Matching Items (43,913)
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
This thesis deals with the analysis of interpersonal communication dynamics in online social networks and social media. Our central hypothesis is that communication dynamics between individuals manifest themselves via three key aspects: the information that is the content of communication, the social engagement i.e. the sociological framework emergent of the communication process, and the channel i.e. the media via which communication takes place. Communication dynamics have been of interest to researchers from multi-faceted domains over the past several decades. However, today we are faced with several modern capabilities encompassing a host of social media websites. These sites feature variegated interactional affordances, ranging from blogging, micro-blogging, sharing media elements as well as a rich set of social actions such as tagging, voting, commenting and so on. Consequently, these communication tools have begun to redefine the ways in which we exchange information, our modes of social engagement, and mechanisms of how the media characteristics impact our interactional behavior. The outcomes of this research are manifold. We present our contributions in three parts, corresponding to the three key organizing ideas. First, we have observed that user context is key to characterizing communication between a pair of individuals. However interestingly, the probability of future communication seems to be more sensitive to the context compared to the delay, which appears to be rather habitual. Further, we observe that diffusion of social actions in a network can be indicative of future information cascades; that might be attributed to social influence or homophily depending on the nature of the social action. Second, we have observed that different modes of social engagement lead to evolution of groups that have considerable predictive capability in characterizing external-world temporal occurrences, such as stock market dynamics as well as collective political sentiments. Finally, characterization of communication on rich media sites have shown that conversations that are deemed "interesting" appear to have consequential impact on the properties of the social network they are associated with: in terms of degree of participation of the individuals in future conversations, thematic diffusion as well as emergent cohesiveness in activity among the concerned participants in the network. Based on all these outcomes, we believe that this research can make significant contribution into a better understanding of how we communicate online and how it is redefining our collective sociological behavior.
ContributorsDe Choudhury, Munmun (Author) / Sundaram, Hari (Thesis advisor) / Candan, K. Selcuk (Committee member) / Liu, Huan (Committee member) / Watts, Duncan J. (Committee member) / Seligmann, Doree D. (Committee member) / Arizona State University (Publisher)
Created2011
Description
Drawing on a wide variety of literature from social constructionism, communities of practice and knowledge management this study brings to light the kind of support teachers will need in order to be able to use a knowledge construction model to develop a continual learning process for arts integration. Arts integration is a highly effective instructional strategy that brings active engagement, problem solving and higher levels of cognition to students. However arts integration is not easy work. It takes a great deal of planning and collaboration. In this action research study, I take the perspective of a social artist, a facilitator, who offers a framework for a group of teacher participants to dialogue, collaborate and share ideas and skills to develop arts integrated products to share with others. Utilizing a mixed methodology approach, the findings of this action research study revealed that the intervention had a positive impact on the participants. Though there were some set backs, participants reported more dialogue and shared experiences about arts integration on a daily basis, more dialogue about new arts integrate ideas, and an increased sense of collaboration in developing arts integrated products. Furthermore, the Knowledge Construction Model (KCM) concept had strength as a potential professional development model for teachers and schools interested in growing their arts integration practices.
ContributorsBenson, Robert Jason (Author) / Beardsley, Audrey (Thesis advisor) / Serafini, Frank (Committee member) / Santarelli, Denton (Committee member) / Arizona State University (Publisher)
Created2011
Description
This research addresses the ability for neighborhoods to assess resiliency as it applies to their respective local areas. Two demographically and economically contrasting neighborhoods in Glendale, Arizona were studied to understand what residents' value and how those values link to key principles of resiliency. Through this exploratory research, a community-focused process was created to use these values in order to link them to key principles of resiliency and potential measureable indicators. A literature review was conducted to first assess definitions and key principles of resiliency. Second, it explored cases of neighborhoods or communities that faced a pressure or disaster and responded resiliently based on these general principles. Each case study demonstrated that resiliency at the neighborhood level was important to its ability to survive its respective pressure and emerge stronger. The Heart of Glendale and Thunderbird Palms were the two neighborhoods chosen to test the ability to operationalize neighborhood resiliency in the form of indicators. First, an in-depth interview was conducted with a neighborhood expert to understand each area's strengths and weaknesses and get a context for the neighborhood and how it has developed. Second, a visioning session was conducted with each neighborhood consisting of seven participants to discuss its values and how they relate to key principles of resiliency. The values were analyzed and used to shape locally relevant indicators. The results of this study found that the process of identifying participants' values and linking them to key principles of resiliency is a viable methodology for measuring neighborhood resiliency. It also found that indicators and values differed between the Heart of Glendale, a more economically vulnerable yet ethnically diverse area, than Thunderbird Palms, a more racially homogenous, middle income neighborhood. The Heart of Glendale valued the development of social capital more than Thunderbird Palms which placed a higher value on the condition of the built environment as a vehicle for stimulating vibrancy and resiliency in the neighborhood. However, both neighborhoods highly valued public education and providing opportunities for children to be future leaders in their local communities.
ContributorsAcevedo, Shannon (Author) / Pijawka, K. David (Thesis advisor) / Phillips, Rhonda (Committee member) / Lara-Valencia, Francisco (Committee member) / Arizona State University (Publisher)
Created2011
Description
Coal bed natural gas (CBNG) production has become a significant contribution to the nation's energy supply. Large volumes of water are generated as a byproduct of CBNG extraction, of which this "product water" is relatively high in sodium. High sodicity reduces water quality and limits environmentally compliant disposal options for producers. Crop irrigation with CBNG product water complies with state and federal laws and is a disposal method that also provides a beneficial use to private landowners. However, this disposal method typically requires gypsum and sulfur soil amendments due to the high levels of sodium in the water, which can reduce soil infiltration and hydraulic conductivity. In this study, I tested a new product called Salt Extractor that was marketed to CBNG producers to ameliorate the negative effects of high sodicity. The experiment was conducted in the Powder River Basin of Wyoming. I used a random block design to compare the soil and vegetation properties of plots following application with CBNG product water and treatments of either Salt Extractor, gypsum and sulfur (conventional), or no treatment (control). Data was analyzed by comparing the amount of change between treatments after watering. Results demonstrated the known ability of gypsum and sulfur to lower the relative sodicity of the soil. Plots treated with Salt Extractor, however, did not improve relative levels of sodicity and exhibited no favorable benefits to vegetation.
ContributorsAdams, Shelly (Author) / Hall, Sharon (Thesis advisor) / Chew, Matt (Committee member) / Stromberg, Juliet (Committee member) / Arizona State University (Publisher)
Created2011
Description
Many studies have shown that access to healthy food in the US is unevenly distributed and that supermarkets and other fresh food retailers are less likely to be located in low-income minority communities, where convenience and dollar stores are more prevalent grocery options. I formed a partnership with Phoenix Revitalization Corporation, a local community development organization engaged in Central City South, Phoenix, to enhance the community's capacity to meet its community health goals by improving access to healthy food. I used a community-based participatory approach that blended qualitative and quantitative elements to accommodate collaboration between both academic and non-academic partners. Utilizing stakeholder interviews, Nutrition Environment Measures Surveys (NEMS), and mapping to analyze the community's food resources, research revealed that the community lacks adequate access to affordable, nutritious food. Community food stores (n=14) scored an average of 10.9 out of a possible 54 points using the NEMS scoring protocol. The community food assessment is an essential step in improving access to healthy food for CCS residents and provides a baseline for tracking progress to improve residents' food access. Recommendations were drafted by the research partnership to equip and empower the community with strategic, community-specific interventions based on the research findings.
ContributorsCrouch, Carolyn (Author) / Harlan, Sharon (Thesis advisor) / Eakin, Hallie (Committee member) / Aftandilian, David (Committee member) / Arizona State University (Publisher)
Created2011
Description
Dating violence in ethnic minority populations is an understudied phenomenon and little attention has been paid to the experiences of Mexican American youth; less research has been done on how those experiences alter perceptions and acceptance of participation in prevention programs. This study advances knowledge on how Mexican American adolescents view dating violence prevention programs and how cultural beliefs and values may hinder or encourage effective participation. Focus groups (N = 9) were form with Mexican American youth aged 15-17 years separated by gender and acculturation status (Mexican Oriented/Bicultural/Anglo Oriented), as determined previously by acculturation scores measured by the Acculturation Rating Scale for Mexican Americans (ARMSA; 0 or below = Mexican Oriented, 0-1 = Bicultural, 1 or above = Anglo Oriented). Several themes emerged throughout the focus group discussions that were derived from culturally-based needs. Mexican American adolescents made recommendations for program development (e.g., a broad curriculum beyond the topic of dating violence) and delivery (e.g., barriers to participation, the implications of peer involvement) within the context of their cultural values and needs. Low acculturated and bicultural teens identified specific cultural needs and their relevance within a dating violence prevention program. However, across all groups, adolescents felt that the needs of Mexican American youth were similar to other youth in regards to dating violence prevention programs. Implications for how social work can best design and implement prevention programs for Mexican American adolescents are discussed.
ContributorsAltamirano, Bianca (Author) / Williams, Lela R (Thesis advisor) / Ayón, Cecilia (Committee member) / Marsiglia, Flavio F (Committee member) / Arizona State University (Publisher)
Created2011
Description
Though police-involved homicides have generated controversy and caused community disruptions and riots for many years, few efforts to systematically capture and study these events exist. The lack of research on arrest-related deaths (ARDs) is particularly troubling not only because of the consequences of these events, but also because the nature of how these deaths occur may also be changing. In particular, recent attention has shifted away from incidents where police use firearms to incidents where other less-lethal tools are used but death still occurs (e.g., TASERs). In 2000, the Federal Government sought to address this problem through the creation of the Deaths in Custody Reporting Program (DCRP), a national-level voluntary reporting system managed by the Bureau of Justice Statistics. There have been few efforts, however, that have assessed the accuracy and completeness of the DCRP data collection. The current study seeks to accomplish this through a comparison of ARDs in the DCRP to open-source, web-based media reports of ARDs in a stratified, random sample of 12 states during 2005. The study finds that all types of ARDs, not just police-involved homicides, are not accurately and reliably reported. Furthermore, the information provided is not reliably reported or interesting to research initiatives. Improvements in how the data is collected and what type of data is collected are needed. This adds to the scholarly research that advocates for a systematic and reliable national dataset of all deaths that occur in the process of arrest.
ContributorsBorrego, Andrea (Author) / White, Michael D. (Thesis advisor) / Kane, Robert (Committee member) / Fornango, Robert (Committee member) / Arizona State University (Publisher)
Created2011
Description
A collection of short stories, each told with a differing narrative structure and a different cast of characters. Some stories in the collection employ traditional narrative structures such as the frame tale and the three-act structure. Other stories borrow their structures from society at large, the bombardment of text and media Americans face every day (letters, recipes, song lyrics). The stories explore how people can read our world and possibly interpret larger shared narrative strands. These stories focus attention on human responses to illness, loss, family, war and protest, looking for opportunities to expand recognition of the range of emotions, moving beyond generic understanding to personal connection. The tone of the collection tends towards dark humor to hint at the deeper, possibly inexplicable human condition.
ContributorsBlickle, Benjamin (Author) / Turchi, Peter (Thesis advisor) / McNally, Mike (Committee member) / Pritchard, Melissa (Committee member) / Arizona State University (Publisher)
Created2011
Description
Responding to the allegedly biased research reports issued by large investment banks, the Global Research Analyst Settlement and related regulations went to great lengths to weaken the conflicts of interest faced by investment bank analysts. In this paper, I investigate the effects of these changes on small and large investor confidence and on trading profitability. Specifically, I examine abnormal trading volumes generated by small and large investors in response to security analyst recommendations and the resulting abnormal market returns generated. I find an overall increase in investor confidence in the post-regulation period relative to the pre-regulation period consistent with a reduction in existing conflicts of interest. The change in confidence observed is particularly striking for small traders. I also find that small trader profitability has increased in the post-regulation period relative to the pre-regulation period whereas that for large traders has decreased. These results are consistent with the Securities and Exchange Commission's primary mission to protect small investors and maintain the integrity of the securities markets.
ContributorsDong, Xiaobo (Author) / Mikhail, Michael (Thesis advisor) / Hwang, Yuhchang (Committee member) / Hugon, Artur J (Committee member) / Arizona State University (Publisher)
Created2011