Dans un contexte où les outils numériques et le WEB permettent la diffusion et le partage massif de ressources, le défi actuel est de trouver la bonne ressource au bon moment. Pour les ressources d’enseignement, les standards de description actuels (LOM ou ScoLOMFr par exemple) ne permettent pas une description des dimensions didactiques d’une ressource. Notre thèse est une contribution pour combler ce manque, en nous situant dans le domaine de environnements informatiques pour l’apprentissage humain (EIAH). Nous nous sommes particulièrement intéressé à la description de ressources de type « énoncé avec tâche prescrite » (ETP). Nous nous sommes placé dans le cadre de la théorie anthropologique du didactique (TAD) et avons en particulier exploité la formalisation de l’approche praxéologique proposée par le cadre T4TEL. Nous proposons quatre résultats principaux. Le premier est un modèle de description didactique de ressources (M2DR) de type ETP. Il permet la description d’un ETP sur la base de critères didactiques et de déterminer son adéquation avec un curriculum. Ce modèle est construit à partir de l’exploitation d’un modèle praxéologique de référence (MPR). Le deuxième résultat est la modélisation d’intentions didactiques, utilisées pour pouvoir chercher des ETP décrits à l’aide du modèle M2DR. Le troisième résultat est un enrichissement du cadre T4TEL, en définissant une modélisation de la tâche et en introduisant la notion de type de tâches optimum. Le quatrième résultat est la définition d’un processus de construction d’une représentation ontologique d’un MPR décrit dans T4TEL à l’aide de générateurs de types de tâches. Ce processus permet une utilisation du modèle dans un cadre informatisé. Il a été appliqué à différents MPR, dans les domaines de l’algèbre élémentaire et de la numération. Ceci a permis l’utilisation du modèle M2DR pour décrire différents ETP. / In a context where digital tools and the WEB allow for the diffusion and massive sharing of resources, the current challenge is to find the right resource at the right time. Current description standards (e. g. LOM or ScoLOMFr) do not allow the description of the didactic dimensions of a learning object. Our thesis is a contribution to fill this gap from the Technology-Enhanced Learning (TEL) field point of view. We were particularly interested in the description of mathematics exercises. We conducted our work within the Anthropological Theory of Didactics (ATD) framework. More specifically, we have exploited the formalization of the praxeological approach proposed by the T4TEL framework. Our findings and propositions are four-fold. First, we proposed a didactic resource description model (M2DR) that allows the description of a mathematics exercises based on didactic criteria and determines its suitability for a curriculum. This model is based on the use of a reference epistemological model (REM). The second result is the modeling of didactic intentions, used for searching for mathematics exercises described with the M2DR model. The third result is an enhancement of the T4TEL framework defining a task model and introducing the notion of optimal types of tasks. The fourth result is the definition of a process for implementing an ontological representation of a REM described in T4TEL using types of tasks generators. This process allows the model to be used in a computerized environment. It has been applied to different REMs in the fields of elementary algebra and numeracy. That fostered the use of the M2DR model to describe different mathematics exercises.

Ce travail de thèse porte sur les micro-décisions (Comiti, Grenier & Margolinas, 1995) c’est-à-dire les décisions didactiques de l’enseignant en classe, l’objectif est de contribuer au développement d’un système informatique capable d’accompagner l’enseignant dans ses prises de décisions.Nous avons choisi d’étudier ces décisions en entrant par un savoir : la numération en cycle 2 (Tempier, 2013). Le cadre théorique retenu pour la description de ce savoir est la Théorie Anthropologique du Didactique (Chevallard, 1998) plus spécifiquement une version implémentable : T4TEL (Chaachoua, Ferraton, & Desmoulins, 2013), (Chaachoua & Bessot, 2016).Afin de modéliser l’activité du professeur au sein d’une situation didactique et de prendre en compte ses activités en dehors de cette situation nous utilisons la structuration du milieu (Margolinas, 2004). Les micro-décisions de l’enseignant sont ainsi étudiées en rapport avec son projet d’enseignement, ses observations de l’activité des élèves, ses connaissances de type épistémiques et de type histoire didactique.Notre méthode de recherche est une ingénierie didactique dont la spécificité est d’impliquer des enseignants dans les phases d’analyse et de conception. Dans le cadre de cette ingénierie nous avons conçu : (1) une simulation du matériel de numération « bûchettes » : « SimBûchettes » ; (2) une base d’exercice pour « SimBûchettes » et (3) un dispositif expérimental. Ce dispositif expérimental est composé d’un outil de simulation côté élève dont les fondements sont didactiques - « Simbûchettes » - et d’un outil d’orchestration, côté enseignant, qui lui permet de consulter et d’organiser l’activité des élèves en temps réel - instanciation du Framework Chao (Wang, 2016) pour « Simbûchettes » -. Via notre dispositif nous avons accès aux actions de l’enseignant sachant les informations consultées concernant la production de l’élève et pouvons inférer ses micro-décisions.Ce dispositif nous a permis d’observer les décisions didactiques d’un enseignant d’une classe de CE1 pendant une année scolaire et d’affiner ainsi notre modèle des micro-décisions de l’enseignant. / This thesis work deals with micro-decisions (Comiti, Grenier & Margolinas, 1995), namely teachers’ decisions in class in relation to the subject they have to teach. Our aim is to contribute to the development of a TEL (Technology Enhanced Learning) that can guide teachers in their decisions.These decisions are analyzed through a specific field: decimal number system in cycle 2 (Tempier, 2013). For the description of this field we have chosen the Anthropological Theory of Didactics (Chevallard, 1998), more specifically an implementable version: T4TEL (Chaachoua, Ferraton, & Desmoulins, 2013), (Chaachoua & Bessot, 2016).Margolinas’s model about structuring the environment (2004) is used to take into account different learning activities during a teaching session. So, teachers’ micro-decisions are studied in relation to their teaching project, their observations of pupils’ activities, their knowledge of epistemic and didactic history type.Our research method is a didactical engineering whose specificity is to involve teachers in the analysis and design stages. In this engineering we have designed (1) a simulation of counting material “counting rods”: “SimBûchettes” ; (2) a bank of exercises for “SimBûchettes” and (3) an experimental device. This device is composed of, a simulation tool whose fundations are didactic – “Simbûchettes” -, on the pupils’ side, and on the teachers’side a classroom orchestration tool which allow teachers to consult and organize pupils’ activities in real time – Chao Framework’s instantiation (Wang, 2016) for “Simbûchettes”.Via our device we have access to teachers’ actions, and we can know what information has been consulted in pupils’ work. Then we can infer the micro-decisions teachers have made.This device has allowed us to observe teachers’ decisions in a primary class (CE1, 7 years-olds) during one school year and refine our teachers’ micro-decisions model.

This thesis contains descriptions and definitions of the Iron Age Proto-Aeolic capitals from Israel - Palestine area. The modern area, which my materials cover is Israel and Jordan. The time period of the capitals is between the 9th century BC and the late 8th or the beginning of the 7th century BC. Attention has been put on issues of typological characteristics, usage and time periods of the capitals and how this, through the new examples, described here for the first time, created a new typology and usage for the Proto-Aeolic capitals.

This research achieves two main goals: First it proposes a set of extensions to the existing Opencast Matterhorn lecture video capture system, which should enhance its effectiveness and enable the collection of fine-grained datasets for further research. These extensions allow users to quickly and easily create, find, tag, annotate, and share `clipshows' of their video recorded classes both publicly and privately. Second, the tracking data generated when users create or view the clipshows using these extensions are used to analyze the efficacy of the system.

L’objectif de la thèse est d’étayer l’activité de conception expérimentale avec l’utilisation d’un environnement informatique pour l’apprentissage humain (EIAH). La conception expérimentale correspond à une partie de la démarche d’investigation qui fait l’objet de nombreuses recherches, à la fois parce que cette activité favorise l’apprentissage mais aussi parce que c’est une tâche complexe à l’origine de difficultés identifiées.La situation que nous avons choisie est la mise en évidence de la fermentation alcoolique, thème abordé en classe de terminale scientifique de spécialité en sciences de la vie et de la terre. Les élèves doivent concevoir une expérience pour mettre en évidence ce métabolisme.La première étape de la thèse a consisté à effectuer une modélisation didactique des connaissances en jeu. Pour cela nous nous plaçons dans le cadre de la théorie anthropologique du didactique et plus précisément l’approche praxéologique (Bosch & Chevallard, 1999). Nous avons ainsi obtenu un premier résultat qui est la modélisation d’une praxéologie de référence à partir d’une analyse épistémologique des savoirs en jeu et des attentes institutionnelles.Afin d’aider les élèves dans cette activité à l’origine de difficultés, nous utilisons des supports d’étayage, portés par la plateforme informatique, LabBook. Cet EIAH structure des rapports expérimentaux, à l’aide de plusieurs outils (texte, tableur, dessin, protocole) mis à disposition des élèves. L’outil protocole « Copex », permet de pré structurer un protocole expérimental.La deuxième étape de la thèse a été de proposer un protocole pré structuré en étapes, actions et paramètres d’actions qui prend en charge les difficultés attendues, et de l’implémenter dans LabBook, en tenant compte des contraintes de l’EIAH.L’étape suivante a été de tester l’efficacité de la prise en charge de ces difficultés dans la situation proposée en classe. Pour cela nous avons ainsi réalisé deux expérimentations en classes de terminale scientifique dans trois lycées différents. Nous avons recueilli les productions des élèves ainsi que leur réponse à des questionnaires (pré-test et post-test).L’analyse des résultats a montré que l’activité proposée favorise les apprentissages des concepts en jeu, et fait évoluer les conceptions des élèves.Concernant la conception du protocole, la pré structuration proposée aide les élèves à produire des protocoles communicables et pertinents.A partir des praxéologies personnelles modélisées a priori nous avons mis en évidence la présence de praxéologies personnelles d’élèves.Les analyses effectuées ont permis de faire évoluer la situation proposée et de valider la proposition de pré structuration du protocole en étapes et en actions paramétrées.Enfin nous proposons des préconisations pour un diagnostic automatique des erreurs des élèves, dans le but de produire des rétroactions élaborées à partir du modèle praxéologique développé dans la thèse. / The thesis work involves a scaffold of the experimental design activity carried out by high school students in scientific activities using a TEL system (Technology Enhanced Learning).This type of activity promotes learning, but it is also a complex task that leads to difficulties identified in the literature. The situation highlights a specific cellular metabolism, the alcoholic fermentation, this topic being studied in high school biology classes. Students have to design an experimental procedure to highlight this metabolism.The first step of the thesis consisted in knowledge modelling for designing an experimental situation in biology. The framework used to model knowledge, is the Anthropological Theory of Didactics (ATD) and more precisely the praxeology model (Bosch & Chevallard, 1999). An epistemological analysis has been done in order to identify difficulties in this situation: difficulties related to knowledge and also to experimental procedure.A structured procedure was modelled into steps, actions and parameters, which takes into account difficulties identified a priori and implemented in a web environment named LabBook,.This TEL system offers fixed scaffolds in order to help students in an experimental design activity.The situation implemented in LabBook has been tested in three biology classes in high school, during two sets of experimentation. The analysis is based on the students’ productions and their answers to questionnaires (pre-test and post-test).The results analysis showed that the experimental design activity promotes learning and changes students’ conceptions. Regarding design experiment, the pre structuration helps students to produce relevant and communicable procedures.This reveals that students are able to use the pre-structured experimental procedure tool in LabBook.This is a requirement for students’ errors diagnosis in order to propose automatic personalised feedbacks. We make recommendations for such feedbacks based on the praxeology model developed in this thesis.

Translocation t(12;21) with the presence of the fusion gene ETV6-RUNX1 (TEL-AML1) is the most common chromosomal aberration found in acute lymphoblastic leukemia in childhood. The occurrence of the ETV6-RUNX1 is associated with excellent prognosis and high sensitivity to the treatment with the enzyme L-asparaginase (ASNase). Resistance to the drug aggravates the outlook of the patient and increases the risk of treatment failure, therefore, the CLIP working group has been for a long time involved in the identification of the mechanism of action of ASNase and the origin of the resistance to it. This thesis follows previous findings of the group and is devoted to the analysis of the importance of ETV6-RUNX1 and signalization and metabolic changes accompanying shifts in the L-asparaginase resistance. In the first part of the thesis, the knockout clones with stable increased resistance to ASNase have been established thanks to the CRISPR/Cas9 system, which created frameshift in the fusion gene. The accomplishment in this regard and removal of the fusion protein was confirmed on the level of DNA, mRNA a protein expression. The presence of other significant chromosomal aberrations affection the sensitivity to ASNase was ruled out by the means of SNP analysis. In the second part of the project, the signalization...

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-03-10T22:12:31Z No. of bitstreams: 1 MariaAparecidaFernandes_DISSERT.pdf: 1521396 bytes, checksum: d1543fe188d65d762caa9c3089c5b341 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-03-17T23:45:01Z (GMT) No. of bitstreams: 1 MariaAparecidaFernandes_DISSERT.pdf: 1521396 bytes, checksum: d1543fe188d65d762caa9c3089c5b341 (MD5) / Made available in DSpace on 2016-03-17T23:45:01Z (GMT). No. of bitstreams: 1 MariaAparecidaFernandes_DISSERT.pdf: 1521396 bytes, checksum: d1543fe188d65d762caa9c3089c5b341 (MD5) Previous issue date: 2015-03-26 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico - CNPq / A fam?lia Acanthuridae ? um grupo bastante representativo dentre os peixes marinhos e que desempenha um papel fundamental na din?mica ecol?gica dos recifes de corais. Tr?s esp?cies pertencentes ao g?nero Acanthurus s?o comuns ao longo dos recifes costeiros do Atl?ntico Ocidental: A. coeruleus, A. bahianus e A. chirurgus. No presente estudo, s?o apresentados dados citogen?ticos para estas tr?s esp?cies de Acanthurus com base em m?todos citogen?ticos cl?ssicos e no mapeamento de sequ?ncias ribossomais repetitivas, como DNAr 18S e 5S, al?m de sondas telom?ricas com a finalidade de auxiliar na compreens?o da carioevolu??o deste grupo. O padr?o citogen?tico dessas esp?cies indica que as etapas sequenciais de rearranjos cromoss?micos, que datam 19-5 milh?es de anos atr?s (Ma), s?o respons?veis por suas diferen?as interespec?ficas. Acanthurus coeruleus (2n=48; 2sm + 4st + 42a), A. bahianus (2n=36; 12m + 2sm + 4st + 18a) e A. chirurgus (2n=34; 12m + 2sm + 4st + 16a) compartilham um antigo conjunto de tr?s pares cromoss?micos originados atrav?s de invers?es peric?ntricas. Um conjunto de seis grandes pares metac?ntricos formados por transloca??es Robertsonianas (Rb) encontrado em A. bahianus e A. chirurgus e uma suposta fus?o em tandem presente em A. chirurgus s?o eventos mais recentes. A falta de sequ?ncias telom?ricas intersticiais (ITS), apesar de v?rias fus?es c?ntricas em A. bahianus e A. chirurgus pode estar relacionada com o longo per?odo de tempo ap?s a sua ocorr?ncia (estimado em 5 Ma). Al?m disso, as homeologias entre os pares de cromossomos que carregam os genes ribossomais, al?m de outras caracter?sticas estruturais, destacam grandes regi?es cromoss?micas conservadas nas tr?s esp?cies. Nossos resultados indicam que as mudan?as macroestruturais ocorreram durante a cladog?nese dessas esp?cies n?o foram seguidas por rearranjos microestruturais vis?veis nos cari?tipos. / The Acanthuridae family is a representative group from the marine fish that plays a key role in ecological dynamics of coral reefs. Three species are common along coastal reefs of Western Atlantic: Acanthurus coeruleus, Acanthurus bahianus and Acanthurus chirurgus. In the present study, cytogenetic data are presented for these three species Acanthurus based on classical cytogenetic methods and mapping of repetitive sequences such as ribosomal 18S and 5S rDNA and telomeric repeats to improve their karyotype evolutionary analyses. The cytogenetic pattern of these species indicated sequential steps of chromosomal rearrangements dating back 19 to 5 millions of years ago (M.a.) that accounted for their interspecific differences. A. coeruleus (2n=48; 2sm+4st+42a), A. bahianus (2n=36; 12m+2sm+4st+18a) and A. chirurgus (2n=34; 12m+2sm+4st+16a) share an older set of three chromosomal pairs that were originated through pericentric inversions. A set of six large metacentric pairs formed by Robertsonian (Rb) translocations found in A. bahianus and A. chirurgus and a putative in tandem fusion found in A. chirurgus are more recent events. The lack of interstitial telomeric sequences (ITS) in spite of several centric fusions in A. bahianus and A. chirurgus might be related to the long period of time after their occurrence (estimated in 5 M.a.). Furthermore, the homeologies among the chromosome pairs bearing ribosomal genes, in addition to other structural features, highlight large conserved chromosomal regions in the three species. Our findings indicate that macrostructural changes occurred during the cladogenesis of these species were not followed by conspicuous microstructural rearrangements in the karyotypes.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-04-17T23:20:36Z No. of bitstreams: 1 BrunaSilvaOliveira_TESE.pdf: 2168230 bytes, checksum: e104821a58eb464892a9329229db3c08 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-04-20T23:37:21Z (GMT) No. of bitstreams: 1 BrunaSilvaOliveira_TESE.pdf: 2168230 bytes, checksum: e104821a58eb464892a9329229db3c08 (MD5) / Made available in DSpace on 2017-04-20T23:37:21Z (GMT). No. of bitstreams: 1 BrunaSilvaOliveira_TESE.pdf: 2168230 bytes, checksum: e104821a58eb464892a9329229db3c08 (MD5) Previous issue date: 2016-11-25 / Introdu??o: o comprimento do tel?mero (TL) tem sido apontado como um poss?vel biomarcardor do envelhecimento celular, pois ocorre encurtamento fisiol?gico e progressivo do seu tamanho com o decorrer das replica??es celulares. Adicionalmente a esse encurtamento fisiol?gico, a disfun??o do TL tamb?m ? favorecida pela exposi??o ao estresse oxidativo, a inflama??o e ap?s o estresse psicossocial cr?nico. Existe ainda uma lacuna de conhecimento sobre as altera??es do TL durante o curso de vida em popula??es de mulheres idosas brasileiras, havendo a necessidade de estudos que possibilitem melhor entendimento da influ?ncia de contrastes sociais, condi??es socioecon?micas desfavor?veis, bem como exposi??o ao estresse social cr?nico no TL. Objetivos: 1) desenvolver uma revis?o sistem?tica para explorar as evid?ncias sobre associa??es entre estresse cr?nico durante o curso de vida e TL; 2) investigar poss?veis associa??es entre TL e adversidades na inf?ncia (social e econ?mica) em mulheres idosas com diferentes n?veis de escolaridade; 3) avaliar se o TL est? relacionado com doen?as cr?nicas e biomarcadores inflamat?rios em mulheres idosas; e 4) verificar se tel?meros mais curtos est?o associados com pior desempenho f?sico e maior autorrelato de limita??es funcionais em idosas. Materiais e m?todos: foi desenvolvida uma revis?o sistem?tica seguindo protocolo publicado em 2014. Concomitantemente, realizou-se um estudo observacional anal?tico de car?ter transversal com uma amostra de mulheres (n=106) com diferentes n?veis de escolaridade (ensino m?dio incompleto e ensino m?dio completo) na faixa et?ria de 64-74 anos e residentes no munic?pio de Natal (Rio Grande do Norte). Os dados foram coletados no per?odo de maio de 2014 a mar?o de 2015. A quantifica??o relativa do tamanho dos tel?meros (T/S) de leuc?citos foi realizada por meio da qPCR em tempo real em 83 mulheres. O question?rio padronizado incluiu informa??es sociodemogr?ficas, adversidades na inf?ncia, medidas antropom?tricas, autorrelato de sa?de, fun??o cognitiva, h?bitos de vida, condi??es cr?nicas de sa?de, capacidade funcional e desempenho f?sico (short physical performance battery, velocidade da marcha e for?a de preens?o manual). Foram analisados tamb?m biomarcadores inflamat?rios (interleucina-6 e prote?na c reativa). Para an?lise estat?stica, foram considerados p<0,05 e intervalos de confian?a de 95%. A normalidade dos dados foi verificada por meio do teste de Kolmogorov-Smirnov. Uma vez que o TL apresentou distribui??o n?o normal, foi realizada a transforma??o da medida em logaritmo natural para as an?lises subsequentes. Foram aplicados os testes T de Student para amostras independentes, Qui-quadrado e realizados modelos de regress?o linear m?ltipla ajustados pelos potenciais fatores de confus?o. Resultados: na revis?o sistem?tica, os resultados foram relatados de acordo com o Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Considerando os dezoito estudos inclu?dos na revis?o, no geral, observou-se que indiv?duos expostos ao estresse cr?nico, caracterizado por pobreza, exposi??o ? viol?ncia e cuidar de familiar doente apresentaram tel?meros mais curtos em rela??o aos indiv?duos n?o expostos ?s adversidades. An?lises do estudo transversal sobre TL e curso de vida mostraram que as idosas com ensino m?dio incompleto apresentaram maior TL em compara??o com o grupo de ensino m?dio completo (2.8 ? 0.9 e 2.0 ? 0.9, respectivamente; p = 0,0001). As mulheres que n?o conclu?ram o ensino m?dio foram expostas a mais adversidades na inf?ncia, e entre estas, as que sofreram duas ou mais adversidades apresentavam TL mais longo do que as mulheres expostas a ?1 adversidades (p = 0,03); entre as mulheres com, no m?nimo, ensino m?dio completo, essa diferen?a n?o foi significativa (p = 0,49). Em an?lises ajustadas por idade, escolaridade e abuso parental de ?lcool, observou-se tend?ncia linear de maior TL com maior n?mero de adversidades (p = 0,02) e a diferen?a no TL entre os n?veis de escolaridade permaneceu significativa (p = 0,002). N?o se observou diferen?a entre os grupos educacionais em rela??o ?s seguintes vari?veis: colesterol, triglic?rides, glicemia em jejum, hemoglobina glicada, prote?na c reativa e interleucina-6 (p>0,05). Condi??es cr?nicas de sa?de, medidas antropom?tricas, fatores de risco cardiovasculares e marcadores inflamat?rios n?o foram associados com o TL, mesmo ap?s o ajuste para idade, escolaridade e adversidades na inf?ncia (p>0,05). Igualmente, o TL n?o foi relacionado com nenhuma das vari?veis utilizadas para avaliar o desempenho f?sico e a capacidade funcional (p>0,05). Conclus?es: a rela??o positiva inesperada entre menor escolaridade e adversidades na inf?ncia com TL sugere que os participantes sobreviveram a duras condi??es de vida e que, provavelmente, essas mulheres t?m o TL mais longo em rela??o ao daquelas de sua coorte de nascimento. A aus?ncia de rela??o entre TL e doen?as cr?nicas, risco cardiovascular, inflama??o e desempenho f?sico, n?o deu suporte ? hip?tese de que o TL ? um biomarcador do envelhecimento na popula??o em estudo, por?m corrobora outros estudos que revelaram que o TL pode ser considerado um marcador de longevidade, independentemente de condi??es de sa?de e desempenho f?sico. / Introduction: Telomere length (TL) has been pointed out as a possible biomarker of cellular aging, as its physiological size progressively shortens with the course of cellular replications. In addition to this physiological shortening, TL dysfunction is also stimulated by exposure to oxidative stress, inflammation and after chronic psychosocial stress. There is also a lack of knowledge about TL changes during the course of life in populations of older Brazilian women, and there is a need for studies which foster a better understanding of the influence of social contrasts, unfavorable socioeconomic conditions, as well as exposure to chronic social stress in TL. Objectives: 1) To develop a systematic review to explore the evidence on associations between chronic stress over the life course and TL; 2) To investigate possible associations between TL and childhood adversities (social and economic) in older women with different levels of education; 3) To evaluate whether TL is related to chronic diseases and inflammatory biomarkers in older women; and 4) To verify whether shorter telomeres are associated with poorer physical performance and higher self-reported functional limitations in older adults. Materials and methods: A systematic review was developed following a protocol published in 2014. An observational cross-sectional analytical study was concomitantly carried out with a sample of women (n = 106) with different levels of education (incomplete secondary education and complete secondary education) in the age group of 64-74 years residing in the municipality of Natal (Rio Grande do Norte). Data were collected from May 2014 to March 2015. The relative quantification of leukocyte telomere size (T/S) was performed by real-time qPCR in 83 women. The standardized questionnaire included sociodemographic information, childhood adversities, anthropometric measures, self-reported health, cognitive function, life habits, chronic health conditions, functional capacity and physical performance (short physical performance battery, gait speed and manual grip strength). Inflammatory biomarkers (interleukin-6 and c-reactive protein) were also analyzed. For statistical analysis, p<0.05 and 95% confidence intervals were used. The normality of the data was verified by the Kolmogorov-Smirnov test. Since TL presented non-normal distribution, the transformation of the measure into natural logarithm was performed for subsequent analyzes. Student's t-tests were applied for independent samples, and Chi-square and multiple linear regression models were adjusted for potential confounding factors. Results: The results of the systematic review were reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Considering the eighteen studies included in the review, we generally observed that individuals exposed to chronic stress, characterized by poverty, exposed to violence and/or caring for a sick relative had shorter telomeres compared to individuals who were not exposed to adversity. Analyzes of the cross-sectional study on TL and life course showed that the older adults with incomplete secondary education presented higher TL compared to the group of complete secondary education (2.8 ? 0.9 and 2.0 ? 0.9, respectively; p = 0.0001). Women who did not complete high school were exposed to more adversity in childhood, and among them, those who suffered two or more adversities had longer TL than women exposed to ?1 adversity (p = 0.03); among women with at least complete secondary education, this difference was not significant (p = 0.49). In analyzes adjusted for age, educational level and parental alcohol abuse, a linear trend of higher TL for greater number of adversities (p = 0.02) was observed, and the difference in TL between education levels remained significant (p = 0.002). No difference between the education groups was observed for the following variables: cholesterol, triglycerides, fasting glycemia, glycated hemoglobin, c-reactive protein and interleukin-6 (p>0.05). Chronic health conditions, anthropometric measures, cardiovascular risk factors and inflammatory markers were not associated with TL, even after adjusting for age, schooling and childhood adversities (p>0.05). Similarly, TL was not related to any of the variables used to assess physical performance or functional capacity (p>0.05). Conclusions: The unexpected positive relationship between TL and lower education level and childhood adversities suggests that participants survived harsh living conditions and that these women probably have longer TL in relation to others among their birth cohort. The lack of relationship between TL and chronic diseases, cardiovascular risk, inflammation and physical performance did not support the hypothesis that TL is an aging biomarker in the population under study, but corroborates other studies that have shown TL to be considered as a marker of longevity, regardless of health conditions and physical performance.

Philosophiae Doctor - PhD / Many teaching and learning practices in higher education, including social work education in South Africa, tend to be characterised by a transmission mode of instruction, whereby knowledge moves from the expert educator to the student. This study investigates the extent to which an authentic learning framework can be used to improve the teaching of meso practice in social work to a class of 80 second-year students at the University of the Witwatersrand, South Africa. A modified version of educational design-based research, was deployed which created a set of guidelines to inform future research and course design. Design-based research includes an iterative process, however, and the four-phased modified version of design-based research used in this study deploys just one roll-out of a redesigned course on meso practice, using the elements of authentic learning (Herrington, Reeves & Oliver, 2010). Phase 1 consisted of a review of the literature on meso practice education and the authentic learning framework. Phase 2 involved an analysis of practical problems identified by six educators and four field instruction supervisors, based on the way they teach and supervise students in the area of meso practice intervention. In Phase 3 the course was implemented and evaluated qualitatively and quantitatively by the student participants and four field instruction supervisors. Phase 4 consisted of a reflection on the entire process, to produce design guidelines using the elements of authentic learning and the inclusion of affect in course design. Mixed-methods research was undertaken, incorporating primarily qualitative data with quantitative data from a survey conducted with the students. Findings from this study have led to an augmented list of authentic learning elements, which includes the use of affect in meso practice and the development of guidelines for educators which have the potential to be relevant and applicable in other courses, contexts and disciplines. / NRF / Pillay, R. (2017). Crafting a meso practice course using elements of authentic learning for undergraduate social work students in South Africa. PhD thesis. University of the Western Cape

L'acide nitrique est largement utilisé dans le procédé de retraitement du combustible nucléaire usé, le procédé PUREX (Plutonium and Uranium Refining by EXtration). Ce procédé est fondé sur l'extraction liquide-liquide de l'uranium et du plutonium aux degrés d'oxydation (+VI) et (+IV) respectivement. Le plutonium est ensuite désextrait, et ainsi séparé de l'uranium par ajout d'uranium (+IV) stabilisé en milieu acide nitrique par des ions hydrazinium (N2H5+). Or, la radiolyse de l'acide nitrique, inhérente à la présence d'émetteurs α dans ces solutions, génère des espèces radicalaires et moléculaires susceptible de modifier, d'une part, le comportement redox des actinides et, d'autre part, de réagir avec les ions hydrazinium. Le but de ce travail est de mieux maîtriser les paramètres chimiques et physico-chimiques susceptibles de modifier les degrés d'oxydation de l'uranium et du plutonium dans les solutions d'acide nitrique. Parmi ces paramètres, le rôle de l'acide nitreux et du peroxyde d'hydrogène, générés par radiolyse de l'acide nitrique, est primordial. L'objectif est de repréciser les cinétiques de formation du peroxyde d'hydrogène et de l'acide nitreux par radiolyse alpha des milieux acide nitrique / nitrate de sodium en fonction des paramètres : acidité, concentration des ions nitrate et transfert d'énergie linéique du rayonnement ionisant.Il a été montré que la formation de peroxyde d'hydrogène diminue avec l'augmentation de la concentration des ions nitrate et augmente fortement avec l'acidité de la solution, jusqu'à atteindre une valeur stationnaire pour une acidité proche de 0,2 mol L-1. Pour sa part, la formation de l'acide nitreux est favorisée par l'augmentation de la concentration des ions nitrate. Il a été observé que G(HNO2) évolue selon deux tendance distincte, la première dans les solutions diluées d'ions nitrate et la seconde dans les solutions concentrées d‘ions nitrate. Ces deux variations traduisent des phénomènes radiolytiques directs et indirects modifiant les mécanismes de formation de HNO2. L'étude de l'acidité des solutions irradié a montré que la formation de H2O2 et de HNO2 est favorisé avec l'augmentation de la concentration des ions hydronium, jusqu'à atteindre une valeur stationnaire pour une acidité proche de 0,2 - 0,5 mol L-1.Par ailleurs, les effets induits par la nature du rayonnement ionisants (,,,…), sur les rendements de formation de H2O2 et HNO2, ont été étudiés. Il a été montré que le transfert d'énergie linéique (TEL), compris entre 0,2 keV µm-1 (caractéristique d'un rayonnement gamma) et 130 keV µm-1 (caractéristique d'un rayonnement alpha émis par la décroissance radioactive d'un actinide), a une influence significative sur les rendements de formation de H2O2 et de HNO2. Il a été observé que l'impact des ions nitrate sur le rendement de formation de H2O2 devient plus marqué, lorsque le TEL augmente. A contrario, l'impact des ions nitrate favorisant le rendement de formation de HNO2, diminue lorsque le TEL augmente. Sur la base des résultats acquis durant cette étude et des données présentes dans la littérature, deux équations paramétriques ont été développées. L'intérêt de cette paramétrisation des effets est de prédire les rendements radiolytiques de formation de H2O2 et de HNO2 selon les conditions chimique du milieu ([NO3-] ≤ 4 mol L-1 et 10-5 mol L-1 ≤ [H+] ≤ 4 mol L-1) et selon la nature du faisceau (TEL compris entre 0,2 – 130 keV µm-1).La finalité de cette étude serait de prédire les quantités de H2O2 et de HNO2 formés par radiolyse de HNO3/NaNO3 dans les étapes du procédé de retraitement des combustibles nucléaires. / Nitric acid is widely used in spent nuclear fuel reprocessing, especially in PUREX process (Plutonium and Uranium Refining by Extraction). This process is based on liquid-liquid extraction of Uranium (+VI) and Plutonium (+IV). Plutonium is separated from Uranium by addition of Uranium (+IV) in nitric acid, stabilized by hydrazinium ion (N2H5+). However, the radiolysis of nitric acid, result of the presence of alpha emitting radionuclides, generates in solutions free radicals and molecular species. These species are capable of modifying the redox state of actinides and reacting with hydrazinium ions.The aim of this work is to reveal the chemical and physical-chemical parameters that may modify the oxidation states of Uranium and Plutonium in nitric acid solutions. Among these parameters, the role of nitrous acid and hydrogen peroxide, generated by radiolysis of the nitric acid, is very important. The objective is to redefine the kinetics of formation of hydrogen peroxide and nitrous acid during alpha radiolysis of nitric acid / sodium nitrate, as a function of three parameters: acidity, nitrate concentration and the linear energy transfer of ionizing radiation.It was shown that the formation of hydrogen peroxide decreases with increasing nitrate ions concentration and increases greatly with the acidity of the solution (until it reaches a stationary value for an acidity of 0.2 mol L-1). The formation of nitrous acid is promoted by the increase the nitrate ions concentration. It was observed that G(HNO2) varies according to two trends. The first one in dilute nitrate solutions and the second in concentrated nitrate solutions. These two trends reflect the direct and indirect radiolytic phenomena, modifying the mechanisms of formation of HNO2. The study of acidity has showed that the formation of H2O2 and HNO2 is promoted by increasing the concentration of hydronium ions, until it reaches a steady state value for an acidity close to 0.2-0.5 mol L-1.Furthermore, the effects induced by ionizing radiation (,,,…) on formation yields of H2O2 and HNO2 were studied. It has been shown that the linear energy transfer (LET), between 0.2 keV µm-1 (characteristic of a gamma radiation) and 130 keV µm-1 (characteristic of the alpha radiation emitted by radioactive decay of actinides), has a significant influence on formation yield of H2O2 and HNO2. It was observed that the impact of nitrate ions on the formation yield of H2O2 becomes more pronounced when the LET increases. Conversely, the impact of nitrate ions which promote the formation of HNO2, decreases when the LET increases.Based on these results, two parametric equations were developed. The advantage of this parameterization is to predict the radiolytic yields formation of H2O2 and HNO2 according to chemical conditions ([NO3-] ≤ 4 mol L-1 and 10-5 mol L-1 ≤ [H+] ≤ 4 mol L-1) and the nature of the beam (LET between 0.2 to 130 keV µm-1).The purpose of this study is to predict the quantity of H2O2 and HNO2 formed by radiolysis of HNO3/NaNO3, during the different steps of the nuclear fuel reprocessing.