Physical Sciences and Mathematics Commons^™

Search For Gravitational Wave Ringdowns From Perturbed Intermediate Mass Black Holes In Ligo-Virgo Data From 2005–2010, J. Aasi, B. P. Abbott, Matthew Benacquista, H. Daveloza, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov, Robert Stone, Cristina V. Torres

Physics & Astronomy Faculty Publications

We report results from a search for gravitational waves produced by perturbed intermediate mass black holes (IMBH) in data collected by LIGO and Virgo between 2005 and 2010. The search was sensitive to astrophysical sources that produced damped sinusoid gravitational wave signals, also known as ringdowns, with frequency 50 ≤ f0=Hz ≤ 2000 and decay timescale 0.0001 ≲ τ=s ≲ 0.1 characteristic of those produced in mergers of IMBH pairs. No significant gravitational wave candidate was detected. We report upper limits on the astrophysical coalescence rates of IMBHs with total binary mass 50 ≤ M=M⊙ ≤ 450 and component mass …

Experimental Observation Of Lasing Shutdown Via Asymmetric Gain, M. Chitsazi, S. Factor, J. Schindler, Hamidreza Ramezani, F. M. Ellis, T. Kottos

Physics & Astronomy Faculty Publications

Using a pair of coupled RLC cavities we experimentally demonstrate that amplification action can be tamed by a spatially inhomogeneous gain. Under specific conditions we observe the counterintuitive phenomenon of stabilization of the system even when the overall gain provided is increased. This behavior is directly related to lasing shutdown via asymmetric pumping, recently proposed in M. Liertzer et al. [Phys. Rev. Lett. 108, 173901 (2012)]. The analysis of other simple systems reveals the universal nature of the lasing shutdown phenomenon as having its roots in managing impedance matching.

Communication: Conical Intersections Between Vibrationally Adiabatic Surfaces In Methanol, Mahesh B. Dawadi, David S. Perry

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

A set of seven conical intersections (CI’s) in methanol between vibrationally adiabatic surfaces is reported. The intersecting surfaces represent the energies of the two asymmetric CH stretch vibrations regarded as adiabatic functions of the torsion and COH bend angles. The ab initio data are well described by an extended Zwanziger and Grant (E ⊗ e) model [J. W. Zwanziger and E. R. Grant, J. Chem. Phys. 87, 2954 (1987)] that might also be regarded as an extension of the XHL model [L.-H. Xu, J. T. Hougen, and R. M. Lees, J. Mol. Spectrosc. 293–294, 38 (2013)]. …

Optical Isolation Via Pt-Symmetric Nonlinear Fano Resonances, F. Nazari, N. Bender, Hamidreza Ramezani, M. K. Moravvej-Farshi, D. N. Christodoulides, T. Kottos

Physics & Astronomy Faculty Publications

We show that Fano resonances created by twoPT -symmetric nonlinear micro-resonators coupled to a waveguide, have line-shape and resonance position that depends on the direction of the incident light. We utilize these features in order to induce asymmetric transport, up to 47 dBs, in the optical C-window. Our theoretical proposal requires low input power and does not compromise the power or frequency characteristics of the output signal.

Gravitational Waves From Known Pulsars: Results From The Initial Detector Era, J. Aasi, J. Abadie, B. P. Abbott, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Walter Ortega Larcher, Volker Quetschke, Malik Rakhmanov, Joseph D. Romano

Physics & Astronomy Faculty Publications

We present the results of searches for gravitational waves from a large selection of pulsars using data from the most recent science runs (S6, VSR2 and VSR4) of the initial generation of interferometric gravitational wave detectors LIGO (Laser Interferometric Gravitational-wave Observatory) and Virgo. We do not see evidence for gravitational wave emission from any of the targeted sources but produce upper limits on the emission amplitude. We highlight the results from seven young pulsars with large spin-down luminosities. We reach within a factor of five of the canonical spin-down limit for all seven of these, whilst for the Crab and …

On Toroidal Knots, Chirality, And Molecules, Ramiro Garza

Theses and Dissertations - UTB/UTPA

The inspiration for this thesis came from two sources: the book When topology meets chemistry: a topological look at molecular chirality, by Erica Flapan [7], which discusses topologically interesting molecules; and the paper All toroidal embeddings of polyhedral graphs in 3-space are chiral, by T. Castle et al., which proves that toroidal embeddings of polyhedra are chiral. Their proof is examined in detail. A possible application of this work, as discussed by the team, would be in molecules which have the structure of a toroidal polyhedral embedding. Various methods of seeking such an example are attempted and discussed.

A Digital Backend For The Low Frequency All Sky Monitor, Louis Percy Dartez

Theses and Dissertations - UTB/UTPA

The Low Frequency All Sky Monitor (LoFASM) is a distributed array of dipole antennas that are sensitive to radio frequencies from 10 to 88 MHz. The primary science goals of LoFASM are the detection and study of low-frequency radio transients, a high priority science goal as deemed by the National Research Council's decadal survey. LoFASM consists of antennas and front-end electronics that were originally developed for the Long Wavelength Array (LWA) by the U.S. Naval Research Lab, the University of New Mexico, Virginia Tech, and the Jet Propulsion Laboratory. LoFASM, funded by the U.S. Department of Defense, will initially consist …

Temperature And Relative Humidity Effects On Water Loss And Hemolymph Osmolality Of Littoraria Angulifera (Lamarck, 1822), Phillip J. Rose

Theses and Dissertations - UTB/UTPA

Desiccation stress is considered to be one of the more significant determining factors that influence how organisms are distributed in the marine littoral. Gastropods living above the high tide mark, referred to as eulittoral fringe gastropods are not wetted as regularly and face unpredictable and prolonged periods of emersion. Consequently, adaptations displayed by eulittoral fringe gastropods are aimed at minimizing water loss and surviving prolonged periods of desiccation stress. Littoraria angulifera, is a tropically distributed marine eulittoral fringe gastropod. Because L. angulifera spends a majority of its time emersed there was interest in studying how the weight loss and hemolymph …

The Role Of App Development And Mobile Computing In Motivating The Secondary Mathematics Classroom, Jennifer Lee Marquez

Theses and Dissertations - UTB/UTPA

An increasing amount of high school students are interested in developing their own mobile application. Incorporating mobile development into the classroom can increase student engagement in the fields of science, technology, engineering, and mathematics. In this paper I present a study done with a group of sophomore level students who created their own mathematics apps with no programming experience. The aim of this study is to assess the knowledge gained and motivational appeal of secondary mathematics students taught basic state of Texas exam concepts with the use of the proposed mobile development labs. Students in this study used algebraic and …

Fermi-Normal, Optical, And Wave-Synchronous Coordinates For Spacetime With A Plane Gravitational Wave, Malik Rakhmanov

Physics & Astronomy Faculty Publications

Fermi-normal (FN) coordinates provide a standardized way to describe the effects of gravitation from the point of view of an inertial observer. These coordinates have always been introduced via perturbation expansions and were usually limited to distances much less than the characteristic length scale set by the curvature of spacetime. For a plane gravitational wave this scale is given by its wavelength which defines the domain of validity for these coordinates known as the long-wavelength regime. The symmetry of this spacetime, however, allows us to extend FN coordinates far beyond the long-wavelength regime. Here we present an explicit construction for …

Experimental Observation Of Lasing Shutdown Via Asymmetric Gain, M. Chitsazi, S. Factor, J. Schindler, Hamidreza Ramezani

Physics & Astronomy Faculty Publications

Using a pair of coupled RLC cavities we experimentally demonstrate that amplification action can be tamed by a spatially inhomogeneous gain. Under specific conditions we observe the counterintuitive phenomenon of stabilization of the system even when the overall gain provided is increased. This behavior is directly related to lasing shutdown via asymmetric pumping, recently proposed in M. Liertzer et al. [Phys. Rev. Lett. 108, 173901 (2012)]. The analysis of other simple systems reveals the universal nature of the lasing shutdown phenomenon as having its roots in managing impedance matching.

Prepubertal Exposure To Arsenic(Iii) Suppresses Circulating Insulin-Like Growth Factor-1 (Igf-1) Delaying Sexual Maturation In Female Rats, Michael P. Reilly, James C. Saca, Alina Hamilton, Rene F. Solano, Jesse R. Rivera, Wendy Innis-Whitehouse, Jason Parsons, Robert K. Dearth

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

Arsenic (As) is a prevalent environmental toxin readily accessible for human consumption and has been identified as an endocrine disruptor. However, it is not known what impact As has on female sexual maturation. Therefore, in the present study, we investigated the effects of prepubertal exposure on mammary gland development and pubertal onset in female rats. Results showed that prepubertal exposure to 10 mg/kg of arsenite (As(III)) delayed vaginal opening (VO) and prepubertal mammary gland maturation. We determined that As accumulates in the liver, disrupts hepatocyte function and suppresses serum levels of the puberty related hormone insulin-like growth factor 1 (IGF-1) …

Gravitational Wave Hotspots: Ranking Potential Locations Of Single-Source Gravitational Wave Emission, Joseph Simon, Abigail Polin, Andrea Lommen, Ben Stappers, Lee Samuel Finn, F. A. Jenet, B. Christy

Physics & Astronomy Faculty Publications

The steadily improving sensitivity of pulsar timing arrays (PTAs) suggests that gravitational waves (GWs) from supermassive black hole binary (SMBHB) systems in the nearby universe will be detectable sometime during the next decade. Currently, PTAs assume an equal probability of detection from every sky position, but as evidence grows for a non-isotropic distribution of sources, is there a most likely sky position for a detectable single source of GWs? In this paper, a collection of Galactic catalogs is used to calculate various metrics related to the detectability of a single GW source resolvable above a GW background, assuming that every …

Concept Of A Reflective Power Limiter Based On Nonlinear Localized Modes, Elena Makri, Hamidreza Ramezani, Tsampikos Kottos, Ilya Vitebsky

Physics & Astronomy Faculty Publications

Optical limiters are designed to transmit low-intensity light, while blocking the light with excessively high intensity. A typical passive limiter absorbs excessive electromagnetic energy, which can cause its overheating and destruction. We propose the concept of a photonic reflective limiter based on resonance transmission via a localized mode. Such a limiter does not absorb the high-level radiation, but rather reflects it back to space. Importantly, the nearly total reflection occurs within a broad frequency range and direction of incidence. The same concept can be applied to infrared and microwave frequencies.

Minisuperspace Canonical Quantization Of The Reissner-Nordström Black Hole Via Conditional Symmetries, T. Christodoulakis, Nicholas Dimakis, Petros A. Terzis, Babak Vakili, E. Melas, Th. Grammenos

Physics & Astronomy Faculty Publications

We use the conditional symmetry approach to study the r evolution of a minisuperspace spherically symmetric model both at the classical and the quantum level. After integration of the coordinates t, θ and ϕ in the gravitational plus electromagnetic action the configuration space dependent dynamical variables turn out to correspond to the r-dependent metric functions and the electrostatic field. In the context of the formalism for constrained systems (Dirac-Bergmann, Arnowitt-Deser-Misner) with respect to the radial coordinate r, we set up a pointlike reparametrization invariant Lagrangian. It is seen that, in the constant potential parametrization of the lapse, the corresponding minisuperspace …

First Searches For Optical Counterparts To Gravitational-Wave Candidate Events, M. Constancio, J. Aasi, J. Abadie, B. P. Abbott, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov, Joseph D. Romano

Physics & Astronomy Faculty Publications

During the Laser Interferometer Gravitational-wave Observatory and Virgo joint science runs in 2009-2010, gravitational wave (GW) data from three interferometer detectors were analyzed within minutes to select GW candidate events and infer their apparent sky positions. Target coordinates were transmitted to several telescopes for follow-up observations aimed at the detection of an associated optical transient. Images were obtained for eight such GW candidates. We present the methods used to analyze the image data as well as the transient search results. No optical transient was identified with a convincing association with any of these candidates, and none of the GW triggers …

Crucial Positively Charged Residues For Ligand Activation Of The Gpr35 Receptor, Pingwei Zhao, Tom R. Lane, Helen G.L. Gao, Dow P. Hurst, Evangelia Kotsikorou, Long Le, Eugen Brailoiu, Patricia H. Reggio, Mary E. Abood

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

GPR35 is a G protein-coupled receptor expressed in the immune, gastrointestinal, and nervous systems in gastric carcinomas and is implicated in heart failure and pain perception. We investigated residues in GPR35 responsible for ligand activation and the receptor structure in the active state. GPR35 contains numerous positively charged amino acids that face into the binding pocket that cluster in two distinct receptor regions, TMH3-4-5-6 and TMH1-2-7. Computer modeling implicated TMH3-4-5-6 for activation by the GPR35 agonists zaprinast and pamoic acid. Mutation results for the TMH1-2-7 region of GPR35 showed no change in ligand efficacies at the K1.32A, R2.65A, R7.33A, and …

Optimal Control In The Treatment Of Retinitis Pigmentosa, Erika T. Camacho, Luis A. Melara, Cristina Villalobos, Stephen Wirkus

School of Mathematical & Statistical Sciences Faculty Publications

Numerous therapies have been implemented in an effort to minimize the debilitating effects of the degenerative eye disease Retinitis Pigmentosa (RP), yet none have provided satisfactory long-term solution. To date there is no treatment that can halt the degeneration of photoreceptors. The recent discovery of the RdCVF protein has provided researchers with a potential therapy that could slow the secondary wave of cone death. In this work, we build on an existing mathematical model of photoreceptor interactions in the presence of RP and incorporate various treatment regiments via RdCVF. Our results show that an optimal control exists for the administration …

Personal Cloud User Acceptance: The Role Of Trust And Perceived Risk In The Technology Acceptance Model, Murad Moqbel, Valerie L. Bartelt, John Cicala

Information Systems Faculty Publications

This research considers technology adoption issues, as well as risk and trust factors, that lead to behavioral intention of personal cloud computing. We are interested in whether similar results are found in personal cloud computing, a tool that may be perceived as having more risks. Our research found that perceived risk decreased behavioral intentions. Perceived usefulness served as a mediator between trust and behavioral intentions, significantly increasing both relationships. Trust was found to decrease perceived risk; however, it directly increased behavioral intention, perceived usefulness, and perceived ease of use. Interestingly, perceived ease of use did not significantly affect behavioral intentions. …

Searching For Pulsars Using Image Pattern Recognition, W. W. Zhu, Kevin Stovall, Stephanie Cohen, Louis Percy Dartez, Grady Lunsford, Jose Guadalupe Martinez, Alberto Mata, Fredrick A. Jenet

Physics & Astronomy Faculty Publications

In the modern era of big data, many fields of astronomy are generating huge volumes of data, the analysis of which can sometimes be the limiting factor in research. Fortunately, computer scientists have developed powerful data-mining techniques that can be applied to various fields. In this paper, we present a novel artificial intelligence (AI) program that identifies pulsars from recent surveys by using image pattern recognition with deep neural nets - the PICS (Pulsar Image-based Classification System) AI. The AI mimics human experts and distinguishes pulsars from noise and interference by looking for patterns from candidate plots. Different from other …

The Mean Transform Of Bounded Linear Operators, Sang Hoon Lee, Woo Young Lee, Jasang Yoon

School of Mathematical & Statistical Sciences Faculty Publications

In this paper we introduce the mean transform of bounded linear operators acting on a complex Hilbert space and then explore how the mean transform of weighted shifts behaves, in comparison with the Aluthge transform.

On Cubic Multisections Of Eisenstein Series, Andrew Alaniz, Timothy Huber

School of Mathematical & Statistical Sciences Faculty Publications

A systematic procedure for generating cubic multisections of Eisenstein series is given. The relevant series are determined from Fourier expansions for Eisenstein series by restricting the congruence class of the summation index modulo three. We prove that the resulting series are rational functions of η(τ) and η(3τ), where η is the Dedekind eta function. A more general treatment of cubic dissection formulas is given by describing the dissection operators in terms of linear transformations. These operators exhibit properties that mirror those of similarly defined quintic operators.

Analysis Of Localized Diabatic States Beyond The Condon Approximation For Excitation Energy Transfer Processes, Ethan Alguire, Shervin Fatehi, Yihan Shao, Joseph E. Subotnik

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

In a previous paper [Fatehi, S.; et al. J. Chem. Phys. 2013, 139, 124112], we demonstrated a practical method by which analytic derivative couplings of Boys-localized CIS states can be obtained. In this paper, we now apply that same method to the analysis of triplet–triplet energy transfer systems studied by Closs and collaborators [Closs, G. L.; et al. J. Am. Chem. Soc.1988, 110, 2652]. For the systems examined, we are able to conclude that (i) the derivative coupling in the BoysOV basis is negligible, and (ii) the diabatic coupling will likely change little over the configuration space explored …

Self-Heating Model Of Spherical Aluminum Nanoparticle Oxidation, Karen S. Martirosyan, Zamart Ramazanova, Maxim Zyskin

Physics & Astronomy Faculty Publications

Aluminum-oxygen reaction is important in highly energetic and high pressure generating systems. Nanoenergetic thermites include mixtures of nanostructured Al and oxidizer particles. The main distinguishing features of these reactive systems are their significant enthalpy release and tunable rate of energy discharge, which gives rise to a wide range of combustion rates, energy release, and ignition sensitivity. In this paper, we consider rapid oxidation of a spherically symmetric aluminum particle. We use the Cabrera Mott oxidation model to describe the kinetics of oxide growth of an aluminum nanoparticle and to predict reaction temperature and oxidation time. We assume that aluminum particle …

The Cytotoxic Effect Of 2-Acylated-1,4-Naphthohydroquinones On Leukemia/Lymphoma Cells, Diego A. Pedroza, Fernando De Leon, Armando Varela-Ramirez, Carolina Lerma, Renato J. Aguilera, Shizue Mito

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

Here, we tested seven 2-acylated-1,4-hydronaphthoquinones for their cytotoxic effects on a panel of cancer lymphoma/leukemia cells and compared to a non-cancer origin cell line. Several naphthohydroquinones exhibited selective cytotoxic effects on lymphoma/leukemia cells with lowest activity on non-cancer cells. The mode of cell death induced by an acylated naphthohydroquinone, which has a long alkyl chain, was found to be via apoptosis. Furthermore, the naphthohydroquinone provoked mitochondria depolarization and activation of its downstream effector, caspase-3, thus implicating the intrinsic apoptotic pathway as its mechanism to exert cell death.

Influence Of Constant And Periodic Experimental Hypoxic Stress On Atlantic Croaker Otolith Chemistry, John Mohan, Md. Saydur Rahman, Peter Thomas, Benjamin Walther

School of Earth, Environmental, & Marine Sciences Faculty Publications

The chemical composition of fish otoliths may provide information on the environmental exposure histories of fishes if ‘vital effects’ on element incorporation are minimal. In order to use redox-sensitive geochemical proxies, such as manganese, in otoliths to quantify sublethal exposure to hypoxia, the relative influence of endogenous and exogenous controls on otolith composition must first be validated. Controlled laboratory experiments were conducted on Atlantic croaker Micropogonias undulatus to examine the response of otolith Sr:Ca, Ba:Ca, Mg:Ca, Mn:Ca, and Na:Ca ratios to either constant or periodic hypoxia treatments for 4 and 10 wk, respectively. Although fish somatic growth and condition were …

Assessing The Optimal Virulence Of Malaria‐Targeting Mosquito Pathogens: A Mathematical Study Of Engineered Metarhizium Anisopliae, Bernhard Konrad, Michael R. Lindstrom, Anja Gumpinger, Jielin Zhu, Daniel Coombs

School of Mathematical & Statistical Sciences Faculty Publications

Background

Metarhizium anisopliae is a naturally occurring fungal pathogen of mosquitoes. Recently, Metarhizium has been engineered to act against malaria by directly killing the disease agent within mosquito vectors and also effectively blocking onward transmission. It has been proposed that efforts should be made to minimize the virulence of the fungal pathogen, in order to slow the development of resistant mosquitoes following an actual deployment.

Results

Two mathematical models were developed and analysed to examine the efficacy of the fungal pathogen. It was found that, in many plausible scenarios, the best effects are achieved with a reduced or minimal pathogen …

Fluid Dynamic Modeling Of Nano-Thermite Reactions, Karen S. Martirosyan, Maxim Zyskin, Charles M. Jenkins, Yasuyuki Horie

Physics & Astronomy Faculty Publications

This paper presents a direct numerical method based on gas dynamic equations to predict pressure evolution during the discharge of nanoenergetic materials. The direct numerical method provides for modeling reflections of the shock waves from the reactor walls that generates pressure-time fluctuations. The results of gas pressure prediction are consistent with the experimental evidence and estimates based on the self-similar solution. Artificial viscosity provides sufficient smoothing of shock wave discontinuity for the numerical procedure. The direct numerical method is more computationally demanding and flexible than self-similar solution, in particular it allows study of a shock wave in its early stage …

A Study Of Personal Cloud Computing: Compatibility, Social Influence, And Moderating Role Of Perceived Familiarity, Murad Moqbel, Valerie L. Bartelt, Mohammed Al-Suqri

Information Systems Faculty Publications

Building on a research framework based on the Theory of Reasoned Action (TRA), Innovation Diffusion Technology (IDT), and the Technology Adoption Model (TAM), we propose a model integrating compatibility, social influence, and perceived familiarity given the implicit uncertainty of personal cloud. Our model emphasizes the moderating effect of perceived familiarity on the relationships between both perceived compatibility and social influence on behavioral intention. PLS-based structural equation modeling is employed to test the related propositions empirically. Results from a survey, involving 265 university students, reveal that perceived compatibility explains a larger proportion of the variance in behavioral intention; perceived familiarity plays …

Sedimentation And Barnacle Recruitment And Growth In A Shallow Coastal Lagoon Of South Texas, John Jack Gray

Theses and Dissertations - UTB/UTPA

According to the United States Environmental Protection Agency, one of this nation’s greatest concerns to the receiving waters of an aquatic system is the impairment of water quality due to sediment transport. Thus, an aquatic system whose receiving waters are subject to unrestrained sediment transport from a spoil bank, which is an unstabilized depository for sediment acquired during a dredge, should be a concern. In this study an attempt was made to assess sedimentation and its effect on the life cycle of sessile aquatic life over a year. South Bay was chosen for the study site because it is adjacent …