Acidentes com peixes peçonhentos são muito freqüentes na região costeira do Brasil. Os bagres marinhos são os peixes peçonhentos que causam o maior número de acidentes no Brasil, especialmente no litoral sudeste, onde o bagre amarelo Cathorops spixii (Ariidae) é o mais abundante. O acidente é caracterizados por lesão dolorosa, edema intenso e ocasionalmente alguns sintomas sistêmicos. Embora estes sejam muito comuns, apenas nesta década, iniciaram-se os estudos sobre as ações dos venenos. Sendo assim, este trabalho objetivou caracterizar as principais atividades tóxicas (edema, nocicepção, hemorragia, necrose, proteólise, alterações na permeabilidade vascular e na microcirculação) induzidas pelos venenos do muco e do ferrão de C. spixii em modelo murino (Swiss, 20-22g); bem como caracterizar algumas de suas propriedades bioquímicas. Os venenos do muco e do ferrão e a mistura (muco+ferrão) foram testados. Nos ensaios de nocicepção e edema, os venenos(3; 10; 30 ou 60μg / 30μl PBS estéril) foram injetados na pata dos camundongos; para os testes de hemorragia e necrose, 50; 150 ou 300μg / 50μl PBS estéril foram injetados no dorso dos camundongos. Para a proteólise utilizou-se 3; 10; 30 ou 60μg sobre um substrato de caseína. Para a permeabilidade vascular, 10; 30 ou 60μg foram injetados via i.p. Enquanto que as alterações na microcirculação utilizouse 30μg. Ambos os venenos induziram nocicepção a partir de 3μg. Edema foi considerado significativo quando acima de 30% do controle. Todas as doses, para ambos os venenos foram capaz de induzi-lo, com pico após 2h da injeção e permanecendo por até 24h. Hemorragia e necrose não foram induzidas, mesmo após a injeção de altas doses. A permeabilidade vascular foi observada após 2h com todas as doses e venenos testados. As alterações na microcirculação foram observadas para ambos os venenos. Com 30μg observou-se o aumento do rolling de leucócitos (após10 min), extase sanguínea (após 30min, apenas no caso do muco) e contração miofibrilar (após40min). SDS-PAGE (12%) mostrou um perfil eletroforético bastante complexo, com proteínas majoritárias, acima de 97 kDa, com aproximadamente 97 kDa, entre 45 e 60 kDa e entre 20 e 30 kDa, no caso do veneno do muco. E na faixa dos 33 e acima dos 66 kDa no caso do veneno do ferrão. Diferenças são observadas entre as condições redutora e não redutora principalmente nos grupos acima de 97 kDa. A cromatografia em gel filtração não foi eficiente em separar os componentes protéicos de ambos os venenos, porém, evidencia diferenças entre os perfis. O veneno do muco contém proteínas com PI próximo a 5,0. E o ferrão deve ser composto de proteínas primordialmente aniônicas. Estes resultados mostram as importantes ações tóxicas induzidas pelos venenos do bagre marinho C. spixii, além de aspectos bioquímicos, que podem ser úteis no acompanhamento da evolução clínica e tratamento dos acidentados. / Accidents with venomous fishes are very frequent in costal waters of Brazil. Marine catfishes are the venomous fishes that cause the greatest number of accidents in Brazil, specially in southeast littoral, where the yellow-catfish Cathorops spixii (Ariidae) is the most abundant. The accidente is characterized for painful injury, intense edema and some eventul systemic symptoms; ande even these accidents are very commom,only in this decade, studies about its venoms had started. So this work intend to caracterize the main toxic activities (edema, nociception, hemorrhage, necrosis, proteolysis, alterations is vascular permeability and in microcirculation) induced by mucus and sting venom of C. spixii inmurine model (Swiss, 20-22g); besides it\'s biochemical characterization. Mucus, sting and mixture (mucus+sting) venoms were tested. In nociceptive and edematogenic assays venoms (3; 10; 30 or 60μg / 30μl sterile PBS) were injected in mice paw, whereas in hemorrhagic and necrosis assays, venoms (50; 150 or 300μg / 50μl sterile PBS) were injected in mice back. To proteolytic assay, 10; 30 or 60μg were utilized over a casein substrate. To vascular permeability assay 10; 30 or 60μg were injected by i.p. way. Whereas on microcirculation alterations 30μg were aplied over exposed cremaster muscle. All venoms induced nociception with 3 μg or more. Edema was considered significant when over 30% of control group and was induced by all venoms, too, with bottom after 2h, and continuing until 24h. Hemorrhage and necrosis weren\'t observed even so high doses were injected. Alterations on micocirculation were observed for bath venoms. 30μg increased leukocyte rolling (after 10min), blod flow stopped (after 30min, but only with mucus venom), and caused contraction on miofibres (after 40min). SDS-PAGE (12%) showed a complex pattern with several bands allover the gel. Skin and Sting venoms share some identical bands but there are important differences. Mucus venom majority bands are found between 20-30 kDa, 45-60 kDa and over 97 kDa. Sting venom major ones are between 33 kDa and 55-60 kDa. Gel- Filtration (Sephadex) showed 4 (Mucus venom) and 5 peaks (Sting venom). In this differential peak, there are molecules with high molecular weight. These results show that both venoms are able to induce important toxic activities induced by mucus and sting venoms of C. spixii. Besides, biochemical aspects that can be usefull to understand envenonming and propose better treatment.

Acidentes com peixes peçonhentos são muito freqüentes na região costeira do Brasil. Os bagres marinhos são os peixes peçonhentos que causam o maior número de acidentes no Brasil, especialmente no litoral sudeste, onde o bagre amarelo Cathorops spixii (Ariidae) é o mais abundante. O acidente é caracterizados por lesão dolorosa, edema intenso e ocasionalmente alguns sintomas sistêmicos. Embora estes sejam muito comuns, apenas nesta década, iniciaram-se os estudos sobre as ações dos venenos. Sendo assim, este trabalho objetivou caracterizar as principais atividades tóxicas (edema, nocicepção, hemorragia, necrose, proteólise, alterações na permeabilidade vascular e na microcirculação) induzidas pelos venenos do muco e do ferrão de C. spixii em modelo murino (Swiss, 20-22g); bem como caracterizar algumas de suas propriedades bioquímicas. Os venenos do muco e do ferrão e a mistura (muco+ferrão) foram testados. Nos ensaios de nocicepção e edema, os venenos(3; 10; 30 ou 60μg / 30μl PBS estéril) foram injetados na pata dos camundongos; para os testes de hemorragia e necrose, 50; 150 ou 300μg / 50μl PBS estéril foram injetados no dorso dos camundongos. Para a proteólise utilizou-se 3; 10; 30 ou 60μg sobre um substrato de caseína. Para a permeabilidade vascular, 10; 30 ou 60μg foram injetados via i.p. Enquanto que as alterações na microcirculação utilizouse 30μg. Ambos os venenos induziram nocicepção a partir de 3μg. Edema foi considerado significativo quando acima de 30% do controle. Todas as doses, para ambos os venenos foram capaz de induzi-lo, com pico após 2h da injeção e permanecendo por até 24h. Hemorragia e necrose não foram induzidas, mesmo após a injeção de altas doses. A permeabilidade vascular foi observada após 2h com todas as doses e venenos testados. As alterações na microcirculação foram observadas para ambos os venenos. Com 30μg observou-se o aumento do rolling de leucócitos (após10 min), extase sanguínea (após 30min, apenas no caso do muco) e contração miofibrilar (após40min). SDS-PAGE (12%) mostrou um perfil eletroforético bastante complexo, com proteínas majoritárias, acima de 97 kDa, com aproximadamente 97 kDa, entre 45 e 60 kDa e entre 20 e 30 kDa, no caso do veneno do muco. E na faixa dos 33 e acima dos 66 kDa no caso do veneno do ferrão. Diferenças são observadas entre as condições redutora e não redutora principalmente nos grupos acima de 97 kDa. A cromatografia em gel filtração não foi eficiente em separar os componentes protéicos de ambos os venenos, porém, evidencia diferenças entre os perfis. O veneno do muco contém proteínas com PI próximo a 5,0. E o ferrão deve ser composto de proteínas primordialmente aniônicas. Estes resultados mostram as importantes ações tóxicas induzidas pelos venenos do bagre marinho C. spixii, além de aspectos bioquímicos, que podem ser úteis no acompanhamento da evolução clínica e tratamento dos acidentados. / Accidents with venomous fishes are very frequent in costal waters of Brazil. Marine catfishes are the venomous fishes that cause the greatest number of accidents in Brazil, specially in southeast littoral, where the yellow-catfish Cathorops spixii (Ariidae) is the most abundant. The accidente is characterized for painful injury, intense edema and some eventul systemic symptoms; ande even these accidents are very commom,only in this decade, studies about its venoms had started. So this work intend to caracterize the main toxic activities (edema, nociception, hemorrhage, necrosis, proteolysis, alterations is vascular permeability and in microcirculation) induced by mucus and sting venom of C. spixii inmurine model (Swiss, 20-22g); besides it\'s biochemical characterization. Mucus, sting and mixture (mucus+sting) venoms were tested. In nociceptive and edematogenic assays venoms (3; 10; 30 or 60μg / 30μl sterile PBS) were injected in mice paw, whereas in hemorrhagic and necrosis assays, venoms (50; 150 or 300μg / 50μl sterile PBS) were injected in mice back. To proteolytic assay, 10; 30 or 60μg were utilized over a casein substrate. To vascular permeability assay 10; 30 or 60μg were injected by i.p. way. Whereas on microcirculation alterations 30μg were aplied over exposed cremaster muscle. All venoms induced nociception with 3 μg or more. Edema was considered significant when over 30% of control group and was induced by all venoms, too, with bottom after 2h, and continuing until 24h. Hemorrhage and necrosis weren\'t observed even so high doses were injected. Alterations on micocirculation were observed for bath venoms. 30μg increased leukocyte rolling (after 10min), blod flow stopped (after 30min, but only with mucus venom), and caused contraction on miofibres (after 40min). SDS-PAGE (12%) showed a complex pattern with several bands allover the gel. Skin and Sting venoms share some identical bands but there are important differences. Mucus venom majority bands are found between 20-30 kDa, 45-60 kDa and over 97 kDa. Sting venom major ones are between 33 kDa and 55-60 kDa. Gel- Filtration (Sephadex) showed 4 (Mucus venom) and 5 peaks (Sting venom). In this differential peak, there are molecules with high molecular weight. These results show that both venoms are able to induce important toxic activities induced by mucus and sting venoms of C. spixii. Besides, biochemical aspects that can be usefull to understand envenonming and propose better treatment.

L’étude des fluides complexes présente un grand intérêt de par la richesse des phénomènes que font intervenir leur écoulement. Une étude de rhéologie locale de systèmes de micelles géantes en microcanal droit est effectuée. L’expérience montre que les propriétés du fluide soumis à un fort gradient de contrainte ne peuvent être décrites que par une équation rhéologique comportant des termes non locaux. Nous montrons alors l’influence du système de micelles géantes, du confinement ainsi que de la nature des surfaces du microcanal sur ces effets non locaux. Une étude des phénomènes temporels intervenant dans ces écoulements en microcanaux est alors proposée, ainsi qu’une étude préliminaire concernant les écoulements dans des milieux poreux modèles. / The study of complex fluids flows is of great interest according to the diversity of phenomenon it involves. A study of the local rheology of wormlike micelles flowing in a simple straight microchannel is proposed. Experiments show that the properties of such a fluid undergoing a strong shear stress gradient can only be described by an equation including non local terms. We thereafter show the influence of the wormlike micelles system, of the confinement and of the nature of the microchannel walls on those non local effects. A study of the temporal phenomenon occurring in microfluidic flows of wormlike micelles is then proposed, as well as a preliminary study concerning flows in porous media.

This thesis comprises two manuscripts prepared for scholarly journals. Chapter 2 comprises an article entitled “Exploring Historic Changes in Musical Communication: Deconstructing Emotional Cues in Preludes by Bach and Chopin.”, which examines emotion perception in historic prelude sets by J.S. Bach and F. Chopin. This work connects psychological research on perceived musical emotion to musicological research describing changes in music structure. Using a technique called commonality analysis to deconstruct cues’ individual and joint roles in predicting participants’ perceived emotions, the chapter clarifies how music’s conveyed emotion can differ in compositions from different eras. Chapter 3 comprises an article entitled “Parsing Musical Patterns in Prelude Sets: Bridging Qualitative and Quantitative Epistemologies in Historical Music Research”. This chapter bridges gaps between qualitative and quantitative research on music history through an analytical approach engaging with both fields. Specifically, cluster analyses of Bach and Chopin’s preludes reveal notable differences in the composers’ expressive toolkits, consistent with work from historical and empirical music research. Through a novel analytical framework, the chapter illustrates a method for detecting groups of pieces demarcated by salient musical differences, assessing cues’ importance within these groups, and determining the most influential cue values for each group. Together, these articles provide new insight into the subtle sonic relationships influencing musical meaning and emotion perception. / Thesis / Master of Science (MSc) / Music’s capacity to express emotion has received considerable attention in psychological and musicological research. Whereas efforts from psychology clarify the musical cues for emotion through perceptual experiments, efforts from musicology track changes in compositional practice over time—finding changing relationships between music’s cues for emotion in historically diverse compositions. To date, the implications of these changing musical relationships for emotion perception remain unclear. This thesis analyzes musical scores and listeners’ emotion ratings to gain insight into music’s structural changes throughout history and their implications for perceived emotion. By applying statistical techniques to (i) detect musical patterns in prelude sets by J.S. Bach and F. Chopin and (ii) clarify how cue relationships influence emotion perception, this thesis sheds light on the relationship between music’s historic context and its emotional meaning.

Les fluides complexes tels que les gels, les pâtes ou les émulsions présentent une large gamme d'applications, tant dans la vie quotidienne que dans l'industrie. Parmi ces fluides, les fluides dits ”à seuil” se comportent soit comme des solides élastiques, soit comme des fluides nonnewtoniens selon la contrainte qu'on leur applique. Ces propriétés sont décrites par des lois phénoménologiques (telle que la loi d'Herschel Bulkley), bien que leurs origines soient encore mal comprises. Dans cette thèse, nous nous intéressons à la question des petites échelles, où la structure et les phénomènes interfaciaux jouent des rôles prépondérants dans les écoulements. Ce travail expérimental a été essentiellement mené sur du carbopol, un microgel de polymères et un fluide à seuil modèle. L'étude se concentre essentiellement sur trois points : – La caractérisation rhéologique et structurale des échantillons. L'accent est porté sur l'influence du protocole de préparation sur les propriétés des gels.– Le cas des écoulements confinés de fluides complexes. Ce travail met en évidence l'existence d'effets non-locaux aux échelles micrométriques, faisant intervenir une taille caractéristique interprétée dans le cadre du modèle de fluidité. – Les ascensions capillaires de fluides complexes, aux échelles millimétriques. En revisitant l'expérience classique des ascensions capillaires dans le cas des fluides complexes, cette étude propose une extension de la loi de Jurin au cas des fluides à seuil. Il est montré que cette expérience simple permet de mesurer la tension de surface et quelques paramètres rhéologiques de fluides complexes tels que le seuil et l'exposant d'Herschel-Bulkley / Complex fluids such as gels, pastes or emulsions have a wide range of applications, both in everyday life and in the industry. Among them, Yield Stress Fluids (YSF) behave either as solids or as non-Newtonian fluids depending on the shear stress applied. These features are modeled by phenomenological laws ( such as the Herschel-Bulkley one ) although their origins are still poorly understood. In this thesis, we focus on the issue of small lengthscales where the structure and interfacial phenomena play predominant roles in the flows. This experimental work was essentially carried out on carbopol, a polymer microgel and a model YSF. The study mainly focuses on three points : – The rheological and structural characterization of the samples. The emphasis is put on the influence of the preparation protocol on the microgel properties. – The case of confined flows of complex fluids. This work highlights the existence of nonlocal effects at the micrometer scales, involving a characteristic length, interpreted in the frame of the fluidity model. – Capillary ascents of complex fluids, involving millimeter scales. This work suggests an extension of Jurin’s law to the case of YSFs. It is shown that this simple experiment allows to measure the surface tension and some rheological parameters of complex fluids such as the yield stress and the Herschel-Bulkley exponent

L'interaction des rayonnements ionisants avec le vivant est marquée par des phénomènes stochastiques importants aussi bien en termes de dosimétrie physique que des effets biologiques induits. Cette thèse aborde trois problématiques de la thérapie et de l'estimation du risque des radiations pour la santé, à l'aide d'outils de modélisation et de simulations Monte Carlo. En effet, des calculs de l'énergie spécifique dans des volumes de différentes tailles ont montré que les amplitudes des fluctuations dépendent fortement de la taille de la cible. Elles sont particulièrement grandes dans le cas des cibles nanométriques. À partir de ces calculs, une étude sur la taille des dosimètres implantables pour le monitorage des traitements de radiothérapie a montré que des dimensions au moins micrométriques sont nécessaires pour assurer des mesures fiables. Les mêmes calculs ont permis l'analyse des effets de faibles doses d'irradiation, notamment la compatibilité de différentes tailles de cibles avec des données expérimentales d'aberrations chromosomiques. Les résultats suggèrent que l'activation du réseau mitochondrial peut être liée au déclenchement de mécanismes de radiorésistance dans les cellules CAL51. Finalement, un nouveau modèle (NanOx) de prédiction de l'efficacité de l'hadronthérapie (radiothérapie par faisceaux d'ions) est présenté et appliqué à la lignée cellulaire V79. Ce modèle est complètement stochastique et intègre les calculs de dosimétrie à plusieurs échelles pour modéliser des effets locaux et non locaux pouvant correspondre respectivement à des lésions de l'ADN et à un stress oxydatif / The interaction between ionizing radiation and living tissues is characterized by stochastic phenomena with non-negligible consequences both in terms of physical dosimetry and induced biological effects. The present work addresses three issues concerning radiotherapy and the estimation of radiation risks for health, by means of modeling tools and Monte Carlo simulations. Indeed, specific energy calculations in volumes of different sizes showed that the level of fluctuations strongly depends on the target size. Such fluctuations are especially high in the case of nanometric targets. Based on these calculations, a study about the size of implantable dosimeters employed in the monitoring of radiotherapy treatments demonstrated that these dosimeters should have at least micrometric dimensions in order to ensure reliable measurements. The same calculations have allowed the analysis of the effects of low doses of radiation, namely the compatibility between different target sizes and experimental data regarding chromosomal aberrations. The results suggest that the activation of the mitochondrial network may be linked to the triggering of radioresistance mechanisms for the CAL51 cell line. Finally, a new model (NanOx) to predict the effectiveness of particle therapy (radiotherapy with ion beams) is presented and applied to the V79 cell line. Such a model is completely stochastic and integrates the dosimetry calculations at multiple scales for modeling local and non-local effects, which can correspond respectively to DNA lesions and cellular oxidative stress

Les géomètres de la section Survey de l’Organisation Européenne pour la Recherche Nucléaire (CERN) utilisent le nivellement hydrostatique HLS pour effectuer des alignements verticaux précis. Le HLS atteint des précisions micrométriques, ce qui lui permet d’être utilisé pour les expériences à but de physique fondamentale comme le Large Hadron Collider (LHC). HLS mesure certes des déformations qui ont pour conséquence de désaligner tout accélérateur de particules lié au sol, mais il mesure également d’autres phénomènes aux caractéristiques bien particulières. Parmi ces phénomènes mesurés, les marées terrestres représentent une part très largement majoritaire du signal. Leur effet sur les mesures HLS est périodique et engendre une inclinaison longue base qui n’aboutit pas au désalignement relatif des aimants constitutifs d’un accélérateur. Les objectifs de ce doctorat sont de pouvoir prédire les effets ne perturbant pas l’alignement relatif d’un accélérateur de particules et ainsi corriger les mesures HLS de ces signaux. En effet, les tolérances planimétrique et altimétrique à respecter dans le domaine des accélérateurs de particules sont de plus en plus serrées. Par exemple, le Compact Linear Collider (CLIC), aujourd’hui à l’étude de faisabilité, nécessite une précision d’alignement à 3σ de 10 μm dans une fenêtre glissante de 200 m selon les directions transversale et verticale. Le HLS est candidat pour assurer cet alignement vertical mais l’amplitude de marée est d’environ +/-20 μm à 200 m, rendant nécessaire la prise en compte de ce phénomène longue base pour que l’instrumentation réponde aux besoins du CLIC. Ce doctorat est inspiré des travaux déjà réalisés sur les inclinomètres longue base et décrit les effets mesurés par HLS afin de classer ces phénomènes selon qu’ils désalignent ou non un accélérateur de particules. Enfin, les outils et modèles pour prédire les effets maitrisables sont utilisés pour anticiper les différents signaux mesurés par les HLS installés au CERN. / The surveyors of the Large Scale Metrology section of the European Organization for Nuclear Research (CERN) use hydrostatic levelling systems (HLS) to perform precise vertical alignment measurements. The HLS achieves micrometer accuracy, which allows it to be used for the fundamental physics experiments such as the Large Hadron Collider (LHC). An HLS measures the deformations that lead to the misalignment of any particle accelerator linked to the ground, but it also measures other phenomena with very particular characteristics. Among these measured phenomena Earth tides form the main part of the signal. Their effect on HLS measurements is periodic and produces a long baseline tilt that does not lead to a relative misalignment of the magnets that constitute the accelerator.The objectives of this doctoral research are to be able to predict the effects which do not disturb the relative alignment of a particle accelerator and to remove these signals from the HLS measurements. Indeed, the horizontal and vertical positioning tolerances to be respected in the realm of particle accelerators are becoming tighter and tighter. For example, the Compact Linear Collider (CLIC), currently the object of a feasibility study, requires a 3σ alignment accuracy of 10 μm in a sliding window of 200 m, in both the transverse and vertical directions. The HLS is a candidate for measuring the vertical alignment but the amplitude of the tidal effect is approximately +/-20 μm over200 m, making it necessary to take into account this long baseline phenomenon for the instrument to meet the CLIC requirements.This doctoral thesis is inspired by previous work on the long baseline tiltmeters and describes the effects measured by HLS in order to classify the measured phenomena according to whether they could produce a misalignment of a particle accelerator or not. Finally, the tools and models to predict those effects that are well understood are used to anticipate the different signals measured by HLS installed at CERN.

La capa límit atmosfèrica és l'àrea directament influenciada per la presència de la superfície de la terra i la seva alçada és d'uns centenars de metres a uns pocs quilòmetres. Durant el vespre, el refredament radiatiu estratifica establement l'aire prop del sòl i es forma el que es coneix com a Capa Límit Estable (CLE). D'avui en dia, la CLE és un règim que encara no està prou ben caracteritzat. La turbulència, que no és homogènia ni isòtropa, i la gran importància dels efectes locals com l'orografia, entre d'altres factors, dificulten l'estudi d'aquest règim. Per aquest motiu, la CLE és objecte d'especial atenció, sobretot a l'hora de millorar la seva representació en models tant de temps com de clima.Aquest treball es centra en l'estudi de la CLE mitjançant 3 eines diferents: 1) simulacions explícites de grans remolins (més conegudes com a simulacions LES), per determinar el comportament dels moviments turbulents, on les resolucions són de l'ordre de metres; 2) simulacions mesoscalars, per caracteritzar els efectes locals, on les resolucions són de l'ordre de kilòmetres; 3) anàlisi de les observacions sota aquestes condicions per tal de caracteritzar i entendre millor els fenòmens observats.En primer lloc s'estudia el rang d'estabilitats a on el model LES, que considera la teoria de Kolmogorov per la dissipació de l'energia, funciona correctament. Els resultats del model són realistes tal com mostra la seva comparació amb les mesures de dues campanyes experimentals (SABLES-98 i CASES-99). Per explorar més a fons els resultats LES i per comparar-los amb les mesures s'han utilitzat les Funcions de Distribució de Probabilitat (PDF). Aquests resultats LES són també comparables als obtinguts amb altres models LES, tal com mostra la intercomparació de models LES, més coneguda com a GABLS.Un cop desenvolupades totes les eines necessàries es fa un LES d'un cas més realista, basat en les observacions d'un màxim de vent de capes baixes (més conegut com a Low-Level Jet, LLJ). L'anàlisi combinat dels resultats LES i les mesures permet entendre millor els processos de barreja que tenen lloc a través de la inversió. Finalment, la contribució dels efectes locals s'estudia mitjançant les simulacions mesoscalars, en aquest cas centrades a l'illa de Mallorca. Durant el vespre es veu com les circulacions locals es desenvolupen a les conques (de longitud al voltant de 25km), formant-se, per exemple, vents catabàtics o LLJ com l'estudiat anteriorment. En aquest cas les simulacions es verifiquen amb imatges de satèl·lit NOAA i observacions de les estacions automàtiques de mesures, donant resultats semblants. / The atmospheric boundary layer is the area directly influenced by the presence of the Earth's surface and its height is from hundreds of meters to few kilometres. During the night, the radiative cooling stratifies the layer close to the surface and it forms the Stably-stratified Atmospheric Boundary Layer (SBL). Nowadays, the SBL is a regime not well enough characterized, yet. Turbulence, which is not homogeneous either isotropic, and the great importance of the local effects, like the orography, among other factors, make the SBL be a difficult regime to study. Even so, the SBL is an object of special attention, especially when improving its representation in numerical prediction models or climate models.This work focuses on the study of the SBL through 3 different tools: 1) Large-Eddy Simulations (LES), to determine the turbulent motions, where the resolutions are about 1m; 2) Mesoscale simulations, to characterize the local effects, where resolutions are about 1km; 3) Analysis of the observations under these conditions in order to better characterize and understand the observed phenomena.In first place, it is studied the range of stabilities where the LES model, that considers the Kolmogorov theory for the dissipation of the energy, works correctly. The results are realistic as the comparison with measures from two experimental campaigns (SABLES-98 and CASES-99) shows. To explore the results more thoroughly, and to compare the LES results to the measurements, the Probability Density Functions (PDF) have been used. The LES results are also comparable to the ones obtained with other LES models, as the intercomparison of different LES models show, better known as GABLS.Then, a more realistic case is performed using the LES model, based on observations of a Low-Level Jet (LLJ). The combined inspection of the LES results and the observations allow to better understand the mixing processes that take place through the inversion layer. Finally, the contribution of the local effects is studied through a mesoscale simulation. Here the attention is focused on the Mallorca Island. During the night, the model is able to reproduce the local circulations is a basin of a characteristic size of 25km. The main features obtained previously from the LES of the LLJ are also reproduced by the mesoscale model. These runs are verified with NOAA satellite images and observations from the automatic surface weather stations, giving that the model is able to reproduce realistic results.