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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.
21

Structure-function relationships in cellular copper control

Zhang, Limei 09 June 2009 (has links)
X-ray absorption spectroscopy and computational chemistry have been used to probe the structure of biomolecules involved in cellular copper homeostasis. X-ray absorption spectroscopy shows that copper chaperones involved in cytochrome c oxidase assembly bind Cu(I) with trigonal coordination environments in poly-copper thiolate clusters, but the number of coppers in these clusters remains unclear. X-ray absorption spectroscopy of the metal-sensing transcription factor-1 from Drosophila melanogaster and metallothionein from Saccharomyces cerevisiae with stoichiometries of four or less shows a tetracopper cluster in an all-or-none manner in these molecules. These results suggest that cooperative binding of copper to form tetracopper clusters may be a common mechanism employed by copper control molecules. The active site structure of the novel copper-sensitive repressor CsoR in Mycobacterium tuberculosis binds copper in a trigonal coordination geometry with two sulfur and one nitrogen donors according to X-ray absorption spectroscopy results. Molecular dynamics simulations of both apo- and Cu-bound CsoR reveal local conformational changes in CsoR upon copper binding, which suggests multiple possible mechanisms of Cu-dependent transcriptional regulation by CsoR. Finally, X-ray absorption spectroscopy and X-ray fluorescence imaging have been used to understand the molecular basis of a promisng new treatment for Wilsons disease (a genetic disorder of Cu homeostasis) using tetrathiomolybdate. Overall, the results presented provide an essential structural basis for understanding copper homeostasis in living cells.
22

Investigação de qualidade para comparação de sistemas de imagem em radiologia odontológica / Quality investigation in order to compare odontologic radiographic image systems

Hamilton Baptista da Costa 28 November 2005 (has links)
O presente trabalho de pesquisa trata da investigação de parâmetros de qualidade aplicados a sistemas de imagem em radiologia odontológica. Para isso, foram levantados parâmetros propostos pela Portaria nº 453 de 1998 da Secretaria de Vigilância Sanitária do Ministério da Saúde em aparelhos de raios X odontológicos e determinadas funções de transferência de modulação (FTM), como método para a avaliação da resolução espacial de sistemas de radiologia odontológica digital. Com base nesses dados, comparou-se três sistemas digitais diretos (DIGORA, DENOPTIX e CygnusRay) e um sistema digital indireto, baseado no scanner Umax PowerLook 1120. Essa comparação evidenciou, para esse caso, a melhor qualidade, em termos de resolução espacial, do sistema indireto estudado e a relativa equivalência dos sistemas digitais entre si, quando comparados em suas resoluções máximas (em número de pontos por polegada). Também foi possível validar o uso do método de simulação computacional para a obtenção da FTM de sistemas radiográficos odontológicos / This work has investigated quality parameters applied to odontologic radiographic image systems. In order to achieve this purpose, parameters related to the Portaria nº 453 of 1998 of Secretaria de Vigilância Sanitária do Ministério da Saúde have been checked and modulation transfer functions (MTF) have been determined. These information has been used to compare three differents direct radiographic images systems (DIGORA, DENOPTIX e CygnusRay) and one indirect, based on scanner Umax PowerLook 1120. The obtained data has showed, in this case, the better performance, in terms of spatial resolution, of the indirect system and the relative equivalency of the direct systems, when configured with the maximum resolution (in term of dpi). The work has validated the computer simulation process in order to generate the MTF of odontologic radiographic image systems
23

Ajustements de fonctionnelles de Skyrme généralisées / -

Jodon, Robin 26 September 2014 (has links)
La méthode de la fonctionnelle de la densité d’énergie (Energy Density Functional, EDF) est une approche phénoménologique permettant de calculer les propriétés élémentaires des noyaux atomiques (masses, dimensions et formes) a l’approximation du champ moyen. Elle permet également d’obtenir les spectres correspondant à certains états collectifs (vibrationnels et rotationnels) en mettant en œuvre des calculs ≪ au-delà ≫ du champ moyen (avec la méthode de la coordonnées génératrice (GCM) ou le mécanisme de brisure/restauration de symétries). Cette méthode, applicable sur toute la charte des noyaux hormis les plus légers, connait un regain d’intérêt avec le développement de nouveaux faisceaux radioactifs tels SPIRAL2 au GANIL. Des travaux récents ont montré qu’une description des états collectifs des noyaux nécessitait la modification et la généralisation des formes habituellement utilisées pour la fonctionnelle de la densité d’énergie, notamment avec la suppression de termes dépendants de la densité. Il a également été montre que les fonctionnelles de Skyrme pouvaient conduire à des instabilités et transitions de phases non physiques dans la matière nucléaire et les noyaux, en particulier lorsque le système est autorisé à briser des symétries. Le but de ce travail de thèse a été d’achever la construction de la fonctionnelle de Skyrme généralisée, initiée par J. Sadoudi (Constraints on the nuclear energy density functional and new possible analytical forms., CEA Saclay, 2011), puis d’en ajuster les paramètres. Le terme dépendant de la densité est remplacé par un potentiel d’interaction à 3 et 4 corps et la fonctionnelle associée est utilisée pour décrire le champ moyen et le champ d’appariement. Il a été nécessaire de construire un nouveau protocole d’ajustement afin de contraindre les paramètres de cette fonctionnelle. En particulier, l’ajustement est fait avec des contraintes sur les instabilités précédemment mentionnées. Parallèlement a la construction du protocole d’ajustement, l’utilisation de techniques d’analyse covariante a permis, dans un premier temps, d’estimer les erreurs statistiques associées a chaque paramètre ajuste et les barres d’erreurs des observables calculées. Dans un second temps, nous avons étudié les corrélations existantes entre les différentes contraintes choisies dans le protocole, ce qui a permis de mettre en évidence certains défauts de ces nouvelles interactions généralisées. Enfin, dans un travail annexe, nous avons utilisé des méthodes semiclassiques de type Thomas-Fermi modifiées (MTF) afin de dériver une formule analytique permettant d’estimer la valeur du coefficient d’énergie de surface d’une interaction de Skyrme généralisée. En réajustant les paramètres de la fonctionnelle SLy5 avec une contrainte sur ce coefficient, nous avons montré qu’il était fortement corrèle aux propriétés de fission des actinides. Nous aurons ainsi à notre disposition, grâce à cette estimation du coefficient d’énergie de surface, un outil simple à mettre en œuvre dans des protocoles d’ajustements futurs qui permettra de contraindre les propriétés de fission des noyaux / -
24

Signal to Noise Ratio Effects on Aperture Synthesis for Digital Holographic Ladar

Crotty, Maureen January 2012 (has links)
No description available.
25

According to whose will : The entanglements of gender & religion in the lives of transgender Jews with an Orthodox background

Poveda Guillén, Oriol January 2017 (has links)
This study, the first in its scope on transgender religiosity, is based on in-depth biographical interviews with 13 transgender participants with a Jewish Orthodox background (currently and formerly Orthodox). The primary aim of the study has been to elucidate the entanglements of gender and religion in three periods of the participants’ lives: pre-transition, transition and post-transition. One of the main topics investigated have been the ways participants negotiated gendered religious practices in those three periods. A secondary aim of this study has been to co-theorize, in dialogue with the participants, different possible paths for religious change; that is, the ways in which the larger Orthodox community might respond to the presence of openly transgender members in its midst. Concerning the findings, in the course of this study I have developed the themes of dislocations and reversal stories to explain how the participants negotiated the entanglements of gender and religion particularly in the transitional and post-transitional periods. The latter theme–reversal stories–has been of special relevance to explain how gendered religious practices, which were generally detrimental to the acceptance of the participants’ gender identities during the pre-transitional period, had the potential to become a powerful source for gender affirmation after transition. In this study I argue that this possibility and its related mode of agency are not contained within the binary resistance/subordination that feminist scholars have developed to account for the agency of women in traditionalist religions. In order to better conceptualize the notion of agency and explore the nature of the mutual entanglements of gender and religion, I deploy the body of theoretical work developed by Karen Barad known as agential realism. Lastly, I conclude by examining my initial commitments to social constructionism (in Peter Berger’s definition). In the final chapter, I describe how in the course of my study I have encountered three unexpected sites of resistance to social constructionism that have led me to reconsider my previous epistemological commitments and embrace posthumanism as a more satisfactory alternative. / The Impact of Religion - Challenges for Society, Law and Democracy
26

Evaluation of night vision devices for image fusion studies

Cheng, Wee Kiang 12 1900 (has links)
Approved for public release; distribution in unlimited. / Night Vision Devices (NVD) using Image Intensification (II) technology are among the most important sensors used by ground troops and aviators in night operations for modern combat. With the intensified images from these devices, soldiers can see an enemy's movement better and further in darkness. This thesis explores different test methods in evaluating the performances and sensitivities of several NVDs for future image fusion studies. Specification data such as sensitivity, resolution (Modulation Transfer Function) and pixel size are obtained. Comparative analyses of the collected results are made to characterize the performances of the different NVDs. A new method using MATLAB programming to objectively analyze digitized images for characterization of II based NVDs is proposed. This test method can also be extended to the evaluation of Thermal Imaging (TI) systems for comparative analysis with II NVDs. In addition, the feasibility of testing NVDs using both II and TI technologies, with common operating conditions and target boards is discussed. Finally, the potential of using these digitized images for image fusion studies is verified with the test and evaluation results. / Republic of Singapore
27

FTM Trans Theory VS. Trans Narratives : Working Towards an Updated Trans Theory

Nelson, Emily January 2011 (has links)
Theories are tools with which we critically analyze society‟s structure and understand experiences that are not our own. When theories no longer describe the narratives that they claim, we must update them. This thesis proposes to do just that. The trans theories of J. Halberstam and Jay Prosser will be analyzed using ten autobiographies written by self-identified FTM transsexuals and transmen. Prosser and Halberstam are two well-known theorists in the field of trans theory. J. Halberstam approaches FTM transsexuality from the perspective of a lesbian feminist, who has an understanding of transgender butch individuals. Jay Prosser writes from the perspective of being a FTM transsexual himself. I chose publications by these theorists because they had sections that focused specifically on FTM narratives, and they both used at least two of the autobiographies I use and they were published the same year. Therefore, I found them to be two theoretical frameworks that could be compared on several different levels. The publication dates of the ten narratives range from the 1970s to the early 2000s. Applicability of the theories will be measured by comparing them to what the autobiographers say about their lives. The tool of analysis will be five focus areas that are represented, to some degree, in each narrative. They are: Trying to fit into female roll/body/world; Discovering one is Trans/Coming Out; Acquiring Hormones and Sexual Reassignment Surgery; Trying to Establish/Re-establish a Confident Identity; and Romantic/Sexual Relationships.. I will discuss how helpful each theory is in accordance with these narratives. The aim of this thesis is to assess how well each theorist addresses the issue of transsexual identity. The field of transsexual research is still new and developing, there are many interesting parts of these narratives that can be delved into further. I will conclude by proposing a new trans theoretical view point that would better help one to understand the process of female-to-male transition. What one should take away from this thesis is that despite differences in sex and gender formation, these people are, like the rest of the world, trying to create an identity that they not only feel comfortable with as a representation of themselves, but also one that they can be proud of.
28

Obrazové detektory rentgenového záření pro aplikace v microCT systémech / X-ray Image detectors for using in microCT systems.

Papajová, Gabriela January 2017 (has links)
Diplomová práce se zabývá detektory rentgenového záření pro mikro-CT systémy. Teoretická část zahrnuje standartní typy rentgenových detektorů a požadavky na kvalitu obrazu pro výslednou 3D rekonstrukci. V závěru jsou popsány fyzikální parametry reálných detektorů a metody jejich měření a vyhodnocení.
29

Nyintroduktioner på svenska handelsplatser : Har nyintroduktioner genererat högre avkastning än NASDAQ OMXSPI? / Initial Public Offerings on Swedish marketplaces : Have IPOs created higher returns than NASDAQ OMXSPI?

Karpov, Boris, Klevenstedt, Johan January 2011 (has links)
Denna studie har genomförts i syfte att undersöka huruvida nyintroduktioner generar en överavkastning i förhållande till OMXSPI på svenska handelsplatser under en börsuppgång och en börsnedgång för olika tidsintervall och branscher. Studien har undersökt nyintroduktioner genomförda under tidsperioden Q1 2004 till Q2 2009. Syftet har för avsikt att utmynna i huruvida nyintroduktioner vid svenska handelsplatser är effektiva och om investerare kunnat utnyttja eventuella ineffektiviteter som investeringsstrategier. Undersökningen är en eventstudie baserad på en kvantitativ metod där korrigerade historiska aktiekurser har inhämtats och beräkningar har genomförts med hjälp av två metoder, den genomsnittliga abnormala avkastningen och den genomsnittliga abnormala avkastningen för en buy-and-hold strategi, för att säkerställa en hög validitet i studien. Slutsatsen påvisar att investerare som investerat i nyintroduktioner på AktieTorget under börsuppgången hade kunnat utnyttja den något lägre grad av effektivitet utifrån en buy-andhold strategi på tre månader och erhållit en genomsnittlig signifikant överavkastning gentemot OMXSPI på 32,6 procent. En investerare som valt att investerare i nyintroduktioner utifrån en buy-and-hold period på tre månader på Alternativa Aktiemarknaden under börsnedgången hade i genomsnitt erhållit en signifikant överavkastning på 11,8 procent. För den investeraren som inte tagit hänsyn till när introduktionen genomförts och investerat i nyintroduktioner på AktieTorget utifrån en buy-and-hold period på en månad hade i genomsnitt erhållit en signifikant överavkastning på 18,2 procent.
30

”Jag är inte här för att utbilda dig, jag är här för att jag behöver din hjälp.” : En kvalitativ intervjustudie om transpersoners erfarenheter av bemötande från samhällets instanser. / ”I’m not here to educate you, I’m here because I need your help.” : A qualitative study of transgender people's experience of treatment by institutions within society.

Rydbjer, Beatrice, Bristav, Karin January 2017 (has links)
This is a qualitative interview study where 7 transgender people is interviewed about their experiences of treatment from institutions within society. In semi-structured interviews, respondents talk about the treatment they received from health care, education, legal system, employment offices and social services. The study's purpose is to examine the treatment transgender peoples gets based on their own stories and perspectives. The study also discusses the social structures, like binary gender norms, that contribute to a negative attitude and the consequences of this approach. The result shows that there is a great lack of knowledge within institutions and professionals have insufficient training in how to treat people with transgender identities. Respondents have often had to educate professionals and carries their identity as a backpack that they can not get rid of. The results also indicate that the prevailing social structures that divide people in binary gender norms is problematic for transgender people. / Detta är en kvalitativ intervjustudie där 7 transpersoner intervjuats om deras erfarenheter av bemötande från samhällets instanser. I semistrukturerade intervjuer har respondenterna berättat om det bemötande de fått från vården, utbildning, rättsväsendet, arbetsförmedlingen och socialförvaltningen. Studiens syfte är att undersöka bemötande transpersoner får utifrån deras egna berättelser och perspektiv. I studien diskuteras även samhällsstrukturer, såsom tvåkönsnormen, som bidrar till ett negativt bemötande samt konsekvenserna av detta bemötande. Resultatet visar att det råder en stor kunskapsbrist inom samhällets instanser och professionella har bristande utbildning i hur de ska bemöta personer med könsöverskridande identiteter. Respondenterna har ofta fått agera utbildare för professionella och bär med sig sin identitet som en ryggsäck som de inte kan bli av med. Resultatet pekar också på att rådande samhällsstrukturer som delar in personer i en tvåkönsnorm är problematisk för transpersoner.

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