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Transition Metal Mediated C-o Bond Cleavage: From Co2 Activation to Lignin Degradation

Transition Metal Mediated C-o Bond Cleavage: From Co2 Activation to Lignin Degradation

Date: August 2013
Creator: Liu, Cong
Description: CO2 activation and conversion mediated by transition metal (TM) catalysts were investigated. Homogeneous catalysis of the reverse water gas shift reaction CO2+H2→H2O+CO was studied as a means to reduce CO2. β-diketiminato metal models L'MI ( L' =C3N2H5-; M = first-row TMs) were considered as potential catalysts. The thermodynamics of prototypical reaction pathways were simulated using B3LYP/aug-cc-pVTZ. Results show that middle series metal complexes result in more thermodynamically favorable properties; therefore, more detailed thermodynamic and kinetic studies were carried out for Mn, Fe, and Co complexes. On the other hand, heterogeneous catalysis of the reduction of CO2 to CO was carried out on Fe, Co, Ni, and Cu surfaces, using the PBE functional. Reaction barriers were calculated using the climbing image nudged elastic band method. Late 3d and 4d transition metal ion (Fe, Co, Ni, Cu, Ru, Rh, Pd, and Ag) mediated activation of dimethyl ether was studied to investigate the intrinsic catalytic properties of metals for C-O bond cleavage. A set of density functional theory (DFT) methods (BLYP, B3LYP, M06, M06-L, B97-1, B97-D, TPSS, and PBE) with aug-cc-pVTZ basis sets was calibrated with CCSD(T)/CBS calculations on reaction energies and barriers.
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The Masculinity Masquerade: the Portrayal of Men in Modern Advertising

The Masculinity Masquerade: the Portrayal of Men in Modern Advertising

Date: August 2013
Creator: Harper, Savannah
Description: The depiction of gender in advertising is a topic of continuous discussion and research. The present study adds to past findings with an updated look at how men are represented in U.S. advertising media and the real effects these portrayals have on the male population under the theoretical framework of hegemony and social cognitive theory. This research is triangulated with a textual analysis of the ads found in the March 2013 editions of four popular print publications and three focus group sessions separated by sex (two all-male, one all-female), each of which is composed of a racially diverse group of undergraduate journalism and communications students from a large Southwestern university. The results of the textual analysis reveal little ethnic or physical diversity among male figures in advertising and distinguish six main profiles of masculinity, the most frequent of which is described as the "sophisticated man." The focus groups identify depictions of extreme muscularity and stereotypical male incompetence as the most negative representations, while humorous and hyperbolic portrayals of sexual prowess and hyper-masculinity are viewed positively as effective means of marketing to men.
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An Examination of Resnick's Model of Malingering: a Pai Study of Feigned Ptsd

An Examination of Resnick's Model of Malingering: a Pai Study of Feigned Ptsd

Date: August 2013
Creator: Wooley, Chelsea N.
Description: Malingered posttraumatic stress disorder (PTSD) poses a formidable clinical challenge in personal injury and disability cases because of the apparent ease in feigning PTSD and the supposed link (proximate cause) to the claimed damages. The effective assessment of feigned PTSD is particularly challenging because this diagnosis is both easier to fake than other Axis I disorders and more difficult to detect. As an additional confound, some patients with genuine PTSD produce highly variable, elevated profiles on multiscale inventories that are difficult to distinguish from feigned PTSD. The current study examined whether the Personality Assessment Inventory (PAI) can effectively differentiate between genuine and feigned PTSD in 109 inpatients from a trauma unit. The two most effective scales were the MAL and the NDS scales. As a primary focus, the current study was the first empirical investigation of Resnick's model of malingered PTSD that is comprised of three subtypes: pure malingering (pure-M), partial malingering (partial-M), and false imputation (false-I). The primary goal was to evaluate whether each feigning group was able to (a) effectively simulate PTSD symptoms and diagnoses and (b) avoid being classified as feigning. The partial-M group proved to be the best feigning group in achieving these two goals. Furthermore, ...
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Preschool Teachers' Self-reported Levels of Preparation for Classroom Behavior Management

Preschool Teachers' Self-reported Levels of Preparation for Classroom Behavior Management

Date: August 2013
Creator: Lohmann, Marla J.
Description: Research indicates that serious behavior problems begin during the early childhood years. The study examined the perceived preparedness of teachers related to behavior management as well as preschool teachers' usage of evidence-based prevention and intervention strategies. The data indicates that preschool teachers feel prepared for managing aggression in their classrooms and report utilizing evidence-based prevention and intervention strategies regularly. Additionally, the data shows a weak relationship between teacher variables and the likelihood of feeling prepared for managing aggression or utilizing evidence-based strategies. The results can be used to gain a better understanding of special education preschool teachers' training needs in regard to behavior management and managing behavior problems in the preschool classroom.
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An Investigation of Malingering and Defensiveness Using the Spanish Pai Among Spanish-speaking Hispanic American Outpatients

An Investigation of Malingering and Defensiveness Using the Spanish Pai Among Spanish-speaking Hispanic American Outpatients

Date: August 2013
Creator: Correa, Amor Alicia
Description: For response styles, malingering describes the deliberate production of feigned symptoms by persons seeking external gain such as financial compensation, exemption from duty, or leniency from the criminal justice system. In contradistinction, defensiveness occurs when patients attempt to downplay their symptoms of psychological impairment. Both of the aforementioned response styles can markedly affect the accuracy of diagnosis, especially on self-reports, such as multiscale inventories. As an important oversight, no studies have been conducted to examine the effect of culturally specific response styles on profile validity and the classification of malingering among Hispanic American clinical populations. The current study investigated whether the Spanish Personality Assessment Inventory (PAI) effectively distinguished between Spanish-speaking outpatient groups randomly assigned to honest, feigning, and defensive experimental conditions. In examining the results, PAI malingering indicators utilizing Rare Symptoms strategies (NIM and MAL) demonstrated moderate to large effect sizes. For defensiveness, Spanish PAI indicators also demonstrated moderate to very large effect sizes (M d = 1.27; range from 0.94 to 1.68). Regarding psychometric properties, Spanish PAI validity scales, provide adequate to good data on reliability and discriminant validity. Clinical utility of the Spanish PAI increases as different cut scores are employed.
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A Performance Guide to Arvo Pärt's Concerto Piccolo Über B-A-C-H for Trumpet, Strings, Harpsichord, and Piano

A Performance Guide to Arvo Pärt's Concerto Piccolo Über B-A-C-H for Trumpet, Strings, Harpsichord, and Piano

Date: August 2013
Creator: Bishop, James Martin
Description: Arvo Pärt's Concerto Piccolo über B-A-C-H for trumpet, strings, harpsichord, and piano is a brief yet challenging work in the trumpet repertoire. A carefully articulated performance guide is necessary to aid trumpeters in overcoming the numerous musical challenges presented in this piece. Currently, there is no resource that helps in solving performance choices and difficulties in this work. This first section of this document provides historical and contextual information on Arvo Pärt, his compositional output during his experimental period, and subsequently, Concerto Piccolo. The second section includes a performance analysis of the work, while the third gives trumpet players pedagogical suggestions and practical exercises for proper preparation of Concerto Piccolo. This guide presents performers with relevant background, analytical, and pedagogical information required for an informed and high-level performance.
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Synthesis and Design of Microwave Filters and Duplexers with Single and Dual Band Responses

Synthesis and Design of Microwave Filters and Duplexers with Single and Dual Band Responses

Date: August 2013
Creator: Mandal, Iman K.
Description: In this thesis the general Chebyshev filter synthesis procedure to generate transfer and reflection polynomials and coupling matrices were described. Key concepts such as coupled resonators, non-resonant nodes have been included. This is followed by microwave duplexer synthesis. Next, a technique to design dual band filter has been described including ways to achieve desired return loss and rejection levels at specific bands by manipulating the stopbands and transmission zeros. The concept of dual band filter synthesis has been applied on the synthesis of microwave duplexer to propose a method to synthesize dual band duplexers. Finally a numerical procedure using Cauchy method has been described to estimate the filter and duplexer polynomials from measured responses. The concepts in this thesis can be used to make microwave filters and duplexers more compact, efficient and cost effective.
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Southern Roots, Western Foundations: the Peculiar Institution and the Livestock Industry on the Northwestern Frontier of Texas, 1846-1864

Southern Roots, Western Foundations: the Peculiar Institution and the Livestock Industry on the Northwestern Frontier of Texas, 1846-1864

Access: Use of this item is restricted to the UNT Community.
Date: August 2012
Creator: Liles, Deborah Marie
Description: This dissertation challenges Charles W. Ramsdell's needless war theory, which argued that profitable slavery would not have existed west of the 98th meridian and that slavery would have died a natural death. It uses statistical information that is mined from the county tax records to show how slave-owners on the northwestern frontier of Texas raised livestock rather than market crops, before and during the Civil War. This enterprise was so strong that it not only continued to expand throughout this period, but it also became the foundation for the recovery of the Texas economy after the war.
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Computational Studies of Inorganic Systems with a Multiscale Modeling Approach: From Atomistic to Continuum Scale

Computational Studies of Inorganic Systems with a Multiscale Modeling Approach: From Atomistic to Continuum Scale

Date: August 2013
Creator: Olatunji-Ojo, Olayinka A.
Description: Multiscale modeling is an effective tool for integrating different computational methods, creating a way of modeling diverse chemical and physical phenomena. Presented are studies on a variety of chemical problems at different computational scales and also the combination of different computational methods to study a single phenomenon. The methods used encompass density functional theory (DFT), molecular dynamics (MD) simulations and finite element analysis (FEA). The DFT studies were conducted both on the molecular level and using plane-wave methods. The particular topics studied using DFT are the rational catalyst design of complexes for C—H bond activation, oxidation of nickel surfaces and the calculation of interaction properties of carbon dioxide containing systems directed towards carbon dioxide sequestration studies. Second and third row (typically precious metals) transition metal complexes are known to possess certain electronic features that define their structure and reactivity, and which are usually not observed in their first-row (base metal) congeners. Can these electronic features be conferred onto first-row transition metals with the aid of non-innocent and/or very high-field ligands? Using DFT, the impact of these electronic features upon methane C—H bond activation was modeled using the dipyridylazaallyl (smif) supporting ligand for late, first-row transition metal (M) imide, oxo and ...
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Cooperation-induced Criticality in Neural Networks

Cooperation-induced Criticality in Neural Networks

Date: August 2013
Creator: Zare, Marzieh
Description: The human brain is considered to be the most complex and powerful information-processing device in the known universe. The fundamental concepts behind the physics of complex systems motivate scientists to investigate the human brain as a collective property emerging from the interaction of thousand agents. In this dissertation, I investigate the emergence of cooperation-induced properties in a system of interacting units. I demonstrate that the neural network of my research generates a series of properties such as avalanche distribution in size and duration coinciding with the experimental results on neural networks both in vivo and in vitro. Focusing attention on temporal complexity and fractal index of the system, I discuss how to define an order parameter and phase transition. Criticality is assumed to correspond to the emergence of temporal complexity, interpreted as a manifestation of non-Poisson renewal dynamics. In addition, I study the transmission of information between two networks to confirm the criticality and discuss how the network topology changes over time in the light of Hebbian learning.
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