Digital Commons Network^™

On The Disk Wind Mass Loss Rates In Qsos, Nicolas A. Pereyra

Physics & Astronomy Faculty Publications

We derive here a relatively simple expression for the total wind mass loss rates in QSOs within the accretion disk wind scenario. We show that the simple expression derived here for QSO disk wind mass loss rate is in a very good agreement with the more “exact” values obtained through significantly more complex and detailed numerically intensive 2.5D time-dependent simulations. Additionally we show that for typical QSO parameters, the disk itself will be emitting mostly in the UV/optical spectrum, in turn implying that the X-ray emission from QSOs likely is produced through some physical mechanism acting at radii smaller than …

The Nanograv Nine-Year Data Set: Observations Arrival Time Measurements And Analysis Of 37 Millisecond Pulsars, Z. Arzoumanian, Zaven Arzoumanian, Adam Brazier, Sarah Burke-Spolaor, Sydney Chamberlin, Shami Chatterjee, Brian Christy, James M. Cordes, Neil Cornish, Fredrick A. Jenet, Jing Luo

Physics & Astronomy Faculty Publications

We present high-precision timing observations spanning up to nine years for 37 millisecond pulsars monitored with the Green Bank and Arecibo radio telescopes as part of the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) project. We describe the observational and instrumental setups used to collect the data, and methodology applied for calculating pulse times of arrival; these include novel methods for measuring instrumental offsets and characterizing low signal-to-noise ratio timing results. The time of arrival data are fit to a physical timing model for each source, including terms that characterize time-variable dispersion measure and frequency-dependent pulse shape evolution. In …

Searches For Continuous Gravitational Waves From Nine Young Supernova Remnants, J. Aasi, B. P. Abbott, R. Abbott, Matthew Benacquista, Teviet Creighton, Mario C. Diaz, Soumya Mohanty, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov

Physics & Astronomy Faculty Publications

We describe directed searches for continuous gravitational waves (GWs) in data from the sixth Laser Interferometer Gravitational-wave Observatory (LIGO) science data run. The targets were nine young supernova remnants not associated with pulsars; eight of the remnants are associated with non-pulsing suspected neutron stars. One target's parameters are uncertain enough to warrant two searches, for a total of 10. Each search covered a broad band of frequencies and first and second frequency derivatives for a fixed sky direction. The searches coherently integrated data from the two LIGO interferometers over time spans from 5.3-25.3 days using the matched-filtering -statistic. We found …

On The Formation And Evolution Of The First Be Star In A Black Hole Binary Mwc 656, M. Grudzinska, K. Belczynski, J. Casares, S. E. De Mink, J. Ziolkowski, I. Negueruela, M. Ribó, I. Ribas, J. M. Paredes, A. Herrero, M. Benacquista

Physics & Astronomy Faculty Publications

We find that the formation of MWC 656 (the first Be binary containing a black hole) involves a common envelope phase and a supernova explosion. This result supports the idea that a rapidly rotating Be star can emerge out of a common envelope phase, which is very intriguing because this evolutionary stage is thought to be too fast to lead to significant accretion and spin up of the B star.We predict ~10-100 of B-BH binaries to currently reside in the Galactic disc, among which around 1/3 contain a Be star, but there is only a small chance to observe a …

The Rider (2015-10-26), Jesus Sanchez

The Rider Archives

Vol.1 No.9

Pulsar J0453+1559: A Double Neutron Star System With A Large Mass Asymmetry, J. G. Martinez, K. Stovall, P. C.C. Freire, J. S. Deneva, F. A. Jenet, M. A. Mclaughlin, M. Bagchi, S. D. Bates, A. Ridolfi

Physics & Astronomy Faculty Publications

To understand the nature of supernovae and neutron star (NS) formation, as well as binary stellar evolution and their interactions, it is important to probe the distribution of NS masses. Until now, all double NS (DNS) systems have been measured as having a mass ratio close to unity (q ≥ 0.91). Here, we report the measurement of the individual masses of the 4.07-day binary pulsar J0453+1559 from measurements of the rate of advance of periastron and Shapiro delay: the mass of the pulsar is Mp = 1.559 � 0.005 Mo and that of its companion is Mo; q = 0.75. …

The Rider (2015-10-12), Jesus Sanchez

The Rider Archives

Vol.1 No.7

Arecibo Pulsar Survey Using Alfa. Iv. Mock Spectrometer Data Analysis, Survey Sensitivity, And The Discovery Of 40 Pulsars, P. Lazarus, A. Brazier, J. W.T. Hessels, C. Karako-Argaman, V. M. Kaspi, R. Lynch, E. Madsen, C. Patel, S. M. Ransom, Fredrick Jenet

Physics & Astronomy Faculty Publications

The on-going Arecibo Pulsar-ALFA (PALFA) survey began in 2004 and is searching for radio pulsars in the Galactic plane at 1.4 GHz. Here we present a comprehensive description of one of its main data reduction pipelines that is based on the PRESTO software and includes new interference-excision algorithms and candidate selection heuristics. This pipeline has been used to discover 40 pulsars, bringing the surveys discovery total to 144 pulsars. Of the new discoveries, eight are millisecond pulsars (MSPs; P 10 ms) and one is a Fast Radio Burst (FRB). This pipeline has also re-detected 188 previously known pulsars, 60 of …

The Rider (2015-10-05), Jesus Sanchez

The Rider Archives

Vol.1 No.6

Utrgv Commencement – Fall 2015, The University Of Texas Rio Grande Valley

UTRGV Commencement Programs

No abstract provided.

Depression, Obesity, And Metabolic Syndrome: Prevalence And Risks Of Comorbidity In A Population-Based Study Of Mexican Americans, Rene L. Olvera, Douglas E. Williamson, Susan P. Fisher-Hoch, Kristina Vatcheva, Joseph B. Mccormick

School of Mathematical & Statistical Sciences Faculty Publications

Introduction: We examined the prevalence of depression, obesity, and metabolic syndrome and associations between them in a population-based representative cohort of Mexican Americans living on the United States-Mexico border.

Method: The sample in this cross-sectional analysis consisted of 1,768 Mexican American adults (≥ 18 years of age) assessed between the years 2004 and 2010, with whom we tested our central hypothesis of a significant relationship between obesity and depression. Depression was measured using the Center for Epidemiologic Studies-Depression scale (CES-D) with a cutoff score of ≥ 16 for depression and a cutoff score of ≥ 27 for severe depression. We …

Using Fish Population Metrics To Compare The Effects Of Artificial Reef Density, Catheline Y. M. Froehlich, Richard Kline

School of Earth, Environmental, & Marine Sciences Faculty Publications

Artificial reefs continue to be added as habitat throughout the world, yet questions remain about how reef design affects fish diversity and abundance. In the present study, the effects of reef density were assessed for fish communities and sizes of economically valuable Lutjanus campechanus 13 km off Port Mansfield, Texas, at a reef composed of more than 4000 concrete culverts. The study spanned from May to June in 2013 and 2014, and sites sampled included natural reefs, bare areas, and varying culvert patch density categories, ranging from 1–190 culverts. Abundances of adults and species evenness of juvenile populations differed between …

Depth-Resolved Multispectral Sub-Surface Imaging Using Multifunctional Upconversion Phosphors With Paramagnetic Properties, Zaven Ovanesyan, L. Christopher Mimun, Gangadharan Ajith Kumar, Brian G. Yust, Chamath Dannongoda, Karen S. Martirosyan, Dhiraj K. Sardar

Physics & Astronomy Faculty Publications

Molecular imaging is very promising technique used for surgical guidance, which requires advancements related to properties of imaging agents and subsequent data retrieval methods from measured multispectral images. In this article, an upconversion material is introduced for subsurface near-infrared imaging and for the depth recovery of the material embedded below the biological tissue. The results confirm significant correlation between the analytical depth estimate of the material under the tissue and the measured ratio of emitted light from the material at two different wavelengths. Experiments with biological tissue samples demonstrate depth resolved imaging using the rare earth doped multifunctional phosphors. In …

Microwave Spectra And Structure Of The Cyclopropanecarboxylic Acid-Formic Acid Dimer, Aaron M. Pejlovas, Wei Lin, Stephen G. Kukolich

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

The rotational spectrum of the cyclopropanecarboxylic acid-formic acid doubly hydrogen bonded dimer has been measured in the 4-11 GHz region using a Flygare-Balle type pulsed-beam Fourier transform microwave spectrometer. Rotational transitions were measured for the parent, four unique singly substituted ¹³C isotopologues, and a singly deuterated isotopologue. Splittings due to a possible concerted double proton tunneling motion were not observed. Rotational constants (A, B, and C) and centrifugal distortion constants (DJ and DJK) were determined from the measured transitions for the dimer. The values of the rotational (in MHz) and centrifugal distortion constants (in kHz) for the parent isotopologue …

The Impact Of Pictorial Representations In Teaching Math Word Problems To A Child With Autism, Hossein Shirvani

Teaching and Learning Faculty Publications

The study used a single subject A-B-A research design because it used one subject, an 18-year old boy participant who was diagnosed with having higher spectrum Autism (Asperger). The investigator examined the effect of pictorial representations of math word problems on the participant’s performance in solving one step, two steps, and three steps math word problems. The investigator found that the use pictorial representations improved the participant’s math achievement in solving math word problems. The investigator also found that the participant had difficulty understanding words with mathematical connotations.

Nanograv Constraints On Gravitational Wave Bursts With Memory, Z. Arzoumanian, A. Brazier, S. Burke-Spolaor, S. J. Chamberlin, S. Chatterjee, B. Christy, J. M. Cordes, N. J. Cornish, Fredrick A. Jenet, Jing Luo

Physics & Astronomy Faculty Publications

Among efforts to detect gravitational radiation, pulsar timing arrays are uniquely poised to detect \"memory\" signatures, permanent perturbations in spacetime from highly energetic astrophysical events such as mergers of supermassive black hole binaries. The North American Nanohertz Observatory for Gravitational Waves (NANOGrav) observes dozens of the most stable millisecond pulsars using the Arecibo and Green Bank radio telescopes in an effort to study, among other things, gravitational wave memory. We herein present the results of a search for gravitational wave bursts with memory (BWMs) using the first five years of NANOGrav observations. We develop original methods for dramatically speeding up …

Barriers To Disaster Preparedness Among Medical Special Needs Populations, Leslie Meyer, Kristina Vatcheva, Stephanie Castellanos, Belinda M. Reininger

School of Mathematical & Statistical Sciences Faculty Publications

A medical special needs (MSN) assessment was conducted among 3088 respondents in a hurricane prone area. The sample was female (51.7%), Hispanic (92.9%), aged >45 years (51%), not insured for health (59.2%), and with an MSN (33.2%). Barriers to preparedness were characterized for all households, including those with inhabitants reporting MSN ranging from level 0 (mild) to level 4 (most severe). Multivariable logistic regression tested associations between hurricane preparedness and barriers to evacuation by level of MSN. A significant interaction effect between number of evacuation barriers and MSN was found. Among households that reported individuals with level 0 MSN, the …

A Comparative Study Of Polyurethane Nanofibers With Different Patterns And Its Analogous Nanofibers Containing Mwcnts, Javier Macossay-Torres, Faheem A. Sheikh, Hassan Ahmad, Hern Kim, Gary L. Bowlin

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

Tissue engineering is a multidisciplinary field that has evolved in various dimensions in recent years. One of the main aspects in this field is the proper adjustment and final compatibility of implants at the target site of surgery. For this purpose, it is desired to have the materials fabricated at the nanometer scale, since these dimensions will ultimately accelerate the fixation of implants at the cellular level. In this study, electrospun polyurethane nanofibers and their analogous nanofibers containing MWCNTs are introduced for tissue engineering applications. Since MWCNTs agglomerate to form bundles, a high intensity sonication procedure was used to disperse …

Association Of Total And Differential White Blood Cell Counts To Development Of Type 2 Diabetes In Mexican Americans In Cameron County Hispanic Cohort, Kristina Vatcheva, Susan P. Fisher-Hoch, Mohammad H. Rahbar, Minjae Lee, Rene L. Olvera, Joseph B. Mccormick

School of Mathematical & Statistical Sciences Faculty Publications

Objective: To evaluate the relationship between total and differential White Blood Cell (WBC) counts with time to transition to type 2 diabetes in Mexican Americans using prospective data from the Cameron County Hispanic Cohort (CCHC).

Results: Multivariable Cox proportional hazards regression models revealed that obese Mexican-American cohort participants whose total WBC or granulocyte count increased over time had 1.39 and 1.35 times higher risk respectively of transition to type 2 diabetes when compared to overweight participants. The granulocyte or total WBC count in participants with BMI≥35 were significant risk factors for transition to type 2 diabetes.

Conclusions: Increased total WBC …

Dna Cyclization And Looping In The Wormlike Limit: Normal Modes And The Validity Of The Harmonic Approximation, Stefan M. Giovan, Andreas Hanke, Stephen D. Levene

Physics & Astronomy Faculty Publications

For much of the last three decades, Monte Carlo-simulation methods have been the standard approach for accurately calculating the cyclization probability, J, or J factor, for DNA models having sequence-dependent bends or inhomogeneous bending flexibility. Within the last 10 years approaches based on harmonic analysis of semi-flexible polymer models have been introduced, which offer much greater computational efficiency than Monte Carlo techniques. These methods consider the ensemble of molecular conformations in terms of harmonic fluctuations about a well-defined elastic-energy minimum. However, the harmonic approximation is only applicable for small systems, because the accessible conformation space of larger systems is increasingly …

Completion Of Hankel Partial Contractions Of Non-Extremal Type, In Hyoun Kim, Seonguk Yoo, Jasang Yoon

School of Mathematical & Statistical Sciences Faculty Publications

A matrix completion problem has been exploited amply because of its abundant applications and the analysis of contractions enables us to have insight into structure and space of operators. In this article, we focus on a specific completion problem related to Hankel partial contractions. We provide concrete necessary and sufficient conditions for the existence of completion of Hankel partial contractions for both extremal and non-extremal types with lower dimensional matrices. Moreover, we give a negative answer for the conjecture presented in [8]. For our results, we use several tools such as the Nested Determinants Test (or Choleski's Algorithm), the Moore-Penrose …

The Rider (2015-08-31), Jesus Sanchez

The Rider Archives

Vol.1 No.1

Phase-Coherent Mapping Of Gravitational-Wave Backgrounds Using Ground-Based Laser Interferometers, Joseph D. Romano, Stephen R. Taylor, Neil Cornish, Jonathan Gair, Chiara M. F. Mingarelli, Rutger Van Haasteren

Physics & Astronomy Faculty Publications

We extend the formalisms developed in Gair et al. [1] and Cornish and van Haasteren [2] to create maps of gravitational-wave backgrounds using a network of ground-based laser interferometers. We show that in contrast to pulsar timing arrays, which are insensitive to the curl modes of the background, a network of ground-based interferometers is sensitive to both the gradient and curl components. The spatial separation of a network of interferometers, or of a single interferometer at different times during its rotational and orbital motion around the Sun, allows for recovery of both components. We derive expressions for the response functions …

Discovery And Follow-Up Of Rotating Radio Transients With The Green Bank And Lofar Telescopes, C. Karako-Argaman, V. M. Kaspi, R. S. Lynch, J. W.T. Hessels, V. I. Kondratiev, M. A. Mclaughlin, S. M. Ransom, A. M. Archibald, J. Boyles, Fredrick Jenet

Physics & Astronomy Faculty Publications

We have discovered 21 Rotating Radio Transients (RRATs) in data from the Green Bank Telescope (GBT) 350 MHz Drift-scan and the Green Bank North Celestial Cap pulsar surveys using a new candidate sifting algorithm. RRATs are pulsars with sporadic emission that are detected through their bright single pulses rather than Fourier domain searches. We have developed RRATtrap, a single-pulse sifting algorithm that can be integrated into pulsar survey data analysis pipelines in order to find RRATs and Fast Radio Bursts. We have conducted follow-up observations of our newly discovered sources at several radio frequencies using the GBT and Low Frequency …

Higgs Boson Equation In De Sitter Spacetime: Numerical Investigation Of Bubbles Using Gpus, Jacob N. Banda

Theses and Dissertations - UTB/UTPA

The Higgs field, along with its corresponding boson, represent a milestone for modern day particle physics. In this work we consider the Higgs boson equation in de Sitter spacetime. Previous work by K. Yagdjian [23] has formulated sufficient conditions for the existence of the zeros of global solutions in the interior of their supports. In searching for such solutions, we turn to heterogeneous parallel computing, which allows for faster computation through graphical processing units (GPUs). Armed with general-purpose computation on graphics hardware (GPGPU) techniques and explicit numerical schemes, we approximate solutions of the equation for the Higgs boson along with …

Latina Mothers' Expectations And Perceptions About A Dual Language Education In The Rio Grande Valley, Rosalinda A. Cobarrubias

Theses and Dissertations - UTB/UTPA

The initial purpose of this study was to identify Latino parents’ expectations and perceptions of a dual language program in the Lower Rio Grande Valley. All of the Latino parents of children in one dual language program were invited to participate in the study. The parents who agreed to participate in the study were all mothers. Consequently, only the perceptions and expectations of Latina mothers were explored. The chosen method of this study was qualitative research to explore the expectations and perceptions of the dual language program of twenty Latina mothers of Mexican descent. There were eleven English dominant Latina …

Analysis Of Variables Related To Corridor Use By Ocelots And Bobcats In South Texas, Sarah E. Nordlof

Theses and Dissertations - UTB/UTPA

Biologists estimate that less than 50 endangered ocelots (Leopardus pardalis) remain in the United States, restricted to two small populations in Cameron and Willacy Counties located in deep south Texas. Conversely, bobcats (Lynx rufus) are abundant in south Texas; however, two of the biggest threats to both species are vehicle collisions and habitat fragmentation. To mitigate these threats, the installation of wildlife crossings has been proposed to decrease the number of road mortalities, and wildlife corridors have been suggested as a useful tool for providing increased habitat connectivity. However, research on ocelot use of corridors and wildlife crossings in Texas …

On Various Solutions To A (2+1) Dimensional General Camassa-Holm Equation, Eric J. Tovar

Theses and Dissertations - UTB/UTPA

We study a (2+1)-dimensional generalized Camassa-Holm (2dgCH) equation with both quadratic and cubic nonlinearity. We derive a peaked soliton (peakon) solution and multi-peakon solutions. In particular, the two-peakon dynamical system is explicitly presented and their collisions are investigated in detail. We also find weak kink and kink-peakon interactional solutions. Furthermore, we study all possible smooth one-soliton solutions for the system.

Financial Market And Pricing Of Emerging Financial Derivatives: A Mathematical Approach, Haicheng Gu

Theses and Dissertations - UTB/UTPA

Pricing has been one of the key problems of financial market theory. With the development of the modern financial market, various new financial derivatives have been created and need to be priced properly. In the thesis, we are going to use several mathematical tools to investigate the essential structure of the financial market and models for financial derivatives.

Nonlinear Dynamics Of Electrostatically Actuated M/Nems Plates To Include Casimir And Van Der Waals Effects, Reynaldo Oyervides

Theses and Dissertations - UTB/UTPA

The amplitude-frequency response and voltage-amplitude response of electrostatically actuated micro and nano-electromechanical systems (M/NEMS) clamped circular plates are investigated. The system is actuated by soft AC voltage at frequency near half natural frequency of the plate, and another case near natural frequency of the plate, they resulting in primary and parametric resonances of the system, respectively. The system is first analytically modeled using the Method of Multiple Scales (MMS). MMS results are then compared to Reduced Order Model (ROM) method frequency response numerical simulations. Besides MMS and ROM, time response simulations are conducted. The agreement of the frequency responses of …