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University of Texas Rio Grande Valley

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Articles 1951 - 1980 of 2419

Full-Text Articles in Physical Sciences and Mathematics

Swift Follow-Up Observations Of Candidate Gravitational-Wave Transient Events, P. A. Evans, J. K. Fridriksson, N. Gehrels, J. Homan, J. P. Osborne, M. Siegel, A. Beardmore, P. Handbauer, J. Gelbord, J. A. Kennea, M. Smith, Q. Zhu, J. Aasi, J. Abadie, B. P. Abbott, R. Abbott, T. D. Abbott, M. Abernathy, T. Accadia, F. Acernese, C. Adams, T. Adams, P. Addesso, R. Adhikari, C. Affeldt, M. Agathos, K. Agatsuma, P. Ajith, B. Allen, A. Allocca Dec 2012

Swift Follow-Up Observations Of Candidate Gravitational-Wave Transient Events, P. A. Evans, J. K. Fridriksson, N. Gehrels, J. Homan, J. P. Osborne, M. Siegel, A. Beardmore, P. Handbauer, J. Gelbord, J. A. Kennea, M. Smith, Q. Zhu, J. Aasi, J. Abadie, B. P. Abbott, R. Abbott, T. D. Abbott, M. Abernathy, T. Accadia, F. Acernese, C. Adams, T. Adams, P. Addesso, R. Adhikari, C. Affeldt, M. Agathos, K. Agatsuma, P. Ajith, B. Allen, A. Allocca

Physics and Astronomy Faculty Publications and Presentations

We present the first multi-wavelength follow-up observations of two candidate gravitational-wave (GW) transient events recorded by LIGO and Virgo in their 2009-2010 science run. The events were selected with low latency by the network of GW detectors (within less than 10 minutes) and their candidate sky locations were observed by the Swift observatory (within 12 hr). Image transient detection was used to analyze the collected electromagnetic data, which were found to be consistent with background. Off-line analysis of the GW data alone has also established that the selected GW events show no evidence of an astrophysical origin; one of them …


Synthesis And Luminescence Properties Of Core-Shell Structured (Lanthanum(1-X)Europium(X))(2)Zirconium Heptoxid[At]Yttrium Orthoborate Spherical Nanoparticles, Suresh Babu Alaparthi Dec 2012

Synthesis And Luminescence Properties Of Core-Shell Structured (Lanthanum(1-X)Europium(X))(2)Zirconium Heptoxid[At]Yttrium Orthoborate Spherical Nanoparticles, Suresh Babu Alaparthi

Theses and Dissertations - UTB/UTPA

Many rare earth compounds have photoluminescent characteristics for various important applications. In this study, europium doped La2Zr2O7 nanoparticles were first synthesized morphology-controllably by using a molten-salt synthesis method. These nanoparticles were used as the core for coating with YBO3 shell. We then explored the effect of different experimental processing parameters, such as annealing temperatures, reaction times and different ratios of salt mixtures on the structure and morphology of these nanoparticles. The overall core size and shell thickness can be controlled by varying the reactant concentration both the core and shell material. These core@shell nanoparticles were then characterized mainly using power …


Domain Independent Ordering Of Narrative Events, Lucian T. Silcox Dec 2012

Domain Independent Ordering Of Narrative Events, Lucian T. Silcox

Theses and Dissertations - UTB/UTPA

A key aspect towards gaining a rich understanding of a text is the ability to order the events that occur in the narrative. For us, as readers, this is a simple task, accomplished without effort by recognizing subtle contextual and linguistic clues. For natural language systems, however, the task is considerably more difficult. It is the intent of this research to automate the process of annotating and ordering temporal events in a narrative, and to measure the success of techniques trained on news articles when applied to less sequentially-structured texts. We build on the earlier work of Mani et al …


Generalizing Agent Plans And Behaviors With Automated Staged Observation In The Real-Time Strategy Game Starcraft, Zackary A. Gill Dec 2012

Generalizing Agent Plans And Behaviors With Automated Staged Observation In The Real-Time Strategy Game Starcraft, Zackary A. Gill

Theses and Dissertations - UTB/UTPA

In this thesis we investigate the processes involved in learning to play a game. It was inspired by two observations about how human players learn to play. First, learning the domain is intertwined with goal pursuit. Second, games are designed to ramp up in complexity, walking players through a gradual cycle of acquiring, refining, and generalizing knowledge about the domain. This approach does not rely on traces of expert play. We created an integrated planning, learning and execution system that uses StarCraft as its domain. The planning module creates command/event groupings based on the data received. Observations of unit behavior …


A Comparison Of Display Techniques For Large Graphs, Ana Rocio Pena Dec 2012

A Comparison Of Display Techniques For Large Graphs, Ana Rocio Pena

Theses and Dissertations - UTB/UTPA

Visualizing information focuses on the display of data in order to provide the user a representation that provides understanding of the data. Information visualization systems typically couple interaction mechanisms for providing overviews of the data with more detailed information through a zooming interface. This thesis compares three different techniques for displaying graphs provided by the prefuse visualization system: force-directed node positioning, radial node positioning, and a tree view of graphs. Using a large, real world data set from the South Texas College’s Distance Education department, the three visualization techniques are compared for a set of tasks that users routinely need …


Search For Gravitational Waves Associated With Gamma-Ray Bursts During Ligo Science Run 6 And Virgo Science Runs 2 And 3, J. Abadie, B. P. Abbott, R. Abbott, T. D. Abbott, M. Abernathy, T. Accadia, F. Acernese, C. Adams, R. X. Adhikari, C. Affeldt, M. Agathos, K. Agatsuma, P. Ajith, B. Allen, E. Amador Ceron, D. Amariutei, S. B. Anderson, W. G. Anderson, K. Arai, M. A. Arain, M. C. Araya, S. M. Aston, P. Astone, D. Atkinson, P. Aufmuth, C. Aulbert, B. E. Aylott, S. Babak, P. Baker, G. Ballardin Nov 2012

Search For Gravitational Waves Associated With Gamma-Ray Bursts During Ligo Science Run 6 And Virgo Science Runs 2 And 3, J. Abadie, B. P. Abbott, R. Abbott, T. D. Abbott, M. Abernathy, T. Accadia, F. Acernese, C. Adams, R. X. Adhikari, C. Affeldt, M. Agathos, K. Agatsuma, P. Ajith, B. Allen, E. Amador Ceron, D. Amariutei, S. B. Anderson, W. G. Anderson, K. Arai, M. A. Arain, M. C. Araya, S. M. Aston, P. Astone, D. Atkinson, P. Aufmuth, C. Aulbert, B. E. Aylott, S. Babak, P. Baker, G. Ballardin

Physics and Astronomy Faculty Publications and Presentations

We present the results of a search for gravitational waves associated with 154 gamma-ray bursts (GRBs) that were detected by satellite-based gamma-ray experiments in 2009-2010, during the sixth LIGO science run and the second and third Virgo science runs. We perform two distinct searches: a modeled search for coalescences of either two neutron stars or a neutron star and black hole, and a search for generic, unmodeled gravitational-wave bursts. We find no evidence for gravitational-wave counterparts, either with any individual GRB in this sample or with the population as a whole. For all GRBs we place lower bounds on the …


Raman Spectroscopy Of Isotactic Polypropylene-Halloysite Nanocomposites, Elamin E. Ibrahim, Dorina M. Chipara, Ram Thapa, Karen Lozano, Mircea Chipara Nov 2012

Raman Spectroscopy Of Isotactic Polypropylene-Halloysite Nanocomposites, Elamin E. Ibrahim, Dorina M. Chipara, Ram Thapa, Karen Lozano, Mircea Chipara

Physics and Astronomy Faculty Publications and Presentations

Raman spectroscopy investigations on nanocomposites obtained by dispersing halloysite within isotactic polypropylene are reported. A detailed analysis of the modifications of the regularity band associated to the polymeric matrix is presented. The Raman lines assigned to the polymeric matrix are broadened and weakened as the loading with halloysite is increased. The analysis of Raman lines indicates that the polymeric matrix becomes less crystalline upon the loading with halloysite and that the nanofiller is experiencing a weak dehydration upon dispersion within the polymeric matrix, probably due to the related thermal processing used to achieve the dispersion of halloysite. © 2012 Elamin …


Titanium Dioxide Nanofibers And Microparticles Containing Nickel Nanoparticles, Faheem A. Sheikh, Javier Macossay-Torres, M. A. Kanjwal, Abdalla Abdal-Hay, Mudasir A. Tantry, Hern Kim Nov 2012

Titanium Dioxide Nanofibers And Microparticles Containing Nickel Nanoparticles, Faheem A. Sheikh, Javier Macossay-Torres, M. A. Kanjwal, Abdalla Abdal-Hay, Mudasir A. Tantry, Hern Kim

Chemistry Faculty Publications and Presentations

The present study reports on the introduction of various nanocatalysts containing nickel (Ni) nanoparticles (NPs) embedded within TiO2 nanofibers and TiO2 microparticles. Typically, a sol-gel consisting of titanium isopropoxide and Ni NPs was prepared to produce TiO2 nanofibers by the electrospinning process. Similarly, TiO2 microparticles containing Ni were prepared using a sol-gel syntheses process. The resultant structures were studied by SEM analyses, which confirmed well-obtained nanofibers and microparticles. Further, the XRD results demonstrated the crystalline feature of both TiO2 and Ni in the obtained composites. Internal morphology of prepared nanofibers and microparticles containing Ni NPs was characterized by TEM, which …


High Prevalence Of Subclinical Atherosclerosis By Carotid Ultrasound Among Mexican Americans: Discordance With 10-Year Risk Assessment Using The Framingham Risk Score, Susan T. Laing, Beverly Smulevitz, Kristina Vatcheva, Anne R. Rentfro, David D. Mcpherson, Susan P. Fisher-Hoch, Joseph B. Mccormick Nov 2012

High Prevalence Of Subclinical Atherosclerosis By Carotid Ultrasound Among Mexican Americans: Discordance With 10-Year Risk Assessment Using The Framingham Risk Score, Susan T. Laing, Beverly Smulevitz, Kristina Vatcheva, Anne R. Rentfro, David D. Mcpherson, Susan P. Fisher-Hoch, Joseph B. Mccormick

School of Mathematical and Statistical Sciences Faculty Publications and Presentations

Background: Framingham risk scores (FRS) were validated in a mostly Caucasian population. Evaluation of subclinical atherosclerosis by carotid ultrasound may improve ascertainment of risk in nonwhite populations. This study aimed to evaluate carotid intima-media thickness (cIMT) and carotid plaquing among Mexican Americans, and to correlate these markers with coronary risk factors and the FRS.

Methods/results: Participants (n = 141) were drawn from the Cameron County Hispanic Cohort. Carotid artery ultrasound was performed and cIMT measured. Carotid plaque was defined as areas of thickening >50% of the thickness of the surrounding walls. Mean age was 53.1 ± 11.7 years (73.8% female). …


Modeling And Simulation Of Pressure Waves Generated By Nano-Thermite Reactions, Karen S. Martirosyan, Maxim Zyskin, Charles M. Jenkins, Yasuyuki Horie Nov 2012

Modeling And Simulation Of Pressure Waves Generated By Nano-Thermite Reactions, Karen S. Martirosyan, Maxim Zyskin, Charles M. Jenkins, Yasuyuki Horie

Physics and Astronomy Faculty Publications and Presentations

This paper reports the modeling of pressure waves from the explosive reaction of nano-thermites consisting of mixtures of nanosized aluminum and oxidizer granules. Such nanostructured thermites have higher energy density (up to 26 kJ/cm3) and can generate a transient pressure pulse four times larger than that from trinitrotoluene (TNT) based on volume equivalence. A plausible explanation for the high pressure generation is that the reaction times are much shorter than the time for a shock wave to propagate away from the reagents region so that all the reaction energy is dumped into the gaseous products almost instantaneously and thereby a …


Tornado Warnings In Three Southern States: A Qualitative Analysis Of Public Response Patterns, William Donner, Havidan Rodriguez, Walter Diaz Oct 2012

Tornado Warnings In Three Southern States: A Qualitative Analysis Of Public Response Patterns, William Donner, Havidan Rodriguez, Walter Diaz

Sociology Faculty Publications and Presentations

Recent research in three Southern states supplied data describing the role community structure and culture played in shaping public response to tornado risks. The following study identifies and describes how residents received, made sense of, and ultimately used information to make decisions about responding to warnings. In addition to a range of theoretical concerns, research was also intended to develop a set of safety policies derived from what the data reveals about the social psychology of risk perception, economic constraints to shelter, and the cultural aspects of response.Data analysis reveals a diverse set of social factors governing community response to …


An Expeditious Iodine-Catalyzed Synthesis Of 3-Pyrrole-Substituted 2-Azetidinones, Debasish Bandyopadhyay, Jessica Cruz, Ram N. Yadav, Bimal K. Banik Oct 2012

An Expeditious Iodine-Catalyzed Synthesis Of 3-Pyrrole-Substituted 2-Azetidinones, Debasish Bandyopadhyay, Jessica Cruz, Ram N. Yadav, Bimal K. Banik

Chemistry Faculty Publications and Presentations

2-Azetidinones and pyrroles are two highly important classes of molecules in organic and medicinal chemistry. A green and practical method for the synthesis of 3-pyrrole-substituted 2-azetidinones using catalytic amounts of molecular iodine under microwave irradiation has been developed. Following this method, a series of 3-pyrrole-substituted 2-azetidinones have been synthesized with a variety of substituents at N-1 and at C-4. The procedure is equally effective for mono-as well as polyaromatic groups at the N-1 position of the 2-azetidinone ring. The C-4 substituent has no influence either on the yield or the rate of the reaction. Optically pure 3-pyrrole-substituted 2-azetidinones have also …


Four Highly Dispersed Millisecond Pulsars Discovered In The Arecibo Palfa Galactic Plane Survey, F. Crawford, K. Stovall, A. G. Lyne, B. W. Stappers, D. J. Nice, I. H. Stairs, P. Lazarus, J. W.T. Hessels, P. C.C. Freire, B. Allen, N. D.R. Bhat, S. Bogdanov, A. Brazier, F. Camilo, D. J. Champion, S. Chatterjee, I. Cognard, J. M. Cordes, J. S. Deneva, G. Desvignes, F. A. Jenet, V. M. Kaspi, B. Knispel, M. Kramer, J. Van Leeuwen, D. R. Lorimer, R. Lynch, M. A. Mclaughlin, S. M. Ransom, P. Scholz Sep 2012

Four Highly Dispersed Millisecond Pulsars Discovered In The Arecibo Palfa Galactic Plane Survey, F. Crawford, K. Stovall, A. G. Lyne, B. W. Stappers, D. J. Nice, I. H. Stairs, P. Lazarus, J. W.T. Hessels, P. C.C. Freire, B. Allen, N. D.R. Bhat, S. Bogdanov, A. Brazier, F. Camilo, D. J. Champion, S. Chatterjee, I. Cognard, J. M. Cordes, J. S. Deneva, G. Desvignes, F. A. Jenet, V. M. Kaspi, B. Knispel, M. Kramer, J. Van Leeuwen, D. R. Lorimer, R. Lynch, M. A. Mclaughlin, S. M. Ransom, P. Scholz

Physics and Astronomy Faculty Publications and Presentations

We present the discovery and phase-coherent timing of four highly dispersed millisecond pulsars (MSPs) from the Arecibo PALFA Galactic plane survey: PSRs J1844+0115, J1850+0124, J1900+0308, and J1944+2236. Three of the four pulsars are in binary systems with low-mass companions, which are most likely white dwarfs, and which have orbital periods on the order of days. The fourth pulsar is isolated. All four pulsars have large dispersion measures (DM >100 pccm-3), are distant (≳ 3.4kpc), faint at 1.4GHz (≲ 0.2mJy), and are fully recycled (with spin periods P between 3.5 and 4.9ms). The three binaries also have very small orbital eccentricities, …


Two Millisecond Pulsars Discovered By The Palfa Survey And A Shapiro Delay Measurement, J. S. Deneva, P. C.C. Freire, J. M. Cordes, A. G. Lyne, S. M. Ransom, I. Cognard, F. Camilo, D. J. Nice, I. H. Stairs, B. Allen, N. D.R. Bhat, S. Bogdanov, A. Brazier, D. J. Champion, S. Chatterjee, F. Crawford, G. Desvignes, J. W.T. Hessels, F. A. Jenet, V. M. Kaspi, B. Knispel, M. Kramer, P. Lazarus, J. Van Leeuwen, D. R. Lorimer, R. S. Lynch, M. A. Mclaughlin, P. Scholz, X. Siemens, B. W. Stappers Sep 2012

Two Millisecond Pulsars Discovered By The Palfa Survey And A Shapiro Delay Measurement, J. S. Deneva, P. C.C. Freire, J. M. Cordes, A. G. Lyne, S. M. Ransom, I. Cognard, F. Camilo, D. J. Nice, I. H. Stairs, B. Allen, N. D.R. Bhat, S. Bogdanov, A. Brazier, D. J. Champion, S. Chatterjee, F. Crawford, G. Desvignes, J. W.T. Hessels, F. A. Jenet, V. M. Kaspi, B. Knispel, M. Kramer, P. Lazarus, J. Van Leeuwen, D. R. Lorimer, R. S. Lynch, M. A. Mclaughlin, P. Scholz, X. Siemens, B. W. Stappers

Physics and Astronomy Faculty Publications and Presentations

We present two millisecond pulsar discoveries from the PALFA survey of the Galactic plane with the Arecibo telescope. PSR J1955+2527 is an isolated pulsar with a period of 4.87ms, and PSR J1949+3106 has a period of 13.14ms and is in a 1.9day binary system with a massive companion. Their timing solutions, based on 4years of timing measurements with the Arecibo, Green Bank, Nançay, and Jodrell Bank telescopes, allow precise determination of spin and astrometric parameters, including precise determinations of their proper motions. For PSR J1949+3106, we can clearly detect the Shapiro delay. From this we measure the pulsar mass to …


Cop1 Mediates The Coordination Of Root And Shoot Growth By Light Through Modulation Of Pin1- And Pin2-Dependent Auxin Transport In Arabidopsis, Massimiliano Sassi, Yanfen Lu, Yonghong Zhang, Juan Wang, Pankaj Dhonukshe, Ikram Blilou, Minqiu Dai, Juan Li, Ximing Gong, Yvon Jaillais, Xuhong Yu, Jan Traas, Ida Ruberti, Haiyang Wang, Ben Scheres, Teva Vernoux, Jian Xu Sep 2012

Cop1 Mediates The Coordination Of Root And Shoot Growth By Light Through Modulation Of Pin1- And Pin2-Dependent Auxin Transport In Arabidopsis, Massimiliano Sassi, Yanfen Lu, Yonghong Zhang, Juan Wang, Pankaj Dhonukshe, Ikram Blilou, Minqiu Dai, Juan Li, Ximing Gong, Yvon Jaillais, Xuhong Yu, Jan Traas, Ida Ruberti, Haiyang Wang, Ben Scheres, Teva Vernoux, Jian Xu

Chemistry Faculty Publications and Presentations

When a plant germinates in the soil, elongation of stem-like organs is enhanced whereas leaf and root growth is inhibited. How these differential growth responses are orchestrated by light and integrated at the organismal level to shape the plant remains to be elucidated. Here, we show that light signals through the master photomorphogenesis repressor COP1 to coordinate root and shoot growth in Arabidopsis. In the shoot, COP1 regulates shoot-to-root auxin transport by controlling the transcription of the auxin efflux carrier gene PIN-FORMED1 (PIN1), thus appropriately tuning shoot-derived auxin levels in the root. This in turn directly influences root elongation and …


The Critical Coupling Likelihood Method: A New Approach For Seamless Integration Of Environmental And Operating Conditions Of Gravitational Wave Detectors Into Gravitational Wave Searches, Cesar A. Costa, Cristina V. Torres Sep 2012

The Critical Coupling Likelihood Method: A New Approach For Seamless Integration Of Environmental And Operating Conditions Of Gravitational Wave Detectors Into Gravitational Wave Searches, Cesar A. Costa, Cristina V. Torres

Physics and Astronomy Faculty Publications and Presentations

Any search effort for gravitational waves (GWs) using interferometric detectors like LIGO needs to be able to identify if and when noise couples into the detector’s output signal. The critical coupling likelihood (CCL) method has been developed to characterize potential noise coupling and in the future aid GW search efforts. By testing two hypotheses about pairs of channels, CCL is able to identify undesirable coupled instrumental noise from potential GW candidates. Our preliminary results show that CCL can associate up to ∼80% of observed artifacts with SNR ⩾ 8 with local noise sources, while reducing the duty cycle of the …


Improving Stem Education In Research: Preliminary Report On The Development Of A Computer-Assisted Student-Mentor Research Community, David A. Rios, Artem Chebotko, Christine Reilly, Ralph Carlson, Emmett Tomai, Amy A. Weimer, Nicholas Weimer, Thomas Pearson, Francis Andoh-Baidoo, Robert Winkle, David Ammons, Joanne Rampersad-Ammons Sep 2012

Improving Stem Education In Research: Preliminary Report On The Development Of A Computer-Assisted Student-Mentor Research Community, David A. Rios, Artem Chebotko, Christine Reilly, Ralph Carlson, Emmett Tomai, Amy A. Weimer, Nicholas Weimer, Thomas Pearson, Francis Andoh-Baidoo, Robert Winkle, David Ammons, Joanne Rampersad-Ammons

Computer Science Faculty Publications and Presentations

Research education in STEM disciplines currently suffers from 1) The inability to feasibly collect highly detailed data on both the student’s and mentor’s activities; 2) The lack of tools to assist students and mentors in organizing and managing their research activities and environments; and 3) The inability to correlate a student’s assessment results with their actual research activities. Together these three problems act to impede both the improvement and educational quality of student research experiences. We propose a computer-assisted student-mentor research community as a solution to these problems. Within this community setting, students and their mentors are provided tools to …


Implications For The Origin Of Grb 051103 From Ligo Observations, J. Abadie, B. P. Abbott, T. D. Abbott, R. Abbott, M. Abernathy, C. Adams, R. Adhikari, C. Affeldt, P. Ajith, B. Allen, G. S. Allen, E. Amador Ceron, D. Amariutei, R. S. Amin, S. B. Anderson, W. G. Anderson, K. Arai, M. A. Arain, M. C. Araya, S. M. Aston, D. Atkinson, P. Aufmuth, C. Aulbert, B. E. Aylott, S. Babak, P. Baker, S. Ballmer, D. Barker, S. Barnum, B. Barr Aug 2012

Implications For The Origin Of Grb 051103 From Ligo Observations, J. Abadie, B. P. Abbott, T. D. Abbott, R. Abbott, M. Abernathy, C. Adams, R. Adhikari, C. Affeldt, P. Ajith, B. Allen, G. S. Allen, E. Amador Ceron, D. Amariutei, R. S. Amin, S. B. Anderson, W. G. Anderson, K. Arai, M. A. Arain, M. C. Araya, S. M. Aston, D. Atkinson, P. Aufmuth, C. Aulbert, B. E. Aylott, S. Babak, P. Baker, S. Ballmer, D. Barker, S. Barnum, B. Barr

Physics and Astronomy Faculty Publications and Presentations

We present the results of a LIGO search for gravitational waves (GWs) associated with GRB 051103, a short-duration hard-spectrum gamma-ray burst (GRB) whose electromagnetically determined sky position is coincident with the spiral galaxy M81, which is 3.6Mpc from Earth. Possible progenitors for short-hard GRBs include compact object mergers and soft gamma repeater (SGR) giant flares. A merger progenitor would produce a characteristic GW signal that should be detectable at a distance of M81, while GW emission from an SGR is not expected to be detectable at that distance. We found no evidence of a GW signal associated with GRB 051103. …


A New Algorithm For Dna Motif Detection, Ran Ding Aug 2012

A New Algorithm For Dna Motif Detection, Ran Ding

Theses and Dissertations - UTB/UTPA

Nowadays, people are more and more concentrated on the research of deoxyribonucleic acid(DNA). And a very important problem is how to identify the DNA performance. A DNA sequence contains lots of genes, and every gene has a regulatory region. This regulatory region contains the transcription factor binding sites (TFBS) which is also known as motif. How to identify this motif becomes a very important problem. There are many efficient methods and tools are dedicated to the research of DNA motif detection. In this paper, we will introduce a new method of DNA motif detection which basically is an advanced approximate …


Measuring The Impact Of Narrative On Player's Presence And Immersion In A First Person Game Environment, Raul Huerta Aug 2012

Measuring The Impact Of Narrative On Player's Presence And Immersion In A First Person Game Environment, Raul Huerta

Theses and Dissertations - UTB/UTPA

In the virtual environments (VE) literature, presence has been described as the feeling whereby an individual feels as if he or she is actually in the VE. In the videogame literature, the related concept of immersion is viewed as an effect facilitating player engagement. This thesis examines how narrative and graphics quality influence presence and immersion in a first person game. Three levels of narrative and graphics quality are used in an empirical study: text narrative with high quality graphics, no text narrative with high quality graphics, and no text narrative with low quality graphics. Results showed that there is …


Synthesis And Characterization Of Biodegradable Electrospun Polyurethanes For Biomedical Applications, Xujun Zhang Aug 2012

Synthesis And Characterization Of Biodegradable Electrospun Polyurethanes For Biomedical Applications, Xujun Zhang

Theses and Dissertations - UTB/UTPA

Two types of polyesters [(Poly(ε-caprolactone) and Poly(δ-valerolactone)] were synthesized by ring-opening polymerization with diethylene glycol as a initiator and stannous octate as a catalyst. The corresponding polyurethanes were synthesized by two-step polymerization with 1,4-diisocyanate butane (BDI) and reacted with 1,4-diamino butane (Putrescine) chain extender. The polymers were characterized by Proton Nuclear Magnetic Resonance (1H NMR), Fourier Transform Infrared Spectroscopy (FT-IR), Raman Spectroscopy, Size-exclusive Chromatography (SEC), Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). The resulting polyurethanes were fabricated into nanofibers using an electrospinning technique. The morphological, structural characterizations and thermal properties of the bulk polyurethanes and electrospun polyurethanes nanofibers were …


Convolution Backprojection For Sar Image Formation, Timothy P. Ray Aug 2012

Convolution Backprojection For Sar Image Formation, Timothy P. Ray

Theses and Dissertations - UTB/UTPA

Convolution Back Projection (CBP) is an imaging algorithm, which can be applied to data gathered by a Synthetic Aperture Radar (SAR) system to produce high resolution images. The Mathematics of CBP was first studied in the context of tomographic image reconstruction for medical applications. CBP image processing has also been applied to a variety of other fields, such as seismic imaging, sonar, and radio astronomy. In terms of SAR image processing algorithms, CBP is far less efficient than direct Fourier Inversion Algorithms. The purpose of this thesis is to study the CBP algorithm as it is applied to SAR image …


Electrospun Biocompatible Polyurethanes With The Addition Of Multi-Walled Carbon Nanotubes, Travis Cantu Aug 2012

Electrospun Biocompatible Polyurethanes With The Addition Of Multi-Walled Carbon Nanotubes, Travis Cantu

Theses and Dissertations - UTB/UTPA

Three different Polyurethanes (PUs) Lycra®, HydroThaneTM, and BioSpan®, were electrospun and characterized using Scanning electron microscope (SEM), transmission electron microscope (TEM), Fourier transform-infrared spectroscopy (FTIR), & Raman spectroscopy. Nanofiber composites were made by incorporating MWCNTs at three different concentration 0.1wt% 0.5wt% and 1.0wt% to the three PUs. These samples were characterized and mechanical and thermal test were done. The TEM images showed MWCNT bundling in the polymer matrix at the highest concentration, the FTIR showed shifts in characteristic urethane bands indicating an interaction with the polymer and MWCNTs. Mechanical test showed a decrease in the Young’s modulus (E’) in most …


Synthesis Of Novel Bis-Β-Lactams, Jocabed Marquez Aug 2012

Synthesis Of Novel Bis-Β-Lactams, Jocabed Marquez

Theses and Dissertations - UTB/UTPA

This study presents the synthesis and structure of newly discovered β-lactams and the mechanism of their synthesis via the Staudinger reaction. β-lactams known as 2-azetidinones, are four membered cyclic amides that have been extensively used and recognized as the central motif of the β-lactam antibiotics, the most widely employed family of antimicrobial agent to date. The Staudinger reaction involves the cycloaddition between an acid chloride with an imine, in presence of a tertiary base. The possibility of cooperative effects from two therapeutic functionalities in drug molecules, has prompted interest in the synthesis of Bis-β-lactams. The synthesis of 2 novel Bis-β-lactams …


Microwave-Induced Bismuth Nitrate-Catalyzed Multicomponent Reaction Toward Heterocycles, Ashwini Bobbala Aug 2012

Microwave-Induced Bismuth Nitrate-Catalyzed Multicomponent Reaction Toward Heterocycles, Ashwini Bobbala

Theses and Dissertations - UTB/UTPA

The microwave-induced reaction for the synthesis of nitrogen containing heterocyclesis very important in medicinal chemistry. The synthesis of various other valuable compounds is also done by employing this reaction. The aza Diels-Alder reaction is one of the most powerful synthetic tools for the synthesis of nitrogen containing heterocycles. The main goal of the research is to synthesize the nitrogen containing heterocycles using Bismuth nitrate as the catalyst in the presence of microwave irradiation. In the present study we explore the catalytic activity of bismuth nitrate and the role of microwave reactor in the synthesis of 2, 3-diaryl substituted bicyclic octanone …


Missed Opportunities For Diagnosis And Treatment Of Diabetes, Hypertension, And Hypercholesterolemia In A Mexican American Population, Cameron County Hispanic Cohort, 2003-2008, Susan P. Fisher-Hoch, Kristina Vatcheva, Susan T. Laing, Monir Hossain, M Hossein Rahbar, Craig Hanis, H Shelton Brown, Anne R. Rentfro, Belinda M. Reininger, Joseph B. Mccormick Aug 2012

Missed Opportunities For Diagnosis And Treatment Of Diabetes, Hypertension, And Hypercholesterolemia In A Mexican American Population, Cameron County Hispanic Cohort, 2003-2008, Susan P. Fisher-Hoch, Kristina Vatcheva, Susan T. Laing, Monir Hossain, M Hossein Rahbar, Craig Hanis, H Shelton Brown, Anne R. Rentfro, Belinda M. Reininger, Joseph B. Mccormick

School of Mathematical and Statistical Sciences Faculty Publications and Presentations

Introduction

Diabetes, hypertension, and hypercholesterolemia are common chronic diseases among Hispanics, a group projected to comprise 30% of the US population by 2050. Mexican Americans are the largest ethnically distinct subgroup among Hispanics. We assessed the prevalence of and risk factors for undiagnosed and untreated diabetes, hypertension, and hypercholesterolemia among Mexican Americans in Cameron County, Texas.

Methods

We analyzed cross-sectional baseline data collected from 2003 to 2008 in the Cameron County Hispanic Cohort, a randomly selected, community-recruited cohort of 2,000 Mexican American adults aged 18 or older, to assess prevalence of diabetes, hypertension, and hypercholesterolemia; to assess the extent to …


New Approach To Time Domain Classification Of Broadband Noise In Gravitational Wave Data, S. Mukherjee, P. Rizwan, R. Biswas Jul 2012

New Approach To Time Domain Classification Of Broadband Noise In Gravitational Wave Data, S. Mukherjee, P. Rizwan, R. Biswas

Physics and Astronomy Faculty Publications and Presentations

Transient broadband noise in gravitational wave (GW) detectors-also known as noise triggers (referred to as triggers for brevity)-can often be a deterrant to the efficiency with which astrophysical search pipelines detect sources. It is important to understand their instrumental or environmental origin so that they could be eliminated or accounted for in the data. Since the number of triggers is large, data mining approaches such as clustering and classification are useful tools for this task. Classification of triggers based on a handful of discrete properties has been done in the past. A rich information content is available in the waveform …


Pt-Symmetric Talbot Effects, Hamidreza Ramezani, D. N. Christodoulides, V. Kovanis, I. Vitebskiy, Tsampikos Kottos Jul 2012

Pt-Symmetric Talbot Effects, Hamidreza Ramezani, D. N. Christodoulides, V. Kovanis, I. Vitebskiy, Tsampikos Kottos

Physics and Astronomy Faculty Publications and Presentations

We show that complex PT-symmetric photonic lattices can lead to a new class of self-imaging Talbot effects. For this to occur, we find that the input field pattern has to respect specific periodicities dictated by the symmetries of the system. While at the spontaneous PT-symmetry breaking point the image revivals occur at Talbot lengths governed by the characteristics of the passive lattice, at the exact phase it depends on the gain and loss parameter, thus allowing one to control the imaging process. © 2012 American Physical Society.


Derivative Couplings With Built-In Electron-Translation Factors: Application To Benzene, Shervin Fatehi, Joseph E. Subotnik Jul 2012

Derivative Couplings With Built-In Electron-Translation Factors: Application To Benzene, Shervin Fatehi, Joseph E. Subotnik

Chemistry Faculty Publications and Presentations

Derivative couplings are the essential quantities at the interface between electronic-structure calculations and nonadiabatic dynamics. Unfortunately, standard approaches for calculating these couplings usually neglect electronic motion, which can lead to spurious electronic transitions. Here we provide a general framework for correcting these anomalies by incorporating perturbative electron-translation factors (ETFs) into the atomic-orbital basis. For a range of representative organic molecules, we find that our ETF correction is often small but can be qualitatively important, especially for few-atom systems or highly symmetric molecules. Our method entails no additional computational cost, such that ETFs are “built-in,” and it is equivalent to a …


Discovery Of The Optical/Ultraviolet/Gamma-Ray Counterpart To The Eclipsing Millisecond Pulsar J1816+4510, D. L. Kaplan, K. Stovall, S. M. Ransom, M. S.E. Roberts, R. Kotulla, A. M. Archibald, C. M. Biwer, J. Boyles, L. Dartez, D. F. Day, A. J. Ford, A. Garcia, J. W.T. Hessels, F. A. Jenet, C. Karako, V. M. Kaspi, V. I. Kondratiev, D. R. Lorimer, R. S. Lynch, M. A. Mclaughlin, M. D.W. Rohr, X. Siemens, I. H. Stairs, J. Van Leeuwen Jul 2012

Discovery Of The Optical/Ultraviolet/Gamma-Ray Counterpart To The Eclipsing Millisecond Pulsar J1816+4510, D. L. Kaplan, K. Stovall, S. M. Ransom, M. S.E. Roberts, R. Kotulla, A. M. Archibald, C. M. Biwer, J. Boyles, L. Dartez, D. F. Day, A. J. Ford, A. Garcia, J. W.T. Hessels, F. A. Jenet, C. Karako, V. M. Kaspi, V. I. Kondratiev, D. R. Lorimer, R. S. Lynch, M. A. Mclaughlin, M. D.W. Rohr, X. Siemens, I. H. Stairs, J. Van Leeuwen

Physics and Astronomy Faculty Publications and Presentations

The energetic, eclipsing millisecond pulsar J1816+4510 was recently discovered in a low-frequency radio survey with the Green Bank Telescope. With an orbital period of 8.7hr and a minimum companion mass of 0.16M ⊙ , it appears to belong to an increasingly important class of pulsars that are ablating their low-mass companions. We report the discovery of the γ-ray counterpart to this pulsar and present a likely optical/ultraviolet counterpart as well. Using the radio ephemeris, we detect pulsations in the unclassified γ-ray source 2FGL J1816.5+4511, implying an efficiency of 25% in converting the pulsar's spin-down luminosity into γ-rays and adding PSR …