Matching Items (118)
Filtering by
Description
The elaborate signals of animals are often costly to produce and maintain, thus communicating reliable information about the quality of an individual to potential mates or competitors. The properties of the sensory systems that receive signals can drive the evolution of these signals and shape their form and function. However, relatively little is known about the ecological and physiological constraints that may influence the development and maintenance of sensory systems. In the house finch (Carpodacus mexicanus) and many other bird species, carotenoid pigments are used to create colorful sexually selected displays, and their expression is limited by health and dietary access to carotenoids. Carotenoids also accumulate in the avian retina, protecting it from photodamage and tuning color vision. Analogous to plumage carotenoid accumulation, I hypothesized that avian vision is subject to environmental and physiological constraints imposed by the acquisition and allocation of carotenoids. To test this hypothesis, I carried out a series of field and captive studies of the house finch to assess natural variation in and correlates of retinal carotenoid accumulation and to experimentally investigate the effects of dietary carotenoid availability, immune activation, and light exposure on retinal carotenoid accumulation. Moreover, through dietary manipulations of retinal carotenoid accumulation, I tested the impacts of carotenoid accumulation on visually mediated foraging and mate choice behaviors. My results indicate that avian retinal carotenoid accumulation is variable and significantly influenced by dietary carotenoid availability and immune system activity. Behavioral studies suggest that retinal carotenoid accumulation influences visual foraging performance and mediates a trade-off between color discrimination and photoreceptor sensitivity under dim-light conditions. Retinal accumulation did not influence female choice for male carotenoid-based coloration, indicating that a direct link between retinal accumulation and sexual selection for coloration is unlikely. However, retinal carotenoid accumulation in males was positively correlated with their plumage coloration. Thus, carotenoid-mediated visual health and performance or may be part of the information encoded in sexually selected coloration.
ContributorsToomey, Matthew (Author) / McGraw, Kevin J. (Thesis advisor) / Deviche, Pierre (Committee member) / Smith, Brian (Committee member) / Rutowski, Ronald (Committee member) / Verrelli, Brian (Committee member) / Arizona State University (Publisher)
Created2011
Description
Does school participatory budgeting (SPB) increase students’ political efficacy? SPB, which is implemented in thousands of schools around the world, is a democratic process of deliberation and decision-making in which students determine how to spend a portion of the school’s budget. We examined the impact of SPB on political efficacy in one middle school in Arizona. Our participants’ (n = 28) responses on survey items designed to measure self-perceived growth in political efficacy indicated a large effect size (Cohen’s d = 1.46), suggesting that SPB is an effective approach to civic pedagogy, with promising prospects for developing students’ political efficacy.
ContributorsGibbs, Norman P. (Author) / Bartlett, Tara Lynn (Author) / Schugurensky, Daniel, 1958- (Author)
Created2021-05-01
Description
Patients with Alzheimer's disease (AD) exhibit a significantly higher incidence of unprovoked seizures compared to age-matched non-AD controls, and animal models of AD (i.e., transgenic human amyloid precursor protein, hAPP mice) display neural hyper-excitation and epileptic seizures. Hyperexcitation is particularly important because it contributes to the high incidence of epilepsy in AD patients as well as AD-related synaptic deficits and neurodegeneration. Given that there is significant amyloid-β (Aβ) accumulation and deposition in AD brain, Aβ exposure ultimately may be responsible for neural hyper-excitation in both AD patients and animal models. Emerging evidence indicates that α7 nicotinic acetylcholine receptors (α7-nAChR) are involved in AD pathology, because synaptic impairment and learning and memory deficits in a hAPPα7-/- mouse model are decreased by nAChR α7 subunit gene deletion. Given that Aβ potently modulates α7-nAChR function, that α7-nAChR expression is significantly enhanced in both AD patients and animal models, and that α7-nAChR play an important role in regulating neuronal excitability, it is reasonable that α7-nAChRs may contribute to Aβ-induced neural hyperexcitation. We hypothesize that increased α7-nAChR expression and function as a consequence of Aβ exposure is important in Aβ-induced neural hyperexcitation. In this project, we found that exposure of Aβ aggregates at a nanomolar range induces neuronal hyperexcitation and toxicity via an upregulation of α7-nAChR in cultured hippocampus pyramidal neurons. Aβ up-regulates α7-nAChRs function and expression through a post translational mechanism. α7-nAChR up-regulation occurs prior to Aβ-induced neuronal hyperexcitation and toxicity. Moreover, inhibition of α7-nAChR or deletion of α7-nAChR prevented Aβ induced neuronal hyperexcitation and toxicity, which suggests that α7-nAChRs are required for Aβ induced neuronal hyperexcitation and toxicity. These results reveal a profound role for α7-nAChR in mediating Aβ-induced neuronal hyperexcitation and toxicity and predict that Aβ-induced up-regulation of α7-nAChR could be an early and critical event in AD etiopathogenesis. Drugs targeting α7-nAChR or seizure activity could be viable therapies for AD treatment.
ContributorsLiu, Qiang (Author) / Wu, Jie (Thesis advisor) / Lukas, Ronald J (Committee member) / Chang, Yongchang (Committee member) / Sierks, Michael (Committee member) / Smith, Brian (Committee member) / Vu, Eric (Committee member) / Arizona State University (Publisher)
Created2011
Description
Since the introduction of the common school in the United States (US), education has constantly been in a state of reform. Given the importance of student learning to the future state of our nation, it is important to understand how positive educational reform can be achieved. This ethnographic case study aims to try to understand how a reform effort works as an educational and a sociocultural process, and what the important contributing factors to actualizing school reform are, as well as the challenges of effective implementation. Specifically, this study focuses on a school-wide reform effort based upon Stephen Covey's Seven Habits (1989). Qualitative research methods were used to address the research questions in this study. The researcher drew upon interviews, observations, and artifact and field note collection to tell the story of an elementary school engaged in year three of a school-wide reform initiative from the viewpoint of 10 teachers involved. Three recurring themes emerged from the data. First, data indicate that school reform is most effective when a school culture is created that supports the activation of teacher voice, efficacy, and coparticipation. Second, time and support are factors impacting implementation. Third, teachers reported that the common language from the reform has impacted the culture of the school. The evolution of a school culture is not simple and is demonstrated in the different ways the teachers experience the reform. Questions of authenticity arise when the reform effort changes from a grassroots, bottom-up initiative to a more top-down, bureaucratized business model.
ContributorsLamp, Michelle (Author) / Mccarty, Teresa (Thesis advisor) / Schugurensky, Daniel, 1958- (Committee member) / Powers, Jeanne (Committee member) / Arizona State University (Publisher)
Created2013
Description
Providing nutrition information at point of sale at restaurants has gained in popularity in recent years and will soon become a legal requirement. Consumers are using this opportunity to become more informed on the nutritional quality of the foods they consume in an effort to maintain healthfulness. Prior research has confirmed the utility of this information in adult populations. However, research on adolescents in school environments has resulted in mixed findings. This study investigated the effect of exposure to calorie and fat information on student purchases at lunchtime in a high school cafeteria. Additionally, it explored other factors that may contribute to students' food selections during school lunches. The research methods included analysis of changes in cafeteria food sales in one school, surveys, and focus groups. Analysis of cafeteria food sales during lunch did not show any significant change in the average number of calories and fat purchased per student between pre and post intervention. However, information gathered from focus group questioning demonstrated how students used the nutrition information to change their behavior after they have purchased their food.
ContributorsFresques, Audrey Delfina (Author) / Schugurensky, Daniel, 1958- (Thesis advisor) / Barnett, Joshua (Committee member) / Cruz, Heather (Committee member) / Arizona State University (Publisher)
Created2013
Description
The purpose of this study is to examine the influence of neoliberalism on the occurrence and intervention of genocide, particularly the ability to create othered groups through a process of dehumanization that desensitizes those in power to the human condition. I propose Social Externalization Theory as paradigm that explains how neoliberalism can be used as a means social control to create subjects vulnerable to political and collective violence that is justified as the externalized cost of economic growth, development, and national security. Finally, the conflict in Darfur (2003 - 2010) serves as a case study to analyze the influence of neoliberal policies on the resistance of the International community to recognize the violence as genocide. Analysis of the case study found that some tenets of neoliberalism produce results that fit within the ideologies of genocide and that some aspects of neoliberalism assume a genocidal mentality. In this case, those in positions power engage in daily activities that justify some suffering as acceptable, thus desensitizing them to the harm that their decisions generate.
ContributorsCalleja, Robert J (Author) / Romero, Mary (Thesis advisor) / Swadener, Beth Blue (Committee member) / Schugurensky, Daniel, 1958- (Committee member) / Arizona State University (Publisher)
Created2013
Description
Specific dendritic morphologies are a hallmark of neuronal identity, circuit assembly, and behaviorally relevant function. Despite the importance of dendrites in brain health and disease, the functional consequences of dendritic shape remain largely unknown. This dissertation addresses two fundamental and interrelated aspects of dendrite neurobiology. First, by utilizing the genetic power of Drosophila melanogaster, these studies assess the developmental mechanisms underlying single neuron morphology, and subsequently investigate the functional and behavioral consequences resulting from developmental irregularity. Significant insights into the molecular mechanisms that contribute to dendrite development come from studies of Down syndrome cell adhesion molecule (Dscam). While these findings have been garnered primarily from sensory neurons whose arbors innervate a two-dimensional plane, it is likely that the principles apply in three-dimensional central neurons that provide the structural substrate for synaptic input and neural circuit formation. As such, this dissertation supports the hypothesis that neuron type impacts the realization of Dscam function. In fact, in Drosophila motoneurons, Dscam serves a previously unknown cell-autonomous function in dendrite growth. Dscam manipulations produced a range of dendritic phenotypes with alteration in branch number and length. Subsequent experiments exploited the dendritic alterations produced by Dscam manipulations in order to correlate dendritic structure with the suggested function of these neurons. These data indicate that basic motoneuron function and behavior are maintained even in the absence of all adult dendrites within the same neuron. By contrast, dendrites are required for adjusting motoneuron responses to specific challenging behavioral requirements. Here, I establish a direct link between dendritic structure and neuronal function at the level of the single cell, thus defining the structural substrates necessary for conferring various aspects of functional motor output. Taken together, information gathered from these studies can inform the quest in deciphering how complex cell morphologies and networks form and are precisely linked to their function.
ContributorsHutchinson, Katie Marie (Author) / Duch, Carsten (Thesis advisor) / Neisewander, Janet (Thesis advisor) / Newfeld, Stuart (Committee member) / Smith, Brian (Committee member) / Orchinik, Miles (Committee member) / Arizona State University (Publisher)
Created2013
Description
This dissertation explores the unique role schools play in contributing toward a sustainable future for their communities. This was undertaken by first conducting a thorough review and analysis of the literature on the current utilization of schools as agents of sustainable development, along with an evaluation of schools engaging in this model around the United States. Following this, a framework was developed to aid in the assessment of school-community engagements from the perspective of social change. Sustainability problem solving tools were synthesized for use by schools and community stakeholders, and were tested in the case study of this dissertation. This case study combined methods from the fields of sustainable development, transition management, and social change to guide two schools in their attempts to increase community sustainability through addressing a shared sustainability problem: childhood obesity. The case study facilitated the creation of a sustainable vision for the Phoenix Metropolitan Area without childhood obesity, as well as strategic actions plans for each school to utilize as they move forward on addressing this challenge.
ContributorsLawless, Tamara Hope (Author) / Golub, Aaron (Thesis advisor) / Redman, Charles (Committee member) / Schugurensky, Daniel, 1958- (Committee member) / Arizona State University (Publisher)
Created2013
Description
Sustainability challenges with severe local to global impacts require fundamental shifts in what industrial societies aspire to, generate, consume, and represent, as well as how they function. Transition governance is a promising framework to support these transformational efforts. A key component of transition governance is the construction of transition strategies, i.e., action schemes for how to transition from the current state to a sustainable one. Despite accomplishments in building theory and methodology for transition governance, the concepts of what transition strategies entail and how they relate to specific interventions are still underdeveloped. This dissertation further develops the concept of transition strategies, and explores how different stakeholder groups and allies can develop and test transition strategies across different scales, in the specific context of urban sustainability challenges. The overarching research question is: How can cities build and implement comprehensive transition strategies across different urban scales, from the city to the organizational level? The dissertation comprises four studies that explore the dynamic between transition strategies and experiments at the city, neighborhood, and organizational levels with empirical examples from Phoenix, Arizona. The first study reviews and compares paradigms of intentional change, namely transition governance, backcasting, intervention research, change management, integrated planning, and adaptive management in order to offer a rich set of converging ideas on what strategies for intentional change towards sustainability entail. The second study proposes a comprehensive concept of transition strategies and illustrates the concept with the example of sustainability strategies created through a research partnership with the City of Phoenix. The third study explores the role of experiments in transition processes through the lens of the neighborhood-level initiative of The Valley of the Sunflowers. The fourth study examines the role organizations can play in initiating urban sustainability transitions using exemplary strategies and experiments implemented at a local high school. The studies combined contribute to the further development of transition theory and sustainable urban development concepts. While this research field is at a nascent stage, the thesis provides a framework and empirical examples for how to build evidence-based transition strategies in support of urban sustainability.
ContributorsKay, Braden Ryan (Author) / Wiek, Arnim (Thesis advisor) / Loorbach, Derk (Committee member) / Schugurensky, Daniel, 1958- (Committee member) / Tiger, Fern (Committee member) / Arizona State University (Publisher)
Created2012
Description
The Empowerment Zones were created in 1993 under Clinton's administration, demonstrating a commitment to solving tough socio-economic problems in distressed communities. The main objective associated with this program was economic recovery of distressed communities by creating jobs and providing various services to the indigenous populations. The designation of the Empowerment Zones went in three rounds (1994, 1998, and 2001), and although the types and amounts of federal incentives varied across rounds, the four principles around which the program originated remain unchanged: strategic vision for change, community based partnerships, economic opportunity, and sustainable community development. Since its inception, the Empowerment Zones program has been implemented in 30 urban and 10 rural communities in 27 states across the U.S. Two central questions lead the research of this dissertation project: 1) What have been the main accomplishments of the round three federal Empowerment Zones program in Tucson? 2) What have been the main challenges of the round three federal Empowerment Zones program in Tucson? By using a case study research design and various techniques for data collection and analysis (including the program package Atlas.ti), this study examined the accomplishments and the challenges associated with the round three designated Empowerment Zone in Tucson. Evidence was collected from multiple sources, including 24 interviews, over 60 local newspaper articles, relevant documentation, annual performance reports, and other sources. The analysis reveals that the program's implementation in Tucson was strong in the beginning, but after two years, the earlier success started to fade quickly. The shortcomings of program design became evident during the implementation phase and further in the inability of the administration to collect relevant data to demonstrate the program's success. The consequences of the inability to provide data for program evaluation influenced the enthusiasm of the administrators and program partners, and weakened the political support. The reduction in the grant component contributed to overemphasis of the business development component thereby ignoring most community development aspects essential for the success of the program in Tucson. This study did not find evidence for the claim that round three of the empowerment zones program based on federal tax incentives contributes to the creation of new jobs and the attraction of new business in economically deprived communities in Tucson.
ContributorsAndonoska, Ljubinka (Author) / Schugurensky, Daniel, 1958- (Thesis advisor) / Miller, Gerald J. (Committee member) / Svara, James H. (Committee member) / Arizona State University (Publisher)
Created2013