Physical Sciences and Mathematics Commons^™

A Coherent Method For The Detection And Parameter Estimation Of Continuous Gravitational Wave Signals Using A Pulsar Timing Array, Yan Wang, Soumya D. Mohanty, F. A. Jenet

Physics & Astronomy Faculty Publications

The use of a high precision pulsar timing array is a promising approach to detecting gravitational waves in the very low frequency regime (10-6-10-9 Hz) that is complementary to ground-based efforts (e.g., LIGO, Virgo) at high frequencies (∼10-103 Hz) and space-based ones (e.g., LISA) at low frequencies (10-4-10-1 Hz). One of the target sources for pulsar timing arrays is individual supermassive black hole binaries which are expected to form in galactic mergers. In this paper, a likelihood-based method for detection and parameter estimation is presented for a monochromatic continuous gravitational wave signal emitted by such a source. The so-called pulsar …

Gravitational Waves From Individual Supermassive Black Hole Binaries In Circular Orbits: Limits From The North American Nanohertz Observatory For Gravitational Waves, Z. Arzoumanian, A. Brazier, S. Burke-Spolaor, S. J. Chamberlin, S. Chatterjee, J. M. Cordes, P. B. Demorest, X. Deng, Fredrick A. Jenet, Jing Luo

Physics & Astronomy Faculty Publications

We perform a search for continuous gravitational waves from individual supermassive black hole binaries using robust frequentist and Bayesian techniques. We augment standard pulsar timing models with the addition of time-variable dispersion measure and frequency variable pulse shape terms. We apply our techniques to the Five Year Data Release from the North American Nanohertz Observatory for Gravitational Waves. We find that there is no evidence for the presence of a detectable continuous gravitational wave; however, we can use these data to place the most constraining upper limits to date on the strength of such gravitational waves. Using the full 17 …

Optimization Of Nanograv's Time Allocation For Maximum Sensitivity To Single Sources, Brian Christy, Ryan Anella, Andrea N. Lommen, Lee Samuel Finn, Richard S. Camuccio, Emma Handzo

Physics & Astronomy Faculty Publications

Pulsar timing arrays (PTAs) are a collection of precisely timed millisecond pulsars (MSPs) that can search for gravitational waves (GWs) in the nanohertz frequency range by observing characteristic signatures in the timing residuals. The sensitivity of a PTA depends on the direction of the propagating GW source, the timing accuracy of the pulsars, and the allocation of the available observing time. The goal of this paper is to determine the optimal time allocation strategy among the MSPs in the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) for a single source of GW under a particular set of assumptions. We …

Suppression Of Optical Damage At 532 Nm In Holmium Doped Congruent Lithium Niobate, Eftihia Barnes, Nathan H. O'Connell, Nicolas R. Balli, Madhab Pokhrel, Anush Movsesyan, Edvard Kokanyan, Dhiraj K. Sardar

Physics & Astronomy Faculty Publications

Optical damage experiments were carried out in a series of Holmium doped congruent lithium niobate (Ho:cLN) crystals as a function of dopant concentration and laser intensity. The light induced beam distortion was recorded with a camera and a detector under the pseudo-Zscan configuration. At 532 nm, strong suppression of the optical damage was observed for the 0.94 mol. % doped crystal. Increased resistance to optical damage was also observed at 488 nm. The suppression of the optical damage is predominantly attributed to the reduction of the Nb antisites due to the holmium doping.

Thermodynamics, Kinetics, And Activation Energy Studies Of The Sorption Of Chromium(Iii) And Chromium(Vi) To A Mn 3 O 4 Nanomaterial, Yvette Cantu, Abril Remes, Alejandra Reyna, Denise Martinez, Jahaziel Villarreal, Hilda Ramos, Samantha Trevino, C Tamez, A Martinez, Thomas Eubanks, Jason Parsons

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

In this study, a manganese oxide, Mn3O4 was used to remove chromium(III) and chromium(VI) from aqueous solutions. The Mn3O4 nanomaterial was synthesized through a precipitation method, and was characterized using XRD, which confirmed the material had a crystal structure similar to hausmannite. In addition, using Scherrer's equation it was determined that the nanomaterial had an average grain size of 19.5 ± 1.10 nm. A study of the effects of pH on the binding of chromium(III) and chromium(VI) showed that the optimum binding pH was 4 and 3 respectively. Batch isotherm studies were performed to determine the binding capacity of chromium(III), …

Sorption Of Cr(Iii) And Cr(Vi) To High And Low Pressure Synthetic Nano-Magnetite (Fe3o4)Particles, Jason Parsons, Jeffrey Hernandez, Christina M. Gonzalez, J. L. Gardea-Torresdey

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

The binding of Cr(III) and Cr(VI) to synthetic nano-magnetie particles synthesized under open vessel conditions and a microwave assisted hydrothermal synthesis techniques was investigated. Batch studies showed that the binding of both the Cr(III) and Cr(VI) bound to the nano-materials in a pH dependent manner. The Cr(III) maximized at binding at pH 4 and 100% binding. Similarly, the Cr(VI) ions showed a maximum binding of 100% at pH 4. The data from the time dependency studies showed for the most part the majority of the binding occurred within the first 5 minutes of contact with the nanomaterial and remained constant …

A 24 Hr Global Campaign To Assess Precision Timing Of The Millisecond Pulsar J1713+0747, T. Dolch, M. T. Lam, J. Cordes, S. Chatterjee, C. Bassa, B. Bhattacharyya, D. J. Champion, I. Cognard, K. Crowter, Fredrick A. Jenet

Physics & Astronomy Faculty Publications

The radio millisecond pulsar J1713+0747 is regarded as one of the highest-precision clocks in the sky and is regularly timed for the purpose of detecting gravitational waves. The International Pulsar Timing Array Collaboration undertook a 24 hr global observation of PSR J1713+0747 in an effort to better quantify sources of timing noise in this pulsar, particularly on intermediate (1.24 hr) timescales. We observed the pulsar continuously over 24 hr with the Arecibo, Effelsberg, GMRT, Green Bank, LOFAR, Lovell, Nancay, Parkes, and WSRT radio telescopes. The combined pulse times-of-arrival presented here provide an estimate of what sources of timing noise, excluding …

First Record Of The Tropical House Gecko Hemidactylus Mabouia (Moreau De Jonnès, 1818) In Texas, Alejandro Fierro-Cabo, August Rentfro

School of Earth, Environmental, & Marine Sciences Faculty Publications

Invasions of the tropical house gecko Hemidactylus mabouia (Moreau de Jonnes, 1818) in the tropical Americas are well documented. While this gecko has been reported as well established and expanding its range in Florida, here we document the first record in the United States outside of this state. We detected a small reproducing population in Cameron County, Brownsville, Texas. We expect a rapid colonization of buildings by this species in southern Texas. We consider that this potential invasion poses novel obstacles to the continued presence of the earlier invasive Mediterranean gecko Hemidactylus turcicus (Linnaeus, 1758) across Texas

Mapping Gravitational-Wave Backgrounds Using Methods From Cmb Analysis: Application To Pulsar Timing Arrays, Jonathan Gair, Joseph D. Romano, Stephen Taylor, Chiara M. F. Mingarelli

Physics & Astronomy Faculty Publications

We describe an alternative approach to the analysis of gravitational-wave backgrounds, based on the formalism used to characterize the polarization of the cosmic microwave background. In contrast to standard analyses, this approach makes no assumptions about the nature of the background and so has the potential to reveal much more about the physical processes that generated it. An arbitrary background can be decomposed into modes whose angular dependence on the sky is given by gradients and curls of spherical harmonics. We derive the pulsar timing overlap reduction functions for the individual modes, which are given by simple combinations of spherical …

Sorption Of Cr(Iii) And Cr(Vi) To High And Low Pressure Synthetic Nano-Magnetite (Fe3o4)Particles, Jason Parsons, Jeffrey Hernandez, Christina M. Gonzalez, J. L. Gardea-Torresdey

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

The binding of Cr(III) and Cr(VI) to synthetic nano-magnetie particles synthesized under open vessel conditions and a microwave assisted hydrothermal synthesis techniques was investigated. Batch studies showed that the binding of both the Cr(III) and Cr(VI) bound to the nano-materials in a pH dependent manner. The Cr(III) maximized at binding at pH 4 and 100% binding. Similarly, the Cr(VI) ions showed a maximum binding of 100% at pH 4. The data from the time dependency studies showed for the most part the majority of the binding occurred within the first 5 minutes of contact with the nanomaterial and remained constant …

An Expeditious Green Route Toward 2-Aryl-4- Phenyl-1h-Imidazoles, Debasish Bandyopadhyay, Lauren C. Smith, Daniel R. Garcia, Ram Naresh Yadav, Bimal K. Banik

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Background: Azaheterocycles are an important class of compounds because of their highly potent medicinal activities, and the imidazole subcategory is of special interest in regard to drug discovery research.

Findings: An expeditious synthetic protocol of 2-aryl-4-phenyl-1H-imidazoles has been accomplished by reacting phenylglyoxal monohydrate, ammonium acetate, and aldehyde under sonication. Following this green approach a series of 2-aryl-4-phenyl-1H-imidazoles has been synthesized using diversely substituted aldehydes.

Conclusions: A rapid and simple synthetic procedure to synthesize diversely substituted 2-aryl-4-phenyl-1H-imidazoles has been reported. Other salient features of this protocol include milder conditions, atom-economy, easy extraction, and minimum wastes. The present procedure may find application …

On The Approximability Of The Exemplar Adjacency Number Problem For Genomes With Gene Repetitions, Zhinxiag Chen, Bin Fu, Randy Goebel, Guohui Lin, Weitian Tong, Jinhui Xu, Boting Yang, Zhiyu Zhao, Binhai Zhu

Computer Science Faculty Publications

In this paper, we apply a measure, exemplar adjacency number, which complements and extends the well-studied breakpoint distance between two permutations, to measure the similarity between two genomes (or in general, between any two sequences drawn from the same alphabet). For two genomes and drawn from the same set of n gene families and containing gene repetitions, we consider the corresponding Exemplar Adjacency Number problem (EAN), in which we delete duplicated genes from and such that the resultant exemplar genomes (permutations) G and H have the maximum adjacency number. We obtain the following results. First, we prove that the one-sided …

Energy And Potential Enstrophy Flux Constraints In Quasi-Geostrophic Models, Eleftherios Gkioulekas

School of Mathematical & Statistical Sciences Faculty Publications

We investigate an inequality constraining the energy and potential enstrophy flux spectra in two-layer and multi-layer quasi-geostrophic models. Its physical significance is that it can diagnose whether any given multi-layer model that allows co-existing downscale cascades of energy and potential enstrophy can allow the downscale energy flux to become large enough to yield a mixed energy spectrum where the dominant k−3 scaling is overtaken by a subdominant k−5/3 contribution beyond a transition wavenumber kt situated in the inertial range. The validity of the flux inequality implies that this scaling transition cannot occur within the inertial range, whereas a violation of …

Advances In Molecular Quantum Chemistry Contained In The Q-Chem 4 Program Package, Yihan Shao, Zhengting Gan, Evgeny Epifanovsky, Andrew T. B. Gilbert, Michael Wormit, Shervin Fatehi

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

A summary of the technical advances that are incorporated in the fourth major release of the Q-CHEM quantum chemistry program is provided, covering approximately the last seven years. These include developments in density functional theory methods and algorithms, nuclear magnetic resonance (NMR) property evaluation, coupled cluster and perturbation theories, methods for electronically excited and open-shell species, tools for treating extended environments, algorithms for walking on potential surfaces, analysis tools, energy and electron transfer modelling, parallel computing capabilities, and graphical user interfaces. In addition, a selection of example case studies that illustrate these capabilities is given. These include extensive benchmarks of …

Theoretical And Experimental Infrared Spectra Of Hydrated And Dehydrated Sulfonated Poly(Ether Ether Ketone), Jonathan Doan, Erin Kingston, Ian Kendrick, Kierstyn Anderson, Nicholas Dimakis, Philippe Knauth, Maria Luisa Di Vona, Eugene S. Smotkina

Physics & Astronomy Faculty Publications

Time-dependent FT-IR spectra of sulfonated poly(ether ether ketone) during dehydration show diminishing 1081 cm−1 and 1023 cm−1 band intensities concurrent with the emergence and shifting of bands at 1362 cm−1 and 898 cm−1. Animations of density functional theory calculated normal modes enable assignment of the 1081 cm−1 and 1023 cm−1 bands as group modes that include a sulfonate exchange site with C3v local symmetry, while the 1362 cm−1 and 898 cm−1 bands are assigned as group modes that include an associated sulfonic acid with no local symmetry (C1). In contrast to analogously assigned Nafion group mode bands, the SPEEK C3v …

First All-Sky Search For Continuous Gravitational Waves From Unknown Sources In Binary Systems, J. Aasi, B. P. Abbott, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov

Physics & Astronomy Faculty Publications

We present the first results of an all-sky search for continuous gravitational waves from unknown spinning neutron stars in binary systems using LIGO and Virgo data. Using a specially developed analysis program, the TwoSpect algorithm, the search was carried out on data from the sixth LIGO science run and the second and third Virgo science runs. The search covers a range of frequencies from 20 Hz to 520 Hz, a range of orbital periods from 2 to ∼2; 254 h and a frequency- and period-dependent range of frequency modulation depths from 0.277 to 100 mHz. This corresponds to a range …

Publisher’S Note: “Derivative Couplings Between Tddft Excited States Obtained By Direct Differentiation In The Tamm-Dancoff Approximation” [J. Chem. Phys. 141, 024114 (2014)], Qi Ou, Shervin Fatehi, Ethan Alguire, Yihan Shao, Joseph Subotnik

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

No abstract provided.

The Green Bank Northern Celestial Cap Pulsar Survey. I. Survey Description Data Analysis And Initial Results, Kevin Stovall, R. S. Lynch, Louis Percy Dartez, Anthony J. Ford, A. Garcia, J. Hinojosa, Fredrick A. Jenet, Sean Leake, Jose Guadalupe Martinez, Alberto Mata

Physics & Astronomy Faculty Publications

We describe an ongoing search for pulsars and dispersed pulses of radio emission, such as those from rotating radio transients (RRATs) and fast radio bursts, at 350 MHz using the Green Bank Telescope. With the Green Bank Ultimate Pulsar Processing Instrument, we record 100 MHz of bandwidth divided into 4096 channels every 81.92 μs. This survey will cover the entire sky visible to the Green Bank Telescope (δ > -40°, or 82% of the sky) and outside of the Galactic Plane will be sensitive enough to detect slow pulsars and low dispersion measure (cm-3) millisecond pulsars (MSPs) with a 0.08 duty …

Efficient Evaluation Of Sparql Property Path Queries Over Prov-Dm Provenance Graphs In An Rdbms, Rodolfo E. Roman Velasco

Theses and Dissertations - UTB/UTPA

Millions of useful resources on the Web are enhanced with machine-processable annotations using W3C Resource Description Framework (RDF). It is crucial to design efficient data management techniques to support querying of existing RDF datasets using standard SPARQL queries. To address this challenge, we use a Relational Database Management System (RDBMS) for efficient and scalable storage and querying backend for RDF data. Our solution requires designing novel algorithms for translating SPARQL queries into equivalent SQL queries, such that the latter can be efficiently executed in an RDBMS. The focus of this work is on the translation of SPARQL property paths queries. …

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, …

Exposure To Traffic Pollution, Acute Inflammation And Autonomic Response In A Panel Of Car Commuters, Jeremy A. Sarnat, Rachel Golan, Roby Greenwald, Amit U. Raysoni, Priya Kewada, Andrea Winquist, Stefanie E. Sarnat, W. Dana Flanders, Maria C. Mirabelli, Jennifer E. Zora

School of Earth, Environmental, & Marine Sciences Faculty Publications

Background

Exposure to traffic pollution has been linked to numerous adverse health endpoints. Despite this, limited data examining traffic exposures during realistic commutes and acute response exists. Objectives: We conducted the Atlanta Commuters Exposures (ACE-1) Study, an extensive panel-based exposure and health study, to measure chemically-resolved in-vehicle exposures and corresponding changes in acute oxidative stress, lipid peroxidation, pulmonary and systemic inflammation and autonomic response.

Methods

We recruited 42 adults (21 with and 21 without asthma) to conduct two 2-h scripted highway commutes during morning rush hour in the metropolitan Atlanta area. A suite of in-vehicle particulate components were measured in …

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.

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.

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.

Anxiety, Depression And Smoking Status Among Adults Of Mexican Heritage On The Texas-Mexico Border, Anna V. Wilkinson, Kristina Vatcheva, Adriana Pérez, Belinda M. Reininger, Joseph B. Mccormick, Susan P. Fisher-Hoch

School of Mathematical & Statistical Sciences Faculty Publications

The goal of the current analysis is to examine relationships between smoking status and anxiety and depression among adults of Mexican heritage to inform the development of culturally relevant smoking cessations efforts. Mexican heritage residents (N=1,791) of the city of Brownsville, TX, aged 18 years or older, enrolled in the Cameron County Hispanic Cohort, were selected through two stage cluster sampling of randomly selected census tracts from the first and third quartile of SES using Census 2000. Among current smokers, anxiety and depression scores were highest among women who had not completed high school (p<0.05). Former smoking women, but not men, with at least a high school education and former smoking women born in the United States reported higher levels of anxiety and depression than never smoking women. Negative affective states may represent a greater barrier to smoking cessation among women than men.

Fast Radio Burst Discovered In The Arecibo Pulsar Alfa Survey, L. G. Spitler, J. M. Cordes, J. W.T. Hessels, D. R. Lorimer, M. A. Mclaughlin, S. Chatterjee, F. Crawford, J. S. Deneva, Fredrick Jenet

Physics & Astronomy Faculty Publications

Recent work has exploited pulsar survey data to identify temporally isolated, millisecond-duration radio bursts with large dispersion measures (DMs). These bursts have been interpreted as arising from a population of extragalactic sources, in which case they would provide unprecedented opportunities for probing the intergalactic medium; they may also be linked to new source classes. Until now, however, all so-called fast radio bursts (FRBs) have been detected with the Parkes radio telescope and its 13-beam receiver, casting some concern about the astrophysical nature of these signals. Here we present FRB 121102, the first FRB discovery from a geographic location other than …

Illustrations And Supporting Texts For Sound Standing Waves Of Air Columns In Pipes In Introductory Physics Textbooks, Liang Zeng, Chris Smith, G. Herold Poelzer, Jennifer Rodriguez, Edgar Corpuz, George Yanev

Physics & Astronomy Faculty Publications

In our pilot studies, we found that many introductory physics textbook illustrations with supporting text for sound standing waves of air columns in open-open, open-closed, and closed-closed pipes inhibit student understanding of sound standing wave phenomena due to student misunderstanding of how air molecules move within these pipes. Based on the construct of meaningful learning from cognitive psychology and semiotics, a quasiexperimental study was conducted to investigate the comparative effectiveness of two alternative approaches to student understanding: a traditional textbook illustration approach versus a newly designed air molecule motion illustration approach. Thirty volunteer students from introductory physics classes were randomly …

Reconstruction Of Structured Quadratic Pencils From Eigenvalues On Ellipses And Parabolas, R. Ibragimov, Vesselin Vatchev

School of Mathematical & Statistical Sciences Faculty Publications

In the present paper we study the reconstruction of a structured quadratic pencil from eigenvalues distributed on ellipses or parabolas. A quadratic pencil is a square matrix polynomial

QP(λ) = M λ²+Cλ +K,

where M, C, and K are real square matrices. The approach developed in the paper is based on the theory of orthogonal polynomials on the real line. The results can be applied to more general distribution of eigenvalues. The problem with added single eigenvector is also briefly discussed. As an illustration of the reconstruction method, the eigenvalue problem …

Derivative Couplings Between Tddft Excited States Obtained By Direct Differentiation In The Tamm-Dancoff Approximation, Qi Ou, Shervin Fatehi, Ethan Alguire, Yihan Shao, Joseph Subotnik

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Working within the Tamm-Dancoff approximation, we calculate the derivative couplings between time-dependent density-functional theory excited states by assuming that the Kohn-Sham superposition of singly excited determinants represents a true electronic wavefunction. All Pulay terms are included in our derivative coupling expression. The reasonability of our approach can be established by noting that, for closely separated electronic states in the infinite basis limit, our final expres- sion agrees exactly with the Chernyak-Mukamel expression (with transition densities from response theory). Finally, we also validate our approach empirically by analyzing the behavior of the derivative couplings around the T1/T2 conical intersection of benzaldehyde.

Detection And Estimation Of Unmodeled Narrowband Nonstationary Signals: Application Of Particle Swarm Optimization In Gravitational Wave Data Analysis, Soumya Mohanty

Physics & Astronomy Faculty Publications

The extraction of weak signals from instrumental noise is a critical task in ongoing searches for gravitational waves. A detection and estimation method, made feasible by Particle Swarm Optimization, is presented for a particularly challenging class of signals expected from astrophysical sources.