• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 948
  • 702
  • 153
  • 122
  • 87
  • 66
  • 19
  • 19
  • 13
  • 10
  • 9
  • 9
  • 7
  • 5
  • 5
  • Tagged with
  • 2587
  • 705
  • 378
  • 274
  • 258
  • 193
  • 190
  • 188
  • 185
  • 183
  • 183
  • 162
  • 161
  • 160
  • 158
  • 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.
361

PRRSV-webtool: a web-based database and phylogenetic tool to study molecular epidemiology and evolution ofporcine reproductive and respiratory syndrome virus, and related tooland algorithm

Wong, Lai-yin, Charles., 王禮賢. January 2013 (has links)
Porcine Reproductive and Respiratory Syndrome virus (PRRSV) causes the disease - Porcine Reproductive and Respiratory Syndrome (PRRS) which is one of the most economically important diseases for pig farmers. Since it was discovered in the United States and Europe, it has quickly affected the swine industry all over the world. Studying and controlling PRRSV has become an important issue in swine industry and scientific community, and has raised the concerns of governments like US and China. By using different bioinformatics and phylogenetics tools, scientists could understand the epidemiology and evolution of PRRSV from genomic data. However, a well-designed database for PRRSV sequence and relevant meta-information are generally required for the tools to produce insightful results. Therefore, I would like to introduce an easily accessible web platform for PRRSV analysis - PRRSV-Webtool. The core component of PRRSV-Webtool is phylogenetic reconstruction. Instead of using traditional phylogenetic reconstruction, a new method of reconstruction was introduced - Reconstruction by Addition of Taxon (RAT). RAT could build a phylogenetic tree from known existing phylogeny. Simulation tests were performed to evaluate the accuracies of RAT using PRRSV dataset. The percentages of correct branch reconstruction are 73.81% for type 1 PRRSV dataset and 80.68% for type 2 PRRSV dataset. Another important function of PRRSV-Webtool is genotyping. RAT could correctly identify the genotype of all sequences in the testing datasets. PRRSV-Webtool combined three main components: database, phylogenetic tool and World Wide Web. By using PRRSV-Webtool, the users can study their own PRRSV genome data easily via the web browser. Tools in PRRSV-Webtool can allow users to know more about their PRRSV isolates related to other field samples. With our PRRSV-Webtool, scientists and veterinaries can help to improve their understanding of PRRSV and help to control the virus by accelerating the process of virus surveillance and field sampling. / published_or_final_version / Biological Sciences / Master / Master of Philosophy
362

Life-history variation and evolved response to food stress in Oncopeltus fasciatus (Hemiptera: Lygaeidae)

Attisano, Alfredo January 2012 (has links)
Every organism needs to survive and successfully reproduce in the face of changing environmental conditions in which variation in resource availability can seriously limit performance. Organisms can respond to the variation in quality or availability of food resources with behavioural and physiological accommodations going from the baseline physiological response to environmental stressors to complex life-history strategies like migration and diapause. In insects, one avenue to cope with the resources’ variation is to plastically tune the reproductive system to the environmental conditions in order to shift resources away from reproduction during unfavourable periods but maximize it when resources are abundant. I studied the role of reproductive physiology in both males and females in mediating a response to challenging conditions determined by a lack of food resources or the presence of qualitatively different diets using the milkweed bug, Oncopeltus fasciatus, as model species. I studied the role of oosorption, a plastic physiological response through which resources can be recovered and redirected to body maintenance and survival, in shaping behavioural strategies to cope with challenging environments. I also studied the effects of diet quality on male’s sexual behaviour and how these modulate the trade-offs between reproduction and survival. I then investigated how the effects of diet quality, sexual maturation and rearing conditions influence the occurrence of reproductive diapause in both males and females. I found that females exposed to different diets plastically adapt their schedule of reproduction depending on diet quality: this also influences the occurrence of oosorption in the ovary mediating the amount of resources that are directed to reproduction or survival. Diet quality influences males’ sexual behaviour so that even after a long-term adaptation on an alternative artificial diet, they invest more in reproduction at the expenses of survival when fed on an ancestral high quality diet; this is achieved with a shift in the trade-off between reproduction and survival. The occurrence of reproductive diapause in both males and females is a function of several factors: the quality of food resources ultimately modulates sexual maturation in adult individuals determining the occurrence of diapause or reproduction. Finally, oosorption may be involved in the evolution of alternative condition-dependent strategies as an adaptive physiological mechanism to cope with stressful environments; thus females from different populations may be able either to migrate in favourable areas where they can exploit abundant food resources or remain residents and perform high levels of oosorption to cope with the seasonal shortage of food.
363

Reproduction has never been natural: the social construction of reproduction in the age of new reproductivetechnologies

Tang, Shiu-wai., 鄧紹偉. January 2000 (has links)
published_or_final_version / Sociology / Master / Master of Philosophy
364

The Rhetorics of U.S. Abortion Narratives: Thematic Continuities, Shifting Applications and Political Strategies, 1969-Present

Thomsen, Carly Ann January 2008 (has links)
This thesis seeks to understand the various forces that have shaped the form, content, utilization and emergence of abortion narratives--both within a historical context and for political value. By comparing the themes that emerge within and across three sets of narratives--anti-abortion narratives, pre-Roe narratives that support abortion rights, and post-Roe abortion-rights narratives--and by identifying both gaps and influxes in the use of narratives, this thesis argues that the content and utilization of abortion narratives is directly connected to broader discursive strategies and political ideologies of reproductive rights organizations.
365

A Quantified Approach to Tomato Plant Growth Status for Greenhouse Production in a Semi Arid Climate

Renda da Costa, Paula MR January 2007 (has links)
Balancing plant growth between vegetative and reproductive status is crucial for producing high quality greenhouse tomatoes while maintaining high productivity in long crop production seasons. In the tomato industry, certain plant morphological characteristics are used to classify plant growth status as vegetative, reproductive or balanced. Each growth status has been associated with distinct greenhouse environments which reduce or enhance transpiration.The effect of different transpiration on vegetative, reproductive or balanced plant growth status as defined by a set of plant morphological characteristics was investigated. To validate the practical significance of such classification, growth status was quantified as the relationship between variations in morphological characteristics and the fresh weight distributed between reproductive and vegetative organs.Two electrical conductivity (EC) levels of the nutrient solution, high and standard EC, were combined with two potential transpiration environments, low and high potential transpiration. All treatment combinations were contrasted with a reference greenhouse environment similar to the industry standard.Electrical conductivity had the greatest effect on morphological characteristics which were reduced in size with high EC. For each EC level, the response decreased for increasing potential transpiration. Stem diameter had the greatest sensitivity to the different treatment combinations. For the standard EC and for the range of potential transpirations achieved, stem diameter varied within a relatively narrow range, close to the industry standard 'threshold' used to classify a balanced tomato plant. A reproductive plant growth status, as evaluated by a smaller value than this threshold, was observed only with high EC. No vegetative plants were produced within any potential transpiration or EC treatment combination.High EC decreased the cumulative total fresh weight production by the same magnitude for all potential transpirations. Potential transpiration had a minimal effect on the total fresh weight production or on its components. As a result, the fresh weight ratio between reproductive and vegetative plant organs was similar for most potential transpiration environments, regardless of variations in stem diameter. Therefore, within the range of potential transpiration environments achieved, the distinction between vegetative and reproductive growth status as an indicator of fresh weight distribution and fruit yields could not be quantitatively validated.
366

Doe v. Canada: Lesbian Women, Assisted Conception, and a Relational Approach to Rights

Dughman, Sandra 14 January 2010 (has links)
This thesis examines Doe v. Canada, a case brought before the Ontario Court of Appeals with the purpose to declare that the definition of “assisted conception” set forth by the respective regulations discriminated against lesbian women. The regulatory framework of assisted conception is embedded with heteronormativity, heterosexism and an over medicalization of reproduction. The traditional liberal conception of rights, embedded in the Court’s decision did not allowed lesbian women to have access to assisted conception free from barriers that other women, seeking insemination with semen donated by their spouse or sexual partner, do not have to endure. However, If we shift our perspective of rights from a liberal view to a relational approach, we will be able consider such decisions from a perspective that takes into account not only the physical health implications of the use of this technology, but also all other social, psychological and contextual relevant factors.
367

Doe v. Canada: Lesbian Women, Assisted Conception, and a Relational Approach to Rights

Dughman, Sandra 14 January 2010 (has links)
This thesis examines Doe v. Canada, a case brought before the Ontario Court of Appeals with the purpose to declare that the definition of “assisted conception” set forth by the respective regulations discriminated against lesbian women. The regulatory framework of assisted conception is embedded with heteronormativity, heterosexism and an over medicalization of reproduction. The traditional liberal conception of rights, embedded in the Court’s decision did not allowed lesbian women to have access to assisted conception free from barriers that other women, seeking insemination with semen donated by their spouse or sexual partner, do not have to endure. However, If we shift our perspective of rights from a liberal view to a relational approach, we will be able consider such decisions from a perspective that takes into account not only the physical health implications of the use of this technology, but also all other social, psychological and contextual relevant factors.
368

Ethical and Sociocultural Considerations for use of Assisted Reproductive Technologies Among the Baganda OF Uganda

Mukasa, Martha N. 15 July 2013 (has links)
Anthropological research on the sociocultural outcomes from applications of Assisted Reproductive Technologies (ARTs) for infertility, particularly in sub-Saharan Africa, is greatly lacking and much needed. Narratives from individuals, couples, families, community leaders and members are particularly germane to medical anthropological studies on the intersection of science and technology in the new millennium. With ART applications still in their infancy in sub-Saharan Africa, research of this nature may be of benefit in determining how best to apply ARTs within important cultural frameworks and allow infertile couples and other recipients the opportunity to minimize adverse results. This paper draws upon theoretical perspectives from anthropology, science and technology studies, ethnographic data from my field study in Uganda, and reviews of literature, to construct theories about how for the Baganda, the proliferation of ARTs could potentially change or disrupt cultural notions of power and identity and unseat core notions of kinship.
369

GRAM genes and abscisic acid (ABA) metabolism in the reproductive development of Arabidopsis thaliana

Baron, Kevin 06 1900 (has links)
Abscisic acid (ABA) is a key plant hormone regulating agronomically important processes including seed maturation and dormancy, stomatal opening and closure, along with the transcriptional and physiological response of plants to abiotic and biotic stresses. The current study sought to functionally characterize members of an ABA-responsive gene family encoding GRAM (Glucosyltransferases, Rab-like GTPase activators and Myotubularins) domain proteins in Arabidopsis thaliana. Utilizing reverse genetics loss- and gain-of-function lines associated with GEM-RELATED 5 (GER5) were obtained, which displayed several defects in reproductive development. Gene expression profiling, RNA in situ hybridization and immunohistochemical techniques were utilized to evaluate GER5 and two closely related GRAM genes, GEM-RELATED 1 (GER1) and GLABRA2 EXPRESSION MODULATOR (GEM) in reproductive structures. Microarray profiling of seeds from ger5-2 mutants and wild-type plants revealed transcriptional changes in carbohydrate metabolism, hormone signaling and catabolic processes accompanied seed development defects of ger5-2 mutants. Seed germination assays further revealed ger5-2 mutants exhibited reduced sensitivity to ABA. In assessing GER5, GER1 and GEM as putative ABA-response genes, a second study evaluated the expression of GRAM, AuTophaGy-related (ATG), and ABA-response genes in source and sink organs exposed to abiotic stress or within mutant backgrounds deficient in sugar signaling. Monodansylcadaverine (MDC) staining was also utilized to localize autophagosomes or autophagic bodies within vegetative or reproductive organs during plant development, or in response to carbon starvation or abiotic stress. In a third study transcriptional differences in ABA metabolism, transport and homeostasis were examined within reproductive organs (cauline leaves, inflorescence meristem, developing siliques) exposed to cold and heat stress. This study revealed reproductive organs are characterized by unique patterns of ABA metabolism which differ from tissues typically associated with classical ABA responses. Together, these studies indicate GER5, an uncharacterized ABA-responsive GRAM domain gene, plays a novel role in the reproductive development of plants and that ABA metabolism and signaling are uniquely regulated in reproductive organs.
370

“What does this do?” The Neoliberal Creep, Sexual Health Work and the Deregulation of Emergency Contraception

Fryer, Sara Anne 27 March 2014 (has links)
Beginning with eight women’s experiences in accessing emergency contraception from a pharmacist, this research brings into view the undocumented “sexual health work” of obtaining the drug in northern Ontario. Between 2005 and 2008, emergency contraception was deregulated to behind-the-counter, forcing women to submit to mandatory counselling and screening about sex, menstruation and contraception at the pharmacy. Situating unwanted pregnancy as harmful in this context, an institutional ethnographic analysis explores the activities of health service delivery and identifies the different ideological practices that shaped women’s access like the steady creep of neoliberalism, professional specialization and clinical power. Ideological discourses construct an ideal contraceptive user, who is patient, compliant and appears “responsible”, contributing to the stigmatization of women. Findings suggest that an inaccurate government definition of emergency contraception contributes to ignorance and misperceptions about function; this, along with an empty federal policy vacuum for women’s health contributes to its problematic status in women’s contraceptive options.

Page generated in 0.0599 seconds