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A Qualitative Case Study on the Factors that Impact Teacher Attrition and Retention in a Head Start Preschool Organization in New Jersey
No full textThis qualitative case study in a Head Start preschool in New Jersey explored the teacher attrition rates and teacher retention rates for the specific organization. The study looked at factors that impacted a Head Start teacher's decision to stay within the first five years of his or her employment. The study also explored the factors that impacted the retaining of teachers for more than five years past their employment. Improving teacher retention and decreasing teacher attrition rates is a long term goal of the organization. A case study design framework was applied to the research while exploring the factors that impact teacher attrition and retention rates. The study aimed to answer three main research questions: The questions were: How do teachers' perceptions of administration leadership styles relate to their overall decision to stay in their position at a Head Start preschool organization in New Jersey? How do administrators describe the factors that contribute to overall teacher attrition and retention at a Head Start preschool organization in New Jersey? How do teachers feel about their current working conditions, and what changes can be made to help improve teacher retention rates at a Head Start preschool organization in New Jersey? The study explored the perceptions of eight participants, consisting of six teacher participants and two center directors as it relates to teacher attrition and retention, and their feelings about their current work conditions, as well as what the participants identified as necessary to improve teacher retention rates within the organization. The teachers participated in either a focus group or one-on-one interview in order to learn about their experiences within the organization as it relates to attrition and retention. Using triangulation, this qualitative study drew conclusions using one-on-one teacher interviews, one-on-one director interviews, a teacher focus group, and member checks. Based on the findings and result of the study, it was concluded that many factors contributed to teacher attrition and retention within the organization. A few factors identified in the conclusion of the study were lack of administrative support, micromanagement, lack of trust, and unfair pay scales. Though changes can be made to current practices, further research is required to improve overall staff retention within the organization. Keywords: teacher attrition, teacher retention, leadership styles, administrative support, working environment, micromanagementEd.D., Educational Leadership and Management -- Drexel University, 201
A Global Study of Workplace Happiness of International Teaching Staff Members
No full textAn international teacher has a great impact on the direct teaching community, just as the community has a great impact on the teacher. This qualitative research study investigates the causes of workplace happiness for international teaching staff members and moments of immersed work activity, or "flow," within their teaching experience. The study aims to encourage awareness and reflection on the part of the educational institution to take actions to support their international staff members better. This study used a grounded theory approach, conducted through one-on-one, face-to-face interviews, as well as an online survey. Contact with study participants was made through digital platforms through the internet. The participants came from serval different global regions where international schools offering the International Baccalaureate (IB) or Advanced Placement (AP) curriculums were found. Through the coding process, the researcher drew out four major themes concerning the definition of happiness, positive work environments, positive student to teacher relationships, and autonomy in the workplace. Value theory, an understanding that when an international teacher feels valued by their teaching community, it encourages feelings of workplace happiness, emerged from these themes through the voice of participants. The study results led to recommendations by the researcher as to how international school institutions can better support international teacher staff members.Ed.D., Educational Leadership and Management -- Drexel University, 201
Associations of built and social neighborhood environment variables with pediatric BMI z-score and changes in BMI z-score
No full textIntroduction: Child obesity remains a major public health challenge and neighborhood environments could have a significant role in driving the epidemic. However existing evidence on the impact of neighborhoods on child obesity remains inconclusive. I conducted a systematic literature review of longitudinal studies analyzing the associations between built and social neighborhood environment exposures and pediatric weight. I also conducted a cross-sectional and longitudinal study of these exposures’ associations with BMI z-score using geographically linked electronic heath records (EHR) from a large sample of urban-dwelling, predominantly African American children. Methods: The literature search included six databases searched over 2011 to 2017. Thirty-one longitudinal studies met the inclusion criteria. Information on the study populations, exposure and outcome measures, and main results were extracted. To conduct the cross-sectional and longitudinal analyses I used a pediatric integrated EHR database of children residing in Philadelphia from 2007-2016. I used a generalized estimating equation to analyze the cross-sectional associations between built and social neighborhood environment variables with BMI z-score. I also examined synergisms between built and social environment variables. I used a fixed effects model to analyze the associations between a change in the neighborhood environment with a change in BMI z-score. In both analyses I examined whether associations were modified by age, sex, neighborhood SES, or population density. Results: Most longitudinal studies of the relationship between the built and social environment are prospective cohort studies conducted in high income western countries. The literature review showed that higher access to greenness, parks, and physical activity facilities were associated with less weight gain and lower obesity incidence. The literature also showed that increases in crime were associated with increases in BMI and higher obesity incidence. Cross-sectional analyses showed that higher greenness and Walk Score® were associated with lower BMI z-scores. Higher access to healthy food and physical activity facilities was associated with higher BMI z-scores. I did not find synergisms between built and social environment exposures. Longitudinal analyses showed that increases greenness and safety were associated with decreases in BMI z-score. The effects of safety were stronger in younger children than older children. Increases in social cohesion were associated with increases in BMI z-score and this effect was stronger in boys than in girls. Conclusions: Greenness and safety are associated with decreases in weight in children. Further research is needed to understand associations between changes in healthy food stores, physical activity facilities, urban form, and social cohesion with changes in pediatric BMI.Ph.D., Epidemiology -- Drexel University, 201
Understanding the Folding, Sorting, and Secretion of Neuroprotective Growth Factors
No full textProper folding is essential for protein function, while protein misfolding can lead to cellular dysfunction and disease and is thought to contribute to aging. Diseases of protein misfolding, collectively called conformational diseases, include neurodegenerative diseases, certain cancers, type II diabetes, and more. One shared characteristic of conformational diseases is toxic gain-of-function phenotypes caused by misfolded proteins. In neurodegenerative diseases, specifically, misfolded mutant proteins exert toxic gain-of-function phenotypes in only a specific subset of cells despite widespread or, in some cases, ubiquitous expression. In the first part of this dissertation, I investigated the mechanisms that make certain cells susceptible to misfolded proteins. To adequately address this question, I used a novel C. elegans neuroendocrine model with (1) a widely-expressed endogenous protein that has (2) a naturally-occurring mutation which causes misfolding and (3) an associated gain-of-function toxic phenotype in only a subset of cells that express this mutant protein. Using this model, I discovered that a misfolded insulin-like growth factor (IGF/DAF-28) protein exerts a specific “bystander effect” on an unrelated transforming growth factor beta (TGF-[beta]/DAF-7) protein. This bystander effect of misfolded IGF/DAF-28 on an innocent TGF-[beta]/DAF-7 causes cell-specific dysfunction in a sensory neuron, likely through competition for an ER chaperone on which the TGF-[beta]/DAF-7 protein is highly dependent for proper folding. Surprisingly, during this study, I observed opposing polarized localization of DAF-28/IGF and DAF-7/TGF-[beta] proteins within this single sensory neuron. As little is known about polarized sorting of soluble secreted proteins in neurons, in the second part of this dissertation, I investigated the differences in polarized sorting and secretion of DAF-28/IGF, DAF-7/TGF-[beta], and other soluble neuropeptides. My data point to existence of yet-uncharacterized pathways controlling the cellular localization and regulated secretion of these soluble IGF and TGF-[beta] growth factors that may help to better understand how proteins with almost identical functions are differentially regulated in the cell. Based on the neuroprotective roles of local secretion of IGF and TGF-[beta] proteins in the brain, my studies into the understanding mechanisms of DAF-28/IGF and DAF-7/TGF-[beta] biogenesis, sorting, and secretion not only advance the knowledge of basic growth factor biology but can also be used in future development of targeted therapeutic strategies for neurodegenerative diseases.Ph.D., Biological Sciences -- Drexel University, 201
Explaining Actual Causation via Reasoning about Actions and Change
No full textThe goal of this research is to investigate and demonstrate the suitability of action languages and answer set programming (ASP) to design and realize a novel framework for explaining actual causation. Actual causation is a broad term that encompasses all possible antecedents that have played a meaningful role in producing a consequence. Attempts to characterize reasoning about actual causation have largely pursued counterfactual analysis of a scenario, inspired by the intuition that if X caused Y, then not Y if not X. However, it has been widely documented that the counterfactual criteria alone is problematic and fails to recognize causation in a number of straightforward cases. Departing from a counterfactual reasoning approach, our framework favors reasoning about the underlying causal mechanisms of the scenario itself in order to explain how an outcome of interest came to be. The framework leverages techniques from Reasoning about Actions and Change to support reasoning about domains that change over time in response to a sequence of events. The action language AL enables us to represent a scenario in terms of the evolution of the state of the world over the course of the scenario's events. AL lends itself naturally to an automated translation in Answer Set Programming (ASP), using which, reasoning tasks of considerable complexity can be specified and executed. In this dissertation, we present a theoretical framework for reasoning about actual causation and demonstrate that the framework enables reasoning about traditionally challenging examples of actual cause. We also present a sound and complete implementation of the theoretical framework in ASP, along with a collection of empirical studies that evaluate and analyze the framework's performance on a number of novel and challenging problems.Ph.D., Computer Science -- Drexel University, 201
The Relationship Among Sport Type, Micronutrient Intake and Bone Mineral Density in an Athlete Population
No full textDiet and physical activity are two modifiable factors that can curtail the development of osteoporosis in the aging population. One purpose of this study was to assess the differences in dietary intake and bone mineral density (BMD) in a Masters athlete population (n=87, n=49 female; 41.06 ± 5.00 years of age) and examine sex- and sport-related differences in dietary and total calcium and vitamin K intake and BMD of the total body, lumbar spine, and dual femoral neck (TBBMD, LSBMD and DFBMD, respectively). Total calcium is defined as calcium intake from diet and supplements. Athletes were categorized as participating in an endurance or interval sport. BMD was measured using dual-energy X-ray absorptiometry (DXA). Data on dietary intake was collected from Block 2005 Food Frequency Questionnaires (FFQs). Dietary calcium, total calcium, or vitamin K intake did not differ between the female endurance and interval athletes. All three BMD sites were significantly different among the female endurance and interval athletes, with female interval athletes having higher BMD at each site (TBBMD: 1.26 ± 0.10 g/cm2, p<0.05; LSBMD: 1.37 ± 0.14 g/cm2, p<0.01; DFBMD: 1.11 ± 0.12 g/cm2, p<0.05, for female interval athletes; TBBMD: 1.19 ± 0.09 g/cm2; LSBMD: 1.23 ± 0.16 g/cm2; DFBMD: 1.04 ± 0.10 g/cm2, for female endurance athletes). Male interval athletes had higher BMD at all three sites (TBBMD 1.44 ± 0.11 g/cm2, p<0.05; LSBMD 1.42 ± 0.15 g/cm2, p=0.179; DFBMD 1.26 ± 0.14 g/cm2, p<0.01, for male interval athletes; TBBMD 1.33 ± 0.11 g/cm2; LSBMD 1.33 ± 0.17 g/cm2; DFBMD 1.10 ± 0.12 g/cm2 for male endurance athletes). Dietary calcium, total daily calcium and vitamin K intake did not differ between the male endurance and interval athletes. This study evaluated the relationship between calcium intake and BMD. No relationship between dietary or total calcium intake and BMD was evident in all female athletes, female endurance athletes or female interval athletes. In all male athletes, there was no significant correlation between dietary or total calcium intake and BMD at any of the measured sites. However, the male interval athlete group had a negative relationship between dietary calcium intake and TBBMD (r=-0.738, p<0.05) and LSBMD (r=-0.738, p<0.05). The negative relationship persisted between total calcium intake and LSBMD (r=-0.714, p<0.05), but not TBBMD, when calcium from supplements was included. The third purpose of this study was to evaluate the relationship between vitamin K intake (as phylloquinone) and BMD. In all female athletes, there was no significant correlation between vitamin K intake and BMD at any of the measured sites. No relationship between vitamin K and BMD was evident in female interval or female endurance athletes. Similarly, there was no relationship between vitamin K intake and BMD in the male endurance and interval groups. The final purpose of this study was to assess the relationship between the Calcium-to-Vitamin K (Ca:K) ratio and BMD. A linear regression model established that the ratio predicted TBBMD in female athletes, F(1,47) = 4.652, p <0.05, and the ratio accounted for 9% of the variability in TBBMD. The regression equation was: predicted TBBMD in a female athlete = 1.250 - 0.008 x (Ca:K). In conclusion, Masters interval athletes have higher BMD than Masters endurance athletes; however, neither dietary or supplemental calcium nor vitamin K were related to BMD in skeletal sites prone to fracture in older adulthood. We found that a Ca:K ratio could predict TBBMD in female athletes. Further research should consider the calcium-to-vitamin K relationship in conjunction with other modifiable, lifestyle factors associated with bone health in the investigation of methods to minimize the development and effect of osteoporosis in the older athlete population.M.S., Human Nutrition -- Drexel University, 201
Implications for Local Wetland Sustainability Based on the Autonomy of Airport-Operating Entities
No full textWetland ecosystems across the nation are declining in both abundance and viability. Often times such decline can be linked to airport management practices, with the autonomy of the corresponding airport-operating entity having implications for local wetland sustainability. This study sought to prove the link between such observed trends, examining four major airports built on or in close proximity to wetlands to see how autonomy impacted mitigation practices. Variables were established to determine the rank of autonomy and a case-by-case analysis of mitigation ensued to prove that there indeed was a link between airports and wetland health. Those airport-operating entities with the most autonomy showed minimal investment in wetland mitigation, either transferring liability to a third party or barely meeting federal and state requirements. While those less autonomous airport-operating entities seemed to go above and beyond mandated requirements, showing their commitment to local wetland sustainability and environmental stewardship.M.S., Environmental Policy -- Drexel University, 201
Flow Effects on Endothelial Cell Glucose Metabolism: Glycolytic Flux and O-GlcNAcylation in Health and Disease
No full textCardiovascular disease, the leading global cause of death, is precipitated by endothelial cell (EC) dysfunction. When EC are exposed to unidirectional steady laminar flow (>12 dynes/cm2 shear stress), the cells assume a healthy, quiescent phenotype in which EC phosphorylate endothelial nitric oxide synthase (eNOS) to produce NO, a vasodilator that is also important in preventing vascular disease. However, when EC fail to adapt to flow, for example in areas of oscillating disturbed flow, they have impaired NO production. Areas of disturbed flow are linked to EC dysfunction and diseases such as atherosclerosis. Endothelial metabolism has recently emerged as a powerful tool to regulate the vasculature. Both cancer cells and ECs generate the majority of their energy through glycolysis even in the presence of oxygen (the Warburg effect). When EC glucose metabolism was decreased by PFKFB3 blockade, EC proliferation, angiogenic sprouting, and cancer metastasis were inhibited both in vitro and in vivo. Endothelial metabolism also decreases in chronic laminar flow, which put EC in a quiescent state and decreased angiogenesis. Little is known about how different blood flow regimes regulate EC metabolism and how this could impact macrovascular disease. The goal of this research was to elucidate how hemodynamics regulate EC glucose metabolism, and how EC glucose metabolism can be modulated to restore EC function in disturbed flow. We hypothesized that steady laminar flow (shear stress of 20 dynes/cm2) but not oscillating disturbed flow (shear stress of 4±6 dynes/cm2) reduces glycolytic flux and eNOS O-GlcNAcylation to promote a healthy endothelial phenotype. First, I adapted human EC to steady laminar and oscillating disturbed flow in a cone-and-plate device in vitro and quantified changes in (1) endothelial glycolytic activity and (2) eNOS O-GlcNAcylation. Stable isotope mass spectrometry and YSI Bioanalysis revealed an overall decrease in glucose uptake and glycolytic activity in EC exposed to steady laminar but not oscillating disturbed flow. HUVEC exposed to oscillating disturbed flow had over two times more glucose consumption compared to cells exposed to steady laminar flow. Glycolytic intermediate total pool sizes such as fructose-1,6-bisphosphate, 1,3-bisphosphoglyercate, and phosphoenolpyruvate were 60-70% lower in HUVEC exposed to steady laminar flow compared to cells exposed to oscillating disturbed flow. Next, I showed that eNOS O-GlcNAcylation was abolished in EC exposed to steady laminar (~75% lower) but not oscillating disturbed flow. Interestingly, there was no change in protein level, localization, or activity of key O-GlcNAcylation enzymes (OGT, OGA, or GFAT). Instead, glycolysis inhibition via 2-deoxy-2-glucose (2-DG) in cells exposed to disturbed flow efficiently decreased eNOS O-GlcNAcylation by 60%, thereby increasing eNOS phosphorylation by 20% and NO production by 65%. Finally, I investigated altered glucose metabolism in pulmonary arterial hypertension (PAH). Human pulmonary artery EC from PAH patients showed three times as much glucose uptake as healthy patients. Additionally, glycolytic intermediates such as fructose-1-6, bisphosphate and 3-phosphoglycerate showed 50-75% higher total pool levels in PAH patients compared to healthy patients. Furthermore, PAH patients showed reduced eNOS O-GlcNAcylation and NO bioavailability. My data demonstrate that steady laminar but not oscillating disturbed flow decreases glycolytic activity as well as HBP activity. Specifically, glycolytic flux controls eNOS O-GlcNAcylation and UDP-GlcNAc substrate availability, thus impacting eNOS phosphorylation and NO production. This research shows for the first time that O-GlcNAcylation is regulated by mechanical stimuli; relates flow-induced glycolytic flux changes to macrovascular disease; and highlights O-GlcNAcylation as a novel therapeutic target to restore eNOS activity and to prevent EC dysfunction in cardiovascular disease.Ph.D., Biomedical Engineering -- Drexel University, 201
Computational Models of Endothelial Cell Growth Factor Kinetics and Glucose Metabolism
No full textCardiovascular disease (CVD) is the leading cause of death worldwide, and endothelial dysfunction contributes to CVD progression. While experimental studies attribute endothelial dysfunction to changes in cell signaling, protein expression, and metabolism, it remains unclear how these individual changes interact within the complex endothelium to lead to the dysfunctional phenotype. Computational models provide an essential tool to understand the endothelium as a system. The dissertation objective was to use mass action kinetics and stoichiometric computational models to predict endothelial growth factor binding and glucose metabolic flux. I first created a mass action kinetics model to investigate fibroblast growth factor-2 (FGF2) binding to endothelial cells under laminar flow by incorporating flow-induced changes to the endothelial cell apical surface. FGF2 model dynamics were described by a set of ordinary differential equations and kinetic parameters from the literature. When the model included increased heparan sulfate proteoglycan production and binding site availability with shear stress, as well as increased FGF2 dissociation with shear stress, the model successfully predicted FGF2 biphasic binding response as a function of shear stress. Next, I created a carbon transition model to predict endothelial cell intracellular metabolic fluxes using isotope labeling experiments. The model traces carbon movement through glycolysis, the pentose phosphate pathway and the TCA cycle. The model was iteratively updated to reduce the error between the predicted and measured experimental data. The final model highlighted the importance of glutamine in reproducing TCA cycle intermediates and in feeding back into glycolysis. Finally, I developed a stoichiometric endothelial model to describe the metabolic state of a quiescent endothelial cell in vitro. A genome scale cell model was curated into an endothelial-specific model using publicly available transcriptomic data to remove reactions associated with proteins that were not expressed in endothelial cells. The carbon transition model fluxes were used to constrain the minimum and maximum fluxes in the stoichiometric endothelial model. I then used the model to explore possible endothelial metabolic objective functions, including minimizing oxidative stress or resource consumption. I concluded that no single metabolic objective function accurately predicted quiescent endothelial monolayer metabolism. Together these models provide valuable insight into FGF2 binding kinetics and steady state metabolic endothelial cell objectives. In addition, the mass action kinetic and stoichiometric endothelial models provide a systems-level analysis of endothelial function, enhancing our understanding of the complex interactions that contribute to endothelial dysfunction and eventual cardiovascular disease.Ph.D., Biomedical Engineering -- Drexel University, 201
The Role of Dance/Movement Therapy in the Treatment of Negative Syndrome and Psychosocial Functioning of Patients with Schizophrenia: A Pilot Study
No full textOptimizing psychosocial functioning and overall well-being by reducing the severity of negative symptoms are important outcomes for individuals with schizophrenia. Movement-based therapeutic approaches are uniquely capable of addressing the non-verbal nature of negative symptoms. Dance/movement therapy, a promising treatment for mental health conditions such as schizophrenia, has been found to reduce the occurrence and severity of negative symptoms and have a positive impact on psychosocial functioning. Although preliminary findings suggest dance/movement therapy as a treatment intervention, limited research and inconclusive findings preclude generalizations and more research is needed. This pilot's study overall goal was to determine if dance/movement therapy intervention is effective in the treatment of negative symptoms and psychosocial functioning in individuals with schizophrenia. Specific aims were: (1) to examine the effects of a 10-week group dance/movement treatment program on negative symptoms in schizophrenia, (2) to gain greater understanding of participants' perceptions of the intervention, (3) to use participants' feedback of the intervention to better understand its impact, and (4) to examine the feasibility of the treatment procedures and research protocol. This pilot study employed a mixed methods intervention design with explanatory intent, in which a randomized controlled trial was followed by semi-structured exit interviews. Participants, severely ill individuals diagnosed with schizophrenia (N = 31), were randomized to two conditions: Dance/Movement Therapy and Treatment as Usual groups using simple randomization method. Participants reported on negative symptoms and psychosocial functioning outcomes prior to and after the program. Qualitative semi-structured exit interviews were conducted with participants who attended at least 50% of the dance/movement therapy sessions (n = 15). The quantitative data showed no improvement of outcomes in the DMT condition. The qualitative data suggests that treatment resulted in enhanced interpersonal connectivity, self-integration, emotional support, symptoms management and had physical impact on participants. The study feasibility findings also suggest that study procedures were feasible at this setting and that treatment was well accepted by the participants. These findings suggest that manualized DMT treatment protocol specifically developed for this study was successfully implemented and could be easily implemented in a larger, multi-site, clinical trial allowing for study replication. The findings of this study contribute to knowledge about body-based interventions for schizophrenia. The current lack of clear evidence for the efficacy of dance/movement therapy in reduction of severity of negative symptoms and improvement of psychosocial functioning redirects thinking about methodological facets of both research and practice.Ph.D., Creative Arts in Therapy -- Drexel University, 201