Browsing by Subject "Reproduction"
Now showing 1 - 20 of 21
Results Per Page
Sort Options
Item A comparison of semen thawing for artificial insemination in cattle.(2011-05-26T18:13:05Z) Kaczyk, Brittni L.; Kaczyk, Brittni Lanay; Serrano, Gabriela I.; May, Brain J.; Scott, Cody B.; Salisbury, Michael W.; Angelo State University. Department of Agriculture.Beef cows (n=23) were used to compared conception rates of two different thawing methods used for artificial insemination (AI). Cows were divided into the treatment or control group based on time of estrus. In the treatment, frozen semen was placed directly into the AI gun and inserted into the female for deposition after a minimum of 30 seconds. The control females experienced the typical thawing process of semen straws placed in a water bath for a minimum of 30 seconds, then loaded into the AI gun and deposited into the uterus of the female. Conception rates were similar between semen thawing methods (P > 0.51). Additionally, the study analyzed semen motility using the two different thaw methods and found no difference (P = 1.0). In conclusion, thawing semen directly in the reproductive tract of the female provides the same conception rates as traditional thaw methods.Item Accumulation and effects of HMX in the green anole (Anolis carolinensis)(2007-08) Jones, Lindsey E.; McMurry, Scott T.; Lovern, Matthew; Cobb, George P.; Smith, Philip N.; Anderson, ToddThe use and subsequent environmental contamination of energetic compounds is an ever increasing international concern. Perhaps one of the greatest lapses in knowledge, and therefore threats to the natural environment, of these compounds is their toxicity to reptiles, particularly with respect to reproduction. To that end, a three-part study was conducted in an effort to define the role of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX, High Melting Explosive), one of the top four explosive compounds of the twentieth century, in the reproductive toxicology of the green anole (Anolis carolinensis), a common reptilian model species. First, the acute oral toxicity (LD50) was measured in adult anoles using the up-and-down method described by the Organization for Economic Co-Operation and Development and United States Environmental Protection Agency. Then, part two of the study used artificially contaminated nesting media to assess accumulation of HMX into eggs at different combinations of incubation time and concentration. Also, initial growth parameters were measured for all hatchlings. The third part of the study was designed to assess HMX transfer from the diet of adults to eggs. In addition to assessing accumulation, hatching rates of eggs, growth rate of hatchlings, and signs of toxicity and abnormal reproductive function in adults were monitored. HMX was not acutely toxic to adult anoles and the LD50 was estimated at greater than 2,000 mg HMX/kg body weight. A dose-dependent accumulation of HMX into the egg was observed, though no significant developmental differences were observed among treatment groups. Exposed adults also exhibited dose-dependent accumulation of HMX, as well as treatment-related food aversion. From these studies it can be concluded that HMX readily accumulates in reptiles both directly (via ingestion of contaminated prey and/or contact with contaminated soil) and indirectly (via maternal transfer). Further study to determine the effect of HMX over two breeding seasons may be warranted.Item Belly : blackness and reproduction in the Lone Star State(2014-05) Cole, Haile Eshe; Vargas, João Helion CostaThis dissertation begins with the finding that in the United States Black women are four times as likely to die due to pregnancy related complications than their white counterparts as well as the finding that Black children are 2 to 2.5 times as likely to die before their first birthday. Given this, the project examines the intersections between Black women’s reproductive experiences and the condition of reproductive health and access in the state of Texas. In order to accomplish this, the research situates the grassroots organizing work of a collective of mothers of color alongside national and state level legislation and data about maternal and infant health disparities. The work not only situates ethnographic experiences within the larger repertoire of quantitative health literature on disparities but it also historicizes the work alongside Black Feminist theories of the body, history, and Black women’s reproduction. Drawing from extended participant observations, interviews, focus groups, policy research, statistics, and archival work, this project unpacks the large disparity that exists in maternal and infant health outcomes for African-American women and the ways in which policy, community organizing, and other geo-political factors contribute to, mediate, or remedy this phenomenon. Given the data presented, this projects suggests that (re)creating supportive communities and support networks may be an effective way of mediating stress caused by long-term exposures to racism and ultimately healing the negative maternal health outcomes for black women.Item Colonizing the womb : women, midwifery, and the state in colonial Ghana(2011-12) Amponsah, Nana Akua; Falola, Toyin; Walker, Juliet E; Charumbira, Ruramisai; Jones, Omi Osun Joni L; Obeng, Cecilia S; Denbow, James RThis dissertation explores the British colonial government’s attempt to reconstruct women’s reproductive behaviors in colonial Ghana through the sites of maternal and infant welfare services and western midwifery education. In the early 1920s, the fear that the high maternal and infant mortality rates in the Gold Coast would have repercussive effects on economic productivity caused the colonial government to increasingly subject women’s reproduction to medical scrutiny and institutional care. I argue that female reproduction was selected as a site of intervention because the British colonial government conceived of it as a path of least resistance to social reconstruction, economic security, and political dominance. The five chapters have been designed to analyze colonial reproductive intervention as a socio-economic and political exigency of colonial rule. This dissertation speaks to the fact that cross-culturally, the female body has been politicized through narratives of power, culture, tradition, modernity, race, disempowerment, and empowerment.Item Conception rate differences in sexed vs. non-sexed semen(2011-06-21T22:18:13Z) Brooks, Kayla L.; Brooks, Kayla Lynn; Salisbury, Michael; Ammerman, Loren; Engdahl, Gil; May, Brian; Angelo State University. Department of Agriculture.The objective of this study was to determine if sexed semen has similar conception rates as non-sexed semen. Eighty-four Angus females from the Angelo State University’s Management, Instruction and Research Center were synchronized at the beginning of this study; however, only 54 showed signs of estrus and were artificially inseminated (10 Heifers and 44 multiparous cows). The 54 females were split randomly into three different treatment groups. Heifers and cows in treatment one were inseminated with Y-bearing sexed semen. Females in treatment two were inseminated with X-bearing sexed semen; while the last treatment was our control which received non-sexed semen. Results in heifers and cows were similar, and no differences were noted among the three treatment groups (P>0.5). Differences might be noted with a larger number of females. Date of parturition was estimated using ultrasound, and is a viable management tool because it is possible to predict, on average, within 9 days of parturition with a 36 day maximum and an exact prediction for the minimum.Item Disciplining mommy : rhetorics of reproduction in contemporary maternity culture(2013-08) Mack, Ashley N.; Cloud, Dana L.In this dissertation, I argue that the maternal body is a chief site of discursive political and cultural struggle over gender, family, and work in a neoliberal America. I consider contemporary discourses of maternity, an aggregate I call maternity culture, as cultural products and rhetorical expressions of the antagonistic arrangements in contemporary capitalism since the neoliberal turn. The complexities of maternity culture discourses can therefore be better understood when they are historicized alongside changing economic and political realities. Using materialist feminism as my primary methodology, I contend that maternity culture discourses express the ethics of neoliberalism including the privatization of social/political responsibility and self-actualization through entrepreneurialism and labor, while simultaneously justifying the intensification of maternal labor and the continued surveillance of women's bodies. I argue that maternity culture discourses are, therefore, rhetorics of reproduction and reproducing rhetorics. That is to say, they are a part of a larger set of discourses about the reproductive function that are themselves caught in the logics of capital that may result in the reproduction of unequal arrangements in material and symbolic life. In order to illuminate how maternity culture operates in neoliberal public life as a reproducing rhetoric, I provide a historical analysis of rhetorics of women's health, and analyze two case studies involving discourses surrounding breastfeeding and natural childbirth, major sites of struggle within maternity culture.Item Diversity and evolution of reproductive systems in Mycocepurus fungus-growing ants(2010-05) Rabeling, Christian; Mueller, Ulrich G.; Hillis, David M.; Bolnick, Daniel I.; Schultz, Theodore R.; Singer, Michael C.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.Item Effect of cottonseed meal consumption on performance of female fallow deer(Texas A&M University, 2004-09-30) Mapel, Steven LeeThe objectives of this study were to determine the effects of gossypol ingestion on reproductive function and productivity of female fallow deer (Dama dama) by measuring endocrine function, pregnancy rates, and body weights of does and fawns. Sixty multiparous fallow does were randomly allotted into three groups corresponding to treatment diet that varied in respect to gossypol content. The does were then separated by treatment into pastures containing two fallow buck sires per pasture. The control group (SBMG), (containing no gossypol in diet) received 362 g soybean meal (SBM) ?animal-1?day-1. The low gossypol group (CSML) was fed 227 g cottonseed meal (CSM; 0.09% free gossypol; determined by HPLC) and 181 g SBM?animal-1?day-1. The high gossypol group (CSMH) received 454 g CSM?animal-1?day-1. Diets were fed daily from 6/16/2003 to 11/20/2003. Blood samples were collected weekly from 8/14/2003 to 11/20/2003 for progesterone and gossypol analysis. Fawns born in June and July of 2003 were weaned 9/18/2003. Bucks were fitted with marking harnesses for the duration of the breeding season and heat marks were recorded daily for estrus detection. Ultrasonography, for pregnancy detection, was performed on 11/20/2003 and 12/15/2003. All groups lost weight from 8/14/03 to 11/20/03. SBMG lost less (P<.05) weight than either CSML or CSMH. Final body weights were 2% greater (P<.02) in SBMG than in CSML or CSMH. Body condition from 8/14/03 to 11/20/03 did not differ (P>.1) between treatments. The pregnancy rate for all groups was 100%. There was no difference (P>.01) in time from weaning to conception (23 d) between treatments. Does in CSMH exhibited decreased (P<.02) progesterone concentrations. Consumption of CSM (free gossypol in amounts up to 0.81 mg?kg-1BW; 0.41 g?animal-1?day-1).did not appear to affect reproductive performance of fallow deer.Item Effect of Neofat on offspring sex ratios in Rambouillet and Suffolk sheep.(2011-05-10T21:35:24Z) Lange, Sarah E.; Lange, Sarah; Branham, Loree A.; Engdahl, Gril R.; Pier, Charles A.; Angelo State University. Department of Agriculture.Maternal diet and body condition are conceivably the most studied factors influencing sex ratio. The objective of this study was to determine if Neo-fat® influences offspring sex ratio in Rambouillet and Suffolk sheep. Ewes were randomly assigned to one of two treatments (n = 46). Treatment 1 consisted of a basal diet to serve as a control, and Treatment 2 consisted of the basal diet plus Neo-Fat fed at 0.46% of body weight. Ewes were bred after four weeks of feeding and continued to be fed for an additional two weeks. Blood samples were taken at breeding to determine differences in NEFA concentrations in serum. Results were only considered for ewes lambing as a result of being bred on the first estrus cycle and indicated no differences among NEFA concentrations, lamb sex ratios or lamb birth weights (P > 0.05).Item Effects of Compensatory Gain on Success of a 7-day Co-Sync+CIDR Artificial Insemination Protocol in Beef HeifersHughes, Kaitlyn; Runyan, Chase A; Scott, Cody B; Salisbury, Micheal W; Muelsch, Elisabeth-ChristineAngus heifers born in the spring of 2014 (n=38) were used to evaluate the effects of compensatory gain on the pregnancy status using a 7-day Co-Sync+CIDR® estrous synchronization protocol followed by a fixed-timed artificial insemination (FTAI) procedure. The heifers that were kept at the Management Instruction and Research Center (MIR group) were managed to a limited level of nutrient availability and experienced limited growth rate after weaning. Then the MIR group was placed in feeding pens to obtain an accelerated rate of gain to capture the compensatory gain phenomenon. Heifers concurrently managed at a collaborator herd in Fredericksburg (FRED group) were allowed access to oat forage, self-limiting supplementation, and free choice sorghum hay through the entirety of the project to suffice nutrient demands, not limiting growth rate. It was observed that even though differences in growth rate were significant, there was no difference in the pregnancy status from the FTAI.Item Evaluating the Reproductive Habits and the Breeding Season of the Hog-nosed Skunk (Conepatus leuconotus)Ellsworth, Zachary Tate; Dowler, Robert C; Skipper, Ben R; Negovetich, Nicholas J; Taylor, William AI collected data to assess the times when the hog-nosed skunk, Conepatus leuconotus, is reproductively active and compared these times to its reported breeding season. I analyzed data from 752 museum collection specimens from six countries to determine sex ratio and discern in which months hog-nosed skunks had the highest activity, as indicated by collection date. Collection peaks were different for males and females, but were not exclusively seen during the reported breeding period. Testes measurements were analyzed for a smaller subset of 100 males from the United States collected throughout the year. Data were compared by collection month to determine if there was a significant difference in size of the testes and reported mating season. There was neither a difference in relative testis size among months, nor between the months of the reported breeding period and non-reproductive months. Reproductive behavior occurs outside the reported breeding period for C. leuconotus.Item Evaluation of Performance Traits in Brahman Cattle: Blood Parameters, Calf Temperament, Residual Feed Intake, and Bull Reproductive Development(2010-10-12) Matheney, Kara J.The objectives of these studies were (1) evaluate the relationship between temperament, blood parameters, and performance in Brahman calves (n = 300); (2) evaluate the relationship between residual feed intake (RFI) and reproductive development in Brahman bulls (n = 41). Serum was collected at 24 h and d 21 to 24, and analyzed for total protein (TP) immunoglobulin G (IgG), and cortisol (CS). Calves were weighed at 24 h, weighed and evaluated for temperament using exit velocity (EV) at d 21 to 24, and at 28 d intervals thereafter. Beginning 28 d prior to weaning, and at 28 d intervals through 56 d post-weaning calves were evaluated for pen score (PS) used to calculate temperament score (TS = (EV+PS)/2). The average TS from 28 d prior to weaning and weaning was used to generate temperament groups; calves 1 SD below the mean being calm, those 1 SD above the mean being temperamental and all remaining classified as intermediate. Calf TS influenced WW (P = 0.04) and ADG from birth to weaning (P = 0.03). Serum TP at 24 h affected (P < 0.05) WW and ADG from birth to weaning. Serum IgG at 24 h affected (P = 0.03) WW. Brahman bulls (n = 41) were evaluated for RFI, insulin-like growth factor I (IGF-I), temperament, reproductive development, and ultrasound carcass traits. Serum was collected at d 0 and d 70 of the feeding trial and analyzed for IGF-I. Bulls were classified as efficient, intermediate, or inefficient (RFI classification method I) and as efficient or inefficient (RFI classification method II). Bulls were evaluated for temperament at weaning using TS. Temperament influenced (P < 0.05) IGF-I concentrations at d 0. Reproductive development was not affected (P > 0.05) by TS. Residual feed intake classification did not influence (P > 0.05) age at reproductive milestones. Ultrasound carcass traits were not affected by TS or RFI. Serum TP at 24 h was a viable indicator of future growth performance. Temperamental animals had lower growth rates in both studies. Reproductive development was not affected by RFI. BW at reproductive milestones was lower in temperamental bulls.Item Fine structure of implantation and the corpus luteum in the California leaf-nosed bat, Macrotus californicus(Texas Tech University, 1975-08) Bleier, William JosephNot availableItem Genomic Insights into Sexual Selection and the Evolution of Reproductive Genes in Teleost Fishes(2012-10-19) Small, ClaytonSexual selection has long been a working explanation for the elaboration of appreciable traits in plants and animals, but the idea that it is an equally potent agent of change at the level of individual molecules is relatively recent. Indications that genes associated with reproductive biology evolve especially rapidly planted this notion, but many details about the genomics of sex remain elusive. Numerous studies have characterized rapid sequence and expression divergence of sex-related molecules, but few if any have demonstrated convincingly that these patterns exist as a result of sexual selection. This dissertation describes several genome-scale studies related to reproduction and the sexes in teleost fishes, a group of animals underexploited in regard to this topic. Using commercial microarrays I measured the extent of sexually dimorphic gene expression in the zebrafish, Danio rerio. Sex-biased patterns of gene expression in this species are similar to those described in other animals. A number of genes expressed at high levels in ovaries and testes relative to the body were identified as a product of the study, and these data may be useful for future studies of reproductive genes in Danio fishes. In a second study, the recent advent of high throughput cDNA pyrosequencing was leveraged to characterize the relationships between tissue-, sex-, and species-specific expression patterns of genes and rates of sequence evolution in swordtail fishes (Xiphophorus). I discovered ample evidence for expression biases of all three types, and a generally positive but idiosyncratic relationship between the magnitude of expression bias and rates of protein-coding sequence evolution. Pyrosequencing of cDNA was also used to explore the possibility that postcopulatory sexual selection drives the rapid evolution of male pregnancy genes, a novel class of reproductive molecules unique to syngnathid fishes (seahorses and pipefishes). Genes differentially expressed in the male brooding tissues as a function of pregnancy status evolve more rapidly at the amino acid level than genes exhibiting static expression. Brooding tissue genes expressed during male pregnancy have evolved especially rapidly in polyandrous lineages, a finding that supports the hypothesized relationship between postcopulatory sexual selection and the adaptive evolution of reproductive molecules.Item Grim Sleeper : gender, violence, and reproductive justice in Los Angeles(2014-08) Grigsby, Julie Renee; Vargas, João Helion Costa; Ali, Kamran; Smith, Christen; Browne, Simone; Rodriguez, DylanDiscussions of South Los Angeles often reflect dystopic conditions of black communities as supine beneficiaries of endless social welfare living in seemingly malignant spaces where poverty and disease darken corners of an otherwise ideal city. This dissertation contributes to literature on urban violence, public health, and nonprofit studies through a feminist ethnography of black women’s community organizing. The Grim Sleeper murders spanned a 25-year period, marking two decades of violence against black women’s bodies in South Los Angeles. Slow moving police investigations began in 1984, were colored by depictions of murdered black “prostitutes,” which spurred a community response by women activists, yet the suspect was not arrested till 2010. Just a year before, in 2009, public health research for Los Angeles County, revealed staggering disparities in black women’s reproductive health, including: a maternal mortality rate nearly four times all other racial groups and rising STI’s among adolescents and women between the ages of 14 - 25. Again, with little comment or action this time in public health, the lives and bodies of black women continued to be in precarious positions. In national and popular debates of reproductive rights discussion surrounds abortion legislation, failing to address a range social inequalities that cut into reproductive lives of black women. I explore, the Grim Sleeper as not just a named serial killer but as characteristic of latent state responses to reproductive health challenges experienced by black women. Activist’s response to this parallel and cyclical lived experience of gendered violence against black bodies is at the center of my research. I argue that blackness, neither marginal nor invisible, is principal to understanding how race and social inequalities effect lived geographies. I closely examine; (1) the nature of reproductive justice within a community organization and (2) the ways California’s economic downturn affects approaches to social transformation through nonprofit and advocacy work. (3) A murderer’s twenty-five year history of targeting black women and the silence that surrounded it as reflective of state approaches to the lives of black women. Utilizing public health, policy, archival, oral history and ethnographic data my dissertation proposes the advancement of a reproductive justice standpoint by situating black women’s agency as a starting point for well-being and community health agendas.Item Heterosis and heterosis retention for reproductive and maternal traits in Brahman - British crossbred cows(Texas A&M University, 2005-02-17) Key, Kelli LorenReproductive, maternal, and weight traits were analyzed for Angus (A), Brahman (B), and Hereford (H) straightbred cows; F1 and F2 BA and BH cows; and 3/8 B 5/8 A first (Bn) and second (Bn2) generation cows in Central Texas. Heterosis was estimated for calf crop born (CCB), calf crop weaned (CCW), and cow weight at palpation (PW) by linear contrasts within cow breed groups. F1 BA cows expressed heterosis (P<0.01) for CCB (0.10) and CCW (0.11), while F2 BA cows expressed negative heterosis (P<0.10) for CCB (-0.06) and CCW (-0.07). F1 BH cows expressed heterosis (P<0.001) for CCB (0.15) and CCW (0.16), and F2 BH cows retained F1 heterosis (P<0.001) for CCB (0.13) and CCW (0.15). Bn2 cows expressed heterosis (P<0.01) for CCB (0.14), but Bn cows did not express heterosis (P>0.10) for CCB or CCW. Only the F1 BA (22.9 kg) and F2 BH (42.1 kg) groups expressed heterosis (P<0.10) for PW. Bn2 cows (-65.7 kg) expressed negative heterosis (P<0.01) for PW. Heterosis for calf survival (CS), birth weight (BW), and weaning weight (WW) was estimated by linear contrasts within calf breed groups for B- and H-influenced calves. F1 BH (0.11) and F2 BH (0.14) calves expressed heterosis (P<0.01) for CS. None of the groups expressed heterosis (P>0.10) for BW, but B-sired F1 BH calves were 5.5 kg heavier (P<0.01) than H-sired F1 calves at birth. F1 BH (22.4 kg) and F2 BH (26.2 kg) calves expressed heterosis (P<0.001) for WW, and H-sired F1 BH calves were 20.7 kg heavier (P<0.10) than B-sired F1 calves at weaning.Item Lipid utilization in the reproductive effort of female Kinosternon flavescens(Texas Tech University, 1983-05) Long, David RobertKinosternon flavescens maintains the highest lipid index of all reported turtles. Juveniles had larger lipid stores than females during most of the activity period. Chelonian lipid reserves show annual variation with egg development constituting a primary demand for stored lipids. Lipid incorporation in ovarian follicles occurred at a constant rate and at direct expense of the female's lipid reserve. The mean lipid index of oviducal eggs was higher than that reported for other chelonians. No correlation was evident between the lipid index of females and that of their oviducal eggs. Individual egg mass and clutch size increased with size of the female. The lipid index of oviducal eggs increased with clutch size.Item Molecular mechanisms of phenotypic plasticity in Astatotilapia burtoni(2011-12) Huffman, Lin Su; Hofmann, Hans A.; Crews, David; Gore, Andrea; Ryan, Michael; Zakon, HaroldThe ability of an animal to respond and adapt to stimuli is necessary for its survival and involves plasticity and coordination of multiple levels of biological organization, including behavior, tissue organization, hormones, and gene expression. Each of these levels of response is complex, and none of them responds to stimuli in isolation. Thus, to understand how each system responds, it is necessary to consider its role in the context of the entire organism. Here, I have used the African cichlid fish Astatotilapia burtoni and its extraordinary phenotypic plasticity to investigate how animals respond to a change in social status from subordinate to dominant and attempted to integrate these multiple levels of biological response, as well as the roles of several candidate neuromodulators,. First, I have described how male A. burtoni become more aggressive and reproductive during their transition to dominance as well as increasing circulating levels of testosterone and estradiol and the histological organization of their testes. I then mapped the distribution of expression of two behaviorally relevant neuropeptides, arginine vasotocin and isotocin, and their respective receptors, throughout the A. burtoni brain, and found that they were highly expressed in several brain areas important for social behavior and decision-making. I then investigated the role of arginine vasotocin in social status and behavior via pharmacological manipulation and qPCR, showing the importance of arginine vasotocin in controlling the transition to dominance. Lastly, I investigated the role of aromatase, testosterone, and estradiol in male A. burtoni, both in stable dominant males and in males as they transition to dominance, using pharmacological manipulation and quantitative radioactive in situ hybridization, illustrating that estradiol synthesis during dominance is dependent on aromatase activity and necessary for aggressive behavior.Item Parents Talking About the Birds and the Bees With Their Elementary School Aged Children: A Naturalistic Study(2013-07-22) Reichel, LoriThis dissertation presents three separate studies exploring parents? perceptions and recommendations for communicating with their third, fourth, and fifth grade children about human sexuality. First, a systematic literature review is presented summarizing past qualitative studies completed in the United States focusing on parents with children aged 18 years and under. This review summarizes (1) demographic information of parents from past studies, (2) perceived communication barriers experienced by parents regarding sexuality communication, and (3) perceived communication facilitators experienced by parents regarding sexuality communication. Second, noting the lack of research within a specific population of parents in the United States, a naturalistic study of parents with children in the third, fourth, and fifth grade is presented. Utilizing an emergent design, one-on-one interviews were conducted with 20 parents living in a town in central Texas. By coding collected data, a thematic analysis was used to summarize emergent themes. Themes included techniques parents utilized to have parent-child conversations about sexuality and discussed topics. Although different techniques and topics were raised, parents showed overall inconsistency in experiences or past discussions. Third, using data from the same 20 interviews, themes emerged from parents regarding recommendations. These included the recommendations that a booklet with age appropriate information on sexuality topics be developed for parents and parent workshops or classes covering age appropriate sexuality knowledge as well as techniques to use in parent-child communication be offered. Schools were the recommended source for these resources. Parents also shared feedback on the newly released National Sexuality Education Standards. Comparing past parent-child conversations on sexuality topics to the NSES, certain topics were discussed yet inconsistency was shown. In addition, parents disagreed on specific standards including those pertaining to the functions of reproductive parts, reproduction, and same sex orientation. Implications of this study are that parental resources are needed to help parents communicate with their children about sexuality beginning at a young age. And, for those resources already existing, including workshops, books, and on-line sources, parents need to be made aware of their existence. In addition, future research is needed to explore if younger children are learning from parent-child conversations about sexuality.Item The roles of estradiol-17 beta and prolactin in uterine gland development in the neonatal ewe(Texas A&M University, 2005-11-01) Carpenter, Karen DeniseEndometrial glands are required for adult uterine function and develop post-natally in mammalian species. Therefore, studies were conducted using neonatal ewes as a model to determine: 1) the roles of estradiol-17-alpha and estrogen receptor-alpha (ER-beta) in endometrial gland development; 2) the role of ovaries in endometrial gland development; 3) the role of prolactin in endometrial gland development; and 4) factors regulating prolactin receptor expression in endometrial glands. Study one determined the effects of neonatal exposure of ewes to estradiol-17-alpha valerate (EV); EM-800, an ER-beta antagonist; or CGS-20267, an aromatase inhibitor on endometrial gland development. Results indicate E2-17-alpha does not regulate endometrial gland differentiation or development. Additionally, ER-beta does not regulate primary differentiation of glandular epithelium, but does influence coiling and branching morphogenesis of endometrial glands. Study two determined the effects of ovariectomy on endometrial gland morphogenesis. Results suggest that the ovary and, thus, an ovarian-derived factor(s) regulate, in part, the coiling and branching of endometrial glands. Expression of subunits of activin, follistatin, and inhibin in the neonatal ovine ovary in addition to modulation of the components of the activin/follistatin system in the uterus of ovariectomized ewes supports the hypothesis that the ovarian factors that influence endometrial adenogenesis in the neonatal ewe may be activin, follistatin, and/or inhibin. Studies three and four determined the role of prolactin in endometrial adenogenesis in the neonatal ewe. Studies in which either hypoprolactinemia or hyperprolactinemia were induced indicate that prolactin regulates ovine endometrial adenogenesis in the neonatal ewe. The aim of study five was to determine transcription factors that regulate the glandular epithelium specific expression of prolactin receptor. Prolactin receptor exon 2 was cloned and sequenced, but no identifiable exon 1 or promoter was found. Additionally, many bovine contigs containing portions of the prolactin receptor gene were identified suggesting the bovine genome will be a useful tool as it becomes more complete. These results indicate ER-beta, prolactin and prolactin receptor, along with an unidentified ovarian factor(s), influence endometrial gland development in the neonatal ewe; however, exposure of the neonatal ewe to exogenous estradiol-17-alpha prevents differentiation and development of endometrial glands.