「労働科学」最新号
労働科学 87巻4号（2011年）
87巻 4号
小山秀紀，鈴木一弥，酒井一博
トラックドライバーの勤務条件と疲労・睡眠（第２報）―長距離トラックドライバーの疲労とその関連要因の分析―
労働科学，87(4)，121～135，（2011）
本研究では長距離トラックドライバーの疲労とその関連要因を検討した。分析の結果，長時間運転，睡眠不足，休日不足，運転中の休憩・仮眠の不足，時間切迫，および荷扱いの負担と疲労の間に有意な関連を認めた。キャビンの睡眠環境や会社の設備・環境への不満，歩合給への不満と疲労の間に有意な関連を認めた。健康不安，食事習慣，運動不足と疲労の間に有意な関連を認めた。共分散構造分析の結果より，睡眠状況が疲労･健康状態に直接的に影響し，運転状況と組織要因である職場状況が睡眠状況を介して疲労･健康状態に影響することが示された。（図1,表12） （自抄）
キーワード：長距離トラックドライバー；長時間運転；睡眠不足；疲労；職場環境改善
Hideki OYAMA, Kazuya SUZUKI, Kazuhiro SAKAI
Working Conditions, Fatigue, and Sleep of Truck Drivers (2nd report): An Analysis of Cases of Fatigue and Related Factors in Long-haul Truck Drivers
THE JOURNAL OF SCIENCE OF LABOUR，87（4），121～135，（2011）
The purpose of this study was to examine cases of increased fatigue and related factors in 103 long-haul truck drivers. The results showed that about 40 percent of long-haul truck drivers experienced fatigue due to work. The following factors were found to be significantly related to increased fatigue: (1) long driving hours, sleep deprivation, lack of holidays, lack of rest periods and naps between drives, time-related pressure, and work load; (2) dissatisfaction with company equipment and sleeping conditions in the truck’s cabin; (3) dissatisfaction with performance-based pay; (4) poor health; and (5) lack of vegetables, deviation of meals, erratic eating habits, and lack of exercise as aspects of the individuals lifestyle. The results analyzed through structural equation modeling showed that sleeping conditions had a direct influence on the degree of fatigue and health states. Further, driving conditions and organizational conditions as background factors were found to have an indirect influence on the work-related fatigue and health states.
key Words：Long-haul truck drivers；Long driving hours；Lack of sleep；Fatigue；Work environment improvement
外山尚紀
日本における石綿の定義と建材等製品中の石綿含有分析の課題
労働科学，87(4)，136～156，（2011）
日本における建材等の石綿含有の分析方法はJIS A 1481が利用されているが、それは諸外国の方法と異なる方法を採用しており、精度の不十分さが指摘されることがある。本研究では日本、米国、英国、国際標準の建材製品中の石綿含有有無の分析方法を比較検討した。JIS法は国際標準などの方法と比較して石綿の定義が異なる。国際標準などでは石綿の定義として石綿特有の微細な繊維構造を意味する石綿様形態を必須としているのに対して、JIS法では石綿の形態的な定義をアスペクト比３以上としている。この定義の違いが分析方法と分析結果に影響を及ぼしており、JIS法はISO法などと異なる分析結果を導く可能性がある。
（図10，表1） （自抄）
キーワード：石綿；分析；定義；石綿含有製品；石綿様形態
Naoki TOYAMA
Issues on Definition of Asbestos and Asbestos Analytical Method for Asbestos Containing Materials in Japan
THE JOURNAL OF SCIENCE OF LABOUR，87（4），136～156，（2011）
It is important to take proper and rational countermeasures to prevent asbestos exposures of the public from existing asbestos-containing materials. The first important step towards an effective asbestos control is the implementation of an appropriate analytical method for asbestos-containing materials. In Japan, the JIS A 1481 method has been the only legally-acceptable asbestos analysis method since 2006. The JIS method uses a combination of X-ray diffractometry (XRD) and dispersion-staining phase contrast microscopy (DS-PCM) to analyze bulk samples of suspect asbestos-containing materials. The JIS approach is completely different from the ISO/DIS22262-2 analytical method, which is soon to be the international standard for asbestos analyses. Unfortunately, the JIS analytical methodology has repeatedly raised concerns about the accuracy of the analysis based on the JIS method. This study reviews the different definitions of asbestos used in both the JIS and ISO analytical methods; compares the respective effectiveness of each analytical method; and, discusses the accuracy of the JIS method in comparison with that of the ISO method. The JIS method has possibility to lead to analytical results different from those of the ISO method because of the difference in the definition of asbestos and in analytical methods.
Key Words: Asbestos; Analysis; Definition; Asbestos containing materials; Asbestiform
木村 亨
従業員の職務満足と企業業績
労働科学，87（4），157～168，（2011）
製造業70社の従業員約1,800人の職務満足を調べた。景気・為替などの外的要因の変化の影響を除くため,この中から機械22社,化学14社,医薬13社を選び,職務満足調査時ならびに調査前・調査後の対売上高営業利益率を調べ,職務満足との相関を求めた。その結果,職務満足調査前の利益率と職務満足は相関性がなく,調査時および調査後の利益率と職務満足との間には相関性が認められた。職務満足の調査が1時期のみであり調査対象の会社数も十分でないため,この結果から結論を下すことはできないが,従業員の職務満足は企業業績に寄与すると推定できる。このことから,職務満足を高めることは業績と従業員のwell-being両立の手段になり得ると考えられる。
（図2,表5） （自抄）
キーワード : 職務満足 ; 企業業績 ; 対売上高営業利益率
Toru KIMURA
Causal Relationship between Job Satisfaction and Organizational Performance
THE JOURNAL OF SCIENCE OF LABOUR，87（4），157～168，（2011）
An investigation of job satisfaction was conducted by administering a questionnaire to about 1800 white-collar workers at 70 companies. The business performance of the companies as measured by the operating profit ratio in three different periods, before, during and after the survey, was ascertained based on published information. To avoid the influence of business fluctuations and exchange rates, the companies were classified in three groups, machinery, chemical and pharmaceutical, and the correlation coefficient between job satisfaction and the operating profit ratio was calculated for each industry.
The results of data analysis revealed that job satisfaction was significantly correlated with the operating profit ratio both during and after the survey period. However, job satisfaction was not correlated with the profit ratio before the survey. These findings suggest that job satisfaction is not the result of the business performance, and that higher job satisfaction results in improved organizational performance.
Key Words : Job satisfaction ; Organizational performance ; Operational profit ratio