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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.
161

Diets, estrogen environment of the fetus, and development of the reproductive tract and other systems

Ruhlen, Rachel L., January 2003 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 2003. / Typescript. Vita. Includes bibliographical references (leaves 99-111). Also available on the Internet.
162

An ethical analysis of the use of fertility drugs

Williams, Thomas D. January 2000 (has links)
Thesis (M.A.)--Trinity International University, 2000. / Abstract. Includes bibliographical references (leaves 67-72).
163

Diets, estrogen environment of the fetus, and development of the reproductive tract and other systems /

Ruhlen, Rachel L., January 2003 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 2003. / Typescript. Vita. Includes bibliographical references (leaves 99-111). Also available on the Internet.
164

A phenomenological study into infertility and the assisted reproductive technologies : U.S.A and Jamaica compared.

January 2007 (has links)
A Phenomenological Study into Infertility and the Assisted Technologies: USA and Jamaica Compared Infertility affects approximately 10-15% of all couples. This study explores the livedexperience of infertility and assisted reproductive technologies in Jamaica and the United States based on a phenomenological qualitative analysis of in-depth interviews conducted with 15 couples experiencing infertility in Jamaica and 15 couples in the United States. As with many small scale studies that explore issues of an extremely sensitive nature, the participants were recruited from the community through a combination of convenience and snowball sampling. The biopsychosocial model and postmodernism constituted the conceptual frameworks that guided this study. The factors contributing to infertility; the biopsychosocial consequences of infertility and medical treatment of infertility are described. Fertility, infertility and the assisted reproductive technologies (ARTs) are examined from ethical, legal, religious, and feminist perspectives. Empirical research derived from in-depth personal narratives of participants are used to explore the ways infertility impacts life's goals, self-esteem, faith, marriage, social relationships, and religious and cultural experiences. The results of the study yielded a list of thirteen themes that show the similarities and differences between Jamaica and the United States in relation to the topic under investigation. The study concludes with recommendations for public policies to address infertility as a public health concern and for social work with individuals, couples and extended families affected by the experience of infertility. / Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2007.
165

EFFECTS OF MANAGEMENT ON REPRODUCTIVE EFFICIENCY IN THOROUGHBREDS

Nagy, Reka 01 January 2006 (has links)
Many factors influence the reproductive efficiency of thoroughbred mares. This thesisestimated two separate models for 13 farms in the 2004 breeding season. One model isestimated for pregnancy outcomes, the other is estimated for breeding intervals.Statistically significant variables include age of the mare, number of breedings, certainmedications, farm size, last date of breeding for the first model. Statistically significantvariables for the second model include age, status of mare, number of breedings, certainmedication, and farm size. The model has implication to achieve an optimal breedingschedule and associated management decisions
166

The economics of the reproduction 'crisis' in transition Europe : the effect of shifts in values, income and uncertainty (with special reference to Russia)

Vandycke, Nancy January 1999 (has links)
This thesis investigates the causes for the abrupt, universal and virtually unprecedented decline in the total fertility rate in transition Europe. Using evidence from Russia, it tests two competing hypotheses on the fertility decline: the demographic and economic hypotheses. Empirical findings can be summarized as follows: I find insufficient support for the demographic hypothesis-the fertility decline in Russia cannot satisfactorily be explained by a simultaneous shift in values and attitudes towards reproduction and timing of births. In contrast, I provide preliminary cross-regional evidence to support the economic hypothesis-regions with the largest fall in (the proxy for) income and large uncertainty experienced the largest declines in the fertility rates. This result is consistent with Becker's economic model of reproductive behaviour, insofar as it establishes a positive relationship between changes in income and fertility. It however introduces an additional explanatory variable: people's perception of uncertainty. In a preliminary attempt to reconcile the standard economic model with these findings, a simple model of households' reproductive decision is developed. It shows that each household tends to postpone the decision for an incremental child, whenever there is widespread uncertainty. It suggests that, if the individual decision to procrastinate is replicated over a large number of households, it can lead to an aggregate, short-term fall in the fertility rate. Provided that conclusions for the transition European region can be drawn from the Russian evidence, this inquiry shows that fertility has declined in response to a lower income and higher uncertainty: it reflects the deterioration in the quality of life and a loss in welfare. Thus, it is a strong negative indicator of the transition process.
167

Prenatal Testing and Reproductive Freedom : A Mother´s Right to Choose

Karlsson, Lise-Lott January 2014 (has links)
The aim of this thesis is to analyse and examine the debate on prenatal testing in Western countries, with a special focus on my own country, Sweden. In the near future it might be possible for a pregnant woman to profile the DNA of her foetus with a simple blood test early in pregnancy. This method of prenatal testing – Non Invasive Prenatal Diagnosis (NIPD) – could potentially detect the genetic causes of almost every disease. I will argue that prenatal testing should be offered by society to all pregnant women, not only to those at highest risk of giving birth to children with severe conditions. I will do that from a perspective of reproductive freedom. Furthermore, I will argue that offering prenatal testing for some conditions (such as Downs’s syndrome) and not for others, is conflicting with the autonomous choice of the pregnant woman.
168

The ecology and evolution of wind pollination

Friedman, Jannice 08 December 2009 (has links)
The evolution of wind pollination (anemophily) has occurred at least 65 times in the flowering plants and over 10% of angiosperm species are wind pollinated. However the pollination and mating of anemophily species is poorly understood, particularly in comparison with animal-pollinated species. My thesis employs a range of approaches and tools to examine the evolution and ecology of wind pollination. These include comparative analyses, theoretical modeling, field and glasshouse experiments, the use of genetic markers and quantitative genetics. Experimental studies on diverse taxa were used to address questions concerned with the efficacy of outcrossing mechanisms, the ecological and demographic context of pollination and mating, and the plasticity of sex allocation. Comparative analyses indicated that wind pollination is correlated with unisexual flowers, reduced ovule number, small unshowy flowers, an absence of nectar, and open habitats. These analyses also demonstrated that anemophily originates more often in lineages with unisexual flowers. This suggests that wind pollination evolves in diclinous taxa as a mechanism of reproductive assurance because autonomous selfing is mechanically precluded. Empirical data on stigmatic pollen loads in 19 anemophilous species challenge the widespread assumption that anemophilous plants commonly have uniovulate flowers because they capture few pollen grains. Further, a model based on floral costs and the aerodynamics of pollen capture demonstrated that when flowers are inexpensive it is optimal to produce many flowers each with few ovules, because this allows more efficient sampling of the airstream. Manipulative field experiments on seven Carex species indicated that neither monoecy nor protogyny, two putative outcrossing mechanisms, are effective at limiting selfing. Based on these results I suggest that geitonogamy can provide reproductive assurance in anemophilous species with unisexual flowers. Field experiments and the application of sex-specific markers in Rumex nivalis revealed that the local neighbourhood of maternal plants affects pollination intensity and progeny sex ratios. Finally, I demonstrated that plant density in Ambrosia artemisiifolia affects stigmatic pollen loads but not outcrossing rates. Through a quantitative genetics experiment in A. artemisiifolia, I detected significant genetic variation for plasticity in sex allocation, potentially enabling adaptive adjustment of sex allocation to local environmental conditions.
169

Association of Intersex in Wild Fish with Wastewater Effluent in the Grand River, Ontario

Tanna, Rajiv Neal January 2012 (has links)
The Grand River watershed is the largest watershed in southern Ontario, and is expected to see major development and urban densification over the next 20 years. An expected 57% increase in population over the next two decades in urban centers such as Kitchener – Waterloo, Cambridge, Guelph and Brantford means an added load on the existing 30 wastewater treatment facilities serving the watershed. A subsequent increase in the amount of average flow and effluent released into the Grand River via the Waterloo and Kitchener wastewater treatment plants is also expected. The Waterloo and Kitchener wastewater plants are both secondary treatment plants, although neither plant currently nitrifies the wastewater prior to release. As a result, increased concentrations of ammonia and nitrate are found downstream of the treatment plant outfalls. Compounds introduced into the Grand River via the discharge of wastewater effluent can have impacts on resident biota such as fish. Disruption of the normal function of endocrine systems in fish has been associated with municipal effluents as well as chemicals that have been detected in these effluents. One of the major responses has been the presence of intersex (oocytes in testes) in fish downstream of the wastewater plant outfalls at sites around the globe. The research in this thesis examined resident fish for the variability and extent of intersex condition by adapting a new fragmented testis technique. Biomarkers of response such as relative gonad weight (GSI), relative liver weight (LSI) and condition (K) were also measured. The study focused on the Rainbow Darter (Etheostoma caeruleum) a dominant benthivorous fish species in the riffle habitats in the Grand River. An increased proportion of male Rainbow Darters sampled immediately downstream of the Waterloo outfall had a gonad lobe containing at least one testis-oocyte. The number of Rainbow Darter with more severe intersex (10-99 oocytes/lobe) also increased immediately downstream of the Waterloo outfall. A much more dramatic expression of intersex proportion and severity (>100 oocytes per testis lobe) was observed further downstream, below the Kitchener outfall. These patterns in intersex presence and severity were also observed in two other species collected at a subset of the original sites. Although there were minimal changes in GSI, LSI and K below the Waterloo outfall, differences were observed downstream of the Kitchener wastewater effluent outfall. Female Rainbow Darter downstream of the Kitchener outfall showed significant decreases in GSI and LSI, and increases in K. Male Rainbow Darter GSI and LSI data across sites did not express changes that coincided with MWWE outfalls, although small increases in condition were observed. These patterns of intersex and organism level responses suggest that the assimilation of wastewater effluent into natural receiving environments may have impacts on endocrine function and energy use and allocation in wild fish.
170

The Response of Wild Fish to Municipal Wastewater Effluent Exposures at Sites in Canada

Tetreault, Gerald 08 March 2012 (has links)
Aquatic receiving environments have long been used to dilute municipal wastewater effluents (MWWE) which are the largest discharge by volume into the aquatic environment in Canada. These treated effluents are a complex mixture of environmental contaminants that includes natural and synthetic hormones, pharmaceuticals, industrial chemicals, nutrients and ammonia. Discharge of MWWE may lead to serious problems in aquatic environments such as eutrophication, hypoxia as well as increased occurrence of disease and toxicity in resident aquatic biota. Reproductive impairment in fish has also been widely reported in association with exposure to wastewaters. Recently, concerns have been raised about the potential for municipal effluents to cause endocrine disruption in fish and other organisms. The effects of MWWE on fish and fish populations in Canada are currently poorly understood. The overall objective of this thesis is to contrast the impact of MWWE discharged into two Canadian rivers on sentinel fish species across levels of biological organization ranging from biochemical responses to changes at the fish community level. Results from these studies support the development of robust effects-based biological monitoring approaches to assess the effectiveness of regulations and remedial actions for minimizing the effects of MWWE. Understanding the temporal changes in physiological and reproductive parameters across the annual cycle of a sentinel species is necessary to optimize biomonitoring programs. The annual variability in terms of survival, reproduction and energy storage in the Greenside Darter (Etheostoma blennioides), a potential sentinel species for the Grand River, Ontario, was documented at a reference site across two years. Variation in energy storage and reproductive development indicated by somatic indices (i.e., relative organ size) and steroid production suggest that biomonitoring can be optimized for this species by sampling in late fall or early spring (pre-spawning). With this new knowledge, field studies conducted with small bodied species, including Rainbow Darter (E. caeruleum), Brook Stickleback (Culaea inconstans) and Fathead Minnow (Pimephales promelas) have demonstrated that, when sampled during the appropriate season (e.g., pre-spawning), they can be used as effective biomonitoring tools to detect fish responses associated with exposure to MWWEs. Two sentinel fish species, Rainbow Darter and Greenside Darter, were then used to examine the impact of two MWWE discharges on fish in the Grand River, Ontario, relative to reference sites in two seasons (fall and early spring). Fish responses, in terms of energy storage (condition factor, liver size), energy utilization (gonadosomatic indices) and reproduction (in vitro sex steroid production, cellular development and intersex) were assessed at each site. Both sentinel species were longer and heavier downstream of the wastewater outfalls. However, these larger fish did not demonstrate consistent increases in condition and liver somatic indices. MWWE-exposed male Rainbow and Greenside Darters had impaired capacity to produce androgens in vitro, lower gonadosomatic indices and altered sperm cell staging. Exposed female fish also had impaired capacity to produce estrogens in vitro, however, they did not demonstrate differences in oocyte development. Male Rainbow and Greenside Darters collected downstream of both MWWE discharges showed increased incidence of intersex (33 - 100%) in contrast to very low occurrences of this condition in upstream agricultural and urban reference sites. This increased incidence of intersex coincided with reductions in gonadosomatic indices and capacity to produce steroids, demonstrating the ability of MWWE to alter the reproductive systems of these fish. The fish communities downstream of the the MWWE outfalls demonstrated differences in abundance, diversity, and species composition when compared to reference sites. MWWE exposed sites had few of the darter species that dominate the fish community at reference sites. More mobile fish species such as suckers (Catostomidae spp.) and sunfish (Centrarchidae spp.) were more common downstream of the outfalls, with occurances becoming more pronounced downstream of the second sewage discharge. Wascana Creek, Saskatchewan, downstream of the wastewater treatment plant for the City of Regina can be up to 100% treated municipal wastewater. Brook Stickleback and Fathead Minnow exhibited delayed spawning and altered gonadal development downstream of the wastewater outfall. Exposed male Fathead Minnows were feminized, having lower expression of secondary sexual characteristics (i.e., loss of nuptial tubercles, dorsal pad, and dorsal fin dot) and induction of the female egg-yolk precursor protein, vitellogenin. Fathead Minnows also showed cellular damage to the gills and kidneys. These responses indicate exposure to a variety of environmental contaminants in the effluent such as ammonia as well as endocrine disruptors. The potential effect of MWWE discharges in these two Canadian watersheds on fish responses was demonstrated across various levels of biological organization including reduced sex steroid production, altered gonadal development, reduction in gonadosomatic indices, delayed spawning, and changes in fish assemblages. An effects-based monitoring approach using sentinel species can be successfully applied to detect changes associated with MWWE outfalls, as long as sampling of sentinel species is conducted during optimal time periods (i.e., when somatic indices are maximized and variability among individuals is minimized). MWWE can impair the reproductive potential of fish beyond a threshold where impacts are expressed at higher levels of organization such as populations or communities. It is essential to make mechanistic linkages between responses at different levels to determine the overall potential impact of effluents on fish. The collection of responses across multiple levels of biological organization can complement and support development of biomonitoring approaches that are focused at the population and community levels such as those being proposed for MWWE in Canada.

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