A comparative investigation of machine learning algorithms for predicting safety signs comprehension based on socio-demographic factors and cognitive sign features.

This study examines whether the socio-demographic factors and cognitive sign features can be used for envisaging safety signs comprehensibility using predictive machine learning (ML) techniques. This study will determine the role of different machine learning components such as feature selection and classification to determine suitable factors for safety construction signs comprehensibility. A total of 2310 participants were requested to guess the meaning of 20 construction safety signs (four items for each of the mandatory, prohibition, emergency, warning, and firefighting signs) using the open-ended method. Moreover, the participants were asked to rate the cognitive design features of each sign in terms of familiarity, concreteness, simplicity, meaningfulness, and semantic closeness on a 0-100 rating scale. Subsequently, all eight features (age, experience, education level, familiarity, concreteness, meaningfulness, semantic closeness, and simplicity) were used for classification. Furthermore, the 14 most popular supervised classifiers were implemented and evaluated for safety sign comprehensibility prediction using these eight features. Also, filter and wrapper methods were used as feature selection techniques. Results of feature selection techniques indicate that among the eight features considered in this study, familiarity, simplicity, and meaningfulness are found to be the most relevant and effective components in predicting the comprehensibility of selected safety signs. Further, when these three features are used for classification, the K-NN classifier achieves the highest classification accuracy of 94.369% followed by medium Gaussian SVM which achieves a classification accuracy of 76.075% under hold-out data division protocol. The machine learning (ML) technique was adopted as a promising approach to addressing the issue of comprehensibility, especially in terms of determining factors affecting the safety signs' comprehension. The cognitive sign features of familiarity, simplicity, and meaningfulness can provide useful information in terms of designing user-friendly safety signs.

Effects of traffic sign design and personal characteristics on the usability of traffic signs.

BACKGROUND: Previous researchers examined the effects of either drivers' personal characteristics or traffic sign design features on the usability of traffic signs. Their research indicated a connection existed between personal characteristics and usability and between design features and usability. OBJECTIVES: The focus of this study was to investigate which personal characteristics of drivers and which features of traffic sign design affect traffic sign usability the most. METHODS: The study was conducted in three stages. In the first stage, the participants filled out a questionnaire designed to record each driver's personal characteristics. In the second stage, a System Usability Scale (SUS) was used to evaluate the subjective usability of traffic signs. The SUS had 10 statements that participants (N = 386) scored on a 5-point Likert-type scale from strongly agree to strongly disagree. In the third stage, these participants assigned from 0 to 100 points to 20 signs based on participant perception of the five design features of familiarity, concreteness, simplicity, meaningfulness, and semantic distance. RESULTS: The results showed that four of the five personal characteristics studied (age, education level, possession of a driving license, and formal driving experience) correlated significantly with traffic sign usability. The exception was gender, which did not correlate significantly. Additionally, it was found that the five traffic sign design features correlated in varying degrees of significance with each other and with specific traffic signs. CONCLUSIONS: Traffic sign usability depends mostly both on driver education level and age group and on the design feature of meaningfulness. These findings have implications for how drivers should be trained and how signs should be designed.

Hand functionality in dentists: the effect of anthropometric dimensions and specialty.

Objectives. This study aimed to investigate the relationship between dentists' hand functionality (handgrip, tip-to-tip pinch, key pinch and palmar pinch strengths) and dental specialty (maxillofacial surgery, endodontics, pediatric dentistry), socio-demographic factors and hand-forearm anthropometric dimensions. Methods. A cross-sectional study was designed in which 720 certified dentists (330 males and 390 females) voluntarily participated in the study. A tape measure (±0.1 cm) and a digital caliper (±0.1 mm) were used to measure anthropometric dimensions. A Jamar dynamometer and pinch gauge were used to measure hand strength variables. Results. Hand strengths decreased with age and clinical experience, and were always greater in male than female dentists. Maxillofacial surgeons aged 35-39 years attained the highest values of handgrip and key pinch strengths, while endodontists aged 30-34 years attained the peak values of tip-to-tip pinch strength. Among the measured hand dimensions, forearm circumference was significantly greater in maxillofacial surgeons compared with endodontists and pediatric dentists. Conclusion. Hand functionality is specialty-related among dentists because distinct dental specialties expose practitioners to different task demands. Like any other manual workers, dentists need more ergonomic and usable hand tools tailored not only to the intended application but also to the anthropometry of users.

Normative data for handgrip strength in Iranian healthy children and adolescents aged 7-18 years: comparison with international norms.

BACKGROUND: Grip strength is an essential component of physical fitness. The objective of this study was to develop normative handgrip strength data for Iranian healthy boys and girls comparing their handgrip strength with international reference values. METHODS: Handgrip strength was measured in 2637 healthy children/adolescents (1391 boys and 1246 girls), aged 7-18 years, using a standard adjustable Jamar hand dynamometer (Model 5030 J1, Sammons Preston Rolyan, Bolingbrook, IL, USA). Body mass (kg) and stature (cm) were measured and body mass index was computed in kg/m2. The sample was stratified by gender, age, and hand preference. RESULTS: Handgrip strength increased with age and was considerably higher in boys than in girls for all age groups (p < 0.001). Grip strength had a parallel and linear growth for both genders until the age of about 11 years and showed a steeper upward slope in boys than in girls thereafter. The findings of the current investigation were significantly different from those of the previously published normative data, especially for boys over the age of 12 years and girls in the age range of 7-18 years (p < 0.001). This difference was mainly in such a way that the Iranians had lower handgrip strength. CONCLUSIONS: The differences between present results and those of similar available in the literature in this field emphasize the significant role of using normative data specific to a particular population in research or clinical settings.

Analysis of hand-forearm anthropometric components in assessing handgrip and pinch strengths of school-aged children and adolescents: a partial least squares (PLS) approach.

BACKGROUND: The purpose of this study was to examine the influence of hand-forearm anthropometric dimensions on handgrip and pinch strengths among 7-18 years children and adolescents and to investigate the extent to which these variables can be used to predict hand strength. METHODS: Four types of hand strengths including handgrip, tip to tip, key, and three-jaw chuck pinches were measured in 2637 healthy children and adolescents (1391 boys and 1246 girls) aged 7-18 years using standard adjustable Jamar hydraulic hand dynamometer and pinch gauge. A set of 17 hand-forearm anthropometric dimensions were also measured with an accurate digital caliper and tape measure. RESULTS: No significant differences were found between the hand strengths of boys and girls up to the age of 10 years. Gender related differences in handgrip and pinches were observed from the age of 11 years onwards, with boys always being stronger. The dominant hand was stronger than the non-dominant hand (8% for handgrip and by about 10% for all three types of pinches). The strongest correlations were found between the hand length and hand strengths (r > 0.83 for handgrip and three all pinches; p < 0.001, 2-tailed). Based on the partial least squares (PLS) analysis, 8 out of 17 anthropometric indices including hand length, hand circumference, thumb length, index finger length, middle finger length, and forearm length had considerable loadings in the PLS analysis, which together accounted for 46% of the total variance. CONCLUSIONS: These results may be used by health professionals in clinical settings as well as by designers to create ergonomic hand tools.

Guessability of U.S. pharmaceutical pictograms in Iranian prospective users.

OBJECTIVE: This study examined the gueassability of US pharmaceutical pictograms as well as associated demographic factors and cognitive design features among Iranian adults. METHODS: A total of 400 participants requested to guess the meaning of 53 US pharmaceutical pictograms using the open-ended method. Moreover, the participants were asked to rate the cognitive design features of each pictorial in terms of familiarity, concreteness, simplicity, meaningfulness and semantic closeness on a scale of 0-100. RESULTS: The average guessability score (standard deviation) was 66.30 (SD=24.59). Fifty-five percent of pharmaceutical pictograms understudy met the correctness criteria of 67% specified by ISO3864, while only 30% reached the criterion level of 85% set by ANSIz535.3. Low literate participants with only primary school education had substantial difficulty in the interpretation of pharmaceutical pictograms compared to those completed higher education levels. Younger adults of <30 years significantly performed better in the interpretation of pharmaceutical pictograms as compared to >31 years old participants. 'Home patient care' and 'daily medication use' had no effect on guessability performance. Concerning cognitive design features, meaningfulness better predict geussability score compared to the others. CONCLUSIONS: Several USP pictograms fail to be correctly interpreted by Iranian users and need to be redesigned respecting cognitive design features. Interface designers are recommended to incorporate more familiar and concrete elements into their graphics in order to create more meaningful pictorial symbols and to avoid any misinterpretation by the user. Much effective medication use is expected to be achieved by means of this approach, through the improvement of the communication property of pharmaceutical pictograms.

Maximum handgrip strength as a function of type of work and hand-forearm dimensions.

BACKGROUND: Handgrip strength is a measurement of upper extremity functionality and an indicator of overall physical ability. OBJECTIVES: The objective of this study was to compare maximum handgrip strength (MGS) between manual workers and office employees and to investigate if the expected difference is related to the anthropometric dimensions of the workers' hands and forearms. METHODS: This was a cross-sectional study with a sample of 1740 male workers (905 light manual workers; and 835 office employees), aged 20-64 years. Maximum voluntary contractions were obtained using a JAMAR dynamometer according to the methodology proposed by the American Society of Hand Therapy (ASHT). The highest value obtained from three trials was considered as the MGS for each side. Six anthropometric dimensions (i.e., hand length, palm length, forearm length, hand breadth, wrist circumference and forearm circumference) were measured by digital caliper and tape measure. RESULTS: Maximum handgrip strength of light manual workers (52.7±8.5 kg) was significantly higher than that of office employees (47.3±8.4 kg) (p < 0.001). Maximum handgrip strength was positively correlated with Hand breadth (r = 0.781 for light manual workers and r = 0.766 for office employees; p < 0.001) and Forearm circumference (r = 0.741 for light manual workers and r = 0.752 for office employees; p < 0.001); the only dimensions which were significantly different between the two studied job groups. CONCLUSIONS: The results of this study revealed that light manual workers are approximately 12.4% stronger than office employees in terms of maximum handgrip force. It is therefore imperative to consider the observed differences in clinical, workstations, and hand tool designs in order to increase efficiency and comfort at work.

Guessability of U. S. pharmaceutical pictograms in Iranian prospective users

OBJECTIVE: This study examined the gueassability of US pharmaceutical pictograms as well as associated demographic factors and cognitive design features among Iranian adults. METHODS: A total of 400 participants requested to guess the meaning of 53 US pharmaceutical pictograms using the open-ended method. Moreover, the participants were asked to rate the cognitive design features of each pictorial in terms of familiarity, concreteness, simplicity, meaningfulness and semantic closeness on a scale of 0-100. RESULTS: The average guessability score (standard deviation) was 66.30 (SD=24.59). Fifty-five percent of pharmaceutical pictograms understudy met the correctness criteria of 67% specified by ISO3864, while only 30% reached the criterion level of 85% set by ANSIz535.3. Low literate participants with only primary school education had substantial difficulty in the interpretation of pharmaceutical pictograms compared to those completed higher education levels. Younger adults of <30 years significantly performed better in the interpretation of pharmaceutical pictograms as compared to >31 years old participants. 'Home patient care' and 'daily medication use' had no effect on guessability performance. Concerning cognitive design features, meaningfulness better predict geussability score compared to the others. CONCLUSIONS: Several USP pictograms fail to be correctly interpreted by Iranian users and need to be redesigned respecting cognitive design features. Interface designers are recommended to incorporate more familiar and concrete elements into their graphics in order to create more meaningful pictorial symbols and to avoid any misinterpretation by the user. Much effective medication use is expected to be achieved by means of this approach, through the improvement of the communication property of pharmaceutical pictograms

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Development and validation of a new scale for prediction of low back pain occurrence among nurses.

There are several scales for prediction of low back pain (LBP) occurrence, but most of them only consider occupational aspect. This study aimed to develop and validate a new biopsychosocial scale for the LBP prediction among nurses. In this mixed-method study, a scale was developed by integrating the findings from the literature review and the semi-structured interviews. The qualitative and quantitative face and content validation were then performed. The construct validation was performed based on the hypothesis testing by independent-samples t-test using the SPSS in a case study with 241 nurses. The reliability of the scale was also tested through 15-day interval test-retest reliability by Intra Class Correlation Coefficient (ICC). Then the Minimum Detectable Changes (MDC) and MDC % was calculated. The results showed that the three dimensions (occupational, psychosocial and individual), consisted of 40 items, predict LBP occurrence. Both the scale and the three sub-scales could differentiate known groups of nurses in terms of LBP. These groups were nurses: with/without LBP during the past 12 years, with a high/low occurrence of LBP, with/without co-morbidity, being female/male, with/without night shift, and with high/low repetition of loads/patients handling. The average measure ICC of the scale was 0.866 (P <0.001). The MDC95 (MDC %) was 14.86 (15.65 %). We concluded that the proposed scale is a simple and trustworthy tool which supports the multidimensional nature of LBP.

Normative hand grip strength and prediction models for Iranian office employees.

BACKGROUND: Normative data on Hand grip strength has a wide range of application and is of great value. OBJECTIVE: To establish gender and age-specific reference data concerning hand grip strength of Iranian office workers, to explore possible relationships with demographic and anthropometric factors and to develop appropriate predictive models. METHODS: The study population included 418 (220 males and 198 females) Iranian office employees. They were divided into 5-year age-groups. Hand length, palm width, palm length, forearm length, wrist circumference, and forearm circumference were measured by means of a digital Caliper (±0.01 mm) and a tape meter (±0.1 cm). The value of hand grip strength was measured by JAMAR hydraulic dynamometer respecting the American Society of Hand Therapy recommendations. RESULTS: The average of grip strength for dominant and non-dominant hands (in Kg) respectively was 51.10±9.50 and 46.90±9.89 for male and 28.76±4.47 and 25.89±4.60 for female. Age was curvilinearly related to hand grip strength. All selected hand dimensions were highly correlated with grip strength; palm width, palm length and hand length being the most correlated ones, respectively. Prediction equations of hand grip strength were developed for dominant and non-dominant hands of both genders. CONCLUSIONS: Suggested norms would provide more accuracy for ergonomic designers as well as health practitioners especially with regards to proposed prediction models with which grip strength could be estimated faster and easier.

Anthropometric Estimations for Iranian General Population.

BACKGROUND: An essential requirement exists for a single exhaustive source of anthropometric databank in Iran. Available information about Iranian bodily dimensions is not applicable to the general population due to the sample of people investigated. This study aimed to present the first Iranian anthropometric databank by estimation. METHODS: After a systematic review, 24 relevant sources of information were found and included. No time limit was considered. The method of Rapid Anthropometrics Scaled for Height was used. RESULTS: Overall, 36 bodily dimensions were estimated, for which the seven percentiles of 1st, 5th, 25th, 50th, 75th, 95th, and 99th were calculated, stratified by sex. CONCLUSION: The resulting tables can be claimed as the most representative anthropometric databank for Iranian general 20-64 yr population now. Data are suitable for practical purpose and are applicable in both occupational and community setting.

A prospective study of psychomotor performance of driving among two kinds of shift work in Iran.

BACKGROUND AND AIM: Driving after a night shift imposes a risk on health care professionals and other road users. The aim of this study was to measure psychomotor performance of driving of night shift nurses compared to day-shift nurses. METHODS: Forty-seven volunteer female nurses working at Sina hospital in Tehran, Iran, with a call in all departments of hospital, participated in this study (23 night shift and 24 day shift nurses) in 2016. The tests included RT for simple reaction time, ATAVT for perceptual speed, LVT for visual orientation and ZBA for time anticipation. Data collection tools were individual characteristics, 11-item circadian type inventory (CTI), Stanford sleepiness scale (SSS), and Swedish occupational fatigue inventory (SOFI-20) questionnaires. Psychomotor driving performance was assessed using validated computerized traffic psychological battery of Vienna Test System (VTS), before and after the shifts. Data analysis was performed using paired-samples t-test and Linear Regression. RESULTS: The mean age of day and night-shift nurses were 31.4±5.6 and 28.7±3.9 years respectively, no significant difference between two groups. Thirty percent of night shift and 16.7% of day shift nurses reported traffic accidents in the past year. The results revealed that, scores based on viewing times in visual orientation test (p=0.005), and median reaction time score in choice reaction time and reactive stress tolerance test (p=0.045), had a significant association with a 12-hour night shift with a 3-hour nap. CONCLUSIONS: Twelve-hour night shift work impairs choice reaction time and visual orientation in nurses, even though they take a 3- hour nap during the shift. These skills are required for safe driving.

Demographic and occupational determinants of the work ability of firemen.

OBJECTIVES: Firefighters tackle various stressors that affect their health and job performance; therefore, assessment of their work ability is necessary. This study aimed to investigate the demographic and occupational determinants of the work ability of firemen. METHODS: In this cross-sectional study, 375 firemen working in Tehran Fire Department were randomly selected. Demographic, occupational, and work ability index (WAI) questionnaires were applied as research tools. RESULTS: The mean firemen's WAI score was relatively high. There were significant relationships between WAI and age, body mass index, work experience, and weekly leisure-time physical exercise hours. Single employees, those who did not have extra jobs and did not smoke, had greater scores compared to their counterparts. Poisson regression revealed that age and weekly leisure-time physical exercise hours could affect WAI significantly. CONCLUSIONS: Although Iranian firemen revealed good work ability, recognizing factors affecting this ability and preparing facilities to promote their function is necessary.

Influence of traffic-related noise and air pollution on self-reported fatigue.

A growing body of evidence suggests that exposure to environmental pollutions is related to health problems. It is, however, questionable whether this condition affects working performance in occupational settings. The aim of this study is to determine the predictive value of age as well as traffic related air and noise pollutions for fatigue. 246 traffic officers participated in this study. Air pollution data were obtained from the local Air Quality Control Company. A sound level meter was used for measuring ambient noise. Fatigue was evaluated by the MFI-20 questionnaire. The general and physical scales showed the highest, while the reduced activity scale showed the lowest level of fatigue. Age had an independent direct effect on reduced activity and physical fatigue. The average of daytime equivalent noise level was between 71.63 and 88.51 dB(A). In the case of high noise exposure, older officers feel more fatigue than younger ones. Exposure to PM10 and O3 resulted in general and physical fatigue. Complex Interactions between SO2, CO and NO2 were found. Exposure to noise and some components of air pollution, especially O3 and PM10, increases fatigue. The authorities should adopt and rigorously implement environmental protection policies in order to protect people.

Evaluation of Iranian microbiology laboratories for identification of etiologic agents of bacterial meningitidis. Survey results of an external quality assessment scheme (EQAS) programme.

OBJECTIVE: To determine the ability of Iranian microbiology laboratories for identification and susceptibility testing of Streptococcus pneumoniae and Haemophilus influenzae as causative agents of bacterial meningitides. METHODS: Two strains of bacteria including Haemophilus influenzae and Streptococcus pneumoniae as a common causative agents of meningitides were chosen and coded as strain number 1 and number 2. The strains were distributed among 679 microbiology laboratories. All laboratories were requested for identification of each unknown microorganism and susceptibility testing of S. pneumoniae against five commonly used antibiotics. RESULTS: Of 679 microbiology laboratories 310 (46%) laboratories participated in the survey and among these, 258 laboratories completely identified S. pneumoniae. About 85% laboratories produced correct susceptibility testing against oxacillin, erythromycin, tetracycline, and vancomycin. Of 310 received responses only 50 laboratories identified H. influenza correctly. The majority of the laboratories did not have the capacity to identification H. influenza. CONCLUSION: Microbiology laboratories in our country are qualified for identification and susceptibility testing of S. pneumoniae. However, majority of laboratories are not qualified for identification of H. influenzae.

Cardiovascular responses to railway noise during sleep in young and middle-aged adults.

The aim of this study was to investigate the effects of nocturnal railway noise on cardiovascular reactivity in young (25.8 +/- 2.6 years) and middle-aged (52.2 +/- 2.5 years) adults during sleep. Thirty-eight subjects slept three nights in the laboratory at 1-week interval. They were exposed to 48 randomized pass-bys of Freight, Passenger and Automotive trains either at an 8-h equivalent sound level of 40 dBA (Moderate) and 50 dBA (High) or at a silent Control night. Heart rate response (HRR), heart response amplitude (HRA), heart response latency (HRL) and finger pulse response (FPR), finger pulse amplitude (FPA) and finger pulse latency (FPL) were recorded to measure cardiovascular reactivity after each noise onset and for time-matched pseudo-noises in the control condition. Results show that Freight trains produced the highest cardiac response (increased HRR, HRA and HRL) compared to Passenger and Automotive. But the vascular response was similar whatever the type of train. Juniors exhibited an increased HRR and HRA as compared to seniors, but there was no age difference on vasoconstriction, except a shorter FPL in seniors. Noise level produced dose-dependent effects on all the cardiovascular indices. Sleep stage at noise occurrence was ineffective for cardiac response, but FPA was reduced when noise occurred during REM sleep. In conclusion, our study is in favor of an important impact of nocturnal railway noise on the cardiovascular system of sleeping subjects. In the limit of the samples studied, Freight trains are the most harmful, probably more because of their special length (duration) than because of their speed (rise time).

Combined effects of noise and shift work on fatigue as a function of age.

The study was conducted to analyse possible interactions between noise and shift work, and fatigue as a function of age. In a large questionnaire survey, we assessed personal and environmental risk factors related to fatigue. Noise exposure at work (L(Aeq, 8hr)) was measured with personal noise dosimetry. The sample included 254 day and shift workers, and was divided into 2 age groups (<40- and >40-year-olds). Noise exposure had a main effect on fatigue. The highest noise exposure resulted in an increase in the fatigue level of older shift workers. The quantity of sleep mainly depended on the type of shift and age. Our data suggest that the most important factor generating fatigue could be related to industrial noise exposure, a factor which seems to aggravate work-related fatigue generated in a synergic manner by shift work and ageing. Senior workers should be prevented from cumulating those occupational stressors.

Evaluation of a new CHROMagar medium for detection of methicillin-resistant Staphylococcus aureus.

Four laboratory methods including, E-test MIC, Oxacillin screen agar, manitol salt agar plus oxacillin and CHROMagar MRSA were compared for detection of methicilin resistant Staphylococcus aureus (MRSA). CHROMagar MRSA had a high sensitivity and specificity comparing to conventional E-test method. Sensitivity and specificity by manitol salt agar was 95 and 100%, respectively, while oxacillin screening agar method had 100% sensitivity and 95% specificity.

Effects of nocturnal railway noise on sleep fragmentation in young and middle-aged subjects as a function of type of train and sound level.

Due to undisputable effects of noise on sleep structure, especially in terms of sleep fragmentation, the expected development of railway transportation in the next few years might represent a potential risk factor for people living alongside the rail tracks. The aim of this study was to compare the effects of different types of train (freight, automotive, passenger) on arousal from sleep and to determine any differential impact as a function of sound level and age. Twenty young (16 women, 4 men; 25.8 years+/-2.6) and 18 middle-aged (15 women, 3 men; 52.2 years+/-2.5) healthy subjects participated in three whole-night polysomnographic recordings including one control night (35 dBA), and two noisy nights with equivalent noise levels of 40 or 50 dB(A), respectively. Arousal responsiveness increased with sound level. It was the highest in S2 and the lowest in REM sleep. Micro-arousals (3-10 s) occurred at a rate of 25-30%, irrespective of the type of train. Awakenings (>10 s) were produced more frequently by freight train than by automotive and passenger trains. Normal age-related changes in sleep were observed, but they were not aggravated by railway noise, thus questioning whether older persons are less sensitive to noise during sleep. These evidences led to the conclusion that microscopic detection of sleep fragmentation may provide advantageous information on sleep disturbances caused by environmental noises.