L’objectif principal de ce travail de thèse est de synthétiser par polymérisation RAFT en milieux homogène et hétérogène des copolymères à blocs amphiphiles de structure bien contrôlée. Un procédé simplifié, « ont pot » a donc été développé pour synthétiser ces copolymères et les auto-assembler en particules dans l’eau. Cette méthode dite de « l’auto-assemblage induit par la polymérisation » (PISA) permet de synthétiser en quantité des copolymères à blocs amphiphiles en milieux aqueux sans aucune étape de purification intermédiaire. Dans ce procédé, deux étapes successives sont effectuées dans le même réacteur. La 1ère étape a pour but de synthétiser des agents RAFT macromoléculaires hydrophiles (macroRAFTs) par polymérisation en solution dans l’eau. Ces macroRAFTs fonctionnalisés par un groupement trithiocarbonate sont ensuite utilisés dans le même réacteur comme agents de contrôle etprécurseurs de stabilisants pour la polymérisation en émulsion du monomère hydrophobe directement dans l’eau. Lors de cette 2nde étape, des copolymères à blocs amphiphiles sont formés et s’auto-assemblent sous forme de particules aux morphologies variées (sphères, filaments et vésicules). Nous avons alors étudiés les différents paramètres (pH, température de polymérisation en émulsion, nature des monomères hydrophobe et hydrophile, taux de solide, masses molaires des blocs hydrophobe et hydrophile, etc)gouvernant la formation de morphologies spécifiques. Un objectif supplémentaire a été l’étude du comportement viscoélastique linéaire des suspensions de ces nano-fibres polymère à une température inférieure (25°C) ou supérieure (130°C) à la température de transition vitreuse (Tg) du coeur polystyrène des nano-fibres. A T < Tg, les nano-fibres sont parfaitement rigides et obéissent à une dynamique brownienne de bâtonnets. En effet, les lois d’échelles déduites du comportement viscoélastique de ces suspensions obéissent aux lois prédites par Doi-Edwards. En revanche, ces nano-fibres sont flexibles pour T > Tg et ont une dynamique Brownienne de chaînes polymères en solution. / The aim of this work was synthesis of well-defined amphiphilic block copolymers in homogenous and heterogenous media using RAFT polymerization (Reversible Addition-Fragmentation Chain Transfer) and to study their self-assemblies in water. A one-pot process in water was developed for the synthesis of amphiphilic block copolymers that simultaneously to their growth self-assembled into nano-particles. This method called “polymerization-induced self-assembly” (PISA) allows the synthesis of large quantities of amphiphilic block copolymers in aqueous media without any intermediate purification step. During this process, two successive polymerization steps are performed in the same reactor. The first step consists in the synthesis of the hydrophilic macromolecular RAFT agents (macroRAFT agents) possessing a trithiocarbonate reactive group via RAFT in water. Without purification, these macroRAFT agents are reactivated for the polymerization of a hydrophobic monomer in the same reactor via RAFT emulsion polymerization. The resulting amphiphilic block copolymers self-assembled into nano-objects with various morphologies (spherical micelles, nanofibers and vesicles). Different parameters (pH, temperature, natureof hydrophilic and hydrophobic monomers, solids contents, molar masse of hydrophilic and hydrophobic blocks, etc) control these morphologies. Besides, the viscoelastic properties of polymeric nanofibers suspensions were studied as a function of the temperature. Below the Tg of polystyrene core at 25°C, the scaling law from viscoelastic behavior of these nanofiber suspensions the Doi−Edwards theory on the Brownian dynamics of rigid rods. Above Tg at 130°C, the nanofibers are flexible and it observed that their dynamics obey the power laws for polymer chains in solution.

Pupils' difficulties in solving selected word problems from TIMSS research. (Diploma Thesis.) Abstract The theoretical part of the diploma thesis describes international comparative surveys, namely PISA and TIMSS, and analyses results of Czech pupils. Some areas are distinguished in which our pupils were unsuccessful and from them, the area of word problems and their mathematisation was selected for further work. Next, a solving strategy is characterised and some relevant research from this area is given. The core of the work lies in the experimental part whose goal was to find out what strategies pupils use when solving selected problems from TIMSS research and why they fail in them, via the analysis of pupils' written solutions complemented by interviews with them. Causes of failure of our pupils in these problems in TIMSS 2007 are looked for in mistakes pupils make, while it is also followed in what phase of the solving process they appear. The participants of research were pupils of Grade 9 of a primary school who solved three selected word problems from TIMSS research. Their written solutions were complemented by interviews with the experimenter focused on their mistakes and lack of clarity of the solutions. Four pupils participated in a pilot study. The atomic analysis of their solutions confirmed...

Cette thèse est centrée sur les délibérations du tribunal de la Mercanzia de Florence. Pour les Florentins, l’accès au port de Pise, dont il est indirectement possible de reconstituer le trafic, est crucial et transcende les relations compliquées entre les deux villes. Mais, s’ils sont prêts à quitter Pise (1356-1369 et 1399-1406) ou à déclencher des guerres (1362-1364 et 1397-1398) pour défendre leurs exemptions de droits de douanes et de gabelles, leur analyse précise prouve la faible incidence sur les prix de vente. Ces sommes sont en réalité transférées à la nation florentine, dont la direction est bicéphale (un consul pisan, un notaire-syndic florentin). La découverte d’un statut de la nation (1381) permet de mieux connaître le rôle des dirigeants et la conservation d’un livre de compte (1374-1382) éclaire leur rémunération. Les structures communautaires sont centrées sur le fondaco de Porto Pisano, géré par la commune pisane, et sur la loggia, située dans le palais du seigneur de Pise de 1369 à 1392, ou 1395, date à laquelle la nation est transférée à Livourne et Piombino. Une double certification de la citoyenneté, par le serment de deux marchands et par l’envoi de lettres de la Mercanzia, est également mise en place. Les listes des traités bilatéraux ne recensent que les compagnies habilitées à prêter serment, ce qui rend difficile la prosopographie de la communauté. Le dernier chapitre montre la formation d’un champ judiciaire commun, capable de fonctionner durant les périodes de tension, à travers l’examen des procédures et du règlement de conflits concernant les franchises de taxes, le règlement des faillites et l’application du droit de représailles. / This PhD thesis focuses on the Deliberazioni of the Florentine court called Mercanzia. Access to the port of Pisa, the traffic of which can indirectly be reconstructed, is essential for Florentine people and transcends the difficult relationships between both cities. They are ready to leave Pisa (1356-1369 and 1399-1406) or to go to war (1362-1364 and 1397-1398) to defend their tax and customs exemptions, but an analysis of the specifics shows a weak impact on prices. These sums are transferred to two-headed Florentine natio (one Pisan consul, one Florentine notary-sindaco). The discovery of the natio’s statute (1381) improves our knowledge of the managers’ duties and the remaining accounts shows how they are paid. The structures of the community are concentrated on the fondaco of Porto Pisano, which is administrated by the Pisan city-state (commune), and on the loggia, located in the Pietro Gambacorta’s palace in Pisa from 1369 to 1392, or 1395, the year when the natio was transferred to Livorno and Piombino. Double certification of citizenship, first by an oath sworn by two merchants, second by the sending of letters by the Mercanzia, does exist. Lists in bilateral treaties only register the companies, whose members are able to declare one’s citizenship under oath, which makes the prosopography of the community even more difficult. The last chapter analyses the formation of a common judiciary field, able to function in times of strained relationship, through the presentation of bilateral procedures and of cases of conflict about tax exemptions, bankruptcy and reprisals.

The significance of this dissertation research is twofold with both methodological advancement and empirical update. In this dissertation research, quantile regression (QR) was introduced to social sciences researchers as a response to the weaknesses of the traditional mean-based regression often referred to as multiple regression. General advantages of QR includes being more flexible for modeling data with heterogeneous conditional distributions, more robust to outliers, and having richer characterization and description of the data. Results of QR allow researchers to not only describe a general trend of changes in the effects of the independent variables across a continuous distribution of the dependent variable but also provide information on characteristics of any shift in the distribution caused by the independent variables. These shifts pertain to location, scale, and shape shifts. This dissertation research reviewed graphical ways to examine location, scale, and shape shifts, and more importantly, developed statistical ways to quantify location, scale, and shape shifts (i.e., test for statistical significance of location, scale, and shape shifts). Overall, this dissertation demonstrated that the introduction of QR as an advanced statistical procedure will advance the quantitative landscape of social sciences research. The results of this dissertation showed that QR can detect the differential effects of independent variables on the dependent variables that mean-based regression cannot detect and therefore uncovers more detailed relationships. This quality of QR enables more in-depth research than mean-based regression in many fields. The results of this dissertation also showed that QR allows for the understanding of relationships between variables outside the mean of the data, making it useful in understanding outcomes that are non-normally distributed and that have non-linear relationships with the independent variables. Finally, this dissertation introduced ways to detect and describe distributional shifts caused by the independent variables. The median regression line describes the (central) location shift. In addition to the estimated location shifts, the other QR lines provide information about the scale and shape shifts. This dissertation developed the bootstrapping approach to test for statistical significance when comparing location, scale, and shape shifts between parameters within and between samples (i.e., studies). This dissertation research applied QR to the examination of individual differences in mathematics achievement and mathematics self-efficacy, using the 2003 and 2012 Programme for International Student Assessment (PISA) data. The QR results showed that the effects of many student characteristics were not constant across the mathematics outcomes distributions (i.e., mathematics achievement and mathematics self-efficacy). This suggested that individual differences were valued heterogeneously across the mathematics outcomes distributions. There was only one statistically significant location shift in terms of individual differences associated with family structure in both mathematics achievement and mathematics self-efficacy between 2003 and 2012. There was only one statistically significant scale shift in terms of individual differences associated with father SES in mathematics achievement for the middle 40 percent of the students between 2003 and 2012. There was only one statistically significant scale shift in terms of individual differences associated with gender in mathematics self-efficacy for the middle 40 percent of the students between 2003 and 2012. There was only one statistically significant shape shift in terms of individual differences associated with gender in mathematics self-efficacy between 2003 and 2012. Even though QR and LMR results can be similar in terms of statistical significance, they can differ dramatically in magnitude. Students’ age, gender, and socioeconomic status were typical examples in this study. The effect of student age generally became more positive as student mathematics achievement increased in 2003. This suggests that age had a stronger effect on better-performing students than lower-performing students in 2003. It also means that there are more age differences in the upper tail of student mathematics achievement distribution than in the lower tail.

English language learner (ELL) is a term to describe students who are still acquiring English proficiency. In recent decades, ELLs are a very rapidly growing student group in United States. In school classrooms, ELLs are learning English and their academic subjects simultaneously. It is challenging for them to hear lectures, read textbooks, and complete tests in English despite of their inadequate English language proficiency (Ilich, 2013). As a result, the increasing number of ELLs in public schools has paralleled the increase in ELLs’ low mathematics performance (NCES, 2016). Due to the popularization of international large-scale assessments in the recent decade, it is necessary to analyze their psychometric properties (e.g., reliability, validity) so that those results can provide with evidence-based implications for policymakers. Educational researchers need to assess the validity for subgroups within each country. The Programme for International Student Assessment (PISA), as one of the influential large-scale assessments, allows researchers to investigate academic achievement and group membership from a variety of different viewpoints. The current study was to understand the nature and potential sources of the gaps in mathematics achievement between ELLs and non-ELLs. The nature of achievement gap was examined using three DIF methodologies including Mantel-Haenszel procedure, Rasch analysis, and Hierarchical Generalized Linear Model (HGLM) at the item level instead of total test level. Amon the three methods, HGLM was utilized to examine the potential sources of DIF. This method can take into account of the nested structure of data where items are nested within students, and students nested within schools. At the student level, sources of DIF were investigated through students’ variations in mathematics self-efficacy, language proficiency, and student socioeconomic status. At the school level, school type and school educational resource were investigated as potential sources of DIF after controlling for the student variables. The U.S. sample from PISA 2012 was used, and 76 dichotomously coded items from PISA 2012 mathematics assessment were included to detect DIF effects. Results revealed that ten common items are identified with DIF effects using MH procedure, Rasch analysis, and HGLM. These ten items are all in favor of non-ELLs.The decreasing number of items showing DIF effects in HGLM after controlling for student-level variables revealed mathematics self-efficacy, language proficiency, and SES are potential sources of DIF between ELLs and non-ELLs. In addition, the number of DIF items continued to decrease after controlling for both student and school-level variables. This finding proved that school type and school educational resources were also potential sources of DIF between ELLs and non-ELLs. Findings from this study can help educational researchers, administrators, and policymakers understand the nature of the gap at item level instead of the total test level so that United States can be competitive in middle school mathematics education. This study can also help guide item writers and test developers in the construction of more linguistically accessible assessments for students who are still learning English. The significance of this study lies in the empirical investigation of the gap between ELLs and non-ELLs in mathematics achievement at an item level and from perspectives of both students and schools.

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The purpose of this study was to investigate the problem solving strategies, problem solving episodes, and metacognition of five Turkish students just graduated from elementary school and explore the interplay of these factors on their problem solving success in mathematics. The research data had been collected by clinical interviews and a self monitoring questionnaire followed by the interviews. Ten mathematical problems that participant students had worked on were selected among the released mathematical literacy items used in Programme for International Student Assessment (PISA) 2003. The problem solving strategies used by participants were coded according to the descriptions given by Posamentier &amp / Krulik (1999). The cognitive-metacognitive problem solving framework developed by Artzt and Armour-Thomas (1992) has been used to observe the problem solving episodes of the participants. The coding system developed by Pappas et al. (2003) has been utilized to examine the major components of metacognition (mistake recognition, adaptability, awareness and expression of thought) of the participants. The self-monitoring questionnaire responses were analyzed to crosscheck the results obtained from the clinical interviews. The problem solving behaviors of the participants observed in the study confirmed their academic success levels. The study confirmed that the problem solving success is too complex to be clarified by a unique property or a behavior of the problem solver. The problem solving requires overcoming various obstacles to reach a successful result. Hence, not only the students should have the required mathematical knowledge and a good repertoire of different problem solving strategies, but also they should know when and how to use those strategies, and also they could monitor and regulate their problem solving processes using their metacognitive skills. So mathematics teachers should provide problems that require different problem solving strategies and encourage the students to explore new strategies, to take risks in trying and to discuss failures and successes with peers and teacher.

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Este trabajo hace uso de datos suministrados por el Programa Internacional de Evaluación de Alumnos (PISA) con el objetivo de proveer una cuantificación de los niveles y la evolución de la segregación escolar por nivel socioeconómico en el mundo y contribuir a la discusión de sus determinantes. Los resultados sugieren un ranking de países que muestra a América Latina como una región de alta segregación escolar en términos relativos y donde la segregación entre escuelas públicas y privadas es relevante. Se encuentra además que la segregación escolar por nivel socioeconómico es mayor en aquellos países y períodos de tiempo en los que la desigualdad y la participación del sector privado en la matrícula es mayor, en tanto ciertos patrones de localización geográfica pueden también jugar un rol importante. / Este trabajo de tesis recibió una Mención Especial en el Concurso Investigador Joven 2011 de la Asociación Argentina de Economía Política.

The purpose was to investigate the relationship between Canadian and Saskatchewan PISA 2009 reading performance and organizational learning (OL) conditions as perceived by students and principals when selected student and school characteristics were taken into consideration. Gender, Aboriginal status, and socioeconomic status were the student characteristics that were considered. School size, urban versus rural school community, proportion of students self-identified as Aboriginal, and school average socioeconomic status were school characteristics taken into consideration. A nationally represented sample of 978 schools and 23,207 15-year-old students across the ten Canadian provinces participated in the PISA 2009. Within this sample, 1,997 students and 99 schools were from Saskatchewan. Principal components analyses were conducted to produce components for the calculation of two composite (OL) indices: a Student OL Index based on the Canada and OECD PISA student questionnaires and a School OL Index based on OECD PISA school questionnaire. Subsequently, two hierarchal linear modelling analyses were employed to examine the association of student-level OL index and school-level OL index with reading performance. Across Canadian and Saskatchewan schools, students’ perspective of OL conditions was positively associated with reading performance in the presence of the selected student and school characteristics. Except for one school-level OL component (i.e., principal’s perspective of school culture/environment) in the Canadian model, school-level OL conditions were not significantly associated to reading performance in the presence of student and school characteristics. With the adjustment of student and contextual characteristics incorporated in the modelling, the average reading performance was comparable across Canadian and Saskatchewan schools, 528 and 523 respectively. Variance decomposition of final models indicated that 55% of the Canadian school-level variance in reading achievement and 68% of the Saskatchewan school-level variance were explained by the selected student and school characteristics along with student perspective of OL conditions. The findings from this study supported the hypothesis that OL conditions are associated with student achievement. Additionally, it was noted that the effect of OL conditions was of similar magnitude to that of the socioeconomic status effect. Furthermore, the findings from this study further emphasized the importance of the student voice within the school OL framework.