Student Number: 0004062T Doctor of Philosophy Faculty of Humanities and Social Sciences / This thesis discusses the impact that the Ford, Mott, Kellogg and Open Society Foundations had on civil society organisations in South Africa in setting development priorities. The thesis tested first, the hypothesis that donors set the agenda for their grantees. Secondly, the thesis tested the assumption that aid facilitates grantees’ submission to donor interests. And in the process grantees lose their identity and focus. The research found that most of civil society organisations (CSOs) depended on international donors, in particular, foundations,for their operations. There was little mobilisation of resources from local citizens. As a result, CSOs were vulnerable to donor conditionalities and agendas. The four case studies and their selected beneficiaries show that most CSOs were not sustainable. If donors withdrew their support, a number of their grantees would curtail their work, close down or lose their vision and mission. In some cases CSOs changed their missions to follow the money, nevertheless, changing contexts and demands were also relevant factors. Although lack of sustainability for CSOs and their greater dependency on international donors made their agendas questionable, it also provided independence from internal political interference. CSOs also appeared more accountable to donors than to the constituencies they served. The Kellogg Foundation insisted that organisations had to toe the line to implement the Foundation’s agenda or risk losing funding. George Soros of the Open Society Foundation also called the shots. He set the agenda and his Foundations implemented it. This showed the power of direct intervention by a living donor who operated as a Programme Officer for all his foundations. The question of donor-dependency is closely linked to that of leadership. A number of organisations with good leaders attracted many donors. However the increase in donors, did not sustain these organisations, instead it made them vulnerable to many different donor demands. Thus, donor diversification was both an asset and a threat. However, good leadership prevented CSOs from collapse from lack of transparency, accountability and effectiveness. A temptation to ‘want to look like donors’, a process that is called ‘isomorphism’ by DiMaggio and Powell (1991) characterised many CSOs resulting in them losing their identity, mission and vision. There were positive aspects that international Foundations achieved in supporting civil society foundations. The Open Society Foundation worked to open up closed societies. It supported efforts that aimed at fostering democratic ideals, rule of law, social justice and open societies. The Ford Foundation supported efforts that strengthened civil society, promoted social justice and democracy. The Mott Foundation strengthened the capacity of the non-profit sector by developing in-country philanthropy. And the Kellogg Foundation supported community initiatives that aimed to tackle the causes of poverty. A negative development; however was that Foundations cultivated the culture of receiving rather than giving among their grantees. For this reason, the thesis suggested the development of ‘community philanthropy’ to sustain the non-profit (NPO) sector. Community philanthropy has the advantage of mobilising resources from domestic sources and taping into levels of social capital. Building on domestic sources would encourage a bottom up approach to development. I argue that local self-help initiatives such as stokvels, burial societies and saving clubs could serve as bases for the sustainability of the non-profit sector which suffered from donor dependency, unsustainability and poor leadership. Such an approach would make development ‘people-centered’ and encourage social responsibility among citizens to support their NPOs and its development initiatives.

This thesis covers most of my work in the field of ultracold atoms loaded in optical lattices. This thesis can be divided into five different parts. In Chapter 1, after a brief introduction to the field of optical lattices I review the fundamental aspects pertaining to the physics of systems in periodic potentials and a short overview of the experiments on ultracold atoms in an optical lattice. In Chapter 2 we develop an inhomogeneous mean-field theory for the extended Bose-Hubbard model with a quadratic, confining potential. In the absence of this poten¬tial, our mean-field theory yields the phase diagram of the homogeneous extended Bose-Hubbard model. This phase diagram shows a superfluid (SF) phase and lobes of Mott-insulator(MI), density-wave(DW), and supersolid (SS) phases in the plane of the chemical potential and on-site repulsion ; we present phase diagrams for representative values of , the repulsive energy for bosons on nearest-neighbor sites. We demonstrate that, when the confining potential is present, superfluid and density-wave order parameters are nonuniform; in particular, we obtain, for a few representative values of parameters, spherical shells of SF, MI ,DW ,and SSphases. We explore the implications of our study for experiments on cold-atom dipolar con¬densates in optical lattices in a confining potential. In Chapter3 we present an extensive study of Mottinsulator( MI) and superfluid (SF) shells in Bose-Hubbard (BH) models for bosons in optical lattices with har¬monic traps. For this we develop an inhomogeneous mean-field theory. Our results for the BH model with one type of spinless bosons agrees quantitatively with quan¬tum Monte Carlo(QMC) simulations. Our approach is numerically less intensive than such simulations, so we are able to perform calculations on experimentally realistic, large three-dimensional(3D) systems, explore a wide range of parameter values, and make direct contact with a variety of experimental measurements. We also generalize our inhomogeneous mean-field theory to study BH models with har¬monic traps and(a) two species of bosons or(b) spin-1bosons. With two species of bosons we obtain rich phase diagrams with a variety of SF and MI phases and as¬sociated shells, when we include a quadratic confining potential. For the spin-1BH model we show, in a representative case, that the system can display alternating shells of polar SF and MI phases; and we make interesting predictions for experi¬ments in such systems. . In Chapter 4 we carry out an extensive study of the phase diagrams of the ex-tended Bose Hubbard model, with a mean filling of one boson per site, in one dimension by using the density matrix renormalization group and show that it contains Superfluid (SF), Mott-insulator (MI), density-wave (DW) and Haldane ¬insulator(HI) phases. We show that the critical exponents and central charge for the HI-DW,MI-HI and SF-MI transitions are consistent with those for models in the two-dimensional Ising, Gaussian, and Berezinskii-Kosterlitz-Thouless (BKT) uni¬versality classes, respectively; and we suggest that the SF-HI transition may be more exotic than a simple BKT transition. We show explicitly that different bound¬ary conditions lead to different phase diagrams.. In Chapter 5 we obtain the excitation spectra of the following three generalized of Bose-Hubbard(BH) models:(1) a two-species generalization of the spinless BH model, (2) a single-species, spin-1 BH model, and (3) the extended Bose-Hubbard model (EBH) for spinless interacting bosons of one species. In all the phases of these models we show how to obtain excitation spectra by using the random phase approximation (RPA). We compare the results of our work with earlier studies of related models and discuss implications for experiments.

Quantum spin liquids (QSLs) are strongly correlated systems displaying fascinating phenomena like long-range entanglement and fractionalized excitations. The research on these states has since its beginning followed trends generated by the synthesis of new compounds and the construction of new theoretical tools. In coherence with this history, a manifold of new results about QSLs were established during the past decade due to studies on the integrable Kitaev model on the honeycomb lattice. This j = 1/2 model displays bond-dependent and anisotropic exchanges that are essential to stabilize its QSL ground state with Majorana fermion excitations and emergent Z2 gauge field. Even more interestingly, this model is relevant to understand the magnetism of a certain class of 4/5d5 Mott insulators with specific lattice constraints, t2g orbital degeneracy and strong spin-orbit coupling (SOC). This mechanism defining these so-called Kitaev materials can be applied to similar compounds based on transition metal ions in different electronic configurations. In this thesis, I investigate minimal models for two types of 4/5d1 Mott insulators: the ones on the ordered double perovskite structure (ODP) and the ones isostructural to the Kitaev materials. Their effective models generically show bond-dependent and anisotropic interactions involving multipoles of an effective j = 3/2 angular momentum. Such degrees of freedom are conveniently written in terms of pseudospin s and pseudo-orbital τ operators resembling spin and orbital operators of Kugel-Khomskii models with twofold orbital degeneracy. Despite their anisotropy, the two realistic models display continuous global symmetries in the limit of vanishing Hund\'s coupling enhancing quantum fluctuations and possibly stabilizing a QSL phase. Parton mean-field theory was used to propose fermionic QSLs that will be called quantum spin-orbital liquids (QSOLs) due their dependence with s and τ. On ODPs, I studied a chiral QSOL with Majorana fermion excitations and a gapless spectrum characterized by nodal lines along the edges of the Brillouin zone. These nodal lines are topological defects of a non-Abelian Berry connection and the system exhibits dispersing surface states. Several experimental responses of the chiral QSOL within the mean-field approximation are compared with the experimental data available for the spin liquid candidate Ba2YMoO6. Moreover, based on a symmetry analysis, I discuss the operators involved in resonant inelastic X-ray scattering (RIXS) amplitudes for 4/5d1 Mott insulators and show that the RIXS cross sections allow one to selectively probe pseudospin and pseudo-orbital degrees of freedom. For the chiral spin-orbital liquid in particular, these cross sections provide information about the spectrum for different flavors of Majorana fermions. The model for materials isostructural to the Kitaev materials has an emergent SU(4) symmetry that is made explicit by means of a Klein transformation on pseudospin degrees of freedom. The model is known to stabilize a QSOL on the honeycomb lattice and instigated the investigation of QSOLs on a generalization of this lattice to three dimensions. Parton mean-field theory was used once again to propose the liquid states, and a variational Monte Carlo (VMC) method was used to compute the energies of the projected wave functions. The numerical results show that the lowest-energy QSOL corresponds to a zero-flux state with a Fermi surface of four-color fermionic partons. Further VMC computations also revealed that this state is stable against formation of plaquette ordering (tetramerization). The energy of this QSOL is highly competitive even when Hund\'s coupling induced perturbations are included, as shown by comparison with simple ordered states. Extensions and perspectives for future work are discussed in the end of this thesis. / Líquidos de spin quânticos (QSLs) são sistemas fortemente correlacionados que apresentam fenômenos fascinantes como emaranhamento de longo alcance e excitações fracionárias. A pesquisa a respeito destes estados seguiu tendências geradas pela síntese de novos compostos e construção de novas técnicas teóricas desde seu princípio. Coerentemente com essa história, uma variedade de novos resultados a respeito de líquidos de spin foram estabelecidos na última década graças a estudos feitos sobre o modelo integrável de Kitaev na rede colmeia. Este modelo de spins j = 1/2 apresenta interações de troca anisotrópicas e direcionalmente dependentes que são essenciais para estabilizar um estado fundamental do tipo QSL com férmions de Majorana e campo de gauge Z2 emergente. Ainda mais interessante, este modelo é relevante para se entender o magnetismo de uma certa classe de isolantes de Mott baseados em metais de transição na configuração 4/5d5 em redes específicas, degenerescência orbital t2g e acoplamento spin-órbita forte (SOC). Esse mecanismo que define os chamados materiais do tipo Kitaev podem ser aplicados a compostos baseados em metais de transição em configurações eletrônicas diferentes. Nesta tese, eu investigo modelos mínimos para dois tipos de isolantes de Mott do tipo 4/5d1: os que se apresentam na estrutura perovskita dupla ordenada (ODP) e os isostruturais aos materiais do tipo Kitaev. Seus modelos efetivos genericamente apresentam interações multipolares anisotrópicas e direcionalmente dependentes de um momento angular efetivo j = 3/2. Estes graus de liberdade são convenientemente escritos em termos de operadores de pseudospin s e pseudo-orbital τ semelhantes a operadores de spin e orbital de modelos do tipo Kugel-Khomskii com orbitais duplamente degenerados. A despeito da anisotropia, esses dois modelos realísticos apresentam simetrias globais contínuas no limite de acoplamento de Hund nulo que incrementam flutuações quânticas e possivelmente estabilizam uma fase do tipo QSL. A teoria de campo médio com partons foi usada para propor QSLs fermiônicos que serão chamados de líquidos spin-orbitais quânticos (QSOLs) devido à dependência deles com s e τ. Em ODPs, eu estudei um líquido de spin quiral com excitações do tipo férmion de Majorana e um espectro sem gap caracterizado por linhas nodais ao longo das arestas da zona de Brillouin. Essas linhas nodais são defeitos topológicos de uma conexão de Berry não-abeliana e o sistema apresenta estados de superfície dispersivos. Várias respostas experimentais foram calculadas para o QSOL quiral dentro da aproximação de campo médio e comparadas com os dados experimentais disponíveis para o candidato a líquido de spin Ba2YMoO6. Além disso, baseado em uma análise de simetria, discuto os operadores envolvidos nas amplitudes de espalhamento de raios-x ressonante para isolantes de Mott na configuração 4/5d1 e mostro que seções de choque de RIXS permitem estudar seletivamente os graus de liberdade de pseudospins e pseudo-orbitais. Para o caso particular do líquido spin-orbital quiral, essas seções de choque nos fornecem informações sobre o espectro de diferentes sabores de férmions de Majorana. Esse modelo possui uma simetria SU(4) emergente que é tornada explícita através de uma transformações de Klein nos graus de liberdade de pseudospin. Sabe-se que este modelo estabiliza um QSOL na rede colmeia, o que instigou uma investigação de QSOLs na generalização desta rede em três dimensões. A teoria de campo médio com partons foi usada novamente para propor estes líquidos quânticos, e o método de Monte Carlo Variacional (VMC) foi usado para calcular as energias das funções de onda projetadas. Os resultados numéricos mostraram que o QSOL de menor energia corresponde a um estado de fluxo-zero com superfície de Fermi envolvendo partons fermiônicos de quatro cores. Cálculos adicionais com VMC também demonstraram que este estado é estável à formação de ordem de plaquetas (tetramerização). A energia deste QSOL é altamente competitiva mesmo quando perturbações induzidas pelo acoplamento de Hund são incluídas, o que é mostrado através da comparação com estados ordenados simples. Extensões e perspectivas para trabalhos futuros são discutidas no final desta tese.

Le développement de la plaque bipolaire - PB -métallique nécessite une amélioration des propriétés du matériau qui la constitue. L'utilisation de l'acier implique une meilleure compréhension du film passif - FP. En effet, le cahier des charges de la PB demande une bonne conduction électronique ainsi qu'une longue durée de vie. L'amélioration de ces paramètres passe par une meilleure corrélation et compréhension entre les propriétés semi-conductrices et la résistance à la corrosion. La difficulté liée à l'étude de la passivation réside dans les nombreux phénomènes modifiant le comportement du film passif. De nombreux modèles présentés dans la littérature peuvent être utilisés pour caractériser la passivation. L'un des principaux, le Modèle de Défauts Ponctuels de D. D. Macdonald (Point Defect Model - PDM), décrit le FP à partir d'une série de réactions électrochimiques se déroulant à l'interface métal/oxyde et à l'interface oxyde/électrolyte. La réactivité est limitée par le transport de matière à travers l'oxyde. Après une étude bibliographique, ce phénomène semble être un paramètre discriminant dans le choix des modèles. Une méthode de sélection permettant une utilisation de chacun de ces modèles en fonction de leurs spécificités est proposée. Ainsi, cette méthode est basée sur la corrélation entre la mesure du transport de matière à partir des équations du PDM et l'analyse des Spectres d'Impédance Electrochimique (SIE). Le PDM caractérisant le transport de matière indépendamment de la SIE, il devient possible de déterminer le bien-fondé de la prise en compte de celui-ci dans les mesures de spectroscopie d'impédance électrochimique. L'évolution de la densité du porteur de charge majoritaire avec le potentiel de formation de l'oxyde permet d'accéder au coefficient de transport à partir des équations du PDM. Connaissant l'épaisseur de l'oxyde par des mesures XPS, la constante de temps et la fréquence caractéristique peuvent être déterminées. Sur la base de ces deux valeurs, un modèle descriptif d'analyse des spectres est sélectionné en évitant le sur-paramétrage. Cette méthode est appliquée d’abord à un matériau modèle, le chrome pur exposé à un milieu acide (pH 2), à différentes températures (30°C et 80°C). Elle valide la nécessité de la prise en compte du transport de matière à 80°C ainsi que la présence d'une surface composée d'une couche d'oxyde interne et d'une couche d'hydroxyde externe. Dans un second temps, cette méthode est utilisée sur un matériau industriel, un acier de type AISI 316L, à différents pH (1,2 et 3) et à différentes températures (30°C et 80°C). Elle a permis de décrire l'oxyde en surface comme une jonction p-n prenant en compte une couche riche en chrome interne avec un gradient de concentration de fer. Cette méthode a permis de caractériser de manière approfondie l'acier de type AISI 316L. Bien que ne concernant que le substrat, cette étape est déterminante dans l'amélioration des performances des PB métalliques. / Developments in metallic bipolar plate, to apply more widely fuel cells, require an improved of the constitutive material. The use of stainless steel calls for a good understanding of the passive film. The required specifications are for good electrical conductivity and a long life-time. Those two parameters correspond to a correlation between the semiconductive properties and the good corrosion behavior. Nevertheless, the main problems of the passivity lie on the multiplicity of the phenomena that alter the passive film behavior. Numerous models described in the literature can be used to characterize the passivation. The Point Defect Model (PDM) describes the passivation through electrochemical reactions at the metal / oxide and at the oxide / electrolyte interfaces. The reactivity is limited by mass transport through the oxide. From the literature, those phenomena seems to be a discriminating parameter in the choice of a model. The selective method proposed allows us to use each model taking into account their specifics. This methodology is based on the correlation between the mass transport characterization, thanks to the PDM, and the analysis of the Electrochemical Impedance Spectroscopy (EIS). The PDM determines the transport coefficient apart from EIS measurements, so to validate the consideration of the mass transport during the analysis of the electrochemical impedance spectra. The evolution of the main charge carrier density as a function of the oxide formation potential allows us to calculate the transport coefficient from PDM equations. Thanks to the thickness of the oxide (determined by X-ray Photoelectron Spectroscopy), the time constant of the mass transport is determined. Based on this value, a descriptive model is used to analyze the EIS data, avoiding overparametrization. This method is applied first on a model material, pure chromium exposed to acidic solution (pH 2) at several temperatures (30°C and 80°C). It shows that the mass transport has to be taken into account at 80°C and the EIS model considers an inner chromium oxide layer and an outer chromium hydroxide. Secondly, the method is used to characterize an industrial material, AISI 316L stainless steel, at several pH (1, 2 and 3) and at several temperatures (30°C and 80°C). In this case, the oxide is describe as a p-n semiconductor junction with an chromium rich inner layer and an outer iron rich layer. The present methodology permits to deeply characterize the AISI 316L stainless steel. Even if this study concerns the substrate, this step is decisive to improve the performances of the metallic bipolar plates

A trial was conducted to evaluate forage production potential, forage intake and milk production in two perennial tropical grasses under continuous grazing of lactating cows, in the growth seasons of 2003/04 and 2004/05, in Palmeira das Missões/RS. Twelve tester animaIs were distributed in two paddocks per treatment, using "put-and-take" technique to adjust stocking rates. Evaluated treatments were Dwarf Elephantgrass (Pennisetum purpureum cv. Mott) and Tifton 85 (Cynodon dactylon x C. nlemfuensis) pastures. Under the proposed management criteria (4 % of leaf lamina allowance), Tifton 85 demonstrates to be less sensible to forage production and stocking rate reduction under adverse climate conditions, with relative stability of forage mass available. Its superiority in individual animal performance, in more favourable conditions (2003/04 growth season), when compared to Dwarf Elephantgrass, should be related to the allowance used. Maintaining low levels of leaf lamina on offer could be limiting to cows' individual performance, rebounding negatively over persistency of the pastures. The evaluated species presented different structures and forage densities in the most accessible strata to grazing by the animaIs. However, those differences didn't affect the chemical composition of these layers nor of its respective of its respective "hand-plucking" samples, causing similar forage intake. Higher individual animal production indices were found, indicating a little known potential for perennial tropical grasses in milk from pasture systems. / Para avaliar o potencial forrageiro, o consumo de forragem e a produção de leite em duas gramíneas perenes tropicais sob pastejo contínuo de vacas em lactação, foi conduzido um experimento nos anos agrícolas de 2003/04 e 2004/05, em Palmeira das Missões/RS. Foram utilizados 12 animais testes, distribuídos em dois piquetes por tratamento, adotando-se a técnica dos animais reguladores para ajustes da carga animal. Os tratamentos avaliados foram pastagens de Capim Elefante Anão (Pennisetum purpureum cv. Mott) e Tifton 85 (Cynodon dactylon x C. nlemfuensis). Sob o critério de manejo proposto (oferta de 4 % de lâminas foliares), o Tifton 85 demonstra ser menos sensível à redução da produção forrageira e capacidade de carga sob condições adversas de clima, com relativa manutenção da massa de forragem disponível. Sua superioridade em produção individual por animal, em condições mais favoráveis (ano agrícola 2003/04), quando comparado ao Capim Elefante Anão, deve estar relacionada à oferta utilizada. A manutenção de níveis reduzidos de oferta de lâminas foliares pode ter sido limitante ao desempenho individual das vacas, repercutindo também de forma negativa na persistência produtiva das pastagens. As espécies estudadas apresentaram distintas estruturas e densidades de forragem nos estratos mais acessíveis ao pastejo pelos animais. Contudo, tais diferenças estruturais não afetaram a composição química destas camadas ou das respectivas simulações de pastejo, acarretando em consumo de forragem similar. Foram registrados elevados índices de produção animal individual, indicando um potencial pouco conhecido das gramíneas tropicais em sistemas de produção de leite a pasto.

Made available in DSpace on 2014-12-17T15:15:02Z (GMT). No. of bitstreams: 1 FabioFM.pdf: 1459636 bytes, checksum: 4f2bb557c6a5bddb80e46f325bd5b4dd (MD5) Previous issue date: 2004-12-03 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / In this work we study the spectrum (bulk and surface modes) of exciton-polaritons in infinite and semi-infinite binary superlattices (such as, ???ABABA???), where the semiconductor medium (A), whose dielectric function depends on the frequency and the wavevector, alternating with a standard dielectric medium B. Here the medium A will be modeled by a nitride III-V semiconductor whose main characteristic is a wide-direct energy gap Eg. In particular, we consider the numerical values of gallium nitride (GaN) with a crystal structure wurtzite type. The transfer-matrix formalism is used to find the exciton-polariton dispersion relation. The results are obtained for both s (TE mode: transverse electric) and p (TM mode: transverse magnetic) polarizations, using three diferent kind of additional boundary conditions (ABC1, 2 e 3) besides the standard Maxwell's boundary conditions. Moreover, we investigate the behavior of the exciton-polariton modes for diferent ratios of the thickness of the two alternating materials forming the superlattice. The spectrums shows a confinement of the exciton-polariton modes due to the geometry of the superlattice. The method of Attenuated Total Reflection (ATR) and Raman scattering are the most adequate for probing this excitations / Neste trabalho estudamos o espectro (modos de volume e de superf?cie) dos polaritons de exciton em uma super-rede bin?ria infinita e semi-infinita (tal como, ???ABABA???), onde um meio semicondutor (A), cuja fun??o diel?trica depende da frequ?ncia e do vetor de onda, alterna-se com um diel?trico comum (B). Aqui, o meio A ser? modelado por um semicondutor da fam?lia dos nitretos (semicondutor III-V) que tem como caracter?stica principal um gap de energia (Eg) direto e largo. Em particular, consideramos os valores num?ricos para o nitreto de g?lio (GaN) com uma estrutura cristalina tipo wurtzite. A t?cnica da matriz de transfer?ncia ? utilizada para encontrarmos a rela??o de dispers?o do polariton de exciton. Os resultados s?o obtidos para os modos de polariza??o s (ou modo TE: transversal el?trico) e p (ou modo TM: transversal magn?tico), usando tr?s diferentes condi??es de contorno adicionais (ABC1, 2 e 3), mais as condi??es de contorno padr?es de Maxwell. Al?m disso, investigamos o comportamento dos modos do polariton de exciton para diferentes raz?es entre as espessuras das camadas dos dois materiais que comp?em a super-rede Os espectros encontrados evidenciam um comportamento de confinamento dos polaritons de exciton devido ?s geometrias empregadas. As t?cnicas experimentais ATR ("Attenuated Total Reflection") e o espalhamento Raman s?o as mais adequadas para a caracteriza??o dessas excita??es

Quantum spin liquids (QSLs) are strongly correlated systems displaying fascinating phenomena like long-range entanglement and fractionalized excitations. The research on these states has since its beginning followed trends generated by the synthesis of new compounds and the construction of new theoretical tools. In coherence with this history, a manifold of new results about QSLs were established during the past decade due to studies on the integrable Kitaev model on the honeycomb lattice. This j = 1/2 model displays bond-dependent and anisotropic exchanges that are essential to stabilize its QSL ground state with Majorana fermion excitations and emergent Z2 gauge field. Even more interestingly, this model is relevant to understand the magnetism of a certain class of 4/5d5 Mott insulators with specific lattice constraints, t2g orbital degeneracy and strong spin-orbit coupling (SOC). This mechanism defining these so-called Kitaev materials can be applied to similar compounds based on transition metal ions in different electronic configurations. In this thesis, I investigate minimal models for two types of 4/5d1 Mott insulators: the ones on the ordered double perovskite structure (ODP) and the ones isostructural to the Kitaev materials. Their effective models generically show bond-dependent and anisotropic interactions involving multipoles of an effective j = 3/2 angular momentum. Such degrees of freedom are conveniently written in terms of pseudospin s and pseudo-orbital τ operators resembling spin and orbital operators of Kugel-Khomskii models with twofold orbital degeneracy. Despite their anisotropy, the two realistic models display continuous global symmetries in the limit of vanishing Hund\'s coupling enhancing quantum fluctuations and possibly stabilizing a QSL phase. Parton mean-field theory was used to propose fermionic QSLs that will be called quantum spin-orbital liquids (QSOLs) due their dependence with s and τ. On ODPs, I studied a chiral QSOL with Majorana fermion excitations and a gapless spectrum characterized by nodal lines along the edges of the Brillouin zone. These nodal lines are topological defects of a non-Abelian Berry connection and the system exhibits dispersing surface states. Several experimental responses of the chiral QSOL within the mean-field approximation are compared with the experimental data available for the spin liquid candidate Ba2YMoO6. Moreover, based on a symmetry analysis, I discuss the operators involved in resonant inelastic X-ray scattering (RIXS) amplitudes for 4/5d1 Mott insulators and show that the RIXS cross sections allow one to selectively probe pseudospin and pseudo-orbital degrees of freedom. For the chiral spin-orbital liquid in particular, these cross sections provide information about the spectrum for different flavors of Majorana fermions. The model for materials isostructural to the Kitaev materials has an emergent SU(4) symmetry that is made explicit by means of a Klein transformation on pseudospin degrees of freedom. The model is known to stabilize a QSOL on the honeycomb lattice and instigated the investigation of QSOLs on a generalization of this lattice to three dimensions. Parton mean-field theory was used once again to propose the liquid states, and a variational Monte Carlo (VMC) method was used to compute the energies of the projected wave functions. The numerical results show that the lowest-energy QSOL corresponds to a zero-flux state with a Fermi surface of four-color fermionic partons. Further VMC computations also revealed that this state is stable against formation of plaquette ordering (tetramerization). The energy of this QSOL is highly competitive even when Hund\'s coupling induced perturbations are included, as shown by comparison with simple ordered states. Extensions and perspectives for future work are discussed in the end of this thesis. / Líquidos de spin quânticos (QSLs) são sistemas fortemente correlacionados que apresentam fenômenos fascinantes como emaranhamento de longo alcance e excitações fracionárias. A pesquisa a respeito destes estados seguiu tendências geradas pela síntese de novos compostos e construção de novas técnicas teóricas desde seu princípio. Coerentemente com essa história, uma variedade de novos resultados a respeito de líquidos de spin foram estabelecidos na última década graças a estudos feitos sobre o modelo integrável de Kitaev na rede colmeia. Este modelo de spins j = 1/2 apresenta interações de troca anisotrópicas e direcionalmente dependentes que são essenciais para estabilizar um estado fundamental do tipo QSL com férmions de Majorana e campo de gauge Z2 emergente. Ainda mais interessante, este modelo é relevante para se entender o magnetismo de uma certa classe de isolantes de Mott baseados em metais de transição na configuração 4/5d5 em redes específicas, degenerescência orbital t2g e acoplamento spin-órbita forte (SOC). Esse mecanismo que define os chamados materiais do tipo Kitaev podem ser aplicados a compostos baseados em metais de transição em configurações eletrônicas diferentes. Nesta tese, eu investigo modelos mínimos para dois tipos de isolantes de Mott do tipo 4/5d1: os que se apresentam na estrutura perovskita dupla ordenada (ODP) e os isostruturais aos materiais do tipo Kitaev. Seus modelos efetivos genericamente apresentam interações multipolares anisotrópicas e direcionalmente dependentes de um momento angular efetivo j = 3/2. Estes graus de liberdade são convenientemente escritos em termos de operadores de pseudospin s e pseudo-orbital τ semelhantes a operadores de spin e orbital de modelos do tipo Kugel-Khomskii com orbitais duplamente degenerados. A despeito da anisotropia, esses dois modelos realísticos apresentam simetrias globais contínuas no limite de acoplamento de Hund nulo que incrementam flutuações quânticas e possivelmente estabilizam uma fase do tipo QSL. A teoria de campo médio com partons foi usada para propor QSLs fermiônicos que serão chamados de líquidos spin-orbitais quânticos (QSOLs) devido à dependência deles com s e τ. Em ODPs, eu estudei um líquido de spin quiral com excitações do tipo férmion de Majorana e um espectro sem gap caracterizado por linhas nodais ao longo das arestas da zona de Brillouin. Essas linhas nodais são defeitos topológicos de uma conexão de Berry não-abeliana e o sistema apresenta estados de superfície dispersivos. Várias respostas experimentais foram calculadas para o QSOL quiral dentro da aproximação de campo médio e comparadas com os dados experimentais disponíveis para o candidato a líquido de spin Ba2YMoO6. Além disso, baseado em uma análise de simetria, discuto os operadores envolvidos nas amplitudes de espalhamento de raios-x ressonante para isolantes de Mott na configuração 4/5d1 e mostro que seções de choque de RIXS permitem estudar seletivamente os graus de liberdade de pseudospins e pseudo-orbitais. Para o caso particular do líquido spin-orbital quiral, essas seções de choque nos fornecem informações sobre o espectro de diferentes sabores de férmions de Majorana. Esse modelo possui uma simetria SU(4) emergente que é tornada explícita através de uma transformações de Klein nos graus de liberdade de pseudospin. Sabe-se que este modelo estabiliza um QSOL na rede colmeia, o que instigou uma investigação de QSOLs na generalização desta rede em três dimensões. A teoria de campo médio com partons foi usada novamente para propor estes líquidos quânticos, e o método de Monte Carlo Variacional (VMC) foi usado para calcular as energias das funções de onda projetadas. Os resultados numéricos mostraram que o QSOL de menor energia corresponde a um estado de fluxo-zero com superfície de Fermi envolvendo partons fermiônicos de quatro cores. Cálculos adicionais com VMC também demonstraram que este estado é estável à formação de ordem de plaquetas (tetramerização). A energia deste QSOL é altamente competitiva mesmo quando perturbações induzidas pelo acoplamento de Hund são incluídas, o que é mostrado através da comparação com estados ordenados simples. Extensões e perspectivas para trabalhos futuros são discutidas no final desta tese.

Indiana University-Purdue University Indianapolis (IUPUI) / The collapse of communism and the fall of the Soviet Union offered an unprecedented opportunity for the international community to support transitions to democracy in a region that had long known only totalitarian rule. Among the key players engaged in supporting efforts were U.S. grantmaking institutions, including both non-state and quasi-state aid providers. This thesis explores the motivations and evolving strategies of three different types of grantmaking institutions in a single country, Russia, with a particular focus on democracy aid provision from 1988-2002. The three types of grantmaking organizations examined through case studies include: the Ford Foundation, a private foundation with a history of international grantmaking spanning several decades; the Charles Stewart Mott Foundation, a private foundation known primarily for its domestic focus with a much shorter history of international grantmaking; and, finally, the National Endowment for Democracy, a U.S. government-created and heavily taxpayer-funded organization established as a private nonprofit organization to make grants specifically for democracy promotion. Motivating factors for initiating or expanding grantmaking in Russia in the late 1980s included a previous history of grantmaking in the region, a previously established institutional commitment to democracy promotion, international peace and security concerns, and interest from a top institutional leader. Over the course of the fourteen year period studied, five grantmaking features are identified as influencing the development of grantmaking strategies: professional grantmaking staff; organizational habit; global political, social, and economic environments; market and other funding source influences; and physical presence. Though subject to constraints, the non-state and quasi-state grantmaking institutions included in this study were able to avoid weaknesses identified with private philanthropy in other research and demonstrated a willingness to experiment and take risks, an ability to operate at the non-governmental level, and a commitment to long-term grantmaking, informed by expertise.

Les couches organiques greffées de façon covalente sur le silicium apparaissent comme des systèmes prometteurs tant sur le plan fondamental qu'en raison des nombreuses applications envisageables : couches minces diélectriques, capteurs chimiques ou biochimiques. Ce travail de thèse est consacré à l'étude de ces systèmes par diverses techniques. La stabilité chimique et électrique de l'interface au cours du temps et au sein d'un électrolyte de pH variable sont décrites. La morphologie de la surface est contrôlée par microscopie AFM. La nature chimique du système est déterminée par spectroscopie infrarouge en mode ATR et par spectroscopie de photoélectrons X. La qualité électrique de l'interface est étudiée par des mesures de photoluminescence, photopotentiel et Mott-Schottky. L'influence de la préparation sur les diverses caractéristiques du système est examinée. L'effet de charges adsorbées en surface a également été exploré par une titration quantitative de l'ionisation de groupements carboxyles greffés en surface. Enfin, une méthode originale de fonctionnalisation de couches alkyles greffées de compacité maximum par traitement dans un plasma doux oxydant est présentée. Le suivi du système, in situ par spectroscopie IR et ex situ par XPS, ainsi que la connaissance de la nature du plasma d'oxygène ont permis de mettre en évidence une destruction de la couche aux plus fortes puissances et une intégrité de celle-ci aux plus faibles puissances : un mécanisme de fonctionnalisation des chaînes dans ce régime est proposé.

This thesis explores prevailing and changing attitudes among Protestant Christians as manifested in the World Missionary Conference of 1910, held in Edinburgh, Scotland. It compares the conference to missionary literature to demonstrate how well it fit the context of the missionary endeavor during the Edwardian era. It examines the issues of race and empire in the thinking of conference participants. It pays particular attention to the position of West Africa and West Africans in conference deliberations. It suggests that the conference, which took place soon after the scramble for empire and just before World War I and the subsequent upsurge of nationalism and anti-colonialism, offers a valuable historical perspective on the uneven nature of globalizing Christianity.