Closely related species at the same trophic level are often considered to be ecologically equivalent. However, it is clear that individuals species can have unique functional roles that drive community and ecosystem processes. In this study we examine the growth responses of two Neotropical hylid tadpole species, Agalychnis callidryas and Dendropsophus ebraccatus, to intraspecific and interspecific competition. We also look at density-dependent effects of each on phytoplankton, periphyton and zooplankton, as well as their responses to a caged dragonfly predator through ontogeny. Intraspecific competition affected both species similarly, and their effects on resources were qualitatively similar but quantitatively different. Predators affected resource levels and interspecific competition. Predator effects on tadpole size varied in both magnitude and direction through ontogeny for both species. This study shows that closely related species at the same trophic level can have different ecological roles and that tadpoles are more functionally unique than previously thought.

Master of Science / Department of Biology / Theodore J. Morgan / The organismal response to temperature represents one of the most ubiquitous processes that occur in the natural world, and this response is critical for survival in most habitats. Increased attention should be focused on how organisms cope with temperature extremes, either through adaptation, plasticity, or a combination of both, as climate models predict increased variations in temperature accompanied by novel thermal extremes. Drosophila melanogaster is an excellent resource for answering questions pertaining to how organisms persist in environmental extremes because they originated in central tropical Africa and have since colonized nearly the entire globe, exposing them to many novel thermal stressors. In this work I elucidated regions of the genome contributing to phenotypic variation in cold tolerance and thermal plasticity. A quantitative trait locus (QTL) approach was used, which involved phenotyping roughly 400 recombinant inbred lines (RILs) of D. melanogaster from the Drosophila Synthetic Population Resource (DSPR). The DSPR captures genetic variation from around the globe, allowing for precision mapping of cold tolerance and thermal plasticity QTL, while simultaneously determining the frequency of the QTL alleles. Upon development at both 18°C and 25°C, RILS were measured for a common cold tolerance metric, chill-coma recovery time (CCR), and a plasticity value was derived as the change in CCR between environments. Analysis of variance revealed significant effects of sex, line (RIL), treatment (temperature), and line by treatment interaction (GxE). Mapped QTL for chill-coma recovery time at 18°C and 25°C spanned the same regions as several studies previously reported, validating the automated phenotyping method used and the mapping power of the DSPR. QTL between CCR at 18°C and 25°C overlapped significantly, and QTL for thermal plasticity shared the similar regions as QTL for CCR, but also exhibited two non-overlapping QTL on the left arm of the third chromosome. This study demonstrated the tremendous amount of variation present in cold tolerance phenotypes and identified candidate regions of the genome that contribute to thermal plasticity and require further investigation.

The purpose of this study is to examine if testosterone shows reactivity to skydiving and to examine whether the testosterone level and reactivity was associated with sex and sensation seeking trait of the participants. Testosterone is an important steroid hormone which has several biological and socio-behavioral effects on people and is also present in disproportionate amounts in males and females; thus, it is important to explore how this hormone acts in different sex. Furthermore, exploring the relationship between sensation-seeking and testosterone could provide insight into the relation between psychological factor and hormonal response in humans. Forty-four people were recruited to participate in the study. The sample comprised of 73% males (N=32) and 27% females (N=12) with a mean age of 24 years (SD = 4.6) and an age range of 18 to 49. The participants volunteered to jump out of an airplane and give saliva samples at different time points during that day and during another day (basal levels). This study found that testosterone shows reactivity in response to skydiving, where the peak levels in males were higher than in females. It also found that people who scored higher in experience-seeking scores had higher testosterone level at jump than people who scored lower. Furthermore, it also revealed that people who scored higher in intension-seeking scores showed more reactivity in terms of testosterone i.e. the rise was steeper in these people. In summary, we see that psychological factors and sex predicted reactivity and peak level of testosterone after skydiving.

The aim of this study is to analyse and describe how resilient adolescent learners in a township school cope with school violence in order to develop and recommend a model to promote resilience in coping with school violence. As basis for this study violence is described and explained in the theoretical framework of the ecosystemic theory, as well as the social learning and cognitive behavioural theories. Based on these theories violence is discussed as a reaction and as an action that occurs through reciprocal interaction between the systems and the social environment. Through this interaction adolescent learners could be exposed to individual, family, community and school related risk factors and external barriers, which could have psychological impact, and could lead to a path of violence and self-destruction. Thus, the view of the study is that some learners have the ability and skills to cope with school violence, whilst others are not capable of coping with school violence. However, both groups could learn coping skills. This study wishes to further show that in order for adolescent learners in a township school to cope with school violence certain intrapersonal characteristics and social interpersonal skills of resilience, as well as external protective factors should be present. Therefore, background to research into the theories of resilience and coping based on Salutogenesis is provided. Salutogenesis stresses the importance of how well-being (resilience and coping) is created and maintained. The specific research design selected for this study is a case study and is qualitative, explorative and descriptive in nature. This research design is also emergent and is logically constructed according to qualitative research methods to ensure credibility and validity if the study. The research design further provides clear direction for the way in which the fieldwork is undertaken. A two-pronged approach was followed with the data collection. First, a pilot study was done for refinement of questions and data collection formats as well as for understanding the realities of the fieldwork and research process. Secondly, the data were collected from participants in three different phases, including gathering of background information of the school; obtaining views about school violence, resilience and coping; as well as collecting data from resilient adolescent learners about their violent experiences and how they coped with school violence. The process of analysis that was followed was to describe the protocol for all phases; to identify and describe the themes that emerged from the data of all phases; and to present a clear profile of each resilient adolescent learner. The results were presented within a narrative that should provide the reader with enough information to determine whether the findings of the study could possibly apply to other people or settings. The findings of the study revealed that many adolescent learners in the township school experienced direct incidences of violence either at school or in the community. The most common types of violence reported by the participants, are bullying, fighting, swearing, gangsterism, carrying of weapons, stabbing and gambling. Other contributory factors are racism and substance abuse. Reportedly, the nature of violence changed over the years because of efforts, mainly from the educators, to develop a workable discipline system. It was also found that there were learners at this school who coped with school violence because of intrapersonal characteristics of resilience, social interpersonal skills, and external factors. The intrapersonal characteristics of resilience are an appealing temperament; sense of coherence; internal locus of control; positive self-concept; being future directed, and belief in a Higher Being. The social interpersonal skills are communication skills, cognitive skills, and conflict resolution skills. The external factors are family support and social support. Based on these findings this thesis develops and recommends a systemic-based model to promote resilience in adolescent learners in coping with school violence in a township school. / Prof. R.E Swart

No description available.

The overall purpose of the present study is to contribute to a better understanding of the experiences of young homeless women residing at Covenant House New York, a youth shelter that provides crisis and long-term residential programs to young adults ages 18 – 21. The main objective was to identify past life events and their contributions to the development of positive traits and psychopathology among three groups. The participants were 162 homeless young women, including childfree women, young mothers enrolled at a transitional living Rights of Passage program (12-18 months), and young mothers in crisis enrolled in a 30-day Mother and Child Crisis program. Past life experiences were identified via the Effort to Outcome (ETO) online software database maintained by Covenant House New York. Rates of psychopathology were measured using the IIP (interpersonal problems), PHQ-9 (depression), GAD-7 (anxiety), PSS (parental stress) while rates of positive traits were measured using the SCS (self-compassion), SCBCS (compassion toward others), and PGIS (motivation to change). The results indicated that all participants, regardless of group affiliation, had similar life experiences, though childfree women were more likely to have a history of abandonment, physical abuse, and previous incidents of homelessness. Additionally, presence of abuse history was positively associated with development of psychopathology. As expected, history of sexual abuse was negatively associated with self-compassion, but it was positively associated with compassion toward others. Mothers at the Mother and Child Crisis program had greater rates of self-compassion than mothers at the Rights of Passage program, and childfree women were more likely than the mothers to be compassionate toward others. Mothers at the Mother and Child Crisis program were also more likely to be compassionate toward others than mothers at the Rights of Passage program. Childfree women, however, were more likely to be depressed than mothers at the Mother and Child Crisis program.

In three parts, this dissertation seeks to clarify constructs used in contemporary and emerging models of child resilience, examine the predictive capacity of these models, and delineate key steps towards improving and refining models useful to mental health and psychosocial support program and policy initiatives in humanitarian settings. Data collected for this research was part of an inter-agency evaluation of Child Friendly Spaces in Nepal following the 2015 earthquake. Findings from these studies call for future research directed towards the development of more rigorous and equitable indicators used to evaluate mental health and psychosocial support programs that allow for a longer tracing of healthy developmental trajectories for children affected by situations of extreme adversity.

Cognitive processes have been shown to be severely affected by exposure to combat and war. While the negative impact of war on cognitive performance is apparent through numerous soldier narratives, the scientific investigation of this phenomenon is limited. Furthermore, the moderating influence of an individual’s resilience and grit on cognitive functions following combat environments is unknown. Understanding this interaction is essential in further understanding individual cognitive performance. Because the psychological wounds inflicted by combat situations affect individuals’ mental health, studying how such environments influence cognitive processes and performance can improve the training of our soldiers. This dissertation focuses on assessing how combat-like environments influence an individual’s ability to effectively and efficiently reason, and further examines whether an individual’s grit and resilience affect deductive and inductive reasoning in stressful environments. Participants were recruited from a private US military academy. The study used a pretest-posttest mixed design to investigate possible cognitive decrements in individuals’ ability to reason following exposure to war-like environments simulated by immersive and non-immersive technologies. Dependent measures included both inductive and deductive reasoning (as measured by The Letter Sets Test and Overton’s (1990) version of the Wason Selection Task, respectively) by placing participants into the immersive or non-immersive conditions. Self-reported resilience and grit were tested for interaction effects to examine how an individual’s resilience and grit influences an individual’s ability to reason in war-like environments. These findings might give a richer understanding of the ways in which cognitive mechanisms are affected by stressful environments like combat.

Increases in the number of enlisted veterans transitioning from active duty to the civilian world have drawn attention to a need for research in terms of unemployment to examine how separated service members experience transition from their perspective. Fifteen separated enlisted veterans from four of the five military branches were selected and interviewed in this study. The focus was to understand better the complexities of reintegrating into the civilian workforce, as experienced by veterans from the enlisted military population. By using qualitative methodologies including exploratory interviews and a focus group, the findings revealed four major themes on how service members described their transition experience: (a) perception that military leadership does not provide adequate support when transitioning and the need to become more self-directed in one’s own learning; (b) belief that the military TAP class is helpful but needs major changes to truly be effective; (c) description of a battle buddy or a family member as a positive influence in helping with the transition process; and (d) experiencing significant challenges with civilian employers when transitioning out of the military. An analysis of the findings led the researcher to conclude that transitioning veterans must become self-directed in their learning in order to transition successfully. Moreover, because they are at varying levels of being self-directed when they transition, additional guidance is needed from military leadership, family, and other veterans for the purpose of their development. The analysis also yielded a principal recommendation for military leadership to advocate for quality training programs that are specified from the separated enlisted population for what resources they need to assist with transition to the civilian sector. Additional recommendations were presented to transitioning service members on the importance of managing their own success and believing in their abilities to be resilient, valuable members of the civilian community.

For failure experiences to be productive for future performance or learning, students must be both willing to persist in the face of failure, and effective in gleaning information from their errors. While there have been extensive advances in understanding the motivational dispositions that drive resilience and persistence in the face of failure, less has been done to investigate what strategies and learning behaviors students can undertake to make those failure experiences productive. This dissertation investigates what kinds of behaviors expert learners (in the form of graduate students) employ when encountering failure that predict future performance (Study 1), and whether such effective behaviors can be provoked in less sophisticated learners (in the form of high school students) that would subsequently lead to deeper learning (Study 2). Study 1 showed that experiencing and responding to failures in an educational electrical circuit puzzle game prior to formal instruction led to deeper learning, and that one particular strategy, “information-seeking and fixing”, was predictive of higher performance. This strategy was decomposed into three metacognitive components: error specification, where the subject made the realization that a knowledge gap or misunderstanding led to the failure; knowledge gap resolution, where the subject sought information to resolve the knowledge gap; and application, where subjects took their newly acquired information to fix their prior error. In Study 2, two types of prompts were added to the educational game: one that provoked students through these metacognitive steps of error specification, information seeking, and fixing, labelled the “Metacognitive Failure Response” (MFR) condition; and a second prompt that provoked students to make a global judgment of knowing, labelled the “Global Awareness” (GA) condition. The results indicated that although there were no significant condition differences between the three groups (MFR, GA, and control condition where participants received no prompt at all), more time spent on the MFR prompt predicted deeper and more robust learning. In contrast, more time spent on the “Global Awareness” prompt did not predict deeper learning, suggesting that individual factors (such as conscientiousness) did not alone account for the benefits of time spent on the MFR prompt on learning. These results suggest that while MFR participants who carefully attended to the metacognitive prompts to specify the source of their errors and seek information experienced learning benefits, not all MFR participants sufficiently attended to the prompts enough to experience learning gains. Altogether, this body of research suggests that using this “error specification, info-seeking, fixing” strategy can be effective for making failure productive, but other instructional techniques beyond system-delivered prompts must be employed for full adoption of this metacognitive response to failure. Implications for teaching students to respond effectively to failure, for games in the classroom, and for design and engineering processes are discussed.