The impact of changing work schedules on American firefighters’ sleep patterns and well-being

Across the nation, fire departments are adopting the 48/96 work schedule, in which firefighters work 48 consecutive hours with the following 96 hours off. Our study objective was to explain and quantify the impact of switching from the Kelly schedule to the 48/96 schedule by measuring changes in sleep, feelings of daytime function, as well as perceptions of professional and personal well-being for American firefighters. Sleep diaries and self-reported surveys were administered to firefighters at an urban fire department. Sleep diaries measuring the number of hours slept and feelings of refreshment were compared one month before and four months after implementation of the 48/96 schedule. The self-reported surveys measured sleepiness levels via the Epworth Sleepiness Scale. Secondary study objectives included changes in professional and personal well-being time for personal schedules, satisfaction, and health habits before and after the 48/96 schedule was implemented. The 59 firefighters included in the study reported an increase in sleep on-shift after the new schedule implementation (5.8 to 6.6 hours/night, p < 0.001). Participants also reported increased feelings of refreshment on days off (p < 0.001) and decreased daytime sleepiness (p < 0.001). We also found a general trend of improved perceptions of satisfaction, less shift interference with personal schedules and decreased feelings of burnout. American firefighters appeared to benefit from a 48/96 schedule, with short-term improvements in sleep patterns, feelings of burnout, and time for personal schedules

The Computational Complexity of Generating Random Fractals

In this paper we examine a number of models that generate random fractals. The models are studied using the tools of computational complexity theory from the perspective of parallel computation. Diffusion limited aggregation and several widely used algorithms for equilibrating the Ising model are shown to be highly sequential; it is unlikely they can be simulated efficiently in parallel. This is in contrast to Mandelbrot percolation that can be simulated in constant parallel time. Our research helps shed light on the intrinsic complexity of these models relative to each other and to different growth processes that have been recently studied using complexity theory. In addition, the results may serve as a guide to simulation physics.Comment: 28 pages, LATEX, 8 Postscript figures available from [email protected]

Rethinking the definition of major trauma: The need for trauma intervention outperforms Injury Severity Score and Revised Trauma Score in 38 adult and pediatric trauma centers

BACKGROUND Patients\u27 trauma burdens are a combination of anatomic damage, physiologic derangement, and the resultant depletion of reserve. Typically, Injury Severity Score (ISS) \u3e15 defines major anatomic injury and Revised Trauma Score (RTS) \u3c7.84 defines major physiologic derangement, but there is no standard definition for reserve. The Need For Trauma Intervention (NFTI) identifies severely depleted reserves (NFTI+) with emergent interventions and/or early mortality. We hypothesized NFTI would have stronger associations with outcomes and better model fit than ISS and RTS. METHODS Thirty-eight adult and pediatric U.S. trauma centers submitted data for 88,488 encounters. Mixed models tested ISS greater than 15, RTS less than 7.84, and NFTI\u27s associations with complications, survivors\u27 discharge to continuing care, and survivors\u27 length of stay (LOS). RESULTS The NFTI had stronger associations with complications and LOS than ISS and RTS (odds ratios [99.5% confidence interval]: NFTI = 9.44 [8.46-10.53]; ISS = 5.94 [5.36-6.60], RTS = 4.79 [4.29-5.34]; LOS incidence rate ratios (99.5% confidence interval): NFTI = 3.15 [3.08-3.22], ISS = 2.87 [2.80-2.94], RTS = 2.37 [2.30-2.45]). NFTI was more strongly associated with continuing care discharge but not significantly more than ISS (relative risk [99.5% confidence interval]: NFTI = 2.59 [2.52-2.66], ISS = 2.51 [2.44-2.59], RTS = 2.37 [2.28-2.46]). Cross-validation revealed that in all cases NFTI\u27s model provided a much better fit than ISS greater than 15 or RTS less than 7.84. CONCLUSION In this multicenter study, NFTI had better model fit and stronger associations with the outcomes than ISS and RTS. By determining depletion of reserve via resource consumption, NFTI+ may be a better definition of major trauma than the standard definitions of ISS greater than 15 and RTS less than 7.84. Using NFTI may improve retrospective triage monitoring and statistical risk adjustments. LEVEL OF EVIDENCE Prognostic, level IV