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Physical Sciences and Mathematics Commons™

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2018

University of Louisville

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Articles 1 - 30 of 48

Full-Text Articles in Physical Sciences and Mathematics

Studying Galaxy Troughs And Ridges Using Weak Gravitational Lensing With The Kilo-Degree Survey, Margot M. Brouwer, Vasiliy Demchenko, Joachim Harnois-Déraps, Maciej Bilicki, Catherine Heymans, Henk Hoekstra, Konrad Kuijken, Mehmet Alpaslan, Sarah Brough, Yan Chuan Cai, Marcus V. Costa-Duarte, Andrej Dvornik, Thomas Erben, Hendrik Hildebrandt, Benne W. Holwerda, Peter Schneider, Cristóbal Sifón, Edo Van Uitert Dec 2018

Studying Galaxy Troughs And Ridges Using Weak Gravitational Lensing With The Kilo-Degree Survey, Margot M. Brouwer, Vasiliy Demchenko, Joachim Harnois-Déraps, Maciej Bilicki, Catherine Heymans, Henk Hoekstra, Konrad Kuijken, Mehmet Alpaslan, Sarah Brough, Yan Chuan Cai, Marcus V. Costa-Duarte, Andrej Dvornik, Thomas Erben, Hendrik Hildebrandt, Benne W. Holwerda, Peter Schneider, Cristóbal Sifón, Edo Van Uitert

Faculty Scholarship

We study projected underdensities in the cosmic galaxy density field known as 'troughs', and their overdense counterparts, which we call 'ridges'. We identify these regions using a bright sample of foreground galaxies from the photometric Kilo-Degree Survey (KiDS), specifically selected to mimic the spectroscopic Galaxy And Mass Assembly survey. Using background galaxies from KiDS, we measure the weak gravitational lensing profiles of the troughs/ridges. We quantify the amplitude of their lensing strength A as a function of galaxy density percentile rank P and galaxy overdensity δ, and find that the skewness in the galaxy density distribution is reflected in the …

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Substellar And Low-Mass Dwarf Identification With Near-Infrared Imaging Space Observatories, Benne W. Holwerda, J. S. Bridge, R. Ryan, M. A. Kenworthy, N. Pirzkal, M. Andersen, S. Wilkins, R. Smit, S. R. Bernard, T. Meshkat, R. Steele, R. C. Bouwens Dec 2018

Substellar And Low-Mass Dwarf Identification With Near-Infrared Imaging Space Observatories, Benne W. Holwerda, J. S. Bridge, R. Ryan, M. A. Kenworthy, N. Pirzkal, M. Andersen, S. Wilkins, R. Smit, S. R. Bernard, T. Meshkat, R. Steele, R. C. Bouwens

Faculty Scholarship

Aims. We aim to evaluate the near-infrared colors of brown dwarfs as observed with four major infrared imaging space observatories: the Hubble Space Telescope (HST), the James Webb Space Telescope (JWST), the Euclid mission, and the WFIRST telescope. Methods. We used the SPLAT SPEX/ISPEX spectroscopic library to map out the colors of the M-, L-, and T-type dwarfs. We have identified which color-color combination is optimal for identifying broad type and which single color is optimal to then identify the subtype (e.g., T0-9). We evaluated each observatory separately as well as the narrow-field (HST and JWST) and wide-field (Euclid and …

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Innate Immunity, The Hepatic Extracellular Matrix, And Liver Injury: Mathematical Modeling Of Metastatic Potential And Tumor Development In Alcoholic Liver Disease., Shanice V. Hudson Dec 2018

Innate Immunity, The Hepatic Extracellular Matrix, And Liver Injury: Mathematical Modeling Of Metastatic Potential And Tumor Development In Alcoholic Liver Disease., Shanice V. Hudson

Electronic Theses and Dissertations

The overarching goals of the current work are to fill key gaps in the current understanding of alcohol consumption and the risk of metastasis to the liver. Considering the evidence this research group has compiled confirming that the hepatic matrisome responds dynamically to injury, an altered extracellular matrix (ECM) profile appears to be a key feature of pre-fibrotic inflammatory injury in the liver. This group has demonstrated that the hepatic ECM responds dynamically to alcohol exposure, in particular, sensitizing the liver to LPS-induced inflammatory damage. Although the study of alcohol in its role as a contributing factor to oncogenesis and …

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Framing Climate Change As National Security: A Survey-Experiment On Climate Change Perceptions., Adam Lyons Dec 2018

Framing Climate Change As National Security: A Survey-Experiment On Climate Change Perceptions., Adam Lyons

Electronic Theses and Dissertations

The issues surrounding climate change continue to have polarizing effects on many Americans. In this thesis I offer a potential bridge to this divide with a comprehensive study on how issue frames can impact how individuals shape their opinions on environmental issues. Focusing on a national security frame, I ask the central research “Will the public perceive issues of climate change differently when they are framed as threats to national security?” For this thesis I design an original experimental survey to measure the impact security framing has on participants’ perception of both climate change and environmental policy options. The survey …

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Computational Prediction, Characterization, And Methodology Development For Two-Dimensional Nanostructures: Phosphorene And Phosphide Binary Compounds., Congyan Zhang Dec 2018

Computational Prediction, Characterization, And Methodology Development For Two-Dimensional Nanostructures: Phosphorene And Phosphide Binary Compounds., Congyan Zhang

Electronic Theses and Dissertations

In this thesis, a comprehensive computational simulation was carried out for predicting, characterizing, and applications of two-dimensional (2D) materials. The newly discovered GaP and InP layers were selected as an example to demonstrate how to explore new 2D materials using computational simulations. The performance of phosphorene as the anode material of Lithium-ion battery was discussed as the example of the application of 2D material. Furthermore, the semi-empirical Hamiltonian for phosphorous and lithium elements have been developed for our future work on the application of phosphorus and lithium-based systems. The novel 2D materials of GaP and InP binary compounds were found …

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Investigating The Unique Reactivity Of Novel Hx (X=Cl, Br) Reagents With Alkenes And Alkynes., Rene E. Ebule Dec 2018

Investigating The Unique Reactivity Of Novel Hx (X=Cl, Br) Reagents With Alkenes And Alkynes., Rene E. Ebule

Electronic Theses and Dissertations

The addition of hydrogen halides to carbon-carbon unsaturated systems is a classic synthetic transformation that gives rise to a variety of halogenated products as well as building blocks.1 The different routes to achieve hydrohalogenation make use of the hydrogen halides either in the gaseous form2 or in solution3, or their surrogates4. Only second to dihalogens, hydrogen halides are the most atom efficient source of halogenation. However, hydrogen halides are reactive gases at ambient temperature, posing a major challenge in their application. Handling gaseous hydrogen halide reagents requires expert knowledge and specialized equipment. We have …

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A Transfer Learning Approach For Sentiment Classification., Omar Abdelwahab Dec 2018

A Transfer Learning Approach For Sentiment Classification., Omar Abdelwahab

Electronic Theses and Dissertations

The idea of developing machine learning systems or Artificial Intelligence agents that would learn from different tasks and be able to accumulate that knowledge with time so that it functions successfully on a new task that it has not seen before is an idea and a research area that is still being explored. In this work, we will lay out an algorithm that allows a machine learning system or an AI agent to learn from k different domains then uses some or no data from the new task for the system to perform strongly on that new task. In order …

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The Regional Distribution And Molecular Interactions Of Phospholipids And Glucose In Mammalian Vitreous Humors., Abigail Nicole Schnepf Dec 2018

The Regional Distribution And Molecular Interactions Of Phospholipids And Glucose In Mammalian Vitreous Humors., Abigail Nicole Schnepf

Electronic Theses and Dissertations

The vitreous humor (VH) is located in between the lens and the retina. It is composed of 98% water, hyaluronan (HA), collagen, proteins, phospholipids (PLs), and other metabolites. With aging, the VH undergoes liquefaction, a process that causes the gel-like structure of the VH to turn into a liquid and can lead to serious ocular diseases, including retinal detachment, vitreal detachment, and macular hole formation. The liquefaction process is expedited in diabetic VHs. This project focuses on understanding the molecular changes that lead to liquefaction and the reasons for which this process is accelerated with diabetes. Matrix-assisted laser desorption ionization/mass …

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The Causes Of The Red Sequence, The Blue Cloud, The Green Valley, And The Green Mountain, Stephen A. Eales, Maarten Baes, Nathan Bourne, Malcolm Bremer, Michael J.I. Brown, Christopher Clark, David Clements, Pieter De Vis, Simon Driver, Loretta Dunne, Simon Dye, Cristina Furlanetto, Benne W. Holwerda, R. J. Ivison, L. S. Kelvin, Maritza Lara-Lopez, Lerothodi Leeuw, Jon Loveday, Steve Maddox, Michal J. Michalowski, Steven Phillipps, Aaron Robotham, Dan Smith, Matthew Smith, Elisabetta Valiante, Paul Van Der Werf, Angus Wright Nov 2018

The Causes Of The Red Sequence, The Blue Cloud, The Green Valley, And The Green Mountain, Stephen A. Eales, Maarten Baes, Nathan Bourne, Malcolm Bremer, Michael J.I. Brown, Christopher Clark, David Clements, Pieter De Vis, Simon Driver, Loretta Dunne, Simon Dye, Cristina Furlanetto, Benne W. Holwerda, R. J. Ivison, L. S. Kelvin, Maritza Lara-Lopez, Lerothodi Leeuw, Jon Loveday, Steve Maddox, Michal J. Michalowski, Steven Phillipps, Aaron Robotham, Dan Smith, Matthew Smith, Elisabetta Valiante, Paul Van Der Werf, Angus Wright

Faculty Scholarship

The galaxies found in optical surveys fall in two distinct regions of a diagram of optical colour versus absolute magnitude: the red sequence and the blue cloud, with the green valley in between. We show that the galaxies found in a submillimetre survey have almost the opposite distribution in this diagram, forming a 'green mountain'. We show that these distinctive distributions follow naturally from a single, continuous, curved Galaxy Sequence in a diagram of specific star formation rate versus stellar mass, without there being the need for a separate star-forming galaxy main sequence and region of passive galaxies. The cause …

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The Bright-End Galaxy Candidates At Z ∼ 9 From 79 Independent Hst Fields, T. Morishita, M. Trenti, M. Stiavelli, L. D. Bradley, D. Coe, P. A. Oesch, C. A. Mason, J. S. Bridge, Benne W. Holwerda, R. C. Livermore, B. Salmon, K. B. Schmidt, J. M. Shull, T. Treu Nov 2018

The Bright-End Galaxy Candidates At Z ∼ 9 From 79 Independent Hst Fields, T. Morishita, M. Trenti, M. Stiavelli, L. D. Bradley, D. Coe, P. A. Oesch, C. A. Mason, J. S. Bridge, Benne W. Holwerda, R. C. Livermore, B. Salmon, K. B. Schmidt, J. M. Shull, T. Treu

Faculty Scholarship

We present a full data analysis of the pure-parallel Hubble Space Telescope (HST) imaging observations in the Brightest of Reionizing Galaxies Survey (BoRG[z9]) in Cycle 22. The medium-deep exposures with five HST/WFC3IR+UVIS filter bands from 79 independent sightlines (∼370 arcmin2) provide the least biased determination of number density for z 9 bright galaxies against cosmic variance. After a strict two-step selection for candidate galaxies, including dropout color and photometric redshift analyses, and revision of previous BoRG candidates, we identify one source at z ∼ 10 and two sources at z ∼ 9. The z ∼ 10 candidate shows evidence of …

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Galaxy And Mass Assembly (Gama): Accurate Number Densities And Environments Of Massive Ultra-Compact Galaxies At 0.02 < Z < 0.3, F. Buitrago, I. Ferreras, L. S. Kelvin, I. K. Baldry, L. Davies, J. Angthopo, S. Khochfar, A. M. Hopkins, S. P. Driver, S. Brough, J. Sabater, C. J. Conselice, J. Liske, Benne W. Holwerda, M. N. Bremer, S. Phillipps, A. R. López-Sánchez, A. W. Graham Nov 2018

Galaxy And Mass Assembly (Gama): Accurate Number Densities And Environments Of Massive Ultra-Compact Galaxies At 0.02 < Z < 0.3, F. Buitrago, I. Ferreras, L. S. Kelvin, I. K. Baldry, L. Davies, J. Angthopo, S. Khochfar, A. M. Hopkins, S. P. Driver, S. Brough, J. Sabater, C. J. Conselice, J. Liske, Benne W. Holwerda, M. N. Bremer, S. Phillipps, A. R. López-Sánchez, A. W. Graham

Faculty Scholarship

Context. Massive ultra-compact galaxies (MUGs) are common at z = 2-3, but very rare in the nearby Universe. Simulations predict that the few surviving MUGs should reside in galaxy clusters, whose large relative velocities prevent them from merging, thus maintaining their original properties (namely stellar populations, masses, sizes and dynamical state). Aims. Our goal is to obtain a complete census of the MUG population at 0.02 < z < 0.3, determining the number density, population properties and environment. Methods. We have taken advantage of the high-completeness, large-area spectroscopic GAMA survey, complementing it with deeper imaging from the KiDS and VIKING surveys. We find a set of 22 bona-fide MUGs, defined as having high stellar mass (> 8 × 1010 M™) and compact size (Re < 2 kpc). An additional set of seven lower-mass objects (6 × 1010 < Ma/M™ < 8 × 1010) are also potential candidates according to typical mass uncertainties. Results. The comoving number density of MUGs at low redshift (z < 0.3) is constrained at (1.0 ± 0.4)×10-6 Mpc-3, consistent with galaxy evolution models. However, we find a mixed distribution of old and young galaxies, with a quarter of the sample representing (old) relics. MUGs have a predominantly early or swollen disk morphology (Sérsic index 1 < n < 2.5) with high stellar surface densities (â Σea ∼1010 M™ Kpc-2). Interestingly, a large fraction feature close companions- A t least in projection-suggesting that many (but not all) reside in the central regions of groups. Halo masses show these galaxies inhabit average-mass groups. Conclusions. As MUGs are found to be almost equally distributed among environments of different masses, their relative fraction is higher in more massive overdensities, matching the expectations that some of these galaxies fell in these regions at early times. However, there must be another channel leading some of these galaxies to an abnormally low merger history because our sample shows a number of objects that do not inhabit particularly dense environments.

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Deep Extragalactic Visible Legacy Survey (Devils): Motivation, Design, And Target Catalogue, L. J.M. Davies, A. S.G. Robotham, S. P. Driver, C. P. Lagos, L. Cortese, E. Mannering, C. Foster, C. Lidman, A. Hashemizadeh, S. Koushan, S. O'Toole, I. K. Baldry, M. Bilicki, J. Bland-Hawthorn, M. N. Bremer, M. J.I. Brown, J. J. Bryant, B. Catinella, S. M. Croom, M. W. Grootes, Benne W. Holwerda, M. J. Jarvis, N. Maddox, M. Meyer, A. J. Moffett, S. Phillipps, E. N. Taylor, R. A. Windhorst, C. Wolf Oct 2018

Deep Extragalactic Visible Legacy Survey (Devils): Motivation, Design, And Target Catalogue, L. J.M. Davies, A. S.G. Robotham, S. P. Driver, C. P. Lagos, L. Cortese, E. Mannering, C. Foster, C. Lidman, A. Hashemizadeh, S. Koushan, S. O'Toole, I. K. Baldry, M. Bilicki, J. Bland-Hawthorn, M. N. Bremer, M. J.I. Brown, J. J. Bryant, B. Catinella, S. M. Croom, M. W. Grootes, Benne W. Holwerda, M. J. Jarvis, N. Maddox, M. Meyer, A. J. Moffett, S. Phillipps, E. N. Taylor, R. A. Windhorst, C. Wolf

Faculty Scholarship

The Deep Extragalactic VIsible Legacy Survey (DEVILS) is a large spectroscopic campaign at the Anglo-Australian Telescope (AAT) aimed at bridging the near and distant Universe by producing the highest completeness survey of galaxies and groups at intermediate redshifts (0.3 < z < 1.0). Our sample consists of ~60 000 galaxies to Y < 21.2mag, over ~6 deg2 in threewell-studied deep extragalactic fields (Cosmic Origins Survey field, COSMOS; Extended Chandra Deep Field South, ECDFS; and the X-ray Multi-Mirror Mission Large-Scale Structure region, XMM-LSS - all Large Synoptic Survey Telescope deep-drill fields). This paper presents the broad experimental design of DEVILS. Our target sample has been selected from deep Visible and Infrared Survey Telescope for Astronomy (VISTA) Y-band imaging (VISTA Deep Extragalactic Observations, VIDEO and UltraVISTA), with photometry measured by PROFOUND. Photometric star/galaxy separation is done on the basis of near-infrared colours and has been validated by visual inspection. To maximize our observing efficiency for faint targets, we employ a redshift feedback strategy, which continually updates our target lists, feeding back the results from the previous night's observations. We also present an overview of the initial spectroscopic observations undertaken in late 2017 and early 2018.

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Galaxy And Mass Assembly (Gama): The Environmental Dependence Of The Galaxy Main Sequence, L. Wang, P. Norberg, S. Brough, M. J.I. Brown, E. Da Cunha, L. J. Davies, S. P. Driver, Benne W. Holwerda, A. M. Hopkins, M. A. Lara-Lopez, J. Liske, J. Loveday, M. W. Grootes, C. C. Popescu, A. H. Wright Oct 2018

Galaxy And Mass Assembly (Gama): The Environmental Dependence Of The Galaxy Main Sequence, L. Wang, P. Norberg, S. Brough, M. J.I. Brown, E. Da Cunha, L. J. Davies, S. P. Driver, Benne W. Holwerda, A. M. Hopkins, M. A. Lara-Lopez, J. Liske, J. Loveday, M. W. Grootes, C. C. Popescu, A. H. Wright

Faculty Scholarship

Aims: We aim to investigate if the environment (characterised by the host dark matter halo mass) plays any role in shaping the galaxy star formation main sequence (MS). Methods: The Galaxy and Mass Assembly project (GAMA) combines a spectroscopic survey with photometric information in 21 bands from the far-ultraviolet (FUV) to the far-infrared (FIR). Stellar masses and dust-corrected star-formation rates (SFR) are derived from spectral energy distribution (SED) modelling using MAGPHYS. We use the GAMA galaxy group catalogue to examine the variation of the fraction of star-forming galaxies (SFG) and properties of the MS with respect to the environment. Results: …

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Galaxy And Mass Assembly (Gama): The Signatures Of Galaxy Interactions As Viewed From Small-Scale Galaxy Clustering, M. L.P. Gunawardhana, P. Norberg, I. Zehavi, D. J. Farrow, J. Loveday, A. M. Hopkins, L. J.M. Davies, L. Wang, M. Alpaslan, J. Bland-Hawthorn, S. Brough, Benne W. Holwerda, M. S. Owers, A. H. Wright Sep 2018

Galaxy And Mass Assembly (Gama): The Signatures Of Galaxy Interactions As Viewed From Small-Scale Galaxy Clustering, M. L.P. Gunawardhana, P. Norberg, I. Zehavi, D. J. Farrow, J. Loveday, A. M. Hopkins, L. J.M. Davies, L. Wang, M. Alpaslan, J. Bland-Hawthorn, S. Brough, Benne W. Holwerda, M. S. Owers, A. H. Wright

Faculty Scholarship

Statistical studies of galaxy-galaxy interactions often utilize net change in physical properties of progenitors as a function of the separation between their nuclei to trace both the strength and the observable time-scale of their interaction. In this study, we use two-point auto-, cross-, and mark-correlation functions to investigate the extent to which small-scale clustering properties of star-forming galaxies can be used to gain physical insight into galaxy-galaxy interactions between galaxies of similar optical brightness and stellar mass. The Ha star formers, drawn from the highly spatially complete Galaxy And Mass Assembly (GAMA) survey, show an increase in clustering at small …

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Plasma Based Synthesis And Surface Modification Of Graphene., Rong Zhao Aug 2018

Plasma Based Synthesis And Surface Modification Of Graphene., Rong Zhao

Electronic Theses and Dissertations

Graphene, an atom thick layer of carbon, has attracted intense scientific interest due to its exceptional electrical, mechanical and chemical properties. Especially, it provides a perfect platform to explore the unique electronic properties in absolute two-dimension. Pristine graphene possesses zero band gap and weakens its competitiveness in the field of semiconductors. In order to induce a band gap and control its semiconducting properties, functionalization and doping are two of the most feasible methods. In the context of functionalization, large area monolayer graphene synthesized by chemical vapor deposition was subjected to controlled and sequential fluorination using radio frequency plasma while monitoring …

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Bayesian Analytical Approaches For Metabolomics : A Novel Method For Molecular Structure-Informed Metabolite Interaction Modeling, A Novel Diagnostic Model For Differentiating Myocardial Infarction Type, And Approaches For Compound Identification Given Mass Spectrometry Data., Patrick J. Trainor Aug 2018

Bayesian Analytical Approaches For Metabolomics : A Novel Method For Molecular Structure-Informed Metabolite Interaction Modeling, A Novel Diagnostic Model For Differentiating Myocardial Infarction Type, And Approaches For Compound Identification Given Mass Spectrometry Data., Patrick J. Trainor

Electronic Theses and Dissertations

Metabolomics, the study of small molecules in biological systems, has enjoyed great success in enabling researchers to examine disease-associated metabolic dysregulation and has been utilized for the discovery biomarkers of disease and phenotypic states. In spite of recent technological advances in the analytical platforms utilized in metabolomics and the proliferation of tools for the analysis of metabolomics data, significant challenges in metabolomics data analyses remain. In this dissertation, we present three of these challenges and Bayesian methodological solutions for each. In the first part we develop a new methodology to serve a basis for making higher order inferences in metabolomics, …

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Generalized Spatiotemporal Modeling And Causal Inference For Assessing Treatment Effects For Multiple Groups For Ordinal Outcome., Soutik Ghosal Aug 2018

Generalized Spatiotemporal Modeling And Causal Inference For Assessing Treatment Effects For Multiple Groups For Ordinal Outcome., Soutik Ghosal

Electronic Theses and Dissertations

This dissertation consists of three projects and can be categorized in two broad research areas: generalized spatiotemporal modeling and causal inference based on observational data. In the first project, I introduce a Bayesian hierarchical mixed effect hurdle model with a nested random effect structure to model the count for primary care providers and understand their spatial and temporal variation. This study further enables us to identify the health professional shortage areas and the possible impacting factors. In the second project, I have unified popular parametric and nonparametric propensity score-based methods to assess the treatment effect of multiple groups for ordinal …

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Information Theoretic Thresholding Techniques Based On Particle Swarm Optimization., Surina Surina Aug 2018

Information Theoretic Thresholding Techniques Based On Particle Swarm Optimization., Surina Surina

Electronic Theses and Dissertations

In this dissertation, we discuss multi-level image thresholding techniques based on information theoretic entropies. In order to apply the correlation information of neighboring pixels of an image to obtain better segmentation results, we propose several multi-level thresholding models by using Gray-Level & Local-Average histogram (GLLA) and Gray-Level & Local-Variance histogram (GLLV). Firstly, a RGB color image thresholding model based on GLLA histogram and Tsallis-Havrda-Charv'at entropy is discussed. We validate the multi-level thresholding criterion function by using mathematical induction. For each component image, we assign the mean value from each thresholded class to obtain three segmented component images independently. Then we …

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High Dynamic Range Optical Devices And Applications., Elijah Robert Jensen Aug 2018

High Dynamic Range Optical Devices And Applications., Elijah Robert Jensen

Electronic Theses and Dissertations

Much of what we know about fundamental physical law and the universe derives from observations and measurements using optical methods. The passive use of the electromagnetic spectrum can be the best way of studying physical phenomenon in general with minimal disturbance of the system in the process. While for many applications ambient visible light is sufficient, light outside of the visible range may convey more information. The signals of interest are also often a small fraction of the background, and their changes occur on time scales so quickly that they are visually imperceptible. This thesis reports techniques and technologies developed …

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Evaluation Of Drug-Loaded Gold Nanoparticle Cytotoxicity As A Function Of Tumor Tissue Heterogeneity., Hunter Allan Miller Aug 2018

Evaluation Of Drug-Loaded Gold Nanoparticle Cytotoxicity As A Function Of Tumor Tissue Heterogeneity., Hunter Allan Miller

Electronic Theses and Dissertations

The inherent heterogeneity of tumor tissue presents a major challenge to nanoparticle-medicated drug delivery. This heterogeneity spans from the molecular to the cellular (cell types) and to the tissue (vasculature, extra-cellular matrix) scales. Here we employ computational modeling to evaluate therapeutic response as a function of vascular-induced tumor tissue heterogeneity. Using data with three-layered gold nanoparticles loaded with cisplatin, nanotherapy is simulated with different levels of tissue heterogeneity, and the treatment response is measured in terms of tumor regression. The results show that tumor vascular density non-trivially influences the nanoparticle uptake and washout, and the associated tissue response. The drug …

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Factorization In Integral Domains., Ryan H. Gipson Aug 2018

Factorization In Integral Domains., Ryan H. Gipson

Electronic Theses and Dissertations

We investigate the atomicity and the AP property of the semigroup rings F[X; M], where F is a field, X is a variable and M is a submonoid of the additive monoid of nonnegative rational numbers. In this endeavor, we introduce the following notions: essential generators of M and elements of height (0, 0, 0, . . .) within a cancellative torsion-free monoid Γ. By considering the latter, we are able to determine the irreducibility of certain binomials of the form Xπ − 1, where π is of height (0, 0, 0, . . .), in the monoid domain. Finally, …

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Developments In Multivariate Post Quantum Cryptography., Jeremy Robert Vates Aug 2018

Developments In Multivariate Post Quantum Cryptography., Jeremy Robert Vates

Electronic Theses and Dissertations

Ever since Shor's algorithm was introduced in 1994, cryptographers have been working to develop cryptosystems that can resist known quantum computer attacks. This push for quantum attack resistant schemes is known as post quantum cryptography. Specifically, my contributions to post quantum cryptography has been to the family of schemes known as Multivariate Public Key Cryptography (MPKC), which is a very attractive candidate for digital signature standardization in the post quantum collective for a wide variety of applications. In this document I will be providing all necessary background to fully understand MPKC and post quantum cryptography as a whole. Then, I …

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Hst Follow-Up Observations Of Two Bright Z ∼ 8 Candidate Galaxies From The Borg Pure-Parallel Survey, R. C. Livermore, M. Trenti, L. D. Bradley, S. R. Bernard, Benne W. Holwerda, C. A. Mason, T. Treu Jul 2018

Hst Follow-Up Observations Of Two Bright Z ∼ 8 Candidate Galaxies From The Borg Pure-Parallel Survey, R. C. Livermore, M. Trenti, L. D. Bradley, S. R. Bernard, Benne W. Holwerda, C. A. Mason, T. Treu

Faculty Scholarship

We present follow-up imaging of two bright (L > L∗) galaxy candidates at z ≳ 8 from the Brightest of Reionizing Galaxies (BoRG) survey with the F098M filter on the Hubble Space Telescope/Wide Field Camera 3 (HST/WFC3). The F098M filter provides an additional constraint on the flux blueward of the spectral break, and the observations are designed to discriminate between low- and high-z photometric redshift solutions for these galaxies. Our results confirm one galaxy, BoRG-0116+1425-747, as a highly probable z ∼ 8 source, but reveal that BoRG-0116+1425-630 - previously the brightest known z > 8 candidate (m AB = 24.5) - is …

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Galaxy And Mass Assembly (Gama): Variation In Galaxy Structure Across The Green Valley, Lee S. Kelvin, Malcolm N. Bremer, Steven Phillipps, Philip A. James, Luke J.M. Davies, Roberto De Propris, Amanda J. Moffett, Susan M. Percival, Ivan K. Baldry, Chris A. Collins, Mehmet Alpaslan, Joss Bland-Hawthorn, Sarah Brough, Michelle Cluver, Simon P. Driver, Abdolhosein Hashemizadeh, Benne W. Holwerda, Jarkko Laine, Maritza A. Lara-Lopez, Jochen Liske, Witold Maciejewski, Nicola R. Napolitano, Samantha J. Penny, Cristina C. Popescu, Anne E. Sansom, Will Sutherland, Edward N. Taylor, Eelco Van Kampen, Lingyu Wang Jul 2018

Galaxy And Mass Assembly (Gama): Variation In Galaxy Structure Across The Green Valley, Lee S. Kelvin, Malcolm N. Bremer, Steven Phillipps, Philip A. James, Luke J.M. Davies, Roberto De Propris, Amanda J. Moffett, Susan M. Percival, Ivan K. Baldry, Chris A. Collins, Mehmet Alpaslan, Joss Bland-Hawthorn, Sarah Brough, Michelle Cluver, Simon P. Driver, Abdolhosein Hashemizadeh, Benne W. Holwerda, Jarkko Laine, Maritza A. Lara-Lopez, Jochen Liske, Witold Maciejewski, Nicola R. Napolitano, Samantha J. Penny, Cristina C. Popescu, Anne E. Sansom, Will Sutherland, Edward N. Taylor, Eelco Van Kampen, Lingyu Wang

Faculty Scholarship

Using a sample of 472 local Universe (z < 0.06) galaxies in the stellar mass range 10.25 < logM*/M⊙ < 10.75, we explore the variation in galaxy structure as a function of morphology and galaxy colour. Our sample of galaxies is subdivided into red, green, and blue colour groups and into elliptical and non-elliptical (disk-type) morphologies. Using Kilo- Degree Survey (KiDS) and Visible and Infrared Survey Telescope for Astronomy (VISTA) Kilo-Degree Infrared Galaxy Survey (VIKING) derived postage stamp images, a group of eight volunteers visually classified bars, rings, morphological lenses, tidal streams, shells, and signs of merger activity for all systems. We find a significant surplus of rings (2.3s) and lenses (2.9s) in disk-type galaxies as they transition across the green valley. Combined, this implies a joint ring/lens green valley surplus significance of 3.3s relative to equivalent disk-types within either the blue cloud or the red sequence. We recover a bar fraction of ~44 per cent which remains flat with colour, however, we find that the presence of a bar acts to modulate the incidence of rings and (to a lesser extent) lenses, with rings in barred disk-type galaxies more common by ~20-30 percentage points relative to their unbarred counterparts, regardless of colour. Additionally, green valley disk-type galaxies with a bar exhibit a significant 3.0s surplus of lenses relative to their blue/red analogues. The existence of such structures rules out violent transformative events as the primary end-of-life evolutionary mechanism, with a more passive scenario the favoured candidate for the majority of galaxies rapidly transitioning across the green valley.

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Galaxy And Mass Assembly (Gama): Gas Fuelling Of Spiral Galaxies In The Local Universe Ii. - Direct Measurement Of The Dependencies On Redshift And Host Halo Mass Of Stellar Mass Growth In Central Disc Galaxies, M. W. Grootes, A. Dvornik, R. J. Laureijs, R. J. Tuffs, C. C. Popescu, A. S.G. Robotham, J. Liske, M. J.I. Brown, Benne W. Holwerda, L. Wang Jun 2018

Galaxy And Mass Assembly (Gama): Gas Fuelling Of Spiral Galaxies In The Local Universe Ii. - Direct Measurement Of The Dependencies On Redshift And Host Halo Mass Of Stellar Mass Growth In Central Disc Galaxies, M. W. Grootes, A. Dvornik, R. J. Laureijs, R. J. Tuffs, C. C. Popescu, A. S.G. Robotham, J. Liske, M. J.I. Brown, Benne W. Holwerda, L. Wang

Faculty Scholarship

We present a detailed analysis of the specific star formation rate-stellar mass (sSFR-M*) of z ≤ 0.13 disc central galaxies using a morphologically selected mass-complete sample (M* ≥ 109.5M⊙). Considering samples of grouped and ungrouped galaxies, we find the sSFR-M* relations of disc-dominated central galaxies to have no detectable dependence on host dark-matter halo (DMH) mass, even where weak-lensing measurements indicate a difference in halo mass of a factor ≳ 5.We further detect a gradual evolution of the sSFR-M* relation of non-grouped (field) central disc galaxies with redshift, even over a Δz ≈ 0.04 (≈5 × 108 yr) interval, while …

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Correlation Between Agricultural Land Cover And Groundwater Nitrate Contamination In Big Bat Cave, Kentucky., Brandt T. Coleman May 2018

Correlation Between Agricultural Land Cover And Groundwater Nitrate Contamination In Big Bat Cave, Kentucky., Brandt T. Coleman

College of Arts & Sciences Senior Honors Theses

No abstract provided.

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Multi Self-Adapting Particle Swarm Optimization Algorithm (Msapso)., Gerhard Koch May 2018

Multi Self-Adapting Particle Swarm Optimization Algorithm (Msapso)., Gerhard Koch

Electronic Theses and Dissertations

The performance and stability of the Particle Swarm Optimization algorithm depends on parameters that are typically tuned manually or adapted based on knowledge from empirical parameter studies. Such parameter selection is ineffectual when faced with a broad range of problem types, which often hinders the adoption of PSO to real world problems. This dissertation develops a dynamic self-optimization approach for the respective parameters (inertia weight, social and cognition). The effects of self-adaption for the optimal balance between superior performance (convergence) and the robustness (divergence) of the algorithm with regard to both simple and complex benchmark functions is investigated. This work …

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Photonic Tools For Advanced Sensing And Imaging At The Nanoscale., Jafar Hamed Ghithan May 2018

Photonic Tools For Advanced Sensing And Imaging At The Nanoscale., Jafar Hamed Ghithan

Electronic Theses and Dissertations

This dissertation reports a novel bio-sensing strategy based on single-mode, electro-active, integrated optical waveguide (SM-EA-IOW) platforms. It also reports the development of a super-resolved far-field optical imaging tool to enable optical, electronic, and spectroelectrochemical investigations at the nanoscale. SM-EA-IOW platforms with its outstanding sensitivity for spectroelectrochemical interrogation was combined with a sandwich bioassay for the development of a novel immunosensing based strategy for label-free detection of infectious pathogens. The strategy begins with the functionalization of the electroactive waveguide surface with a capturing antibody aimed at a specific target analyte. Once the target analyte is bound to the photonic interface, it …

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Potential For Developing Run-Of-River Systems In Eastern Kentucky : A Gis Approach To Site Suitability., Thomas Jeffords May 2018

Potential For Developing Run-Of-River Systems In Eastern Kentucky : A Gis Approach To Site Suitability., Thomas Jeffords

Electronic Theses and Dissertations

Coal has a questionable future with the potential exhaustion of available coal. Alternate sources of energy production should be considered, such as hydropower dams, or the more environmentally friendly, Run of River (RoR) hydropower system. This study seeks to answer the question: What is the potential for RoR hydroelectric systems in Eastern Kentucky counties with significant decreases in coal production and employment? I hypothesize that GIS will identify suitable sites within Pike County for RoR systems. Site suitability for Eastern Kentucky was assessed and determined that Pike County did not have a suitable physical environment for RoR systems. The power …

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Galaxy And Mass Assembly (Gama): Morphological Transformation Of Galaxies Across The Green Valley, M. N. Bremer, S. Phillipps, S. Kelvin, R. De Propris, Rebecca Kennedy, Amanda J. Moffett, S. Bamford, L. J.M. Davies, S. P. Driver, B. Häußler, Benne W. Holwerda, A. Hopkins, P. A. James, J. Liske, S. Percival, N. Taylor May 2018

Galaxy And Mass Assembly (Gama): Morphological Transformation Of Galaxies Across The Green Valley, M. N. Bremer, S. Phillipps, S. Kelvin, R. De Propris, Rebecca Kennedy, Amanda J. Moffett, S. Bamford, L. J.M. Davies, S. P. Driver, B. Häußler, Benne W. Holwerda, A. Hopkins, P. A. James, J. Liske, S. Percival, N. Taylor

Faculty Scholarship

We explore constraints on the joint photometric and morphological evolution of typical low redshift galaxies as they move from the blue cloud through the green valley and on to the red sequence. We select Galaxy And Mass Assembly (GAMA) survey galaxies with 10.25 < log(M*/Mo˙) < 10.75 and z < 0.2 classified according to their intrinsic u* - r* colour. From single component Śersic fits, we find that the stellar mass-sensitive K-band profiles of red and green galaxy populations are very similar while g-band profiles indicate more disc-like morphologies for the green galaxies: apparent (optical) morphological differences arise primarily from radial mass-to-light ratio variations. Two-component fits show that most green galaxies have significant bulge and disc components and that the blue to red evolution is driven by colour change in the disc. Together, these strongly suggest that galaxies evolve from blue to red through secular disc fading and that a strong bulge is present prior to any decline in star formation. The relative abundance of the green population implies a typical time-scale for traversing the green valley ~1-2 Gyr and is independent of environment, unlike that of the red and blue populations. While environment likely plays a role in triggering the passage across the green valley, it appears to have little effect on time taken. These results are consistent with a green valley population dominated by (early type) disc galaxies that are insufficiently supplied with gas to maintain previous levels of disc star formation, eventually attaining passive colours. No single event is needed to quench their star formation.

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