In this study, the safety education method for preventing human errors effectively was developed, based on the present implementation situation of safety education. The problems of traditional education methods are the following: (1) it is not the main theme to understand the human behavioural trait; (2) discussion is not performed between the teacher and participants; (3) the short-term education effect is demanded. Based on these problems, the following techniques were developed; (1) discussion between an educator and a participant as the main educational method; (2) analyzing the real accident cases and considering the causes and the measures; (3) examining whether a human error existed or not by participating in a simulation session, and considering the generating mechanism of a human error; (4) considering the preventive measures that could be coped with by an individual or not. Furthermore, training using the new method was carried out by an industrial company, and the effect was assessed qualitatively. The participants' change of an understanding to of human errors and the upsurge in motivation to take action was confirmed. The need for future studies was also discussed.

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The criteria set by the Japanese Nursing Association (2013) for improving the conditions of night and shift work of nurses according to the principles recommended by Knauth and Rutenfranz are expected to become a cornerstone of the efforts to improve working conditions for nurses. However, the 16-hour night shift already in place poses practical obstacles spreading the use of an ergonomic 8-hour night shift which would require drastic changes in the current shift systems. Recently, an interim strat egy is instituted by applying a night shift of 12 to 14 hours that allows for naps (90 min) during the shift. Therefore, in this study, we investigated the relationship between the sleep architecture of naps during the night shift working on a 14-hour night shift (19:00-09:00) and that of sleeps preceding the night shift. We used new devices deployed under mattresses to evaluate the sleep architecture (Nemuri monitor; AISIN SEIKI Co., Ltd). The participants were 30 nurses assigned to the night shift in the internal ward. Their average age was 26.7 years. The three nurses assigned to each night shift took their naps in succession, with the first nap (0:00-1:30), the second nap (1:30-3:00) and the third nap (3:00-4:30). We measured the naps for 139 person-days. And we obtained data on sleep during the preceding off night and daytime sleeps just before the night shift through the sleep logs maintained by the subjects.
There were no significant differences in the three nap conditions excepting for Work after sleep onset (p=0.002 between the first nap and the third nap). We found no statistically signifi cant differences for slow-wave sleep perhaps a result of the strain for the nap (e.g. rumination and apprehension) imposed on the nurses by their duties. There was a negative relationship between sleep during the preceding off-night and daytime sleep just before the night shift (p < 0.001, r=-0.3). The participants tended to postpone the bedtime on the off-night before their assigned shift to ensure a long sleep during the daytime before the night shift. On the off-night preceding the day of the assigned night shift, sleep began between 01:00 and 01:59 or between 02:00 and 02:59 in the largest number of participants (26.0% each), whereas it was started after 04:00 in as many as 11.0% of the participants. Nurses, consequently, tended to sacrifice personal life and their sleep schedule to accommodate work duties, since various events, specificity as “Human Care Work”, including any sudden change in patient conditions or procedures related to a deceased patient, might have precluded the nap during night shift.

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The microscopic specimen is used for an evaluation of a metal heat treating process. The surface of the specimen is prepared by hand-held polishing. Long term training is necessary to meet the quality criteria for polished surfaces. The preparation process for a microscopic specimen consists of cutting up, mounting and polishing. The proper polishing technique is acquired through a sort of intuition and long experience. This technique has been conveyed across generations in the form of tacit knowledge, without explication of the knowledge acquired. Thus, training new technicians is a difficult and inefficient process. In this study, we compared the finger force generated by expert and non-expert technicians, and verified the effect of the difference in finger force applied for the polished surface finish. As a result, finger force by the expert was sustained throughout the trial. The expert’s finger force distribution between the thumb and the middle finger was approximately uniform. The polished surfaces of the specimen prepared by the expert was more uniform in roughness.

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In recent years, the systems of working shifts for nurses in Japanese hospitals have rapidly changed from conventional three-shift systems to two-shift systems. This change has been accompanied with a marked increase in the number of 16-hour night shifts, which consist of the evening and night shifts worked in succession. This study investigated the subjective sleepiness in nurses working such long night shifts.
At hospitals where a 16-hour night shift had been introduced, three nurses per ward worked the night shift. Data were collected from a total of 145 nurses working in 9 wards of 8 hospitals for 5 days from Monday to Friday. Workloads were determined by means of actograms and subjectively assessed busyness ratings recorded every 10 minutes time in a budget study. Sleepiness was also evaluated by the time budget study. The mean age of the nurses was 33.6 years (standard deviation 8.9). The actual on-duty hours per night shift including elective overtime amounted to 18.3 hours (standard deviation 0.8). On average, nurses started the shift at 15：34 (standard deviation 33 min) and finished at 9：41 (standard deviation 33 min). Three nurses took a nap at different times during the night shift, starting around 23：00 (the first nap), 1：00 (the second nap), and 3：00 (the third nap).
Actograms and busyness ratings (r=0.907, p<0.001) followed a bimodal course during the night shift, with two peaks at around 18：00 and 7：00. The highest sleepiness was reported at 5： 20 (26.8%), followed by 9：10, 3：10, 0：20 and 0：30. The sleepiness (t [12]=19.65, p<0.001) and busyness ratings (t [12]=24.279, p<0.001) during the night shifts were higher than those during the evening shift. The third nappers had the highest sleepiness than other nappers during working hours until the nap time (p<0.001) and during early morning hours after the nap period (p=0.041).
We conclude that a 16-hour night shift may have certain benefits in maintaining the circadian rhythm for daytime work, since the night shift occurs only once in 5 days and nurses can take a nap during the night shift. However, it also resulted in frequent sleepiness, particularly, in the case of the third nappers, during such a long night shift.

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