Across the country, budget cuts to education have resulted in decreased funds available for extracurricular activities. This trend in policy may have a significant impact on future outcomes, as reflected in student success measures. Using two datasets that were collected over the last two decades, in the present study, the researcher assessed the relationship between participation in extracurricular activities and the future socioeconomic outcomes in respondents' lives, including post-secondary education, full-time employment status, and income. Two existing large-scale longitudinal studies of the U.S. secondary students, i.e., the National Education Longitudinal Study of 1988 (NELS: 88) and the Education Longitudinal Study of 2002 (ELS: 2002), served as data sources. As these surveys were conducted about a decade apart, the information they yielded was suitable for meeting the study aims. Generalized linear models, such as multiple regression and logistic regression analyses, by applying sample weights, were performed to examine the impacts of extracurricular activity participation on the aforementioned outcome measures. The implications of the study findings, including the comparison of the results from two different datasets collected at different time points, were interpreted with respect to school budget policy. Results from the NELS: 88 and ELS: 2002 were also compared to evaluate the trends in the characteristics and performance of U.S. high school students during the 1988-2012 period. / Ph. D.

Aquesta tesi doctoral consisteix en una sèrie de deu articles (8 publicats y 2 en premsa) basats en dades recollides a l'estudi AMICS (Asthma Multicentre Infant Cohort Study), portat a terme a Ashford (UK) a Barcelona y a Menorca. A més dels propis articles, s'inclouen una introducció i una discussió generals per a mostrar de forma conjunta les troballes i posar-les en el context de l'evidència científica actual. També s'inclou un apartat sobre les implicacions dels resultats obtinguts tant per la recerca etiològica de l'asma com per a la salut pública, així com una llista de recomanacions finals. Des de l'any 1997 soc el responsable del estudi de cohort AMICS a Menorca, que ha comptat amb diverses beques del Ministeri de Sanitat i Consum, de la Comunitat Europea i d'una fundació privada. L'objectiu inicial principal del projecte europeu era mesurar el paper del aeroal.lergens domèstics més comuns en el procés d'iniciació de l'atòpia i l'asma. La cohort de Menorca va ampliar el seus objectius incloent dades addicionals sobre dieta i nivells d'organoclorats a la sang. El projecte continua a Menorca i en el moment de presentar la tesi s'està realitzant el seguiment del 9 anys. / The present doctoral thesis consists of a series of ten articles (8 published and 2 in press) based on data collected from the Asthma Multicentre Infant Cohort Study (AMICS), carried out in Ashford (UK) and Barcelona and Menorca (Spain). In addition to the articles themselves, a general introduction and a general discussion are included to put together the findings of the articles in the light of present scientific evidence. A section on the implications for the etiologic research of asthma and for public health and a list of final conclusions are also included. I have been responsible of the AMICS cohort in Menorca since its origin in 1997, which has been funded by different grants from the Spanish Ministry of Health, the European Commission and a private foundation. The main initial objective of the European project was to measure the role of common domestic aeroallergens in the inception of atopy and asthma. The Menorca cohort extended its objectives including additional data on dietary habits and blood levels of organochlorine compounds. The project continues in Menorca and at the moment of presenting this thesis the 9 years follow-up work is being carried out.

Bakgrund: SBU (2006) efterfrågade mer evidens för Acceptance and Commitment Therapy, (ACT) mot långvarig smärta då det både är en stor orsak till lidande och en dyr samhällskostnad (87,5 miljarder kr, år 2003). Enheten för Långvarig Smärta – Avdelning, (ELS-A) är den enda vårdavdelningen i Sverige som behandlar långvarig smärta med ACT. Syfte: Att undersöka hur patienter, som för minst ett år sedan genomgått ACT-behandling på en slutenvårdsavdelning med långvariga smärttillstånd som specialitet, upplevde behandlingsmetoden och dess resultat samt sjuksköterskans roll vid behandlingen. Metod: Kvalitativ forskningsintervju med semi-strukturerade frågor tillämpades för datainsamling. Fem färdigbehandlade patienter intervjuades och därefter analyserades intervjuinnehållet i en analysmodell. Resultat: Patienterna ställde sig väldigt positiva och tacksamma till både ACT-behandlingen och resultatet av den. Alla patienter upplevde en minskning av smärtproblematik, medan själva smärtnivån inte påverkats något nämnvärt. Efter avklarad sexveckorsbehandling valde två av fem av patienterna att fortsätta vidareutbilda sig i ACT på egen hand. Patienterna upplevde både positiva och negativa delar med ACT som gruppbehandling, medan ingen ställde sig negativ till individuell träning. Sjuksköterskans roll uppfattades som väsentlig och vital för avdelningens dagliga arbete. Det mest uppskattade med sjuksköterskan var hennes höga kompetens i form av vidareutbildning och yrkeserfarenhet samt hennes ständiga närvaro på avdelningen. Slutsats: ACT som behandlingsmetod uppskattades främst för det multiprofessionella arbetet. Behandlingen gav goda resultat gällande smärtupplevelsen för patienter med diagnosen långvarig smärta. ACT var uppskattat och intervjupersoner fortsatte därför egenbehandlingen efter utskrivning från ELS-A. Sjuksköterskan var en uppskattad person med sin höga kompetens och dagliga närvaro på avdelningen. / Background: SBU (2006) has requested more evidence-based research about the efficiency of Acceptance and Commitment Therapy on chronic pain, a disease that cost Sweden 87,5 million Krona in 2003. ELS-A is today the only department in Sweden where patients diagnosed with chronic pain can enroll for treatment. The treatment at the clinic is based on the philosophy of Acceptance and Commitment Therapy (ACT). Aim: To examine how patients diagnosed with chronic pain, one year after finalized treatment at ELS-A, evaluated the method of treatment, their level of pain today, and what role the nurse had during the enrollment. Method: Qualitative research interviews with semi-structured questions were applied for data collection. Five patients were interviewed and the data was analyzed. Results: The patients were very supportive and grateful both towards the experience of the ACT treatment itself, and the results of said therapies. All five patients experienced a reduction in how their pain previously negatively affected their lives, however the level of pain they felt remained the same. After the six weeks of clinical treatment two out of five of the interviewed patients continued studying the ACT-method independently. The patients all had both positive and negative experiences from the group interactions, and found greater appreciation for the individual treatment. The nurse played an important role in the department's everyday order of business. The nurse's performance during these days of testing was excellent. Her level of higher education, work experience and work ethic during the program was most appreciated by all. Conclusion: ACT treatment was appreciated mainly for the multi-professional team. The treatment gave good results in terms of pain perception in patients with a diagnosis of chronic pain. ACT was appreciated and interviewees therefore continued self-treatment after discharged from ELS-A. The nurse was a popular team-member with her high knowledge and daily presence at the department.

OBJECTIVE: Anxiety disorders are among the most common comorbid conditions in youth with bipolar disorder (BP). We aimed to examine the prevalence, correlates, persistence (>50% of the follow-up time), and the onset of new anxiety disorders in youth with comorbid anxiety disorders and BP. METHODS: As part of the Course and Outcome of Bipolar Youth study (COBY), 446 youth ages 7 to 17, who met DSM-IV criteria for BP-I (n=260), BP-II (n=32) or operationalized criteria for BP not otherwise specified (BP-NOS; n=154) were included. Subjects were evaluated for current and lifetime Axis-I psychiatric disorders at intake using the Schedule for Affective Disorders and Schizophrenia for School-Aged Children–Present and Lifetime version (K-SADS-PL), and standardized instruments to assess functioning and family history. Subjects were followed on average 5 years using the Longitudinal Interval Follow-up Evaluation. RESULTS: Forty-four percent (n=194) of the sample met DSM-IV criteria for at least one lifetime anxiety disorder, most commonly separation anxiety (24%) and generalized anxiety disorders (16%). Nearly 20% met criteria for two or more anxiety disorders. Overall, anxiety disorders predated the onset of BP. BP-II subjects were more likely than BP-I or BP-NOS subjects to have a comorbid anxiety disorder. After adjusting for confounding factors, BP youth with anxiety were more likely to have BP-II, longer duration of mood symptoms, more severe ratings of depression, and family history of depression, hopelessness and somatic complaints during their worst lifetime depressive episode than those without anxiety. Of the 170 youth who had anxiety at intake, 80.6% had an anxiety disorder at any time during the follow-up. Most of the anxiety disorders during the follow-up were of the same type as those present at intake. About 50% of the youth had persistent anxiety, particularly Generalized Anxiety Disorder (GAD). Persistence was associated with multiple anxiety disorders, less follow-up time in euthymia, less conduct disorder, and less treatment with antimanic and antidepressant medications (all p-values≤0.05). Twenty-five percent of the sample who did not have an anxiety disorder at intake developed new anxiety disorders during follow-up, most commonly GAD. New onsets were significantly associated with being female, lower socioeconomic status, presence of attention-deficit/hyperactivity disorder and substance use disorder and more follow-up time with manic or hypomanic symptoms (all p-values≤0.05) CONCLUSIONS: Comorbid anxiety disorders are common in youth with BP, and most often predate BP onset. BP-II, a family history of depression, and more severe lifetime depressive episodes distinguish BP youth with comorbid anxiety disorders from those without. In addition, anxiety disorders in youth with BP tend to persist and new anxiety disorders onset in a substantial proportion of the sample. Careful consideration should be given to the assessment of comorbid anxiety in BP youth. Furthermore, early identification of factors associated with the persistence and onset of new anxiety disorders may enable the development of strategies for treatment and prevention. / OBJECTIUS: Els trastorns d'ansietat són les condicions comòrbides més comuns en nens i adolescents amb trastorn bipolar (TB), però fins on sabem, cap estudi ha examinat l'evolució dels trastorns d'ansietat en joves i adults amb TB. L'objectiu de l'estudi va ser examinar els factors associats amb la persistència (>50% del temps de seguiment) i l'aparició de nous trastorns d'ansietat en nens i adolescents amb TB. MÈTODE: Com a part de l’estudi Course and Outcome of Bipolar Youth (COBY), 413 nens i adolescents entre 7 i 17 anys que complien els criteris per el Manual Diagnòstic i Estadístic IV (DSM-IV) pel TB-I (n=244), TB-II (n=28) o el criteri operacionalitzat pel TB no especificat (TB-NOS; n=154) van ser reclutats principalment de consultoris d'atenció ambulatòria. Els subjectes van ser seguits de mitjana durant 5 anys utilitzant el Longitudinal Interval Follow-up Evaluation. RESULTATS: Dels 170 nens i adolescents que presentaven ansietat a l'inici de l’estudi, el 80.6% tenia un trastorn d'ansietat en qualsevol moment durant el seguiment. La majoria dels trastorns d'ansietat durant el seguiment van ser del mateix tipus que els presents a l'inici de l'estudi. Al voltant del 50% dels joves tenien persistència d'ansietat, sobretot trastorn d'ansietat generalitzada (TAG). La persistència es va associar amb trastorns d'ansietat múltiple, menys temps de seguiment en eutimia, menys trastorn de conducta i menor tractament amb medicaments antidepressius i antimaníacs. Vint-cinc per cent de la mostra que no tenien un trastorn d'ansietat a l'inici, va desenvolupar nous trastorns d'ansietat durant el seguiment, en general TAG. L'inici de nous trastorns d'ansietat es va associar significativament amb ser dona, baix nivell socioeconòmic, presència del trastorn per dèficit d'atenció i hiperactivitat, trastorn per consum de substàncies i més temps de seguiment amb símptomes maníacs o hipomaníacs. CONCLUSIONS: Els trastorns d'ansietat en nens i adolescents amb TB tendeixen a persistir i l'ansietat de nou inici apareix en una proporció substancial de la mostra. S'ha de prestar atenció a l'avaluació de l'ansietat comòrbida en nens i adolescents amb TB i la identificació precoç dels factors associats amb la persistència i l'aparició de nous trastorns d'ansietat poden permetre el desenvolupament d'estratègies pel tractament i la seva prevenció.

Comprehensive knowledge and information about the static and dynamic behaviour of machine tools, cutting processes and their interaction is essential for machining system design, simulation, control and robust operation in safe conditions. The very complex system of a machine tool, fixture and cutting tools during the machining of a part is almost impossible to model analytically with sufficient accuracy. In combination with increasing demands for precision and efficiency in machining call for new control strategies for machining systems. These strategies need to be based on the identification of the static and dynamic stability under both the operational and off-operational conditions. To achieve this it is necessary to monitor and analyze the real system at the factory floor in full production. Design information and operational data can then be linked together to make a realistic digital model of a given machining system. Information from such a model can then be used as input in machining simulation software to find the root causes of instability. The work presented in this thesis deals with the static and dynamic capability of machining systems. The main focus is on the operational stability of the machining system and structural behaviour of only the machine tool, as well. When the accuracy of a machining system is measured by traditional techniques, effects from neither the static stiffness nor the cutting process are taken into account. This limits the applicability of these techniques for realistic evaluation of a machining system’s accuracy. The research presented in this thesis takes a different approach by introducing the concept of operational dynamic parameters. The concept of operational dynamic parameters entails an interaction between the structural elements of the machining systems and the process parameters. According to this concept, the absolute criterion of damping is used to evaluate the dynamic behaviour of a machining system. In contrast to the traditional theory, this methodology allows to determine the machining system's dynamic stability, in real time under operating conditions. This framework also includes an evaluation of the static deformations of a machine tool.  In this context, a novel concept of elastically linked system is introduced to account for the representation of the cutting force trough an elastic link that closes the force loop. In addition to the elastic link which behaves as a static element, a dynamic non-contact link has been introduced. The purpose is to study the non-linear effects introduced by variations of contact conditions in joints due to rotational speed. / QC 20111123

A partir de que la participación de los jóvenes se ha vinculado al desafío democrático de fortalecer la participación de los ciudadanos tanto a nivel individual como colectivo, se ha visto un interés en potenciar el aprendizaje de competencias para participar, aprendizaje que se asociaría al ejercicio de la participación como un medio y fin desde la escuela. Con lo cual se ha estimado que la formación para participar en la sociedad democrática se encontraría entre las tareas de la pedagogía actual. Bajo esta premisa la investigación siguiente corresponde a un estudio comparativo de casos, donde se abordaron las conceptualizaciones y acciones participativas que desarrollaban los jóvenes entre 16 y 18 años en dos institutos de Chile y dos de España. Los centros fueron escogidos porque mantenían y promovía actividades participativas, con lo cual se caracterizaban en su contexto por promover la participación de los jóvenes. Los objetivos fueron describir los tipos de participación que vivían los jóvenes en sus centros educativos y comparar las experiencias entre países. Teóricamente se realizó una revisión del sentido de la participación desde la idea de la democracia deliberativa, lo que permitió comprender desde la génesis occidental de la democracia un sentido de la participación individual y colectiva, así como su alcance en los niños y jóvenes. Entendiendo por democracia la forma de tomar decisiones, un modelo de organización social y también un sistema de gobierno, que conlleva significados, valores y principios universales. Posteriormente se revisaron algunas perspectivas educativas que han promovido el reconocimiento del niño en la escuela, específicamente a través de metodologías activas y una mirada confiada y respetuosa de sus capacidades e intereses, lo cual fue identificado como uno de los principios de la participación de los niños y jóvenes en los centros educativos. Además se revisaron las teorías que relacionaban el aprendizaje de la participación con la democracia y el aprendizaje moral, junto con estudios recientes que abordaban estas experiencias en la población adolescente a nivel global y en los contextos estudiados. Ante este escenario la investigación planteó indagar en centros de secundaria donde se realizaran buenas prácticas participativas tanto en Chile como en Cataluña. Para describir las particularidades de cada centro según sus protagonistas y luego comparar los aspectos comparables. La metodología de investigación comprendió recolección de datos cualitativos y cuantitativos de los sujetos implicados (estudiantes, docentes, directivos) además de la revisión de cada caso profundamente a través de sus documentos oficiales. Los resultados se expusieron a través del análisis de cada caso en particular a través de la triangulación de la información obtenida. Luego se compararon los institutos según titularidad y país de procedencia. Entre las conclusiones destacaron que la participación en los centros analizados prevalecían tipos de participación correspondientes a Asignados pero informados (Hart, 1992) y Simple- Consultivo (Trilla y Novella, 2001), a la vez que se observó que la experiencia participativa es transformadora y formadora para los jóvenes que formaron parte de la investigación. Por último se halló que existía un énfasis en promover y valorar la democracia, en los centros investigados y que habría una generación de jóvenes, como los que formaron parte de la investigación, que propone una participación diferente a las que las instituciones ofrecen y que vale la pena revisar. / This research is a comparative case study which aimed to study the participatory conceptualizations and actions that were developed by young people aged 16 and 18 years old in two secondary schools in Chile and two in Spain. The institutions were selected because they support and promote participatory activities; therefore they were well recognized in their contexts to promote young participation. The goal was to describe the type of participation that young people experience in their educational institutions and to compare the experiences between countries. From a theoretical level, we approach the sense of the participation from the perspective of the deliberative democracy and from the understanding of the children’s right to participate. We reviewed as well the experiences related with the current of thought of democratic pedagogies together with the contemporary trends and finally the presence of the student’s participation in the legislature of both countries. Regarding this frame, we understood the student’s participation in their educational institutions as a means and a goal towards the learning of the participation, and as a valuable feature that leads people to be actively involved in the different areas of life in society. We also understood the participation as a right which articulates the essence of a democracy and the learning of the organizational skills in the common live. The research methodology involves the uses of quantitative and qualitative data, collected from the target individuals (students, teachers and directors) and also the analysis of official institutional documents. The results were exposed by single cases and by the triangulation of the information. Afterward, we compared the institutions regarding the country and the ownership (private or public). Among all the conclusions, is remarkable that the participation in the schools is not transferred to the vision of democratic experience in their scholar life, therefore it’s focused on the participation related with academic issues or student’s organization. At the same time, we consider relevant that the adults trust the participatory methodologies to promote meaningful learning, together with other factors, according each case and analysis level.

This dissertation examines the developing understandings of teacher candidates being prepared to teach ELs in general education PreK-12 classrooms. As the ethnic and linguistic diversity in U.S. classrooms continue to increase, it is crucial that teacher candidates receive high-quality, effective training in teaching culturally and linguistically diverse learners. Relatively few states currently require general education preservice teachers to participate in any formal training related to teaching ELs. The states that do have requirements and the teacher education programs within those states have the potential to provide valuable data on how the training being provided mediates the meaning making of teacher candidates preparing to enter the field of teaching. Conducted during the fall of 2016 and using survey data, class assignments, interviews, and fieldwork observations from 11 preservice teachers (eight early childhood majors; three secondary education majors), this study describes patterns in the ways that the teacher candidates made sense of artifacts (e.g., articles, experiences, interactions) available to them in a state-mandated undergraduate foundational course on teaching ELs and the accompanying fieldwork. The study uses sociocultural theory to explore how the teacher candidates use course and fieldwork artifacts to learn about ELs and about teaching ELs. By gathering data from early in the course through the end of the course, this study is able to describe the perspective transformation experienced by most of the focal participants, providing evidence of increased empathy, more nuanced beliefs, and new strategies for differentiating instruction for ELs. Despite having differing backgrounds (e.g., their race, language(s), hometown, crosscultural and crosslinguistic experiences), differing goals (e.g., their college major, anticipated areas of certification, preferred teaching position, preferred region or school district, perceived likelihood that they would teach ELs in the future), and differing orientations toward ELs at the beginning of the course (e.g., positive, ambivalent), the preservice teachers identified many of the same artifacts as mediating changes in their development. These artifacts fall into the broad categories of ELs’ stories and experiences, repeated interactions with ELs, and opportunities for application. This study suggests, therefore, that the efficacy of such courses may increase with the inclusion of the following artifacts: (a) stories, simulations, and videos from ELs’ perspectives; (b) a fieldwork component in which teacher candidates actively engage with ELs; and (c) opportunities for teacher candidates to put their developing cognition into practice through course assignments and teaching in the field. Finally, this study makes suggestions for studying the long-term study of teacher candidates’ ongoing development. / Applied Linguistics

The present dissertation aims at analyzing the interplay between initial acoustic biases and language exposure during acquisition of language in the first year of life. This is a critical period in development because it is when phonetic categories are attuned to the native language. This goal is addressed by integrating the results from two developmental studies. The first study explores the presence of asymmetries in vowel perception in infants from 4 to 12 months of age, as a function of the acoustic salience and distributional properties in the test language. The second study investigates the previous contrasting results on vowel perception in 8-month-old infants growing in bilingual environments, and in particular and their relationship with task demands and the properties of the bilingual input. The results emerging from these studies point to two developmental trends. On one hand, asymmetries in vowel perception are modulated by acoustic biases before and during perceptual reorganization, and by distributional cues after perceptual reorganization. On the other hand, discrimination abilities of 8-month-old bilinguals parallel those of monolinguals when tested with an Anticipatory Eye Movement procedure, highlighting the importance of task demands in determining infants' performance. / L'objectiu d'aquesta tesis és analitzar la dinàmica que s'estableix entre els biaixos acústics i l'experiència amb el llenguatge durant el primer any de vida. Aquest és un període decisiu durant el qual les categories fonètiques s'ajusten a les propietats de la llengua materna. Aquest objectiu s'assoleix integrant els resultats de dos estudis. En el primer estudi s'explora la presència d'asimetries en la percepció de les vocals en bebès de 4 a 12 mesos d'edat, en funció de la saliència acústica i les propietats distribucionals de la llengua. El segon estudi investiga els resultats contradictoris obtinguts amb bebès de 8 mesos d'edat bilingües, i la seva relació amb les demandes de la tasca i les propietats de l'input bilingüe. Els resultats d'aquests estudis indiquen dos tendències al desenvolupament. Per una banda, que les asimetries en la percepció de les vocals són modulades per biaixos acústics abans i durant la reorganització perceptiva i per les propietats distribucionals després de la reorganització perceptiva; per l'altra banda, els resultats mostren que les habilitats de discriminació dels bilingües de 8 mesos d'edat són corresponents a les dels monolingües quan es fa servir un procediment d'anticipació de la mirada, posant en rellevància la importància de les demandes de la tasca en determinar el rendiment dels bebès.

En la literatura científica existe una amplia descripción de las consecuencias derivadas del impacto de la psicopatología en la infancia y la adolescencia, pero existe relativamente poca información sobre la patología de la personalidad en el adolescente, asociada a trastornos clínicos del Eje I y sobre el cómo afrontan sus problemas. El objetivo principal de esta tesis es tener un mejor conocimiento acerca de la patología de la personalidad en pacientes con trastornos mentales, teniendo en cuenta su impacto a nivel individual y asistencial. Esta tesis se configura a través de diversos estudios. En el primer estudio “The influence of Personality Disorders in the Use of Mental Health Services in Adolescents with psychiatric disorders”, se ha encontrado que los adolescentes con un trastorno clínico del Eje I, que presentan una situación comórbida de patología de personalidad en comparación con aquellos que no la presentan, hacen significativamente un mayor uso de servicios psiquiátricos, tales como ingresos hospitalarios (p <.001) y urgencias psiquiátricas (p <.01). El segundo estudio “Neither too much, nor too little. The dilemma of identifying personality disorders in adolescent patients with self-reports” versó, sobre la identificación de TP en adolescentes utilizando distintas metodologías de evaluación, basadas en auto-informes y entrevista diagnóstica. Se observó una pobre concordancia entre instrumentos (medias de k entre .02 - .42). El tercer estudio “Usefulness of the International Personality Disorder Examination Screening Questionnaire for Borderline and Impulsive personality pathology in adolescents” se centró en encontrar los puntos de corte óptimos para la detección de patología de personalidad impulsiva y límite con en el instrumento de cribaje IPDE-SQ, observándose una aceptable sensibilidad y moderada especificidad para la evaluación de los trastornos de la personalidad en la adolescencia. El cuarto estudio “Prevalence and severity of categorical and dimensional personality disorders in adolescents with eating disorders” se enfoca sobre la prevalencia de patología de personalidad en adolescentes con trastorno del comportamiento alimentario (TCA), desde el punto de vista dimensional, categórico vinculándose a través del concepto de severidad. En el quinto trabajo “Subtypes of adolescents with substance use disorders and psychiatric comorbidity using cluster and discriminant analysis of MMPI-A profiles”, se replicaron hallazgos previos sobre tipologías de personalidad en sujetos con trastornos por uso de sustancias (TUS), añadiendo en este estudio el componente de la comorbilidad psiquiátrica. El sexto estudio “Dimensional model of the Personality Psychopathology Five (PSY-5) and facets in adolescents with substance use disorders and healthy controls”. Se ha encontrado que la dimensión de “Disconstraint” es un buen predictor de TUS. Por último, en el séptimo trabajo “Personalidad, psicopatología y estilos de afrontamiento: un estudio caso-control en adolescentes con trastornos del comportamiento alimentario”, profundiza acerca de la relación entre la patología de personalidad en pacientes con TCA y los estilos de afrontamiento. Los resultados de esta colección de estudios, sugieren que los trastornos de la personalidad en la adolescencia, aunque controvertidos en cuanto a su detección, diagnóstico y tratamiento, son frecuentes en los individuos que tienen problemas mentales en edades tempranas. Una mejor comprensión evolutiva de sus efectos nos permitiría identificar mejor a las personas en riesgo, pronosticando mejor el curso del desarrollo en la intervención terapéutica, reduciendo el impacto negativo en los servicios de asistencia, la clínica y las conductas de riesgo asociadas. / In the literature there is a broad description of the consequences of the impact of psychopathology in childhood and adolescence, but there is relatively little information on the association between personality pathology and both Axis I clinical disorders and use of coping strategies in adolescence. The main objective of this thesis is to provide a better knowledge of the personality pathology in patients with mental disorders, taking into account its impact at both individual and healthcare levels. This thesis is configured through seven studies (which focus of study is the identification of personality pathology in adolescence) and four specific issues around personality pathology (mental health use services, relationship with eating disorders, relationship with substance use, and coping). The results of this collection of studies suggest that personality disorders in adolescence, although controversial in terms of detection, diagnosis and treatment, are common in individuals with mental health problems at an early age. A better understanding of their developmental effects allows us to better identify people at risk, predicting the course of developing proper therapeutic interventions, reducing the negative impact on healthcare services, and the clinical risk behaviours associated.

En première partie, cette thèse présente différentes significations des termes nature et environnement, en arabe et en français. Par exemple, en arabe, il existe trois termes pour désigner le mot français "environnement". Elle identifie, dans le cadre du modèle KVP qui analyse les conceptions comme des interactions entre connaissances, valeurs et pratiques sociales, plusieurs valeurs qui sous-tendent ces définitions. Plusieurs d'entre elles sont reprises comme des objectifs de l'éducation à l'environnement : citoyenneté, autonomie, responsabilité, altruisme et solidarité (CARTAS). L'essentiel de cette thèse analyse ensuite les conceptions, et plus particulièrement les systèmes de valeurs, sur la nature et l’environnement chez des enseignants tunisiens (111 enseignants de Sciences de la Vie et de la Terre : SVT et 42 enseignants d'Histoire et Géographie : HG), chez 273 élèves de 2ème année secondaire (16-17 ans) et dans les manuels scolaires tunisiens SVT de ce niveau scolaire, édités en 2003 et 2005. Les différentes analyses effectuées (khi2, analyse des correspondances multiples et analyse en composantes principales) montrent que les élèves sont plus anthropocentrés que les enseignants SVT et HG, qui sont plutôt écolocentrés, sans différence significative entre enseignants SVT et HG. Ces systèmes de valeurs sont corrélés à certaines variables personnelles : les non bacheliers, les jeunes et les individus ayant une enfance campagnarde sont plus anthropocentrés que, respectivement, les titulaires d'un baccalauréat ou plus, les adultes et ceux ayant une enfance citadine, qui sont plus écolocentrés. Les conceptions des élèves sont dans l'ensemble conformes à celles présentes dans les manuels SVT : nature sans homme, rapport utilitaire à la nature, absence de gestion et de prévention des risques liés à l’utilisation des ressources, ce qui ne favorise pas l’acquisition des valeurs CARTAS. Les enjeux et perspectives de ces résultats sont discutés / In the first part, this thesis presents in Arabic and French various significations of nature and environment terms. For example, in Arabic, there are three terms to indicate the French word " environnement ". It identifies, within the framework of the KVP model which analyzes the conceptions as interactions between knowledge, values and social practices, several values which underlie these definitions. Several of them are taken again like environmental education objectives : citizenship, autonomy, responsibility, altruism and solidarity (CARTAS). The main part in this thesis analyzes the conceptions, and mainly the values’ systems on nature and environment for some Tunisian teachers (111 Earth and Life Sciences: ELS teachers and 42 History and Geography : HG teachers ), at 273 secondary 2nd year pupils (16-17 year-olds) and in Tunisian LSE textbooks of this school level, published 2003 and 2005. Different analyses carried out (khi2, MCA and PCA) show that pupils are more anthropocentrics than ELS and HG teachers, who are rather écolocentrics, without a significant difference between ELS and HG teachers. These values’ systems are correlated with certain personal variables: the non graduates, the youths and individuals with a country childhood are more anthropocentrics than, respectively, the graduates (baccalaureate or higher), the adults and those with a town childhood, who are more écolocentrics. Pupils’ conceptions are on the whole in conformity with those present in ELS textbooks: nature without man, utility-relation with nature, absence of management and risks prevention related to the use of the resources, which is not in favour of the acquisition of CARTAS values. Stakes and perspectives of these results are discusse