The effect of age on cognitive performance under the impact of vibration in a driving environment.

The effect of organismic variable age on human cognitive performance was studied under the impact of vibration in different automobile driving environments, namely city streets, rural roads and highways. Reaction time was measured in milliseconds through a human response measurement system specifically designed for the purpose. Results of the study showed that age had a significant effect in city street and rural road conditions. It was also found that the level of equivalent acceleration of vibration and a difficulty index significantly affected cognitive performance in all driving conditions. The organismic variable age observed to have a significant effect on task performance implied that youngsters and older people are stressed differently in specific environments of driving so proper stress management strategies should be evolved for them in order to minimize the number of accidents.     

A study on the combined effect of noise and vibration on operators' performance of a readability task in a mobile driving environment.

This paper presents a study in which the main objective was to investigate the combined effect of noise and vibration on the performance of a readability task in a mobile driving environment. Subjects performed a readability task on a laptop computer in a sitting posture with their backs supported with a backrest under varying levels of noise and vibration. The data in terms of the mean number of characters read per minute were collected and statistically analyzed. Results showed that the individual effect of noise, vibration, and the operators' gender as well as the interaction between gender and noise, and gender and vibration were statistically significant. However, the combined effect of noise and vibration was not found to be statistically significant. Results also indicated that gender was statistically significant at all levels of noise as well as vibration, and noise and vibration were statistically significant at both levels of gender.     

The impact of choice of rewards and feedback on task performance

A laboratory experiment (N = 149) tested two hypotheses: that choice of reward will have a positive impact on task performance and that choice would lead to arousal, as measured by reaction speed. The role that feedback information concerning whether subjects were being rewarded for performance on a prior task was also examined. The results revealed that choice and choice interacting with feedback were related to performance, but the choice had no impact on arousal. Self-determination theory may be used to help interpret these findings. The choice and feedback are non-controlling and informational to recipients which may increase perceptions of competence and self-initiative with an accompanying increase in intrinsic motivation to perform well on the task. These theoretical implications and some questions for future research and practical applications are discussed.     

Upper trapezius fatigue in carpet weaving: the impact of a repetitive task cycle

Introduction. Shoulder disorders are one of the most prevalent musculoskeletal disorders among carpet weavers. The most important cause of these disorders is muscle fatigue. The aim of the present study is to investigate the effect of carpet weaving characteristics on upper trapezius (UTr) muscle fatigue during a task cycle. Method. In this cross-sectional study, 9 women and 3 men participated. During an 80-min cycle of carpet weaving, a times-series model was applied to assess electromyography amplitude and frequency changes. Result. According to the joint analysis of electromyogram spectrum and amplitude method, the participants experienced 0% force decrease, 0.9% recovery, 18% force increase and 72% fatigue in the left UTr. Furthermore, the rates of force decrease, recovery, force increase and fatigue in the right UTr were 18%, 18%, 18% and 45%, respectively. Fatigue in the right and the left UTr was reported to be the dominant state during one carpet weaving task cycle. Conclusion. Task cycle appears to have a significant impact on UTr fatigue in participants, and UTr fatigue can be considered a serious risk factor in shoulder musculoskeletal disorders. Hence, further studies should focus on better workstations and work–rest periods during various subtasks.     

The effect of an ergonomic intervention on musculoskeletal, psychosocial and visual strain of VDT data entry work: the Norwegian part of the international study.

The Norwegian MEPS (musculoskeletal--visual--psychosocial--stress) study included 3 groups: data entry, data dialogue (female) and data dialogue (male). Before intervention, the data entry group reported significantly more symptoms and signs of musculoskeletal illness and had longer periods in front of the video display terminal (VDT) without a break. The ergonomic intervention consisted mainly of ergonomic information and training. After intervention, the data dialogue female group reported a significant reduction in shoulder pain in parallel with a reduction in trapezius load. Increasing the understanding in how to adjust the work stand and chair may have been contributing factors to reducing the pain level. There was a significant reduction in eye problems in all groups; the greatest reduction in eye symptoms was seen in the groups who had new optometric corrections.     

The effect of an ergonomic intervention on musculoskeletal, psychosocial, and visual strain of VDT data entry work: the Polish part of the international study.

A group of routine data entry operators (female) was included in the Polish MEPS (musculoskeletal--eyestrain--psychosocial--stress) study. Before the intervention, ergonomic assessment revealed improper working conditions such as inadequate lighting, uncomfortable chairs, and lack of forearm and wrist support while medical examination revealed that trapezius muscle load along with upper arm, head and back angles were higher than advisable. Subjects complained about neck and shoulder pain, visual problems, and psychosocial conditions. The ergonomic intervention included installation of new luminaires and Venetian blinds, new chairs, repair of ventilators, and optometric corrections. The results after the intervention showed mainly improvement in chair comfort, lighting conditions, visual strain, and sitting posture. However, financial limitations did not allow satisfactory completion of the intervention leading to a mixed interpretation of the results.     

爆破振动效应影响评价及减震措施研究

爆破地震效应是工程爆破产生的主要危害之一,如何保证工程爆破时爆区周围建筑物、基础设施等的安全运行,对爆破的地震效应进行实测和振动效应影响评价是十分必要的.以水电站左岸边坡工程爆破对右岸化工厂的影响为例,根据实测爆破振动速度和爆破振动频率,通过对测试结果线性回归分析,得到不同区域爆破地震波的传播和衰变规律.根据实测结果和数值计算,评价了左岸工程爆破对江右岸化工厂及区内建筑物的振动影响,论述了控制爆破振动强度、减小振动效应的措施.     

The effect of an ergonomic intervention on musculoskeletal, psychosocial, and visual strain of VDT data entry work: the United States part of the international study.

The United States MEPS (musculoskeletal--eyestrain--psychosocial--stress) study consisted of 1 group of 28 female data entry operators. The intervention was in 3 parts: workstation redesign (including advanced ergonomic chairs, motorized adjustable workstations, advanced adjustable keyboards, adjustable copyholders, adjustable footrests, monitor support surfaces) and ergonomic training/coaching and corrective lenses. After the intervention, statistically significant reductions in physical signs (trigger points, neck and shoulder mobility), subjective reports of intensity and frequency of musculoskeletal pain, and subjective reports of visual problems were observed. Static load during the work sample, as assessed by experts, improved after the intervention as did measured postural angles of head and trunk and subjective assessment of users of ergonomic characteristics of the workplaces. For all of these measures, improvements observed 1 month after intervention were also observed in the 1-year follow-up. Trapezius load, as assessed by electromyography (EMG), decreased after intervention, but then increased in the follow-up. The increase was interpreted as a calibration problem.     

地表夯击载荷作用下埋地管道力学分析

为研究地基强夯作业中夯击载荷对埋地管道力学性能的影响,基于有限元原理建立了夯锤-管道-围土耦合三维模型,分析了夯击过程中管道截面变形及所受冲击力变化规律,研究了管道壁厚、夯击速度、夯锤体积对管道应力、应变及变形的影响规律。结果表明:夯击载荷下的管道所受冲击力为脉冲型,且随时间推移逐渐降低为0,最大冲击力随管道壁厚、夯击速度、夯锤体积增大而增大;管道最大等效应力、高应力范围及最大等效塑性应变随壁厚增加而减小,但随夯击速度或夯锤体积增大而增大;随着夯击速度、夯锤体积增大,管道截面变形率（椭圆度或凹陷率）逐渐增大,但其随壁厚增加而减小。     

The effects of proximal and distal goals on performance on a moderately complex task

The effect of a proximal plus a distal goal was investigated relative to setting only a distal goal or urging participants to do their best. Young adults (N=39) were paid on a piece rate basis to make toys. An analysis of variance revealed that the amount of money earned by the participants who were urged to ‘do your best’ was significantly greater than the amount of money earned by the participants who were assigned a distal goal. However, the amount of money earned by the participants who were assigned proximal goals, in addition to a distal goal, was significantly greater than the amount of money earned by the participants in the ‘do your best’ condition. The correlation between perceived self‐efficacy and the amount of money earned was 0.45 (p<0.01). Perceived self‐efficacy significantly increased only for those participants in the proximal plus distal goal condition. Proximal goals, through self‐efficacy and performance feedback, appear to have focused attention on task appropriate strategies. The results suggest an informational explanation of proximal goals as opposed to a motivational one through goal commitment. Implications of these findings for mentoring and training are discussed. Copyright © 1999 John Wiley & Sons, Ltd.     

Incentives and cooperation: the joint effects of task and reward interdependence on group performance

We examine the joint effects of task interdependence and reward interdependence on group behavior and performance. We develop a model that predicts that task and reward interdependence will interact to increase performance, and present results of a laboratory experiment that confirms our prediction. We explore the efficacy of group reward systems for different task designs, and the relationship between cooperation and performance. We confirm earlier results on the weakness of the free-rider effect in small face-to-face groups. We also find, surprisingly, that while reward interdependence is important to performance, task interdependence, but not reward interdependence, drives observed cooperative behavior. This last result suggests caution in interpreting the efficacy of changes in the design of work. Such changes, if unaccompanied by changes in the design of the reward system, are likely to appear successful in terms of observed cooperation, but may not enhance performance. © 1997 by John Wiley & Sons, Ltd.     

Technical‐administrative task performance,leadership task performance,and contextual performance: considering the influence of team‐ and task‐related composition variables

The purpose of the present study was to examine how the mix of ability, experience, and personality impacts three types of team performance: technical‐administrative task performance, leadership task performance, and contextual performance. Relationships were tested using data collected from student management teams, who were required to plan and supervise the preparation and service of meals in a cafeteria‐style dining room patronized by university students, staff, and faculty. Results revealed that both team‐ and task‐related composition variables predicted leadership and contextual performance. Specifically, grade point average was significantly related to technical‐administrative task performance, and extraversion, neuroticism, and grade point average were related to leadership task performance. Agreeableness and restaurant experience predicted contextual performance. Surprisingly, conscientiousness did not account for significant variance in any of the three types of performance measured. The implications of these findings for the study of team performance in organizations are discussed. Copyright © 2002 John Wiley & Sons, Ltd.     

Investigating the nonlinear effect of ego depletion on safety compliance: The moderating role of rumination

IntroductionA general view in previous research is that employees are reluctant to follow safe work procedures when confronting the shortage of self-control resources. However, this argument is constrained by the restricted view of ego depletion. To fill this gap, this study constructs the nonlinear relationship between ego depletion and safety compliance drawing from the perspective of dual-process theory.MethodRegression analysis and hierarchical linear model are used to test our hypothesis.ResultsBy investigating 241 medical staffs, we find that the relationship between ego depletion and safety compliance is U-shaped. This U-shaped relationship is replicated through 221 daily data for 50 medical staffs. In addition, the U-shaped relationship between ego depletion and safety compliance can be enhanced by rumination.DiscussionsFindings of our study contribute to providing a nuanced explanation about the effect of ego depletion on safety compliance. Also, this study has important implications for High Reliability Organizations to motivate depleted employees to engage in safety compliance behaviors.     

Representativity and univocity of traffic signs and their effect on trajectory movement in a driving-simulation task: Regulatory signs

Introduction: The effect of traffic signs in the motor behavior of drivers is not completely understood. Knowing how humans process the meaning of signs (not just by learning, but instinctively) will improve reaction time and decision making when traveling. The economic, social, and psychological consequences of car accidents are well studied. Every effort to find the solution of this social problem is encouraged. Method: This study identifies which traffic signs are more ergonomic for participants, from a cognitive point of view, and determines, at the same time, their effect in participants' movement trajectory in a driving-simulation task: the tracking task. Results: The results point out that the signs least representative of their meaning produce a quantitative and qualitative different deviation from the center of the road than the most representative ones.     

Experimental evidence for the effects of task repetitiveness on mental strain and objective work performance

People frequently have to work in high repetitive jobs. Previous research has focused exclusively on the effects of task repetitiveness on well‐being, while neglecting effects on work performance. In the present study, we aimed to fill this void by conducting two workplace simulations with experimental manipulations of task repetitiveness. Participants worked for about 5 hours at either a computer workstation, compiling computer hardware packages according to customer requests (Experiment 1, N = 160), or at an assembly line, piecing together equipment sets for furniture (Experiment 2, N = 213). Both experiments provide consistent evidence that high repetitiveness has a detrimental effect on well‐being, whereas work performance increases under conditions of high repetitiveness. On a practical level, our study hence shows that high task repetitiveness is a double‐edged sword for both employees and organizations. On a conceptual level, our findings emphasize the necessity to account for both mental strain and work performance when examining the effects of task repetitiveness. Copyright © 2014 John Wiley & Sons, Ltd.     

装修改造对结构整体安全性影响分析

归纳了危害结构安全的主要装修改造行为,提出装修改造对结构安全性影响应以整体结构为研究对象,分析结构整体抗力的变化。以实际工程为例,对装修改造前后建筑结构进行设计复核,重点分析了建筑荷载增加、承重墙窗下墙拆除对结构安全性的影响。指出在各种装修因素综合作用下,结构承重体系发生改变,尤其是抗震薄弱构件的出现,使结构整体抗震能力大大降低。提出保证建筑结构安全性的合理化建议,对防止突发性灾害具有重要意义。     

The power of reflection for would-be leaders: Investigating individual work reflection and its impact on leadership in teams

This paper examines the key role that individual work reflection plays in facilitating individuals' leadership in teams. Consistent with the functional perspective on leadership, we argue that individual work reflection allows individuals to better understand their team's needs, and therefore enact higher levels of task-, relational-, and change-oriented leadership behaviors and be more effective leaders in their teams. We first conducted a series of measure development studies to validate a measure of individual work reflection comprising four dimensions of reflection at work: goals-, methods-, relationships-, and self-focused reflection. Then, across two independent studies assessing individuals in self-managing teams over time, we found support for our theoretical model linking individual work reflection to peer-rated leadership behaviors (Main Studies 1 and 2) and leadership effectiveness (Main Study 2). In further support of our theorizing, Main Study 2 also indicates that individual work reflection shapes leadership behaviors and effectiveness via understanding the team's needs, beyond a wide range of related constructs (e.g., feedback seeking, mindfulness, and rumination), as well as commonly studied predictors of leadership behaviors (i.e., the Big Five). Our theory and empirical findings help advance insights on the role of individual work reflection in improving leadership outcomes in organizations.     

British directors perspectives on the impact of health and safety on corporate performance

Occupational health and safety is established as a factor in international competitiveness, but we question the relevance of this economic argument at the organisational level. On this basis we assess the place of health and safety in the senior management agenda, based on findings from recent market research. Out of this we take a brief perspective on the literature on performance assessment and corporate reputation, and their relationship with health and safety in the workplace. We then report original in-depth research on directors' attitudes to and practice in workplace health and safety. We conclude with a summary of the key issues and a discussion of directions for further work.     

Whole-body vibration in heavy equipment operators of a front-end loader: Role of task exposure and tire configuration with and without traction chains

IntroductionThis study measured whole-body vibration (WBV) exposures in front-end loader operators, and evaluated the effects of traction chains and work tasks on their WBV exposures.MethodWBV exposures were measured and compared across three different front-end loader tire configurations: (a) stock rubber tires, (b) rubber tires with ladder chains, and (c) rubber tires with basket chains. The operators completed three distinct standardized tasks: driving on a city street, simulated plowing, and a simulated scooping and dumping task. A portable data acquisition system collected tri-axial time weighted and raw WBV data per ISO 2631-1 and 2631-5 standards. In addition, Global Positioning System (GPS) data were collected in order to compare loader speeds across tire conditions and the standardized tasks.ResultsRelative to the stock rubber tires, both types of tire chains significantly increased WBV exposures with the ladder chains having substantially higher WBV exposures compared to basket chains. Additionally, there were task dependent differences in WBV exposures. During the driving task, the z-axis (up and down) was the predominant exposure; the plowing task had a more even distribution of exposure across all three axes; while during scooping and dumping task, the x-axis (fore and aft) had the highest WBV exposures. The GPS data indicated that there were significant speed differences across tasks but not between the basket and ladder chain conditions.ConclusionsTires with ladder chains increased the front-end loader operators' exposure to WBV above the ISO 2631-1 recommended eight hour action limit increasing risk for adverse health effects. Although more expensive, basket chains are recommended over ladder chains since they substantially lowered the front-end loader operator's exposures and may ultimately reduce vibration related wear and tear on the vehicle.Impact on IndustryIn order to reduce a heavy equipment vehicle (HEV) operator’s chances for developing low back pain, this study provides information that health and safety professionals can use to reduce whole-body vibration (WBV) exposures when operating front-end wheel loaders with traction chains.