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Nicole Lovato,1 Michelle A Short,2 Gorica Micic,3 Rachel M Hiller,4 Michael Gradisar3 1Adelaide Institute for Sleep Health: A Flinders Centre of Research Excellence, Repatriation General Hospital, Flinders University, 2Centre for Sleep Research, University of South Australia, 3School of Psychology, Flinders University, Adelaide, SA, Australia; 4Department of Psychology, University of Bath, North East Somerset, UK Objective: The prospective, bidirectional relationship between sleep disturbance and depressed mood was assessed in a school-based sample of adolescents. Method: One hundred and thirty-eight Australian adolescents (mean age time 1 =15.69, standard deviation =0.92; 64% male) completed questionnaires to assess sleep parameters and depressed mood, on two occasions over 1 year. Results: Cross-sectional associations were observed between depressed mood and sleep duration, as well as wakefulness in bed. Prospective analyses revealed depressed mood predicted less total sleep time on school nights and a longer latency to sleep onset on weekends 1 year later. There was no prospective support for sleep predicting later depressed mood. Conclusion: Contrary to prediction, our results suggest in this case that depressed mood may act as a precursor to poor sleep rather than the converse. Keywords: adolescence, sleep disturbance, school-based, prospective, depressive symptoms

Objectives: To assess differences relating to circadian preference in objectively measured sleep patterns from childhood to adolescence over a 9-year period. We hypothesized there is developmental continuity in sleep timing and duration according to circadian preference. Study design: Young participants (N = 111, 65% girls) from a community-based birth cohort underwent sleep actigraphy at mean ages 8.1 (SD = 0.3), 12.3 (SD = 0.5), and 16.9 (SD = 0.1) years. A short version of Morningness-Eveningness Questionnaire was administered in late adolescence. At each follow-up, sleep midpoint, duration, wake after sleep onset, sleep efficiency, and weekend catch-up sleep were compared between those reporting morning, intermediate, and evening preferences in late adolescence. Results: Mixed model analyses indicated that sleep timing was significantly earlier among morning types compared with evening type at all ages (P values

Michelle A Short,1,2 Michael Gradisar,1 Leon C Lack,1 Helen R Wright,1 Alex Chatburn21School of Psychology, Flinders University, 2Centre for Sleep Research, University of South Australia, Adelaide, South Australia, AustraliaBackground: In research and clinical contexts, parent reports are often used to gain information about the sleep patterns of their adolescents; however, the degree of concordance between parent reports and adolescent-derived measures is unclear. The present study compares parent estimates of adolescent sleep patterns with adolescent self-reports from surveys and sleep diaries, together with actigraphy.Methods: A total of 308 adolescents (59% male) aged 13–17 years completed a school sleep habits survey during class time at school, followed by a 7-day sleep diary and wrist actigraphy. Parents completed the Sleep, Medical, Education and Family History Survey.Results: Parents reported an idealized version of their adolescent's sleep, estimating significantly earlier bedtimes on both school nights and weekends, significantly later wake times on weekends, and significantly more sleep than either the adolescent self-reported survey, sleep diary, or actigraphic estimates.Conclusion: Parent reports indicate that the adolescent averages a near-optimal amount of sleep on school nights and a more than optimal amount of sleep on weekends. However, adolescent-derived averages indicate patterns of greater sleep restriction. These results illustrate the importance of using adolescent-derived estimates of sleep patterns in this age group and the importance of sleep education for both adolescents and their parents.Keywords: concordance, parent, sleep, sleep measurement, survey, actigraphy

We investigate the potential benefits of introducing meeting points in a ride-sharing system. With meeting points, riders can be picked up and dropped off either at their origin and destination or at a meeting point that is within a certain distance from their origin or destination. The increased flexibility results in additional feasible matches between drivers and riders, and allows a driver to be matched with multiple riders without increasing the number of stops the driver needs to make. We design and implement an algorithm that optimally matches drivers and riders in large-scale ride- sharing systems with meeting points. We perform an extensive simulation study to assess the benefits of meeting points. The results demonstrate that meeting points can significantly increase the number of matched participants as well as the system-wide driving distance savings in a ride-sharing system.

Although adolescents often experience insufficient and/or poor sleep, sleep variables such as total sleep time do not account for individuals’ sleep need and sleep debt and may therefore be an inadequate representation of adolescents’ sleep problems and its daytime consequences. This problem can be overcome by using the Chronic Sleep Reduction Questionnaire (CSRQ), an assessment tool that measures symptoms of chronic sleep reduction and therefore accounting for sleep need and sleep debt. The present study aims at developing an English version of the CSRQ and assesses the reliability and validity of the Dutch and the English CSRQ version. The CSRQ was administered in large Dutch (n = 166, age = 15.2 ± 0.57 years, 28% male) and Australian (n = 236, age = 15.5 ± 0.99 years, 65% males) samples. Subjective sleep variables were measured with surveys and sleep diaries of five school nights. Additionally, sleep of the same five nights was monitored with actigraphy. Both CSRQ versions showed good psychometric properties concerning their reliability (Dutch: α = 0.85; English: α = 0.87) and validity as the same overall structure of the two CSRQ versions and significant correlations with subjective and objective sleep variables were found. School grades were related to chronic sleep reduction, whereas the relationship between grades and other sleep variables was weak or absent. These results highlight the idea that chronic sleep reduction may be a better indicator of adolescents’ insufficient and/or poor sleep than other sleep variables such as total sleep time.