This thesis examined whether mental health problems and sexual risk taking were associated in a general population sample and if so, the extent and direction of this association. The thesis begins with a review of theories of risk taking; sexual risk and mental health correlates; and the existing studies linking mental health and sexual risk taking. Three empirical studies were conducted. Study One produced new evidence that a range of psychiatric disorders were linked to early sex (<16 years), risky sex (multiple partners and inconsistent condom use in the past year at age 21) and sexually transmitted infections (STIs) by the age of 21 years. Young people who present with schizophrenia spectrum disorder were also prone to early and risky sex and STIs. Second, depression, the single most common psychiatric problem in the population, was also associated with risky sex and STIs. The risk increased with comorbid psychiatric conditions. Study Two addressed the issue of directionality, specifically examining if childhood behavioural and emotional problems and early adolescent psychiatric disorder predicted later sexual risk taking and STIs. Main findings showed that childhood antisocial behaviour increased the likelihood of risky and early sex, and that low levels of childhood anxiety increased the likelihood of later risky sex and having STIs. Involvement with delinquent peers mediated the association between childhood antisocial behaviour and risky and early sex. To a lesser degree, attachment to parents mediated the association between antisocial behaviour and early sex. These factors did not mediate the association between low levels of childhood anxiety and later sexual outcomes. No associations were found between adolescent psychiatric disorder and later sexual risk taking, with the exception of conduct disorder. However, it is important to note that by excluding the group who had early sex in order to establish temporality, other behaviours of interest exhibited by this group were also excluded. The third study examined whether sexual risk taking was associated with an increased risk of subsequent mental health problems, addressing the issue of directionality in the other direction. Main findings showed that reports of early sex, multiple sex partners and STIs elevated the risk of later substance dependence disorders. Importantly, this association persisted after controlling for �baseline� levels of psychiatric disorder. Early sex also predicted later conduct disorder, even after controlling for prior conduct disorder. In contrast, early sex, multiple sex partners and acquisition of STIs were unrelated to later diagnoses of anxiety or depression. The significant associations with multiple sex partners and STIs were also shown for incident cases of substance dependence. Moderation analyses revealed no differences between the sexes in any of the studies except in Study Three. Specifically, the association between multiple sex partners and substance dependence appeared to be stronger for males than females for up to 10 sex partners and substantially stronger for females than for males beyond ten sex partners. The final chapter in this thesis reviews the strengths and weaknesses of the studies in this thesis before considering the implications of the results for theory, research and practice.

Thesis (M.P.H.M. (Primary Health Care Management))--Mahidol University, 2008. / LICL has E-Thesis 0038 ; please contact computer services.

This thesis encompasses a study of the empty-nest stage of life. For the purposes of this study, the above-mentioned stage was defined as that period in the family when the youngest child matriculates. Thirty-five empty-nest couples were interviewed during 1984, in the city of Port Elizabeth, South Africa. The mean age of the subjects was 49.5, and the standard deviation was 4.9. The couples were asked about their attitudes towards the empty-nest, using a structured questionnaire, the Family Attitude Survey (FAS). This survey consisted of nine-point attitude statements, which focused on theoretical issues pertinent to this stage, viz. children are on-time or off-time with regard to major life events, impact of children leaving home on the parents, degree of parental involvement with children, parent-child relationships, ageing, sexuality, menopause, work-career, and attitudes towards the past, future and death. The general purpose of the present study was to determine the extent to which the empty-nest stage of life constitutes a negative crisis period, or a positive period of stability and growth for the empty-nest parents. Overall, it was concluded that the empirical evidence depicting the empty- nest stage of life as a positive period of stability and growth rather than a negative crisis period, is persuasive for some of the empty-nest parents in the present study, in view of the empirical findings regarding certain of the above-mentioned theoretical issues examined in the present thesis. Notwithstanding this, it was deemed essential to qualify the above conclusion, given the fact that the same and other respondents experienced difficulty with the following issues, viz. children being off-time with regard to major life events, the departure of children from the home, overinvolvement with children, problematic relationships with them, perceptions of themselves as failures as parents, inability to accept their own ageing, problems with changing sexuality, diminishing enjoyment in their occupations, and lack of prospects for future career advancement, negative preoccupation with the past and future, anxiety about death, and an impoverished marital relationship. It was also demonstrated empirically that wives experience particular psychological problems at this time, viz., firstly, they are more adversely affected by their children's departure from the home than their husbands, secondly, they undergo a rehearsal for widowhood more frequently than them, and thirdly, a minority of them are unable to come to terms with the menopause. Finally, the finding that the majority of wives experienced relief with the onset of the menopause when viewed from the perspectives of general emotional impact, children, and the spousal relationship, conflicts with existing theories in this area. However, it is supported by and large by the majority of empirical studies.

The present series of studies was undertaken to determine the effects of peripherally and centrally administered alpha-melanocyte stimulating hormone (MSH) on lordosis and to investigate some of the mechanisms underlying these effects. The results of Experiments 1-5 (Section I) indicated that, when confounding factors were minimized, peripherally administered MSH facilitated receptivity. Centrally administered MSH was found to produce both a long and a short term inhibitory effect. Experiment 6 (Section II) tested the hypothesis that the facilitatory action of peripherally administered MSH was due to an MSH-induced release of progesterone or some other facilitatory adrenal steroid. Results indicated that, while adrenalectomy per se did not inhibit lordosis, it blocked the facilitatory action of MSH, supporting the hypothesis. In Experiments 7-9 (Section III), the role of estrogen and progesterone in the inhibitory actions of MSH was examined. The results of these studies suggested that both estrogen and progesterone are necessary for the short term inhibitory action of MSH. However, the long term inhibitory action of MSH appears to be due, in part, to an MSH-induced decrease in the availability of cytoplasmic progestin receptors. In Experiments 10-15 (Section IV), the role of serotonin in the production of the inhibitory actions of MSH was examined. Parachlorophenyl-alanine (PCPA), a serotonin depletor, was found to prevent the long term inhbitory action of MSH. In addition, the inhibitory effects of PCPA or pirenperone, a serotonin type II receptor antagonist, did not summate with the inhibitory action of MSH. This suggested that serotonin type II receptors were involved in the production of the inhibitory actions of MSH. In Experiment 12, quipazine, a serotonin type II agonist, was found to attenuate fully the short term Inhibitory action of MSH. However, quipazine did not fully attenuate the long term inhibitory action of MSH, suggesting that the short and long term inhibitory actions of MSH are mediated through different mechanisms. This possibility was supported by the results of Experiment 13, which indicated that 20 ng MSH produced a long term, but not a short term, inhibitory effect. The results of Experiment 14 indicated that subthreshold doses of pirenperone and of MSH, when administered together, would inhibit receptivity. Experiment 15 indicated that this inhibition could be attenuated by quipazine. Thus, the following conclusions can be drawn: 1) the facilitatory action of peripherally administered MSH is probably mediated by an MSH-induced release of progesterone from the adrenals, 2) the short term inhibitory action of MSH is mediated, to a large extent, by an MSH-induced decrease in serotonin type II activity, and 3) the long term inhibitory action of MSH is mediated, in part, by an MSH/serotonin-induced decrease in the availability of progestin receptors. In addition, it was hypothesized that: 1) progesterone acts in the MRF to increase serotonin type II activity. Thus, MSH-induced decreases in serotonin type II activity and in progestin receptors probably occur at this location, and 2) estrogen acts in the AH-POA to decrease serotonin type I activity. Therefore, any actions of MSH on serotonin type I activity or on estrogen receptors is likely to occur in this region. Finally, it was suggested that MSH plays a role in the induction and maintenance of pseudopregnancy, thereby providing MSH with a functional role in the regulation of receptive states. / Arts, Faculty of / Psychology, Department of / Graduate

The genetic relationship of anadromous (sockeye salmon) and non-anadromous (kokanee) Oncorhynchus nerka was examined in conjunction with the breeding behaviour of the two forms to determine: (1) if there is evidence of genetic divergence between the forms where they spawn sympatrically; (2) if such divergence is associated with significant premating isolation between the forms and; (3) if premating isolation results directly from the size difference between the forms (sockeye are much larger than kokanee at maturity). Both sexes exhibit spawning territoriality; females establish and defend particular nest sites until death or displacement, males defend access to specific females from other males until the female has spawned out, they are displaced, or leave to compete for additional mates. Size and prior access to resources (mates and/or specific areas) are significant factors in intrasexual aggression in both sexes, with size the major factor in males and prior access the major factor in females. Females accompanied by males larger than themselves lose weight at a faster rate than those accompanied by males smaller than themselves. Weight loss is related to egg loss, indicating females spawn at a faster rate when accompanied by large males. Male mate preference depends on the size of the male. Males of various sizes prefer females of their own size or larger over females smaller than themselves. In contrast, all sizes of males tested demonstrated no preference between females of their own size and those larger. Large males, which have the widest range of potential mates (because of male intrasexual competition and female choice), are the most selective and small males, which have the narrowest range of potential mates, are the least selective. There were significant differences in allele frequencies between sympatrically spawning sockeye and kokanee. However, there were no consistent differences between sockeye and kokanee at any of five polymorphic loci examined. The extent of genetic differentiation between sympatric forms appears to be less than that between neighbouring populations of the same form, judging from an examination of allele frequencies and/or allele compositions. There was extensive assortative mating by form between sockeye and kokanee, which was not totally accounted for by the large size difference. In the two systems examined, males preferred to mate with females of their own form. In sockeye, such preferences are expected because of the size difference between forms. In kokanee, such preferences are not expected based on size alone, suggesting the evolution of premating isolating mechanisms. The degree of premating isolation was positively correlated with the extent of genetic divergence between sympatric forms. The results of this study are related to existing models of sympatric speciation to hypothesize that sockeye and kokanee have diverged in sympatry. The probable differences in selection between the marine and freshwater environments coupled with the assortative mating resulting from their size difference may have caused subsequent genetic divergence. This divergence appears to have been followed by the evolution of premating isolation. / Science, Faculty of / Zoology, Department of / Graduate

This study examines the reproductive and population biology of a long-lived (80-y life span) fish, Sebastes alutus (Gilbert). The objectives of the study were (i) to establish whether groups of adult S. alutus delineated by exploitation histories could be objectively identified as separate sub-populations; (ii) to identify the effects of density-independent mortality caused by exploitation, and relate them to predictions of life history theory (iii) to examine the long-term implications of this mortality pressure on the dynamics of the species; and (iv) to determine the contribution of these results to the development of management programs for this species. A lernaepodid copepod gill parasite (Neobrachiella robusta (Wilson 1912)) was used for the first time as a biological tag to delineate separate sub-populations (stocks) of a commercial fish. Intensity of infection and mean characteristics of the parasite population per fish achieved complete separation between stocks indistinguishable with morphological features. Discriminant analysis showed the parasite also functioned moderately well (34-76% correct classification) as a stock discriminator of individual fish. Use of auxilliary information on the stock identity of hosts improved the classification power of the discriminant function. The density-independent mortality of the commercial fishery on S. alutus has severely truncated the age spectrum of some stocks. Some compensatory growth changes for fish in the stocks under the strongest selection are evident. Examination of the variance structure of female length at age suggests an inverse relation of mortality and growth rate giving rise to smaller, older fish. Smaller, older fish can be accounted for using the same growth function as for the larger fish seen at younger ages, and these similar growth forms can give an aggregate appearance of quadratic growth. Growth changes do not yield significant differences in size at maturity, although age at maturity changes, implying developmental or environmental constraints on maturation. Fecundity estimation methodology was evaluated and the volumetric method previously used for this species found to be inferior to a gravimetric method. Significant differences in fecundity as a function of body variables were found among exploitation groups. Significant differences in oocyte characteristics among stocks were found, with size and age shown to have separable effects. Lightly exploited stocks had significantly higher oocyte quality (as expressed in oocyte weight), effected through differences in the oocyte diameter-oocyte weight relationship. Histological examination details the developmental sequence of oocytes and establishes the maturation period of oocytes and fish. Northern stocks were shown to have significantly larger oocytes. Follicular atresia is suggested as an alternative energy source to the embryo death which has been presented as the source for matrotrophy in this genus. Complete atresia of a ripe oocyte complement was identified in this genus for the first time. No evidence of reproductive senescence was found. The hypothesis of increasing reproductive effort with age, including the independence of age and size effects, was confirmed. No evidence of reproductive cost could be found. The hypothesis of increased reproductive effort earlier in life as a mechanism to offset increased adult mortality was supported. However, the potential of this increase, achieved by growth rate increases, is much less than is needed to compensate for the reduction in lifetime reproductive effort caused by high fishing mortality. The effects of changing mortality rates on several reproductive value indices was examined with deterministic and stochastic simulation models. Cohort reproductive value is the most sensitive of the indices examined and may be the most robust to measurement error. Reproductive value is a more sensitive index of population state than other indices in use and may play a role in determination and evaluation of optimal harvest policies. However, an experimental approach to its use will be required. / Science, Faculty of / Zoology, Department of / Graduate

The purpose of this study is two-fold: (1) to examine the correlation between frequency of sexual activity and general happiness among older Americans and (2) to examine the correlation between frequency of sexual activity and marital happiness among older married Americans. This study employed quantitative data drawn from the 2004-2008 General Social Surveys. Two samples were used. The first sample included all respondents 65 years of age and older with valid responses for the dependent, independent, and control variables. The second sample was a subset of the first and included only the married respondents. Both bivariate cross-tabulations and binary logistic regression analyses were conducted. As expected, the data support a positive association between sexual activity and general happiness in both the total elder sample and the married elder sample (p < 0.05). Also, as expected, the data support a positive association between frequency of sexual activity and marital happiness in the married elder sample (p < 0.05). Even with the introduction of control variables, frequency of sexual activity was found to be a significant predictor of both general and marital happiness (p < 0.05). This study suggests that sexual activity does indeed contribute the happiness and well-being of older Americans.

No description available.

Double standard effects in inferences about quality of parenting and adult sexual outcomes for children were investigated under five conditions of single-parent sexual behavior. The sample comprised six hundred married parents from three major metropolitan areas in Texas. Subjects were administered a scenario about a hypothetical single parent family. The scenario varied with respect to parent gender, child gender, and type of parental sexual activity (e.g., abstinence, limited affairs away from home, involvement with a live-in lover, frequent partners spending the night, and a control condition containing no sexual message). Subjects were asked to rate a parent from the scenario on quality of parenting and predict the adult sexual behavior of the child. Hypothesized double standard effects did not emerge. A double standard in judgments about sexually active single parents and parenting did appear. Main effects were found for child gender and sexual lifestyle of the parent (e.g., parents with boys rated less favorably than parents with girls; promiscuous fathers were rated lower than promiscuous mothers). Several interaction effects among parent gender, child gender, and sexual lifestyle condition were also found (e.g., promiscuous parents were rated lower as parents and seen as negatively influencing the child's sexual development). Recommendations for future research include refining the two scales used in this study; extending the study to include data from single parents; examining whether the judgments of sexually active single parents affect the quality and quantity of interactions others have with either the parent or child.

No description available.