Προδρομικές και αναδρομικές μελέτες έχουν κατά το παρελθόν αναδείξει ένα ευρύ φάσμα προδρόμων συμπτωμάτων. Ωστόσο η σχέση των προδρόμων αυτών συμπτωμάτων με αυτά της ενεργού ψύχωσης δεν έχει διερευνηθεί επαρκώς. Σε 73 νοσηλευθέντες ασθενείς με σχιζοφρένεια στο πρώτο ή το δεύτερο ψυχωτικό επεισόδιο και με διάρκεια νόσου ≤ 3 έτη (DSM-IV-TR, Axis I διάγνωση), μετρήθηκε η βαρύτητα του επεισοδίου με τη χρήση της Κλίμακας για το Αρνητικό και το Θετικό σύνδρομο (PANSS), εντός 5 ημερών από τη έναρξη του επεισοδίου. Αναζητήθηκαν επίσης αναδρομικά τα πρόδρομα συμπτώματα της νόσου. Η ανάλυση με κατά βήματα παλινδρόμηση έδειξε ότι 8 πρόδρομα συμπτώματα έφεραν αυξημένο κίνδυνο για υψηλή τιμή PANSS (ολική ή/και υποκλίμακες ), ανεξάρτητα του φύλου, ενώ ένα σύμπτωμα συσχετίστηκε με ήπια ψυχοπαθολογία. Ωστόσο τα αρνητικά και τα θετικά-αποδιοργανωτικά πρόδρομα συμπτώματα δεν συσχετίζονταν με τα αντίστοιχα συστατικά της PANSS. Παρόμοια ευρήματα παρατηρήθηκαν στους μη παρανοϊκούς ασθενείς, ενώ στους παρανοϊκούς μόνο 2 μη ειδικά πρόδρομα συμπτώματα συσχετίστηκαν με υψηλή ψυχοπαθολογία. Επίσης υπήρξαν σημαντικές συσχετίσεις ανάμεσα στον αριθμό των προδρόμων συμπτωμάτων και στα σκορ της PANSS (ολικής κλίμακας, θετικής και γενικής υποκλίμακας) στους ασθενείς με μη παρανοϊκό υπότυπο όχι όμως και στους ασθενείς με παρανοϊκό υπότυπο. Συμπερασματικά αρκετά πρόδρομα συμπτώματα, αλλά και ο αριθμός των συμπτωμάτων της πρόδρομης φάσης σχετίζεται με τη σοβαρότητα της ψυχοπαθολογίας της ενεργού ψύχωσης. Στους μη παρανοϊκούς ασθενείς υπάρχει συνέχεια στη μετάβαση από την προψυχωτική στη ψυχωτική φάση, ενώ στους παρανοϊκούς η μετάβαση αυτή διακόπτεται. / Both retrospective and prospective studies have identified a broad spectrum of ‘‘prodromal’’ symptoms, but their relationship to those of frank psycho¬sis remains largely unexplored. In 73 successive hospitalized schizophrenia patients in the first or second psychotic episode and with duration of illness ≤ 3years from the onset of psychosis were made DSM-IV-TR, Axis I, diagnoses. Also, within the first 5 days from the psychotic episode’s onset, symptom severity was assessed with the Positive and Negative Syndrome Scale (PANSS). Patients were interviewed for the presence of ‘‘prodromal’’ symptoms retrospectively. Stepwise regression analyses showed that 8 prodromal symptoms carried an increased risk for high total PANSS and the components of the PANSS scores, independently of gender; one symptom was associated with mild psychopathology. However, the categories of negative and positive-disorganization prodromal symptoms were not associated with the corresponding PANSS components. Similar findings were observed in the nonpa¬ranoid patients, whereas in the paranoid only 2 nonspecific symptoms were associated with high PANSS psychopathology. Also, there were significant associations between number of prodromal symptoms and total PANSS and the subscales positive and general scores in the patients with the nonparanoid subtypes, but there were not such associations in those with the paranoid. In conclusion several prodromal symptoms as well as the number of symptoms are associated with the severity of the psychopathology of frank psychosis. In the nonpa¬ranoid subtypes there is a continuance in the transition from the prepsychotic to the psychotic stage, whereas in the paranoid the transition appears to be disrupted.

This study proposes an approach for solving density-based multi-material topology optimization of cracked structures using Peridynamics. The alternating active-phase algorithm is utilized to transform the multi-material problem into a series of binary phase topology optimization sub-problems. Instead of the conventional mesh-based methods, the Peridynamics theory (PD) is used as a tool to model the behaviour of the materials and solve for the displacement field. The most significant advantage of PD is its ability to model discontinuities in a relatively straightforward manner. Thus, in the present work, the effect of cracks as a discontinuity is investigated on the optimal multi-material topologies. The Solid Isotropic Material with Penalty (SIMP) method is utilized to define the material properties as a function of the design variables. Also, the optimization problem is solved through the Optimality Criteria (OC) approach. The proposed method is compared to the results reported in the literature by executing three numerical examples that investigate the effect of the direction of an interior crack on the optimal topologies. Moreover, the efficiency of the proposed approach is verified by solving several examples where we aim at minimizing the compliance of the structure with and without initial cracks. / Graduate

Introduction: Pregnancy and childbirth are considered complex and important for the woman and her family phenomena, since they involve psychological, physical, social, economic and cultural aspects. In childbirth, currently, there is a lack of attitudes, behaviors and decision making that benefit the maternal-fetal dynamics, regardless of the medical and nursing interventions that may occur. Thus, observing the complexity of events and changes that the pregnant woman experiences during pregnancy and especially during labor, it is believed that a greater emphasis should be given to multidisciplinary and multi-professional perspective on this tour, aimed at greater possibility of range of comprehensive care. In this sense, it highlights the importance of integrating physical therapist in obstetrics team may contribute significantly to pain relief, advising on the different positions that can be adopted, suggesting exercises and most suitable among other aspects breathing patterns. Objectives: To evaluate the influence of physiotherapy intervention in the progression of active phase of labor, in pain perception during labor in fetal and use of Transcutaneous Electrical stimulation during labor. Methods: Participants were 80 pregnant women divided into three groups, control (n=40), with experimental use of Transcutaneous electrostimulation (TENS, n=20) and without the use of experimental TENS (n=20). The two experimental groups received physical therapy during labor and delivery, but in one of them the use of TENS occurred in conjunction with other physiotherapy techniques. While the CG received routine care from inpatient obstetric unit. All participants were given general guidelines on labor and delivery provided by the physiotherapist. Results: It was observed that there was a decrease of approximately two hours at the time of the active phase in the GE group, with and without TENS, with respect to the GC, as well as decreased pain perception during labor, but not a significant difference was observed regarding the vitality of newborns in the three groups. Conclusion: The results suggest that physical therapy contributed to shorter labor without influencing conceptual vitality at birth, which occurred a decrease in pain perception of physiotherapy intervention in pregnant women during the active phase of labor (TP), that the mothers of GE, with and without TENS were more peaceful, confident and participatory during the TP, although this was an empirical observation, that the use of the TENS did not influence the time of PD as well as in fetal birth. / Introdução: A gestação e o parto são considerados fenômenos complexos e importantes para a mulher e a sua família, uma vez que envolvem aspectos psicológicos, físicos, sociais, econômicos e culturais. Na assistência ao parto verifica-se, atualmente, a falta de atitudes, comportamentos e tomadas de decisão que beneficiem a dinâmica materno-fetal, independentemente das intervenções médicas e de enfermagem que eventualmente ocorram. Sendo assim, observando-se a complexidade de acontecimentos e modificações que a gestante vivencia durante a gestação e, principalmente, durante o parto, acredita-se que uma maior ênfase deveria ser dada à perspectiva multidisciplinar e multiprofissional dessa assistência, visando uma maior possibilidade de alcance da integralidade do cuidado. Neste sentido, salienta-se a importância da inserção do fisioterapeuta na equipe obstétrica, podendo contribuir de forma significativa para o alívio da dor, orientando sobre as diferentes posturas que podem ser adotadas, sugerindo exercícios e padrões respiratórios mais adequados dentre outros aspectos. Objetivos: Avaliar a influência da intervenção fisioterapêutica na progressão da fase ativa do parto, na percepção dolorosa ao longo do trabalho de parto, na vitalidade fetal e no uso da Eletroestimulação Transcutânea durante o trabalho de parto. Metodologia: Fizeram parte do estudo 80 parturientes divididas em três grupos, Controle (n=40), Experimental com uso de Eletroestimulação Transcutânea (EET, n=20) e o Experimental sem o uso de EET (n=20). Os dois grupos experimentais receberam atendimento fisioterapêutico durante o trabalho de parto e parto, porém em um deles ocorreu o uso da EET juntamente com as demais técnicas de fisioterapia. Enquanto o GC recebeu os cuidados de rotina da unidade de internação obstétrica. Todas as participantes receberam orientações gerais sobre o trabalho de parto e parto prestadas pela fisioterapeuta. Resultados: observou-se que houve uma diminuição de, aproximadamente, duas horas no tempo de fase ativa nas parturientes do GE, com e sem EET, com relação ao GC, bem como uma menor percepção dolorosa ao longo do trabalho de parto, porém não se observou diferença significativa com relação a vitalidade dos recém-nascidos nos três grupos. Conclusão: Os resultados permitem concluir que a assistência fisioterapêutica contribuiu para um menor tempo de trabalho de parto sem influenciar na vitalidade conceptual ao nascimento; que ocorreu uma diminuição na percepção dolorosa das gestantes sob intervenção fisioterapêutica, durante a fase ativa do trabalho de parto (TP); que as parturientes dos GE, com e sem EET, mostraram-se mais tranquilas, confiantes e participativas durante o período de TP, embora esta tenha sido uma observação empírica; que o uso da EET não influenciou no tempo de TP assim como na vitalidade fetal ao nascimento.

Cette thèse concerne la production et le contrôle d'hologrammes de haute qualité par un modulateur de phase à cristaux liquides (SLM) et l'utilisation de ces hologrammes pour la manipulation d'atomes froids. Ces hologrammes utilisés pour mettre en forme des faisceaux lasers et créer des potentiels dipolaires doivent être de bonne qualité. Or le SLM a des défauts qui peuvent les dégrader. Pour mesurer ces défauts nous avons développé une méthode reposant sur la mesure par polarimétrie de la biréfringence du SLM. La cartographie de biréfringence permet de mesurer l'hologramme en temps réel sans perturber l'expérience en cours. C'est donc une mesure in-situ. Une fois mesurés les défauts sont corrigés par une rétroaction sur la consigne donnée au SLM. Pour le démontrer nous avons créé un défaut artificiel avec un pointeur laser et nous l'avons réduit à λ/7 soit une amélioration de 42 %. Ensuite avec l'objectif d'appliquer des potentiels produit par un SLM aux atomes froids, j'ai dessiné, conçu puis réalisé en partie une expérience basée sur un jet d'atomes froids de rubidium issu d'un MOT-2D. Dans le chapitre correspondant je présente une étude de la faisabilité d'une expérience de guidage du jet d'atomes froids par un mode de Laguerre Gauss désaccordé vers le bleu de la transition. Nous avons montré que dans un tel guide le chauffage par émission spontanée est plus faible que dans un guide gaussien usuel désaccordé vers le rouge de la transition. De plus en réduisant la divergence naturelle du jet issu du MOT-2D nous devrions augmenter le flux d'atomes et améliorer l'efficacité de chargement d'un MOT-3D par un MOT-2D. / This thesis reports on the production and monitoring of high quality holograms generated by a liquid crystal spatial light modulator (SLM), and the application of these holograms to cold atoms manipulation. In order to produce accurate optical potentials by shaping a laser beam we need high quality holograms. Nevertheless SLMs suffer from defects which limit the quality. To measure defects we have developed a method based on polarimetry to get the birefringence map of the SLM. Birefringence mapping is suitable to monitor the hologram without disturbing the on-going experiment. It's an in-situ measurement. After the measurement, defects are corrected by a feedback on the input hologram. As a proof we created an artificial defect with a laser pointer and reduced it to λ/7 which corresponds to a 42% improvement. Our second goal is to apply SLM-shaped potentials to cold atoms, so I designed and did part of an experiment based on a cold atom beam provided by a rubidium 2D-MOT. In the corresponding chapter I've studied the feasibility of guiding the cold atom beam with a blue-detuned Laguerre-Gaussian beam. We showed that in such a guide the spontaneous emission is lower than in the usual red detuned gaussian guide case. Furthermore by reducing the cold atom beam divergence we expect to enhance the atomic flux and improve the loading efficiency of a 3D-MOT from a 2D-MOT.

Certaines missions d'astrophysique embarquent des détecteurs infrarouges ou X qui sont refroidis à des températures subkelvin via un système cryogénique qui comporte soit un bain d'hélium (comme pour Herschel), soit un réfrigérateur Joule-Thomson (comme pour Planck) pour le pré-refroidissement de l'étage subkelvin. Un doigt froid à tube à gaz pulsé ayant les mêmes performances qu'un Joule-Thomson pourrait offrir un certain nombre d'avantages pour les futures chaines cryogéniques (pas de pré-refroidissement nécessaire, simplicité d'intégration, fiabilité accrue).L'objectif de cette thèse concerne l'étude et la réalisation d'un doigt froid à tube à gaz pulsé 4K qui pourrait remplacer une machine Joule-Thomson. Deux principaux axes d'étude ont été menés parallèlement : des études sur les matériaux régénérateur et des études de performances. Des développements technologiques portant sur le régénérateur (étude et mise en forme de différents matériaux ayant des anomalies de chaleur spécifique à basse température) ont été menés afin d'améliorer les performances d'un doigt froid à tube à gaz pulsé haute fréquence (30Hz) travaillant avec de l'hélium 4.Cette thèse a permis d'obtenir la meilleure performance mondiale en terme de température limite en utilisant de l'hélium 4 et avec un pré-refroidissement à 20K. Une température limite de 3,86K a été obtenue et une puissance froide de 25mW est disponible à 5K. Cette thèse a également permis d'étudier l'effet du gaz réel sur le comportement de la machine, en particulier grâce à des mesures de profils de température du régénérateur. Cinq configurations différentes de régénérateur (variation de la répartition de chaleur spécifique le long du régénérateur froid) ont été testées. Elles ont permis de mieux comprendre le rôle de la répartition de la chaleur spécifique dans le régénérateur. Ces différentes mesures ont été complétées avec des études de fluctuations de températures pariétales réalisées à l'aide d'une centrale d'acquisition rapide (toutes les millisecondes). / Some astrophysics missions embark infrared or X detectors which are cooled down to subkelvin temperatures using a cryogenic cooling system that features helium bath (like for the Herschel satellite) or a Joule-Thomson cryocooler (like for the Planck satellite) for the precooling of the subkelvin cooling stage. A pulse tube cold finger which would have the same performances as a Joule-Thomson cryocooler could offer some advantages for future cryogenic chains (no need of precooling, simplicity of integration, increased reliability).The goal of this PhD is the making and the study of a pulse tube cold finger working at temperature around 4K which could replace a Joule-Thomson cryocooler. Two main lines have been worked on simultaneously : studies on materials for the cold regenerator and studies on the cold finger performances. Technological developments on the cold regenerator (including study and shaping of different materials with specific heat anomalies at low temperature) have been performed to enhance the performances of a cold finger working at high frequency (30Hz) with helium 4.The work done during this PhD led to the best no-load temperature never achieved using helium 4 and with a precooling of 20K. A no-load temperature of 3.86K has been obtained and 25mW of cooling power are available at 5K. In addition the effect of real gas on the cryorefrigerator operation has been studied in particular thanks to the measurement of regenerator thermal profiles. Five configurations with different regenerator fillings (variation of the distribution of the specific heat along the cold regenerator) have been tested. These five tests led to a better understanding of the role of the distribution of the specific heat in the regenerator. These measurements have been completed with studies of regenerator wall temperature fluctuations recorded thanks to a fast data acquisition system (each millisecond).

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La chute chez les seniors constitue un problème de santé publique. Citée comme la seconde cause de décès accidentel dans le monde, elle concerne un tiers des Français de plus de 65 ans. Les séquelles physiques et fonctionnelles qui en résultent, les conséquences psychosociales nuisibles pour la qualité de la vie, la perte d’autonomie et son coût de prise en charge justifient l’attention qui lui est actuellement portée. Du point de vue du chercheur, les interprétations sous-jacentes à la surexposition des personnes âgées au risque de chute restent controversées, notamment parce que la compréhension de la coordination dynamique corporelle et de l’implication corticale lors du contrôle de l’équilibre est encore limitée. L’étude de la chute et des mécanismes qui y conduisent présente donc un double intérêt, fondamental et sociétal. Une chute survient si deux conditions sont réunies. La première est la perte initiale de l’équilibre, un ‘pré-requis’ qui peut toucher la population entière dans son quotidien. La seconde est un échec des mécanismes de rééquilibration, c’est à dire de la stratégie de réponse mise en œuvre pour compenser la déstabilisation : comment s’opère la sélection d’une stratégie de rattrapage, à partir de quelle appréciation du contexte et des informations sensorielles disponibles est-elle choisie ? qu’est ce qui assure son opérationnalité et garantit le rattrapage ou signe au contraire son échec ?...Pour répondre à ces questions, nous nous sommes donc intéressés à ce moment critique où il est encore possible de modifier l’issue finale par des ajustements posturaux et des actions motrices rapides et adéquats chez une population de jeunes adultes. La première étude est une analyse globale de la phase précoce d’une chute -abrégée par un harnais- (soit quelques centaines de millisecondes après la perturbation), afin d’évaluer la capacité du sujet à réagir à une perturbation imprévue et de développer des stratégies garantissant une protection efficace. Cette première étape se propose d’identifier les indicateurs discriminants et prédictifs d’une chute et d’un rattrapage au niveau neurophysiologique et biomécanique. Cette étude a également permis de mettre en évidence la présence d’un délai temporel incompressible appelé « phase passive », source de contraintes spatio-temporelles à l’expression complète d’une réponse posturale adaptée. Dans la seconde étude, de modélisation, nous avons élaboré un modèle mécanique personnalisé, construit à partir de radiographies tridimensionnelles non invasives du corps entier. Cette modélisation nous a permis d’analyser la contribution relative de propriétés biomécaniques passives et des synergies musculaires actives en jeu pendant les perturbations récupérables de l’équilibre ou non en comparant les résultats expérimentaux (‘réels’) obtenus à l’aide d’un dispositif asservi pour provoquer des chutes de plain-pied et la réponse théorique prédite (‘simulée’) à l’aide du modèle. Les résultats obtenus permettent de confirmer que le comportement du corps est en phase précoce-dicté par ses propriétés mécaniques, et peut être assimilé à un modèle simplifié. Après avoir mis en évidence l’existence d’une phase inertielle d’une durée équivalente à la moitié du temps disponible avant l’impact, notre questionnement s’est orienté vers le traitement de l’information en-cours lors de cette phase afin d’évaluer la contribution corticale alors que la réponse posturale évolue. La troisième étude consiste principalement à appréhender la charge cognitive impliquée dans le contrôle sensori-moteur, en particulier lors d’une chute, à l’aide du paradigme de double-tâche. En conclusion, à travers une approche pluridisciplinaire, les résultats obtenus dans cette thèse permettent d’émettre des recommandations intéressantes pour une prévention et une rééducation adaptée dans le but de contribuer à l’amélioration de la qualité de vie des personnes âgées. / A better understanding of what happens during an unintentional fall is relevant in preventing their occurrence. A fall is due to a failure of compensatory reactions to recover from postural perturbations during the descent phase which starts at the subject loss of balance point and lasts no more than 700-1000milliseconds [Hsiao, 1998]. The aim of the first study was to compare the biomechanical and muscular behavior during the pre-impact phase during non-recoverable falls and successful recovery trials. The experimental study aimed to evaluate the subject’s ability to distinguish in the first 500 milliseconds following the onset of perturbation a low-threatening perturbation from a high challenging one and can then predict the scenario that will more likely lead to a fall using specific motor strategies. In such a challenging task, we hypothesized that the constraints imposed by the biomechanical properties ultimately determine the ability to trigger efficient muscle activities. Full body 3D kinematics and associated muscle activities were collected in 30 young healthy subjects during fast and slow unpredictable multidirectional support-surface translations. 40 cm support-surface translations were used to evoke the balancing reactions (0,35 vs 0,9 m/s during resp. 1000 vs 500 millisecond The perturbation velocities were selected so that successful recovery should occur in milder trials whereas fast trials were sufficiently challenging to trigger non-recoverable falls. Analyses focused on the spatial and temporal characteristics of the Centre of Mass, angle variations, recovery step characteristics, and EMG activities (onset latencies and amplitudes) across each trial and muscle. Moreover, a 17-segment numerical and personalized model was created, based on stereoradiographic head to feet X-ray images followed by 3D-reconstruction methods to assess subject-specific geometry and inertial parameters. The outputs resulting from simulated falls allowed us to discard the contributions of the passive (inertia-induced) versus the active mechanisms (feedback-controlled and time-delayed neuromuscular components) of the response. The first outcome of that study was that the fall could be divided in distinct phases. For about 200 milliseconds following the onset of platform translation, the head remained stable in space. Similarly, the comparison with the simulated data supported that the CoM displacement matched the subject-dependant mechanical model. During a second phase of the fall, despite the fact that automated muscle postural synergies started at 80 milliseconds after perturbation onset, the trajectory of the body appeared to be exclusively dictated by its biomechanical properties. Later, muscle activities influenced the body trajectories, which consequently differed on a trial-to-trial basis. The simulation was in good agreement with the experimental results. The specificity of the postural response resulting in a strategy chosen to avoid a fall thus appeared in a late-phase, which can be explained because during a fall, the subjects had to prepare to the impact on the basis of sensory information that were not redundant but available in a sequential order: proprioceptive information appearing first while vestibular and visual information continued to signal a stabilized head in space. The sole proprioceptive information would be insufficient to trigger rapid and appropriate postural response. Moreover, in accordance with our results suggesting the importance of the late-phase and on-line controlled responses, a long inertial passive phase in the fast trials does not allow a large spatiotemporal window for compensatory reactions to occur. These could not only depend on the previously described automated postural synergies because the time constraints imposed by biomechanics permit in principle volitional motricity to play an important role very early in the fall. (...)