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Articles 1 - 14 of 14
Full-Text Articles in Physical Sciences and Mathematics
An Empirical Study Of Some Branching Processes With Upper Barrier, Alejandro Aguilar
An Empirical Study Of Some Branching Processes With Upper Barrier, Alejandro Aguilar
Theses and Dissertations - UTB/UTPA
We consider discrete time branching processes with a reflecting upper barrier. The processes differ in their offspring distributions being either binary splitting or binomial one. Two important factors for the behavior of the processes characteristics are studied as follows: time to extinction and total progeny up to the n th generation. More specifically, we investigate the distribution and expected value of the time to extinction as well as the probability mass functions of the total progeny. The tools used are basic results for a finite state Markov chain.
Dynamics For The Compound Burgers-Kdv Equation, Xiangqian Zheng
Dynamics For The Compound Burgers-Kdv Equation, Xiangqian Zheng
Theses and Dissertations - UTB/UTPA
In this thesis, we study the Two-Dimensional Burgers-Korteweg-de Vries (2D-BKdV) equation and Two-Dimensional Compound Burgers-Korteweg-de Vries (2D-Compound BKdV) by analyzing the first integral equation, which indicates that under some particular conditions, the 2D-BKdV equation and 2D-Compound BKdV have exact traveling wave solutions. By using the elliptic integral and some transformations, traveling wave solution to the 2D-BKdV equation and 2DCompound BKdV are expressed explicitly.
Prediction Of Time-To-Graduation For Stem Hispanic Undergraduate Students, Gejun Zhu
Prediction Of Time-To-Graduation For Stem Hispanic Undergraduate Students, Gejun Zhu
Theses and Dissertations - UTB/UTPA
In this thesis, we study the time-to-graduation problem for STEM Hispanic undergraduate students. The response, time-to-graduation, was treated in two different ways: as a binary variable with graduated (by the 6th year) and not-graduated values, and as an ordinal variable with values year-4, year-5, year-6, and not-graduate. Mathematics education plays critical role in students’ timely graduation, especially for STEM students. We used students records data obtained from The University of Texas-Pan American to illustrate how mathematics background factors (including SAT math score, ACT math score, TASP math score) and mathematics performance variables (including mathematics GPA, number of dropped mathematics courses, …
Balanced Modular Parameterizations, Esteban J. Melendez
Balanced Modular Parameterizations, Esteban J. Melendez
Theses and Dissertations - UTB/UTPA
In this thesis, we show that Classical representations for certain modular forms have symmetric form. These symmetric formulations are interpreted in terms of more general balanced homogeneous polynomial representations resulting from a permutative action of Hecke congruence subgroups on quotients of theta functions. For prime levels between 5 and 19, sets of permuted theta quotients are constructed that generate the corresponding vector spaces of modular forms of weight one.
Radar Image Processing And Its Applications Based On Convolution Back Projection, Qitong Li
Radar Image Processing And Its Applications Based On Convolution Back Projection, Qitong Li
Theses and Dissertations - UTB/UTPA
A general synthetic aperture radar (SAR) signal model is derived from the Maxwell’s equations, and a SAR image processing algorithm called Convolution Back Projection (CBP) will be introduced in this thesis, which can be applied to data gathered by a Synthetic Aperture Radar (SAR) system to produce high resolution images. The purpose of this thesis is starting from Maxwell’s equations to study the CBP algorithm as it is applied to SAR image processing. Two different image simulation results will be provided by this method.
Using The Differential Fay Identities For Ribbon Graph Enumeration, Indalecio Soto Jr.
Using The Differential Fay Identities For Ribbon Graph Enumeration, Indalecio Soto Jr.
Theses and Dissertations - UTB/UTPA
In this paper we are exploiting connections between the Differential Fay Identities and the partition function of Gaussian Unitary Random Matrices. The partition function has a asymptotic expression whose terms give the generating function for the enumeration of ribbon graphs partitioned by genus. These ribbon graphs (k; j), of k vertices of degree j have an orientation in genus g where the edges are represented as ribbons. Furthermore, we will develop connections between the Differential Fay Identities and introduce several theorems between the hierarchies of the identities. Lastly, we will briefly explore the first Differential Fay Identity that contains the …
The Born Approximation, Multiple Scattering, And The Butterfly Algorithm, Alejandro F. Martinez
The Born Approximation, Multiple Scattering, And The Butterfly Algorithm, Alejandro F. Martinez
Theses and Dissertations - UTB/UTPA
Radar works by focusing a beam of light and seeing how long it takes to reflect. To see a large region the beam is pointed in different directions. The focus of the beam depends on the size of the antenna (called an aperture). Synthetic aperture radar (SAR) works by moving the antenna through some region of space. A fundamental assumption in SAR is that waves only bounce once. Several imaging algorithms have been designed using that assumption. The scattering process can be described by iterations of a badly behaving integral. Recently a method for efficiently evaluating these types of integrals …
The Generation Model Of Internal Waves In A Forced Rotation-Modified Ocean, Daqi Xin
The Generation Model Of Internal Waves In A Forced Rotation-Modified Ocean, Daqi Xin
Theses and Dissertations - UTB/UTPA
A two-layer model which contains the forcing term due to the barotropic tides which flow over a comparatively large bottom topography in the ocean was derived previously. The model can be used to describe the generation of nonlinear dispersive internal tides and the following disintegration into internal waves. We studied the influence of Coriolis effect. A numerical simulation shows that the Earth’s rotation affects the generation of the internal waves since it hampers the disintegration of internal tides into internal waves.
A Screening Platform For Identification Of Compounds That Inhibit Protein Synthesis In Pseudomonas Aeruginosa, Yanmei Hu
Theses and Dissertations - UTB/UTPA
Pseudomonas aeruginosa is a Gram-negative pathogenic bacteria and a common cause of nosocomial infections. This pathogen has recently garnered attention due to its pan-resistance. We have developed a poly(U) mRNA-directed aminoacylation/translation (A/T) protein synthesis system from P. aeruginosa. The concentration of each component of the system has been arrived at through multiple rounds of optimization. Poly-phenylalanine synthesis in the system was monitored using scintillation proximity assays (SPA). This system has been used to screen two natural compound libraries (>1100) and a number of the compounds that inhibit greater than 50% of the activity of the system have been identified. …
Metal Oxide Nanostructures For Energy Conversion And Storage, Xing Sun
Metal Oxide Nanostructures For Energy Conversion And Storage, Xing Sun
Theses and Dissertations - UTB/UTPA
With the depletion of non-renewable resources and the related problems such as environmental pollutions and global warming effect, the society urgently needs more efficient and controllable energy conversion and storage systems. Three-dimensional ZnO nanoforests were prepared and morphology-tunable, which benefits both of energy conversion and storage systems. Willow-like ZnO nanoforests led the highest conversion efficiency of photoelectrochemical water splitting in reported pure ZnO nanostructures. Compared with nanowire arrays, ZnO@MnO2 nanoforests delivered 5 times higher specific capacitances within the same footprint area. V2O5@PPy exhibited higher specific capacitance and better rate stability than pure V2O5 nanofibers. This work lays the foundation for …
Monitoring Citrus Nutrition In The Rio Grande Valley For Fertilizer Recommendations, Iram Lopez
Monitoring Citrus Nutrition In The Rio Grande Valley For Fertilizer Recommendations, Iram Lopez
Theses and Dissertations - UTB/UTPA
Soil fertility and plant nutrition is crucial for a better yield and consistent harvest in the Rio Grande Valley for local farmers growing citrus trees. A field of oranges and a field of grapefruits were monitored and nutrition deficiencies were noticed that played an important role during fruit set. Soil samples that were taken throughout the year were analyzed via a carbon dioxide extraction method that mimics the way plants naturally take up nutrients or extract nutrients from every soil type. Macronutrients such as the N, P, K, Na, Ca, Mg and some of the micronutrients (Zn, Fe, Mn, and …
Cubic B-Spline: Derivation With Two Applications, Maria Mungia
Cubic B-Spline: Derivation With Two Applications, Maria Mungia
Theses and Dissertations - UTB/UTPA
We investigate the application of cubic B-spline functions in this work. First, we derive the cubic B-spline functions. Then we use these functions for two applications: one for interpolation and the other for solving boundary value problems. For interpolation, we consider two types of boundary conditions, namely natural and clamped. For boundary value problems, we consider constant coefficient and variable coefficient cases. Examples with numerical results are presented for both applications. Also we compare the results obtained using cubic B-spline functions with the results obtained by other methods. For this investigation, it is observed that cubic B-spline gives better results.
Cloning And Characterization Of Ef-Tu And Ef-Ts From Streptococcus Pneumoniae, Carlos Eduardo Rivera
Cloning And Characterization Of Ef-Tu And Ef-Ts From Streptococcus Pneumoniae, Carlos Eduardo Rivera
Theses and Dissertations - UTB/UTPA
Antibiotic resistance is a prevalent threat to public health around the world, and resistance among strains of Streptococcus pneumoniae is growing rapidly. This increasing resistance elevates the demand for new drug discoveries. This research attempts to develop a means to combat S. pneumoniae by targeting protein synthesis for the discovery of new antibacterial agents. Protein synthesis components, elongation factor Tu (EF-Tu) and elongation factor Ts (EF-Ts) facilitate many steps in the biosynthesis of proteins and are therefore essential proteins involved in protein synthesis. EF-Tu and EF-Ts were cloned, expressed, purified, and enzymatically characterized to help develop a screening system that …
Topological Pressure And Fractal Dimensions For Bi-Lipschitz Mappings, Hugo E. Olvera
Topological Pressure And Fractal Dimensions For Bi-Lipschitz Mappings, Hugo E. Olvera
Theses and Dissertations - UTB/UTPA
In this thesis, first we have defined the topological pressure P(t) and then using Banach limit we have determined a unique Borel probability measure µh supported by the invariant set E of a system of bi-Lipschitz mappings where h is the unique zero of the pressure function. Using the topological pressure and the measure µh, under certain condition on bi-Lipschitz constants, we have shown that the fractal dimensions such as the Hausdorff dimension, the packing dimension and the box-counting dimension of the set E are all equal to h. Moreover, it is shown that the h-dimensional Hausdorff measure and the …