Recent Submissions

  • Flood Survival Strategies of Overwintering Snakes

    Yagi, Anne .R.; Department of Biological Sciences
    This thesis investigates snake flood survival during hibernation and how anthropogenic habitat alteration and climate variability may affect habitat quality and overwintering survival. Chapter one reviews the current understanding of ecophysiology of hibernation in snakes. In chapter two, I introduce a winter habitat model of a subterranean space that remains flood and frost-free, referred to as the “life zone,” where snakes survive winter. I analyzed 11- winters of hibernation habitat data and 18-yrs of population mark-recapture data to assess the effects of the first flood event on an endangered Massasauga population. Following the flood event, snake observations declined despite hundreds of hours of search-effort. At the population level this was evidence of poor winter survival and recruitment post flood. The direct cause of mortality was not determined but poor winter survival in areas with a depleted life zone was statistically supported. In the third chapter, I measured the metabolic rate (M ̇_(O_2 )) at 5°C for three snake species that inhabit my study area. I varied water level conditions and measured activity and dive behaviours continuously during experiments. I found differences between species in their resting metabolic rate, which I attributed to body size differences. I confirmed, cutaneous respiration occurs at a low rate and was significantly upregulated during a forced dive (flood event). Therefore, there is an intrinsic physiological response to a flood event in neonatal snakes. However, post-flood recovery indicated a greater oxygen demand after the short-forced dive. An oxygen debt was incurred during a short-forced dive under normoxic conditions. My conclusions are, 1) hibernation habitat (i.e., life zone) must include a non-freezing, non-flooding aerobic space throughout winter to maintain snake survival. 2) cutaneous respiration is a short-term flood survival strategy. I found no support for a complete aquatic hibernation strategy 3) the energy costs of a full-dive is additive to the recovery energetic costs of a flood event. A neonatal snake wintering energy budget is proposed, and winter mortality conservation issues are discussed in chapter 4.
  • Effects of Sensory Processing Patterns on Inhibitory Control as a Function of ADHD-traits and Trait Anxiety

    Hare, Carolynn; Department of Child and Youth Studies
    Anxiety and ADHD (traits) have been shown to co-occur in both clinical and non-clinical populations. In addition, both anxiety and ADHD are independently associated with atypical sensory processing. However, there has been no previous research investigating their combined effects on cognitive functions. It is important to identify the nature of their interactions, because often the impact of multiple challenges in affective, social, and cognitive domains can be different from the impact of each individual condition. The dimensional models of mental disorders regard psychopathologies as continuous, interdependent conditions with symptoms existing as traits along a continuum in the population, rather than discrete diagnostic categories. Following this framework, the overarching goal of this event-related potential study is to investigate how individual differences in sensory processing patterns (SPPs), ADHD-traits and trait anxiety influence inhibitory control in 77 (final sample 60, ages 18-26) female and male non-clinical emerging-adults. It was expected that the effect of the SPPs on inhibitory control would depend on the level of ADHD-traits which are moderated by the level of trait anxiety. Two SPPs, low registration (LR) and sensory sensitivity (SS), ADHD-traits (inattention, impulsivity, hyperactivity) and trait anxiety were measured using self-report questionnaires. Inhibitory control was operationalized as the maximum peak amplitude of N2, a neurophysiological response frequently associated with inhibition paradigms. In this study, N2 response was elicited during a 22-minute computerized distractor Continuous Performance Task (d-AX-CPT) with three inhibitory conditions (Go Distractor, NoGo Distractor, NoGo No Distractor). The research hypotheses were tested in moderated moderation models separately for LR and SS as focal predictors, N2 amplitude as the outcome, and ADHD-traits and trait anxiety as primary and secondary moderators, respectively. The results revealed that the levels of impulsivity, but not hyperactivity and inattention, and trait anxiety together moderated the effects of SPPs on N2 amplitude in Go Distractor and NoGo Distractor Conditions. In general, the findings of this study (1) highlight the importance of understanding the complex relationships among comorbid patterns that are frequently observed in diagnostic groups, (2) add new information to the existing literature on the relationship between SPPs, ADHD and anxiety using a dimensional framework.
  • The hydrology of northern boreal lakes in the Taiga Shield and Plains, Northwest Territories and the importance of catchment characteristics in mediating responses to climate

    Viscek, Josef Anthony; Department of Earth Sciences
    Freshwater lakes are prominent features across northern boreal regions and are sensitive to changing climate conditions. This study, spanning the 2017-18 ice-free seasons, broadens our understanding of how variable climate and landscape conditions influence subarctic lake hydrology in the North Slave Region near Yellowknife, Northwest Territories (NT), Canada. We studied 20 lakes located within the Taiga Shield and Taiga Plains ecozones through an integrated approach, utilizing water isotope tracers (δ2H and δ18O), lake level changes, local meteorological conditions and remotely sensed catchment data. Lake water isotope data were obtained twice during the ice-free season (May and August) and evaporation/inflow (E/I) ratios were calculated to identify the relative importance of catchment hydrological controls. Hydrological data were compared to measured and modelled catchment characteristics, including relative lake/catchment size, slope, land cover and recent wildfire burn area. Overall, precipitation was a major driver of seasonal and interannual lake hydrological change, while evaporation was a major driver of summer water loss. Relative catchment size (lake area to catchment area (LA/CA)) was found to be an important driver of lake hydrology, however, this relationship is complicated by storage deficits associated with variable meteorological conditions. During wet conditions (e.g., freshet and periods of high rainfall), lakes with larger catchments (low LA/CA) had more positive water balances than lakes with high LA/CA. Under drier conditions, lake catchment size and associated fill-and-spill hydrological connectivity was reduced. Lake basins with high LA/CA (particularly those with shallower depth and greater surface area) were more prone to evaporative water loss. Lake hydrological conditions were less influenced by catchment land cover compositions, including burn area. Findings presented here highlight important drivers of lake water balances in subarctic boreal regions, which are sensitive to ongoing changes in climate. This study is part of a broader research project funded and supported by NWT Cumulative Impact Monitoring Program (CIMP), which is using a multi-proxy, paleo-ecological approach to determine long-term (i.e., 2,000 years) records of hydrology, drought, fire and water quality to inform future policy planning.
  • Comparing an Interdependent and Dependent Group Contingency to Increase Physical Activity in Students During Recess

    Asaro, Madeline; Center for Applied Disability Studies
    Physical activity is defined as any body movement that requires energy expenditure. It has important physiological, mental health, academic, and cognitive benefits for children and youth. Despite these advantages, a large proportion of this population does not meet the minimum recommended amount of physical activity. Recent studies have shown that the interdependent group contingency (IGC) and dependent group contingency (DGC) improve physical activity; however, no comparison of the effects of these group contingencies on physical activity has been conducted. We used a multielement within a concurrent multiple baseline across classes design to compare the effectiveness of these group contingencies to increase physical activity in two classes of grade 5 students. Both group contingencies increased physical activity in both classes, with the IGC producing slightly higher levels of physical activity than the DGC at the class-wide and individual levels of analyses. Conversely, side effect data suggest that participants in both classes preferred the DGC. Results are discussed within the context of treatment decisions and suggestions for future research.
  • Data mining using L-fuzzy concept analysis.

    Saha, Sajal; Department of Computer Science
    Association rules in data mining are implications between attributes of objects that hold in all instances of the given data. These rules are very useful to determine the properties of the data such as essential features of products that determine the purchase decisions of customers. Normally the data is given as binary (or crisp) tables relating objects with their attributes by yes-no entries. We propose a relational theory for generating attribute implications from many-valued contexts, i.e, where the relationship between objects and attributes is given by a range of degrees from no to yes. This degree is usually taken from a suitable lattice where the smallest element corresponds to the classical no and the greatest element corresponds to the classical yes. Previous related work handled many-valued contexts by transforming the context by scaling or by choosing a minimal degree of membership to a crisp (yes-no) context. Then the standard methods of formal concept analysis were applied to this crisp context. In our proposal, we will handle a many-valued context as is, i.e., without transforming it into a crisp one. The advantage of this approach is that we work with the original data without performing a transformation step which modifies the data in advance.
  • Comparing High-Probability Demands With and Without Food to Increase the Consumption of Healthy Food in Picky Eaters

    Tardi, Laura; Center for Applied Disability Studies
    The high-probability (high-p) instructional sequence is a nonintrusive antecedent-based intervention that involves the presentation of a series of high-p demands followed by one low- probability demand. To date, only nine studies have examined the effectiveness of the high-p sequence to treat food selectivity in children, and the findings have been mixed. In the current study, we used a multielement within a multiple baseline across food sets design to compare the effectiveness of two iterations of the high-p sequence to increase the consumption of healthy food in one picky eater. One iteration consisted of presenting three bites of a preferred food followed by a bite of the nonpreferred food and the other iteration consisted of presenting three bites of an empty spoon followed by a bite of the nonpreferred food. We found the high-p preferred food condition was more effective than the high-p empty spoon condition during one of two comparisons; however, we were unable to replicate the effectiveness of the high-p preferred food condition in the second comparison. Results are discussed within the context of the limitations and implications for future research.
  • Wearable activity monitors and goals: Perceptions on physical activity, attitudes and motivational outcomes

    Bell, Connor; Applied Health Sciences Program
    Evidence attesting to the benefits of wearable activity monitors for increasing PA has been reported (USDHHS, 2018). Goal setting is one behavior change technique that often accompanies wearable activity monitors and has been deemed an essential component to any health behavior change intervention (National Institute for Health and Care Excellence, 2014). Specific to PA behavior, goal setting has been deemed effective regardless of age, sex, and activity status (McEwan et al., 2016). Therefore, the purpose of this study was to determine if affective goals confer unique benefits on physical activity (PA), attitudes and behavioral regulations consistent with the Organismic Integration Theory (OIT; Ryan & Deci, 2017) among users of wearable activity monitors. Affective goals were compared with instrumental goals, step count and a no goal condition. Adopting a randomized experimental post-test only design, undergraduate students (N = 153) were assigned to one of eight conditions. Participants read a scenario then completed a battery of questionnaires housed on a secure online interface. Differences by condition were not found for short- or long-term PA or attitudes (p’s >.05). Differences were noted for extrinsic regulation (p = 0.025; ηp2 = .105). Results indicated that extrinsic regulation was higher in the no goal condition when compared to most other conditions. These findings imply that goal setting, regardless of type, may offset increases in extrinsic motivation associated with the use of wearable activity monitors. Users of wearable activity monitors looking to improve PA, positive attitudes and motivation associated with PA may benefit by utilizing goal setting in combination with other commonly used BCTs. A further investigation upon goal setting and users of wearable activity monitors is warranted.
  • Tone it Down or Tune it Out? The Focus of Instructor Cues on Body Image Outcomes during an Exercise Class in Older Adults

    Galway, Sarah; Applied Health Sciences Program
    In group exercise settings, many factors influence body image, including instructors and the motivational cues they use. The purpose of the present study was to examine the impact of appearance versus functionality-focused cues used by an instructor in an exercise class on state body image, enjoyment and intentions to return in older adults. One hundred and seven participants (26 males, 81 females, Mage = 69 years) took part in two visits. During visit one, participants completed demographic and trait body image questionnaires and had anthropometric measures taken. During visit two, participants were randomly assigned to an appearance or functionality-focused exercise class. In the appearance-focused class, the instructor’s cues emphasized the exercises as a way to alter the body’s appearance, whereas in the functionality- focused class, cues focused on exercise as a way to improve function and health. Participants completed state measures of body image immediately before and after participating in the exercise class. Following the exercise class participants also completed measures of enjoyment and intentions to return. Repeated-measures ANCOVAs were conducted for each state body image measure (body appreciation, functional appreciation, body dissatisfaction, body satisfaction with appearance and functionality, self-objectification, and social physique anxiety) controlling for appropriate demographic and trait body image variables. Participants assigned to the functionality-focused condition reported significantly greater decreases in body dissatisfaction [F (1,101) = 6.35, p = .013] compared to those in the appearance-focused condition, and regardless of condition, participants reported significant decreases in state self- objectification pre-to-post exercise [F (1,105) = 7.85, p = .006]. All other time by condition and time effects were non-significant (ps > .05). ANCOVAs to examine between-group differences on enjoyment and intentions to return showed no significant differences (ps > .05). It is possible that older adults, who place a greater focus on the health and functionality of their bodies, may be protected from negative effects of appearance-related commentary within group exercise settings (in contrast to young-women). Findings also suggest that exercise may be particularly beneficial for improving body dissatisfaction and self-objectification in populations across the lifespan. Future studies should continue to examine psychological outcomes of acute exercise in older adults.
  • Object Classification using L-Fuzzy Concept Analysis

    Addison, George Tsekpetse; Department of Computer Science
    Object classification and processing have become a coordinated piece of modern industrial manufacturing systems, generally utilized in a manual or computerized inspection process. Vagueness is a common issue related to object classification and analysis such as the ambiguity in input data, the overlapping boundaries among the classes or regions, and the indefiniteness in defining or extracting features and relations among them. The main purpose of this thesis is to construct, define, and implement an abstract algebraic framework for L-fuzzy relations to represent the uncertainties involved at every stage of the object classification. This is done to handle the proposed vagueness that is found in the process of object classification such as retaining information as much as possible from the original data for making decisions at the highest level making the ultimate output or result of the associated system with least uncertainty.
  • 'Sent down? Called up?': Exploring the roller coaster of loans and re-assignments in professional hockey

    McLaughlin, Bryan; Applied Health Sciences Program
    Athletes constantly face transitions in their sporting careers, which can influence the quality of their performance and well-being. The purpose of the study is to explore professional hockey players’ lived experiences with being called up and sent down in organizations. For example, an athlete can play in the National Hockey League (NHL) and is then sent down to their affiliated team in the American Hockey League (AHL) for a variety of reasons. The study utilized a phenomenological approach to understand athletes lived experiences with being called up and sent down, this allowed the researcher to move beyond brief descriptions toward understanding this specific transition athletes face. Semi-structured interviews were audio-recorded and transcribed verbatim, which occurred with six current hockey players (five current professional athletes and one competitive athlete). Data-analysis followed a two-phase process analysis to determine themes and patterns within each interview and then compared patterns across interviews to see what is common across interviews. The results were presented in three clusters such as the performance and well-being of an athlete, external influences on career, and interpretations of experiences. Further research is needed to explore the impact that loaning can have on an athlete and their well-being.
  • Parental Literacy Experiences: Relation to a Child's Reading Performance Across Cultures

    Banach, Nicole; Center for Applied Disability Studies
    Correlational studies have confirmed significant relationships between parents’ past reading experiences and involvement in children’s literacy at home and how this could be associated with their children’s reading outcomes and motivation. The current study examined parental self- reported literacy experiences, home literacy experiences, child reported motivation for reading and potential associations with children’s reading development across Hispanic, African American, Caucasian, and Chinese cultures. Participants were recruited from public schools in New Haven Connecticut, United States of American and one urban elementary school in China. In total 238 children and either of their parents participated in the study. Parents form both samples completed a personal information questionnaire while participating children completed a battery consisting of reading tasks and a reading motivation measure. Significant correlations for differences between cultural groups were identified. Overall, findings of this study suggest that parents’ reading experiences and culture-specific home literacy practices could influence children’s reading motivation and reading performance. To conclude, existing research and findings from the current study propose culture-specific literacy practices that may be adapted by other cultures to strengthen children’s reading development. Additional directions for future research were discussed.
  • Characterization of plant, leafhopper, and spider communities in perimeter plantings and vineyards in the Niagara region

    Hughes, Margaret Moira; Department of Biological Sciences
    Vineyards are large agroecosystems associated with high external inputs and intervention leading to local decreases in biodiversity. With trends towards sustainable agriculture, there is a push to maximize natural ecosystem functions through methods of on-farm diversification, such as perimeter plantings. Increased plant diversity has been found to increase the ability to exploit natural ecosystem functions such as pest management, through the bottom-up control of species richness displayed by increased plant species richness. The aim of this thesis was to investigate the effect of perimeter plantings on vineyard plant and invertebrate communities. I hypothesized that perimeter plantings would have greater plant diversity and habitat complexity than vineyard interiors. Perimeter plantings would also support increased assemblages of natural enemies with decreased pest populations when compared to the vineyards. Plant communities in the perimeter plantings and the vineyards were first surveyed using transects within the perimeters and perpendicular transects from the perimeters towards the interior of the vineyards. Invertebrate communities were also surveyed within the perimeter plantings and adjacent vineyards, focusing on leafhoppers and spiders. Seven commercially operating vineyards throughout the Niagara region were surveyed both within the perimeter planting and adjacent vineyard during the 2018-growing season. It was found that perimeter plantings not only had increased plant species richness and functional diversity, but the species and functional composition within the perimeters differed from vineyard interiors. This indicated that perimeter plantings did not increase weed pressure but allowed for increased habitat complexity adjacent to the vineyards. Leafhoppers showed significantly higher abundance in vineyard interiors than perimeter plantings, and as distance from perimeter planting increased, leafhopper abundances also increased. Spiders were more abundant in perimeter plantings, decreasing in abundance with distance from perimeter. Overall, the results suggest that perimeter plantings have the ability to support biological pest control, while not increasing both weed or pest pressure observed within vineyards.
  • Alpha suppression as a neural marker of task demands in voluntary vs involuntary retrieval in older and younger adults

    Henderson, Sarah Elizabeth; Department of Psychology
    Voluntary episodic memory relies on intentionally controlled retrieval, while involuntary episodic memory comes to mind automatically. Consistent with findings of reduced cognitive control with age, recent work suggests that voluntary memory declines with age while involuntary memory is relatively preserved. However, the neurophysiology underlying these age differences has yet to be established. The current study used EEG to test 31 young and 35 older adults during voluntary vs. involuntary retrieval (manipulated between-subjects). Participants first encoded sounds, half of which were paired with pictures, the other half unpaired. EEG was then recorded as they listened to the sounds, with participants in the involuntary group performing a sound localization task, and those in the voluntary group additionally attempting to recall the associated pictures. Participants later retrospectively reported which sounds brought the paired picture to mind during the sound task. Older adults said they remembered as many pictures as young adults, but their objective memory was lower on a final cued recall test. For the EEG analysis, older adults showed greater alpha event-related desynchronization (ERD; a neural marker of memory reactivation) for paired than unpaired sounds at occipital sites, possibly reflecting visual reactivation of the associated pictures. Young adults did not show memory-related alpha ERD effects. However, young adults did show greater alpha ERD during voluntary than involuntary retrieval at frontal and occipital sites, while older adults showed pronounced alpha ERD (indicative of effortful retrieval) regardless of condition. These data suggest that alpha ERD can be used as a neural marker of memory in older adults; however, a more naturalistic paradigm may be required to study true involuntary memory with age.
  • Girl Bloggers: Posthumanism and Girls' Online Activism

    Sheppard, Lindsay C.; Department of Child and Youth Studies
    In this thesis, I explore the complexity of young women’s online activism through analysis of five blogs and online interviews with three of the bloggers. Informed by Karen Barad’s approach to posthumanism, I examine how specific material-discursive entanglements around girlhood, youth and activism co-constitute meanings and experiences of activism and activist subjectivities. Four themes and various subthemes emerged from my analysis. First, the blogging process is complex, involving various entangled materialities (e.g. art, wifi, laptops, notebooks), space, time and discourses around what makes a “good” blogger. Second, the format and content of the blogs, as well as the bloggers’ narratives, illustrate tensions and similarities between mobilizing an online gendered activist subjectivity and social media influencer (i.e. micro-celebrity) subjectivity within a broader neoliberal culture focused on entrepreneurship and individual success. The young women’s comments highlight the ways that neoliberal girl power narratives underpin expectations of activist bloggers. Third, young women engaged in activism on their blogs and on other connected social media accounts, where they represented activism through individualized approaches, and more rarely, as involving broader systemic critique. The young women conceptualized activism broadly, although their discussions of activist blogging and self-identification as activists were messy and contextual. The final theme considers how intersecting social positionings (e.g. gender, race, class, age, disability) shape access to and experiences with activist blogging. Overall, the aim of this project is to offer a rethinking of young women’s activism blogging that attends to the force of entangled material-discursive contexts.
  • The Relation Between Young Children's Memory and Metacognition

    Lavis, Lydia; Department of Psychology
    Prospective memory, the ability to remember to carry out future intentions (PM; Einstein & McDaniel, 1990) is a critical skill in children’s daily lives. Despite this, little is known about children’s awareness of their own PM ability and how this might be affected by the difficulty of a PM task. The current study sought to examine the effect of task difficulty on children’s predictions, postdictions, and actual PM performance. Four-to 6-year-old children (N = 132) completed an easy or difficult PM task and made predictions and postdictions before and after the task. Results showed that: (1) children’s PM increased with age and was worse in the difficult condition, (2) PM predictions and postdictions did not vary with age but PM postdictions were more accurate than PM predictions, and (3) PM postdictions were affected by difficulty of the PM task with children reporting having remembered to carry out their intention fewer times in the difficult compared to the easy condition. Overall, children’s PM postdictions were more accurate than their predictions, and difficulty of a PM task only affected children’s reflections (and not predictions) of their PM performance.
  • The Ethics of Categorization in Sport: An Analysis of the Possible Elimination of Under 19 Lightweight Rowing in Canada

    Giesbrecht, Jacob; Applied Health Sciences Program
    In 2017 a proposed rule change was made by a working group appointed by Rowing Canada Aviron to eliminate the U19 lightweight rowing category in Canada. While this proposal did not come to fruition, it did raise questions about the purpose and ethics of maintaining such a category. The purpose of this study was therefore to explore the perceptions of those closely involved with U19 lightweight rowing in Canada and the ethical considerations and ramifications of a possible ban on this category. Ten interviews were conducted with coaches and administrators closely associated with the topic to ascertain individual and group perceptions of this proposal. Based on Charles Taylor’s hermeneutic phenomenology, this study uncovered and evaluated the ethical implications and validity of the possible elimination of U19 rowing in Canada and provided a commentary on categorization in sport more broadly. The results of the interviews revealed six main emergent themes that included concepts of; natural lightweights, opportunity and fairness, health and harm reduction, education, coaching abuse or neglect, and accountability. After analyzing the perceptions of participants and applying an ethical analysis to the issue, a possible ban of U19 lightweight rowing in Canada was deemed ethically unjustifiable.
  • Exploring the Impact of a Teacher Education Program on the Mathematical Anxieties of Elementary Pre-Service Teachers

    Gannon, Sarah; Department of Graduate and Undergraduate Studies in Education
    Mathematics education in Ontario has been a topic of significant focus in recent years. One concern is the lack of strong elementary mathematics teachers, in part due to the high levels of mathematics anxiety amongst this population (Gresham, 2007; Novak & Tassell, 2017). This study investigated the impact of a teacher education program on elementary pre-service teachers’ mathematical anxieties. The study examined the main components of a consecutive teacher education program, namely mathematics methods courses and field experiences, their interrelationships, and their connections with pre-service teachers’ background experiences. This explanatory sequential mixed methods approach emphasized qualitative methods (i.e., quan → QUAL) and involved two distinct phases. In Phase 1, quantitative questionnaire data were collected from the nine elementary pre-service teacher participants and analyzed using descriptive statistics. These results were then connected to the individual interview protocols employed in Phase 2 to collect qualitative data, which were analyzed thematically using the constant comparative method to uncover six themes: (a) prior experiences with mathematics, (b) anxieties towards mathematics, (c) the influence of mathematics methods courses on mathematical anxieties, (d) the influence of field experiences on mathematical anxieties, (e) the synthesis of mathematics methods courses and field experiences, and (f) anticipated future mathematics teaching style. This study’s results address gaps in the existing literature and highlight the key impacts of teacher education programs on pre-service teachers’ state and trait mathematical anxieties. Suggestions are provided for the practice of teacher educators, faculty administrators, and mentor teachers, as well as implications for theory and recommendations for future research.
  • Implicit associative memory remains intact with age and extends to target-distractor pairs

    Davis, Emily; Department of Psychology
    Past research has shown that older adults’ reduced inhibitory control causes them to hyper-bind, or form erroneous associations between task-relevant and -irrelevant information. In the current study, we aimed to extend hyper-binding to a novel, implicit memory paradigm. In two experiments, participants viewed pictures of objects superimposed with text and their task was to make speeded categorization judgments about the objects. The encoding phase contained three blocks that varied the potential for binding: no-binding, some-binding, and full-binding. During the no/some-binding blocks, participants decided if the pictured object alone could fit inside a common desk drawer while ignoring the superimposed text. In the no-binding block, the text was a nonword; in the some-binding block, it was an object word. During the full-binding block, participants attended to both the picture and word and decided if both items could fit inside a drawer together. After a delay, participants completed the test phase during which they viewed intact and rearranged pairs from the three encoding blocks and decided if both items could fit in a drawer together. In both experiments, older adults responded faster to intact than rearranged pairs from both the some- and full-binding blocks, suggesting that they had learned both target-target and target-distractor pairs. Young adults showed no difference in RTs to pairs from either block. These findings suggest that the binding mechanism itself is spared with age; what declines instead is inhibitory control, which serves to limit attention, and ergo binding, to task-relevant information.
  • The Physiological and Behavioural Consequences of Reduced Scalation in Captive-bred Phenotypes of the Bearded Dragon (Pogona vitticeps Ahl 1926)

    Sakich, Nicholas; Department of Biological Sciences
    Lepidosaurs as a group are known for their tough, scaled integument and low rates of evaporative water loss. Whether or not there is a causal relationship between the two has been a contentious issue. There also remains the question of whether the lepidosaur scale forms a barrier to ultraviolet (UV) light. Thirdly, there is evidence to suggest that rate of evaporative water loss influences behavioural thermoregulation in lepidosaurs. Lepidosaurs with higher rates of evaporative water loss should be expected to choose cooler temperatures than lepidosaurs with lower rates of evaporative water loss in order to reduce water loss. To investigate these ideas, I used three captive-occurring phenotypes of the bearded dragon (Pogona vitticeps Ahl 1926): Wild Type, animals exhibiting scales of reduced prominence (“Leatherback”), and scaleless animals (“Silkback”). I a priori expected that Silkbacks would have the highest rates of evaporative water loss, the lowest thermal preferences, and the lowest UV light intensity preferences. By the same token, I expected Wild Types to be at the opposite end of the spectrum from Silkbacks for each of these measurements, and I expected Leatherbacks to be intermediate between the two. I used respirometry to measure the animals’ rates of evaporative water loss, a thermal gradient to measure their thermal preferences, and a UV light intensity gradient to measure their UV light intensity preferences. Silkbacks on average lost water at about twice the rate that Wild Types did, with Leatherbacks being intermediate in their water loss rates. The three phenotypes did not visibly differ in their thermal preference. Silkbacks had lower UV light intensity preferences than either Leatherbacks or Wild Types. These results suggest that the lepidosaur scale is indeed a barrier to evaporative water loss and suggest that it is also a barrier to UV light. However, the lack of obvious difference in thermal preference suggests that thermal preference in bearded dragons is not plastic enough to respond to a phenotype that increases the animal’s rate of evaporative water loss. In addition to answering basic questions about lepidosaur biology, my data have relevance to the fields of animal welfare and conservation.
  • A Functional Programming Language with Patterns and Copatterns

    Alkhulaif, Shams A.; Department of Computer Science
    Since the emergence of coinductive data types in functional programming languages, various languages such as Haskell and Coq tried different ways in dealing with them. Yet, none of them dealt with coinductive data types properly. In lazy languages such as Haskell, both inductive data types and coinductive data types are gathered and mixed in one list. Moreover, some languages such as Coq used the same constructors that are used for inductive data types as a tool to tackle coinductive data types, and while other languages such as Haskell did use destructors, they did not use them properly. Coinductive data types behave differently than inductive data types and therefore, it is more appropriate to deal with them differently. In this thesis, we propose a new functional programming language where coinductive data types are dealt with in a dual approach in which coinductive data types are defined by observation and inductive data types are defined by constructors. This approach is more appropriate in dealing with coinductive data types whose importance comes from their role in creating a safer and more sophisticated software.

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