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- Title
- Aerial photography
- Creator
- Schaeffer, Robert Owen
- Date
- 1938
- Collection
- Electronic Theses & Dissertations
- Title
- Pacific Standard Time : modernism and the making of West Coast jazz
- Creator
- Spencer, Michael Thomas
- Date
- 2011
- Collection
- Electronic Theses & Dissertations
- Description
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An interdisciplinary study of one of the most overlooked and understudied movements in the history of jazz, this dissertation draws from the fields of New Jazz Studies, Popular Culture Studies, and Art History in order to reconstruct the cultural history of West Coast jazz. Focusing on the critical texts and institutions that allowed this movement to germinate and expand, I explore the ways in which the music was represented through various types of media: on record, on radio, on screen, in...
Show moreAn interdisciplinary study of one of the most overlooked and understudied movements in the history of jazz, this dissertation draws from the fields of New Jazz Studies, Popular Culture Studies, and Art History in order to reconstruct the cultural history of West Coast jazz. Focusing on the critical texts and institutions that allowed this movement to germinate and expand, I explore the ways in which the music was represented through various types of media: on record, on radio, on screen, in concert, and in print (i.e., record labels, radio stations, jazz periodicals, etc.). As a result, this study recontextualizes the West Coast jazz movement within the milieu of California modernism around the middle 20th century as a way to observe the broader jazz community; one which included musicians as well as photographers, painters, architects, sculptors, filmmakers, and other modernists.
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- Title
- Matter and energy transformation : an investigation into secondary school students' arguments
- Creator
- Onyancha, Kennedy M.
- Date
- 2010
- Collection
- Electronic Theses & Dissertations
- Title
- Toward the development of a chemo-enzymatic process for the production of next-generation taxol analogs
- Creator
- Ondari, Mark Evans
- Date
- 2010
- Collection
- Electronic Theses & Dissertations
- Title
- Two thousand years of foraging ecology in the endangered Hawaiian petrel : insights from stable isotope analysis
- Creator
- Wiley, Anne E.
- Date
- 2011
- Collection
- Electronic Theses & Dissertations
- Description
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Recent evidence indicates that over the last 150 years, humans may have impacted seabird populations through modification of their marine food resources. Unfortunately, the high mobility and large pelagic ranges of many seabirds has resulted in a dearth of information concerning even their basic feeding habits. Here, I use stable isotope analysis to investigate the modern and ancient foraging ecology of an endangered seabird, the Hawaiian petrel (
Pterodroma sandwichensis )....
Show moreRecent evidence indicates that over the last 150 years, humans may have impacted seabird populations through modification of their marine food resources. Unfortunately, the high mobility and large pelagic ranges of many seabirds has resulted in a dearth of information concerning even their basic feeding habits. Here, I use stable isotope analysis to investigate the modern and ancient foraging ecology of an endangered seabird, the Hawaiian petrel (Pterodroma sandwichensis ). Stable isotopic composition of Hawaiian petrel tissues (δ13 C and δ15 N values) reflects trophic level and foraging location and can therefore be used to describe patterns of foraging segregation or long-term temporal variation within the species. Chapter 1 investigates isotopic variation within individual flight feathers, with the goal of designing minimally-invasive and ecologically informative sampling strategies. δ13 C values increased from tip to base in all 52 feathers within the study, including 42 remiges from the Hawaiian petrel and 10 from the Newell's Shearwater (Puffinus auricularis newelli ). Such a consistent trend, observable among different species and age classes, is unlikely to result from shifts in diet or foraging location during feather synthesis. Considerable variation of δ15 N values was also present within feathers (average range of 1.3 / within Hawaiian petrel remiges). A sampling protocol is proposed that requires only 1.0 mg of feather and minimal preparation time. Because it leaves the feather nearly intact, this protocol will likely facilitate obtaining isotope values from remiges of live birds and museum specimens. Chapter 2 explores ecological variability among modern Hawaiian petrel populations. δ13 C and δ15 N values of feathers demonstrate segregation in foraging location during both the breeding and non-breeding seasons for petrels nesting on Kauai and Hawaii. Genetic analyses based on the mitochondrial Cytochrome b gene also reveal strong differentiation: coalescent-based analyses estimate < 1 migration event per 1,000 generations. Finally, feathers from multiple age groups and islands show unexpected divergences in δD that cannot be related to variation in source water. Overall, these data demonstrate foraging and genetic divergence between proximately nesting seabird populations. This divergence occurs despite high species mobility and a lack of physical barriers between nesting sites.Chapter 3 investigates Hawaiian petrel foraging habits and inter-colony segregation over the course of approximately 2,000 years. The most pervasive temporal trend is a 1.4-2.6 / decrease in average δ15 N values, which likely reflects declining trophic level over the past 300-1,000 years. Isotopic chronologies also document ca. 2,000 years of foraging segregation between Hawaiian petrel colonies, observed as a long-standing divergence in average δ15 N values. The degree of foraging segregation between petrel colonies diminishes through time and correlates well with genetic population structure. Shifting foraging habits of the Hawaiian petrel may reflect relatively widespread trophic alterations in the pelagic realm of the North Pacific. Such changes in foraging are concerning, given their implications for reproductive success and genetic diversity.
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- Title
- Rater effects in ITA testing : ESL teachers' versus American undergraduates' judgments of accentedness, comprehensibility, and oral proficiency
- Creator
- Hsieh, Ching-Ni
- Date
- 2011
- Collection
- Electronic Theses & Dissertations
- Description
-
Second language (L2) oral performance assessment always involves raters' subjective judgments and is thus subject to rater variability. The variability due to rater characteristics has important consequential impacts on decision-making processes, particularly in high-stakes testing situations (Bachman, Lynch, & Mason, 1995; A. Brown, 1995; Engelhard & Myford, 2003; Lumley & McNamara, 1995; McNamara, 1996). The purposes of this dissertation study were twofold. First, I wanted to examine rater...
Show moreSecond language (L2) oral performance assessment always involves raters' subjective judgments and is thus subject to rater variability. The variability due to rater characteristics has important consequential impacts on decision-making processes, particularly in high-stakes testing situations (Bachman, Lynch, & Mason, 1995; A. Brown, 1995; Engelhard & Myford, 2003; Lumley & McNamara, 1995; McNamara, 1996). The purposes of this dissertation study were twofold. First, I wanted to examine rater severity effects across two groups of raters, English-as-a-Second-Language (ESL) teachers and American undergraduate students, when raters evaluated international teaching assistants' (ITAs) oral proficiency, accentedness, and comprehensibility. Second, I wanted to identify and compare rater orientations, that is, factors that drew raters' attention when judging the examinees' oral performances. I employed both quantitative and qualitative methodologies to address these issues concerning rater effects and rater orientations in the performance testing of ITAs at a large Midwestern university. Thirteen ESL teachers and 32 American undergraduate students participated in this study. They evaluated 28 potential ITAs' oral responses to the Speaking Proficiency English Assessment Kit (SPEAK). Raters evaluated the examinees' oral proficiency, accentedness, and comprehensibility, using three separate holistic rating scales. Raters also provided concurrent written comments regarding their rating criteria and participated in one-on-one interviews that explored raters' rating orientations. I employed a many-facet Rasch measurement analysis to examine and compare rater severity across rater groups using the computer program FACETS. I compared the written comments across groups to identify major rating criteria employed by the ESL teachers and the undergraduates. I analyzed the interview data to explore the reasons for rating discrepancies across groups. Results of the study suggested that the ESL teachers and the undergraduate raters did not differ in severity with respect to their ratings of oral proficiency. However, the comparisons of ratings in accentedness and comprehensibility were both statistically significant. The undergraduate raters were harsher than the teacher raters in their evaluations of examinees' accentedness and comprehensibility. Additionally, the analysis of the written comments identified six major rating criteria: linguistic resources, phonology, fluency, content, global assessment, and nonlinguistic factors. Cross-group comparisons of the rating criteria indicated that the undergraduate raters tended to evaluate the examinees' oral performances more globally than the ESL teachers did. In contrast, the ESL teachers tended to use a wider variety of rating criteria and commented more frequently on specific linguistic features. The interview protocols revealed that raters' experience with accented speech, perceptions of accent as an important rating criterion, and approaches to rating (i.e. analytical or global), had important bearings on raters' judgments of ITA speech.
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- Title
- Hydraulic evaluation of lysimeters versus actual evapotranspirative caps
- Creator
- Mijares, Ramil Garcia
- Date
- 2011
- Collection
- Electronic Theses & Dissertations
- Description
-
The ability to quantify percolation through a soil profile is one of the important considerations for geoenvironmental systems. Reliable estimates of percolation through natural soil deposits help in determining local groundwater recharge rates. For landfills, accurate measurement of percolation through the cap is necessary for permitting earthen final covers. Even though percolation is generally the smallest component among water balance parameters, quantifying its magnitude is...
Show moreThe ability to quantify percolation through a soil profile is one of the important considerations for geoenvironmental systems. Reliable estimates of percolation through natural soil deposits help in determining local groundwater recharge rates. For landfills, accurate measurement of percolation through the cap is necessary for permitting earthen final covers. Even though percolation is generally the smallest component among water balance parameters, quantifying its magnitude is environmentally critical and key in evaluating the overall hydraulic performance of final covers. Direct estimation of percolation through a soil cover is typically achieved using pan lysimeters which consist of a drainage layer underlain by an impermeable geomembrane liner. The presence of this hydraulic barrier in lysimeter, which is used to facilitate the collection and measurement of percolation, alters the hydraulics of the system. This dissertation aimed to evaluate the difference in hydraulic performance of a lysimeter versus actual earthen cap with underlying landfilled waste. Two uncompacted and one compacted field-scale earthen cap test sections were built and instrumented at a landfill near Detroit, Michigan to investigate the hydraulic difference between an actual cap (underlain by waste) and corresponding lysimeter which was used to directly measure percolation. Lysimeter pans were installed in the middle of each test sections and the instrumented area was expanded upslope and downslope of the lysimeter to monitor the soil water storages within and beyond the lysimeter footprint. About 35 sensors were installed in each of the test sections to monitor water contents, water potentials, soil temperatures, water levels, and gas pressures. The field results show soil water storage values for the uncompacted test sections that were underlain by waste were typically greater than those for the corresponding lysimeters. For the compacted test section, there was no significant difference between the soil water storage for the actual cap and the lysimeter. Using the single porosity numerical models UNSAT-H and Vadose/W, the field measured percolation in the lysimeter as well as the variation in soil water storages were predicted with an acceptable accuracy for the compacted test section. The presence of macropore flow through large clods in uncompacted test sections is not accounted for in these single porosity models. A numerical analysis showed that when a lysimeter underestimates the soil water storage of an actual earthen cap, it corresponds to greater actual percolation across the interface between the soil cover and the underlying waste. A lysimeter overestimates percolation because the infiltrated water drained into the lysimeter is immediately removed and is therefore not available for removal by evapotranspiration. Field-scale simulations also showed that the magnitude of capillary barrier effect introduced by the drainage layer in the lysimeters is negligible when the saturated hydraulic conductivity of the soil cover is equal to or less than 10^-5 cm/s.
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- Title
- Predicting differential item functioning in cross-lingual testing : the case of a high stakes test in the Kyrgyz Republic
- Creator
- Drummond, Todd W.
- Date
- 2011
- Collection
- Electronic Theses & Dissertations
- Description
-
Cross-lingual tests are assessment instruments created in one language and adapted for use with another language group. Practitioners and researchers use cross-lingual tests for various descriptive, analytical and selection purposes both in comparative studies across nations and within countries marked by linguistic diversity (Hambleton, 2005). Due to cultural, contextual, psychological and linguistic differences between diverse populations, adapting test items for use across groups is a...
Show moreCross-lingual tests are assessment instruments created in one language and adapted for use with another language group. Practitioners and researchers use cross-lingual tests for various descriptive, analytical and selection purposes both in comparative studies across nations and within countries marked by linguistic diversity (Hambleton, 2005). Due to cultural, contextual, psychological and linguistic differences between diverse populations, adapting test items for use across groups is a challenging endeavor. Of paramount importance in the test adaptation process is the proven ability of test developers to adapt test items across groups in meaningful ways. One way investigators seek to understand the level of item equivalence on a cross-lingual assessment is to analyze items for differential item functioning, or DIF. DIF is present when examinees from different language groups do not have the same probability of responding correctly to a given item, after controlling for examinee ability (Camilli & Shephard, 1994). In order to detect and minimize DIF, test developers employ both statistical methods and substantive (judgmental) reviews of cross-lingual items. In the Kyrgyz Republic, item developers rely on substantive review of items by bi-lingual professionals. In situations where statistical DIF detection methods are not typically utilized, the accuracy of such professionals in discerning differences in content, meaning and difficulty between items is especially important. In this study, the accuracy of bi-linguals' predictions about whether differences between Kyrgyz and Russian language test items would lead to DIF was evaluated. The items came from a cross-lingual university scholarship test in the Kyrgyz Republic. Evaluators' predictions were compared to a statistical test of "no difference" in response patterns by group using the logistic regression (LR) DIF detection method (Swaminathan & Rogers, 1990). A small number of test items were estimated to have "practical statistical DIF." There was a modest, positive correlation between evaluators' predictions and statistical DIF levels. However, with the exception of one item type, sentence completion, evaluators were unable to predict which language group was favored by differences on a consistent basis. Plausible explanations for this finding as well as ways to improve the accuracy of substantive review are offered. Data was also collected to determine the primary sources of DIF in order to inform the test development and adaptation process in the republic. Most of the causes of DIF were attributed to highly contextual (within item) sources of difference related to overt adaptation problems. However, inherent language differences were also noted: Syntax issues with the sentence completion items made the adaptation of this item type from Russian into Kyrgyz problematic. Statistical and substantive data indicated that the reading comprehension items were less problematic to adapt than analogy and sentence completion items. I analyze these findings and interpret their implications to key stakeholders, provide recommendations for how to improve the process of adapting items from Russian into Kyrgyz and highlight cautions to interpreting the data collected in this study.
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- Title
- Institutionalization of digital literacies in four-year Liberal Arts institutions
- Creator
- Wendt, Mary Ellen
- Date
- 2011
- Collection
- Electronic Theses & Dissertations
- Description
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Few in the field of Rhetoric and Writing debate digital literacy's value in higher level institutions today, yet while faculty in general echo this same value, the actual institutionalization of digital literacy--especially in liberal arts institutions--stands in question. This dissertation project, situated in the field of digital rhetoric and positioned theoretically with postmodern constructs, approaches research in digital literacy issues and "institutionalizing" digital literacy. I...
Show moreFew in the field of Rhetoric and Writing debate digital literacy's value in higher level institutions today, yet while faculty in general echo this same value, the actual institutionalization of digital literacy--especially in liberal arts institutions--stands in question. This dissertation project, situated in the field of digital rhetoric and positioned theoretically with postmodern constructs, approaches research in digital literacy issues and "institutionalizing" digital literacy. I examine findings using activity theory and genre theory to construct a model of the Operational Life Cycle of the Institutionalization of Digital Literacy. This model of the Operational Life Cycle has several purposes: it visually can enable others to navigate the murky journey of institutionalization; it provides a clear framework for understanding the complexities of institutional work; and it demonstrates the possibility that any size school, even with limited funds, can institutionalize digital literacy. This kind of model illuminates two ideas: One, the power of the centrifugal and centripetal outcomes (genres) of the activities in the Life Cycle, which can perpetuate and speed along such institutionalization. Two, such institutionalization requires the participation of the institution at large, English departments more specifically, and faculty members as individuals. Without such participation, holes in the Life Cycle render institutionalization of digital literacy much more difficult a challenge.
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- Title
- Anticipation of knowledge of success and problem-solving
- Creator
- Marr, John N.
- Date
- 1960
- Collection
- Electronic Theses & Dissertations
- Title
- Long-time convergence of harmonic map heat flows from surfaces into Riemannian manifolds
- Creator
- Choi, Kwangho
- Date
- 2011
- Collection
- Electronic Theses & Dissertations
- Description
-
We study the long-time convergence of harmonic map heat flows from a closed Riemann surface into a compact Riemannian manifold. P. Topping constructed an example of a flow that does not converge in the infinite-time limit. Motivated by the observation that Topping's flow has accumulation points at which the Hessian of the energy function is degenerate, we prove convergence under the assumptions that (a) the Hessian of the energy at an accumulation point is positive definite, and (b) no...
Show moreWe study the long-time convergence of harmonic map heat flows from a closed Riemann surface into a compact Riemannian manifold. P. Topping constructed an example of a flow that does not converge in the infinite-time limit. Motivated by the observation that Topping's flow has accumulation points at which the Hessian of the energy function is degenerate, we prove convergence under the assumptions that (a) the Hessian of the energy at an accumulation point is positive definite, and (b) no bubbling occurs at infinite time. In addition, we present examples of heat flows for geodesics which show that the convexity of the energy function and convergence at infinite time may not hold even for 1-dimensional harmonic map heat flows.
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- Title
- Relation between wind velocity and wind pressures
- Creator
- Branch, Robert M.
- Date
- 1931
- Collection
- Electronic Theses & Dissertations
- Title
- Efficiency studies at the Highland park pumping station
- Creator
- Rieger, William Norman
- Date
- 1941
- Collection
- Electronic Theses & Dissertations
- Title
- Identifying Palestinians : Palestinian refugees and the politics of ethno-national identity in Jordan
- Creator
- Pérez, Michael Vicente
- Date
- 2011
- Collection
- Electronic Theses & Dissertations
- Description
-
Based on extensive research (January 2006 - January 2008) among Palestinian refugees living within United Nations Relief and Works Agency camps in Amman, Jordan, my dissertation examines how the contingencies of local and transnational politics constitute particular forms of identification that underscore the possibilities and limits of Palestinian ethnicity and nationhood. My dissertation underscores three critical issues within the process of ethno-national identification among diaspora...
Show moreBased on extensive research (January 2006 - January 2008) among Palestinian refugees living within United Nations Relief and Works Agency camps in Amman, Jordan, my dissertation examines how the contingencies of local and transnational politics constitute particular forms of identification that underscore the possibilities and limits of Palestinian ethnicity and nationhood. My dissertation underscores three critical issues within the process of ethno-national identification among diaspora Palestinians. First, my research shows how Palestinian ethno-national identifications reflect two critical issues: (1) the exclusionary discourse and practices of Transjordanian nationalists and the Jordanian State and (2) the desire to identify as Palestinians, not Jordanians. To challenge their marginalization in Jordan, Palestinians rely on pan-Arab and religious identifications that emphasize their ethno-religious commonality with Jordanians while preserving their distinct ethno-national identification as Palestinians. Second, my research demonstrates how categories of national and religious identification among refugees indicate the intersections between local concerns and transnational politics. I show how the idioms of religious nationalism articulated by refugees concerning the homeland reflect the significance of Palestinian homeland politics in Jordanian camps and offer Palestinians an opportunity to assert national identifications in a context where Palestinian nationalism is strictly controlled. Finally, my dissertation examines how the unique experience and meaning of life as a refugee in Jordan facilitates national identifications defined in terms of displacement and exile. As I show, refugee status constitutes a central point of identification among Palestinians that enables specific forms of ethnic and national belonging grounded in the experience of prolonged displacement and the myth of return.This dissertation reflects a central concern over the impact of transnational migration and displacement upon the formation and meaning of ethno-national communities and their location within the nation-state. My work examines how ethnic and national categories, whether at the level of the state, national elites, or everyday people, are produced within the nexus of local and transnational struggles that underscore the often contentious position of migrant communities within host states and homeland politics. By recognizing that the process of identification among displaced peoples reflects transnational realities, my research highlights the instability of social categories and the conditions under which they are represented, resisted, and claimed.
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- Title
- Statistical and computational methods for biological data
- Creator
- Hao, Yuning
- Date
- 2019
- Collection
- Electronic Theses & Dissertations
- Description
-
The development of biological data focuses on machine learning and statistical methods. In immunotherapy, gene-expression deconvolution is used to quantify different types of cells in a mixed population. It provides a highly promising solution to rapidly characterize the tumor-infiltrating immune landscape and identify cold cancers. However, a major challenge is that gene-expression data are frequently contaminated by many outliers that decrease the estimation accuracy. Thus, it is imperative...
Show moreThe development of biological data focuses on machine learning and statistical methods. In immunotherapy, gene-expression deconvolution is used to quantify different types of cells in a mixed population. It provides a highly promising solution to rapidly characterize the tumor-infiltrating immune landscape and identify cold cancers. However, a major challenge is that gene-expression data are frequently contaminated by many outliers that decrease the estimation accuracy. Thus, it is imperative to develop a robust deconvolution method that automatically decontaminates data by reliably detecting and removing outliers. Our development of an algorithm called adaptive Least Trimmed Square (aLTS) identifies outliers in regression models, allows us to effectively detect and omit the outliers, and provides us robust estimations of the coefficients. For the guarantees of the convergence property and parameters recovery, we also included certain theoretical results.Another interesting topic is the investigation of the association of phenotype responses with the identified intricate patterns in transcription factor binding sites for DNA sequences. To address these concerns, we pushed forward with a deep learning-based framework. On one hand, to capture regulatory motifs, we utilized convolution and pooling layers. On the other hand, to understand the long-term dependencies among motifs, we used position embedding and multi-head self-attention layers. We pursued the improvement of our model's overall efficacy through the integration of transfer learning and multi-task learning. To ascertain confirmed and novel transcription factor binding motifs (TFBMs), along with their relationships internally, we provided interpretations of our DNA quantification model.
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- Title
- Role of propionate and uncouplers of oxidative phosphorylation on hepatic metabolism and feeding behavior in dairy cows
- Creator
- Kennedy, Katherine Marie
- Date
- 2019
- Collection
- Electronic Theses & Dissertations
- Description
-
The negative energy balance of dairy cows in the postpartum period is exacerbated by a suppression in appetite. Metabolic diseases resulting from negative energy balance can decrease milk production, health and fertility, increasing risk of culling. Research suggests that feeding behavior is linked to the oxidation of fuels in the liver and that an increase in oxidation of fuels causes satiety. Propionate derived from the fermentation of starch in the rumen is a major glucose precursor in...
Show moreThe negative energy balance of dairy cows in the postpartum period is exacerbated by a suppression in appetite. Metabolic diseases resulting from negative energy balance can decrease milk production, health and fertility, increasing risk of culling. Research suggests that feeding behavior is linked to the oxidation of fuels in the liver and that an increase in oxidation of fuels causes satiety. Propionate derived from the fermentation of starch in the rumen is a major glucose precursor in dairy cows but can also cause hypophagia. Because propionate is anaplerotic, it stimulates the oxidation of fuels in the liver, likely causing the hypophagic effects. In order to determine the role of anaplerotic metabolites and uncouplers of oxidative phosphorylation on hepatic metabolism and feeding behavior in dairy cows, 6 studies were conducted. First, using 8 dairy cows in a duplicated 4x4 Latin square design, the effect of feed status (before or after access to feed) on the hepatic extraction and metabolism of propionate over 20 min was determined. The results indicated that hepatic extraction and metabolism of propionate is very rapid, and that metabolite concentrations were greater after compared with before feeding. Additionally, potential bottlenecks of propionate metabolism were identified. Secondly, a study using hepatic explants incubated in [13C3]sodium propionate was conducted to test the effects of 3 different concentrations of propionate (1, 2 or 4 mM) on propionate metabolism over 60 min. An increased concentration of propionate in the range from 1 - 4 mM resulted in the conversion of propionate to acetyl CoA, likely through pyruvate, and that the acetyl CoA was incorporated into the TCA cycle for oxidation. Additionally, metabolism of [13C3]propionate occurred rapidly with significant increases of 13C enrichment detected within 0.5 min for many metabolites. Furthermore, uncoupling the electron transport chain should affect the metabolism of propionate and the feeding behavior of dairy cows as a result of inefficient oxidation of fuels. The effects of two uncouplers of oxidative phosphorylation, 2,4-dinitrophenol methyl ether (DNPME) and sodium salicylate (SAL), on feeding behavior in dairy cows were determined in 2 experiments. Treatment with DNPME and SAL decreased eating rate in dairy cows over the first 4 h following access to feed. Additionally, DNPME increased meal length over the first 4 h following access to feed. Lastly, an experiment was conducted to determine the effects of DNPME and SAL on metabolism and oxidation of propionate over 60 min using hepatic explants from 8 dairy cows. Neither DNPME nor SAL increased oxidation. The DNPME treatment did not alter metabolism of propionate except for an increase of propionate converted to succinyl CoA, however, SAL decreased glucose synthesis from propionate. From this research, we conclude that hepatic metabolism of propionate occurs rapidly and is likely having effects on feeding behavior within minutes as well. As such, the importance of short-term metabolism in regard to feeding behavior and dry matter intake should be considered in future research. Understanding the mechanisms for metabolic control of feed intake will lead to development of novel nutritional or pharmacological approaches to increase energy intake, health, and milk yield of dairy cows; thus, improving nutrient utilization and sustainability of the dairy industry.
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- Title
- Tailoring the growth and electronic structure of organic molecular heterointerfaces
- Creator
- Tan, Andrew W. J.
- Date
- 2019
- Collection
- Electronic Theses & Dissertations
- Description
-
In the rapidly developing electronics industry, it has become increasingly necessary to explore materials that are cheap, flexible and versatile which have led to significant research efforts towards organic molecular thin films. Understanding and control of heterointerface between highly ordered organic molecular thin films with extended π systems and inorganic materials are therefore of critical importance for the development of modern organic electronics. Organic molecules are unique...
Show moreIn the rapidly developing electronics industry, it has become increasingly necessary to explore materials that are cheap, flexible and versatile which have led to significant research efforts towards organic molecular thin films. Understanding and control of heterointerface between highly ordered organic molecular thin films with extended π systems and inorganic materials are therefore of critical importance for the development of modern organic electronics. Organic molecules are unique compared to their inorganic atomic counterparts as their properties can be tuned drastically through chemical functionalization, offering versatility, though their extended shape and weak intermolecular interactions bring significant challenges to the control of both the growth and the electronic structures of molecular thin films. This is further complicated by interaction between organic molecules and the underlying substrate which can lead to interfacial effects such as charge transfer, chemical interaction and electrostatic screening, all of which can significantly impact device performance and/or the characteristic of the organic thin film. This dissertation will first focus on a systematic review of the growth and electronic structure of organic molecular thin films, particularly on weakly interacting substrates. The self-assembly process and how long-range ordered organic molecular thin films are established will be discussed. We will also discuss how the electronic structures of thin films are impacted by the molecule’s local electrostatic environment and its interaction with the substrate, within the context of controlling interfacial energy level alignment between organic semiconductors and electrodes in electronic devices. Employing scanning tunneling microscopy and spectroscopy, experimental studies focusing on characterizing the growth and electronic structure of organic molecules on weakly interacting substrates were carried out and discussed. Studies focusing on the electronic structure of zinc phthalocyanine (ZnPc) and its fluorinated counterpart F16ZnPc were carried out on the deactivated Si(111)-B surface and h-BN/Cu(111). We show that interfacial charge transfer occurs between the deactivated Si(111)-B substrate and the F16ZnPc monolayer, which gives rise to a pronounced spatial variation of the occupied molecular state across the molecular assembly attributed to the inhomogeneous electrostatic screening of the intra-orbital Coulomb interaction in molecular adsorbates arising from the substrate boron distribution in the deactivated Si(111)-B substrate. To circumvent this inhomogeneous effect, the donor-acceptor molecular pair was studied on weakly interacting hexagonal boron nitride (h-BN)/Cu(111) which possesses a periodic electronic corrugation. We show that the formation of the lateral heterostructure drastically increases the charge transfer between F16ZnPc molecules and the substrate, which is attributed to the greater electrostatic stability of the heterostructure compared to that of the pure phase. This study highlights the importance of the substrate, even a weakly interacting one, such as h-BN/metal, can still perturb the intermolecular charge transfer and thereby the heterostructure behaviors via interfacial processes. The focus of a secondary study was to initiate preliminary experimentation towards understanding the substrate’s influence on the exotic properties of a class of organic-based systems known as charge transfer complexes (CTC). By utilizing the unique modulation properties of various weakly-interacting substrates, control of the properties of CTCs could be attained allowing for a better understanding of their fundamental physical mechanism to be developed and a new class of thin-film CTCs which will be highly relevant towards organic electronics to be developed.
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- Title
- Testing a model of healthy marriage/healthy relationships : the prediction of parenting and child well-being
- Creator
- Shambleau, Krista M.
- Date
- 2010
- Collection
- Electronic Theses & Dissertations
- Description
-
Federally funded Healthy Marriage Initiative (HMI) programs provide marriage education as well as other services to low-income diverse individuals and couples at many points along the marital continuum with improving children's well-being as the overarching purpose. These programs need appropriate measures of healthy marriage for couples with children that relate to well-being. Purposes of this research were to examine the factor structure of a healthy marriage measurement developed by...
Show moreFederally funded Healthy Marriage Initiative (HMI) programs provide marriage education as well as other services to low-income diverse individuals and couples at many points along the marital continuum with improving children's well-being as the overarching purpose. These programs need appropriate measures of healthy marriage for couples with children that relate to well-being. Purposes of this research were to examine the factor structure of a healthy marriage measurement developed by Manpower Demonstration Research Corporation (MDRC) and how it varied across (a) gender, (b) race (African American and Caucasian), and (c) marital status (married and unmarried). An additional purpose was to test a measurement model, developed by Child Trends, Inc., in which healthy marriage is hypothesized to predict parenting and child well-being. This cross-sectional quantitative survey research included 343 Head Start parents (151 males and 189 females) involved in a marriage/relationship. Overall, the unidimensional healthy marriage measurement fit for both males and females and the addition of two marital virtues, namely forgiveness and teamwork, also loaded well on this measurement. The factor loadings were significant for both males and females and results of chi-square difference tests indicated that the factor loadings for the great majority of variables were invariant across gender. However, the factor loading for relationship stability (one's assessment that their relationship is not in trouble) was larger for males whereas child commitment (one's assessment of their spouse/partner's commitment to their child) was larger for females. Path analysis demonstrated that the Child Trends, Inc. healthy marriage measurement model fit differed by gender and this was supported by further SEM analysis. The effect size for the direct path between risk and healthy marriage was significantly larger for females than for males. The effect size of this path tended to be greater for African American women and unmarried women. Results using fit indices showed that the fit of the measurement model was appropriate for the diverse sample. Mediation results revealed that for both males and females, healthy marriage partially mediates the effect that depression and stress have on parenting. For females, parenting partially mediates the effect between risk and children's social competence as well as between healthy marriage/healthy relationships and children's social competence. Findings demonstrate support for the Child Trends' measurement model that healthy marriage/healthy relationships may enhance children's social competence through positive parenting. Study results may inform federal and state healthy marriage and family initiatives as well as marriage and relationship education in terms of program delivery and evaluation.
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- Title
- The regiments : cultural histories of Zulu masculinities and gender formation in South Africa, 1816-2018
- Creator
- Timbs, Elizabeth H.
- Date
- 2019
- Collection
- Electronic Theses & Dissertations
- Description
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"This dissertation reconstructs aspects of the history of Zulu martial heritage through the prism of the amabutho (regiments, age-grades) in KwaZulu-Natal, South Africa, from the era of Shaka Zulu (ca. 1816) to the present. Based on archival research and oral history interviews, this study argues that despite being outlawed by the British colonial regime in 1879, Zulu chiefs continued to form amabutho, but for different purposes. Regiments became youth structures for commercial labor...
Show more"This dissertation reconstructs aspects of the history of Zulu martial heritage through the prism of the amabutho (regiments, age-grades) in KwaZulu-Natal, South Africa, from the era of Shaka Zulu (ca. 1816) to the present. Based on archival research and oral history interviews, this study argues that despite being outlawed by the British colonial regime in 1879, Zulu chiefs continued to form amabutho, but for different purposes. Regiments became youth structures for commercial labor recruitment and British military conscription; they enabled indigenous leaders to access martial discourse and metaphors for political mobilization; expressed cultural forms of resistance to state racism; and nurtured the sustenance of Zulu identities in a changing South Africa. Exploring the amabutho's links to the Zulu monarchy also helps to shed light on the evolving role and status of the Zulu Royal House. While both the white-run Natal and Union governments feared the influence that Shaka's successors held among Zulu-speaking Africans, the authorities also relied on Paramount Chief Solomon to recruit black volunteers from Natal and Zululand for World War I. In the apartheid era (1948-1994), the invocation of the Zulu nation's warrior legacy endured. As migrant laborers, Zulu men recreated their martial identities and manifestations of the amabutho became more abstract, emerging in society, culture, and politics in unexpected ways. As the struggle against apartheid intensified, the continued relevance of this martial heritage mobilized Zulu communities, bringing them in conflict with first the African National Congress and later the United Democratic Front. In the post-apartheid period (1994-present), the rhetoric, symbolism, and practices of Zulu regiments continues to resonate and evolve. In the case of "high politics," Zulu political leaders turn to martial metaphors to engender support, while, on the ground, local authorities throughout the province struggle to maintain the traditions that give these metaphors meaning. The historiographical significance of this dissertation is threefold. First, it extends earlier studies to consider Zulu martial masculinity over two centuries. Second, it uncovers how amabutho shaped, and have been shaped by, white anxieties about Zulu men's "violent potential" as well as a need for cheap labor. Third, this dissertation reconsiders the shifting role of chiefs and kings in South Africa since 1800."--Pages ii-iii.
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- Title
- Essays in the economics of education
- Creator
- Lee, Hwanoong
- Date
- 2019
- Collection
- Electronic Theses & Dissertations
- Description
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"This dissertation comprises three essays on the Economics of Education. Its ultimate focus is to understand how different agents in the education market respond to releasing information about teacher and school performance and how public interventions influence human capital accumulation. The first essay "The Effect of Releasing Teacher Performance Information to Schools: Teachers' Response and Student Achievement" examines the effects of releasing teacher value-added (VA) information on...
Show more"This dissertation comprises three essays on the Economics of Education. Its ultimate focus is to understand how different agents in the education market respond to releasing information about teacher and school performance and how public interventions influence human capital accumulation. The first essay "The Effect of Releasing Teacher Performance Information to Schools: Teachers' Response and Student Achievement" examines the effects of releasing teacher value-added (VA) information on student performance in two settings; in the first, VA data was released to all potential employers within the district, while in the second, only the current employer received the data. I find that student achievement increased only in the district where the VA scores were provided to all potential employers. These effects were driven solely by improved performance among ex-ante less-effective teachers; the null effects in the other setting, however, were driven by moderate declines in performance among ex-ante highly-effective teachers and small improvements among less-effective teachers. These results highlight the importance of understanding how the design features of VA disclosure translate into the productivity of teachers. The second essay "The Role of Credible Threats and School Competition within School Accountability Systems: Evidence from Focus Schools in Michigan" studies the impact of receiving accountability labels on the student achievement distribution under No Child Left Behind (NCLB) waivers. Using a sharp regression discontinuity (RD) design, I examine the achievement effects of Focus (schools with the largest achievement gaps) labels and find that schools receiving the Focus label improved the performance of low-achieving students relative to their barely non-Focus counterparts, and they did so without hurting high-achieving students. The positive achievement effects for Focus schools were entirely driven by Title 1 Focus schools that faced financial sanctions associated with being labeled the following year. There is no evidence of an achievement effect associated with the Priority label. Next, I examine heterogeneous effects by looking at the number of alternative nearby schooling options. I find that when schools are exposed to a competitive choice environment, receiving the Focus label increased math test scores across the scoring distribution, while schools located in an uncompetitive choice environment improved the test scores of low achievers only. This evidence may suggest the importance of incorporating credible sanctions and school choice options into the school accountability system to maximize the effectiveness of the system on student achievement. Finally, the third essay "The Effects of School Accountability Systems Under NCLB Waiver: Evidence from Priority Schools in Michigan" investigates the impact of receiving Priority labels on the student achievement distribution under No Child Left Behind (NCLB) waivers. Using a sharp regression discontinuity (RD) design, I examine the achievement effects of the Priority (schools with the lowest performance) label and find no evidence of an achievement effect associated with the Priority label. Next, I examine whether assigning the Priority label induced the changes in the composition of students. I define several key measures of student composition and find no evidence that the Priority designation influenced the student composition of schools."--Pages ii-iii.
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