Digital Commons Network^™

Improved Upper Limits On The Stochastic Gravitational-Wave Background From 2009–2010 Ligo And Virgo Data, J. Aasi, B. P. Abbott, H. Daveloza, Mario C. Diaz, S. R. Morriss, Soma Mukherjee, M. E. Normandin, O. Puncken, Volker Quetschke, Malik Rakhmanov, Karla E. Ramirez, Joseph D. Romano, Robert Stone

Physics & Astronomy Faculty Publications

Gravitational waves from a variety of sources are predicted to superpose to create a stochastic background. This background is expected to contain unique information from throughout the history of the Universe that is unavailable through standard electromagnetic observations, making its study of fundamental importance to understanding the evolution of the Universe. We carry out a search for the stochastic background with the latest data from the LIGO and Virgo detectors. Consistent with predictions from most stochastic gravitational-wave background models, the data display no evidence of a stochastic gravitational-wave signal. Assuming a gravitational-wave spectrum of ΩGWðfÞ ¼ Ωαðf=fref Þα, we place …

The Collegian (2014-11-17), Cleiri Quezada

UTB/TSC Archives - The Collegian [Newspaper]

Vol. 67, No. 13

Multimessenger Search For Sources Of Gravitational Waves And High-Energy Neutrinos: Initial Results For Ligo-Virgo And Icecube, M. G. Aartsen, M. Ackermann, J. Adams, J. A. Aguilar, M. Ahlers, M. Ahrens, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov

Physics & Astronomy Faculty Publications

We report the results of a multimessenger search for coincident signals from the LIGO and Virgo gravitational-wave observatories and the partially completed IceCube high-energy neutrino detector, including periods of joint operation between 2007-2010. These include parts of the 2005-2007 run and the 2009-2010 run for LIGO-Virgo, and IceCube's observation periods with 22, 59 and 79 strings. We find no significant coincident events, and use the search results to derive upper limits on the rate of joint sources for a range of source emission parameters. For the optimistic assumption of gravitational-wave emission energy of 10-2M c2 at ∼150Hz with ∼60ms duration, …

The Collegian (2014-11-10), Cleiri Quezada

UTB/TSC Archives - The Collegian [Newspaper]

Vol. 67, No. 12

The Pan American (2014-11-06), Susan Gonzalez, Andrew Vera

UTPA Archives - The Pan American Newspaper

Vol. 71, No. 11

The Collegian (2014-11-03), Cleiri Quezada

UTB/TSC Archives - The Collegian [Newspaper]

Vol. 67, No. 11

Limit Distributions Of Random Walks On Stochastic Matrices, Santanu Chakraborty, Arunava Mukherjea

School of Mathematical & Statistical Sciences Faculty Publications

Problems similar to Ann. Prob. 22 (1994) 424–430 and J. Appl. Prob. 23 (1986) 1019–1024 are considered here. The limit distribution of the sequence XnXn−1 ··· X1, where (Xn)n≥1 is a sequence of i.i.d. 2 × 2 stochastic matrices with each Xn distributed as μ, is identified here in a number of discrete situations. A general method is presented and it covers the cases when the random components Cn and Dn (not necessarily independent), (Cn, Dn) being the first column of Xn, have the same (or different) Bernoulli distributions. Thus (Cn, Dn) is valued in {0, r}2, where r is …

Resaca Ecosystem Development: Colonization And Succession Of The Macroinvertebrate Community, Leah M. Mcintosh

Theses and Dissertations - UTB/UTPA

Freshwater wetlands in the Lower Rio Grande Valley of Texas are locally known as resacas. Resacas are remnants of the Rio Grande River channel that were cut off by sedimentation and erosion of river banks. Many are maintained as permanent wetlands through intermittent water pumping from the river; and provide valuable habitat for fish, invertebrates, migratory birds and a diverse floral community in the semi-arid environment of South Texas. Three resacas in different stages of ecosystem development were studied, including one from day zero after re-flooding. The objectives were to document the colonization process of the re-flooded resaca and the …

Pulsar J0453+1559, The 10th Double Neutron Star System In The Universe, Jose Guadalupe Martinez

Theses and Dissertations - UTB/UTPA

Pulsars are neutron stars that spin rapidly, are highly magnetized, and they emit beams of electromagnetic radiation like a lighthouse out in space. These beams of radiation are only observed when the beams face towards Earth and can be measured by a radio telescope. Pulsar studies have an abundance of scientific implementations in solid state physics, general relativity, galactic astronomy, astronomy, planetary physics and have even opened windows in cosmology. This thesis reports the results of a study of pulsar (PSR) J0453+1559, a new binary pulsar discovered in the Arecibo All-Sky 327 MegaHertz Drift Pulsar Survey. The recorded observations of …

A Comparison Of Fish Communities Over Different Reef Configurations In The Northwestern Gulf Of Mexico, Catheline Y. M. Froehlich

Theses and Dissertations - UTB/UTPA

High fishing pressure and limited natural habitat characterize the otherwise barren northwestern Gulf of Mexico. South Texas lacks extensive research of local natural and artificial reefs, and few studies report fish community and sportfish analysis of different reef densities. To alleviate this lack of data, fish abundances were monitored at different reef configurations in the PS-1047 Reef, 13 km off Port Mansfield, Texas, where 4000 concrete culverts were placed in 2011. Four culvert categories (CC1: 1-30 culverts, CC2: 31-70 culverts, CC3: 71-120 culverts, and CC4: 121-190 culverts in a 30-m radius), natural reefs and bare areas were sampled. Species abundances …

Study Of As(Iii) And As(V) Oxoanion Adsorption Onto Single And Mixed Ferrite And Hausmannite Nanomaterials, Sandra Garcia, Saima Sardar, Stephanie Maldonado, Velia Garcia, C Tamez, Jason Parsons

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

The removal of arsenic(III) and arsenic(V) from an aqueous solution through adsorption on to Fe3O4, MnFe2O4, 50% Mn substituted Fe3O4, 75% Mn substituted Fe3O4, and Mn3O4 nanomaterials was investigated. Characterization of the nanomaterials using XRD showed only pure phases for Mn3O4, MnFe2O4, and Fe3O4. The 50% and 75% substituted nanomaterials were found to be mixtures of Mn3O4 and Fe3O4. From batch studies the optimum binding pH of arsenic(III) and arsenic(V) to the nanomaterials was determined to be pH 3. The binding capacity for As(III) and As(VI) to the various nanomaterials was determined using Isotherm studies. The binding capacity of Fe3O4 …

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 …

The Collegian (2014-10-27), Cleiri Quezada

UTB/TSC Archives - The Collegian [Newspaper]

Vol. 67, No. 10

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.

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 …

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 …

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 …

The Collegian (2014-10-06), Cleiri Quezada

UTB/TSC Archives - The Collegian [Newspaper]

Vol. 67, No. 7

Orange & White - Summer/Fall 2014, University Of Texas At Brownsville

UTB/TSC Archives - Orange & White Magazine

No abstract provided.

Utpa Stats At A Glance - Fall 2014, University Of Texas-Pan American

UTPA Archives - Stats At A Glance

No abstract provided.

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

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 …

Recruitment Patterns Of Juvenile Fish At An Artificial Reef In The Gulf Of Mexico, Rachel Noel Arney

Theses and Dissertations - UTB/UTPA

In 2011, the Texas Parks and Wildlife Department deployed 4,000 culverts as an artificial reef off Port Mansfield, TX to serve as habitat for sport fish species in the Gulf of Mexico. The aim of this study was to assess juvenile fish recruitment at particular culvert densities among the reef. Standard monitoring units for the recruitment of reef fish (SMURFs) were used in this study and acted as sampling devices. SMURFs were placed at thirteen sampling stations among four different reef patch densities and sampled repeatedly from 2013-2014. Culvert densities included stations with: zero culverts, 1-50 culverts, 51-100 culverts, and …

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 …

The Collegian (2014-09-29), Cleiri Quezada

UTB/TSC Archives - The Collegian [Newspaper]

Vol. 67, No. 6

The Collegian (2014-09-22), Cleiri Quezada

UTB/TSC Archives - The Collegian [Newspaper]

Vol. 67, No. 5

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 …