Indiana University-Purdue University Indianapolis (IUPUI) / Workers who request a flexible schedule to accommodate their biologically-determined sleep-wake cycle (chronotype) may face prejudice if supervisors perceive them, particularly “night owls”, as lazy or unconscientious. Such bias may be exacerbated in organizational cultures characterized by stability and control. Thus, chronotype bias was examined in a 2 (rigid vs. flexible organizational norms) X 3 (morningness chronotype, eveningness chronotype, educational pursuit/control as reason for a flexible schedule request) online scenario study. Participants were recruited through Amazon Mechanical Turk (N=398) and were instructed to act as managers to decide whether to approve a fictitious employee’s request for a flexible schedule. Organizational culture and reason for schedule request were orthogonally manipulated in the scenarios. Ps completed measures of schedule approval (including an open-ended justification item), beliefs about the employee’s performance (job-specific task performance, contextual performance, personal discipline, and conscientiousness), and manipulation checks, as well as measures of their own chronotype. Ps were less likely to approve a flexible schedule request for employees with chronotype-based requests (both morningness and eveningness) compared to control (educational pursuit/control request). Task performance beliefs mediated the effect. Organizational norms had both a direct and moderating effect on schedule approval, such that approval was higher and chronotype bias was weakened in the flexible norm condition compared to the rigid norm condition. Ps’ own chronotype had no direct or moderating effect on schedule approval. Qualitative content analysis of Ps’ justification for the schedule approval decision revealed that Ps justified their decision on the impact of schedule approval on the organization.

This thesis seeks to examine time in the secondary world fantasies of Patricia A. McKillip. Very little work has been done previously on McKillip, and none examines such a broad range of her works. Taking a strict definition of secondary world, I investigate McKillip’s fantasy books that fit within this parameter to see whether there is a unifying principal behind time, in all its forms, in her work. Although time has been examined in fantasies that are obviously about time, very little has been done in the style of Mark Currie or Paul Riceour, who examine time in books that contain time but do not seem to be about time. I investigate time in terms of an overall chronotope, and argue that this seems to be one of the past. I argue that McKillip’s works and other fantasy books like hers have a grammar of the past, and that everything in their works is influenced, to a degree, by this grammar. Thematically organised chapters examine sixteen of McKillip’s immersive fantasies. The thesis begins with an investigation of the overall chronotope of McKillip’s books and the influence this has on her works. It then examines “active time”: time which is used in an active way to undo and heal wrongs of the past. McKillip’s use of legends to add depth and age to her stories is explored. Her pastoral works, those with a nostalgic connection with nature, are examined. The sometimes counterpoint of the pastoral, cities, are then investigated and found to be places of influenced by time passing in the form of age and political era. Lastly, several of McKillip’s characters are examined to show how time has affected them and affected their interactions with those around them.

Breakfast intake is associated with numerous positive physical and mental health outcomes, yet breakfast skipping remains common in adults. Chronotype and sleep show potential as predictors of breakfast intake; however the existing literature has methodological limitations and fails to examine how psychological mechanisms might explain the relation between sleep and breakfast. The current investigation explored the association of means and variability of sleep behaviors (bedtime, midsleep, sleep duration) as predictors of breakfast intake frequency and high-protein breakfast intake frequency. Additionally, the role of positive and negative affect as mediators in the sleep—breakfast association was examined. Hierarchical regressions and PROCESS parallel mediation models were conducted to assess direct and indirect associations. Variability in bedtime was a significant predictor of breakfast intake frequency, with greater variability associated with less frequent intake. Future work is necessary to examine further the association of sleep and breakfast behaviors, and psychological mechanisms in this relation.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

The circadian system controls 24-hour cycles of behavior and physiology, such as rest-activity and feeding rhythms. The human circadian system synchronizes with, or entrains to, the light/dark cycle (sunrise/sunset) to promote activity and food consumption during the day and rest at night. However, strict work schedules and nighttime light exposure impair proper entrainment of the circadian system, resulting in chronic circadian misalignment. Numerous studies have shown that chronic circadian misalignment results in poor health. Therefore, therapeutic interventions that could shift circadian rhythms and alleviate circadian misalignment could broadly impact public health. Although light is the most salient time cue for the circadian system, several laboratory studies have shown that exercise can also entrain the internal circadian rhythm. However, these studies were performed in controlled laboratory conditions with physically-active participants. The purpose of this study was to determine whether timed exercise can phase advance (shift earlier) the internal circadian rhythm in sedentary subjects in free-living conditions. Fifty-two young, sedentary adults (16 male, 24.3±0.76 yrs) participated in the study. As a marker of the phase of the internal circadian rhythm, we measured salivary melatonin levels (dim light melatonin onset: DLMO) before and after 5 days of timed exercise. Participants were randomized to perform either morning (10h after DLMO) or evening (20h after DLMO) supervised exercise training for 5 consecutive days. We found that morning exercisers had a significantly greater phase advance than evening exercisers. Importantly, the morning exercisers had a 0.6h phase advance, which could theoretically better align their internal circadian rhythms with the light-dark cycle and with early-morning social obligations. In addition, we also found that baseline DLMO, a proxy for chronotype, influenced the effect of timed exercise. We found that for later chronotypes, both morning and evening exercise advanced the internal circadian rhythm. In contrast, earlier chronotypes had phase advances when they exercised in the morning, but phase delays when they exercised in the evening. Thus, late chronotypes, who experience the most severe circadian misalignment, may benefit from exercise in the morning or evening, but evening exercise may exacerbate circadian misalignment in early chronotypes. Together these results suggest that personalized exercise timing prescriptions based on chronotype could alleviate circadian misalignment in young adults.

Die Leistungsfähigkeit vieler kognitiver Funktionen zeigt tageszeitliche Schwankungen, welche auf dem Zusammenspiel der im 2-Prozess-Modell der Schlafregulation beschriebenen Prozes- se basieren: dem homöostatischen Schlafdruck (Prozess S) sowie dem circadianen Schrittma- cher (Prozess C). Darüberhinaus existieren verschiedene Chronotypen, welche oftmals einen synchrony-effect, also eine bessere Leistung zu für sie optimalen Tageszeiten im Vergleich zu nicht-optimalen Tageszeiten, zeigen. In der vorliegenden Arbeit wurde untersucht, in- wieweit die Leistungsfähigkeit der mittels des Attention Network Task (ANT) gemessenen Aufmerksamkeitsfunktionen tonische und phasische Alertness, Orientierung und exekutive Aufmerksamkeit aufgrund homöostatischer und circadianer Faktoren bei extremen Chrono- typen tageszeitabhängige und/oder chronotypabhängige Variationen unter synchronisierten Bedingungen (also einem normalen Tag-Nacht-Rhythmus) mit selbstgewählten Schlafzeiten zeigen. Zu diesem Zweck wurden je 20 ausgeprägte Morgen- bzw. Abendtypen zu fünf ver- schiedenen Uhrzeiten (9:00, 12:00, 15:00, 18:00 und 21:00 Uhr) in randomisierter Reihenfolge getestet. Phasische Alertness, Orientierung sowie die exekutive Aufmerksamkeit zeigten sich bei beiden Chronotypen im Tagesverlauf stabil. Die in einer ähnlichen Studie gefundenen Schwankungen der phasischen Alertness der Morgen-/Neutraltypen sowie der exekutiven Auf- merksamkeit bei beiden Chronotypen konnten nicht repliziert werden, was wahrscheinlich auf eine unterschiedliche Einteilung in Chronotypgruppen sowie ein unterschiedliches Studiende- sign zurückzuführen ist. Möglicherweise kann dies aber auch darauf hinweisen, dass es sich bei der Chronotyp-Dimension auf behavioraler Ebene nicht um ein Kontinuum handelt. Wäh- rend die tonische Alertness bei den Morgentypen gleich blieb, zeigte sich bei den Abendtypen ein synchrony-effect, d.h. sie zeigten eine Verbesserung der Leistung im Tagesverlauf, wobei nicht auszuschließen ist, dass neben der nicht-optimalen circadianen Phase der Abendtypen am Morgen auch sleep inertia sowie partielle Schlafdeprivation zu diesem Verlauf beigetragen haben können. Darüberhinaus zeigten die Morgentypen unabhängig von der Tageszeit eine generell schlechtere Orientierungsfunktion als die Abendtypen, was die Hypothese einer ver- schiedenartigen hemisphärischen Dominanz bei den verschiedenen Chronotypen unterstützt. Die Ergebnisse der vorliegenden Studie unterstützen die These, dass verschiedene kognitive Prozesse selektiv durch homöostatische und circadiane Prozesse moduliert werden, da selbst so ähnliche Funktionen wie die tonische und die phasische Alertness unterschiedliche Ver- läufe zeigen und in einer früheren Studie Schwankungen der phasischen Alertness und der exekutiven Aufmerksamkeit bei moderaten Morgen-/Neutraltypen bzw. moderaten Abendty- pen beschrieben wurden. Ob die unterschiedlichen Ergebnisse der vorliegenden und früherer Studien tatsächliche Unterschiede zwischen verschiedenen Chronotypen reflektieren oder Un- terschieden des jeweiligen Studiendesigns geschuldet sind, ist in weiterführenden Studien zu untersuchen.

Introdução: O horário de realização de atividades, nos seres humanos, pode influenciar fatores fisiológicos, comportamentais e sociais. Podendo interferir, então, em questões relacionadas à atividade física e consumo alimentar. Objetivos: Identificar características acerca da atividade física e alimentação em esportistas que treinavam pela manhã e à noite. Métodos: Foi realizado através da aplicação de questionários (cronotipo, atividade física habitual e recordatório alimentar de vinte e quatro horas) e aferição de medidas antropométricas (peso e altura). Resultados: Foram encontradas correlações positivas entre a matutinidade e a prevalência de indivíduos treinando pela manhã, maior escore total de atividade física, e maior consumo de quilocalorias e proteínas pela manhã. Conclusão: Os achados sugerem que a tipologia circadiana está envolvida com a preferência pela prática de exercícios em determinados turnos, e tendências no consumo energético e proteico, além do nível de atividade física. Mas ainda são necessárias mais pesquisas na crescente área da cronobiologia associada à nutrição e exercícios. / Background: The time of conducting activities, in humans, may influence physiological, behavioral and social factors. And may interfere, then, on physical activity and food intake issues. Objective: Identify characteristics about physical activity and feeding in sportspeople who trained in the morning and the evening. Methods: Was conducted through the use of questionnaires (chronotype, habitual physical activity and twenty-four hours food recall) and anthropometric measurements (height and weight). Results: Positive correlations were found between morningness and morning training, higher total score of physical activity, and higher intake of kilocalories and protein in the morning. Conclusion: The findings suggests that the circadian typology is involved with preference for exercises practicing in certain shifts, and trends in energy and protein intake, beyond the physical activity level. But still more research is needed in the growing area of chronobiology associated with nutrition and exercise.

Introdução: O horário de realização de atividades, nos seres humanos, pode influenciar fatores fisiológicos, comportamentais e sociais. Podendo interferir, então, em questões relacionadas à atividade física e consumo alimentar. Objetivos: Identificar características acerca da atividade física e alimentação em esportistas que treinavam pela manhã e à noite. Métodos: Foi realizado através da aplicação de questionários (cronotipo, atividade física habitual e recordatório alimentar de vinte e quatro horas) e aferição de medidas antropométricas (peso e altura). Resultados: Foram encontradas correlações positivas entre a matutinidade e a prevalência de indivíduos treinando pela manhã, maior escore total de atividade física, e maior consumo de quilocalorias e proteínas pela manhã. Conclusão: Os achados sugerem que a tipologia circadiana está envolvida com a preferência pela prática de exercícios em determinados turnos, e tendências no consumo energético e proteico, além do nível de atividade física. Mas ainda são necessárias mais pesquisas na crescente área da cronobiologia associada à nutrição e exercícios. / Background: The time of conducting activities, in humans, may influence physiological, behavioral and social factors. And may interfere, then, on physical activity and food intake issues. Objective: Identify characteristics about physical activity and feeding in sportspeople who trained in the morning and the evening. Methods: Was conducted through the use of questionnaires (chronotype, habitual physical activity and twenty-four hours food recall) and anthropometric measurements (height and weight). Results: Positive correlations were found between morningness and morning training, higher total score of physical activity, and higher intake of kilocalories and protein in the morning. Conclusion: The findings suggests that the circadian typology is involved with preference for exercises practicing in certain shifts, and trends in energy and protein intake, beyond the physical activity level. But still more research is needed in the growing area of chronobiology associated with nutrition and exercise.

Introdução: O horário de realização de atividades, nos seres humanos, pode influenciar fatores fisiológicos, comportamentais e sociais. Podendo interferir, então, em questões relacionadas à atividade física e consumo alimentar. Objetivos: Identificar características acerca da atividade física e alimentação em esportistas que treinavam pela manhã e à noite. Métodos: Foi realizado através da aplicação de questionários (cronotipo, atividade física habitual e recordatório alimentar de vinte e quatro horas) e aferição de medidas antropométricas (peso e altura). Resultados: Foram encontradas correlações positivas entre a matutinidade e a prevalência de indivíduos treinando pela manhã, maior escore total de atividade física, e maior consumo de quilocalorias e proteínas pela manhã. Conclusão: Os achados sugerem que a tipologia circadiana está envolvida com a preferência pela prática de exercícios em determinados turnos, e tendências no consumo energético e proteico, além do nível de atividade física. Mas ainda são necessárias mais pesquisas na crescente área da cronobiologia associada à nutrição e exercícios. / Background: The time of conducting activities, in humans, may influence physiological, behavioral and social factors. And may interfere, then, on physical activity and food intake issues. Objective: Identify characteristics about physical activity and feeding in sportspeople who trained in the morning and the evening. Methods: Was conducted through the use of questionnaires (chronotype, habitual physical activity and twenty-four hours food recall) and anthropometric measurements (height and weight). Results: Positive correlations were found between morningness and morning training, higher total score of physical activity, and higher intake of kilocalories and protein in the morning. Conclusion: The findings suggests that the circadian typology is involved with preference for exercises practicing in certain shifts, and trends in energy and protein intake, beyond the physical activity level. But still more research is needed in the growing area of chronobiology associated with nutrition and exercise.

We examined the circadian rhythms of locomotor activity in three spider species in the Family Theridiidae under light–dark cycles and constant darkness. Contrary to previous findings in other organisms, we found exceptionally high variability in endogenous circadian period both within and among species. Many individuals exhibited circadian periods much lower (19–22 h) or much higher (26–30 h) than the archetypal circadian period. These results suggest relaxed selection on circadian period as well as an ability to succeed in nature despite a lack of circadian resonance with the 24-h daily cycle. Although displaying similar entrainment waveforms under light–dark cycles, there were remarkable differences among the three species with respect to levels of apparent masking and dispersion of activity under constant dark conditions. These behavioral differences suggest an aspect of chronotype adapted to the particular ecologies of the different species.