Abstract In this thesis, the theory of static magnetic resonance spectral parameters of nuclear magnetic resonance (NMR) and electron spin resonance (ESR) spectroscopy is investigated in terms of the molecular Breit-Pauli Hamiltonian, which is obtained from the relativistic Dirac equation via the Foldy-Wouthuysen transformation. A leading-order perturbational relativistic theory of NMR nuclear shielding and spin-spin coupling tensors, and ESR electronic g-tensor, is presented. In addition, the possibility of external magnetic-field dependency of NMR parameters is discussed. Various first-principles methods of electronic structure theory and the role of one-electron basis sets and their performance in magnetic resonance properties in terms of their completeness profiles are discussed. The presented leading-order perturbational relativistic theories of NMR nuclear shielding tensors and ESR electronic g-tensors, as well as the theory of the magnetic-field dependent NMR shielding and quadrupole coupling are evaluated using first-principles wave function and density-functional theories.

The purposes of this study were (1) to determine the difference between the cognitive style of low and high achieving students in an algebra course in a traditional high school and the cognitive style of low and high achieving students in an algebra course in a high school for dropouts, and (2) to determine the difference between the cognitive styles of low and high achieving males and females in an algebra class in a traditional high school and in a high school for dropouts. It was hypothesized that (1) low achieving mathematics students are more field-dependent than high achieving mathematics students in both the traditional high school and in the high school for dropouts, (2) female students are more field-dependent than male students in the mathematics classes of both schools, and (3) there will be a significant interaction on the achievement variable and the sex variable with respect to field-dependence in both schools.

Le vieillissement entraîne une dégradation des mécanismes sensoriels d’intégration pouvant se manifester dans les tâches de la vie quotidienne des seniors par une perte d'autonomie et des risques de chute. Parmi les facteurs contribuant à l’augmentation de ces risques, certains pourraient relever d’une dégradation de la (re)pondération des signaux sensoriels se traduisant par une augmentation de la dépendance aux informations visuelles et aux références spatiales associées.Examiner la dépendance au référentiel visuel (DRV) dans le contexte du vieillissement permet ainsi de mieux comprendre:• si des effets d’âge sur la cognition et/ou la sensorimotricité sont liés à l’augmentation de la DRV;• si la DRV majorée des seniors indique un mode préféré de référentiation spatiale ou une conséquence des déficits liés à l'âge;• l’évolution de ces associations et ces mécanismes en étudiant des jeunes adultes, des adultes d'âge intermédiaire et des seniors.Dans le Chapitre 2, nous avons examiné les facteurs associés à une plus grande DRV avec l'âge. Nous avons confirmé les résultats classiques de la littérature en montrant une augmentation de la DRV avec l’âge, de plus celle-ci était associée avec une réduction de i) l’effet Aubert, indiquant une réduction de la dépendance au référentiel égocentré (DRE), ii) la capacité de traitement d'attention visuelle parallèle, et iii) la stabilité de fixation visuelle.Nous avons étudié ensuite les comportements d’orientation et de stabilisation de nos participants pendant des tâches posturales, et de marche face à des flux optiques linéaires projetés au sol. Dans le Chapitre 3, nos participants se tenaient 1) en posture érigée pieds serrés ou 2) marchaient sur place (MSP - contacts podaux intermittents) face à 1- une stimulation visuelle statique, 2- un flux optique naturel (aucune stimulation), 3- en approche ou 4- en recul. Les flux optiques ont surtout influencé la MSP induisant des dérives antéroposterieures de la tête, du tronc et du centre de pression (CdP). Les dérives étaient plus marquées chez les seniors par rapport aux autres groupes. Ces participants ont aussi montré des dérives naturelles en condition de MSP, i.e. sans stimulation visuelle projetée. La direction du flux optique a provoqué les effets les plus importants sur la dérive du CdP en association avec i) une DRV supérieure, ii) une DRE réduite et iii) une plus grande dérive naturelle,Dans le chapitre 4, nous avons étudié l'influence de ces mêmes flux sur le contrôle des paramètres de la marche et sur la stabilisation de la tête au cours de la marche. La dépendance au cadre de référence visuel s’est manifestée chez les seniors dans les conditions de i) flux naturel par une stratégie d’abaissement de la tête et une capacité réduite de stabilisation de la tête sur l’espace dont on peut penser que ces comportements visaient à maximiser l’utilisation des indices visuels disponibles, et ii) flux visuels imposés, par une réorientation du tronc et une augmentation de la fréquence du pas. Les résultats montrent aussi une adoption plus fréquente de la stratégie de stabilisation de la tête sur l’espace en conditions imposées de stimulation visuelle. Ce résultat suggère qu’un renforcement artificiel du flux optique mène à une adaptation posturale permettant une meilleure intégration des informations sensorielles pendant la marche.Nos résultats complètent les connaissances actuelles sur les relations entre la DRV et le contrôle sensorimoteur en fonction de la tâche perceptivo- motrice avec l’âge. Cette dépendance semble être associée à une réduction de l'exploitation du cadre de référence égocentrée en termes de perception de l’orientation du corps/verticale et de mouvement- propre, et se manifeste différemment selon la tâche. Enfin, notre travail ouvre des pistes de réflexion pour tenir compte de la DRV exacerbée dans la conception de protocoles d’entraînement pour des seniors plus dépendants. / Aging entails deficits in the mechanisms of sensory integration which may affect daily living tasks in old adults, ultimately leading to loss of autonomy and health risks, notably falls. Among the factors contributing to these risks, some may be associated with a degradation in sensory (re)weighting, leading to a greater reliance on visual cues and the associated frames of reference (FoR) (visual field dependence).Our aim was to study how preferential modes of spatial referencing influence sensorimotor control. Examining visual field dependence in the context of aging thus allows to better understand:• if age-related cognition and/or sensorimotor deficits are associated with increased reliance on the visual FoR;• whether this reliance indicates a preferred mode of spatial referencing or a consequence of age-related deficits;• how the above associations and mechanisms evolve by studying young, middle-aged and old adults.We first examined possible factors associated with greater reliance on the visual FoR with age (Chapter 2). We confirmed classic literature reports of increased visual field dependence in old age, and uncovered an association between greater visual field dependence and reduced i) reliance on the egocentric FoR, ii) parallel attentional visual processing ability, and iii) visual fixation stability.We subsequently examined the orientation and stabilisation behaviour of our participants during postural tasks and while walking under different conditions of linear ground optic flow. In Chapter 3, participants stood quietly or stepped in place (SIP – intermittent podal contacts with the ground surface) while confronted with 1- natural optic flow (no stimulus), 2- a static visual stimulation, 3- approaching and 4- receding optic flow. The results showed that the optic flow stimuli influenced SIP primarily as evidenced by anteroposterior drifting of the head, trunk and centre of pressure (COP). Old adults had larger amplitudes of drift compared to the younger participants, and drifted even under natural flow (natural drift) during SIP, indicating reduced egocentric self-motion perception. The most important directional optic flow effects were on the COP and were associated with i) increased reliance on the visual FOR, ii) reduced reliance on the egocentric FoR, and iii) greater natural drift.In Chapter 4 we investigated the influence of ground optic flow on the control of walking and head stabilisation. Reliance on the visual FoR in old adults was manifested under conditions of i) natural flow by a reduced head pitch orientation and ability to stabilise their head in space, which may indicate a strategy to maximise the salience of available visual cues and ii) imposed optic flow, by a re-orientation of the trunk in pitch and increase in stepping frequency. Our results also revealed a general improvement of head stabilisation under conditions of imposed visual stimulation towards a more frequent adoption of the head stabilisation in space strategy. This suggests that the artificial enhancement of optic flow provokes a postural adaptation in order to optimise sensory information processing when walking.Our findings extend current knowledge on the association between reliance on the visual FoR and sensorimotor control across adulthood and depending on the perceptivo-motor task. It is evident that this reliance is linked to a reduction in the exploitation of the egocentric FoR in terms of body orientation and self-motion perception, and that its manifestation depends on the task. Finally, our work provides insights for the design of training protocols aimed at frailer olds taking into account exacerbated reliance on the visual FoR.

<p> The theoretical treatment of the induced torque problem is discussed, and equations describing the functional form of the torque amplitude are derived on the basis of a model calculation valid in the high field limit. This functional form is applied to a detailed interpretation of the open orbit structure in gallium, cadmium, zinc and copper. </p> <p> An investigation of the open orbit structure in gallium at l.4°K using this technique has yielded direct information on the connectivity of the sixth-band hole surface. This surface supports a k(c)-trajectory for all field directions in the ab plane, except within 0.1° of the a-axis. A k(a)-trajectory of lower conductivity is reported over a 10° range of field direction centred (32°±2°) from the b-axis in the be plane. These data, in addition to the highly anisotropic amplitude and field dependence of the k(c) -trajectory, require that this surface contact the Brillouin zone boundary at both the k(a) -and k(c) -faces. The present data are compared with available models of the sixth band hole surface, and are found to be in excellent agreement with the predictions of recent pseudopotential calculations . The possibility of magnetic breakdown in the k(c)-trajectory for B|| b-axis is discussed. Finally, a non-linear frequency dependence, and an anisotropic non-quadratic field dependence are understood to occur through the long mean free path and short skin depth parameters in gallium at l.4°K. </p> <p> In cadmium, the induced torque amplitude due to the [0001]-open trajectory tends to saturation at high field intensities for all observation directions. This effect is attributed to magnetic breakdown between the first-and secondhand hole surfaces through the spin·-orbit interaction energy 'gap near the H-symmetry point in the AHL plane. This magnetic breakdown effect is analyzed on the basis of a linear chain model and the theoretical curves of Falicov and Sievert. Detailed analysis indicates the possibility of two separate breakdown probabilities across the HL and HA gaps; for <1010> directions , breakdown fields of 10.8 k0e and (as low as) 0.72 k0e are indicated . A similar range of breakdown fields is indicated for all field directions in the (0001) plane. </p> <p> In zinc, the induced torque technique is used to investigate magnetic breakdown effects in the [0001]-trajectory for specific field directions in the basa l plane. These effects are attributed to the onset of partial breakdown between the monster and cap surfaces near the H-symrnetry points, for field intensities above 16 kOe. The linear chain model is shown to be an inappropriate description of breakdown effects in zinc. An onset field of 16 kOe for <1120> is determined; no breakdown is observed along <lOIO> below 20 kOe. In addition, magnetic breakdown effects occurring in the basal orbits of zinc were investigated. The general monotonic rise in torque amplitude with field intensities is fitted to the theoretical expressions of Falicov, Pippard, and Sievert. The giant quantum oscillations arising through coherence-effect modulation of the breakdown probability are shown consistent with earlier data. </p> <p> The technique is applied to a general survey of the various types of open orbits existing in copper, and the general applicability of the sample torque equations to both compensated and uncompensated metals is demonstrated. </p> / Thesis / Doctor of Philosophy (PhD)

本研究旨在討論台灣國中師生認知風格與學生英文學習表現的關係。此研究目的是要探討(1)不同認知風格的學生在英文學習表現上是否有顯著性的相關，(2)不同認知風格的老師在教學成效方面是否有顯著性的相關，(3)師生認知風格相符合的學生群和不相符合的學生群在英文學習表現方面是否有顯著性的相關。 研究樣本以新竹一所國中242位學生及4位老師為研究對象。藏圖測驗用來區分研究對象之認知風格是否為場地獨立型或場地依賴型之學習者。此242位學生皆參與全民英檢之聽、讀、寫測驗;此外，研究者亦對師生進行個別訪談以獲得更進一步的解釋。 本研究採描述統計及Pearson積差相關進行資料分析。研究結果顯示(1)場地獨立型學生在聽、讀、寫的學習表現上較場地依賴型學生佳，並有顯著性相關；(2)場地獨立型老師所教的學生在聽、讀、寫的學習表現上雖較場地依賴型老師所教的學生佳，卻無顯著性相關；然而當男女學生分開進行檢測時，場地獨立型老師所教的女學生在聽力的學習表現方面較場地依賴型老師所教的女學生佳，並有顯著性相關；(3)師生認知風格不相符合的學生群在聽、讀、寫的學習表現上雖較師生認知風格相符合的學生群佳，卻無顯著性相關；而當進行更進一步的數據檢測時，師生場地依賴型風格不相符合的學生群在聽力及寫作的學習表現方面較師生場地依賴型風格相符合的學生群佳，並有顯著性相關；此外，其老師為場地依賴型的場地獨立型學生在閱讀的學習表現上較師生場地依頼型風格相符合的學生群佳，並有顯著性相關。訪談的結果發現，師生場地獨立型風格相符合的學生群能受惠於教師的教學，而師生場地依賴型風格相符合的學生群能夠在與教師的人際互動中受益。 最後，研究者根據研究發現提出數點建議。首先，對於師生認知風格的確認在教學上有其必要性。其次，教師的教學應力求多樣化，並且對於不同認知風格的學生能施予不同的教學法。再者，師資培育者應提供相關的教學訓練，幫助英語教師在教學上能依據學生不同的認知風格予以不同的教法。最後，本研究建議未來能有更多的研究探討場地獨立型或場地依賴型的師生在英語教學或學習中所扮演的角色，並提供更多更有建設性的貢獻。 / The present study aimed to investigate the relationship between student-teacher field-independence-dependence cognitive styles and students’ English performance in a Taiwanese junior high school. The purpose of this study was to explore: (a) different language tasks achieved successfully by students with different cognitive styles, (b) the teaching effectiveness of teachers with different cognitive styles, and (c) language performance under matching cognitive styles between students and teachers. Two hundred forty-two student participants and four teacher participants from a junior high school in Hsin-chu city were chosen in this study. The Hidden Figures Test (HFT) was conducted to measure the participants’ cognitive styles to be field independence (FI) or field dependence (FD). These 242 students took the General English Proficiency Tests (GEPT) with regard to listening, reading and writing. Interview was also given to both the student and teacher participants. The collected data were analyzed by descriptive statistics and Pearson product-moment correlations. The results show: (a) FI students performed better than FD students in the listening, reading and writing test, and there was a significant correlation between FI students and students’ English performance in the listening, reading and writing test; (b) students with FI teachers outperformed students with FD teachers in the listening, reading and writing test, but there was no significant correlation between teachers’ cognitive styles and students’ performance in the listening, reading and writing test; but when the data were re-tested between female groups and male groups, female students with FI teachers were found to perform better than those with FD teachers in the listening test, and there was a significant correlation between female with FI teachers and students’ performance in the listening test; (c) student-teacher FI/FD mismatch groups performed better than student-teacher FI/FD match groups in the listening, reading and writing test, but there was no significant correlation between student-teacher FI/FD mismatch groups and students English performance in the listening, reading and writing test; however, the further examination indicated that FD mismatch groups performed better than FD match groups in the listening and writing test, and there was a significant correlation between FD mismatch groups and students’ performance in the listening and writing test; and the further examination also revealed that FI students with FD teachers outperformed FD students with FD teachers in the reading test, and there was a significant correlation between FI students with FD teachers and students’ English performance in the reading test. The result of the interview revealed that FI match groups benefited from the teacher instruction while FD match groups benefited from the interpersonal aspect of the teachers. Pedagogically, the findings of the study suggested the necessity of the awareness of students’ and teachers’ cognitive styles; in addition, teachers were suggested to be cognitive-flexible, and teacher education programs were also advised to offer related language training to assist teachers in achieving cognitive flexibility. Further research should be conducted to understand to what extent field independence/dependence plays a role in how students learn and how teachers teach, hence providing more constructive insights for English language education.

The problem of this study was to discover the relationship between field-independent and field-dependent cognitive styles and social behaviors during free-play of preschool children in a school setting. This study also compared the field-independent and field-dependent cognitive styles and social behaviors during free-play between age-groups and sex-groups. Thirty-six children from a university child development laboratory were subjects. They were selected from a 3-year-old classroom and a 4-year-old classroom. The research instrument, the Preschool Embedded Figures Test, was utilized to measure field-independent and field-dependent cognitive styles. The children's social behaviors were observed during free-play for four consecutive weeks. The nine categories of social behavior were solitary, parallel, and group play; .unoccupied, onlooker, transitional, and aggressive behaviors; and conversations with teachers and conversations with peers. Correlations between field-independent and field-dependent cognitive styles and social behaviors indicated that field-independence/field-dependence was related to social orientations in preschool children and also related to the choice of play activity. Field-dependent children tended to engage in conversations with teachers more often than field-independent children. Four-year-old children who were field-independent tended to spend more time in solitary play than 4-year-old children who were field-dependent. Four-year-old boys who were field-independent tended to play more often in the manipulative learning center than 4-year-old boys who were field-dependent. There were significant differences between age-groups but not significant differences between sex-groups in field-independence/field-dependence. Some social behaviors were significantly different between age-groups and sex-groups. Three-year-old children participated significantly more in physically aggressive behavior and less in conversations with peers than 4-year-old children. Boys engaged significantly more in aggressive behavior than girls.

The present diploma thesis focuses on the relation of the bilingualism and the cognitive style of field dependence/independence. Its first theoretical chapter deals with the issue of cognitive styles, in particular field dependence/independence, its history, possibilities of testing, namely the Embedded Figures Test and its group and online modifications. The second chapter of the theoretical part provides a characteristics and description of the phenomenon of bilingualism, its classification and a review of selected studies of bilingualism in relation to cognitive abilities and with the concept of field (in)dependence. During the former researches, higher tendency to the field-independence in youth non-adult bilinguals was proved. The purpose of the empirical part of this thesis aims to find, using the Online Group Embedded Figures Test, if the bilinguals still differ in this higher tendency from monolinguals in the adulthood. Based on the sample of 30 adult individual natural bilinguals, whose results in the Online GEFT test were compared to the results of 30 adult monolinguals in the same test, a statistically significant difference was not proved. From this result we can claim, that in adulthood, the difference of the field-independence between bilingual and monolingual population tends to...

La contribution relative des différentes entrées sensorielles dans le contrôle postural a souvent été étudiée dans le cadre de la posture érigée fondamentale. L’objectif de nos travaux a été de déterminer cette contribution dans deux postures relativement proches dans leur configuration : l’appui tendu renversé (ATR) et la verticale inversée (VI) en milieu aquatique. Si la vision est souvent considérée comme information principale dans le contrôle postural de la station érigée, la configuration structurelle (champ visuel restreint en ATR, immersion de l’œil en VI) de ces deux postures laisse imaginer un fonctionnement différent. La perturbation des différents capteurs sensoriels impliqués dans le contrôle postural a permis d’observer la réorganisation mise en place par le système nerveux central (SNC) pour y remédier. De plus la prise en compte d’un facteur perceptif comme la dépendance au champ visuel nous a paru être un élément pertinent pour tenter d’observer d’éventuelles différences interindividuelles dans les comportements des sujets. La perturbation du contrôle postural a été évaluée au travers d’une analyse cinématique et d’une analyse stabilométrique de l’ATR (analyse classique et non-linéaire). Les résultats de ces analyses laissent entrevoir des différences de stratégie entre les sujets dépendants et indépendants au champ visuel dans le contrôle de l’appui tendu renversé, ce qui ne semble pas être le cas en verticale inversée / The relative contribution of the different sensory inputs in erect postural control has often been studied. The aim of this work is to determine this contribution in two positions relatively close in their configuration: the handstand and the upside-down posture in water. If vision is often considered as the main information in postural control, the structural configuration (restricted visual field in handstand, eye’s immersion in upside-down posture) of these two postures lets imagine a different operation. Disruption of sensory receptors involved in postural control has allowed observing the reorganization implemented by the central nervous system (CNS). In addition, the visual field dependence appeared to be a relevant factor to observe interindividual behavioral differences. Disturbance of postural control was assessed through a kinematic analysis and a stabilometric analysis of the handstand (classical analysis and non-linear analysis). Results of these analyzes suggest different strategy according to visual field dependence in the control of the handstand, which does not seem to be the case in upside-down posture

Thèse en cotutelle internationale avec l'Université de Caen Normandie en France / La réalité virtuelle s’est imposée comme un nouveau paradigme de la recherche et des applica-tions scientifiques. La capacité de cette technologie à simuler des situations complexes sur me-sure offre aux chercheurs la possibilité d’étudier des comportements possédant contrôle méthodo-logique et dimension écologique. Cette dernière est rendue possible par l’émergence du sentiment de présence, la sensation « d’être là », phénomène au cœur des études in virtuo. Le présent tra-vail s’inscrit dans un cadre méthodologique et fondamental visant à faire avancer l’émergence d’un corps de connaissances sur la réalité virtuelle et son sentiment de présence. En effet, la compréhension globale de ce dernier demeure très limitée, notamment au regard de ses liens avec la performance en réalité virtuelle. Que ce soit dans un but de diagnostic ou d’investigation du comportement humain, la question de la relation entre sentiment de présence et performance est pourtant cruciale : si la présence favorise la performance, par exemple la performance à un test neuropsychologique, celle-ci devient un biais systématique inhérent à l’outil qu’il est néces-saire de contrôler pour toute expérimentation rigoureuse. Si cette question demeure peu étudiée dans la littérature c’est parce qu’elle est largement complexifiée par les interactions entre tout un ensemble de variables adjacentes – genre, cybermalaises, style cognitif, expérience des jeux vi-déo –, mais aussi parce que la performance peut prendre des myriades de formes différentes et qu’il est ainsi particulièrement ardu d’inférer une causalité directionnelle. Afin d’explorer cette question, le présent travail propose trois expérimentations sur trois différents types d’évaluation : fonctions exécutives, cognition spatiale, apprentissage sémantique. Les données ainsi recueillies font également l’objet d’analyses transversales destinées à comparer les expérimentations. En-semble, ces résultats semblent distinguer l’existence de deux composants de la réalité virtuelle. Le premier, le profil cognitif, est constitué par les facteurs humains individuels interagissant avec les facteurs systèmes – notamment le degré d’intégration de la tâche – pour moduler le deu-xième, l’expérience utilisateur. De cette expérience utilisateur dépendent le sentiment de pré-sence, la performance, mais aussi leur relation. Ce modèle, présenté en conclusion, est discuté au regard d’approches théoriques différentes de la cognition et permet de dresser une liste de recommandations et de perspectives pour les utilisateurs de la réalité virtuelle, notamment les possibilités d’estimer a priori l’expérience utilisateur d’un individu. / Virtual reality has emerged as a new paradigm for research and scientific applications. The ability of this technology to simulate complex custom-made situations offers researchers the opportunity to study behaviours with a laboratory methodological control and an ecological dimensions. The latter is made possible by the emergence of the feeling (or “sense”) of presence, the sensation of "being there", a phenomenon at the heart of in virtuo studies. The present work is part of a meth-odological and fundamental framework aimed at advancing the emergence of a body of knowledge on virtual reality and its sense of presence. The global understanding of the sense of presence remains very limited, especially with regard to its links with performance in virtual reality. Whether it is for diagnostic purposes or for the investigation of human behaviour, the question of the relationship between the sense of presence and performance is crucial: if presence promotes performance, for example by increasing scores during a neuropsychological test, it becomes a systematic bias inherent to the tool that must be controlled in any rigorous experiment. This ques-tion remains little studied in the literature, mostly because it is complexified by the interactions between a whole set of adjacent variables – gender, cybersickness, cognitive style, video game experience – but also because performance can take many different forms, making it particularly difficult to infer directional causality. In order to explore this question, the present work proposes three experiments on three different types of evaluation: executive functions, spatial cognition, semantic learning. The data collected in this way is also the object of transversal analyses de-signed to compare the experiments. Together, these results seem to suggest the existence of two components of virtual reality. The first, the cognitive profile, is made up of individual human factors interacting with system factors – notably the degree of integration of the task into the virtual envi-ronment – to build the second, the user experience. The sense of presence and performance, but also their relationship depends on the user experience. This model, presented in conclusion, is discussed with regard to different theoretical approaches to cognition, notably the ecological and computational theories. This discussion makes it possible to draw up a list of recommendations and perspectives for virtual reality users, including the possibilities of estimating a priori the user experience of an individual immersed in virtual reality.