Bahia de la Ascension (BA) is a pristine, shallow, karst bay located in the Mexican Caribbean, a region experiencing rapid population growth stimulated by intense tourism development. The overall objective of this study was to address the natural hydrographic variability of this inherently vulnerable ecosystem and assess its influence on a key habitat, the seagrass. The chapters follow the three-branched nature of the study which tackled the connected ecosystem issues of coastal hydrology, physical dynamics of flow and circulation, and the ecological dynamics of the seagrass species Thalassia testudinum in BA. Freshwater input to BA is primarily by submerged groundwater discharges and surface runoff; both sources are derived from fissures in the aquifer but feature distinct water quality due to the interaction with adjacent wetlands. Hurricanes explain 36 percent of the interannual precipitation variability in the region. The water balance indicates a persistent net outflow from BA to the adjacent shelf, suggesting an intense exchange across inlets. Both diurnal and semidiurnal tidal frequencies are attenuated in the inner bay, where a meteorologically-induced subtidal water level increase may occur during four-day southeasterly winds. A clear SW-NE salinity gradient was established during dry and rainy seasons, with a strong tidally-driven marine influence throughout the central basin, and a perennial mesohaline ambient in the southwestern-most bay, where hydrodynamics are primarily controlled by wind stress. Thalassia testudinum is the dominant seagrass species in BA, occupying ~90 percent of the substrate, including the freshwater-influenced inner bay. High nutrient inputs, including phosphorus which might have limiting effects in karst environments, along with the wind-driven circulation controlling water residence times are associated with the successful development of T. testudinum (up to 1,461.23 g DW m-2) within the SW bay. Farthest into the central basin, Thalassia consistently exhibited an inverse correlation between abundance and density of shoots. This pattern was enhanced under exceptional precipitation and inputs of denuded organic matter resulting from hurricanes making landfall on this region. The relationship between nutrient distribution and the above/belowground ratio suggested that Thalassia growing in BA favors the development of the aerial component as nutrients availability increases. This study provides a basic understanding of the most important processes molding the patterns of variability exhibited by T. testudinum in Bahia de la Ascension. The salinity gradient and external nutrient supply, along with the hydrodynamic component, define the spatial scale at which the connectivity between the adjacent wetland, the bay, and the shelf may occur.

Made available in DSpace on 2014-06-11T19:24:49Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-04-29Bitstream added on 2014-06-13T20:52:36Z : No. of bitstreams: 1 scarpim_s_me_bauru.pdf: 1757017 bytes, checksum: 43e19c67a1730df49c3dc742da1383a3 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Esta pesquisa é um trabalho que tem como objetivo explorar a potencialidade do modelo da atividade de estudo articulado com a teoria do conhecimento e constituir uma modelagem inicial para o Ensino de Geometria Eucliadiana Plana, segundo o modelo da atividade de estudo. Fundamenta-se na Teoria do Conhecimento Marxista, na Psicologia Sócio-Histórica e no Experimento Formativo (EF) que ocorreu na União Soviética, sob coordenação de Daniíl B. Elkonin e Vasili V. Davidov. Parte da análise de uma Iniciação Científica na qual se apresenta um experimento didático piloto baseado no modelo da atividade de estudo, para conteúdos de Geometria Plana e número real. Apresenta um estudo a respeito da teoria do conhecimento como forma de justificar e evidenciar algumas das escolhas, tanto de organização, quanto de conteúdos que foram abordados. Aborda a teoria da atividade no seu sentido mais geral apresentando a hipótese que o ponto de partida de seu estudo teórico é o conceito de modelo de atividade. Apresenta um estudo da teoria da atividade, nos seus aspectos psicológicos gerais (Leontiev) e da teoria da atividade de estudo formulada no EF. Finalizando a dissertação, são formulados alguns apontamentos para o ensino de Geometria Euclidiana Plana a partir dos pressupostos teóricos abordados, com ênfase no significado do método de ascensão de ascensão do abstrato ao concreto para a assimilação do sistema no significado do método de ascensão do abstrato ao concreto para assimilação do sistema de conceitos desse conteúdo de Matemática. A metodologia foi a reflexão sobre o modelo de atividade de estudo subordinando o modelo lógico-dedutivo da Geometria Euclidiana Plana, de forma a obter-se uma modelagem inicial desse conteúdo segundo a atividade de estudo. Propõe, em termos de hipótese, a relação geneticamente inicial (célula) para o estudo teórico da Geometria... / This research is a theorical study that has a goal to explore the potentiality of the model of the study articulated activity with the theory of the knowledge and to build an initial molding for the study activity. It's based on the Theory of the Marxist Knowledge, in the Socio Historical Psychology and in the Formative Experiment (FE) that occurred in the Soviet Union, coordinated by Daniel B. Elkonin and Vasili V. Davidov. A part of the analyses of a Scientific Study in Which is shown that a didatic experiment based on the model of the study activity, for the content of the Plan Geometry and the real number. It presents a study regarding the knowledge theory as a way of justifying and substantiating some of the choices, as much organization as contents that there used in the study. It broaches the activity theory on its sense more general presenting the hypothesis that the foothold of its theoretical study is the conception of the activity model. It presents a study of the activity theory, on its general psychological aspects (Leontieve) and on the theory of the study activity formulated on the FE. Concluding the dissertation, some notes are made for the teaching of Plan Euclidean Geometry from the prerequisite theoretical report, with emphasis in the meaning of the method of the ascension from the abstract to the concrete for the assimilation of the concepts system of this content of the Mathematics. The Methodology was the reflexion about the model of the study activity, subordinating the model logical deductive of the Plan Euclidean Geometry, to obtain an initial molding of this second content the study activity. It proposes, in hypothesis terms, the genetically initial relation (cell) for the theorical study of the Plan Euclidean Geometry: ... (Complete abstract click electronic access below)

Made available in DSpace on 2015-09-25T12:20:15Z (GMT). No. of bitstreams: 1 PDF - Jose Carlos Antunes de Melo Parte 1.pdf: 2163935 bytes, checksum: 977de49e354ef0cb4cb04900451d8ebd (MD5) Previous issue date: 2012-12-07 / This Master's Thesis is a case study of a group of social workers who lived in rural work as sharecroppers, day laborers and residents on land of others, in the municipality of Sossego / PB and surroundings. From some public policies, particularly the Land Reform Programme of the Federal Government which resulted in the installation of programs Rural Settlements in the municipality of Sossego, these families came to the condition of farmers. The goal of this dissertation is to analyze the impact of changes in the socio-economic lives of these families, checking and contrasting socio-economic and cultural aspects of before and after becoming settled. Therefore, we analyzed the historical process particular to the lives of this group of families, observing their ways of working and organizing before the occupation of the lots, and those developed after the occupation. The analysis leads us to the study and reflection of the theme in the literature on rural settlements and analyze the collected data through questionnaires and semi-structured interviews. Finally, the study demonstrates that land reform could produce important changes in the agrarian structure of the municipality of Sossego, besides producing improved quality of life of families settled, having been assessed as positive by each of these families. / A presente Dissertação de Mestrado trata de um estudo de caso sobre um grupo social de trabalhadores rurais que vivia do trabalho como meeiros, diaristas ou moradores em terras de terceiros, no município de Sossego/PB e circunvizinhança. A partir de algumas políticas públicas, particularmente o Programa de Reforma Agrária do Governo Federal que resultou na instalação dos Programas de Assentamentos Rurais existentes no município de Sossego, estas famílias passaram à condição de agricultores familiares. O objetivo desta dissertação é analisar o impacto das mudanças sócio-econômicas na vida dessas famílias, verificando e contrapondo aspectos sócio-econômicos e culturais de antes e depois de se tornarem assentadas. Para tanto, analisamos o processo histórico particular às vidas desse grupo de famílias, observando suas formas de trabalho e organização antes da ocupação dos lotes e, as desenvolvidas após a ocupação. A análise nos remete ao estudo e reflexão do tema na literatura sobre assentamentos rurais e a análise do material coletado por meio de questionários e entrevistas semi-estruturadas. Por fim, o trabalho demonstra que a reforma agrária conseguiu produzir importante alteração na estrutura fundiária do município de Sossego, além de produzir melhoria na qualidade de vida das famílias assentadas, tendo sido avaliada como positiva por cada uma destas famílias.

Ce travail propose une étude expérimentale visant à caractériser les processus dynamiques se produisant au sein de matériaux vitreux mous. La première partie présente des mesures de diffusion de traceurs nanométriques dans la Laponite (une suspension colloïdale) obtenues par une méthode de recouvrement de fluorescence (FRAP). Cette étude montre que la diffusion varie avec la concentration de Laponite et la taille du traceur. Un modèle hydrodynamique de diffusion confinée permet de décrire quantitativement les données expérimentales. Une deuxième partie concerne l’étude expérimentale du vieillissement de matériaux vitreux. Nous testons en pratique le concept théorique de température effective. Celle-ci est obtenue grâce à la technique de FRAP par la mesure simultanée de la diffusion et la convection de sondes fluorescentes dans la Laponite en cours de prise. Contrairement à certaines mesures de la littérature, le système est bien gouverné par la température ambiante. Nous présentons ensuite une étude visant à caractériser le comportement de la Laponite cisaillée. Nous avons pour cela mis au point un dispositif permettant d’appliquer un champ électrique au système, et ainsi créer des déformations locales. L’effet obtenu s’est révélé trop faible, avec d’assez grandes incertitudes (probablement liées à la complexité du système), pour être considéré comme significatif. Enfin, nous avons étudié les propriétés du Carbopol, un fluide à seuil, en mesurant sa dynamique d’ascension par capillarité. La rugosité de surface des capillaires influe énormément sur la montée du fluide. Nous montrons aussi que l’ascension est pilotée par la rhéologie du système, notamment par le seuil d’écoulement. / This work is based on an experimental analysis of the dynamical processes which occur within soft glassy materials. The first part provides measurement results of nanotracers diffusion in Laponite (a colloidal suspension) obtained by a method of fluorescence recovery (FRAP). This study shows that the diffusion is affected by the concentration of Laponite as well as the size of the tracer. A hydrodynamic model with confined diffusion allows a quantitative description of the experimental data. In a second part, an experimental study is carried out, dealing with the aging processes of glassy materials. The theoretical concept of effective temperature is probed experimentally. The effective temperature is determined using the technique of FRAP, by simultaneously measuring diffusion and convection of fluorescent probes within the aging Laponite. Contrary to some measurements found in literature, results show that the system is controlled by the bath temperature. The following study then aims at characterizing the behavior of the sheared Laponite : an experimental device is developed in this perspective, by applying an electric field to the system and thus creating local deformations. However, the observed effect appears to be too low, with relatively large uncertainties (probably linked to the complexity of the system), which impede on the significance of our results. Finally, the properties of Carbopol, a yield stress fluid, are analyzed by measuring the dynamics of capillary rise. It is shown that the surface roughness of capillary strongly affects the rise of the fluid and that the latter is controlled by the rheology of the system, and more specifically by the yield stress value.

The military and scholars assert that the military has created an organization that is based on merit. However, statistics show that African American military men are more likely to be subjected to the military's justice system, they are less likely to promote to the most senior enlisted and officer ranks, they are more likely to receive a negative discharge, and they are disproportionately represented on the military's death row. Despite these assertions, many African-American men succeed within the military structure. Therefore, this qualitative study was conducted to examine the stories of senior field grade warrant officer African American men to determine how they succeeded in a system where others face different problems. Data were collected through interviews with 10 African-American men in the army. Data analysis using Nvivo 12 revealed 9 themes related to motivation and resilience and occupational expectations: competence in primary functional areas, aspiration, overcoming barriers to promotion, proven leadership style, mentorship, educational opportunities, establish a career roadmap, excel through army promotion system, and faith. The findings of this study may provide policy makers, recruiters, and those aspiring to become Army warrant officers (WO) insight into what may help to increase the number of African-American men aspiring to become WOs. This study may also help guide the Army in being an organization where service members are judged solely based on merit.

La famille Chaumont issue de la bourgeoisie namuroise émigre à Paris, vers 1719. Elle ne dispose d'aucun levier hors les billets financiers dévalués, gagnés dans l'approvisionnement des armées françaises des Flandres pendant le guerre de Succession d'Espagne. Elle spécule avec succès pendant la période du "Système de Law" pour construire une fortune foncière et acheter des offices de la haute administration royale.Elle construit aussi un réseau d'alliances matrimoniales avec de riches familles de noblesse récente. Par son mariage, le fils aîné est allié à Philibert Orry, futur ministre d'Etat. Il est commissionné chancelier du roi Stanislas, souverain des duchés de Lorraine et de Bar. Il reste en place vingt-neuf ans et gouverne les duchés pour le bien du royaume de France. Toute sa famille bénéficie de sa position pour obtenir charges et bénéfices lorrains dans l'administration, dans l'armée et le clergé.La troisième génération est installée dans la haute société de son temps et proche du pouvoir royal. Deux branches continuent la lignée comme intendant de province, intendant des POnts et Chaussées et évêque. La Révolution interrompt l'ascension des Chaumont proches des postes ministériels. Le rôle éminent de la famille est définitivement stoppé.Nous mettons en évidence sur trois générations, les ressorts qui font la fortune et l'ascension sociale de la famille Chaumont. Nous voulons montrer en quoi cette ascension n'est qu'un exemple parmi d'autres dans ce XVIIIe siècle et comment elle se distingue et présente des caractéristiques particulières. / Chaumont family, "bourgeois" from Namur won only depreciated bills of exchange by suppliing French armies during the wae of the Spanish succession in Flanders.They emigrated to Paris, around 1719 and speculated successfully during the 'Mississipi Bubble" to build a real estate fortune in France and buy offices in the senior royal administration.They also built a network of matrimonial alliances with rich, new ennobled families. The eldest son was related by marriage with Philibert Orry, future minister of State. He was appointed chancelor of king Stanislas, Duke of Lorraine and Bar. He stayed at this responsability for twenty-nine years and ruled the duchies for the sake of the French kingdom. The whole family benefited from the lasting appointment to obtain offices and prebends from Lorraine in the Church or the Army or the Administration.The third generation was installed in the high society, close to the royal power. Two branches still continued the family line as royal provincial intendant or director of the Roads Department or bishop. The French revolution disrupted the family's rise. THe prominent, close the king functions were definitively weakened.We highlighted the means used by the Chaumont family to realize their fortune and a very kick social rise over three generations; how this family was only one example among others but also why it was a particular case.

At the end of the fifteenth century, Hieronymus Bosch provided the foremost expression of the strict religious piety embodied by the Devotio Moderna and the impending embrace of secular humanism. As a result, Bosch's seemingly complex images provided viewers with positive messages concerning the journey of life through the use of binary symbolism. He utilized the pilgrimage motif as a guide throughout his paintings and in relation to the liminal spaces surrounding his works. This article will examine his important triptych, The Haywain, (c.1495-1516) as an example of spiritual paths taken simultaneously by both religious and contemporary figures, along with the viewers themselves. The underlying theme of Christ's Ascension in The Haywain plays out in an interwoven assortment of journeys, identified by characteristic northern and medieval Christian iconography. Christ's final journey acts as the ultimate goal and the paradigm for both the pilgrim within the triptych and the viewer. Evidence of processional celebrations mimicking pilgrimages reveals that the motifs in Bosch's works were located throughout his visual culture. Finally, an investigation of Bosch's 1505 triptych The Temptation of St. Anthony reveals that Bosch remains consistent in his use of the pilgrimage theme. Bosch worked within the context of the visual and textual culture of the Netherlandish city of ‘s-Hertogenbosch, and despite his creative style, was understood among his contemporaries as a messenger of positive piety.

L’ascension du cardinal de Fleury décrit les mécanismes ayant conduit le rejeton d’une famille de financiers « moyens » du Languedoc à devenir en 1726 le principal ministre de Louis XV. Il faut d’abord compter avec le mouvement d’ensemble de tout un lignage qui plonge ses racines dans la marchandise du lodévois depuis au moins le XVIe siècle. Le passage à la finance s’effectue avec le grand-père du cardinal et se poursuit avec son père Jean et surtout son oncle Pierre-Moïse, trésorier de France au bureau des finances de Montpellier. Ce dernier favorise la montée à Paris du jeune André-Hercule qui embrasse dès lors la carrière ecclésiastique. Les moteurs de l’ascension sont ensuite individuels et reposent sur le jeu des clientèles, avec le cardinal de Bonsy puis le cardinal de Noailles qui obtient d’un Louis XIV réticent l’évêché de Fréjus (1698) pour son protégé. La suite relève davantage de la contingence mais ne peut s’extraire du contexte religieux et, là encore, le système des fidélités. La désignation comme précepteur du futur Louis XV, quelques jours avant la mort du Grand Roi, permet à Fleury de faire sa rentrée à la Cour. L’incontestable habileté de Fleury lui permet de profiter de l’évolution politico-religieuse engagée par le Régent qui, passé une phase initiale de rapprochement avec les adversaires de la bulle Unigenitus, s’en détache bientôt. Fleury incarne un soutien modéré mais ferme. Sa proximité avec le petit roi fait le reste et le positionne en personnalité majeure. Les décès de Dubois puis de Philippe d’Orléans le laissent seul face au duc de Bourbon (1723). Trois ans seulement vont suffire à M. de Fréjus pour éliminer le premier ministre en titre. / The ascent of the cardinal of Fleury describes the mechanisms which have driven the heir of an "average" family of financiers in Languedoc to become Louis XV’s Prime Minister in 1726. It is necessary to underline at first the whole rise of a linage which plunges its roots into the merchandise in the Lodévois for at least the XVIth century. The transition to the finance is made with the cardinal’s grandfather and continues with his father Jean and especially his uncle Pierre-Moses, trésorier de France at the bureau des finances of Montpellier. The latter favors the rise in Paris of the young André-Hercule who embraces from then the ecclesiastical career. The causes of the ascent are individual and are based on the set of the clienteles, with at first the cardinal of Bonsy, then the cardinal of Noailles who obtains from reluctant Louis XIV the bishop's siege of Fréjus ( in 1698 ) for his protégé. The continuation is more a matter of contingency but cannot be extracted from the religious context and, even there, the system of the clienteles. The designation as the private tutor of the future Louis XV, a few days before the death of the Great King, allows Fleury to make his comeback to the Court. The indisputable skill of Fleury allows him to take advantage of the politico-religious evolution led by the Regent who, after an initial phase of proximity with the opponents of the Unigenitus bull, soon gets loose from them. Fleury embodies a moderate support but firm. His closeness with the small king makes of him a major actor. The death of Dubois and of Philippe of Orléans leaves him alone in front of the duke of Bourbon (1723). Three years only will be enough for M. de Fréjus to eliminate the official Prime Minister.

La conception des filtres a réponse impulsionnelle finie (RIF) peut être formulée comme un problème d'optimisation non linéaire réputé pour être difficile sa résolution par les approches conventionnelles. Afin d'optimiser la conception des filtres RIF, nous explorons plusieurs méthodes stochastiques capables de traiter de grands espaces. Nous proposons un nouvel algorithme génétique dans lequel certains concepts innovants sont introduits pour améliorer la convergence et rendre son utilisation plus facile pour les praticiens. Le point clé de notre approche découle de la capacité de l'algorithme génétique (AG) pour adapter les opérateurs génétiques au cours de la vie génétique tout en restant simple et facile à mettre en oeuvre. Ensuite, l’optimisation par essaim de particules (PSO) est proposée pour la conception de filtres RIF. Finalement, un algorithme génétique hybride (HGA) est proposé pour la conception de filtres numériques. L'algorithme est composé d'un processus génétique pur et d’une approche locale dédiée. Notre contribution vise à relever le défi actuel de démocratisation de l'utilisation des AG’s pour les problèmes d’optimisation. Les expériences réalisées avec différents types de filtres mettent en évidence la contribution récurrente de l'hybridation dans l'amélioration des performances et montrent également les avantages de notre proposition par rapport à d'autres approches classiques de conception de filtres et d’autres AG’s de référence dans ce domaine d'application. / The design of finite impulse response (FIR) filters can be formulated as a non-linear optimization problem reputed to be difficult for conventional approaches. In order to optimize the design of FIR filters, we explore several stochastic methodologies capable of handling large spaces. We propose a new genetic algorithm in which some innovative concepts are introduced to improve the convergence and make its use easier for practitioners. The key point of our approach stems from the capacity of the genetic algorithm (GA) to adapt the genetic operators during the genetic life while remaining simple and easy to implement. Then, the Particle Swarm Optimization (PSO) is proposed for FIR filter design. Finally, a hybrid genetic algorithm (HGA) is proposed for the design of digital filters. The algorithm is composed of a pure genetic process and a dedicated local approach. Our contribution seeks to address the current challenge of democratizing the use of GAs for real optimization problems. Experiments performed with various types of filters highlight the recurrent contribution of hybridization in improving performance. The experiments also reveal the advantages of our proposal compared to more conventional filter design approaches and some reference GAs in this field of application.

Ce travail présente une étude de la dynamique interfaciale de gouttes oscillantes dans une plage étendue de fréquences, en particulier dans le domaine des hautes fréquences. Nous avons développé une méthode de caractérisation de la dynamique des oscillations de gouttes, en présence d’un forçage externe imposé, sous la forme de variations de volume périodiques de faible amplitude sur une goutte attachée à l’extrémité d’un capillaire. Cette méthode permet d’identifier les modes d’oscillation des gouttes et d’en mesurer les fréquences et les taux d’amortissement. Cette méthode a été appliquée à différents systèmes liquide-liquide, en l’absence ou en présence de surfactants. Dans ce dernier cas, elle permet d’évaluer l’effet du comportement viscoélastique des interfaces sur la dynamique des oscillations. Ainsi 3 types d’interfaces ont été identifiés. Pour les interfaces de premier type (heptane/eau sans ajout de surfactant), chaque mode propre est modélisé par un oscillateur linéaire peu amorti. Les fréquences propres et les taux d’amortissement sont bien prédits par la théorie linéaire. Les interfaces de types 2 et 3 sont obtenues en ajoutant du pétrole brut à la phase dispersée. Les surfactants naturellement présents dans le pétrole (asphaltènes, résines) s’adsorbent à l’interface et lui confèrent des propriétés viscoélastiques. Pour les interfaces jeunes (type 2, moins de 20 minutes de vieillissement), les fréquences propres mesurées restent bien prédites par la théorie, qui considère des interfaces non contaminées, tandis que les taux d’amortissement sont de loin supérieurs aux valeurs théoriques. D’autre part, les interfaces vieillies (type 3) présentent des modes propres différents avec des fréquences de résonance supérieures à celles des interfaces jeunes. Dans ce cas, la dynamique de l’interface à haute fréquence est régie par l’élasticité du réseau formé par les espèces amphiphiles du pétrole brut. Les oscillations libres d’une goutte en ascension dans une phase externe stagnante, pour un système liquide-liquide sans ajout de surfactants, ont été étudiées. Les valeurs mesurées de la fréquence d’oscillation des 4 premiers modes sont en adéquation avec la théorie linéaire. Cependant les valeurs mesurées du taux d’amortissement sont très élevées par rapport aux valeurs théoriques, pour une interface non contaminée. En effet, des espèces résiduelles adsorbées à l’interface provoquent l’apparition d’un gradient de tension interfaciale par effet Marangoni et par suite une production de vorticité plus intense dans les couches-limites, ce qui conduit à l’augmentation de l’amortissement des oscillations. / We present an experimental study of oscillating drop interfacial dynamics at a wide frequency range, especially at high frequency. A characterization method of drops oscillation dynamics has been developed. The oscillations are generated by imposing low amplitude periodic variation of volume to a drop which is attached to a capillary tip. The present method is based on the identification of the drop eigenmodes and the determination of their frequencies and damping rates. It has been applied to characterize several liquid-liquid systems. Three types of interface have been identified. For interfaces of type 1 (heptane/water without added surfactant), each eigenmode is modelled by a weakly damped linear oscillator. Eigenfrequencies and damping rates are well predicted by the linear theory. Interfaces of Types 2 and 3 are obtained by adding crude oil to the disperse phase. Oil native surfactants (asphaltenes, resins) adsorb on the drop interface and provide the latter with viscoelastic behaviour. For young interfaces (type 2 with aging time below 20 minutes), eigenfrequencies remain well predicted by the theory, which deals with non contaminated interfaces, whereas the measured damping rates are significantly higher than the theoretical values. On the other hand, aged interfaces (type 3) exhibit different eigenmodes, of which eigenfrequencies are much higher than the resonance frequencies measured for the young interfaces. At high frequency, the dynamics of aged interfaces are governed by the elasticity of the network constituted by the crude oil amphiphilic species, while the dynamics of young interfaces are governed by interfacial tension. Freely decaying oscillations of a rising drop in a liquid at rest without added surfactant were also considered. Measured frequencies for the first four eigenmodes are in good agreement with the linear theory. However, measured damping rates are much higher than the theoretical rates for non contaminated interfaces. In fact, residual adsorbed species at the heptane/water interface induce Marangoni effects and thus gradients of interfacial tension. Therefore, vorticity production within the boundary layers is enhanced, which explains the observed increase of the oscillation damping rates.