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Title: DEVELOPMENT OF A NEWS SUBSCRIPTION MOTIVATION SCALE
Creator: Chen, Weiyue
Date: 2022
Collection: Electronic Theses & Dissertations
Description: As news organizations face accelerated loss in advertising revenue, increasing importance is placed on strategies to increase subscription sales. Although previous studies have found several predictors of paywall, willingness to pay, and paying for news research, these factors did not fit into one clear conceptual framework that links them together. In this dissertation, I aim to introduce a new construct, News Subscription Motivation, that provides theoretical linkages between different...
Show moreAs news organizations face accelerated loss in advertising revenue, increasing importance is placed on strategies to increase subscription sales. Although previous studies have found several predictors of paywall, willingness to pay, and paying for news research, these factors did not fit into one clear conceptual framework that links them together. In this dissertation, I aim to introduce a new construct, News Subscription Motivation, that provides theoretical linkages between different predictors of paying for news. Mixed method research was employed to conceptualize and operationalize this new construct. In Chapter 1, I discuss my thought process developing this study, the purpose of the study, and why this topic matters in the context of digital economy. Chapter 2 includes a review of previous research on what drives people to pay for news, and the literature on consumer decision-making processes, consumer decision-making styles, and consumer motivation in general. The need to develop a new construct and measurement tools that are specially designed for news consumption was also addressed. In Chapter 3, I conducted 22 in-depth interviews to generate possible dimensions of the construct, analyzed the qualitative data to propose a conceptual framework and definition. Study 1 results suggested nine possible dimensions: content utility, journalism quality, price, convenience, hitting the paywall, surveillance, being a good citizen, brand reputation, and journalism. Conceptual definitions of each dimension were also elaborated. Chapter 4 focuses on the operationalization of News Subscription Motivation. An initial items pool was generated based on Study 1. After the pilot test, I recruited two independent samples, and they were respectively subjected to Exploratory Factor Analysis and Confirmatory Factor Analysis. The final scale included six dimensions with 19 items, and this scale demonstrated robust model fit and adequate convergent and discriminant validity. Six dimensions of News Subscription Motivation were identified: supporting journalism, journalism quality, triggered by the paywall, community attachment, price, and content utility. In Chapter 5, I aim to establish the nomological validity of News Subscription Motivation. Factors extracted from Chapter 4 demonstrated statistically significant relationships with numbers of news subscription people report paying for, types of subscriptions people get, and individuals’ intention to maintain their primary subscriptions in the next 3 months, 6 months, and 12 months. Finally, I discuss the theoretical and practical implications of the scale of News Subscription Motivation in Chapter 6.
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Title: The efficacy of implementing a technology-mediated dialogic pedagogy to support reading comprehension in virtual and co-located settings
Creator: Working, Christopher Scott
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Text-based discussion within a technology-mediated dialogic discussion (T+DLD) has the potential to engage students in higher-level reading comprehension with upper elementary students. While supported empirically, this approach is still not commonplace, and little is known about its efficacy within a remote setting. The primary aim of this project was to synthesize what is currently known about T+DLD and to explore changes in discussion within a remote setting to support practitioners...
Show moreText-based discussion within a technology-mediated dialogic discussion (T+DLD) has the potential to engage students in higher-level reading comprehension with upper elementary students. While supported empirically, this approach is still not commonplace, and little is known about its efficacy within a remote setting. The primary aim of this project was to synthesize what is currently known about T+DLD and to explore changes in discussion within a remote setting to support practitioners enacting the approach. This was achieved through a systematic review of the literature on T+DP that analyzed 18 included studies for study quality as well as patterns around study features (i.e., instructional design, environmental factors, task, methodology). Text-based discussion via web-based teleconferencing was studied using a comparative case study using sociocultural discourse analysis to study student discussion in three different training conditions: dialogic only, technology only, and a T+DLD training. A pathway of implementation was then developed to translate research into practice to support teachers in adopting T+DLD. A key finding within this project was that T+DLD builds on the key elements of ground rules for talk, an open task, and student reflection for talk. Additionally, the pedagogical approach of the teacher influences the way technology is used by students. Finally, technology can successfully support T+DLD in both co-located and remote settings. This dissertation provides recommendations for future research that compares methods of implementation and evaluates the direct impact on reading comprehension.
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Title: THREE ESSAYS ON THE CHOICE OF COLLEGE MAJOR AND TRADE EXPOSURE
Creator: Wu, Yu-Siang
Date: 2022
Collection: Electronic Theses & Dissertations
Description: This dissertation is composed of three chapters on the effects of import exposure. For my dissertation I mainly use the variation of import competition across local labor markets to explore its impact on labor market outcomes (e.g., wages and employment status), human capital investment decisions (choice of college major), and education-job mismatch.Chapter one explores the relationship between increasingly intense Chinese import competition and American college students’ choice of major in...
Show moreThis dissertation is composed of three chapters on the effects of import exposure. For my dissertation I mainly use the variation of import competition across local labor markets to explore its impact on labor market outcomes (e.g., wages and employment status), human capital investment decisions (choice of college major), and education-job mismatch.Chapter one explores the relationship between increasingly intense Chinese import competition and American college students’ choice of major in the 2000s. By employing a modified version of the measure for Chinese import competition from Autor, Dorn, and G. Hanson (2013) and analyzing the relationship between industries and college majors, I find that rising Chinese trade exposure of nineteen industries in the 2000s has a negative effect on American students’ choice ofsix engineering majors. The magnitudes of the effects range from 0.62 to 0.69 percentage point decreases in the probability of choosing those six engineering majors. I also find that males are more negatively affected by Chinese import competition in terms of the choice of the six engineering majors, whereas no significant results exist if I restrict my sample to females.Chapter two analyzes how increased trade exposure affects students’ choice of STEM major. I first present a simple model to illustrate how trade exposure impacts students’ utility functions through their self-beliefs about labor market outcomes and then use assorted data to show that import competition positively affects the choice of STEM major. I find that increased import exposure in the 2000s leads to 1.05 and 0.72 percentage point increases in the probability of choosing STEM majors for college underclassmen and upperclassmen, respectively. As for labor market outcomes, my results suggest that a rise in import competition leads to a pronounced negative effect on weekly wages, employment status, and full-time employment across STEM and non-STEM occupations from the late 1990s through the 2000s. STEM occupations, however, are less negatively impacted by import competition, which helps explain why a rise in import exposure increases the probability of students choosing STEM majors.Chapter three investigates the impact of import exposure on education-occupation mismatch. I first use the concept of a matching function to explain the connection between mismatch and the supply of and demand for college graduates. Next, I use an input-output table to construct a measure of import exposure that accounts for both direct and indirect trade shocks. Findings show that increased import exposure leads to a rise in education-occupation mismatch from 2011 through 2019. Moreover, for the supply side I present that a rise in import exposure significantly increases the number of bachelor’s degrees awarded in 4-year colleges and in most degree fields. However, for the demand side, I do not observe corresponding increases in occupational employment for most fields of education. The unbalanced demand for and supply of college graduates might potentially explain the rise in education-occupation mismatch.
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Title: Differential Effects in Exposure to ACEs and Problematic Drinking : An Examination of Protective Factors
Creator: Welch, Timothy Sean
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Exposure to Adverse Childhood Experiences (ACEs) has been associated with numerous negative developmental outcomes across the lifespan, including problematic drinking. However, not all individuals exposed to ACEs go on to drink problematically. This difference in the effect of exposure to ACEs on drinking use is an example of heterogeneity and is called a differential effect. Relatively little research has examined what factors predict resilience to the harmful effects of ACEs. Most existing...
Show moreExposure to Adverse Childhood Experiences (ACEs) has been associated with numerous negative developmental outcomes across the lifespan, including problematic drinking. However, not all individuals exposed to ACEs go on to drink problematically. This difference in the effect of exposure to ACEs on drinking use is an example of heterogeneity and is called a differential effect. Relatively little research has examined what factors predict resilience to the harmful effects of ACEs. Most existing research has examined either a single protective factor or examined the total number of protective factors in a cumulative scale. No study has yet to specifically examine differential effects in the context of ACEs and alcohol use. The aim of this study was to examine differential effects in exposure to ACEs and alcohol use to empirically identify a resilient group of individuals. Two research questions drove this study 1) How can heterogeneity in the association between ACEs and alcohol use be characterized? and 2) What factors predict group membership? Using data from the National Longitudinal Study of Adolescent to Adult Health (Add health), two complimentary analytic tools were used to achieve these aims: Regression Mixture Modeling (RMM) and Structural Equation Model Trees (SEM trees). Results from the RMM found evidence of two groups: a resilient group consisting of 72.6% percent of the sample and a harmful effects group consisting of 27.4% percent of the sample. Two factors were positively associated with belonging to the resilient group, school bonding and self-control. One factor, having a mentor, was associated with a lower likelihood of being in the resilient group. Results from the SEM-tree divided the data into three groups based on two variables: self-esteem and having a mentor. In this analysis, higher self-esteem and having a mentor during adolescence were both associated with problematic drinking. Findings from this study provide empirical evidence of a resilient group of individuals for whom there is not an association between exposure to ACEs and alcohol use. Despite testing multiple theoretically based protective factors, only school bonding and problem solving were associated with resilience. This suggests future research should consider additional alternative protective factors. The results suggest therapists and clinicians working with youths exposed to ACEs should work to foster increased levels of school bonding during adolescence and should assess levels of self-control and focus on helping youths develop greater self-control.
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Title: SLEEP MANAGEMENT AS A COLLABORATIVE WORK FOR THE FAMILY : DESIGNING SLEEP MANAGEMENT SYSTEMS TO IMPROVE BEDTIME ROUTINE
Creator: Shin, Ji Youn
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Sleep is a vital health issue. In families with young children, sleep problems can influence the physical, emotional, and behavioral health of all family members. Previous studies have investigated sleep as an individual activity, rarely considering the interconnected aspects of sleep among family members. To understand the social aspects of family sleep, this dissertation consists of two studies which can help researchers and designers understand the core issues of family sleep and address...
Show moreSleep is a vital health issue. In families with young children, sleep problems can influence the physical, emotional, and behavioral health of all family members. Previous studies have investigated sleep as an individual activity, rarely considering the interconnected aspects of sleep among family members. To understand the social aspects of family sleep, this dissertation consists of two studies which can help researchers and designers understand the core issues of family sleep and address them through the design of sleep-support technology. In the first study, I identified sleep as a complex experience entangled with the social dynamics between family members. For example, children's sleep means time not just for children to rest, but for a parent to have self-care. The results suggested how the boundaries that define sleep in terms of time (at night), space (in bedrooms), and unit of analysis (individual-focused) limit designers' opportunities to tackle the deeper sleep issues of families. I also suggest "division of labor" as an important but rarely discussed design concept to enhance family sleep, and as a promising design theme for home technologies that address issues emerging from social dynamics between household members. In the second study, by incorporating the identified themes from the first stage, I designed and tested two types of family-based sleep management prototypes. These prototypes redistributed the sleep-relevant tasks among family members and provided them with chances to reflect on the difficulties and values involved in the tasks. Through the in-the-wild study deploying two design prototypes in home settings, this study empirically revealed the importance of considering social dynamics as a design factor for family sleep management technologies. Implications of future design are discussed.
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Title: Assessing Theoretical Mediators of Campaign-Induced Communication in the Context of Social Norms Campaigns
Creator: Park, Sunyoung
Date: 2022
Collection: Electronic Theses & Dissertations
Description: The present paper examines the role of campaign-induced communication on the effects of a social norms campaign by focusing on cognitive elaboration, perceived injunctive norms, and message recall as mediating variables. Participants (n = 252) read an injunctive norms campaign message about choosing not to drink at parties or when socializing and were randomly assigned to one of three conditions (control: received no prompts, prompt only; received prompts to engage in interpersonal...
Show moreThe present paper examines the role of campaign-induced communication on the effects of a social norms campaign by focusing on cognitive elaboration, perceived injunctive norms, and message recall as mediating variables. Participants (n = 252) read an injunctive norms campaign message about choosing not to drink at parties or when socializing and were randomly assigned to one of three conditions (control: received no prompts, prompt only; received prompts to engage in interpersonal communication about the campaign message with close others during the following week; prompt & plan: received prompts to engage in interpersonal communication with close others during the following week and to write a plan for the communication). The results revealed that the prompt (either alone or with the plan) significantly motivated participants to engage in positive conversations about the campaign message during the next week. Similar to past findings (Morgan et al., 2018), a higher frequency of positive conversations about the campaign message indirectly predicted better behavioral outcomes via higher cognitive elaboration. The findings suggest that social norms campaign developers should be encouraged to design social norms messages with a brief prompt to motivate the target audience to engage in interpersonal communication and need to account for such interpersonal communication and its indirect effects in evaluating campaign messages.
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Title: THROUGH THE MAGMA MUSH : TRACING MAGMA EVOLUTION FROM THE MANTLE, THROUGH THE CRUST, AND TO THE SURFACE USING THE GEOCHEMISTRY OF ERUPTED MELTS AND MINERALS
Creator: Svoboda, Christopher
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Studies synthesizing field work, numerical simulations, petrology, geochemistry, and geophysical observations indicate that the compositional diversity of lavas results from evolution of mantle-derived basaltic magmas by mixing, assimilation, and fractional crystallization. These studies indicate this evolution occurs within dispersed complexes called transcrustal magmatic systems, rather than tank-like magma chambers. The processes within these magmatic systems have implications for...
Show moreStudies synthesizing field work, numerical simulations, petrology, geochemistry, and geophysical observations indicate that the compositional diversity of lavas results from evolution of mantle-derived basaltic magmas by mixing, assimilation, and fractional crystallization. These studies indicate this evolution occurs within dispersed complexes called transcrustal magmatic systems, rather than tank-like magma chambers. The processes within these magmatic systems have implications for understanding the evolution of continental crust, the breakup of continental landmasses, and the hazards associated with volcanism. We present three studies in various tectonic and magmatic settings, using the geochemistry of whole rocks and minerals to relate magmatic processes within transcrustal magma systems and their inputs from the mantle to large-scale plate tectonic and geodynamic questions. In a study of magnesium-rich andesites from the Taupo Volcanic Zone, I link primitive mineral compositions in Mg-depleted melts to the growth of magma accommodation zones in a rifting segment of arc crust. Mineral constraints on temperature and pressure indicate that the plumbing system first formed at mid- to lower-crustal pressures (3.5-7.0±2.8 kbar). I interpret the mafic mineralogy and presence of disequilibrium features as evidence that these andesites and their crystal cargo represent the products of a developing magmatic system in the middle to lower crust. This study addresses the question of how magmatic systems initially form and evolve. I examine lavas from the back arc of Patagonian Argentina, where volcanism is displaced from the magmatic arc due to subduction of oceanic spreading centers. I demonstrate using thermodynamic models that the source regions for melts contain volumes of pyroxenite (3-11%), and were generated at high pressures (2.6-2.7 GPa). These melting conditions have been consistent since the Eocene. I interpret these results as evidence of detachment of pyroxene-rich lithosphere that was created by magma-lithosphere interaction during the Mesozoic breakup of Gondwana. These results show a link between prior magmatic events the role of pyroxene-rich mantle lithologies in subsequent mantle melting episodes. Finally, I present a study that probes the evolution of late-stage magmas in the failed 1.1-billion-year-old Mid-Continent Rift that are analogous to packages of lava and sediment that are buried during the final stages of continental breakup. I present evidence showing magma mixing between primitive and evolved residual magma controls the magma composition in these lavas. The highly negative εHf and εNd isotopic characteristics of these magmas, supported by modeling outcomes, suggest extensive assimilation (15%) of continental crust accompanying fractional crystallization of olivine, plagioclase feldspar, and spinel at 4 kbar pressure and 1060° C. I interpret this as a renewed pulse of magma that has exploited a preexisting transcrustal magmatic system. I posit that this system had its magma supply exhausted at the end of the main stage of volcanism but remained partially molten due to residual heat from the main stage. The results of this study have implications for the persistence of these magmatic systems through time. Each individual study, while from disparate time periods and tectonic settings, demonstrates that the transcrustal magmatic system (and the transcrustal system’s link to the mantle) provides a suitable conceptual framework for modeling and describing the evolution of magmas. These systems are not static but rather change with time to respond to geodynamic forces and rates of magma delivery.
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Title: EFFICIENT AND PORTABLE SPARSE SOLVERS FOR HETEROGENEOUS HIGH PERFORMANCE COMPUTING SYSTEMS
Creator: Rabbi, Md Fazlay
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Sparse matrix computations arise in the form of the solution of systems of linear equations, matrix factorization, linear least-squares problems, and eigenvalue problems in numerous computational disciplines ranging from quantum many-body problems, computational fluid dynamics, machine learning and graph analytics. The scale of problems in these scientific applications typically necessitates execution on massively parallel architectures. Moreover, due to the irregular data access patterns and...
Show moreSparse matrix computations arise in the form of the solution of systems of linear equations, matrix factorization, linear least-squares problems, and eigenvalue problems in numerous computational disciplines ranging from quantum many-body problems, computational fluid dynamics, machine learning and graph analytics. The scale of problems in these scientific applications typically necessitates execution on massively parallel architectures. Moreover, due to the irregular data access patterns and low arithmetic intensities of sparse matrix computations, achieving high performance and scalability is very difficult. These challenges are further exacerbated by the increasingly complex deep memory hierarchies of the modern architectures as they typically integrate several layers of memory storage. Data movement is an important bottleneck against efficiency and energy consumption in large-scale sparse matrix computations. Minimizing data movement across layers of the memory and overlapping data movement with computations are keys to achieving high performance in sparse matrix computations. My thesis work contributes towards systematically identifying algorithmic challenges of the sparse solvers and providing optimized and high performing solutions for both shared memory architectures and heterogeneous architectures by minimizing data movements between different memory layers. For this purpose, we first introduce a shared memory task-parallel framework focusing on optimizing the entire solvers rather than a specific kernel. As most of the recent (or upcoming) supercomputers are equipped with Graphics Processing Unit (GPU), we decided to evaluate the efficacy of the directive-based programming models (i.e., OpenMP and OpenACC) in offloading computations on GPU to achieve performance portability. Being inspired by the promising results of this work, we port and optimize our shared memory task-parallel framework on GPU accelerated systems to execute problem sizes that exceed device memory.
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Title: HYALURONAN AS EFFECTIVE PLATFORMS FOR COMBINATORIAL CARBOHYDRATE DERIVATIVE GENERATION, AND FOR IMAGE-GUIDED SURGERY WITH SURFACE-ENHANCED RAMAN SPECTROSCOPY (SERS)
Creator: Liu, Kunli
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Hyaluronan (HA) is a polysaccharide consisting of repeating disaccharides of N-acetyl-D-glucosamine and D-glucuronic acid. HA plays important roles in a wide range of biological events. The principal endogenous receptor of HA, cluster of differentiation 44 (CD44), is overexpressed on many types of tumor cells as well as inflammatory cells in human bodies. HA-CD44 interactions are important in cell adhesion, cell migration, induction of hematopoietic differentiation, and signaling for cell...
Show moreHyaluronan (HA) is a polysaccharide consisting of repeating disaccharides of N-acetyl-D-glucosamine and D-glucuronic acid. HA plays important roles in a wide range of biological events. The principal endogenous receptor of HA, cluster of differentiation 44 (CD44), is overexpressed on many types of tumor cells as well as inflammatory cells in human bodies. HA-CD44 interactions are important in cell adhesion, cell migration, induction of hematopoietic differentiation, and signaling for cell activation. Other HA receptors include lymphatic vessel endothelial HA receptor-1 (LYVE-1), and HA receptor for endocytosis (HARE). HA is versatile for chemical modification or conjugation by exploiting the reactivity of carboxyl group, hydroxyl group, or the reducing end of the HA chain. Through chemical modification of HA, various kinds of self-assembled HA nanoparticles (HA-NPs) can be generated. There are increasing interests in utilizing HA-NPs for targeted imaging and therapy. Active targeting from HA-CD44 mediated interaction could lead to selective accumulation of HA-NPs at targeted disease sites. Chapter 1 is a review focusing on the synthesis strategies of self-assembled HA-NPs, as well as their applications in therapy and biomedical imaging. With the recognition of the importance of HA-CD44 interactions, there have been substantial efforts to develop novel compounds capable of binding with CD44 to modulate CD44 biology. Chapter 2 reports a novel approach for generating HA derivatives with enhanced CD44 binding. By modifying the carboxyl group on HA with various amine, aldehyde, and isocyanide moieties through the Ugi reaction, 36 HA like polysaccharides were generated. Two lead compounds were identified with enhanced CD44 binding from the polysaccharide library compared to unmodified HA, which was confirmed by surface plasmon resonance and cellular studies. Ski-learn as a machine learning tool was utilized to analyze the library of binding data and yield prediction with an accuracy over 80%. In conclusion, modification of HA via the Ugi reaction can be a promising approach to develop novel binders toward CD44. While HA has been frequently employed as the targeting molecule in imaging via near infrared (NIR) or magnetic resonance (MRI) imaging, the potential of HA for surface-enhanced Raman spectroscopy (SERS) imaging has not yet been explored. SERS NPs are well-known for strong multiplexing capability, since different flavors of SERS NPs can be synthesized using different SERS dyes, resonant or non-resonant dye. SERS NPs are a promising tool for tumor margin removal in image-guided surgery. However, there are several challenges associated with SERS NPs for cancer imaging: 1) reproducible synthesis of SERS NPs; 2) ligand attachment for SERS NPs. Chapter 3 addresses these two issues by: 1) developing a reproducible protocol for 50 nm SERS NPs with low-femtomolar detection sensitivity; 2) employing liposome as the bridge for HA attachment to SERS NPs. The resulting HA-liposome SERS NPs have been successfully applied in imaging guided surgical removal of breast cancer in a spontaneous mouse breast cancer model.
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Title: (de)(anti)(intra) : Queer Self-Storying as Embodied, Community, and Theory-Building Processes
Creator: de Sostoa-McCue, Tania
Date: 2022
Collection: Electronic Theses & Dissertations
Description: This cultural rhetorics project asserts that story is theory, and surfaces self-storying as an embodied, theory-building process. I undertook phased interviews with three queer creative writers, holding space for their stories in order to witness, interact with and to learn from the ways in which queer authors discuss and approach relationships with one another through storying and composing. This desire to learn from other queer-identified community stakeholders led to the emergence of a...
Show moreThis cultural rhetorics project asserts that story is theory, and surfaces self-storying as an embodied, theory-building process. I undertook phased interviews with three queer creative writers, holding space for their stories in order to witness, interact with and to learn from the ways in which queer authors discuss and approach relationships with one another through storying and composing. This desire to learn from other queer-identified community stakeholders led to the emergence of a story-theory, through which a narrative thread of failure, survival and agency emerged. I articulate a reorientation and reframing of guiding concepts of community, composition and embodiment within queer spaces as (intra)community, (de)composition, and the (anti)body. An important impetus for this project was a desire to address the future of Queer in the academy. I utilize tools and theories from queer theory and cultural rhetorics not only to build, but to show spaces in which these conceptual frames can inform future, positive shifts. I do so to provide my own insights and to offer tools to continue the work Queer in the academy and to bridge the space between academic Queer and non-academic queer. I utilize cultural rhetorics to continue the work of what I see as one of Queer’s primary purposes: to subvert, to disrupt and to re-imagine the ways in which the queer community and Queer can thrive and effect systemic change.
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Title: Essays in Labor Economics
Creator: VanderBerg, Bryce Scott
Date: 2022
Collection: Electronic Theses & Dissertations
Description: This dissertation consists of two empirical studies and one applied theoretical study in labor economics. In the first chapter, I study the extend to which an observed layoff is used by employers to infer a worker's unobserved ability early in their labor market career. In the second chapter, I develop a theoretical model of wage dynamics that extends the employer learning and statistical discrimination model of Altonji and Pierret (2001) to allow for discrete changes in observable...
Show moreThis dissertation consists of two empirical studies and one applied theoretical study in labor economics. In the first chapter, I study the extend to which an observed layoff is used by employers to infer a worker's unobserved ability early in their labor market career. In the second chapter, I develop a theoretical model of wage dynamics that extends the employer learning and statistical discrimination model of Altonji and Pierret (2001) to allow for discrete changes in observable characteristics. In the third chapter, which is joint work with Gabrielle Pepin at the W.E. Upjohn Institute, we study the contribution of occupational sorting and mismatch to child penalties in the United States. I: The Signaling Role of Early Career Job LossI examine the extent to which ability signaling explains long-term wage losses suffered by young workers who experience layoffs. Young workers are of particular interest because employers have limited information about their ability, so signaling theoretically plays a larger role in determining wages. In addition, young workers are unlikely to experience wage losses due to loss of industry-specific human capital or separation from high-quality job matches, which may explain long-term wage decreases among older workers. Using data from the National Longitudinal Survey of Youth 1997, I show that young workers of all ability levels initially experience similar wage losses following layoffs, but high-relative ability workers fully recover within five years while low-relative ability workers experience persistent wage losses. Consistent with traditional learning models, relative, not actual, ability affects wage trajectories. I illustrate a conceptual model of layoff signaling that varies by pre-layoff experience and can explain divergent wage trajectories across high- and low-relative ability workers. I test the model empirically and find that low-relative ability workers' inability to overcome negative layoff signals explains a substantial proportion of long-term wage losses among young workers. Employer learning effects vary by race and gender.II: Employer Learning and Statistical Discrimination with Unexpected InformationThe Employer Learning and Statistical Discrimination (EL-SD) model of Altonji and Pierret (2001) assumes that employers learn about a worker's unobserved ability in a smooth, continuous manner, holding observable characteristics constant. In practice, observable characteristics, such as years of education, often change discretely over time for many workers. I extend the EL-SD model to allow for changes in observable characteristics to influence an employer's belief about a worker's ability. I show that changes in observable characteristics that are correlated with ability lead to discrete changes in employers' beliefs about the worker's ability, interrupting the smooth, continuous employer learning processes described in the EL-SD model. I further show that this discrete change in employer learning is larger for workers early in their labor market career, with the effect diminishing as labor market experience increases. I then use data from the NLSY97 to empirically test these predictions in the context of the signaling role of returning to school. I find suggestive evidence that returning to school to receive a GED or graduate degree sends a positive ability signal to the labor market, while returning to school to receive an associate or bachelor's degree does not.III: Occupational Sorting, Multidimensional Skill Mismatch, and the Child Penalty among Working MothersWe study the extent to which occupational sorting explains child penalties---gender gaps in labor market outcomes due to children---among working parents. Using an event-study approach and data from the National Longitudinal Surveys of Youth (NLSY) 1979 and 1997, we estimate that children generate long-run earnings gaps of over \$200 per week among working parents. In the NLSY79, we find that children lead mothers to sort into lower-paying occupations in which employees tend to work fewer hours. We estimate that children increase multidimensional occupation-skill mismatch among working mothers by 0.3 standard deviations, relative both to their own levels of mismatch from before birth and to those of fathers. In the NLSY97, results suggest that improvements in labor market outcomes among fathers in response to children, rather than a worsening of labor market outcomes among mothers, seem to drive child penalties.
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Title: Trade, Finance & the Macroeconomy
Creator: Rowe, Nicholas
Date: 2022
Collection: Electronic Theses & Dissertations
Description: This paper investigates the effects of financial development on firm export when lenders specialize in lending against different borrower activities. Using Italian microdata on manufacturing firms, we document that financial development driven by locally-focused banks can boost export participation but can depress the export sales of incumbent exporters. We explain these patterns through an industry equilibrium model of international trade with heterogeneous firms and banks. Locally-focused...
Show moreThis paper investigates the effects of financial development on firm export when lenders specialize in lending against different borrower activities. Using Italian microdata on manufacturing firms, we document that financial development driven by locally-focused banks can boost export participation but can depress the export sales of incumbent exporters. We explain these patterns through an industry equilibrium model of international trade with heterogeneous firms and banks. Locally-focused financial development eases the entry of credit-rationed firms into export by increasing the pledgeability of their domestic inventory assets; however, it also induces credit-satiated exporters to partly redirect their production capacity to domestic markets. Model calibration reveals that when financial development is too local, increased domestic output and export participation can come at the cost of reduced aggregate exports.
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Title: EXPERIMENTAL ANALYSIS AND MODEL DEVELOPMENT OF DUAL MODE, TURBULENT JET IGNITION (DM-TJI) ENGINE OPERATING WITH GASOLINE AND ALTERNATIVE FUELS
Creator: Ayele, Yidnekachew Messele
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Gasoline fuel is the most convenient energy source for light-duty vehicles in energy density and refueling time. However, the emission regulations for internal combustion engines force the industry to exploit innovative combustion technologies. The spark-ignition engine was forced to be cleaner and more efficient, changing from regular combustion engines to a more advanced internal combustion engine and electrification. The current scenario shows that automotive companies and researchers are...
Show moreGasoline fuel is the most convenient energy source for light-duty vehicles in energy density and refueling time. However, the emission regulations for internal combustion engines force the industry to exploit innovative combustion technologies. The spark-ignition engine was forced to be cleaner and more efficient, changing from regular combustion engines to a more advanced internal combustion engine and electrification. The current scenario shows that automotive companies and researchers are exploring hybrid powertrains with advanced internal combustion engine technologies with electrification or pure electric vehicles. The Dual Mode, Turbulent Jet Ignition (DM-TJI) system is one of the promising advanced combustion systems, powered by active air/fuel scavenging pre-chamber ignition systems. The distributed ignition sites created by the pre-chamber flames improve the combustion engine's efficiency, simultaneously mitigating combustion knock at a high engine compression ratio and enabling lean-burn or high level of external EGR dilution operation. This study analyzes the performance of a single-cylinder DM-TJI metal engine with gasoline and alternative fuels. The first part of the study presents the experimental investigations on three pre-chamber nozzle orifice diameters at various engine speeds and 10 bar engine load. The combustion parameters for each tested orifice diameter are presented for the incremental engine speeds. A numerical analysis was conducted using the GT-Power model simulation tool to support the experimental result. The DM-TJI engine's maximum gross indicated efficiency was examined and found to be 44.56%, with a higher EGR dilution rate of 45%. This orifice diameter study reported on the first published results of the desertion. Additional experimental data were collected for the selected orifice diameter at a wide range of engine operating test matrices. A predictive engine model was introduced with experimental data validation. The experimental data and predictive model generated the engine performance and fuel map for a real-world fuel economy study. Conventional and hybrid powertrain vehicles were developed with GT-Suite commercial software. Each powertrain model was calibrated in terms of components (battery, electric motors) capacity, internal combustion engine operative points, energy management strategy, and gear ratios with chassis dynamometer measured data of the vehicle drive cycle. A selected U.S. Environmental Protection Agency (EPA) driving schedule was implemented on the GT-Suite powertrain. The DM-TJI engine drive cycle fuel economy is compared to an industry-based conventional vehicle with the same powertrain except for the engine map. The results show the DM-TJI engine fuel economy improvement between 10.5%-17.29% and CO2 emissions reductions between 9.51%-14.75% for the selected driving schedule. Mild and parallel hybrid powertrain further improve the fuel economy by 9.23% and 29.88%, respectively, compared to the conventional powertrain of the DM-TJI engine. The CO2 emission was reduced by 23%. Finally, the single-cylinder DM-TJI metal engine performance under different alternative fuels was studied. An experimental test was carried out at stoichiometric conditions with different fuels, engine speed, engine load, and EGR dilution rates. Compared to gasoline fuel, E80 ethanol blend fuel produces 4.47% less CO2 and 25.75% less CO emission, and methane fuel produces 27.91% less CO2 and 57.85% less CO emission. E80 ethanol blend has the highest indicated efficiency of 45.61% with 45% EGR dilution. Methane fuel has a maximum indicated efficiency of 45.03% with 38.5% EGR dilution.
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Title: TEACHERS’ BELIEFS, PERCEPTIONS, EXPERIENCES, AND STRATEGIES IN TEACHING AND ENGAGING MULTILINGUAL LEARNERS IN MATHEMATICS CLASSROOMS
Creator: Kursav, Merve Nur
Date: 2022
Collection: Electronic Theses & Dissertations
Description: The number of Multilingual Learners (MLs) enrolled in U.S. schools increased from 8.1% of the total student population to more than 10% between the 2000-2001 school year and the 2016-2017 school year (NCELA, 2016; U.S. Dept. of Education, NCES, 2020). Like all learners, MLs need support to ensure their engagement in mathematics classrooms (Kena et al., 2015; Silva & Kucer, 2016). While the number of MLs has been increasing, there has been limited research about how teachers support these...
Show moreThe number of Multilingual Learners (MLs) enrolled in U.S. schools increased from 8.1% of the total student population to more than 10% between the 2000-2001 school year and the 2016-2017 school year (NCELA, 2016; U.S. Dept. of Education, NCES, 2020). Like all learners, MLs need support to ensure their engagement in mathematics classrooms (Kena et al., 2015; Silva & Kucer, 2016). While the number of MLs has been increasing, there has been limited research about how teachers support these students’ engagement in content area classrooms (Hos, 2016). A notable paucity of studies focuses specifically on mathematics teachers’ experiences supporting MLs’ learning and engagement in mathematics classrooms (Warren et al., 2014). This study investigated mathematics teachers' beliefs, perceptions, experiences, and strategies in teaching and engaging MLs in 6th -12th grade mathematics classrooms. The dissertation study contributes to the field of mathematics education by providing practical and theoretical implications.This dissertation is built on an extensive review of the relevant literature about 6th-12th-grade mathematics teachers’ beliefs, perceptions, and experiences in teaching and engaging MLs in the mathematics classroom. I used a combination of Teacher Cognition (TC) and Culturally Responsive Teaching (CRT) as the theoretical framework. Mixed methods were used, and data were collected in two phases: (1) quantitative data (i.e., adapted survey using Karabenick and Noda’s (2004) survey and Rhodes’s (2017) CRT survey) and (2) qualitative data (i.e., teacher interviews). Results revealed that teachers frequently used appropriate materials, instructional resources, standards, objectives, scaffolding strategies (e.g., grouping, pacing, wait time, transparency in teaching, comprehensible input), and assessment tools to support MLs’ learning and engagement in the mathematics classroom. Data sources clearly illustrated that teachers strongly agreed they were comfortable with having MLs in their classroom and were willing to support MLs in learning mathematics by boosting their engagement. The results also showed that teachers needed to (1) learn and design strategies for academic support of MLs, (2) learn about the systematic school and district resources available to support for MLs’ identification and placement; (3) learn about district and school-level supports available at the administrator level; (4) make data-driven decisions about curriculum and instruction for MLs; (5) have more willingness to work with MLs; (6) have professional development and support for culturally responsive teaching and MLs' learning and engagement; (7) notice their beliefs about language acquisition (bilingualism and translanguaging); (8) establish inclusion; (9) encourage autonomy and cultural awareness of students and collaborative decision making with all; (10) establish trust and relationships; and (11) provide transparent feedback and assessment. It is believed that the results of the study will help teachers of MLs to comprehend the prominence of culturally responsive teaching. Additionally, implications include advising policymakers to acknowledge that covering the curriculum in a timely manner for MLs is not enough for sustained success.
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Title: Environmental Microbial Surveillance : From Source Tracking in Watersheds to Pathogen Monitoring in Sewersheds
Creator: Flood, Matthew Thomas
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Understanding of the connections between water and health, through the use of water quality monitoring, surveys and surveillance, can help to address the impacts of anthropomorphic changes on the environment. This study sought to understand these connections through the water quality monitoring within watershed basins as well as pathogen surveillance within sewersheds. Specifically, this dissertation sought to 1) understand the sources of pollution and their connections with land use in the...
Show moreUnderstanding of the connections between water and health, through the use of water quality monitoring, surveys and surveillance, can help to address the impacts of anthropomorphic changes on the environment. This study sought to understand these connections through the water quality monitoring within watershed basins as well as pathogen surveillance within sewersheds. Specifically, this dissertation sought to 1) understand the sources of pollution and their connections with land use in the various subsections of watersheds; 2) to find a cost-effective way to surveil the spread of SARS-CoV-2 using wastewater surveillance; and 3) to understand the differences in wastewater surveillance between communities. Water quality monitoring using microbial source tracking (MST) was performed with a survey of five mixed-use watersheds in Michigan. Through the use of spatial clustering, it was found that temporal contamination was primarily driven by precipitation and its associated variables (e.g., streamflow, turbidity, overland flow), while spatial contamination is driven by land uses (e.g., septic tank density, tile drain proportions, and tillage). Additionally, porcine fecal contamination was more often correlated with nutrients in streams than either bovine or human contamination. The development of a cost-effective workflow for the detection and quantification of SARS-COV-2 in wastewater was undertaken. Wastewater from communities around Michigan were collected and analyzed along with viral surrogates for SARS-CoV-2 to investigate different workflow options. The Pseudomonas phage Phi6 was seeded in different wastewater matrices to test concentration and recovery by ultrafiltration-based method and polyethylene glycol (PEG) precipitation. The PEG method provided better virus recovery than the ultrafiltration-based methods as measured using RT-ddPCR. The comparison of two communities (A and B) wastewater results for SARS-CoV-2 analyzed against case data was undertaken. These results were significantly correlated with cases in both communites, but the level of correlation differed based on spatial (e.g., zipcode vs county level cases) and temporal (e.g., date of symptom(s) onset vs. the referral date for cases) resolution. Wastewater surveillance was more representative of higher spatial resolution (zipcode data) of cases in both communities. When examining the temporal resolution of the communities, community B’s wastewater results were more closely tied to the onset of symptoms and not the case referral date. The ability to monitor indicators of pollution in watersheds and surveil etiological agents of disease in sewersheds provide non-intrusive methods for evaluating the potential risks and current burdens to community health. The first part of the work could be considered “downstream” monitoring identifying sources and potential exposures with the goal of reducing waterborne disease. While “upstream” monitoring was used for identifying the disease trends in the community and was focused on public health measures to prevent transmission. This project contributed novel methods, results and analysis providing valuable knowledge ultimately addressing the role of monitoring strategies to protect public health.
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Title: Application of density functional theory in nuclear structure
Creator: Li, Tong
Date: 2022
Collection: Electronic Theses & Dissertations
Description: The nuclear density functional theory (DFT) is a microscopic self-consistent framework suitable for describing heavy nuclei and performing large-scale studies. In this dissertation I discuss my research works on the development and application of the Skyrme nuclear-DFT framework, covering a broad range of topics, including the nucleon localization in rotating systems, the origin of reflection-asymmetric deformations, the parameter calibration for beta decays, and the development of a new...
Show moreThe nuclear density functional theory (DFT) is a microscopic self-consistent framework suitable for describing heavy nuclei and performing large-scale studies. In this dissertation I discuss my research works on the development and application of the Skyrme nuclear-DFT framework, covering a broad range of topics, including the nucleon localization in rotating systems, the origin of reflection-asymmetric deformations, the parameter calibration for beta decays, and the development of a new coordinate-space DFT solver.The nucleon localization function (NLF), discussed in the first part, is a useful tool for the visualization of structure information. It has been utilized to characterize clustering and shell structure. How the NLF pattern evolves in rotating systems, how it visualizes internal nuclear structure, and how it is connected with single-particle (s.p.) orbits are discussed in this dissertation. The second part deals with nuclei having reflection-asymmetric shapes, which are important candidates for the search of permanent electric dipole moments. In this dissertation, the origin of pear-like deformation is investigated through both the multipole expansion of the energy density functional and the spectrum of canonical s.p. states. Theoretical predictions of beta-decay rates are discussed next; they are important for r-process simulations that involves nuclei whose experimental beta-decay data are unknown. To provide reliable predictions with quantified uncertainties, the χ^2 optimization is performed to constrain parameters that significantly affect beta-decay transitions in proton-neutron finite-amplitude-method calculations. Besides a well calibrated functional, a reliable and efficient DFT solver is also crucial. The Hartree-Fock-Bogoliubov (HFB) method in the coordinate space is preferred for deformed and weakly bound nuclei, as solvers based on basis expansions often have difficulty correctly describing continuum effects. A new HFB solver based on the canonical-basis HFB formalism in the three-dimensional coordinate space is developed in this dissertation. It is a well parallelized solver and has been carefully benchmarked against other established HFB solvers.
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Title: STUDENTS’ CONCEPTIONS OF THEIR CAMPUS LGBTQ+ CENTER
Creator: Noble, Chelsea E.
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Lesbian, gay, bisexual, transgender, queer, and similar identities (LGBTQ+) resource centers on college campuses provide services, resources, programming, and advocacy focused on gender and sexuality, especially minoritized genders and sexualities. As center staff enact this work at the individual and organizational levels, LGBTQ+ centers seek to promote students’ thriving, especially among students with minoritized genders and sexualities. Although students are the animating reason for LGBTQ...
Show moreLesbian, gay, bisexual, transgender, queer, and similar identities (LGBTQ+) resource centers on college campuses provide services, resources, programming, and advocacy focused on gender and sexuality, especially minoritized genders and sexualities. As center staff enact this work at the individual and organizational levels, LGBTQ+ centers seek to promote students’ thriving, especially among students with minoritized genders and sexualities. Although students are the animating reason for LGBTQ+ centers’ existence, relatively little is known about how students experience and conceptualize campus LGBTQ+ resource centers. The purpose of this study was to understand LGBTQ+ resource centers from students’ perspectives. Guided by a critical adaptation of an ecological model of development (Bronfenbrenner, 1993; Renn & Arnold, 2003), I undertook a qualitative study drawing on interviews with 15 students who felt in some way connected to their campus LGBTQ+ center. I also included data from observations and publicly available center documents. The participants were all current students at a Midwestern university where the LGBTQ+ center had at least one full-time staff member and a clear commitment to social justice. The campus LGBTQ+ center often served as an important force in students’ ecosystems. Students’ ecosystems reflected common elements of university education (e.g., classes, student organizations, and friends), LGBTQ+ campus spaces, families and communities of origin, as well as broader forces including U.S. politics, the COVID-19 pandemic, and a number of oppressive systems. In the midst of highly variable, often unsupportive, and sometimes hostile contexts, students found support and guidance through their LGBTQ+ center. Students experienced their center in five major ways: physical space, source of relationships, organizational navigation and tools, virtual presence, and symbol of institutional commitment. Students emphasized and interacted with each of these aspects in accordance with their needs as they navigated their academic pursuits and daily lives in the face of racism, cissexism, heterosexism, and a host of other oppressive forces. Ultimately, students’ experiences with their campus LGBTQ+ center were frequently a means of survival and a boost towards students thriving on campus and in their lives.
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Title: EXPERIMENTAL INVESTIGATIONS OF Al-BASED INITIATIOR FOR (CO)POLYMERIZATION OF EPOXIDES AND EPISULFIDE AND APPLICATION TOWARD MEMBRANE SYNTHESIS
Creator: Safaie Ashtiani, Niloofar
Date: 2022
Collection: Electronic Theses & Dissertations
Description: We developed a novel aluminum-based initiator for epoxide polymerization which facilitated polymerization of various epoxides (epichlorohydrin, propylene oxide, etc.) and episulfide up to molecular weights of 100 kg/mol while maintaining relatively narrow polydispersity (Ð < 1.3). The initiator was simply synthesized through the reaction of a thiol ligand and trialkyl aluminum, with the thiol ligand choice enabling polymer end group control. Copolymerization of epichlorohydrin and propylene...
Show moreWe developed a novel aluminum-based initiator for epoxide polymerization which facilitated polymerization of various epoxides (epichlorohydrin, propylene oxide, etc.) and episulfide up to molecular weights of 100 kg/mol while maintaining relatively narrow polydispersity (Ð < 1.3). The initiator was simply synthesized through the reaction of a thiol ligand and trialkyl aluminum, with the thiol ligand choice enabling polymer end group control. Copolymerization of epichlorohydrin and propylene oxide and copolymerization of different epoxides with episulfide demonstrated the ability of this method to control polymer architecture. We further investigated the effect of catalyst concentration and initiator structure on the kinetics of epoxide polymerizations through 1H NMR spectroscopy. Finally, we combined our method of polymerization with another facile method, reversible addition fragmentation with chain transfer (RAFT) polymerization, to synthesize block-co-polymers made from vinyl and epoxide monomers. To do this, we made a macroinitiator from polystyrene (PS) and poly(methyl methacrylate) (PMMA), synthesized by RAFT polymerization, and further polymerized epoxide from it. Therefore, this new synthetic tool allows for the facile and controlled polymerization of epoxides into well-defined, functional, polyether materials. Furthermore, the introduced innovative and reliable methodology for the synthesis of SAl initiators enabled us to tune the polymer architecture to readily access more complex structure of polyepisulifides. We synthesized di-functional (d-H) and tetra-functional (t-H) SAl initiators to produce ABA and star-(co)polymers consisting of propylene sulfide and PO or ECH. Finally, polyethylene glycol (PEG) was used as a macroinitiator to create PEG-b-PPS block copolymers and characterized by 1H, 13C NMR spectroscopy, DOSY, DSC, and SEC. Motivated by the result, we prepared the star shape cross linked membrane from t-H initiator. The composition was controlled through the monomer feed ratio of propylene oxide (PO) and epichlorohydrin (ECH) for synthesis of PPO-PECH membrane in the presence of poly(ethylene oxide)-diglycidyl ether as a cross linker and the most optimized PPO-PECH with the ratio of 90:10 resulted optically clear and flexible film. We further modified the membrane with a range of amines like trimethylamine (TEA), dimethylamine (DMA), triethylamine (TEA), and diethylamine (DEA) by membrane dipping method. The chemical, physical, and mechanical properties of resultant secondary amine grafted and quartenized membranes were characterized as a candidate for CO2 transport. Moreover, we designed the facilitated transport membranes of crosslinked ether-based PPO-PECH membranes with the range of hindered and unhindered primary amines using previously reported mono(μ-alkoxo)- bis(alkylaluminum) (MOB). The physical and chemical properties of the membranes investigated by FT-IR spectroscopy, DSC, TGA, and rheology. This method demonstrated a simple and robust strategy to prepare copolymers cross linked membranes containing amines for CO2 transport. This enables us to compare the effect of different amines in the structure of facilitated transport membranes. In this thesis research we seek to develop a SAl initiator as a platform that is both simple to use and can synthesize new polymeric materials. This methodology is simple and tunable to produce robust crosslinked membranes for molecu
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Title: UNDERSTANDING THE IMPACT OF SEXUAL ASSAULT RELATED SOCIAL MEDIA CONTENT ON SURVIVORS : AN EXPLORATORY SEQUENTIAL MIXED METHODS STUDY
Creator: PettyJohn, Morgan E.
Date: 2022
Collection: Electronic Theses & Dissertations
Description: In recent years, hashtag activism movements (i.e., using a common message or phrase to unite user voices to address injustice; Yang & Kaun, 2016) have unfolded across social media (SM) platforms to bring attention to the prevalence and impacts of sexual assault. Specifically, the online #MeToo Movement went viral around the world in 2017, resulting in increased news coverage and public discourse surrounding this topic (Anderson & Toor, 2018). Indeed, nearly half (44%) of women in the United...
Show moreIn recent years, hashtag activism movements (i.e., using a common message or phrase to unite user voices to address injustice; Yang & Kaun, 2016) have unfolded across social media (SM) platforms to bring attention to the prevalence and impacts of sexual assault. Specifically, the online #MeToo Movement went viral around the world in 2017, resulting in increased news coverage and public discourse surrounding this topic (Anderson & Toor, 2018). Indeed, nearly half (44%) of women in the United States experience unwanted sexual contact in their lifetime (Smith et al., 2018) and these violations are associated with increased risk for negative mental health outcomes, including depression, anxiety, and posttraumatic stress disorder (PTSD; Mason & Lodrick, 2013). After experiencing interpersonal violence, reminders of the trauma (e.g., words, images) can trigger psychophysiological reactions for survivors, such as emotional dysregulation, physical symptoms (e.g., heart racing), and increases in adverse mental health symptomatology (Mchugo et al., 2001; Moser et al., 2015). Given the popularity of SM among women in the U.S. (78% report usage; Pew Research Center, 2019), survivors of sexual assault are presumably being exposed to trauma related content connected to popular hashtag activism movements while spending time online. However, little is known about how exposure to sexual assault narratives and related discourse in this context could impact the mental health and relationships of survivors.The present study aims to address this gap in the literature by using an exploratory sequential mixed methods design to better understand survivors’ online experiences during this unique cultural moment. The qualitative strand of the study utilized thematic analysis of semi-structured interviews (n = 12) to explore the lived experiences of young women survivors (18-34 years old) using SM since initiation of the #MeToo Movement. Survivors described adverse changes in their mental health during periods of intense media coverage relating to sexual assault stories (e.g., Dr. Christine Blasey Ford’s Senate testimony). Some survivors also reported negative changes in their personal relationships with people in their life based on how they discussed sexual assault on these platforms. Findings from the qualitative strand were used to inform development of an online, cross-sectional quantitative survey, facilitated through CloudResearch’s MTurk toolkit. Multiple regression analyses found general SM use, exposure to sexual assault content, and exposure to unsupportive attitudes (i.e., victim blaming or perpetrator supporting) to be significantly predictive of depression, anxiety, and PTSD symptomatology among young women, both survivors (n = 312) and non-victims (n = 171). Survivors reported noticing people from their support systems (e.g., family, friends, co-workers) posting unsupportive attitudes about other victims’ stories at significantly higher rates than non-victims. Findings from the present study implore clinicians to assess SM use and level of exposure to sexual assault related content among clients, particularly those who have experienced sexual assault. Further, clinicians should stay informed about viral news stories and hashtag activism movements addressing sexual assault and provide space for clients to process this content during times of high saturation on SM platforms.
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Title: DIVERSIFYING AGRICULTURAL LANDSCAPES FOR BIODIVERSITY AND ECOSYSTEM SERVICES
Creator: Kemmerling, Lindsey Renee
Date: 2022
Collection: Electronic Theses & Dissertations
Description: This dissertation focuses on strategies to restore biodiversity and ecosystem services in agricultural landscapes through diversifying the plant community at the landscape level. Biodiversity and ecosystem services are declining globally, and a leading cause of this decline is large-scale row crop agriculture which results in habitat loss and pollution. Simultaneously, the human population is growing, as are human demands for resources produced by agriculture. Diversifying agricultural...
Show moreThis dissertation focuses on strategies to restore biodiversity and ecosystem services in agricultural landscapes through diversifying the plant community at the landscape level. Biodiversity and ecosystem services are declining globally, and a leading cause of this decline is large-scale row crop agriculture which results in habitat loss and pollution. Simultaneously, the human population is growing, as are human demands for resources produced by agriculture. Diversifying agricultural landscapes is one method to both mitigate the loss biodiversity while providing essential human resources. I conducted three studies that test if diversifying cropping systems can increase biodiversity and ecosystem services and maintain or even increase agricultural yield. In Chapter 1, I tested the ability of multiple native, perennial bioenergy crops (alternatives to annual bioenergy crops) to provide both crop yield and conserve pollinators. I measured pollinator abundance and species richness, flower abundance and species richness, and crop yield across four native perennial biofuel crop varieties: successional land (unmanaged), restored prairie, a mix of native grasses, and seeded switchgrass. Successional land had the most diverse community of pollinators but the lowest crop yield, native grasses had the highest yield but the least diverse pollinator community, and switchgrass and restored prairie were intermediate. If both pollinator conservation and crop yield are valued similarly, restored prairie was the optimal biofuel crop. Chapter 2 tested the effects of crop management practices in row crop agriculture, including the establishment of a conservation practice called “prairie strips” on biodiversity and ecosystem services. Prairie strips are strips of farmland retired from production and actively restored with native prairie plant species. I synthesized the tradeoffs and synergies of a suite of biodiversity and ecosystem service measures across a land use intensity gradient, as well as their spillover from prairie strips into cropland. The lowest land use intensity consistently had the highest levels of biodiversity and ecosystem services other than crop yield. Treatments with prairie strips had higher pollination services and a higher abundance of butterflies and spiders than other row crop treatments. Crop yield in a treatment with low land use intensity and prairie strips remained as highest land use intensity treatment, even when including the area taken out of production for prairie strips. Biodiversity and ecosystem services decreased with increasing distance from prairie strips and this effect was more pronounced in the second year of the prairie strips than the first for several measures. These results show that, even in early establishment, prairie strips can contribute to the conservation of biodiversity and ecosystem services without a disproportionate loss of crop yield. Chapter 3 further investigated one of the measures addressed in Chapter 2: butterfly biodiversity. I measured butterfly and plant species richness and abundance across three years in the same land use intensity gradient. Butterfly abundance and richness increased as land use intensity decreased. Prairie strips harbored unique butterfly communities and had a higher abundance of butterflies than other row crop treatments, including conservation land. Across the 1 ha plot of which 5% was prairie strip, butterfly abundance was higher in row crops with prairie strips than in row crops without prairie strips, likely as a result of prairie strips and other crop management practices in treatments with prairie strips, such as reduced pesticides. Altogether, this work presents evidence that restoring habitat within farms can support biodiversity and ecosystem services without disproportionately impacting crop yields. Furthermore, when strategically placed, these conservation strategies can prevent unnecessary greenhouse gas emissions, and potentially increase crop yield.
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