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- Genre: Doctoral Dissertation
- Genre: Case studies
- Creators: Arizona State University
Description
Primary producers, from algae to trees, play a pivotal role in community structure and ecosystem function. Primary producers vary broadly in their functional traits (i.e., morphological, physiological, biochemical, and behavioral characteristics), which determine how they respond to stimuli and affect ecosystem properties. Functional traits provide a mechanistic link between environmental conditions, community structure, and ecosystem function. With climate change altering environmental conditions, understanding this mechanistic link is essential for predicting future community structure and ecosystem function. Competitive interactions and trait values in primary producers are often context dependent, whereby changes in environmental conditions and resources alter relationships between species and ecosystem processes. Well-established paradigms concerning how species in a community respond to each other and to environmental conditions may need to be re-evaluated in light of these environmental changes, particularly in highly variable systems. In this dissertation, I examine the role of primary producer functional traits on community structure and ecosystem function. Specifically, I test a conceptual framework that incorporates response traits, effect traits, and their interaction, in affecting primary producer communities and ecosystem function across different aquatic systems. First, I identified species-specific responses to intensifying hydrologic stressors important in controlling wetland plant community composition over time in an aridland stream. Second, I found that effect traits of submerged and emergent vegetation explained differences in ecosystem metabolism and carbon dynamics among permafrost mire thaw ponds. Next, I examined response-effect trait interactions by comparing two dominant wetland plant species over a water-stress gradient, finding that responses to changes in hydrology (i.e., altered tissue chemistry) in turn affect ecosystem processes (i.e., subsurface CO2 concentration). Finally, I demonstrate how indirect effects of diatom functional traits on water chemistry and ecosystem metabolism help explain disconnects between resource availability and productivity in the Colorado River. By expanding my understanding of how metabolic processes and carbon cycling in aquatic ecosystems vary across gradients in hydrology, vegetation, and organic matter, I contributed to my understanding of how communities influence ecosystem processes. A response-effect trait approach to understanding communities and ecosystems undergoing change may aid in predicting and mitigating the repercussions of future climate change.
ContributorsLauck, Marina Diane (Author) / Grimm, Nancy B (Thesis advisor) / Appling, Alison P (Committee member) / Childers, Dan E (Committee member) / Sabo, John L (Committee member) / Arizona State University (Publisher)
Created2022
Description
Science can help inform policy decisions by providing information on the risks and benefits of a technology. In the field of nanotechnology, which is characterized by high degree of complexity and uncertainty, there are high demands for scientists to take an active role in policy debates with regulators, policy-makers and the public. In particular, policy-makers often rely on scientific experts to help them make decisions about regulations. However, scientists’ perceptions about policy and public engagement vary based on their individual characteristics, values, and backgrounds. Although many policy actors are involved in nanotechnology policy process, there are few empirical studies that focus on the establishment of coalitions and their impact on policy outputs, as well as the role of scientists in the coalitions. Also, while the Environmental Protection Agency (EPA) has regulatory authority over nanoscale materials, there is a lack of literature that describes the use of science on EPA’s decision making of nanotechnology.
In this dissertation, these research gaps are addressed in three essays that explore the following research questions: (1) how are nano-scientists’ individual characteristics and values associated with their perceptions of public engagement and political involvement? (2) how can the Advocacy Coalition Framework (ACF) can be applied to nanotechnology policy subsystem? and (3) how does the EPA utilize science when making regulatory decisions about nanotechnology? First, using quantitative data from a 2011 mail survey of elite U.S. nanoscientists, the dissertation shows that scientists are supportive of engaging with policy-makers and the public about their results. However, there are differences among scientists based on their individual characteristics. Second, qualitative interview analysis suggests that there are two opposing advocacy groups with shared beliefs in the nanotechnology policy subsystem. The lineup of coalition members is stable over time, while the EPA advocates less consistent positions. The interview data also show a significant role of scientific information in the subsystem. Third, the dissertation explains the EPA’s internal perspective about the use of science in regulatory decision making for nanotechnology. The dissertation concludes with some lessons that are applicable for policy-making for emerging technologies.
In this dissertation, these research gaps are addressed in three essays that explore the following research questions: (1) how are nano-scientists’ individual characteristics and values associated with their perceptions of public engagement and political involvement? (2) how can the Advocacy Coalition Framework (ACF) can be applied to nanotechnology policy subsystem? and (3) how does the EPA utilize science when making regulatory decisions about nanotechnology? First, using quantitative data from a 2011 mail survey of elite U.S. nanoscientists, the dissertation shows that scientists are supportive of engaging with policy-makers and the public about their results. However, there are differences among scientists based on their individual characteristics. Second, qualitative interview analysis suggests that there are two opposing advocacy groups with shared beliefs in the nanotechnology policy subsystem. The lineup of coalition members is stable over time, while the EPA advocates less consistent positions. The interview data also show a significant role of scientific information in the subsystem. Third, the dissertation explains the EPA’s internal perspective about the use of science in regulatory decision making for nanotechnology. The dissertation concludes with some lessons that are applicable for policy-making for emerging technologies.
ContributorsKim, Youngjae (Author) / Corley, Elizabeth A (Thesis advisor) / Darnall, Nicole (Committee member) / Guston, David (Committee member) / Arizona State University (Publisher)
Created2017
Description
This study aimed to advance understanding of the relation between social media and adolescent alcohol use while accounting for offline peer alcohol use, exploring offline peer alcohol use separately as a covariate and as a moderator, with an additional exploratory analysis of the relation between social media and alcohol use without offline peer alcohol use in the model. A total of 868 students (55% female) in grade 7 (n = 468) and grade 8 (n = 400) at wave 1, self-reported on alcohol use, binge drinking, and social media use as well as nominated friends from their school and grade. Data from nominated peers who also completed the questionnaires were used for peer-report of alcohol use. Data were collected annually from students at grades 8, 9, 10, and 11 were used in analyses. Final structural models consisted of a cross-lagged panel design with saved factor scores for social media and peer alcohol use predicting a categorical alcohol use variable or a binary binge drinking variable. With offline peer alcohol use as a covariate in the model, social media did not prospectively relate to subsequent grade alcohol use or binge drinking. However, without offline peer alcohol use, the path from social media use to subsequent grade alcohol use was significant but not the path to binge drinking. Offline peer alcohol use did not significantly moderate the relation between social media and subsequent grade alcohol use or binge drinking.
ContributorsCurlee, Alexandria Stephanie (Author) / Corbin, William R. (Thesis advisor) / Chassin, Laurie (Committee member) / Doane, Leah D (Committee member) / Grimm, Kevin J. (Committee member) / Arizona State University (Publisher)
Created2020
Description
Throughout western clarinet art music, there are not only a large number of great performers and classical works, but also a valuable body of literature that has laid a solid foundation for clarinet development and global dispersion. By contrast, Chinese clarinet literature is lacking in quantity and global distribution. However, this is the first comprehensive study that discloses the mysterious mask of China’s clarinet art.
This study does not merely discuss the Chinese clarinet history, but it also introduces important historical events that influenced the development of the Chinese clarinet industry (excluding manufacturing), including Chinese military bands, clarinet music, pedagogy, clarinet figures, and its future direction.
In the conclusion of this paper, the author discusses the deficiency of the Chinese clarinet industry and makes suggestions for solving problems with clarinet players practicing more technique rather than focusing on musicianship, educators’ lack of concentration on teaching and academic research, and the shortage of Chinese clarinet works. Additionally, the author appeals to Chinese clarinet players to actively participate in international activities and the Chinese government to increase incentives to introduce high-level Chinese talents overseas to help make China a better country in any field.
This study does not merely discuss the Chinese clarinet history, but it also introduces important historical events that influenced the development of the Chinese clarinet industry (excluding manufacturing), including Chinese military bands, clarinet music, pedagogy, clarinet figures, and its future direction.
In the conclusion of this paper, the author discusses the deficiency of the Chinese clarinet industry and makes suggestions for solving problems with clarinet players practicing more technique rather than focusing on musicianship, educators’ lack of concentration on teaching and academic research, and the shortage of Chinese clarinet works. Additionally, the author appeals to Chinese clarinet players to actively participate in international activities and the Chinese government to increase incentives to introduce high-level Chinese talents overseas to help make China a better country in any field.
ContributorsZhu, Shuang (Author) / Spring, Robert S (Thesis advisor) / Gardner, Joshua T (Thesis advisor) / Wells, Christopher (Committee member) / Micklich, Albie (Committee member) / Schuring, Martin (Committee member) / Arizona State University (Publisher)
Created2017
Description
Scaling of the Metal-Oxide-Semiconductor Field Effect Transistor (MOSFET) towards shorter channel lengths, has lead to an increasing importance of quantum effects on the device performance. Until now, a semi-classical model based on Monte Carlo method for instance, has been sufficient to address these issues in silicon, and arrive at a reasonably good fit to experimental mobility data. But as the semiconductor world moves towards 10nm technology, many of the basic assumptions in this method, namely the very fundamental Fermi’s golden rule come into question. The derivation of the Fermi’s golden rule assumes that the scattering is infrequent (therefore the long time limit) and the collision duration time is zero. This thesis overcomes some of the limitations of the above approach by successfully developing a quantum mechanical simulator that can model the low-field inversion layer mobility in silicon MOS capacitors and other inversion layers as well. It solves for the scattering induced collisional broadening of the states by accounting for the various scattering mechanisms present in silicon through the non-equilibrium based near-equilibrium Green’s Functions approach, which shall be referred to as near-equilibrium Green’s Function (nEGF) in this work. It adopts a two-loop approach, where the outer loop solves for the self-consistency between the potential and the subband sheet charge density by solving the Poisson and the Schrödinger equations self-consistently. The inner loop solves for the nEGF (renormalization of the spectrum and the broadening of the states), self-consistently using the self-consistent Born approximation, which is then used to compute the mobility using the Green-Kubo Formalism.
ContributorsJayaram Thulasingam, Gokula Kannan (Author) / Vasileska, Dragica (Thesis advisor) / Ferry, David (Committee member) / Goodnick, Stephen (Committee member) / Allee, David (Committee member) / Arizona State University (Publisher)
Created2017
Description
Extreme heat and its human impacts are significant public health challenges that disproportionately affect certain populations. Often, people with the least resources to cope with the heat also live in the hottest regions of cities. Previous heat vulnerability research has predominantly been conducted at a coarse geographic scale, yet translating relationships measured at aggregated scales to the individual level can result in ecological fallacy. Prior work has also primarily studied the most severe health outcomes: hospitalization/emergency care and mortality. It is likely that magnitudes more people are experiencing negative health impacts from heat that do not necessarily result in medical care. Such less severe impacts are under-researched in the literature.This dissertation addresses these knowledge gaps by identifying how social characteristics and physical measurements of heat at the individual and household level act independently and in concert to influence human heat-related outcomes, especially less severe outcomes. In the first paper, meta-analysis was used to quantify the summary effects of vulnerability indicators on incidence of heat-related illness. More proximal vulnerability indicators (e.g., residential air conditioning use, indoor heat exposure, etc.) tended to have the strongest impact on odds of experiencing heat-related illness than more distal indicators. In the next paper, indoor air temperature observations were related to the social characteristics of the residents. The strongest predictor of indoor air temperature was the residents’ ideal thermally comfortable temperature, despite affordability. In the final paper, fine scale biometeorological observations of the outdoor thermal environment near residents’ homes were linked to their experience with heat-related illness. The outdoor thermal environment appeared to have a stronger, more consistent impact on heat-related illness among households in a lower income neighborhood compared to a higher income one. These findings affirm the value of employing residential heat mitigation solutions at the individual and household scale, indoors and outdoors. Across all chapters, the indoor thermal environment, and the ability to modify it, had a clear impact on residents’ comfort and health. Solutions that target the most proximal causal factors of heat-related illness will likely have the greatest impact on reducing the burden of heat on human health and well-being.
ContributorsWright, Mary K (Author) / Hondula, David M (Thesis advisor) / Larson, Kelli L (Committee member) / Middel, Ariane (Committee member) / Arizona State University (Publisher)
Created2023
Description
ABSTRACT
"The Soul Unto Itself," a chamber music song cycle, was commissioned by the author, Rosa LoGiudice, and composed by William Clay, a doctoral candidate in composition at Arizona State University. The cycle was conceived and composed in the summer and fall of 2019. The chamber ensemble was a sextet comprised of Megan Law, mezzo-soprano, Kristi Hanno, clarinet, Emilio Vazquez, violin, Rittika Gambhir, bassoon, Nathaniel De la Cruz, double bass, and Rosa LoGiudice, piano, all based in Tempe, Arizona. The song cycle was premiered in a lecture recital on December 8, 2019 at Hammer and Strings Conservatory in Gilbert, AZ.
"The Soul Unto Itself" is a cycle of six songs based on poems of Emily Dickinson. The poems all have common themes of personal transformation achieved through the introspective observations of the poet. An unusual chamber ensemble was chosen to include instruments not commonly used in vocal chamber music in order to create a greater variety of musical colors and timbres. This project included the creation of the musical score, a live performance that was video recorded, and the research paper. This document discusses the process of working with the composer, rehearsing the music as it was being composed, and negotiating revisions necessary to make the music more effective in performance. Each song is discussed in detail, especially the connection between the music and poetry, the overall form of the song, revisions discussed and implemented, and important motivic relationships between the songs that unify the cycle. In summary, the process of collaborating with a composer is a rewarding experience for both the performers and the composer, as everyone is challenged to improve their craft and overcome obstacles to achieve a successful performance.
"The Soul Unto Itself," a chamber music song cycle, was commissioned by the author, Rosa LoGiudice, and composed by William Clay, a doctoral candidate in composition at Arizona State University. The cycle was conceived and composed in the summer and fall of 2019. The chamber ensemble was a sextet comprised of Megan Law, mezzo-soprano, Kristi Hanno, clarinet, Emilio Vazquez, violin, Rittika Gambhir, bassoon, Nathaniel De la Cruz, double bass, and Rosa LoGiudice, piano, all based in Tempe, Arizona. The song cycle was premiered in a lecture recital on December 8, 2019 at Hammer and Strings Conservatory in Gilbert, AZ.
"The Soul Unto Itself" is a cycle of six songs based on poems of Emily Dickinson. The poems all have common themes of personal transformation achieved through the introspective observations of the poet. An unusual chamber ensemble was chosen to include instruments not commonly used in vocal chamber music in order to create a greater variety of musical colors and timbres. This project included the creation of the musical score, a live performance that was video recorded, and the research paper. This document discusses the process of working with the composer, rehearsing the music as it was being composed, and negotiating revisions necessary to make the music more effective in performance. Each song is discussed in detail, especially the connection between the music and poetry, the overall form of the song, revisions discussed and implemented, and important motivic relationships between the songs that unify the cycle. In summary, the process of collaborating with a composer is a rewarding experience for both the performers and the composer, as everyone is challenged to improve their craft and overcome obstacles to achieve a successful performance.
ContributorsLoGiudice, Rosa Mia (Author) / Campbell, Andrew (Thesis advisor) / Ryan, Russell (Committee member) / Rockmaker, Jody (Committee member) / Arizona State University (Publisher)
Created2020
Description
China's city commercial banks were reorganized by the urban credit cooperatives in the same city in the 1990s. Although they are allowed to open branches outside the registered city, the location and the number of their branches have been strictly restricted. It is fatal to them to increase the competitiveness of their branches. Based on the diversity theory and its mechanism, in this study I examined the impact of source diversity of the senior management in the branches of the city commercial bank on the branches’ productivity and their asset yield. Invoking the resource-based theory and the social capital framework, the source diversity lead to the organization resources diversity and the organization knowledge diversity. The results demonstrate that the source diversity contribute to the branches’ competitiveness advantage. Both internal trained personnel and external introduction personnel are important for the branches’ top management team. But one of the two kinds of personnel is more suitable to their middle management team.
ContributorsZhang, Xiande (Author) / Gu, Bin (Thesis advisor) / Wang, Tan (Thesis advisor) / Shen, Wei (Committee member) / Arizona State University (Publisher)
Created2017
Description
Increasing globalization and the knowledge-based economy creates a higher-than-ever demand for skilled migrant labor. While Global North countries are the traditional destinations for skilled migrants, Global South countries have recently joined the race for such talent. The conventional migration scholarship does not adequately explain this increasing Global-North-to-South skilled migration. This dissertation fills the gap by studying mobility and its underlying factors for skilled U.S. migrants in the Pearl River Delta region of China. Using data from semi-structured interviews and sketch mapping, this dissertation develops a capital-mobility framework and employs intersectionality theory to examine the impacts of skilled U.S. migrants’ capital and intentionality on global and local spatial mobility as well as occupational and social mobility. The first empirical paper highlights skilled U.S. migrants’ cross-border im/mobility and introduces the capital-mobility framework that argues migrants’ im/mobility outcomes are shaped by their aspirations to move, and the accumulation, transferability and convertibility of various forms of capital. While the migrants’ capital was smoothly transferred to China and facilitated their voluntary mobility, the continued accumulation of capital in China could not be fully transferred to the U.S. upon their return, thus causing involuntary immobility. Although they mostly had little intention of staying in China permanently, the COVID-19 accelerated their return. The second empirical chapter shows that one’s accumulation of capital could generate both enabling and limiting effects on their everyday mobility through influencing the capability to move and the demand for local travel. Whether migrants had intention to move around in the local city also affects their everyday im/mobility. The third empirical paper discusses skilled U.S. migrants’ occupational and social mobility and how they are influenced by the intersections of race, gender and citizenship. I coined the term “glass box” to explain the limited professional growth and segregated occupations of skilled U.S. migrants’ occupational mobility in China. Although their social mobility improved after moving to China, it declined after rising racial discrimination and xenophobia during the pandemic. This dissertation sheds light on the aspirations and capabilities for mobility among Global-North-to-South skilled migrants and provides policy recommendations for attracting and retaining skilled international migrants.
ContributorsTan, Yining (Author) / Li, Wei (Thesis advisor) / Tsuda, Takeyuki (Committee member) / Tong, Daoqin (Committee member) / Nelson, Trisalyn (Committee member) / Arizona State University (Publisher)
Created2022
Description
Computational biophysics is a powerful tool for observing and understanding the microscopic machinery that underpins the biological world. Molecular modeling and simulations can help scientists understand a cell’s behavior and the mechanisms that drive it. Empirical evidence can provide information on the structure and organization of biomolecular machines, which serve as the backbone of biomolecular modeling. Experimental data from probing the cell’s inner workings can provide modelers with an initial structure from which they can hypothesize and independently verify function, complex formation, and response. Additionally, molecular data can be used to drive simulations toward less probable but equally interesting states. With the advent of machine learning, researchers now have an unprecedented opportunity to take advantage of the wealth of data collected in a biomolecular experiment. This dissertation presents a comprehensive review of atomistic modeling with cryo-electron microscopy and the development of new simulation strategies to maximize insights gained from experiments. The review covers the integration of cryo-EM and molecular dynamics, highlighting the evolution of their relationship and the recent history of MD innovations in cryo-EM modeling. It also covers the discoveries made possible by the integration of molecular modeling with cryo-EM. Next, this work presents a method for fitting small molecules into cryo-electron microscopy maps, which uses neural network potentials to parameterize a diverse set of ligands. The method obtained fitted structures commensurate with, if not better than, the structures submitted to the Protein Data Bank. Additionally, the work describes the data-guided Multi- Map methodology for ensemble refinement of molecular movies. The method shows that cryo-electron microscopy maps can be used to bias simulations along a specially constructed reaction coordinate and capture conformational transitions between known intermediates. The simulated pathways appear reversible with minimal hysteresis and require only low-resolution density information to guide the transition. Finally, the study analyzes the SARS-CoV-2 spike protein and the conformational heterogeneity of its receptor binding domain. The simulation was guided along an experimentally determined free energy landscape. The resulting motions from following a pathway of low-energy states show a degree of openness not observed in the static models. This sheds light on the mechanism by which the spike protein is utilized for host infection and provides a rational explanation for the effectiveness of certain therapeutics. This work contributes to the understanding of biomolecular modeling and the development of new strategies to provide valuable insights into the workings of cellular machinery.
ContributorsVant, John Wyatt (Author) / Singharoy, Abhishek (Thesis advisor) / Heyden, Matthias (Committee member) / Presse, Steve (Committee member) / Arizona State University (Publisher)
Created2024