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University of Texas Rio Grande Valley

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Articles 1891 - 1920 of 2419

Full-Text Articles in Physical Sciences and Mathematics

Cloning And Characterization Of Ef-Tu And Ef-Ts From Pseudomonas Aeruginosa, Stephanie O. Palmer, Edna Y. Rangel, Alberto E. Montalvo, Alexis T. Tran, Kate C. Ferguson, James M. Bullard Sep 2013

Cloning And Characterization Of Ef-Tu And Ef-Ts From Pseudomonas Aeruginosa, Stephanie O. Palmer, Edna Y. Rangel, Alberto E. Montalvo, Alexis T. Tran, Kate C. Ferguson, James M. Bullard

Chemistry Faculty Publications and Presentations

We have cloned genes encoding elongation factors We have cloned genes encoding elongation factors EF-Tu and EF-Ts from Pseudomonas aeruginosa and expressed and purified the proteins to greater than 95% homogeneity. Sequence analysis indicated that P. aeruginosa EF-Tu and EF-Ts are 84% and 55% identical to E. coli counterparts, respectively. P. aeruginosa EF-Tu was active when assayed in GDP exchange assays. Kinetic parameters for the interaction of EF-Tu with GDP in the absence of EF-Ts were observed to be = 33 μM, = 0.003 s−1, and the specificity constant was  s−1 μM−1. In the presence of EF-Ts, these values were …

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Facile, Green Synthesis Of Large Single Crystal Copper Micro And Nanoparticles With Ascorbic Acid And Gum Arabic, Preston B. Landon, Alexander H. Mo, Carlos T. Ramos, Jose J. Gutierrez, Ratnesh Lal Sep 2013

Facile, Green Synthesis Of Large Single Crystal Copper Micro And Nanoparticles With Ascorbic Acid And Gum Arabic, Preston B. Landon, Alexander H. Mo, Carlos T. Ramos, Jose J. Gutierrez, Ratnesh Lal

Chemistry Faculty Publications and Presentations

Large single crystal colloidal copper particles with diameters between 0.5 - 2 μm were created using a green synthesis process. The process used ascorbic acid to reduce Schweizer’s reagent created in situ using copper salts in the presence of various concentrations of gum arabic. The Schweizer’s reagents were created by varying the concentrations of ammonium hydroxide and copper nitrate solutions, copper hydroxide, or copper sulfate. The pH of the solution was controlled by the addition of ascorbic acid. Particle formation was favored at high temperature using copper sulfate at pH values ranging from 7.5 to 9, while the optimal formation …

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The Einstein@Home Search For Radio Pulsars And Psr J2007+2722 Discovery, B. Allen, B. Knispel, J. M. Cordes, J. S. Deneva, J. W.T. Hessels, D. Anderson, C. Aulbert, O. Bock, A. Brazier, S. Chatterjee, P. B. Demorest, H. B. Eggenstein, H. Fehrmann, E. V. Gotthelf, D. Hammer, V. M. Kaspi, M. Kramer, A. G. Lyne, B. Machenschalk, M. A. Mclaughlin, C. Messenger, H. J. Pletsch, S. M. Ransom, I. H. Stairs, B. W. Stappers, N. D.R. Bhat, S. Bogdanov, F. Camilo, D. J. Champion, F. Crawford Aug 2013

The Einstein@Home Search For Radio Pulsars And Psr J2007+2722 Discovery, B. Allen, B. Knispel, J. M. Cordes, J. S. Deneva, J. W.T. Hessels, D. Anderson, C. Aulbert, O. Bock, A. Brazier, S. Chatterjee, P. B. Demorest, H. B. Eggenstein, H. Fehrmann, E. V. Gotthelf, D. Hammer, V. M. Kaspi, M. Kramer, A. G. Lyne, B. Machenschalk, M. A. Mclaughlin, C. Messenger, H. J. Pletsch, S. M. Ransom, I. H. Stairs, B. W. Stappers, N. D.R. Bhat, S. Bogdanov, F. Camilo, D. J. Champion, F. Crawford

Physics and Astronomy Faculty Publications and Presentations

Einstein@Home aggregates the computer power of hundreds of thousands of volunteers from 193 countries, to search for new neutron stars using data from electromagnetic and gravitational-wave detectors. This paper presents a detailed description of the search for new radio pulsars using Pulsar ALFA survey data from the Arecibo Observatory. The enormous computing power allows this search to cover a new region of parameter space; it can detect pulsars in binary systems with orbital periods as short as 11 minutes. We also describe the first Einstein@Home discovery, the 40.8 Hz isolated pulsar PSR J2007+2722, and provide a full timing model. PSR …

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Timing Of Favorable Conditions, Competition And Fertility Interact To Govern Recruitment Of Invasive Chinese Tallow Tree In Stressful Environments, Christopher A. Gabler, Evan Siemann Aug 2013

Timing Of Favorable Conditions, Competition And Fertility Interact To Govern Recruitment Of Invasive Chinese Tallow Tree In Stressful Environments, Christopher A. Gabler, Evan Siemann

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

The rate of new exotic recruitment following removal of adult invaders (reinvasion pressure) influences restoration outcomes and costs but is highly variable and poorly understood. We hypothesize that broad variation in average reinvasion pressure of Triadica sebifera (Chinese tallow tree, a major invader) arises from differences among habitats in spatiotemporal availability of realized recruitment windows. These windows are periods of variable duration long enough to permit establishment given local environmental conditions. We tested this hypothesis via a greenhouse mesocosm experiment that quantified how the duration of favorable moisture conditions prior to flood or drought stress (window duration), competition and nutrient …

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Dynamical Behaviors Of Gonorrhea Strain Competition Model, Marisabel Rodriguez Aug 2013

Dynamical Behaviors Of Gonorrhea Strain Competition Model, Marisabel Rodriguez

Theses and Dissertations - UTB/UTPA

In the past decades, Gonorrhea, a sexually transmitted bacterial infection caused by Neisseria gonorrhoeae, has become resistant to a wider range of antibiotics. We apply a phenomenological model that takes into account essential ideas such as the effects of different treatment levels, the transformation and conjugation rates of bacteria, and the response of the immune system. Qualitative analysis provides a more integral view of how model parameters affect the emergence of within-host resistance.

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Traveling Wave Solution To Two-Dimensional Burgers-Korteweg-De Vries Equation, Xiaoqian Gong Aug 2013

Traveling Wave Solution To Two-Dimensional Burgers-Korteweg-De Vries Equation, Xiaoqian Gong

Theses and Dissertations - UTB/UTPA

In this thesis, we study the Two-Dimensional Burgers-Korteweg-de Vries (2D-BKdV) equation by analyzing the equivalent Abel equation, which indicates that under some particular conditions, the 2D-BKdV equation has a unique bounded traveling wave solution. By using the theorem of contractive mapping, a traveling wave solution to the 2D-BKdV equation is expressed explicitly. In the end, the behavior of the proper solution of the 2D-BKdV equation is established by applying the comparison theorem of differential equations.

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Accuracy Analysis Of Parallel Method Based On Non-Overlapping Domain Decomposition Method, Moonho Tak, Yooseob Song, Hye-Kwan Jeon, Taehyo Park Aug 2013

Accuracy Analysis Of Parallel Method Based On Non-Overlapping Domain Decomposition Method, Moonho Tak, Yooseob Song, Hye-Kwan Jeon, Taehyo Park

Civil Engineering Faculty Publications and Presentations

In this paper, an accuracy analysis of parallel method based on non-overlapping domain decomposition method is carried out. In this approach, proposed by Tak et al.(2013), the decomposed subdomains do not overlap each other and the connection between adjacent subdomains is determined via simple connective finite element named interfacial element. This approach has two main advantages. The first is that a direct method such as gauss elimination is available even in a singular problem because the singular stiffness matrix from floating domain can be converted to invertible matrix by assembling the interfacial element. The second is that computational time and …

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On Cubic Multisections, Andrew Alaniz Aug 2013

On Cubic Multisections, Andrew Alaniz

Theses and Dissertations - UTB/UTPA

In this thesis, a systematic procedure is given for generating cubic multi-sections of Eisenstein series. The relevant series are determined from Fourier expansions for Eisenstein series by restricting the congruence class of the summation index modulo three. The resulting series are shown to be rational functions of the Dedekind eta function. A more general treatment of cubic dissection formulas is given by describing the dissection operators in terms of linear transformations.

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Probabilistic Model And Algorithms Design For Motif Detection, Yuan Xue Aug 2013

Probabilistic Model And Algorithms Design For Motif Detection, Yuan Xue

Theses and Dissertations - UTB/UTPA

In this thesis, a natural probabilistic model has been used to test the quality of motif discovery programs. In this model, there are k background sequences, in which each character is a random character from Σ. Motif is a string G = g1g2 . . . gm. Each background sequence is implanted a probabilistically generated approximate copy of G. For each copy b1b2 . . . bm of G, every character bi is probabilistically generated such that the probability for bi 6= gi is at most α. Based on this model, two randomized algorithms ,one deterministic algorithm and one enumerative …

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Understanding User Resistance To Information Technology: Toward A Comprehensive Model In Health Information Technology, Madison N. Ngafeeson Aug 2013

Understanding User Resistance To Information Technology: Toward A Comprehensive Model In Health Information Technology, Madison N. Ngafeeson

Theses and Dissertations - UTB/UTPA

The successful implementation of health information systems is expected to increase legibility, reduce medical errors, boost the quality of healthcare and shrink costs. Yet, evidence points to the fact that healthcare professionals resist the full use of these systems. Physicians and nurses have been reported to resist the system. Even though resistance to technology has always been identified as key issue in the successful implementation of information technology, the subject remains largely under-theorized and deficient of empirical testing. Only two proposed model have been tested so far. Hence, though user resistance is clearly identified and defined in literature, not very …

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Lax Pairs For Some Nonlinear Equations, Ana Castillo Aug 2013

Lax Pairs For Some Nonlinear Equations, Ana Castillo

Theses and Dissertations - UTB/UTPA

Several methods have been proposed to approach the topic of integrable systems of nonlinear partial differential equations. One of these methods is called the Lax pair. The Lax pair is a pair of matrices or operators, that depend on time and satisfy the Lax equation. Based on the inverse scattering method introduced by Gardner, Greene, Kruskal and Miura (1967), Peter Lax introduced the Lax pair to derive soliton equations from the Lax equation. This thesis provides with a brief background on soliton theory, inverse scattering theory, and Lax pairs. The details missing in the work published by Ablowitz, Kaup, Newell, …

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Distributed Sparse Matrix Solver And Pivoting Algorithms For Large Linear Equations, Esteban Torres Aug 2013

Distributed Sparse Matrix Solver And Pivoting Algorithms For Large Linear Equations, Esteban Torres

Theses and Dissertations - UTB/UTPA

This thesis presents a distributed sparse direct solver and pivoting strategies for distributed sparse LU factorization. In Chapter I, we introduce some background concepts in linear algebra. In Chapter II, we discuss parallel hardware architectures and introduce our problem for discussion. In Chapter III, we describe the implementation of our sparse direct solver and our pivoting algorithms. Next, we present our simulation methodology and results in Chapter IV and we show that our pivoting algorithm yields up to 50% more accurate results than a current state-of-the-art solver, SuperLU_DIST. Finally, in Chapter V, we present some ideas to further improve the …

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Algorithms In Abstract Dna Self Assembly, Xingsi Zhong Aug 2013

Algorithms In Abstract Dna Self Assembly, Xingsi Zhong

Theses and Dissertations - UTB/UTPA

For the past two years, I have always been working on the topic of Abstract DNA Tiles Self-Assembly. This is a very new area, driven by the interest of DNA molecules. The feature that the system composed by DNA molecules can be a highly parallelized system, make it much more powerful when comparing with the traditional methods. This thesis will introduce the concept of abstract DNA self-assembly models as well as some interesting problems and their solutions.

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Synthetic Aperture Radar With Compressed Sensing, Yufeng Cao Aug 2013

Synthetic Aperture Radar With Compressed Sensing, Yufeng Cao

Theses and Dissertations - UTB/UTPA

A general synthetic aperture radar (SAR) signal model is derived from the Maxwell’s equations, and compressed sensing are introduced to the signal model for SAR image reconstruction. Random Partial Fourier Matrices were applied to prove that compressed sensing can be used to this signal model from the viewpoint of mathematics. In the numerical simulation part, we show that the procedure of basis pursuit can reconstruct SAR image, based on our main results, which is shown efficient in comparison with the matched filter algorithm.

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Examine Participant Dropout, Undiagnosed Diabetes And Undiagnosed Prediabetes In A Chronic Disease Prevention Education Program, Yiwen Cao Aug 2013

Examine Participant Dropout, Undiagnosed Diabetes And Undiagnosed Prediabetes In A Chronic Disease Prevention Education Program, Yiwen Cao

Theses and Dissertations - UTB/UTPA

There were 2768 participants enrolled in a chronic disease prevention education program. Survey and health measurements were obtained at three time points. We examine potential factors that might contribute to participant dropout, undiagnosed diabetes and undiagnosed prediabetes respectively. Logistic regression was used to examine the association between participant dropout and predictors, and to compare the odds of being undiagnosed with diabetes and prediabetes. We found that the potential predictors for participant dropout included age, employment, insurance, diabetes, self-reported health status, session type, program duration and curriculum. Factors affecting undiagnosed diabetes and prediabetes were age, self-reported health status birth country, limited …

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Innovation-Ict-Cybersecurity: The Triad Relationship And Its Impact On Growth Competitiveness, Manal M. Yunis Aug 2013

Innovation-Ict-Cybersecurity: The Triad Relationship And Its Impact On Growth Competitiveness, Manal M. Yunis

Theses and Dissertations - UTB/UTPA

This study examines the global growth competitiveness of countries using the dynamics of growth, ICT, and innovation. It also introduces a new dynamic, cybersecurity, and argues that within a growth competitiveness framework, ICT, innovation, and cybersecurity mechanisms allow some countries to achieve higher ranks on the competitiveness ladder than others. Based on a theoretical framework that encompasses the economic growth model, the complementarity theory, and the international law theory, a model that integrates ICT, innovation, and cybersecurity, depicts the relationships amongst them and with growth competitiveness, and incorporates complementary factors with possible moderating effect is presented. The model proposed relationships …

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Timing And Interstellar Scattering Of 35 Distant Pulsars Discovered In The Palfa Survey, D. J. Nice, E. Altiere, S. Bogdanov, J. M. Cordes, D. Farrington, J. W.T. Hessels, V. M. Kaspi, A. G. Lyne, L. Popa, S. M. Ransom, S. Sanpa-Arsa, B. W. Stappers, Y. Wang, B. Allen, N. D.R. Bhat, A. Brazier, F. Camilo, D. J. Champion, S. Chatterjee, F. Crawford, J. S. Deneva, G. Desvignes, P. C.C. Freire, F. A. Jenet, B. Knispel, P. Lazarus, K. J. Lee, J. Van Leeuwen, D. R. Lorimer, R. Lynch Jul 2013

Timing And Interstellar Scattering Of 35 Distant Pulsars Discovered In The Palfa Survey, D. J. Nice, E. Altiere, S. Bogdanov, J. M. Cordes, D. Farrington, J. W.T. Hessels, V. M. Kaspi, A. G. Lyne, L. Popa, S. M. Ransom, S. Sanpa-Arsa, B. W. Stappers, Y. Wang, B. Allen, N. D.R. Bhat, A. Brazier, F. Camilo, D. J. Champion, S. Chatterjee, F. Crawford, J. S. Deneva, G. Desvignes, P. C.C. Freire, F. A. Jenet, B. Knispel, P. Lazarus, K. J. Lee, J. Van Leeuwen, D. R. Lorimer, R. Lynch

Physics and Astronomy Faculty Publications and Presentations

We have made extensive observations of 35 distant slow (non-recycled) pulsars discovered in the ongoing Arecibo PALFA pulsar survey. Timing observations of these pulsars over several years at Arecibo Observatory and Jodrell Bank Observatory have yielded high-precision positions and measurements of rotation properties. Despite being a relatively distant population, these pulsars have properties that mirror those of the previously known pulsar population. Many of the sources exhibit timing noise, and one underwent a small glitch. We have used multifrequency data to measure the interstellar scattering properties of these pulsars. We find scattering to be higher than predicted along some lines …

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A Lover And A Fighter: The Genome Sequence Of An Entomopathogenic Nematode Heterorhabditis Bacteriophora, Xiaodong Bai, Byron J. Adams, Todd A. Ciche, Sandra Clifton, Randy Gaugler, Kwi-Suk Kim, Parwinder Grewal Jul 2013

A Lover And A Fighter: The Genome Sequence Of An Entomopathogenic Nematode Heterorhabditis Bacteriophora, Xiaodong Bai, Byron J. Adams, Todd A. Ciche, Sandra Clifton, Randy Gaugler, Kwi-Suk Kim, Parwinder Grewal

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

Heterorhabditis bacteriophora are entomopathogenic nematodes that have evolved a mutualism with Photorhabdus luminescens bacteria to function as highly virulent insect pathogens. The nematode provides a safe harbor for intestinal symbionts in soil and delivers the symbiotic bacteria into the insect blood. The symbiont provides virulence and toxins, metabolites essential for nematode reproduction, and antibiotic preservation of the insect cadaver. Approximately half of the 21,250 putative protein coding genes identified in the 77 Mbp high quality draft H. bacteriophora genome sequence were novel proteins of unknown function lacking homologs in Caenorhabditis elegans or any other sequenced organisms. Similarly, 317 of the …

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Peace: Pulsar Evaluation Algorithm For Candidate Extraction-A Software Package For Post-Analysis Processing Of Pulsar Survey Candidates, K. J. Lee, K. Stovall, F. A. Jenet, J. Martinez, L. P. Dartez, A. Mata, G. Lunsford, S. Cohen, C. M. Biwer, M. Rohr, J. Flanigan, A. Walker, S. Banaszak, B. Allen, E. D. Barr, N. D.R. Bhat, S. Bogdanov, A. Brazier, F. Camilo, D. J. Champion, S. Chatterjee, J. Cordes, F. Crawford, J. Deneva, G. Desvignes, R. D. Ferdman, P. Freire, J. W.T. Hessels, R. Karuppusamy, V. M. Kaspi Jul 2013

Peace: Pulsar Evaluation Algorithm For Candidate Extraction-A Software Package For Post-Analysis Processing Of Pulsar Survey Candidates, K. J. Lee, K. Stovall, F. A. Jenet, J. Martinez, L. P. Dartez, A. Mata, G. Lunsford, S. Cohen, C. M. Biwer, M. Rohr, J. Flanigan, A. Walker, S. Banaszak, B. Allen, E. D. Barr, N. D.R. Bhat, S. Bogdanov, A. Brazier, F. Camilo, D. J. Champion, S. Chatterjee, J. Cordes, F. Crawford, J. Deneva, G. Desvignes, R. D. Ferdman, P. Freire, J. W.T. Hessels, R. Karuppusamy, V. M. Kaspi

Physics and Astronomy Faculty Publications and Presentations

Modern radio pulsar surveys produce a large volume of prospective candidates, the majorityof which are polluted by human-created radio frequency interference or other forms of noise. Typically, large numbers of candidates need to be visually inspected in order to determineif they are real pulsars. This process can be labour intensive. In this paper, we introducean algorithm called Pulsar Evaluation Algorithm for Candidate Extraction (PEACE) whichimproves the efficiency of identifying pulsar signals. The algorithm ranks the candidates basedon a score function. Unlike popular machine-learning-based algorithms, no prior training datasets are required. This algorithm has been applied to data from several large-scale …

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Uso De Hábitat Y Perspectivas De Lontra Longicaudis En Un Área Protegida De Tamaulipas, México, Piedad Esther Mayagoitia-González, Alejandro Fierro-Cabo, Raul Valdez, Mark Andersen, David Cowley, Robert Steiner Jul 2013

Uso De Hábitat Y Perspectivas De Lontra Longicaudis En Un Área Protegida De Tamaulipas, México, Piedad Esther Mayagoitia-González, Alejandro Fierro-Cabo, Raul Valdez, Mark Andersen, David Cowley, Robert Steiner

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

El hábitat de la nutria neotropical (Lontra longicaudis) en el Área Natural Protegida (ANP) La Vega Escondida, ubicada al sur de Tamaulipas, se encuentra rodeado de un paisaje urbano en expansión. Los humedales en esta región están sometidos a una intensa presión debido a diversas actividades antropogénicas tales como la agricultura, ganadería y pesca comercial, así como construcciones y rellenos en orillas de laguna y río. El presente estudio tuvo como objetivos principales la evaluación y uso de hábitat de la nutria dentro del ANP La Vega Escondida, así como determinar la actitud de la población humana hacia esta especie. …

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Study Of The Thermodynamics Of Chromium(Iii) And Chromium(Vi) Binding To Iron(Ii/Iii)Oxide Or Magnetite Or Ferrite And Magnanese(Ii) Iron (Iii) Oxide Or Jacobsite Or Manganese Ferrite Nanoparticles, Steven Luther, Nathan Brogfeld, Jisoo Kim, Jason Parsons Jun 2013

Study Of The Thermodynamics Of Chromium(Iii) And Chromium(Vi) Binding To Iron(Ii/Iii)Oxide Or Magnetite Or Ferrite And Magnanese(Ii) Iron (Iii) Oxide Or Jacobsite Or Manganese Ferrite Nanoparticles, Steven Luther, Nathan Brogfeld, Jisoo Kim, Jason Parsons

Chemistry Faculty Publications and Presentations

Removal of chromium(III) or (VI) from aqueous solution was achieved using Fe3O4, and MnFe2O4 nanomaterials. The nanomaterials were synthesized using a precipitation method and characterized using XRD. The size of the nanomaterials was determined to be 22.4±0.9 nm (Fe3O4) and 15.5±0.5 nm (MnFe2O4). The optimal binding pH for chromium(III) and chromium(VI) were pH 6 and pH 3. Isotherm studies were performed, under light and dark conditions, to determine the capacity of the nanomaterials. The capacities for the light studies with MnFe2O4 and Fe3O4 were determined to be 7.189 and 10.63 mg/g, respectively, for chromium(III). The capacities for the light studies …

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Observation Of Asymmetric Transport In Structures With Active Nonlinearities, N. Bender, S. Factor, J. D. Bodyfelt, Hamidreza Ramezani, D. N. Christodoulides, F. M. Ellis, T. Kottos Jun 2013

Observation Of Asymmetric Transport In Structures With Active Nonlinearities, N. Bender, S. Factor, J. D. Bodyfelt, Hamidreza Ramezani, D. N. Christodoulides, F. M. Ellis, T. Kottos

Physics and Astronomy Faculty Publications and Presentations

A mechanism for asymmetric transport which is based on parity-time- symmetric nonlinearities is presented. We show that in contrast to the case of conservative nonlinearities, an increase of the complementary conductance strength leads to a simultaneous increase of asymmetry and transmittance intensity. We experimentally demonstrate the phenomenon using a pair of coupled Van der Pol oscillators as a reference system, each with complementary anharmonic gain and loss conductances, connected to transmission lines. An equivalent optical setup is also proposed. © 2013 American Physical Society.

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Hydro-Thermal Convective Solutions For An Aquifer System Heated From Below, Dambaru Bhatta Jun 2013

Hydro-Thermal Convective Solutions For An Aquifer System Heated From Below, Dambaru Bhatta

School of Mathematical and Statistical Sciences Faculty Publications and Presentations

We investigate the effect of hydro-thermal convection in an aquifer system. It is assumed that the aquifer is bounded below and above by impermeable boundaries and it is heated from below. The solution of the governing system is expressed in terms of the basic steady state solution and perturbed solution. We obtain the critical Rayleigh number and critical wavenumber using Runge-Kutta method in combination of shooting method and present the marginal stability curve. The amplitude equation is derived by introducing the adjoint system. After amplitude is obtained, we compute the linear solutions for super-critical and sub-critical cases. Numerical results for …

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Simulation Of Electronic Processes Of Nanoenergetic Gas Generator Using Cabrera Mott Oxidation Model, Zamart Ramazanova Jun 2013

Simulation Of Electronic Processes Of Nanoenergetic Gas Generator Using Cabrera Mott Oxidation Model, Zamart Ramazanova

Theses and Dissertations - UTB/UTPA

This research study is a theoretical framework for understanding rapid thermal processes which occur during the performance of new Nanoenergetic Gas-Generators (NGG) systems that rapidly release a large amount of gaseous products and generate a fast-moving thermal wave during the explosion. The kinetics of rapid oxidation of metal nanoparticles acquires practical importance with the quickly developing nanoenergetic systems. The thin film oxidation theory of Cabrera-Mott model was examined for a spherically symmetric case and used to analyze the physical importance of the exothermic processes for prediction of the reaction time and front velocity. A rapid kinetic of oxide growth on …

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Generalized Local Test For Local Extrema In Single-Variable Functions, Eleftherios Gkioulekas May 2013

Generalized Local Test For Local Extrema In Single-Variable Functions, Eleftherios Gkioulekas

School of Mathematical and Statistical Sciences Faculty Publications and Presentations

We give a detailed derivation of a generalization of the second derivative test of single-variable calculus which can classify critical points as local minima or local maxima (or neither), whenever the traditional second derivative test fails, by considering the values of higher-order derivatives evaluated at the critical points. The enhanced test is local, in the sense that it is only necessary to evaluate all relevant derivatives at the critical point itself, and it is reasonably robust. We illustrate an application of the generalized test on a trigonometric function where the second derivative test fails to classify some of the critical …

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Algebro-Geometric Solutions For The Degasperis--Procesi Hierarchy, Yu Hou, Peng Zhao, Engui Fan, Zhijun Qiao May 2013

Algebro-Geometric Solutions For The Degasperis--Procesi Hierarchy, Yu Hou, Peng Zhao, Engui Fan, Zhijun Qiao

School of Mathematical and Statistical Sciences Faculty Publications and Presentations

Though the completely integrable Camassa--Holm (CH) equation and Degasperis--Procesi (DP) equation are cast in the same peakon family, they possess the second- and third-order Lax operators, respectively. From the viewpoint of algebro-geometrical study, this difference lies in hyper-elliptic and non-hyper-elliptic curves. The non-hyper-elliptic curves lead to great difficulty in the construction of algebro-geometric solutions of the DP equation. In this paper, we derive the DP hierarchy with the help of Lenard recursion operators. Based on the characteristic polynomial of a Lax matrix for the DP hierarchy, we introduce a third order algebraic curve $\mathcal{K}_{r-2}$ with genus $r-2$, from which the …

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Biochemical, Nutrient And Inhibitory Characteristics Of Streptomyces Cultured From A Hypersaline Estuary, The Laguna Madre (Texas), Luis E. Espinoza, Anita L. Davelos Baines, Kristine L. Lowe May 2013

Biochemical, Nutrient And Inhibitory Characteristics Of Streptomyces Cultured From A Hypersaline Estuary, The Laguna Madre (Texas), Luis E. Espinoza, Anita L. Davelos Baines, Kristine L. Lowe

Biology Faculty Publications and Presentations

Streptomyces are common soil bacteria that produce secondary metabolites, including several antibiotics; however, the characteristics of marine Streptomyces are largely unknown. Sediment samples were taken from 3 sites in the Laguna Madre to isolate marine Streptomyces. Sediment was diluted, spread onto synthetic seawater media to estimate the total bacterial density of the samples and spread onto starch casein agar to isolate Streptomyces. Isolated Streptomyces were tested for salinity tolerance and optimal growth pH. Isolates were assayed using API 20E® test strips and BIOLOG™ plates to construct biochemical profiles and assess nutrient utilization abilities of the bacteria, respectively. Individual Streptomyces were …

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Compressed Sensing For Multiple Input-Multiple Output Radar Imaging, Juan F. Lopez Jr. May 2013

Compressed Sensing For Multiple Input-Multiple Output Radar Imaging, Juan F. Lopez Jr.

Theses and Dissertations - UTB/UTPA

Multiple input - multiple output (MIMO) radar utilizes the transmission of spatially diverse waveforms from a static antenna array to gather information about the desired scene. We will demonstrate how techniques from compressed sensing can be applied to image formation in MIMO radar when in the presence of undersampling. We analyze the problem under the general theoretical framework of inverse scattering.

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Electrospinning Nanofibers For Controlled Drug Release, Indrani Banik May 2013

Electrospinning Nanofibers For Controlled Drug Release, Indrani Banik

Theses and Dissertations - UTB/UTPA

Electrospinning is the most widely studied technique for the synthesis of nanofibers. Electrospinning is considered as one of the technologies that can produce nanosized drugs incorporated in polymeric nanofibers. In vitro and in vivo studies have demonstrated that the release rates of drugs from these nanofiber formulations are enhanced compared to those from original drug substance. This technology has the potential for enhancing the oral delivery of poorly soluble drugs [1]. The electrospun mats were made using Polycaprolactone/PCL, Poly(DL-lactide)/PDL 05 and Poly(DL-lactide-co-glycolide)/PLGA. The drugs incorporated in the electrospun fibers were 5-Fluorouracil and Rapamycin. The evidence of the drugs being embedded …

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Mathematical Modeling Of Two-Phase Arterial Blood Flow, Ani Emire Garcia Escorcia May 2013

Mathematical Modeling Of Two-Phase Arterial Blood Flow, Ani Emire Garcia Escorcia

Theses and Dissertations - UTB/UTPA

Problem of blood flow in an artery with or without catheter and in the presence of single or multi stenosis will be considered. The presence of stenosis locally thickens the artery wall and the use of catheter in the affected area is very important to the diagnostic and treatment of the patient. The blood flow in the arterial tube is represented by a two-phase model composing a suspension of erythrocytes in plasma. The governing equations for both fluid and particles are solved subjected to reasonable modeling and approximations. The important quantities such as blood speed, blood pressure force, impedance (blood …

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