Developmental programming of production and reproduction in dairy cows: IV. Association of maternal milk fat and protein percentage and milk fat to protein ratio with offspring's birth weight, survival, productive and reproductive performance and AMH concentration from birth to the first lactation period.

Although the association of maternal milk production with developmental programming of offspring has been investigated, there is limited information available on the relationship of maternal milk components with productive and reproductive performance of the offspring. Therefore, the present study was conducted to analyze the association of maternal milk fat and protein percentage and milk fat to protein ratio with birth weight, survival, productive and reproductive performance and AMH concentration in the offspring. In study I, data of birth weight, milk yield and reproductive variables of offspring born to lactating dams (n = 14,582) and data associated with average maternal milk fat percentage (MFP), protein percentage (MPP) and fat to protein ratio (MFPR) during 305-day lactation were retrieved. Afterwards, offspring were classified in various categories of MFP, MPP and MFPR. In study II, blood samples (n = 339) were collected from offspring in various categories of MFP, MPP and MFPR for measurement of serum AMH. Maternal milk fat percentage was positively associated with birth weight and average percentage of milk fat (APMF) and protein (APMP) and milk fat to protein ratio (FPR) during the first lactation, but negatively associated with culling rate during nulliparity in the offspring (P < 0.05). Maternal milk protein percentage was positively associated with birth weight, APMF, APMP, FPR and culling rate, but negatively associated with milk yield and fertility in the offspring (P < 0.05). Maternal FPR was positively associated with APMF and FPR, but negatively associated with culling rate, APMP and fertility in the offspring (P < 0.05). However, concentration of AMH in the offspring was not associated with MFP, MPP and MFPR (P > 0.05). In conclusion, the present study revealed that maternal milk fat and protein percentage and their ratio were associated with birth weight, survival, production and reproduction of the offspring. Yet it was a preliminary research and further studies are required to elucidate the mechanisms underlying these associations.

Developmental programming of production and reproduction in dairy cows: III. Association of level of maternal milk production with offspring's birth weight, survival, productive and reproductive performance and AMH concentration from birth to the first lactation period.

Although some studies investigated the relationship of dam milk production (DMP) with offspring birth weight and productive performance, limited information is available on the association of level of DMP with reproductive performance in dairy cows. Therefore, the present study was conducted to understand whether dams with various levels of milk production produce offspring with different fertility. In study I, offspring were classified based on the level of DMP into five categories, including DMP1 (dams with <10.00 × 103 kg of 305-day milk production), DMP2 (dams with ≥10.00 × 103 kg and <12.00 × 103 kg of 305-day milk production), DMP3 (dams with ≥12.00 × 103 kg and <14.00 × 103 kg of 305-day milk production), DMP4 (dams with ≥14.00 × 103 kg and <16.00 × 103 kg of 305-day milk production) and DMP5 (dams with ≥16.00 × 103 kg of 305-day milk production). In study I, data of birth weight, milk yield and reproductive variables of 14,536 offspring born to lactating dams and corresponding data of DMP were retrieved. In study II, blood samples (n = 339) were collected from offspring in various categories of DMP for measurement of serum AMH. Offspring were heavier at birth in DMP4 and DMP5 categories than DMP1 and DMP2 categories (P < 0.05). Milk yield of offspring increased as DMP elevated (P < 0.05); however, offspring in DMP1 and DMP2 categories produced higher milk as compared with their dams during primiparity (P < 0.05) whereas offspring in DMP3, DMP4 and DMP5 categories produced less milk as compared with their dams during primiparity (P < 0.05). Milk fat to protein ratio during the first month of lactation was greater in DMP4 and DMP5 categories than DMP1 category (P < 0.05). Offspring of DMP4 and DMP5 categories were inseminated and conceived at younger ages than offspring of DMP1 category during nulliparity (P < 0.05). Calving to conception interval was longer in DMP5 than DMP1 category in primiparous offspring (P < 0.05), but concentration of AMH did not differ among various categories of DMP (P > 0.05). In conclusion, dams with greater level of milk production produced heavier offspring with higher milk yield but worse transgenerational improvement in milk production and diminished reproductive performance, which were seemingly under higher pressure of negative energy balance during the first month of lactation.

Association of prolonged occupational co-exposures to electromagnetic fields, noise, and rotating shift work with thyroid hormone levels.

The purpose of this study was to determine the association of prolonged occupational co-exposure to extremely low-frequency electromagnetic fields (ELF-EMFs), noise, and rotating shift work with the levels of thyroid hormones (triiodothyronine (T3), thyroxine (T4), and thyroid-stimulating hormone (TSH). From 2016 to 2017, we enrolled all male workers without a history of thyroid disorders and followed them until 2020. To measure ELF-EMFs and noise exposures, we calculated the 8-hour equivalent sound pressure levels (Leq) and the 8-hour average of ELF-EMFs, respectively. Shift work schedules involved 8-hr fixed day and 8-hr clockwise 3-rotating night schedules. The participant's thyroid hormone levels were obtained from blood test results in their medical records. The percentage change in the levels of T3, T4, and TSH was estimated by using different mixed-effects linear regression models. The TSH levels were significantly elevated per a 10-dB increment of noise. The levels of T4 hormone were significantly changed per a unit increase in the levels of ELF-EMFs. Compared to the fixed-day workers, we observed workers exposed to shift work had a significantly lower T4 level. For T4 and TSH hormones, we found significant interactions among noise, ELF-EMFs, and shift work variables. In summary, this study warranted that prolonged exposure to ELF-EMFs, noise, and rotating shift work might be associated with thyroid dysfunction.

Developmental programming of production and reproduction in dairy cows: II. Association of gestational stage of maternal exposure to heat stress with offspring's birth weight, milk yield, reproductive performance and AMH concentration during the first lactation period.

Although the negative effect of maternal exposure to heat stress on production and reproduction of offspring has been reported, there are some discrepancies among various studies about which gestational stage is more critical in this regard. Therefore, the present research was conducted to identify during which stage(s) of pregnancy maternal exposure to heat stress would lead to more dramatic decrease in productive and reproductive performance of offspring. To this end, offspring were classified based on the gestational stage they were in utero exposed to heat stress into four categories, including heat stress exposure (HSE) during only the first trimester of gestation (HSE1), HSE during the first and second trimester of gestation (HSE2), HSE during the second and third trimester of gestation (HSE3) and HSE during only the third trimester of gestation (HSE4). In study I, data of birth weight, milk yield and reproductive variables of 11,788 offspring and data of the month they were conceived were retrieved. In study II, blood samples (n = 521) were collected from offspring in various categories of HSE for measurement of serum AMH. Offspring in HSE1 and HSE2 categories were heavier than offspring in HSE3 and HSE4 categories (P < 0.0001). Offspring in HSE1 and HSE3 categories had the lowest and highest milk production, respectively (P < 0.05). First service conception rate was the greatest and worst in HSE1 and HSE4 categories, respectively (P < 0.05). Service per conception and calving to conception interval were greater in HSE2 than HSE4 category (P < 0.05). Concentration of AMH was lower in HSE1 than HSE4 category (P < 0.05). In conclusion, the present study indicated that the early stage of gestation could be a more critical period for the negative impact of in utero heat stress on developmental programming of milk production and ovarian reserves. Yet an evident temporal pattern for the adverse effect of maternal heat stress on developmental programming of reproductive performance in offspring was not found.

Developmental programming of production and reproduction in dairy cows: I. Association of maternal parity with offspring's birth weight, milk yield, reproductive performance and AMH concentration during the first lactation period.

Multiparous dams have been reported to produce offspring with greater fertility and higher AMH concentration, as a marker of ovarian reserves, as compared with nulliparous and primiparous dams. Yet it has remained to be addressed whether this phenomenon can still be true for old multiparous cows which might experience some geriatric changes in their reproductive system. Therefore, the present study was conducted to evaluate the productive and reproductive performance of offspring with different maternal parity. To this end, offspring were classified based on their maternal parities into four categories, including offspring of nulliparous (no previous parity), primiparous (one previous parity), young multiparous (two to six previous parities) and old multiparous (seven or more previous parities) dams. In study I, data of birth weight, milk yield and reproductive variables of 11,788 offspring and data of their maternal parity were retrieved. In study II, blood samples (n = 521) were collected from offspring with various maternal parity for measurement of serum AMH. Birth weight was the lowest in the offspring of nulliparous dams (P < 0.0001) and it was lower in offspring of primiparous and old multiparous dams than offspring of young multiparous dams (P < 0.05). Milk production was the lowest in offspring of old multiparous dams (P < 0.01), and it was lower in offspring of young multiparous dams than offspring of nulliparous and primiparous dams (P < 0.0001). Offspring of old multiparous dams had greater first service conception rate, less services per conception and shorter calving to conception interval than offspring of nulliparous, primiparous and young multiparous dams (P < 0.05). Furthermore, AMH concentration was higher in offspring of old multiparous dams than offspring of nulliparous and primiparous dams (P < 0.05). In conclusion, the present study revealed greater milk production in offspring resulting from dams with lower parity, probably due to the genetic selection for improvement of milk production in dairy cows which imparts the younger generations greater genetic merits for milk production. Reproductive performance, however, was greater in offspring born to dams with higher parity, particularly those born to old multiparous dams, and this phenomenon might be related to their lower milk production and higher AMH concentration.

The potential impact of emotionally loaded stimuli on over/under-estimating neutral situations among power plant control-room operators.

BACKGROUND: Human emotions vary on a contextual basis. The significance of emotions becomes even more salient in Control Room Operators (CROs) in power plants. OBJECTIVE: This study investigated the effects of emotionally loaded pictures on over/underestimating neutral situations. METHODS: Twenty CROs voluntarily enrolled in the present study. Twenty-one blocks were considered, including ten emotionally loaded and 11 neutral blocks. The stimuli were alternatively submitted to subjects in random order. Each block comprised 13 images from the International Affective Picture System (IAPS), which were shown for 5 seconds. Subjects were required to complete the Self-Assessment Manikin (SAM) after exposure to the first and the last neutral blocks, which were identical. RESULTS: Our analyses showed significant differences between IAPS arousal and SAM1 and SAM2 arousal ratings (p SAM1&IAPS = 0.00, p SAM2&IAPS = 0.02). There was no significant relationship between the first and the second arousals, and emotionally loaded images corresponded to no significant difference in terms of valence. CONCLUSION: The findings suggested that the participants overestimated neutral situations compared with IAPS only in arousal level. Furthermore, CROs can still retain their ability to assess neutral situations in the case of viewing emotional stimuli, especially in valence level, at least half an hour after the first rating. A study design with pure negative/positive and high arousal levels may still provide even more significant results.

Independent, modified, and interacting effects of long-term noise, extremely low-frequency electromagnetic fields, and shift work exposures on liver enzymes.

To quantify long-term independent, modified, and interacting effects of noise, extremely low-frequency electromagnetic fields (ELF-EMFs), and shift work exposures on liver enzymes, a four-year repeated measures study was performed among male workers in a thermal power plant industry from 2016 to 2020. The 8-h equivalent sound pressure levels (Leq) were measured at weighting channels of Z, A, and C for octave-band frequencies. The 8-h time-weighted average of ELF-EMFs levels was measured for each participant. Shift work schedule was determined based on job titles, including 3-rotating night shift work and fixed day shift work schedules. The fasting blood samples were taken to determine liver enzymes (AST, Aspartate transaminase; ALT, Alanine transaminase). The percentage change (PC) and 95% confidence interval (CI) of AST and ALT enzymes were estimated by the different bootstrapped-mixed-effects linear regression models. Per 10-dB noise increase, we found a significantly higher PC (95% CI) of AST and ALT (only LAeq) levels in all regression models with the highest changes for LAeq. For the octave-band noise analysis, there was an upward trend from 31.5 Hz to 1 kHz frequencies and a downward trend from 1 to 8 kHz frequencies. Per 1 mG ELF-EMFs increase, we observed a significantly higher PC (95% CI) of AST and ALT enzymes in the main adjusted and the main adjusted + shift work models. The 3-rotating night than fixed day shift workers had a significant PC in the unadjusted model for AST enzyme and the fully adjusted and the main adjusted + ELF-EMFs models for ALT enzyme. Significant negative two-way or/and three-way interaction effects among the noise, ELF-EMFs, and shift work were observed for both AST and ALT enzymes. Our findings indicated long-term noise, ELF-EMFs, and 3-rotating night shift work exposures may be significantly associated with changes in the levels of liver enzymes.

Replacement of the first GnRH by estradiol in the breeding Ovsynch of Double Ovsynch protocol could improve fertility in Holstein dairy cows.

Unlike GnRH, estradiol could induce emergence of a new follicular wave regardless of the size of follicle. Therefore, the present study was conducted to understand whether replacement of the first GnRH by estradiol in the breeding protocol of Double Ovsynch program could enhance fertility. Cows were randomly assigned to two groups, including Double Ovsynch protocol (Control; n = 120) and Ovsynch-estradiol-PGF2α-GnRH (EPG) protocol (Treatment; n = 120). Cows in both groups were subjected to presynchronization Ovsynch. Seven days later, cows in the control group received GnRH, which was followed by PGF2α and GnRH 7 days and 9 days plus 8 h later, respectively. Cows in treatment group received estradiol 7 days after the second GnRH of presynchronization Ovsynch, which was followed by PGF2α and GnRH 7 days and 10 days plus 8 h later, respectively. Cows were subjected to timed AI (TAI) 16 h after final GnRH in both groups. Pregnancy per AI (P/AI) was greater in cows in treatment than control group (64.17 % vs. 44.17 %, respectively; P = 0.02). Cows with a follicle with diameter ≥ 10 mm (F10) at the beginning of EPG in treatment group had greater P/AI than cows without a F10 at the beginning of breeding Ovsynch in control group (P ≤ 0.05). Pregnancy per AI was greater in cows with a CL at the beginning of EPG in treatment group than cows without a CL at the same timepoint in treatment group, and cows with or without a CL at the beginning of breeding Ovsynch in control group (P ≤ 0.05). In conclusion, inclusion of estradiol in Double Ovsynch protocol as a replacement for the first GnRH of breeding Ovsynch could improve fertility, particularly in cows with a CL at the initiation of EPG.

Evidence that elevation of maternal somatic cell count could lead to production of offspring with inferior reproductive and productive performance in dairy cows during the first lactation period.

Although the effect of mastitis on reproduction and production of lactating dairy cows has been vastly studied, little information is available about the association of maternal udder health status with offspring reproduction and production. Therefore, the present research was conducted to study the association between maternal average monthly somatic cell count (SCC) with reproduction, anti-Müllerian hormone (AMH) concentration, udder health status and milk production in the offspring. Based on maternal average monthly SCC (MSCC), offspring were classified into five categories including MSCC1 (SCC <200,000; n = 3005), MSCC2 (200,000 ≤ SCC <400,000; n = 252), MSCC3 (400,000 ≤ SCC <600,000; n = 103), MSCC4 (600,000 ≤ SCC <800,000; n = 40) and MSCC5 (SCC ≥800,000; n = 61). Data associated with reproduction, production and udder health status of offspring were retrieved from the herd database. In addition, blood samples were collected from a subset of offspring (n = 136) for measurement of serum AMH, as a reliable marker of ovarian reserves. Offspring in MSCC5 category had more services per conception and longer calving to conception interval than offspring in MSCC1 and MSCC2 categories (P < 0.05). The average number of SCC and risk of clinical mastitis in the offspring were not associated with MSCC (P > 0.05). But offspring in MSCC5 category produced less milk, fat and protein than offspring in MSCC1 category (P < 0.05). In addition, AMH concentration was lower in MSCC5 than MSCC1 category (P < 0.05). In conclusion, the present study showed that elevated maternal average monthly SCC could culminate in birth of offspring with inferior reproductive performance, smaller size of ovarian reserves and lower level of milk production during the first lactation period.

Evidence that Murciano-Granadina does with longer anogenital distance are more fertile and prolific and produce heavier and male-biased litters.

Anogenital distance (AGD) is related to fertility in cows, but there is little information on the association of AGD and reproduction in does. Therefore, the present study was conducted to assess the relationship between AGD and reproductive variables in Murciano-Granadina does. AGD was measured as the distance between anus and clitoris and does (n = 578) were divided into two categories of AGD, including short AGD (AGD ≤ median of AGD in studied does; n = 313) and long AGD (AGD > median of AGD in studied does; n = 265). Data of reproductive variables were retrieved from the herd database and were analyzed using multivariable statistical models, in which the potential confounding factors were included. AGD data were not normally distributed (3.78 ± 0.02 cm) and ranged from 2.70 to 5.10 cm. AGD was longer in multiparous and primiparous does than nulliparous does (P < 0.0001), and was positively associated with age and body weight (P < 0.0001). The risk of pregnancy and kidding, litter size, fecundity, proportion of male offspring and birth weight of kids were higher in long AGD does than short AGD does (P < 0.05). But abortion risk did not differ between does with long and short AGD (P > 0.05). In conclusion, the present study revealed that AGD had individual variation among Murciano-Granadina does, and does with long AGD were more fertile and more likely to produce larger, heavier and male-biased litters as compared with does with short AGD.

The long-term effects of exposure to noise on the levels of thyroid hormones: A four-year repeated measures study.

Animal studies have suggested that noise exposure can be associated with changes in the levels of thyroid hormones. However, no evidence is available that quantified this effect on humans. This study aimed to quantify the long-term effects of exposure to noise and its different frequencies on thyroid hormone levels. A four-year repeated measures study was performed among male workers of a thermal power plant industry from 2016 to 2020. Overall, 1032 observations were examined. To determine exposure to noise for each participant, the 8-hour equivalent sound pressure levels (Leq) were measured at weighting channels of Z, A, and C for an octave-band including low (31.5, 63, 125 Hz), middle (250,500, and 1000 Hz), and high (2, 4, 8 kHz) frequency noises. The fasting blood samples were also taken to determine thyroid hormone levels (TSH, Thyroid-stimulating hormone; T4, Thyroxine; T3, Triiodothyronine). The mixed-effects linear regression was applied to specify the percent changes in the levels of thyroid hormones. The prevent changes (95% confidence interval) of T4, T3, and TSH levels per a 10-dB increase in Leq based on the full adjusted model were estimated -0.90 (-1.68, -0.11), -0.70 (-1.44, 0.05), and 3.94 (0.58, 7.40), respectively. The highest percent changes in the T4 and TSH hormones were identified at 500 Hz (percent change = -1.08 and 95% CI = -1.93, -0.23) and with little difference at 1 (percent change = 4.73 and 95% CI = 0.91, 8.70) and 2 kHz (percent change = 4.72 and 95% CI = 1.13, 8.52) frequencies, correspondingly. Our findings indicated that long-term noise exposure may be associated with changes in the levels of thyroid hormones. Although more studies are warranted, noise-induced thyroid dysfunction may play a significant role in the biological pathways of the effects of noise on the human body.

Assessment and virtual redesign of a manual handling workstation by computer-aided three-dimensional interactive application.

BACKGROUND: Manual handling of bags which imposes frequent forces and stresses on body parts is a common task that many workers have to perform every day. The present study aimed to assess the postural risk and imposed forces due to manual handling and loading of sugar bags. METHODS: This study was conducted on male warehouse workers of a sugar manufacturing plant. Rapid upper limb assessment (RULA) was used to assess the risks of awkward postures and computer-aided three-dimensional interactive application to estimate the forces and moments. RESULTS: RULA final scores were estimated to be 7 and 3 before and after the virtual redesign, respectively. Postures B and E obtained the highest compression forces and moments. The compression forces were higher than the action limit (AL) in all postures before the redesign and exceeded the maximum permissible limit (MPL) in posture E. After the redesign, these forces were reduced below the AL and MPL. Moreover, the shearing forces were lower than the AL and MPL in all postures. CONCLUSIONS: The main risk factors were heavy weight and poor control of sugar bags. Virtual redesign can diminish bending and twisting postures, and, therefore, some resulting forces and moments.

Effects of diets supplemented by fish oil on sex ratio of pups in bitch.

The present study was conducted to evaluate the effect of fish oil supplementation prior to mating on secondary sex ratio of pups (the proportion of males at birth) in bitches. Sixty five bitches (German Shepherd, n = 35; Husky, n = 30) were enrolled in the study. Bitches (140-150 days post-estrus) were given 2% per dry matter intake palm oil and fish oil in the control (n = 33) and treatment (n = 32) groups, respectively. To induce estrus, bitches were received equine chorionic gonadotropin (eCG) administration (50 IU kg(-1)) 30 days after nutritional supplementation followed by human chorionic gonadotropin (hCG) administration (500 IU per dog) seven days later. Bitches were introduced to dogs of the same breed after hCG administration. The weight of bitches was increased over time (p < 0.05), but their weight change was not different between two groups (p > 0.05). The mating rate, pregnancy rate and litter size were not influenced by treatment and breed. Secondary sex ratio was higher in the treatment (105/164; 64.00%) than in the control (68/147; 46.30%) group (p < 0.05; adjusted odds ratio = 2.068). Moreover, secondary sex ratio was higher in Husky bitches (88/141; 62.40%) compared to German Shepherd (85/170; 50.00%; p < 0.05; adjusted odds ratio = 1.661). In conclusion, the present study showed that inclusion of fish oil in the diet of bitches prior to mating could increase the proportion of male pups at birth. In addition, it appears that there might be variation among dog breeds with regard to the sex ratio of offspring.

Androgen receptor blockade using flutamide skewed sex ratio of litters in mice.

Maternal testosterone has been indicated to affect sex ratio of offspring. The present study was conducted to elucidate the role of androgen receptor in this regard by blockade of androgen receptor using flutamide in female mice. Mice were randomly assigned to two experimental groups. Mice in the control (n = 20) and treatment (n = 20) groups received 8 IU equine chorionic gonadotropin (eCG) followed by human chorionic gonadotropin (hCG) injection (8 IU) 47 hr later. In addition, mice in the control and treatment groups received four injections of ethanol-saline vehicle and flutamide solution (2.50 mg), respectively, started from 1 hr before eCG injection until hCG injection at 12-hr intervals. Conception rate was not different between the treatment (18/20: 90.00%) and control (19/20: 95.00%) groups (p > 0.05). Litter size was higher in the treatment (8.22 ± 0.26) than control (7.21 ± 0.28) group (p < 0.05). Male sex ratio was lower in the flutamide-treated mice (67/148: 45.30%) as compared with the untreated ones (80/137: 58.40%; odds ratio = 1.69; p < 0.05). In conclusion, the results showed that androgen receptor blockade could skew sex ratio of offspring toward females implying that the effect of testosterone on sex ratio might be through binding to androgen receptor. In addition, the blockade of androgen receptor using flutamide appeared to enhance litter size.

Correlation between Driver Subjective Fatigue and Bus Lateral Position in a Driving Simulator.

BACKGROUND: Driver fatigue as a leading cause of death in the transportation industry can impair the driving performance in long-distance driving task. Studies on the links of driver subjective fatigue and the bus lateral position are still an exploratory issue that requires further investigation. This study aimed to determine the correlation between the driver subjective fatigue and the bus lateral position in a driving simulator. METHODS: This descriptive-analytical research was conducted on 30 professional male bus drivers participated in a two-hour driving session. The driver subjective fatigue was assessed by the Fatigue Visual Analogue Scale (F-VAS) at 10-min intervals. Simultaneously, the performance measures of lane drifting as the mean and standard deviation of the bus lateral position (SDLP) were calculated during the simulated driving task. Descriptive statistics and the Spearman correlation coefficient were used to describe and analyze the data. RESULTS: Fatigue levels had an increasing trend as the time-on-task of driving increased. Time-on-task of driving had the greatest effect on the fatigue self-evaluation (r = 0.605, p < 0.0001). The results showed a significant correlation between fatigue self-evaluation and bus lateral position (r = 0.567, p < 0.0001). CONCLUSION: As the time of driving increased, driving performance was affected adversely, as shown by the increase in the SDLP. Even so, the effect of individual differences on driving performance should not be overlooked. This work concludes that predicting the state of a driver fatigue based on the group mean data has some complications for any application.

Presenting a model for dynamic facial expression changes in detecting drivers' drowsiness.

Drowsiness while driving is a major cause of accidents. A driver fatigue detection system that is designed to sound an alarm, when appropriate, can prevent many accidents that sometime leads to the loss of life and property. In this paper, we classify drowsiness detection sensors and their strong and weak points. A compound model is proposed that uses image processing techniques to study the dynamic changes of the face to recognize drowsiness during driving.

Detecting Driver Mental Fatigue Based on EEG Alpha Power Changes during Simulated Driving.

BACKGROUND: Driver fatigue is one of the major implications in transportation safety and accounted for up to 40% of road accidents. This study aimed to analyze the EEG alpha power changes in partially sleep-deprived drivers while performing a simulated driving task. METHODS: Twelve healthy male car drivers participated in an overnight study. Continuous EEG and EOG records were taken during driving on a virtual reality simulator on a monotonous road. Simultaneously, video recordings from the driver face and behavior were performed in lateral and front views and rated by two trained observers. Moreover, the subjective self-assessment of fatigue was implemented in every 10-min interval during the driving using Fatigue Visual Analog Scale (F-VAS). Power spectrum density and fast Fourier transform (FFT) were used to determine the absolute and relative alpha powers in the initial and final 10 minutes of driving. RESULTS: The findings showed a significant increase in the absolute alpha power (P = 0.006) as well as F-VAS scores during the final section of driving (P = 0.001). Meanwhile, video ratings were consistent with subjective self-assessment of fatigue. CONCLUSION: The increase in alpha power in the final section of driving indicates the decrease in the level of alertness and attention and the onset of fatigue, which was consistent with F-VAS and video ratings. The study suggested that variations in alpha power could be a good indicator for driver mental fatigue, but for using as a countermeasure device needed further investigations.

Determination of Job Stresses and Their Consequences in Drivers in Ilam.

BACKGROUND: Human factors cause 60-70 percent of automobile accidents. Everything related to people that is involved in and interacting with a system is considered to be a human factor. These factors can be psychological, biological, or social, and all of them can affect drivers' behaviors. Therefore, one of the negative and unfavorable effects of these factors is that they cause accidents. According to previous research, increases in the job stresses result in increases in the incidence of car accidents. Drivers who feel stressed often do not to observe the rules, and they may not even notice the warning signs. By measuring the job stress among drivers and its adverse effects, this research aimed to provide an appropriate managerial solution to reduce these problems. METHODS: The sample in this descriptive-analytical study consisted of 250 drivers who were selected and investigated. A job stress questionnaire was used as a means for collecting data. Health conditions were assessed by referring to clinical documents provided for the drivers. Accident data were included in the study using accident-related documentation. Two hundred and fifty drivers from Ilam, Iran participated and were analyzed in this study. This research is a cross-sectional study that was performed by dossiers and personal memoirs. Data were analyzed by SPSS16 and the chi-squared test. RESULTS: The study showed that the main factors that cause medium- to high-level stress are the physical environment, workload and ambiguity of duties. It also showed that the incidence and severity of accidents increased as stress levels increased. CONCLUSION: This study shows high prevalence of job stress amongst drivers in Ilam. The main causes of the prevalence of stress among drivers in Ilam City are physical environment, workload and ambiguity of duties, responsibility.

Investigation of Occupational Stress and its Relationship with the Demographic Characteristics of Workers in Ilam, Iran.

BACKGROUND: Workers are more susceptible to stress disorder for several reasons. The aim of this study was to investigate occupational stress among workers and other personnel at the ZardjinBaft Workshop in Ilam, Iran, and to examine the relationship between occupational stress and several parameters, such as age, gender, marital status, educational level, work experience, tobacco use, body mass index (BMI), and the type of work. METHOD: This was a descriptive, cross-sectional study that was performed in June 2010. The sample population that was studied consisted of all of the workers and other personnel (130 people) at ZardjinBaft Workshop in Ilam, Iran. They were studied using Cooper's standard questionnaire for stress in the work environment, and we examined the relationship between stress, as the dependent variable, and the eight independent variables mentioned in the Abstract. RESULTS: In the sample population that was studied, severe stress was not observed in most of the sections of the workshop. In addition, using the analysis of variance test (ANOVA), no significant relationship was observed between the average degree of stress and the average demographic characteristics. However, the average stress level had significant relationships with the level of education, work experience, and the type of work, suggesting that stress increases as the level of education increases. In addition, in the beginning and early years of employment, medium levels of stress were observed, and the prevalence of stress decreased after the first 10 years of employment. In addition, workers in the ventilation section of the factory had the highest stress levels. The fear of losing their jobs was the main factor that caused stress among the workers at ZardjinBaft Workshop in Ilam. CONCLUSION: We suggest that managers consider the high importance of stress in the work environment. They should be able to recognize when workers are stressed and offer them assistance and training. They also can eliminate the factors that cause stress in the work environment by taking preventive action. In parallel, workers should try to interact well with their managers and talk to her or him about the conditions of their jobs.