Revisiting Capital Accumulation: Implications for Business Cycles and Productivity Growth

This thesis consists of three chapters that look at the business cycle and productivity implications of relaxing certain assumptions regarding capital accumulation. In the first chapter, I introduce capital search frictions into an otherwise standard Real Business Cycle model. New and used capital markets are separate and used capital reallocation is subject to search frictions. The model produces the desired property of procyclical reallocation of used capital in equilibrium in line with business cycle data facts. The second chapter relaxes the assumption that capital depreciation is exogenous, to study the implications of such an assumption on productivity growth. In a Dynamic Stochastic General Equilibrium model where capital depreciation varies with the rate of technological innovation, the model finds that failure to account for depreciation's endogenous response to technological changes, only biases productivity measures when the economy is switching regimes. Along the Balanced Growth Path, when the rate of technological innovation is fixed, the econometrician who computes Total Factor Productivity from standard growth accounting, using capital stock with constant depreciation, will exactly pin down true productivity. The model is then used to study two main episodes of productivity slowdown in the US, the slowdown of the early 1970s and that of the mid 2000s. As the economy switches from a higher to a lower growth rate of technology in the early 1970s, failure to account for endogenous capital depreciation overestimates the slowdown by approximately 15%, while the opposite is true in the mid 2000s. As the economy switches from a higher to a lower growth rate of technology, the true slowdown is underestimated by approximately 5% when capital depreciation is kept constant. The third chapter proposes two approximations of the non-recursive, infinite horizon model of endogenous depreciation used in the second chapter, otherwise known as the Putty-Clay model, in order to implement and solve the model in Dynare. The first approximation is based on the assumption that it takes a capital vintage a certain number of periods to fully depreciate. This assumption takes care of the infinite horizon problem and the contribution of the paper is to show how to automatize and solve this non-recursive model in Dynare using its first-order perturbation methods. The second method proposes approximating the non-recursive equilibrium equations through a time-series process of lag one that preserves the dynamics of the putty-clay model. While the first method automatizes the non-recursive model in Dynare for any general number of periods, it is computationally expensive, which matters for estimation. The recursive approximation method can resolve this issue by reducing the state-space of the model.Ph.D., Economics -- Drexel University, 201

"In My Neighborhood, But Not For Me": Long-Standing African American Residents' Perceptions of Gentrification, Anchor Institution Expansion and the Paradox of Civic Engagement

This dissertation explores perceptions and sentiments held about the presence and increased expansion of a private, urban university by the residents whose neighborhood shares its border. The historical and current engagement of a predominantly White institution, Fourdlet University, with the low-income, predominately African American Greatland community was elucidated through the voices of 10 long-standing residents. Long-standing residents were defined in this study as those members who have resided for a minimum of 20 years in Greatland. Recent expansion of the university into the residential neighborhood has resulted in the gentrifying of a community that once represented multiple generations of predominantly African American families. While the neighborhood population is increasingly younger and whiter, the African American population has been reduced to a small number of primarily older residents who have been able to maintain ownership of their homes. This was a narrative ethnographic study conducted over a five-month period wherein critical race theory (CRT) served as its foundation due to the historical racial tensions between the university and the neighborhood. With its emphasis on voice, counternarratives, and challenges to systemic societal racism, CRT illuminated the visceral understandings possessed by neighborhood residents about the expansion and changes in racial composition in their community. This research contextualized whiteness as property considering the significance of property ownership and the deliberate process of gentrification currently experienced in the lives of Greatland residents. Additionally, this study viewed its subject through the lenses of mere exposure theory and the ecological theory of social perception. These theories served to explore impression formation and how judgements made about the roles and responsibilities of the university and the civic mission of higher education translate into the sentiments and perceptions that residents hold regarding the expansion of the university. Scholarship detailing both how residents in gentrifying communities experience civic engagement efforts and the necessity of translating such efforts into the expressed civic mission of an anchor institution is at best difficult to locate in an explicit format; at worst, it is nonexistent. Frequently found is the problematic tendency to conflate the descriptions of the two, and was revealed as a challenge for Greatland residents who seek to understand the intention of Fourdlet University's progression into the neighborhood. From this challenge emerged the themes of this study: Underwhelmed by the Performance, Disrespecting the Community, and Invest in the Children of the community. The impression that the university has made within the context of engaging the community as its partner, has not engendered strong positive sentiments. Residents have expressed deep concern with the displacing effect of the increased expansion of the university through actions and attitudes that they view as disrespectful, particularly when the actions instigated by the university do little to strengthen the stability of the community. Finally, among the participants there was consensus that the university should more aggressively cultivate relationships with the young people of Greatland with the specific intent to admit and graduate them from the institution. Implications of these findings suggest an emerging understanding of the need for anchor institutions to become more instrumental in policy reform and to deliberately and strategically use their economic power to address educational, income, and wealth inequality based upon the shift in dialogue toward devising anchor missions and more clearly articulated civic missions. Historical precedence exists of residents achieving success in creating and maintaining wealth within the community, thus the enactment of initiatives such as Community Benefits Agreements, wherein the community voice would be more prominent in neighborhood planning efforts, would be well suited to assist the community in re-establishing self-sufficiency. Implications are that residents will continue to assume agency by relying upon their collective knowledge to push back against development that progresses as a result of university expansion, however, the findings of this study reveal that the implications of race and racism on the issue of institutional expansion is a foundational issue that must be addressed. A symbiotic relationship is a defining feature of an anchor institution and its surrounding community. However, the persistent racism that participants articulated experiencing as a result of university expansion would potentially render such a relationship difficult to achieve in the absence of concerted efforts to elucidate for the community how it will benefit from the university's presence.Ed.D., Educational Leadership and Management -- Drexel University, 201

Sex Differences in the Endocannabinoid System: Implications for Stress-Related Psychiatric Disorders

Stress-related psychiatric disorders including post-traumatic stress disorder (PTSD), depression, and anxiety are among the most prevalent conditions in the world, and their incidence continues to rise each year. These patient populations are comprised of more women than men and are difficult to treat as the underlying neurobiology is complex, and a diverse array of symptoms present clinically, often in a sex-dependent manner. The dysregulation of the stress-responsive locus coeruleus–norepinephrine (LC-NE) system has been implicated in the onset and progression of many psychiatric diseases, and restoration of LC-NE function is associated with resolved symptoms in cases of successful treatment. Brain endocannabinoids (eCBs) are ubiquitously expressed neurotransmitters involved in the regulation of many physiological processes, including modulating behavioral responses to stress. The LC is a target of eCB action and exerts its influence via the cannabinoid type 1 receptor (CB1r). The eCB system is capable of enhancing or reducing LC responsivity to various physiological and environmental stimuli. Thus, targeting the eCB system may have therapeutic potential in treating stress-related psychiatric disorders, in part, by modulating the LC-NE system. Conventional pharmacological approaches are often only successful in a subpopulation of afflicted individuals. Therefore, the purpose of the present study is to characterize compensatory mechanisms in the eCB system under conditions of NE depletion, a model of symptoms that arise in patient subpopulations that are difficult to treat such as atypical depression. Protein expression levels of a key enzyme in the biosynthesis of the eCB 2-arachidonoylglycerol (2-AG), diacylglycerol lipase-[alpha] (DGL-[alpha]), as well as two eCB degrading enzymes monoacylglycerol lipase (MGL) and fatty acid amide hydrolase (FAAH) were examined in the LC of mice that lack the NE-synthesizing enzyme, dopamine [beta]-hydroxylase (D[beta]H-knockout, KO) and in rats treated with N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine hydrochloride (DSP-4), an LC-specific neurotoxin. In D[beta]H-KO mice, DGL-[alpha] expression was significantly increased in both sexes when compared to wildtype (WT). While MGL expression was not altered in either D[beta]H-KO, FAAH expression was significantly reduced in female D[beta]H-KO groups compared to WT. In DSP-4 male rats, DGL-[alpha] expression was significantly increased compared to saline-treated controls, and a similar trend was observed in DSP-4 treated female rats. There were no observed differences in either groups for MGL expression. Meanwhile, FAAH was found to be significantly decreased in DSP-4 treated males and significantly increased in DSP-4 treated females. Thus, the results of these findings suggest increased eCB tone in DSP-4 treated male rats and overall increased turnover in female DSP-4 treated rats. The results indicate that sex-specific strategies may be advantageous for stress-related therapeutics which are aimed at modifying the LC-NE system via the eCB system.M.S., Drug Discovery and Development -- Drexel University, 201

Hedonic Hunger, Disinhibited Eating, and the Physiological Impact of Palatable Food: A Study of Heart Rate Variability

Hedonic hunger and disinhibited eating behaviors, such as loss of control eating and eating in the absence of hunger, represent increased motivation for food and susceptibility towards overeating and are associated with a range of adverse physical and psychological outcomes. The persisting prevalence of these symptoms suggests limited efficacy of current prevention efforts and establishes the need for the identification of additional risk and maintenance factors. Heart rate variability (HRV) has been established as a measure of biological responsiveness and psychological well-being and may function as a physiological marker of food responsivity. Preliminary evidence has identified associations between reduced HRV and eating disorder symptoms, suggesting that eating pathology may be associated with different physiological responses to food. The current study sought to replicate and extend previous findings by employing HRV as a measure of arousal in response to food presentation across different hunger conditions in healthy adults. We examined relationships between multiple indices of HRV (HF, LF, LF/HF) and measures of hedonic hunger, loss of control eating, and eating in the absence of hunger. Results found similar patterns of HRV in response to food exposure and intake as previous research in nonclinical samples, with reduced HF HRV during food exposure and food intake and increased HF HRV following food intake. Although there was a marginally significant interaction between hedonic hunger and PFS, subsequent analyses found no relationship between HRV and PFS, LOC or EAH. Limitations and implications of the study are discussed.Ph.D., Psychology -- Drexel University, 201

The Complete Interactome with 5-D GPU Accelerated Analysis, Visualization, and UI for Biological Microscopy Applications

Microscopes now have the ability to collect highly complex data. This thesis presents new algorithms and software packages for analyzing, visualizing, and interacting with biological microscopy image datasets. These new software packages provide functionality not available with existing methods. Along with new functionality, the methods described here are of higher accuracy compared to existing methods. These new software packages provide significant improvements in computational efficiency and usability. Contributions described within this thesis are biologically motivated with examples given throughout. The analysis presented has enabled new biological discoveries along with new mathematical analytic techniques. This thesis is broken into three distinct areas: analysis of interactions between organelles describing the complete interactome, a hardware accelerated image processing library, and software packages providing visualization, validation and analysis. First the complete interactome describes a new method of quantifying the interactions of all of the organelles within a single cell. Where prior methods focus on pairwise interactions, methods described here include a robust quantification method for these high order interactions. Secondly, a hardware accelerated image processing library and framework called Hydra Image Processor (HIP). HIP is capable of swiftly processing arbitrarily large datasets. The HIP framework automatically (without user intervention) distributes data and schedules processing across all available graphic processing units. In addition, HIP processes the edges of images with higher precision than currently available methods. Lastly, visualization, validation, and analysis tools are presented. Visualization of high dimensional datasets captured by modern microscopes is non-trivial. Integrating processing, segmentation, and tracking results embedded is also a challenge. Software packages presented here perform all three of these task within the scripting environment of MATLAB for fast prototyping and swift user interface generation. Validation tools are also described that incorporate user input to inform unsupervised algorithms and reduce underlying segmentation and tracking results significantly. All methods and contributions of this thesis are biologically motivated. Within the three areas described above are biological examples where these methods contributed significantly. They range from describing the high-order interactions within a single cell, to lineaging stem cells in 5D, to the reconstruction of large montage images of the Subventricular Zone. The adoption of these methods will enable future biological findings within highly complex datasets captured by modern and future microscopes.Ph.D., Computer Engineering -- Drexel University, 201

Metadata for the International Health Workforce: Professional Regulation, Credentialing, and Health Policy Planning

Purpose: National health regulatory authorities ensure access to adequate health care by verifying the credentials of health professionals and monitoring of the volume and distribution of the health workforce. This work is made more complex by the growing international mobility of health professionals and is dependent upon timely and accurate data describing professionals in detail; however, there is no accepted standard for exchanging these data. This dissertation takes steps to address this need by identifying the specific data needs of the medical regulatory community and assessing the degree to which existing standards meet the community’s information needs. The overall goal is to identify the unique data needs of regulators while encouraging future interoperability of data describing health professionals. Design and Methods: This study employs a mixed-methods approach combining a document analysis of application forms from 20 international regulatory agencies, a survey of medical regulators, and crosswalk matrices mapping agencies’ required information items together and comparing those items to existing schemas. Multiple methods of data collection from international sources provide a more complete picture of the information needs of the medical regulatory community. The final crosswalk mapping of required elements to three existing metadata schemas was used to assess whether certain topic areas or specific metadata elements are adequately addressed by current standards. Findings: An analysis of 20 international agencies’ documents yielded 1498 application items that could be mapped to 204 distinct metadata elements required by regulators to describe health professionals in support of licensure decisions. An examination of three existing schemas representing agents and their qualifications – the Europass schema, the HR Open Standard, and the MedBiquitous Professional Profile Standard – and creation of a crosswalk matrix mapping their elements to those required by regulatory agencies showed none contained more than half of the metadata elements required. Excluding elements imprecisely matched, the most comprehensive schema addressed only 30.9% of the elements required. Practical Implications: There are many required elements that cannot be represented in existing schemas. In particular, crucial data describing any potentially negative aspects of an individual’s profile, such as disciplinary actions taken against the professional or malpractice payments they have made, are partially or wholly unsupported by any of the schemas examined. Full support of the regulatory community’s information needs would require the addition of certain elements or element sets to existing schemas. Value: This study provides valuable guidance to regulatory agencies in furtherance of an international data standard for their community. Additionally, this work establishes a practical methodology for contextual data standards evaluation based on document analysis.Ph.D., Information Studies -- Drexel University, 201

Processing - Structure - Performance Relationships: A Rheological Perspective

Optimal performance of commercial battery electrodes is dependent on a homogeneous distribution of three components: 1) active material 2) conductive additive 3) polymer binder. In commercial batteries, the conductive additive and polymer binder are less than 10\% of the entire electrode, but homogeneous distributions of these components is non-trivial and greatly impacts electrode performance. Processing of battery electrodes is a multi-step process with a multitude of variables that could possibly impact homogeneity. Typically the study of processing parameters is associated with manufacturers. However, processing parameters are not universal or well transplanted from system to system and as a result academia has begun to investigate processing from a fundamental standpoint. Literature has demonstrated the complex relationship between processing and performance and how correlations can become convoluted if careful experimentation is not performed. During the first unit operation, an active material, conductive additive and polymer binder are dispersed in solvent creating a slurry. Battery slurries can create a wide variety of microstructures depending on the specific components, concentration, and component interactions. Rheological measurements have risen in prominence as tools to better understand the battery slurry's microstructure. The work presented here investigates the fundamentals of the mixing unit operation and its impact on the slurry microstructure and electrode performance. The first part of the work presented here investigates the particle-polymer interactions that develop in Lithium Nickel Manganese Cobalt Oxide (NMC), carbon black (CB) and polyvinyldiene diflouride (PVDF) cathode slurries and how they are impacted by component parameters and shear during mixing. The investigation determined that depletion interactions develop between the CB particles and PVDF, the sign of which determined whether CBs attraction to itself is increased or decreased. In the case of low molecular weight PVDF, the attraction between the CB particles increases due to the presence of PVDF. The increased attraction causing flocculation of the particles and at a critical volume fraction of particles a gravity withstanding network formed. Interestingly, the presence of NMC particles does not impact the gelation transition. Since the NMC particles do not participate in gelation the microstructure is directly related to the concentration of CB in the slurry. On the other hand, when high molecular weight PVDF is used gelation of CB is prevented by changing the sign of the interaction potential. Shear during mixing was shown to be sufficient enough to cause polymer scission of the PVDF chains decreasing molecular weight and causing gelation when high molecular weight PVDF was started with. Uncontrolled polymer scission was also shown as a potential reason for reproducibility issues during processing. Overall the first two chapters demonstrate how different slurry microstructures develop and its dependence on component size and mixing parameters. Once the basics of creating the initial slurry microstructure was determined, the role of other processing steps could be considered. The second half of the work presented here investigates how a processing step called "dry-mixing" impacts the electrode performance and techniques for investigating electrodes. Dry-mixing coats the conductive additive onto the surface of the active material prior to wet mixing with the polymer binder and solvent. By investigating dry-mixing at commercially relevant concentrations of CB, it was determined that dry-mixing improves performance by decreasing the resistance between active material particles. It is difficult to measure particle-particle resistances directly. Particle-particle resistances are incorporated into the Dualfoil(c) model for Li-ion batteries. Preliminary investigations into the use of this model are documented. Additionally this work discusses combining energy dispersive x-ray spectroscopy (SEM/EDS) and x-ray computational tomography (XCT) for mapping of the conductive additive and polymer binder in electrodes. Due to the elemental and density similarities of the conductive additive and polymer binder they are difficult to distinguish in both techniques. The use of a contrast agent was shown to improve both SEM/EDS and XCT results and allow for material specific connectivity to be calculated in XCT. The work presented here sets the frame work for fundamental investigations into the impact of processing on electrode performance. By using a consistent high performance electrode system conclusions about performance can be made in the absence of electrochemical limitations. The findings presented here demonstrate that complex interactions occur during mixing and that a variety of fluid phase microstructures can develop. In addition, the work presented here addresses the issue of reproducibility and demonstrates that short-range particle-particle resistances are the main limiting property in commercial battery electrodes. This work hopes to create a basis on which further understanding of the importance of processing can be based.Ph.D., Chemical Engineering -- Drexel University, 201

Child Care Center Directors' Perceptions of their Efforts to Create Inclusive Environments in a Quality Rating and Improvement System (QRIS)

Under the Individuals with Disabilities Education Act of 2004 (IDEA, 2004a) and the Americans with Disabilities Act (1973), children with delays and disabilities have the right to access similar settings as their typically developing peers to receive care and education, which includes participating in community-based child care centers. A significant financial investment was made by the federal government through the Child Care and Development Block Grant Act of 2014 (CCDBG) to ensure that child care settings provide quality care, which triggered the implementation of quality rating and improvement systems in the majority of states (Quality Compendium, 2016). However, a setting deemed as high quality is not enough to ensure that effective instruction is provided adequately to meet the individual needs of children with disabilities in early childhood settings (Soukakou, Winton, West, Siders, & Rucker, 2014; Wolery, Pauca, Brashers, & Grant, 2000). This hermeneutic phenomenological study described the lived experiences of child care center directors as they engaged in providing quality care for children with disabilities in their settings by exploring (a) trends in quality improvement initiatives in early childhood education, (b) quality rating and improvement systems (QRIS) as an essential framework for quality improvement, and (c) inclusive practices in light of the implementation of these systems. Experiences of child care leaders as they engaged in providing care for children with delays and disabilities in an urban setting were explored with a focus on the following central question: How do child care center directors, participating in the quality rating and improvement system (QRIS), perceive inclusion? Participants were purposefully selected based on their responses to the continuous quality improvement plan (CQIP) and placed into two categories (a) responders to the inclusion indicator of the state's CQIP and (b) those who did not respond to the inclusion indicator of the CQIP. Data were collected through analysis of semi-structured interviews and coded in effort to find common themes in the experiences of the participants. The themes that emerged were: similarities related to perceptions of inclusive practices, differences related to perceptions of inclusive practices, perceptions of how QRIS supports inclusive practices, and recommended enhancements to QRIS that support inclusive practices. Recommendations were made for increasing inclusive practices by means of local and national QRIS implementation through the experiences of child care center directors who participated in this study.Ed.D., Educational Leadership and Management -- Drexel University, 201

The Potential Impact of Raw Milk on the Small Intestine Microbiome: An in vitro project

Homogenization and pasteurization are common processing techniques used in the dairy industry on bovine milk to produce a uniform fluid that does not separate while stored and is virtually free from harmful bacteria. Many raw milk proponents however argue that these processes damage the nutritional value and in turn could be harmful to the gut microbiota. Many articles have been published, studying the relationship of milk processing and its subjection to in vitro digestion, however little information is available about the effects of milk on the small intestine microbiome. This project aims to compare and add to the current work on milk and the microbiome with the use of bioreactors, and to provide future experimentation procedures and suggestions for use of the data.M.S., Food Science -- Drexel University, 201

Game Shows and Late-Night Talk Shows: Keeping Audiences Engaged in a World of Ever-changing Technology

The purpose of this study is to show how game shows and late-night talk shows have evolved with advancing and changing technology. Both game shows and talk shows had to incorporate new technology into their development in order to stay relevant and successful. Most shows are now using social media heavily to further engage their viewers. Some also are taking advantage of live streaming, blogging and podcasting. The study presents an analysis that may be useful in guiding television industry leaders to a strategy that maximizes the yield from resources they will invest to reach the most desirable target demographics.M.S., Television Management -- Drexel University, 201