Estressores múltiplos, decorrentes de atividades antropogênicas, podem gerar efeitos combinados em organismos marinhos. Efeitos da acidificação oceânica associados a outros impactos antrópicos são pouco compreendidos, especialmente em zonas costeiras. Nestas regiões, o sombreamento causado por infraestruturas, como portos, pode potencialmente interagir com a redução do pH da água do mar e afetar populações de crustáceos. O objetivo foi avaliar os efeitos de pH reduzido e sombreamento na mortalidade, crescimento, calcificação e respostas comportamentais de deslocamento a odores de predadores vivos (sinal de perigo) e gastrópodes mortos (sinal de recurso disponível) usando juvenis do ermitão Pagurus criniticornis, coletados na Baía do Araçá (São Paulo, SE Brasil). Após 98 dias de experimento, os estressores apresentaram interação significativa sobre a mortalidade dos organismos, além de efeito aditivo sobre o crescimento. A calcificação não diferiu entre tratamentos, indicando que indivíduos foram capazes de manter a calcificação em condições de pH reduzido. Quando expostos a odor de predadores, o deslocamento dos ermitões foi afetado somente pelo sombreamento. Entretanto, uma interação entre ambos os estressores foi observada para o odor de gastrópodes, causando a redução do deslocamento. Este estudo mostra como impactos locais podem amplificar efeitos de mudanças ambientais globais em populações de crustáceos do entremarés. / Multiple stressors due to anthropogenic activities may cause combined impacts in marine organisms. Effects of ocean acidification associated with other anthropogenic impacts are poorly understood, especially in coastal regions. In these areas, shading caused by infrastructure development, such as harbor construction, may potentially interact with CO2-induced pH reduction and affect invertebrate populations. Here we evaluated reduced pH and shading effects on mortality, growth, calcification and displacement behavior to live predator (danger signal) and dead gastropod (resource availability signal) odors using juveniles of the hermit crab Pagurus criniticornis collected in Araçá Bay (São Paulo state, SE Brazil). After a 98 days experiment period, both stressors had a significant interaction on mortality and an additive effect on total growth. No difference in calcification was recorded among treatments, indicating that individuals were able to maintain calcification under reduced pH. When exposed to odor of live predators, crabs\' responses were affected only by shading. However, an interactive effect between both stressors was observed in response to gastropod odor, leading to reduced displacement behavior. This study shows how local disturbance impacts may enhance effects of global environmental changes on intertidal crustacean populations.

This thesis aimed to understand the mechanisms underlying within-host interactions among coinfecting parasites in wild rodents, how they are affected by the host immune response, and how they contribute to shape disease dynamics in nature. Coinfection is ubiquitous in human, domestic and wild animal populations, and can consist of both microparasites (viruses, bacteria and protozoa) and macroparasites (parasitic helminths). Moreover, coinfecting parasites can interact with each other in a number of ways (positive or negative, direct or indirect), which affects disease severity and progression, parasite transmission, the response of target and non-target parasites to treatment and, ultimately, the epidemiology of each coinfecting parasite species. While previous work on laboratory animals has generated detailed knowledge of the cellular components of the host immune response involved during coinfection, we still mostly lack a conceptual understanding of the role of the host immune response in mediating within-host interactions in nature. I used a known within-host interaction between two important intestinal parasites (the nematode Heligmosomoides polygyrus and the protozoan Eimeria hungaryensis) of wild wood mice (Apodemus sylvaticus) to study the underlying causes and consequences of this interaction for both parasite dynamics and host health. I first investigated if specific and total antibody levels can explain natural burdens and infection of H. polygyrus and Eimeria spp. in the context of other parasites and variation in host demography in a cross-sectional field study. I found that H. polygyrus-specific IgG1 and total faecal IgA were the strongest predictors of both H. polygyrus infection and burden and Eimeria spp. infection. Further, Eimeria spp. infection was associated with lower antibody levels, suggesting an interaction between Eimeria spp. and anti-helminth immunity. Next, I tested the causative relationship between antibody levels and parasite infection. Over the course of a longitudinal anthelmintic treatment study in the field, I measured infection and burden of both target and non-target parasites, as wells as specific and general antibody levels. I found that treatment successfully reduced H. polygyrus burden, wild led to a change in both antibody levels and E. hungaryensis dynamics. Further, H. polygyrus-specific IgG1 levels were predicted by pre-treatment H. polygyrus burden, suggesting that helminth infection induces antibody production, rather than vice versa. Following from this, I explored if treatment of single or multiple parasite groups (helminths, coccidia or both) had an effect on host survival. I used data from a longitudinal field study spanning an entire season of A. sylvaticus (April-December), where animals were given either Ivermectin (anthelmintic), Vecoxan (anti-coccidial), a mix of both drugs or water every fortnight. Ivermectin treatment led to a consistent reduction in H. polygyrus prevalence and burden, as well as a steady increase in E. hungaryensis prevalence, whereas Vecoxan treatment failed to show any effect on either target or non-target parasites. Interestingly, anthelmintic treatment led to a reduction in survival at intermediate H. polygyrus burdens, suggesting that anti-parasite treatments might not always be beneficial for the host. By bringing this wild coinfection system into the lab, I examined if the interaction between H. polygyrus and E. hungaryensis could be re-created under controlled laboratory condition, and if the lack of environmental variation had an effect on parasite and/or antibody dynamics. I found that coinfection led to a delay in H. polygyrus expulsion, and decreased E. hungaryensis shedding during chronic helminth infection. However, coinfection did not affect antibody dynamics. This not only demonstrated that the interaction between the two parasites was reciprocal, but also showed that coinfection can significantly affect parasite transmission dynamics. In an ongoing bioinformatic analysis, I investigated the level of genetic diversity in wild Eimeria spp. populations in order to uncover the mechanism underlying a common lack of protective immunity towards Eimeria spp. infections in wild and domestic animal populations. I found that there were multiple genetically distinct strains circulating within all populations tested, but homologous re-infection was not less likely than heterologous reinfection. This suggests that the lack of protective immunity in wild Eimeria spp. Populations cannot solely be explained by high levels of genetic diversity. This thesis provides several important insights into the mechanisms underlying parasite within-host interactions. Importantly, it highlights that, whilst host immunity plays a crucial role in determining the outcome of coinfection, other factors such as host demography have to be taken into account in order to understand the interplay between immunity and coinfection. I further show that anti-parasite treatments in the wild can be successful, but the benefits of such treatments can be context dependent. More broadly, my findings can have important implications for the planning and evaluation of treatment programs targeted at both single and coinfected animals and humans in their natural environment.

Why is it that some athletes are able to withstand the pressures of competitive sport and attain peak performances, whereas others succumb to the demands and under-perform? It is the study of psychological resilience that aims to address this question. To significantly advance psychologists' knowledge and understanding of this area, there exists an urgent need to develop a sport-specific measure of resilience (Fletcher & Sarkar, 2012; Galli & Vealey, 2008; Gucciardi, Jackson, Coulter, & Mallett, 2011). The purpose of this thesis, therefore, is to investigate the assessment of psychological resilience in sport performers. To this end, the thesis is split into five chapters. Chapter one reviews and critiques the various definitions, concepts, and theories of resilience, and provides an overview of the research that has specifically examined psychological resilience in sport performers. Chapter two reviews psychometric issues in resilience research and its implications for sport psychology (part one), and discusses psychological resilience in sport performers via a review of the stressors athletes encounter and the protective factors that help them withstand these demands (part two). Drawing on these reviews of resilience in sport, Chapter three (studies one-three) describes the development and validation of the Sport Resilience Scale (SRS). More specifically, Study 1 explores the content validity of a pool of items designed to reflect psychological resilience in athletes, Study 2 examines the factorial structure of the SRS using exploratory factor analysis, and Study 3 tests the factorial structure of the SRS via confirmatory factor analysis, investigates whether the components of the measurement model are invariant across different groups, and examines the relationship between the SRS and other relevant concepts. Using the SRS, and based on Fletcher and Sarkar's (2012) grounded theory of psychological resilience, Chapter four (studies 4 and 5) investigates resilience in sport performers via an examination of moderation and mediation hypotheses. Specifically, Study 4 tests whether the association between the stressors athletes encounter and athletes' positive adaptation is moderated by the protective factors that athletes possess and Study 5 tests whether the association between the stressors athletes encounter and athletes' positive adaptation is mediated by their cognitive appraisal processes. Lastly, Chapter five offers a summary, discussion, and conclusion of the thesis. Overall, the research reported in this thesis has developed the first valid and reliable measure of psychological resilience in sport performers and has provided quantitative support for Fletcher and Sarkar's (2012) theoretical model of sport resilience by illustrating the moderating role of protective factors and the mediating role of cognitive appraisal.

abstract: Research on self-regulatory variables like mindfulness and effortful control proposes strong links with physical and mental health outcomes across the lifespan, from childhood and adolescence to adulthood and old age. One pathway by which self-regulation may confer health benefits is through individual differences in reports of and emotional responses to daily negative and positive events. Mindfulness is broadly defined as non-reactivity to inner experiences, while effortful control is broadly defined as attentional and behavioral regulation. Mindfulness and effortful control have both been conceptualized to exert their beneficial effects on development through their influence on exposure/engagement and emotional reactivity/responsiveness to both negative and positive events, yet few empirical studies have tested this claim using daily-diary designs, a research methodology that permits for examining this process. With a sample of community-dwelling adults (n=191), this thesis examined whether dispositional mindfulness (i.e., non-reactivity of inner experience) and effortful control (i.e., attention and behavioral regulation) modulate reports of and affective reactivity/responsiveness to daily negative and positive events across 30 days. Results showed that mindfulness and effortful control were each associated with reduced exposure to daily stressors but not positive events. They also showed that mindfulness and effortful control, respectively, predicted smaller decreases in negative affect and smaller increases in positive affect on days that positive events occurred. Overall, these findings offer insight into how these self-regulatory factors operate in the context of middle-aged adults’ everyday life. / Dissertation/Thesis / Masters Thesis Psychology 2018

The passage of the Individuals with Disabilities Act increased the need for special education teachers, but a shortage of qualified teachers currently exists. The high number of special education teachers who are making the choice to leave special education contributes to this shortage. It is widely accepted that stressors related to the profession impact the high attrition rate. One of the highest rates of attrition is found in self-contained Comprehensive Development Classes (CDC) where teachers provide highly individualized special education services in self-contained settings, often for the majority of the studentÆs day. The purpose of this study was to identify significant stressors experienced by teachers working in CDCs and their effects on teacher attrition from those programs. In this phenomenological study the guided interview approach was used to identify the specific stressors, methods of stressor identification, intensity of specific stressors, long- and short-term effects, possible outcomes related to identified stressors, and techniques used to relieve the effects of the stressors. Interviews were conducted with current and past CDC teachers, an assistant from each classroom, building administrators, and any support persons identified by the teachers. Information was also gathered from school and classroom records. The findings of this study identified specific stressors, sources of the stressors, effects on the teachers, and related information. The findings support that there is a relationship between stressors and the high rate of CDC teacher attrition for both experienced and novice teachers. Recommendations for practice related to the identified stressors include those made directly by the participants as possible methods of stressor alleviation that could result in a positive impact on teacher attrition.

Taxpayer dollars can be used more efficiently by land management agencies to monitor streams if agency-wide monitoring protocols are adopted. To address this issue, the Bureau of Land Management (BLM) developed the National Aquatic Monitoring Framework (NAMF) to implement standardized assessments of stream condition and trend in the Western United States. As one of the first applications of the NAMFI sought to develop and apply an analytical framework to determine the biological condition of streams, extent of in stream stressors and their impact on biological condition, and anthropogenic sources of stressors in Northeast California and Northwest Nevada over three years at a cost of $80,000. I measured biological, chemical, and physical attributes to determine the condition of stream sat 70 spatially distributed random locations. I found 45% of BLM stream km in the study area have degraded biology, 68% have excessive total nitrogen (TN), 43% have canopy cover below expected conditions, and 37% have excessive total phosphorus (TP). Excessive TN and TP and degraded riparian complexity (RC) were most strongly related to degraded biological conditions. The occurrence of excess TN and TP was most associated with livestock grazing. RC was identified as a stressor, but was not associated with land uses. This study provides an example of the data and analytical approach needed to help the BLM adaptively manage streams and rivers in compliance with federal regulations while efficiently using taxpayer dollars.

The primary objective of this research study was to examine employment and housing problems (stemming from the 2007-2009 Recession) and to see if there was a correlation between those problems and marital satisfaction and/or the perceived likelihood of future separation or divorce. A second purpose for this study was to see if feelings of financial stress (economic pressure) were mainly responsible for the projected drops in marital satisfaction or increases with divorce proneness. A final purpose for this study was to understand how other factors might additionally influence the relationships between recession-related employment problems and housing problems and the marital outcome variables. These factors included gender, race/ethnicity, socioeconomic status, and existing debt load. This study found that housing-related financial problems were associated with both lower marital satisfaction and a higher perceived likelihood of future separation or divorce. The economic pressure variable provided additional understanding regarding why couples with housing-related financial problems were more likely to have less desirable marital outcomes. Likewise, gender, race/ethnicity, socioeconomic status, and existing debt load also provided some modification of the existing relationships between housing-related financial problems and marital satisfaction and divorce proneness. However, this study did not find an association between employment-related financial problems and marital satisfaction or the perceived likelihood of future separation or divorce.

Recent scholarly efforts have sought to examine the cumulative impact of deleterious adverse childhood exposures on various mental health outcomes. Lifetime prevalence rates for depressive disorders are approximately 20% among adolescents. Depression is ranked as the leading cause for disability and fourth leading contributor to the global burden of disease in the world. The purpose of this study was to determine the cumulative impact of adolescent adverse experiences on outcomes of depression, suicide ideation, and overall mental distress in a cohort of 125 adolescent girls receiving public assistance. The adverse exposures studied were personal victimization, household dysfunction, and community violence exposures. Across the three categories of exposures, adolescents reported that community exposures were the highest 92.8%, followed by household dysfunction 89.6 %, and lastly, personal victimization 80%. Over 40% reported experiencing more than seven adverse exposures. There was a doubling in the incidence of depression by the fourth year, and an almost ten percent increase in mental distress by the fourth year. Evidence of a significant direct association was found for those experiencing victimization with depression and suicide ideation. The total Adolescent Adverse Exposures (AAE) score was positively correlated with the CES-D scores in the last three years of the study, however not with suicide ideation. The cumulative impact or 'dose-response' relationship of such exposures on depression, suicide ideation, or change over time was not found. In contradiction with general beliefs and existing literature, a significant negative association was found with depression and having a parent incarcerated or experiencing the divorce of parents. This finding suggests given the homogeneity of this population, experiencing both poverty and high levels of exposure to victimization, that having an incarcerated parent or parental divorce may be potentially protective mitigating the stressful experiences of continued victimization. The results of this study offer evidence of high prevalence rates of adversity occurring in the lives of these already at risk adolescents. A call for efforts to reduce community violence and personal victimization in the context of poverty are needed to prevent the growing rates of depression and suicide ideation for these fragile families and adolescence.

This research comprised of three studies designed to investigate the coping strategies utilised by high and low performing university students with non-academic stressors. Coping research has frequently focused on single stressors providing a distorted picture of coping. Utilising a combination of quantitative and qualitative methodologies, this research provides new insights into the dynamic and multi-dimensional nature of coping with long-term, multiple stressors. It extends our understanding of coping beyond traditionally individualistic conceptualisations where active coping is valued over prosocial relationship-focused coping. Conceptualisations of social support is broadened to view it in more complex interactional terms. In Study 1, 521 university students were surveyed using a standardised coping inventory, the Ways of Coping Checklist revised. Several demographic groups were identified as at academic risk. Having good health, along with the high use Social Support and Problem Solving and the low use of Self Blame strategies all predicted high GPA. Study 2 involved a content analysis of 179 Exclusion Appeal letters submitted by excluded students. When confronted with multiple stressors, poor performing students compartmentalised or amplified multiple stressors which resulted in patterns of reactive problem-focused or emotion-focused coping. Passive and uni-directional approaches to social support resulted in the depletion of such resources. Study 3 investigated adaptive coping patterns using an open-ended questionnaire and a semi-structured interview with twenty high performing students. High performers viewed multiple stressors as inter-related, which is termed cross situational appraisal and displayed a versatile coping pattern across stressors termed cross situational versatility. Proactive and prosocial coping are critical for the acquisition and maintenance of social support over a long-term period. Implications of these research findings for Student Services staff are discussed. / Doctor of Philosophy (PhD)

Thesis (M.A. (Industrial Psychology))--North-West University, Potchefstroom Campus, 2007.