Digital Commons Network^™

Carbon Monoxide Adsorption On Platinum-Osmium And Platinum-Ruthenium-Osmium Mixed Nanoparticles, Nicholas Dimakis, Nestor E. Navarro, Eugene S. Smotkin

Physics & Astronomy Faculty Publications

Density functional calculations (DFT) on carbon monoxide (CO) adsorbed on platinum, platinum-osmium, and platinum-ruthenium-osmium nanoclusters are used to elucidate changes on the adsorbate internal bond and the carbon-metal bond, as platinum is alloyed with osmium and ruthenium atoms. The relative strengths of the adsorbate internal bond and the carbon-metal bond upon alloying, which are related to the DFT calculated C–O and C–Pt stretching frequencies, respectively, cannot be explained by the traditional 5σ-donation/2π*-back-donation theoretical model. Using a modified π-attraction σ-repulsion mechanism, we ascribe the strength of the CO adsorbate internal bond to changes in the polarization of the adsorbate-substrate hybrid orbitals …

Reactive Self-Heating Model Of Aluminum Spherical Nanoparticles, Karen S. Martirosyan, Maxim Zyskin

Physics & Astronomy Faculty Publications

Aluminum-oxygen reaction is important in highly energetic and high pressure generating systems. Recent experiments with nanostructured thermites suggest that oxidation of aluminum nanoparticles occurs in a few microseconds. Such rapid reaction cannot be explained by a conventional diffusion-based mechanism. We present a rapid oxidation model of a spherical aluminum nanoparticle, using Cabrera-Mott moving boundary mechanism, and taking self-heating into account. In our model, electric potential solves the nonlinear Poisson equation. In contrast with the Coulomb potential, a “double-layer” type solution for the potential and self-heating leads to enhanced oxidation rates. At maximal reaction temperature of 2000 C, our model predicts …

Evaluation Of Single Electron Transfer Reduction Products Of 3-Oxoindoles As Antibacterial Agents, Debasish Bandyopadhyay, Irani Biswas, Subrata Laskar, Bidyut Basak

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

Objective: The objective of the present study is to assess the antibacterial properties of six indole derivatives viz, 3-(Naphth-1-y - methyl) –indole (II), 3-(1-Naphthylcarbonyl – indole (III), 3,3' –diformyl-2,2' –bis indole (IV), 1,4- (3,3' –di indolyl) – 1,4-dioxobutane (V), 3-benzoyl indole (VI) and 1,1 – bis – (3-indolyl)- ethane (VII) synthesized by single electron transfer reduction of 3-formylindole (I) against two Gram +ve and two Gram –ve bacteria which usually cause human infections.

Methods: Synthesis of 3-formyl indole from which the indole derivatives were prepared were further characterized by IR and NMR analysis. The six synthesized compounds were screened for …

Charge And Discharge Behaviour Of Li-Ion Batteries At Various Temperatures Containing Licoo2 Nanostructured Cathode Produced By Ccso, Y. Y. Mamyrbayeva, R. E. Beissenov, Mkhitar A. Hobosyan, S. E. Kumekov, Karen S. Martirosyan

Physics & Astronomy Faculty Publications

There are technical barriers for penetration market requesting rechargeable lithium-ion battery packs for portable devices that operate in extreme hot and cold environments. Many portable electronics are used in very cold (-40 °C) environments, and many medical devices need batteries that operate at high temperatures. Conventional Li-ion batteries start to suffer as the temperature drops below 0 °C and the internal impedance of the battery increases. Battery capacity also reduced during the higher/lower temperatures. The present work describes the laboratory made lithium ion battery behaviour features at different operation temperatures. The pouch-type battery was prepared by exploiting LiCoO2 cathode material …

Facile Molten-Salt Synthesis Of Double Perovskite La2bmno 6 Nanoparticles, Yuanbing Mao

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

Crystalline double perovskite La2BMnO6 (B = Ni and Co) nanoparticles with an average grain size of ∼64 nm were successfully prepared using a facile, environmentally friendly, scalable molten-salt reaction at 700 °C in air. Their composition and structural and magnetic properties have been characterized.

Tuning Of Alternative Splicing - Switch From Proto-Oncogene To Tumor Suppressor, Aleksandra Shchelkunova, Boris Ermolinsky, Meghan Boyle, Ivan Mendez, Michael Lehker, Karen S. Martirosyan, Alexander V. Kazansky

Physics & Astronomy Faculty Publications

STAT5B, a specific member of the ST AT family, is intimately associated with prostate tumor progression. While the full form of STAT5B is thought to promote tumor progression, a naturally occurring truncated isoform acts as a tumor suppressor. We previously demonstrated that truncated STAT5 is generated by insertion of an alternatively spliced exon and results in the introduction of an early termination codon. Present approaches targeting ST AT proteins based on inhibition of functional domains of STAT's, such as DNA-binding, cooperative binding (protein-protein interaction), dimerization and phosphorylation will halt the action of the entire gene, both the proto-oncogenic and tumor …

Tuning Of Alternative Splicing - Switch From Proto-Oncogene To Tumor Suppressor, Aleksandra Shchelkunova, Boris Ermolinsky, Meghan Boyle, Ivan Mendez, Michael Lehker, Karen S. Martirosyan, Alexander V. Kazanksy

Health & Biomedical Sciences Faculty Publications

STAT5B, a specific member of the STAT family, is intimately associated with prostate tumor progression. While the full form of STAT5B is thought to promote tumor progression, a naturally occurring truncated isoform acts as a tumor suppressor. We previously demonstrated that truncated STAT5 is generated by insertion of an alternatively spliced exon and results in the introduction of an early termination codon. Present approaches targeting STAT proteins based on inhibition of functional domains of STAT's, such as DNA-binding, cooperative binding (protein-protein interaction), dimerization and phosphorylation will halt the action of the entire gene, both the proto-oncogenic and tumor suppressor functions …

Completion Of Hankel Partial Contractions Of Extremal Type, Raúl E. Curto, Sang Hoon Lee, Jasang Yoon

School of Mathematical & Statistical Sciences Faculty Publications

We find concrete necessary and sufficient conditions for the existence of contractive completions of Hankel partial contractions of size 4 × 4 in the extremal case. Along the way we introduce a new approach that allows us to solve, algorithmically, the contractive completion problem for 4 × 4 Hankel matrices. As an application, we obtain a concrete example of a partially contractive 4 × 4 Hankel matrix, which does not admit a contractive completion.

The Collegian (2012-12-03), Joe Molina

UTB/TSC Archives - The Collegian [Newspaper]

Vol. 65, No. 14

Swift Follow-Up Observations Of Candidate Gravitational-Wave Transient Events, P. A. Evans, J. K. Fridriksson, N. Gehrels, J. Homan, Matthew Benacquista, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Malik Rakhmanov, Joseph D. Romano

Physics & Astronomy Faculty Publications

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 …

Measuring Learning Through Cross Sectional Testing, Steve Lovett, Jennie Johnson

Management Faculty Publications

The measurement of student learning is becoming increasingly important in U.S. higher education. One way to measure learning is through longitudinal testing, but this becomes especially difficult when applied to cumulative learning within programs in situations of low persistence. In particular, many Hispanic Serving Institutions (HSIs) find themselves in such situations. Cross sectional testing is a pragmatic alternative, so long as maturity and selection effects can be estimated. The purpose of this paper is to demonstrate the utility and mechanics of measuring learning through cross sectional testing.

Neoliberal Teacher Preparation: Conceptualising A Response In The Us Borderlands, Michael D. Guerrero, Peter Farruggio

Bilingual and Literacy Studies Faculty Publications

The current era of neoliberal capitalism has witnessed the domination of public education by business interests which openly promote the spirit of competition among schools, educators and students through a policy of high stakes accountability for immediately measurable educational outcomes. In the USA, this policy proposes to make teacher educator programmes accountable for the impact of their programme completers on student achievement, namely standardised test scores. Consequently, some programmes have begun to rethink their practices in an effort to avoid negative sanctions. Unfortunately, little empirical evidence of improvement is available to teacher educators, particularly those committed to the preparation of …

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 …

Development Of A Vibration And Temperature Measurement Device For Railroad Bearings, Andrea P. Arguelles

Theses and Dissertations - UTB/UTPA

Bearing related derailments cause very high cost and inconvenience to the railroad industry. Various wayside detection systems have been implemented to assess bearing condition and prevent premature failure. However, current devices fail to determine the internal condition of bearings or provide insight regarding the danger and severity of defects and abnormalities that may be present. To this end, a device combining both temperature and vibration detection was designed to be embedded in railroad bearing adapters. In order to efficiently design a railroad bearing condition-monitoring system, two factors that must be considered are the capabilities available to operate the different sensors …

School Type And Student Achievement: Does School Type Affect Student Achievement In Hidalgo County, Texas?, Krystal Estarei Garcia

Theses and Dissertations - UTB/UTPA

This study concentrates on identifying whether school type affects student achievement. Throughout this thesis, school type is the independent variable and student achievement is the dependent variable. School type was measured according to whether the school was classified as either a public school or charter school. In addition, school type was further defined according to the following variables: total academic and administrative staff, number of principals, number of assistant principals, school size, number of teachers, student teacher ratio, and student type. School expenditures, time, and method of teacher certification are the control variables. For the purpose of this thesis, student …

Selected Factors Related To The Mathematics Academic Achievement Of Eighth Grade English Language Learners, Anthony Garza

Theses and Dissertations - UTB/UTPA

The purpose of this study was to examine selected factors related to the 8th grade mathematics achievement levels of English Language Learner (ELL) students in selected South Texas middle schools. The dependent variable, ELL mathematics achievement, was measured by the ELL student’s raw score on the State of Texas Assessment of Academic Readiness (STAAR) or the State of Texas Assessment of Academic Readiness linguistically accommodated test (STAAR L). The factors examined in this study were 1) parent’s educational background, 2) socioeconomic status, 3) parental involvement status at school, 4) number of people in the household, 5) family structure, 6) primary …

Evidence Of Olfactory And Visual Learning In The Asian Citrus Psyllid, Diaphorina Citri Kuwayama (Hemiptera: Psyllidae), Dara G. Stockton

Theses and Dissertations - UTB/UTPA

Investigation of the mechanisms underlying learning and memory can be achieved through research on neurobiologically simplified invertebrate species. As such, insects have been used for decades as ideal models of olfactory learning. The current study aimed to investigate the mechanisms of chemosensory attraction in an invasive insect, Diaphorina citri, the Asian citrus psyllid (ACP), through manipulation of olfactory stimuli. After classical conditioning to a non-innate cue (vanilla extract), psyllids displayed enhanced feeding behavior. There was, however, an inverse relationship between olfactory “noise” and feeding behavior. Preliminary data suggests ACP may also be visual learners, as evidenced by trials attempting to …

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

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 …

The Impact Of Interest On Reading Motivation For A Struggling Mexican American Adolescent Reader, Abelardo Lopez Jr.

Theses and Dissertations - UTB/UTPA

This single subject qualitative case study investigated the impact interest had on reading motivation for a struggling Mexican American adolescent reader from the Rio Grande Valley region of South Texas. Moreover, the study’s findings found several factors that impacted the subject’s motivation to read; factors which impacted the subject’s reading motivation were associated with his home and school life environment, his attitudes towards literacy activities, and the teaching and learning engagements which occurred throughout the study.

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 …

Predicting College Success: An Analysis Of Graduating Students At The University Of Texas-Pan American, Esther G. Herrera

Theses and Dissertations - UTB/UTPA

Using inferential statistics, this thesis examines whether college experiences, pre-college experiences, and the institutional factors affect college success at the University of Texas-Pan American in Edinburg, Texas. Secondary data were used from the Graduating Student Survey administered by the Office of Institutional Research and Effectiveness at the University of Texas-Pan American for the years 2008-2009, 2009-2010, and 2010-2011. The findings indicate that college experiences do have an effect on college success (significant at .05 p-value); job after graduation serves as a better predictor of college success than competency; institutional factors also have a significant effect on college success, especially in …

Remediation In Mathematics: A Factor In The Retention Of Entering Freshmen At A Hispanic Serving Institution, Rolinda May Pena-Park

Theses and Dissertations - UTB/UTPA

Many institutions of higher education face a common challenge - retaining students in a time when higher education is of most importance as students must be prepared to compete in today's fast growing global market. Students are dropping out of college at an alarming rate due to the lack of academic readiness. The main area of academic deficiency is in the area of mathematics (National Center for Education Statistics, 2006). The purposes of this qualitative multiple case study were to explore the effectiveness of remediation courses in mathematics and identify the factors that influence success or failure of Hispanic students …

Inquiry-Based Science Education As Multiple Outcome Interdisciplinary Research And Learning (Moirl), Allan Feldman, Angela M. Chapman, Vanessa Vernaza-Hernández, Dilek Ozalp, Fayez Alshehri

Teaching and Learning Faculty Publications

The article provides the basis for a model of inquiry-based science education in which K-12 teachers’ and pupils’ engage in authentic science experiences as participants of a scientific research project, which we refer to as Multiple Outcome Interdisciplinary Research and Learning (MOIRL). We provide the basis for the model for inquiry based science education (IBSE) by first describing how the model came about through our 10 years of research on how people learn to do science in research groups. We then turn to the literature on the relationship among scientific inquiry, inquiry learning and MOIRL. As our case studies of …

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, Matthew Benacquista, Teviet Creighton, Mario C. Diaz, Soumya D. Mohanty, Volker Quetschke, Joseph D. Romano

Physics & Astronomy Faculty Publications

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

Physics & Astronomy Faculty Publications

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 …

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 & Statistical Sciences Faculty Publications

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). …

Reflexiones Sobre Lenguaje, Cultura Y Equidad En La Enseñanza De Matemáticas En Una Escuela Primaria Bilingüe De Estados Unidos, Sandra I. Musanti, Sylvia Celedón-Pattichis, Mary E. Marshall

Bilingual and Literacy Studies Faculty Publications

Esta investigación cualitativa explora las prácticas y percepciones de dos maestras (K-1), así como los asuntos de equidad implícitos en la integración curricular de problemas de matemáticas contextualizados para adecuar la enseñanza de estudiantes latinos que están aprendiendo inglés como segunda lengua. Este estudio se basa en tres enfoques: el enfoque cognitivo guiado de la enseñanza de matemáticas, el lenguaje y la cultura como recursos pedagógicos, y la enseñanza de matemáticas para la equidad. La investigación se desarrolla en el contexto de una iniciativa de desarrollo profesional situado entre maestras bilingües e investigadoras en una escuela primaria del suroeste de …

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

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

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 …

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

Physics & Astronomy Faculty Publications

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 …