Tikhonov-type regularization of linear and nonlinear ill-posed problems in abstract spaces under sparsity constraints gained relevant attention in the past years. Since under some weak assumptions all regularized solutions are sparse if the l1-norm is used as penalty term, the l1-regularization was studied by numerous authors although the non-reflexivity of the Banach space l1 and the fact that such penalty functional is not strictly convex lead to serious difficulties. We consider the case that the sparsity assumption is narrowly missed. This means that the solutions may have an infinite number of nonzero but fast decaying components. For that case we formulate and prove convergence rates results for the l1-regularization of nonlinear operator equations. In this context, we outline the situations of Hölder rates and of an exponential decay of the solution components.

The aim of the research was to establish the emotional experiences of adolescents who experience a discrepancy between their self-concept and ideal self-concept. An empirical investigation was carried out in order to establish the relationship that exists between the self-concept and the ideal self-concept of adolescents and certain emotions they experience. The investigation further identified the emotions that are prominent in the case of a discrepancy between the self-concept and the ideal self-concept. A Self-concept, Ideal Self-concept and Emotional Profile Index Questionnaire were completed by 250 adolescents. Trust and sociability showed the strongest positive correlations and depression, distrust and aggression the strongest negative correlations with aspects of the self-concept. In most instances no relationship existed between the ideal self-concept of adolescents and the emotions they experience. In terms of a discrepancy between the self-concept and the ideal self-concept, results indicated that trust was the most prominent positive emotion and depression, aggression and distrust the most prominent negative emotions. / Psychology of Education / M. Ed. (Guidance and Counselling)

Abstract Background and aims: Growing evidence supports the existence of clinically significant problems in social-emotional/behavioral (SEB) development among infants and toddlers and the importance of early identification of these problems. There is a lack of research on the occurrence and identification of problems in the SEB domain among the Finnish general population of 1 to 2-year-old children. The present study examined these important issues. Given the dearth of earlier research knowledge, particular emphasis was focused on analyzing possible moderating effects of the assessed child’s and informant’s gender on the results. Subjects and methods: Oulu toddler (N = 208, age 18 months), Oulu infant (N = 227, age 12 months), and Oulu Province (N = 1008, age 12 months) samples were collected during 2008–2013 in collaboration with child health centers. Both mothers and fathers completed questionnaires assessing their child´s SEB development (e.g. the Brief Infant-Toddler Social and Emotional Assessment; Briggs-Gowan & Carter, 2006) and the family’s sociodemographic characteristics. Child healthcare nurse (CHCN) worry reports concerning the children’s development and family well-being were also gathered. Main results and conclusions: In parental ratings, girls obtained higher SEB competence scores than boys, whereas boys got higher SEB problem scores than girls, particularly among the toddler sample. Thus, boys may have an elevated risk of parent-reported problem behaviors and delays in SEB competences even before the age of 2 years. Compared to fathers, mothers were prone to rate the toddlers higher in both SEB competences and problems, especially with regard to externalizing behavior problems and problems in boys. Elevated interparental rating differences were associated with relatively elevated maternal parenting stress. Therefore, it is recommended to gather data on young children’s SEB development from both parents when possible and to focus clinical attention on the issue if the parental reports differ significantly. Parents and CHCNs seldom recognized SEB problems and delays in competency as problematical in 1-year-old infants, even in the case of infants who were screened to be in the of-concern range on the age-appropriate measure of SEB development. Thus, further efforts are needed for developing the identification of early problems in SEB development by both parents and preventive child healthcare professionals in Finland. / Tiivistelmä Tausta ja tavoitteet: Kasvava näyttö tukee käsitystä, että kliinisesti merkittäviä sosioemotionaalisen ja käyttäytymisen (SEK) kehityksen ongelmia esiintyy jo vauva- ja taaperoikäisillä ja että näiden ongelmien varhainen tunnistaminen on tärkeää. SEK-kehityksen ongelmien esiintymisestä ja tunnistamisesta 1–2-vuotaiden väestössä Suomessa puuttuu tutkimustietoa. Tämä tutkimus arvioi näitä tärkeitä aiheita. Tutkimuksessa huomioitiin erityisesti sekä tutkittavan lapsen että arvioitsijan sukupuolen mahdollinen moderoiva vaikutus tuloksiin, koska aiempaa tutkimustietoa tästä näkökulmasta on vähän. Tutkittavat ja menetelmät: Oulu taapero (N = 208, ikä 18 kk), Oulu vauva (N = 227, ikä 12 kk) ja Oulun lääni (N = 1008, ikä 12 kk) -aineistot kerättiin vuosina 2008–2013 yhteistyössä lastenneuvoloiden kanssa. Sekä äidit että isät täyttivät lomakkeet, jotka arvioivat lapsen SEK-kehitystä (mm. the Brief Infant-Toddler Social and Emotional Assessment; Briggs-Gowan & Carter, 2006) ja perheen sosiodemografisia taustatekijöitä. Myös terveydenhoitajan raportit lapsen kehitykseen ja perheen hyvinvointiin liittyvistä huolista kerättiin. Päätulokset ja johtopäätökset: Vanhempien arvioimina tytöt saivat korkeampia pistemääriä SEK-taidoissa kuin pojat, kun taas pojat saivat korkeampia pistemääriä SEK-ongelmissa kuin tytöt, etenkin taaperoaineistossa. Pojilla saattaakin olla kohonnut riski vanhempien raportoimille käytösongelmille ja SEK-kehityksen viiveille jopa ennen 2 vuoden ikää. Isiin verrattuina äidit olivat taipuvaisia antamaan korkeampia pisteitä sekä SEK-taito- että -ongelmaosioissa taaperoikäisten aineistossa, etenkin koskien ulospäin suuntautuvia käytösongelmia ja poikien ongelmia. Suurentuneet eroavaisuudet vanhempien antamissa arvioissa olivat yhteydessä suhteellisesti kohonneeseen vanhemmuuden stressiin äideillä. Onkin suositeltavaa kerätä tietoa pienen lapsen SEK-kehityksestä kummaltakin vanhemmalta, jos mahdollista, ja kiinnittää kliinistä huomiota asiaan, jos vanhempien antamat tiedot eriävät merkittävästi. Vanhemmat ja terveydenhoitajat tunnistivat SEK-ongelmia ja taitojen puutteita harvoin huolenaiheiksi 1-vuotiailla, vaikka nämä vauvat olisivat seuloutuneet huolialueelle ikätasoon soveltuvalla SEK-kehityksen mittarilla. Tarvitaankin lisätoimia, jotta vanhemmat ja terveydenhuollon ammattilaiset oppivat paremmin tunnistamaan varhaisia SEK-kehityksen ongelmia Suomessa.

The overall purpose of this study was to explore and describe the factors that affect theory-practice integration of student nurses at a selected campus of a nursing college in the Limpopo Province. Quantitative, descriptive, explorative and cross-sectional designs were used to accomplish the objectives of the study. Data collection was done using structured questionnaires with a few open-ended questions. The respondents were student nurses (n=106) and nurse educators (n=9). The findings revealed that failure of biological and natural sciences subjects, the use of traditional teaching strategies, inadequate use of simulation laboratory, inadequate clinical supervision, a shortage of resources, nature of the assessment process, extent of interest in the subject (s) taught, inability to draw clinical experiences during theoretical teaching, overpopulation of student nurses in the clinical area, negative attitude of ward staff and differences between the simulated skills and the actual clinical procedures in the ward affect theory-practice integration. / M.A. (Health Studies) / Health Studies

In developing an understanding of real-world problems, researchers develop mathematical and statistical models. Various model selection methods exist which can be used to obtain a mathematical model that best describes the real-world situation in some or other sense. These methods aim to assess the merits of competing models by concentrating on a particular criterion. Each selection method is associated with its own criterion and is named accordingly. The better known ones include Akaike's Information Criterion, Mallows' Cp and cross-validation, to name a few. The value of the criterion is calculated for each model and the model corresponding to the minimum value of the criterion is then selected as the "best" model. / Mathematical Sciences / M. Sc. (Statistics)

La Partie I présente l’obtention du développement asymptotique topologique pour une classe d’équations elliptiques quasilinéaires. Un point central réside dans la possibilité de définir la variation de l’état direct à l’échelle 1 dans R^N. Après avoir défini un cadre fonctionnel approprié faisant intervenir les normes L^p et L^2, et avoir justifié la classe d’équations considérée, la méthode se poursuit par l’étude du comportement asymptotique de la solution du problème d’interface non linéaire dans R^N et par une mise en dualité appropriée des états direct et adjoint aux différentes étapes d’approximation.La Partie II traite d’estimations et de développements asymptotiques de p-capacités de condensateurs, dont l’obstacle est d’intérieur vide et de codimension > ou = 2. Après les résultats préliminaires, les condensateurs équidistants permettent de donner deux illustrations de l’anisotropie engendrée par un segment dans l’équation de p-Laplace, puis d’établir une minoration de la p-capacité N-dimensionnelle d’un segment, qui fait intervenir les p-capacités d’un point, respectivement en dimensions N et (N-1). Les condensateurs elliptiques permettent d’établir que le gradient topologique de la 2-capacité n’est pas un outil approprié pour distinguer les courbes des obstacles d’intérieur non vide en 2D / Part I deals with obtaining topological asymptotic expansions for a class of quasilinear elliptic equations. A key point lies in the ability to define the variation of the direct state at scale 1 in R^N. After setting up an appropriate functional framework involving both the L^p and the L^2 norms, and then justifying the chosen class of equations, the approach goes on with the study of the asymptotic behavior of the solution of the nonlinear interface problem in R^N and by setting up an adequate duality scheme between the direct and adjoint states at each step of approximation. Part II deals with estimates and asymptotic expansions of condenser p-capacities and focuses on obstacles with empty interiors and with codimensions > ou = 2. After preliminary results, equidistant condensers are introduced to point out the anisotropy caused by a segment in the p-Laplace equation, and to provide a lower bound to the N-dimensional condenser p-capacity of a segment, by means of the N-dimensional and of the (N-1)-dimensional condenser p-capacities of apoint. Introducing elliptical condensers, it turns out that the topological gradient of the 2-capacity is not an appropriate tool to separate curves and obstacles with nonempty interior in 2D

L’apprentissage statistique cherche à modéliser un lien fonctionnel entre deux variables X et Y à partir d’un échantillon aléatoire de réalisations de (X,Y ). Lorsque la variable Y prend un nombre binaire de valeurs, l’apprentissage s’appelle la classification (ou discrimination en français) et apprendre le lien fonctionnel s’apparente à apprendre la frontière d’une variété dans l’espace de la variable X. Dans cette thèse, nous nous plaçons dans le contexte de l’apprentissage actif, i.e. nous supposons que l’échantillon d’apprentissage n’est plus aléatoire et que nous pouvons, par l’intermédiaire d’un oracle, générer les points sur lesquels l’apprentissage de la variété va s’effectuer. Dans le cas où la variable Y est continue (régression), des travaux précédents montrent que le critère de la faible discrépance pour générer les premiers points d’apprentissage est adéquat. Nous montrons, de manière surprenante, que ces résultats ne peuvent pas être transférés à la classification. Dans ce manuscrit, nous proposons alors le critère de la dispersion pour la classification. Ce critère étant difficile à mettre en pratique, nous proposons un nouvel algorithme pour générer un plan d’expérience à faible dispersion dans le carré unité. Après une première approximation de la variété, des approximations successives peuvent être réalisées afin d’affiner la connaissance de celle-ci. Deux méthodes d’échantillonnage sont alors envisageables : le « selective sampling » qui choisit les points à présenter à un oracle parmi un ensemble fini de candidats et l’« adaptative sampling » qui permet de choisir n’importe quels points de l’espace de la variable X. Le deuxième échantillonnage peut être vu comme un passage à la limite du premier. Néanmoins, en pratique, il n’est pas raisonnable d’utiliser cette méthode. Nous proposons alors un nouvel algorithme basé sur le critère de dispersion, menant de front exploitation et exploration, pour approximer une variété. / Statistical learning aims to modelize a functional link between two variables X and Y thanks to a random sample of realizations of the couple (X,Y ). When the variable Y takes a binary number of values, learning is named classification and learn the functional link is equivalent to learn the boundary of a manifold in the feature space of the variable X. In this PhD thesis, we are placed in the context of active learning, i.e. we suppose that learning sample is not random and that we can, thanks to an oracle, generate points for learning the manifold. In the case where the variable Y is continue (regression), previous works show that criterion of low discrepacy to generate learning points is adequat. We show that, surprisingly, this result cannot be transfered to classification talks. In this PhD thesis, we propose the criterion of dispersion for classification problems. This criterion being difficult to realize, we propose a new algorithm to generate low dispersion samples in the unit cube. After a first approximation of the manifold, successive approximations can be realized in order to refine its knowledge. Two methods of sampling are possible : the « selective sampling » which selects points to present to the oracle in a finite set of candidate points, and the « adaptative sampling » which allows to select any point in the feature space of the variable X. The second sampling can be viewed as the infinite limit of the first. Nevertheless, in practice, it is not reasonable to use this method. Then, we propose a new algorithm, based on dispersion criterion, leading both exploration and exploitation to approximate a manifold.

Made available in DSpace on 2015-03-03T15:32:43Z (GMT). No. of bitstreams: 1 IvanildoFP_DISSERT.pdf: 6193808 bytes, checksum: 2b4b204c68da306ef20f2a99dc91d9c9 (MD5) Previous issue date: 2013-09-20 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / In general, an inverse problem corresponds to find a value of an element x in a suitable vector space, given a vector y measuring it, in some sense. When we discretize the problem, it usually boils down to solve an equation system f(x) = y, where f : U Rm ! Rn represents the step function in any domain U of the appropriate Rm. As a general rule, we arrive to an ill-posed problem. The resolution of inverse problems has been widely researched along the last decades, because many problems in science and industry consist in determining unknowns that we try to know, by observing its effects under certain indirect measures. Our general subject of this dissertation is the choice of Tykhonov?s regulaziration parameter of a poorly conditioned linear problem, as we are going to discuss on chapter 1 of this dissertation, focusing on the three most popular methods in nowadays literature of the area. Our more specific focus in this dissertation consists in the simulations reported on chapter 2, aiming to compare the performance of the three methods in the recuperation of images measured with the Radon transform, perturbed by the addition of gaussian i.i.d. noise. We choosed a difference operator as regularizer of the problem. The contribution we try to make, in this dissertation, mainly consists on the discussion of numerical simulations we execute, as is exposed in Chapter 2. We understand that the meaning of this dissertation lays much more on the questions which it raises than on saying something definitive about the subject. Partly, for beeing based on numerical experiments with no new mathematical results associated to it, partly for being about numerical experiments made with a single operator. On the other hand, we got some observations which seemed to us interesting on the simulations performed, considered the literature of the area. In special, we highlight observations we resume, at the conclusion of this work, about the different vocations of methods like GCV and L-curve and, also, about the optimal parameters tendency observed in the L-curve method of grouping themselves in a small gap, strongly correlated with the behavior of the generalized singular value decomposition curve of the involved operators, under reasonably broad regularity conditions in the images to be recovered / Problemas inversos, usualmente recaem em resolver alguma equa??o do tipo f(x) = b, onde cada equa??o fi(x) = bi pode ser pensada como uma medida de um dado x a ser recuperado. Usualmente s?o mal postos, no sentido de corresponderem a equa??es que podem n?o ter solu??o exata, podem ainda ter muitas solu??es, ou ainda, o que ? o mais comum, ter solu??es muito inst?veis a ru?dos na obten??o de b. H? v?rias formas de regularizar a obten??o de solu??es de tais problemas e a mais popular seria a de Tykhonov, que corresponde a: Minimizar ||f(x) b||2 + l ||L(x x0) ||2 (I) A regulariza??o pretendida corresponde a se escolher o operador l, de tal forma que o problema I tenha solu??es est?veis com perturba??es em b e que aproximem solu??es do problema de m?nimos quadrados usual, no caso de se fazer l 0. O primeiro termo de (I) representa o ajuste aos dados e o segundo termo penaliza a solu??o de forma a regularizar o problema e produzir uma solu??o est?vel a ru?dos. Se l = 0, isto significa que estamos procurando uma solu??o de quadrados m?nimos para o problema, o que usualmente ? insuficiente para problemas mal postos. O termo de regulariza??o adicionado introduz um vi?s na solu??o ao penalizar o ajuste com um termo adicional. Se L for a identidade, por exemplo, isto significa que estamos apostando que a solu??o estaria relativamente pr?xima de x0. Se L for o operador gradiente, estamos apostando que a solu??o x ? razoavelmente suave. Nas aplica??es, L usualmente ? escolhido como um operador adaptado ao problema estudado e de forma se valer de informa??es a priori dispon?veis sobre as solu??es procuradas. A escolha do par?metro l > 0 ? crucial neste m?todos, pelo fato que se l ? excessivo, isto tende a enfraquecer excessivamente o ajuste aos dados, induzindo um ajuste da solu??o ? x0. Se l for pequeno demais a regulariza??o pretendida acaba n?o acontecendo e a solu??o do problema (I) usualmente acaba ficando muito inst?vel e contaminada por ru?dos. H? v?rias t?cnicas dispon?veis na literatura para tal escolha, sobretudo se f ? uma fun??o linear f(x) = Ax. O objetivo da disserta??o ? o de estudar algumas destas t?cnicas de ajuste do par?metro l no caso de operadores discretizados, vale dizer, x no Rn. Em especial, destacamos os m?todos de ajuste do par?metro l reconhecidos na literatura como L-curve, GCV e m?todo da discrep?ncia, e objetiva-se comparar estes m?todos em testes feitos com a transformada de Radon e tendo como regularizador um operador de derivada de primeira ordem. Os resultados dos testes realizados revelam pontos interessantes na rela??o entre os diferentes estimadores para o par?metro de regulariza??o e que sugerem um aprofundamento te?rico al?m do escopo desta disserta??o

Le sujet principal de cette thèse est l’étude des valeurs moyennes et corrélations de fonctions multiplicatives. Les résultats portant sur ces derniers sont subséquemment appliqués à la résolution de plusieurs problèmes. Dans le premier chapitre, on rappelle certains résultats classiques concernant les valeurs moyennes des fonctions multiplicatives. On y énonce également les théorèmes principaux de la thèse. Le deuxième chapitre consiste de l’article “Mean values of multiplicative functions over the function fields". En se basant sur des résultats classiques de Wirsing, de Hall et de Tenenbaum concernant les fonctions multiplicatives arithmétiques, on énonce et on démontre des théorèmes qui y correspondent pour les fonctions multiplicatives sur les corps des fonctions Fq[x]. Ainsi, on résoud un problème posé dans un travail récent de Granville, Harper et Soundararajan. On décrit dans notre thése certaines caractéristiques du comportement des fonctions multiplicatives sur les corps de fonctions qui ne sont pas présentes dans le contexte des corps de nombres. Entre autres, on introduit pour la première fois une notion de “simulation” pour les fonctions multiplicatives sur les corps de fonctions Fq[x]. Les chapitres 3 et 4 comprennent plusieurs résultats de l’article “Correlations of multiplicative functions and applications". Dans cet article, on détermine une formule asymptotique pour les corrélations X n6x f1(P1(n)) · · · fm(Pm(n)), où f1, . . . ,fm sont des fonctions multiplicatives de module au plus ou égal à 1 ”simulatrices” qui satisfont certaines hypothèses naturelles, et P1, . . . ,Pm sont des polynomes ayant des coefficients positifs. On déduit de cette formule plusieurs conséquences intéressantes. D’abord, on donne une classification des fonctions multiplicatives f : N ! {−1,+1} ayant des sommes partielles uniformément bornées. Ainsi, on résoud un problème d’Erdos datant de 1957 (dans la forme conjecturée par Tao). Ensuite, on démontre que si la valeur moyenne des écarts |f(n + 1) − f(n)| est zéro, alors soit |f| a une valeur moyenne de zéro, soit f(n) = ns avec iii Re(s) < 1. Ce résultat affirme une ancienne conjecture de Kátai. Enfin, notre théorème principal est utilisé pour compter le nombre de représentations d’un entier n en tant que somme a+b, où a et b proviennent de sous-ensembles multiplicatifs fixés de N. Notre démonstration de ce résultat, dû à l’origine à Brüdern, évite l’usage de la “méthode du cercle". Les chapitres 5 et 6 sont basés sur les résultats obtenus dans l’article “Effective asymptotic formulae for multilinear averages and sign patterns of multiplicative functions," un travail conjoint avec Alexander Mangerel. D’après une méthode analytique dans l’esprit du théorème des valeurs moyennes de Halász, on détermine une formule asymptotique pour les moyennes multidimensionelles x−l X n2[x]l Y 16j6k fj(Lj(n)), lorsque x ! 1, où [x] := [1,x] et L1, . . . ,Lk sont des applications linéaires affines qui satisfont certaines hypothèses naturelles. Notre méthode rend ainsi une démonstration neuve d’un résultat de Frantzikinakis et Host avec, également, un terme principal explicite et un terme d’erreur quantitatif. On applique nos formules à la démonstration d’un phénomène local-global pour les normes de Gowers des fonctions multiplicatives. De plus, on découvre et explique certaines irrégularités dans la distribution des suites de signes de fonctions multiplicatives f : N ! {−1,+1}. Visant de tels résultats, on détermine les densités asymptotiques des ensembles d’entiers n tels que la fonction f rend une suite fixée de 3 ou 4 signes dans presque toutes les progressions arithmétiques de 3 ou 4 termes, respectivement, ayant n comme premier terme. Ceci mène à une généralisation et amélioration du travail de Buttkewitz et Elsholtz, et donne un complément à un travail récent de Matomäki, Radziwiłł et Tao sur les suites de signes de la fonction de Liouville. / The main theme of this thesis is to study mean values and correlations of multiplicative functions and apply the corresponding results to tackle some open problems. The first chapter contains discussion of several classical facts about mean values of multiplicative functions and statement of the main results of the thesis. The second chapter consists of the article “Mean values of multiplicative functions over the function fields". The main purpose of this chapter is to formulate and prove analog of several classical results due to Wirsing, Hall and Tenenbaum over the function field Fq[x], thus answering questions raised in the recent work of Granville, Harper and Soundararajan. We explain some features of the behaviour of multiplicative functions that are not present in the number field settings. This is accomplished by, among other things, introducing the notion of “pretentiousness" over the function fields. Chapter 3 and Chapter 4 include results of the article “Correlations of multiplicative functions and applications". Here, we give an asymptotic formula for correlations X n_x f1(P1(n))f2(P2(n)) · · · · · fm(Pm(n)) where f . . . ,fm are bounded “pretentious" multiplicative functions, under certain natural hypotheses. We then deduce several desirable consequences. First, we characterize all multiplicative functions f : N ! {−1,+1} with bounded partial sums. This answers a question of Erdos from 1957 in the form conjectured by Tao. Second, we show that if the average of the first divided difference of multiplicative function is zero, then either f(n) = ns for Re(s) < 1 or |f(n)| is small on average. This settles an old conjecture of Kátai. Third, we apply our theorem to count the number of representations of n = a + b where a,b belong to some multiplicative subsets of N. This gives a new "circle method-free" proof of the result of Brüdern. Chapters 5 and Chapter 6 are based on the results obtained in the article “Effective asymptotic formulae for multilinear averages and sign patterns of multiplicative functions," joint with Alexander Mangerel. Using an analytic approach in the spirit of Halász’ mean v value theorem, we compute multidimensional averages x−l X n2[x]l Y 16j6k fj(Lj(n)) as x ! 1, where [x] := [1,x] and L1, . . . ,Lk are affine linear forms that satisfy some natural conditions. Our approach gives a new proof of a result of Frantzikinakis and Host that is distinct from theirs, with explicit main and error terms. As an application of our formulae, we establish a local-to-global principle for Gowers norms of multiplicative functions. We reveal and explain irregularities in the distribution of the sign patterns of multiplicative functions by computing the asymptotic densities of the sets of integers n such that a given multiplicative function f : N ! {−1, 1} yields a fixed sign pattern of length 3 or 4 on almost all 3- and 4-term arithmetic progressions, respectively, with first term n. The latter generalizes and refines the work of Buttkewitz and Elsholtz and complements the recent work of Matomaki, Radziwiłł and Tao. We conclude this thesis by discussing some work in progress.

Les professionnels de l'analyse de la pratique et de l'organisation des soins interviennent dans un système complexe où interagissent des facteurs biologiques, culturels et sociaux. Ce travail de recherche porte sur les vécus du patient cardiovasculaire entrant dans un programme d'éducation thérapeutique, suite à un évènement aigu (infarctus du myocarde ou accident vasculaire cérébral). Il se justifie par la nécessité de comprendre le phénomène des récidives, rechutes et retours à l'hospitalisation malgré une prise en charge informative et éducative des facteurs de risques cardiovasculaires (tabagisme, sédentarité, mauvaise alimentation) durant l'hospitalisation initiale. Notre principal objectif est donc de comprendre ces récidives, rechutes et retours à l'hospitalisation des patients cardiovasculaires autrement que le résultat d'une non-observance. Cette recherche de type qualitatif est menée au Centre Hospitalo-Universitaire de Clermont-Ferrand (service de cardiologie court séjour) et à la clinique cardiopneumoloique de Durtol (centre de soins de suite et de réadaptation). La recherche est basée sur 22 situations d'observations de pratiques professionnelles, 9 entretiens centrés avec les professionnels dans ces 2 sites ci-dessus et 31 entretiens semi-directifs avec les patients. Ces enquêtes sont complétées par une analyse de la littérature française et anglo-saxonne, dans le domaine de l'éducation thérapeutique, de l'observance et du changement des comportements. En termes de résultats, la recherche présente les récidives, rechutes et retours à l'hospitalisation court séjour des patients comme le résultat d'une prise en charge inadaptée à leurs besoins. Des discordances de temps, de vécus et de ressentis entre professionnels de santé et patients durant l'hospitalisation initiale, l'inadaptation structurelle du court séjour, la discontinuité de la prise en charge et les ruptures de cohérence en fonction des différents niveaux de complexité (court séjour, centre de soins de suite et de réadaptation et chez les médecins traitants), mais surtout la confusion entre éducation du patient et information du patient, rendent les prescriptions médicales et soignantes en matière de changement des comportements à risques difficilement observables par les patients. Le format actuel de la relation et des interactions patients/professionnels de santé durant les soins, ne favorise pas l'implication et la participation active des patients dans leur prise en charge. En conclusion, nous retenons que les éléments qui influencent les comportements des patients vis-à-vis de leurs traitements ne relèvent pas seulement d'un apprentissage, mais de leur vécu et ressentis et également de leurs interactions avec les professionnels de santé. La prise en charge informative et éducative des facteurs de risques occulte parfois l'aspect relationnel de cette thérapeutique et les capacités cognitives et émotives des patients. Elle devrait suivre une double évolution : celle du patient (ses émotions, ses attentes, ses projets de vie…) et celle de la pathologie. Ce travail cherche également à répondre à la question suivante : en quoi et comment une approche socio-anthropologique permet-elle de comprendre les comportements des patients d'une part et des professionnels de santé d'autre part dans un contexte d'ETP en court séjour ? Il milite pour une reconnexion entre sciences sociales et sciences médicales et soignantes dans le système de soin et de santé français et montre l'apport considérable mais encore trop peu exploité des sciences sociales dans ce domaine. / The professionals of the practice analysis and care organization take part in a complex system where biological, cultural and social factors interact. This research task focuses on the experiences of the cardiovascular patient entering a therapeutic education program, after an acute event (myocardial infarction or stroke). It is justified by the need to understand the phenomenon of recurrence, relapse and hospitalization returns despite an informative and educational treatment in cardiovascular risk factors (smoking, physical inactivity, poor nutrition) during the initial hospitalization. Our main goal is therefore to understand these recurrences, relapses and hospitalization returns of cardiovascular patients other than the result of non-compliance. This qualitative research is carried out at the University Hospital Center of Clermont-Ferrand (Cardiology Department short stay) and at the cardio-pneumologic clinic of Durtol (follow-up and rehabilitation care center). The research is based on 22 observation situations of professional practices, nine focused interviews with professionals in these two sites above and 31 semi-structured interviews with the patients. These surveys are supplemented by an analysis of the French and Anglo-Saxon literature in the field of therapeutic education, compliance and behaviours change. In terms of results, the research presents the recurrences, relapses and returns to patients' short stay hospitalization as the result of an inappropriate care to their needs. Time discrepancies, experiences and felt between health professionals and patients during the initial hospitalization, inadequate structural short stay, the discontinuity of care and the inconsistencies in accordance with different levels of complexity (short stay, follow-up and rehabilitation care center and at the attending physicians', but mostly the confusion between the patient's education and the patient's information, makes medical and nursing requirements in terms of the change of risky behaviours hardly observable by patients. The current format of the relationship and the interactions patient/health professionals during the care doesn't promote the involvement and the active participation of patients in their care. In conclusion we retain that the elements which influence the patients' behaviours with respect to their treatments do not only depend on training, but on their experiences and felts and also on their interactions with health professionals. The informative and educational care of the risk factors sometimes conceals the relational aspect of this therapeutic and the cognitive and emotive capacities of the patients. It should follow a double evolution: that of the patient (his emotions, his expectations, his life plans) and that of the pathology. This work also seeks to answer to the following question: why and how a socio- anthropological approach allows us to understand the patients' behaviours on one hand and the health professionals on the other hand in a context of PTE (patient's therapeutic education) in short stay? It argues for a reconnection between social sciences and medical and nursing in the French health care system and shows the significant contribution but still too little used by social sciences in this area.