Vol 10 No 4 (2018)

Published: 2018-12-24

Original Article(s)

  • XML | PDF | downloads: 62 | views: 238 | pages: 179-190

    A decrease in body temperature can impair manual performance leading to a lowered capacity to carry out a certain activity. This study was aimed to analyze the extent effects of extreme cold air exposure on workers’ manual performance. The study population was consisted of 50 outdoor auto mechanics that were participated in two experiments carried out in winter and spring. Following a standard method, air environmental factors in each workstation and the physiological responses of the participants were measured. Touch sensory test was conducted to determine the sensory function of the hand. The grip strength and manual dexterity tests were also performed to assess manual work disability. The hand grip and pinch grip strength of the auto mechanics were reduced by 10.3% and 10.1% in cold air, respectively, as compared with the neutral air. Manual dexterity of the auto mechanics was also decreased from 6.3% to 8.8 % in cold air, as compared with neutral air. The prevalence of finger sensation disorders in the auto mechanics was 62% in cold air, while it was only 4% in neutral air. There was also a significant correlation between finger skin temperature and manual dexterity (r=-0.80, p<0.01), hand grip strength (r=0.74, p<0.01), and pinch grip strength (r=0.79, p<0.01). There was also a significant correlation between finger sensory function and manual dexterity (r=0.65, p<0.01). During extreme cold air exposure, the physiological and sensory changes have significantly reduced the manual performance of the auto mechanics. This study were able empirically provide a database for further researches on other aspects of the performance of workers exposed to cold air.

  • XML | PDF | downloads: 49 | views: 259 | pages: 191-198

    This study was aimed to investigate the moderator role of psychological capital relationships between occupational stress and work-life quality. In this cross-sectional study, the population were selected among all faculty members at the University of Bojnord. One-hundred and fifty faculty members were selected as samples. The study questionnaires were included occupational stress, psychological capital and work-life quality. The multiple regression analysis was examined research’s hypothesis using SPSS software version 22. According to findings, the correlation coefficients between occupational stress and work-life quality (r=-0.595, p<0.0001) and between psychological capital and work-life quality (r=0.421, p<0.0001) which all were statistically significant. The interaction of occupational stress and psychological capital, beyond effects of the main variables, created 2.8% of the increased variance for the model which indicates these variables have a meaningful interaction with each other in predicting of work-life quality  (ΔR2=0.028, ΔF= 6.15, p< 0.02). The results showed the importance of psychological capitals moderator relationships between occupational stress and work-life quality among the faculty members. Therefore, in order to reduce the effects of occupational stress on work-life quality, it is recommended that universities enhance psychological capital of faculty members through practical training protocols.

  • XML | PDF | downloads: 113 | views: 240 | pages: 199-208

    The purpose of this study was to determine the level of risk perception and assessment of the rate and factors of unsafe behavior among firefighters operating in Tehran.
    The effect of education, awareness, personality capability, coordination in team work, environmental factors, neurological stresses, and systems motivational on the firefighters’ risk perception and the rate of unsafe behavior in operational units were investigated. The data was collected using interview and an author’s made risk perception questionnaire. The validity and reliability of questionnaire were investigated in this study and then used for data collection. The sample randomized allocation method was used to analyze among 510 operational personnel including district directors and deputies, station heads, commanders, caretakers and firefighters.
    The results of this study showed that education, awareness, personality capability, coordination in teamwork and the motivational systems of firefighters operating units influence risk perception and the rate of unsafe behavior.
    The results demonstrated that risk perception was played an important role on the rate of unsafe behavior among firefighters. Moreover, the results showed that some important organizational and individual characteristics which should be considered for high risk process and operations uninfluenced by risk perception.

  • XML | PDF | downloads: 25 | views: 251 | pages: 209-217

    Undoubtedly, one of the main sources of noise pollution in cities is educational centers. The subject of discussion in related studies has always been the effects of noise pollution on educational centers, but almost none of them have ever looked at the subject from the perspective that these centers can also be an important source of noise pollution in urban areas. Therefore, this research, with a different approach, was addressed the effect of educational centers as an important source of noise pollution in urban areas. For this purpose, a total number of 32 state and nonprofit schools were selected randomly from north, south, east, and west of Tehran City. Then, after identifying different sources of noise in the schools, their sound level was measured by TES sound level meter (model, 1358), at distances of 10, 20, and 30 m from the centers. The measurement parameters included 10-minute equivalent sound pressure meter (Leq10min), maximum sound level (Lmax), and minimum sound level (Lmin). Daily average sound level (Ld) was another parameter calculated for a period of 15 hours (from 7 am to 22 pm). According to the results, at the nearest distance to the schools (10 m), the highest average Lmax was 69 dB (A), measured at the time of students’ departure. Its lowest was 64.7 dB (A) measured at the time the students had physical education class. The highest and average Ld levels at the distance of 10 m from the schools were 65.2 dB (A) and 59.2 dB (A), respectively, in state male primary schools and nonprofit female high schools. The average outdoor Leq and Ld level in the areas surrounding the target schools was about 5.5 dB (A) higher than the ambient noise. According to the results of the study, noises from schools may be considered as a disruptive factor in urban environments which has to be paid more attention.

  • XML | PDF | downloads: 82 | views: 234 | pages: 218-225

    A person’s beliefs may affect their job performance conceptions, work place and conditions. The present paper was aimed to appraise irrational beliefs and its impact on elementary school teacher’s organizational commitment. The current research was based on surveys. Shiraz elementary school male teachers were selected as a statistical population. Consequently, 211 participants were randomly selected using Kersji and Morgans’ sample size table. The measuring instrument was the 40-Items questionnaire of irrational beliefs-Ahvaz version, and Allen and Meyer’s 18- Items organizational commitment questionnaire. The results showed that helplessness for change (t=8.915, p<0.001), problem avoidance (t=11.945, p<0.001) and emotional irresponsibility (t=13.092, p<0.001) were significantly lower than mean, and approval demand (t=3.969, p<0.001) was significantly higher than mean. The results also showed that affective (t=1.602, p>0.111) and normative (t=0.833, p>0.406) commitments were at the mean level and continuous commitment (t=3.980, p<0.001) was higher than mean significantly. Moreover, the results showed that irrational beliefs affect the teacher’s organizational commitment. The correlation coefficient of irrational beliefs in organizational commitment was calculated 0.457, affective commitment 0.387, continuous commitment 0.473, and normative commitment 0.227, respectively. The study was concluded that irrational beliefs have a significant impact on teacher’s organizational commitment. It seems that irrational beliefs can be considered as individual factors influencing organizational commitment.


  • XML | PDF | downloads: 44 | views: 206 | pages: 226-235

    The present study was explored whether emotional intelligence and social cognitive variables were related to risky driving behavior (speed and lane deviation). Driving behavior was considered as a key predictive factor in road traffic accidents. In this study, the sample were comprised 75 adults between 20- 30 years old (M = 26.80, SD = 3.175) who currently held a valid driver’s license. Emotional Intelligence was assessed via self-report using the EQ-i - Bar-on Emotional Quotient Inventory (EQ-i), and driving behavior was measured using a driving simulator. Different driving behaviors were recorded including speed and lane deviation. The objective data obtained from the simulator were compared to scores result from the emotional Intelligence. Spearman correlations were revealed that age, driving experience and accident cases were related to driving behavior. There was a significant negative relationship among the average speed on roads with subscales of EI except in assertiveness (r=.448). The average speed was correlated positively with assertiveness. The lane deviation score showed significant negative relationship with subscales of EI except in assertiveness (r=.873). This study proposed that programs should be developed to change the attitude of drivers to engage in risky behavior and encourage safe and responsible. It may lead to safer behavior in traffic and a reduction in the number of accidents.

  • XML | PDF | downloads: 29 | views: 56 | pages: 236-249

    Risk of injury or death due to occupational incidents in the oil and gas industries is higher than that of major incidents such as fire or explosion. In 2017, the largest proportion (36%) of fatalities and greatest number of incidents (24%) in the oil and gas industries were categorized as Struck-by. This study was aimed to develop a Bayesian network (BN) model for predicting occupational struck-by incident probability. Nineteen struck-by causal factors were extracted from the literature. Expert knowledge in addition to Dempster-Shafer theory was used to construct a BN. A questionnaire was developed to measure conditional probabilities of causal factors among participants. Struck-by probabilities of different states of causal factors were also estimated. The prior probability of struck-by incident was 3.09% (approximately 31 per 1000 operational workers per year). Belief updating predicted that preventing workers from being in improper position (in line of fire) would decrease the struck-by incidents by 37%. In contrary, failure of hazard warning (true state) and violation of procedures increased the struck-by probability by 4.08% (an increase of 32%) and 3.96% (an increase of 28%), respectively. The proposed BN model predicted that preventing workers from being in improper position (in line of fire) would decrease the struck-by occupational incidents by 37%. This approach was a step toward quantification of risks associated with occupational incidents. It had advantages including graphical representation of causal factors relationships, easily customizing model, and simply introducing of new evidence (belief updating).

Review Article(s)

  • XML | PDF | downloads: 75 | views: 295 | pages: 250-264

    Early detection of noise-induced hearing loss is important to prevent the extension of hearing loss to speech frequencies. This study was assessed the efficacy of high frequency audiometry for early detection of NIHL by a systematic review of literature and meta-analysis. A systematic literature search was performed in Medline, Scopus, ISI web of science, EMBASE, CINAHL, Health star, and Ovid databases. Mean difference between hearing threshold in conventional and high frequencies was considered as the effect size. Pooled and stratum-specific MD was estimated. The number of 23 and 11 systematic review and meta-analysis studies were entered respectively throughout 3031 articles which initially searched. Since mean difference was higher in exposed subjects than non-exposed ones in most hearing frequencies, therefore, the effect size was higher in high frequencies, though not statistically significant. High frequency audiometry cannot be considered as a method for early detection of NIHL.