It is important to evaluate periodic fluctuations in environment or climate recorded through time to better understand the nature of Earth's history as well as to develop ideas about what the future may hold. There exist numerous proxies by which these environmental patterns can be demonstrated and analyzed through various time scales; from sequence stratigraphic bundles of transgressive-regressive cycles that demonstrate eustatic changes in global sea level, to the geochemical composition of a skeleton that records fluctuations in ocean temperature through the life of the biomineralizing organism. This study examines some of the methods by which we can analyze environmental fluctuations recorded at different time scales. The first project examines the methods by which extrabasinal orbital forcing (i.e. Milankovitch cycles) can be tested in the rock record. In order to distinguish these patterns, computer generated carbonate rock records were simulated with the resulting outcrops tested using common methods. These simulations were built upon eustatic sea level fluctuations with periods similar to what has been demonstrated in the rock record, as well as maintaining the many factors that affect the resultant rock composition such as tectonics, subsidence, and erosion. The result demonstrated that substantially large sea level fluctuations, such as those that occur when the planet is in an icehouse condition, are necessary to produce recognizable and preservable patterns that are otherwise overwhelmed by other depositional factors. The second project examines the temporal distribution of the bivalve Semele casali from Ubatuba Bay, Brazil by using amino acid racemization (AAR) calibrated with ¹⁴C radiometric dates. This data set is one of the largest ever compiled and demonstrates that surficial shell assemblages in the area have very long residence times extending back in time 10,000 years. The area has had very little change in sea level and the AAR ratios which are highly temperature dependent could be calibrated across sites varying from 10 to 53 meters in water depth. Long time scales of dated shells provide us with an opportunity to study climate fluctuations such as El Niño southern oscillation. The third project describes a newly developed method for estimating growth rates in organisms using closely related species from similar environments statistically analyzed for error using a jackknife corrected parametric bootstrap. As geochemical analyses get more precise while using less material, data can be collected through the skeleton of a biomineralizing organism, thus revealing information about environmental shifts at scales shorter than a year. For such studies, the rate of growth of an organism has substantial effects on the interpretation of results, and such rates of growth are difficult to ascertain, particularly in fossilized specimens. This method removes the need for direct measures of growth rates and even the most conservative estimates of growth rates are useful in constraining the age ranges of geochemical intra-skeletal studies, thus elucidating the likely time period under analysis. This study assesses the methods by which periodic environmental fluctuations at greatly varying time scales can be used to evaluate our understanding of earth processes using rigorous quantitative strategies. / Ph. D.

Stress hormones, adrenaline and noradrenaline, have been shown to be critical for heart development. Mice lacking dopamine greek lower case letter beta]-hydroxylase (Dbh), an enzyme responsible for synthesis of these adrenergic hormones, die during mid-gestation due to cardiac failure. Prior research showed that adrenergic cells are found within the electrical conduction system of the heart, and adrenergic deficiency leads to slowed cardiac conduction during embryogenesis. Microarray analysis of wild-type (Dbh+/+) and knockout (Dbh-/-) mouse hearts revealed significant differences in expression of retinoic acid (RA) signaling genes. RA signaling has also been shown to be critical for heart development. These data suggest that heart failure due to adrenergic deficiency may be dependent upon RA signaling. This led to the hypothesis that adrenergic hormones promote the development of the electrical conduction system through modulation of RA signaling. To test this, embryonic mouse hearts were cultured with LE 135, a RA receptor blocker. Heart rate, arrhythmic index (AI) and conduction time were measured. Under these conditions there was a marked increase in arrhythmias. Hearts treated with LE 135 showed a mean AI of 0.232±0.057 after 24 hours of treatment while when untreated had an AI of 0.083±0.028 (p<0.05;n=15). In contrast, there was no significant change in heart rate or conduction speed after 24 hours with or without the retinoic acid receptor blocker. To determine if adrenergic stimulus influences retinoic acid response, an established RA-sensitive reporter cell line was employed. These F9-RARE-LacZ cells were treated with forskolin (cAMP regulator) and isoproterenol (greek lower case letter beta]-agonist) to measure changes in RA signaling. Evaluation of RA signaling showed an increase in retinoic acid responsiveness when treated with an adrenergic signaling agonist.; These results suggest that proper retinoic acid signaling is essential for maintaining cardiac rhythmicity during embryonic development and adrenergic stimulation can influence this response.

Esponjas (filo Porifera) são consideradas representantes atuais dos primeiros metazoários, com origens evolutivas próximas da transição de uma organização unicelular para aquela multicelular. Toda sua fisiologia é baseada em células especializadas, sem órgãos ou tecidos verdadeiros como encontrados em outros animais. No entanto, a presença de um sistema fortemente integrado pode ser constatada em sua habilidade de contrair o corpo de maneira rítmica e coordenada, ainda que a dinâmica e o controle desse processo sejam pouco conhecidos. Neste trabalho, análises de imagens em time-lapse sob um ciclo claro-escuro (12:12h) e sob luz constante mostram que as espécies Hymeniacidon heliophila e Tethya maza exibem padrões distintos de contrações corpóreas rítmicas, com variações circadianas em suas amplitudes. Diferenças observadas nos perfis das curvas das duas espécies podem ser devidas a diferenças em seus habitats de origem e/ou a diferenças em suas estruturas corpóreas. A manutenção desses ritmos sob luz constante indica a presença de um relógio endógeno em ambos os animais. Entre as vias envolvidas na sinalização desses processos a mais ubíqua é a da melatonina, um hormônio cuja presença tem sido demostrada em muitos filos animais, dos quais o mais basal é o Cnidaria. Considerando a ampla ação da melatonina como um sinalizador circadiano e a ausência de um sistema nervoso em esponjas, não seria surpreendente constatar um papel da molécula na coordenação dos movimentos desses animais. Ademais, o papel da molécula nas respostas imunes também já foi demonstrado ser de ampla distribuição. Nossas tentativas de revelar uma ação da molécula na reagregação celular de H. heliophila via receptores do tipo MT1 e MT2 não foram conclusivas. Alguns fatores que podem ter influenciado nas respostas divergentes da molécula são o estado imunitário e a presença de contaminantes no ambiente de origem do animal. Ainda, outros mecanismos de ação e/ou processos candidatos à ação da melatonina não devem ser descartados. Ainda que preliminares, nossos resultados são o primeiro relato da presença da melatonina no filo mais basal dentre os Metazoa / Sponges (phylum Porifera) are considered current representatives of the first metazoans, with evolutionary origins close to the transition from a unicellular to a multicellular organization. All of its physiology is based on specialized cells, without organs or real tissues as found in other animals. However, the presence of a strongly integrated system can be verified in its ability to contract the body in a rhythmic and coordinated way, althouth the dynamic and the control of this process are little known. In this work, time-lapse image analysis under a light-dark cycle (12:12h) and constant light shows that the species Hymeniacidon heliophila and Tethya maza display different patterns of body contractions, with circadian variations in their amplitudes. These dissimilar contraction profiles of the two species can be due to their original habitats and/or in their body structures. The maintenance of these rhythms under constant light indicates the presence of an endogenous clock in both animals. Among the pathways that participate in this process the most ubiquitous is that of melatonin, a hormone whose presence has been demonstrated in several animals phyla, of which the most basal until now is Cnidaria. Considering the melatonin action as a circadian signal and the absence of a nervous system in sponges, it would not be surprising that this molecule participates in coordination in these animals. In addition, the melatonin role in the immune responses has also been shown to be widely distributed. Our attempts to reveal a molecule action in the H. heliophila cellular reaggregation via MT1 and MT2 receptors were inconclusive. Some of the factors that may have influenced the molecule divergent responses are the immunity condition and the presence of contaminants in the original environment of the animals. Still, other mechanisms and/or processes that are candidates for melatonin action should not be discarded. Although preliminary, our results are the first report of the presence of melatonin in the most basal phylum among the Metazoa

In the present thesis, Jane and Louisa Will Soon Come Home, the novel by the Jamaican writer Erna Brodber, is analyzed in the context of post-colonial identity trauma. Analyzing the complex organizational and narrative structure of the novel, the essay author studies how the novel’s rhythmicity and the broken narrative portray the protagonist’s identity fragmentation. Drawing on the work’s connection to the ring game played in the Caribbean and applying the symbolism of the Caribbean folk rhythms, the essay author discusses the subversive intent of Brodber’s novel and her method of rewriting the past as a way of recovering one's identity.

Esponjas (filo Porifera) são consideradas representantes atuais dos primeiros metazoários, com origens evolutivas próximas da transição de uma organização unicelular para aquela multicelular. Toda sua fisiologia é baseada em células especializadas, sem órgãos ou tecidos verdadeiros como encontrados em outros animais. No entanto, a presença de um sistema fortemente integrado pode ser constatada em sua habilidade de contrair o corpo de maneira rítmica e coordenada, ainda que a dinâmica e o controle desse processo sejam pouco conhecidos. Neste trabalho, análises de imagens em time-lapse sob um ciclo claro-escuro (12:12h) e sob luz constante mostram que as espécies Hymeniacidon heliophila e Tethya maza exibem padrões distintos de contrações corpóreas rítmicas, com variações circadianas em suas amplitudes. Diferenças observadas nos perfis das curvas das duas espécies podem ser devidas a diferenças em seus habitats de origem e/ou a diferenças em suas estruturas corpóreas. A manutenção desses ritmos sob luz constante indica a presença de um relógio endógeno em ambos os animais. Entre as vias envolvidas na sinalização desses processos a mais ubíqua é a da melatonina, um hormônio cuja presença tem sido demostrada em muitos filos animais, dos quais o mais basal é o Cnidaria. Considerando a ampla ação da melatonina como um sinalizador circadiano e a ausência de um sistema nervoso em esponjas, não seria surpreendente constatar um papel da molécula na coordenação dos movimentos desses animais. Ademais, o papel da molécula nas respostas imunes também já foi demonstrado ser de ampla distribuição. Nossas tentativas de revelar uma ação da molécula na reagregação celular de H. heliophila via receptores do tipo MT1 e MT2 não foram conclusivas. Alguns fatores que podem ter influenciado nas respostas divergentes da molécula são o estado imunitário e a presença de contaminantes no ambiente de origem do animal. Ainda, outros mecanismos de ação e/ou processos candidatos à ação da melatonina não devem ser descartados. Ainda que preliminares, nossos resultados são o primeiro relato da presença da melatonina no filo mais basal dentre os Metazoa / Sponges (phylum Porifera) are considered current representatives of the first metazoans, with evolutionary origins close to the transition from a unicellular to a multicellular organization. All of its physiology is based on specialized cells, without organs or real tissues as found in other animals. However, the presence of a strongly integrated system can be verified in its ability to contract the body in a rhythmic and coordinated way, althouth the dynamic and the control of this process are little known. In this work, time-lapse image analysis under a light-dark cycle (12:12h) and constant light shows that the species Hymeniacidon heliophila and Tethya maza display different patterns of body contractions, with circadian variations in their amplitudes. These dissimilar contraction profiles of the two species can be due to their original habitats and/or in their body structures. The maintenance of these rhythms under constant light indicates the presence of an endogenous clock in both animals. Among the pathways that participate in this process the most ubiquitous is that of melatonin, a hormone whose presence has been demonstrated in several animals phyla, of which the most basal until now is Cnidaria. Considering the melatonin action as a circadian signal and the absence of a nervous system in sponges, it would not be surprising that this molecule participates in coordination in these animals. In addition, the melatonin role in the immune responses has also been shown to be widely distributed. Our attempts to reveal a molecule action in the H. heliophila cellular reaggregation via MT1 and MT2 receptors were inconclusive. Some of the factors that may have influenced the molecule divergent responses are the immunity condition and the presence of contaminants in the original environment of the animals. Still, other mechanisms and/or processes that are candidates for melatonin action should not be discarded. Although preliminary, our results are the first report of the presence of melatonin in the most basal phylum among the Metazoa

The thesis deals with the socio-spatial transformation of the Prague district Karlin. This post- socialist and post-industrial developing dynamic district has changed its character in the recent decades. I follow on from the post-socialist theories that perceive the city of the so- called hybrid perspectives. These theories reveal it as a whole and take into account the everyday experience of the changing city. I describe these experiences of the inhabitants and visitors of Karlin with the concepts of social production and social construction, which combine the macroanalysis of social, economic and political influences and the microanalysis of individual living experience. I work on the assumption at the same time that the socio- spatial change manifests itself in the everyday activities of people and their rhythmicity which is the result of social construction and the production of urban space. The aim of the thesis is to describe the socio-spatial change through the example of Karlin Square with the analysis of rhythmicity. I use several qualitative methods of urban studies. In particular, I use the following methods: semi-structured interviews with mental mapping, participating observations and diaries

La communication entre les neurones est fondée sur leur capacité à changer leur patron de décharge pour l’encodage de différents messages. Pour plusieurs fonctions vitales, comme la respiration et la mastication, les neurones doivent pouvoir générer des patrons d’activité répétitifs, et les groupes de neurones responsables de ces décharges rythmiques sont des générateurs de patron central (GPC). En dépit de recherches soutenues, les mécanismes précis qui sous-tendent la rythmogénèse dans les GPCs ne sont pas bien définis. Le plus souvent, la potentielle contribution des astrocytes demeure grandement inexplorée, même si ces cellules sont aujourd’hui connues pour leur implication dans la modulation synaptique neuronale. Pour nos travaux, le noyau sensoriel principal du trijumeau (NVsnpr) a été pris comme modèle à cause de son rôle central dans les mouvements rythmiques de la mastication. Dans ce noyau, des travaux antérieurs ont montré que la décharge en bouffées rythmiques est déclenchée dans les neurones lorsque la concentration de calcium extracellulaire ([Ca2+]e) est artificiellement baissée. Nous fondant sur cette observation, notre première hypothèse a postulé que la baisse de la [Ca2+]e pouvait survenir de façon physiologique en lien avec des stimulations sensorielles pertinentes. Deuxièmement, parce que les astrocytes ont été impliqués dans le tamponnage et l’homéostasie d’ions extracellulaires comme le K+, nous avons postulé que ces cellules pouvaient jouer un rôle équivalent dans le contrôle de la [Ca2+]e. Nos résultats montrent que les astrocytes peuvent réguler la [Ca2+]e et ainsi contrôler la capacité des neurones à changer leur patron de décharge. Premièrement, en stimulant les afférences sensorielles au NVsnpr, nous avons montré que des baisses physiologiques de la [Ca2+]e sont observées en parallèle à l’apparition de bouffées rythmiques neuronales. Deuxièmement, nous avons démontré que les astrocytes répondent aux mêmes stimuli qui induisent l’activité rythmique neuronale, et que leur blocage avec un chélateur de Ca2+ empêche les neurones de générer un patron de décharge en bouffées rythmiques. Cette habilité est rétablie en rajoutant la S100β, une protéine astrocytaire liant le Ca2+, dans le milieu extracellulaire, alors que l’anticorps anti-S100β empêche l’activité rythmique. Ces résultats indiquent que les astrocytes régulent une propriété neuronale fondamentale : la capacité à changer de patron de décharge. Ainsi, les GPCs dépendraient des fonctions intégrées des astrocytes et des neurones. Ces découvertes pourraient avoir des implications transposables à plusieurs autres circuits neuronaux dont la fonction dépend de l’induction d’activité rythmique. / Communication between neurons rests on their capacity to change their firing pattern to encode different messages. For several vital functions, such as respiration and mastication, neurons need to generate a repetitive firing pattern, and the groups of neurons responsible for these rhythmic discharges are called central pattern generator (CPG). Despite intense research in this field, the exact mechanisms underlying rhythmogenesis in CPGs are not completely defined. In most instances, the potential contribution of astrocytes is largely unexplored, even though these cells are now well known to be involved in neuronal synaptic modulation. In our work, the trigeminal main sensory nucleus (NVsnpr) was used as a model owing to its central role in the rhythmic movement of mastication. Previous work have shown that rhythmic bursting discharge is triggered in NVsnpr neurons when extracellular calcium concentration ([Ca2+]e) is artificially decreased. Based on this observation, our first hypothesis postulated that the reduction of [Ca2+]e could also happen physiologically in relation to relevant sensory stimulation. Secondly, because astrocytes have been involved in the buffering and the homeostasis of extracellular ions like potassium, we have postulated that these cells could also play a role in the control of [Ca2+]e. The results presented in this thesis show that astrocytes can regulate [Ca2+]e and thus control the ability of neurons to change their firing pattern. First, we showed that stimulation of sensory afferent fibers to the NVsnpr induced neuronal rhythmic bursting and in parallel reduction of [Ca2+]e . Secondly, we have demonstrated that astrocytes respond to the same sensory stimuli that induce neuronal rhythmic activity, and their blockade with a Ca2+ chelator prevents generation of neuronal rhythmic bursting. This ability is restored by adding S100β, an astrocytic Ca2+-binding protein, to the extracellular space, while the application of an anti- S100β antibody prevents generation of rhythmic activity. These results indicate that astrocytes regulate a fundamental neuronal property: that is the capacity to change their firing pattern. Thus, CPG functions result from integrated neuronal and glial activities. These findings may have broad implications for many other neural networks whose functions depend on the generation of rhythmic activity.

Background Although trainers and athletes consider ‘good timing skills’ to be critical for optimal sport performance, little is known in regard to how sport-specific skills may benefit from timing training. Thus, assuming that all motor performances are mediated by an internal timing mechanism, enhanced motor timing is expected to have positive effects on both planning and execution of movement performance, and consequently on complex sports actions as golf or soccer. Accordingly, in order to increase our knowledge of the importance of motor timing and possible effects of timing training, this thesis examines the effects of synchronized metronome training (SMT), thought to improve the execution of motor programs and to enhance motor skills in golf and soccer players. Methods Study I examined the effects of SMT on motor timing abilities and its potential effect on golf shot accuracy and consistency in 25 experienced male golfers. Additionally, Study II examined the effects of SMT on the spatiotemporal movement organisation and dynamics of the golf swing performance, as captured by kinematic measurements and analyses in thirteen male golfers. Study III examined the effect of SMT on accuracy and variability in a soccer specific, cross-pass task in elite and sub-elite female soccer players. Moreover, the underlying brain activity was assessed by means of functional magnetic resonance imaging (fMRI) to investigate the corresponding neural activity when passively observing the cross-pass task, and the possible pre- to post training effects. Results SMT was shown to improve motor timing ability, by means of less timing asynchrony and with associated changes in timing variability, in both golf- and soccer-players. Additionally, significant improvements in golf shot and soccer cross-pass performance, by means of significant increase in outcome accuracy combined with a decrease in outcome variability was found. From the kinematic investigation in Study II, results indicate that improved motor timing, as an effect of SMT, lead to a more coordinated and dynamic swing performance, and with decreased variability in the temporal structure of the swing motion. Finally, it was found that SMT induces changes in the activity of the action observation network (AON), underpinning action observation and action prediction, by means of decreased activation within bilateral cerebellum, fusiform gyrus and superior temporal gyrus. These findings hint at a more efficient pattern of neural recruitment during action observation, after SMT. Conclusion In summary, this thesis provides evidence that four weeks of SMT improved the participant’s motor timing and synchronization abilities, and showed influence on both behavioral and neurophysiological motor programs and skill performance in golf and soccer players. Thus, by improved outcome accuracy and decreased variability, affecting the coordinated movement pattern and organisation, as well as affecting the associated underlying brain activation.

Made available in DSpace on 2012-09-06T01:11:30Z (GMT). No. of bitstreams: 2 license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) 117.pdf: 1157899 bytes, checksum: 6f6021820b6176fcba6db85081d29000 (MD5) Previous issue date: 1998 / O organismo humano apresenta uma ritmicidade de eventos bioquímicos, fisiológicos e comportamentais durante as 24 horas do dia, fazendo com que o mesmo tenha peculiaridades distintas nos diferentes horários diurnos e noturnos. Esta ritmicidade circadiana encontra-se intimamente ligada a sincronizadores externos: ciclo claro/escuro; ritmos sociais; a organizaçäo temporal da atividade laborativa do indivíduo, dentre outros. A organizaçäo temporal do trabalho dos aeronautas caracteriza-se pela alternância dos seus turnos, o que em última análise, significa dizer que este trabalhador muitas vezes desempenha suas atividades profissionais em diferentes momentos do dia e da noite. Esta inversäo de horários de repouso por momentos de trabalho acarreta alteraçöes na ritmicidade biológica. Objetiva-se investigar a percepçäo de comandantes, da aviaçäo civil brasileira, que realizam jornadas transmeridionais sobre as repercussöes que estas condiçöes de trabalho podem ter sobre sua saúde. Para a coleta dos dados, foram distribuídos questionários para todos os comandantes de Boeing 767 da base Rio de Janeiro, das companhias VARIG e Transbrasil. Do total de 87 questionários enviados, obteve-se um retorno de 25. Os resultados demonstraram que as condiçöes de trabalho dos comandantes apresentam sérias e inúmeras implicaçöes sobre a sua saúde. A sensaçäo de fadiga, as alteraçöes do ciclo sono-vigília e dos hábitos alimentares e o afastamento familiar foram os fatores que mais apareceram no relato dos comandantes como sendo os mais comprometidos, causando consequências como sonolência, distúrbios gratrointestinais, comprometimentos na vida familiar como divórcios, dentre outros. Com o intuito de minimizar estes sintomas, os comandantes desenvolveram algumas estratégias como dormir assim que chegam ao local de destino, praticar algum tipo de atividade física e seguir os horários do local, que säo utilizadas com frequência e, segundo seus próprios relatos, com êxito no que se propöem. / The human body presents a rhythmicity of biochemical, physiological and behavioral events throughout the 24 hours of a day. It means that this body has different peculiarities during the day and others at night. This circadian rhythmicity is closely linked to “zeitgebers” (external synchronizers): sleep/wake cycle, social rhythms, shiftwork and so on. One of the most important characteristics within the aviation profession is the alternation of shifts, which means that the aeronauts have to develop their professional activities at different hours of the day and night. This inversion of work periods in lieu of resting ones results in rhythmicity changes. The aim of this study was to investigate the perception of Brazilian civil aviation captains and the influences of their type of work conditions upon their health. The data collection was made using questionnaires which were distributed to all Rio de Janeiro-based Boeing 767 captains employed by VARIG and Transbrasil during the research period. From all the 87 questionnaires sent, 25 returned. The results showed that flight captains` working conditions present several and serious implications on their health. The fatigue, the changes both in the sleep/wake cycle and in the eating habits and the deleterious effects on social events were the aspects cited by the captains as being the most affected ones causing consequences like sleepiness, gastro-intestinal disturbances, relationship difficulties, among others. In order to minimize these symptoms the captains developed some strategies like sleeping as soon as they arrive at their destination, practicing some physical activities and following the local time, which are used very often and successfully.