published_or_final_version / abstract / Chemistry / Doctoral / Doctor of Philosophy

From a theoretical point of view, competition for the educational resources at the family and the population levels may change as the demographic transition advances. Although family size started to decline in the mid-1960s in México, the reduction in the size of the cohorts that compete for educational resources has recently occurred and it is an ongoing process in most municipalities of the country. Therefore, the main goal of this study was to examine the relationship between teenagers’ education and the demographic transition in México. The study explored if the teenagers’ school enrollment, age-grade delay at school and lower-secondary school attainment were linked to the teenagers’ number of siblings, as well as their cohort size in the municipality of residence in 2000. The 10% sample of the Mexican Housing and Population Census of 2000 was used as the main source of information. The study employed multivariate logistic regression models to accomplish its goals. Interactions between number of siblings and cohort size were tested. Also, interactions between these indicators and the teenagers’ gender and socioeconomic status were assessed respectively. The results indicated that contextual factors explained the initial negative association between teenagers’ education and cohort size, since this association disappeared or became small and positive after the addition of covariates. The Mexican educational system seems to have had the capacity of absorbing the demands in school coverage of the growing teenage population. The study revealed, however, that there was a large and negative association between teenagers’ education and number of siblings. Moreover, the study showed that the odds of the educational outcomes generally experienced larger changes by each additional sibling in the places where the demographic transition is more advanced, as well as among females and among the teenagers with high socioeconomic status. These results suggest that the educational disadvantages associated with multiple siblings may become more pronounced in the future and within certain contexts, as the demographic transition continues and big families become a smaller proportion of Mexican families. / text

As all couples experience stressful life events, understanding how couples adapt to stress is imperative for understanding marital development. Drawing from theories of stress inoculation, which suggest that the successful adaptation to mild stressors may help individuals develop a resilience to future stress, this project examined whether couples who have more experience effectively coping with minor stressors early in the marriage would be most resilient to declines in marital satisfaction when faced with future, larger stressors. Study 1 examined whether couples who enter marriage with good relationship skills and some experience coping with minor stressors exhibit the most stress resilience during the first two years of marriage. Study 2 examined whether couples who enter marriage with good skills and some experience with stress exhibit a greater resilience to the declines in marital satisfaction that often follow the transition to parenthood. Both studies revealed that spouses who have both good relationship skills and early stress experience exhibit better marital outcomes than spouses who have good skills, but little or no experience with stress. Thus, simply possessing good relationship skills may not be sufficient to shield marital satisfaction from stress. Rather, couples also may need practice applying those skills to minor stressors. / text

An atomically thin film of semiconducting transition metal dichalcogenides (TMDCs) is emerging as a class of key materials in chemistry and physics due to their remarkable chemical and electronic properties. The TMDCs are layered materials with weak out-of-plane van der Waals (vdW) interaction and strong in-plane covalent bonding enabling scalable exfoliation into two-dimensional (2D) layers of atomic thickness. The growth techniques to prepare these 2D TMDC materials in high yield and large scale with high crystallinity have attracted intensive attention recently because of the new properties and potentials in nano-elctronic, optoelectronic, spintronic and valleytronic applications. In this thesis, I develop methods for the chemical synthesis of 2D TMDCs films. The relevant growth mechanism and material characteristics of these films are also investigated. Molybdenum disulfide (MoS2) is synthesized by using molybdenum trioxide (MoO3) and sulfur (S) powder as the precursor. The films are formed on substrate pre-treated with reduced graphene oxide as the catalyst. However, this method cannot be extended to other TMDC materials such as molybdenum diselenide (MoSe2) and tungsten diselenide (WSe2) because reduced graphene oxide (rGO) reacts with selenium to form alloy materials rather than TMDC films. At the same time, the conversion of MoO3 to MoSe2 or that of tungsten trioxide (WO3) to WSe2 without the assistance of hydrogen in the chemical reaction is not thermodynamically feasible because the oxygen in the metal oxide cannot be replaced by selenium due to lower reactivity of the latter. On the other hand, I demonstrate that MoSe2 film can be synthesized directly by using MoSe2 and Se powder. Furthermore, the method of sulfurization or selenization of pre-deposited metal film can be promising due to precise thickness/size controls. Finally, some perspectives on the engineering challenges and fabrication methods of this family of materials will be given. / published_or_final_version / Physics / Master / Master of Philosophy

Les polymères semi-cristallins à chaînes semi-rigides, bien qu’abondamment utilisés dans la vie quotidienne, représentent des systèmes complexes qui ne sont pas encore parfaitement compris. Parmi les nombreux domaines de recherche sur cette famille de polymères, l’étude de la morphologie semi-cristalline et des processus de cristallisation et de fusion de ceux-ci restent des sujets très importants. L’investigation de la morphologie semi-cristalline est rendue difficile car elle présente une structure hiérarchique composée de plusieurs niveaux d’organisation, dont le plus petit est observable à une échelle très réduite de quelques nanomètres. De plus, les aspects liés à la cinétique des processus de cristallisation et de fusion n’ont pas toujours permis de bien les mettre en évidences, les rendant ainsi par très bien compris. Cependant, les nouvelles avancées technologiques dans le domaine de la physique expérimentales ont beaucoup profité à la science des polymères. Dans ce travail, une contribution originale est apportée à cette étude, et cela en combinant diverses techniques expérimentales permettant des mesures calorifiques et structurales en températures et temps réels. L’intérêt c’est porté sur les polymères linéaires aromatiques tels que le polyéthylènes teréphthalate, PET, et le polytriméthylène téréphthalate, PTT, caractérisés par une température de transition vitreuse supérieure à l’ambiante ( Tg > 50°) et une température de fusion élevée (Tm>220°C), offrant ainsi une assez large gamme de température de cristallisation (Tm-Tg). L’étude de la structure semi-cristalline du PET à l’échelle du nanomètre et de la relaxation des phases amorphes présentes dans sa structure est facilitée par l’utilisation d’un diluant amorphe tel que le polyétherimide (PEI), qui forme un mélange miscible avec le PET. L’utilisation de microscopie de force atomique AFM à haute température a permis d’observer la cristallisation isotherme de PET en temps réel et de décrire ainsi la cristallisation secondaire comme un processus d'épaississement des piles lamellaires. De plus, l’analyse de la structure semi-cristalline du PET et du PTT, dans l’espace direct, sont en faveur d’un modèle structural homogène, où l’épaisseur lamellaire moyenne est légèrement inférieure à l’épaisseur moyenne des régions amorphes interlamellaires. Ces résultats ont permis, d’une part, d’apporter une meilleure interprétation aux données obtenues par diffusion des rayons X aux petits angles (SAXS), et d’autre part, d’ interpréter le comportement de fusion multiple caractéristique des polymères semi-cristallin à chaînes semi-rigides par le seul processus de fusion-recristallisation. Dans l’étude investiguée sur les mélanges PET/PEI et sur le PTT pur, on montre que la cinétique d’un tel processus est particulièrement rapide comparée à la cristallisation. De plus, les observations par AFM et par microscopie optique de même que les mesures SAXS en temps réel ont montré la simultanéité et la compétition existant entre la fusion des cristaux et leur réorganisation durant la chauffe. Par ailleurs, la relaxation des régions amorphes interlamellaires, souvent considérées comme rigides, a pu être mise en évidence par les mesures AFM et SAXS réalisées à haute température sur des échantillons de PET/PEI semi-cristallins.

<p>Det svenska biståndet inriktat mot demokratisering uppgick 2008 till ca 4 miljarder kr. Det civila samhällets roll i demokratiseringsprocesser har fått ökad uppmärksamhet de senaste 15 åren och är numera ett av de vanligaste fokusområdena inom demokratibistånd. Syftet med denna uppsats är att undersöka det svenska demokratibiståndet inriktat på det civila samhället och dess effekter och dess möjligheter att påverka demokratiseringsprocesser Genom att undersöka utvärderingar av olika projekt, vars syfte varit att stärka det civila samhället, har biståndets egentliga effekter kunnat redovisas. De länder som undersöks i denna uppsats är Moldavien, Etiopien, Zimbabwe och fyra län-der i Latinamerika; Bolivia, Guatemala, Peru, Nicaragua. De resultat som redovisas i upp-satsen ligger först och främst i attityd- och beteendeförändringar på individnivå hos de som varit inblandade i organisationer, men även bland vanliga medborgare. Människor har blivit mer medvetna om deras politiska och civila rättigheter. I vissa fall har även förändringar skett främst på lokalnivå, där kommunalpolitiker blivit mindre rädda för det civila samhäl-let, och dialoger kunnat föras och där organisationer och vanliga medborgare vågat ställa krav på vissa av deras rättigheter. På detta plan har biståndet alltså kunnat påverka det civila samhället.Vad som dock utgör ett hinder för det civila samhällets möjligheter att påverka på nationell nivå är den bristande respekt som de statliga institutionerna visar. För att det civila samhäl-let ska kunna påverka beslut och öka demokratin i de länder som undersöks behöver en ömsedig respekt utvecklas mellan staten och det civila samhället.</p> / <p>The Swedish aid focused on democratization amounted to approximately 4 billion SEK in 2008. The role of civil society in democratization processes have received increased atten-tion in the last 15 years and is now one of the most common focus areas of democracy as-sistance. The aim of this thesis is to examine the Swedish democracy assistance focused on civil society and its effects and its ability to influence the processes of democratization. By examining evaluations of different projects, which aim was to strengthen civil society, the actual effects have been possible to show.The countries examined in this thesis is Moldova, Ethiopia, Zimbabwe and four countries in Latin America, Bolivia, Guatemala, Peru, Nicaragua. The results shown in the thesis is primarily in attitude and behavior change at the individual level among those who have been involved in organizations, but also among ordinary citizens. People have become more aware of their political and civil rights. In some cases, even changes primarily at the local level, where local politicians have become less fearful of civil society, and dialogue, and where organizations and ordinary citizens dared to make demands on some of their rights. On this level, the aid has been able to influence civil society.What, however, is an obstacle to civil society's ability to influence at the national level is the lack of respect which the state institutions show. For civil society to be able to influence decisions and increase democracy in the countries under study there need to be a reciprocal respect developed between the state and civil society.</p>

No description available.

No description available.

No description available.

No description available.