The minority stress theory proposes that higher rates of mental illness among individuals who identify as lesbian, gay, or bisexual result from various factors that one may experience as a function of their minority status (Meyer, 1995, 2003). Such factors include internalized homophobia, concealment of one’s sexual identity, and the experiences of discrimination and rejection, whether real or perceived. This study investigated the relationship between minority stress and working memory. Based on the well documented research finding of the higher prevalence of mental illness among individuals who identify as lesbian, gay, or bisexual, relative to their heterosexual counterparts (S. D. Cochran, Sullivan, & Mays, 2003; Hatzenbuehler, 2009; Mays & Cochran, 2001), it was hypothesized that higher levels of minority stress would predict higher levels of psychological distress. In addition, models of chronic stress have predicted that individuals who are under constant stress conditions are more likely to have working memory deficits (Egeland et al., 2005; Schmader & Johns, 2003). Thus, it was hypothesized that the relationship between minority stress and working memory would be mediated by psychological distress. Identity valence is the evaluation of one’s identity and could be either positive or negative (Ashmore, Deaux, & McLaughlin-Volpe, 2004; Meyer, 2003). It was hypothesized that identity valence would further mediate the relationship between minority stress and working memory. Participants included 309 adults who identify as lesbian, gay, or bisexual (LGB), recruited via community-based and snowball sampling techniques (Meyer & Colten, 1999; Meyer & Wilson, 2009). Structural equation modeling (SEM) was utilized to examine direct and indirect effects of the relationship between minority stress and working memory. Results indicated that higher levels of working memory predict higher levels of psychological distress. Further, the relationship between minority stress and working memory was mediated through psychological distress and rumination. Finally, identity valence did not have the protective factor that was hypothesized and demonstrated in previous literature (Kertzner, Meyer, Frost, & Stirratt, 2009; Meyer, 2003). Rather, higher levels of identity valence predicted higher levels of psychological distress. Implications, strengths, limitations, and directions for future research are discussed. / School Psychology

Thesis. 1978. M.S.--Massachusetts Institute of Technology. Dept. of Earth and Planetary Science. / Microfiche copy available in Archives and Science. / Bibliography: leaves 80-84. / M.S.

Following the 2004 U.S. presidential election, articles from the Associated Press and major news organizations came to very different conclusions regarding the impact of young voters on the election outcome. While some media outlets framed the youth turnout as a success, others framed it as a failure. This experimental study (N=237) utilized a pre-test/post-test design to build upon research on framing theory and political information efficacy theory. Articles about youth voter turnout in the 2004 election served as the stimuli to test the effects of news frame valence and frame substance on college student respondents' levels of trust, cynicism, and political information efficacy. Results indicated that while valence and level of substance of a news article may affect political attitudes, changes between experimental groups were not significant. Cynicism was negatively correlated with political information efficacy and trust. Attitudinal measures accounted for a significant amount of variance in respondents' interest in the 2006 campaign as well as perceived importance of both political engagement and youth voter turnout in past and future campaigns. / Master of Arts

Titre de l'écran-titre (visionné le 16 janvier 2024) / L'insomnie est un trouble répandu dans la population ayant une influence négative sur la qualité de vie. Les rêves des personnes en souffrant possèdent une valence émotionnelle plus négative que ceux des bons dormeurs et cet aspect peut influencer le stress diurne. Toutefois, la valence émotionnelle des rêves est rarement ciblée par les méthodes de traitement actuelles. Puisque le rêve lucide peut permettre d'influencer le contenu des rêves et leur valence émotionnelle, et que cette compétence s'acquiert, il s'agit d'une piste de traitement méritant d'être explorée. Le premier objectif était de vérifier l'effet de la Technique d'Induction de Lucidité (TIL) sur la lucidité et la valence émotionnelle dans les rêves, le stress diurne, ainsi que sur la qualité du sommeil, grâce à un protocole à cas unique avec niveaux de base multiples. Neuf participants ont complété des questionnaires quotidiennement pendant quatre à huit semaines. Des améliorations entre le pré-traitement et le post-traitement sont notées chez la plupart des participants quant à l'efficacité du sommeil et le temps d'éveil après endormissement. Des effets positifs moins importants sont également observés quant à la lucidité, au stress diurne et à la valence émotionnelle positive et négative. Le second objectif était de vérifier l'évolution dans le temps de la qualité du sommeil, de la sévérité des symptômes d'insomnie, de la lucidité, et de l'humeur diurne suivant la TIL, à l'aide d'analyses de variance (ANOVAs) à mesure répétée. Les résultats montrent des améliorations significatives persistantes quant à la qualité du sommeil et la sévérité des symptômes de l'insomnie. Dans l'ensemble, les résultats montrent la pertinence de s'intéresser à l'induction de lucidité dans le traitement de l'insomnie.

A large amount of information concerning interatomic distances in the solid state is available, but little has been done in recent times to comprehensively filter, summarize and analyze this information. Here, I examine the distribution of bond lengths for 135 ions bonded to oxygen, using 180,331 bond lengths extracted from 9367 refined crystal structures collected from the Inorganic Crystal Structure Database (ICSD). The data are used to evaluate the parameterization of the bond-length—bond-valence relation of the bond-valence model. Published bond-valence parameters for 135 cations bonded to oxygen, and the various methods used in their derivation, are evaluated. New equations to model the relation are tested and the common form of the equation is found to be satisfactory. A new method (the Generalized Reduced Gradient Method, GRG method) is used to derive new bond-valence parameters for 135 cations bonded to oxygen, leading to significant improvements in fit for many of the ions. The improved parameterization is used to gain crystal-chemical insight into the milarite structure. A literature review of 350+ published compositions is done to review the end-members of the milarite group and to identify compositions that should have been described as distinct minerals species. The a priori bond-valences are calculated for minerals of this structure, and are used to examine the controls of bond topology on site occupancy, notably by localizing the major source of strain of the structure (the B site). Examination of the compositions of all known milarite-group minerals shows that compositions with a fully occupied B site are less common than those with a vacant B site, in accord with the idea that the B site is a local region of high strain in the structure. The bond-length distributions for the ions of the alkali and alkaline-earth metal families are examined. Variations in mean bond-lengths are only partly explained by the distortion theorem of the bond-valence model. I have found that bond length also correlates with the amount of vibrational displacement of the constituent ions. The validity of some uncommon coordination numbers, e.g., [3]-coordinated Li+, [3]-coordinated Be2+, is confirmed. / October 2016

Le bénéfice de l’implant cochléaire pour la compréhension de la parole en milieu calme, et même dans certains cas pour des situations auditives complexes telles que les environnements bruyants ou l’écoute de la musique est aujourd’hui connu. Si la compréhension de la parole est nécessaire à la communication, la perception des informations non verbales transmises par la voix de même que des expressions faciales est fondamentale pour interpréter le message d’un interlocuteur. Les capacités de perception des émotions non verbales en cas de surdité neurosensorielle évolutive ont été très peu explorées. Les travaux menés dans cette thèse ont pour objectifs d’évaluer la reconnaissance des émotions non verbales dans les modalités auditive et visuelle afin de mettre en évidence d’éventuelles spécificités chez les adultes présentant une surdité évolutive. Pour cela, nous avons réalisé quatre études comportementales dans lesquelles nous avons comparé leurs performances à celles de sujets contrôles normo-entendants. Nous avons évalué le jugement des émotions portées par la musique, la voix et les visages à partir d’un paradigme expérimental impliquant la reconnaissance de catégories émotionnelles (i.e. joie, peur, tristesse...) et la perception des dimensions de valence et d’éveil de l’émotion exprimée. Les études 1 et 2 ont porté sur la reconnaissance des émotions auditives après implantation cochléaire en examinant tour à tour la reconnaissance des émotions portées par la musique et la reconnaissance de celles portées par la voix. Les études 3 et 4 ont porté sur la reconnaissance des émotions visuelles et, en particulier, des expressions faciales avant et après implantation cochléaire. Les résultats de ces études révèlent l’existence d’un déficit de reconnaissance des émotions plus marqué dans le domaine musical et vocal que facial. Il apparaît aussi une perturbation des jugements d'éveil, les stimuli étant perçus moins excitants par les patients que par les normo-entendants. Toutefois, la reconnaissance des voix et des musiques, bien que limitée, était supérieure au niveau du hasard démontrant les bénéfices de l'implant cochléaire pour le traitement des émotions auditives. En revanche, quelle que soit la modalité étudiée, les jugements de valence n'étaient pas altérés. De manière surprenante, les données de ces recherches suggèrent de plus que, chez une partie des patients testés, la reconnaissance des émotions faciales peut être affectée par la survenue d'une surdité évolutive suggérant les conséquences de la perte auditive sur le traitement des émotions présentées dans une autre modalité. En conclusion, il semblerait que la surdité, de même que l'insuffisance d’informations spectrales transmises par l’implant cochléaire, favorisent l'utilisation de la communication verbale au détriment de la communication non verbale. / While cochlear implantation is quite successful in restoring speech comprehension in quiet environments other auditory tasks, such as communication in noisy environments or music perception remain very challenging for cochlear implant (CI) users. Communication involves multimodal perception since information is transmitted by vocal and facial expressions which are crucial to interpret speaker’s emotional state. Indeed, very few studies have examined perception of non verbal emotions in case of progressive neurosensorial hearing loss in adults. The aim of this thesis was to test the influence of rehabilitation by CI after acquired deafness on emotional judgment of musical excerpts and in non verbal voices. We also examined the influence of acquired post-lingual progressive deafness on emotional judgment of faces. For this purpose, we conducted four experimental studies in which performances of deaf and cochlear implanted subjects were compared to those of normal hearing controls. To assess emotional judgment in music, voices and faces, we used a task that consisted of emotional categories identification (happiness, fear, anger or peacefulness for music and neutral) and dimensional judgment of valence and arousal. The first two studies evaluated emotional perception in auditory modality by successively examining recognition of emotions in music and voices. The two following studies focused on emotion recognition in visual modality, particularly on emotional facial expressions before and after cochlear implantation. Results of these studies revealed greater deficits in emotion recognition in the musical and vocal than visual domains as well as a disturbance of arousal judgments, stimuli being perceived less exciting by CI patients as compared to NH subjects. Yet, recognition of emotions in music and voices, although limited, was performed above chance level demonstrating CI benefits for auditory emotions processing. Conversely, valence judgments were not impaired in music, vocal and facial emotional tests. Surprisingly, results of these studies suggest that, at least for a sub-group of patients, recognition of facial emotions is affected by acquired deafness indicating the consequences of progressive hearing loss in processing emotion presented in another modality. Thus, it seems that progressive deafness as well as the lack of spectral cues transmitted by the cochlear implant might foster verbal communication to the detriment of the non verbal emotional communication.

Cette thèse porte sur la compréhension et le développement de matériaux innovants en tant que composant actif pour les mémoires résistives à changement de valence (VCM), qui constitue une sous-catégorie des mémoires résistives où des réactions d’oxydoréduction sont à l’origine du mécanisme de commutation résistive. Leur incorporation dans les circuits intégrés nécessite une tension (ou un courant) électrique pour lire et programmer la mémoire, cependant leurs fonctionnalités dépend essentiellement des propriétés chimiques des matériaux constituant la mémoire. Dans ce manuscrit nous étudions les propriétés du composé La2NiO4+δ, un conducteur mixte d’ions et d’électrons qui de par sa conduction d’ions oxydes dans le volume du matériau offre un terrain de jeu prometteur pour les VCMs. Nous avons pu obtenir des films minces de La2NiO4+δ fortement texturés sur des substrats monocristallins de SrTiO3 par dépôt chimique en phase vapeur à partir de l’injection pulsée de précurseurs métalorganiques (PiMOCVD). Des recuits sous atmosphère contrôlée ont permis de faire varier le contenu en oxygène et d’ajuster les propriétés semiconductrices-type p de La2NiO4+δ par un mécanisme d’auto-dopage. Une sur-stœchiométrie en oxygène dans la plage 0 ≤ δ ≤ 0.08 induit une variation de résistivité de 5.7 Ω.cm à 5.3x10-3 Ω.cm pour un recuit sous hydrogène ou sous oxygène, respectivement. Les films minces de La2NiO4+δ ont ensuite été utilisés comme base dans la conception d’hétérostructures métal/La2NiO4+δ/métal. Le rôle important de la jonction métal/oxyde sur les propriétés des VCMs de type interfaciales est discuté en détails. En particulier, un contact ohmique avec La2NiO4+δ est obtenu en utilisant un matériau d’électrode tel que le Pt ayant un travail de sortie élevé, alors qu’un contact rectifiant est obtenu avec Ti résultant de la présence d’une fine couche (~8 nm) de TiOx formée de manière spontanée à l’interface Ti/La2NiO4+δ. Une hétérojunction asymétrique Pt/La2NiO4+δ/Ti a été sélectionnée comme prototype afin d’évaluer les propriétés memristives de composants basés sur La2NiO4+δ. Un changement de résistance bipolaire a été mesuré ainsi qu’une possibilité de programmation largement multi-niveaux lorsque la mémoire est stimulée de manière pulsée. Les résultats prometteurs obtenus par ce premier prototype sont ensuite étendus pour la première fois à un système plus complexe de bicouches La2NiO4+δ/LaNiO3. Des propriétés de relaxation ont été mesurées, rendant ces mémoires intéressantes pour leur utilisation en tant que mémoire volatile pour un filtrage dynamique dans des applications neuromorphiques. / This thesis is focused on the understanding and development of novel materials for valence-change memories (VCMs), a type of resistive switching memories in which the memory storage mechanism is based on internal redox reactions. VCMs are in essence electrochemical systems. Their implementation in integrated electronic circuits relies on a voltage (or current) to measure and operate the memory, but their functionality is highly dependent on the chemical properties of the materials constituting the memory. In this work we present how the mixed ionic-electronic conducting La2NiO4+δ compound offers an interesting playground for VCM applications due to its intrinsic bulk oxygen-ion conducting properties. We have successfully prepared La2NiO4+δ in the form of highly oriented thin films on SrTiO3 single crystal substrates using pulsed-injection chemical vapour deposition (PiMOCVD). Post-annealing treatments in oxidizing/reducing atmospheres allow tuning the oxygen content and the p-type semiconducting properties of La2NiO4+δ due to a self-doping mechanism. The obtained oxygen over-stoichiometry in the 0 ≤ δ ≤ 0.08 range induced a variation of the film resistivity between 5.7 Ω.cm and 5.3x10-3 Ω.cm for hydrogen or oxygen-annealed samples, respectively. The optimized La2NiO4+δ thin films have been used as a base for the microfabrication of metal/La2NiO4+δ/metal heterostructures. The important role of the metal/oxide junction in interface-type VCMs is discussed in detail. In particular, an ohmic contact is obtained with La2NiO4+δ when using a high work function metal such as Pt, while rectifying contact properties are obtained when using Ti due to the presence of a spontaneously-formed TiOx interlayer (~8 nm) at the Ti/L2NO4 interface. An asymmetric Pt/La2NiO4+δ/Ti heterojunction has been selected as a first prototype to assess the memory capabilities of a La2NiO4+δ-based memristive device. A continuous bipolar analogue-type memory behaviour has been measured, together with strong multilevel programing capabilities when operated in pulsed mode. In addition, the promising results offered by this prototypical device have been extended for the first time to La2NiO4+δ/LaNiO3 bilayers, showing memory relaxation properties, which are potentially interesting for short-term memory and filtering applications in neuromorphic-based computational hardware.

Os nitretos do grupo III (BN, AIN,Gan e InN) e suas ligas ternárias Al-GaN e InGaN proporcionam, recentemente, um extraordinário avanço na fabricação de dispositivos opto-eletrônicos operando na região do espectro correspondente ao verde-azul-UV e na produção de dispositivos eletrônicos de alta frequência, alta temperatura e alta potência. Estes materiais semicondutores de gap largo atraíram enorme atenção dos pesquisadores nos últimos anos. O objetivo desta tese é o estudo das propriedades vibracionais dos nitretos do grupo III referente tanto ao cristal perfeito, quanto ao cristal com defeito. Utilizamos como base a Teoria Clássica do Crital Harmônico e o Método das Funções de Green. Com a Teoria Clássica do Cristal Harmônico, juntamente com o Método do Valence Force Filed e o Método da Soma de Ewald, que permitem gerar a matriz dinâmica do sistema, determinamos o comportamento vibracional dos nitretos binários e das ligas ternárias. A utilização destes métodos permitiu a obtenção do espectro de fônons dos nitretos binários, e o estudo do comportamento dos modos ópticos em para as ligas ternárias. A partir da Função de Green do cristal perfeito e da Função de Green do cristal com defeito, obtivemos as frequências e os modos vibracionais localizados e ressonantes introduzidos pela impureza de C e As em GaN. A partir das densidades de estados do cristal perfeito e do cristal com defeito, calculamos a entropia de formação da vacância de N em GaN. Os resultados obtidos foram usados na interpretação de dados experimentais disponíveis na literatura, relativos às propriedades vibracionais dos nitretos na estrutura wurtzita, e na predição e análise de dados experimentais obtidos pelo grupo do Laboratório de Novos Materiais Semicondutores do Instituto de Física da USP para os nitretos zincblende. / The group-III nitrides (BN, AIN, GaN and InN) and their ternary alloys AlGaN and InGaN generated recently an extraordirlary progress in the production of optoelectronic devices operating in the green-blue-UV region of the spectrum, and in the production of electronic devices of high frequency, high temperature and high power. These wide gap semiconductor materials attracted enormous attention in the last years. The objective of this Thesis was to study the vibrational properties of the bulk III nitrides, without and with defects. To accomplish this study we used the Classic Theory of the Harmonic Crystal and the Method of the Green\'s Functions. With the Classic Theory of the Harmonic Crystal, together with the Valence Force Field Method and the Method of the Ewald\'s Sum, that allow to generate the dynamic matrix of the system, we determined the vibrational behavior of the binary nitrides and of the ternary alloys. The use of these methods allowed us to obtain the phonon spectra of the binary nitrides and to study the behavior of the optical modes at of the ternary alloys. Starting from the Green\'s Function of the perfect crystal and the Green\'s Function of the crystal with defect, we obtained the frequencies and the localized and resonant vibrational modes introduced by the C and As impurities in GaN. Starting from the densities of states of the perfect crystal and of the crystal with defect, we calculated the formation entropy of the N vacancy in GaN. The obtained results were used in the interpretation of experimental data related to the vibrational properties of the wurtzite nitrides available in the literature, and in the prediction and analysis of experimental results obtained for zincblende nitrides by the group of the New Semiconductors Materials Laboratory of t11c Physics Institute at USP.

La notion de valence est très répandue à l’échelle de l’atome et est à l’origine de la diversité et des propriétés des composés covalents (molécules, macromolécules, cristaux). L’un des grands challenges à l’heure actuelle est de décliner cette notion de valence à l’échelle des particules, qui pourraient devenir des briques élémentaires programmées, c’est-à-dire la matière première de nouveaux matériaux qui seraient obtenus par assemblage spontané. Dans ce contexte, nous avons développé des particules à patchs possédant à leur surface des discontinuités chimiques et topologiques permettant de limiter le nombre de particules voisines et d’engendrer des interactions directionnelles avec ces dernières. L’objectif de nos travaux consiste dans un premier temps à imiter les hybridations simples de l’atome de carbone divalent (sp), trivalent (sp2) et tétravalent (sp3). Des particules de silice contenant un nombre spécifique de cavités dans lesquelles se trouvent des chaines de polystyrène ont été synthétisées et fonctionnalisées sélectivement. Des molécules colloïdales constituées d’une particule à patchs, au centre, entourée de nanoparticules satellites en nombre contrôlé ont été obtenues par assemblages covalents ou supramoléculaires. Ces premiers clusters miment la géométrie de molécules simples telles que CF4, BF3, CO2 ou H2O. En différenciant des lots de satellites soit par leur taille, soit par leur composition chimique, nous avons montré qu’il est possible d’étendre la formation de molécules colloïdales vers de structures plus complexes du type AXnYm (n+m = 4) ou encore des molécules colloïdales chirales. Enfin, nous avons développé une autre voie permettant d’obtenir de nouveaux atomes colloïdaux contenant un nombre défini de patchs surfaciques de taille contrôlée. / The concept of valence is well-known at the atomic level and is at the origin of the diversity and properties of covalent compounds (molecules, macromolecules, crystals). Nowadays, one of the major challenges is to decline this notion of valence at the scale of colloidal particles, which could become programmed elementary bricks, that is to say the raw material of new materials that would be obtained by spontaneous assembly. In this context, we have developed patchy particles with chemical and topological discontinuities at their surface that limit the number of neighboring particles and induce directional interactions with them. The objective of our work consists first in imitating simple hybridizations of the divalent (sp), trivalent (sp2) and tetravalent (sp3) carbon atoms. The silica particles containing a specific number of cavities in which residues of polystyrene chains are chemically and selectively functionalized. Colloidal molecules consisting of a patchy particle, in the center, surrounded by satellite nanoparticles in controlled number were obtained by covalent or supramolecular routes. These first clusters mimic the geometry of simple molecules such as CF4, BF3, CO2 or H2O. By differentiating batches of satellites either by their size or by their chemical composition, we have shown that it is possible to extend the formation of colloidal molecules to more complex AXnYm (n + m = 4) structures or chiral colloidal molecules. Finally, we have developed another way to obtain new colloidal atoms containing a precise number of surface patches with a controlled area.

Os nitretos do grupo III (BN, AIN,Gan e InN) e suas ligas ternárias Al-GaN e InGaN proporcionam, recentemente, um extraordinário avanço na fabricação de dispositivos opto-eletrônicos operando na região do espectro correspondente ao verde-azul-UV e na produção de dispositivos eletrônicos de alta frequência, alta temperatura e alta potência. Estes materiais semicondutores de gap largo atraíram enorme atenção dos pesquisadores nos últimos anos. O objetivo desta tese é o estudo das propriedades vibracionais dos nitretos do grupo III referente tanto ao cristal perfeito, quanto ao cristal com defeito. Utilizamos como base a Teoria Clássica do Crital Harmônico e o Método das Funções de Green. Com a Teoria Clássica do Cristal Harmônico, juntamente com o Método do Valence Force Filed e o Método da Soma de Ewald, que permitem gerar a matriz dinâmica do sistema, determinamos o comportamento vibracional dos nitretos binários e das ligas ternárias. A utilização destes métodos permitiu a obtenção do espectro de fônons dos nitretos binários, e o estudo do comportamento dos modos ópticos em para as ligas ternárias. A partir da Função de Green do cristal perfeito e da Função de Green do cristal com defeito, obtivemos as frequências e os modos vibracionais localizados e ressonantes introduzidos pela impureza de C e As em GaN. A partir das densidades de estados do cristal perfeito e do cristal com defeito, calculamos a entropia de formação da vacância de N em GaN. Os resultados obtidos foram usados na interpretação de dados experimentais disponíveis na literatura, relativos às propriedades vibracionais dos nitretos na estrutura wurtzita, e na predição e análise de dados experimentais obtidos pelo grupo do Laboratório de Novos Materiais Semicondutores do Instituto de Física da USP para os nitretos zincblende. / The group-III nitrides (BN, AIN, GaN and InN) and their ternary alloys AlGaN and InGaN generated recently an extraordirlary progress in the production of optoelectronic devices operating in the green-blue-UV region of the spectrum, and in the production of electronic devices of high frequency, high temperature and high power. These wide gap semiconductor materials attracted enormous attention in the last years. The objective of this Thesis was to study the vibrational properties of the bulk III nitrides, without and with defects. To accomplish this study we used the Classic Theory of the Harmonic Crystal and the Method of the Green\'s Functions. With the Classic Theory of the Harmonic Crystal, together with the Valence Force Field Method and the Method of the Ewald\'s Sum, that allow to generate the dynamic matrix of the system, we determined the vibrational behavior of the binary nitrides and of the ternary alloys. The use of these methods allowed us to obtain the phonon spectra of the binary nitrides and to study the behavior of the optical modes at of the ternary alloys. Starting from the Green\'s Function of the perfect crystal and the Green\'s Function of the crystal with defect, we obtained the frequencies and the localized and resonant vibrational modes introduced by the C and As impurities in GaN. Starting from the densities of states of the perfect crystal and of the crystal with defect, we calculated the formation entropy of the N vacancy in GaN. The obtained results were used in the interpretation of experimental data related to the vibrational properties of the wurtzite nitrides available in the literature, and in the prediction and analysis of experimental results obtained for zincblende nitrides by the group of the New Semiconductors Materials Laboratory of t11c Physics Institute at USP.