132 research outputs found
A Double-Edge Sword? Mass Media and Nonviolent Dissent in Autocracies
It is often assumed that nondemocratic regimes will control mass media and suppress independent information, but in many autocracies the media are partially free and imperfectly controlled. We argue that partial media freedom can increase the prospects for mass nonviolent dissent. We develop a theory emphasizing how even less than perfectly free media outlets can increase the ability of individuals to coordinate and mobilize, and provide an informational endowment that can help non-state actors overcome collective mobilization barriers. We further argue that this informational endowment amplifies the effect of other influences spurring mass protests in autocracies, in particular protest contagion and elections. We find empirical support for our argument in an analysis of all autocracies between 1955 and 2013. A case study of the Georgian Rose revolution provides further support for the postulated mechanisms
Can Education Reduce Violent Crime? Evidence from Mexico before and after the Drug War Onset
Existing theories relate higher education to lower crime rates, yet we have limited evidence on the crime-reducing effect of education in developing countries. We contribute to this literature by examining the effect of education on homicide in Mexico, where homicide rates decreased by nearly 55 percent from 1992 to 2007, before the surge of drug-related violence. We argue that a large amount of this reduction followed a compulsory schooling law at the secondary level in 1993, when the government undertook key education reforms to promote development and economic integration. We employ different empirical strategies that combine regression analysis, placebo tests, and an instrumental variable approach, and find that attendance in secondary and tertiary schools has a negative effect on homicide rates before the onset of the Drug War, although the evidence for secondary enrolment is more robust. This effect vanishes after the drug war onset, indicating that school attendance has different effects on different types of criminal activity. These findings suggest that policy makers can reduce crime and traditional forms of interpersonal violence by strengthening the education system
Usefulness of the Hybrid RFR-FFR Approach: Results of a Prospective and Multicenter Analysis of Diagnostic Agreement between RFR and FFR—The RECOPA (REsting Full-Cycle Ratio Comparation versus Fractional Flow Reserve (A Prospective Validation)) Study
Cardiologia; Estudi fisiològic; EspanyaCardiología; Estudio fisiológico; EspañaCardiology; Physiological study; SpainBackground. The resting full‐cycle ratio (RFR) is a novel resting index which in contrast to the gold standard (fractional flow reserve (FFR)) does not require maximum hyperemia induction. The objectives of this study were to evaluate the agreement between RFR and FFR with the currently recommended thresholds and to design a hybrid RFR-FFR ischemia detection strategy, allowing a reduction of coronary vasodilator use. Materials and Methods. Patients subjected to invasive physiological study in 9 Spanish centers were prospectively recruited between April 2019 and March 2020. Sensitivity and specificity studies were made to assess diagnostic accuracy between the recommended levels of RFR ≤0.89 and FFR ≤0.80 (primary objective) and to determine the RFR “grey zone” in order to define a hybrid strategy with FFR affording 95% global agreement compared with FFR alone (secondary objective). Results. A total of 380 lesions were evaluated in 311 patients. Significant correlation was observed (R2 = 0.81; ) between the two techniques, with 79% agreement between RFR ≤ 0.89 and FFR ≤ 0.80 (positive predictive value, 68%, and negative predictive value, 80%). The hybrid RFR-FFR strategy, administering only adenosine in the “grey zone” (RFR: 0.86 to 0.92), exhibited an agreement of over 95% with FFR, with high predictive values (positive predictive value, 91%, and negative predictive value, 92%), reducing the need for vasodilators by 58%. Conclusions. Dichotomous agreement between RFR and FFR with the recommended thresholds is significant but limited. The adoption of a hybrid RFR-FFR strategy affords very high agreement, with minimization of vasodilator use
Utilising thermal annealing for multiplexing and sensitivity enhancement of polymer optical fibre sensors
Thermal annealing was initially introduced for multiplexing purposes, since it can induce a permanent negative Bragg wavelength shift for polymer fibre grating sensors. At a later stage, it is shown that annealing can also provide additional benefits, such as strain and humidity sensitivity enhancement and augmented temperature operational range. In this paper, we report additional usage of thermal annealing on PMMA fibre Bragg grating sensors. We show the possibility to tune Bragg wavelengths to longer wavelengths permanently by stretching the polymer optical fibre during the thermal annealing process. An array of sensors fabricated with only one phase-mask, demonstrates the concept by having Bragg wavelengths below and above the original inscribed spectral position. In addition, we report that thermal annealing can be also used to enhance the performance of sensors when used for stress and force monitoring
Impact of One-Catheter Strategy with TIG I Catheter on Coronary Catheterization Performance and Economic Costs
Background: Coronary angiography with two catheters is the traditional strategy for diagnostic coronary procedures. TIG I catheter permits to cannulate both coronary arteries, avoiding exchanging catheters during coronary angiography by transradial access. Objective: The aim of this study is to evaluate the impact of one-catheter strategy, by avoiding catheter exchange, on coronary catheterization performance and economic costs. Methods: Transradial coronary diagnostic procedures conducted from January 2013 to June 2017 were collected. One-catheter strategy (TIG I catheter) and two-catheter strategy (left and right Judkins catheters) were compared. The volume of iodinated contrast administered was the primary endpoint. Secondary endpoints included radial spasm, procedural duration (fluoroscopy time) and exposure to ionizing radiation (dose-area product and air kerma). Direct economic costs were also evaluated. For statistical analyses, two-tailed p-values < 0.05 were considered statistically significant.
Results: From a total of 1,953 procedures in 1,829 patients, 252 procedures were assigned to one-catheter strategy and 1,701 procedures to two-catheter strategy. There were no differences in baseline characteristics between the groups. One-catheter strategy required less iodinated contrast [primary endpoint; (60-105)-mL vs. 92 (64-120)-mL; p < 0.001] than the two-catheter strategy. Also, the one-catheter group presented less radial spasm (5.2% vs. 9.3%, p = 0.022) and shorter fluoroscopy time [3.9 (2.2-8.0)-min vs. 4.8 (2.9-8.3)-min, p = 0.001] and saved costs [149 (140-160)-€/procedure vs. 171 (160-183)-€/procedure; p < 0.001]. No differences in dose-area product and air kerma were detected between the groups. Conclusions: One-catheter strategy, with TIG I catheter, improves coronary catheterization performance and reduces economic costs compared to traditional two-catheter strategy in patients referred for coronary angiography
Stakeholder-driven development and implementation of CRICIT: an app to support high-quality data capture and protocol monitoring for outpatient clinical trials with vulnerable populations
Abstract
Introduction:Choosing an appropriate electronic data capture system (EDC) is a critical decision for all randomized controlled trials (RCT). In this paper, we document our process for developing and implementing an EDC for a multisite RCT evaluating the efficacy and implementation of an enhanced primary care model for individuals with opioid use disorder who are returning to the community from incarceration.
Methods:Informed by the Knowledge-to-Action conceptual framework and user-centered design principles, we used Claris Filemaker software to design and implement CRICIT, a novel EDC that could meet the varied needs of the many stakeholders involved in our study.
Results:CRICIT was deployed in May 2021 and has been continuously iterated and adapted since. CRICIT’s features include extensive participant tracking capabilities, site-specific adaptability, integrated randomization protocols, and the ability to generate both site-specific and study-wide summary reports.
Conclusions:CRICIT is highly customizable, adaptable, and secure. Its implementation has enhanced the quality of the study’s data, increased fidelity to a complicated research protocol, and reduced research staff’s administrative burden. CRICIT and similar systems have the potential to streamline research activities and contribute to the efficient collection and utilization of clinical research data
Ajustando RFR por Preditores de Discordância, “The Adjusted RFR”: Uma Metodologia Alternativa para Melhorar a Capacidade Diagnóstica de Índices Coronarianos
Background: Cutoff thresholds for the "resting full-cycle ratio" (RFR) oscillate in different series, suggesting that population characteristics may influence them. Likewise, predictors of discordance between the RFR and fractional flow reserve (FFR) have been documented. The RECOPA Study showed that diagnostic capacity is reduced in the RFR "grey zone", requiring the performance of FFR to rule out or confirm ischemia.
Objectives: To determine predictors of discordance, integrate the information they provide in a clinical-physiological index, the "Adjusted RFR", and compare its agreement with the FFR.
Methods: Using data from the RECOPA Study, predictors of discordance with respect to FFR were determined in the RFR "grey zone" (0.86 to 0.92) to construct an index ("Adjusted RFR") that would weigh RFR together with predictors of discordance and evaluate its agreement with FFR.
Results: A total of 156 lesions were evaluated in 141 patients. Predictors of discordance were: chronic kidney disease, previous ischemic heart disease, lesions not involving the anterior descending artery, and acute coronary syndrome. Though limited, the "Adjusted RFR" improved the diagnostic capacity compared to the RFR in the "grey zone" (AUC-RFR = 0.651 versus AUC-"Adjusted RFR" = 0.749), also showing an improvement in all diagnostic indices when optimal cutoff thresholds were established (sensitivity: 59% to 68%; specificity: 62% to 75%; diagnostic accuracy: 60% to 71%; positive likelihood ratio: 1.51 to 2.34; negative likelihood ratio: 0.64 to 0.37).
Conclusions: Adjusting the RFR by integrating the information provided by predictors of discordance to obtain the "Adjusted RFR" improved the diagnostic capacity in our population. Further studies are required to evaluate whether clinical-physiological indices improve the diagnostic capacity of RFR or other coronary indices.Fundamento: Os limiares de corte para a “relação do ciclo completo de repouso” (RFR) oscilam em diferentes séries, sugerindo que as características da população podem influenciá-los. Da mesma forma, foram documentados preditores de discordância entre a RFR e a reserva de fluxo fracionado (FFR). O Estudo RECOPA, mostrou que a capacidade diagnóstica está reduzida na “zona cinzenta” da RFR, tornando necessária a realização de FFR para descartar ou confirmar isquemia.
Objetivos: Determinar os preditores de discordância, integrar as informações que eles fornecem em um índice clínico-fisiológico: a “RFR Ajustada”, e comparar sua concordância com o FFR.
Métodos: Usando dados do Estudo RECOPA, os preditores de discordância em relação à FFR foram determinados na “zona cinzenta” da RFR (0,86 a 0,92) para construir um índice (“RFR Ajustada”) que pesaria a RFR juntamente com os preditores de discordância e avaliar sua concordância com a FFR.
Resultados: Foram avaliadas 156 lesões em 141 pacientes. Os preditores de discordância foram: doença renal crônica, cardiopatia isquêmica prévia, lesões não envolvendo a artéria descendente anterior esquerda e síndrome coronariana aguda. Embora limitada, a “RFR Ajustada” melhorou a capacidade diagnóstica em comparação com a RFR na “zona cinzenta” (AUC-RFR = 0,651 versus AUC-“RFR Ajustada” = 0,749), mostrando também uma melhora em todos os índices diagnósticos quando foram estabelecidos limiares de corte otimizados (sensibilidade: 59% a 68%; especificidade: 62% a 75%; acurácia diagnóstica: 60% a 71%; razão de verossimilhança positiva: 1,51 a 2,34; razão de verossimilhança negativa: 0,64 a 0,37).
Conclusões: Ajustar a RFR integrando as informações fornecidas pelos preditores de discordância para obter a “RFR Ajustada” melhorou a capacidade diagnóstica em nossa população. Mais estudos são necessários para avaliar se os índices clínico-fisiológicos melhoram a capacidade diagnóstica da RFR ou de outros índices coronarianos
Kinetics and Product Yields of the OH Initiated Oxidation of Hydroxymethyl Hydroperoxide
Hydroxymethyl hydroperoxide (HMHP), formed in the reaction of the C1 Criegee intermediate with water, is among the most abundant organic peroxides in the atmosphere. Although reaction with OH is thought to represent one of the most important atmospheric removal processes for HMHP, this reaction has been largely unstudied in the laboratory. Here, we present measurements of the kinetics and products formed in the reaction of HMHP with OH. HMHP was oxidized by OH in an environmental chamber; the decay of the hydroperoxide and the formation of formic acid and formaldehyde were monitored over time using CF3O- chemical ionization mass spectrometry (CIMS) and laser induced fluorescence (LIF). The loss of HMHP by reaction with OH is measured relative to the loss of 1,2-butanediol [k1;2-butanediol+OH = (27:0 5:6) 10- exp12 cm3 molecule-1s-1]. We find that HMHP reacts with OH at 295 K with a rate coefficient of (7.1 1.5) 10-12 cm3 molecule-1s-1, with the formic acid to formaldehyde yield in a ratio of 0:880:21 and independent of NO concentration (31010 1.51013 molecule cm-3). We suggest that, exclusively, abstraction of the methyl hydrogen of HMHP results in formic acid while abstraction of the hydroperoxy hydrogen results in formaldehyde. We further evaluate the relative importance of HMHP sinks and use global simulations from GEOS-Chem to estimate that HMHP oxidation by OH contributes 1.7 Tg yr-1 (1-3%) of global annual formic acid production
- …