Loading...
Search for:
longitudinal-data
0.007 seconds
Single-replicate longitudinal data analysis in the presence of multiple instrumental measurement errors
, Article Computers and Industrial Engineering ; Volume 141 , 2020 ; Behbahani, M ; Khedmati, M ; Akhavan Niaki, S. T ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
In this paper, a novel method as a combination of the expectation–maximization (EM) algorithm and Variogram is proposed to decompose the longitudinal measurement errors in the absence of replications and the presence of multiple instrumental measurement errors. In the proposed method, multiple measurements are considered where the units are observed by several distinct instruments (gauges). The approach decouples the observed variance of the measurement model into the process and measurement system variances. In addition, it decomposes the variance of multiple instruments into the process and instrument variances. In the end, the proposed model is validated and tested based on simulated...
Electrocardiographic ST-segment depression and exposure to traffic-related aerosols in elderly subjects with coronary artery disease
, Article Environmental Health Perspectives ; Volume 119, Issue 2 , Feb , 2011 , Pages 196-202 ; 00916765 (ISSN) ; Gillen, D. L ; Tjoa, T ; Staimer, N ; Polidori, A ; Arhami, M ; Sioutas, C ; Longhurst, J ; Sharif University of Technology
2011
Abstract
Background: Air pollutants have not been associated with ambulatory electrocardiographic evidence of ST-segment depression ≥ 1 mm (probable cardiac ischemia). We previously found that markers of primary (combustion-related) organic aerosols and gases were positively associated with circulating biomarkers of inflammation and ambulatory blood pressure in the present cohort panel study of elderly subjects with coronary artery disease. Objectives: We specifically aimed to evaluate whether exposure markers of primary organic aerosols and ultrafine particles were more strongly associated with ST-segment depression of ≥ 1 mm than were secondary organic aerosols or PM 2.5 (particulate matter with...
Association of biomarkers of systemic inflammation with organic components and source tracers in quasi-ultrafine particles
, Article Environmental Health Perspectives ; Volume 118, Issue 6 , 2010 , Pages 756-762 ; 00916765 (ISSN) ; Staimer, N ; Tjoa, T ; Arhami, M ; Polidori, A ; Gillen, D. L ; Kleinman, M. T ; Schauer, J. J ; Sioutas, C ; Sharif University of Technology
2010
Abstract
Background: Evidence is needed regarding the air pollutant components and their sources responsible for associations between particle mass concentrations and human cardiovascular outcomes. We previously found associations between circulating biomarkers of inflammation and mass concentrations of quasi-ultrafine particles ≤ 0.25 μm in aerodynamic diameter (PM0.25) in a panel cohort study of 60 elderly subjects with coronary artery disease living in the Los Angeles Basin.Objectives: We reassessed biomarker associations with PM0.25 using new particle composition data.Methods: Weekly biomarkers of inflammation were plasma interleukin-6 (IL-6) and soluble tumor necrosis factor-α receptor II...