16484 research outputs found
Sort by
Understanding the Adolescent Experience of Mental Health Stigma: A Pilot Study
No full textThe purpose of this study was to understand the experiences of adolescents with mental illness and how they have encountered stigma. It is important for mental health clinicians to understand the ways stigma are experienced by adolescents, because most mental illness diagnoses become apparent during this time; however, many do not seek treatment. In this pilot study, two female adults were interviewed about their experiences as adolescents with mental illness and how these experiences have affected them in their present lives. Clinical implications include encouraging autonomy within an adolescent’s treatment, offering psychoeducation for family, and promoting empowerment and success in art therapy.M.A., Art Therapy and Counseling -- Drexel University, 201
Catheter Associated Urinary Tract Infection Reduction Strategy: Nurse Leader Rounds
No full textBackground: Hospital acquired catheter associated urinary tract infections (CAUTI) remain a problem contributing to death or extension of illnesses in patients in intensive care units each year. Rounding by staff and nurse leaders has been successful in increasing patient satisfaction and safety in hospitalized patients. The National Healthcare Safety Network reports that urinary tract infections are the most commonly occurring infection in critical care patients. Current efforts to reduce CAUTI are widely studied and only partially successful. Purpose: The purpose is to decrease CAUTI incidence by decreasing device utilization in five intensive care units in a suburban health system. Methods: Two questions focused on catheter removal were incorporated into the hardwired nurse leader rounds. Implementation Plan/Procedure: Using Rounds+ (TM), the added questions were loaded and deployed for ICU patients with indwelling urinary catheters for a period of 3 weeks. Implications/Conclusion: Although the device days did not decrease, multiple opportunities to use the nurse driven protocol were identified. Additionally, the greatest reason for maintaining the catheter was captured as strict intake and output measurement. Keywords: catheter associated urinary tract infections, intensive care unit infections, CAUTI, nurse leader rounds, hospital associated infections, indwelling urinary catheter.D.N.P., Nursing Practice -- Drexel University, 201
Neurochemical and electrophysiological characterization of target-specific neuronal populations in the dorsal raphe nucleus and their susceptibility to chronic corticosterone as a model of depression
No full textSerotonin (5-HT) neurons in the dorsal raphe (DR) nucleus project throughout the forebrain and are implicated in many homeostatic physiological processes and neuropsychiatric disorders. Heterogeneity among DR 5-HT neurons with respect to their anatomical relationships, neurochemical profiles, and electrophysiological properties is well-recognized, but only recently have studies begun aligning such phenotypic variations with specific brain functions. The goal of this work was to link DR neurons to the operation of cognitive and emotional circuitry or sensory processing networks by characterizing cells according to their neurotransmitter expression, electrophysiological profiles, and efferent connectivity; specifically, neurons projecting to the medial prefrontal cortex (mPFC, a region involved in cognition and mood regulation) or the lateral geniculate nucleus (LGN), a visual sensory relay. A further goal was to determine whether serotonergic regulation of cognitive/emotional function might be selectively impacted by a glucocorticoid-excess model of rodent depression; therefore, we examined the effect of chronic corticosterone (CORT) administration on the electrophysiology of these target-specific neuronal populations. Following retrograde tracer injection in mPFC or LGN (and once-daily subcutaneous injections of CORT at 40 mg/kg for 21 days in a subset of animals), rat brainstem sections containing the DR were immunohistochemically stained for 5-HT and co-transmitters or used for whole-cell patch clamp recordings. We found that neuronal nitric oxide synthase was expressed in a significantly greater proportion of neurons projecting to mPFC than to LGN (60% vs 22%)—a neurochemical bias consistent with the emerging role of nitric oxide in stress responses and depression. Additionally, only mPFC-projecting neurons displayed CORT-induced hypo-excitability, suggesting that protracted exposure to excess glucocorticoids may preferentially reduce 5-HT output in the mPFC. In summary, these data indicate that subsets of DR 5-HT neurons, defined by efferent connectivity and co-transmitter expression, respond selectively to elevated CORT levels and may account for functionally-specific differences in 5-HT transmission under normal conditions and in neuropsychiatric disease states. Based upon these initial findings we propose that the observed hypo-excitability in DR-mPFC projecting cells may underlie the cognitive deficits and emotional disturbances characteristic of depression and that functional enhancement of these cells may correlate with positive therapeutic responses to serotonergic antidepressants.Ph.D., Neuroscience -- Drexel University, 201
Calculus of Higher Order Noncommutative Functions
No full textThis thesis extends some standard results familiar from undergraduate calculus to the setting of higher order noncommutative functions. These extensions are accomplished using a difference-differential operator in a completely algebraic, topological free, manner. The results include a version of the mean value theorem, the Taylor formula and an antiderivative. The Taylor formula is applied to obtain results about power series on nilpotent matrices and higher order polynomials.Ph.D., Mathematics -- Drexel University, 201
A Qualitative Inquiry into the Experiences of Transgender Youth on High School Sports Teams
Get PDFIn the world of athletics, a hetero-masculine culture rules, and for many transgender athletes this can be a challenging environment. Transgender students face unique challenges in nearly every aspect of school life, and in many cases transgender students face opposition from ill-informed coaches and faculty members. This qualitative, phenomenological case study research explored the experiences of transgender athletes. The study is grounded in three theories: queer theory, social constructivism and critical theory. The purpose of this research is to examine lived experiences of recently graduated transgender students in order to promote understanding and facilitate the development of best practices for making high school campuses and athletic teams more welcoming for transgender students. The main research question is how do transgender, or gender variant recently graduated students reflect on their high school experiences as athletes competing on high school sports teams? This qualitative phenomenological study was conducted using open ended interview questions to collect qualitative data from transgender students who were asked to reflect on their experiences as a transgender high school athlete. The findings from the interviews include; misconceptions of the term transgender; lack of knowledge of transgender and gender variant individuals; teachers' and coaches' misperception of transgender; and a general lack of knowledge of biology and sex as it pertains to transgender. The participants' experiences are presented in two narrative forms composed across the participants' interviews but comprised entirely of their own words: (a) background profiles and (b) multiple, short narratives addressing various themes. This study is critical to help build understanding and empathy among all the students about transgender identity and issues; and to help transgender and gender non-conforming students feel more comfortable in school and develop positive self-esteem. Helping all students to be more knowledgeable, understanding, and empathic serves all constituencies in creating safe, welcoming, and more humane schools and communities.Ed.D., Educational Leadership and Management -- Drexel University, 201
Memory Accuracy and the Ability to Recall Psychological Distress and Behavior Over Time
No full textThe current study examined the accuracy/consistency of recollections of pre-therapy distress, problems, and episodic details, with an emphasis on understanding the degree to which memories of past emotions, distress, and behaviors are accurate/consistent, and the sources and direction of bias when they are inaccurate. Study participants (N = 20) recalled some types of psychological distress better than others and tended to overestimate their previous psychological distress. Increased current psychological distress was strongly correlated with decreased accuracy recalling interpersonal relationships. Regarding recall of previous problems, study participants endorsed a wide range of life problems and the number of problems endorsed was strongly correlated with the level of current psychological distress. Accuracy of recalling previous problems was strongly correlated with accuracy recalling pervious psychological distress. Memory accuracy for episodic details varied considerably and there was a strong relationship between increased time and reduced accuracy. Despite a small sample, the current study has potentially wide-reaching implications for medical and mental health professionals, as well as researchers who may all rely upon recall of symptom and behavioral information for diagnosis, clinical outcome evaluation, clinical research, and criminal responsibility evaluations. This study replicates previous findings related to recall of previous psychological distress, establishes future research priorities, and provides suggestions for future symptom recall research design.Ph.D., Psychology -- Drexel University, 201
Immersing Learners: The Influence of a Study Tour Course on Undergraduate Hospitality Students' Commitment to the Hospitality Industry
No full textThe hospitality industry constantly faces the challenge of identifying, recruiting, and retaining qualified and committed employees. The US government has recently proposed gainful employment legislation that would give the Department of Education (DOE) the authority to regulate for-profit colleges and certificate programs at not-for-profit institutions of higher learning, requiring them to meet minimum student debt ratios. These demands add to the pressure on hospitality college administrators to design courses and academic programming that not only prepare workers for their careers, but also reinforce student commitment towards working in a specific industry. This explanatory sequential research study was undertaken to investigate the influence a study tour course has on student commitment to the hospitality industry. Primary data collection methods included pre- and post-tour surveys of the 67 purposively selected study tour course participants and subsequent focus group interviews with participants recruited from that group. An analysis of the resultant data ensued to determine how completion of a study tour course influenced participants' levels of commitment to their chosen career path.Ed.D., Education -- Drexel University, 201
Investigating Quadruple Perovskites: Synthesis and Characterization of CaMn7O12 Films
No full textThe miniaturization trend in conventional electronics is approaching the limits beyond which the reduction of the electronic element is becoming more and more difficult. One way to continue the current trends in computer power and data storage increase without further size reduction is to use new functionalities such as charge-ordering or multiferroic behavior in devices. Complex oxide heterostructures are a materials platform that exhibit an unmatched array of collectively ordered states, including magnetism, ferroelectricity, and charge/orbital ordering, and are being researched for potential device applications. As a member of the quadruple perovskite family, CaMn7O12 exemplifies the rich physics that complex oxides can host. Previous work shows that this material in bulk form exhibits four distinct phase transitions: a charge-ordering transition at 430 K, an orbital ordering transition at 250 K, and two magnetic transitions at 90 K (TN1) and 45 K (TN2). Additionally, the magnetic ordering at TN1 induces ferroelectricity, which is the largest magnetically induced polarization yet reported. Despite the scientific interest and the technological potential for this material, there have been no reports of CaMn7O12 films prior to this thesis work. This dissertation is focused on establishing growth conditions for CaMn7O12 quadruple perovskite thin films using molecular beam epitaxy and pulsed laser deposition methods. By synthesizing thin films using both methods, I identify the key parameters in establishing the growth conditions for phase-pure CaMn7O12 films by evaluating cation stoichiometry and structural properties. To develop insight into the role of thin film structure-property relations, I explore how the electronic and magnetic structures of thin films compare to bulk. Then I develop insight into quadruple manganites by elucidating how the electronic and magnetic properties are tuned by chemical pressure effects through A-site substitution in Ca1-xSrxMn7O12 films. I identified the changes in charge-ordering, magnetic ordering, and helical spin structure through Sr-doping up to x ~ 0.6 by transport, magnetometry, and neutron diffraction measurements. These results provide fundamental insights into quadruple perovskite film synthesis and serve as a catalyst for future studies focused on AMn7O12 thin films. The material understanding of CaMn7O12 films obtained from this dissertation offers new avenues in the search and control of new functionalities in oxide heterostructures.Ph.D., Materials Science and Engineering -- Drexel University, 201
Exploring Aphasia Using Community Detection Analysis And Machine Learning
No full textAphasia, generally defined as an impairment in the production or comprehension of language, was first described in the late 19th century. Despite numerous critiques of the original model of aphasia proposed by Lichtheim in 1885 and advancements in neuroimaging, statistics and behavioral assessment techniques, the principles and sub-types Lichtheim proposed still play a large role in the sub-typing framework used in clinical aphasiology today. Therefore the current project sought to explore aphasia diagnoses using a data driven approach and modern statistical tools by examining the behavioral deficit profiles and their lesion correlates in a large cohort of patients. The project consisted of three studies. Study 1 sought to address concerns of poorly defined aphasia sub-types, by using community detection analysis (CDA) to cluster patients with aphasia based on their behavioral profiles and to then compare these clusters to the traditional sub-types to see how well they align. Building from Study 1, in the second study voxel-based lesion symptom mapping was used to identify neural regions specific to the clusters identified in Study 1. Finally, in Study 3 classifiers were built in attempts to try and predict a patients cluster based solely on their lesion profiles. Overall the results of the CDA and VLSM analyses did not align with the traditional model of aphasia and suggest that the primary distinction in aphasia after severity should be between phonological and semantic processing rather than production and comprehension as traditional models suggest. Further the classifier was successful in categorizing patients and/or predicting a patients deficit showing potential for tools such as these to be used clinics. In all the results of this study suggest that the field needs to start moving in a new direction in regards to the study and classification of aphasia types.Ph.D., Psychology -- Drexel University, 201
Extracting Meaningful Features from Noisy Microbiome Data
No full textThe increasing availability of microbiome survey data has led to the use of complex machine learning and statistical approaches to measure taxonomic diversity and extract relationships between taxa and their host or environment. Accurately representing microbiome community structure has notable implications in medicine because recent work has demonstrated bidirectional interplay between microbiota and various organ systems. However, many approaches inadequately account for difficulties inherent to microbiome data, such as (1) insufficient sequencing depth resulting in sparse count data, (2) a large feature space relative to sample space, resulting in data prone to overfitting, and (3) library size imbalance, requiring normalization strategies that lead to compositional artifacts. Still, there exist approaches from other domains (e.g., natural language processing) that may be well-equipped at fitting microbiome data and may provide meaningful features that capture relevant aspects of the data. Two methods in particular are topic models and word embeddings, which characterize word co-occurrence as topics and capture semantic and lexical information of each word based on the word's neighbors, respectively. In this work, we show that a topic model can represent microbiome abundance data as topics, capturing ``subcommunity'' structure from co-occurrence patterns among taxa, whereas word embeddings can represent a nucleotide subsequence as a dense, numeric vector that encapsulates the nucleotide neighborhood in which the subsequence exists. Specifically, we present two approaches, both of which are applied to 16S rRNA amplicon surveys. First, we utilize a topic model approach. We show that library-size normalization is unnecessary and, by exploiting topic-to-topic correlations, the topic model can successfully capture complex signals such as dynamic time-series behavior of taxonomic subcommunities. In addition, we present themetagenomics to demonstrate that topic features are flexible for downstream analysis. We link taxonomic co-occurrence to their predicted functional content by leveraging gene function prediction algorithms and a fully Bayesian multilevel regression model. Second, we use Skip-Gram word2vec and a recent sentence embedding approach to embed nucleotide sequences. Our results show that embedding sequences results in meaningful representations that can be used for exploratory analyses or for downstream machine learning applications that require numeric data. The sequence embeddings can preserve relevant information about the sequencing data such as k-mer context, sequence taxonomy, and sample class. The insights we provide are applicable to various types of count data that extend beyond the microbiome sequencing domain. These include ecological presence/absence surveys, RNAseq gene expression studies, metagenomic or whole genome sequencing studies, proteomic or metabolic research, text-based studies, and econometrics. In addition, our approaches for exploring the sequence embedding space are applicable to any type of text-base research, including genetics and natural language processing, as well applications utilizing deep learning, where embedding layers are used to encode text for deeper layers of the network. Lastly, our simulation approaches and evaluation of normalization techniques are generalizable, such that aspects of these strategies could be applied to microbiome studies and work consisting of compositional data other than 16S rRNA amplicon surveys.Ph.D., Electrical Engineering -- Drexel University, 201