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University of Texas Rio Grande Valley

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Articles 1351 - 1380 of 2419

Full-Text Articles in Physical Sciences and Mathematics

A Comparison Of Salinity Effects From Hurricanes Dolly (2008) And Alex (2010) In A Texas Lagoon System, Joseph L. Kowalski, Hudson R. Deyoe, Gilbert H. Boza Jr., Donald L. Hockaday, Paul V. Zimba May 2018

A Comparison Of Salinity Effects From Hurricanes Dolly (2008) And Alex (2010) In A Texas Lagoon System, Joseph L. Kowalski, Hudson R. Deyoe, Gilbert H. Boza Jr., Donald L. Hockaday, Paul V. Zimba

Biology Faculty Publications and Presentations

A comparison of salinity effects from hurricanes Dolly (2008) and Alex (2010) in a Texas lagoon system.Hurricanes are not uncommon along the Gulf of Mexico coast, but there are few studies of the effects they have on coastal embayments. Hurricanes Dolly (2008) and Alex (2010) were both Category 2 storms affecting the Lower Laguna Madre (LLM) of Texas. Surveys were performed to assess poststorm water quality after landfall of both storms at up to 18 sample stations. The main difference between storm effects was salinity reduction because of stormwater input from the watershed. Effects from Hurricane Dolly were of short …


Search For Tensor Vector And Scalar Polarizations In The Stochastic Gravitational-Wave Background, B. P. Abbott, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, C. Adams, T. Adams, P. Addesso, R. X. Adhikari, V. B. Adya, C. Affeldt, M. Afrough, B. Agarwal, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, P. Ajith, B. Allen, G. Allen, A. Allocca, P. A. Altin, A. Amato, A. Ananyeva, S. B. Anderson, W. G. Anderson, S. V. Angelova, S. Antier May 2018

Search For Tensor Vector And Scalar Polarizations In The Stochastic Gravitational-Wave Background, B. P. Abbott, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, C. Adams, T. Adams, P. Addesso, R. X. Adhikari, V. B. Adya, C. Affeldt, M. Afrough, B. Agarwal, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, P. Ajith, B. Allen, G. Allen, A. Allocca, P. A. Altin, A. Amato, A. Ananyeva, S. B. Anderson, W. G. Anderson, S. V. Angelova, S. Antier

Physics and Astronomy Faculty Publications and Presentations

The detection of gravitational waves with Advanced LIGO and Advanced Virgo has enabled novel tests of general relativity, including direct study of the polarization of gravitational waves. While general relativity allows for only two tensor gravitational-wave polarizations, general metric theories can additionally predict two vector and two scalar polarizations. The polarization of gravitational waves is encoded in the spectral shape of the stochastic gravitational-wave background, formed by the superposition of cosmological and individually unresolved astrophysical sources. Using data recorded by Advanced LIGO during its first observing run, we search for a stochastic background of generically polarized gravitational waves. We find …


Full Band All-Sky Search For Periodic Gravitational Waves In The O1 Ligo Data, C. J. Haster, K. Haughian, J. Healy, A. Heidmann, M. C. Heintze, H. Heitmann, P. Hello, G. Hemming, M. Hendry, I. S. Heng, J. Hennig, A. W. Heptonstall, M. Heurs, S. Hild, T. Hinderer, D. Hoak, D. Hofman, K. Holt, D. E. Holz, P. Hopkins, C. Horst, J. Hough, E. A. Houston, E. J. Howell, A. Hreibi, Y. M. Hu, E. A. Huerta, D. Huet, B. Hughey, S. Husa May 2018

Full Band All-Sky Search For Periodic Gravitational Waves In The O1 Ligo Data, C. J. Haster, K. Haughian, J. Healy, A. Heidmann, M. C. Heintze, H. Heitmann, P. Hello, G. Hemming, M. Hendry, I. S. Heng, J. Hennig, A. W. Heptonstall, M. Heurs, S. Hild, T. Hinderer, D. Hoak, D. Hofman, K. Holt, D. E. Holz, P. Hopkins, C. Horst, J. Hough, E. A. Houston, E. J. Howell, A. Hreibi, Y. M. Hu, E. A. Huerta, D. Huet, B. Hughey, S. Husa

Physics and Astronomy Faculty Publications and Presentations

We report on a new all-sky search for periodic gravitational waves in the frequency band 475-2000 Hz and with a frequency time derivative in the range of [-1.0,+0.1]×10-8 Hz/s. Potential signals could be produced by a nearby spinning and slightly nonaxisymmetric isolated neutron star in our Galaxy. This search uses the data from Advanced LIGO's first observational run O1. No gravitational-wave signals were observed, and upper limits were placed on their strengths. For completeness, results from the separately published low-frequency search 20-475 Hz are included as well. Our lowest upper limit on worst-case (linearly polarized) strain amplitude h0 is ∼4×10-25 …


Constraints On Cosmic Strings Using Data From The First Advanced Ligo Observing Run, B. P. Abbott, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, C. Adams, T. Adams, P. Addesso, R. X. Adhikari, V. B. Adya, C. Affeldt, M. Afrough, B. Agarwal, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, P. Ajith, B. Allen, G. Allen, A. Allocca, P. A. Altin, A. Amato, A. Ananyeva, S. B. Anderson, W. G. Anderson, S. Antier, S. Appert May 2018

Constraints On Cosmic Strings Using Data From The First Advanced Ligo Observing Run, B. P. Abbott, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, C. Adams, T. Adams, P. Addesso, R. X. Adhikari, V. B. Adya, C. Affeldt, M. Afrough, B. Agarwal, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, P. Ajith, B. Allen, G. Allen, A. Allocca, P. A. Altin, A. Amato, A. Ananyeva, S. B. Anderson, W. G. Anderson, S. Antier, S. Appert

Physics and Astronomy Faculty Publications and Presentations

Cosmic strings are topological defects which can be formed in grand unified theory scale phase transitions in the early universe. They are also predicted to form in the context of string theory. The main mechanism for a network of Nambu-Goto cosmic strings to lose energy is through the production of loops and the subsequent emission of gravitational waves, thus offering an experimental signature for the existence of cosmic strings. Here we report on the analysis conducted to specifically search for gravitational-wave bursts from cosmic string loops in the data of Advanced LIGO 2015-2016 observing run (O1). No evidence of such …


Microwave-Assisted Ring-Opening Polymerization Of Poly(Ε-Caprolactone), Nancy Obregon May 2018

Microwave-Assisted Ring-Opening Polymerization Of Poly(Ε-Caprolactone), Nancy Obregon

Theses and Dissertations

Poly(ϵ-caprolactone) (PCL) is a biodegradable polyester notorious by its promising properties and applications in the biomedical field. In this work, microwave-assisted ringopening polymerization (ROP) of ϵ-caprolactone (ϵ-CL) was performed. Stannous octoate [Sn(Oct)2] was used as catalyst with and without an alcohol initiator. The different initiators tested were glycerol, diethylene glycol (DEG) and poly(ethylene) glycol (PEG). Aiming to establish reaction parameters, the influence of different reaction times, temperatures, and monomer:initiator:catalyst ratios were examined. It was observed that the reaction was obtained and high molecular weight PCL was achieved successfully without an initiator. However, mixed results were obtained using an initiator. Products …


Magnetic Polymer Composite As A Thermosensitive Agent For Induced Hyperthermia, Nareg Ohannesian May 2018

Magnetic Polymer Composite As A Thermosensitive Agent For Induced Hyperthermia, Nareg Ohannesian

Theses and Dissertations

Polyetheretherketone (PEEK) - magnetite (Fe3O4) blended compounds were produced by high speed vibration milling of PEEK-Fe 3O4 powders exposed to hexane and heated to the melting point (~350 °C) to form the homogeneous magnetic polymer composite, which provided a uniform dispersion of magnetite with low agglomerations in the polymer matrix. Polymer composite with 10 wt.% of magnetite displayed a magnetic saturation of 8 emu/g, tensile strength of 60 MPa and Young’s modulus of 4.4 GPa. Biotoxicity assessment was conducted via in vitro assay. The composite did not induce any adverse reactions, permitting use in medical applications. This study develops analytical …


Spatial And Temporal Trends In Diet For Pinfish (Lagodon Rhomboides) From Turtle Grass (Thalassia Testudinum) Beds With Contrasting Environmental Regimes In The Lower Laguna Madre, Texas, Maximiliano Barbosa May 2018

Spatial And Temporal Trends In Diet For Pinfish (Lagodon Rhomboides) From Turtle Grass (Thalassia Testudinum) Beds With Contrasting Environmental Regimes In The Lower Laguna Madre, Texas, Maximiliano Barbosa

Theses and Dissertations

Seagrass meadows in far South Texas are dominated by turtle grass (Thalassia testudinum), and juvenile pinfish (Lagodon rhomboides) are abundant grazers of seagrass epifauna. As they grow, pinfish exhibit an ontogenetic dietary shift and begin consuming increasing amounts of plant material. In this study, contrasting environmental regimes in two seagrass meadows were examined to identify how they might affect pinfish diets, diet shifts, and growth across the growing season. The eastern site was sheltered from prevailing southeasterly winds by a barrier island, while the western site was shallower and subjected to higher wind energy and turbidity. …


Extraction Of Metazoan Meiofauna From Muddy Deep-Sea Samples: Operator And Taxon Effects On Efficiency, Melissa Rohal, David Thistle, Erin E. Easton May 2018

Extraction Of Metazoan Meiofauna From Muddy Deep-Sea Samples: Operator And Taxon Effects On Efficiency, Melissa Rohal, David Thistle, Erin E. Easton

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

Deep-sea metazoan meiofaunal specimens are usually extracted from muddy samples by centrifugation in a fluid in which meiofauna tend to float and sediment particles tend to sink. Although the procedure is in common use, its efficiency has seldom been examined. The study reported here showed that well-trained operators extracted metazoan meiofauna with efficiencies that were different enough to be a concern in quantitative studies. Therefore, samples should be assigned to operators in a stratified-random manner. In the course of these studies, both operators also extracted individuals of the common nematode family Desmoscolecidae significantly less efficiently than other nematode families, a …


A Multiple Radar Approach For Automatic Target Recognition Of Aircraft Using Inverse Synthetic Aperture Radar, Carlos Pena-Caballero, Elifaleth Cantu, Jesus Rodriguez, Adolfo Gonzales, Osvaldo Castellanos, Angel Cantu, Megan K. Strait, Jae Son, Dong-Chul Kim May 2018

A Multiple Radar Approach For Automatic Target Recognition Of Aircraft Using Inverse Synthetic Aperture Radar, Carlos Pena-Caballero, Elifaleth Cantu, Jesus Rodriguez, Adolfo Gonzales, Osvaldo Castellanos, Angel Cantu, Megan K. Strait, Jae Son, Dong-Chul Kim

Computer Science Faculty Publications and Presentations

Following the recent advancements in radar technologies, research on automatic target recognition using Inverse Synthetic Aperture Radar (ISAR) has correspondingly seen more attention and activity. ISAR automatic target recognition researchers aim to fully automate recognition and classification of military vehicles, but because radar images often do not present a clear image of what they detect, it is considered a challenging process to do this. Here we present a novel approach to fully automate a system with Convolutional Neural Networks (CNNs) that results in better target recognition and requires less training time. Specifically, we developed a simulator to generate images with …


Simplification Of Eeg Signal Extraction, Processing, And Classification Using A Consumer-Grade Headset To Facilitate Student Engagement In Bci Research, Jesus D. Rodriguez May 2018

Simplification Of Eeg Signal Extraction, Processing, And Classification Using A Consumer-Grade Headset To Facilitate Student Engagement In Bci Research, Jesus D. Rodriguez

Theses and Dissertations

Brain-computer interfaces (BCIs) are an emerging technology that leverage neurophysiological signals as input to computing systems. By circumventing the reliance on traditional input methods (e.g., mouse and keyboard), BCIs show a promising alternative interaction modality for people with disabilities. Advances in BCI research have further inspired a range of novel applications, such as the use of neurophysiological signals as passive input (e.g., to detect and reduce operator workload when managing multiple machines). BCIs have also emerged as a tool for student engagement due to the intrinsic interdisciplinarity of the technology, which spans the fields of computer science, electrical engineering, neuroscience, …


Experimental And Computational Studies Of Rotation And Proton Tunneling In Organic Molecules And Molecular Dimers, Agapito Serrato Iii May 2018

Experimental And Computational Studies Of Rotation And Proton Tunneling In Organic Molecules And Molecular Dimers, Agapito Serrato Iii

Theses and Dissertations

An introduction to the relations of classical and quantum mechanics are presented in brief. As is an overview of the instrumentation and quantum chemical analysis performed to characterize the molecules presented in in this thesis. The pure rotational spectrum of 3,3,3-trifluoro-2(trifluoromethyl)propanoic acid, perfluorobutyric acid–formic acid dimer, and tropolone–formic acid dimer were measured using high-resolution microwave spectroscopy. The spectra have been observed using a cavity-based Fourier-transform microwave (FTMW) spectrometer and/or a chirped-pulse FTMW.


Removal Of Chromium(Vi) And Chromium(Iii) Ions From Aqueous Solution Using Bio-Char Generated From Agricultural Waste Products, Diego Fernando Gonzalez May 2018

Removal Of Chromium(Vi) And Chromium(Iii) Ions From Aqueous Solution Using Bio-Char Generated From Agricultural Waste Products, Diego Fernando Gonzalez

Theses and Dissertations

Heavy metals are one of the most persistent and prevalent contaminants in the aquatic environment. The removal of chromium from aqueous solution, especially in the hexavalent form is difficult. New technologies, techniques and/or new materials have been designed in order to effectively and efficiently remove chromium from the aqueous environment. The project focuses on the comparison of the effects of pH, time, temperature, binding capacity on bio-char’ generated from agricultural waste produces vs an amino modified derivative of the bio-char. Pineapple skins were dried, ground, sieved, and pyrolyzed to produce a bio-char material. The bio-char was analyzed using FTIR to …


Design And Development Of Inquiry-Based Materials For Conducting Observational Astronomy Research At Utrgv, Americo Francisco Hinojosa Lee May 2018

Design And Development Of Inquiry-Based Materials For Conducting Observational Astronomy Research At Utrgv, Americo Francisco Hinojosa Lee

Theses and Dissertations

The purpose of this work is to develop instructional materials to enhance the expertise of students in conducting observational astronomy research. The designed instructional units aim to provide students with an adequate knowledge of astronomy and hone their skills necessary in conducting observations, collecting and analyzing data including processing of astronomical images.

The instructional design is anchored on the ADDIE model (Analyze, Design, Develop, Implement and Evaluate). The phases from ADDIE were used as a framework to accomplish the process of developing the instructional materials. After following the ADDIE, it was possible to define performance goals and tasks which were …


Approximate Set Union Via Approximate Randomization, Pengfei Gu May 2018

Approximate Set Union Via Approximate Randomization, Pengfei Gu

Theses and Dissertations

We develop an randomized approximation algorithm for the size of set union problem |A1 U A2 U...UAm|, which given a list of sets A1,...,Am with approximate set size m i for Ai with mi ∈ ((1–βL)|A i|,(1+βR)|Ai|), and biased random generators with Prob(x = RandomElement(Ai)) ∈ [1–a L/Ai, 1 +aR/Ai] for each input set Ai and element x ∈ Ai, where i = 1,2,...,m. The approximation |Ai | |Ai | ratio for |A1 U A2 U...UAm| is in the range [(1–ϵ)(1–aL)(1–βL),(1+ϵ)(1+β R)(1+βR)] for any ϵ ∈ (0,1), where α L,αR,βL,βR ∈ (0,1). The complexity of the algorithm …


Carbon Nanotube Yarn Based Dye Sensitized Solar Cells With Enhanced Electron/Hole Pair Recombination Prevention Characteristics, Glenn E. Grissom May 2018

Carbon Nanotube Yarn Based Dye Sensitized Solar Cells With Enhanced Electron/Hole Pair Recombination Prevention Characteristics, Glenn E. Grissom

Theses and Dissertations

Carbon nanotube yarn based solar cells (CNTYSCs) show promise in a variety of applications such as military and smart fabrics. We use a highly aligned and interwoven Carbon nanotube yarn (CNTY) for the working electrode (WE) and counter electrode (CE), to create a flexible super strong, conductive, and photo active surface for the support of a calcined TiO2 nano-solution and macro-solution deposition as a base for added functionalizations of a dye-sensitized solar cell (DSSC) that is able to maintain its flexibility and integrity. The CNT fiber based solar cells have power conversion ability that is independent of the direction of …


Covering A Ball By Smaller Balls, Alexey Glazyrin May 2018

Covering A Ball By Smaller Balls, Alexey Glazyrin

School of Mathematical and Statistical Sciences Faculty Publications and Presentations

We prove that, for any covering of a unit d-dimensional Euclidean ball by smaller balls, the sum of radii of the balls from the covering is greater than d. We also investigate the problem of finding lower and upper bounds for the sum of powers of radii of the balls covering a unit ball.


The Local Theory For Regular Systems In The Context Of T-Bonded Sets, Mikhail M. Bouniaev, Nikolay Dolbilin May 2018

The Local Theory For Regular Systems In The Context Of T-Bonded Sets, Mikhail M. Bouniaev, Nikolay Dolbilin

School of Mathematical and Statistical Sciences Faculty Publications and Presentations

The main goal of the local theory for crystals developed in the last quarter of the 20th Century by a geometry group of Delone (Delaunay) at the Steklov Mathematical Institute is to find and prove the correct statements rigorously explaining why the crystalline structure follows from the pair-wise identity of local arrangements around each atom. Originally, the local theory for regular and multiregular systems was developed with the assumption that all point sets under consideration are (r,R)" role="presentation">(r,R) -systems or, in other words, Delone sets of type (r,R)" role="presentation">(r,R) in d-dimensional Euclidean space. In this paper, we will …


Who Will Stay, Who Will Leave: Decision-Making Of Residents Living In Potential Hurricane Impact Areas During A Hypothetical Hurricane Event In The Rio Grande Valley, Dean Kyne, Arlett Sophia Lomeli, William Donner, Erika Zuloaga Apr 2018

Who Will Stay, Who Will Leave: Decision-Making Of Residents Living In Potential Hurricane Impact Areas During A Hypothetical Hurricane Event In The Rio Grande Valley, Dean Kyne, Arlett Sophia Lomeli, William Donner, Erika Zuloaga

Sociology Faculty Publications and Presentations

The Rio Grande Valley (RGV) has been impacted by various hurricanes throughout history. While Hurricane evacuation has been studied extensively in other contexts, there is limited systematic research on the warning and response to a large-scale severe weather event in South Texas. This study attempts to understand the evacuation decision-making behavior of Southern residents in the event of a Hurricane making landfall over the Rio Grande Valley. The study uses an online survey questionnaire with 1060 participants: 275 students attending the University of Texas-Rio Grande Valley and the remaining 785 are members of the community. Throughout the course of the …


Using Restrictions To Accept Or Reject Solutions Of Radical Equations, Eleftherios Gkioulekas Apr 2018

Using Restrictions To Accept Or Reject Solutions Of Radical Equations, Eleftherios Gkioulekas

School of Mathematical and Statistical Sciences Faculty Publications and Presentations

The standard technique for solving equations with radicals is to square both sides of the equation as many times as necessary to eliminate all radicals. Because the procedure violates logical equivalence, it results in extraneous solutions that do not satisfy the original equation, making it necessary to check all solutions against the original equation. We propose alternative solution procedures that are rigorous and simple to execute where the extraneous solutions can be identified without verification against the original equation. In this article, we review previous literature, establish and illustrate rigorous solution procedures for radical equations of depth 1 (i.e. equations …


Mesoscale Effects On Carbon Export: A Global Perspective, Cheryl S. Harrison, Matthew C. Long, Nicole S. Lovenduski, Jefferson K. Moore Apr 2018

Mesoscale Effects On Carbon Export: A Global Perspective, Cheryl S. Harrison, Matthew C. Long, Nicole S. Lovenduski, Jefferson K. Moore

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

Carbon export from the surface to the deep ocean is a primary control on global carbon budgets and is mediated by plankton that are sensitive to physical forcing. Earth system models generally do not resolve ocean mesoscale circulation ((10–100) km), scales that strongly affect transport of nutrients and plankton. The role of mesoscale circulation in modulating export is evaluated by comparing global ocean simulations conducted at 1∘ and 0.1∘ horizontal resolution. Mesoscale resolution produces a small reduction in globally integrated export production (<2%); however, the impact on local export production can be large (±50%), with compensating effects in different ocean basins. With mesoscale resolution, improved representation of coastal jets block off-shelf transport, leading to lower export in regions where shelf-derived nutrients fuel production. Export is further reduced in these regions by resolution of mesoscale turbulence, which restricts the spatial area of production. Maximum mixed layer depths are narrower and deeper across the Subantarctic at higher resolution, driving locally stronger nutrient entrainment and enhanced summer export production. In energetic regions with seasonal blooms, such as the Subantarctic and North Pacific, internally generated mesoscale variability drives substantial interannual variation in local export production. These results suggest that biogeochemical tracer dynamics show different sensitivities to transport biases than temperature and salinity, which should be considered in the formulation and validation of physical parameterizations. Efforts to compare estimates of export production from observations and models should account for large variability in space and time expected for regions strongly affected by mesoscale circulation.


Microwave-Induced Bismuth Nitrate-Impregnated Claymediated Novel Dinitration Of 9,10- Dihydrophenanthrene: A Precursor For New Heterocycles, Ram Naresh Yadav, Leonardo Salazar, Amrendra Kumar Singh, Bimal K. Banik Apr 2018

Microwave-Induced Bismuth Nitrate-Impregnated Claymediated Novel Dinitration Of 9,10- Dihydrophenanthrene: A Precursor For New Heterocycles, Ram Naresh Yadav, Leonardo Salazar, Amrendra Kumar Singh, Bimal K. Banik

Chemistry Faculty Publications and Presentations

A facile method for the dinitration of 9, 10-dihydrophenanthrene using domestic microwave-induced bismuth nitrate-impregnated clay is developed.


The Nanograv 11-Year Data Set: High-Precision Timing Of 45 Millisecond Pulsars, Z. Arzoumanian, Adam Brazier, Sarah Burke-Spolaor, Sydney Chamberlin, Shami Chatterjee, Brian Christy, James M. Cordes, Neil J. Cornish, Fronefield Crawford, H. Thankful Cromartie, Kathryn Crowter, Megan E. Decesar, Paul B. Demorest, Timothy Dolch, Justin A. Ellis, Robert D. Ferdman, Elizabeth C. Ferrara, Emmanuel Fonseca, Nathan Garver-Daniels, Peter A. Gentile, Daniel Halmrast, E. A. Huerta, Fredrick A. Jenet, Cody Jessup, Glenn Jones, Megan L. Jones, David L. Kaplan, Michael T. Lam, T. Joseph W. Lazio, Lina Levin Apr 2018

The Nanograv 11-Year Data Set: High-Precision Timing Of 45 Millisecond Pulsars, Z. Arzoumanian, Adam Brazier, Sarah Burke-Spolaor, Sydney Chamberlin, Shami Chatterjee, Brian Christy, James M. Cordes, Neil J. Cornish, Fronefield Crawford, H. Thankful Cromartie, Kathryn Crowter, Megan E. Decesar, Paul B. Demorest, Timothy Dolch, Justin A. Ellis, Robert D. Ferdman, Elizabeth C. Ferrara, Emmanuel Fonseca, Nathan Garver-Daniels, Peter A. Gentile, Daniel Halmrast, E. A. Huerta, Fredrick A. Jenet, Cody Jessup, Glenn Jones, Megan L. Jones, David L. Kaplan, Michael T. Lam, T. Joseph W. Lazio, Lina Levin

Physics and Astronomy Faculty Publications and Presentations

We present high-precision timing data over time spans of up to 11 years for 45 millisecond pulsars observed as part of the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) project, aimed at detecting and characterizing low-frequency gravitational waves. The pulsars were observed with the Arecibo Observatory and/or the Green Bank Telescope at frequencies ranging from 327 MHz to 2.3 GHz. Most pulsars were observed with approximately monthly cadence, and six high-timing-precision pulsars were observed weekly. All were observed at widely separated frequencies at each observing epoch in order to fit for time-variable dispersion delays. We describe our methods for …


Optimal Quantizers For Some Absolutely Continuous Probability Measures, Mrinal Kanti Roychowdhury Apr 2018

Optimal Quantizers For Some Absolutely Continuous Probability Measures, Mrinal Kanti Roychowdhury

School of Mathematical and Statistical Sciences Faculty Publications and Presentations

The representation of a given quantity with less information is often referred to as `quantization' and it is an important subject in information theory. In this paper, we have considered absolutely continuous probability measures on unit discs, squares, and the real line. For these probability measures the optimal sets of n-means and the nth quantization errors are calculated for some positive integers n.


A Model For Donation Verification, Bin Fu, Fengjuan Zhu, John P. Abraham Mar 2018

A Model For Donation Verification, Bin Fu, Fengjuan Zhu, John P. Abraham

Computer Science Faculty Publications and Presentations

In this paper, we introduce a model for donation verification. A randomized algorithm is developed to check if the money claimed being received by the collector is (1 - ϵ)-approximation to the total amount money contributed by the donors. We also derive some negative results that show it is impossible to verify the donations under some circumstances.


Anomalous Electromagnetic Transport In Compact Stars, Efrain J. Ferrer, Vivian De La Incera Mar 2018

Anomalous Electromagnetic Transport In Compact Stars, Efrain J. Ferrer, Vivian De La Incera

Physics and Astronomy Faculty Publications and Presentations

We study the anomalous electromagnetic transport properties of a quark-matter phase that can be realized in the presence of a magnetic field in the low-temperature/moderate-high-density region of the Quantum Chromodynamics (QCD) phase map. In this so-called Magnetic Dual Chiral Density Wave phase, an inhomogeneous condensate is dynamically induced producing a nontrivial topology, a consequence of the asymmetry of the lowest Landau level modes of the quasiparticles in this phase. The nontrivial topology manifests in the electromagnetic effective action via a chiral anomaly term 𝜃𝐹𝜇𝜈𝐹˜𝜇𝜈 , with an axion field 𝜃 given by the phase of the Dual Chiral Density Wave …


Discovery And Characterization Of Chemical Compounds That Inhibit The Function Of Aspartyl-Trna Synthetase From Pseudomonas Aeruginosa, Araceli Corona, Stephanie O. Palmer, Regina Zamacona, Benjamin Mendez, Frank B. Dean, James M. Bullard Mar 2018

Discovery And Characterization Of Chemical Compounds That Inhibit The Function Of Aspartyl-Trna Synthetase From Pseudomonas Aeruginosa, Araceli Corona, Stephanie O. Palmer, Regina Zamacona, Benjamin Mendez, Frank B. Dean, James M. Bullard

Chemistry Faculty Publications and Presentations

Pseudomonas aeruginosa, an opportunistic pathogen, is highly susceptible to developing resistance to multiple antibiotics. The gene encoding aspartyl-tRNA synthetase (AspRS) from P. aeruginosa was cloned and the resulting protein characterized. AspRS was kinetically evaluated, and the KM values for aspartic acid, ATP, and tRNA were 170, 495, and 0.5 μM, respectively. AspRS was developed into a screening platform using scintillation proximity assay (SPA) technology and used to screen 1690 chemical compounds, resulting in the identification of two inhibitory compounds, BT02A02 and BT02C05. The minimum inhibitory concentrations (MICs) were determined against nine clinically relevant bacterial strains, including efflux pump …


Gw170817: Implications For The Stochastic Gravitational-Wave Background From Compact Binary Coalescences, B. P. Abbott, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, C. Adams, T. Adams, P. Addesso, R. X. Adhikari, V. B. Adya, C. Affeldt, M. Afrough, B. Agarwal, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, P. Ajith, B. Allen, G. Allen, A. Allocca, P. A. Altin, A. Amato, A. Ananyeva, S. B. Anderson, W. G. Anderson, S. V. Angelova, S. Antier Feb 2018

Gw170817: Implications For The Stochastic Gravitational-Wave Background From Compact Binary Coalescences, B. P. Abbott, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, C. Adams, T. Adams, P. Addesso, R. X. Adhikari, V. B. Adya, C. Affeldt, M. Afrough, B. Agarwal, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, P. Ajith, B. Allen, G. Allen, A. Allocca, P. A. Altin, A. Amato, A. Ananyeva, S. B. Anderson, W. G. Anderson, S. V. Angelova, S. Antier

Physics and Astronomy Faculty Publications and Presentations

The LIGO Scientific and Virgo Collaborations have announced the event GW170817, the first detection of gravitational waves from the coalescence of two neutron stars. The merger rate of binary neutron stars estimated from this event suggests that distant, unresolvable binary neutron stars create a significant astrophysical stochastic gravitational-wave background. The binary neutron star component will add to the contribution from binary black holes, increasing the amplitude of the total astrophysical background relative to previous expectations. In the Advanced LIGO-Virgo frequency band most sensitive to stochastic backgrounds (near 25 Hz), we predict a total astrophysical background with amplitude ΩGW(f=25 Hz)=1.8-1.3+2.7×10-9 with …


Effects Of Herbivores, Wave Exposure And Depth On Benthic Coral Communities Of The Easter Island Ecoregion, Erin E. Easton, Carlos F. Gaymer, Alan M. Friedlander, James J. Herlan Feb 2018

Effects Of Herbivores, Wave Exposure And Depth On Benthic Coral Communities Of The Easter Island Ecoregion, Erin E. Easton, Carlos F. Gaymer, Alan M. Friedlander, James J. Herlan

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

The Easter Island ecoregion includes Rapa Nui (Easter Island; RN), with a human population of ~5600, and the uninhabited Salas y Gómez (SyG). Although the culture and terrestrial ecology of RN have been well studied, we know little about the marine environment of these islands, particularly the interplay among herbivores, algae, and corals, and how coral reef communities differ between islands, by wave energy exposure, and between depths. To address the potential roles of herbivores, wave-energy exposure, and depth on the sessile benthic communities, we examined herbivorous fish biomass, sea urchin (Diadema savignyi) density, and algal and coral …


Palfa Discovery Of A Highly Relativistic Double Neutron Star Binary, K. Stovall, P. C.C. Freire, S. Chatterjee, P. B. Demorest, D. R. Lorimer, M. A. Mclaughlin, N. Pol, J. Van Leeuwen, R. S. Wharton, B. Allen, M. Boyce, A. Brazier, K. Caballero, F. Camilo, R. Camuccio, J. M. Cordes, F. Crawford, J. S. Deneva, R. D. Ferdman, J. W.T. Hessels, F. A. Jenet, V. M. Kaspi, B. Knispel, P. Lazarus, R. Lynch, E. Parent, C. Patel, Z. Pleunis, S. M. Ransom, P. Scholz Feb 2018

Palfa Discovery Of A Highly Relativistic Double Neutron Star Binary, K. Stovall, P. C.C. Freire, S. Chatterjee, P. B. Demorest, D. R. Lorimer, M. A. Mclaughlin, N. Pol, J. Van Leeuwen, R. S. Wharton, B. Allen, M. Boyce, A. Brazier, K. Caballero, F. Camilo, R. Camuccio, J. M. Cordes, F. Crawford, J. S. Deneva, R. D. Ferdman, J. W.T. Hessels, F. A. Jenet, V. M. Kaspi, B. Knispel, P. Lazarus, R. Lynch, E. Parent, C. Patel, Z. Pleunis, S. M. Ransom, P. Scholz

Physics and Astronomy Faculty Publications and Presentations

We report the discovery and initial follow-up of a double neutron star (DNS) system, PSR J1946+2052, with the Arecibo L-Band Feed Array pulsar (PALFA) survey. PSR J1946+2052 is a 17 ms pulsar in a 1.88 hr, eccentric (e = 0.06) orbit with a 1.2 M o companion. We have used the Jansky Very Large Array to localize PSR J1946+2052 to a precision of 0.″09 using a new phase binning mode. We have searched multiwavelength catalogs for coincident sources but did not find any counterparts. The improved position enabled a measurement of the spin period derivative of the pulsar (P = …


Cartan Frames And Algebras With Links To Integrable Systems Differential Equations And Surfaces, Paul Bracken Feb 2018

Cartan Frames And Algebras With Links To Integrable Systems Differential Equations And Surfaces, Paul Bracken

School of Mathematical and Statistical Sciences Faculty Publications and Presentations

Moving frames and Clifford algebras will be used to illustrate an interconnected approach to the study of integrable systems, their surfaces, and methods for producing integrable partial differential equations. After a system of one-forms is defined, moving frame equations can be integrated and the resulting equations for the surface can be obtained. Other differential equations which involve quantities relevant to the surface are obtained. For the case of minimal and constant mean curvature surfaces, the coordinate functions can be calculated in closed form. In the case of constant mean curvature, they can be expressed in terms of Jacobi elliptic functions.