The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
J E Myers - One of the best experts on this subject based on the ideXlab platform.
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tuberculosis and silica exposure in south african gold miners
Occupational and Environmental Medicine, 2006Co-Authors: Jim Tewaternaude, Rodney Ehrlich, Gavin J Churchyard, L Pemba, K Dekker, N W White, M Vermeis, Mary Lou Thompson, J E MyersAbstract:Aims: To examine the effect of silica exposure, in the absence of silicosis, on the prevalence of pulmonary tuberculosis (PTB), which is epidemic among South African gold miners. Methods: Cross-sectional study of 520 gold miners over 37 years of age. Length of Service, and cumulative and average dust and quartz exposure indices were derived for each miner. Chest radiographs were read for PTB by two NIOSH “B” readers. PTB was defined as a self-reported history of PTB or PTB on chest radiograph. Logistic regression was used to adjust for age, smoking, and silicosis. PTB effects of different exposure metrics for silica, scaled on their interquartile range (IQR), were compared. Results: Means (ranges) were: age 46.7 (37.1–59.9) years; Length of Service 21.8 (6.3–34.5) years; average intensity of respirable quartz 0.053 (0–0.095) mg/m 3 . PTB prevalence was 19.4% (95% CI 16.0 to 22.8) on history alone, and 35.2% (95% CI 31.1 to 39.3) on history or on chest radiograph. Length of Service was poorly predictive of PTB, while all exposure indices which included dust or quartz yielded prevalence odds ratios (PORs) of approximately 1.4 (95% CI ∼1.1 to 1.8) for changes of one interquartile range in exposure. Controlling for silicosis—by adjustment or restriction—did not modify these results. Drillers and winch operators had the highest PTB prevalences and the highest dust and silica exposures. Conclusion: Older in-Service gold miners in South Africa have a high prevalence of PTB, which is significantly associated with dust and silica exposure, even in the absence of silicosis. Limitations include a survivor workforce and the use of cumulative exposures based on current exposures. Dust control is an important component in control of the PTB epidemic in South African gold mines.
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silicosis prevalence and exposure response relations in south african goldminers
Occupational and Environmental Medicine, 2004Co-Authors: Gavin J Churchyard, Rodney Ehrlich, Jim Tewaternaude, L Pemba, K Dekker, M Vermeijs, N W White, J E MyersAbstract:Aims: To measure the prevalence of silicosis among black migrant contract workers on a South African goldmine and to investigate exposure-response relations with silica dust. Methods: In a cross sectional study, 520 black goldminers (aged >37 years) were interviewed and had chest radiographs taken. Silicosis was defined as International Labour Organisation Classification radiological profusion of 1/1 or greater. Results: Mean Length of Service was 21.8 years (range 6.3–34.5). The mean intensity of respirable dust exposure was 0.37 mg/m3 (range 0–0.70) and of quartz 0.053 mg/m3 (range 0–0.095). The prevalence of silicosis was 18.3–19.9% depending on reader. Significant trends were found between the prevalence of silicosis and Length of Service, mean intensity of exposure, and cumulative exposure. Conclusion: Results confirm a large burden of silicosis among older black workers in the South African goldmining industry, which is likely to worsen as such miners spend longer periods in continuous employment in dusty jobs. An urgent need for improved dust control in the industry is indicated. If the assumption of stability of average dust concentrations on this mine over the working life of this group of workers is correct, these workers developed silicosis while exposed to a quartz concentration below the recommended occupational exposure limit (OEL) of 0.1 mg/m3. This accords with a mounting body of evidence that an OEL of 0.1 mg/m3 is not protective against silicosis.
J Z Shao - One of the best experts on this subject based on the ideXlab platform.
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correlation of job monotony and social support on daily hassle a cross sectional study based on natural gas field workers
Chinese Journal of Preventive Medicine, 2020Co-Authors: Weimin Zhou, J Z ShaoAbstract:Objective: To explore the correlation of job monotony and social support on daily hassle. Methods: A convenient sampling survey of demographics characteristics, job monotony, social support and daily hassle was conducted on 1 466 natural gas field workers by questionnaire in October; 2018. Multivariate logistic regression model was used to analyze the correlation of job monotony and social support on daily hassle. Results: The age of 1 466 subjects was (44.47±8.0) years and the Length of Service was (20.46±5.77) years. There were 258(17.6%), 173(11.8%), 799(54.5%), 120(8.2%) and 116(7.9%) subjects from production and marketing department, processing plant, branch, maintenance department and emergency center respectively. There were 374(25.5%) and 1 092(74.5%) subjects with high and low level of job monotony, and 398(27.1%), 648(44.2%) and 420(28.6%) subjects with high, middle and low level of social support. There were 464(31.7%) and 1 002(68.3%) subjects with high and low daily tension respectively. Compared with the low level of job monotony, the high level of job monotony had a higher risk of daily hassle(OR=4.83,P<0.001), and compared with the high level of social support, the middle and low level of social support had a higher risk of daily hassle(OR=1.25, 2.24,P<0.05). Conclusion: Job monotony and social support were associated with daily hassle.
Carla M Flink - One of the best experts on this subject based on the ideXlab platform.
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experience counts the chief justice management tenure and strategic behavior on the u s supreme court
Research & Politics, 2016Co-Authors: Carla M FlinkAbstract:We develop and test a theoretical account of the effect of management tenure on the strategic behavior of the chief justice of the United States. Substantial evidence from literatures on learning models and public management indicate that tenure (Length of Service) is positively related to management performance in public organizations. This suggests that the chief justice’s tenure in office should be positively related to efficiency in the use of the chief justice’s formal powers. We assess this hypothesis by replicating and extending Johnson et al.’s study of chief justice Burger’s conference voting behavior. The data support our management tenure hypothesis, showing that Burger used greater discretion in reserving his conference vote over time as he became more adept at discriminating between circumstances when the tactic was strategically valuable and when it was not.
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the chief justice experience and strategic behavior on the supreme court
Social Science Research Network, 2016Co-Authors: Carla M FlinkAbstract:We develop and test a theoretical account of the effect of management tenure on the strategic behavior of the Chief Justice of the United States. Substantial evidence from a variety of learning models and the public management literature indicates that tenure (Length of Service) is positively related to management performance in public organizations. This suggests that the chief justice’s tenure in office should be positively related to efficiency in the use of the chief justice’s formal powers. We assess this hypothesis by replicating and extending Johnson, Spriggs, and Wahlbeck’s (2005) study of Chief Justice Burger’s conference voting behavior. The data support our management tenure hypothesis, showing that Burger used greater discretion in reserving his conference vote over time as he became more adept at discriminating between circumstances when the tactic was strategically valuable and when it was not.
Gavin J Churchyard - One of the best experts on this subject based on the ideXlab platform.
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tuberculosis and silica exposure in south african gold miners
Occupational and Environmental Medicine, 2006Co-Authors: Jim Tewaternaude, Rodney Ehrlich, Gavin J Churchyard, L Pemba, K Dekker, N W White, M Vermeis, Mary Lou Thompson, J E MyersAbstract:Aims: To examine the effect of silica exposure, in the absence of silicosis, on the prevalence of pulmonary tuberculosis (PTB), which is epidemic among South African gold miners. Methods: Cross-sectional study of 520 gold miners over 37 years of age. Length of Service, and cumulative and average dust and quartz exposure indices were derived for each miner. Chest radiographs were read for PTB by two NIOSH “B” readers. PTB was defined as a self-reported history of PTB or PTB on chest radiograph. Logistic regression was used to adjust for age, smoking, and silicosis. PTB effects of different exposure metrics for silica, scaled on their interquartile range (IQR), were compared. Results: Means (ranges) were: age 46.7 (37.1–59.9) years; Length of Service 21.8 (6.3–34.5) years; average intensity of respirable quartz 0.053 (0–0.095) mg/m 3 . PTB prevalence was 19.4% (95% CI 16.0 to 22.8) on history alone, and 35.2% (95% CI 31.1 to 39.3) on history or on chest radiograph. Length of Service was poorly predictive of PTB, while all exposure indices which included dust or quartz yielded prevalence odds ratios (PORs) of approximately 1.4 (95% CI ∼1.1 to 1.8) for changes of one interquartile range in exposure. Controlling for silicosis—by adjustment or restriction—did not modify these results. Drillers and winch operators had the highest PTB prevalences and the highest dust and silica exposures. Conclusion: Older in-Service gold miners in South Africa have a high prevalence of PTB, which is significantly associated with dust and silica exposure, even in the absence of silicosis. Limitations include a survivor workforce and the use of cumulative exposures based on current exposures. Dust control is an important component in control of the PTB epidemic in South African gold mines.
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silicosis prevalence and exposure response relations in south african goldminers
Occupational and Environmental Medicine, 2004Co-Authors: Gavin J Churchyard, Rodney Ehrlich, Jim Tewaternaude, L Pemba, K Dekker, M Vermeijs, N W White, J E MyersAbstract:Aims: To measure the prevalence of silicosis among black migrant contract workers on a South African goldmine and to investigate exposure-response relations with silica dust. Methods: In a cross sectional study, 520 black goldminers (aged >37 years) were interviewed and had chest radiographs taken. Silicosis was defined as International Labour Organisation Classification radiological profusion of 1/1 or greater. Results: Mean Length of Service was 21.8 years (range 6.3–34.5). The mean intensity of respirable dust exposure was 0.37 mg/m3 (range 0–0.70) and of quartz 0.053 mg/m3 (range 0–0.095). The prevalence of silicosis was 18.3–19.9% depending on reader. Significant trends were found between the prevalence of silicosis and Length of Service, mean intensity of exposure, and cumulative exposure. Conclusion: Results confirm a large burden of silicosis among older black workers in the South African goldmining industry, which is likely to worsen as such miners spend longer periods in continuous employment in dusty jobs. An urgent need for improved dust control in the industry is indicated. If the assumption of stability of average dust concentrations on this mine over the working life of this group of workers is correct, these workers developed silicosis while exposed to a quartz concentration below the recommended occupational exposure limit (OEL) of 0.1 mg/m3. This accords with a mounting body of evidence that an OEL of 0.1 mg/m3 is not protective against silicosis.
Jim Tewaternaude - One of the best experts on this subject based on the ideXlab platform.
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tuberculosis and silica exposure in south african gold miners
Occupational and Environmental Medicine, 2006Co-Authors: Jim Tewaternaude, Rodney Ehrlich, Gavin J Churchyard, L Pemba, K Dekker, N W White, M Vermeis, Mary Lou Thompson, J E MyersAbstract:Aims: To examine the effect of silica exposure, in the absence of silicosis, on the prevalence of pulmonary tuberculosis (PTB), which is epidemic among South African gold miners. Methods: Cross-sectional study of 520 gold miners over 37 years of age. Length of Service, and cumulative and average dust and quartz exposure indices were derived for each miner. Chest radiographs were read for PTB by two NIOSH “B” readers. PTB was defined as a self-reported history of PTB or PTB on chest radiograph. Logistic regression was used to adjust for age, smoking, and silicosis. PTB effects of different exposure metrics for silica, scaled on their interquartile range (IQR), were compared. Results: Means (ranges) were: age 46.7 (37.1–59.9) years; Length of Service 21.8 (6.3–34.5) years; average intensity of respirable quartz 0.053 (0–0.095) mg/m 3 . PTB prevalence was 19.4% (95% CI 16.0 to 22.8) on history alone, and 35.2% (95% CI 31.1 to 39.3) on history or on chest radiograph. Length of Service was poorly predictive of PTB, while all exposure indices which included dust or quartz yielded prevalence odds ratios (PORs) of approximately 1.4 (95% CI ∼1.1 to 1.8) for changes of one interquartile range in exposure. Controlling for silicosis—by adjustment or restriction—did not modify these results. Drillers and winch operators had the highest PTB prevalences and the highest dust and silica exposures. Conclusion: Older in-Service gold miners in South Africa have a high prevalence of PTB, which is significantly associated with dust and silica exposure, even in the absence of silicosis. Limitations include a survivor workforce and the use of cumulative exposures based on current exposures. Dust control is an important component in control of the PTB epidemic in South African gold mines.
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silicosis prevalence and exposure response relations in south african goldminers
Occupational and Environmental Medicine, 2004Co-Authors: Gavin J Churchyard, Rodney Ehrlich, Jim Tewaternaude, L Pemba, K Dekker, M Vermeijs, N W White, J E MyersAbstract:Aims: To measure the prevalence of silicosis among black migrant contract workers on a South African goldmine and to investigate exposure-response relations with silica dust. Methods: In a cross sectional study, 520 black goldminers (aged >37 years) were interviewed and had chest radiographs taken. Silicosis was defined as International Labour Organisation Classification radiological profusion of 1/1 or greater. Results: Mean Length of Service was 21.8 years (range 6.3–34.5). The mean intensity of respirable dust exposure was 0.37 mg/m3 (range 0–0.70) and of quartz 0.053 mg/m3 (range 0–0.095). The prevalence of silicosis was 18.3–19.9% depending on reader. Significant trends were found between the prevalence of silicosis and Length of Service, mean intensity of exposure, and cumulative exposure. Conclusion: Results confirm a large burden of silicosis among older black workers in the South African goldmining industry, which is likely to worsen as such miners spend longer periods in continuous employment in dusty jobs. An urgent need for improved dust control in the industry is indicated. If the assumption of stability of average dust concentrations on this mine over the working life of this group of workers is correct, these workers developed silicosis while exposed to a quartz concentration below the recommended occupational exposure limit (OEL) of 0.1 mg/m3. This accords with a mounting body of evidence that an OEL of 0.1 mg/m3 is not protective against silicosis.