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1.
Associations between increased job control and health status were tested with questionnaire data from a random sample of full-time workers (n = 8504) from the national Swedish white collar labor federation, TCO (representing 25 per cent of the Swedish work force). Of these subjects, 1937 had undergone a company-initiated job reorganization during the previous several years. Workers in the job reorganization group who had influence in the reorganization process and obtained increased task control as a result had lower levels of illness symptoms on 11 of 12 health indicators controlling for age and sex (11 of 12 associations significant for males, four of 12 associations significant for females). A previously validated measure of coronary heart disease was significantly lower in circumstances of increased job control for males (8.6 per cent symptom frequency with decreased control versus 3.4 per cent with increased control; p = 0.05). Absenteeism was lower: 10.7 per cent versus 5.0 per cent (0.01). Depression was lower 27.8 per cent to 13.7 per cent (0.001). However, smoking was significantly higher for women 11.0 per cent versus 23.5 per cent (0.01). All illness indicators showed that the process of job reorganization itself was associated with significantly higher symptoms (‘change stress’). However for males (only) symptoms levels when reorganization was accompanied by increased control were often as low or lower than symptom levels for no reorganization at all. Unfortunately, job reorganizations involving employee influence and increased task control were less frequent than job reorganizations involving reduced influence and no increased control, especially for women and older workers.  相似文献   

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This study analyzes 46 brain and 48 spinal-cord impact experiments. The velocity of brain impact was 2.0-10.0 m/s and displacement, 0.75-5.0 mm (5.3-33% compression) using a controlled pneumatic impact. The velocity of spinal-cord impact was 1.5-6.0 m/s and displacement, 1.25-3.25 mm (25-65% compression). Brain injury varied from cortical contusion, diffuse axonal injury (DAI), to fatalities, and spinal-cord injury from temporary to complete loss of somatosensory-evoked potentials. Logist functions were determined for each injury severity and various biomechanical parameters, VC, C, V, and combinations. Brain and spinal-cord injury is most strongly correlated to VC, the viscous response. The goodness-of-fit was x2 = 22.1, R-0.84 and p< 0.0000 for fatal brain injury, x2 = 27.5, R = 0.96 and p< 0.0000 for cortical contusion, and x2 = 17.7, R = 0.49 and p < 0.0001 for partial recovery of spinal-cord conduction. Neural tissue is viscoelastic, with a rate-dependent tolerance related to energy absorption. VC is a measure of energy absorption by impact deformation and is predictive of neural contusion, DAI, long-duration coma, spinal-cord dysfunction, and death. Tolerances for various severities of neural injury are presented. At the tissue level, VC is the product of strain and strain-rate, ε dε/dt. The research shows that strain is not a sufficient parameter of neural injury risk, and that the product of strain and strain-rate is a key biomechanical parameter for brain and spinal-cord injury.  相似文献   

4.
This study uses an interactionist approach to examine the moderating effect of follower trait positive affectivity (trait PA) on the relation between transformational leadership and both follower creative performance and organizational citizenship behaviors (OCB). On the basis of responses from 212 employees and their direct supervisors from the research and development department of a company in Mainland China, results support the hypothesized moderation effect. Specifically, the positive influence of transformational leadership on creative performance was significantly reduced for followers who were higher on trait PA (ΔR2 = .02, p < .05). The same pattern, in which followers' trait PA appeared to substitute for the influence of transformational leadership, generalized to the outcome of follower OCB as well (ΔR2 = .04, p < .01). We discussed theoretical and practical implications of these findings. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

5.
Objectives: The objective of the study is to determine whether specific child restraint system (CRS) or vehicle conditions improve top tether attachment rates during volunteer installations.

Methods: A factorial randomized controlled trial was designed to evaluate 4 different experimental categories: (1) Color of tether adjuster casing (black or red), (2) labeling on tether adjuster casing (labeled with “Tether: Use for forward-facing” or unlabeled), (3) storage location of tether (bundled in a rubber band on the back of CRS or Velcroed over the forward-facing belt path), and (4) labeling in vehicle (labeled under head restraint and below anchor or unlabeled). Ninety-six volunteers were randomly assigned to one combination of conditions. One installation per volunteer was completed. The primary outcome measure was acceptable attachment of the top tether to the tether anchor. The secondary outcome measure was overall secureness of the installation. Pearson’s chi-square tests were used to identify significant predictors of acceptable outcomes and logistic regression was used to investigate interaction effects.

Results: A total of 66/96 subjects (68.8%) attached the top tether in an acceptable manner, with either zero errors (n?=?50) or minor errors (n?=?16). A total of 30/96 subjects (31.2%) had unacceptable tether outcomes, with either major errors (n?=?10) or nonuse the tether at all (n?=?20). None of the 4 experimental categories significantly affected tether outcomes. Subjects who opted to install the CRS with the lower anchors (LAs) had higher rates of acceptable tether attachment compared to subjects who installed using the seat belt or those who used both LA and seat belt together (χ2 = 6.792, P = .034). Tether outcomes were not correlated with previous CRS experience, use of instruction manual(s), age, or sex. Only 15.6% of subjects produced overall correct and tight installations. Of those who used the seat belt in some manner, 70.2% neglected to switch the retractor into locking mode.

Conclusions: Conditions in this study including tether color, tether labeling, storage location, and vehicle labeling did not significantly affect tether attachment rates. High rates of tether misuse and nonuse warrant further exploration to find effective solutions to this usability problem.  相似文献   

6.
Objective: The goal of this study was to investigate the influence of the occupant characteristics on seat belt force vs. payout behavior based on experiment data from different configurations in frontal impacts.

Methods: The data set reviewed consists of 58 frontal sled tests using several anthropomorphic test devices (ATDs) and postmortem human subjects (PMHS), restrained by different belt systems (standard belt, SB; force-limiting belt, FLB) at 2 impact severities (48 and 29 km/h). The seat belt behavior was characterized in terms of the shoulder belt force vs. belt payout behavior. A univariate linear regression was used to assess the factor significance of the occupant body mass or stature on the peak tension force and gross belt payout.

Results: With the SB, the seat belt behavior obtained by the ATDs exhibited similar force slopes regardless of the occupant size and impact severities, whereas those obtained by the PMHS were varied. Under the 48 km/h impact, the peak tension force and gross belt payout obtained by ATDs was highly correlated to the occupant stature (P =.03, P =.02) and body mass (P =.05, P =.04), though no statistical difference with the stature or body mass were noticed for the PMHS (peak force: P =.09, P =.42; gross payout: P =.40, P =.48). With the FLB under the 48 km/h impact, highly linear relationships were noticed between the occupant body mass and the peak tension force (R2 = 0.9782) and between the gross payout and stature (R2 = 0.9232) regardless of the occupant types.

Conclusions: The analysis indicated that the PMHS characteristics showed a significant influence on the belt response, whereas the belt response obtained with the ATDs was more reproducible. The potential cause included the occupant anthropometry, body mass distribution, and relative motion among body segments specific to the population variance. This study provided a primary data source to understand the biomechanical interaction of the occupant with the restraint system. Further research is necessary to consider these effects in the computational studies and optimized design of the restraint system in a more realistic manner.  相似文献   


7.
This study focuses on burnout and its positive antipode—engagement. A model is tested in which burnout and engagement have different predictors and different possible consequences. Structural equation modeling was used to simultaneously analyze data from four independent occupational samples (total N = 1698). Results confirm the hypothesized model indicating that: (1) burnout and engagement are negatively related, sharing between 10 per cent and 25 per cent of their variances; (2) burnout is mainly predicted by job demands but also by lack of job resources, whereas engagement is exclusively predicted by available job resources; (3) burnout is related to health problems as well as to turnover intention, whereas engagement is related only to the latter; (4) burnout mediates the relationship between job demands and health problems, whereas engagement mediates the relationship between job resources and turnover intention. The fact that burnout and engagement exhibit different patterns of possible causes and consequences implies that different intervention strategies should be used when burnout is to be reduced or engagement is to be enhanced. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   

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The objective of this research is to evaluate all the critical reaches in a cockpit and determine the visual sufficiency of a cockpit to accommodate 90% of potential pilots. While mismatches of measurements with cockpit dimensions are revealed, proposals are made to improve cockpit ergonomics. Regression models were generated to predict and assure adequate exterior vision. Mean, lower and upper control limits of all measurements were found acceptable except eye level. There are very strong positive relationships between stature and eye level (R2?=?0.972, p?R2?=?0.994, p?SD smaller than the eye level mean or seating adjustment limits in height may be changed. In general, cockpit design is acceptable in terms of fit/reach accommodation for pilots, except eye level and visual variables that could be solved by better seat adjustments.  相似文献   

10.
The aim of the study was to compare the performances of the Brungraber Mark II (BM II) and Mark III (BM III) slipmeters. Friction measurements with the two slipmeters were conducted in a laboratory using four footwear materials, four floor types, and three surface conditions. Both the coefficient of friction (COF) values obtained with the slipmeters and the force platform-based COF values were measured. The COF measured with the BM II was slightly higher than that measured with the BM III with a R2 of 0.83. A comparison of the averaged normal force between the two slipmeters showed that the BM II generated a significantly higher normal force than the BM III at a low COF and the difference of the normal force between the two slipmeters decreased when the COF value was increased. The regression analysis results in this study showed that the force platform-based COF values were closer to the COF values obtained with the BM III than with the BM II. The R2 values for the regression model between the COF values obtained from the slipmeter and the force platform were 0.90 and 0.79 for the BM II and BM III, respectively.  相似文献   

11.
Objectives: In this study, we aimed to determine whether three minimum legal drinking age 21 (MLDA-21) laws—dram shop liability, responsible beverage service (RBS) training, and state control of alcohol sales—have had an impact on underage drinking and driving fatal crashes using annual state-level data, and compared states with strong laws to those with weak laws to examine their effect on beer consumption and fatal crash ratios.

Methods: Using the Fatality Analysis Reporting System, we calculated the ratio of drinking to nondrinking drivers under age 21 involved in fatal crashes as our key outcome measure. We used structural equation modeling to evaluate the three MLDA-21 laws. We controlled for covariates known to impact fatal crashes including: 17 additional MLDA-21 laws; administrative license revocation; blood alcohol concentration limits of.08 and.10 for driving; seat belt laws; sobriety checkpoint frequency; unemployment rates; and vehicle miles traveled. Outcome variables, in addition to the fatal crash ratios of drinking to nondrinking drivers under age 21 included state per capita beer consumption.

Results: Dram shop liability laws were associated with a 2.4% total effect decrease (direct effects: β =.019, p =.018). Similarly, RBS training laws were associated with a 3.6% total effect decrease (direct effect: β =.048, p =.001) in the ratio of drinking to nondrinking drivers under age 21 involved in fatal crashes. There was a significant relationship between dram shop liability law strength and per capita beer consumption, F (4, 1528) = 24.32, p <.001, partial η2 =.016, showing states with strong dram shop liability laws (Mean (M) = 1.276) averaging significantly lower per capita beer consumption than states with weak laws (M = 1.340).

Conclusions: Dram shop liability laws and RBS laws were both associated with significantly reduced per capita beer consumption and fatal crash ratios. In practical terms, this means that dram shop liability laws are currently associated with saving an estimated 64 lives in the 45 jurisdictions that currently have the law. If the remaining 6 states adopted the dram shop law, an additional 9 lives could potentially be saved annually. Similarly, RBS training laws are associated with saving an estimated 83 lives in the 37 jurisdictions that currently have the laws. If the remaining 14 states adopted these RBS training laws, we estimate that an additional 28 lives could potentially be saved.  相似文献   

12.
This study was conducted to determine the most appropriate surface processing techniques (SPT), environmental conditions (EC) and surface roughness (SR) to minimize the risk of slipping when pedestrians walk on a floor covering of rocks barefoot and with shoes. Coefficients of friction (COFs) and values of SR were found using five different types of rocks, four SPT and two (ramp and pendulum) tests. Results indicate that the parameters which affect the COF values of rocks include SR, EC and SPT. Simple linear regression was performed to examine the relationship between the values of the COF and the SR. The value of the COF was identified as R2?≥?0.864. Statistical results, which are based on experimental measurements, show that rocks are classified according to their safe use areas depending on their COF and SR values.  相似文献   

13.
The purpose of this study was to investigate the applicability of the Schmidt–Hunter global estimation method of assessing utility across a broad range of jobs. Ninety-five industrial/organizational psychologists estimated the utility of performance in 24 carefully selected jobs. The utility estimates were compared to the Data, People, and Things worker function parameters from the Dictionary of Occupational Titles. The majority of jobs (62.5 per cent) produced significantly positively skewed distributions of dollar-valued job performance. The Data, People, and Things parameters accounted for 46 per cent of the variance in the non-symmetry of the utility distributions and 33 per cent of the variance in the inter-rater reliability of the utility estimates. The implications of the results were discussed for utility assessment, and explained from a decision theoretic perspective. © 1998 John Wiley & Sons, Ltd.  相似文献   

14.
The occurrence and impact of psychological contract violations were studied among graduate management alumni (N = 128) who were surveyed twice, once at graduation (immediately following recruitment) and then two years later. Psychological contracts, reciprocal obligations in employment developed during and after recruitment, were reported by a majority of respondents (54.8 per cent) as having been violated by their employers. The impact of violations are examined using both quantitative and qualitative data. Occurrence of violations correlated positively with turnover and negatively with trust, satisfaction and intentions to remain.  相似文献   

15.
Objective: The objective of this study was to conduct a comprehensive analysis of demographics, injury characteristics and hospital resource utilization of significant pediatric electric bicycle (e-bike) injuries leading to hospitalization following an emergency department visit in comparison to pediatric injuries caused by other traffic related mechanisms.

Methods: A retrospective review of all pediatric traffic injury hospitalizations following an emergency department visit to a level I trauma center between October 2014 and September 2016 was conducted. Data regarding age, sex, number of computed tomography (CT) scans obtained, number of major procedures, length of hospital stay (LOS), Injury Severity Score (ISS), and number of injuries per patient were collected and compared between e-bike injuries and other traffic injuries.

Results: Three hundred thirty-seven admissions were analyzed: 46 (14%) were due to e-bike injuries (29% of patients >12 years). Age, proportion of brain injuries, and use of CT were significantly increased compared to mechanical bicycle injuries (13.1?±?3.4 vs. 10.6?±?3.6, 13% vs. 3%, 1 [0–3] vs. 1 [0–1], P < .01, P = .03, P = .05). Age, LOS, and use of CT were significantly increased compared to injuries caused to automobile passengers (13.1?±?3.4 vs. 7.4?±?5.3, 1 [1–3] vs. 1 [1–2], 1 [0–3] vs. 0 [0–1], P < .01, P = .03, P = .01), as well as ISS and number of injuries per patient (P = .04, P < .01). Injuries caused by e-bikes were similar to injuries caused to pedestrians, except for age (13.1?±?3.4 vs. 8.5?±?3.7, P < .01). Multivariable analysis revealed a significant association between mechanism of injury and ISS, with increased ISS among e-bike injuries compared to mecahnical bike injuries (OR 2.56, CI 1.1–5.88, P = 0.03) and automobile injuries (OR 4.16, CI 1.49–12.5, (P < .01).

Conclusion: E-bikes are a significant cause of severe injury in children compared to most other traffic injuries, particularly in older children.  相似文献   

16.
The main aim of the study was to propose a model for predicting the peak expiratory flow rate (PEFR) of Nigerian workers in a cement factory. Sixty randomly selected non-smoker and healthy workers (30 in production sections, 30 in the administrative section of the factory) participated in the study. Their physical characteristics and PEFR were measured. Multiple correlations using SPSS version 16.0 were performed on the data. The values of PEFR, using the obtained model, were compared with the measured values using a two-tailed t test. There were positive correlations among age, height and PEFR. A prediction equation for PEFR based on age, height, weight and years of exposure (experience) was obtained with R2?=?.843 (p?<?0.001). The developed model will be useful for the management in determining PEFR of workers in the cement industry for possible medical attention.  相似文献   

17.
Objective: Low bone quality is a contributing factor to motor vehicle crash (MVC) injury. Quantification of occupant bone mineral density (BMD) is important from an injury causation standpoint. The first aim of this study was to validate a technique for measuring lumbar volumetric BMD (vBMD) from phantomless computed tomography (CT) scans. The second aim was to apply the validated phantomless technique to quantify lumbar vBMD in Crash Injury Research and Engineering Network (CIREN) occupants for correlation with age, fracture incidence, and osteopenia/osteoporosis diagnoses.

Methods: Quantitative CT (qCT) and dual-energy X-ray absorptiometry (DXA) were collected prospectively for 50 subjects and used to validate a technique to measure vBMD from 281 phantomless CT scans of CIREN occupants. Hounsfield unit (HU) measurements were collected from the L1–L5 vertebrae, right psoas major muscle, and anterior subcutaneous fat for all subjects and from 3 phantom ports with known mg/cc calcium hydroxyapatite values for the validation group. qCT calibration was accomplished using regressions between the phantom HU and mg/cc values to convert L1–L5 HU values to mg/cc. A phantomless calibration technique was developed where the fat and muscle HU values were linearly regressed against fat (?69 mg/cc) and muscle (77 mg/cc) to establish a conversion for L1–L5 HU measurements to mg/cc. vBMD calculated from qCT versus the phantomless method was compared for the 50 subjects to assess agreement and a mg/cc osteopenia threshold was established using DXA T-scores. CIREN HU measurements were converted to mg/cc using the phantomless technique and the mg/cc osteopenia threshold was used to compare vBMD to age, fracture incidence, and osteopenia comorbidity classifications in CIREN.

Results: Linear regression of lumbar vBMD derived from the qCT versus phantomless calibrations showed excellent agreement (R2 = 0.87, P <.0001). A 145 mg/cc threshold for osteopenia was established (sensitivity = 1, specificity = 0.57) and 44 CIREN occupants had vBMD below this threshold. Of these 44 occupants, 64% were not classified as osteopenic in CIREN, but vBMD suggested undiagnosed osteopenia. Age was negatively correlated with vBMD in both sexes (P <.0001) and CIREN occupants with less than 145 mg/cc vBMD sustained an average 1.7 additional rib/sternum fractures (P =.036).

Conclusions: Because lumbar vBMD was estimated from phantomless CT scans with accuracy similar to qCT, the phantomless technique can be broadly applied to both prospectively and retrospectively assess patient bone quality for research and clinical studies related to MVCs, falls, and aging.  相似文献   

18.
A portable inclineable articulated strut slip tester (PIAST) is a slipmeter that is widely used in the USA to measure coefficient of friction (COF) at the shoe sole and floor interface. A determination of a slip at the measurement interface, which is currently judged subjectively by operators, plays a crucial role in deciding the outcomes of a PIAST measurement. The goal of this study was to develop an objective determination of a slip based on the movement of the weight used by the slipmeter. The displacement of the weight and the time duration of consecutive strikes in a measurement were used to derive the objective slip criterion. Various footwear materials, floor materials and surface conditions were used to cover a wide range of COF values. The results of the regression analysis indicated that the objective COF predicted by the method developed in the current study was significant (R2 = 0.997, β = 0.991, p < 0.001) in predicting the subjective COF determined by the operator.  相似文献   

19.
A 2-m, adiabatic column has been successfully refurbished and recommissioned for coal self-heating research at The University of Queensland. Subbituminous coal from the Callide Coalfields reached thermal runaway in just under 19 days from a starting temperature of 20–22 °C. The coal was loaded as two layers, with an R70 index of 2.73 °C h−1 and 5.90 °C h−1 for the upper layer and lower layer respectively. Initially, a hotspot developed in the upper layer between 120 and 140 cm from the air inlet due to moisture adsorption. After 7 days, self-heating in the lower half of the column began to take over, consistent with the higher R70 index of this coal. The location of the final hotspot was approximately 60 cm from the air inlet. Further tests on Australian coals, with the column, will enable a better understanding of coal self-heating under conditions closely resembling mining, transport and storage of coal. The results from the column will also provide industry with the information needed to manage the coal self-heating hazard.  相似文献   

20.
We theorized that organization–environment adaptation, the interaction between external demands and personnel resources, predicts distress and morale. We tested this hypothesis in 29 stations within one state police department, and combined three data sources. We measured environmental demands for policing via census data pertaining to the station precinct (e.g., per cent unemployed; per cent in public housing). We assessed resources via personnel numbers within stations. Outcomes were employee's perceptions of staff distress and morale at the station (N = 247), assessed twice, 14 months apart. Using hierarchical linear modeling, we found that environmental demands predicted perceptions of workgroup distress and morale and that the relationships were moderated by personnel resources. For distress, when resources were low, demands were positively associated with distress; when resources were high, demands were negatively associated with distress. For morale, when resources were high, demands were positively associated with morale; there was no relationship when resources were low. Results show that aversive and pleasurable reactions at work may be traced to how resources are employed to manage external demands. Results support a macro‐level shift in modeling distress and morale, incorporating external demands, and strategic management decisions regarding personnel resourcing. Our research suggests that rather than being a result of individual failure to adapt, compromised work ability may result from an organizational failure to adapt to the environmental context. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

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