The Policy Research Working Paper Series disseminates the findings of work in progress to encourage the exchange of ideas about development issues. An objective of the series is to get the findings out quickly, even if the presentations are less than fully polished. The papers carry the names of the authors and should be cited accordingly. The findings, interpretations, and conclusions expressed in this paper are entirely those of the authors. They do not necessarily represent the views of the International Bank for Reconstruction and Development/World Bank and its affiliated organizations, or those of the Executive Directors of the World Bank or the governments they represent.
The assessment of flow velocity (FV) in the left atrial appendage (LAA) by transesophageal echocardiography (TEE) has been reported to be a useful tool as a high risk marker for systemic emboli. The analysis of FV in LAA by transthoracic echocardiography (TTE) has not yet been validated. The purpose of this study was to compare FV measurements in the LAA by TEE and TTE in 30 consecutive patients (age 19-87 years, mean = 55) sent for echocardiographic study with the following diagnosis: stroke (11 patients), mitral stenosis (6 patients), congenital heart disease (4 patients), mitral prosthetic function assessment (2 patients), and other pathologies (7 patients). FV was measured at the outlet and mid-portion of the LAA with TTE, from the apical two-chamber view and with biplane TEE, from the longitudinal two-chamber view. Satisfactory measurements were obtained with TTE from the outlet of the LAA in 96.7% and from the mid-portion of the LAA in 90% of patients. One third of patients were in atrial fibrillation (AF) during the study. The mean FV in the outlet of the LAA was 32.7 +/- 2.5 (SE) cm/sec with TTE and was 33.7 +/- 3.04 (SE) cm/sec with TEE (r = 0.95). The mean FV in the mid-portion of the LAA was 40.9 +/- 3.3 and 42.7 +/- 3.9 with TTE and TEE respectively (P = NS) (r = 0.95). There was no difference in the LAA FV determination by TTE and TEE in the subgroup with AF. TTE was able to detect FV < 30 cm/sec with a sensitivity of 88% and specificity of 81% and a positive predictive value of 84% compared with TEE.
Lope Hugo Barrero ** Leonardo a. Quintana *** aLfonso sáncHez **** aLejandro forero ***** juLián Quiroga ****** Pontificia Universidad Javeriana, Bogotá saraH feLknor ******* University of Texas, Houston, Texas, United States a B s t r a c t Understanding the pedestrian choices is essential for the design of safe road systems. This study develops methods for self-reported assessment of pedestrian behavior. A self-report instrument was developed to investigate the Theory of Planned Behavior (TPB) constructs in relation to pedestrians' road crossing using a convenient sample. Internal consistency and factor analysis were conducted to test the reliability and construct validity of the instrument. Self-reported intention to execute risky behavior was compared with observed behaviors. The developed questionnaire showed high internal consistency for most of the TPB constructs (Chronbach's alpha>0.7). Factor analyses confirmed that questions grouped in constructs, as hypothesized. Pedestrians' intention to execute risky behavior was related to pedestrians' perceived physical capability and to the simultaneous crossing of other pedestrians. However, this intention correlated moderately with observed risky behavior (R s =0.35). The potential to understand the mechanisms of pedestrian choices using the developed instrument are considered exploratory, yet promising. r e s u m e n El poder entender las decisiones que toma un peatón es esencial para el diseño de sistemas viales seguros. Este estudio desarrolla métodos para la medición del comportamiento del peatón por medio de auto-reportes. Se desarrolló un instrumento de auto-reporte para investigar los constructos de la Teoría del Comportamiento Planeado (TPB, por sus siglas en inglés) en relación al cruce de las vías por parte de los peatones, usando una muestra conveniente. Se condujeron análisis de consistencia interna y de factores para probar la confiabilidad y validez de constructos del instrumento. La intención auto-reportada de ejecutar comportamientos riesgosos fue comparada con los comportamientos observados. El desarrollo del cuestionario mostró una alta consistencia interna para la mayoría de los constructos del TPB (alfa de Cronbach > 0.7). El análisis de factores confirmó que las preguntas se agrupaban en constructos, tal y como se hipotetizó; la intención de los peatones de ejecutar comportamientos riesgosos estuvo relacionada con Key words authors
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