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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.
11

Parasites, ploidy, and sex: implications for gene expression and adaptive molecular evolution in Potamopyrgus antipodarum

Bankers, Laura 01 August 2017 (has links)
The trajectory of evolutionary adaptation can be influenced both by the interactions of organisms with their environments as well as by the biological characteristics of the organisms themselves. My dissertation research uses the New Zealand freshwater snail Potamopyrgus antipodarum to 1) gain important insight into how coevolutionary interactions between hosts and parasites influence patterns of gene expression and genetic differentiation of hosts and, 2) evaluate how reproductive mode, and ploidy level affect patterns of adaptive molecular evolution. Coevolutionary interactions between hosts and parasites are a primary source of strong natural selection that can lead to rapid evolutionary change. Here, I used evaluation of patterns of gene expression and genetic differentiation to take critical steps towards characterizing the genomic basis of coevolutionary interactions between P. antipodarum and Microphallus livelyi. I found that M. livelyi-infected P. antipodarum exhibit systematic downregulation of genes relative to uninfected P. antipodarum. The specific genes involved in response to parasites differ markedly across lakes, consistent with population-specific host-parasite interactions leading to population-specific evolutionary trajectories. I also identified a set of rapidly evolving loci that represent promising candidates for targets of parasite-mediated selection across lakes as well as within each lake population. These results constitute the first genomic evidence for population-specific responses to coevolving infection in the P. antipodarum-M. livelyi interaction and provide new insights into the genomic basis of coevolutionary interactions in nature. I also generated and characterized the first transcriptomic resources for Microphallus parasites collected from two species of Potamopyrgus snails (P. antipodarum and P. estuarinus). These data both revealed that these parasites appear to represent distinct genetic lineages, which is interesting in light of the tight coevolutionary interactions between P. antipodarum and M. livelyi, and lay the groundwork for future research. Polyploidy has the potential to facilitate adaptive evolution by providing redundant genome copies that are free to evolve new functions. By contrast, asexuality, with which polyploidy is often associated, is expected to restrict adaptive evolution by decreasing the efficacy of natural selection and access to new genetic variation. I evaluated whether and how ploidy level and reproductive mode influence patterns of adaptive molecular evolution in P. antipodarum to assess 1) the potential evolutionary genomic benefits of recent polyploidy, and 2) how patterns of adaptive molecular evolution in asexuals are influenced by polyploidy. I compared patterns of positive selection in 60 genes across 27 P. antipodarum lineages (10 diploid sexuals, 12 triploid asexuals, 5 tetraploid asexuals) and a diploid sexual outgroup, Potamopyrgus estuarinus. I found little evidence that ploidy level and/or reproductive mode influence patterns of positive selection in P. antipodarum. Even so, this study provides initial steps in evaluating whether ploidy level and reproductive mode influence patterns of adaptive molecular evolution. Taken together, my dissertation work contributes new insights to the field of host-parasite coevolutionary interactions and will inform future studies into how ploidy level and reproductive mode influence patterns of adaptive molecular evolution.
12

Diversity and evolution of reproductive systems in Mycocepurus fungus-growing ants

Rabeling, Christian 12 October 2012 (has links)
The general prevalence of sexual reproduction over asexual reproduction among metazoans testifies to the evolutionary, long-term benefits of genetic recombination. Despite the benefits of genetic recombination under sexual reproduction, asexual organisms sporadically occur throughout the tree of life, and a few asexual lineages persisted over significant evolutionary time without apparent recombination. The study of asexual organisms therefore may provide clues to answer why almost all eukaryotes reproduce via meiosis and syngamy and why asexual eukaryotes are almost always evolutionarily short-lived. Towards understanding the evolution of asexual lineages in the Hymenoptera, I first review the diversity of reproductive systems in the Hymenoptera, introduce the study organism, the fungus-gardening ant Mycocepurus smithii, and discuss my research objectives. Second, I integrate information from reproductive physiology, reproductive morphology, natural history and behavior, to document that that queens of M. smithii are capable of thelytokous parthenogenesis, workers are sterile, and males are absent from the surveyed population. These results suggest that M. smithii might be obligately asexual. To place the origin and maintenance of asexual reproduction in M. smithii in an evolutionary context, I use molecular phylogenetic and population-genetic methods to (i) test if M. smithii reproduces asexually throughout its distribution range; (ii) infer if asexuality evolved once or multiple times; (iii) date the origin of asexual reproduction in M. smithii; and (iv) elucidate the cytogenetic mechanism of thelytokous parthenogenesis. During field collecting for these studies throughout the Neotropics, I discovered a new species of obligate social parasite in the genus Mycocepurus. Social parasites are of great interest to evolutionary biology in order to elucidate mechanisms demonstrating how parasites gained reproductive isolation from their host species in sympatry. I describe this new parasite species, characterize its morphological and behavioral adaptations to the parasitic lifestyle, and discuss the parasite’s life history evolution in the context of social parasitism in fungus-growing ants. The dissertation research integrates population-genetic, phylogenetic, physiological and morphological approaches to advance our understanding of the evolution of reproductive systems and diversity of life-history traits in animals. / text
13

Neviditelná sexualita: Specifika života asexuálních lidí v rámci heteronormativní společnosti / Invisible sexuality: Specifics of the Life of Asexual People within Heteronormative Society

Andresová, Nela January 2019 (has links)
Thesis deals with social life of asexual people in the Czech Republic. The author focuses on the areas of acceptance of their own sexual identity as asexual, coming out and feelings of stigmatization, relationships and intimacy, belonging to LGBT+ community and the perception of the existence of a separate asexual community and the visibility of asexuality in society. For the purpose of the work was carried out qualitative research among asexual people, who selfidentify as asexual. The aim of the analysis was to determine how social life of asexuals differs within the heteronormative society. Thesis is based on differences between asexuals and heteronormative majority, especially in relationships and sexual behavior. The difference is also in other aspects of their life. People often don't know the meaning of asexuality, which can result in social stigmatization of asexuals due to pressure to accept a traditional model of relationship. In some respects, asexual people are similar to other sexual minorities, but not everyone feels to be part of LGBT+ community. Czech asexuals feel to be invisible in our society and they form networks among themselves through the internet forum asexual.cz. However, they don't create a separate community or social movement and they still remain socially invisible....
14

A sexual Series: Visningsex / Touching Upon the Aarti

Elg, Eva-Marie/Emie January 2023 (has links)
The art series A Sexual Series is based on posthumanist theory and asexual experience. Shapes of performative alter egos materialized from a queer cyborg position of technologically enhanced crip experiences (the strong symbolical constructing process of straightening scoliosis surgery). From the position of a glitch reflecting a postindividualist future, the AI sexbot is a metaphoric, elevated cyborg drag version of the artist to embody asexuality and queer Otherness. Based on multitudes of contradictions to encourage self-reflection, the series explores the complexities of ob/scene and on/scene performances; the position of a sex positive asexual as well as questions of belonging as a naturally artificial rebel. This essay touches upon rituals as well as performative methods of disidentification as a tool to reimagine shame, to ghost the own body and to stop being a pleaser.
15

\"Minha vida de ameba\": os scripts sexo-normativos e a construção social das assexualidades na internet e na escola / \"My life as an amoeba\": sexual normative scripts and the social construction of asexualities on the internet and in school

Oliveira, Elisabete Regina Baptista de 06 March 2015 (has links)
O objetivo desta pesquisa de doutorado é compreender as trajetórias de autoidentificação de indivíduos assexuais, com destaque para suas interações sociais na escola durante os anos da educação básica. Trata-se de uma pesquisa de caráter exploratório, de natureza qualitativa e de perspectiva sociológica, que se insere nos estudos de diversidade sexual no âmbito escolar, sob a ótica de gênero. A assexualidade é compreendida, neste trabalho, como forma de viver a sexualidade caracterizada pelo desinteresse pela prática sexual, que pode ou não ser acompanhado pelo desinteresse por relacionamentos amorosos. O desinteresse sexual/amoroso - construído social, histórica e culturalmente como transtorno psicológico ou fisiológico - tem sido ressignificado, a partir do início do século XXI, como forma distinta e legítima de sexualidade, situada no espectro mais amplo da diversidade sexual. A emergência de comunidades assexuais virtuais, com vários graus de mobilização em diferentes países inclusive no Brasil - tem dado visibilidade a esta categoria e contribuído para fomentar a discussão e os estudos sobre a assexualidade. Para esta pesquisa, foram entrevistadas 40 pessoas autoidentificadas como assexuais - sendo 8 entrevistas presenciais e 32 entrevistas por e-mail -, as quais foram contatadas pelo Blog Assexualidades, ferramenta virtual de pesquisa criada com o objetivo de facilitar a comunicação com comunidades e indivíduos assexuais brasileiros. A análise teve por base a bibliografia construcionista sobre a sexualidade, com destaque para a Teoria dos Scripts Sexuais dos sociólogos norte-americanos John Gagnon e William Simon, bem como a teoria de gênero de Joan Scott, entre outros/as estudiosos/as da sexualidade na perspectiva construcionista. Os resultados da investigação mostram de que modo os scripts sexo-normativos - diretrizes baseadas em normas sociais que estabelecem o interesse sexual/amoroso como universal e a atividade sexual como compulsória nas relações amorosas, presentes nas construções de sexualidade e gênero - permeiam as experiências de autoidentificação dos/as entrevistados/as, sobretudo, em suas interações na internet e com os pares na instituição escolar. Por um lado, as comunidades virtuais e redes sociais têm um peso significativo na afirmação da assexualidade na contemporaneidade, uma vez que o conceito de assexualidade nasceu e tem se propagado na internet, agregando pessoas do mundo todo em torno da identidade assexual. Por outro lado, a escola se revela local imprescindível para a imposição dos padrões de gênero e sexualidade que chancelam scripts hetero e sexo-normativos, porém, muito ausente em relação ao debate sobre as especificidades da assexualidade e pouco presente na mediação das tensões que podem garantir ou violar o reconhecimento da diversidade sexual em suas ações no âmbito da educação em sexualidade. / The purpose of this doctoral research is to understand self-identification trajectories of asexual individuals, giving emphasis to their school experiences and interactions during basic education. This is an exploratory qualitative sociological research, part of school sexual diversity studies, under the perspective of gender. In this research, asexuality is understood as a form of sexuality characterized by the disinterest in sexual activity, which may or may not be accompanied by the lack of interest in romantic relationships. Sexual/romantic disinterest - constructed socially, historically and culturally as a psychological or physiological disorder - has been reinterpreted as of the beginning of the 20th century, as a distinct and legitimate form of sexuality, situated within the broader spectrum of sexual diversity. The emergence of online asexual communities, with varying degrees of mobilization in different countries - including Brazil - has given visibility to this category and has contributed to discussion and research about asexuality. For this research, I interviewed 40 self-identified asexual people 8 face to face interviews and 32 e-mail interviews - who were contacted through Blog Assexualidades, an online research tool created to facilitate communication with Brazilian asexual individuals and communities. The analysis was based on the constructionist literature on sexuality, particularly John Gagnon and William Simons Sexual Script Theory, as well as Joan Scotts gender theory, among other constructionist theorists. Research results show how sexual normative scripts i.e. assumptions based on the universality of sexual/romantic interest and the naturalization of sexual activity in romantic relationships as part of social construction of sexuality and gender - permeate respondents self-identification experiences, particularly in their internet interactions and their peer relations during the school years. On one hand, online communities and social networks play a significant role in the affirmation of asexuality in contemporaneity, taking into consideration the fact that asexuality was created and has expanded on the internet, gathering people from all over the world around an asexual identity. On the other hand, research findings show that the school environment has been essential for the imposition of gender and sexuality standards that legitimate sexual and heteronormative scripts. However, the school institution has been neglectful about the discussion of the specificities of asexuality and has been doing very little to mediate the tensions that can either guarantee or violate the recognition of sexual diversity in sexuality education initiatives.
16

\"Minha vida de ameba\": os scripts sexo-normativos e a construção social das assexualidades na internet e na escola / \"My life as an amoeba\": sexual normative scripts and the social construction of asexualities on the internet and in school

Elisabete Regina Baptista de Oliveira 06 March 2015 (has links)
O objetivo desta pesquisa de doutorado é compreender as trajetórias de autoidentificação de indivíduos assexuais, com destaque para suas interações sociais na escola durante os anos da educação básica. Trata-se de uma pesquisa de caráter exploratório, de natureza qualitativa e de perspectiva sociológica, que se insere nos estudos de diversidade sexual no âmbito escolar, sob a ótica de gênero. A assexualidade é compreendida, neste trabalho, como forma de viver a sexualidade caracterizada pelo desinteresse pela prática sexual, que pode ou não ser acompanhado pelo desinteresse por relacionamentos amorosos. O desinteresse sexual/amoroso - construído social, histórica e culturalmente como transtorno psicológico ou fisiológico - tem sido ressignificado, a partir do início do século XXI, como forma distinta e legítima de sexualidade, situada no espectro mais amplo da diversidade sexual. A emergência de comunidades assexuais virtuais, com vários graus de mobilização em diferentes países inclusive no Brasil - tem dado visibilidade a esta categoria e contribuído para fomentar a discussão e os estudos sobre a assexualidade. Para esta pesquisa, foram entrevistadas 40 pessoas autoidentificadas como assexuais - sendo 8 entrevistas presenciais e 32 entrevistas por e-mail -, as quais foram contatadas pelo Blog Assexualidades, ferramenta virtual de pesquisa criada com o objetivo de facilitar a comunicação com comunidades e indivíduos assexuais brasileiros. A análise teve por base a bibliografia construcionista sobre a sexualidade, com destaque para a Teoria dos Scripts Sexuais dos sociólogos norte-americanos John Gagnon e William Simon, bem como a teoria de gênero de Joan Scott, entre outros/as estudiosos/as da sexualidade na perspectiva construcionista. Os resultados da investigação mostram de que modo os scripts sexo-normativos - diretrizes baseadas em normas sociais que estabelecem o interesse sexual/amoroso como universal e a atividade sexual como compulsória nas relações amorosas, presentes nas construções de sexualidade e gênero - permeiam as experiências de autoidentificação dos/as entrevistados/as, sobretudo, em suas interações na internet e com os pares na instituição escolar. Por um lado, as comunidades virtuais e redes sociais têm um peso significativo na afirmação da assexualidade na contemporaneidade, uma vez que o conceito de assexualidade nasceu e tem se propagado na internet, agregando pessoas do mundo todo em torno da identidade assexual. Por outro lado, a escola se revela local imprescindível para a imposição dos padrões de gênero e sexualidade que chancelam scripts hetero e sexo-normativos, porém, muito ausente em relação ao debate sobre as especificidades da assexualidade e pouco presente na mediação das tensões que podem garantir ou violar o reconhecimento da diversidade sexual em suas ações no âmbito da educação em sexualidade. / The purpose of this doctoral research is to understand self-identification trajectories of asexual individuals, giving emphasis to their school experiences and interactions during basic education. This is an exploratory qualitative sociological research, part of school sexual diversity studies, under the perspective of gender. In this research, asexuality is understood as a form of sexuality characterized by the disinterest in sexual activity, which may or may not be accompanied by the lack of interest in romantic relationships. Sexual/romantic disinterest - constructed socially, historically and culturally as a psychological or physiological disorder - has been reinterpreted as of the beginning of the 20th century, as a distinct and legitimate form of sexuality, situated within the broader spectrum of sexual diversity. The emergence of online asexual communities, with varying degrees of mobilization in different countries - including Brazil - has given visibility to this category and has contributed to discussion and research about asexuality. For this research, I interviewed 40 self-identified asexual people 8 face to face interviews and 32 e-mail interviews - who were contacted through Blog Assexualidades, an online research tool created to facilitate communication with Brazilian asexual individuals and communities. The analysis was based on the constructionist literature on sexuality, particularly John Gagnon and William Simons Sexual Script Theory, as well as Joan Scotts gender theory, among other constructionist theorists. Research results show how sexual normative scripts i.e. assumptions based on the universality of sexual/romantic interest and the naturalization of sexual activity in romantic relationships as part of social construction of sexuality and gender - permeate respondents self-identification experiences, particularly in their internet interactions and their peer relations during the school years. On one hand, online communities and social networks play a significant role in the affirmation of asexuality in contemporaneity, taking into consideration the fact that asexuality was created and has expanded on the internet, gathering people from all over the world around an asexual identity. On the other hand, research findings show that the school environment has been essential for the imposition of gender and sexuality standards that legitimate sexual and heteronormative scripts. However, the school institution has been neglectful about the discussion of the specificities of asexuality and has been doing very little to mediate the tensions that can either guarantee or violate the recognition of sexual diversity in sexuality education initiatives.
17

Asexualita - identifikace a sexualita / Asexuality - identification and sexuality

Krejčová, Alžběta January 2018 (has links)
The purpose of this thesis and its research is to cover the asexual community in terms of identification and characteristics of sexual life. In theoretical part the groups Gray-A, demisexual and aromantic are described. It compares the approaches of asexuality as a disorder and as a sexual orientation. It discusses asexuality and relationships, celibacy or physical contact. The research gathered data about group prevalence, self-identification, sexual preferencies - real as well as ideal, masturbation and pornography. The research sample accounted for 160 respondets from the AVEN forum. The online questionnaire was prepared especially for this thesis. The data are presented as whole as well as divided into two age groups - the younger (18-23) and older (24-59) group. The significant difference was found in these areas: usage of sex toys/objects of sexual pleasure, number of sexual partners, relationship status and the age of first sexual intercourse. Theoretical part - in concordancy with research - shows, that a portion of asexuals: has relationships, uses pornography and sexual toys, is romantic and experiences various types of sex.
18

“This is who I am” : Representation av asexualitet i samtida coming of age-litteratur

Lilja, Malin January 2021 (has links)
Syftet med studien är att utforska representationer av asexualitet i samtida coming of age-ungdomsromaner med fokus på hur asexualitet (o)möjliggörs som en oproblematiserad position. Detta görs genom en närläsning av romanerna Tash Hearts Tolstoy, Let’s Talk About Love, Loveless och Beyond the Black Door utifrån ett queerteoretiskt perspektiv. Romanernas skildringar av asexualitet utmanar föreställningar om att sexuellt begär är en essentiell del i vuxenblivandet och tillåter den asexuella positionen att existera utan att formas av negativa stereotyper. Romanernas huvudpersoner genomgår processer av att komma till insikt om sin asexuella identitet, acceptera den för sig själva och komma ut med den för omgivningen. Den obligatoriska sexualiteten är ständigt närvarande i dessa processer men det är den asexuella positionens marginaliserade position jämte den obligatoriska sexualiteten som framställs som problemet snarare än asexualiteten i sig. / The aim of the study is to explore representations of asexuality in contemporary coming of age young adult novels with a focus on how asexuality is made (im)possible as an unproblematic position. This is done through a close reading of the novels Tash Hearts Tolstoy, Let’s Talk About Love, Loveless and Beyond the Black Door from a queer theoretical perspective. The novels’ depictions of asexuality challenge notions that sexual desire is an essential part of becoming an adult and allow the asexual position to exist without being shaped by negative stereotypes. The protagonists of the novels go through processes of realizing and accepting their asexuality for themselves and also coming out to their surroundings. Compulsory sexuality is constantly present in these processes, but it is the marginalization of the asexual position in relation to compulsory sexuality that is understood as the problem rather than asexuality itself. / <p>2021-06-02</p>
19

Konstruktioner av queer : Interdiskursivitet och pendlande positioneringar i samtal om kön, sexualitet och relationer / Constructions of queer : Inter-discursivity and oscillating positionings in discussions about gender, sexuality and relationsships

Hagren Idevall, Karin January 2011 (has links)
Denna studie utgår från tre fokusgruppsamtal med sammanlagt tio personer som betraktar sig själva som queera. Syftet har varit att analysera positioneringar i relation till diskurser som konstituerar kön, sexualitet och relationer, och hur dessa positioneringar och diskurser konstrueras språkligt. Feminist Post-structuralist Discourse Analysis har använts som teori och metod, kompletterad med en analys utifrån systemisk-funktionell grammatik. Analysen har visat hur deltagarna genomgående konstruerar ett ifrågasättande av normer som organiserar och kategoriserar kön, sexualitet och relationer. Utifrån queer positionering har kön och sexualitet genom agentiva verbprocesser konstruerats som dynamiska och mångfaldiga. Även anti-hierarkiska och feministiska diskurser, tillsammans med en ovilja att definiera sexuell läggning och relationer, genomsyrar samtalen. Vidare har det framgått att queer konstrueras som perspektiv, men även som en praktikgemenskap med gränser för vad och vem som är queer. En analys av diskursers samspel med varandra har synliggjort ämnen som på olika sätt utmanar queers gränser, bland annat könsseparatism, pronomenet hen, pornografi och asexualitet. Analysen har dessutom visat att det queera subjektet rör sig mellan olika positioneringar beroende på kontexten, och att positioneringar kan vara såväl intentionella som påtvingade. Den queera pendlar därmed mellan makt och maktlöshet beroende på relationen till andra individer och diskurser. / This thesis is based on three focus group discussions including a total of ten individuals who consider them selves as being queer. The research aim has been to analyze subject positionings in relation to discourses that constitute gender, sexuality and relationships, and how these positionings and discourses are linguistically produced. Feminist Post-structuralist Discourse Analysis, complemented by a systemic-functional grammar analysis, has been the theoretical and methodological approach. The result has shown how the participants consistently position them selves against norms that organizes and categorizes gender, sexuality and relationships. The participants have from queer positionings as agents in verb processes articulated sexuality and gender as dynamic and multiplex. They have also drawn on anti-hierarchical and feminist discourses, as well as articulated a resistance to define sexual orientation and relationships. Queer has been produced as a perspective, but also as a community of practice with it's own norms for what and who can be considered as queer. An analysis of interaction among discourses has exposed issues that challenge the borders of queer, for example gender separatism, gender neutral pronouns, pornography and asexuality. The analysis has furthermore shown that the queer subject move amongst different positionings depending on the context, and that positionings can be intentional as well as imposed. The queer individual is therefore oscillating between power and powerlessness depending on the relationship to other individuals and discourses.
20

“Jag vill ha mer än bara en försmak…” : En kvalitativ studie om sexuella rättigheter och fysisk funktionsnedsättning / ” I want more than just a taste” : A qualitative study about sexual rights and physical disability

Larsson, Amanda January 2021 (has links)
Being viewed as a sexual being is perhaps not something often considered by most able-bodied people. Yet, lacking that kind of consideration is not a luxury that people with physical impairments naturally get. The purpose of this study is to, by using the perspective of crip theory and the social model, examine how the societal view of physical impairment and sexuality affect people with physical impairments and their ability to express and act on their sexuality. Five interviews were transcribed from two podcasts wherein four interviewees, two cisgendered men and two cisgendered women, talk about their personal experiences with navigating a socially, and sometimes physically, inaccessible sexual marketplace. Results show that all four interviewees agree that a societal view of people with physical impairments as unattractive and asexual has affected their self-esteem and self-image by having internalized the societal ableist attitudes of what it means to have an attractive body and to be an attractive partner. Results also show how the female interviewees have experienced an increased need for affirmations of their physical attractiveness through sexual and romantic relationships and how they believe these needs to be grounded in their internalized ableism.  Furthermore, the results of this study reveal how the male interviewees believe their acts of having bought sexual services from sexual surrogates to be grounded in the sexual exclusion they experience from the sexual market because of their physical impairments.

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