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The Global ETD Search service is a free service for researchers
to find electronic theses and dissertations. This service is
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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.
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Showing 31 to 39 of 39 (0.008 seconds)| 31 |
Europa's Hydrogen Corona in a Large Set of HST Lyman-Alpha ImagesBergman, Sofia January 2017 (has links)
Far-ultraviolet (FUV) spectral images of Jupiter's moon Europa were obtained by the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope (HST) on 20 occasions between the years 1999 and 2015. In this thesis these data are analyzed to look for Lyman-alpha emissions from a hydrogen corona. This hydrogen corona was recently discovered in absorption, also from HST Lyman-alpha images but with Europa in transit of Jupiter, and the aim of this study is to confirm the existence of the corona also in emission. Europa's thin atmosphere is dominated by molecular oxygen, mainly produced by radiolysis and sputtering of the icy surface. Atomic hydrogen, the main target for this study, is produced by sputtering from the surface and the dissociation of H2 and H2O. It quickly escapes the gravity of Europa. To study the hydrogen corona in the spectral STIS images the data need to be processed to remove the other Lyman-alpha contributions to the image. These other contributions include emissions from the geocorona, emissions from the interplanetary medium (IPM), dark current in the detector and sunlight reflected from the surface of Europa. To estimate the contribution to the image from the hydrogen corona, a basic model of the expected emissions from the corona is developed. By fitting this model to the processed STIS data values of the hydrogen density and the surface Lyman-alpha albedo of the moon are obtained. The results confirm the presence of a hydrogen corona, with varying densities between the different observations but generally about twice as large as the results from the previous study. The uncertainty for the results is however large and there is a clear correlation between hydrogen density and background level in the image, for which the reason is poorly understood. No hemispheric variability or connections to the true anomaly of the moon are found, but the hydrogen density seems to be increasing during the time of the observations. The results for the albedo is consistent with previous results, indicating a lower albedo on the leading than on the trailing hemisphere.
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The Atmospheric SO2 Distribution and Volcanic Activity on IoKurenko Landin, Roman, Rana, Balwan January 2019 (has links)
Io is the innermost Galilean moon of Jupiter and is considered the most volcanically active body in our solar system. With the help of the Hubble Space Telescope’s (HST) on-board Space Telescope Imaging Spectrograph (STIS), far-ultraviolet (FUV) images of Io have been captured for the past 20 years. The final goal of this project is to study the sulphur dioxide (SO2) distribution and volcanic activity on Io in FUV data taken in 1997/98 and 2013/14. The method used concerns the conversion of spectral Lyman-α intensity to SO2 density using algorithms implemented in MATLAB. As a result the SO2 distribution and volcanic activity on Io were determined and compared between the data collections. We found that the SO2 was higher in the images from 1997/98 compared to 2013/2014.
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Who are the men in 'Men who have sex with men'?Manning, Elizabeth Joy 08 April 2010 (has links)
The term 'men who have sex with men' (MSM) as commonly used by HIV/AIDS researchers and policy makers is said to describe an obvious group of men. Or does it? While MSM disrupts the homosexual/heterosexual dichotomy through focusing on sexual practices rather than sexual identity, it remains entrenched in binary understandings of sex and gender. Influenced by queer and trans theories, a genderqueer methodology is employed to examine what discourses are deployed when MSM are categorized as a seemingly homogenous group. Who are the “men” in MSM and what are the material consequences of MSM discourse in HIV/AIDS work? Guided by feminist poststructural and Foucauldian theories, this study highlights how MSM discourse functions to exclude trans, intersex, and other non-normative sexed and gendered people while considering the potentially deadly effects of this discourse on those outside of MSM categorizations particularly focusing on its use in the Canadian Guidelines on STIs.
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Les Coeurs en Contre-RotationWernli, Fabien 28 November 2002 (has links) (PDF)
Les galaxies elliptiques ne sont des objets astronomiques très simples qu'en apparence: leur forme parfaitement régulière et ellipsoïdale est davantage le vestige d'une histoire tumultueuse semée d'interactions gravitationnelles avec d'autres galaxies plutôt que le signe d'un stade primitif dans leur vie. En effet, ces deux dernières décennies ont révélé la complexité de ces objets au niveau de leur cinématique interne, et surtout récemment avec le spectrographe intégral de champ SAURON qui a permis de dresser la structure bidimensionnelle de la vitesse de nombreuses galaxies elliptiques. La compréhension de la formation et de l'évolution de ces objets est un enjeu majeur de l'astrophysique contemporaine. La théorie hiérarchique de formation et d'évolution des galaxies, selon laquelle une galaxie est le résultat de nombreuses interactions et de fusions d'objets moins massifs, est à l'heure actuelle la mieux soutenue par les observations. Ainsi, elle permet de rendre compte de structures complexes telles les galaxies à coeur cinématiquement distinct, dans lesquelles on observe un brusque changement dans la courbe de rotation. Certains de ces objets montrent même une inversion dans le sens de rotation de la partie interne. De nombreuses études ont été réalisées pour comprendre les mécanismes de formation de ces coeurs, et la plupart d'entre elles semblent nécessiter l'apport d'un corps externe voire la fusion de deux galaxies. Dans ce travail nous réalisons dans un premier temps un catalogue de ces objets, afin d'en dégager les conclusions majeures. Dans un second temps nous présentons une méthode permettant d'extraire la signature orbitale de ces structures découplées en utilisant une modélisation dynamique de Schwarzschild . Nous appliquons cette méthode à trois objets dont nous disposons des données intégrales de champ, et tentons d'en extraire les principaux points communs. Finalement nous soulignons la valeur de cette méthodologie pour contraindre les modèles hiérarchiques de formation.
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Exploring factors that influence condom use among high school teenagers aged between 16 and 18 years in Dutywa District, Eastern Cape, South AfricaMnyipika, Nomandla 06 1900 (has links)
Text in English / The Department of Education nationwide introduced HIV and AIDS care and support for learning and teaching programmes as intervention strategies for supporting vulnerable learners. Despite these interventions, teenagers continue to fall pregnant and this increases their vulnerability to HIV infection. HIV and STIs are rife among teenagers owing to ignorance and peer pressure, among other factors. The aim of this exploratory qualitative study was to explore factors that influence condom use among high school teenagers aged between 16 and 18 in Dutywa District. Focus group discussions and in-depth face-to-face interviews with 12 high school teenagers from one high school (High School X) were used to collect data. Thematic analysis was used to analyse data. The findings of this study revealed that high school teenagers are not using condoms to any significant degree. In their opinion, condoms limit sexual pleasure; they indicate a lack of trust and unfaithfulness between partners and are associated with sexually transmitted diseases. The findings of this study are significant for the policy implementation of schools. / Sociology / M.A. (Social Behaviour Studies in HIV and AIDS)
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Let's talk (discreetly) about sex. The content generation and design of an online sexual and reproductive health information resource for young Vietnamese: a communications perspective.Clements, Alice Faith, alice.clements@rmit.edu.au January 2007 (has links)
Vietnam is a populous nation experiencing rapid social and economic transition. These changes, in combination with the spread of sexually transmitted infections such as HIV/AIDS, are compromising the reproductive health of young Vietnamese. Access to reliable reproductive health information is limited and social taboos prevent young people from talking openly about this topic. A huge number of young people living in Vietnam thus find themselves without access to relevant, accurate, non-threatening and unbiased information about sexuality and sexual health. The research outlined in this thesis approaches the issue of sexual health information provision for young people living in Vietnam from a participatory action research foundation. A key focus is investigation of the ways in which young people living in Vietnam can be included in the development of online sexual health communication tools by, for and about young Vietnamese. As part of this investigation, this thesis describes research conducted with young Vietnamese in Australia and Vietnam to identify and elucidate their reproductive health information needs, as situated within the contemporary Vietnamese socio-cultural context. The research was undertaken in order to determine how an online resource might meet these needs. This exploratory process involved the utilisation of a range of research methods to determine the website's optimal content, style, features and tone in relation to the Vietnamese context and requirements of its target users. It is hoped that the record of discovery resulting from this research journey will contribute to the existing body of knowledge on online health communication and participatory approaches to the development of context-sensitive health and behaviour-change communication.
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Let's talk (discreetly) about sex. The content generation and design of an online sexual and reproductive health information resource for young Vietnamese: a communications perspective.Clements, Alice Faith, alice.clements@rmit.edu.au January 2007 (has links)
Vietnam is a populous nation experiencing rapid social and economic transition. These changes, in combination with the spread of sexually transmitted infections such as HIV/AIDS, are compromising the reproductive health of young Vietnamese. Access to reliable reproductive health information is limited and social taboos prevent young people from talking openly about this topic. A huge number of young people living in Vietnam thus find themselves without access to relevant, accurate, non-threatening and unbiased information about sexuality and sexual health. The research outlined in this thesis approaches the issue of sexual health information provision for young people living in Vietnam from a participatory action research foundation. A key focus is investigation of the ways in which young people living in Vietnam can be included in the development of online sexual health communication tools by, for and about young Vietnamese. As part of this investigation, this thesis describes research conducted with young Vietnamese in Australia and Vietnam to identify and elucidate their reproductive health information needs, as situated within the contemporary Vietnamese socio-cultural context. The research was undertaken in order to determine how an online resource might meet these needs. This exploratory process involved the utilisation of a range of research methods to determine the website's optimal content, style, features and tone in relation to the Vietnamese context and requirements of its target users. It is hoped that the record of discovery resulting from this research journey will contribute to the existing body of knowledge on online health communication and participatory approaches to the development of context-sensitive health and behaviour-change communication.
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The effect of a provincial communcation strategy to address HIV, AIDS, STIs and TB (HAST) in the Limpopo ProvinceRapakwana, Ngwako Johannah 02 1900 (has links)
The lack of a contextualised, relevant communication strategy focusing specifically on
HAST diseases in the Limpopo Province was the impetus for this research. The
purpose of this study was, therefore, to explore the knowledge, perceptions and
utilisation of health facilities for HAST in order to develop an acceptable and effective
communication strategy for the Province to address the high rate of HAST diseases.
The study followed a qualitative approach guided by the major tenets of the Health
Belief Model, namely, to determine modifying factors, individual beliefs and cues for
action. An in-depth literature review was followed by focus group interviews with the
community members and personal interviews with District and Provincial Deputy
Directors. Based on these findings, a communication strategy was drafted and piloted
for three months in one of the districts in Limpopo. Further refinement of the
communication strategy followed after member-checking and further interviews with
directors HAST.
The final strategy specifically focused on risk groups with each of the diseases in terms
of their beliefs and perceptions. It further resulted in guidelines for health providers in terms of the content and implementation of effective communication strategies within
the context of educational, cultural, social and economic factors relevant to Limpopo / Health Studies / D. Litt. et Phil. (Health Studies)
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Exploring factors that influence condom use among high school teenagers aged between 16 and 18 years in Dutywa District, Eastern Cape, South AfricaMnyipika, Nomandla 06 1900 (has links)
Text in English / The Department of Education nationwide introduced HIV and AIDS care and support for learning and teaching programmes as intervention strategies for supporting vulnerable learners. Despite these interventions, teenagers continue to fall pregnant and this increases their vulnerability to HIV infection. HIV and STIs are rife among teenagers owing to ignorance and peer pressure, among other factors. The aim of this exploratory qualitative study was to explore factors that influence condom use among high school teenagers aged between 16 and 18 in Dutywa District. Focus group discussions and in-depth face-to-face interviews with 12 high school teenagers from one high school (High School X) were used to collect data. Thematic analysis was used to analyse data. The findings of this study revealed that high school teenagers are not using condoms to any significant degree. In their opinion, condoms limit sexual pleasure; they indicate a lack of trust and unfaithfulness between partners and are associated with sexually transmitted diseases. The findings of this study are significant for the policy implementation of schools. / Sociology / M.A. (Social Behaviour Studies in HIV and AIDS)
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