica se visualizaba como un país unificado caracterizado por su igualdad social, así como su identidad étnica, sin embargo dentro de la sociedad existía un rechazo hacia la gente que no se consideraba “nosotros” quedándose como “otros”. Dentro de la historia de la sociedad costarricense, el concepto de “nosotros” siempre se refería a los eurodescendientes, mientras que el concepto de “otros” fue evolucionando como respuesta a los procesos inmigratorios de los “no deseados” que se fueron presentando dentro del territorio costarricense.Para explicar el desarrollo de la discriminación social que se presentó dentro de la historia costarricense, este artículo trabaja sobre el origen de la discriminación social en la región, evolución de la inmigración y discriminación social hacia “otra sociedad”, así como la situación actual enfocando a los inmigrantes nicaragüenses que predominan en el panorama actual de la composición migratoria en Costa Rica

Evaluating the Finite Sample Properties of Baseline Covariate Adjustment in Randomized Trials: Application to Time to Event Outcomes

In two-arm randomized controlled trials (RCTs) with baseline covariates that are prognostic for the outcome of interest, baseline covariate adjustment can improve precision of the estimated marginal treatment effect and increase statistical power, for a fixed sample size. Many adjusted estimators for the marginal treatment effect have been proposed for a variety of outcomes and the statistical properties of these estimators have been demonstrated via simulation studies in large sample RCTs. However, there is little guidance on the use of these adjusted estimators in RCTs with small sample sizes. Motivated by an ongoing RCT (TREAT Parents trial), we conduct a simulation study to evaluate the statistical behavior of adjusted estimators for both time to event and binary outcomes in small sample RCTs, using the adjusted estimator for the marginal log hazard ratio proposed by Lu an Tsiatis (2008) for the primary time to event endpoint and several adjusted estimators of the marginal risk difference for the secondary binary endpoint. We considered hypothetical trials with small effective sample sizes, i.e. the expected number of events, ranging from 20 to 100. We also considered 3 scenarios with varying degrees of correlation between the baseline covariates and the primary and secondary outcomes, including the scenario where the baseline covariates are independent of the outcomes. The hypothetical trials were generated in ways that mimic the observed characteristics within TREAT Parents trial. Our simulation results demonstrated that precision gains in the estimated marginal treatment effect can be achieved when adjusting for baseline variables that are correlated with the outcome at effective sample sizes greater than 30. However, the potential precision gains depend on the strength of the assumed correlation between the baseline covariates and the outcome. For small effective sample sizes, the potential loss in precision when using an adjusted estimator when the baseline covariates are uncorrelated with the outcome can be roughly the same size of the precision gain under an assumption of modest correlation. We demonstrate the use of a simple simulation setting that may be used by researchers interested in evaluating the use of an adjusted estimator in a small sample RCT

Bucillamine prevents cisplatin-induced ototoxicity through induction of glutathione and antioxidant genes.

Bucillamine is used for the treatment of rheumatoid arthritis. This study investigated the protective effects of bucillamine against cisplatin-induced damage in auditory cells, the organ of Corti from postnatal rats (P2) and adult Balb/C mice. Cisplatin increases the catalytic activity of caspase-3 and caspase-8 proteases and the production of free radicals, which were significantly suppressed by pretreatment with bucillamine. Bucillamine induces the intranuclear translocation of Nrf2 and thereby increases the expression of γ-glutamylcysteine synthetase (γ-GCS) and glutathione synthetase (GSS), which further induces intracellular antioxidant glutathione (GSH), heme oxygenase 1 (HO-1) and superoxide dismutase 2 (SOD2). However, knockdown studies of HO-1 and SOD2 suggest that the protective effect of bucillamine against cisplatin is independent of the enzymatic activity of HO-1 and SOD. Furthermore, pretreatment with bucillamine protects sensory hair cells on organ of Corti explants from cisplatin-induced cytotoxicity concomitantly with inhibition of caspase-3 activation. The auditory-brainstem-evoked response of cisplatin-injected mice shows marked increases in hearing threshold shifts, which was markedly suppressed by pretreatment with bucillamine in vivo. Taken together, bucillamine protects sensory hair cells from cisplatin through a scavenging effect on itself, as well as the induction of intracellular GSH

Pathology of C3 Glomerulopathy

C3 glomerulopathy is a renal disorder involving dysregulation of alternative pathway complement activation. In most instances, a membranoproliferative pattern of glomerular injury with a prevalence of C3 deposition is observed by immunofluorescence microscopy. Dense deposit disease (DDD) and C3 glomerulonephritis (C3GN) are subclasses of C3 glomerulopathy that are distinguishable by electron microscopy. Highly electron-dense transformation of glomerular basement membrane is characteristic of DDD. C3GN should be differentiated from post-infectious glomerulonephritis and other immune complex-mediated glomerulonephritides showing C3 deposits

Empirical Validation of Heat Transfer Performance Simulation of Graphite/PCM Concrete Materials for Thermally Activated Building System

To increase the heat capacity in lightweight construction materials, a phase change material (PCM) can be introduced to building elements. A thermally activated building system (TABS) with graphite/PCM concrete hollow core slab is suggested as an energy-efficient technology to shift and reduce the peak thermal load in buildings. An evaluation of heat storage and dissipation characteristics of TABS in graphite/PCM concrete has been conducted using dynamic simulations, but empirical validation is necessary to acceptably predict the thermal behavior of graphite/PCM concrete. This study aimed to validate the thermal behavior of graphite/PCM concrete through a three-dimensional transient heat transfer simulation. The simulation results were compared to experimental results from previous studies of concrete and graphite/PCM concrete. The overall thermal behavior for both materials was found to be similar to experiment results. Limitations in the simulation modeling, which included determination of the indoor heat transfer coefficient, assumption of constant thermal conductivity with temperature, and assumption of specimen homogeneity, led to slight differences between the measured and simulated results