Cette thèse présente trois essais qui fournissent un aperçu global de la manière dont les chocs au niveau du marché immobilier affectent l'économie et vice versa.Dans le premier essai, nous utilisons des modèles de Markov à changement de régimes avec des probabilités qui dépendent du temps et des probabilités fixes afin d'évaluer l'ampleur des mécanismes de transmission entre le marché de placements immobiliers, le marché du logement et le marché boursier au Royaume-Uni et aux États-Unis. Nous montrons que la relation entre les marchés immobiliers et les marchés des actions est plus significative quand les marchés immobiliers sont considérés comme des variables explicatives.Dans le deuxième essai, nous introduisons le marché d'immobilier commercial afin d'identifier les interactions entre différents marchés immobiliers et certaines variables macroéconomiques. Nous utilisons une fonction de cohérence dynamique dans un cadre d'analyse spectrale pour évaluer ces liens. Les résultats montrent une tendance commune à long terme des différents marchés immobiliers. Aux États-Unis, les canaux de transmissions: richesse et dépenses de logement sont très conducteurs en cas de crise immobilière. Cependant, au Royaume-Uni, seulement le canal de la richesse s'avère conducteur dans les périodes de ralentissement du marché immobilier. Le troisième essai développe un cadre pour modéliser le marché de logement français. Nous élaborons et estimons un modèle de recherche d'équilibre du marché du logement segmenté entre locataires et propriétaires se caractérisant par une hétérogénéité des besoins de logement. Notre modèle reproduit l'évolution des prix de l'immobilier sur le marché français de 1996 à 2006, ainsi que la corrélation entre le prix, l'âge et la durée. En outre, nous montrons que l'inadéquation des individus avec leur logement est fortement corrélée avec le cycle de vie, et que l'agrégation de ces événements peut empêcher l'équilibre du marché à long terme. / This thesis contains three essays on the linkages between real estate and the wider economy. We provide a global snapshot of how shocks in the real estate market affect the economy and vice versa. In the first essay, we use Markov Switching models with time varying transition probabilities and fixed time transition probabilities in order to assess the magnitude of the transmission mechanisms between real estate markets and stock markets in the UK and the US. The results show a more significant credit price effect than a wealth effect. In addition, the different features of the linkages between real estate markets and stock markets are explained by the difference in the indices constructions of the housing prices and the REIT models in the two countries.In the second essay, an additional property market is included to further investigate the links of different real estate markets with some key macroeconomic variables. We use a dynamic coherence function in a spectral framework to assess these linkages. We find a common trend that drives all the real estate markets, particularly in the long run. The results show that in the US, wealth and housing expenditure channels are very conductive during real estate crises. However, for the UK, only the wealth is significant as a transmission channel during real estate market downturns. The third essay develops a framework that models the French housing market. We specify and estimate an equilibrium search model of the housing market that features a segmented housing market with heterogeneity in housing need. Our model reproduces almost exactly the evolution of French housing prices from 1996 to 2006, along with the correlation between price, age and duration. In addition we show that individuals mismatch is highly correlated with the life-cycle, and that aggregation of such events can prevent the market from clearing over a long period of time.

Title: Spectral Analysis of Electromyography Data of Power Lifters Objectives: The aim of this thesis is a description of muscle activity and its measu- rement using electromyography (EMG), description of parameters of EMG signal and their relationship to neuromuscular physiology. The aim of the practical part is an implementation of spectral analysis of EMG data of power lifters when performing 4 series of 5 split-squats carrying loading in one hand. Methods: The spectral analysis of EMG data of 35 athletes is presented. The athletes performed 4 series of 5 split-squats with one sided loading. The loading was 25% and 50% of their body mass and the carrying position was homolateral and contralateral to stance leg. Muscles chosen for measurement were vastus medialis obliquus, vastus lateralis obliquus, gluteus medius and biceps femoris of both sides. The implementation of digital signal proces- sing algorithm was done using Matlab and its Signal Processing Toolbox. The spectral analysis was implemented using discrete Fourier transform with sliding 256-sample window size and 32-sample window increment. The resulting spectrogram was divided into parts based on smoothed EMG. Median frequency for each split-squat was calculated. For the statistical processing we used median frequency differencies...

Le présent travail de thèse porte sur la modélisation et la simulation, en domaine temporel, de l'interaction entre un faisceau d'électrons et une onde hyperfréquence dans la structure à onde lente d'un TOP à hélice. Puisque le TOP est un instrument surdimensionné, les modèles non-stationnaires généraux utilisés dans les codes commerciaux nécessitent de trop grosses ressources de calcul pour pouvoir être utilisés en un temps raisonnable dans un but de conception. Il est donc nécessaire de faire appel à des modèles spécialisés. Durant cette thèse, nous nous sommes intéressés au "modèle discret non-stationnaire d'excitation d'un guide d'onde Périodique" de S. Kuznetsov. En 2007, N. Ryskin et al. avaient prouvé que ce modèle pouvait convenablement s'appliquer aux TOP à cavités couplées dans le cadre d'une application à une dimension du modèle. Lors de cette thèse, nous avons démontré, via le développement d'un code à une dimension (HelL-1D), que le modèle discret s'applique convenablement aux TOP à hélice. L'implémentation de ce modèle, dans un code à deux dimensions (HelL-2D) a, elle aussi, été effectuée. Enfin, nous avons développé une méthode permettant de contrôler de manière quantitative, dans le modèle discret, les phénomènes de réflexions aux extrémités de la ligne à retard, qui peuvent jouer un rôle important dans la stabilité de l'instrument. / This Ph.D. work deals with the time domain modeling and simulation of the electron beam/wave interaction in the slow-wave structure of a helix traveling-wave tube. Since a TWT is a device of which the geometry is oversized then the commercial software based on non-stationary general models needs so much computational resources that it cannot be used for design activities. During this Ph.D., we focused on the so called Kuznetsov's "discrete model of excitation of a periodic waveguide" which is a specialized model of beam/wave interaction in TWT. By 2007, N. Ryskin et al., showed that this model could conveniently apply to TWT with coupled cavities structure in one dimension. During this thesis, we first demonstrated that the discrete model could also apply to helix TWT with a sufficient (1%) accuracy via the development of a one-dimensional software called HelL-1D. We also implemented the discrete model for helix TWT in two dimensions (HelL-2D code). Finally, we developed a method, which is an extension of the discrete model, and which permits to take into account quantitatively the reflection phenomena at the terminations of a slow-wave structure in this model. This last study was very important since the stability of TWT strongly depends on this parameter.

L’objectif de cette thèse a été d’analyser l’effet de l’exercice physique réalisé sur plateforme vibrante (whole-body vibration, WBV) sur l’activité musculaire des membres inférieurs, de développer des outils d’analyse méthodologiques et de proposer des recommandations pratiques d’utilisation. Deux études méthodologiques ont été menées pour identifier la méthode optimale permettant de traiter les signaux d'électromyographie de surface (sEMG) recueillis pendant la vibration et d'analyser l'influence de la méthode de normalisation de l'activité sEMG. Une troisième étude visait à mieux comprendre si les pics sEMG observés dans le spectre de puissance du signal contiennent des artéfacts de mouvement et/ou de l'activité musculaire réflexe. Les trois études suivantes avaient pour but de quantifier l’effet de la WBV sur l’activité musculaire en fonction de différents paramètres tels que, la fréquence de vibration, l'amplitude de la plateforme, une charge supplémentaire, le type de plateforme, l'angle articulaire du genou, et la condition physique du sujet. En outre, l'objectif a été de déterminer l'accélération verticale minimale permettant de stimuler au mieux l'activité musculaire des membres inférieurs. En résumé, les recherches menées au cours de cette thèse fournissent des solutions pour de futures études sur : i) comment supprimer les pics dans le spectre du signal sEMG et, ii) comment normaliser l'activité musculaire pendant un exercice WBV. Enfin, les résultats de cette thèse apportent à la littérature scientifique de nouvelles recommandations pratiques liées à l’utilisation des plateformes vibrantes à des fins d’exercice physique. / The aim of this thesis was to analyze the effect of whole-body vibration (WBV) exercise on lower limb muscle activity and to give methodological implications and practical applications. Two methodological studies were conducted that served to evaluate the optimal method to process the surface electromyography (sEMG) signals during WBV exercise and to analyze the influence of the normalization method on the sEMG activity. A third study aimed to gain insight whether the isolated spikes in the sEMG spectrum contain motion artifacts and/or reflex activity. The subsequent three investigations aimed to explore how the muscle activity is affected by WBV exercise, with a particular focus on the vibration frequency, platform amplitude, additional loading, platform type, knee flexion angle, and the fitness status of the WBV user. The final goal was to evaluate the minimal required vertical acceleration to stimulate the muscle activity of the lower limbs. In summary, the research conducted for this thesis provides implication for future investigations on how to delete the excessive spikes in the sEMG spectrum and how to normalize the sEMG during WBV. The outcomes of this thesis add to the current literature in providing practical applications for exercising on a WBV platform.

A obesidade, a resistência à insulina (RI), o diabetes e a hipertensão arterial (HA) estão associadas à maior morbidade e mortalidade cardiovascular. Os verdadeiros mecanismos relacionados com a RI bem como as associações metabólicas e alterações hemodinâmicas a essa condição não estão bem estabelecidos. Sabe-se que o aumento dos ácidos graxos livres (AGL) pode estar relacionado inclusive com as alterações hemodinâmicas como o aumento na pressão arterial (PA), na freqüência cardíaca (FC) e na redução da distensibilidade de pequenas artérias (piora da função endotelial). A infusão de Intralipidâ e heparina (ILH) é hoje um modelo de hiperlipidemia, que permite o aumento agudo de AGL na circulação sangüínea. O aumento da atividade do sistema nervoso simpático (SNS) tem sido apontado como possível mecanismo para parte das alterações hemodinâmicas decorrentes da hiperlipidemia aguda. O objetivo deste estudo foi avaliar o impacto da injeção de insulina in bolus e da infusão de ILH na resposta hemodinâmica, metabólica e autonômica em pacientes portadores da doença de Chagas. Para tanto, foram utilizados12 pacientes portadores da doença de Chagas sem insuficiência cardíaca (grupo Ch) e 12 voluntários normais (grupo C), pareados para idade, sexo, raça, PA e FC. Os mesmos foram avaliados em condições basais e submetidos aos testes de tolerância à insulina (TTI) e de infusão de ILH. Durante o TTI foram realizadas medidas na PA, na FC e dosagens de glicemia, insulina e noradrenalina. No dia da infusão de ILH os registros da PA e da FC foram realizados batimento a batimento (Finometer®), colhido sangue para dosagens bioquímicas (glicose, insulina, noradrenalina) e realizado análise espectral em todos os participantes. Em condições basais, os níveis de noradrenalina eram superiores no grupo Ch, quando comparados com o grupo C. Após o TTI, houve queda significativa na glicose plasmática em ambos os grupos. A PA e a FC não se modificaram durante TTI no grupo Ch, e aumentaram significativamente no grupo C. Houve aumento dos níveis de noradrenalina plasmática no grupo C e discreta queda no grupo Ch. Em relação à de ILH, ela resultou em aumento na PA nos dois grupos. A FC aumentou no grupo Ch e não se modificou no grupo C. O componente de baixa freqüência (LF) era maior no grupo Ch em condições basais e aumentou em ambos os grupos durante a infusão de ILH. O componente de alta freqüência (HF) diminuiu nos dois grupos de maneira significativa, sendo menor no grupo Ch mesmo em condições basais. Não houve modificação significativa nos valores de noradrenalina plasmática no grupo Ch durante a infusão de ILH, a qual aumentou significativamente no grupo C. Esses dados mostram: Maior resposta da atividade simpática no grupo C durante o TTI pelo aumento da PA, da FC, dos valores de noradrenalina plasmática e a sensibilidade à insulina foi semelhante nos dois grupos, uma vez que a queda da glicose após o estímulo com bolus de insulina foi significante nos dois grupos. Aumento significativo da PA e da atividade simpática (avaliada pela análise espectral) nos dois grupos durante a infusão de ILH. Diminuição da atividade do componente de HF (parassimpático) nos dois grupos após a infusão de ILH. O comprometimento significativo da sensibilidade baroreflexa no grupo Ch após a infusão de ILH. Em conclusão, pacientes chagásicos têm maior concentração de noradrenalina em condição basal em relação ao grupo controle, porém a resposta na PA e na FC durante o TTI no grupo Ch foi menor, sugerindo disautonomia. A infusão de ILH resultou no aumento da PA em ambos os grupos e menor queda da FC no grupo Ch, sugerindo comprometimento do baroreflexo. / The obesity, insulin resistance (IR), diabetes and hypertension (HA) are associated with increased cardiovascular morbidity and mortality. The real mechanisms related to the RI and the associations of metabolic and hemodynamic changes to this condition are not well established. It is known that the increase in free fatty acids (FFA) may also be related to the hemodynamic changes as the increase in blood pressure (BP), heart rate (HR) and reducing the distensibility of small arteries (worsening of endothelial function). The infusion of Intralipid® and heparin (ILH) is today a model of acute hyperlipidemia, which allows the acute increase of FFA in the blood circulation. Increase in the nervous sympathetic activity system (SNS) has been suggested as a possible mechanism for part of hemodynamic changes resulting from acute hyperlipidemia. The purpose of this study was to evaluate the impact of the injection of bolus of insulin and the infusion of ILH in hemodynamic, metabolic, and autonomic response in patients with Chagas\' disease. Twelve patients with Chagas\' disease without heart failure (Ch group) and 12 normal volunteers (C group), matched for age, sex, race, BP, and HR were selected for this study. They were evaluated at baseline conditions and subjected to insulin tolerance test (ITT) and also ILH infusion. During the ITT measures of BP, HR, and biochemistry dosages as blood glucose, insulin and norepinephrine were taken. During the infusion of ILH the records of the BP and HR beat-to-beat (Finometer®) were done, blood samples were collected for biochemical dosages (glucose, insulin, noradrenalin) and spectral analysis was also conducted in all participants. In baseline conditions, norepinephrine levels were higher in the Ch group, compared with the C group. After ITT, there was significant fall in plasma glucose in both groups. The BP and HR did not change during the ITT in Ch group, and increased significantly in C group. There was an increase in plasma levels of norepinephrine in group C and slight fall in group Ch. The ILH infusion resulted in an increase in the BP in both groups. The HR increased in the Ch group and did not change in C Group. The component of low frequency (LF) was higher in group Ch in the baseline conditions and it increased in both groups during the ILH infusion. The component of high frequency (HF) decreased in both groups, and it was lower even in the Ch group even at baseline conditions. There was no significant change in the values of plasma norepinephrine in the group Ch during the ILH infusion, and it increased significantly in C group. These data show: Similar insulin response in both groups, according to the glucose drop. Higher increase in BP and HR in C Group in comparison to Ch group and higher increase in plasma norepinephrine in C group comparing to Cg group. Significant increase in BP and sympathetic activity (evaluated by spectral analysis) in both groups during the ILH infusion. Decrease in the HF component (parasympatethic activity) in both groups after ILH infusion. A significant baroreflex sensitivity impairment in the Ch group after the ILH infusion. In conclusion, chagasic patients have greater concentration of norepinephrine in baseline condition comparing to C group, but the response of BP and HR during the ITT in Ch group was lower, suggesting dysautonomia. The ILH infusion resulted in an increase on BP in both groups and also increased the HR in Ch group, suggesting baroreflex impairment.

Variações climáticas podem resultar na entrada insuficiente de água no balanço hídrico de uma região, acarretando em inconsistências relacionadas à outorga de água superficial. O sistema de outorga de água superficial utiliza as vazões percentis (Q7,10, Q90, Q95) para definir a vazão máxima outorgável. No entanto, em períodos de estiagem tais vazões de referência podem não ser suficientes para atender a demanda outorgada, demandando a captação de águas subterrâneas para contrabalançar essa insuficiência hídrica do manancial superficial. Portanto, a outorga dos recursos hídricos deve ocorrer de forma integrada e sustentável, considerando a alteração da descarga do aquífero para o rio devido à captação subterrânea. O objetivo deste trabalho é estimar a disponibilidade hídrica integrada (superficial e subterrânea), por meio de um modelo empírico linear, proposto como função da média móvel da precipitação de períodos anteriores relacionados ao tempo de regulação do aquífero. Técnicas de correlação e espectrais foram empregadas na análise de séries temporais de precipitação (P) e vazão (Q) da bacia hidrográfica do Ribeirão da Onça, com o objetivo de determinar os tempos de resposta de Q em relação a P. A metodologia proposta foi verificada para precipitação e vazões observadas na bacia com área de 65 km2 no período de 2003 a 2014. Os resultados indicam que o aquífero armazena uma parcela de água precipitada e controla o fluxo para o rio, com tempos de regulação de aproximadamente 60 dias para o escoamento subsuperficial e de aproximadamente 2 anos para o escoamento de base. A metodologia também foi testada para duas sub-bacias hidrográficas do Rio Jacaré-Guaçu, com áreas de 1867 e 3519 km2. A adoção da metodologia proposta permite calcular uma vazão de referência sustentável, possibilitando prever a variação da vazão de base nos períodos de recessão, por estar definida em função de precipitações passadas. Portanto, tal vazão seria mais condizente com as observadas no meio ambiente, proporcionando um adequado funcionamento do ecossistema, garantindo assim a sua preservação. / Climatic variation may result in insufficient input of water in the water balance in a region, resulting in inconsistencies in the water rights permits. Brazilian water allocation system uses the flow duration curves (Q7,10, Q90, Q95) to establish the maximum allowable discharge. However, during droughts such reference discharges may not reach the water rights permits, requiring groundwater extraction to compensate this deficiency in surface water bodies. Hence, the water right permits must be integral, considering the base flow variation due to the groundwater extraction. The aim of this study is to determine the integrated water availability (surface and groundwater), using an empirical linear model, proposed as a function of the average rainfall of previous periods related to the aquifer regulation time. Correlation and spectral techniques were employed for time-series analysis of precipitation (P) and discharge (Q) in the Ribeirão da Onça watershed, to determine response times of Q as a function of P. The proposed methodology was developed for precipitation and discharge observed from 2003 to 2014 in a watershed with an area of 65 km2. The obtained results indicate that the aquifer stores the rainfall water with regulation times of approximately 60 days for the subsurface flow, ans approximately 2 years for the base flow. The methodology was also tested for two sub-basins of the Jacaré-Guaçú River watershed, with areas of 1867 and 3519 km2.The proposed methodology allows the estimation of a sustainable reference discharge making it possible to predict the base flow variation during recession periods, since it is defined as a function of past rainfall. Therefore, this discharge is more consistent with the values observed in the environment, allowing a proper functioning of the ecosystem, thereby ensuring their preservation.

Series temporais de correntes, vento (força e direção), temperatura e salinidade, com duração de 24h, obtidas em 5 estações na Baia da Ilha Grande (rj), de 3-29/01/82, foram analisadas. As medições de corrente foram feitas a5, 12 e 20m, a cada 5min e a 2m acima do fundo, a cada 12min; temperatura e salinidade em cinco profundidades a cada 3h e vento a cada 1h. Foram utilizadas análises de series temporais através dos métodos diretos (periodograma) e indireto para as estimativas espectrais alisadas, bem como as equações hidrodinâmicas na determinação dos períodos. Foram utilizados os testes: ruído branco e fisher-whittle, a análise dos espectros rotatórios e a análise cruzada entre vento e corrente, ao longo de três camadas: superfície intermediaria e de fundo. Foram determinadas oscilações de 4,8h e identificadas como seiches internos e detectadas oscilações com período de 3,4h associadas à ressonância com o vento. Em todo o sistema da baia o período de 6h mostrou-se significativo, correspondendo à oscilação natural da baia. Foram detectadas oscilações de alta freqüência 11 e 20min, 20cm/s eventualmente associadas a vórtices e meandros da corrente. Água subtropical na camada de fundo da baia / Temporal series of currents, wind, water temperature and salinity, obtained from 5 oceanographic stations located in and around Ilha Grande Bay (RJ, Brazil), from January 23 to 29, 1982, were analyzed. AlI series have 24 hours. Currents measu¬rements were dione at depths of 5, 12, 20 m (every 5 minutes) and near the bottom (every 12 minutes). Temperature and salinity data were taken from 5 depths every 3 hours for each, while the wind was measured every hour. The present work was per¬formed in order to investigate short-period oscillations present in the region, related to density stratification and to the features of the basin, as well as to describe the circulation patterns and currents variations during one day interval. Two kinds of analysis were used: temporal series analysis, using statistical and spectral methods, and calculations by hydrodynamic motion equations. In temporal series analysis the direct (periodogram) and indirect methods were used for the spectral estimations. White-noise, Fisher- Whittle tests and rotational spectra analysis were also applied, besides the cross spectrum analysis for the data about winds and currents. The results indicate an intense and unidirectional circulation in the layer above 5 meters, from the western to the eastern portion of the Bay, through Central Channel. In this layer, on the eastern sea-opening side, a flux toward the Bay was observed. These motions, within 5 meters depth, were attributed to a circulation generated by a horizontal density difference between oceanic and inshore waters, with few contribution from tides and winds. At intermediate and near bottom layers, a horizontal homogeneity was observed and, consequent1y, smaller horizontal density gradients were detected. This way, circulation caused by tides was stronger than the movements forced by su¬perficial layers. Resultant bottom currents, observed at the Bay openings, led to the open-sea. At Central Channel, 4.8 h period oscillations were detected, and identified as internal seiches. In the eastern Portion, 3.4 hour period oscillations were detected, related to wind resonance. In alI the bay-system, the 6.0 hour period was significant, corresponding to the bay\'s natural oscillation. The study area presented a density stratification in two layers, with a single water type filling alI the portion below the 20 meters. This water, with characteristics of Subtropical Water, occupied the bottom layer due to an upwelling process produced by the dynamics of currents and winds in the continental shelf . In the two stations located off the bay, the wind and currents observations support this upwelling hypothesis.

Récemment, le diagnostic des machines tournantes devient un des sujets de recherche les plus importants. Plusieurs axes sont développés dans ce domaine : traitement de signal, reconnaissance des formes et autres. En plus, les systèmes industriels peuvent être surveillés à distance en temps réel grâce à la disponibilité de l’internet. Cette surveillance se trouve exigeante au niveau de l’acquisition et le stockage des données. En 2004, le Compressive Sensing est introduit dans le but d’acquérir les données a une basse fréquence afin d’économiser l’énergie dans les réseaux de capteurs sans fils. Des résultats similaires peuvent être achevés par l’Echantillonnage Aléatoire qui procure une acquisition à basse fréquence grâce à sa propriété d’anti-repliement. Comme cette technique d’échantillonnage est jusqu’à l’instant de la rédaction de cette thèse n’est pas encore disponible au marché, le travail sur ce sujet se trouve promettant afin de présenter une implémentation pratique validée. D’où, la contribution de cette thèse est de présenter les différentes propriétés de l’échantillonnage aléatoire à travers une étude théorique détaillée dans le domaine temporel et fréquentiel suivie d’une simulation et d’une application pratique sur des signaux synthétisés simples puis sur des signaux de vibration extraits des principaux composants des machines : roulements et engrenages. Les résultats obtenus au niveau de la simulation et la pratique sont satisfaisants grâce à la diminution de la fréquence d’échantillonnage et la quantité de données à sauvegarder ce qui peut être considéré comme une résolution de la problématique de la surveillance à temps réel / Nowadays, machine monitoring and supervision became one of the most important domains of research. Many axes of exploration are involved in this domain: signal processing, machine learning and several others. Besides, industrial systems can now be remotely monitored because of the internet availability. In fact, as many other systems, machines can now be connected to any network by a specified address due to the Internet of Things (IOT) concept. However, this combination is challenging in data acquisition and storage. In 2004, the compressive sensing was introduced to provide data with low rate in order to save energy consumption within wireless sensor networks. This aspect can also be achieved using random sampling (RS). This approach is found to be advantageous in acquiring data randomly with low frequency (much lower than Nyquist rate) while guaranteeing an aliasing-free spectrum. However, this method of sampling is still not available by hardware means in markets. Thus, a comprehensive review on its concept, its impact on sampled signal and its implementation in hardware is conducted. In this thesis, a study of RS and its different modes is presented with their conditions and limitations in time domain. A detailed examination of the RS’s spectral analysis is then explained. From there, the RS features are concluded. Also, recommendations regarding the choice of the adequate mode with the convenient parameters are proposed. In addition, some spectral analysis techniques are proposed for RS signals in order to provide an enhanced spectral representation. In order to validate the properties of such sampling, simulations and practical studies are shown. The research is then concluded with an application on vibration signals acquired from bearing and gear. The obtained results are satisfying, which proves that RS is quite promising and can be taken as a solution for reducing sampling frequencies and decreasing the amount of stored data. As a conclusion, the RS is an advantageous sampling process due to its anti-aliasing property. Further studies can be done in the scope of reducing its added noise that was proven to be cyclostationary of order 1 or 2 according to the chosen parameters

Schwankungen des arteriellen Blutdrucks (BP) im niederfrequenten Bereich (LF, 0.02-0.2 Hz) sind möglicherweise Ausdruck von endokrinen Regulationssystemen bei der Aufrechterhaltung der kardiovaskulären Homöostase, wie beispielsweise des Renin-Angiotensin-Systems (RAS). Bei Untersuchungen an Ratten mit sogenannter "one-clip, two-kidney" (1C-2K) Goldblatt Hypertonie wurde ein Anstieg der LF Komponente des BP-Powerspektrums unter aktiviertem RAS gefunden. Trotz der bisherigen Untersuchungen blieb jedoch die Frage ungeklärt, ob dieser Anstieg LF(BP)-Power auf einer Stimulation des RAS beruht, oder durch die Blutdruckerhöhung selbst bedingt ist. Aus diesem Grund wurden die Auswirkungen eines stimulierten RAS auf BP-Oszillationen im LF-Bereich in dieser Studie untersucht, während ein Blutdruckanstieg pharmakologisch verhindert wurde. Zweiundzwanzig normotensive Wistar- und siebzehn normotensive Brown-Norway-Katholiek-Ratten wurden aus diesem Grunde chronisch mit einem Telemetriesender instrumentiert. Es erfolgten Blutentnahmen zur Reninaktivitsbestimmung, der BP wurde jeden zweiten Tag telemetrisch aufgezeichnet. Nach drei Wochen wurden die Tiere in zwei Behandlungsgruppen aufgeteilt. Entweder wurden die Tiere einer Behandlung mit Placebo zugewiesen (n=14 bei den Wistar-Ratten und n=8 bei den Brown-Norway-Katholiek-Ratten), oder sie erhielten eine Behandlung mit Hydralazin (n=8 bei den Wistar-Ratten und n=9 bei den Brown-Norway-Katholiek-Ratten, 40-120 mg/kg/Tag). Ein Silberclip (innerer Durchmesser 200 Mikrometer) wurde auf die linke Nierenarterie plaziert, eine erneute Blutentnahme erfolgte und der BP wurde für weitere drei Wochen gemessen. Hiernach wurde die Behandlung beendet, der Clip von der Nierenarterie entfernt und eine letzte Blutabnahme erfolgte. Abschließende Blutdruck-Registrierungen wurden über einen Zeitraum von drei Wochen durchgeführt. Die Power im LF-Bereich wurde aus den aufgezeichneten Blutdrucksignalen berechnet. Nach Implantation eines Nierenclips stieg der BP bei den mit Placebo behandelten Tieren signifikant an (+37 +/- 5.7 mmHg bei den Wistar-Ratten und +50 +/- 7.4 mmHg bei den Brown-Norway-Katholiek-Ratten, p / Low frequency (LF, 0.02-0.2 Hz) blood pressure (BP) fluctuations may result from cardiovascular regulation by endocrine systems such as the renin-angiotensin system (RAS). Studies employing one-clip, two-kidney (1C-2K) Goldblatt hypertension in rats demonstrated an increase in the LF component of the BP power spectrum. However it remains controversial, whether this increase in LF(BP)-Power is due to the stimulation of the RAS or to the elevation in BP itself. Therefore, we investigated the effect of RAS stimulation on LF(BP) fluctuation while the increase in BP was prevented pharmacologically. Twenty-two normotensive Wistar and seventeen Brown-Norway Katholiek rats were chronically instrumented with telemetric BP sensors, blood samples for measurement of the renin activity were taken and BP was monitored every other day. Three weeks later, rats were subjected to oral treatment with either placebo (n=14 in the Wistar rats and n=8 in the Brown-Norway Katholiek rats) or hydralazine (n=8 in the Wistar rats and n=9 in the Brown-Norway Katholiek rats, 40-120 mg/kg/day). A stainless steel clip (inner diameter 200 micrometer) was placed on the left renal artery, again blood samples were taken and BP was recorded for another three weeks. Finally, treatment was discontinued, the clip was removed from the renal artery, a last blood sample was taken and BP was monitored for a final period of three weeks. LF spectral power was calculated off-line from the recorded BP signal. After renal artery clipping BP significantly increased in placebo-treated rats (+37 +/- 5.7 mmHg in the Wistar rats, +50 +/- 7.4 mmHg in the Brown-Norway Katholiek rats, p

Anbaubegleitende spektral-optische Analysen direkt an der Pflanze haben zunehmend Bedeutung für die gartenbauliche Produktion. Veränderungen individueller Pflanzeninhaltsstoffe können mit Hilfe optischer Sensoren unmittelbar und beliebig oft erfasst werden, wodurch Pflanzenreaktionen auf veränderte Umgebungs- und Kulturbedingungen instrumentell messbar sind. Im Konzept eines Präzisionsgartenbau könnten diese zusätzlichen Informationen adaptiven Kulturmaßnahmen dienen und zur effizienten Nutzung von Ressourcen in der Produktion von Obst und Gemüse beitragen. Die wellenlängenspezifische Lichtabsorption pflanzlicher Gewebe ermöglicht zerstörungsfreie Reflexions- oder Transmissionsmessungen und die Adressierung von Pigmentgruppen im ultravioletten und sichtbaren Bereich des elektromagnetischen Spektrums. Auf Grund veränderlicher Gehalte während des Wachstum und der Entwicklung pflanzlicher Gewebe, sind Pigmente zudem wichtige Indikatoren für den physiologischen Zustand von Obst und Gemüse. Präzise zerstörungsfreie Spektralanalysen werden allerdings durch komplexe optische Eigenschaften biologischen Materials, besonders im Hinblick auf die Reifeentwicklung von Obst und Gemüse erschwert. Zur Lösung dieser Problematik wurde ein neuer iterativer Ansatz (iMLR) entwickelt, der überlagerte in-situ und in-vivo Spektren individueller Pigmente aus einem Summenmessspektrum separiert. Dieser Algorithmus wurde in eine eigenständige Applikation überführt. Eine Datenbank enthält spektrale Signaturen von Chlorophyll a und b, Lycopin, β-Carotin, α-Carotin, Lutein und Violaxanthin. Obwohl die spektrale Analyse einzelner Pigmente durch optische Störgrößen in komplex aufgebauten biologischen Geweben und Pigmentgemischen erschwert ist, konnte ein neuer Ansatz erarbeitet und validiert werden. Diese Methode minimiert spektrale Überlagerung von in-situ und in-vivo aufgezeichneten Messsummensignalen und analysiert Pigmentgehalte in Farbstoffgemische zuverlässig. / Spectral measurements on plants have already been introduced in practice through extensive research and through the recent increase in the availability of low-cost devices. It can be expected that optical sensor systems may contribute to an economic and sustainable use of natural resources as a part of the concept for precision horticulture. In terms of phytomonitoring approaches, such technologies which address variable amounts of individual chromophoric plant components become more important. Their wavelength-selective light absorption makes pigments specifically responsive to reflection or transmission recordings in the ultraviolet and visible range of the electromagnetic spectrum. Additionally, pigments serve as indicators for physiological stages of leaf and fruit. Consequently, the instrumental recording of variable pigment contents has high potential with regards to dynamic plant-adapted processes during the production of fruit and vegetables. Solving the known issues of non-destructive spectroscopy, a new approach was figured out in the present work to obtain a more precise analysis of individual pigment contents, which vary during the cultivation of horticultural crops. The tool is based on an iterative algorithm (iMLR), that separates coinciding in-situ and in-vitro spectra from sum signals of individual pigments. Finally, the algorithm was integrated into a stand-alone application containing a library of chlorophyll a and b, as well as signatures of lycopene, β-carotene, α-carotene, lutein and violaxanthin. It can be pointed out that individual pigment compositions are suitable indicators of the physiological stage of horticultural products. However, the spectral analysis of single pigment levels is challenging due to complex interactions of coinciding absorption and diffuse light scattering in natural pigment mixtures or in fruit extracts. From this, an improved method for the reliable decomposition of spectral signals was developed.