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The inverse probability of treatment weighting (IPTW) approach is commonly used in propensity score analysis to infer causal effects in regression models. Due to oversized IPTW weights and errors associated with propensity score estimation, the IPTW approach can underestimate the standard error of causal effect. To remediate this, bootstrap standard errors have been recommended to replace the IPTW standard error, but the ordinary bootstrap (OB) procedure might still result in underestimation of the standard error because of its inefficient resampling scheme and untreated oversized weights. In this paper, we develop a generalized bootstrap (GB) procedure for estimating the standard error and confidence intervals of the IPTW approach. Compared with the OB procedure and other three procedures in comparison, the GB procedure has the highest precision and yields conservative standard error estimates. As a result, the GB procedure produces short confidence intervals with highest coverage rates. We demonstrate the effectiveness of the GB procedure via two simulation studies and a dataset from the National Educational Longitudinal Study-1988 (NELS-88).
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Estudios Longitudinales , Intervalos de Confianza , Probabilidad , Puntaje de Propensión , Simulación por Computador , CausalidadRESUMEN
Introduction: Research has shown epigenetic change via alternation of the methylation profile of human skeletal muscle DNA after Cardio-Pulmonary Bypass (CPB). In this study, we investigated the change in epigenome-wide DNA methylation profiles of porcine myocardium after ischemic insult in the setting of treatment with extracellular vesicle (EV) therapy in normal vs. high-fat diet (HFD) pigs. Methods: Four groups of three pigs underwent ameroid constrictor placement to the left circumflex artery (LCx) and were assigned to the following groups: (1) normal diet saline injection; (2) normal diet EV injection; (3) HFD saline injection; and (4) HFD EV injection. DNA methylation was profiled via reduced-representation bisulfite sequencing (RRBS) and compared using a custom bioinformatic pipeline. Results: After initial analysis, 441 loci had a nominal P value < 0.05 when examining the effect of ischemia vs. normal heart tissue on a normal diet in the absence of treatment. 426 loci at P value threshold < 0.05 were identified when comparing the ischemic vs. normal tissue from high-fat diet animals. When examining the effect of EV treatment in ischemic tissue in subjects on a normal diet, there were 574 loci with nominal P value < 0.05 with two loci Fructosamine 3 kinase related protein [(FN3KRP) (P < 0.001)] and SNTG1 (P = 0.03) significant after Bonferroni correction. When examining the effect of EV treatment in ischemic tissue in HFD, there were 511 loci with nominal P values < 0.05. After Bonferroni correction, two loci had P values less than 0.05, betacellulin [(BTC) (P = 0.008)] and [proprotein convertase subtilisin/kexin type 7 (PCSK7) (P = 0.01)]. Conclusions: Alterations in DNA methylation were identified in pig myocardium after ischemic insult, change in diet, and treatment with EVs. Hundreds of differentially methylated loci were detected, but the magnitude of the effects was low. These changes represent significant alterations in DNA methylation and merit further investigation.
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INTRODUCTION: Stroke mimics are a major diagnostic challenge during the initial evaluation of patients presenting with an acute focal neurological deficit. This case reviews a patient who presented to the emergency department (ED) with homonymous hemianopsia, a rare manifestation of focal status epilepticus of the occipital lobe. Her initial brain computed axial tomographic perfusion scan and magnetic resonance imaging revealed novel findings associated with this diagnosis. CASE REPORT: A 70-year-old female presented to our ED with left visual field hemianopsia, dyskinesia, dysmetria, and facial droop. Her initial diagnosis was left posterior fossa circulation cerebrovascular accident. However, her neuroimaging indicated hypervascularity of the left occipital lobe without evidence of infarct or structural lesion. A cerebral angiogram excluded arteriovenous malformation. Subsequently, an electroencephalogram showed left occipital lobe status epilepticus. CONCLUSION: Hemianopsia is a rare presentation of focal status epilepticus mimicking stroke. Hypervascularity seen on advanced neuroimaging may have suggested this diagnosis on initial ED evaluation.
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Countering violent radicalization is a priority in many countries, prompting research that assesses attitudes and beliefs about violent radicalization in the general population. The majority of violent radicalization assessments have been developed among specific populations, with limited investigation into the generalizability and cross-cultural applicability of measurement tools. A transcultural investigation raises questions about the implicit assumptions and norms that inform instrument development. This research examined the psychometric properties of the Sympathy for Violent Radicalization Scale (SyfoR), a measure developed for use with Pakistani and Bangladeshi immigrant groups in the UK, in two convenience samples of youth and young adults in North America and Western Europe. We investigated the factor structure, reliability, and construct validity of adapted versions of the SyfoR among convenience samples of youth and young adults living in Belgium (N = 2014) and in Quebec, Canada (N = 1364) via online surveys administered to students engaged in secondary and post-secondary education. Results indicate that, in both samples, a reduced, 8-item version of the SyfoR has a 3-factor structure with good model fit statistics using confirmatory factor analysis and good internal consistency reliability. More studies are needed to assess the appropriateness of the SyfoR for use in diverse contexts and among diverse populations. The potential usefulness and harmfulness of measures of violent radicalization should balance the benefits of obtaining local data with the risks associated with pathologizing social dissent.
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Agresión , Violencia , Adolescente , Actitud , Humanos , Psicometría , Reproducibilidad de los Resultados , Encuestas y Cuestionarios , Adulto JovenRESUMEN
Background. Highly processed foods are inexpensive and abundant in our food supply, nutritionally poor, and disproportionately marketed to minority youth. This study is part of a curriculum development project to develop, implement, and evaluate the In Defense of Food (IDOF) curriculum designed to increase intake of whole/minimally processed foods and decrease intake of highly processed foods in youth. Aims. This pilot outcome evaluation was undertaken to assess initial effectiveness and to provide an in-depth understanding of changes in behavioral outcomes and psychosocial mediators. Methods. We used an explanatory mixed method approach, including a single-arm pretest-posttest of intervention effect, followed by a food rules assessment and in-depth interviews to describe participant responses to the intervention in more detail. The study was conducted in three afterschool classrooms in urban low-income neighborhoods with 32 multiethnic middle-school youth, receiving 10 weekly 2-hour sessions. Results. Two weeks postintervention, there was a large positive significant increase in whole/minimally processed food intake (p < .01; d = 0.59) and a small decrease in consumption of highly-processed foods (p = ns; d = 0.06), compared with baseline. Significant increases in psychosocial mediators: Self-efficacy and positive outcomes expectations were seen; others were not significant but changed in the desired direction. Qualitative assessments suggest that the intervention promoted skill building, but environmental barriers made these difficult to use. Discussion. The IDOF curriculum may be most effective for promoting consumption of fruits and vegetables, rather than decreasing intake of highly processed foods. In addition, in this young age-group, short actionable food rules may support self-regulation and behavior change. Conclusion. Among adolescent students in low-income urban neighborhoods, the IDOF afterschool curriculum may help promote self-efficacy and positive outcome expectancies and increase fruit and vegetable intake. Focusing on food processing and using "Food Rules" may be promising to elicit behavior change in youth; however, greater supports are needed to overcome social and environmental barriers.