Matching Items (77)
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Traumatic brain injury (TBI) most frequently occurs in pediatric patients and remains a leading cause of childhood death and disability. Mild TBI (mTBI) accounts for 70-90% of all TBI cases, yet its neuropathophysiology is still poorly understood. While a single mTBI injury can lead to persistent deficits, repeat injuries

Traumatic brain injury (TBI) most frequently occurs in pediatric patients and remains a leading cause of childhood death and disability. Mild TBI (mTBI) accounts for 70-90% of all TBI cases, yet its neuropathophysiology is still poorly understood. While a single mTBI injury can lead to persistent deficits, repeat injuries increase the severity and duration of both acute symptoms and long term deficits. In this study, to model pediatric repetitive mTBI (rmTBI) we subjected unrestrained juvenile animals (post-natal day 20) to repeat weight drop impact. Animals were anesthetized and subjected to sham or rmTBI once per day for 5 days. At 14 days post injury (PID), magnetic resonance imaging (MRI) revealed that rmTBI animals displayed marked cortical atrophy and ventriculomegaly. Specifically, the thickness of the cortex was reduced up to 46% beneath and the ventricles increased up to 970% beneath the impact zone. Immunostaining with the neuron specific marker NeuN revealed an overall loss of neurons within the motor cortex but no change in neuronal density. Examination of intrinsic and synaptic properties of layer II/III pyramidal neurons revealed no significant difference between sham and rmTBI animals at rest or under convulsant challenge with the potassium channel blocker, 4-Aminophyridine. Overall, our findings indicate that the neuropathological changes reported after pediatric rmTBI can be effectively modeled by repeat weight drop in juvenile animals. Developing a better understanding of how rmTBI alters the pediatric brain may help improve patient care and direct "return to game" decision making in adolescents.
ContributorsGoddeyne, Corey (Author) / Anderson, Trent (Thesis advisor) / Smith, Brian (Committee member) / Kleim, Jeffrey (Committee member) / Arizona State University (Publisher)
Created2014
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The Maricopa County Heat Relief Network (HRN) is an ad-hoc partially self-organized network with some attributes of hierarchical coordination that forms each year to provide heat relief and hydration to residents in need by operating as cooling centers. These HRN organizations are a collection of non-profit, governmental and religious organizations.

The Maricopa County Heat Relief Network (HRN) is an ad-hoc partially self-organized network with some attributes of hierarchical coordination that forms each year to provide heat relief and hydration to residents in need by operating as cooling centers. These HRN organizations are a collection of non-profit, governmental and religious organizations. This dissertation looks at the HRN from a complexity governance perspective and engaged different parts of the network in interviews to learn more about their perspective in delivering heat relief. Further, participatory modeling with a prototype agent based model was done with the HRN coordinating agencies to look for emergent outcomes in the HRN system and learn from their perspective. Chapter one evaluates organizational theory and complexity with climate adaptation, hazard preparedness and resilience in the HRN. Chapter two presents results from interviews with HRN facility managers and evaluates their perspective on how they function to offer heat relief. Chapter three finds that the HRN is a good example of complexity governance when engaged through a participatory agent based modeling approach. Chapter four engages the HRN coordinators in participatory agent based modeling interviews to increase their systems level awareness, learn about their perspective on heat relief delivery, and how the system can be improved. Chapter five looks across the different levels of the HRN investigated, the facility managers and coordinators, for differences and similarities in perspectives. The research conducted in this dissertation shows different levels of systems awareness of the different parts of the HRN and how participatory modeling can be used to increase systems awareness. Results indicate that there was very little horizontal network connection between HRN facility managers and most of the interaction was vertically coordinated indicating opportunities for increased network communication in the future both horizontally and vertically if communication interventions were put in place.

ContributorsUebelherr, Joshua (Author) / Johnston, Erik W., 1977- (Thesis advisor) / Hondula, David M. (Committee member) / Mossberger, Karen (Committee member) / Gerber, Brian (Committee member) / Arizona State University (Publisher)
Created2017
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Food is an essential driver of animal behavior. For social organisms, the acquisition of food guides interactions with the environment and with group-mates. Studies have focused on how social individuals find and choose food sources, and share both food and information with group-mates. However, it is often not clear how

Food is an essential driver of animal behavior. For social organisms, the acquisition of food guides interactions with the environment and with group-mates. Studies have focused on how social individuals find and choose food sources, and share both food and information with group-mates. However, it is often not clear how experiences throughout an individual's life influence such interactions. The core question of this thesis is how individuals’ experience contributes to within-caste behavioral variation in a social group. I investigate the effects of individual history, including physical injury and food-related experience, on individuals' social food sharing behavior, responses to food-related stimuli, and the associated neural biogenic amine signaling pathways. I use the eusocial honey bee (Apis mellifera) system, one in which individuals exhibit a high degree of plasticity in responses to environmental stimuli and there is a richness of communicatory pathways for food-related information. Foraging exposes honey bees to aversive experiences such as predation, con-specific competition, and environmental toxins. I show that foraging experience changes individuals' response thresholds to sucrose, a main component of adults’ diets, depending on whether foraging conditions are benign or aversive. Bodily injury is demonstrated to reduce individuals' appetitive responses to new, potentially food-predictive odors. Aversive conditions also impact an individual's social food sharing behavior; mouth-to-mouse trophallaxis with particular groupmates is modulated by aversive foraging conditions both for foragers who directly experienced these conditions and non-foragers who were influenced via social contact with foragers. Although the mechanisms underlying these behavioral changes have yet to be resolved, my results implicate biogenic amine signaling pathways as a potential component. Serotonin and octopamine concentrations are shown to undergo long-term change due to distinct foraging experiences. My work serves to highlight the malleability of a social individual's food-related behavior, suggesting that environmental conditions shape how individuals respond to food and share information with group-mates. This thesis contributes to a deeper understanding of inter-individual variation in animal behavior.
ContributorsFinkelstein, Abigail (Author) / Amdam, Gro V (Thesis advisor) / Conrad, Cheryl (Committee member) / Smith, Brian (Committee member) / Neisewander, Janet (Committee member) / Bimonte-Nelson, Heather A. (Committee member) / Arizona State University (Publisher)
Created2017
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The goal of the present study was to investigate whether a rest period following the end of chronic stress would impact fear extinction. Past research has indicated that chronic stress leads to impairments in the learning and recall of fear conditioning extinction. Moreover, the effects of chronic stress

The goal of the present study was to investigate whether a rest period following the end of chronic stress would impact fear extinction. Past research has indicated that chronic stress leads to impairments in the learning and recall of fear conditioning extinction. Moreover, the effects of chronic stress can return to levels similar to controls when a post-stress “rest” period (i.e., undisturbed except for normal husbandry) is given prior to testing. Male rats underwent chronic restraint stress for 6hr/day/21days (STR-IMM). Some rats, underwent a post-stress rest period for 6- or 3-weeks after the end of stress (STR-R6, STR-R3). Control (CON) rats were unrestrained for the duration of the experiment. In Experiment 1, following the stress or rest manipulation, all rats were acclimated to conditioning and extinction contexts, fear conditioned with 3 tone-foot shock pairings, and then had two days of extinction training. All groups froze similarly to the tone across all training sessions. However, STR-R6/R3 froze less in the non-shock context than did STR-IMM or CON. During extinction training, STR-IMM showed high levels of freezing to the non-shock context, leading to a concern they may be generalizing across contexts. Consequently, a follow-up experiment tested for context generalization. In Experiment 2, STR-IMM rats underwent a generalization test in an environment that was either different or the same as the conditioning environment, using STR-R6 as a comparison. STR-IMM and STR-R6 showed similar relative levels of freezing to tone and context, regardless of their conditioning environment to reveal that STR-IMM did not generalize and instead, maybe expressing hypervigilance. Thus, the present study demonstrated the novel finding that a rest period from chronic stress can lead to reduced fear responsiveness in a non-shock environment.
ContributorsJudd, Jessica M (Author) / Conrad, Cheryl D. (Thesis advisor) / Sanabria, Federico (Committee member) / Smith, Brian (Committee member) / Arizona State University (Publisher)
Created2018
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Exertional heat stroke continues to be one of the leading causes of illness and death in sport in the United States, with an athlete’s experienced microclimate varying by venue design and location. A limited number of studies have attempted to determine the relationship between observed wet bulb globe temperature (WBGT)

Exertional heat stroke continues to be one of the leading causes of illness and death in sport in the United States, with an athlete’s experienced microclimate varying by venue design and location. A limited number of studies have attempted to determine the relationship between observed wet bulb globe temperature (WBGT) and WBGT derived from regional weather station data. Moreover, only one study has quantified the relationship between regionally modeled and on-site measured WBGT over different athletic surfaces (natural grass, rubber track, and concrete tennis court). The current research expands on previous studies to examine how different athletic surfaces influence the thermal environment in the Phoenix Metropolitan Area using a combination of fieldwork, modeling, and statistical analysis. Meteorological data were collected from 0700–1900hr across 6 days in June and 5 days in August 2019 in Tempe, Arizona at various Sun Devil Athletics facilities. This research also explored the influence of surface temperatures on WBGT and the changes projected under a future warmer climate. Results indicate that based on American College of Sports Medicine guidelines practice would not be cancelled in June (WBGT≥32.3°C); however, in August, ~33% of practice time was lost across multiple surfaces. The second-tier recommendations (WBGT≥30.1°C) to limit intense exercise were reached an average of 7 hours each day for all surfaces in August. Further, WBGT was calculated using data from four Arizona Meteorological Network (AZMET) weather stations to provide regional WBGT values for comparison. The on-site (field/court) WBGT values were consistently higher than regional values and significantly different (p<0.05). Thus, using regionally-modeled WBGT data to guide activity or clothing modification for heat safety may lead to misclassification and unsafe conditions. Surface temperature measurements indicate a maximum temperature (170°F) occurring around solar noon, yet WBGT reached its highest level mid-afternoon and on the artificial turf surface (2–5PM). Climate projections show that WBGT values are expected to rise, further restricting the amount of practice and games than can take place outdoors during the afternoon. The findings from this study can be used to inform athletic trainers and coaches about the thermal environment through WBGT values on-field.

ContributorsGuyer, Haven Elizabeth (Author) / Vanos, Jennifer K. (Thesis advisor) / Georgescu, Matei (Thesis advisor) / Hondula, David M. (Committee member) / Arizona State University (Publisher)
Created2020
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Interdisciplinary research has highlighted how social-ecological dynamics drive the structure and function of the urban landscape across multiple scales. Land management decisions operate across various levels, from individuals in their backyard to local municipalities and broader political-economic forces. These decisions then scale up and down across the landscape to influence

Interdisciplinary research has highlighted how social-ecological dynamics drive the structure and function of the urban landscape across multiple scales. Land management decisions operate across various levels, from individuals in their backyard to local municipalities and broader political-economic forces. These decisions then scale up and down across the landscape to influence ecological functioning, such as the provisioning of biodiversity. Likewise, people are influenced by, and respond to, their environment. However, there is a lack of integrated research, especially research that considers the spatial and temporal complexities of social-ecological dynamics, to fully understand how people influence ecosystems or how the resulting landscape in turn influences human decision making, attitudes, and well-being.

My dissertation connects these interdisciplinary themes to examine three questions linked by their investigation of the interactions between people and biodiversity: (1) How do the social and spatial patterns within an arid city affect people’s attitudes about their regional desert environment? (2) How are novel communities in cities assembled given the social-ecological dynamics that influence the processes that structure ecological communities? (3) How can we reposition bird species traits into a conservation framework that explains the complexity of the interactions between people and urban bird communities? I found that social-ecological dynamics between people, the environment, and biodiversity are tightly interwoven in urban ecosystems. The regional desert environment shapes people’s attitudes along spatial and social configurations, which holds implications for yard management decisions. Multi-scalar management decisions then influence biodiversity throughout cities, which shifts public perceptions of urban nature. Overall, my research acts as a bridge between social and ecological sciences to theoretically and empirically integrate research focused on biodiversity conservation in complex, social-ecological systems. My goal as a scholar is to understand the balance between social and ecological implications of landscape change to support human well-being and promote biodiversity conservation.

ContributorsAndrade, Riley (Author) / Franklin, Janet (Thesis advisor) / Larson, Kelli L (Thesis advisor) / Hondula, David M. (Committee member) / Lerman, Susannah B (Committee member) / Arizona State University (Publisher)
Created2020
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Desert ecosystems of the southwest United States are characterized by hot and arid climates, but hibernating bats can be found at high altitudes. The emerging fungal infection, white-nose syndrome, causes mortality in hibernating bat populations across eastern North America and the pathogen is increasingly observed in western regions. However, little

Desert ecosystems of the southwest United States are characterized by hot and arid climates, but hibernating bats can be found at high altitudes. The emerging fungal infection, white-nose syndrome, causes mortality in hibernating bat populations across eastern North America and the pathogen is increasingly observed in western regions. However, little is known about the ecology of hibernating bats in the southwest, which can help predict how these populations may respond to the fungus. My study investigated hibernating bats during two winters (2018-2019/2019-2020) at three caves in northern Arizona to: (1) describe diversity and abundance of hibernating bats using visual internal surveys and photographic documentation, (2) determine the duration of hibernation by recording bat echolocation call sequences outside caves and recording bat activity in caves using visual inspection, and (3) describe environmental conditions where hibernating bats are roosting. Adjacent to bats, I collected temperature and relative humidity, which I converted into absolute humidity. I documented hibernation status (i.e. active vs. not active) and roosting body position (i.e. open, partially hidden, and hidden). Between September 2018 and April 2019, 246 bat observations were recorded across the three caves. The majority of bats were identified as Myotis spp. (45.9\%, n=113), followed by Corynorhinus townsendii (45.5\%, n=112), Parastrellus hesperus (4.8\%, n=12), Eptesicus fuscus (3.6\%, n=9). Between September 2019 and April 2020, I documented a total of 361 bat observations across the three caves. C. townsendii was most prevalent (52.9\%, n=191), followed by the category P. hesperus/Myotis spp. (25.7\%, n=93), Myotis spp. (12.4\%, n=45), P. Hesperus (4.4\%, n=16), E. fuscus (3.6\%, n=13) and Unknown (0.8\%, n=3). Average conditions adjacent to bats were, temperature=12.5ºC, relative humidity=53\%, and absolute humidity=4.9 g/kg. Hibernating bats were never observed in large clusters and the maximum hibernating population size was 24, suggesting low risk for pathogen transmission among bats. Hibernation lasted approximately 120 days, with minimal activity documented inside and outside caves. Hibernating bats in northern Arizona may be at low risk for white-nose syndrome based on population size, hibernation length, roosting behavior, and absolute humidity, but other variables (e.g. temperature) indicate the potential for white-nose syndrome impacts on these populations.
ContributorsMaldonado Perez, Nubia Erandi (Author) / Moore, Marianne S (Thesis advisor) / DeNardo, Dale (Committee member) / Deviche, Pierre (Committee member) / Smith, Brian (Committee member) / Arizona State University (Publisher)
Created2020
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This study aimed to investigate the effects of specific macronutrient feedings on competitive golf performance and perceived levels of fatigue and alertness. Participants played three, nine hole rounds of golf, consuming an isocaloric beverage as a control (CON), with the addition of carbohydrate (CHO), or combination of protein and carbohydrate

This study aimed to investigate the effects of specific macronutrient feedings on competitive golf performance and perceived levels of fatigue and alertness. Participants played three, nine hole rounds of golf, consuming an isocaloric beverage as a control (CON), with the addition of carbohydrate (CHO), or combination of protein and carbohydrate (COM). Physiological and performance measurements were taken before, during, and following each nine hole round. Performance measurements include driving accuracy (DA), driving distance (DD), iron accuracy (IA), chipping accuracy (CA), and putting accuracy (PA). Pre-golf hydration status (urine specific gravity [USG]) and Sweat Rate during golf performance showed no significant differences between trials. All nine hole rounds were performed in ~2 hours. Environmental conditions were similar for all three testing days (mean WBGT=10.946). No significant differences were seen in Driving Distance, Driving Accuracy, and Iron Accuracy for all nine holes between groups receiving different macronutrient feedings. Chipping Accuracy was significantly better in CON trial compared to CHO (p=0.004) and COM (p=0.019). No significant differences were seen in putting make percentages. COM trial significantly lowered Perceived Levels of Fatigue (p=0.019) compared to CON. The CHO trial showed significant improvements in DA compared to CON (13.7 vs. 44.1, p=0.012) and COM (13.7 vs. 33.6, p=0.004) in the first four holes. In the last five holes, the COM trial showed significant improvements in DA compared to CHO (17.5 vs. 29.7, p=0.007). Low Handicap golfers (3 +/- 3) performed significantly better than High Handicap golfers (14 +/- 3.6) in DD (265 vs. 241, p<0.001), DA (15.0 vs. 29.3, p=0.004), IA (15.2 vs. 25.2, p<0.001), CA (52.0 vs. 61.5, p=0.027), and PA 5ft (64% vs. 40%, p=0.003). High Handicap players showed no significant differences between the three trials for any golf performance measurements. Low Handicap players showed significant improvements in DA for COM trial compared to CON trial (13.6 vs. 27.6, p=0.003). The results suggest that carbohydrates at the start and a combination of carbohydrate and protein is beneficial at the second part of 9 holes to improve golf performance and maintain levels of fatigue, however, it needs to be investigated how this knowledge will relate to playing more holes.

ContributorsThompsett, Daniel James (Author) / Wardenaar, Floris (Thesis advisor) / Der Ananian, Cheryl (Committee member) / Hondula, David M. (Committee member) / Arizona State University (Publisher)
Created2020
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Urban heat is a growing problem that impacts public health, water and energy use, and the economy and affects population subgroups differently. Exposure and sensitivity, two key factors in determining vulnerability, have been widely researched. This dissertation focuses on the adaptive capacity component of heat vulnerability at the individual, household,

Urban heat is a growing problem that impacts public health, water and energy use, and the economy and affects population subgroups differently. Exposure and sensitivity, two key factors in determining vulnerability, have been widely researched. This dissertation focuses on the adaptive capacity component of heat vulnerability at the individual, household, and community scale. Using a mixed methods approach and metropolitan Phoenix as a test site, I explored how vulnerable communities understand and adapt to increasing extreme urban heat to uncover adaptive capacity that is not being operationalized well through current heat vulnerability frameworks. Twenty-three open-ended interviews were conducted where residents were encouraged to tell their stories about past and present extreme heat adaptive capacity behaviors. A community-based participatory research project consisting of three workshops and demonstration projects was piloted in three underserved neighborhoods to address urban heat on a local scale and collaboratively create community heat action plans. Last, a practitioner stakeholder meeting was held to discuss how the heat action plans will be integrated into other community efforts. Using data from the interviews, workshops, and stakeholder meeting, social capital was examined in the context of urban heat. Although social capital has been measured in a multitude of ways to gauge social relationships, trust, and reciprocity within a community, it is situational and reflects a position within the formal and informal aspects of any issue. Three narratives emerged from the interviews illuminating differentiated capacities to cope with urban heat: heat is an inconvenience, heat is a manageable problem, and heat is a catastrophe. For each of these narratives, generic adaptive capacity is impacted differently by specific heat adaptive capacity. The heat action plan workshops generated hyper-local heat solutions that reflected the neighborhoods’ different identities. Community-based organizations were instrumental in the success of this program. Social capital indicators were developed specific to urban heat that rely on heavily on family and personal relationships, attitudes and beliefs, perceived support, network size and community engagement. This research highlights how extreme heat vulnerability may need to be rethought to capture adaptive capacity nuances and the dynamic structure of who is vulnerable under what circumstances.

ContributorsGuardaro, Melissa (Author) / Redman, Charles L. (Thesis advisor) / Hondula, David M. (Committee member) / Johnston, Erik W., 1977- (Committee member) / Arizona State University (Publisher)
Created2019
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Moderate physical activity, such as walking and biking, positively affects physical and mental health. Outdoor thermal comfort is an important prerequisite for incentivizing an active lifestyle. Thus, extreme heat poses significant challenges for people who are outdoors by choice or necessity. The type and qualities of built infrastructure determine the

Moderate physical activity, such as walking and biking, positively affects physical and mental health. Outdoor thermal comfort is an important prerequisite for incentivizing an active lifestyle. Thus, extreme heat poses significant challenges for people who are outdoors by choice or necessity. The type and qualities of built infrastructure determine the intensity and duration of individual exposure to heat. As cities globally are shifting priorities towards non-motorized and public transit travel, more residents are expected to experience the city on their feet. Thus, physical conditions as well as psychological perception of the environment that affect thermal comfort will become paramount. Phoenix, Arizona, is used as a case study to examine the effectiveness of current public transit and street infrastructure to reduce heat exposure and affect the thermal comfort of walkers and public transit users.

The City of Phoenix has committed to public transit improvements in the Transportation 2050 plan and has recently adopted a Complete Streets Policy. Proposed changes include mobility improvements and creating a safe and comfortable environment for non-motorized road participants. To understand what kind of improvements would benefit thermal comfort the most, it is necessary to understand heat exposure at finer spatial scales, explore whether current bus shelter designs are adequate in mitigating heat-health effects, and comprehensively assess the impact of design on physical, psychological and behavioral aspects of thermal comfort. A study conducted at bus stops in one Phoenix neighborhood examined grey and green infrastructure types preferred for cooling and found relationships between perception of pleasantness and thermal sensation votes. Walking interviews conducted in another neighborhood event examined the applicability of a framework for walking behavior under the stress of heat, and how differences between the streets affected perceptions of the walkers. The interviews revealed that many of the structural themes from the framework of walking behavior were applicable, however, participants assessed the majority of the elements in their walk from a heat mitigation perspective. Finally, guiding questions for walkability in hot and arid climates were developed based on the literature review and results from the empirical studies. This dissertation contributes to filling the gap between walkability and outdoor thermal comfort, and presents methodology and findings that can be useful to address walkability and outdoor thermal comfort in the world’s hot cities as well as those in temperate climates that may face similar climate challenges in the future as the planet warms.
ContributorsDzyuban, Yuliya (Author) / Redman, Charles L. (Thesis advisor) / Coseo, Paul J. (Committee member) / Hondula, David M. (Committee member) / Arizona State University (Publisher)
Created2019