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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
141

The Last Council: Social Security Policymaking as Coalitional Consensus and the 1994-1996 Advisory Council as Institutional Turning Point

Gibson, James Edward 26 July 2007 (has links)
This dissertation traces Social Security policymaking through most of its post-enactment history in search of ideational processes and schema in path-dependent, path-shaping, and path-breaking modes of institutional persistence and change. The study is grounded in the historical institutionalist literature, specifically the recent debate about the utility of path dependence frameworks in incorporating institutional change, with a particular focus on ideas as stimuli. As a case for tracing path-dependent policy processes, Social Security is overbroad. This breadth requires focusing more narrowly on the interaction between the major coalitions, business/conservative and liberal/labor, on retirement and disability pension (but not health care) issues through the venue of Social Security Advisory Councils. Council is used as a catch-all label for the six-decade succession of (mostly) citizen groups appointed by the secretary of HEW, Senate Finance Committee, and, in one case, the president to deliberate questions of Social Security policy and recommend changes, often enacted into law. A pattern-matching analysis points to a moderate level of path dependence, indicating that the exchange of ideas between coalitions fits the larger consensual pattern of give and take around an existing arrangement. An ideational narrative reveals early negotiations over the emphasis placed on equity versus adequacy, with manifestly ideational exchanges in the 1996 Council's deliberations marking a turning point in the coalitional interaction. A key implication of this research for the application of path dependence frameworks to U.S. political institutions like Social Security is to buttress moderate path dependence arguments, for instance, those advanced by Hacker and Pierson (2002), and to discount the relevance of path-shaping narratives that have been fashioned from European examples (Cox 2004). Yet the research also modifies understanding of path dependence as a self-perpetuating function of increasing returns by identifying an ideational strand that bound both coalitions to social insurance principles. Path-breaking developments apparent in the 1996 Council further implicated new ideas as institutional factors contributing to the loss of historical consensus on Social Security, bolstering the notion of ideational processes as an element of institutional persistence and pressing the argument for further research into ideas as dynamic elements fostering institutional change. / Ph. D.
142

Investigation of the Effects of an Autostereographic Virtual Environment on Recall in Participants of Differing Levels of Field Dependence

Moore, Michael Wilson 14 April 2006 (has links)
Stereographic virtual environments display data in such a way that a user perceives objects within the displayed environment to be separated in depth from the display itself. The effectiveness of stereographic virtual environments as learning tools has been evaluated relative to factors such as multidimensional cues, user interaction, and learner characteristics. This study has examined the relationship between two evaluative factors: the presence of stereographic depth cues and field dependence, a learner characteristic associated with performance on visual tasks. Adult learners were identified on a field dependence continuum based on scores on the Group Embedded Figures Test. Each student received instruction related to the heart using stereographic materials or nonstereographic materials, depending on assignment to treatment group. All participants were given two tests, identification and terminology, following this instruction. The scores on the combination of these tests, denoted as the Modified Total Criterion Test (MTCT), represented the level of visual recall relative to the instructional materials reviewed. Analyses of variance revealed an interaction effect between the level of field dependence and the presence of stereographic depth cues within a virtual environment such that field independent participants scored higher on tests of visual recall within stereographic conditions versus nonstereographic conditions and field dependent participants scored lower within stereographic conditions versus nonstereographic conditions. / Ph. D.
143

Assessing performance and compatibility of three Laricobius species as predators of hemlock woolly adelgid, Adelges tsugae

Story, Heather Marie 20 May 2010 (has links)
Predation, egg production and survivorship of Laricobius nigrinus Fender, L. rubidus, LeConte, and L. osakensis Montgomery and Shiyaki (proposed), predators of hemlock woolly adelgid, Adelges tsugae, Annand, were investigated in the laboratory and in the field. In individual assays, L. rubidus oviposited fewer eggs than either L. nigrinus or L. osakensis. In assays containing congeneric or conspecific groups of adult Laricobius, L. osakensis preyed upon the greatest number of ovisacs. When all three species were together, the numbers of ovisacs preyed upon were similar to the mean of all three individual species. Adult predators fed on few eggs and did not exhibit any species preference. The numbers of A. tsugae ovisacs fed upon did not differ significantly by groups of congeneric or conspecific Laricobius larvae. Laricobius adults and larvae had high survival rates throughout all experiments. In the field, predators were enclosed in sleeve cages with both high (> 120 ovisacs) and low (< 90 ovisacs) A. tsugae densities for 1 wk. All branches with caged beetles had significantly greater numbers of ovisacs preyed upon than branches caged without beetles. No differences in predation or egg production were found among the conspecific and congeneric groupings. Predation was uniformly higher at the high prey-density than at the low prey-density. Survivorship among predators did not differ significantly at either prey density. Results from both laboratory and field experiments suggest that these species are able to co-exist and can be in the same location for biological control of A. tsugae. / Master of Science in Life Sciences
144

Atomic clusters in intense laser fields

Springate, Emma Louise January 1999 (has links)
No description available.
145

Ultrasonic wave interactions with magnetic colloids

Chapman, John Richard January 2001 (has links)
No description available.
146

Humidity dependent impedance of Zn(_x)Co(_2-x)GeO(_4)

Hales, Debbie January 1999 (has links)
Zn(_x)Co(_2-x)GeO(_4) materials were prepared and the variation in structure with composition was investigated using XED, SEM and EDX analysis. Limited series of solid solution were identified at both ends of the compositional range. D C electrical measurements were carried out to characterize the variation in the resistivity of the materials with humidity. Resistivities of the order of 10(^8) Ω m were observed in dry conditions, decreasing by 4 to 5 orders of magnitude with increasing humidity. Resistivity was not found to vary greatly with composition. Resistivity was temperature dependent, increasing by 1 to 2 orders of magnitude for a 70 C decrease in temperature. A C impedance measurements were performed to gain an understanding of the mechanism of the humidity dependent conductivity. At low frequencies impedance was found to be independent of frequency and humidity dependent. At high frequencies impedance was found to be inversely proportional to frequency and independent of humidity. The break point frequency was also humidity dependent and an increase in the impedance indicated inductive-type behaviour. Complex plane representation of the impedance gave a distorted semicircle at high frequencies and a low frequency tail. At high humidities the tail appears as a straight line, inclined at approximately 45 . At medium levels of humidity a distinctive loop is apparent at the intersection between the semicircle and the tail, corresponding to the inductive behaviour indicated at the break point frequency. The impedance response was modelled by an equivalent circuit consisting of various ideal and constant phase (dispersive) elements. The proposed mechanism of humidity-dependent conductivity is due to chemisorption and physisorption of water vapour from the atmosphere at the surface of the material, It is suggested that conduction occurs by hopping of protons between cheraisorbed hydroxyl groups at low humidities, by diffusion of H(_3)O(^+) ions between the hydroxyl groups at intermediate humidities and by hopping of protons between physisorbed H(_3)O(^+) ions (Grotthus Chain reaction) at high humidities.
147

Regionální rosvoj a inspirace z jiných disciplin : možnosti aplikace konceptů evoluční biologie na vybraná témata regionálního rozvoje / Le développement régional et l’inspiration puisée dans d’autres disciplines : les possibilités de l’application des concepts de la biologie évolutionnaire aux sujets sélectionnés du développement régional / Regional development and inspiration from other disciplines : Possibilities of application of evolutionary biology concepts to the selected themes of regional development

Jungwiertová, Lucie 19 January 2010 (has links)
L’application des concepts de la biologie évolutionnaire (BE) à la problématique de la réalité socioéconomique n’est pas un sujet nouveau dans certaines disciplines socioéconomiques, même si cette inspiration pour la problématique de la géographie socioéconomique, ou plutôt du développement régional, est plus récente et en général se fonde sur les applications réalisées notamment en économie. L’objectif principal de cette thèse est d’identifier de nouveaux concepts de la BE et de tenter de les appliquer aux sujets sélectionnés du développement régional directement, sans le rôle d’intermédiaire d’autres disciplines. L’attention est dans un premier temps prêtée à la recherche du cadre théorique convenable et d’un aperçu des concepts de la BE déjà appliqués aux sciences sociales. La seconde partie présente certains concepts de la BE pour lesquels les applications potentielles (par l’intermédiaire des analogies et des métaphores) aux thèmes choisis du développement régional ont été identifiées. Les concepts appliqués ont été divisés en quatre ensembles thématiques biologiques plus larges – l’adaptation, la coévolution, la sélection et la spéciation. L’application de la spéciation peut être probablement perçue comme la contribution la plus précieuse de la thèse. Elle s’appuie sur l’hypothèse qu’il est possible d’identifier certains traits analogues entre les concepts socioéconomiques path dependence et lock-in et les concepts de la BE concernant la spéciation et d’identifier et de classifier les mécanismes / structures qui fonctionnent comme des barrières socioéconomiques. / Application of the evolutionary biology concepts to socio-economic reality issues is not any new theme, even if this inspiration in socio-economic geography and especially in regional development is more recent and is based, in general, on already realized applications, mainly in economics. The main objective of the PhD thesis is thus an identification of hitherto non-applied evolutionary concepts, or to this time neglected biological aspects of already applied concepts and an attempt of their application to the selected themes of regional development without the intermediary role of other disciplines. In the first place, the attention is paid to the search of an appropriate theoretical approach and of the summary of already applied evolutionary concepts to the social sciences. Second part presents some evolutionary biology concepts where a potential for applications (based on the mediator role of analogies and metaphors) to the selected regional development issues was identified. Individual applied concepts were divided into four more complex thematic units – adaptation, co-evolution, selection and speciation. The application of the last concept could probably be considered as the most valuable contribution of the PhD thesis. It is based on the hypothesis that some analogical traits can be identified among socio-economic concepts of path dependence and lock-in and biological concepts linked with speciation and that the biological concepts can provide the general inspiration for identification of certain types of socio-economic barriers of development of regions and for an attempt to classify them.
148

Energie, territoire et Path dependence : enjeux spaciaux et territoriaux d'une déclinaison régionale de la transition énergétique en Provenc-Alpes-Côte d'Azur / Energy, territory and Path dependence : spatial and territorial challenges of a regional version of energy transition in Provence-Alpes-Côte d'Azur

Chabrol, Maximin 21 October 2016 (has links)
La transition énergétique est un projet de société qui impose un modèle énergétique durable marquant le passage d’une économie énergivore largement basée sur les ressources fossiles à une économie plus sobre en énergie et fondée sur un mix garantissant un niveau de performance économique au moins équivalent à celui d’aujourd’hui, l’économie bas-carbone. Alors que dans le passé, les transitions énergétiques étaient des processus intégrés à l’évolution générale des sociétés par les progrès techniques, la transition énergétique d’aujourd’hui est un processus nettement engagé à l’initiative des pouvoirs publics, particulièrement en Europe. Ce changement énergétique implique l’adaptation des territoires à des modes de fonctionnement moins énergivores et de développer des productions d’énergie renouvelable. Cette thèse répond à un double questionnement géographique. Quelles sont, pour l’organisation de l’espace et le fonctionnement des territoires, les implications de ce changement énergétique ? Quels sont les influences et rôles de l’organisation spatiale et des territoires sur le changement énergétique ? La transition énergétique est ici considérée comme un processus fondamentalement géographique qui implique la remise en cause des configurations spatiales actuelles de l’activité économique et sociale, et que l’on examine ainsi comment espace et territoire y répondent, s’y adaptent, la contraignent ou l’accélèrent. Cette thèse saisit plus précisément les enjeux d’une déclinaison régionale de la transition énergétique en révélant les contraintes spatiales et territoriales qui l’encadrent et la déterminent. En s’appuyant sur des travaux d’analyse spatiale et de traitement de données, les dimensions spatiale et territoriale du concept de Path dependence sont développées dans le cadre d’une analyse régionale en Provence-Alpes-Côte d’Azur. Trois domaines de la dimension spatiale de la transition énergétique comme élément relevant de la Path dependence sont abordés : l’influence des structures spatiales et la dépendance au lieu ou material lock-in, la territorialisation et le développement durable inégal ou territorial lock-in, et le poids des structures socio-spatiales héritées ou socio-spatial lock-in. La transition énergétique n’est pas seulement une question économique et politique et l’espace n’est pas seulement un facteur de différenciation spatiale de ce processus. L’espace des sociétés contient aussi des principes d’évolution qui engagent une logique de Path dependence. Toute la complexité de la transition énergétique réside alors dans la complexité spatiale et territoriale qui l’encadre et la détermine, celle de l’organisation des hommes dans l’espace. / The energy transition is a society project that imposes a sustainable energy model marking the shift from an energy economy based largely on fossil fuels to a more efficient economy based on an energy mix ensuring a level of economic performance at least equivalent to the actual situation today, the low-carbon economy. While in the past, energy transitions were integrated processes to the general evolution of societies by technological advances, today's energy transition is a process clearly committed to the initiative of the authorities, especially in Europe. This energy change involves the adaptation of territories to less energy-intensive modes and to develop renewable energy production. This thesis has a dual geographical questioning. Which, for the space organization and functioning of the territories, the implications of this energy change? What are the influences and roles of the spatial organization and territories on the energy change? The energy transition is here seen as a basically geographical process that involves the questioning of current spatial patterns of economic and social activity, and which can thus examine how space and territory meet it, adapt to it, forcing it or accelerating it. This thesis captures more precisely the issues of a regional version of the energy transition by revealing the spatial and territorial constraints that frame and determine. Building on the work of spatial analysis and data processing, spatial and territorial dimensions of the concept of Path dependence are developed as part of a regional analysis in Provence-Alpes-Côte d'Azur. Three areas of the spatial dimension of the energy transition as an element of Path dependence are studied: the influence of spatial structures and place dependence or material lock-in, territorialization and uneven sustainable development or territorial lock-in, and the weight of inherited socio-spatial structures or socio-spatial lock-in. The energy transition is not only an economic and political issue, and space is not only a spatial differentiation factor in this process. The geographical space also acquired its principles of evolution that involve logic of Path dependence. The complexity of the energy transition is in the spatial and territorial complexity that surrounds and determines the organization of humanity into space.
149

Estudo da resposta de monitores de radioproteção em feixes padronizados de radiação X, gama e beta. / Study of radiation detectors response in standard X, gamma and beta radiation beams

Fernanda Beatrice Conceição Nonato 24 May 2010 (has links)
Foram estudadas as respostas de 76 detectores Geiger-Müller, 4 detectores semicondutores e 34 câmaras de ionização. Muitos deles foram calibrados em feixes de radiação gama (37Cs e 60Co) e alguns foram testados em feixes de radiação beta (90Sr+90Y e 204Tl) e X (N-60, N-80, N-100, N-150). Para os três tipos de radiação, foram obtidos os fatores de calibração dos instrumentos e foi estudada a dependência tanto energética como angular destes detectores. Para radiação gama e beta foi estudada a dependência angular para ângulos de 00 e ± 450. Foram ainda obtidas as curvas da resposta dos instrumentos em relação a uma varredura angular de 00 e ± 900, para radiação gama, beta e X. Também foram analisados os fatores de calibração obtidos para radiação beta em relação à radiação gama. Para radiação gama, dos 66 detectores Geiger-Müller estudados, 24 apresentaram resultados para a dependência energética de acordo com a recomendação internacional da ISO 4037-2 e 56 estão de acordo com a recomendação brasileira da ABNT 10011. As câmaras de ionização e os semicondutores estão de acordo com as recomendações nacional e internacional. Todos os instrumentos apresentaram dependência angular menor que 40%. Para radiação beta, os instrumentos apresentaram resultados insatisfatórios para a dependência energética e angular; Para radiação X, as câmaras de ionização apresentaram resultados para dependência energética de acordo com a recomendação nacional, e a dependência angular foi menor que 40%. / The response of 76 Geiger-Müller detectors, 4 semiconductor detectors and 34 ionization chambers were studied. Many of them were calibrated with gamma radiation beams (37Cs and 60Co), and some of them were tested in beta radiation (90Sr+90Y e 204Tl) and X radiation (N-60, N-80, N-100, N-150) beams. For all three types of radiation, the calibration factors of the instruments were obtained, and the energy and angular dependences were studied. For beta and gamma radiation, the angular dependence was studied for incident radiation angles of 00 and ± 450. The curves of the response of the instruments were obtained over an angle interval of 00 to ± 900, for gamma, beta and X radiations. The calibration factors obtained for beta radiation were compared to those obtained for gamma radiation. For gamma radiation, 24 of the 66 tested Geiger-Müller detectors presented results for the energy dependence according to international recommendation of ISO 4037-2 and 56 were in accordance with the Brazilian ABNT 10011 recommendation. The ionization chambers and semiconductors were in accordance to national and international recommendations. All instruments showed angular dependence less than 40%. For beta radiation, the instruments showed unsatisfactory results for the energy dependence and angular dependence; For X radiation, the ionization chambers presented results for energy dependence according to the national recommendation, and the angular dependence was less than 40%.
150

Estudo da resposta de monitores de radioproteção em feixes padronizados de radiação X, gama e beta. / Study of radiation detectors response in standard X, gamma and beta radiation beams

Nonato, Fernanda Beatrice Conceição 24 May 2010 (has links)
Foram estudadas as respostas de 76 detectores Geiger-Müller, 4 detectores semicondutores e 34 câmaras de ionização. Muitos deles foram calibrados em feixes de radiação gama (37Cs e 60Co) e alguns foram testados em feixes de radiação beta (90Sr+90Y e 204Tl) e X (N-60, N-80, N-100, N-150). Para os três tipos de radiação, foram obtidos os fatores de calibração dos instrumentos e foi estudada a dependência tanto energética como angular destes detectores. Para radiação gama e beta foi estudada a dependência angular para ângulos de 00 e ± 450. Foram ainda obtidas as curvas da resposta dos instrumentos em relação a uma varredura angular de 00 e ± 900, para radiação gama, beta e X. Também foram analisados os fatores de calibração obtidos para radiação beta em relação à radiação gama. Para radiação gama, dos 66 detectores Geiger-Müller estudados, 24 apresentaram resultados para a dependência energética de acordo com a recomendação internacional da ISO 4037-2 e 56 estão de acordo com a recomendação brasileira da ABNT 10011. As câmaras de ionização e os semicondutores estão de acordo com as recomendações nacional e internacional. Todos os instrumentos apresentaram dependência angular menor que 40%. Para radiação beta, os instrumentos apresentaram resultados insatisfatórios para a dependência energética e angular; Para radiação X, as câmaras de ionização apresentaram resultados para dependência energética de acordo com a recomendação nacional, e a dependência angular foi menor que 40%. / The response of 76 Geiger-Müller detectors, 4 semiconductor detectors and 34 ionization chambers were studied. Many of them were calibrated with gamma radiation beams (37Cs and 60Co), and some of them were tested in beta radiation (90Sr+90Y e 204Tl) and X radiation (N-60, N-80, N-100, N-150) beams. For all three types of radiation, the calibration factors of the instruments were obtained, and the energy and angular dependences were studied. For beta and gamma radiation, the angular dependence was studied for incident radiation angles of 00 and ± 450. The curves of the response of the instruments were obtained over an angle interval of 00 to ± 900, for gamma, beta and X radiations. The calibration factors obtained for beta radiation were compared to those obtained for gamma radiation. For gamma radiation, 24 of the 66 tested Geiger-Müller detectors presented results for the energy dependence according to international recommendation of ISO 4037-2 and 56 were in accordance with the Brazilian ABNT 10011 recommendation. The ionization chambers and semiconductors were in accordance to national and international recommendations. All instruments showed angular dependence less than 40%. For beta radiation, the instruments showed unsatisfactory results for the energy dependence and angular dependence; For X radiation, the ionization chambers presented results for energy dependence according to the national recommendation, and the angular dependence was less than 40%.

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