Virtually nothing is known about how internal circadian clocks interact with daily environmental cycles in nature. Previous work has shown that temperature and light are both able to successfully entrain (synchronize) circadian rhythms in eclosion (adult emergence) and locomotor activity in Sarcophaga crassipalpis when applied independently. However, much less work has been done to evaluate the relative strength of these Zeitgebers (time cues) when applied simultaneously. In nature, light and temperature cycles generally maintain a fixed relationship with one another, with peak soil and air temperature occurring about three hours after peak brightness each day. By manipulating the relationship between these Zeitgebers this project aims to evaluate the effects of conflicting environmental information on eclosion and locomotor activity rhythms in S. crassipalpis. We measured locomotor and eclosion activity under three temperature/light cycle regimes: 1) in-phase temperature and light cycles, with light and thermophase (warm-period) onset occurring simultaneously, 2) thermophase-delayed, beginning six hours after the onset of photoperiod (light-period), or 3) out-of-phase, with the beginning of photophase corresponding to the end of thermophase. In all experiments, eclosion times are very close to thermophase onset, while locomotor activity does not always hold the same phase position. In fact, in the out-of-phase experiment, locomotor activity is almost entirely synchronized with photophase while eclosion appears to anticipate thermophase onset. These findings suggest that eclosion and locomotor activity rhythms are controlled by different circadian oscillators. This fits with the ecological context of these vital life events. Timing of eclosion is critically important to wing development and the survival of the adult. This process is initiated after being underground, with minimal to no light input, for two weeks – therefore, the most reliable Zeitgeber would be daily soil temperature cycling. As these flies are diurnal, one could reasonably expect light to be the primary Zeitgeber for adult activity, as it is more consistent than temperature cycling. Overall, this implies that an organism’s life history and natural environment must be considered when investigating the circadian clock.

Circadian clocks are responsible for scheduling many behavioral and physiological processes to occur at the most appropriate time of day. The resulting daily rhythms also synchronize (entrain) to external environmental cues, known as zeitgebers. This phenomenon of entrainment enables organisms to anticipate daily changes in environmental conditions such as sunrise/sunset, temperature variations, availability of prey, etc. Given the critical nature of entrainment to survival, it is no surprise that the mechanism is conserved across taxa. The misalignment of the intrinsic clock with the external environment results in a plethora of negative consequences, made apparent by studies involving shift work and jet lag. The focus of the present study is to investigate the chronobiology of Larinioides cornutus (Araneidae), a nocturnal orb-weaving spider, with an emphasis on its entrainment to light:dark cycles. Because spiders have received scarce attention with respect to their chronobiology, it is instructive to compare the properties of spider circadian systems with those of the more established circadian model systems, such as Drosophilaand Murines. We found that both lights-off and lights-on are equally influential zeitgeber cues for (determines the phasing of) both activity onset and offset. Locomotor activity typically begins within a half hour after nightfall, continues throughout the night, and ceases just prior to dawn. Phase shifting experiments show that these spiders can re-entrain within 2 days to a light/dark cycle shifted by 6 hours, and within 3 days when shifted by 12 hours. These rates of re-entrainment occur at an extremely accelerated rate compared to mammals, which readjust to a time shift at a rate of around 1 day/ 1 hour of phase shift. In other words, spiders have a minimal jet-lag response. This suggests an increased level of plasticity in the spider circadian clock that has yet to be observed in other organisms. Typical of circadian rhythms in nearly all organisms, activity also persisted (free-runs) under constant conditions. However, in constant darkness (DD), a drastic change in periodicity was revealed in 66% of individuals, from 23.4 to 25.2. This particular phenomenon is rare and likely indicates the possible interaction of multiple oscillators. Further evidence to support this interpretation is the consistent periods of the rhythm displayed before and after the change. In contrast, under constant light (LL) conditions, 65% of spiders were arrhythmic, with 4 individuals ceasing activity completely. Significant periods detected in LL were normally distributed over an unusually broad range, from 16.7 to 34.9 hours, suggesting a high sensitivity to light. Because of the unusual rates of re-entrainment to light/dark cycles, the spontaneous changes in free-running period under DD, and arrhythmicity in LL, we propose that spiders are valuable comparative model organism for elucidating fundamental mechanisms of circadian clocks.

The change of day and night is one of the challenges all organisms are exposed to, as they have to adjust their physiology and behavior in an appropriate way. Therefore so called circadian clocks have evolved, which allow the organism to predict these cyclic changes of day and night. The underlying molecular mechanism is oscillating with its endogenous period of approximately 24 hours in constant conditions, but as soon as external stimuli, so called Zeitgebers, are present, the clocks adjust their period to exactly 24h, which is called entrainment. Studies in several species, including humans, animals and plants, showed that light is the most important Zeitgeber synchronizing physiology and behavior to the changes of day and night. Nevertheless also other stimuli, like changes in temperature, humidity or social interactions, are powerful Zeitgebers for entraining the clock. This thesis will focus on the question, how light influences the locomotor behavior of the fly in general, including a particular interest on the entrainment of the circadian clock. As a model organism Drosophila melanogaster was used. During the last years several research groups investigated the effect of light on the circadian clock and their results showed that several light input pathways to the clock contribute to wild-type behavior. Most of the studies focused on the photopigment Cryptochrome (CRY) which is expressed in about half of the 150 clock neurons in the fly. CRY is activated by light, degrades the clock protein Timeless (TIM) and hence entrains the clock to the light-dark (LD)-cycle resulting from changes of day and night. However, also flies lacking CRY are still able to entrain their clock mechanism as well as their activity-rest-rhythm to LD-cycles, clearly showing that the visual system of the fly also contributes to clock synchronization. The mechanism how light information from the visual system is transferred to the clock is so far still unknown. This is also true for so-called masking-effects which are changes in the behavior of the animal that are directly initiated by external stimuli and therefore independent of the circadian clock. These effects complement the behavior of the animals as they enable the fly to react quickly to changes in the environment even during the clock-controlled rest state. Both of these behavioral features were analyzed in more detail in this study. On the one hand, we investigated the influence of the compound eyes on the entrainment of the clock neurons and on the other hand, we tried to separate clock-controlled behavior from masking. To do so "nature-like" light conditions were simulated allowing the investigation of masking and entrainment within one experiment. The simulation of moonlight and twilight conditions caused significant changes in the locomotor behavior. Moonlit nights increased nocturnal activity levels and shifted the morning (M) and evening (E) activity bouts into the night. The opposite was true for the investigation of twilight, as the activity bouts were shifted into the day. The simulation of twilight and moonlight within the same experiment further showed that twilight appears to dominate over moonlight, which is in accordance to the assumption that twilight in nature is one of the key signals to synchronize the clock as the light intensity during early dawn rises similarly in every season. By investigating different mutants with impaired visual system we showed that the compound eyes are essential for the observed behavioral adaptations. The inner receptor cells (R7 and R8) are important for synchronizing the endogenous clock mechanism to the changes of day and night. In terms of masking, a complex interaction of all receptor cells seems to adjust the behavioral pattern, as only flies lacking photopigments in inner and outer receptor cells lacked all masking effects. However, not only the compound eyes seem to contribute to rhythmic activity in moonlit nights. CRY-mutant flies shift their E activity bout even more into the night than wild-type flies do. By applying Drosophila genetics we were able to narrow down this effect to only four CRY expressing clock neurons per hemisphere. This implies that the compound eyes and CRY in the clock neurons have antagonistic effects on the timing of the E activity bout. CRY advances activity into the day, whereas the compound eyes delay it. Therefore, wild-type behavior combines both effects and the two light inputs might enable the fly to time its activity to the appropriate time of day. But CRY expression is not restricted to the clock neurons as a previous study showed a rather broad distribution within the compound eyes. In order to investigate its function in the eyes we collaborated with Prof. Rodolfo Costa (University of Padova). In our first study we were able to show that CRY interacts with the phototransduction cascade and thereby influences visual behavior like phototaxis and optomotor response. Our second study showed that CRY in the eyes affects locomotor activity rhythms. It appears to contribute to light sensation without being a photopigment per se. Our results rather indicate that CRY keeps the components of the phototransduction cascade close to the cytoskeleton, as we identified a CRY-Actin interaction in vitro. It might therefore facilitate the transformation of light energy into electric signals. In a further collaboration with Prof. Orie Shafer (University of Michigan) we were able to shed light on the significance of the extraretinal Hofbauer-Buchner eyelet for clock synchronization. Excitation of the eyelet leads to Ca2+ and cAMP increases in specific clock neurons, consequently resulting in a shift of the flies´ rhythmic activity. Taken together, the experiments conducted in this thesis revealed new functions of different eye structures and CRY for fly behavior. We were furthermore able to show that masking complements the rhythmic behavior of the fly, which might help to adapt to natural conditions. / Der Wechsel von Tag und Nacht stellt für viele Organismen eine große Herausforderung dar, da sie ihre Physiologie und auch das Verhalten den äußeren Gegebenheiten anpassen müssen. Um dieser Aufgabe gerecht zu werden, haben viele Organismen innere Uhren entwickelt, welche es ihnen erlauben, den Wechsel von Tag und Nacht vorherzusehen. Diesen inneren Uhren liegt ein molekularer Mechanismus zugrunde, welcher einen Rhythmus von etwa 24 Stunden generiert. Eine wichtige Eigenschaft dieser Uhren ist es, dass sie durch äußere Faktoren, so genannte Zeitgeber, an den Tag-Nacht-Wechsel angepasst werden können. Viele Studien an Mensch, Tier und Pflanze weisen darauf hin, dass Licht der wichtigste Zeitgeber ist, wobei auch Temperatur, Luftfeuchtigkeit oder soziale Interaktionen die innere Uhr an den Tag-Nacht-Wechsel anpassen können. Ziel dieser Arbeit ist es, die Auswirkung von Licht auf das Lauf-verhalten und die innere Uhr genauer zu beleuchten, wozu der Modellorganismus Drosophila melanogaster herangezogen wird. Zahlreiche Forschergruppen haben sich bereits mit der Synchronisation der inneren Uhr durch Licht beschäftigt, wobei klar hervorgeht, dass die Taufliege verschiedene Möglichkeiten hat, Lichtinformationen für die Synchronisation der Uhr zu verwenden. Der wohl am besten untersuchte Prozess ist die Synchronisation durch das Pigment Cryptochrom. Dieses Molekül ist in etwa der Hälfte der Uhrneuronen exprimiert und greift direkt in den molekularen Uhrmechanismus ein, wodurch dieser an den Tag-Nacht-Wechsel angepasst werden kann. Schaltet man jedoch das Gen für dieses Molekül aus so zeigt sich, dass die Tiere dennoch dazu in der Lage sind sich an den Licht-Dunkel-Wechsel anzupassen. Dies bedeutet, dass die visuellen Organe Informationen an die innere Uhr weiterleiten können, wobei der Mechanismus dafür noch nicht vollständig entschlüsselt werden konnte. Selbiges trifft auf sogenannte Maskierungseffekte zu: Maskierung beschreibt eine Veränderung des Verhaltensmusters, welches nicht durch die innere Uhr gesteuert, sondern direkt durch äußere Reize hervorgerufen wird. Diese direkten Effekte komplettieren das Verhalten der Tiere, da sie dadurch selbst zu endogen ungünstigen Zeiten adäquat auf äußere Reize reagieren können. In dieser Arbeit wird sich beider Phänomene angenommen: Zum einen soll die Bedeutung des visuellen Systems für die Synchronisation der inneren Uhr genauer untersucht, und zum anderen soll uhrgesteuertes Verhalten von Maskierung getrennt werden. Zu diesem Zweck wurden Lichtbedingungen simuliert, die den natürlichen ähnelten und die Untersuchung beider lichtabhängiger Effekte ermöglichten. Die Untersuchung von Dämmerung und Mondlicht zeigte deutlich, dass diese starke Veränderungen im Lauf-Verhalten hervorrufen. Die Simulation von Mondlicht bewirkte einen Anstieg der Nachtaktivität und ein Verschieben der Aktivitätsmaxima der Fliege in die Nacht. Das Gegenteil war bei Dämmerungssimulation zu beobachten, da die Tiere mehr Aktivität in den Tag legten. Bei gleichzeitiger Simulation von Mondlicht und Dämmerungsphasen zeigte sich, dass die Dämmerung ein stärkerer Zeitgeber ist als Mondlicht ist. Dieses Ergebnis geht einher mit der Annahme, dass die Dämmerung ein wichtiges Signal für die Synchronisation der inneren Uhr ist, da der Anstieg der Lichtintensität am frühen Morgen unabhängig von der Jahreszeit sehr ähnlich ist. Die Untersuchung von verschiedensten Mutanten konnte zudem zeigen, dass die Komplexaugen der Fliege von größter Bedeutung für die beobachteten Veränderungen im Verhaltensmuster und die Anpassung der inneren Uhr an "natürliche" Lichtbedingungen sind. Dabei stellte sich heraus, dass vor allem die inneren Rezeptorzellen wichtig für die Synchronisation der inneren Uhr und somit uhrgesteuerter Verhaltensänderungen sind. Für Maskierungseffekte scheint eine komplexe Interaktion von mehreren Rezeptorzellen für die Anpassung an Dämmerungs- und Mondlichtbedingungen vorzuliegen, da diese nur bei Mehrfachmutationen verschiedener Rhodopsine, den lichtabsorbierenden Molekülen der Fliege, verschwanden. Jedoch scheinen nicht nur die Komplexaugen das rhythmische Verhalten in Mondlichtnächten zu beeinflussen. Wird das Gen für Cryptochrom, dem Photorezeptor der inneren Uhr, ausgeschaltet, verschieben die Tiere ihre Abendaktivität noch stärker in die Nacht als es bereits beim Wildtyp der Fall ist. Durch verschiedene genetische Manipulationen konnten wir den Grund dieses Verhaltens auf die Expression von Cryptochrom in nur vier Uhrneuronen pro Hemisphäre zurückverfolgen. Zugleich zeigten unsere Ergebnisse, dass die Komplexaugen und Cryptochrom entgegengesetzte Wirkung auf das Timing der Abendaktivität haben. Während die Komplexaugen die Abendaktivität in die Nacht hinein schieben, bewirkt Cryptochrom, dass die Aktivität noch während des Tages stattfindet. Dies bedeutet, dass das wildtypische Verhalten eine Mischung aus beiden Lichteingängen ist und sich die Tiere somit ideal an die äußeren Gegebenheiten anpassen können. Cryptochrom wird jedoch nicht nur in den Uhrneuronen, sondern unter anderem auch in den Komplexaugen der Tiere exprimiert. Um die Funktion in den Augen genauer zu untersuchen, konnten wir in Kollaboration mit Prof. Rodolfo Costa (University of Padova) zunächst zeigen, dass CRY mit der Phototransduktionskaskade über das Protein INAD interagiert und dadurch visuelles Verhalten, wie zum Beispiel Phototaxis oder die optomotorische Antwort, beeinflussen kann. In weiteren Experimenten konnten wir zudem zeigen, dass CRY in den Augen die lokomotorische Aktivität der Fliegen beeinflusst. Dabei trägt es zur Wahrnehmung von Licht bei, ohne jedoch per se ein Photopigment zu sein. Vielmehr scheint CRY die Phototransduktion dahingehend zu verändern, dass es den Phototransduktionskomplex an das Cytoskelett innerhalb der Rhabdomere bindet und somit die Umwandlung von Lichtenergie in elektrische Signale erleichtert. Zusammen mit Prof. Orie Shafer (University of Michigan) ist es uns zudem gelungen, die Rolle des extraretinalen Hofbauer-Buchner-Äugleins für die Synchronisation der Uhr genauer zu beleuchten. Die Anregung des Äugleins führte dabei zu einem Anstieg der Ca2+ und cAMP Mengen in bestimmten Uhrneuronen und dies bewirkte eine Phasenverschiebung des Verhaltens der Taufliege. Somit konnten in dieser Arbeit neue Erkenntnisse über die Funktionen von Cryptochrom und verschiedener Augenstrukturen für das Verhalten der Fliege gewonnen werden. Dabei konnten die Bedeutungen der inneren Uhr sowie von Maskierungseffekten für das Verhalten der Tiere in der Natur herausgearbeitet werden.

The rotation of the earth around its axis causes recurring and predictable changes in the environment. To anticipate those changes and adapt their physiology and behavior accordingly, most organisms possess an endogenous clock. The presence of such a clock has been demonstrated for several ant species including Camponotus ants, but its involvement in the scheduling of daily activities within and outside the ant nest is fairly unknown. Timing of individual behaviors and synchronization among individuals is needed to generate a coordinated collective response and to maintain colony function. The aim of this thesis was to investigate the presence of a circadian clock in different worker castes, and to determine the daily timing of their behavioral tasks within the colonies of two nectar-collecting Camponotus species. In chapter I, I describe the general temporal organization of work throughout the worker life in the species Camponotus rufipes. Continuous tracking of behavioral activity of individually- marked workers for up to 11 weeks in subcolonies revealed an age-dependent division of labor between interior and exterior workers. After eclosion, the fairly immobile young ants were frequently nurtured by older nurses, yet they started nursing the brood themselves within the first 48 hours of their life. Only 60% of workers switched to foraging at an age range of one to two weeks, likely because of the reduced needs within the small scale of the subcolonies. Not only the transition rates varied between subcolonies, but also the time courses of the task sequences between workers did, emphasizing the timed allocation of workers to different tasks in response to colony needs. Most of the observed foragers were present outside the nest only during the night, indicating a distinct timing of this behavioral activity on a daily level as well. As food availability, humidity and temperature levels were kept constant throughout the day, the preference for nocturnal activity seems to be endogenous and characteristic for C. rufipes. The subsequent monitoring of locomotor activity of workers taken from the subcolonies revealed the presence of a functional endogenous clock already in one-day old ants. As some nurses displayed activity rhythms in phase with the foraging rhythm, a synchronization of these in-nest workers by social interactions with exterior workers can be hypothesized. Do both castes use their endogenous clock to schedule their daily activities within the colony? In chapter II, I analyzed behavioral activity of C. rufipes foragers and nurses within the social context continuously for 24 hours. As time-restricted access to food sources may be one factor affecting daily activities of ants under natural conditions, I confronted subcolonies with either daily pulses of food availability or ad libitum feeding. Under nighttime and ad libitum feeding, behavioral activity of foragers outside the nest was predominantly nocturnal, confirming the results from the simple counting of exterior workers done in chapter I. Foragers switched to diurnality during daytime feeding, demonstrating the flexible and adaptive timing of a daily behavior. Because they synchronized their activity with the short times of food availability, these workers showed high levels of inactivity. Nurses, in contrast, were active all around the clock independent of the feeding regime, spending their active time largely with feeding and licking the brood. After the feeding pulses, however, a short bout of activity was observed in nurses. During this time period, both castes increasingly interacted via trophallaxis within the nest. With this form of social zeitgeber, exterior workers were able to entrain in-nest workers, a phenomenon observed already in chapter I. Under the subsequent monitoring of locomotor activity under LD conditions the rhythmic workers of both castes were uniformly nocturnal independent of the feeding regime. This endogenous activity pattern displayed by both worker castes in isolation was modified in the social context in adaption to task demands. Chapter III focuses on the potential factors causing the observed plasticity of daily rhythms in the social context in the ant C. rufipes. As presence of brood and conspecifics are likely indicators of the social context, I tested the effect of these factors on the endogenous rhythms of otherwise isolated individuals. Even in foragers, the contact to brood triggered an arrhythmic activity pattern resembling the arrhythmic behavioral activity pattern seen in nurses within the social context. As indicated in chapter I and II, social interaction could be one crucial factor for the synchronization of in nest activities. When separate groups were entrained to phase-shifted light-dark-cycles and monitored afterwards under constant conditions in pairwise contact through a mesh partitioning, both individuals shifted parts of their activity towards the activity period of the conspecific. Both social cues modulated the endogenous rhythms of workers and contribute to the context dependent plasticity in ant colonies. Although most nursing activities are executed arrhythmically throughout the day (chapter II), previous studies reported rhythmic translocation events of the brood in Camponotus nurses. As this behavior favors brood development, the timing of the translocations within the dark nest seems to be crucial. In chapter IV, I tracked translocation activity of all nurses within subcolonies of C. mus. Under the confirmed synchronized conditions of a LD-cycle, the daily pattern of brood relocation was based on the rhythmic, alternating activity of subpopulations with preferred translocation direction either to the warm or to the cold part of the temperature gradient at certain times of the day. Although the social interaction after pulse feeding had noticeable effects on the in-nest activity in C. rufipes (chapter I and II), it was not sufficient to synchronize the brood translocation rhythm of C. mus under constant darkness (e.g. when other zeitgebers were absent). The free-running translocation activity in some nurses demonstrated nevertheless the involvement of an endogenous clock in this behavior, which could be entrained under natural conditions by other potential non-photic zeitgebers like temperature and humidity cycles. Daily cycling of temperature and humidity could not only be relevant for in-nest activities, but also for the foraging activity outside the nest. Chapter V focuses on the monitoring of field foraging rhythms in the sympatric species C. mus and C. rufipes in relation to abiotic factors. Although both species had comparable critical thermal limits in the laboratory, foragers in C. mus were strictly diurnal and therefore foraged under higher temperatures than the predominant nocturnal foragers in C. rufipes. Marking experiments in C. rufipes colonies with higher levels of diurnal activity revealed the presence of temporally specialized forager subpopulations. These results suggest the presence of temporal niches not only between the two Camponotus species, but as well between workers within colonies of the same species. In conclusion, the temporal organization in colonies of Camponotus ants involves not only the scheduling of tasks performed throughout the worker life, but also the precise timing of daily activities. The necessary endogenous clock is already functioning in all workers after eclosion. Whereas the light-dark cycle and food availability seem to be the prominent zeitgebers for foragers, nurses may rely more on non-photic zeitgeber like social interaction, temperature and humidity cycles. / Die Drehung der Erde um ihre eigene Achse erzeugt wiederkehrende und vorhersehbare Umweltschwankungen. Um diese Schwankungen zu antizipieren und Physiologie sowie Verhalten entsprechend anzupassen, besitzen fast alle Organismen eine innere Uhr. Bei einigen Ameisenarten, Camponotus Ameisen eingenommen, wurde die Präsenz einer inneren Uhr bereits bestätigt. Wie diese Uhr allerdings zur zeitlichen Abstimmung der Tagesaktivitäten innerhalb und außerhalb des Ameisennestes genutzt wird, war bis jetzt weitestgehend unbekannt. Für die Koordination einer kollektiven Verhaltensantwort und die Aufrechterhaltung der Kolonie ist dabei nicht nur die zeitliche Steuerung vom Verhalten Einzelner notwendig, sondern auch eine Synchronisation zwischen den Arbeiterinnen. Das Ziel dieser Doktorarbeit war es, die mögliche Präsenz einer inneren Uhr in verschiedenen Arbeiterkasten zu untersuchen, und die zeitliche Koordination von Tagesaktivitäten dieser Kasten innerhalb der Kolonien zweier Camponotus Ameisenarten zu bestimmen. In Kapitel I beschreibe ich die grundlegende zeitliche Organisation der Arbeitsteilung im Laufe des Arbeiterinnenlebens in der Art Camponotus rufipes. Mithilfe einer lückenlosen Verfolgung der Tagesaktivitäten von individuell markierten Tieren in Subkolonien über bis zu 11 Wochen konnte eine altersabhängige Arbeitsteilung zwischen Innen- und Außendienstarbeiterinnen nachgewiesen werden. Nach dem Schlüpfen wurden die eher unbeweglichen jungen Ameisen oft durch ältere Brutpflegerinnen versorgt, engagierten sich dann aber schon innerhalb der ersten 48 Stunden ihres Lebens selbst in der Brutpflege. Wahrscheinlich wegen der verminderten Notwendigkeit zur ausgedehnten Futtersuche innerhalb der kleinen Versuchskolonien wechselten nur 60% der Innendienstarbeiterinnen nach ein bis zwei Wochen zum Fouragieren außerhalb der Kolonie. Nicht nur variierte der Prozentsatz des Verhaltensübergangs von Brutpflegerin zur Sammlerin zwischen den Subkolonien, sondern auch innerhalb der Subkolonien unterschieden sich Arbeiterinnen im Zeitverlauf der Aufgabenfolge. Diese Ergebnisse betonen die gezielte, zeitliche Zuweisung von Arbeiterinnen zu einer bestimmten Arbeiterkaste je nach Bedarf der Kolonie. In diesem Experiment waren die Sammlerinnen vorwiegend nur während der Nachtphase außerhalb der Kolonie aktiv, was wiederum eine genaue zeitliche Koordination des Sammelverhaltens auf Tagesbasis zeigt. Da die Futterverfügbarkeit sowie Temperatur- und Luftfeuchte über den Tag hinweg konstant gehalten wurden, scheint die bevorzugte Nachtaktivität endogen und charakteristisch für C. rufipes zu sein. Durch das anschließende Monitoring der Lokomotoraktivität von Arbeiterinnen aus diesen Subkolonien konnte gezeigt werden, dass schon einen Tag alte Ameisen eine funktionierende innere Uhr besitzen. Der Aktivitätsrhythmus mancher Brutpflegerinnen war dabei in Phase mit dem Sammelrhythmus der Kolonie, weswegen man von einer Synchronisation dieser Inndienstarbeiterinnen durch soziale Interaktion mit Außendienstarbeiterinnen ausgehen kann. Doch nutzen beide Kasten ihre innere Uhr auch, um ihre Tagesaktivitäten innerhalb der Kolonie zeitlich abzustimmen? In Kapitel II habe ich die Verhaltensaktivität von C. rufipes Futtersammlerinnen und Brutpflegerinnen in ihrem sozialen Umfeld kontinuierlich für 24 Stunden verfolgt. Da der beschränkte Zugriff zu Futterquellen einer der Faktoren sein könnte, der die Tagesaktivitäten von Ameisen in der Natur beeinflusst, wurden Subkolonien entweder nur pulsartig oder ad libitum gefüttert. Während der Nacht- und ad libitum Fütterung waren Sammlerinnen vorwiegend nachtaktiv, was die Ergebnisse der simplen Zählung von Außendiensttieren in Kapitel I bestätigt. Während der Tagesfütterung wurden die Sammlerinnen tagaktiv, was die flexible und adaptive zeitliche Anpassung dieses täglichen Verhaltens veranschaulicht. Unabhängig von der Fütterungszeit waren Brutpflegerinnen rund um die Uhr aktiv, wobei sie die größte Zeit mit Fütterung und Säuberung der Brut verbrachten. Jedoch konnte kurz nach den Fütterungspulsen ein kurzer Aktivitätsanstieg verzeichnet werden, welcher auf die erhöhte Interaktion durch Trophallaxis mit den Sammlerinnen zurückzuführen ist. Wie bereits schon in Kapitel I angedeutet, können Außendiensttiere mithilfe dieses sozialen Zeitgebers Arbeiterinnen im Nest synchronisieren. Im anschließenden Monitoring der Lokomotoraktivität unter Licht-Dunkel-Bedingungen waren alle rhythmischen Arbeiterinnen einheitlich nachtaktiv, unabhängig von der vorausgegangen Fütterungszeit. Damit werden die endogenen Aktivitätsmuster, die beide Kasten in Isolation zeigen, im sozialen Kontext in Anpassung an die speziellen Anforderungen an die Kasten modifiziert. Schwerpunkt des Kapitels III ist die Untersuchung der potentiellen Faktoren, die die gezeigte Plastizität der Tagesrhythmen bei Ameisen der Art C. rufipes bedingen. Da unter anderem das Vorhandensein von Brut und Artgenossinnen sozialen Kontext signalisieren können, wurde der Effekt dieser Faktoren auf die endogenen Rhythmen von ansonsten isolierten Individuen untersucht. Selbst in Sammlerinnen verursachte der Kontakt zu Brut ein arrhythmisches Aktivitätsmuster, welches dem Verhaltensmuster von Brutpflegerinnen innerhalb der Kolonie gleicht. Wie schon in Kapitel I und II deutlich wurde, könnten soziale Interaktionen einen wesentlichen Beitrag zur Synchronisation der Nestaktivitäten leisten. Dazu wurden Gruppen getrennt voneinander mit phasenverschobenen Licht-Dunkel-Zyklen entraint, und Tiere anschließend in paarweisem Kontakt durch ein Netzgitter aufgezeichnet. Beide Individuen verschoben einen Teil ihrer Aktivität in die Aktivitätsperiode des Partners. Damit modulierten beide getesteten sozialen Faktoren die endogenen Rhythmen der Arbeiterinnen, was letztendlich zur kontextabhängigen Plastizität der Rhythmen in Ameisenkolonien beiträgt. Obwohl Brutpflegerinnen die meisten Verhaltensweisen arrhythmisch während des ganzen Tages ausüben (Kapitel II), zeigten vorangegangene Studien rhythmische Brutverlagerungen bei Brutpflegerinnen der Camponotus-Arten. Da dieses Verhalten die Brutentwicklung fördert, scheint das Timing der Verlagerungen innerhalb des ansonsten dunklen Nestes essentiell zu sein. In Kapitel IV verfolgte ich die Verlagerungsaktivität von allen Brutpflegerinnen in Subkolonien der Art C. mus. Unter den gesichert synchronisierten Bedingungen eines LD-Zykluses basierte das Brutverlagerungsmuster auf der rhythmischen, abwechselnden Aktivität von zwei Subpopulationen mit bevorzugter Verlagerungsrichtung in entweder den warmen oder kalten Bereich des Temperaturgradienten zu bestimmten Tageszeiten. Obwohl die soziale Interaktion nach Pulsfütterung einen deutlichen Einfluss auf die Nestaktivität bei C. rufipes hatte (Kapitel I und II), reichte diese Interaktion nicht aus um den Brutverlagerungsrhythmus bei C. mus innerhalb des dunklen Nests (d.h. unter Abwesenheit sonstiger Zeitgeber) zu synchronisieren. Nichtsdestotrotz zeigte der Freilauf der Brutverlagerungsrhythmen in einigen Brutpflegerinnen die Beteiligung einer inneren Uhr, welche durch anderweitige nicht-photische Zeitgeber wie Temperatur- und Feuchtigkeitszyklen synchronisiert werden könnte. Tageszyklen in Temperatur und Feuchtigkeit könnten nicht nur relevant sein für Aktivitäten innerhalb des Nests, sondern auch für die Fouragieraktivität außerhalb des Nests. In Kapitel V wurden Fouragierrhythmen im Freiland bei den sympatrisch vorkommenden Ameisenarten C. mus und C. rufipes in Abhängigkeit von abiotischen Faktoren betrachtet. Obwohl die beiden Arten unter Laborbedingungen ähnliche kritische Temperaturgrenzen aufzeigten, waren die Fourageure der Art C. mus strikt tagaktiv und sammelten deswegen unter höheren Temperaturen Futter als die vorwiegend nachtaktiven Fourageure der Art C. rufipes. Bei C. rufipes Kolonien mit erhöhter Tagaktivität wiesen Markierexperimente das Vorkommen von zeitlich spezialisierten Fourageur-Subpopulationen nach. Damit deuten die Ergebnisse nicht nur das Vorkommen von unterschiedlichen zeitlichen Nischen innerhalb der beiden Camponotus-Arten an, sondern auch zwischen Arbeiterinnen von Kolonien derselben Art. Zusammenfassend gesehen umspannt die zeitliche Organisation in Kolonien der Camponotus-Ameisen nicht nur die zeitliche Planung der Aufgaben, die über das Arbeiterinnenleben hinweg ausgeführt werden, sondern auch das genaue Terminierung von Tagesaktivitäten. Bereits nach dem Schlüpfen besitzen allen Arbeiterinnen eine funktionsfähige und für die zeitliche Organisation notwendige innere Uhr. Während der Licht-Dunkel-Zyklus und Futterverfügbarkeit die bedeutenden Zeitgeber für Fourageure zu sein scheinen, könnten Brutpflegerinnen eher auf nicht-photische Zeitgeber wie soziale Interaktion, Temperatur- und Feuchtigkeitszyklen angewiesen sein.

Le Brain-derived Neurotrophic Factor (BDNF) est impliqué dans les processus cognitifs impliquant l'hippocampe et les structures corticales. Cette étude avait pour but d’analyser les effets postopératoires sur l’expression du BDNF dans ces structures cérébrales.Ainsi, les effets d’une anesthésie de courte durée au propofol, d’une chirurgie mineure et du lipopolysaccharide (LPS) sur l'altération de l’expression du BDNF ont été analysée dans l'hippocampe et le cortex de deux modèles de rongeurs nocturnes et diurnes, correspondant respectivement des jeunes rats Sprague Dawley mâles et des Arvicanthis ansorgei.Dans un premier temps, la rythmicité nycthémérale de l’expression du BDNF a été analysée.Les quantités de BDNF présentes dans le cortex et l'hippocampe ont été déterminées par une technique ELISA. Il s’est avéré que, dans l'hippocampe et le cortex de rat et d’A. ansorgei, le BDNF suit une rythmicité sur 24 heures. La quantité de BDNF atteint un maximum à ZT5(i.e., 5 heures après le début de l’exposition à la lumière). Dans un deuxième temps, les effets sur l’expression du BDNF ont été analysés après administration de propofol et/ou LPS, ainsi que lors d’une chirurgie légère. Parallèlement,l’impact de ces traitements sur la mémoire a été testé à l’aide d’un test d'évitement passif.Nos résultats indiquent que la quantité de BDNF est régulée positivement dans l'hippocampe et le cortex de rats lorsque les animaux ont subit une anesthésie de courte durée au propofol en présence ou absence de LPS. A l’opposé, une chirurgie mineure (sous anesthésie propofol)n’a aucun effet sur les quantités de BDNF.En conclusion, ces études mettent en évidence des effets majeurs d’une anesthésie sur l’expression du BDNF, ainsi que les effets protecteurs du propofol sur la neuroinflammation induite par le LPS. / Brain-derived neurotrophic factor (BDNF) is involved in cognition and hippocampus and cortical structures are important in cognition. The present study was designed to analyse the post-operative effects on BDNF. For this purpose, we examined the effects of short duration propofol anaesthesia, LPS and minor surgery on the BDNF protein alteration in the hippocampus and cortex.Young male Sprague Dawley rats were used in all experiments except Arvicanthis ansorgei which were used to study the circadian rhythmicity of BDNF protein as model for diurnal rodents. The quantity of BDNF protein present in the cortex and hippocampal supernatants was determined with an ELISA technique. Memory was tested by fear conditioning using the classic fear conditioning preparation (passive avoidance apparatus).The major finding on BDNF protein in control conditions is that the BDNF protein followed a circadian rhythmicity during the 24 hours of day in the rat’s hippocampus and cortex. The concentration of BDNF protein has been observed to reach a maximum at ZT5 (5 hours afterthe light on period) whether the animals were nocturnal or diurnal. In addition, we found that BDNF protein amount is up regulated in the hippocampus and cortex of rats when they were submitted to short duration propofol anaesthesia, as well as LPS and no effect when minor surgery under propofol anaesthesia was performed.In conclusion, these studies illustrate the dramatic effects of post-operative conditions and neuroinflammation induced by LPS on cognition and the potential mechanism involved. This study also suggests the protective effects of the short duration propofol anaesthesia against neuroinflammation induced by LPS.

Introdução: Interações sociais podem afetar diretamente ritmos biológicos, independente de seu papel na organização do zeitgeber fótico. A força do zeitgeber social refere-se ao padrão rítmico das interações sociais e pode ser quantificada através da escala de ritmo social. Objetivos: Principais: 1. Adequar o instrumento de avaliação do ritmo social ao contexto de pesquisa. 2. Estudar o ritmo social em humanos. Secundários: 1. Estabecer uma versão abreviada da Escala de Ritmo Social com vistas à aplicação em pesquisa. 2. Estabelecer uma versão da Escala de Ritmo Social de 17 itens para o português angolano, para estudos transculturais. 3. Investigar a correlação entre ritmo social, fase do sono e sintomas psiquiátricos menores em trabalhadores saudáveis. Métodos: Na primeira parte do trabalho a Escala de Ritmo Social (ERS-17) foi submetida a um processo de adequação a dois contextos de pesquisa diferentes. Na segunda parte, a escala foi utilizada em um estudo clínico para avaliar a correlação entre sintomatologia psiquiátrica menor e a variável ritmo social em uma amostra saudável. Tomando como padrão-ouro a ERS-17, foram comparados escores de regularidade e quantidade de atividades de 167 sujeitos saudáveis, 25 portadores de epilepsia mioclônica juvenil e 16 portadores de transtorno depressivo, para o estabelecimento da Versão Breve. No estudo transcultural, a versão brasileira da Escala de Ritmo Social foi submetida à avaliação de 10 estudantes universitários angolanos, que analisaram o grau de clareza de cada uma das 15 sentenças do instrumento por meio da Escala Analógico-Visual de 10 cm e propuseram modificações na escala. Foi realizada revisão dos resultados para a elaboração da versão final, bem como prova de leitura e relatório final. No estudo clínico, transversal, foram avaliados 143 trabalhadores saudáveis do HCPA. Sintomas psiquiátricos menores foram avaliados pelo Self-Repport Questionnaire (SRQ-20), e ritmo social foi avaliado pela ERS-17. Exposição à luz e variáveis do sono foram avaliadas pelo Munich Choronotype Questionnaire (MCTQ). Resultados: Foi estabelecida uma versão breve de 6 itens com boa concordância com relação ao padrão-ouro k=0,51; p<0,001 e significativa correlação entre ambas: (r=0,87; p<0,001). No estudo transcultural foi estabelecida uma versão angolana que manteve uma equivalência de itens com relação à versão em português brasileiro e grau satisfatório de clareza e equivalência semântica. No estudo clínico, Quantidade de atividades correlacionou com escolaridade e tempo médio do sono e, inversamente, com (Ponto Médio do Sono) MSF e SRQ-20. Regularidade correlacionou com idade, SRQ-20 e número de dias trabalhados. SRQ-20 correlacionou inversamente com regularidade e quantidade de atividades. Conclusões: No estabelecimento da versão breve, concluiu-se que a simplificação da escala diminui a porcentagem de itens não preenchidos, o custo em material impresso e facilita a padronização. O estudo transcultural demonstrou que apesar de ser o Português o idioma oficial nos dois países, há diferenças culturais significativas que podem influenciar os resultados caso sejam ignoradas. O estudo clínico demonstrou que variáveis de ritmo social tiveram correlação inversa com sintomas psiquiátricos menores, que foram mais explicados por baixos níveis de atividade do que por baixos níveis de regularidade. / Background: Social rhythms can directly affect biological rhythms, independent of its role in organizing the photic zeitgeber. The strength of the social zeitgeber refers to the rhythmic pattern of social interactions and can be measured by Social Rhythm Metric. Objectives: Main Objectives: 1. To match the assessment tool of social rhythm to the research context. 2. To Study the social rhythm in humans. Secondary Objectives: 1. Establish an abbreviated version of the Social Rhythm Metric-17 for use in research. 2. Establish a version of the SRM-17 for the Angolan Portuguese, for cross-cultural studies. 3. To investigate the correlation between social rhythm, sleep phase and minor psychiatric symptoms in healthy workers. Methods: In the first part of this work, the Social Rhythm Metric (SRM-17) was submitted to a process of adaptation to two different research contexts. In the second part, the scale was used in a clinical study to evaluate the correlation between minor psychiatric symptomatology and the variable social rhythm in a healthy sample. Taking as gold standard SRM-17, were compared scores of regularity and amount of activities of 167 healthy subjects, 25 patients with juvenile myoclonic epilepsy and 16 patients with major depressive disorder, for establishing the Brief Version. In the cross-cultural study, the Brazilian version of the of SRM-17 was submitted to evaluation of 10 college students Angolans, who analyzed the clarity of each of the 15 sentences of the instrument through the Visual Analog Scale-10 cm and proposed modifications. Review of the results was performed for the final version, as well as proof reading and final report. In the clinical study, cross-sectional, were evaluated 143 healthy workers from HCPA. Minor psychiatric symptoms were assessed by the Self-Repport Questionnaire (SRQ-20) and social rhythm was assessed by SRM-17. Light exposure and Sleep variables wereassessed by MCTQ. Results: Was established brief version of 6 items with good agreement with respect to the gold standard (k = 0.51, p <0.001) and significant correlation between the two: (r = 0.87, p <0.001). In the transcultural study was established an angolan version that kept an equivalence of items with respect to Brazilian Portuguese version of SRM-17 and satisfactory degree of clarity and semantic equivalence. In the clinical study, number of activities correlated with schooling and average sleep time and inversely, with Midpoint of sleep (MSF) and SRQ score. Regularity correlated with age, SRQ score and number of days worked. SRQ score correlated inversely with regularity and amount of activities. Conclusions: When establishing of the short version, it was concluded that the simplification of the scale decreases the percentage of unanswered questions, the print cost, and facilitates the standardization. The transcultural study showed that, in spite of the common language in both countries, there are significant cultural differences which can inffluence the results when ignored. The clinical study showed that social rhythm variables were inversely correlated with minor psychiatric symptoms, which were explained more by lower activity levels than low levels of regularity.

O trabalho é considerado um importante zeitgeber social. Objetivo: O objetivo do presente estudo é avaliar o ritmo social de pacientes adultos dependente de crack, internados na Unidade de Adição/ Unidade Álvaro Alvim do Hospital de Clínicas de Porto Alegre. Método: Participaram da pesquisa 50 pacientes dependentes de crack, internados para desintoxicação e reabilitação, aos quais foram aplicados questionários sócio-demográficos que permitiram conhecer a situação social, de moradia, renda, trabalho e emprego, tratamentos prévios e rede sócio-assistencial dos participantes, questionário para avaliação de indivíduos matutinos e vespertinos, escala breve de avaliação de ritmo social e revisão de prontuário. Resultados: A média de idade da amostra foi de 34,6 anos, 54% solteiros, com maior predominância na religião católica (54,3%). Cerca de 40% dos indivíduos contam com renda familiar mensal de 3 salários mínimos ou mais. Dos indivíduos que estão trabalhando ou em benefício do INSS (60%), 14% desenvolve as suas atividades no comércio, e cerca de 12 % trabalham na construção civil. A média da regularidade das atividades desenvolvidas (HITs) ficou em torno de 5,8 e a média do montante de atividades desenvolvidas (ALIs) foi de 33,8. Não Houve diferença significativa na correlação entre abandono de tratamento. Com relação à ritimicidade (5,8), os pacientes internados apresentaram um alto índice de regularidade, comparados com pessoas sem uso de drogas não internadas (4,2).1. Não foi encontrada relação entre o cronotipo dos participantes e o resultado dos HITs e ALIs. Conclusão: Apesar de ser mencionado o trabalho como um dos principais motivos para abandono de tratamento, os resultados deste trabalho não sustentam esta premissa. A situação de trabalho e a profissão não estão associadas ao abandono prévio de tratamento. Por outro lado, contrariando nossa hipótese inicial, a escolaridade aparece de maneira significativa, sendo evidenciado que quanto maior a escolaridade maior o índice de abandono precoce. A relação entre HITs e ALIs sugere que quanto mais atividades desenvolvidas, maior a regularidade com que elas foram realizadas durante a internação. No entanto, estudos futuros de segmento serão necessários para avaliar a manutenção desta regularidade. / Work is considered an important social zeitgeber. Objective: The aim of this study is describe the social rhythm of adult crack-cocaine users that are hospitalized in the Addiction Treatment Unite of the Hospital of Clinics of Porto Alegre. Method: 50 crack-cocaine users were interviewed after admission for detoxification and rehabilitation. We performed interviews with socio-demographic questionnaires that allowed us to access the social characteristics, housing, income, labor and employment, previous treatments and social assistance network. Also, they answer to a instrument to identify which individuals were morning or evening subjects, the Brief Social Rhythm Scale and chart review were assessed. Results: Mean age of the sample was 34.6 years old, and 54% of individuals reported to be single with predominance in the Catholic religion (54.3%). About 40% of the sample have a monthly family income of three minimum wages or more. Among individuals who are currently working or receive a benefit from Government (60%), 14% develop their activities in trade and 12% work in construction. The average of regularity of activities performed inside the inpatient unit (HITs) was around 5.8 and the average of amount of activities performed inside the inpatient unit (ALIs) was 33.8. There was no significant difference in the correlation between treatment dropout and rhythmicity. Regarding rhythmicity (5.8), hospitalized patients reported high levels of regularity when compared to individuals who were not hospitalized, neither had drug use (4.2) .1 We did not find a correlation between participant’s chronotipes and HITs and ALIs results. Conclusion: Despite work is cited as a major reason for treatment dropout, the results of this study do not support this premise. Work situation and the profession are not associated with prior treatment dropout. Contrary to our initial hypothesis, schooling appears as an important issue because it is significantly associated to early treatment dropout. The relationship between HITs and ALIs suggests that the more activities were developed, the greater the regularity with which they were performed during hospitalization. However, future follow-up studies are needed to evaluate the maintenance of this regularity.

Introdução: Interações sociais podem afetar diretamente ritmos biológicos, independente de seu papel na organização do zeitgeber fótico. A força do zeitgeber social refere-se ao padrão rítmico das interações sociais e pode ser quantificada através da escala de ritmo social. Objetivos: Principais: 1. Adequar o instrumento de avaliação do ritmo social ao contexto de pesquisa. 2. Estudar o ritmo social em humanos. Secundários: 1. Estabecer uma versão abreviada da Escala de Ritmo Social com vistas à aplicação em pesquisa. 2. Estabelecer uma versão da Escala de Ritmo Social de 17 itens para o português angolano, para estudos transculturais. 3. Investigar a correlação entre ritmo social, fase do sono e sintomas psiquiátricos menores em trabalhadores saudáveis. Métodos: Na primeira parte do trabalho a Escala de Ritmo Social (ERS-17) foi submetida a um processo de adequação a dois contextos de pesquisa diferentes. Na segunda parte, a escala foi utilizada em um estudo clínico para avaliar a correlação entre sintomatologia psiquiátrica menor e a variável ritmo social em uma amostra saudável. Tomando como padrão-ouro a ERS-17, foram comparados escores de regularidade e quantidade de atividades de 167 sujeitos saudáveis, 25 portadores de epilepsia mioclônica juvenil e 16 portadores de transtorno depressivo, para o estabelecimento da Versão Breve. No estudo transcultural, a versão brasileira da Escala de Ritmo Social foi submetida à avaliação de 10 estudantes universitários angolanos, que analisaram o grau de clareza de cada uma das 15 sentenças do instrumento por meio da Escala Analógico-Visual de 10 cm e propuseram modificações na escala. Foi realizada revisão dos resultados para a elaboração da versão final, bem como prova de leitura e relatório final. No estudo clínico, transversal, foram avaliados 143 trabalhadores saudáveis do HCPA. Sintomas psiquiátricos menores foram avaliados pelo Self-Repport Questionnaire (SRQ-20), e ritmo social foi avaliado pela ERS-17. Exposição à luz e variáveis do sono foram avaliadas pelo Munich Choronotype Questionnaire (MCTQ). Resultados: Foi estabelecida uma versão breve de 6 itens com boa concordância com relação ao padrão-ouro k=0,51; p<0,001 e significativa correlação entre ambas: (r=0,87; p<0,001). No estudo transcultural foi estabelecida uma versão angolana que manteve uma equivalência de itens com relação à versão em português brasileiro e grau satisfatório de clareza e equivalência semântica. No estudo clínico, Quantidade de atividades correlacionou com escolaridade e tempo médio do sono e, inversamente, com (Ponto Médio do Sono) MSF e SRQ-20. Regularidade correlacionou com idade, SRQ-20 e número de dias trabalhados. SRQ-20 correlacionou inversamente com regularidade e quantidade de atividades. Conclusões: No estabelecimento da versão breve, concluiu-se que a simplificação da escala diminui a porcentagem de itens não preenchidos, o custo em material impresso e facilita a padronização. O estudo transcultural demonstrou que apesar de ser o Português o idioma oficial nos dois países, há diferenças culturais significativas que podem influenciar os resultados caso sejam ignoradas. O estudo clínico demonstrou que variáveis de ritmo social tiveram correlação inversa com sintomas psiquiátricos menores, que foram mais explicados por baixos níveis de atividade do que por baixos níveis de regularidade. / Background: Social rhythms can directly affect biological rhythms, independent of its role in organizing the photic zeitgeber. The strength of the social zeitgeber refers to the rhythmic pattern of social interactions and can be measured by Social Rhythm Metric. Objectives: Main Objectives: 1. To match the assessment tool of social rhythm to the research context. 2. To Study the social rhythm in humans. Secondary Objectives: 1. Establish an abbreviated version of the Social Rhythm Metric-17 for use in research. 2. Establish a version of the SRM-17 for the Angolan Portuguese, for cross-cultural studies. 3. To investigate the correlation between social rhythm, sleep phase and minor psychiatric symptoms in healthy workers. Methods: In the first part of this work, the Social Rhythm Metric (SRM-17) was submitted to a process of adaptation to two different research contexts. In the second part, the scale was used in a clinical study to evaluate the correlation between minor psychiatric symptomatology and the variable social rhythm in a healthy sample. Taking as gold standard SRM-17, were compared scores of regularity and amount of activities of 167 healthy subjects, 25 patients with juvenile myoclonic epilepsy and 16 patients with major depressive disorder, for establishing the Brief Version. In the cross-cultural study, the Brazilian version of the of SRM-17 was submitted to evaluation of 10 college students Angolans, who analyzed the clarity of each of the 15 sentences of the instrument through the Visual Analog Scale-10 cm and proposed modifications. Review of the results was performed for the final version, as well as proof reading and final report. In the clinical study, cross-sectional, were evaluated 143 healthy workers from HCPA. Minor psychiatric symptoms were assessed by the Self-Repport Questionnaire (SRQ-20) and social rhythm was assessed by SRM-17. Light exposure and Sleep variables wereassessed by MCTQ. Results: Was established brief version of 6 items with good agreement with respect to the gold standard (k = 0.51, p <0.001) and significant correlation between the two: (r = 0.87, p <0.001). In the transcultural study was established an angolan version that kept an equivalence of items with respect to Brazilian Portuguese version of SRM-17 and satisfactory degree of clarity and semantic equivalence. In the clinical study, number of activities correlated with schooling and average sleep time and inversely, with Midpoint of sleep (MSF) and SRQ score. Regularity correlated with age, SRQ score and number of days worked. SRQ score correlated inversely with regularity and amount of activities. Conclusions: When establishing of the short version, it was concluded that the simplification of the scale decreases the percentage of unanswered questions, the print cost, and facilitates the standardization. The transcultural study showed that, in spite of the common language in both countries, there are significant cultural differences which can inffluence the results when ignored. The clinical study showed that social rhythm variables were inversely correlated with minor psychiatric symptoms, which were explained more by lower activity levels than low levels of regularity.

O trabalho é considerado um importante zeitgeber social. Objetivo: O objetivo do presente estudo é avaliar o ritmo social de pacientes adultos dependente de crack, internados na Unidade de Adição/ Unidade Álvaro Alvim do Hospital de Clínicas de Porto Alegre. Método: Participaram da pesquisa 50 pacientes dependentes de crack, internados para desintoxicação e reabilitação, aos quais foram aplicados questionários sócio-demográficos que permitiram conhecer a situação social, de moradia, renda, trabalho e emprego, tratamentos prévios e rede sócio-assistencial dos participantes, questionário para avaliação de indivíduos matutinos e vespertinos, escala breve de avaliação de ritmo social e revisão de prontuário. Resultados: A média de idade da amostra foi de 34,6 anos, 54% solteiros, com maior predominância na religião católica (54,3%). Cerca de 40% dos indivíduos contam com renda familiar mensal de 3 salários mínimos ou mais. Dos indivíduos que estão trabalhando ou em benefício do INSS (60%), 14% desenvolve as suas atividades no comércio, e cerca de 12 % trabalham na construção civil. A média da regularidade das atividades desenvolvidas (HITs) ficou em torno de 5,8 e a média do montante de atividades desenvolvidas (ALIs) foi de 33,8. Não Houve diferença significativa na correlação entre abandono de tratamento. Com relação à ritimicidade (5,8), os pacientes internados apresentaram um alto índice de regularidade, comparados com pessoas sem uso de drogas não internadas (4,2).1. Não foi encontrada relação entre o cronotipo dos participantes e o resultado dos HITs e ALIs. Conclusão: Apesar de ser mencionado o trabalho como um dos principais motivos para abandono de tratamento, os resultados deste trabalho não sustentam esta premissa. A situação de trabalho e a profissão não estão associadas ao abandono prévio de tratamento. Por outro lado, contrariando nossa hipótese inicial, a escolaridade aparece de maneira significativa, sendo evidenciado que quanto maior a escolaridade maior o índice de abandono precoce. A relação entre HITs e ALIs sugere que quanto mais atividades desenvolvidas, maior a regularidade com que elas foram realizadas durante a internação. No entanto, estudos futuros de segmento serão necessários para avaliar a manutenção desta regularidade. / Work is considered an important social zeitgeber. Objective: The aim of this study is describe the social rhythm of adult crack-cocaine users that are hospitalized in the Addiction Treatment Unite of the Hospital of Clinics of Porto Alegre. Method: 50 crack-cocaine users were interviewed after admission for detoxification and rehabilitation. We performed interviews with socio-demographic questionnaires that allowed us to access the social characteristics, housing, income, labor and employment, previous treatments and social assistance network. Also, they answer to a instrument to identify which individuals were morning or evening subjects, the Brief Social Rhythm Scale and chart review were assessed. Results: Mean age of the sample was 34.6 years old, and 54% of individuals reported to be single with predominance in the Catholic religion (54.3%). About 40% of the sample have a monthly family income of three minimum wages or more. Among individuals who are currently working or receive a benefit from Government (60%), 14% develop their activities in trade and 12% work in construction. The average of regularity of activities performed inside the inpatient unit (HITs) was around 5.8 and the average of amount of activities performed inside the inpatient unit (ALIs) was 33.8. There was no significant difference in the correlation between treatment dropout and rhythmicity. Regarding rhythmicity (5.8), hospitalized patients reported high levels of regularity when compared to individuals who were not hospitalized, neither had drug use (4.2) .1 We did not find a correlation between participant’s chronotipes and HITs and ALIs results. Conclusion: Despite work is cited as a major reason for treatment dropout, the results of this study do not support this premise. Work situation and the profession are not associated with prior treatment dropout. Contrary to our initial hypothesis, schooling appears as an important issue because it is significantly associated to early treatment dropout. The relationship between HITs and ALIs suggests that the more activities were developed, the greater the regularity with which they were performed during hospitalization. However, future follow-up studies are needed to evaluate the maintenance of this regularity.

Introdução: Interações sociais podem afetar diretamente ritmos biológicos, independente de seu papel na organização do zeitgeber fótico. A força do zeitgeber social refere-se ao padrão rítmico das interações sociais e pode ser quantificada através da escala de ritmo social. Objetivos: Principais: 1. Adequar o instrumento de avaliação do ritmo social ao contexto de pesquisa. 2. Estudar o ritmo social em humanos. Secundários: 1. Estabecer uma versão abreviada da Escala de Ritmo Social com vistas à aplicação em pesquisa. 2. Estabelecer uma versão da Escala de Ritmo Social de 17 itens para o português angolano, para estudos transculturais. 3. Investigar a correlação entre ritmo social, fase do sono e sintomas psiquiátricos menores em trabalhadores saudáveis. Métodos: Na primeira parte do trabalho a Escala de Ritmo Social (ERS-17) foi submetida a um processo de adequação a dois contextos de pesquisa diferentes. Na segunda parte, a escala foi utilizada em um estudo clínico para avaliar a correlação entre sintomatologia psiquiátrica menor e a variável ritmo social em uma amostra saudável. Tomando como padrão-ouro a ERS-17, foram comparados escores de regularidade e quantidade de atividades de 167 sujeitos saudáveis, 25 portadores de epilepsia mioclônica juvenil e 16 portadores de transtorno depressivo, para o estabelecimento da Versão Breve. No estudo transcultural, a versão brasileira da Escala de Ritmo Social foi submetida à avaliação de 10 estudantes universitários angolanos, que analisaram o grau de clareza de cada uma das 15 sentenças do instrumento por meio da Escala Analógico-Visual de 10 cm e propuseram modificações na escala. Foi realizada revisão dos resultados para a elaboração da versão final, bem como prova de leitura e relatório final. No estudo clínico, transversal, foram avaliados 143 trabalhadores saudáveis do HCPA. Sintomas psiquiátricos menores foram avaliados pelo Self-Repport Questionnaire (SRQ-20), e ritmo social foi avaliado pela ERS-17. Exposição à luz e variáveis do sono foram avaliadas pelo Munich Choronotype Questionnaire (MCTQ). Resultados: Foi estabelecida uma versão breve de 6 itens com boa concordância com relação ao padrão-ouro k=0,51; p<0,001 e significativa correlação entre ambas: (r=0,87; p<0,001). No estudo transcultural foi estabelecida uma versão angolana que manteve uma equivalência de itens com relação à versão em português brasileiro e grau satisfatório de clareza e equivalência semântica. No estudo clínico, Quantidade de atividades correlacionou com escolaridade e tempo médio do sono e, inversamente, com (Ponto Médio do Sono) MSF e SRQ-20. Regularidade correlacionou com idade, SRQ-20 e número de dias trabalhados. SRQ-20 correlacionou inversamente com regularidade e quantidade de atividades. Conclusões: No estabelecimento da versão breve, concluiu-se que a simplificação da escala diminui a porcentagem de itens não preenchidos, o custo em material impresso e facilita a padronização. O estudo transcultural demonstrou que apesar de ser o Português o idioma oficial nos dois países, há diferenças culturais significativas que podem influenciar os resultados caso sejam ignoradas. O estudo clínico demonstrou que variáveis de ritmo social tiveram correlação inversa com sintomas psiquiátricos menores, que foram mais explicados por baixos níveis de atividade do que por baixos níveis de regularidade. / Background: Social rhythms can directly affect biological rhythms, independent of its role in organizing the photic zeitgeber. The strength of the social zeitgeber refers to the rhythmic pattern of social interactions and can be measured by Social Rhythm Metric. Objectives: Main Objectives: 1. To match the assessment tool of social rhythm to the research context. 2. To Study the social rhythm in humans. Secondary Objectives: 1. Establish an abbreviated version of the Social Rhythm Metric-17 for use in research. 2. Establish a version of the SRM-17 for the Angolan Portuguese, for cross-cultural studies. 3. To investigate the correlation between social rhythm, sleep phase and minor psychiatric symptoms in healthy workers. Methods: In the first part of this work, the Social Rhythm Metric (SRM-17) was submitted to a process of adaptation to two different research contexts. In the second part, the scale was used in a clinical study to evaluate the correlation between minor psychiatric symptomatology and the variable social rhythm in a healthy sample. Taking as gold standard SRM-17, were compared scores of regularity and amount of activities of 167 healthy subjects, 25 patients with juvenile myoclonic epilepsy and 16 patients with major depressive disorder, for establishing the Brief Version. In the cross-cultural study, the Brazilian version of the of SRM-17 was submitted to evaluation of 10 college students Angolans, who analyzed the clarity of each of the 15 sentences of the instrument through the Visual Analog Scale-10 cm and proposed modifications. Review of the results was performed for the final version, as well as proof reading and final report. In the clinical study, cross-sectional, were evaluated 143 healthy workers from HCPA. Minor psychiatric symptoms were assessed by the Self-Repport Questionnaire (SRQ-20) and social rhythm was assessed by SRM-17. Light exposure and Sleep variables wereassessed by MCTQ. Results: Was established brief version of 6 items with good agreement with respect to the gold standard (k = 0.51, p <0.001) and significant correlation between the two: (r = 0.87, p <0.001). In the transcultural study was established an angolan version that kept an equivalence of items with respect to Brazilian Portuguese version of SRM-17 and satisfactory degree of clarity and semantic equivalence. In the clinical study, number of activities correlated with schooling and average sleep time and inversely, with Midpoint of sleep (MSF) and SRQ score. Regularity correlated with age, SRQ score and number of days worked. SRQ score correlated inversely with regularity and amount of activities. Conclusions: When establishing of the short version, it was concluded that the simplification of the scale decreases the percentage of unanswered questions, the print cost, and facilitates the standardization. The transcultural study showed that, in spite of the common language in both countries, there are significant cultural differences which can inffluence the results when ignored. The clinical study showed that social rhythm variables were inversely correlated with minor psychiatric symptoms, which were explained more by lower activity levels than low levels of regularity.