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- Creators: Arizona State University
- Creators: Sadusky, Brian
- Resource Type: Text
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
At the heart of every eusocial insect colony is a reproductive division of labor. This division can emerge through dominance interactions at the adult stage or through the production of distinct queen and worker castes at the larval stage. In both cases, this division depends on plasticity within an individual to develop reproductive characteristics or serve as a worker. In order to gain insight into the evolution of reproductive plasticity in the social insects, I investigated caste determination and dominance in the ant Harpegnathos saltator, a species that retains a number of ancestral characteristics. Treatment of worker larvae with a juvenile hormone (JH) analog induced late-instar larvae to develop as queens. At the colony level, workers must have a mechanism to regulate larval development to prevent queens from developing out of season. I identified a new behavior in H. saltator where workers bite larvae to inhibit queen determination. Workers could identify larval caste based on a chemical signal specific to queen-destined larvae, and the production of this signal was directly linked to increased JH levels. This association provides a connection between the physiological factors that induce queen development and the production of a caste-specific larval signal. In addition to caste determination at the larval stage, adult workers of H. saltator compete to establish a reproductive hierarchy. Unlike other social insects, dominance in H. saltator was not related to differences in JH or ecdysteroid levels. Instead, changes in brain levels of biogenic amines, particularly dopamine, were correlated with dominance and reproductive status. Receptor genes for dopamine were expressed in both the brain and ovaries of H. saltator, and this suggests that dopamine may coordinate changes in behavior at the neurological level with ovarian status. Together, these studies build on our understanding of reproductive plasticity in social insects and provide insight into the evolution of a reproductive division of labor.
ContributorsPenick, Clint A (Author) / Liebig, Jürgen (Thesis advisor) / Brent, Colin (Committee member) / Gadau, Jürgen (Committee member) / Hölldobler, Bert (Committee member) / Rutowski, Ron (Committee member) / Arizona State University (Publisher)
Created2012
Description
Water is the defining issue in determining the development and growth of human populations of the Southwest. The cities of Las Vegas, Phoenix, Tucson, Albuquerque, and El Paso have experienced rapid and exponential growth over the past 50 years. The outlook for having access to sustainable sources of water to support this growth is not promising due to water demand and supply deficits. Regional water projects have harnessed the Colorado and Rio Grande rivers to maximize the utility of the water for human consumption and environmental laws have been adopted to regulate the beneficial use of this water, but it still is not enough to create sustainable future for rapidly growing southwest cities. Future growth in these cities will depend on finding new sources of water and creative measures to maximize the utility of existing water resources. The challenge for southwest cities is to establish policies, procedures, and projects that maximizes the use of water and promotes conservation from all areas of municipal users. All cities are faced with the same challenges, but have different options for how they prioritize their water resources. The principal means of sustainable water management include recovery, recharge, reuse, and increasing the efficiency of water delivery. Other strategies that have been adopted include harvesting of rainwater, building codes that promote efficient water use, tiered water rates, turf removal programs, residential water auditing, and native plant promotion. Creating a sustainable future for the southwest will best be achieved by cities that adopt an integrated approach to managing their water resources including discouraging discretionary uses of water, adoption of building and construction codes for master plans, industrial plants, and residential construction. Additionally, a robust plan for education of the public is essential to create a culture of conservation from a very young age.
ContributorsMalloy, Richard (Richard A.) (Author) / Brock, John (Thesis advisor) / Martin, Chris (Thesis advisor) / Thor, Eric (Committee member) / Arizona State University (Publisher)
Created2013
Description
ABSTRACT The present study examined the relationship between the experience of trauma during childhood (ages birth -12 years) and life satisfaction in adulthood (ages of 30-45) in a sample of convenience consisting of eight (8) adults, six (6) women and two (2) men, who volunteered to participate in this qualitative study, and self-identified as having experienced trauma between birth and age 12 years. Participants were asked to describe the trauma(s) they experienced in childhood and to discuss their thoughts and feelings about present circumstances in their lives, and how their lives have been impacted by the trauma they experienced. Data were collected via in-person interviews that were audio-taped and transcribed. The data were analyzed using a process of thematic coding. Nine (9) emotional themes were identified: aggression, anger, fear, frustration, helplessness, insecurity, irritability, loneliness and sadness. Participants reported a variety of traumas experienced, and their responses to difficult experiences were varied. Participants reported being impacted differently in eight domains of life that were examined in the study: mood related problems, self-care, social support, primary partner relationship, career, decision to have children, parenting and adult life satisfaction. All participants stated they had been impacted by early life trauma, and all stated that early-experienced trauma(s) had an impact on their life satisfaction in adulthood. Inter-coder reliability for emotional thematic codes and domains of life impacted by early trauma was .82.
ContributorsCrawford, Sarah (Author) / Moore, Elsie (Thesis advisor) / Stamm, Jill (Committee member) / Caterino, Linda (Committee member) / Arizona State University (Publisher)
Created2013
Description
Research regarding social competence is growing rapidly, but there remain a few aspects of social development that merit more attention. The presented pair of studies were planned to address two such areas in the social development literature, specifically the longitudinal trajectories of social competence and the role of social competence in second language development in language minority (LM) students. The goal of the first investigation was to examine the developmental trends of interpersonal skills (IS) across the early childhood and elementary school years in a nationally representative, U.S. sample. The goal of the second study was to examine whether differing trajectories of IS development in language minority children in the U.S. were related to their language and literacy (LL) skills at grade 5. Both studies utilized data from the Early Childhood Longitudinal Study - Kindergarten Class of 1998-1999 and modeled ratings of children's IS at five time points between fall of kindergarten and spring of fifth grade using latent class growth analyses in Mplus. In study 1, the best model was a quadratic two-class latent class growth analysis. Trajectory class 1 was a higher-level path with a marginally significant non-linear shape and class 2 was a primarily stable, moderate level path with a slight, non-significant increase over time. The same pattern of results emerged for both boys and girls separately as with the combined-sex model, and in all three final models the proportion of the sample in the higher-level class was greater than the moderate-level class. In study 2 a sample of U.S. children whose primary language at home was something other than English was utilized. LL at the start of kindergarten and sex were included as covariates and LL in fifth grade as a distal outcome. The best model for the data was a cubic two-class latent class growth analysis. Class 1 followed a higher-level path with small, incremental change over time and class 2 was a moderate-level path with greater undulation. Both covariates significantly predicted latent class and language and literacy scores at grade 5 differed significantly across classes.
ContributorsDiDonato, Alicia (Author) / Wilcox, M. Jeanne (Thesis advisor) / Bradley, Robert (Committee member) / Wilkens, Natalie (Committee member) / Valiente, Carlos (Committee member) / Arizona State University (Publisher)
Created2014
Description
The main purpose of this dissertation is to examine the effects of migration and household capitals on agricultural and energy transitions in the setting of rapidly changing socioeconomic and environmental conditions of Chitwan, Nepal. The environmental aspects of agricultural and energy transitions are also discussed to weave the changes in the livelihoods of rural households into the discourse of sustainable development, especially in the context of underdeveloped countries. The data used for the analysis is the Chitwan Valley Family Study which has been collected since 1996 at the individual and household level with the focuses on agriculture and family. The results from first difference model and multilevel logistic regression model using discrete-time event history approach deliver a couple of important messages for the future plans for local and national development. Most of all, migration plays an important role in the livelihoods of rural households in Chitwan. It might not have a direct impact, but the findings indicate that social and financial remittances from migration interact with how a household utilizes their current capitals under a given context for the future. Particularly, available labor in a household, prior investment in agriculture, exposure to modern life style, and what other people do, all these factors moderate the association between migration and the transitions. The implications of these results on sustainable development for the future of Chitwan and Nepal in the coming years are discussed afterwards.
ContributorsHan, Seung Yong (Author) / Yabiku, Scott T. (Thesis advisor) / Glick, Jennifer E. (Committee member) / Agadjanian, Victor (Committee member) / Arizona State University (Publisher)
Created2014
Description
Despite a wealth of academic literature critiquing current tensions within the Fair Trade (FT) movement, very little work has focused on examining the birth and evolution of the FT movement within the broader context of the international political economy (IPE), specifically in reference to the ideological and policy changes that ushered in an era of free trade and deregulated markets for both trade and finance. From such an optic, it is no longer enough to merely question the extent to which the market should be engaged. Rather, one must question whether the engagement of the market strips the movement of its power to affect long term development in local economies. Drawing upon the historical record, this thesis focuses attention on the complexity of the linkages that exist between political ideology, trade policy, and development. While Fair Trade is commonly understood to be a responsive effort to create more equitable trade relations with producers in the least developed countries, less emphasis is placed on understanding the state-centered political structures that contributed to a capitalist push-back and the implementation of today's liberalized trade policy, and yet to do so is absolutely critical if we are to gain a deeper understanding of the limits and constraints of Fair Trade. Full engagement with mainstream markets has led to robust growth in the FT market per annum, yet countries that are heavily engaged with the FT market show little evidence of development or poverty reduction at a macro-level. Thus, Fair Trade must define itself as more than principled opposition to labor exploitation if it is to present itself as a credible instrument of economic development.
ContributorsSugata, Michihiro (Author) / Simmons, William (Thesis advisor) / Stancliff, Michael (Committee member) / Haglund, LaDawn (Committee member) / Arizona State University (Publisher)
Created2011
Description
The microfinance industry provides financial services to the world's poor in hopes of moving individuals and families out of poverty. This dissertation document suggests that information and communication technologies (ICTs) are changing the microfinance industry, especially given recent advancements in mobile banking, Internet usage and connectivity, and a decreasing digital divide. These impacts are discussed in three essays. First, ICTs impact intermediation among various players in the microfinance industry. Second, ICTs impact the extent to which microfinance institutions (MFIs) extend their outreach to poorer or more geographically remote borrowers. Finally, ICTs impact the location of decision rights given newly forming peer-to-peer (P2P) social microlending organizations. As the microfinance industry increases its adoption and reliance on ICTs, new and interesting opportunities abound for researchers in the information systems discipline.
ContributorsWeber, David Michael (Author) / Riggins, Frederick J. (Thesis advisor) / Kulkarni, Uday R. (Thesis advisor) / Carey, Jane M. (Committee member) / Arizona State University (Publisher)
Created2012
Description
Effective professional development has been shown to improve instruction and increase student academic achievement. The Train the Trainer professional development model is often chosen by the state Department of Education for its efficiency and cost effectiveness of delivering training to schools and districts widely distributed throughout the state. This is a study of the Train the Trainer component of an innovative K12 professional development model designed to meet the needs of the state's lowest performing schools that served some of the state's most marginalized students. Pursuing a Vygotzkian social constructivist framework, the model was developed and informed by its stakeholders, providing training that was collaborative, job-embedded, ongoing, and continuously adapted to meet the needs of the School Improvement Grant participants. Schools in the multi-case study were awarded the federal ARRA School Improvement Grant in 2010. Focus questions include: What influence does the Train the Trainer component have on classroom instruction specifically as it relates to formative assessment? and To what extent does the trainer support the implementation of the Train the Trainer professional development at the classroom level? The action research study took place from August 2011 to February 2012 and used a mixed-methods research design.
ContributorsPollnow, Shelly (Author) / Jimenez-Castellanos, Oscar (Thesis advisor) / Jimenez-Silva, Margarita (Committee member) / Williams, Susan (Committee member) / Arizona State University (Publisher)
Created2012
Description
Biculturalism embodies the degree to which individuals adapt to living within two cultural systems and develop the ability to live effectively across those two cultures. It represents, therefore, a normative developmental task among members of immigrant and ethnic-racial minority groups, and has important implications for psychosocial adjustment. Despite a strong theoretical focus on contextual influences in biculturalism scholarship, the ways in which proximal contexts shape its development are understudied. In my dissertation, I examine the mechanisms via which the family context might influence the development of bicultural competence among a socio-economically diverse sample of 749 U.S. Mexican-origin youths (30% Mexico-born) followed for 7 years (Mage = 10.44 to 17.38 years; Wave 1 to 4).
In study 1, I investigated how parents’ endorsements of values associated with both mainstream and heritage cultures relate to adolescents’ bicultural competence. Longitudinal growth model analyses revealed that parents’ endorsements of mainstream and heritage values simultaneously work to influence adolescents’ bicultural competence. By examining the effect of multiple and often competing familial contextual influences on adolescent bicultural competence development, this work provides insights on intergenerational cultural transmission and advances scholarship on the culturally bounded nature of human development.
In study 2, I offer a substantial extension to decades of family stress model research focused on how family environmental stressors may compromise parenting behaviors and youth development by testing a culturally informed family stress model. My model (a) incorporates family cultural and ecological stressors, (b) focuses on culturally salient parenting practices aimed to teach youth about the heritage culture (i.e., ethnic socialization), and (c) examines bicultural competence as a developmental outcome. Findings suggest that parents’ high exposure to ecological stressors do not compromise parental ethnic socialization or adolescent bicultural competence development. On the other hand, mothers’ exposures to enculturative stressors can disrupt maternal ethnic socialization, and in turn, undermine adolescents’ bicultural competence. By examining the influence of multiple family environmental stressors on culturally salient parenting practices, and their implications for adolescent bicultural competence development, this work provides insights on ethnic-racial minority and immigrant families’ adapting cultures and advances scholarship on the family stress model.
In study 1, I investigated how parents’ endorsements of values associated with both mainstream and heritage cultures relate to adolescents’ bicultural competence. Longitudinal growth model analyses revealed that parents’ endorsements of mainstream and heritage values simultaneously work to influence adolescents’ bicultural competence. By examining the effect of multiple and often competing familial contextual influences on adolescent bicultural competence development, this work provides insights on intergenerational cultural transmission and advances scholarship on the culturally bounded nature of human development.
In study 2, I offer a substantial extension to decades of family stress model research focused on how family environmental stressors may compromise parenting behaviors and youth development by testing a culturally informed family stress model. My model (a) incorporates family cultural and ecological stressors, (b) focuses on culturally salient parenting practices aimed to teach youth about the heritage culture (i.e., ethnic socialization), and (c) examines bicultural competence as a developmental outcome. Findings suggest that parents’ high exposure to ecological stressors do not compromise parental ethnic socialization or adolescent bicultural competence development. On the other hand, mothers’ exposures to enculturative stressors can disrupt maternal ethnic socialization, and in turn, undermine adolescents’ bicultural competence. By examining the influence of multiple family environmental stressors on culturally salient parenting practices, and their implications for adolescent bicultural competence development, this work provides insights on ethnic-racial minority and immigrant families’ adapting cultures and advances scholarship on the family stress model.
ContributorsSafa Pernett, Maria Dalal (Author) / White, Rebecca M. B. (Thesis advisor) / Knight, George P. (Committee member) / Updegraff, Kimberly A. (Committee member) / Wilkens, Natalie D. (Committee member) / Arizona State University (Publisher)
Created2019