Doctoral Dissertations (Winter 2014 to Present)
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New submissions to the University of Delaware Doctoral Dissertations collection are added as they are released by the Office of Graduate & Professional Education. The Office of Graduate & Professional Education deposits all dissertations from a given semester after the official graduation date.
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Item First-principles-based kinetic modeling of the zeolite-catalyzed conversion of furans to aromatics(University of Delaware, 2014) Nikbin, NimaThe development of strategies to convert renewable feedstocks into fuels and chemicals and displace petroleum is motivated from economic, environmental and political reasons and is arguably one of the world's foremost scientific energy challenges. The nascent shale gas revolution may, at best, postpone the transition to renewables. Shale gas, however, does not provide aromatics to the extent that naphtha does and thus the development of renewables-based strategies for aromatics is more crucial than ever. A promising, sustainable route to synthesize aromatics from biomass-derived furans has recently been proposed following the discovery that DMF and ethylene can be selectively converted to p-xylene by dehydration of the Diels-Alder product over zeolites that contain Brønsted sites. The objective of this thesis is to reveal the underlying mechanism and provide insights into catalyst design principles. In order to achieve this, we combine electronic structure calculations and microkinetic modeling to describe how the two reactions - Diels-Alder cycloaddition and dehydration - work in tandem and to investigate the side reactions that affect selectivity. Specifically, we study the Brønsted acid-catalyzed dehydration of the cycloadduct and the ring opening hydrolysis reaction of DMF. We show that Brønsted acids are quite effective at catalyzing dehydration and hydrolysis. We pay particular attention to the ability of zeolites with extra-framework Lewis acid centers to heterogeneously catalyze the Diels-Alder cycloaddition. We elucidate the factors that determine Lewis acid activity and propose reactivity descriptors that encapsulate the underlying physics. In order to accomplish this study, we vary the active Lewis acid site environment from an isolated active site center to an active site cluster model and an embedded active site cluster model to determine the balance between accuracy and computational cost and guide future computational studies about a suitable way of modeling the active site. Even though Lewis acids are known to catalyze Diels-Alder cycloaddition by closing the gap between the frontier molecular orbitals of the addends, our calculations show that alkali-exchanged zeolites Y do not generally exhibit notable Lewis acid activity. Charge screening of the Lewis acid centers, due to significant charge transfer from the framework oxygen atoms to the alkali cations, diminishes their catalytic ability. As a result, the reaction is shown to follow bi-directional instead of normal electron flow and homogeneous catalyzed chemistry is equally effective. We propose that effective heterogeneous catalysis of Diels-Alder cycloaddition should involve zeolite frameworks whereby the Lewis acid centers are less embedded and thus less screened from electron density transfer from the framework. Microkinetic modeling of the conversion of DMF and ethylene over the zeolite HY revealed that HY can only catalyze the dehydration of the Diels-Alder product and that the cycloaddition itself proceeds uncatalyzed, outside the zeolite, i.e., homogeneously. The overall process follows two distinct kinetic regimes as a function of catalyst concentration. At low catalyst loadings, the rate of p-xylene production increases linearly with the concentration of active sites and the rate-limiting step is the Brønsted-catalyzed dehydration. At high catalyst loadings, the reaction rate is maximal and independent of the available Brønsted sites. In this regime, the rate is controlled by the uncatalyzed cycloaddition, despite the fact that the cycloaddition activation energy is higher than that of the catalyzed dehydration.Item Sparse signal processing for machine learning and computer vision(University of Delaware, 2014) Zhou, YinSignal sparse representation solves inverse problems to find succinct expressions of data samples as a linear combination of a few atoms in the dictionary or codebook. This model has proven effective in image restoration, denoising, inpainting, compression, pattern classification and automatic unsupervised feature learning. Many classical sparse coding algorithms have exorbitant computational complexity in solving the sparse solution, which hinders their applicability in real-world large-scale machine learning and computer vision problems. In this dissertation, we will first present a family of locality-constrained dictionary learning algorithms, which can be seen as a special case of sparse coding. Compared to classical sparse coding, locality-constrained coding has closed-form solution and is much more computationally efficient. In addition, the locality-preserving property enables the newly proposed algorithms to better exploit the geometric structures of data manifold. Experimental results demonstrate that our algorithms are capable of achieving superior classification performance with substantially higher efficiency, compared to sparse-coding based dictionary algorithms. Sparse coding is an effective building block of learning visual features. A good feature representation is critical for machine learning algorithms to achieve satisfactory results. In recent years, unsupervised feature learning has received increasing research interest in various computer vision and pattern recognition problems. Unlike humanengineered feature extractors that typically require domain knowledge and a large amount of labeled data, unsupervised learning algorithms are generic and designed to automatically discover the intrinsic patterns from the abundant unlabeled data that are usually readily available (from Internet) and require no laborious human labeling. In this dissertation, we will explore the capability of feature learning algorithms in automated biomedical image analysis. Specifically, we will present two unsupervised feature learning models for histopathology image classification. We will also introduce a novel convolutional regression model for nuclei segmentation. Experiments on biomedical image classification and segmentation benchmarks demonstrate that the proposed feature learning systems can achieve very competitive results compared to dedicated systems incorporating biological prior knowledge. Finally, we propose a sparse coding based framework for classifying complicated human gestures represented as multi-variate time series (MTS). Specifically, we will present a novel feature extraction strategy, which can overcome the problem of inconsistent lengths among MTS data and is robust to the large variability within human gestures. Moreover, we will introduce a generic approach to kernelize sparse representation, which leads to enhanced classification performance. Extensive experiments verify the effectiveness of the proposed framework.Item Exploring natural supersymmetry at the LHC(University of Delaware, 2014) Nasir, FarihaThis dissertation demonstrates how a variety of supersymmetric grand unified theories can resolve the little hierarchy problem in the minimal supersymmetric standard model and also explain the observed deviation in the anomalous magnetic moment of the muon. The origin of the little hierarchy problem lies in the sensitive manner in which the Z boson mass depends on parameters that can be much larger than its mass. Large values of these parameters imply that a large fine tuning is required to obtain the correct Z boson mass. With large fine tuning supersymmetry appears unnatural which is why models that attempt to resolve this problem are referred to as natural SUSY models. We show that a possible way to exhibit natural supersymmetry is to assume non-universal gauginos in a class of supersymmetric grand unified models. We further show that considering non-universal gauginos in a class of supersymmetric models can help explain the apparent anomaly in the magnetic moment of the muon.Item Dioxygen activation by low valent cobalt complexes supported by ferrocenyl-substituted, redox active hydrotris(pyrazolyl)borate ligands(University of Delaware, 2014) Sirianni, Eric R.The successful synthesis and structural characterization of a new family of second and third generation ferrocenyl-substituted tris(pyrazolyl)borate ligands was achieved. These ligands employ ferrocenyl (Fc) moieties for increased C-H bond strengths as well as maintaining the steric demands necessary to remain "tetrahedral enforcers". The thallium(I) salts of the TP Fc* (1 ) and TpFc,Me* (2 ) ligands were isolated as N-confused asymmetric isomers. However, Tp Fc,iPr Tl (3 ) was isolated as the symmetric ligand as a dimer with an apparent Tl - Tl interaction. Cyclic voltammetry of 1, 2 , and 3 revealed single, reversible, three electron redox processes which suggests a lack of electronic communication between the ferrocenyl moieties when bound to a hydrotris(pyrazolyl)borate ligand. Conversely, TpCF3,Fc Tl (4 ) displays an irreversible redox process that is accompanied by decomposition during the oxidation wave of the CV. Thallium salts 1 and 2 undergo borotropic rearrangements to form the symmetric TpFc Tl (7 ) and Tp Fc,Me Tl (8 ), respectively. These ligands react with CoX 2 (X: Cl, I) to form their symmetric TpCoX complexes. Salt metathesis of 3 with CoI2 led to the isolation of TpFc,iPr CoI (13 ) as the only observable product. However, the reaction of 3 with CoCl2 yielded an N-confused Tp Fc,iPr* CoCl (14 ) complex. The electronic characterization of TpFc, (R: H, Me, i -Pr) has been sought through the synthesis of their corresponding copper(I) carbonyl complexes. Although the reaction of 7 and 8 with CuI under CO yields the symmetric TpFc Cu(CO) (16 ) and Tp Fc,Me Cu(CO) (17 ), respectively, the reaction of 3 with CuI under CO yielded the singly N-confused TpFc,iPr* Cu(CO) (19 ) and doubly N-confused TpFc,iPr** Cu(CO) (18 ) complexes. The TpFc,Me ligand has been employed in cobalt oxygen chemistry and has displayed its ability to resist C-H bond activation on the ligand. TpFc,Me Co(η3 -C3 H 5 ) (22 ) reacted with O2 to form an apparent TpFc,Me CoOOC3 H5 intermediate which underwent O - O bond homolysis to form TpFc,Me CoOH (21 ). 22 reacted with CO to form TpFc,Me Co(CO) (23 ). 23 reacts with O2 to form the side-on superoxo complex, TpFc,Me Co(O2 ), which has been structurally characterized by X-ray diffraction. Furthermore, the terminal imido complex, TpFc,Me CoNAd (25 ), displayed greater thermal stability than its analogous alkyl-substituted TptBu,Me CoNR complexes.Item Essays on computational applications in land and environmental economics(University of Delaware, 2014) Fooks, Jacob R.This dissertation presents three papers. The first considers a new approach to measuring and estimating willingness-to-pay for the class of nonmarket amenities with spatially explicit components. The second examines the significance, and a possible solution for poorly observed benefits in a conservation planning setting. The third reports on experiments in mechanisms for funding the development of coastal infrastructure, a spatially explicit public good, given complex inundation dynamics.Item The effects of high-speed, low-force recumbent cycling: an intervention in older a dults [sic] and Parkinson's disease(University of Delaware, 2014) Bellumori, MariaDecreased mobility substantially reduces independence and quality of life while contributing to increased rates of disability and health care costs. Exercise is a proven strategy to improve these qualities. Exercise is known to benefit every physiological system with the strongest literature support for cardiovascular health and strength gains. However, less is known about the potential to enhance mobility with exercises that target rapidly adapting central nervous system (CNS) factors. While the current exercise recommendations from federal agencies (CDC, NIH, and DHHS) are prudent, they neglect the potential benefits of high speed exercises that target the CNS correlates of muscular quickness. Results of this research are expected to inform improvements in exercise recommendations for older adults and people with movement disorders. Additionally, results are expected to fill a gap in the literature related to neural adaptations to high speed training in older adults and people with Parkinson's disease (PD). The purpose of Aim 1 was to determine whether there exist age-related differences in the speed and control of rapid isometric force pulses in different muscles in young and older adults. It was hypothesized that older adults would have lesser rate of force development-scaling factors (RFD-SF) and more variability in the performance of rapid force production. The purpose of Aim 2 was to determine the effects of a six week exercise intervention that uses high-speed, low-resistance stationary recumbent cycling in older adults. Participants completed pre- and post-exercise tests as well as 4 week follow-up to determine retention of changes. It was hypothesized that there would be improvements in the following measures: 1) Time to peak force and the RFD-SF during isometric knee extension; 2) Standardized measures of walking function; 3) Perceived function and quality of life. It was also hypothesized that improvements in the previous measures would be retained four weeks after training. To elucidate the neuromuscular mechanisms that occur with improved speed in older adults, it was hypothesized that this would be most strongly related to the rate of rise in the surface electromyogram (RER). We also aimed to determine if training the legs affects CNS mechanisms that transfer to the following in older adults: 1) Increased time to peak force and RFD-SF during isometric elbow extension; 2) Improved RER in elbow extensors; 3) Improved hand dexterity. It was also hypothesized that improvements in the previous measures would be retained four weeks after training. The purpose of Aim 3 was to develop an improved method to selectively quantify paired motor unit discharge behavior underlying tremor. The method was then tested before and after three different treatments. It was hypothesized that interspike interval serial correlation with cluster analysis would allow us to quantify paired motor unit discharge behavior from isometric contractions in which motor unit discharge behavior is not solely bimodal.Item Towards an equitable cap-and-trade scheme in South Korea: based on input-output analysis of the distributional implications of carbon pricing mechanisms(University of Delaware, 2014) Kim, HanaWhile the efficiency of cap-and-trade programs has attracted the attention of several countries, equity implications of the programs require equal attention. The programs impact income distribution as the cost of mitigation is passed on to consumers in the form of increased prices. A great deal of literature shows that the incidence of these programs is regressive in developed countries, indicating that this program will exacerbate the distributional equity without appropriate countermeasures. Facing the impending implementation of cap-and trade schemes in South Korea in 2015, a handful of experts have studied the equity implications of the scheme. The literature often provides a partial analysis on equity implications of the scheme focusing only on regional distribution or on distribution between different income groups. However, this dissertation evaluates the comprehensive equity implications of a carbon pricing policy as well as the impacts on other dimensions. Input-output analysis (IOA) is employed to assess the comprehensive impacts of a carbon pricing policy in South Korea. Beyond a typical IOA, hybrid IO tables are developed to estimate energy consumption and CO 2 emissions by sector and to analyze the impacts of the implementation on different sectors. In addition, this study makes it possible to assess equity implications by introducing a transition matrix to link Household Survey Data with the IO table. The analysis of three different carbon-pricing scenarios reveals that a comprehensive participation scenario (S1) impacts economy less adversely than the partial participation case (S2). The S1 more adversely impacts the distribution without revenue recycling. Coal consumption is reduced more in the S2 and the reduction in non-energy use such as naphtha is larger in the S1. Of course, a higher carbon price (S3) can reduce more emissions and energy consumption, but can more adversely affect economy and distributional equity. Regardless of scenarios, the analysis shows that the households with lower capacity, such as those with low-income or with elderly heads, are likely to be more adversely affected. However, these groups can be beneficiaries if the program is in practice together with revenue recycling through lump-sum transfer. In addition, there is not great difference between the burdens on rural and urban households. In conclusion, there is no best-case scenario for every dimension. Since the policy impacts economy, energy, environment and equity--important pillars of sustainable development--we need to consider the comprehensive impacts of the policy. In addition, we need to explore a more effective method to recycle the revenue to alleviate the inequity.Item Examining the physiology of harmful microalgae during algicidal control and diel vertical migration(University of Delaware, 2014) Tilney, Charles L.The frequency of harmful algal blooms (HABs) has increased, and so too has the societal and environmental costs associated with them. Anthropogenic eutrophication has played some part in this, but is not always implicated, as HABs and their drivers are diverse. Continued investigation into HAB biology and ecology may help to identify the underlying factors controlling algal blooms in general, and factors implicated in their recent increase in particular. Investigation of the various methods for the prevention, control, and mitigation of HABs is also warranted, to identify 'solutions' to reduce or eliminate some or all of the costs imposed by HABs. In this dissertation, both basic and applied work was conducted, initially on the control of dinoflagellates with a sterile bacterially-derived algicidal filtrate that is strongly specific toward dinoflagellates, and then on the diel vertical migration (DVM) of two potentially harmful species of microalgae. Initial investigations of the algicidal filtrate (termed IRI-160AA) assessed the effects in cultured dinoflagellates, and identified that electron transport through the photosynthetic apparatus at photosystem II (PSII) was broadly inhibited in algicide treated dinoflagellates. Moreover, IRI-160AA induced dose-dependent effects on both cell viability and PSII efficiency, and although dinoflagellate responses were highly species specific, one apparent generalization was that thecae reduced overall susceptibility. Next, the algicidal filtrate was tested on field collected water samples containing dinoflagellates. These dinoflagellates were less susceptible than uni-algal cultures because they were not in the most susceptible phase of growth, which corroborated the idea of Pokrzywinski et al. (2012) that identifying the growth stage of dinoflagellate blooms in the field would be crucial to achieving high levels of bioactivity with the algicide. Using a combination of polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE) and quantitative real-time PCR, I determined what changes occurred in the eukaryotic and prokaryotic microbial communities after applications of IRI-160AA. A common theme among these applications was the rise of bactivorous protists, most notably Paraphysomonas spp., which likely arose as a response to bacterial growth from dissolved organic matter (DOM) within the filtrate and released from dying dinoflagellates. This result highlighted how the microbial loop might transfer dinoflagellate carbon back to higher trophic levels in large-scale applications, and perhaps in HAB control more generally. The results suggest that IRI-160AA could be a potent and species-specific method to control harmful dinoflagellates in nature, but future work is required to identify methods to appropriately and cost-effectively scale- up algicide production, as well as to isolate the active compounds and determine the molecular targets and mode of action. Finally, a detailed comparison of the diel vertical migrations (DVM) of two sympatric harmful algal species (Karlodinium veneficum and Chattonella subsalsa ) was conducted in laboratory columns under various sampling regimes and lighting conditions. Both species exhibited markedly different DVM patterns, which were consistent with different photoprotective mechanisms, and carbon assimilation rates. DVM was found to be under the control of a circadian clock in C. subsalsa but not K. veneficum. This work provides a useful comparison between two potentially harmful species from the Delaware Inland Bays, and improves our understanding of the niches that these algae are adapted to. Collectively, this dissertation has raised many interesting questions for future research addressing the control of harmful algae with biologically derived compounds, and laid important foundations for deeper investigations into the role of diel vertical migration in two cosmopolitan harmful algae.Item Energy transfer in nanostructured materials(University of Delaware, 2014) Haughn, ChelseaEnergy transport and loss are critical to the performance of optoelectronic devices such as photovoltaics and terahertz imaging devices. Nanostructured materials provide many opportunities to tailor transport and loss parameters for specific device applications. However, it has been very difficult to correlate specific nanoscale structural parameters with changes in these performance metrics. I report the development of new ways of using time-resolved photoluminescence (TRPL) to probe charge and energy transport and loss dynamics. These techniques are applied to several types of nanostructured materials, including bulk semiconductors with defects, self-assembled quantum dots and colloidal quantum dots. First, GaAs/InP double heterostructures grown via metal organic chemical vapor deposition (MOCVD) were characterized with TRPL. TRPL is typically used to extract minority carrier lifetimes, but we discovered that the measured lifetime depended critically on the intensity of the exciting laser. We developed a Shockley-Read-Hall model to extract trap state densities from intensity-dependent TRPL measurements. Second, we characterized energy and charge transfer between InAs quantum dots and ErAs nanoinclusions within III-V heterostructures. Using intensity- and temperature-dependent TRPL, we confirmed tunneling as the dominant mechanism of charge transport and characterized the electronic structure of the ErAs nanoparticles. Finally, we characterized energy transport in colloidal quantum dot cascade structures. These cascade structures utilize Forster Resonance Energy Transfer and trap state recycling to funnel excitons from donor layers to acceptor layers and suggest a promising method for avoiding losses associated with surface trap states. Collectively, the analysis of these disparate material types advances our understanding of energy dynamics in nanostructured materials and improves our ability to design the next generation of photovoltaic and optoelectronic materials and devices.Item Modulation of paracrine interactions between prostate cancer cells and bone marrow stromal cells by transforming growth factor-beta signaling during colonization of bone(University of Delaware, 2014) Kurtoglu, SenemProstate cancer (PCa) is the most prevalent cancer and the second leading cause of cancer related death for men in the United States. Death is primarily due to bone metastasis with more than 80% of men who die of PCa having bone involvement at autopsy. The complex bone microenvironment may initially resist the newly resident PCa cells but PCa cells acquire adaptive changes that allow them to survive and grow in the "hostile" new microenvironment as they co-evolve in their genotypic and phenotypic characters with bone cells. We have previously shown that soluble factors released from immortalized human bone marrow stromal cells (BMSC) induce apoptosis of PCa cells, and the surviving cells undergo neuroendocrine differentiation (NED), characterized by morphological changes consistent with a neuroendocrine phenotype. The presence of neuroendocrine tumor cells in PCa is associated with aggressiveness, resistance to hormonal therapy, and poor prognosis. Using the LNCaP progression model of increasingly metastatic and castrate-resistant prostate cancer (CRPC) cell lines, I examined the influence of BMSC factors on PCa survival, using the HS-5 and HS-27a BMSC lines, which were characterized previously for their ability to support different stages of hematopoiesis. Neuroendocrine markers were elevated in PCa cells surviving HS-5 BMSC conditioned medium (CM) treatment, while differentiation markers such as androgen receptor (AR) and prostate-specific antigen (PSA) were decreased. PCa cells that undergo NED using HS-5 BMSC CM or serum withdrawal had elevated phosphorylated-Smad2 levels. Furthermore, NED of PCa cells prevented HS-5 BMSC-induced apoptosis. Cell death induced by BMSC CM was analyzed using live/dead analysis while the effect on cell growth was examined in soft agarose colony formation assays in the presence and absence of intact TGF-Beta signaling. Using immunoblotting and luciferase reporter assays, I measured levels and activity of phosphorylated-Smad2 in PCa cells surviving treatment with HS-5 BMSC CM. Treatment of PCa cells with the ALK-4, 5, and 7 kinase inhibitor, SB-431542, resulted in a significant reduction in HS-5-mediated cell death. Correspondingly, pre-treatment of HS-5 BMSC with TGF-Beta1 yielded a CM that elicited a marked reduction in PCa cell death. The ancillary TGF-Beta receptor endoglin levels were also decreased upon TGF-Beta1 stimulation of HS-5 cells suggesting the importance of endoglin in mediating BMSC-induced PCa cell death. Small interfering RNA-mediated knockdown of endoglin in HS-5 cells verified that the effect on PCa cell death was a direct result of the attenuation of endoglin. Futhermore, the loss of the cytoplasmic domain of endoglin in HS-5 cells attenuated BMSC-induced PCa cell death indicating the importance of the cytoplasmic domain in maintaining endoglin function and expression of the factor(s) responsible for PCa cell death. Collectively, my findings indicate that 1) TGF-Beta signaling in PCa cells is induced during stimulation of NED, 2) TGF-Beta family cytokines secreted from HS-5 BMSC mediate PCa cell death, 3) TGF-Beta signaling in HS-5 BMSC alters paracrine signaling to promote PCa survival, 4) Endoglin is required for HS-5 BMSC-induced PCa cell death, 5) The cytoplasmic domain of endoglin is required for the expression of the factor(s) responsible for PCa cell death.Item Thermochemical conversion of biomass: models and modeling approaches(University of Delaware, 2014) Moreno, Brian MatthewFuels produced from lignocellulosic biomass are a promising renewable energy source that will aid in the transition from petroleum-derived liquid transportation fuels while utilizing the existing processing and distribution infrastructures. Lignocellulosic biomass is composed of lignin, cellulose, and hemicellulose, in fractions that vary by plant species. Pyrolysis of these biopolymers results in a biomass pyrolysis oil (BPO) containing aromatics, hydrocarbons, and various oxygenated species. The high oxygen content of BPO must be decreased before use in conventional internal combustion engines. Deoxygenation of BPO results in a mixture of hydrocarbons with properties similar to those of petroleum-derived fuels, which can be co-processed in traditional refineries. The compositional variability of both the petroleum and biomass fractions motivates the need for molecular-level kinetic models to track these novel species and reaction pathways during the production of biofuel-petroleum blends. Molecular-level modeling of the thermochemical conversion of biomass requires the prediction of reaction networks that identify each chemical pathway from the biomass feedstock to the desired fuel products. The Klein research group has developed a software package that is capable of rapidly generating complete reaction networks and associated kinetic models. First, the Interactive Network Generator (INGen) produces a reaction network from the molecular reactants. Next, the Kinetic Modeling Editor (KME) automatically writes the corresponding rate equations and material balances for each species. The resulting molecular-level kinetic model is solved numerically to provide model predictions of the product composition at varying process conditions. In this dissertation, the capabilities of these software tools are expanded to incorporate various biomass chemistries. The biomass-to-fuels models described in this dissertation provide insight into competing kinetic pathways for the production of renewable liquid fuels from lignocellulosic materials. Predictions are made for product composition at varying feedstock composition and processing conditions; experimental data provides validation. Comparison of the activation energy barriers for competing deoxygenation routes will direct catalyst research to modulate between pathways and provide the highest quality products at the mildest process conditions. The ability to rapidly generate and solve molecular-level kinetic models will enable real-time optimization of fuel production and increase the viability of biofuels in the renewable energy market.Item From the ground up: conceptualizing the space of Los Angeles commercial aeromobility(University of Delaware, 2014) Edlins, GeoffreyDespite the capacity of air travel to radically transform life on the ground, aerial space is seldom considered a site whose constitutive practices, technologies, and physical forces have indeed reconfigured social, political, economic, and spatial relations--both within and between terrestrial city-regions. This dissertation integrates aeromobility and atmospheric space within a relational mode of urban analysis. It analyzes the processually-unfolding atmospheres of Los Angeles city-regional air passenger traffic. To do this, it first considers the spatial development of the Los Angeles city-regional airport system as a functional assemblage within nested, overlapping, and aerial-enabled relationships among city-regional infrastructures and institutions. It traces the production of urban forms and processes most directly related with the commercial airline activity centered on LAX and neighboring airports, which relationally configure the Los Angeles city-region, both within and throughout global air traffic networks. This analysis finds, among other things, that LAX has undergone a shift towards transpacific linkages. Future growth in these markets suggests the airport must accommodate larger aircraft and more intensive passenger flows. The project then describes how one protracted struggle over the reuse by Orange County of a decommissioned military air base can help us understand more fully that aerial spatial production is informed not only by political or economic interests, including demands for more a more even distribution of intensifying LAX air traffic throughout LA city-regional facilities, either operational or dormant. The project finds that, despite these regional demands, aerial spatial production becomes constrained and enabled to certain degrees by the materiality of air and air travel, including the topographical context of existing airport sites, the configuration and condition of runways, prevailing wind or weather patterns, the presence of aerial flows involving nearby airports, and the physical laws governing flight itself. Within this discussion, the dissertation considers some of the major institutional practices and arrangements that have assembled the Los Angeles city-regional airport system as a site of intersection between networked infrastructures and a territorial palimpsest. The analysis suggests that forms of political resistance to airport expansion and construction--which often appeal to improving how airport neighbors dwell-on-the-earth --can become strengthened by integrating appeals to improving how passengers and pilots dwell-in-the-air. The research contributes to an understanding of urban space and governance, particularly of how aerial-related institutions and actors constitute the city both as territorially-bounded node and relationally-articulated network.Item Particles and particle-verb constructions in English and other Germanic languages(University of Delaware, 2014) Larsen, DarrellThis dissertation examines the lexical semantics of particles and the syntax of particles and particle-verb constructions. I argue against the notion that there are distinct types of particles (e.g. resultative versus idiomatic versus aspectual), claiming instead that they are semantic predicates consisting of an often metaphorical spatial meaning and, with a few exceptions, an unpronounced Ground argument. As a result, particle verbs are argued to be semantically compositional. The syntactic behavior of particle verbs is primarily explained through the adoption of the following major claims: (i) particles are optionally projecting syntactic heads whose topmost projection merges with a verbal head to form either a complex head or a resultative-like structure; (ii) nonprojecting particles (which combine with verbs to form complex heads) remain in situ, the verb raising out of the complex via phonological head movement; and (iii) objects raise to receive Case by LF, but they may do so overtly or covertly. These claims are shown to account for the behavior of the particle-verb construction when interacting with a wide range of other phenomena. The adoption of a further claim--(iv) ECM subjects of small-clauses preferably or obligatorily (depending on the speaker) raise out of the small clause overtly, whereas ECM subjects of IPs need not--is then shown to be able to explain the pattern of grammaticality and acceptability judgments encountered in the so-called 'complex' particle-verb constructions. Finally, the ability of particle verbs to undergo various word-formation processes is considered within the context of these theoretical assumptions.Item Transition metal catalysis of acetals and pivalates: enantioselective and enantiospecific methods for C-C & C-B bond formation(University of Delaware, 2014) Harathi Dwarakanath, SrinivasThis dissertation focuses on the development of transition metal-catalyzed reactions of acetal and pivalate substrates. These new methods enable efficient synthesis of highly enantioenriched organic molecules. The first chapter discusses an enantioselective alkynylation of chromene acetals using copper (I) catalysts. In this method, we have observed wide substrate scope, and high enantioselectivities were observed especially with 4-aryl chromene acetals. Use of dilute conditions, BF 3 OEt2 as Lewis acid and Cy2 NMe as base are critical for achieving high enantioselectivities. In this chapter, a mechanism and stereochemical model are proposed that rationalize the observed substituent effects and enantioselectivities. This method demonstrates the advantage of using transition metal catalysis to facilitate reactions involving oxocarbenium ion intermediates. Chapter 2 discusses enantiospecific, nickel-catalyzed cross-couplings of benzylic pivalates with mild and functional group tolerant arylboroxines as cross-coupling partners. The diarylalkane and triarylmethane products formed were obtained in high yields and levels of stereochemical fidelity. The success of this method depends on the use of Ni(cod) 2 as catalyst and NaOMe as base. In this method, we have shown broad substrate scope and wide functional group tolerance. Chapter 3 discusses an enantiospecific, nickel-catalyzed cross-coupling of 1,3-disubstituted secondary allylic pivalates with mild and functional group tolerant arylboroxines. The 1,3-diaryl allyl products are obtained with high levels of stereochemical fidelity and yields. Excellent regioselectivity and E/Z selectivity are also observed in this method. A wide variety of functional groups are tolerated, and the utility of this method is demonstrated in the synthesis of the anti-inflammatory drug (S )-ketoprofen. Chapter 4 discusses an enantiospecific, nickel-catalyzed cross-coupling of 1,3-disubstituted secondary allylic pivalates and bis(pinacolato)diboron (B2 Pin2 ) to form γ-aryl allyl boronates in high yields and ee's. In this method, the absolute configuration of the allylboronate product depends on the ligand and the solvent used. Thus, either enantiomer of allyl boronate is available from the same enantiomer of pivalate starting material. The optimized conditions for obtaining both retention and inversion products are discussed.Item Novel preclinical targets and therapies for treatment of osteoarthritis(University of Delaware, 2014) Srinivasan, Padma PradeepaOsteoarthritis (OA) is the principal cause of disability in the aging population, yet there are no successful pharmacological interventions which can reverse or prevent the degeneration of articular cartilage. Evidently, thorough understanding of the disease pathology at the cellular level is mandatory to develop disease-modifying drugs for OA. This dissertation is aimed at understanding the role of various biochemical factors involved in the pathogenesis of OA and targeting them to develop novel interventions. Towards achieving this goal, my first approach show that the controlled release of a heparan sulfate binding growth factor, Bone Morphogenetic Protein 2 (BMP2), using perlecan-modified biomaterials can induce anabolic changes in cartilage of mice with early OA. As the growth factor therapy becomes ineffective in the later stages of OA and since the clinical manifestation and diagnosis of OA mostly occurs late when the patients develop pain, my next approach was to target the subchondral bone changes in early OA. Recent work showed that mechanotransduction in bone is partially mediated through voltage-sensitive calcium channel (VSCC) and mice deficient in Cav3.2, the pore forming subunit of T-VSCC have reduced response to mechanical loading and decreased bone remodeling properties. I used this Cav3.2 T-VSCC knockout (KO) mouse to demonstrate that reduced mechanosensitivity in subchondral bone is beneficial in preventing load-induced OA. I demonstrate that mechanotransduction from osteoblasts via T-VSCC induces local metabolite secretion that stimulates osteoarthritic changes in chondrocytes and propose that targeting calcium channels in joints would slow/prevent progression of OA. Next, I identify leptin as one of the subchondral bone-derived catabolic factors expressed by the mechanically stimulated osteoblasts and I explore the therapeutic potential of inhibiting osteoblast-derived leptin activity in a post-traumatic mouse model of OA. Through this dissertation work I demonstrate novel potential targets and therapeutics that can be used at early and later stages of OA. With the rapid climb in the life expectancy and the associated increase in OA prevalence, clinical application of these strategies can help improve the quality of life in OA patients and reduce the heath care expenditure associated with knee replacement surgeries.Item Implementation of a comprehensive literacy program at Gauger-Cobbs Middle School(University of Delaware, 2014) Shaw, HaroldThis Executive Position Paper documents efforts taken to establish a comprehensive school-wide literacy program at Gauger-Cobbs Middle School. Consistent with secondary schools across the nation, school-wide and sub-group achievement data for Gauger students supported the need for an increased focus in the area of literacy. Efforts taken were aligned to the research-based "elements of effective secondary literacy programs", identified by Biancaros and Snow (2006) in their report entitled Reading next--A vision for action and research in middle and high school literacy. These efforts included implementation of new literacy strategies, professional development activities, program evaluation, review of research based interventions and reflection activities to support Response to Intervention, the development of the master schedule, and to support increased self-efficacy. In addition to describing each effort, the paper reports the findings and reflections associated with each action taken. As a final element, the paper examines missed opportunities and positive takeaways, before identifying recommendations for future actions.Item Overhead, uncertainty, and interference in wireless networks(University of Delaware, 2014) Feng, HaoIn general, the performance of many wireless systems is approaching the fundamental limits on transmission capacity. For example, current commercial wireless standards such as 3GPP LTE-A and IEEE 802.11ac have a near-optimal physical layer. In order to meet the ever growing demand for capacity, other directions for improving network performance must be found. In most existing research on wireless networks, overhead, the "non-data'' portion including coordination, control signaling and other costs of serving different purposes, is assumed to be negligible. However, the final application throughput could be much lower than the theoretical bounds as a result of overhead, especially in large and dynamic networks. Therefore, it is critical to quantitatively analyze the overhead in wireless networks, which could provide clear insights on the performance in practical systems and could help to identify opportunities for improvements in their designs. Surprisingly, the fundamental limits on overhead are largely unknown, and the framework needed to design overhead-aware systems has not been adequately investigated. In addition, interference is one of the main performance-limiting factors in most future wireless applications. Conventional "interference avoidance'' techniques might not be feasible because the degrees of freedom (for example, bandwidth, number of orthogonal codes, and time) might be limited. Although the interference can be mitigated quite efficiently with centralized control, existing approaches are usually very sensitive to channel uncertainties; if the knowledge of the channel state information is imperfect, the system performance could be severely degraded. Also, collecting accurate information incurs a significant amount of overhead due to the time-varying nature of the wireless medium. Thus, it is imperative to jointly consider overhead, uncertainty, and interference. In this dissertation, we investigate practical and overhead-aware designs that can achieve better performance in a realistic networking context. We start with a simple, single-user, two-hop cooperative relaying network model. For this model, we first prove that M -group cooperation is the optimal distributed space-time block coding strategy when neither central control nor inter-relay communications is permitted. Then, we consider the relay selection problem where a small and acceptable amount of overhead is allowed. The tradeoff between the feedback overhead and the performance is investigated via rate distortion theory. Compared to existing research, which is usually highly dependent on the specific implementation approaches, the analysis presented here addresses the fundamental tradeoff of a general network. Using our theoretical results, we also compare practical centralized and decentralized relay selection schemes in terms of spectral efficiency. Then, interference-limited networks with multiple concurrent transmissions are studied. We analyze and compare the performance of cooperative and non-cooperative schemes. Although cooperation among relay nodes increases the reliability of point-to-point transmission, it also produces a higher level of interference and degrades the overall performance of a multi-user network. The tradeoff between cooperative gain and the additional interference is investigated, and a criterion which determines whether we should cooperative or not is derived. We next focus on multi-hop linear networks, which have one or more intermediate nodes along the path that receive and forward information via wireless links. Instead of assuming equal hop distances, we propose a novel model that permits randomness in the node locations, and then we determine the optimum number of hops for maximizing the end-to-end spectral efficiency. Then, for a multi-hop linear network with cooperative relays, a relay deployment strategy is proposed and studied. After that, for downlink multi-user networks, we present a novel quantization technique, sparse coding quantization (SCQ), which is an extension of classic vector quantization (VQ) and provides a balance between performance and complexity. In particular, the computational complexity of conventional VQ can be significantly reduced by applying SCQ, with a negligible reduction in performance. Comparisons among different quantization techniques are also provided. Beside considering specific quantization schemes, we also study the overhead-performance tradeoff for general MU-MIMO systems by applying a rate distortion framework. Finally, we investigate robust a user pairing problem for a heterogeneous network in the presence of channel uncertainty. Different definitions of robustness and uncertainty are considered to formulate the corresponding optimization problems. We develop an algorithm that is robust to uncertainty in channel measurement and thereby performs well in practical systems. Simulation results validate the robustness of the proposed method.Item The Arctic energy budget, sea ice area, and the atmospheric circulation(University of Delaware, 2014) Chan, WeihanArctic amplification and changes in Arctic sea ice has led to questions regarding the role of the Arctic in mid-latitude climate. All studies concerning the factors and the impacts suggest that changes in the Arctic system occur in association with altered energy fluxes. Therefore, this study explores Arctic energy fluxes in detail concentrating on their temporal and regional characteristics using the Climate Forecast System Reanalysis (CFSR) dataset. To understand how energy flux variations affect the Arctic climate, interactions among energy flux variables, Arctic sea ice, and prominent atmospheric teleconnections are investigated. These interactions are analyzed from two spatial perspectives: the entire Arctic and the sub-Arctic regions. Results from the entire Arctic showed that the annual cycle and the spatial distribution of energy fluxes follow the seasonal cycle, latitudinal variation, and surface conditions. No significant long-term trends are found for the energy flux variables; however, the accumulated total energy tendency suggests a prolonged period with energy flux surplus from 1995-2006. Significant correlations were found among energy fluxes, sea ice, and the NAO suggesting that sea ice variations are connected with changes in atmospheric circulation through the surface energy flux (F sfc ) directly or indirectly through the atmospheric energy transport (TEDIV). Maps of the spatial correlations show stronger relationships between these variables in unique regions. Hence, studying these energy fluxes and the relationship from a regional perspective is essential. Examination of coherent regions shows that the annual cycle and the time series of the Arctic sub-regions are similar to the average for the entire Arctic following the solar cycle and without long-term linear trends. Only the annual cycle for TEDIV show differences among regions and do not resemble the average Arctic pattern. Additionally, a hypothetical pathway with two time-scales of variation is suggested. These two levels of influence complement each other and provide a comprehensive picture of the interactions among Arctic energy fluxes, sea ice, and atmospheric circulation. Further, the analysis suggests that sea ice variation is an important factor in modulating Arctic energy fluxes, and the Kara region plays a critical role in linking sea ice variability and atmospheric circulation.Item Assessing results of years one, two, and three implementation of response to intervention(University of Delaware, 2014) Conaway, ElizabethThis study describes Morris Early Childhood Center's efforts to implement RtI as effectively as possible to help all its students learn to read. It describes and eveluates the staff's efforts to achieve this goal by improving scheduling to maximize instructional time, by strengthening professional development opportunities, and by more effectively individualizing reading instruction through differentiated grouping.Item A nation that is religious: Indonesia, the Ahmadiyah, and the state's SARA echoes(University of Delaware, 2014) Bottomley, Daniel C.This study explores the Indonesian state's role in the constitution, renegotiation, and regulation of Islamic and Indonesian identities through the Ahmadiyah controversy. The Ahmadis (a small sect whose beliefs regarding the Islamic Prophethood diverge from mainstream Islam) provide a lens through which state actions and non-elite reactions can be critically engaged and understood in Indonesia's broader context and history. What it reveals is an Indonesian governing apparatus that continues to rely on SARA logics of discipline and control used under the authoritarian rule of Suharto despite Indonesia's post-authoritarian transformations in government and governing. Through three cases of these SARA echoes of the past, snapshots of Indonesian nationalism emerge as the state's evolving role in regulating Muslim identities in Indonesia and prosaic responses to the state can be better understood. Ultimately, the Ahmadi dilemma provides a partial glimpse into Indonesia's ongoing national evolution and the means through which the nation is reproduced and disciplined.