Abstract Background Time is the most limited resource in medicine. When unpaid care and domestic work are distributed unevenly by gender, this can alter how physicians work, train, and earn—an international pattern with implications for equity and workforce sustainability. Here, we investigated gender differences in income and daily time allocation for paid work, unpaid care work (housework and child care), and other essential activities. Methods We conducted a cross-sectional web survey of physicians registered with a large Japanese medical portal (m3.com) from January 9 to 31, 2024. Participants were full-time hospital physicians who met the inclusion criteria (n = 2,540; 2,224 men and 316 women). The exposure was physician gender (women vs. men). Outcomes were self-reported daily hours across seven time-use domains—unpaid care work on weekdays and on weekends/holidays (primary), paid work, academic and professional development, commuting, meals and personal care, leisure, and sleep—and personal annual income (≥ ¥15 million vs. < ¥15 million). We estimated adjusted gender differences in time use and the adjusted prevalence ratio for earning ≥ ¥15 million, controlling for key demographic and occupational factors. Results Response and participation rates could not be calculated because the survey vendor did not disclose the sampling denominator. After multivariable adjustment, women spent more hours on unpaid care work than men on both weekdays (1.51 h/day; 95% confidence interval [CI] 1.31 to 1.70) and weekends/holidays (2.35 h/day; 95% CI 1.98 to 2.72). Women also reported fewer hours in paid work, academic and professional development, and leisure. Women were less likely than men to earn ≥ ¥15 million annually (adjusted prevalence ratio 0.65; 95% CI 0.56 to 0.76). Conclusions In this cross-sectional sample of full-time hospital physicians in Japan, substantial gender disparities in income and time use remained after adjustment for major demographic and occupational factors. Universal caregiver supports should be designed to encourage and facilitate men’s participation, to avoid reinforcing gendered divisions of labor.
This paper presents proof-of-concept studies of high-temperature superconductor (HTS) synchronous rotating machines for ship propulsion applications, with a particular focus on rotors based on bulk HTS. It describes a 30 kW, 190 rpm radial-flux motor that uses assemblies of rectangular Gd-Ba-Cu-O bulk superconductors as field poles. To ensure stable magnetization and support operational testing, a field-cooled magnetizing system capable of generating up to 5 T was developed. Over 10 months, the rotor showed strong resistance to load and temperature variations; in particular, the field-pole flux decayed by less than 1% during 369 hours of load operation. By comparison with results from a megawatt-class motor using HTS-1G tape-wound field poles, this study indicates the potential scalability of HTS rotors composed of bulk field-pole modules. The next crucial milestone for the completion of an MW machine system is the application of HTS wires in the armature. The present HTS bulk rotor and the associated robust thermal management, cryogenic systems, and safety features would be a basis for an innovative ship propulsion motor and further progress of maritime transport.
In deep-hole drilling using long drills (L/D >= 40), chip evacuation becomes poor, and step-feed drilling is therefore employed, resulting in reduced machining efficiency. Although the use of high-pressure coolant (HPC) machining technology is expected to improve chip evacuation as well as reduce tool damage, few studies have investigated the effects of applying a high-pressure coolant to deep-hole drilling with long drills, either domestically or internationally. Therefore, this study aimed to propose and experimentally demonstrate the combined use of a high-pressure coolant during drilling in order to achieve high-efficiency and high-precision deep-hole machining (L/D = 40) using a 5-mm-diameter drill. The results that (1) at a cutting speed of 60 [m/min], the flank wear on both cutting edges was significantly greater at a coolant pressure of 0.2 [MPa] than at 20 [MPa], (2) although the axial hole deviation varied with the number of holes, it was smaller at a cutting speed of 90 [m/min] than that at 80 [m/min], and so on, were obtained.
In this study, we combine the Glauber–Lachs formula from quantum optics and the two-component picture for pion production to analyze data on two- and three-pion Bose–Einstein correlation in pp collisions at 7 TeV from the LHCb Collaboration. For the pion exchange function E_ 2B, we chose a dipole form and an inverse one-and-a-half pole form. The extensions are computed in the configuration space of four-dimensional Euclidean space (ξ=√(|r_1-r_2|^2+(t_1-t_2)^2)).
The Dynamic Positioning System is classified into three types: DP class A, B, and C. DP class A vessels hold an overwhelming market share, but it lacks redundancy and is prone to failures. Therefore, in case of failure, there is a possibility of loss in positioning. Herein, we postulated that training Dynamic Positioning Operators (DPOs) for emergencies should mitigate maritime incidents. Accordingly, simulators have been proposed for achieving this objective. Using an experiential approach, nine DPOs were exposed to DPS simulation emergency response training at a lab in Japan. Each participant was given four tasks and a checklist to assist in decision-making to avoid collisions in various scenarios involving marine structures. An analysis of the simulator experiments and outcomes indicated that the length of experience in ship handling and prior training influenced DPOs performance. The study concluded that DPOs should take more effective training to maintain proper positioning for the safe operation of DP vessels.
