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Gestational Diabetes, Ethnicity, and Diet among low-income women in Philadelphia
No full textM.P.H., Community Health and Prevention -- Drexel University, 201
Tools for the analysis of B-cell clonal diversity in immune repertoires
Get PDFThe lymphocytes of an organism harbor a diverse collection or repertoire of antigen receptors (antibodies (Ab) on B cells and T cell receptors (TCR) on T cells). This diversity of the adaptive immune repertoire is important for effective immune defense. In my thesis, I have developed computational methods to study the diversity and landscape of the immune repertoire using data from next-generation sequencing experiments and have applied these tools to the study human B cells in the blood and in different tissues. The first tool I developed was an efficient and accurate means of identifying the nearest germline-encoded variable (V) region gene in Ab and TCR rearrangements using anchoring sequences. I used this method to demonstrate that the length of the V gene sequence and its level of somatic mutation influenced the reliability of V gene assignment. Only with adequate V gene assignment can closely related sequences be reliably grouped together into clones (i.e. sequences from lymphocytes that likely derive from a common progenitor cell). With this method, I contributed to a computational pipeline that can process millions of antibody or TCR sequences in hours to days, unlike earlier methods. I used this method to identify and track expanded B-cell clones through the human body, creating an atlas of clonal connections between the blood, bone marrow, spleen, lung, mesenteric lymph node, jejunum, ileum and colon. To power the analysis to study clonal overlap between the tissues, I performed rarefaction analysis on biological replicates to determine how many replicates and how large the clones needed to be to have confidence in clones being present or absent in the different tissue sites. To quantify the level of overlap between two-tissue sites, I used the cosine statistic and showed that my analysis was robust to different measures of clones and clone size. To visualize the tissue distribution of large clones, I created line-circle plots, in which clones are displayed as lines with circles corresponding to the tissues. The sizes of the tissue circles were proportional to clone copy numbers and the colored wedges within the circles indicated the fraction of sequencing libraries that contained sequences from the clone. My analysis revealed the clones tended to partition into two large networks in the human body, one in blood-rich tissues such as the bone marrow, spleen and lung, and another network that was more separated from the blood, in the gastrointestinal tract. I also used methods to visualize and characterize the diversification within B-cell clones due to somatic hypermutation, including lineage tree analysis, the analysis of four-fold silent mutations (mutations that do not change the amino acid sequence), methods for studying intermingling of lineage tree branches (clumpiness) and the use of Bayesian modeling approaches. I used these methods to show that GI tract clones in the human body harbor higher levels of somatic hypermutation and that there is extensive sharing of sequence variants within individual clonal lineages between different sites within the GI tract. Finally, I studied selection of mutations within clonal lineages over time in patients with an autoimmune disease (Sjogren's syndrome) and showed that large clones that were resistant to B-cell depletion therapy were under negative selection. Together, my analysis tools provide a useful means to systematically and quantitatively characterize diversity at the population (repertoire) level and at the clonal level. These tools can be applied to future immune repertoire profiling to study immune responses to vaccines, cancer and infectious disease.Ph.D., Biomedical Science -- Drexel University, 201
Agency Informing Techniques in Interactive Narratives
No full textWithin interactive narrative research, agency is commonly focused on the player’s autonomy within a game. However agency can be divided into two central components. A player’s autonomy, defined as theoretical agency, is the first component. Agency also covers the feeling of satisfaction from seeing the results an action; this is known as perceived agency. Currently, researchers frequently investigate methods for increasing theoretical agency as the primary method of increasing perceived agency. Yet games often employ many techniques that affect perceived agency without affecting theoretical agency. We define such a technique as an Agency Informing Technique (AIT). Our research presents a taxonomy of AITs based on contemporary narrative games and perceived agency related research. This taxonomy allows for better understanding of how game mechanics affect a player’s perceived agency over time. We use this taxonomy to investigate a new experimental interactive narrative that shows how AITs can be used when designing a narrative. This experimental game focuses on informing players of possible future outcomes while they are making a decision. We find that our taxonomy of AITs can help explain how players can understand potential future outcomes in an interactive narrative when combined with strong environmental and narrative cues.M.S., Digital Media -- Drexel University, 201
Defining the Molecular Pathways Involved in CXCL12-mediated Rescue of Dendritic Spines and Cognitive Deficits in an Animal Model of neuroHIV
No full textDespite the introduction of antiretroviral therapy (ART), approximately 50% of HIV+ patients still experience some degree of neurological dysfunction. The loss of dendritic spines, the main sites of excitatory input on neurons, is a pathological hallmark of HIV-associated neurocognitive disorders (HAND). The chemokine-receptor pair, CXCL12/CXCR4, is essential for numerous homeostatic processes in the CNS, including neurotransmission, pro-survival signaling, and neuronal-glial interactions. Recently, our laboratory demonstrated that CXCL12 increases dendritic spine number on cortical neurons, though the mechanism modulating this effect is not known. Since CXCL12/CXCR4 signaling plays a critical role in maintaining homeostasis in the CNS and this chemokine-receptor pair is known to be dysfunctional during HAND, restoration of this signaling axis may ameliorate cognitive deficits in HIV+ individuals. Our mechanistic studies in cultured primary rat cortical neurons revealed that CXCL12 depends on the activation of Rac1 and its downstream mediators (PAK1, LIMK1, SSH1, and cofilin) to modulate dendritic spine density. Furthermore, exposure to CXCL12 resulted in functional changes in actin polymerization as assessed by the F-actin to G-actin ratio. CXCL12 upregulated spine number through a specific increase in thin spines, which are associated with learning and plasticity. We extended these mechanistic studies to intact wild-type (WT) animals and showed that exogenous CXCL12 treatment can alter dendritic spine density and morphology in the medial prefrontal cortex (mPFC) in layer II/III pyramidal neurons; this effect, as observed in vitro, depended on Rac1 activation. The therapeutic potential of restoring or enhancing CXCL12/CXCR4 signaling has not been previously explored. We first demonstrated that HIV-Tg rats, a rodent model of neuroinflammation and HAND, are specifically deficient in attentional set-shifting and this was associated with a reduction in dendritic spine density in layer II/III pyramidal neurons. Once a day intracebroventricular (ICV) administration of CXCL12 completely rescued dendritic spine loss and cognitive dysfunction in HIV-Tg rats. As seen in WT rats, the chemokine specifically increased the number of thin dendritic spines in layer II/III pyramidal neurons of the mPFC. In the same animals, the upregulation of spine density was significantly correlated with an improvement in cognitive flexibility, a task mediated exclusively by the mPFC. Therefore, exogenous CXCL12 completely restored both structural and functional deficits in the HIV-Tg rat, even after dysfunction was already present. Overall, these data suggest that targeting neuronal CXCL12/CXCR4 signaling may represent a valid strategy for neurorestorative therapies for HAND and other diseases characterized by spine loss, such as schizophrenia and Alzheimer’s disease.Ph.D., Pharmacology and Physiology -- Drexel University, 201
An Examination of the Relationship Between Level of Job Satisfaction and Intention to Remain in the Profession Among Special Education Teachers in Two Small City Settings
No full textSpecial educator teacher attrition has been an ongoing issue in the U.S. for decades. Urban districts face particular challenges with special educator teacher attrition due to high poverty rates and limited resources. Current research indicates that many factors contribute to the high rates of special educator attrition in urban areas, but there is limited information regarding the extent of the role job satisfaction plays in special educator teacher retention. Understanding the extent of this relationship enables district leaders to make informed decisions regarding additional supports that may be necessary to improve special educator retention. The purpose of this quantitative, correlational, explanatory research was to examine the relationship between urban special educators' level of job satisfaction and their intention to remain in their current positions. The central Research Question guiding this study was: What is the relationship between job satisfaction among special educators in two small cities and their intention to remain in their current teaching position? This research was grounded in both Herzberg's motivational and hygiene theory and Maslow's needs hierarchy theory. The researcher used both purposeful and snowball sampling to identify special educators in targeted small city districts in two counties within the same U.S. east coast region. A cross-sectional survey design was used to obtain current information regarding job satisfaction and teachers' intentions to remain in their current position. Data were analyzed using SPSS software to conduct a correlational analysis between the level of small city special educators' job satisfaction and their intention to remain in their current position. Results of the survey indicated that though the majority of participants reported high levels of job satisfaction, an equally high percentage planned to pursue employment outside of their current district. These data have the potential benefit district administrators who are interested in better supporting and retaining special educators, however it is evident that additional research is needed to better understand the factors motivating special educators to leave their positions.Ed.D., Educational Leadership and Management -- Drexel University, 201
Incivility in the Workplace: A Phenomenological Study Conducted in Northern California
No full textThe purpose of this qualitative, phenomenological study was to explore the essence of the lived experiences of individuals who self-identified as having experienced workplace incivility in corporate settings and to understand how their experiences affected them on personal and professional levels. This research gained not only the perspective of those individuals who self-identified as being on the receiving end of workplace incivility, known as "targets, but also those who initiated incivility in the workplace--individuals known as "instigators"--and those who were spectators to incivility being done to others, called "observers." Prior research shows over the last couple of decades, workplace incivility has increased and continues to worsen (Pearson & Porath, 2005) with nearly all employees having indicated they have been on the receiving end of incivility and or having directly witnessed it (Porath & Pearson, 2010). Of the 15 individuals who participated in this research, 12 were female and three were male. The participants worked in the Human Resources field in diverse organizations and in various locations throughout Northern California. Three research questions guided this research study: (a) What workplace incivility behaviors do employees experience in organizations? (b) How do employees respond to various forms of workplace incivility? and (c) What are the antecedents and consequences of workplace incivility? The findings identified that (a) workplace incivility continues to thrive in the work environment, (b) workplace incivility has negative consequences, (c) responses to workplace incivility by organizations can vary, and (d) Human Resources employees many times have no one to turn to when they find themselves as targets. More research is needed to determine how best to make organizations aware that workplace incivility is alive and thriving and can have detrimental effects not only upon the organization, but its employees. In addition, companies need to be trained on how best to deal with workplace incivility and implement strategies to best address the phenomenon. Lastly, further research is warranted to determine if emotional intelligence can help organizations, in particular leaders, effectively deal with workplace incivility.Ed.D., Educational Leadership and Management -- Drexel University, 201
For Whom the Quotas Count: Negotiating Blackness in Brazilian Higher Education
No full textAffirmative action was employed in 2002 to increase access to the elite system of Brazilian higher education. This policy, deemed constitutional by Brazil's Supreme Court in 2012, supports the use of reserved spaces for underrepresented students based on race, ethnicity, class, ability, public school attendance, and for children of officers killed in the line of duty. The race-based quota system has allowed more Black students to attend quality universities, however, at what expense? Race continues to be a complex issue in Brazil where more than half of its citizens identify as non-White. As a result, this complicates understandings of race in general and who should benefit from quotas in particular. Using a critical ethnographic design, this study examines how self identified Black university students negotiate race, their status as quota students, and other identities under a policy mandated to ensure opportunity on one hand, within institutional environments that restrict opportunity on the other. Conceptually grounded in critical race theory and intersectionality, this research centers race as a unit of analysis that when compounded by the existence of other identities, creates particular outcomes and experiences in educational spaces. Findings from interviews, observations, and critical discourse analysis reveal that Black students proactively manage their identities despite institutional challenges. Although Brazil provides the setting for this dissertation, it serves as one case in the larger global context of addressing the complex relationship between universities, underrepresented students, and policies that sometimes miss the mark when confronting issues of equity.Ph.D., Education -- Drexel University, 201
Music Therapy and Restorative Justice: Overcoming Risk to Fulfill the Promise of Urban Youth
No full textChildren and adolescents living in poor, urban environments are often exposed higher rates of trauma, abuse, and neglect compared to their middle- and upper-class counterparts. These youth have traditionally been referred to as "at-risk" in reference to the increased risk of poor mental health, poverty, crime, and death. Alternatively, this population can be referred to as "at-promise" to acknowledge the potential for resilience and to break the cycle of poverty. This critical review of the literature focuses on the role of incarceration and poor mental health in the perpetuation of the cycle of poverty. The Restorative Justice Model is discussed as a framework for rehabilitative programs that aim to hold criminal offenders accountable for their actions, address the issues that caused them to offend in the first place, and protect and heal the community. The use of music therapy with at-promise youth is also discussed for its role in promoting safe self-expression and decreasing symptoms of depression and anxiety. Suggestions are made for the integration of music therapy practices within the Restorative Justice Model in an attempt to alleviate the cyclical impact of urban poverty on at-promise youth.M.A., Music Therapy and Counseling -- Drexel University, 201
Trust the Process: Exploring the Integration of Sports in Dance/Movement Therapy with Adolescents
No full textThe purpose of this project is to develop a method for therapy for adolescents in a school setting. Relevant literature and research is reviewed to inform the development and implementation of the method. The literature review includes information regarding dance/movement therapy and sports, specifically for the adolescent population with diagnoses such as autism spectrum disorders and specific learning disorders. The method integrates sports and dance/movement therapy in a therapeutic approach designed for adolescent students. Concepts such as competition and creativity are addressed through descriptive case vignettes. The method is intended to provide structure through the use of sports-based activities in dance/movement therapy for adolescents. The author offers reflections on how the literature and research informed the method, limitations and recommendations for the method, and the influence that this work had on the author as an emerging dance/movement therapist.M.A., Dance/Movement Therapy and Counseling -- Drexel University, 201
Assessing the Impact of Climate and Land Use Change on Water Resources in Schuylkill River Watershed
No full textThe Schuylkill River watershed located in southeastern Pennsylvania caters to various services including supplying drinking water to the cities, providing water for power generation, recreation, transportation, irrigation, and supporting ecosystems. Changing climate and land use patterns are likely to impact the water resources by influencing precipitation, evapotranspiration, soil moisture, and infiltration rates at a local scale. This study attempts to build a hydrologic model to assess the impact of climate and land use change on water resources in the region. The hydrologic model was created within the STELLA modeling environment. The STELLA model was calibrated for three years, from 2007 to 2010, by comparing daily recorded stream flow with the model prediction for stream flow. Downscaled future climate change scenarios were gathered from the Localized Constructed Analogs (LOCA) from 2020 to 2040 for the Representative Concentration Pathways (RCP) 4.5 and RCP 8.5 emission scenarios. Three regional land use change scenarios were developed based on historical land use and land cover change trends. The calibrated STELLA model was then run under projected climate and land use scenarios to analyze the effect of those changes on water resources. Results of these simulations indicate that daily streamflow objectives are met 67.68% -76.85% of the time for the time period between 2040-2040 under the RCP 4.5 emission scenarios, and 67.17% - 75.55% of the days under the RCP 8.5 emission scenarios in the Schuylkill River watershed. The impact of land use and land cover change on water resources was found to be insignificant for this region.M.S., Environmental Engineering -- Drexel University, 201