Background While work-family conflict (WFC) has been reported to exert adverse effects on workers' health conditions, evidence linking WFC to presenteeism and absenteeism is not only limited in number but also geographically biased.Aims To examine the associations of WFC with health-related presenteeism and absenteeism among Japanese workers.Methods This study was conducted as part of the Japan Epidemiology Collaboration on Occupational Health study in which we used questionnaire information collected from 7766 workers from five worksites. Absenteeism was defined when they took at least half a day off in the past month. Presenteeism, defined as self-rated poor work performance, was assessed on a scale ranging from 10% to 100%, with those reporting 10-60% classified as poor performance. WFC was assessed using eight items (0-16 scores) with participants categorized into quartiles based on the WFC score. A logistic regression model was used to estimate odds ratios and 95% confidence intervals for presenteeism and absenteeism in relation to WFC categories.Results Of the total participants, 16% reported absenteeism and 15% reported presenteeism. Compared to the individuals in the first quartile of WFC (Q1), individuals in the Q2, Q3 and Q4 categories had 1.17 (0.95-1.43), 1.65 (1.44-1.89) and 2.65 (2.17-3.24) higher odds of absenteeism. The corresponding figures for presenteeism were 1.04 (0.79-1.38), 1.31 (1.13-1.53) and 2.13 (1.85-2.45), respectively.Conclusions Work-family conflict was significantly associated with absenteeism and presenteeism among Japanese workers, which underscores the need to acknowledge and accommodate the balance between work and family responsibilities for workplace health promotion.
Adult height may reflect early-life environmental conditions that influence the risk of type 2 diabetes mellitus (DM). While taller height has been linked to lower DM risk, evidence from East Asia remains limited and inconsistent. Given that DM in East Asians often occurs at lower BMI levels, population-specific research is needed. We examined the prospective association between adult height and incident DM in a large Japanese working population, focusing on differences by sex and birth cohort. Data were obtained from annual health checkups of 63,264 workers from 12 companies in Japan, comprising 54,188 men and 9076 women aged 20–64 years at baseline. Participants were classified by quartile of adult height for each sex. DM was defined as either when the participants had glycated hemoglobin (HbA1c) ≥ 6.5
To enhance agricultural productivity, particularly in large-scale operations, a heterogeneous fleet and fields with specific multiday optimal work periods need to be efficiently managed. This complex problem, which combines vehicle routing and scheduling, has not been sufficiently investigated in previous studies. In this study, we investigated this problem by implementing and comparing two fundamentally different heuristics: a reactive, route-first (sequential allocation) method and a constructive, cluster-first (insertion) method. Computational experiments revealed a key tradeoff: the cluster-first method is superior in minimizing the total travel distance, whereas the route-first method excels at reducing the makespan under tight temporal constraints. This study provides clear guidance on selecting the appropriate method based on operational priorities.
This study demonstrates the feasibility and performance of a pilot-scale hybrid membrane-aerated biofilm reactor (MABR) equipped with an innovative gear-structured polyethylene membrane. Over 210 days of continuous operation, the integrated system-comprising an anaerobic tank, a hybrid MABR tank, containing 2-16 cassettes within a membrane module, and an aerobic tank-achieved removal efficiencies of 88 ± 12% for BOD, 40 ± 14% for total nitrogen, and 90 ± 14% for ammonia. The total sludge yield was 0.20 kg-TSS/kg-CODMn, significantly lower than that of conventional activated sludge systems. Spatial and temporal variations in oxygen transfer rate (OTR) and efficiency (OTE) were observed across membrane cassettes. The average OTR ranged from 3.51 to 9.63 g-O₂/(m²·day) and was influenced by operating time and membrane surface area, with lower surface areas enhancing OTR. These results highlight the importance of hydrodynamics and cassette configuration in optimizing oxygen supply. Campaign-based assessments revealed low N₂O emission factors of 0.058% on day 100 (29.2 °C) and 0.074% on day 190 (18.5 °C). At 18.5 °C, N₂O emissions were primarily attributed to the aerobic tank, while contributions from the MABR tank decreased over time, likely due to biofilm maturation. Combined microbial analyses revealed dense populations of ammonia-oxidizing bacteria within the membrane biofilm, dominated by comammox Nitrospira, which likely contributed to the observed low N₂O emissions. Overall, gear-structured membranes promoted resilient biofilm formation, reduced sludge production, and minimized N₂O emissions. These findings provide important insights into the design and operation of sustainable and energy-efficient MABR systems for wastewater treatment.
