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The aims of this project were to investigate the binding characteristics of the cytosolic oestrogen receptor in the uterus, brain and thymus of immature Wistar rats. The specificities of the receptor in the uterus are well established. The specificities of the cytosolic receptor in the uterus and thymus of immature female Wistar rats were tested against a range of steroids and the values found for the thymus compared with those for the uterus. The concentrations and dissociation constant (Kd) of the cytosolic oestrogen receptor were determined in uterus, brain and thymus of male and female rats at 5,18 and 30 days of age. Clomiphene citrate (CC), an oestrogen antagonist/partial agonist, oestradiol (E2), CC+E2 or 4-hydroxyandrostenedione (4-OHA), an aromatase inhibitor, were administered to animals at 15 days in order to study the effects of these compounds on receptor binding characteristics at 30 days. Significant differences in specificity were found between the thymus and uterus, the cytosolic oestrogen receptor in the thymus exhibited significantly higher affinity for corticosterone than it did in the uterus. Male animals were heavier than females at 30 days. Uterus and thymus weights increased exponentially between 5 and 30 days. The tissue-to-body weight ratio increased in uterus between 18 and 30 days and increased in the thymus in both sexes between 5 and 18 days. In males at 30 days, the tissue-to-body weight ratio of the thymus was significantly lower than in females of the same age. Cytosolic oestrogen receptor concentrations in the uterus, brain and thymus differed between some age and/or sex groups. Cytosolic oestrogen receptor concentrations increased exponentially in the uterus between the different age groups. Cytosolic oestrogen receptor concentrations in both thymus and hypothalamus at 5 days were significantly higher in females than in males of the same age group. No differences in cytosolic oestrogen receptor concentrations were found between the sexes in the cortex at 5 and 18 days but at 30 days, receptors were not detectable in this brain area. The Kd for moxestrol, a synthetic oestrogen agonist that is not bound by alphafetoprotein present in the blood of immature rats, was similar in all tissues. E2 and CC+E'-' treatmentsr esulted in decreasedb ody and thymus weight in both sexes,i ncreased uterus weight and decreased thymus weight in both sexes but led to increased uterus weight. CC treatment decreased the concentration of the receptors in the female thymus only-, E2 and CC+E2 treatments decreased the concentratIon of the receptor to levels that were undetectable in hypothalamus and thymus in both sexes, 4-OHA treatment increased thymus weight and cytosolic receptor concentrations in the hypothalamus and thymus of males only. These results suggest that cytosolic oestrogen receptors in uterus, brain and thymus are similar and that sex differences in these tissues are mediated by differential exposure to oestradiol during the early postnatal period. The thymus is crucial to the development of the immune response. The finding that the cytosolic oestrogen receptor differed from the uterus receptor in its affinity for corticosterone and that sex differences in cytosolic oestrogen receptor concentrations were present in the thymus at 5 days could be relevant to the sex dimorphisms that exist in autoirnmune disease manifestation.

Thesis (Ph.D.) - University of St Andrews, August 2008.

Thesis (M.S.)--Marshall University, 2004. / Title from document title page. Document formatted into pages; contains viii, 72 p. including illustrations. Includes abstract. Includes bibliographical references (p. 33-37).

Thesis (Ph. D.)--Carleton University, 1988. / Also available in electronic format on the Internet.

Thesis (MSc)--University of Stellenbosch, 2005. / Bibliography. Also available via the Internet.

Bibliography: pages 128-138. / This study focuses on the mating dynamics of South African forest millipedes Centrobolus (Diplopoda: Spirobolida: Pachybolidae). The main objectives were to investigate the two most common mechanisms of sexual selection, sperm competition and cryptic female choice. The approach was to (1) quantify sexual dimorphism and find the selection pressures operating on the sexes, (2) determine the functional significance of male and female genitalia, (3) understand why there should be a conflict of sexual interests in prolonged copulations, and (4) resolve the mechanisms of sperm competition and cryptic female choice by comparing male mating strategies and sperm precedence to female mating strategies and sperm usage. All hypotheses tested in this thesis are centered on whether there is a conflict of interests between the sexes.

Estimating the sex of unknown human skeletal remains is important to the fields of forensic anthropology, bioarchaeology, and other specialties. I studied sexual dimorphism on the first and second ribs to estimate sex from skeletal remains. I employed two approaches. I used geometric morphometrics to analyze landmark and semilandmark coordinate points to examine the overall shape of the ribs. I also examined the sternal end of the ribs for size using the superior-inferior height (SIH) and anteriorposterior breadth (APB) in a binary logistic regression (BLR) model. Differences in male and female first and second ribs are undetectable when landmark coordinate points are used to capture shape variability, but significant differences in the shape of the ribs, however, are detected through the use of semilandmark coordinate points. Using semilandmark points to estimate sex presented an accuracy rate of 80.7% from the first rib, and 72.9% from the second rib. The use of the sternal end presents consistent results in its ability to estimate sex with an accuracy rate of 84.2%. The BLR model reveals significant differences between males and females than the geometric morphometric approach; it is more applicable for discerning sexual dimorphism of unknown individuals. This study reveals that while geometric morphometrics provides a powerful approach to assessing morphological differences, it is not always better than simpler methods, in this case, simple measurements analyzed through BLR. / Includes bibliography. / Thesis (M.A.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection

My dissertation focuses on the factors that influence variation in female reproductive success in plethodontid salamanders and in toads. Variation in reproductive success fuels evolutionary change. Although, females often have been overlooked in studies of reproductive success due to perceived lower levels of variation when compared to variation in male reproductive success, understanding factors influencing variation in female reproductive success is critical for several reasons. First, female reproduction is usually the limiting factor on population growth. Second, the factors affecting female reproduction provide the impetus for current and evolving patterns of sexual dimorphism. Lastly, male reproductive success inevitably is determined by the reproductive success of the females with which they mate. Recent theoretical developments of sexual conflict have contributed significantly to a renewed emphasis on studies of female reproductive success. Sexual conflict theory elucidates important factors, from the perspective of females, affecting female behavior and reproductive success. Sexual conflict assumes that a female will benefit, in terms of reproductive success and offspring viability, when she is able to freely choose among males, unconstrained by social and environmental factors. Female choice would be constrained if a non-preferred male (i.e., one that would be rejected by a freely choosing female) coerced a female to mate in order to increase his own mating success. The dynamics between discriminating females and non-preferred males will lead to a coevolutionary "arms race", referred to as sexual conflict. From this perspective, secondary male traits may not reflect their intrinsic quality, but rather their ability to manipulate or coerce female mating decisions. The current debate lies in the importance and pervasiveness of sexual conflict. To address the current view of sexual conflict, I investigated whether sexual conflict plays a role in the mating systems of amphibians. In particular, my results support the main assumption that females benefit from freely expressed female mate choice in toads. In addition, I explored the potential influence of sexual conflict in plethodontid salamanders. During mating trials, I documented novel female courtship behaviors. I also examined the effects of male courtship pheromones on female reproductive success to assess the potential role of male pheromones in sexual conflict. My results suggest that sexual conflict also may be an important factor in plethodontid mating systems. My investigations of sexual conflict theory have provided new insights and novel predictions for understanding sexual selection and sexual dimorphism. / Graduation date: 2005

Thesis (Ph. D.)--University of Kentucky, 2004. / Includes abstract and vita. Includes bibliographical references (p. 191-198). Also available in PDF format via internet.